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HomeMy WebLinkAboutLUA-08-125_Report 02Denis Law Mayor November 14, 2013 Justin Lagers PNW Holdings, LLC 9725 SE 36th Street, Suite 214 Mercer Island, WA 98040 11 I')/ City of 1 ... : r: ft f'1 r1·1 r/rc· ), \ / r:'\ ~ '·,:,,...~·,..·.~!~~ Department of Community and Economic Development C.E."Chip"Vincent, Administrator SUBJECT: Receipt of Third Quarterly Maintenance and Monitoring Report Harmony Grove Preliminary Plat City of Renton File LUA 08-125 Dear Mr. Lagers: This letter is to inform you that on May 28th I received the third quarterly monitoring report for the mitigation project at Harmony Grove. The project appears to be meeting performance standards. Two copies of the fourth quarterly monitoring report were due to the City by August 30, 2013. Please submit copies of this report as soon as possible. If you have any questions I can be reached at (425) 430-7382. Sincerely, Cu ent Planning Division Cc: Ed Sewall, Sewall Wetland Consulting, Inc City of Renton File LUA08-125 Renton City Hall • 1055 South Grady Way • Renton, Washington 98057 • rentonwa.gov Sewall Wetland Consulting, Inc. May 28, 2013 Rocale Timmons City of Renton 276'11 Covington Way SE lf2 Covington WA 9l()42 Department of Community and Economic Development 1055 South Grady Way Renton, Washington 98057 Re: Harmony Grove -Year I-3'd Quarterly Report SWC Job#A5-209 Dear Rocale, Phare: 253-$9-{fi15 Fax: 253$2-4732 City of Rent F" _ on ,:1nr11na [J 'I . IVJy.jion ~i~ I 2 :; ZO!p This report describes the results of Sewall Wetland Consulting, Inc. third quarter monitoring of the Harmony Grove Wetland mitigation project. >, . ... . 36TH S[ 141ST -·s1 0 0 Vicinity Map S£ 140TH ST r ;<"I The site located off of 162 Ave SE between SE 136th St. and SE 135th St. in King County (parcel 1457500040). The site is located in the northeast portion of section 13, Township 23N, and Range 5 East. It is 4.01 acres and rectangular in shape. Hannony Grove ~\'ewa/1 Wetland Consulting, Inc. May 28, 2013 Page 2 of 7 1.0 WETLAND MITIGATION CONCEPT AND GOALS 1.1 Miligalion Concepl The proposed project included the expansion of the existing wetland by 2,557sf as well as enhancement of9,922sf of the previously degraded buffer area through the removal of Himalayan blackberry and the installation of a mix of native trees and shrubs. 1.2 Mitigation Goals 1.2.1 Create 2,557sf of wetland along the north edge of the wetland. 1.2.3 Enhance 9,922sf of buffer though blackberry removal and planting of native trees and shrubs. 2.0 INTRODUCTION Although the success and final outcome of wetland mitigation, restoration and enhancement projects is never guaranteed, certain procedures can be utilized to increase the probability of success. One of the most important procedures for success following proper design and installation is the establishment of a monitoring plan to track changes and developments within the system. Monitoring provides the opportunity to evaluate the success of planted material within the system and observe early establishment of pioneer and volunteer species. By observing the success of planted and volunteer species during the first five years of the project, it may be possible to speculate on the successional pathway taken, and general success of the project. Monitoring at the Hannony Grove mitigation area is to be conducted eight times over a five year period. Monitoring will be conducted four times the first year, and once a year for the following four years. This report represents the third quarter report for Year I. During each site visit the overall success and rigor of the installation plantings is to be evaluated. Observations will also be made for any exotic/invasive species or native volunteer vegetation which may have entered the area. In addition, the wetland creation areas will be monitored during the early growing season for proper wetland hydrology. Sampling methodology is described in section 4.0 below. Harmony Grove Sewall Wetland Consulting, Inc. May 28, 2013 Page 3 of7 3.0 STANDARDS OF SUCCESS As described in the approved plan, the standards of success for the project are as follows; 5.2 STANDARDS OF SUCCESS 5,2, 1 Standards of sucess for each of the Suffer Enhancement Area shall be as follows: a, Volunteer natlve. non-Invasive species will be Included as acceptable components of 111e mitigation succes and will count toward percent cover preformance standards. b, Success of the mltlgallon within the mitigation areas will be determined by Year 1: 100 % survival of all planted shrubs and trees Year 2: 80% survival of planted material Year 3: 80% survval of planted lrees and 55 % aerial shn.b coverage at the end of Year 3 Year 4: 80% cover of planted trees and 75 % aerial shrub coverage at the end of Year 4 Year 5: 80% survival of panted trees and 80% aerial shrub coverage at the end o! Year 5 c. Not more than 10% cover of non-native Invasive species "1tnln m~lgatlon area during any of the 5 year,;, 5.2.2 Standards oJ Success !or the Wetland Creation Area shall be as follows: a. Volunteer native. non-Invasive species will be Included as acceptable components oJ tne mitigation succes and will count toward percent cover preformance standards, b. Success of the mitigation within the mitigation areas will be determined by: Year 1: 100 % survival oJ all planted shrubs and trees. 50% grou'ld cover of herbaceous vegetation Year 2: 80% survival of planted material and 60% or greater ground cover oJ helbaceous vegetation Year 3: 80% survval of planted trees and 55 % aerial shrub coverage at the end of Year 3 Year 4: 80% cover of planted trees and 75 % aerial shrub coverage at the end of Year 4 Year 5: 80% survival of panted trees and 80% aerial shrub coverage at the end of Year 5 c. Not more than 10% cover of non-native Invasive species wltlln mltlgaUon area during any of the 5 years, d, Successful hydrology wll be determined by whether soil saturation or Inundation occurs during the early growing season. SpeclflcaHy, hydrology should meet tne Cfiterla as stated In the Department of Army Corp c Engineers delineation manual Including the western regional supplement. 4.0 SAMPLING METHODOLOGY Hannony Grove Sewall Wetland Consulting, Inc. May 28, 2013 Page 4 of'7 As described in the approved plan, the sampling methods for the project are as follows; Vegetation All the planted material In the mitigation area will be Inspected during each monitoring visit to determine the level of survival of the Installation. The health and vigor of the plants and the overall condition of the mitigation areas will be noted, Healthy. vigorous plant material will be documented to determine both overaU success of the plantings and lnd~ldual species success. Vegetation monitoring will be completed during each site visit of each monitoring year and will oe documented in the required monitoring reports, Additionally. peranent photo points wi! be estabolished to document vegetative reponse. and phOtos wiU be provide<l within the required monitoring reports. Hydrology Hydrology will be rnontto,oo weekly from March through May throughout the monitoring period until which point It has been determined tlult wetland hydrolegy criteria have been met In accordance with the Army Corp of Engineer,; guidance. Wetland hydrology will be consldere<l present ~ lnnundatlon or sal\lratlon to the surface Is present for 12.5 percent of the growing season, or approxlrnatly 31 consecudve days. Hydrology will be monitored by the Instillation of hydrology rnonltorlng wells. The locations of hydrology rnonltorlng wells will be lndlcate<l on a map within the monitoring report, 5.0 OBSERVATIONS AND DISCUSSION OF SITE CONDITIONS The following is our observations of the second quarter monitoring of the mitigation site taken on May 24, 2013. 5.1 THIRD QUARTER 5. I. I Survival Statistics for Installed Plant Material As required by the Year I criteria, the survival rate for all planted species is I 00% at this time. Herbaceous ground cover is I 00% in the wetland buffer areas. As was observed during the second quarter, the creation areas coverage on the eastern lobe is approximately 30% right now and primarily covered with leaf litter under standing water. The western lobe has saturated soils and as a result herbaceous cover is approximately 75%. 5 .1.2 Invasive vegetation Hannony Grove Sewall Wetland Consulting, Inc. May 28, 2013 !-'age 5 '!fl The enhanced buffer area was originally covered with blackberry. As a result, control of blackberry on this site will need to be closely monitored. Blackberry maintenance has been ongoing since the installation, and currently blackberry coverage (as well as all other weedy species) is <5%. This meets the criteria required of not more than 10% weedy species coverage. It was noted that many small blackberry sprouts are fonning in the western buffer area and we recommend maintenance ( spraying) by April to control the re-colonization of the blackberry. 5.1.3 Hydrology The wetland creation area consists of an eastern and western lobe along the north edge of the existing wetland. Our observations of the area on May 24, 2013 revealed the eastern lobe had standing water in depths from 1 "-5", clearly meeting the wetland hydrology criteria. The western lobe was saturated at a depth of -6", also meeting the wetland hydrology criteria. Based upon these observations the creation area is meeting wetland hydrology criteria in the growing season as required. Of note were the numerous tree frog tadpoles observed within the eastern lobe of the creation area. 6.0 RECOMMENDATIONS & CONCLUSION The site is meeting all of the monitoring requirements for the third quarter of Year l. The Year One 4th quarter monitoring is scheduled to take place in late August, 2013 with a report to the City to follow shortly. If you have any questions or need any additional information please contact me at (253) 859-0515 or by email at esewall@sewallwc.com. Sincerely, Sewall Wetland Consulting, Inc. Ed Sewall Senior Wetland Ecologist PWS #212 Hannony Grove Sewall Wetland Consulting, Inc. A hove: l,ooking west across the creation portion ofmltlgation site. A hove: Lookmg west across north end ofnutigalion site. May 28, 2013 Page 6 o/7 Harmony Grove Sewall Wetland Consulrin7,, Inc. Above: Looking east along the northern end of the mitigation site. f May 2fl, 20 I 3 Pa7,e 7 of7 A hove: Lookzng north along west side ofm1tigation site. /,ow shrub is salmonherry. -·, '·.:1·i: ·~ Sewall Wetland Consulting, Inc. May 28, 2013 Rocale Timmons City of Renton 27641 Covington WaySE#2 Covington WA 'ID!2 Department of Community and Economic Development 1055 South Grady Way Renton, Washington 98057 Re: Harmony Grove -Year 1-3ru Quarterly Report SWC Job#AS-209 Dear Rocale, Phorc: 25M59-0ili Fax: 2.:&!524732 This report describes the results of Sewall Wetland Consulting, Inc. third quarter monitoring of the Harmony Grove Wetland mitigation project. ~ , ~ )( I 12!tU St 1.1?11'() PL f.; ::; I S[ _ : l.l2NO A ;.;; ~T. '.;;r -"" -~Site '·· : Sf . 134.J H 7.1 . -,__ L:~f ';! d./: -~ ~ _· -i3~~f1 'i."°-1 ·.:: ~ : > T .... .J . ..... sr 36TH ~· 8 . , Vicinity Map SE SE 133 Ll4T 140TH ST r ~ . The site located off of 162 Ave SE between SE 136th St. and SE 135th St. in King County (parcel 1457500040). The site is located in the northeast portion of section 13, Township 23N, and Range 5 East. It is 4.01 acres and rectangular in shape. Harmony Grove Sewall Wetland Consulting, Inc. May 28, 2013 Page 2 of7 1.0 WETLAND MITIGATION CONCEPT AND GOALS 1.1 Mitigation Concept The proposed project included the expansion of the existing wetland by 2,557sf as well as enhancement of9,922sf of the previously degraded buffer area through the removal of Himalayan blackberry and the installation of a mix of native trees and shrubs. 1.2 Mitigation Goals 1.2.1 Create 2,557sf of wetland along the north edge of the wetland. 1.2 .3 Enhance 9 ,922sf of buffer though blackberry removal and planting of native trees and shrubs. 2.0 INTRODUCTION Although the success and final outcome of wetland mitigation, restoration and enhancement projects is never guaranteed, certain procedures can be utilized to increase the probability of success. One of the most important procedures for success following proper design and installation is the establishment of a monitoring plan to track changes and developments within the system. Monitoring provides the opportunity to evaluate the success of planted material within the system and observe early establishment of pioneer and volunteer species. By observing the success of planted and volunteer species during the first five years of the project, it may be possible to speculate on the successional pathway taken, and general success of the project. Monitoring at the Harmony Grove mitigation area is to be conducted eight times over a five year period. Monitoring will be conducted four times the first year, and once a year for the following four years. This report represents the third quarter report for Year 1. During each site visit the overall success and rigor of the installation plantings is to be evaluated. Observations will also be made for any exotic/invasive species or native volunteer vegetation which may have entered the area. In addition, the wetland creation areas will be monitored during the early growing season for proper wetland hydrology. Sampling methodology is described in section 4.0 below. Hannony Grove Sewall Wetland Com11/1mg, Inc. 3.0 STANDARDS OF SUCCESS May 28, 2013 Page 3 <l/7 As described in the approved plan, the standards of success for the project are as follows; 5.2 STANDARDS OF SUCCESS 5,2, 1 Standards of S1Jcess f& each of the Buffer Enhancement Area shall be as follows: a. Volunteer natlve. non.lnvaslve species wlll be lrn:luded as acceptable components of the mitigation succes amJ will count toward percent cover preformance standards, b, Success of the mlilgallon within the mitigation areas v.111 be determined oy Year 1: 100 % survival of all planted shrubs and trees Year 2: 80% survival of planted material Year 3: 80% sunaval or planted trees and 55 % aerial shrub coverage at the end of Year 3 Year 4: 80% cover of planted trees and 75 % aerial shrub coverage at the end of Vear 4 Year 5: 80% survival of panted trees and 80% aerial shrub coverage at the end of Year 5 c. Not more than 10% cover of non-<iatlve Invasive species wltnln mitigation area during any of the 5 years, 5.2.2 Standards of Success for the Wetland Creation Area shall be as follows: a. Volunteer native. norHnvaslve species will be Included as acceptable components of tM mitigation succes and will count toward percent cover preformance standards, b. Success of the mitigation within the mitigation areas wlll be determined oy: Year 1: 100 % survival of all planted shrubs and trees. 50% ground cover of hertlaceous vegetation Year 2: 80% survival of planted material and 60% or greater ground cover of herbaceous vegetation Year 3: 80% survival of planted trees and 55 % aerial shrub coverage al the end of Year 3 Year 4: 80% cover of planted trees and 75 % ae!lal shrub coverage at !he end of Year 4 Year 5: 80% survival of panted trees and 80% aerial shrub coverage at the end of Year 5 e, Nol more than 10% cover of non-<iatlve Invasive species within mitigation area during any of lhe 5 yean;, d, Successful hydrology wll be determined by whether soil saturation or Inundation oCCl.lrs during the early growing season. Speclflcally, hydrology should meet the cfiterla as stated In the Department of Army Corp c Engineers deBneatlon manual Including the western regional suoplemenl. 4.0 SAMPLING METHODOLOGY Hannony Grove Sewall Wetland Consulting, Inc. May 28, 2013 Page 4 ofl As described in the approved plan, the sampling methods for the project are as follows; Vegetation All the planted material In the mitigation area will be Inspected during each monltorlng visit to determine the level of survival of the Installation, The health and vigor of the plants and the overall condition of the mttlga!lon areas will be noted, Healthy, vigorous plant matertal will be documented to determine both overall success of the plantings and Individual species success. Vegetation monltorlng wll be completed during each site visit of each monltotlng year and will be documented in the required monitoring reports. Additionally, peranent pholO points will be eslabolished IO document vegetative reponse. and photos wiU be provoed within 1he reqJi~ monitoring reports. Hydrology Hydrology will be monitored weekly from March through May throughout the monitoring period until which point It has been determined that wetland hydrolegy criteria have been met In accordance with the Army Corp of Engineers guidance. Wetland hydrology will be considered present ~ lnnundatlon or saturation to the surface Is present for 12.5 percent of the growing season, or approxlmatly 31 consecutlve days. Hydrology will be monttored by the lnstlHatlon of hydrology monitoring wells. The locations of hydrology monltorlng wells will be Indicated on a map wlthl~ the monitoring report, 5.0 OBSERVATIONS AND DISCUSSION OF SITE CONDITIONS The following is our observations of the second quarter monitoring of the mitigation site taken on May 24, 2013. 5.1 THIRD QUARTER 5.1. l Survival Statistics for Installed Plant Material As required by the Year 1 criteria, the survival rate for all planted species is I 00% at this time. Herbaceous ground cover is 100% in the wetland buffer areas. As was observed during the second quarter, the creation areas coverage on the eastern lobe is approximately 30% right now and primarily covered with leaf litter under standing water. The western lobe has saturated soils and as a result herbaceous cover is approximately 75%. 5.1.2 Invasive vegetation Hamwny Grove ,)'ewa/1 Wetland Consulting, Inc. May 28, 2013 Page 5 qf7 The enhanced buffer area was originally covered with blackberry. As a result, control of blackberry on this site will need to be closely monitored. Blackberry maintenance has been ongoing since the installation, and currently blackberry coverage (as well as all other weedy species) is <5%. This meets the criteria required of not more than 10% weedy species coverage. It was noted that many small blackberry sprouts are fonning in the western buffer area and we recommend maintenance (spraying) by April to control the re-colonization of the blackberry. 5 .1.3 Hydrology The wetland creation area consists of an eastern and western lobe along the north edge of the existing wetland. Our observations of the area on May 24, 2013 revealed the eastern lobe had standing water in depths from I "-5", clearly meeting the wetland hydrology criteria. The western lobe was saturated at a depth of -6", also meeting the wetland hydrology criteria. Based upon these observations the creation area is meeting wetland hydrology criteria in the growing season as required. Of note were the numerous tree frog tadpoles observed within the eastern lobe of the creation area. 6.0 RECOMMENDATIONS & CONCLUSION The site is meeting all of the monitoring requirements for the third quarter of Year 1. The Year One 4th quarter monitoring is scheduled to take place in late August, 2013 with a report to the City to follow shortly. If you have any questions or need any additional information please contact me at (253) 859-0515 or by email at esewall@sewallwc.com. Sincerely, Sewall Wetland Consulting, Inc. Ed Sewall Senior Wetland Ecologist PWS #212 Harmony Grove Sewall Wetland Consultin?,, Inc. Above: Look111g west across the creation portion of'miligation site. Above: Look111g west across north end of'mitigation site. May 28, 2013 Page 6 ofl Hannony Grove ~\'etrn/1 Wetland Consulting, Inc. May 28, 2013 Page 7 of 7 Above: /J)()king east along the northern end of the mitigation site. r •:y' Above: rooking north along west side of mitigation site. /,ow shrub is sa/monherry. OFFICE OF THE HEARING EXAMINER KING COUNTY, WASHINGTON 400 Yesler Way, Room 404 Seattle, Washington 98104 Telephone (206) 296-4660 Facsimile (206) 296-1654 Email: hearex@metrokc.gov January 29, 2008 REPORT AND DECISION SUBJECT: Department of Development and Environmental Services File No. L05P0026 Proposed Ordinance No. 2007-0620 Location: Applicant: Intervenor: THREADGILL SUBDIVISION Preliminary Plat Application 13502 -162nd Avenue Southeast Eagle Creek Development, LLC represented by Bill H. Williamson Williamson Law Office 70 I -5th Avenue Seattle, Washington 98139 Telephone: (206) 292-0411 Facsimile: (206) 292-0313 Citizen's Alliance for a Responsible Evendell represented by Gwendolyn High P.O. Box 2936 Renton, Washington 98056 Telephone: (425) 336-4059 King County: Department of Development and Environmental Services (ODES) represented by Chad Tibbits 900 Oakesdale Avenue Southwest Renton, Washington 98055 Telephone: (206) 296-7194 Facsimile: (206) 296-7051 SUMMARY OF RECOMMENDATIONS/DECISION: Department's Preliminary Recommendation: Department's Final Recommendation: Examiner's Decision: Approve subject to conditions Approve subject to conditions (modified) Approve subject to conditions (modified) LOSP0026---Thrcadgill Subdivision EXAMINER PROCEEDINGS: Hearing Opened: Hearing Closed: Hearing Re-opened (for administrative purposes) and Closed: 2 December 18, 2007 January 22, 2008 January 25, 2008 Participants at the public hearing and the exhibits offered and entered are listed in the attached minutes. A verbatim recording of the hearing is available in the office of the King County Hearing Examiner. ISSUES AND TOPICS ADDRESSED: Surface water drainage Complete application SUMMARY OF DECISION: Traffic safety Student safe walking conditions A subdivision of 15 lots on 4.01 acres in the urban area is approved, subject to conditions. FINDINGS, CONCLUSIONS & DECISION: Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. General Information: Applicant: Engineer: STR: Location: Zoning: Acreage: Number of Lots: Eagle Creek Land Development, LLC Randy Goodwin 13701 SE 253'd Street Kent, WA 98042 206-730-9145 Ed McCarthy, P.E., P.S. 9957-171" Avenue SE Renton, WA 98059 425-271-5734 14-23-05 The site is located at 13502-162'd Avenue SE, at the southeast comer of 162"d Avenue SE and SE 135th Street intersection. R-4 4.01 acres 15 Density: Approximately 3.74 units per acre Lot Size: Approximately 6,000 to 10, 000 square feet in size Proposed Use: Single Family Detached Dwellings Sewage Disposal: The City of Renton Water Supply: King County Water District No. 90 Fire District: King County Fire District No. 39 School District: Issaquah School District No. 411 Complete Application Date: December 13, 2005 L05P0026-Threadgill Subdivision 3 2. Except as modified herein, the facts set forth in the King County Land Use Services Division's preliminary report to the King County Hearing Examiner for the December 18, 2007, public hearing are found to be correct and are incorporated herein by this reference. The LUSD staff recommends approval of the application, subject to conditions. The division's recommended conditions were modified at the January 8 and 22, 2008 public hearings. 3. The mitigated determination of environmental non-significance (MONS) issued on November 9, 2007 was appealed by the applicant. On December 18, 2007, the applicant withdrew its appeal. The conditions of the November 9, 2007 MONS are now incorporated in the proposed action. 4. Section F 3 of the preliminary report for the December 18, 2007 public hearing erroneously refers to the Soos Creek Subbasin of the Green River drainage basin. The subject property lies within the Maplewood, Orting Hills and Mainstem sub-basins of the Lower Cedar River basin. This error had no effect on the review of the proposed plat by DOES. 5. Section Hof the preliminary report for the December 18, 2007 public hearing was revised by the Land Use Services Division at the January 8, 2008 public hearing. The revised section is set forth in exhibit no. 18 in the hearing record. 6. In a letter dated January 7, 2008 (exh. no. 24) the applicant proposed revisions to the surface water drainage system. These revisions are, in part, a response to a recent hydraulic study prepared for Southeast 144th Street, and also respond to downstream concerns identified by residents of the neighborhood. To mitigate flooding problems identified downstream of the west basin of the Threadgill plat, and along Southeast 144th Street, the applicant's revised proposal is to provide Level 3 flow control of surface water discharged from the detention pond to be located in the southwest comer of the property. In addition, three options are offered by the applicant to address concerns downstream from the east basin of the subject property. Option 1 would bypass potential drainage problem areas immediately downstream from the northeast comer of the site. Option 2 would utilize a new storm pipe system within the right-of-way of Southeast 135th Street, and would provide improvements on private property to convey water from Southeast 135th Street to Southeast 136th Street. Option 3 would provide increased detention capacity (Level 3 flow control) for the east basin, but would not provide downstream improvements. The applicant and all nearby property owners who have expressed an opinion prefer that Option 1 be utilized for the discharge and conveyance of stormwater from the east basin. The review engineer also supports that option, and recommends that King County accept for maintenance the new conveyance system that would be constructed within the public right-of-way from the discharge point on 164th Avenue Southeast to the point on Southeast 136th Street where the new conveyance system will intersect with the current north-south channel approximately 160 feet east of 164th Avenue Southeast. A drainage adjustment is required for implementation of Option 1. 7. The downstream analysis provided by the applicant for surface water runoff from the west basin indicates that water is now discharged from the Threadgill property at its southwest comer, then crosses 162nd Avenue Southeast and travels to the west along Southeast 136th Street. It then turns south and travels to a wetland within the Plat of Liberty Grove Contiguous. Evidence presented by a property owner to the south states that the current drainage from the Threadgill Plat west basin now travels south on 162nd Avenue Southeast, and does not enter the Liberty Grove Contiguous wetland. L05P0026-Threadgill Subdivision 4 There are current flooding problems to the south, that are exacerbated by excessive water discharging from the Liberty Grove Contiguous wetland during certain storm events. Surface water discharge from the Threadgill property's west basin is required to follow its existing drainage course, unless a surface water adjustment is approved. A catch basin exists in the right-of-way of 162nd Avenue Southeast at Southeast 136th Street, from which a pipe leads west within Southeast 136th Street. However, it is possible that existing runoff from the southwest basin also travels, at least in part, south on 162nd Avenue Southeast within existing road side ditches. Diversion to the west of any portion of the surface water runoff that in fact flows south on 162nd Avenue Southeast would aggravate existing downstream problems and would conflict with SWDM requirements. The actual path of surface water from the west basin of the Threadgill property during various storm events can be determined during the process of reviewing final drainage plans. 8. The proposed development of 15 lots has received a certificate of traffic concurrency from the King County Department of Transportation. The number of trips generated during any peak hour by the Threadgill Plat is 16. This is below the thirty peak hour trips at any intersection which is the minimum threshold required to call for mitigation of traffic impacts at an affected intersection. The MDNS requires participation by this proposed development in the construction of 162nd Avenue Southeast from its present southerly terminus (near Liberty Gardens) to Southeast 144th Street. This requirement will enhance the interconnectivity of streets serving the neighborhood, and will reduce the number of vehicles traveling to and from this subdivision that will travel through the high accident location of Southeast I 28th Street and 160th Avenue Southeast. 9. The proposed development does not include construction of either Southeast 135th Street or Southeast 136th Street from 162nd Avenue Southeast to 164th Avenue Southeast. Although right-of-way will exist adjacent to this plat on both Southeast 135th and Southeast 136th Streets to allow for future construction, any decision to construct improvements to either the Southeast 135th Street or Southeast 136th Street rights-of-way between 162nd Avenue Southeast and 164th Avenue Southeast will be subject to future consideration. The Threadgill Plat will be served solely by a cul-de-sac street from 162nd Avenue Southeast to a "dead end" within the subject property. 10. It is proposed by King County Department of Transportation, and agreed by the applicant, to provide safe walking conditions for students who will walk to Liberty High School and Brierwood Elementary School by constructing a walkway on 162nd Avenue Southeast, from the southwest comer of the Threadgill subdivision to Southeast 137th Place within the Plat of Liberty Lane. Within Liberty Lane, Southeast 137th Place connects with a path to the east boundary of that property on the alignment of 164th Avenue Southeast, adjacent to Liberty High School. This route is reasonable and suitable for Liberty High School students. However, from Southeast 137th Place, Brierwood Elementary students would have to cross the high school grounds to 166th Avenue Southeast, then tum back north to reach Brierwood Elementary. It is unlikely that elementary school students would, in fact, walk south approximately 200 yards from the Threadgill plat entrance road to Liberty Lane, then retrace those 200 yards going back north on 166th Avenue Southeast. It is substantially more likely that the undeveloped right-of- way of Southeast 135th Street, or the undeveloped right-of-way of Southeast 136th Street, would be utilized to travel east and connect with 166th Avenue Southeast. The final engineering plans can identify what, if any, improvements are necessary and acceptable to King County DDES to provide safe walking conditions on either Southeast 135th Street or Southeast 136th Street to LOSP0026--Threadgill Subdivision 166th Avenue Southeast for students who will walk from the Threadgill subdivision to Brierwood Elementary School. 5 11. KCC 20.24.040 provides that DOES shall not commence review of any application until the applicant has submitted the materials and fees required for a complete application. The Intervenor in this proceeding contends that the Threadgill preliminary plat application was incomplete for failure to provide a certificate of water availability, a certificate of sewer availability, a certificate of transportation concurrency, density calculations and a tree inventory. (The Intervenor's contention includes a claim that certain certificates, that may have been valid when submitted, subsequently expired.) A King County Certificate of Water Availability for this property (then proposing a subdivision of23 lots) was issued by King County Water District No. 90 on December 13, 2004, and was filed with ODES with this subdivision application on December 13, 2005. The certificate was renewable after one year. A certificate of sewer availability for 15 lots on the property was issued by the City of Renton Wastewater Utility on July 14, 2005, and was also filed with DOES on December 13, 2005. The Certificate of Water Availability was re-issued by King County Water District No. 90 on January 7, 2008, and the Certificate of Sewer Availability issued by the City of Renton was confirmed as still valid by the issuer on January 7, 2008. A Certificate of Transportation Concurrency was issued by King County Road Services Division for 16 dwelling units on the Threadgill property on December 2, 2005 and was received by DOES on December 13, 2005. Subdivision Density and Dimension Calculations dated December 5, 2005 were filed by the applicant with DOES on December 13, 2005, and were re-filed on a revised ODES form on January 2, 2008. A site plan identifying the trees on the subject property was filed with DOES on December 13, 2005, as Sheet 2 of the subdivision plan. A tree retention plan and landscape plan are required with engineering plans for plat development. DOES determined that the subject application was complete on December 13, 2005. CONCLUSIONS: 1. If approved subject to the conditions recommended below, the proposed Threadgill subdivision will comply with the goals and objectives of the King County Comprehensive Plan, subdivision and zoning codes, and other official land use controls and policies of King County. 2. If approved subject to the conditions recommended below, this proposed subdivision will make appropriate provision for the public health, safety and general welfare, and for open spaces, drainage ways, streets, other public ways, transit stops, potable water supply, sanitary waste, parks and recreation, playgrounds, schools and school grounds and safe walking conditions for students who walk to school; and it will serve the public use and interest. 3. The conditions for final plat approval recommended below and contained in the mitigated determination of environmental non-significance are in the public interest and are reasonable and L05P0026---Thrcadgill Subdivision proportionate requirements necessary to mitigate the impacts of the development upon the environment. 6 4. The dedications of land or easements within and adjacent to the proposed plat, as required for final plat approval or as shown on the revised proposed preliminary plat submitted by the Applicant on December 11, 2006, are reasonable and necessary as a direct result of the development of this proposed plat, and are proportionate to the impacts of the development. 5. The applicant should apply for a surface water drainage adjustment to allow for the discharge of surface water from the east basin of the subject property to the right-of-way of 164th Avenue Southeast approximately as shown in exh. no. 29, from where the surface water would be conveyed south to the alignment of Southeast 136th Street, then east to the location where current flow from the east basin enters Southeast 136th Street at the existing channel. This adjustment would allow for the bypassing of current problem areas that could be impacted by additional flows from the Threadgill plat. As part of the surface water drainage application, the developer should request that King County accept and maintain the new conveyance system to be constructed within the public right-of-way of 164th Avenue Southeast and Southeast 136th Street. 6. Final engineering plans should provide for Level 3 detention of surface water prior to leaving the west basin of the proposed development, and should re-examine the discharge of existing flow from the west basin to determine the extent to which any existing flows are conveyed south along 162nd Avenue Southeast, rather than west along the alignment of Southeast 136th Street, during major storm events. This re-examination should be specifically reviewed by the DDES review engineer, to assure that no flow of surface water from 162nd Avenue Southeast is redirected to the west and enters the wetland within the Plat of Liberty Grove Contiguous. If any of the surface water flow from the west basin of the subject property is found to travel south along 162nd Avenue Soufheast under existing condition, drainage plans for reconstruction of 162nd Avenue Southeast and its extension shall be required to accommodate those flows and assure that there is no diversion of surface water to the west. 7. The proposed development, with the conditions of the MONS and the conditions of final plat approval set forth in this decision, improves road connectivity in the neighborhood in a manner that fully and proportionately mitigates the impacts of this development on traffic and vehicle safety at high accident locations on the Southeast 128th Street corridor. 8. Final engineering plans should provide a walkway to the east on the alignment of either Southeast 135th Street or Southeast 136th Street, to be utilized by students who will walk to Brierwood Elementary School, to provide a safe connection to 166th Avenue Southeast, for travel north to Brierwood. These walkways improvements should be reviewed by ODES for consistency with applicable King County standards for a safe walkway, and should be constructed, as approved, with the plat improvements. 9. The Threadgill application for preliminary plat approval meets the requirements of KCC 19A.08.150 and KCC 20.20.040. DDES correctly determined that this application was complete on December 13, 2005. The subsequent expiration and renewal of certificate of water and sewer availability did not affect the completeness of the application. The certificate of transportation concurrency was in effect at the time this application for subdivision approval was filed, and, therefore, remains valid while review of the application is pending. Appropriate density calculations and a tree inventory were submitted with the application. Modifications made to a L05P0026--Threadgill Subdivision 7 proposal during its review do not require submission of revised documents to maintain a complete application for the purpose of considering an application's eligibility for preliminary approval. DECISION: The proposed subdivision of Threadgill Plat, as revised and received December 11, 2006 is granted preliminary approval, subject to the following conditions of final plat approval: I. Compliance with all platting provisions of Title 19A of the King County Code. 2. All persons having an ownership interest in the subject property shall sign on the face of the final plat a dedication that includes the language set forth in King County Council Motion No. 5952. 3. The plat shall comply with the base density and minimum density requirements of the R-4 zone classification. All lots shall meet the minimum dimensional requirements of the R-4 zone classification or shall be as shown on the face of the approved preliminary plat, whichever is larger, except that minor revisions to the plat which do not result in substantial changes may be approved at the discretion of the Department of Development and Environment Services. Any plat boundary discrepancies shall be resolved to the satisfaction of ODES prior to the submittal of the final plat documents. As used in this condition, "discrepancy" is a boundary hiatus, an overlapping boundary or a physical appurtenance which indicates an encroachment, lines of possession or a conflict of title. 4. All construction and upgrading of public and private roads shall be done in accordance with the King County Road Standards established and adopted by Ordinance No. 11187, as amended (1993 KCRS). 5. The applicant must obtain the approval of the King County Fire Protection Engineer for the adequacy of the fire hydrant, water main, and fire flow standards of Chapter 17.08 of the King County Code. 6. Final plat approval shall require full compliance with the drainage provisions set forth in King County Code 9.04. Compliance may result in reducing the number and/or modifying the location of lots or tracts as shown on the preliminary approved plat. Preliminary review has identified the following conditions of approval which represent portions of the drainage requirements. All other applicable requirements in K.C.C. 9.04 and the Surface Water Design Manual (SWDM) must also be satisfied during engineering and final review. a. Drainage plans and analysis shall comply with the 2005 King County Surface Water Design Manual and applicable updates adopted by King County. ODES approval of the drainage and roadway plans is required prior to any construction. b. A surface water drainage adjustment shall be applied for to permit discharge from the Tract B (east) pond to 164th Avenue Southeast, at approximately the location shown on exh. no. 29, from where surface water shall be conveyed south to Southeast 136th Street, then approximately 160 feet east along Southeast 136th Street (preferably within the southern portion of the right-of-way) to the existing channel where the present flow from the east basin of the Threadgill property enters Southeast 136th Street. The adjustment application shall request that King County accept for maintenance the new conveyance LOSP0026---Threadgill Subdivision 8 system to be constructed within the public right-of-way. In the event a surface water adjustment that permits utilization of Option I substantially as presented in exh. no. 29 is denied, the hearing on this application shall be reopened for the limited purpose of re- evaluating surface water drainage alternatives for the east basin. c. Engineering plans for the west basin shall provide for detention of surface water to the Level 3 standard. The conveyance of water discharged from the west basin shall be re- examined to determine the extent, if any, to which existing flow travels south along the alignment of 162nd Avenue Southeast, south of Southeast 136th Street. No proportion of surface water that currently travels south on 162nd Avenue Southeast shall be diverted to the west along Southeast 136th Street. d. To implement the required Best Management Practices (BMP's) for treatment of storm water, the final engineering plans and technical information report (TIR.) shall clearly demonstrate compliance with all applicable design standards. The requirements for best management practices are outlined in Chapter 5 of the 2005 KCSWDM. The design engineer shall address the applicable requirements on the final engineering plans and provide all necessary documents for implementation. The final recorded plat shall include all required covenants, easements, notes, and other details to implement the required BMP's for site development. 7. The following road improvements are required to be constructed according to the 1993 King County Road Standards (KCRS): a. Road A shall be improved at a minimum to the urban minor access street standard. b. FRONTAGE: The frontage along 162"" Ave SE (east side) shall be improved at a minimum to the urban subcollector street standard. c. The Applicant shall widen 162"d Avenue SE, from the intersection of SE 136th Street to the northeasterly curb return of the intersection of SE 137th Place (the plat street for the Liberty Lane subdivision) to provide adequate walkway conditions for students who will walk to Liberty High School, and Maywood Middle School. These improvements shall consist of a minimum 22-foot wide roadway together with a walkway that is: (i) eight feet wide if directly abutting the traveled-way, or (ii.) five (5) feet wide if separated from the vehicle travel lane by an extruded curb (which requires an additional I-foot shy distance from the shoulder edge of the northbound travel lane-i.e .. 162"d Avenue SE would need to be at least 23-feet wide) or, (iii) five (5) feet wide if physically separated from the vehicle travel lane by a gravel shoulder. These improvements may include construction of full urban improvements ( curb, gutter and sidewalk) in lieu of these options. L05P0026-Threadgill Subdivision 9 Note: it is expected that similar improvements will also be conditions of approval for the proposed plats of Liberty Gardens L04P0034 and Cavalla L06POOOI, on appropriate portions of 162nd A venue Southeast. d. The applicant shall provide an improved walkway within the right-of-way of Southeast 135th Street or Southeast 136th Street to 164th Avenue Southeast, and continuing east, as necessary, to 166th Avenue Southeast to provide safe walking conditions for students who will walk to Brierwood Elementary School to the north. These improvements shall be the minimum necessary determined by DOES to provide safe walking conditions for elementary school students. e. Tract D shall be improved to the joint use driveway standard per Section 3.01 of the KCRS. This Tract shall be owned and maintained by the Lot owners served. f. Thirty feet of additional R/W shall be dedicated along the frontage of SE 135<h St; along with R/W radii at the northwest comer of Lot 15 and the northeast comer of Tract B. g. R/W radii shall also be dedicated at the southwest comer of Tract E and the southeast corner of Lot 6. h. Modifications to the above road conditions may be considered according to the variance provisions in Section 1.08 of the KCRS. 1. A conceptual frontage road improvement plan for the future construction of SE 136'" St, to the neighborhood collector street standard, shall be submitted with the engineering plans. This plan shall show the necessary R/W width for future construction of the road. Additional R/W needed to construct the future road shall be dedicated with the final plat. The intent of this condition is to insure that, following development, sufficient R/W will exist for future construction of SE l 36'h St to the east. 8. All utilities within proposed rights-of-way must be included within a franchise approved by the King County Council prior to final plat recording. 9. The applicant or subsequent owner shall comply with King County Code 14.75, Mitigation Payment System (MPS), by paying the required MPS fee and administration fee as determined by the applicable fee ordinance. The applicant has the option to either: (I) pay the MPS fee at the final plat recording, or (2) pay the MPS fee at the time of building permit issuance. If the first option is chosen, the fee paid shall be the fee in effect at the time of plat application and a note shall be placed on the face of the plat that reads, "All fees required by King County Code 14.75, Mitigation Payment System (MPS), have been paid." If the second option is chosen, the fee paid shall be the amount in effect as of the date of building permit application. 10. Lots within this subdivision are subject to King County Code 21A.43, which imposes impact fees to fund school system improvements needed to serve new development. As a condition of final approval, fifty percent (50%) of the impact fees due for the plat shall be assessed and collected immediately prior to the recording, using the fee schedules in effect when the plat receives final approval. The balance of the assessed fee shall be allocated evenly to the dwelling units in the plat and shall be collected prior to building permit issuance. L05P0026-Threadgill Subdivision 11. There shall be no direct vehicular access to or from SE 135'" Street or Southeast 136th Street from those lots which abut those streets. A note to this effect shall appear on the engineering plans and the final plat. 10 12. The proposed subdivision shall comply with the Critical Areas Code as outlined in K.C.C. 21A.24. Permanent survey marking and signs as specified in K.C.C. 21A.24.160 shall also be addressed prior to final plat approval. Temporary marking of critical areas and their buffers ( e.g., with bright orange construction fencing) sha11 be placed on the site and shall remain in place until all construction activities are completed. All offsite construction required as conditions of final plat approval shall likewise comply with the CAC. 13. Preliminary plat review has identified the following specific requirements which apply to this project. All other applicable requirements from K.C.C. 2 IA.24 shall also be addressed by the applicant. Wetlands A. Wetland A is a Category IV and requires a 50 foot buffer. The wetland is located in the southeastern portion of the site. The wetland is less than 2500 square feet and may be filled as shown on the site plan dated December 11, 2006. Mitigation is required for the wetland and buffer impacts. B. Wetland Bis a Category IV wetland and requires a 50 foot buffer. The wetland is located in the southwestern portion of the site. A portion of the wetland and buffer is located within unimproved right-of-way. This portion of the wetland and buffer may be impacted for required road improvements, as shown on the site plan dated December 11, 2006, subject to an approved mitigation plan. C. The 50 foot buffer for Wetland B may be reduced to 25 feet with an approved buffer enhancement/mitigation plan. D. A11 remaining wetlands and buffers shal1 be placed within Critical Areas Tracts (CAT) for long term protection. A split-railed fence or similar barrier sha11 be installed along the tract boundary. E. A 15 foot building set back line (BSBL) is required from the edge of CA T's and shall be shown on all affected lots. F. Additional road improvements are required within the unimproved 162nd Avenue right- of-way (ROW) located south of the proposed plat. Critical areas and buffers are located within this ROW. Impacts within the ROW may be permitted with mitigation. A mitigation plan will be required during engineering review. G. The engineering plans shall be routed to Critical Areas staff for review and approval of the critical area conditions. RESTRICTIONS FOR CRITICAL AREA TRACTS AND CRITICAL AREAS AND BUFFERS Dedication of a critical area tract/critical area and buffer conveys to the public a beneficial interest in the land within the tract/critical area and buffer. This interest includes the L05P0026-Threadgill Subdivision 11 preservation of native vegetation for all purposes that benefit the public health, safety and welfare, including control of surface water and erosion, maintenance of slope stability, and protection of plant and animal habitat. The critical area tract/critical area and buffer imposes upon all present and future owners and occupiers of the land subject to the tract/critical area and buffer the obligation, enforceable on behalf of the public by King County, to leave undisturbed all trees and other vegetation within the tract/critical area and buffer. The vegetation within the tract/critical area and buffer may not be cut, pruned, covered by fill, removed or damaged without approval in writing from the King County Department of Development and Environmental Services or its successor agency, unless otherwise provided by law. The common boundary between the tract/critical area and buffer and the area of development activity must be marked or otherwise flagged to the satisfaction of King County prior to any clearing, grading, building construction or other development activity on a lot subject to the critical area tract/critical area and buffer. The required marking or flagging shall remain in place until all development proposal activities in the vicinity of the sensitive area are completed. No building foundations are allowed beyond the required 15-foot building setback line, unless otherwise provided by law. 14. Suitable recreation space shall be provided consistent with the requirements ofK.C.C. 21 A.14.180 and K.C.C. 2 IA. 14.190 (i.e., sport court[ s ], children's play equipment, picnic table[s], benches, etc.). a. A detailed recreation space plan (i.e., location, area calculations, dimensions, landscape specs, equipment specs, etc.) shall be submitted for review and approval by DDES and King County Parks prior to or concurrent with the submittal of engineering plans. b. A performance bond for recreation space improvements shall be posted prior to recording of the plat. 15. A homeowners' association or other workable organization shall be established to the satisfaction of DDES which provides for the ownership and continued maintenance of the recreation and critical area tract(s). 16. Street trees shall be provided as follows (per KCRS 5.03 and K.C.C. 21A.16.050): a. Trees shall be planted at a rate of one tree for every 40 feet of frontage along all roads. Spacing may be modified to accommodate sight distance requirements for driveways and intersections. b. Trees shall be located within the street right-of-way and planted in accordance with Drawing No. 5-009 of the 1993 King County Road Standards, unless King County Department of Transportation determines that trees should not be located in the street right-of-way. c. If King County determines that the required street trees should not be located within the right-of-way, they shall be located no more than 20 feet from the street right-of-way line. d. The trees shall be owned and maintained by the abutting lot owners or the homeowners association or other workable organization unless the county has adopted a maintenance program. Ownership and maintenance shall be noted on the face of the final recorded plat. L05P0026--Threadgill Subdivision 12 e. The species of trees shall be approved by DDES iflocated within the right-of-way, and shall not include poplar, cottonwood, soft maples, gum, any fruit-bearing trees, or any other tree or shrub whose roots are likely to obstruct sanitary or storm sewers, or that is not compatible with overhead utility lines. f. The applicant shall submit a street tree plan and bond quantity sheet for review and approval by DDES prior to engineering plan approval. g. The applicant shall contact Metro Service Planning at (206) 684-1622 to determine if 162"• Avenue SE is on a bus route. If 162°• Avenue SE is a bus route, the street tree plan shall also be reviewed by Metro. h. The street trees must be installed and inspected, or a performance bond posted prior to recording of the plat. If a performance bond is posted, the street trees must be installed and inspected within one year ofrecording of the plat. At the time of inspection, if the trees are found to be installed per the approved plan, a maintenance bond must be submitted or the performance bond replaced with a maintenance bond, and held for one year. After one year, the maintenance bond may be released after DOES has completed a second inspection and determined that the trees have been kept healthy and thriving. 17. A landscape inspection fee shall also be submitted prior to plat recording. The inspection fee is subject to change based on the current county fees. 18. The following have been established by SEPA as necessary requirements to mitigate the adverse environmental impacts of this development. The applicants shall demonstrate compliance with these items prior to final approval. a. In order to address the incremental impacts of the development of the Threadgill plat, and the cumulative impacts with other pending development proposals in the area (Liberty Gardens, DDES File L04P0034, and Cavalla, DDES File L06P0001), on the High Accident Location (HAL) at the intersection of SE l 28'h Street/ 160th Avenue SE), the Applicant shall individually or jointly with other developers in the area construct an offsite extension of 162"• Avenue SE in general conformance with the conceptual plan submitted to DOES (dated: July 2, 2007) for the plat of Cavalla, from the current south terminus of 162"" Avenue SE (near the SE 138xx block) to SE 144°' Street. These improvements shall include no less than 22 feet of roadway paving, plus all associated appurtenances, and all storm drainage conveyance/ detention/treatment facilities as determined by DDES. These improvements shall include a tight-lining of the existing water-course located on the westerly half of the 162"' Avenue SE right-of-way. (KCC 14.80.030B) Note: a multi-party agreement between the three pending plat applicants (Threadgill, Liberty Gardens, and Cavalla) has been reached to implement this requirement. Portions of this improvement are located along the frontage of the Liberty Gardens and Cavalla plats, and will require additional roadway frontage improvements as conditions of those plats' approvals. b. In order to address the incremental impacts of the Threadgill development, by itself, on the HAL at the intersection of SE l 28'h Street/ 160'" Avenue SE, this applicant shall -in addition to the requirements of the preceding SEPA condition -dedicate any additional right-of-way required along the SE l 36'h Street margin of the site needed to construct - L05P0026-Thrcadgill Subdivision I J in the future, by others (private or public) -an extension of SE 136'h Street from l 62"d Avenue SE to l 66'h Avenue SE. The required additional right-of-way, as needed, may be based upon the preliminary road profile prepared by Baima & Holmburg dated 4/18/2005, and based upon a future 32-foot wide roadway with curb, gutter and sidewalks meeting applicable King County Road Standards, and any cut/fill slopes or retaining walls needed to allow others to construct this roadway. Any additional R/W needed to comply with this condition shall be determined prior to engineering plan approval and then shown as dedication on the final plat. (KCC 14.80.030B) 19. To implement K.C.C. 2 JA.38.230 which applies to the site, a detailed tree retention plan shall be submitted with the engineering plans for the subject plat. The tree retention plan (and engineering plans) shall be consistent with the requirements ofK.C.C. 21A.38.230. No clearing of the subject property is permitted until the final tree retention plan is approved by LUSD. Flagging and temporary fencing of trees to be retained shall be provided, consistent with K.C.C. 2 lA.38.230.B.4. The placement of impervious surfaces, fill material, excavation work, or the storage of construction materials is prohibited within the fenced areas around preserved trees, except for grading work permitted pursuant to K.C.C. 21A.38.230.B.4.d.(2). 20. A note shall be placed on the final plat indicating that the trees shown to be retained on the tree retention plan shall be maintained by the future owners of the proposed lots, consistent with K.C.C. 21A.38.230.B.6. (Note that the tree retention plan shall be included as part of the final engineering plans for the subject plat.) ORDERED this 29th day of January, 2008. James N. O'Connor King County Hearing Examiner pro tern NOTICE OF RIGHT TO APPEAL In order to appeal the decision of the Examiner, written notice of appeal must be filed with the Clerk of the King County Council with a fee of$250.00 (check payable to King County Office of Finance) on or before February 12, 2008. If a notice of appeal is filed, the original and six (6) copies of a written appeal statement specifying the basis for the appeal and argument in support of the appeal must be filed with the Clerk of the King County Council on or before February 19, 2008. Appeal statements may refer only to facts contained in the hearing record; new facts may not be presented on appeal. Filing requires actual delivery to the Office of the Clerk of the Council, Room 1025, King County Courthouse, 516 3'' Avenue, Seattle, Washington 98104, prior to the close of business ( 4:30 p.m.) on the date due. Prior mailing is not sufficient if actual receipt by the Clerk does not occur within the applicable time period. The Examiner does not have authority to extend the time period unless the Office of the Clerk is not open on the specified closing date, in which event delivery prior to the close of business on the next business day is sufficient to meet the filing requirement. If a written notice of appeal and filing fee are not filed within fourteen (14) calendar days of the date of this report, or if a written appeal statement and argument are not filed within twenty-one (21) calendar days of the date of this report, the decision of the hearing examiner contained herein shall be the final decision of King County without the need for further action by the Council. L05P002G--Threadgill Subdivision 14 MINUTES OF THE DECEMBER 18, 2007, JANUARY 8 AND 22, 2008 PUBLIC HEARING ON DEPARTMENT OF DEVELOPMENT AND ENVIRONMENTAL SERVICES FILE NO. L05P0026. James N. O'Connor was the Hearing Examiner in this matter. Participating in the hearing were Barbara Heavey, Chad Tibbits, Kristen Langley, Nick Gillen and Bruce Whittaker representing the Department; Bill H. Williamson and Shupe Holmberg, representing the Applicant; Gwendolyn High, Intervenor and Ty Pendergraft, Ed Sewell, Ed McCarthy, Doris Yepez, Michelle Hohlbein, John N. Case, Ed McCarthy, Henry Perrin, Keith Brown, and Gary Norris. The following Exhibits were offered and entered into the record on December 18, 2007: Exhibit No. I Prepared remarks on the pre-hearing conference on CARE's petition to intervene Exhibit No. 2 Citizen's statements of support of the CARE petition to intervene Exhibit No. 3 Letter from Mary and Donald Hamblin to the Hearing Examiner's Office dated December I 7, 2007 in support of the petition to intervene by CARE Exhibit No. 4 Threadgill vicinity development map The following Exhibits were offered and entered into the record on January 8, 2008: Exhibit No. 4A Annotated Threadgill vicinity development map by Shupe Holmberg Exhibit No. 5 Department of Development and Environmental Services File No. L05P0026 Exhibit No. 6 Department of Development and Environmental Services preliminary report dated Exhibit No. 7 December 18, 2007 Application dated December 13, 2005 Environmental Checklist dated December 13, 2005 Exhibit No. 8 Exhibit No. 9 SEPA Mitigated Determination of Non-Significance dated November 9, 2007 Exhibit No. 10 Affidavit of Posting indicating January 25, 2006 as date of posting and January 26, 2006 as the date the affidavit was received by DOES Exhibit No. 11 Revised preliminary plat map and site plan dated December 11, 2006 Exhibit No. 12 Revised Level I Downstream Analysis prepared by Baima & Holmberg, Inc., received December 11, 2006 Exhibit No. 13 Revised Critical Areas Report prepared by Sewall Wetland Consulting, Inc., received December 11, 2006 Exhibit No. 14 Revised Traffic Impact Analysis prepared by Gary Norris, received December 11, 2006 Exhibit No. 15 Landscape Plan (Conceptual Recreation Space Plan) prepared by Lane & Associates, received December 11, 2006 Exhibit No. 16 King County Water District No. 90 Certificate of Water Availability dated December 13, 2004 Exhibit No. 17 Submittal package by the Citizen's Alliance for a Responsible Evendell dated January 4,2008 Exhibit No. 18 Drainage narrative Exhibit No. 19 King County Department of Assessments Map Exhibit No. 20 Density and Dimension Calculations Exhibit No. 21 Email from Ty Pendergraft to Bill Williamson, Shupe Holmberg and the Goodwins dated January 7, 2008, re: Sewer Availability Exhibit No. 22 King County Certificate of Water Availability Exhibit No. 23 Response to C.A.R.E. issues/concerns Exhibit No. 24 Letter to Bruce Whittaker of DOES from Baima & Holmberg, Inc. dated January 7, 2008 re: Proposed Storrnwater Control Exhibit No. 25 Report from Ed McCarthy, PE, re: Downstream Drainage Analysis Exhibit No. 26 Aerial photograph showing the downstream conveyance system Exhibit No. 27 Basin map L05P0026--Threadgill Subdivision Exhibit No. 28 Exhibit No. 29 Exhibit No. 30 Exhibit No. 31 Exhibit No. 32 Exhibit No. 33 Exhibit No. 34 Exhibit No. 35 Exhibit No. 36 Exhibit No. 37 Exhibit No. 38 Exhibit No. 39 Liberty Grove and Liberty Grove Contiguous Street and Storm Drainage Plan (2 sheets) Sheet titled Option 1 -Alternate Storm Outfall Preliminary Road Improvement Plan Delivery Record/Receipts (3 pages) Letter to John & Nenita Ching, Donald & Andrea Gragg, Norm & Patricia Gammel from Curt W. Crawford, Manager, King County Stormwater Services Section dated April 13, 2007 DOES Permit Approval Actions Report Letter to James N. O'Connor from Peter H. Eberle dated December 17, 2007 Email to C.A.R.E. from Don & Mary Ellen Hamblin dated December I 7, 2007 Email to C.A.R.E. from Susan Oord dated December 16, 2007 Email to C.A.R.E. from Mike Ritchey dated December 16, 2007 Memo to DOES from Bob & Lynn Wilmot dated January 8, 2008 Letter to C.A.R.E. from John & Nenita Ching dated January 7, 2008 The following Exhibits were offered and entered into the record on January 22, 2008: Exhibit No. 40A Photo of Liberty Grove Contiguous drainage pond (under construction) Exhibit No. 40B Photo of path to the east on SE 135th Street alignment Exhibit No. 40C Photo ofHohlbein property Exhibit No. 41 HALS/HARS List Exhibit No. 42 Student walkways The following exhibit was entered into the record on January 25, 2008: 15 Exhibit No. 43 CARE: Threadgill Hearing prepared comments (January 22, 2008) with attachments JNOC:gao L05P0026 RPT ·@ King County Department of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 206-296-6600 TTY 206-296-7217 For alternate formats, call 206-296-6600. Drop-Off Cover Sheet for Land Use Services Division PROJECT NUMBER AND NAME IS NECESSARY Date Received by LUSD FOR ALL DROP-OFFS )< Project No. _LO 5Poo __ ;;.,_v ___ _ Project Name ~ROM (' . A. R 8. K.C. D.D.E.S. ADDITIONAL INFORMATION REQUESTED BY KING COUNTY STAFF (please print) Short Plat/ Plats Please specify itern(s) dropped-off Lot Line Adjustment Permit Please specify itern:.s1 dropp·?d 'J 1f Right of Way Permit Piease specify rte111,:s) dror,1.1eci c,tf· MAIN FILE COPY Clearinq / Grading Permit --Add1t:onal information requested Please specify :tem,:s·; drTjJl["2'._1 uff Otlier: \ ,.: )~--I, . Ei.r J. -!.-'--~ PLEASE NOTE: 1\II cJr-1~,1·, ·i: 1t :rnrs ·::.I! L'·(· l,~:,J(J::.'(J. iii:-:..:, !lie ,.:,::rnpuler· 1_111._!-:r· tl'1'2 uroJe:=-.; mnrbe1 th•·1:=:fclr'C, it 1s 1rn;:01tar:t '.he:: ·,h,:: to1:, p·:11iicl"l ·:}f 1111~: ,·~:.:+}k : pDJ>.:::rli ::". ',-r·t· ·,T·ll circ,p ,.:f: .i1·;vtlll'19 /•.ss1:Jt:'i,"·CC 111 l11,J:r1g c1 p•oJect 111J:11lwr Cl,eck out the DOES Wc/J site at ,., !·.I ~-·Ir· ·f :<I' Citizens' Alliance for a Responsible Evendell ! 425.336.4059 C P.O. Box 2936 · Renton, WA 98056 , highlands_neighbors@hotmail.com !'. Delivery Record/Receipt Document Delivered: CARE Response: Threadgill Subdivision Response -File No. L05P0026 Hearin O enin : Januar 8, 2008 Deliverer Section: 1, ))e.l:Joy-,J... L. coV-/L- (print name) delivered the document identified above to the following address: King County: Department of Development and Environmental Services (DD~ [c. r, · . , •. -'l[]··o· · , represented by Chad Tibbits and Barbara Heavey O Ls ~0 _; ..• ', c~ 1 900 Oakesdale Avenue Southwest Renton, Washington 98055 JAN O 4 'l008 Telephone: (206) 296·7194 Telephone: (206) 296-7222 Facsimile: (206) 296-7051 Facsimile: (206) 296-6613 D E S K.C.D .... on ____,/'---_l./_,__--=;;..D-=-l>--=-8"° ___ at _ __,_/-'/_·....:.· / _ _5=------ (date) (time) signed __:::J)=...o0C'='--'..~=--·-----"y{'-'..::_---'-"~=-=C......----.. --. .-•-' Receiver Section: I, ____________________ receiver the document identified above at the (print name) following address: King County: Department of Development and Environmental Services (ODES) represented by Chad Tibbits and Barbara Heavey 900 Oakesdale Avenue Southwest Renton, Washington 98055 Telephone: (206) 296-7194 Facsimile: (206) 296-7051 Telephone: (206) 296-7222 Facsimile: (206) 296-6613 on ____________ at __________ _ {date) (time) signed ___________________ _ C Citizens' Alliance for a Responsible Evendell f 425.336.4059 ,. Delivery Record/Receipt Document Delivered: P.O. Box 2936 ' Renton, WA 98056 : highlands_neighbors@hotmail.com !: CARE Response: Threadgill Subdivision Response -File No. L05P0026 Hearina Qpenina: January 8, 2008 Deliverer Section: I, ))dJoyA.A. L-cbU--1~ (print name) delivered the document identified above to the following address: King County: Department of Development and Environmental Services (DD' [c (r .. -. . . , , c'. '[JJ·o·:·. · represented by Chad Tibbits and Barbara Heavey D c;:', ( •.. _; ', ,'/ ,c;; 900 Oakesdale Avenue Southwest , Renton, Washington 98055 U ,.IA.N O 4 ZODA Telephone: (206) 296-7194 Telephone: (206) 296-7222 Facsimile: (206) 296-7051 Facsimile: (206) 296-6613 K.C. 0.0.E.S /-'1 -;;i.oDlJ ;/:;c. on -~-2~---~---at-~'--'-'--=____..,""'------- (date) (time) signed ~4)"'-<-Cl!!b=~,e. __ ;/-·_·~£~--~~~·-----__ Receiver Section: I, ___________________ receiver the document identified above at the (print name) following address: King County: Department of Development and Environmental Services (ODES) represented by Chad Tibbits and Barbara Heavey 900 Oakesdale Avenue Southwest Renton, Washington 98055 Telephone: (206) 296-7194 Facsimile: (206) 296-7051 Telephone: (206) 296-7222 Facsimile: (206) 296-6613 on ___________ at __________ _ (date) (time) signed ___________________ _ .. CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 CARE Response: Threadgill Subdivision Response -File No. L05P0026 Hearing Opening: January 8, 2008 Dear Parties, We are pleased to present our Response Package in the matter referenced above. Per the Rules of Procedure of the King County Hearing Examiner: - V. DEPARTMENT FILES: REPORTS, SPECIAL STUDIES. REVIEWS AND RESPONSES C. Optional Written Responses and Statements 1. When Due Parties and interested persons are encouraged to file with the examiner written responses to appeals, reports, and special studies, and to submit written statements (including briefs) which support or oppose an appeal or application to be heard by the examiner. Written responses or statements may be filed with the examiner's office not later than two business days prior to the scheduled opening of the hearing, or may be delivered to the examiner at the opening of the hearing, unless ordered otherwise by the examiner. 2. Service of Copies Copies of responses to an appeal shall be served upon the parties and the responsible County agency. Service shall be accomplished contemporaneously with filing with the examiner. Copies of responses to a department or division report shall be delivered to the department or division which issued the report prior to or concurrently with filing with the examiner. Copies of all responses, studies, briefs or other written statement should be served on o arties to the extent reasonable. we deliver this package in a timely manner to the following interested parties. OFFICE OF THE HEARING EXAMINER -KING COUNTY, WASHINGTON 400 Yesler Way, Room 404 Applicant: King County: Seattle, Washington 98104 Telephone (206) 296-4660 Facsimile (206) 296-1654 Email: hearex@metrokc.gov Eagle Creek Development, LLC represented by Bill H. Williamson Williamson Law Office 701 -5th Avenue Seattle, Washington 98139 Telephone: (206) 292-0411 Facsimile: (206) 292-0313 Department of Development and Environmental Services (DOES) represented by Chad Tibbits and Barbara Heavey 900 Oakesdale Avenue Southwest Renton, Washington 98055 Telephone: (206) 296-7194 Facsimile: (206) 296-7051 Telephone: (206) 296-7222 Facsimile: (206) 296-6613 Respectfully submitted, ~~/~ f-J,61-_ Gwendolyn High -president 1/312008 Page 1 of 24 CARE rlesponse: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 1. Who We Are Since November 2001, Citizens' Alliance for a Responsible Evendell (CARE), a Washington State non-profit corporation representing over 500 households in the East Renton Plateau Potential Annexation Area, has been meeting with and recording the concerns of the residents impacted by ongoing development activity in our community. We have an established record of acting as a conduit for the valid concerns of owners and residents of this community to the elected officials and departments of the government entities who hold jurisdiction here. CAR E's participation in this matter is in the public interest. We are primarily interested in ensuring coordinated and responsible development of the community consistent with state and local laws and regulations. We bring historical experience with, documentation of and familiarity with the existing conditions of our community as well as the detailed understanding of the probable negative impacts that must be adequately mitigated. Our intent is to facilitate the appropriately thorough consideration of the facts that bear on this proposed project. Gwendolyn High presents this documentation and will speak for CARE in this hearing. She is a data analyst, programmer and information technology project manager. Ms. High is co-founder and current president of CARE and has lead CARE's previous efforts as Intervenor in the in the matters of the Reclassificiation and Plat Applications for the Evendell (L01P0016 and L01TY401), Liberty Grove (L03P0006/L03TY403), Liberty Grove Contiguous (L03P0005/L03TY401) and Nichols Place (L03P0015) subdivision projects. 2. Our Methodology We have reviewed and cross referenced the application materials for Threadgill, Cavalla, Liberty Gardens, Evendell and Liberty Grove as related to the Threadgill site and anticipated impacts. Additionally, we have interviewed property owners and residents who will be affected by the changed conditions created as a result of site preparation, construction, and use associated with this proposed development and incorporated their testimony and documentary evidence in this Response. Text presented in this document enclosed by single border boxes is quoted from the exhibiUdocument named in the title (formatted thusly) of that section. Text presented in this document enclosed by double border boxes is quoted from the regulation named in the first line of that box. Page 2 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 3. Proposed Exhibits We request that each of the following documents be entered into the record individually, as we refer to them throughout our Response: o Evendell Plat Level 3 Downstream Drainage Analysis -Haozous Engineering (8/26/2002) [Evendell application file] o SE 144th Street Level 3 Downstream Drainage Analysis-Ed McCarthy (6/15/2007) Uointly prepared for Threadgill, Cavalla and Liberty Gardens applications] o Letter from Casey Engineering: Response to November 12, 2004 Plat Screening, Request for Additional Downstream Information (11/20/2003) [Liberty Grove application file] o Letter from ON Traffic Consultants: Threadgill/Cavalla/Liberty Gardens Response to KC Traffic Comments (4/17/2007) [Cavalla application file] o Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan -162na Ave SE -Proposed Extension (5/16/2007) [Cavalla application file] o Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan -Cavalla Preliminary Plat (5/16/2007) [Cavalla application file] o Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan (revised) -Liberty Gardens Preliminary Plat L04P0034 (5/16/2007) [Cavalla application file] o Preliminary Technical Information Report Proposed Plat of Cavalla (12/21/2005) [Cavalla application file] o King County IMAP/Hydrology Seti Areas Highly Susceptible to Groundwater Contamination o · King County IMAP/Hydrology Seti Critical Aquifer Recharge Zone o Jack Case Letters, Photos and Locator Legend Packet o Hohlbein Letter, Drawings and Photos Packet o High Accident Location Reports o King County Accident Report Data o Plat Screening Letter (7/26/2007) [Cavalla application file] o Letter from Barghausen: Resubmittal/Additional Information (11/20/2006) [Cavalla application file] o King County IMAP/Property lnfonmation Seti Shaded Elevation and 5-foot Contours o Donald and Andrea Gragg Packet o Doris Yepez Packet o Final Environmental Impact Statement-Tacoma-Cascade Pipeline April 26, 2007 (excerpts) o Landslide January 2001 Packet o EvendellNicholsPlaceComplaintRecord.doc Copies of these proposed Exhibits are provided to all parties as part of this Response. Page 3 of 24 CARE Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 4. What We Hope To Achieve CARE and its members are interested in ensuring coordinated and responsible development of our community consistent with state and local laws and regulations. CARE and its members are also concerned with protecting against damage to existing residences and properties as a result of site preparation, construction, and use associated with the Threadgill development. Recent developments in the area have resulted in tens of thousands of dollars of damage to surrounding properties and incalculable heartache. Such impacts would harm current residents' and owners' interests in protecting their property values, their safety, and their privacy and the quiet enjoyment of their property. We recognize that the owner of the Threadgill property has faced some relatively unusual challenges during the preparation of this application -a previous attempt to develop the property that was not implemented, coordination with other projects for required mitigation, and a change in responsible DOES planning staff. However much we may sympathize with their individual and personal difficulties in this effort, all parties in this matter still bear the same responsibility to ensure that this project is researched, planned, constructed and mitigated correctly and that the Public Interest is protected throughout the lifetime of this project. This application is incomplete, poorly reasoned and documented, and the mitigations proposed are based on an incomplete record. Thus, the mitigations proposed for impacts that can be reasonably expected are insufficient and will result in current residents and property owners being directly and adversely affected if the subject application is permitted and constructed according to the current ODES Preliminary Recommendations Report to the Hearing Examiner. Ultimately, our goal is to welcome a high quality, well constructed, well planned and thoroughly mitigated addition to our community that provides wonderful homes for our new neighbors-to-be, and does not cause unmitigated damage to the existing residents, owners, community and environment. Page 4 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 5. Response ODES Preliminary Report To Hearing Examiner ~=134ii4ZiiMMieiEiiM, Number of Lots: 11 The DDES report is inconsistent. It appears from the balance of the application materials that the project proposes 15 lots/homes. D.2 MONS ... this applicant shall -in addition to the requirements in the preceding SEPA condition -dedicate any additional right-of-way required along the SE 136"' Street margin of the site needed to construct -in the future, by others rivate or ublic -an extension of SE 136h Street from 162"" Ave SE to 1661" Ave SE. KCC 19A.08.150 Application requirements for preliminary plats, preliminary short plats and preliminary binding site plans. The following application requirements shall be required in addition to those application requirements described in K.C.C. 20.20.040: 4. The proposed layout of tots, tracts, right-of-way and easements, along with existing utilities and areas of proposed dedications; The SE 136'" St easements are not represented on any site plan, not reflected in the density calculations, nor the recreation calculations, and there is no representation that such a tract will leave sufficient setback potential on any of these tots. New Density Calculations and site plans reflecting the changes consequent to this MONS requirement of additional easements should be required for the consideration of this application The DOES report is incorrect. The site lies within the Maplewood, Orting Hills and Mainstem subbasins of the Lower Cedar River Basin. H.1 Subdivision Design Features ... KCC 21 A.14.020(8) requires lots for single detached dwellings to not have street frontage along two sides unless one of the said streets is a neighborhood collector or and arterial street. The 20-foot wide strip of property running along the northern property line adjacent to the SE 135"' Street shall be placed in a separate Tract or combined with the Recreation Tract to ensure the Ian is in conformance with KCC 21A.14.020 B ... KCC 21A.14.020 ' General layout standards. For residential developments in the UR and R zones: B. Except for corner lots, lots for single detached dwellings shall not have street frontage along two sides unless one of said streets is a nei hborhood collector street or an arterial street. Ord. 10870 362, 1993 . Page 5 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 KCC 19A.08.150 Application requirements for preliminary plats, preliminary short plats and preliminary binding site plans. The following application requirements shall be required in addition to those application requirements described in K.C.C. 20.20.040: 4. The proposed layout of lots, tracts, right-of-way and easements, along with existing utilities and areas of proposed dedications; KCC 21A.14.020 provides no authority for the remedy that ODES proposes. Lots "shall not have street frontage along two sides unless one of said streets is a neighborhood collector street or an arterial street." The current site plan should be rejected and a new one which complies with KCC 21A.14.020 required for consideration of this application. If the current site plan is not rejected, then: The 20 foot strip is not represented on any site plan, not reflected in the density calculations, nor the recreation calculations, and there is no representation that such a tract will leave sufficient setback potential on any of these lots. New Density Calculations and site plans reflecting the changes consequent to reflecting the changes consequent to ODES condition requiring of ea.sements on SE 136th St should be required for the consideration of this application. F .4 Subdivision Design Features The Level I Drainage Analysis shows that runoff form the west subbasin leaves the site at the southwest corner and flows south in the 162"" Ave Se roadway drainage system. This system is a combination of pipes and open ditches in the 162"" road R/W. The flow turns west along the south margin of SE 144th St, continuing west in a pipe system ultimatel discha in to Tributa 0307 over 1 mile from the site. The DOES report is misleading and incorrect. The westerly drainage is proposed to exit the site in a pipe under 162"' AVE SE, through a pipe under the Liberty Grove/Starwood development currently under construction. Water from that pipe outfalls into the wetland that is immediately to the east of and adjacent to the Liberty Grove/Starwood storrnwater pond that is on 160th Ave SE. This wetland flows directly out into the property to the south. The water will continue across nearly half a mile of private property, generally in a south easterly direction, before it more sharply to the east, crosses back under the to-be-constructed 162"" Ave SE, south across the Liberty Gardens site, then back east into the 162"" Ave SE R/W and finally into a King County maintained constructed stormwater conveyance on SE 144th St. KCCP T-305 Roadway safety improvements increase the safety of the traveling public by reducing the number and severity of accidents, providing refuge for pedestrians and bicyclists, providing positive traffic control, minimizing driver decisions, reducing hazardous roadway conditions, and reducing unexpected situations. Improvements of this type include, but are not limited to, pathways, traffic signals, tum and merge lanes, provisions for sight lines, removal of roadside obstacles, and im rovements to lessen the likelihood and im acts of localized floodin Appropriate neighborhood traffic control measures, land use, zoning, design and road standards and development conditions should be used to im rove safe , transit access and nonmotorized travel in residential nei hborhoods. Page 6 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 KCCP T-307 King County should encourage the development of highly connective, gridbased arterial and nonarterial road networks in new developments and areas of in-fill development. To this end, the county should: a. Make specific determinative findings to establish nonarterial grid system routes needed for public and emergency access in in-fill developments at the time of land-use permit review. b. Encourage new commercial, multifamily, and single-family residential developments to develop highly connective street networks to promote better accessibility by all modes. The use of cul-de-sacs should be discouraged, but where the are used, the should include destrian athwa s to connect with nearb streets. KCCP T-308 Development proposals should extend the public road system through dedication when the extension is in the public interest and is reasonably necessary as a result of the impacts of the development. The impacts that may warrant such an extension include, but are not limited to, impacts on neighborhood circulation, increases in the use of arterials for local vehicular trips, the reductions in traffic safety through uncoordinated and/or inadequately spaced street access to the arterials, and restrictions on the availabili of alternative eme enc access routes. KCCPl-310 ' As a condition of the approval of new development, the county should require the improvement of existing offsite roadways and undeveloped road rights-of-way, and/or other strategies to reduce demand on roads when the improvement or strategy is reasonably necessary as a result of the impacts of the development. The impacts that may warrant such improvements include, but are not limited to, those that create safety concerns, raise road operational issues or increase the number of residences served b a sin le New urban residential developments should provide recreation space, community facilities and neighborhood circulation for destrians and bic clists to increase o ortunities for h ical acti · . There is no indication on any site plan or other documentation that indicates the inclusion of any sidewalks, paths or indeed any pedestrian or other non-motorized facility as required by King County Comprehensive Plan and Code. New site plans demonstrating that the project meets the requirements for accommodation of all forms of nonmotorized transportation should be required for the consideration of this application 1.4.a Transportation Plans ... The Transportation certificate of Concurrency dated December 2, 2005, indicates that transportation improvements or strategies will be in place at the time of development, or that a financial commitment is in place to complete the im rovements or strate ies within six 6 ears, accordin to RCW 36. 70A.070 6 The Transportation Concurrency Certificate is expired as of 12/2/2006. It is therefore invalid. This application is incomplete, thus invalid, and should be rejected. New Transportation Concurrency Certificate should be required for the consideration of this application. The subject subdivision will be served by Briarwood Elementary School, Maywood Middle School and Liberty High School all located within the Issa uah School District No. 411. The site plan for this project was drastically revised in December 2006. The plat map submitted to the school district for consideration is dated 12/13/2005. The form received from the district is not based on valid current information. Page 7 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 New notification to (including valid site plans) and comment from the School District should be required for the consideration of this application. J.1.c Public Services: Schools: KCCP T-321 King County should seek to improve pedestrian safety both within residential areas and at arterials near pedestrian activity centers such as schools, retail centers, concentrations of housing, transit facilities and trails .... To foster safe walking conditions for students, King County should continue the School Walkway Program. C.A.R.E. strongly su orts the recommendation of DOES to re uire the construction of safe walkwa s for use b school children. KCC 21A.18.100 3. Access shall only be required to school bus stops that are within or adjacent to a proposed residential use of five or more dwelling units and that are identified by the affected school district in response to a Notice of Application. In order to allow school districts to identify school bus stops, the department shall send a Notice of Application to affected school districts on all a lications for residential uses of five or more dwellin units. No mention is made of the requirement listed on the School certificate that a improved bus stop on 160th Ave SE is required as the district will not enter this project. KCC 21A.18.100.B3 requires compliance with the District's needs. Site plan revision to reflect compliance with the School District's bus stop need should be required for the consideration of this application. The Certificate of Water Availability expired 12/13/2005. Thus, it existed in an expired state on the date DOES incorrectly deemed this application complete: 12/13/2005. KCC 20.20.040 states that the "department shall not commence review" until the application is complete. This application is incomplete, thus invalid, and should be rejected. New Certificate of Water Availability should be required for the consideration of this application . . A certificate of Sewer Availability, dated July 14, 2005, indicates this sewer provider's capability to serve the re osed develo men!. The Certificate of Sewer Availability expired 7/14/2006. It is therefore invalid. This application is incomplete, thus invalid, and should be rejected. New Certificate of Sewer Availability should be required for the consideration of this application . .. . A certificate of Water Availability, dated December 4, 2004, indicates this district's capability to serve the proposed develo men!. The Certificate of Water Availability expired 12/13/2005. ODES incorrectly deemed this application complete as of 12/13/2005. KCC 20.20.040 states that the 'department shall not commence review" until the application is complete. This application is incomplete, thus invalid, and should be rejected. New Certificate of Water Availability should be required for the consideration of this application. Page 8 of 24 CARE Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 Application Submission Form KCC 20.20.040 ' Application requirements. A. The department shall not commence review of any application as provided in this chapter until the applicant has submitted the materials and fees specified for complete applications. Applications for land use permits requiring Type 1 , 2, 3 or 4 decisions shall be considered complete as of the date of submittal upon determination by the department tllat the materials submitted meet the requirements of this section. Except as provided in K.C.C. 20.20.040. B, all land use permit applications described in K.C.C. 20.20.020 Exhibit A shall include the following: 1 . An application form provided by the department and completed by the applicant that allows the applicant to file a single application form for all land use permits requested by the applicant for the development proposal at the time the a lication is filed; No permit type is checked on this first form of the application process. No permit application has been officially and correctly sought. This application is incomplete, thus invalid, and should be rejected. New Application Submission Form should be required for the consideration of this application. Density Calculation Forms KCC 21A.14.180 On-elte recreation -space required. A. Residential developments of more than four units in the UR and R-4 through R-48 zones, stand-alone townhouse developments in the NB zone on property designated commercial outside of center in the urban area of more than four units, and mixed-use developments of more than four units, shall provide recreation space for leisure, play and sport activities as follows: 1. Residential subdivision, townhouses and apartments developed at a density of eight units or less r acre: three hundred ninet s uare feet r unit; King County Code requires standard calculations for the required recreational space. No recreation calculations were submitted with application. The standard, DDES supplied form sections are blank. DDES incorrectly deemed this application complete as of 12/13/2005. KCC 20.20.040 states that the "department shall not commence review" until the applica!ion is complete. This application is invalid and new Density Calculation Forms must be required for this application to be deemed complete. This application is incomplete, thus invalid, and should be rejected. New Density Calculations, including calculation for required Recreational Space should be required for the consideration of this application. Page 9 of 24 CARE Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 Tree Inventory KCC 16.82.156 Significant trees. Within the urban growth area: ... B. The applicant shall submit tree retention plans as follows: 1. A significant tree inventory shall be submitted for review before or with submittal of development permit applications. The tree inventory may be conducted by any method that reflects general locations, numbers and rou in of si nificant trees on-site; and King County Code requires a Tree inventory must be submitted with application. No Tree inventory exists in the application file. ODES incorrectly deemed this application complete as of 1211312005. KCC 20.20.040 states that the "department shall not commence review' until the application is complete. This application is invalid and a true and correct Tree Inventory must be required for this application to be deemed complete. This application is incomplete, thus invalid, and should be rejected. A valid Tree Inventory should be required for the consideration of this application. Threadgill Plat Level I Downstream Drainage Analysis Though there is some confusion on the ODES Report to the Hearing Examiner and elsewhere as to the actual number of lots being proposed, the majority of references, including the site plan, indicate that this application is for 15 lots. Page 3, paragraph 2 The drainage plan for the plat shows that runoff from the Threadgill property will be collected in a 12-inch diameter pipe and conveyed through the Liberty Grove site, separate from runoff collected at Liberty Grove. Stormwater from this pipe will discharge to the wetland on Tract C of Liberty Grove (location 8). No plans from Liberty Grove application are included in this application to document that the pipe under the Liberty Grove site actually exists. Uncontrolled discharge into wetland at Liberty Grove violates the sensitive areas ordinances of King County. From the wetland, the applicant proposes uncontrolled discharge across properties to the south and east with extensive drainage complaint records and known hydrology issues. This "natural' water course crosses at least 9 parcels and nearly half a mile pf private properties -including crossing the R/W for proposed extension of 162"• -twice -and continues across the proposed Liberty Gardens site before it finally enters the constructed conveyance system on SE 144'" St. Because of the anticipated worsening of known drainage issues along this "natural" course as proposed, and since 162nd Ave Se will be extended per MONS conditions, all the western basin drainage should be conveyed along the lo- be-constructed 162"• Ave SE and all the newly constructed conveyances adequately sized and configured to accommodate this flow properly. Runoff from the wetland and the remaining area in the eastern portion of the site flows to a side of 164'" Avenue SE. Page 10 of 24 CARE Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 The referenced ditch is rudimentary, primitive and utterly incapable of accommodating flow from the proposed project. Please see Doris Yepez Packet for photos of this ditch. Page 4. paragraph 4 ... 30 inch diameter concrete pipe at the north fence line of Liberty High School. .. . . . 30 inch diameter CMP with trash rack that apparently discharges to the school's stomiwater pond . . . . 20 inch overflow pipe ... . . . 42 inch diameteroutfall i e ... We were unable to obtain documentary evidence confirming the containment level of the Liberty High School stom,water facilities described here. However, it appears from this description alone that this is not a Level II facility. We think it may be a Level Ill facility. We request that confimiation of the specifics of the Liberty High School stormwater facilities be required and that if it is detemiined to have been constructed as a Level Ill facility, Threadgill stormwater facilities should also be required to be constructed at Level 111. Page 6. paragraph 3 ... I recommend that the proposed pond m the easterly drainage discharge to a t1ghtlme or to a new culvert and re- graded ditch that replaces the existing culvert and ditch at Locations 23 through 24 (Figure 4). The existing ditch between Locations 23 and 24 has high sots and could overflow with high flows, presenting a risk of flooding to the residence to the south. We assume that there are more pages in the Level I Downstream Analysis, but the narrative describing the subsequent proposed drainage path is missing from the copy of the report that is contained in the application file. Page 6 is the last narrative page. We offer the following comments without benefit of review and reference to the missing pages. The risk of flooding identified in the quotation above is not the only one. The proposed course (as presented in their Figure 4) continues past Location 24, through a cross culvert under SE 135th St, and enters a private conveyance system across thre private properties before entering the unimproved RNJ for SE 136" St. These pipes are not county installed or maintained and are not adequate for any additional flow. Please see Hohlbein Letter, Drawings and Photos Packet we submit today for further documentation of the current configuration of this private conveyance as well as the outstanding issues and concerns. We intend to call the Hohlbeins as witnesses later in this Hearing. Also, please see the King County IMAP/Property Information SeV Shaded Elevation and 5-foot Contours we submit today for further documentation of the extreme topographical circumstances of the project site and the eastern drainage. Drainage Complaints 91-1147, 91-0064 and 97-1493 Nothing has ever been done to alleviate persistent, significant re-occurring problems on the properties. Drainage Complaints 93-0724, 90-0931, 87-0496 and 95-0715 Nothing has ever been done to alleviate persistent, significant re-occurring problems on the properties whose conveyances applicants propose to use, without improvement, to carry 100% of the project's easterly drainage. Drainage Complaints 97-1493 and 00-0666 Nothing has ever been done to alleviate persistent, significant re--0ccurring problems from the conveyance system along 1451 " St where part of the easterly drainage will flow. New review, investigation and documentation of analysis of all drainage complaints from any parcel in or affected by either proposed course of drainage from the Threadgill site should be required for the consideration of this application. Page 11 of 24 CARE Response: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 Threadgill Plat Critical Areas Report The lot is bordered on the north by SE 135 St, the south by 135 St, the east by 162 west. l This statement is incorrect. It should read: The lot is bordered on the north by the partially unim~roved right of way for a potential SE 1351" St, the south by the unimproved right of way for a potential SE 136 St, the west by 162"" Ave SE and by primitive unpaved private 164th Ave SE on the east. This statement is an incomplete and misleading quotation of the official definition. It should read: Alderwood Association: Moderately well drained undulating to hilly soils that have dense, very slowly permeable glacial till at a depth of 20 to 40 inches; on uplands and terraces. The impermeability of soils in our community results in intense sheet flows and other hydrological characteristics that have not been adequately documented or considered, and thus inadequate mitigations have been proposed for this project. This statement is an incomplete and misleading. Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan - 162nd Ave SE-Proposed Extension J5/16/2007) [Cavalla application file] we submitted today, states as a consequence of the extension of 162 Ave SE, there will be unavoidable impacts to two Type 3 streams and proposes a contribution of $97,645.08 to the King County mitigation payment system to compensate. 3.2.2 Wetland A scores 24 for functionality, has area of 1031sf and King County Code requires a 50 foot buffer. 3.2.3 Wetland B scores 22 for functionality, has area of 4572sf and King County Code requires a 50 foot buffer. Applicant proposes to fill the higher functioning Wetland A and mitigate for that fill in the lower functioning Wetland 8, but at the same time cut the required buffer for the 'improved' Wetland 8 to 25 ft or half the required buffer. KCCP E-107 The protection of lands where development would pose hazards to health, property, important ecological functions or environmental quality shall be achieved through acquisition, enhancement, incentive programs and appropriate regulations. The following natural landscape features are particularly susceptible and should be protected: c. Wetlands and their protective buffers; d. Aquatic areas, including streams, lakes, saltwater shorelines and their protective buffers; . Critical A uifer Rechar e Areas; It is illogical and disingenuous to say "we will mitigate for the filled Wetland A by improving Wetland B" and then immediately and directly degrading the value and function of Wetland B by slashing the required buffer. Additionally, proposed fill and buffer reduction is in direct conflict with the King County Comprehensive Plan and the Page 12 of 24 CARE Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 Reconnaissance Report #13 Lower Cedar River Basin which we submit today (more detail contained below) and should be forbidden. Worksheet for Wetland B Datapoint 1 Data oint meets cnteria of a 'urisdictional wetland?: Yes No Worksheet for Wetland B Datapoint 2 Data oint meets cnteria of a ·urisdictional wetland?: Yes No Worksheets are incomplete and all analysis dependant on them is invalid. A new Critical Areas Report should be required to be submitted for reconsideration of this application. Cavalla Preliminary Technical Information Report - Reconnaissance Report #13 Lower Cedar River Basin Page 1 -Section I -Paragraph 2 & 3 The effects of development are most apparent where stonm drainage is routed over the valley walls. Impervious surfaces on the plateau have increased the rate and the volume of stonn runoff, resulting in substantial erosion, siltation, and flooding below. In addition. erosion and siltation have damaged or destroyed habitat in many tributaries, threatening the survival of the fish. Habitat and water quality throughout the basin are also threatened by the filling of wetlands ... Maintaining this quality should be a high prionty in the future basin planning capital improvement projects. Recommendations in the Lower Cedar River Basin included: 1) designing and constructing appropriately sized RID and other drainage facilities; 2) establishing stricter land use policies regarding floodplains, wetlands and gravel mining; 3)conducting more detailed and comprehensive hydraulic/hydrologic analyses of proposed developments; and 4 reventin dama e to the natural draina es stems ... Emphasis reproduced here exactly as from the original. The project site is in the Newcastle planning area. Page 13 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 Page 3 -Section Ill.A -Paragraph 4 The Lower Cedar River Valley has a high potential for erosion due to steep slopes and the existence of a clay layer that promotes soil failures. In addition, the confined nature of tributary channels between steep hillslopes promotes bank erosion during high flows. Numerous recent landslides are evident along the cliffs of many of the steep tributaries and along the main stem of the Cedar River. These have been accelerated by the removal of vegetation and the routin of concentrated storm flows over the stee slo s in areas where develo men! has occurred. Page 3 -Section Ill.A -Paragraph 6 Another type of tributary collects surface water from urbanized areas, pastureland, and wooded areas. Tributaries 0302, 0307, and 0312 are examples of this type of tributary. They are intermittent (depending on rainfall), shorter in length, flow through shallower channels that are steeper on the bluffs and transport more material during times of high flows. Some of the worst problems located in field investigations (see Appendix C for a full listing) occur in this type of tributa . The Threadgill site contributes flow to Tributary 0307. Page 5 -Section 111.B -Paragraph 2 Future problems will be similar to these, as commercial and residential developments increase flow rates and volumes by decreasing natural storage and infiltration. This is expected to occur if wetlands on the upper plateau are encroached upon or lost ... The preservation of wetlands and streambank vegetation and the attenuation of storm flows are essential in this basin. Page 5 -Section Ill C 1.b Serious instream erosion and subsequent downstream sedimentation. These have been caused by three main factors: 1) runoff from residential developments on the bluffs above the valley, 2) compacted pastureland due to livestock, and 3) runoff from the impervious areas originating at gravel pits. These problems will continue and worsen until m~i ative ste s are taken. Undersized rechannelized streams. Tributaries on the valley floor are too small to carry the increased flows originating in develo d areas alon the to s of the bluffs. Page 6 -Section Ill C.3.a Sedimentation of pools and riffles and cementing of gravels. These problems, the result of severe erosion and the transport of bed load material, have been caused by upland developments in the basin and the presence of impervious surfaces, which increase the rate and the quantity of surface runoff. Sedimentation and cementing o1 gravels in the stream beds destroy natural spawning and rearing habitats. On Tributary 0307 at river mile .40 and Tributary 0305 at river miles .95, 1.20, and 1. 70, recent high flows have eroded the streambed at least one foot, contributin to a serious siltation roblem downstream. Discouraging or eliminating the routing of stormwater over cliffs, unless adequate tightline systems can be constructed to conve flows in a safe nonerosive manner to the bottom of the cliffs Decreasing peak flows by constructing larger R/D facilities to lessen the landslide and erosion occurrence along tributa slo es. Page 8 -Section IV.C.1 Conduct a detailed, comprehensive hydraulic/hydrologic analysis of any proposed developments to determine the impacts on the drainage courses downstream. This is especially critical for areas in the upper bluffs and plateau, which drain over stee sensitive banks into the Cedar River. Page 14of24 CARE-Response: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 Conduct a study of the impact of locating infiltration ponds utilized near the edge of the bluffs to determine their effect on see a e faces on the lower face of the bluffs. Page 8 · Section IV.C.3 Require the tightlining of storm drainage down steep slopes and sensitive areas when they can not be directed away from slopes. This is done by piping the flow down the slope and discharging it at the bottom with adequate energy dissipation. Many of the intermittent tributaries flowing down the banks should be tightlined as urban development increases flow to them. Construct new RID ponds with filter berms to improve water quality and reduce fine sediment loads. New RID ponds should have two cells wtth ravel-berm filters and ve elated swales at the inlet and outlet. Page 8 -Section IV.C 5 Maintain natural vegetation on streambanks and floodplains. This is especially important for relatively flat channels flowing on the plateau before they reach the steep bluffs because these channels and their floodplains will attenuate flows durin times of hea runoff. Page C-12 -Recommendations Column for all Tributary 0307 records o Mitigate development related high flows o Provide adequate RID o Increase RID capacity at all delivery points o Reduce release rate below channel scour rate o Construct retention facilities in area at these sites. This report identifies challenging conditions in our community and the factors that lead to degradation of the Lower Cedar River Basin as well as the specific recommendations for how to ensure new development here does not negatively impact existing properties and the Lower Cedar River Basin. Recommendations are made in direct reference to the preservation of the health of the Federally protected Salmonid species habitiat -particularly spawning and rearing habitat. These King County recommendations have been ignored in the preparation and consideration of this application. KCCP E-107 The protection of lands where development would pose hazards to health, property, important ecological functions or environmental quality shall be achieved through acquisition, enhancement, incentive programs and appropriate regulations. The following natural landscape features are particularly susceptible and should be protected: c. Wetlands and their protective buffers; d. Aquatic areas, including streams, lakes, saltwater shorelines and their protective buffers; . Critical A uifer Rechar e Areas; - KCCP E-119 1 King County shall use incentives, regulations and programs to manage its water resources (Puget Sound, rivers, streams, lakes, freshwater and marine wetlands and ground water) and to protect and enhance their multiple beneficial uses -including fish and wildlife habitat, flood and erosion control, water quality control and sediment transport, water supply, energy production, transportation, recreational opportunities and scenic beauty. Use of water resources for one ur ose should, to the fullest extent racticable, reserve o ortunities for other uses. Page 15 of 24 CARE Response: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 KCCP E-120 Development shall support continued ecological and hydrologic functioning of water resources and should not have a significant adverse impact on water quality or water quantity, or sediment transport and should maintain base flows, natural water level fluctuations, roundwater rechar e in Critical A uifer Rechar e Areas and fish and wildlife habitat. Landslide January 2001 Packet As vividly detailed in several of the Drainage Complaints we have discussed in the Response and further discussed in the Reconnaissance Report #13 Lower Cedar River Basin report, groundwater issues are an on-going challenge throughout our community, but even these complaints can not convey the awesome scope of this problem. We offer photos from this incredible event as well as the email thread record of CARE's investigation and correspondence of this event with several responsible King County employees, some of whom we intend to call as witnesses later in this Hearing. King County IMAP/Hydrology Seti Areas Highly Susceptible to Groundwater Contamination and King County IMAP/Hydrology Seti Critical Aquifer Recharge Zone KCCP E-152 , King County shall identify areas in unincorporated King County that are considered Critical Aquifer Recharge Areas and maintain a map that designates these areas. The county shall update this map periodically w~h new information from ado ted roundwater and wellhead rotection studies and other relevant sources. KCCP E-153 ' King County should protect the quality and quantity of ground water countywide by: a. Implementing adopted Groundwater Management Plans; b. Reviewing and implementing approved Wellhead Protection Programs in conjunction with cities, state agencies and groundwater purveyors; c. Developing, with affected jurisdictions, best management practices for development and for forestry, agriculture, and mining operations based on adopted Groundwater Management Plans and Wellhead Protection Programs. The goals of these practices should be to promote aquifer recharge quality and to strive for no net reduction of recharge to groundwater quantity; and d. Refinin r ulations to rotect Critical KCCP E-154 King County should protect groundwater recharge quantity by promoting methods that infiltrate runoff where site conditions permit, except where potential groundwater contamination cannot be prevented by pollution source controls and stormwater retreatment. None of the downstream drainage reports and drainage complaint records submitted by the applicant or by us today provide a complete and cohesive representation of the hydrological characteristics of the site or of the sites that will be impact by this project. However, when they are considered together and in light of the Reconnaissance Report #13 Lower Cedar River Basin, the Areas Highly Susceptible to Groundwater Contamination and the Critical Aquifer Recharge Zone maps , a much more "real" picture begins to emerge. All mention of sheet flow and groundwater issues in the materials we discuss today have been characterized as persistent, pervasive and recurrent problems. Documentation of impacts from recent development in the area and the major 2006 landslide begin to give the scale of the impacts we can reasonably expect to see from this project. Page 16 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 A new Level Ill Downstream Drainage Analysis demonstrating compliance with the recommendations of the Reconnaissance Report #13 Lower Cedar River Basin report and KCCP E-107, E-119 and E-120 should be required to be submitted for reconsideration of this application. The proposed fill, mitigation and buffer reduction for Wetlands A and B should be forbidden as proposed. Cavalla Preliminary Technical Information Report - Drainage Complaint 97-206 Runoff from the natural drainage course of the Threadgill westerly basin discharges here. Owner reports that the properties can not be developed because the lots do not 'perc". The NDAP complaint evaluation memo states "As development continues in the approximately 60 acre drainage basin north of his property, more drainage water has been routed south into the pond located just northwest of his property which then drains east and south around the edge of his property." The investigating engineer rated this problem as a 14 for the reporting owner and two neighbors' impacts including: garage, septic system and yard damage to two properties. Owner reports that the for the first 15 years the septic system was fine, but that he has burned out four pumps within three years due to increased groundwater flows. The pond not noted in this report is not mentioned in the Level I Downstream Analysis submitted by the applicant nor Level Ill drainage report that we submit today, but it appears to be located very near #25 on the Level I Downstream Analysis Figure 4 map originally submitted with this application. The Donald and Andrea Gragg Packet we submit today documents the fact that the Hamilton Place subdivision project was required by King County to install additional drainage mitigations on the Gragg's property in an attempt to alleviate impacts from their project. The Grapps still face worsening conditions as documented by their letter March 18, 2007, also included in the packet. Hamilton Place was developed by KBS Construction, who is developing Cavalla, but this mitigation is not mentioned anywhere we could find in their application package. Additionally, the Gragg letter of March 18, 2007 is addressed to Ed McCarthy P.E. of Haozous Engineering who prepared the Level Ill Downstream Analysis for all three projects which we submit today as well as Level I Downstream Analysis submitted by the applicant for Threadgill. Neither report discloses this communication nor the outstanding issues at the Gragg's and their neighbors' properties. We intend to call Donald and Andrea Gragg as witnesses later in this Hearing. A new Level Ill Downstream Drainage Analysis demonstrating that negative impacts to the properties listed in Drainage Complaint 97-206 and located the same drainage course will be fully mitigated should be required to be submitted for reconsideration of this application. Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan {revised) - Liberty Gardens Preliminary Plat L04P0034 (5/16/2007) [Cavalla application file] The Off Site Mitigation Fee-In-Lieu is calculated at to $70,113.22. These calculations were submitted without consideration of the recommendations of the Reconaissance Report #13 Lower Cedar River Basin. Additionally, there has so far been a complete lack of consideration that the extension of 162"' Ave SE will intrude into Area Highly Susceptible to Groundwater Contamination, and into the Critical Aquifer Recharge zone. New Mitigation Fee Calculations should be required for reconsideration of this application. Page 17 of24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan -Cavalla Preliminary Plat (5/16/2007) [Cavalla application file] The Off Site Mitigation Fee-In-Lieu is calculated at $20,469.18. These calculations were submitted without consideration of the recommendations of the Reconaissance Report #13 Lower Cedar River Basin. Additionally, there has so far been a complete lack of consideration that the extension of 162"" Ave SE will intrude into Area Highly Susceptible to Groundwater Contamination, and into the Critical Aquifer Recharge zone. New Mitigation Fee Calculations should be required for reconsideration of this application. Letter from Chad Amour, LLC.: Conceptual Wetland Mitigation Plan -162nd Ave SE -Proposed Extension (5/16/2007) [Cavalla application file] The Off Site Mitigation Fee-In-Lieu is calculated at $97,645.08. These calculations were submitted without consideration of the recommendations of the Reconaissance Report #13 Lower Cedar River Basin. Additionally, there has so far been a complete lack of consideration that the extension of 162"• Ave SE will intrude into Area Highly Susceptible to Groundwater Contamination, and into the Critical Aquifer Recharge zone. New Mitigation Fee Calculations should be required for reconsideration of this application. Final Environmental Impact Statement -Tacoma-Cascade Pipeline April 26, 2007 (excerpts) 2.2.2 Preferred Alternative The Preferred Alternative (see Figures 2-2 and 2-3) would be approximately 19.1 miles long. It would begin at the SSP, generally follow 160th Avenue SE or 164th Avenue SE north, and cross SR 18. There is also an option for the Preferred Alternative to continue on 164th Place SE, turn northwest on Covington Way SE, cross SR 18, and turn west on SE 272nd Street to 156th Place SE. It would then follow 156th Place SE, 156th Avenue SE, SE 224th Street, 148th Avenue SE, SE 192nd Street, and 140th Avenue SE to the SR 169 crossing. There is also an option in this area that would run cross-country on private property from near the intersection of 140th Way SE and SE 156th Street north to the SR 169 crossing. The Preferred Alternative would continue east on the paved Cedar River Trail. North of SR 169, the pipeline would travel north along 149th Avenue SE, Jones Road, and along 154th Place SE, then cross-country through a King County-owned parcel, along 156th Avenue SE, SE 144'" Street, and 16oth Avenue SE to SE 128th Street The pipeline would then run east on SE 1281" Street and then north on 176th Avenue SE to SR 900 in the May Valley area. From the May Valley area, the pipeline route would follow SR 900 northeast to the BIP. In south Issaquah, there are options along SR 900 to run cross-country, roughly parallel to a Puget Sound Energy (PSE) right-of-way. The jurisdictions along the Preferred Alternative include the cities of Covington, Renton, and Issaquah, and uninco orated Kin Coun . Whatever the final fee calculations for the extension of 162"" Ave SE indicate, we request that these funds be pooled jointly with other such fees from all three of these applications (Threadgill, Cavalla, and Liberty Gardens), funds from the Cascade Water Alliance's Tacoma-Cascade Pipeline mitigations (please see Final Environmental Impact Statement -Tacoma-Cascade Pipeline April 26, 2007 (excerpts) we submit today), as well as funds contributed from the King County Mitigation Fee Program so that a comprehensive solution to the storrnwater conveyance inadequacies so vividly illustrated in all the drainage reports can finally be addressed. Alternatively, we request that these same sets of funds should be pooled and used to construct the most operationally functionally combination of Options recommended in the SE 1441 " Street Level 3 Downstream Drainage Analysis we submit to the record today. Page 18 of24 CARE Response: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 Letter from DN Traffic Consultants: Threadgill/Cavalla/Liberty Gardens Response to KC Traffic Comments (4/17/2007) [Cavalla application file] All the traffic volume maps appear to be invalid and thus all conclusions are equally invalid. These maps indicate that all traffic calculations are based on road configurations that do not include the proposed extension of 162"' Ave SE. Also, SE 1361" St does not continue past the site to the east as indicated in the maps. All traffic impact analyses must be recalculated and submitted for reconsideration with this application. Traffic Impact Analysis for The Plats of Threadgill/Cavalla/Liberty Gardens - October 31, 2006 All the traffic volume maps appear to be invalid and thus all conclusions are equally invalid. These maps and all text and calculations presented in the TIA are based on road configurations that do not include the proposed extension of 162"' Ave SE. This TIA is invalid and obsolete. Additionally, we find no consideration of the following questions: -Is the proposed intersection far enough from the currently existing intersection of 161" Ave SE on 1441 ". Particularly in consideration of the other intersections in the immediate vicinity (161" Ave SE, 1601 " Ave SE and 164th Ave SE) as well as the traffic flow patterns from the retail enterprise of Alpine Nursery located at the comer of 1441" and 161 81 , what kind of tum lane, tum pocket, signage etc. should be required for the safe and smooth function of 144'" after extension of 162nd? Will there be funds sufficient to construct all these necessary improvements for the safe and smooth function of 1441" after extension of 162nd? What facility improvements such as a guard rail or wall will be installed on the south side of 1441 " to prevent a car landing in current residents back yard. The substantial increased risk to life and property that will be borne by the owners and residents of the property directly south of this proposed intersection is disproportionate to all the surrounding community and all due care must be extended to prevent harm to them. New Traffic Impact Analyses should be required to incorporate the evidence presented in this Response for reconsideration with this application. Letter from Barghausen: Resubmittal/Additional Information (11/20/2006) [Cavalla application file] The following were required by ODES for the consideration of the Cavalla project, but not for the Threadgill application. We have not listed each item; only those we are confident apply to Threadgill as well. o Please show how the 3: 1 length to width water quality ratio is to be achieved in the drainage facility. o The Subdivision Technical Committee has noted in our review to date that an evaluation of the impacts of three pending plats: Cavalla (L06P0001), Liberty Gardens (L04P0034) and Threadgill (L05P0026) will have an impact on a listed High Accident Location at the intersection of Southeast 1281 " Street/162"' Avenue Southeast o Please demonstrate that buffers being used to protect the offsite wetlands are correctly using the current King County Critical Areas standards located in KCC 21A.24. o Conceptual Significant Tree Retention Plan (mitigation); Submit a conceptual significant tree retention plan and/or mitigation plan for the plat. o Walkways: Provide an inventory map (i.e. existing conditions -widths surface type, etc.) of the walking routes to the elementary, middle school/junior high schools and/or the appropriate bus stop locations associated with each school. Identify any improvements necessary to provide safe walking conditions. Page 19 of 24 • · CAR.E Response: Threadgill Subdivision Response -File No. LOSP0026 January 8, 2008 Since these projects ultimately discharge to the same water course i.e. the Cedar River, and since they are jointly constructing the extension of 162nd Ave SE, and since these additional requirements are largely lied to that extension, the Threadgill application should be held to the same standard and corresponding level of detail required for the consideration of this application. Letter from Casey Engineering: Response to November 12, 2004 Plat Screening, Request for Additional Downstream Information (11/20/2003) [Liberty Grove application file] The Liberty Grove Contiguous applicant submitted additional information response to staff request due to concerns of the known drainage issues and complaints in the westerly drainage of the Threadgill project. Sites of additional data correspond to points 2 through 20 on the Level I Figure 4 map originally submitted with this application. The Threadgill application should be held to the same standard and corresponding level of detail required by DOES staff for the Liberty Grove Contiguous, Cavalla and Liberty Gardens applications for the consideration of this application. SE 144th Street Level 3 Downstream Drainage Analysis -Ed McCarthy (6/15/2007) [jointly prepared for Threadgill, Cavalla and Liberty Gardens applications] This report lists as a resource the Evendell Level I Downstream Analysis, but not the Evendell Plat Level 3 Downstream Drainage Analysis -Haozous Engineering (8/26/2002) [Evendell application file] that we submit today. Roadway flooding along SE 144 St would be considered as 'severe roadway flooding problem" according to KC Standards Kin Count De rtment of Natural Resources Janua 2005 due to the fcllowin conditions: 2.4 Flooding locations and flood flow paths This section details of flooding locations in the easterly basin drainage of the Threadgill project that were not identified or addressed in the Threadgill Level I Downstream Analysis. 3.1 On-site Level 3 Detention When downstream sever roadway flooding is of concern, Level 3 stormwater detention standards are often included in the drainage design for new development as a stomnwater mitigation. Providing this type of mitigation has been used with success on several projects in King County. Level 3 detention standards would likely adequately mitigate the impacts of flooding for the proposed projects on downstream flooding. Adequately mitigating the flooding problem, at minimum, requires that runoff form the projects not aggravate the existing level or duration of flooding or create new flooding. The main disadvantage to providing Level 3 detention as a flooding mitigation is that while existing problems are icall not a ravated, the roblems are not solved. Page 20 of 24 , " CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 3.2, 3.3 and 3.4 These sections detail alternative option sets for solving mitigating the impacts of the extension of 162"" Ave Se and the existing drainage problems along SE 1441 • St and SE 1451 h St that were never raised or proposed for the Threadgill application as submitted. A new Level Ill Downstream Drainage Analysis demonstrating that the issues of "severe roadway flooding problem" on SE 144th St, the recurrent flooding in the easterly basin drainage of the Threadgill project identified in the SE 144th Street Level 3 Downstream Drainage Analysis will be fully mitigated, and that the most operationally functionally combination of Options recommended in the SE 144th Street Level 3 Downstream Drainage Analysis will be implemented should be required to be submitted for reconsideration of this application. Evendell Plat Level 3 Downstream Drainage Analysis -Haozous Engineering (8/26/2002) (Evendell application file] Channel erosion observed along the east boundary of the property at 16046 SE 142 Place, downstream of the Pipe P-11 O, has been a persistent problem over the past several years and would likely be considered a severe erosion problem. Continued bank erosion is likely at this location, with potential for reducing the capacity of the channel sections further downstream where sediment is deposited. The flooding that occurs at the adjacent residence is likely related to the reduction in channel ca aci due to sediment de osition from the eroded banks. The channel erosion observed at pipe P110 (flooding locations map_ is roughly equal to #17 on the Level I Figure 4 map originally submitted with this application. This is the Gragg property noted above. Flooding Location Map This map identified multiple sites in the Threadgill westerly drainage (natural course) that regularly flood. Specific locations identified here correspond very well to location #s 15, 16 & 17 of on the Level I Figure 4 map originally submitted with this application. We request that new Level Ill downstream analysis be required for reconsideration of this application based on the new data we submit today. Jack Case Letters, Photos and Locator Legend Packet Mr. Case has provided letters, including observations on the Level I and Level Ill Downstream reports and summarizing his years of logging data related to the stream that runs through his property, photos of the stream that runs through his and his neighbors' properties and to illustrate suboptimum traffic conditions on SE 1351 h St, and a locator map to show where and from what angle the photos were taken. The stream in Mr. Case's photos is that into which the applicant proposes to direct the easterly drainage from Threadgill. We intend to call Mr. Case as a witness later in this Hearing. Doris Yepez Packet Ms. Yepez has provided photos of the wetland in the Liberty Grove/Starwood subdivision that the applicant proposes to receive the westerly drainage from Threadgill. This wetland has virtually no vegetation and is not in any condition to function as the receiving site for the Threadgill drainage. We intend to call Ms. Yepez as a witness later in this Hearing. Page 21 of 24 •' C~RE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 • The use of native plants should be encouraged in landscaping requirements and erosion control projects, and in the restoration of stream banks, lakes, shorelines, and wetlands. KCCP E-107 The protection of lands where development would pose hazards to health, property, important ecological functions or environmental quality shall be achieved through acquisition, enhancement, incentive programs and appropriate regulations. The following natural landscape features are particularly susceptible and should be protected: c. Wetlands and their protective buffers; d. Aquatic areas, including streams, lakes, saltwater shorelines and their protective buffers; . Critical A uifer Rachar e Areas; ' KCCP E-119 ' King County shall use incentives, regulations and programs to manage its water resources (Puget Sound, rivers, streams, lakes, freshwater and marine wetlands and ground water) and to protect and enhance their multiple beneficial uses -including fish and wildlife habitat, flood and erosion control, water quality control and sediment transport, water supply, energy production, transportation, recreational opportunities and scenic beauty. Use of water resources for one u ose should, to the fullest extent racticable, reserve o ortunities for other uses. KCCP E-120 Development shall support continued ecological and hydrologic functioning of water resources and should not have a significant adverse impact on water quality or water quantity, or sediment transport and should maintain base flows, natural water level fluctuations, roundwater rechar e in Critical A uifer Recha e Areas and fish and wildlife habitat. If Threadgill's westerly drainage is not required to be directed into the new conveyance system to be constructed as part of the extension of 162"' Ave SE, then this Liberty Grove wetland must be completely upgraded to properly accommodate these new impacts, and new Drainage and Site Plans as well as Level Ill Downstream Analysis demonstrating compliance with KCCP E-163, E-107, E-119 and E-120 should be required for reconsideration of this application. High Accident Location Reports King County Accident Report Data Traffic mitigations required of Evendell, Hamilton Place, Nichols Place, Liberty Grove and Liberty Grove Contiguous/Starwood developments have proven insufficient within five years of first occupancy of these projects (some are still under construction. We intend to call a King County employee with direct knowledge of subsequent mitigation installation as a witness later in this Hearing. EvendellNicholsPlaceComplaintRecord.doc CARE members have recent, direct and heartbreaking experience with the consequences of development that is not correctly planned, actively monitored, and adequately mitigated. We offer the record of our and our neighbors' attempts to achieve justice after the damage has been done in order to fully illustrate what we hope to avoid by our participation in this Threadgill application process. We intend to call some of the King County employees identified in this exhibit as witnesses later in this Hearing. Paqe 22 of 24 CARE Response: Threadgill Subdivision Response -File No. L05P0026 January 8, 2008 • 5. Conclusions RCW 43.21 C.020(2) In order to carry out the pohcy set forth in this chapter, it is the continuing responsibility of the state of Washington and all agencies of the state to use all practicable means, consistent with other essential considerations of state policy, to improve and coordinate plans, functions, programs, and resources to the end that the state and its citizens may: (a) Fulfill the responsibilities of each generation as trustee of the environment for succeeding generations; (b) Assure for all people of Washington safe, healthful, productive, and aesthetically and culturally pleasing surroundings; (c) Attain the widest range of beneficial uses of the environment without degradation, risk to health or safety, or other undesirable and unintended conse uences; ... KCC 20 24.070(B) The examiners recommendation may be to grant or deny the application or appeal, or the examiner may recommend that the council adopt the application or appeal with such conditions, modifications and restrictions as the examiner finds necessary to carry out the applicable state laws and regulations and the regulations, including chapter 43.21C RCW ... The extension of 162nd Ave SE is a major change in our community and presents many challenges. The environmental impacts have not been inadequately considered and documented in this application, and thus the mitigations proposed are inadequate. The application was improperly deemed complete by DDES when it was not, and still is not. However, since it was accepted and subsequently has proceeded to the Public Hearing stage, we believe that the Hearing Examiner must reject this application outright as authorized by King County Code, and that is the preferred remedy we request today. Alternately, we request that this application be remanded to DDES and additional review conducted in light of the evidence we present today. In either case, we request that at the very least the following must be required: o New Application Submission Form o New Density Calculations and site plans o including calculation for required Recreational Space o reflecting the changes consequent to this MDNS requirement of additional easements o If the current site plan is not rejected for non-compliance with KCC 21 A.14.020New Density Calculations and site plans reflecting the changes consequent to reflecting the changes consequent to DDES condition requiring of easements on SE 1361 h St should be required o New site plans demonstrating that the project meets the requirements for accommodation of all forms of nonmotorized transportation o Site plan revision to reflect compliance with the School District's bus stop need o A valid Tree Inventory o New Transportation Concurrency Certificate o New notification to (including valid site plans) and comment from the School District o New Certificate of Water Availability o New Certificate of Sewer Availability o Confirmation of the specifics of the Liberty High School storrnwater facilities, and that if those facilities are determined to have been constructed as a Level Ill facility, Threadgill storrnwater facilities should also be required to be constructed at Level Ill. o New review, investigation and documentation of analysis of all drainage complaints from any parcel in or affected by either proposed course of drainage from the Threadgill site o A new Critical Areas Report o A new Level Ill Downstream Drainage Analysis demonstrating compliance with the recommendations of the Reconnaissance Report #13 Lower Cedar River Basin report and KCCP E-107, E-119 and E-120 Page 23 of 24 ' ' C~RE Response: Threadgill Subdivision Response -FIie No. L05P0026 January 8, 2008 • o The proposed fill, mitigation and buffer reduction for Wetlands A and B should be forbidden as proposed. o A new Level Ill Downstream Drainage Analysis demonstrating that negative impacts to the properties listed in Drainage Complaint 97-206 and located the same drainage course will be fully mitigated o New Mitigation Fee Calculations o Whatever the final fee calculations for the extension of 162nd Ave SE indicate, we request that these funds be pooled jointly with other such fees from all three of these applications (Threadgill, Cavalla, and Liberty Gardens), funds from the Cascade Water Alliance's Tacoma-Cascade Pipeline mitigations (please see Final Environmental Impact Statement-Tacoma-Cascade Pipeline April 26, 2007 (excerpts) we submit today), as well as funds contributed from the King County Mitigation Fee Program so that a comprehensive solution to the stormwater conveyance inadequacies so vividly illustrated in all the drainage reports can finally be addressed. o Alternatively, we request that these same sets of funds should be pooled and used to construct the most operationally functionally combination of Options recommended in the SE 144th Street Level 3 Downstream Drainage Analysis we submit to the record today. o New Traffic Impact Analyses should be required to incorporate the evidence presented in this Response for reconsideration with this application. o The Threadgill application should be held to the same standard and corresponding level of detail required by DDES staff for the Liberty Grove Contiguous, Cavalla and Liberty Gardens applications for the consideration of this application. o A new Level JI I Downstream Drainage Analysis demonstrating that the issues of "severe roadway flooding problem" on SE 144th St, the recurrent flooding in the easterly basin drainage of the Threadgill project identified in the SE 144th Street Level 3 Downstream Drainage Analysis will be fully mitigated, and that the most operationally functionally combination of Options recommended in the SE 144th Street Level 3 Downstream Drainage Analysis will be o If Threadgill's westerly drainage is not required to be directed into the new conveyance system to be constructed as part of the extension of 162nd Ave SE, then this Liberty Grove wetland must be completely upgraded to properly accommodate these new impacts, and new Drainage and Site Plans as well as Level 111 Downstream Analysis demonstrating compliance with KCCP E-163, E-107, E-119 and E-120 o New Drainage Plans which reflect mitigations and improvements to the conveyance systems which are located on private properties and proposed by the applicant to carry the easterly drainage from Threadgill The King County Hearing Examiner is authorized to grant the relief we seek, as well as the responsibility to ensure that this proposed project meets all the requirements of State and Local laws, regulations and policies. We have demonstrated the deficiencies of this application in light of these Jaws, regulations and policies. We are the Public. Our interest is in protecting our homes, preserving our neighborhoods, promoting fair and reasonable use of property to all land owners and preventing harm to our community. Thank you for your time and consideration. Page 24 of 24 ,, ··I,). v. Evendell Plat Level 3 Downstream Drainage Analysis - _, I ~iRES: FILE COPY REC'?n,~0 AUG 2 ,q 2002 LAN~IUSEL,(}i.JN I y SERVICES LOIP001 6 Submilled to: 900 Oakesdale Avenue S.W. Renton, WA 98055 Prepared by: Haowus Engineering, P.S. 9957171" Avenue SE Renton, WA 98059 Tel. (425) 235-2707 Fax (425) 254-0579 August 26, 2002 .; Drainage Complaints Drainage complaints along the downstream systems were investigated at King County Water and Land Resource Division as part of the Level I Downstream Drainage Analysis submitted with the project's preliminary technical information report (TIR)(Haozous Engineering, June 2001). Since the preliminary TIR was prepared, neighborhood comment forms, collected by C.A.R.E., have been reviewed for information about drainage-related problems in the basins. Of particular note, flooding from the ditch on the east boundary of the Evendell site has been observed by Mr. Bret Bowden, a resident at 13 814 160th A venue SE. When flooding occurs, water crosses the road and flows onto Mr. Bowden's property. Mr. Don Gregg, a resident at 16046 SE 142"d Place, has also observed portions of 160th Avenue SE inundated by flooding during the past 5 years. Methodology A hydraulic analysis was conducted for conveyance systems along both 160th Avenue SE and 1561h Avenue SE. The conveyance system along 160th Avenue SE was evaluated from the east boundary of the site for a distance of 2,300 feet. The conveyance system along 156th A venue SE was evaluated from a location due west of the site for a distance of 1,900 feet. Both systems consist of driveway culverts, pipe segments, and open channel. The model Stormshed™ was used to predict runoff rates from contributing basins and to model the hydraulics of the conveyance systems. Stormshed™ is widely applied in similar projects and has been adopted by Washington State Department of Transportation for assessing and designing highway conveyance systems. A field survey of the downstream systems was conducted by a licensed surveyor. Ditch cross sections, pipe inverts, catch basin rims, and road surface elevations were surveyed to obtain data for the Storrnshed™ hydraulic model. A summary of each structure surveyed is provided in Table I . Basin boundaries contributing to the conveyance system were based on aerial topography and the Cedar River Basin Plan. The basin boundaries were field-verified and divided into subbasins contributing to various branches of the conveyance system (Figure 2). The easterly basin was divided into seven subbasins (el -e7), ranging from I .I to 33.9 acres in size (Table 2). The westerly basin was divided into eight subbasins (wl -w8), ranging from 1.2 to 16.3 acres in size. Cover types and land uses in the subbasins were based on a 1990 aerial photograph and updated for recent development by conducting a field reconnaissance. The basins consist of mostly single-family residential land use with housing densities ranging from about 1 to 6 dwelling units per acre. Land uses and cover types are shown in Figure 3. The east basin was estimated to have a total of 124.4 acres, with 35.6 acres in forest, 20.2 in 2 .·\ pasture, and 68.7 acres in single-family residential land use (Table 3). The west basin was estimated to have a total of 48.3 acres, with 6.5 acres in forest, 7 .0 in pasture, and 33.4 acres in single-family residential land use, and 1.4 acres occupied by a church. Based on King County Soil Survey (U.S. Department of Agriculture, 1973) soil types in the basins consist of Aldcrwood soils. The Santa Barbara Urban Hydrograph (SBUH) model was used to model the runoff from each of the subbasins contributing to the conveyance systems. Curve numbers for the subbasins were based on the weighted averages of the various land uses in the watershed (Table 4). Hydrographs for the 2-, 10-, 25-, 50-, and 100-year storms were routed through the Stormshed™ hydraulic model of the conveyance systems to detennine flooding locations and their approximate return periods. The Evendell site and other contributing areas in the basins were modeled under their existing land use conditions. Travel paths for each subbasin were based on aerial topography. The type of flow, flow length, and slope used to calculate time-of-concentrations are summarized in Table 5. Rainfall amounts of2.0, 3.0, 3.5, 3.75, and 4.0 inches were used for the 2-, 10-, 25-, 50-, and 100-year storms design storms in the SBUH model. Modeling Results Details of each subbasin modeled in Stormshed are presented in Appendix A.I for the easterly basin and in Appendix A.2 for the westerly basin. Model results for routing the design storm hydrographs through the drainage networks are presented in Tables B. I through B.12 of Appendix B. Table 6 presents a summary of flow rates at key locations in each of the conveyance systems. A summary of predicted flooding, for all surveyed structures, including open channels, is provided in Table B.6 for the easterly basin and in Table B.12 for the westerly basin. The locations and return periods of flooding related to pipes and culverts are identified in Figure 4. Many of the driveway culverts and pipes along 160th A venue SE flood at a return period of 2-years (Table B.6 and Figure 4). Several reaches of ditch also overtop at this return period, likely as a result of constrictions in the pipe capacities. Modeling results are consistent with drainage complaints from residents along this reach of the drainage course. Similar modeling results were obtained for the westerly drainage course, where several culverts and catch basins were predicted to overtop at 2-year or 10-year return periods (Table B.12 and Figure 4). Conclusions Several flooding locations with return periods of2°years were identified in the downstream conveyance systems. Flooding in the east basin that overtops and inundates 160th Avenue SE is considered a severe road flooding problem by the King County 3 ·1 Surface Water Drainage Marmal. Residential structures have been flooded at 14928 160th Avenue SE and at 16046 SE 142"d Place. If the finished space or the electrical/heating components of these residential structures were flooded in the past, the flooding would be classified as a severe problem. Otherwise, flooding that occurs at these residences is considered a nuisance problem. Channel erosion observed along the east boundary of the property at 16046 SE 142nd Place, downstream from Pipe P-110, has been a persistent problem over the past several years and would likely be considered a severe erosion problem. Continued bank erosion is likely at this location, with potential for reducing the capacity of channel sections further downstream where sediment is deposited. The flooding that occurs at the adjacent residence is likely related to the reduction in channel capacity due to sediment deposition from the eroded banks. Based on modeling results and information available, flooding problems in the westerly basin would likely be classified as nuisance problems by the King County Surface Water Drainage Manual (1998). We found no documentation indicating that 156th Avenue SE or residential structures along the westerly drainage course have flooded in the past. However, a drainage complaint (Complaint No. 97-0318) related to flooding due to a plugged culvert, was not available for review (Haozous Engineering, June 2001 ). Proposed Mitigations Level 2 RID standards are currently being proposed for new development in the westerly basin of the Evendell Plat. No additional flow control or other mitigations are therefore required in this basin to reduce project impacts to nuisance flooding problems. Level 2 RID standards are also currently being proposed for new development in the easterly basin of the Evendell Plat. With severe flooding and severe erosion problems located in the downstream drainage course, additional measures to mitigate drainage impacts could be required. For the severe road flooding problem along 160,. Avenue SE either of the following mitigations could be required: • Providing Level 3 detention in the easterly basin, OR • Upgrading the downstream conveyance system along 160th Avenue SE to eliminate road flooding. This would likely entail replacing driveway culverts P-117 and P- 116 on the west side of 160,. Avenue SE, cross culvert P-115, and pipes P-114 and P-113 on the east side ofl60th Avenue SE (Figure 4). For the severe erosion problem along the east boundary of the property at 16046 SE 142nd Place, the Level 2 RID standards provide the mitigation required by code. Other types of mitigations to reduce erosion at this location, such as bank stabilization in the eroded section of channel or Level J RID standards, can be imposed through the King County Surface Water Drainage Manual under certain circumstances. It is our opinion that either stabilizing the eroding section of channel or the use of Level J RID standards would mitigate project-related drainage impacts that occur at this location. 4 ·l If you have questions regarding these analyses or need additional documentation, please do not hesitate to call me. Sincerely, Edward McCarthy, Ph.D. P.E. Hydrologist 5 9957 17/~ Avenue SE fax (425) 254-0579 August 26, 2002 Mr. Michael Romano /Engln@@ring, Renton, WA 98059 (425) 135-1707 Centurion Development Services 22617 8th Drive SE Bothell, WA 98021 Re: Evendell Plat -Level 3 Downstream Drainage Analysis DOES File No. Dear Mr. Romano: ff'. !J. This letter report documents the methods and resnlts of a Level 3 Downstream Drainage Analysis requested by DOES for the Evendell Plat. Separate analyses were conducted for the two drainage courses from the Evendell site. Project Description The Evendell Plat is a proposed residential development located within the Renton Highlands area of unincorporated King County (Figure I). The proposal for development includes building single-family dwellings on approximately 12 acres (Haozous Engineering, June 2001 ). Road improvements along SE 136th Street are also proposed. Level 2 RID standards are being proposed for the onsite stonnwater facility as is required by the King County Flow Application Maps and recommended by Lower Cedar River Basin and Nonpoint Action Plan. Site Description The site is located within the Orting Hills subbasin of the Cedar River watershed (King County Department of Natural Resources, 1999). The site is located east of 156th Avenue SE and is bordered by SE 136th Street on the north and by 160th A venue SE on the east. Cover types on the site include a single-family residence, pasture, and forest. A Class 2 wetland bas been identified in the northeast portion of the site. The site consists of two basins with most of the project area draining to the easterly basin. The easterly basin drains to a conveyance system along 160th Avenue SE. The westerly basin drains to a conveyance system along I 56th A venue SE. Both downstream drainage courses eventually discharge to an unclassified tributary of the Cedar River (King County Department of Parks, Planning, and Resources, 1990). References Haozous Engineering, June 15, 2001. Evendell Plat -Preliminary Technical Information Report. Renton, Wash. King County Department of Natural Resources, 1998. King County Surface Water Design Manual. Seattle. King County Department ofNatural Resources, 1997. Lawer Cedar River Basin and Nonpoint Pollution Action Plan. Seattle. King County Department of Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio. Seattle. U.S. Department of Agriculture, Soil Conservation Service, 1973. Soil Survey of King County Area, Washington. Seattle. 6 Table I. Sumary of Surveyed Structures in Downstream System Reach ID Reach Pipe Dia. Manning's Length UpstrIE DwnstIE Slope Type (IN) n (FT) (FT) (FT) (%) East Basin D-110 X-Section 0.035 48 408.54 407.59 1.99 D-111 X-Section 0.035 58 409.57 408.54 1.78 D-112 X-Section 0.035 20 411.25 409.57 8.57 D-113 X-Section 0.035 12 411.86 411.25 5.28 D-Jl4 X-Scction 0.035 48 412.96 411.86 2.31 P-110 Circular 24 0.010 60 413.6 412.96 1.06 D-115 X-Section 0.035 3 414.27 413.6 · 25.24 D-116 X-Section 0.035 33 415. l 414.27 2.48 D-117 X-Section 0.035 24 415.34 415.1 1.01 D-J18 X-Section 0.035 25 417.07 415.34 7.01 D-119 X-Section 0.035 48 419.77 417.07 5.61 D-120 X-Section 0.035 79 420.05 419.77 0.35 P-111 Circular 18 0.013 29 419.3 420.05 -2.56 D-121 X-Section 0.035 6 421.94 419.3 45.68 D-122 X-Section 0.035 24 422.17 421.94 0.96 P-112 Circnlar 12 0.013 85 423.42 422.17 1.47 D-123 X-Section 0.035 43 424.16 423.42 1.73 D-124 X-Section 0.065 90 424.6 424.16 0.49 D-125 X-Section 0.065 107 426.13 424.6 1.43 D-126 X-Section 0.065 48 428.17 426.13 4.27 D-127 X-Section 0.035 79 429.74 428.17 1.99 D-128 X-Section 0.035 56 431.36 429.74 2.87 P-113 Circular 18 0.01 124 434.95 431.36 2.91 D-129 X-Section 0.035 12 434.81 434.95 -1.21 D-130 X-Section 0.035 61 436.28 434.81 2.40 D-131 X-Section 0.035 66 439.l 436.28 4.30 P-114 Circular 24 0.024 21 439.59 439.1 2.37 D-132 X-Section 0.035 10 440.26 439.59 7.02 P-115 Circular 12 0.013 45 441.31 439.59 3.78 D-133 X-Section 0.035 2 441.15 441.31 -7.30 D-133A X-Section 0.035 35 442.14 441.15 2.80 D-134 X-Section 0.035 50 443.4 442.14 2.53 D-135 X-Section 0.035 106 444.67 443.4 1.20 D-136 X-Section 0.035 54 445.89 444.67 2.25 P-116 Circular 18 0.024 28 446.34 445.89 1.62 D-137 X-Section 0.035 3 446.6 446.34 10.15 D-138 X-Section 0.035 88 448.4 446.6 2.04 D-139 X-Section 0.035 106 451.13 448.4 2.58 D-140 X-Section 0.035 55 452.3 451.13 2.15 P-117 Circular 12 0.013 18 452.9 452.3 3.39 D-141 X-Section 0.035 3 452.65 452.9 -9.42 D-142 X-Section 0.035 102 454.76 452.65 2.07 D-143 X-Section 0.035 160 459.46 454.76 2.93 D-144 X-Section 0.035 103 462.79 459.46 3.24 D-145 X-Section 0.035 100 466.72 462.79 3.92 ' Table 1 (continued) Reach JD Reach Pipe Dia. Manning's Length UpstrIE Dwnst IE Slope Type (IN) n (FT) (Ff) (FT) (%) West Basin P-001 Circular 12 0.013 113 378.62 372.66 5.27 D-001 X-Section 0.035 3 379.22 378.62 20.00 D-002 X-Section 0.035 114 381.68 379.22 2.16 D-003 X-Section 0.035 153 388.9 381.68 4.72 D-004 X-Section 0.035 157 397.4 388.9 5.41 D-005 X-Section 0.035 2 396.77 397.4 -31.50 P-002 Circular 12 0.013 25 397.51 396.77 2.96· D-006 X-Section 0.035 3 398.49 397.51 32.67 D-007 X-Section 0.035 35 399.58 398.49 3.11 P-003 Circular 12 0.013 19 400.17 399.58 3.11 D-008 X-Section 0.035 2 400.4 400.17 11.50 D-009 X-Section 0.035 36 400.91 400.4 1.42 P-004 Circular 12 0.013 59 403.71 400.91 4.75 P-005 Circular 12 0.013 9 404.21 403.51 7.78 P-006 Circular 12 0.013 42 406.09 404.26 4.36 P-007 Circular 12 0.013 150 411.17 406.34 3.22 P-008 Circular 12 0.013 157 417.58 411. 77 3.70 P-008A Circular 12 0.013 28 418.1 417.58 1.86 P-009 Circular 12 0.013 142 427.25 420.75 4.58 P-010 Circular 12 0.013 86 431.9 427.35 5.29 P-011 Circular 12 0.013 62 434.34 432 3.77 P-012 Circular 12 0.013 33 435.68 434.39 3.91 D-010 X-Section 0.035 3 436.07 435.68 13.00 D-011 X-Section 0.035 48 438.87 436.07 5.83 D-012 X-Section 0.035 53 442.78 438.87 7.38 P-013 Circular 12 0.013 19 444.46 442.78 8.84 D-014 X-Section 0.035 3 444.63 444.46 5.67 D-015 X-Section 0.035 43 446.52 444.63 4.40 P-014 Circular 12 0.013 23 447.67 446.52 5.00 D-016 X-Section 0.035 3 448.08 447.67 13.67 D-017 X-Section 0.035 57 450.3 448.08 3.89 P-015 Circular 12 0.013 22 451.33 450.3 4.68 D-018 X-Section 0.035 3 451.83 451.33 16.67 D-019 X-Section 0.035 52 454.6 451.83 5.33 P-016 Circular 12 0.013 34 457.55 454.6 8.68 D-020 X-Section 0.035 3 457.71 457.55 5.33 D-021 X-Section 0.035 107 465.05 457.71 6.86 ' ., Table 2. Summary of Existing Basin Cover Types by Subbasin Curve Number= Subbasin East Basin el e2 e3 e4 e5 e6 e7 Site -East Subtotal West Basin wl w2 w3 w4 w5 w6 w7 w8 Site - West Subtotal 81 0 85 0 Till-forest Till-pasture (AC) (AC) -5.8 6.0 5.2 -1.7 -- 4.0 1.8 14.9 3.5 1.8 - 8.9 2.2 35.6 20.2 -- -0.7 -- -- -- 0.8 - 1.6 - 3.8 4.9 0.4 1.4 6.6 7.0 98 0 86 0 98 0 Cover Type Wetland Till-grass Imperv (AC) (AC) (AC) 12.0 1.9 15.6 7.0 0.7 0.1 0.9 0.2 12.3 5.4 9.8 2.3 -- 0.4 -0.1 0.4 51.4 16.9 2.3 0.6 13.8 1.8 1.0 0.2 2.7 0.5 1.8 0.4 1.8 1.3 3.8 2.4 0.4 0.0 --0.1 -27.6 7.2 Total (AC) 19.7 33.9 2.4 I. I 23.5 30.4 1.8 11.6 124.5 2.9 16.3 1.2 3.2 2.2 3.8 7.8 9.1 1.9 48.4 ·I Table 4. Curve Numbers for Subbasins Suhhasin Pervious Pervious Imperv CN (AC) (AC) East Basin el 85.7 17.8 1.9 e2 84.7 26.9 7.0 e3 85.3 2.3 0.1 e4 86.0 0.9 0.2 e5 84.8 18.1 5.4 e6 83.2 28.1 2.3 e7 81.0 1.8 - Site -.East 81.8 I I.I 0.5 West Basin wl 86.0 2.3 0.6 w2 86.0 14.5 1.8 w3 86.0 1.0 0.2 w4 86.0 2.7 0.5 w5 86.0 1.8 0.4 w6 84.5 2.5 1.3 w7 84.5 5.4 2.4 w8 83.4 9.0 0.0 Site - West 84.0 1.8 0.1 Table 5. Travel Path Distances and Slopes for Pervious Land Areas I ·. / ~#~i{tf<Iw \ Delta -'·. Sh~:j~!aw , :;!{t!f\"~~:<ilope ·• ···· Channel Fl~w f · Delta " : Slop~ . Subbasi~ · ·.• 'Diifqnce ·. Elev. Distance Elev. Slope -\·-;.;.:,;-f:i/,_i. :·'. .. · .. · "(tf71. ·.·. (FT) .(FT/FI) (FT) .. • (FT)) : •.· " (i/T!FT) (FT) '(FT) (FT/FT) East Basin el 300.0 5.0 0.017 1,484.0 20.0 0.013 950.0 10.0 0.011 e2 300.0 5.0 0.017 922.0 15.0 0.016 1,824,0 18.0 0.010 e3 300.0 5.0 0.017 264.0 3.0 0.011 106.0 3.0 0.028 e4 300.0 5.0 0.017 200.0 4.0 0.020 e5 300.0 8.0 0.027 1,248.0 23.0 0.018 705.0 10.0 0.014 e6 300.0 3.0 0.010 1,777.0 35.0 0.020 e7 300.0 3.0 0.010 Site -East 300.0 3.0 0.010 876.0 13.0 0.015 West Basin wl 2,610.0 70.0 0.027 w2 300.0 5.0 0.017 585.0 70.0 0.120 w3 300.0 32.0 0.107 272.0 13.0 0.048 w4 300.0 10.0 0.033 292.0 22.0 0.075 w5 300.0 30.0 0 JOO 322.0 22.0 0.068 w6 300.0 2.0 0.007 613.0 40.0 0.065 w7 300.0 20.0 0.067 655.0 40.0 0.061 w8 300.0 20.0 0.067 1,020.0 70.0 0.069 Site - West 210.0 10.0 0.048 .... Table 6. Peak Flow Rates at Selected Locations. Storm Return Period Location 2-Year JO-year 25-Year 50-Year JOO-Year (CFS) (CFS) (CFS) (CFS) (CFS) East Basin P-110 12.0 24.5 31.6 35.3 38.9 P-111 12.1 24.9 32.0 35.6 39.4 P-112 9.9 20.0 25.5 28.3 31.2 P-113 10.2 20.3 25.9 28.7 31.6 P-114 10.2 20.4 25.9 28.8 31.7 P-115 7.4 15.2 19.4 21.6 23.8 P-116 7.3 14.9 19.1 21.2 23.4 West Basin P-001 6.8 13.7 17.5 19.4 21.2 P-002 6.2 12.2 15.4 17.0 18.6 P-006 4.8 9.6 12.2 13.5 14.7 P-008A 4.1 8.4 10.8 11.9 13.l P-009 3.8 7.7 9.8 10.9 11.9 P-013 3.2 6.7 8.5 9.4 10.4 P-015 3.0 6.2 8.0 8.8 9.1 P-016 2.8 5.7 7.3 8.1 8.9 Note: Flow rates are those predicted by Stormshed using the SBUH method. ., SOURCE: USGS 7.5 x 15 Minute Series -Renton, Washington SCALE: 1 :25 000 HTI.E Figure 1. Vicinity Map PAGE 1-5 01/03/01 Appendix A. Stormshed Model Input/Output Design Storm Rainfall Amounts Return Rainfall Period Amount (YRS) (IN) 2 2.00 10 3.00 25 3.50 50 3.75 100 4.00 ' •\ Appendix A.1. Subbasin Summary -East Basin Drainage Area: e-001 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervious 17.8000 ac 85.70 Impervious 1.9000 ac 98.00 Total 19.7000 ac Pervious CN Data: Subbasin e-00 I Perv Impervious CN Data: Subbasin el Imperv Pervious TC Data: Flow type: Description: Sheet el sheet Shallow e I shallow Channel e I channel Impervious TC Data: Flow type: Description: Fixed None Entered 85.70 98.00 Loss Method: SCS CN Number SCS Abs: lntv: 0.20 10.00 min TC 0.98 hrs 0.17hrs 17.8000 ac 1.9000 ac Length: Slope: 300.00 ft 1. 70% 1484.00 ft 1.50% 950.00 ft 1.10%, Length: Slope: 0.00 ft 0.00% Coeff: Travel Time 0.1500 31.85 min 11.0000 18.36 min 17.0000 8.88 min Coeff: Travel Time 10.0000 10.00 min Drainage Area: e-002 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 26.9000 ac Impervious 7.0000 ac Total 33.9000 ac Pervious CN Data: Subbasin e-002 Perv Impervious CN Data: Subbasin el Imperv Pervious TC Data: Flow type: Description: Sheet e2 sheet Shallow e2 shallow Channel e2 channel Impervious TC Data: Flow type: Description: Fixed None Entered CN 84.70 98.00 84.70 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 1.01 hrs 0.17 hrs 26.9000 ac 7.0000 ac Length: Slope: 300.00 ft 1.70% 922.00 ft 1.60% 1824.00 ft 1.00% Length: Slope: 0.00 ft 0.00% Coeff: Travel Time 0.1500 31.85 min 11. 0000 l l. 04 min 17.0000 17.88 min Coeff: Travel Time 10.0000 10.00 min -l Drainage Area: e-003 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 2.3000 ac 85.30 0.60 hrs Impervious 0.1000 ac 98.00 0.17hrs Total 2.4000 ac Pervious CN Data: Subbasin e-003 Perv 85.30 2.3000 ac Impervious CN Data: Subbasin e3 Imperv 98.00 0.1000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet e3 sheet 300.00 ft 1.70% 0.1500 31.85 min Shallow e3 shallow 264 00 ft 1.10% 11.0000 3.81 min Channel e3 channel 106.00 ft 2.80% 17.0000 0.62 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00"/o 10.0000 10.00 min -l Drainage Area: e-004 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs lntv: 10.00 min Area CN TC Pervious 0.9000 ac 86.00 0.55 hrs Impervious 0.2000 ac 98.00 0.17 hrs Total 1.1000 ac Pervious CN Data: Subbasin e-004 Perv 86.00 0.9000 ac Impervious CN Data: Subbasin e4 Imperv 98.00 0.2000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coelf: Travel Time Sheet e4 sheet 300.00 ft 1.70% 0.1500 31.85 min Channel e4 channel 200.00 ft 2.00% 17.0000 1.39 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min ., Drainage Area: e-005 HydMethod: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 18.1000 ac Impervious 5.4000 ac Total 23.5000 ac Pervious CN Data: Subbasin e-005 Perv Impervious CN Data: Subbasin e5 Imperv Pervious TC Data: Flow type: Description: Sheet e5 sheet Shallow e5 shallow Sheet e5 channel Impervious TC Data: Flow type: Description: Fixed None Entered CN 84.80 98.00 84.80 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 lntv: 10.00 min TC 1.81 hrs 0.17 hrs 18.1000 ac 5.4000 ac Length: Slope: 300.00 ft 2.70% 1248 00 ft 1.80% 705.00 ft 1.40% Length: Slope: 0 00 ft 0.00% Coeff: Travel Time 0.1500 26.47 min 11.0000 14.09 min 0.1500 68.19 min Coeff: Travel Time 10.0000 10.00 min ' Drainage Area: e-006 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 28.1000 ac Impervious 2.3000 ac Total 30.4000 ac Pervious CN Data: Subbasin e-006 Perv Impervious CN Data: Subbasin eS Imperv Pervious TC Data: CN 83.20 98.00 83.20 98.00 Flow type: Description: Length: Sheet e6 sheet Shallow e6 shallow Impervious TC Data: Flow type: Description: Fixed None Entered Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 1.35 hrs 0.17hrs 28.1000 ac 2.3000 ac Slope: Coeff: Travel Time 300.00 ft 1.00% 1777.00 ft 2.00% Length: Slope: 0.00 ft 0.00% 0.1500 39.38 min S 0000 41.88 min Coeff: Travel Time 10.0000 10.00 min Drainage Area: e-007 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 1. 8000 ac Impervious 0.0000 ac Total 1.8000 ac Pervious CN Data: Subbasin e-007 Perv Pervious TC Data: Flow type: Description: Sheet e7 sheet CN 81.00 98.00 81.00 Loss Method: SCS CN Number SCS Abs: Intv: TC 1.44 hTs 0.00 hTs 1.8000 ac 0.20 10.00 min Length: Slope: 300.00 ft 1.00%, Coeff: 0.4000 Travel Time 86.31 min ·l Drainage Arca: ex_ east Hyd Method: SBUHHyd Loss Method: · SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs lntv: 10.00 min Area CN TC Pervious 11.1000 ac 81.80 2.lOhrs Impervious 0.5000 ac 98.00 0.17hrs Total 11.6000 ac Pervious CN Data: Subbasin ex east Perv 81.80 11.1000 ac Impervious CN Data: Subbasin ex_ east Imperv 98.00 0.5000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet ex east sheet 300.00 ft 1.00% 0.4000 86.31 min Shallow ex east shallow 876.00 ft 1.50% 3.0000 39.74 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0 00 ft 0.00% 10.0000 10.00min Appendix A.2. Subbasin Summary -West Basin Drainage Area: w-001 Hyd Method: SBUH Hyd PeakFactor: 484.00 Storm Dur: 24.00 hrs Area Pervious 2.3000 ac Impervious 0.6000 ac Total 2.9000 ac Pervious CN Data: Subbasin w 1 Perv Impervious CN Data: Subbasin wl Pervious TC Data: Flow type: Description: Time Channel wl Impervious TC Data: Flow type: Description: Time Fixed wl CN 86.00 98.00 86.00 98.00 Loss Method: SCS CN Number SCSAbs: 0.20 Intv: 10.00 min TC 0.26 hrs 0.17 hrs 2.3000 ac 0.6000 ac Length: Slope: Coeff: Travel 2610.00 ft 2.70% 17.0000 15.57 min Length: Slope: Coeff: Travel 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: w-002 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 14.5000 ac 86.00 0.57 hrs Impervious 1.8000 ac 98.00 0.17 hrs Total 16.3000 ac Pervious CN Data: Subbasin w2 Perv 86.00 14.5000 ac Impervious CN Data: Subbasin w2 Imperv 98.00 1.8000ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet None Entered 300.00 ft 1.70"/o 0.1500 31.85 min Shallow None Entered 585.00 ft 12.00"/o 11.0000 2.56 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: w-003 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00min Area CN TC Pervious 1.0000 ac 86.00 0.27 hrs Impervious 0.2000 ac 98.00 0.17hrs Total 1.2000 ac Pervious CN Data: Subbasin w3 Perv 86.00 1.0000 ac Impervious CN Data: Subbasin w3 Imperv 98.00 0.2000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w3 sheet 300.00 ft 10.70% 0.1500 15.26 min Channel w3 channel 272.00 ft 4.80% 17.0000 1.22 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min ·1 Drainage Area: w-004 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 2.7000 ac 86.00 0.43 hrs Impervious 0.5000 ac 98.00 O.I7hrs Total 3.2000 ac Pervious CN Data: Subbasin w4 Perv 86.00 2.7000 ac Impervious CN Data: Subbasin w4 98.00 0.5000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w4 sheet 300.00 ft 3.30% 0.1500 24.43 min Shallow w4 shallow 292.00 ft 7.50% 11.0000 1.62 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min Drainage Area; w-005 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervi~ms 1.8000 ac 86.00 Impervious 0.4000 ac 98.00 Total 2.2000 ac Pervious CN Data: Subbasin w5 Perv 86.00 Impervious CN Data: SubbasinwS 98.00 Pervious TC Data: Flow type: Description: Length: Sheet w5 sheet Shallow w5 shallow Impervious TC Data: Flow type: Description: Time Fixed None Entered Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 0.29 hrs 0.17 hrs 1.8000 ac 0.4000 ac Slope: Coeff: Travel Time 300.00 ft 10.00% 0.1500 15.68 min 322.00 ft 6.80% 11.0000 1.87 min Length: Slope: Coeff: Travel 0.00 ft 0.00% 10, 0000 10. 00 min "Drainage Area: w-006 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24 00 hrs Intv: 10.00 min Area CN TC Pervious 2.5000 ac 84.50 0.82 hrs Impervious 1.3000 ac 98.00 0.17hrs Total 3.8000 ac Pervious CN Data: Subbasin w6 Perv 84.50 2.5000 ac Impervious CN Data: Subbasinw6 98.00 1.3000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w6 sheet 300.00 ft 0.700/o 0.1500 45.42 min Shallow w6 shallow 613.00 ft 6.50% 11.0000 3.64min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min , ., Drainage Area: w-008 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 9.0000 ac Impervious 0.0000 ac Total 9.0000 ac Pervious CN Data: Subbasin w8 Perv Pervious TC Data: Flow type: Description: Time Sheet w8 sheet Shallow w8 shallow Impervious TC Data: Flow type: Description: Time Fixed None Entered CN 83.40 0.00 83.40 Loss Method: SCS CN Number SCS Abs Intv: 0.20 10.00 min TC 0.79 hrs O.I7hrs 9.0000 ac Length: Slope: 300.00 ft 6.700/o 1020.00 ft 6.90% Length: Slope: 0.00 ft 0.00% Coeff: Travel 0.4000 40.33 min 9.0000 7.19 min Coeff Travel 10.0000 10.00 min ' •\ · Drainage Area: ex_ west Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 1.8000 ac Impervious 0.1000 ac Total 1.9000 ac Pervious CN Data: Subbasin ex west Perv Impervious CN Data: Subbasin ex west Irnperv Pervious TC Data: Flow type: Description: Time Sheet ex west sheet Impervious TC Data: Flow type: Description: Time Fixed wl Loss Method: SCS CN Number SCS Abs: 0.20 lntv: 10.00 min CN TC 84.00 0.3.8 hrs 98.00 0.17 hrs 84.00 1.8000 ac 98.00 0.1000 ac Length: Slope: Coeff: Travel 210.00 ft 4.80% 0.2400 23.02 min Length: Slope: Coeff: Travel 0.00 ft 0.00% 10.0000 10.00 min 'Appendix B. Hydrograph Routing ' ., . Table B.1. Hydrograph Routing -East Basin -2-Year Storm ROUTEHYD [] THRU [Existing East) USING TYPE1A AND [2 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac els els ratio ft fl/s fl/s ------------ D-Dum2 19.7 2.1303 122.33 0.02 0.3312 X-Sect 3.0688 ·-e-001 D-Dum1 53.6 6.625 122.33 0.05 0.5728 X-Sect 4.4532 --·-e-002 D-145 53.6 6.5953 121.12 0.05 0.5744 X-Sect 4.4169 ---- D-144 53.6 .6.5642 117.92 0.06 0.6659 X-Sect 4.3432 ---- D-143 53.6 6.5478 122.41 0.05 0.6381 X-Sect 4.0213 --- D-142 53.6 6.5467 82.3869 0.08 0.6881 X-Sect 3.5759 - D-141 53.6 6.5465 10.3949 0.63 1.6141 X-Sect 1.1146 - P-117 65.2 7.0246 6.5804 1.07 0.9037 12" Diam 9.4073 8.3784 ex_east D-140 65.2 7.0224 124.5 0.06 0.4782 X-Sect 3.1305-- D-139 65.2 7.018 117 .81 0.06 0.4685 X-Sect 3.4675 -- D-138 65.2 7.013 94.8108 0.07 0.6314 X-Sect 3.4413 -- D-137 67.6 7.2807 279 0.03 0.4113 X-Sect 5.3323 --e-003 P-116 67.6 7.2787 7.2535 1 1.2342 18" Diam 4.6787 4.1046 D-136 67.6 7.2745 61.7242 0.12 0.6832 X-Sect 3.5858- D-135 67.6 7.2645 66.6905 0.11 0.7836 X-Sect 2.9393 --- D-134 67.6 7.2596 70.9939 0.1 0.5719 X-Sect 3.6244 -- D-133A 67.6 7.2557 93.7984 0.08 0.6719 X-Sect 3.6325 - D-133 67.6 7.2549 26.6671 0.27 1.4156 X-Sect 1.1841 - P-115 68.7 7.4254 6.9473 1.07 0.9067 12" Diam 9.9203 8.8456 e-004 D-132 68.7 7.4237 226.87 0.03 0.5902 X-Sect 5.7063-- P-114 92.2 10.2247 18.9199 0.54 1.0474 24" Diam 6.1392 6.0224 e-005 D-131 92.2 10.2216 338.51 0.03 0.5631 X-Sect 4.9185- D-130 92.2 10.2183 33.2703 0.31 0.8395 X-Sect 4.3224- D-129 92.2 10.2164 8.6723 1.18 -1 X-Sect 1.178 --- P-113 92.2 10.212 23.5738 0.43 0.6902 18" Diam 12.8615 13.34 D-128 92.2 10.2081 266.41 0.04 0.6392 X-Secl 4.3565- D-127 92.2 10.1973 1354.11 0.01 0.6263 X-Sect 2.0863 -- D-126 92.2 10.1853 491.48 0.02 0.3323 X-Sect 1.4977 --·-- D-125 92.2 10.132 3470.27 0 0.3539 X-Sect 0.8642 --- D-124 92.2 9.9841 549.84 0.02 0.2991 X-Sect 0.5983 -- D-123 92.2 9.9643 3827.85 0 0.4105 X-Sect 1.946- P-112 92.2 9.9216 4.3371 2.29 -1 12" Diam 2.2876 5.5221 D-122 92.2 9.9128 50.2681 0.2 0.904 X-Sect 2.771 -- D-121 122.6 12.0698 594.02 0.02 0.2893 X-Sect 10.2968 -----e-006 P-111 122.6 12.0648 15.3148 0.79 1.0036 18" Diam 9.6013 8.6664 D-120 122.6 12.0245 18.2879 0.66 1.4658 X-Sect 2.1936 -- D-119 122.6 12.0107 17.5281 0.69 0.6067 X-Sect 4.6997 -- D-118 122.6 12.0027 179.94 0.07 0.4436 X-Sect 5.2531 -- D-117 122.6 11.9926 61.1492 0.2 1.0638 X-Sect 2.9017 -- D-116 122.6 11.9823 27.9865 0.43 1.096 X-Sect 4.2499-- D-115 122.6 11.9814 78.2241 0.15 1.2007 X-Sect 4.2155- P-110 122.6 11.972 30.6525 0.39 0.868 24" Diam 9.156 9.757 D-114 122.6 11.9572 47.75 0.25 1.1715 X-Sect 4.2164 --- D-113 124.4 12.0112 319.76 0.04 0.6751 X-Sect 5.8978 ---e-007 D-112 124.4 12.0055 1134.16 0.01 0.5548 X-Sect 5.7484- D-111 124.4 11.9853 413.21 0.03 0. 7639 X-Sect 3.7479 -- D-110-124.4 11.9689 241.55 0.05 o:698 X-Sect 3.9096 ·-- Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl fl fl fl fl N-110 408.288 N-111 N-110 409.238 -na---na----na--409.238 411.92 N-112 N-111 409.9703 -na----na---na--409.9703 414.13 N-113 N-112 411.6608 -na----na---na--411.6607 415.64 N-114 N-113 412.5349 -na--na---na--412.5349 415.67 N-115 N-114 414.1314 --na---na--na--414.18 414.08 N-116 N-115 415.5033 -na---na--na-415.5033 416.5 N-117 N-116 415.5562 -na--na--na-415.5562 416.39 N-118 N-117 416.3861 -na--na--na-416.3861 416.39 N-119 N-118 416.626 -na--na--na--416.71 416.61 N-120 N-119 418.44 --na--na--na--418.24 418.14 N-121 N-120 420.9399 --na--na--na-420.43 420.33 N-122 N-121 421.5157 -na---na--na--421.5157 422.69 N-123 N-122 422.9861 --na--na---na-422.9861 423.31 N-124 N-123 425.626 -na--na--na-423.41 423.31 N-125 N-124 423.64 -na--na--na--423.64 424.05 N-126 N-125 433.8967 -na--na----na-424.9 424.8 N-127 N-126 425.6399 -na--na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427 .6098 -na--na--na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.4499 -na--na--na-432.45 432.79 N-133 N-132 437 .2623 --na--na--na-436.5 436.4 N-134 N-133 436.5119 -na--na--na-436.03 435.93 N-135 N-134 437.4999 -na--na--na-437.57 437.47 N-136 N-135 440.3899 --na---na--na-440.25 440.15 N-137 N-136 441.418 -na---na--na-441.418 442.1 N-137A N-137 442.088 -na---na---na--441.99 441.89 N-138 N-137A 445.5185 -na--na---na-442.9 442.8 N-139 N-138 442.9019 -na--na--na-442.9 442.8 N-140 N-139 443.8899 --na--na--na-443.14 443.04 N-141 N-140 444 .3999 -na---na--na-444.3999 444.84 N-142 N-141 445.6699 -na--na--na--445.6699 446.11 N-143 N-142 446.8898 -na--na--na-446.8898 447.71 N-144 N-143 448.3436 -na---na--na-448.2 448.1 N-145 N-144 448.4599 -na---na--na--447.84 447.74 N-146 N-145 449.6399 -na--na--na-449.6399 449.84 N-147 N-146 452.3699 -na--na--na-452.3698 452.71 N-148 N-147 453.5398 -na--na--na-453.5398 453.89 N-149 N-148 456.7368 -na--na--na-454.3 454.2 N-150 N-149 454.303 -na--na--na-454.3029 454.65 N-151 N-150 456.4129 -na--na--na-455.87 455.77 N-152 N-151 460 .5699 -na--na--na-460.56 460.46 N-153 N-152 463.89 --na---na---na--463.89 464.17 N-154 N-153 467.8199 -na--na--na-467.44 467.34 , ., Table fl.2. Hydrograph Routing -East Basin -10-Year Storm ROUTEHYD D THRU [Existing East] USING TYPE1A AND [10 yr] NOTZERO ACTUAL Reach Area Flow Full Q %Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s -------- D-Dum2 19.7 4.4884 122.33 0.04 0.4719 X-Sect 3.935 ----e-001 D-Dum1 53.6 13.1058 122.33 0.11 0.81 X-Sect 5.5304 -e-002 D-145 53.6 13.1051 121.12 0.11 0.8142 X-Sect 5.4927 --- D-144 53.6 13.1036 117.92 0.11 0.9649 X-Sect 5.2679 --- D-143 53.6 13.1 122.41 0.11 0.9032 X-Sect 4.856 --- D-142 53.6 13.0953 82.3869 0.16 0.9821 X-Sect 4.3102- D-141 53.6 13.0948 10.3949 1.26 -1 X-Sect 1.2597 - P-117 65.2 14.3238 6.5804 2.18 -1 12" Diam 2.1767 8.3784 ex_east D-140 65.2 14.3181 124.5 0.12 0.6926 X-Sect 3.9913- D-139 65.2 14.3076 117.81 0.12 0.6891 X-Sect 4.3262- D-138 65.2 14.2973 94.8108 0.15 0.9065 X-Sect 4.2086 --- D-137 67.6 14.8971 279 0.05 0.5622 X-Sect 6.5644-e-003 ' P-116 67.6 14.8875 7.2535 2.05 -1 18" Diam 2.0525 4.1046 D-136 67.6 14.8791 61.7242 0.24 0.9641 X-Sect 4.5155- D-135 67.6 14.86 66.6905 0.22 1.1209 X-Sect 3.6062- D-134 67.6 14.8509 70.9939 0.21 0.8189 X-Sect 4.472- D-133A 67.6 14.8437 93.7984 0.16 0.899 X-Sect 4.4767 --- D-133 67.6 14.8424 26.6671 0.56 1.9795 X-Sect 1.4503- P-115 68.7 15.1643 6.9473 2.18 -1 12" Diam 2.1828 8.8456 e-004 D-132 68.7 15.1617 226.87 0.07 0.8315 X-Sect 7.0313- P-114 92.2 20.3817 18.9199 1.08 -1 24" Diam 1.0773 6.0224 e-005 D-131 922 20.3728 338.51 0.06 0.8183 X-Sect 6.0985- D-130 92.2 20.3642 33.2703 0.61 1 2093 X-Sect 52653 - D-129 92.2 20.3511 8.6723 2.35 -1 X-Sect 2.3467- P-113 92.2 20.3415 23.5738 0.86 1.0749 18" Diam 15.0091 13.34 D-128 92.2 20.3328 266.41 0.08 0.9398 X-Sect 5.4109 -- D-127 92.2 20.3088 1354.11 0.01 0. 7502 X-Sect 2.4283- D-126 92.2 20.2866 491.48 0.04 0.428 X-Sect 1.9106 - D-125 92.2 20.1873 3470.27 0.01 0.4582 X-Sect 1.0267 -- D-124 92.2 20.03 549.84 0.04 0.4223 X-Sect 0.7679- D-123 92.2 19.9985 3827.85 0.01 0.5331 X-Sect 2.3162- P-112 92.2 19.9587 4.3371 4.6 -1 12" Diam 4.6019 5.5221 D-122 92.2 19.9456 50.2681 0.4 1 .2487 X-Sect 3.3192- D-121 122.6 24.93 594.02 0.04 0.4161 X-Sect 13.223 -e-006 P-111 122.6 24.8832 15.3148 1.62 -1 18' Diam 1.6248 8.6664 D-120 122.6 24.6416 18.2879 1.35 -1 X-Sect 1.3474 - D-119 122.6 24.5438 17.5281 1.4 -1 X-Sect 1.4002 -- D-118 122.6 24.5308 179.94 0.14 0.6339 X-Sect 6.562- D-117 122.6 24.5144 61.1492 0.4 1.4223 X-Sect 3.6544- D-116 122.6 24.4971 27.9865 0.88 1.4271 X-Sect 5.1474 - D-115 122.6 24.4955 78.2241 0.31 1.657 4 X-Sect 5.1522- P-110 122.6 24.4801 30.6525 0.8 1.3515 24" Diam 10.8367 9.757 D-114 122.6 24.4557 47.75 0.51 1.5399 X-Sect 5.2816 - D-113 124.4 24.6393 319.76 0.08 1.0057 X-Sect 7.2971 -e-007 D-112 124.4 24.6301 1134.16 0.02 0.742 X-Sect 7.4221 - D-111 124.4 24.5979 413.21 0.06 1.1252 X-Sect 4.6448 -- D-110' 124.4 24.5719 241.55 0.1 1.0455 X-Sect 4.8977 ----- Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl fl fl ft fl N-110 408.6355 N-111 N-110 409.5854 -na---na---na-409.5854 411.92 N-112 N-111 410.6952 -na---na--na--410.6952 414.13 N-113 N-112 412.3751 -na--na---na-412.3751 415.64 N-114 N-113 412.985 --na----na---na--412.985 415.67 N-115 N-114 414.5504 -na--na--na-414.18 414.08 N-116 N-115 417.346 --na--na--na-416.6 416.5 N-117 N-116 416.6529 --na--na--na-416.49 416.39 N-118 N-117 417.3199 --na---na--na-416.49 416.39 N-119 N-118 416.7623 -na--na--na-416.71 416.61 N-120 N-119 418.4399 -na---na--na-418.24 418.14 N-121 N-120 420.9399 --na---na---na-420.43 420.33 N-122 N-121 421.3322 --na--na--na-421.3322 422.69 N-123 N-122 427.5867 -na--na--na-423.41 423.31 N-124 N-123 426.0499 -na--na--na-423.41 423.31 N-125 N-124 423.6399 -na---na--na-423.64 424.05 N-126 N-125 465.1461 -na--na--na-424.9 424.8 N-127 N-126 425.6399 -na--na---na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427.6098 -na--na---na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.4499 -na--na--na-432.45 432.79 N-133 N-132 441.2068 --na--na---na-436.5 436.4 N-134 N-133 436.5119 -na--na--na-436.03 435.93 N-135 N-134 437.4999 -na--na--na-437.57 437.47 N-136 N-135 440.3899 -na--na--na-440.25 440.15 N-137 N-136 442.9103 -na---na----na-442.2 442.1 N-137A N-137 442.87 -na--na---na-441.99 441.89 N-138 N-137A 458.8658 -na--na---na-442.9 442.8 N-139 N-138 443.1294 -na--na--na-442.9 442.8 N-140 N-139 443.89 -na--na--na--443.14 443.04 N-141 N-140 444.3999 --na--na--na-444.3999 444.84 N-142 N-141 445.7908 -na---na--na-445.7908 446.11 N-143 N-142 447.0108 -na--na--na-447.0107 447.71 N-144 N-143 451.3791 -na---na---na--448.2 448.1 N-145 N-144 448.46 -na---na--na-447.84 447.74 N-146 N-145 449.6399 -na--na---na-449.6399 449.84 N-147 N-146 452.3698 -na---na--na-452.3698 452.71 N-148 N-147 453.5397 -na--na--na-453.5397 453.89 N-149 N-148 464.129 -na--na---na-454.3 454.2 N-150 N-149 454.3029 -na--na----na-454.3029 454.65 N-151 N-150 456.4128 -na--na---na-455.87 455.77 N-152 N-151 460.5699 -na--na--na-460.56 460.46 N-153 N-152 463.8899 -na---na--na-463.89 464.17 N-154 N-153 467.8199 -na--na--na-467.44 467.34 ·I Table lil.3. Hydrograph Routing -East Basin -25-Year Stonn ROUTEHYD D THRU [Existing East) USING TYPE1A AND [25 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac els els ratio fl fl/s fl/s ------- D-Dum2 19.7 5.7736 122.33 0.05 0.5347 X-Sect 4.2649 ----e-001 D-Dum1 53.6 16.6641 122.33 0.14 0.9204 X-Sect 5.9522 --e-002 D-145 53.6 16.6623 121.12 0.14 0.9253 X-Sect 5.911 ----- D-144 53.6 16.6597 117.92 0.14 1.095 X-Sect 5.6189 -- D-143 53.6 16.6543 122.41 0.14 1.0158 X-Sect 5.1748 -- 0-142 53.6 16.6481 82.3869 0.2 1.1029 X-Sect 4.6242 -- D-141 53.6 16.6444 10.3949 1.6 -1 X-Sect 1.6012 - P-117 65.2 18.3188 6.5804 2.78 -1 12" Diam 2.7838 8.3784 ex_east D-140 65.2 18.3118 124.5 0.15 0.7894 X-Sect 4.3271 -- D-139 65.2 18_2992 117.81 0.16 0. 786 X-Sect 4.6556- D-138 65.2 18.2868 94.8108 0.19 1.0247 X-Sect 4.5015 -- D-137 67.6 19.0686 279 0.07 0.6269 X-Sect 7.0354-e-003 P-116 67.6 19.0592 7.2535 2.63 -1 18" Diam 2.6276 4.1046 D-138 67.6 19.0493 61.7242 0.31 1.0913 X-Sect 4.8719- D-135 67.6 19.0273 66.6905 0.29 1.2672 X-Sect 3.86-- D-134 67.6 19.0167 70.9939 0.27 0.926 X-Sect 4.7959- D-133A 67.6 19.0082 93.7984 0.2 0.9908 X-Sect 4.8691- D-133 67.6 19.0069 26.6671 0.71 2.2289 X-Sect 1.5584- P-115 68.7 19.4194 6.9473 2.8 -1 12" Diam 2.7952 8.8456 e-004 0-132 68.7 19.4163 226.87 0.09 0.9372 X-Sect 7.5367- P-114 92.2 25.943 18.9199 1.37 -1 24" Diam 1.3712 6.0224 e-005 D-131 92.2 25.9323 338.51 0.08 0.9321 X-Sect 6.5545- D-130 92.2 25.9219 33.2703 0.78 1.3721 X-Sect 5.6512 - D-129 92.2 25.9106 8.6723 2.99 -1 X-Sect 2.9877- P-113 92.2 25.8992 23.5738 1.1 -1 18" Diam 1.0986 13.34 D-128 92.2 25.8888 266.41 0.1 1.076 X-Sect 5.818 --- D-127 92.2 25.8608 1354.11 0.02 0.8003 X-Sect 2.5676- D-126 92.2 25.8358 491.48 0.05 0.4713 X-Sect 2.076 --- D-125 92.2 25.7224 3470.27 0.01 0.5018 X-Sect 1.0908 -- D-124 92.2 25.5489 549.84 0.05 0.478-X-Sect 0.836- D-123 92.2 25.5134 3827.85 0.01 0.584 X-Sect 2.4616- P-112 92.2 25.4763 4.3371 5.87 -1 12" Diam 5.8741 5.5221 D-122 92.2 25.4617 50.2681 0.51 1.3879 X-Sect 3.5601 - D-121 122.6 32.0486 594.02 0.05 0.4735 X-Sect 14.376-e-006 P-111 122.6 32.0049 15.3148 2.09 -1 18" Diam 2.0898 8.6664 D-120 122.6 31.7866 18.2879 1.74 -1 X-Sect 1.7381 - D-119 122.6 31.6961 17.5281 1.81 -1 X-Sect 1.8083 -- D-118 122.6 31.6812 179;94 0.16 0.7203 X-Sect 7.0637- D-117 122.6 31.6627 61.1492 0.52 1.5908 X-Sect 3.9591 - D-116 122.6 31.6418 27.9865 1.13 -1 X-Sect 1.1306 - D-115 122.6 31.64 78.2241 0.4 1. 866 X-Sect 5.5186- P-110 122.6 31.6228 30.6525 1.03 1.7027 24" Diam 11.096 9.757 D-114 122.6 31.5955 47.75 0.66 1. 7176 X-Sect 5.6991 - D-113 124.4 31.8576 319.76 0.1 1.1584 X-Sect 7.8462-e-007 D-112 124.4 31.8471 1134.16 0.03 0.8307 X-Sect 8.1092 - D-111 124.4 31.8116 413.21 0.08 1.2906 X-Sect 4.9987 -- D-110 124.4 31.7828 241.55 Reh App Loss Head Fr Node To Node ft ft N-110 408.797 N-111 N-110 409.747 -na-- N-112 N-111 410.8606 --na-- N-113 N-112 412.5405 -na- N-114 N-113 413.1504 --na- N-115 N-114 414.8065 --na- N-116 N-115 418.962 --na- N-117 N-116 416.6529 -na-- N-118 N-117 417.3199 -na- N-119 N-118 416.9307 -na- N-120 N-119 418.4399 --na- N-121 N-120 420.9399 -na- N-122 N-121 421.5229 --na- N-123 N-122 431.8698 -na- N-124 N-123 426.0499 --na- N-125 N-124 423.64 -na- N-126 N-125 491.2671 -na- N-127 N-126 425.6399 -na- N-128 N-127 426.0798 -na- N-129 N-128 427.6098 -na- N-130 N-129 429.6497 -na- N-131 N-130 430.9699 -na- N-132 N-131 432.45-na- N-133 N-132 437 .2202 --na- N-134 N-133 436.5119 -na- N-135 N-134 437.85 --na- N-136 N-135 440.39 -na- N-137 N-136 444.033 -na- N-137A N-137 442.8699 --na- N-138 N-137A 469.665 --na- N-139 N-138 443.3789 -na- N-140 N-139 443. 89 --na- N-141 N-140 444.3999 -na- N-142 N-141 445.9371 --na- N-143 N-142 447.157 -na- N-144 N-143 453. 928 -na-- N-145 N-144 448.46 -na- N-146 N-145 449.6399 -na-- N-147 N-146 452.3699 -na- N-148 N-147 453.5398 -na- N-149 N-148 470.8597 -na- N-150 N-149 454.3029 -na- N-151 N-150 456.4129 -na- N-152 N-151 460.5699 -na- N-153 N-152 463.8981 -na-- N-154 N-153 467 .828 -na-- 0.13 1 .207 X-Sect Bend June! HW Loss Loss Elev ft ft ft --na---na--409.747 -na---na--410.8606 -na----na-412.5405 --na---na-413.1505 -na--na-414.18 --na--na-416.6 -na--na-416.49 -na--na-416.49 -na--na-416.71 --na---na-418.24 -na----na-420.43 --na---na-421.5229 -na---na--423.41 -na---na-423.41 -na---na-423.64 -na--na--424.9 -na--na-425.6399 -na--na-426.0798 -na--na-427.6097 -na--na-429.4 -na--na-430.83 -na--na-432.45 -na---na-436.5 -na--na-436.03 -na--na-437.57 -na--na-440.25 -na----na-442.2 -na---na--441.99 --na---na-442.9 -na--na-442.9 -na---na--443.14 -na---na-444.3999 -na---na-445.9371 -na---na-447.157 -na---na-448.2 -na--na-447.84 -na--na-449.6399 -na--na-452.3699 -na----na-453.5398 -na--na-454.3 -na---na-454.3029 --na--na-455.87 -na--na-460.56 --na--na-463.8981 -na--na-467.44 5.2894 ----- Max El/ Rim El fl 411.92 414.13 415.64 415.67 414.08 416.5 416.39 416.39 416.61 418.14 420.33 422.69 423.31 423.31 424.05 424.8 426.02 426.52 428.27 429.3 430.73 432.79 436.4 435.93 437.47 440.15 442.1 441.89 442.8 442.8 443.04 444.84 446.11 447.71 448.1 447.74 449.84 452.71 453.89 454.2 454.65 455.77 460.46 464.17 467.34 ' ., Table B.4. Hydrograph Routing -East Basin -50-Year Storm ROUTEHYD O THRU [Existing East) USING TYPE1A AND [50 yr) NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac els els ratio ft 11/s 11/s ----- D-Dum2 19.7 6.4328 122.33 0.05 0.5644 X-Sect 4.4125 ----e-001 D-Dum1 53.6 18.4875 122.33 0.15 0.9737 X-Sect 6.1401 ----e-002 D-145 53.6 18.4851 121.12 0.15 0.9789 X-Sect 6.0973 - D-144 53.6 18.482 117.92 0.16 1.1561 X-Sect 5.7757 -- D-143 53.6 18.4757 122.41 0.15 1. 0682 X-Sect 5.3178 - D-142 53.6 18.4689 82.3869 0.22 1.16 X-Sect 4.7688 --- D-141 53.6 18.4652 10.3949 1.78 -1 X-Sect 1.7764 - P-117 65.2 20.3744 6.5804 3.1 -1 12• Diam 3.0962 8.3784 ex_east D-140 65.2 20.3667 124.5 0.16 0.8355 X-Sect 4.4786- D-139 65.2 20.3531 117.81 0.17 0.8317 X-Sect 4.8035 -- D-138 65.2 20.3398 94.8108 0.21 1.0799 X-Sect 4.6329 -- D-137 67.6 21.2149 279 0.08 0.6572 X-Sect 7.2468 -e-003 P-116 67.6 21.2056 7.2535 2.92 -1 18" Diam 2.9235 4.1046 D-136 67.6 21.1949 61.7242 0.34 1.152 X-Sect 5.0314 - D-135 67.6 21.1716 66.6905 0.32 1.3357 X-Sect 3.9737- D-134 67.6 21.1602 70.9939 0.3 0.9762 X-Sect 4.9411 --- D-133A 67.6 21.1511 93.7984 0.23 1.035 X-Sect 5.0466 -- 0-133 67.6 21.1496 26.6671 0.79 2.3487 X-Sect 1.6064 - P-115 68.7 21.6082 6.9473 3.11 -1 12" Diam 3.1103 8.8456 e-004 D-132 68.7 21.605 226.87 0.1 0.9869 X-Sect 7.7628- P-114 92.2 28.7909 18.9199 1.52 -1 24" Diam 1.5217 6.0224 e-005 D-131 92.2 28.7784 338.51 0.09 0.9857 X-Sect 6.7585- 0-130 92.2 28.7663 33.2703 0.86 1.4508 X-Sect 5.8219- D-129 92.2 28.7555 8.6723 3.32 -1 X-Sect 3.3158 -- P-113 92.2 28.7428 23.5738 1.22 -1 18" Diam 1.2193 13.34 D-128 92.2 28.731 266.41 0.11 1.1405 X-Sect 5.9997- D-127 92.2 28.699 1354.11 0.02 0.8231 X-Sect 2.6309- D-126 92.2 28.6712 491.48 0.06 0.4918 X-Sect 2.1506 --- D-125 92.2 28.5445 3470.27 0.01 0.5218 X-Sect 1.1196 - D-124 92.2 28.3566 549.84 0.05 0.5043 X-Sect 0.8666- D-123 92.2 28.3183 3827.85 0.01 0.6073 X-Sect 2.5267- P-112 92.2 28.2813 4.3371 6.52 -1 12" Diam 6.5208 5.5221 D-122 92.2 28.2656 50.2681 0.56 1.4497 X-Sect 3.6834- D-121 122.6 35.6853 594.02 0.06 0.5006 X-Sect 14.8923 --e-006 P-111 122.6 35.6419 15.3148 2.33 -1 18" Diam 2.3273 8.6664 D-120 122.6 35.4329 18.2879 1.94 -1 X-Sect 1.9375 - D-119 122.6 35.3437 17.5281 2.02 -1 X-Sect 2.0164 - D-118 122.6 35.3278 179.94 0.2 0. 7605 X-Sect 7.315 -- D-117 122.6 35.308 61.1492 0.58 1 . 6707 X-Sect 4.0938- D-116 122.6 35.2852 27.9865 1.26 -1 X-Sect 1.2608 - D-115 122.6 35.2833 78.2241 0.45 1.9632 X-Sect 5.68- P-110 122.6 35.2651 30.6525 1.15 -1 24" Diam 1.1505 9.757 D-114 122.6 35.2359 47.75 0.74 1.8022 X-Sect 5.8823- D-113 124.4 35.5397 319.76 0.11 1.2299 X-Sect 8.0881 -e-007 D-112 124.4 35.5284 1134.16 0.03 0.8726 X-Sect 8.4163- D-111 124.4 35.4908 413.21 0.09 1.3677 X-Sect 5.1548- :; D-110' 124.4 35.4602 241.55 0.15 1.2828 X-Sect 5.4622- Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl ft ft ft fl fl N-110 408.8728 N-111 N-110 409.8228 --na----na----na-409.8228 411.92 N-112 N-111 410.9377 --na---na----na-410.9377 414.13 N-113 N-112 412.6176 -na---na--na--412.6176 415.64 N-114 N-113 413.2275 --na---na--na-413.2275 415.67 N-115 N-114 414.9305 -na--na---na-414.18 414.08 N-116 N-115 415.8377 -na--na---na-415.8377 416.5 N-117 N-116 416.2331 -na---na--na-416.2331 416.39 N-118 N-117 417.0631 -na--na--na-416.49 416.39 N-119 N-118 417.0166 -na---na--na-416.71 416.61 N-120 N-119 418.4399 -na---na----na-418.24 418.14 N-121 N-120 420.9399 -na---na---na-420.43 420.33 N-122 N-121 421.6109 -na--na--na-421.6109 422.69 N-123 N-122 434.4431 -na---na---na-423.41 423.31 N-124 N-123 426.0499 -na--na--na-423.41 423.31 N-125 N-124 423.6399 -na--na--na-423.6399 424.05 N-126 N-125 506.9789 -na--na--na-424.9 424.8 N-127 N-126 425.6399 -na--na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427.6098 -na--na--na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.5004 -na--na--na-432.5004 432.79 N-133 N-132 438.2302 -na--na---na-436.5 436.4 N-134 N-133 436.5119 -na----na--na-436.03 435.93 N-135 N-134 437.85 -na--na---na-437.57 437.47 N-136 N-135 440.3899 -na--na--na-440.25 440.15 N-137 N-136 444.7122 -na---na--na-442.2 442.1 N-137A N-137 442.8699 -na--na--na-441.99 441.89 N-138 N-137A 476.2553 --na---na--na--442.9 442.8 N-139 N-138 443.4986 -na--na--na-442.9 442.8 N-140 N-139 443.8899 -na--na--na-443.14 443.04 N-141 N-140 444.3999 --na---na---na-444.3999 444.84 N-142 N-141 446.0057 --na--na--na-446.0057 446.11 N-143 N-142 447.2256 -na----na---na-447.2256 447.71 N-144 N-143 455 .4835 -na----na---na-448.2 448.1 N-145 N-144 448.46 -na---na--na-447.84 447.74 N-146 N-145 449.6399 -na--na--na-449.6399 449.84 N-147 N-146 452.3699 -na--na--na-452.3698 452.71 N-148 N-147 453.5398 -na---na--na-453.5398 453.89 N-149 N-148 474.9647 --na--na---na-454.3 454.2 N-150 N-149 454.3029 --na--na--na-454.3029 454.65 N-151 N-150 456.4129 -na--na---na-455.87 455.77 N-152 N-151 460.5836 -na--na--na-460.56 460.46 N-153 N-152 463.9726 -na--na--na-463.9726 464.17 N-154 N-153 467.9025 -na----na--na-467.44 467.34 Table 8.5. Hydrograph Routing -East Basin -1 DO-Year Stonn ROUTEHYD [] THRU [Existing East] USING TYPE1A AND [100 yr] NOTZERO ACTUAL Reach Area Flow FullQ % Full nDepth Size nVel Nel CBasin I Hyd ac cfs cfs ratio fl fl/s fl/s ----------- D-Dum2 19.7 7.1007 122.33 0.06 0.5932 X-Sect 4.5504-e-001 D-Dum1 53.6 20.334 122.33 0.17 1 . 0256 X-Sect 6.3154 --e-002 D-145 53.6 20.3311 121.12 0.17 1.0311 X-Sect 6.2711 - D-144 53.6 20.3274 117.92 0.17 1.2148 X-Sect 5.9225 ---- D-143 53.6 20.3204 122.41 0.17 1.1183 X-Sect 5.4519 -- D-142 53.6 20.3129 82.3869 0.25 1.2157 X-Sect 4.9037 --- D-141 53.6 20.3094 10.3949 1.95 -1 X-Sect 1.9538 - P-117 65.2 22.46 6.5804 3.41 -1 12" Diam 3.4132 8.3784 ex_east D-140 65.2 22.4518 124.5 0.18 0.8802 X-Sect 4.6208- D-139 65.2 22.4372 117.81 0.19 0.8757 X-Sect 4.9419- D-138 65.2 22.4229 94.8108 0.24 1 .1329 X-Sect 4.756-- D-137 67.6 23.3927 279 0.08 0.6862 X-Sect 7.4448 -e-003 P-116 67.6 23.3835 7.2535 3.22 -1 18" Diam 3.2238 4.1046 D-136 67.6 23.3721 61.7242 0.38 1.2109 X-Sect 5.1805 - D-135 67.6 23.3475 66.6905 0.35 1.4016 X-Sect 4.08- D-134 67.6 23.3353 70.9939 0.33 1.0244 X-Sect 5.0771 - D-133A 67.6 23.3254 93.7984 0.25 1.0782 X-Sect 5.2133 - D-133 67.6 23.3239 26.6671 0.87 2.4653 X-Sect 1.6511 - P-115 68.7 23.829 6.9473 3.43 -1 12" Diam 3.43 8.8456 e-004 D-132 68.7 23.8256 226.87 0.11 1.0347 X-Sect 7.9743- P-114 92.2 31.6894 18.9199 1.67 -1 24" Diam 1.6749 6.0224 e-005 D-131 92.2 31.6761 338.51 0.09 1.0378 X-Sect 6.9502- D-130 92.2 31.6628 33.2703 0.95 1.5281 X-Sect 5.9813- D-129 92.2 31.6529 8.6723 3.65 -1 X-Sect 3.6499- P-113 92.2 31.6395 23.5738 1.34 -1 18" Diam 1.3421 13.34 D-128 92.2 31.627 266.41 0.12 1.2034 X-Sect 6.1704 -- D-127 92.2 31.5932 1354.11 0.02 0.8449 X-Sect 2.6909 -- D-126 92.2 31.5642 491.48 0.06 0.5117 X-Sect 2.2214 --- D-125 92.2 31.4314 3470.27 0.01 0.541 X-Sect 1.1469-- D-124 92.2 31.2367 549.84 0.06 0.5301 X-Sect 0.8959- D-123 92.2 31.1967 3827.85 0.01 0.6298 X-Sect 2.5886- P-112 92.2 31.1607 4.3371 7.18 -1 12" Diam 7.1847 5.5221 D-122 92.2 31.1444 50.2681 0.62 1 . 5106 X-Sect 3.8005- D-121 122.6 39.4139 594.02 0.07 0.527 X-Sect 15.3819-e-006 P-111 122.6 39.3717 15.3148 2.57 -1 18" Diam 2.5708 8.6664 D-120 122.6 39.1738 18.2879 2.14 -1 X-Sect 2.1421 - D-119 122.6 39.0873 17.5281 2.23 -1 X-Sect 2.23- D-118 122.6 39.0705 179.94 0.22 0. 7996 X-Sect 7.5336 -- D-117 122.6 39.0498 61.1492 0.64 1. 7 492 X-Sect 4.2208- D-116 122.6 38.9434 27.9865 1.39 -1 X-Sect 1.3915 - D-115 122.6 38.9414 78.2241 0.5 2.0557 X-Sect 5.829- P-110 122.6 38.9219 30.6525 1.27 -1 24" Diam 1.2698 9.757 D-114 122.6 38.8904 47.75 0.81 1.8838 X-Sect 6.0508 -- D-113 124.4 39.2371 319.76 0.12 1.298 X-Sect 8.3113 --e-007 D-112 124.4 39.225 1134.16 0.03 0.9129 X-Sect 8.7019 -- D-111 124.4 39.1846 413.21 0.09 1.4411 X-Sect 5.2991 -- D-110· 124.4 39.1518 241.55 0.16 1.3552 X-Sect 5.6219 ---- Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl ft fl fl ft N-110 408.9452 N-111 N-110 409.8951 --na----na---na-409.8951 411.92 N-112 N-111 411.0111 -na----na---na-411.0111 414.13 N-113 N-112 412.691 --na----na----na-412.691 415.64 N-114 N-113 413.3009 --na----na--na--413.3009 415.67 N-115 N-114 415.03 --na----na--na-414. 18 414.08 N-116 N-115 416.0292 -na--na--na-416.0292 416.5 N-117 N-116 416.3256 --na--na--na-416.3256 416.39 N-118 N-117 417.1555 -na--na--na-416.49 416.39 N-119 N-118 417.1629 -na--na--na-416.71 416.61 N-120 N-119 418.4399 --na---na--na-418.24 418.14 N-121 N-120 420.9399 -na----na--na-420.43 420.33 N-122 N-121 421.696 -na---na--na-421.696 422.69 N-123 N-122 437.3544 -na---na--na--423.41 423.31 N-124 N-123 426.0499 -na----na--na-423.41 423.31 N-125 N-124 423.6805 -na--na--na--423.6805 424.05 N-126 N-125 524.8533 -na--na--na-424.9 424.8 N-127 N-126 425.6399 -na--na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427.6098 -na--na---na-427.6097 428.27 N-130 N-129 429.6497 -na--na---na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.5633 -na--na--na-432.5633 432.79 N-133 N-132 439.3671 -na--na--na-436.5 436.4 N-134 N-133 436.5119 -na--na--na-436.03 435.93 N-135 N-134 437.85 -na--na--na-437.57 437.47 N-136 N-135 440.3899 -na--na--na-440.25 440.15 N-137 N-136 445.4762 -na--na---na--442.2 442.1 N-137A N-137 442.8699 --na---na--na-441.99 441.89 N-138 N-137A 483.6605 -na--na--na-442.9 442.8 N-139 N-138 443.6152 -na--na--na-442.9 442.8 N-140 N-139 443.8899 --na--na---na-443.14 443.04 N-141 N-140 444.4243 -na----na---na-444.4243 444.84 N-142 N-141 446.0716 -na---na--na-446.0716 446.11 N-143 N-142 447.2915 -na--na--na-447.2915 447.71 N-144 N-143 457.2313 -na--na---na-448.2 448.1 N-145 N-144 448 .4599 -na--na--na-447.84 447.74 N-146 N-145 449.6399 -na--na---na-449.6399 449.84 N-147 N-146 452.3698 -na--na--na-452.3698 452.71 N-148 N-147 . 453.5398 -na--na--na-453.5398 453.89 N-149 N-148 479.5756 -na--na--na-454.3 454.2 N-150 N-149 454.3031 --na---na--na-454.3031 454.65 N-151 N-150 456.413 -na--na--na-455.87 455.77 N-152 N-151 460.6481 -na---na---na-460.56 460.46 N-153 N-152 464.0445 -na--na--na-464.0445 464.17 N-154 N-153 467.9954 -na--na--na-467.44 467.34 ' ., Table B.6. Hydrograph Routing -East Basin -Summary Table 2-Year 10-Year 25-Year SO-Year 100-Year Freeboard Freeboard Freeboard Freeboard Freeboard Reach ID From Node To Node (FT) (FT) (FT) (FT) (FT) N-110 D-110 N-111 N-110 2.68 2.33 2.17 2.10 2.02 D-111 N-112 N-111 4.16 3.43 3.27 3.19 3.12 D-112 N-113 N-112 3.98 3.26 3.10 3.02 2.95 D-113 N-114 N-113 3.14 2.69 2.52 2.44 2.37 D-114 N-115 N-114 Overtop Overtop Overtop Overtop Overtop P-110 N-116 N-115 1.00 Overtop Overtop 0.66 0.47 D-115 N-117 N-116 0.83 Overtop Overtop 0.16 0.06 D-116 N-118 N-117 0.00 Overtop Overtop Overtop Overtop D-117 N-119 N-118 Overtop Overtop Overtop Overtop Overtop D-118 N-120 N-119 Overtop Overtop Overtop Overtop Overtop D-119 N-121 N-120 Overtop Overtop Overtop Overtop Overtop D-120 N-1~ N-121 1.17 1.36 1.17 1.08 0.99 P-111 N-123 N-122 0.32 Overtop Overtop Overtop Overtop D-121 N-124 N-123 Overtop Overtop Overtop Overtop Overtop D-122 N-125 N-124 0.41 0.41 0.41 0.41 0.37 P-112 N-126 N-125 Overtop Overtop Overtop Overtop Overtop D-123 N-127 N-126 0.38 0.38 0.38 0.38 0.38 D-124 N-128 N-127 0.44 0.44 0.44 0.44 0.44 D-125 N-129 N-128 0.66 0.66 0.66 0.66 0.66 D-126 N-130 N-129 Overtop Overtop Overtop Overtop Overtop D-127 N-131 N-130 Overtop Overtop Overtop Overtop Overtop D-128 N-132 N-131 0.34 0.34 0.34 0.29 0.23 P-113 N-133 N-132 Overtop Overtop Overtop Overtop Overtop D-129 N-134 N-133 Overtop Overtop Overtop Overtop Overtop D-130 N-135 N-134 Overtop Overtop Overtop Overtop Overtop D-131 N-136 N-135 Overtop Overtop Overtop Overtop Overtop P-114 N-137 N-136 0.68 Overtop Overtop Overtop Overtop D-132 N-137A N-137 Overtop Overtop Overtop Overtop Overtop P-115 N-138 N-137A Overtop Overtop Overtop · Overtop Overtop D-133 N-139 N-138 Overtop Overtop Overtop Overtop Overtop D-133A N-140 N-139 Overtop Overtop Overtop Overtop Overtop D-134 N-141 N-140 0.44 0.44 0.44 0.44 0.42 D-135 N-142 N-141 0.44 0.32 0.17 0.10 0.04 D-136 N-143 N-142 0.82 0.70 0.55 0.48 0.42 P-116 N-144 N-143 Overtop Overtop Overtop Overtop Overtop D-137 N-145 N-144 Overtop Overtop Overtop Overtop Overtop D-138 N-146 N-145 0.20 0.20 0.20 0.20 0.20 D-139 N-147 N-146 0.34 0.34 0.34 0.34 0.34 D-140 N-148 N-147 0.35 0.35 0.35 0.35 0.35 P-117 N-149 N-148 Overtop Overtop Overtop Overtop Overtop D-141 N-150 N-149 0.35 0.35 0.35 0.35 0.35 D-142 N-151 N-150 Overtop Overtop Overtop Overtop Overtop D-143 N-152 N-151 Overtop Overtop Overtop Overtop Overtop D-144 N-153 N-152 0.28 0.28 0.27 0.20 0.13 D-145 N-154 N-153 Overtop Overtop Overtop Overtop Overtop . Table 's.7. Hydrograph Routing -West Basin -2-Year Stonn ROUTEHYD U THRU [Existing West] USING TYPE1 A AND [2 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ---------- D-021 2.9 0.5767 215.99 0 0.3321 X-Sect 3.0535 --w-001 D-020 2.9 0.5766 75.0242 0.01 0.3244 X-Sect 2.7143 --- P-016 19.2 2.8102 10.5228 0.27 0.3529 12" Diam 11.3425 13.398 w-002 D-019 19.2 2.8096 212.76 0.01 0.6667 X-Sect 4.1816 ---- D-018 21.1 3.0333 251.93 0.01 0.2382 X-Sect 5.8108 -ex_west P-015 21.1 3.0325 7.7298 0.39 0.4351 12" Diam 9.2462. 9.8418 D-017 21.1 3.0318 138.18 0.02 0.3561 X-Sect 3.5277- D-016 21.1 3.0316 452.04 0.01 0.254 X-Sect 5.0894 -- P-014 22.3 3.2439 7.9881 0.41 0.4436 12" Diam 9.6423 10.1708 w-003 D-015 22.3 3.2432 160.64 0.02 0.451 X-Sect 3.7541 -- D-014 22.3 3.2429 200 0.02 0.6317 X-Sect 4.3238 -- P-013 22.3 3.2423 10.6228 0.31 0.3791 12" Diam 11.8787 13.5253 D-012 22.3 3.2413 290.67 0.01 0.6234 X-Sect 4.8101 -- D-011 22.3 3.2403 320.43 0.01 0.3609 X-Sect 4.0339 - D-010 25.5 3.7564 1040.88 0 0.5771 X-Sect 6.1421 --w-004 P-012 25.5 3.7551 7.0631 0.53 0.5186 12" Diam 9.1309 8.9931 P-011 25.5 3.7536 6.9402 0.54 0.5239 12" Diam 9.0097 8.8365 P-010 25.5 3.7521 8.217 0.46 0.4742 12" Diam 10.2249 10.4623 P-009 25.5 3.7507 7.6431 0.49 0.4945 12" Diam 9.6859 9.7315 P-008A 27.7 4.1444 4.8684 0.85 0.709 12" Diam 6.9597 6.1986 w-005 P-008 31.5 4.8063 6.8722 0.7 0.6161 12" Diam 9.4657 8.75 w-006 P-007 31.5 4.8057 6.4104 0.75 0.6459 12" Diam 8.9569 8.162 P-006 31.5 4.8039 7.4569 0.64 0.5839 12" Diam 10.0875 9.4945 P-005 39.3 6.248 9.9629 0.63 0.574 12" Diam 13.3954 12.6852 w-007 P-004 39.3 6.2406 7.7824 0.8 0.6778 12" Diam 11.0133 9.9088 D-009 39.3 6.2233 93.993 0.07 0.6278 X-Sect 2.79- D-008 39.3 6.2231 112.96 0.06 0.414 X-Sect 6.2056- P-003 39.3 6.2205 6.2952 0.99 0.8091 12" Diam 9.1373 8.0153 D-007 39.3 6.2079 107.57 0.06 0.5256 X-Sect 3.8357 --- D-006 39.3 6.2077 964.56 0.01 0.3936 X-Sect 8.1166 - P-002 39.3 6.204 6.1462 1.01 0.8284 12" Diam 8.9179 7.8256 D-005 39.3 6.2035 --0 0.915 X-Sect 2.1497 -- D-004 39.3 6.1864 44.3354 0.14 0.5256 X-Sect 4.8288 -- D-003 39.3 6.1853 313.41 0.02 0.5341 X-Sect 4.3358 - D-002 39.3 6.1799 770.99 0.01 0.6454 X-Sect 1.5651 - D-001 39.3 6.1797 146.32 0.04 0.4209 X-Sect 7.1705 -- P-001 48.3 6.7994 8.2043 0.83 0.6946 12" Diam 11.6778 10.4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.6321 N-002 N-001 382.2466 -na--na--na-380.5 380.4 N-003 N-002 381.0999 -na--na--na-380.43 380.33 N-004 N-003 382. 8899 -na---na--na-382.3 382.2 N-005 N-004 389.8769 -na---na--na-389.8769 390.25 .; N-006' N-005 398.3768 -na---na----na-398.3768 398.68 N-007 N-006 397.7699 --na---na---na--397.7699 398.68 N-008 N-007 400.6486 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.4899 -na---na---na-400.32 400.22 N-012 N-011 403.3211 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na---na----na-401.9 401.8 N-015 N-014 402.4099 --na---na---na-402.4099 402.6 N-016 N-015 406.8691 0.9827 0.0089 -----405.8952 406.01 N-017 N-016 407.6445 0.5809 0.0075 ------406.41 406.31 N-018 N-017 408.2272 0.5814 0.0023 ----407.6481 408.14 N-019 N-018 411.1539 -411.1539 413.72 N-019A N-019 419.722 0.4324 0.0032 ---419.2928 420.68 N-020 N-019A 420.102 ---420.102 422.5 N-021 N-020 428.8048 0.3544 0.0039-428.4543 429.85 N-022 N-021 431.8735 1.2605 0.0049 -----430.6179 434 N-023 N-022 435.9002 0.355 0.0013 ---435.5465 436.59 N-024 N-023 437.2402 -na---na---na-437.2402 438.2 N-025 N-024 437.6302 -na---na--na--437.6302 438.9 N-026 N-025 440.4301 -na----na---na-440.4301 441.52 N-028 N-026 444.3401 -na--na---na-444.3401 444.82 N-029 N-028 445.7641 --na--na----na-445.764 446.2 N-031 N-029 445.934 -na--na--na-445.934 446.47 N-032 N-031 447.8239 -na--na---na-447.8239 449.01 N-033 N-032 448.994 -na--na---na-448.994 450.1 N-035 N-033 449.4039 -na--na--na-449.4039 451.24 N-036 N-035 451.6238 -na--na--na-451.6238 452.98 N-037 N-036 452.5651 -na--na--na-452.5651 453.8 N-039 N-037 453.065 --na--na--na--453.065 454.27 N-040 N-039 455.835 --na---na--na--455.835 457.02 N-041 N-040 458.6864 --na--na--na-458.6864 459.3 N-043 N-041 458.8464 --na--na--na-458.8463 459.71 N-044 N-043 466.1862 -na--na----na--466.1862 467.86 • Table 'B.8. Hydrograph Routing -West Basin -10-Year Storm ROUTEHYD O THRU [Existing West] USING TYPE1A AND (10 yr] NOTZERO ACTUAL Reach Area Flow FullQ % Full nDepth Size nVel Nel CBasin I Hyd ac cfs cfs ratio ft ft/s ft/s ------- D-021 2.9 1.1262 215.99 0.01 0.4269 X-Sect 3.6099 --w-001 D-020 2.9 1.126 75.0242 0.02 0.417 X-Sect 3.2085 ---- P-016 19.2 5.7252 10.5228 0.54 0.5258 12" Diam 13.6802 13.398 w-002 D-019 19.2 5.7243 212.76 0.03 0.8706 X-Sect 4.9958-- D-018 21.1 6.2369 251.93 0.02 0.3597 X-Sect 7.2932--ex_west P-015 21.1 6.2355 7.7298 0.81 0.6807 12" Diam 10.9508 9.8418 D-017 21.1 6.2346 138.18 0.05 0.5336 X-Sect 4.3923- D-016 21.1 6.2343 452.04 0.01 0.3664 X-Sect 6.4244- P-014 22.3 6.6546 7.9881 0.83 o. 6973 12" Diam 11.3797 10.1708 w-003 D-015 22.3 6.6534 160.64 0.04 0.6285 X-Sect 4.6707- D-014 22.3 6.653 200 0.03 0.827 X-Sect 5.1746- P-013 22.3 6.652 10.6228 0.63 0.5735 12" Diam 14.2771 13.5253 D-012 22.3 6.6504 290.67 0.02 0.8162 X-Sect 5.757- D-011 22.3 6.6488 320.43 0.02 0.516 X-Sect 5.0632- D-010 25.5 7.6794 1040.88 0.01 0. 7546 X-Sect 7.3444-w-004 P-012 25.5 7.6772 7.0631 1.09 -1 12"Diam 1.0869 8.9931 P-011 25.5 7.6747 6.9402 1.11 -1 12" Diam 1.1058 8.8365 P-010 25.5 7.6721 8.217 0.93 0.7657 12" Diam 11.8884 10.4623 P-009 25.5 7.6702 7.6431 1 0.8229 12" Diam 11.0927 9.7315 P-008A 27.7 8.4447 4.8684 1.73 -1 12" Diam 1.7346 6.1986 w-005 P-008 31.5 9.6483 6.8722 1.4 -1 12" Diam 1.404 8.75 w-006 P-007 31.5 9.6459 6.4104 1.5 -1 12" Diam 1.5047 8.162 P-006 31.5 9.6425 7.4569 1.29 -1 12" Diam 1.2931 9.4945 P-005 39.3 12.2397 9.9629 1.23 -1 12" Diam 1.2285 12.6852 w-007 P-004 39.3 12.2337 7.7824 1.57 -1 12" Diam 1.572 9.9088 D-009 39.3 12.2305 93.993 0.13 0.867 X-Sect 3.43- D-008 39.3 12.2302 112.96 0.11 0.5807 X-Sect 7.6019- P-003 39.3 12.2269 6.2952 1.94 -1 12" Diam 1.9423 8.0153 D-007 39.3 12.2225 107.57 0.11 0.7439 X-Sect 4.7079- D-006 39.3 12.2223 964.56 0.01 0.5074 X-Sect 9.6143- P-002 39.3 12.2172 6.1462 1.99 -1 12" Diam 1.9878 7.8256 D-005 39.3 12.2169 -0 0.915 X-Sect 4.2335- D-004 39.3 12.207 44.3354 0.28 0. 7349 X-Sect 5.8637- D-003 39.3 12.1945 313.41 0.04 0.7226 X-Sect 5.3815 - D-002 39.3 12.1624 770.99 0.02 0. 7234 X-Sect 1.7335- D-001 39.3 12.1621 146.32 0.08 0.5527 X-Sect 8.9201 - P-001 48.3 13.7386 8.2043 1.67 -1 12" Diam 1.6746 10.4461 w-008 Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node fl fl fl fl ft fl N-001 373.66 N-002 N-001 397.4953 -na--na---na--380.5 380.4 N-003 N-002 381.0999 -na--na--na-380.43 380.33 N-004 N-003 382.8899 -na--na--na-382.3 382.2 N-005 N-004 390.363 -na--na--na-390.35 390.25 ., N-006' N-005 398.8499 --na---na--na--398.78 398.68 N-007 N-006 398.1499 -na---na----na-398.1499 398.68 N-008 N-007 406.7091 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na---na--399.4 399.3 N-011 N-010 400.4899 --na----na----na-400.32 400.22 N-012 N-011 402.893 --na---na---na-401.7 401.6 N-014 N-012 401.9299 --na----na----na-401.9 401.8 N-015 N-014 402.4099 --na----na----na--402.4099 402.6 N-016 N-015 414.9783 3.7712 0.0341 -----406.11 406.01 N-017 N-016 412.823 2.3405 0.0303 ----406.41 406.31 N-018 N-017 412.9798 2.3422 0.0092 ---408.24 408.14 N-019 N-018 421.5153 ----413.82 413.72 N-019A N-019 428.7839 1.7952 0.0134 ---420.78 420.68 N-020 N-019A 424.1394 ---422.6 422.5 N-021 N-020 431.693 1.4817 0.0162 ----429.95 429.85 N-022 N-021 431.8735 1.4827 0.0057 ---430.3965 434 N-023 N-022 438.0848 1.4837 0.0053 ---436.69 436.59 N-024 N-023 440.4391 --na----na---na-438.3 438.2 N-025 N-024 438.69 --na----na----na-438.69 438.9 N-026 N-025 441.4899 -na--na--na-441.4899 441.52 N-028 N-026 445.3998 --na----na---na--444.92 444.82 N-029 N-028 447.9408 --na---na---na-446.3 446.2 N-031 N-029 446.47 --na---na----na-446.47 446.47 N-032 N-031 448.3599 --na--na---na-448.3599 449.01 N-033 N-032 451.1722 -na---na--na-450.2 450.1 N-035 N-033 450.6099 -na---na--na-450.6099 451.24 N-036 N-035 452.8299 -na---na--na-452.8299 452.98 N-037 N-036 454.9681 -na--na--na-453.9 453.8 N-039 N-037 454.3999 --na---na---na-454.37 454.27 N-040 N-039 457.14 --na---na---na-457.12 457.02 N-041 N-040 460.2915 -na--na---na-459.4 459.3 N-043 N-041 459.5599 --na---na---na-459.5599 459.71 N-044 N-043 466.8998 -na----na----na--466.8998 467.86 Table·B.9. Hydrograph Routing -West Basin -25-Year Storm ROUTEHYD [] THRU [Existing West] USING TYPE1A AND [25 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio fl ft/s ft/s --------- 0-021 2.9 1.4193 215.99 0.01 0.4655 X-Sect 3.8249 -w-001 0-020 2.9 1.419 75.0242 0.02 0.4548 X-Sect 3.3995 ·-- P-016 19.2 7.2941 10.5228 0.69 0.6125 12" Diam 14.4658 13.398 w-002 0-019 19.2 7.2903 212.76 0.03 0.9533 X-Sect 5.3071 --·· 0-018 21.1 7.9622 251.93 0.03 0.4124 X-Sect 7.8517 --ex_west P-015 21.1 7.9606 7.7298 1.03 0.8494 12" Diam 11.1952 9.8418 0-017 21.1 7.9596 138.18 0.06 0.6103 X-Sect 4.7161 - 0-016 21.1 7.9593 452.04 0.02 0.4154 X-Sect 6.9302- P-014 22.3 8.4903 7.9881 1.06 0.8943 12" Diam 11.4571 10.1708 w-003 D-015 22.3 8.4889 160.64 0.05 0. 7052 X-Sect 5.0142 - D-014 22.3 8.4884 200 0.04 0.9062 X-Sect 5.4996 --- P-013 22.3 8.4872 10.6228 0.8 0.676 12" Diam 15.0227 13.5253 0-012 22.3 8.4854 290.67 0.03 0.8943 X-Sect 6.1186 - D-011 22.3 8.4835 320.43 0.03 0.5836 X-Sect 5.4511 -- D-010 25.5 9.7892 1040.88 0.01 0.8265 X-Sect 7.8039 -w-004 P-012 25.5 9.7867 7.0631 1.39 -1 12" Diam 1.3856 8.9931 P-011 25.5 9.7842 6.9402 1.41 -1 12" Diam 1.4098 8.8365 P-010 25.5 9.7811 8.217 1.19 -1 12" Diam 1.1903 10.4623 P-009 25.5 9.7791 7.6431 1.28 -1 12" Diam 1.2795 9.7315 P-008A 27.7 10.7564 4.8684 2.21 -1 12" Diam 2.2095 6 .1986 w-005 P-008 31.5 12.2532 6.8722 1.78 -1 12" Diam 1.783 8.75 w-006 P-007 31.5 12.2295 6.4104 1.91 -1 12" Diam 1.9077 8.162 P-006 31.5 12.214 7.4569 1.64 -1 12" Diam 1.6379 9.4945 P-005 39.3 15.4537 9.9629 1.55 -112"Diam 1.5511 12.6852 w-007 P-004 39.3 15.439 7.7824 1.98 -1 12" Diam 1.9838 9.9088 D-009 39.3 15.4332 93.993 0.16 0. 9703 X-Sect 3.6728- D-008 39.3 15.4329 112.96 0.14 0.6524 X-Sect 8.1307 - P-003 39.3 15.4277 6.2952 2.45 -1 12· Diam 2.4507 8.0153 D-007 39.3 15.4211 107.57 0.14 0.8378 X-Sect 5.0372 -- D-006 39.3 15.4209 964.56 0.02 0.5537 X-Sect 10.1896 - P-002 39.3 15.4136 6.1462 2.51 -1 12" Diam 2.5078 7.8256 D-005 39.3 15.4133 -0 0.915 X-Sect 5.3412 - 0-004 39.3 15.3973 44.3354 0.35 0.8232 X-Sect 6.2522- 0-003 39.3 15.3784 313.41 0.05 0.8043 X-Sect 5.7771 - 0-002 39.3 15.3305 770.99 0.02 0. 7 49 X-Sect 1.8482- D-001 39.3 15.3302 146.32 0.1 0.61 X-Sect 9.5841 -- P-001 48.3 17.4789 8.2043 2.13 -1 12" Diam 2.1304 10.4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node fl fl fl fl fl fl N-001 373.66 N-002 N-001 412.2399 -na--na--na-380.5 380.4 N-003 N-002 381.1 -na--na---na-380.43 380.33 N-004 N-003 382.8899 -na--na--na-382.3 382.2 N-005 N-004 390.6017 -na--na---na--390.35 390.25 N-006 • N-005 398.85 --na----na---na--398.78 398.68 N-007 N-006 398.1499 --na----na----na-398.1499 398.68 N-008 N-007 411. 7735 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.4899 -na----na---na-400.32 400.22 N-012 N-011 404.2625 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na---na--401.9 401.8 N-015 N-014 402.4099 --na----na----na--402.4099 402.6 N-016 N-015 422.4271 6.0118 0.0544 ---406.11 406.01 N-017 N-016 416.8114 3.7554 0. 0486 -----406.41 406.31 N-018 N-017 416.9514 3.7649 0.0148 -----408.24 408.14 N-019 N-018 429.5789 -----413.82 413.72 N-019A N-019 437.9548 2.9125 0.0218 --420.78 420.68 N-020 N-019A 426.2303 ---422.6 422.5 N-021 N-020 436.8487 2.4083 0.0264-429.95 429.85 N-022 N-021 438.8036 2.4098 0.0093 --434.1 434 N-023 N-022 442.3643 2.4111 0.0087 ---436.69 436.59 N-024 N-023 442. 7826 --na---na--na-438.3 438.2 N-025 N-024 438.69 --na----na----na-438.69 438.9 N-026 N-025 441.4899 -na----na--na-441.4899 441.52 N-028 N-026 445.3998 --na---na----na-444.92 444.82 N-029 N-028 449. 7335 -na----na---na-446.3 446.2 N-031 N-029 446.47 -na--na---na-446.47 446.47 N-032 N-031 448.3599 -na----na---na-448.3599 449.01 N-033 N-032 452.966 -na----na--na-450.2 450.1 N-035 N-033 450.6099 -na---na--na-450.6099 451.24 N-036 N-035 452.8299 -na---na---na-452.8299 452.98 N-037 N-036 456.3148 --na---na---na-453.9 453.8 N-039 N-037 454.3999 -na----na--na-454.37 454.27 N-040 N-039 457.1399 --na----na--na-457.12 457.02 N-041 N-040 461.6094 -na--na--na-459.4 459.3 N-043 N-041 459.5599 --na---na---na-459.5599 459.71 N-044 N-043 466.8998 --na---na----na-466.8998 467.86 Table 8.10. Hydrograph Routing -West Basin -SO-Year Stomi ROUTEHYD D THRU [Existing West] USING TYPE1A AND (50 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s -------· D-021 2.9 1.5685 215.99 0.01 0.4833 X-Sect 3.9215 ---w-001 D-020 2.9 1.5683 75.0242 0.02 0.4722 X-Sect 3.4853 - P-016 19.2 8.0999 10.5228 0.77 0.6581 12" Diam 14.7787 13.398 w-002 D-019 19.2 8.0896 212.76 0.04 0.9912 X-Sect 5.4469- D-018 21.1 8.8435 251.93 0.04 0.4372 X-Sect 8.1008 --ex_west P-015 21-1 8.8417 7.7298 1.14 -112"Diam 1.1439 9.8418 D-017 21.1 8.8407 138.18 0.06 0.6463-X-Sect 4.8603 -- D-016 21.1 8.8404 452.04 0.02 0.4384 X-Sect 7.156- P-014 22.3 9.434 7.9881 1.18 -1 12" Diam 1.181 10.1708 w-003 D-015 22.3 9.4262 160.64 0.06 0.7412 X-Sect 5.1673-- D-014 22.3 9.4257 200 0.05 0.9425 X-Sect 5.6454 -- P-013 22.3 9.4245 10.6228 0.89 0.7329 12" Diam 15.2781 13.5253 D-012 22.3 9.4224 290.67 0.03 0.9301 X-Sect 6.2809- D-011 22.3 9.4204 320.43 0.03 0.6154 X-Sect 5.6241 -- D-010 25.5 10.8663 1040.88 0.01 0.8595 X-Sect 8.0101 -w-004 P-012 25.5 10.8659 7.0631 1.54 -1 12" Diam 1.5384 8.9931 P-011 25.5 10.8622 6.9402 1.57 -1 12" Diam 1.5651 8.8365 P-010 25.5 10.8581 8.217 1.32 -1 12" Diam 1.3214 10.4623 P-009 25.5 10.8544 7.6431 1.42 -1 12' Diam 1.4201 9.7315 P-008A 27.7 11.9326 4.8684 2.45 -1 12" Diam 2.4511 6.1986 w-005 P-008 31.5 13.5621 6.8722 1.97 -1 12" Diam 1.9735 8.75 w-006 P-007 31.5 13.5297 6.4104 2.11 -1 12" Diam 2.1106 8.162 P-006 31.5 13.5123 7.4569 1.81 -1 12' Diam 1.8121 9.4945 P-005 39.3 17.0801 9.9629 1.71 -1 12" Diam 1.7144 12.6852 w-007 P-004 39.3 17.0634 7.7824 2.19 -1 12' Diam 2.1926 9.9088 D-009 39.3 17.0568 93.993 0.18 1.0185 X-Sect 3.7809 - D-008 39.3 17.0564 112.96 0.15 0.6858 X-Sect 8.366- P-003 39.3 17.0509 6.2952 2.71 -1 12' Diam 2.7086 8.0153 D-007 39.3 17.0435 107.57 0.16 0.8816 X-Sect 5.1838 --- D-006 39.3 17.0432 964.56 0.02 0.5748 X-Sect 10.4477- P-002 39.3 17.0355 6.1462 2.77 -1 12" Diam 2.7717 7.8256 D-005 39.3 17.0353-0 0.915 X-Sect 5.9032- D-004 39.3 17.0172 44.3354 0.38 0.8642 X-Sect 6.4254 -- D-003 39.3 16.9961 313.41 0.05 0.8428 X-Sect 5.9539- D-002 39.3 16.9427 770.99 0.02 0. 7591 X-Sect 1.9232 -- D-001 39.3 16.9424 146.32 0.12 0.6369 X-Sect 9.8817 - P-001 48.3 19.3916 8.2043 2.36 -1 12" Diam 2.3636 10.4461 w-008 Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ff ft ft ft ft ff N-001 373.66 N-002 N-001 421.1453 -na--na---na-380.5 380.4 N-003 N-002 381.1 -na--na--na-380.43 380.33 N-004 N-003 382.8899 -na--na----na-382.3 382.2 N-005 N-004 390.6621 -na---na--na--390.35 390.25 . -1 • N-006. N-005 398.8499 --na----na----na-398.78 398.68 N-007 N-006 398.1499 --na----na----na--398.1499 398.68 N-008 N-007 414.7916 --na---na----na-399.4 399.3 N-010 N-008 400.3799 -na----na----na--399.4 399.3 N-011 N-010 400 .5191 --na----na----na--400.32 400.22 N-012 N-011 405.0781 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na---na-401.9 401.8 N-015 N-014 402.4099 --na----na---na--402.4099 402.6 N-016 N-015 426.8611 7.3437 0.0665 -----406.11 406.01 N-017 N-016 419.1824 4.5962 0.0595 -----406.41 406.31 N-018 N-017 419.3115 4.6079 0.0181 ------408.24 408.14 N-019 N-018 434.3575 ------413.82 · 413.72 N-019A N-019 443.3864 3.5843 0.0268 ----420.78 420.68 N-020 N-019A 427.4875 -----422.6 422.5 N-021 N-020 440.1545 2.9679 0.0325 ---429.95 429.85 N-022 N-021 440.8607 2.9701 0.0115 ------434.1 434 N-023 N-022 444.2857 2.9721 0.0107 -----436.69 436.59 N-024 N-023 444.2004 --na----na---na--438.3 438.2 N-025 N-024 438.6899 --na---na---na-438.6899 438.9 N-026 N-025 441.4899 --na--na---na--441.4899 441.52 N-028 N-026 445.3998 --na---na---na--444.92 444.82 N-029 N-028 450.8166 --na---na---na--446.3 446.2 N-031 N-029 446.47 -na--na---na-446.47 446.47 N-032 N-031 448.3599 -na----na--na--448.3599 449.01 N-033 N-032 453.324 --na---na--na-450.2 450.1 N-035 N-033 450.6099 -na--na--na-450.6099 451.24 N-036 N-035 452.8299 --na--na--na-452.8299 452.98 N-037 N-036 457.129 --na--na--na-453.9 453.8 N-039 N-037 454.3999 --na---na----na-454.37 454.27 N-040 N-039 457.1399 -na----na----na-457.12 457.02 N-041 N-040 462.4097 --na--na---na-459.4 459.3 N-043 N-041 459.5599 -na---na----na-459.5599 459.71 N-044 N-043 466.8998 --na---na---na-466.8998 467.86 Table13.11. Hydrograph Routing -West Basin -100-Year Stonn ROUTEHYD [] THRU [Existing West] USING TYPE1A AND [100 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs els ratio ft fl/s fl/s ----------- D-021 2.9 1.7191 215.99 0.01 0.5002 X-Sect 4.0124 --w-001 D-020 2.9 1.7188 75.0242 0.02 0.4887 X-Sect 3.5662 --·· P-016 19.2 8.9147 10.5228 0.85 0.7064 12" Diam 15.0315 13.398 w-002 D-019 19.2 8.8982 212.76 0.04 1.0272 X-Sect 5.5783 ··-- D-018 21.1 9.7341 251.93 0.04 0.4611 X-Sect 8.3334 ---ex_west P-015 21.1 9.7323 7.7298 1.26 -1 12" Diam 1.2591 9.8418 D-017 21.1 9.7313 138.18 0.07 0.6809 X-Sect 4.9949 '-- D-016 21.1 9.7309 452.04 0.02 0.4605 X-Sect 7.3672 -- P-014 22.3 10.3918 7.9881 1.3 -1 12" Diam 1.3009 1 O .1708 w-003 D-015 22.3 10.3745 160.64 0.06 0.7757 X-Sect 5.3102 ·- D-014 22.3 10.3736 200 0.05 0.977 X-Sect 5.7823 --- P-013 22.3 10.3718 10.6228 0.98 0.7991 12" Diam 15.4151 13.5253 D-012 22.3 10.3694 290.67 0.04 0.9642 X-Sect 6.4331 ---- D-011 22.3 10.3672 320.43 0.03 0.6459 X-Sect 5.7856 - D-010 25.5 11.9547 1040.88 0.01 0.8908 X-Sect 8.2036 --w-004 P-012 25.5 11.9546 7.0631 1.69 -1 12" Diam 1.6925 8.9931 P-011 25.5 11.9518 6.9402 1.72 -1 12" Diam 1.7221 8.8365 P-010 25.5 11.9391 8.217 1.45 -1 12" Diam 1.453 10.4623 P-009 25.5 11.8994 7.6431 1.56 -1 12" Diam 1.5569 9.7315 P-008A 27.7 13.0768 4.8684 2.69 -1 12" Diam 2.6861 6 .1986 w-005 P-008 31.5 14.8216 6.8722 2.16 -1 12" Diam 2.1567 8.75 w-006 P-007 31.5 14.7641 6.4104 2.3 -1 12" Diam 2.3031 8.162 P-006 31.5 14.7397 7.4569 1.98 -1 12" Diam 1.9766 9.4945 P-005 39.3 18.6376 9.9629 1.87 -1 12" Diam 1.8707 12.6852 w-007 P-004 39.3 18.6131 7.7824 2.39 -1 12" Diam 2.3917 9.9088 D-009 39.3 18.6037 93.993 0.2 1.0612 X-Sect 3.8828 - D-008 39.3 18.6034 112.96 0.16 0.7161 X-Sect 8.5744- P-003 39.3 18.5959 6.2952 2.95 -1 12" Diam 2.954 8.0153 D-007 39.3 18.5866 107.57 0.17 0.9214 X-Sect 5.3133 --- D-006 39.3 18.5863 964.56 0.02 0.5938 X-Sect 10.6766 ---- P-002 39.3 18.5762 6.1462 3.02 -1 12" Diam 3.0224 7.8256 D-005 39.3 18.576 -0 0. 915 X-Sect 6.4371 -- D-004 39.3 18.5514 44.3354 0.42 0. 9012 X-Sect 6.5778 -- D-003 39.3 18.5234 313.41 0.06 0.8774 X-Sect 6.1089- D-002 39.3 18.4536 770.99 0.02 0. 7682 X-Sect 1.9897 - D-001 39.3 18.4532 146.32 0.13 0.6611 X-Sect 10.141 ---- P-001 48.3 21.1994 8.2043 2.58 -1 12" Diam 2.5839 10.4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.66 N-002 N-001 430.4121 --na---na--na-380.5 380.4 N-003 N-002 381.0999 -na--na---na-380.43 380.33 N-004 N-003 382.8899 -na---na--na-382.3 382.2 N-005 N-004 390.6975 --na--na---na-390.35 390.25 -l N-00& N-005 398.8499 -na----na---na--398.78 398.68 N-007 N-006 398.1499 -na----na----na--398.1499 398.68 N-008 N-007 417.9379 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na-399.4 399.3 N-011 N-010 400.5711 --na----na---na--400.32 400.22 N-012 N-011 405.9302 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 --na---na----na-402.4099 402.6 N-016 N-015 431.5039 8.7441 0.0791 -----406.11 406.01 N-017 N-016 421.6752 5.469 0.0707 -----406.41 406.31 N-018 N-017 421.7617 5.4872 0.0216 -----408.24 408.14 N-019 N-018 439.3409 ---413.82 413.72 N-019A N-019 449.133 4.3046 0.0322 ---420.78 420.68 N-020 N-019A 428.8355 --422.6 422.5 N-021 N-020 443.6975 3.5882 0.0393 --429.95 429.85 N-022 N-021 443.1411 3.5959 0.0139 -----434.1 434 N-023 N-022 446.4317 3.5976 0.0129 -----436.69 436.59 N-024 N-023 445.7808 --na---na---na--438.3 438.2 N-025 N-024 438.6899 -na----na----na-438.6899 438.9 N-026 N-025 441.4899 -na--na---na--441.4899 441.52 N-028 N-026 445.3998 -na----na---na-444.92 444.82 N-029 N-028 452.0266 -na---na--na--446.3 446.2 N-031 N-029 446.47 -na---na---na-446.47 446.47 N-032 N-031 448.3599 -na--na--na-448.3599 449.01 N-033 N-032 454.3832 -na--na---na-450.2 450.1 N-035 N-033 450.6099 -na--na---na-450.6099 451.24 N-036 N-035 452.8299 -na--na---na-452.8299 452.98 N-037 N-036 458.0387 -na--na----na-453.9 453.8 N-039 N-037 454.3999 -na--na----na-454.37 454.27 N-040 N-039 457.1399 -na--na---na-457.12 457.02 N-041 N-040 463.3042 -na---na--na-459.4 459.3 N-043 N-041 459.5599 -na---na0 ---na-459.5599 459.71 N-044 N-043 466.8998 -na---na----na--466.8998 467.86 Table·B.12. Hydrograph Routing -West Basin -Summary Table 2-Year 10-Year 25-Year 50-Year 100-Year Freeboard Freeboard Freeboard Freeboard Freeboard Reach ID From Node To Node ft ft ft ft ft N-001 P-001 N-002 N-001 Overlap Overlap Overlap Overlap Overlap D-001 N-003 N-002 Overlap Overlap Overlap Overlap Overlap D-002 N-004 N-003 Overlap Overlap Overlap Overlap Overlap D-003 N-005 N-004 0.37 overlap Overlap Overlap Overlap D-004 N-006 N-005 0.30 Overlap Overlap Overlap Overlap D-005 N-007 N-006 0.91 0.53 0.53 0.53 0.53 P-002 N-008 N-007 Overlap Overlap Overlap Overlap Overlap D-006 N-010 N-008 Overlap Overlap Overlap Overlap Overlap D-007 N-011 N-010 Overlap Overlap Overlap Overlap Overlop P-003 N-012 N-011 Overlap Overlap Overlap Overlap Overlap D-008 N-014 N-012 Overlap Overlap Overlap Overlap Overlop D-009 N-015 N-014 0.19 0.19 0.19 0.19 0.19 P-004 N-016 N-015 0.11 Overlap Overlap Overlap Overtop P-005 N-017 N-016 Overlap Overtap Overlap Overlap Overtop P-006 N-018 N-017 0.49 Overlap Overlap Overlap Overlop P-007 N-019 N-018 2.57 Overlap Overlap Overtap Overlap P-008 N-019A N-019 1.39 Overlap Overlop Overtop Overtop P-OOBA N-020 N-019A 2.40 Overlap Overlap Overtap Overtop P-009 N-021 N-020 1.40 Overtap Overlap Overtap Overtop P-010 N-022 N-021 3.38 3.60 Overtap Overtap Overlap P-011 N-023 N-022 1.04 Overlap Overtop Overtap Overlap P-012 N-024 N-023 0.96 Overlap Overlap Overtap Overlop D-010 N-025 N-024 1.27 0.21 0.21 0.21 0.21 D-011 N-026 N-025 1.09 0.03 0.03 0.03 0.03 D-012 N-028 N-026 0.48 Overlap Overtap Overtap Overlap P-013 N-029 N-028 0.44 Overlap Overlap Overlap Overlap D-014 N-031 N-029 0.54 0.00 0.00 0.00 0.00 D-015 N-032 N-031 1.19 0.65 0.65 0.65 0.65 P-014 N-033 N-032 1.11 Overlap Overtop Overtap Overlap D-016 N-035 N-033 1.84 0.63 0.63 0.63 0.63 D-017 N-036 N-035 1.36 0.15 0.15 0.15 0.15 P-015 N-037 N-036 1.23 Overtap Overlap Overlap Overtop D-018 N-039 N-037 1.20 Overlap Overlap Overlap Overlop D-019 N-040 N-039 1.19 Overlap Overlap Overtap Overtap P-016 N-041 N-040 0.61 Overtap Overlap Overtap Overlap D-020 N-043 N-041 0.86 0.15 0.15 0.15 0.15 D-021 N-044 N-043 1.67 0.96 0.96 0.96 0.96 ' -, z SUJSOS a6oUJOJO .LV'Id TI3CTN3A3 'ON 103/'0lld i i \.38'~,l~v rna1~1 .:JO Y.6 SI 311S ', 1 ·, j. :-.. ., ' ' ~/ ! j ........ zo,m/s .... ......... LOLa-~ 6S.OS& ¥A 'NCJJGI 'lS Hl9U :3S 9J8trl ~Hl>ID<l!ltra 1!AC !trJ.1aauJ!t13 snozovu (:JI/ £'6)/ ,:i-s'O,xa, "113ITN3/\3] J .".".::.s:, ,._,- .. H !JJJ NI 31WJS 00~ '" )i 200 400 SCALE IN FEET ' Haozous Engineering CIVIL ~Gll££RING 14816 SE. U6TH ST, RENTON, \/A 980!59 "'2'5-23S-2707 ,,,_ ... QAID EVENDELL PLAT ""'""" .. m Land Use/Cover Types I &JM I .;,210• I &lM 8/12/0Z • PROJECT NO. FlGi.11 3 _i ... • ... ... SColl.£ DI FttT LEGEND a Co. tch Bo.sin P5 Pipe ID j10-Yeo.r j Flooding Return Period ~ 11 ~--'"r:, -I I --1 I 9 I I l;j· ,, . ,, "_I i I ;J ' ,' ,.] l --~'-' ',(, ------• ,, -·".'.( P161~ -'- P151(~ ~ "' pf~~ :!~,~-Ye~;Ff~~~' P11~·. --.,,_,.-_ ·-· · · -,---·-·--·-----~-_-,• Pl ~:: H~5-Yeb.~ [, 1 l "': '"·: •. :T ,;.,, 1,,r} ;~; u-,~' ,-· _,:. -'-~---··-;--Lr··---r ~--::'"" ~~Qi :11ok -~:{ 0 t·.: E j 0 ~ 11 0:, 'I •,o;•;,..; ''..':~ . . --·-·-··-r ·----~, Pl J :-:;; i' _, ,~, t··- ,1 ,, ::t ii', a, .... i (~;- ~' .. •••• -!"', _'yi;[{:;~J; if) , ·,_,_; H) ·--·-~·-'-" ;.: ,c; .. r o,f:-·· · . .) ,,ltl1ru, ' -..,,_, ···-·····----\·, .. P117, ~ .' , ·---·-• ----····-l:,,;._:::,_• P116 I '; j2:cYeo.n j ,) I ~\J1:~~;,;:';f '•; , ;,,"'.<f TH 1 J_ -)11 (l Ci; t)_ ; M ,,;,. '--~.: ~)01 (~{,(~: .. :·,! ., r ii~; ;:'. ~-;-' -. J~~;j['i'.i1,;f r r: _. ,, f.'.._ r "Jt.( i ! ,, 'I_. I :-,1 -, ~ ) Haozoua Engineering CIYL ENGiNlil,G EVENDELL PLAT 14816 IE 1161H· IT, MNTIIN; W. _, tlS -LIUJ DES!CHEO BY: o.-.m UI 1/llt/lll D!!A'MI ll~ -DATE: 11/12/111 Flooding Locations • PROJECT NO. FIGURE 4 SE 144TH STREET LEVEL 3 DOWNSTREAM DRAINAGE ANALYSIS Prepared for: Mr. Dave Petrie 811 So. 273rd Ct. Des Moines, WA 98198 KBS Development 12320 NE 8th Street Suite 100 Bellevue WA 98005 Eagle Creek Land & Development, LLC 13701 SE 253rd St Kent, WA 98042 r -·----------·---------------·- F-'XPi RE.\: :;/ l')/09 ······-----·----··----···----------··-- \ REVISION I oo§@§QW§ill) JUL O 2 2007 K.C. D.D.E.S. Prepared by: Ed McCarthy. P.E., P.S. 9957 171st Avenue SE Renton, WA 98059 Tel (4251 271-5734 Fax (425) 2713432 MAIN FILE COPY June 15, 2007 Acknowledgements SE 144th Street LEVEL 3 DOWNSTREAM DRAINAGE ANALYSIS Prepared by: Ed McCarthy, P.E., P.S. 9957 171 '' Avenue SE Renton, WA 98059 Tel. (425) 271-5734 Fax (425) 271-3432 Prepared for: Mr. Dave Petrie 811 So. 273rd Ct. Des Moines, WA 98198 KBS Development 12320 NE 8th Street Suite 100 Bellevue WA 98005 Eagle Creek Land & Development, LLC 13701 SE 253rd St Kent, WA 98042 June 16, 2007 TABLE OF CONTENTS I. Background Information ............................................................................................. 1-1 2. Hydrologic and Hydraulic Analysis of SE 144th Street.. ............................................ 2-1 3. Drainage Mitigation Options ...................................................................................... 3-1 4. Key Results and Recommendations ............................................................................ 4-1 5. References ................................................................................................................... 5-1 LIST OF TABLES Table 1. Contributing Basins .......................................................................................... 2-4 Table 2. Peak Flow Rates at Key Locations ................................................................... 2-8 LIST OF FIGURES Figure I. Vicinity Map .................................................................................................... 1-2 Figure 2. Study Area ....................................................................................................... 2-2 Figure 3. Soils Map ......................................................................................................... 2-3 Figure 4. Basin Map ........................................................................................................ 2-6 Figure 5. SE 144 1h Street Conveyance System ............................................................... 2-9 Figure 6. Offsite Mitigation Options .............................................................................. 3-2 APPENDICES Appendix A. Photographs of the Downstream System Appendix B. KCRTS Documentation for Contributing Basins Appendix B.1 KCRTS Time Series Calculations Appendix B.2 KCRTS Pond Designs Appendix B.3 KCRTS Peak Flow Rates Appendix C. XP-SWMM Model Results Appendix D. HEC-RAS Analysis of Roadway Conveyance ii 1. BACKGROUND INFORMATION This report provides an assessment of the conveyance system along SE 144th Street in the Renton Highlands area of King County, Washington (Figure!). The study area is located within a catchment of Orting Hill subbasin (Tributary 0307) of the Cedar River watershed (King County Department of Natural Resources, 1993 and 1997). The conveyance system has a contributing drainage area of 253 acres. The conveyance route is downstream from three proposed single- family residential developments that are currently under drainage review at King County DDES. These developments include Threadgill Plat, Liberty Gardens, and Cavella. This Level 3 Downstream Drainage Analysis has been prepared at the request ofDDES. Flooding currently occurs at locations along the SE J44'h Street conveyance system. Flooding has been observed at the intersection of the 162nd Avenue right-of-way and SE 144th Street (Photo No. I in Appendix A). In addition, King County Roads Division has recently constructed conveyance improvements at the intersection of 160th A venue SE and SE 144'h Street, presumably to collect overflow from surrounding catch basins. While the conveyance system is apparently undersized for its contributing basin, there is a surprisingly little documentation in King County's records that flooding exists or has occurred in the past along SE I 44th Street. Neither the long-time owner of Alpine Nursery nor an original resident at Carolwood, that I interviewed, had observed road flooding along SE I 44•h Street over the past several years. The evaluations presented in this report are intended accomplish the following: .. • • • Delineate the conveyance network's contributing basins and quantify the flow rates draining to the conveyance network. Estimate the conveyance capacity of the system, including the 18-inch diameter pipe, northerly roadside ditch, and roadway. Identify areas of flooding . Develop conceptual drainage solutions to mitigate impacts from the proposed and future development projects. ].] SE 144°' Slreet-June 2()()7 ~)D_,_ ',{PO ,. ·1 ,._ I &',:l>i.'_--~ ·~ ' - ' \ -' i.~ ··I:,, 1.··. .-;- :! :! I :1 ! ,_ - I;' ' Vicinity Map SE 144th Street Drainage Analysis King County, Washington J_ 0 ,~---/-' -_,--' : I ' ; ' I 2,000 Feet ,, •. i-i ' ., \ \ '' -'\. ,i Ed McCarthy, PE, PS !185711181 Avenle SE -~--(425) 271.5134 F11< (425) 271-3432 -6115/07 Figure 1 2. HYDROLOGIC AND HYDRAULIC ANALYSIS OF SE 1.44™ STREET 2.1 Contributing Basins In effort to develop a hydrologic model of the basins contributing to the conveyance system along SE 144th Street, basin boundaries were delineated using the following resources: • • • • • • • • • • • • City of Renton aerial topography ( I-meter contours) Level I Downstream Drainage Analysis for Threadgill Plat (Baima & Holmberg, Inc . and Ed McCarthy, PE, PS. November 18, 2005) Level I Downstream Drainage Analysis for Evendell Plat (Haozous Engineering, June 15, 2001) Technical Information Report for Hamilton Place (Barghausen Consulting Engineers, June 2003) Technical Information Report for Evendell Plat (Haozous Engineering, June 15, 2001) Technical Information Report for Nichol's Plat (Haozous Engineering, May 2003) Technical Information Report for Liberty Grove (Daley-Morrow-Poblete, Inc., February 2003) Record drawings for stormwater design for Carolwood (May 1977) Record drawings for stormwater design for Liberty Lane (Doneshvar and Associates, PS, June 13, 1979) Record drawings for SE 144th Street (King County Department of Public Works, January 18, 1984) Record drawings for 154th Place SE Slope Stabilization Project (King County Department of Public Works, June 23, 1997) Field verification of key locations in the watershed The study area under consideration is shown in Figure 2. Cover types within the study area include those associated with relatively dense single-family residences, forest, and pasture. Soils in the watershed are mostly of the Alderwood series (Figure 3). However, a band of outwash soils (Everett series) exists along SE 144th Street, at the southern boundary of the study basin and extends to the south. In total, an area of253 acres was calculated to drain to the conveyance system (Table!). Based on cover type estimates, about 25 percent of the contributing area is effective impervious surfaces. The size and boundaries of the delineated sub basins draining to the conveyance system 2-1 SE I 44'1, Street -June 2007 Study Area SE 144th Street Drainage Analysis () 400 ....._ ___ --J Feet King Countl,_yJa~hington Ed McCarthy, PE, PS 9957 17 1st Avenue SE Renton, Wash ington 98 059 Phone: (42 5) 271 -5734 Fax: (425 127 1-3432 Date: 6/15 /07 Figure 2 -.. j ! 4th ,I ··1 1 i •• 11 1-_-' __ ,_, ·--·- •.J' '' i _ ~~L::T ~i, i__i_·::·;c '--:--' 4tti Ii . 'Ti· '' 1 I 136th ; i 'i ' : mAt1t ' ' ' :::;r, ! j 1 "\·I' I ' '. '1:lQlh : I T""j Soils Map SE 144th Street Drainage Analysis King County, Washington ' 1?41Ji ·, r •{/,~'IS> '' () 1,000 Feet " Ed McCarthy, PE, PS 9957171st Aierlle SE Rllnlo!\ ----l'l1<lM (425) 271-5734 Fax: (425) 271-3432 ,:, ,-.,,, ; co, . 1.:"i . ', :- 132n~ I .~ I~., !. .... :': 142Q;, ,. ' ~ 1' -5/03/07 Figure 3 Table 1. Contributing Basins Basin Till Till Till Outwash Outwash Outwash ID Forest Pasture Grass Forest Pasture Grass Impervious Total AC AC AC AC AC AC AC AC 10 -0.16 0.29 0.08 0.53 20 -0.30 1.05 0.51 1.86 30 -0.31 0.91 0.41 1.62 40 0.26 0.30 0.56 42 -0.03 0.96 0.67 1.66 44 0.99 0.99 50 0.51 0.51 52 -0.01 0.80 -0.01 0.80 1.15 2.77 54 0.03 0.03 0.83 0.04 0.04 1.24 1.44 3.64 60 0.52 0.52 70 -0.51 1.70 -0.34 1.13 1.34 5.04 80 5.28 0.12 4.35 0.59 0.01 0.48 3.40 14.23 90 0.40 0.40 100 0.45 0.33 0.61 0.17 1.56 106 2.50 0.12 3.34 0.12 3.34 4.64 14.05 110 6.43 12.24 12.33 7.10 38.10 120 0.58 1.00 1.58 130 2.49 7.12 5.80 1.58 16.99 200 4.45 0.14 1.79 1.18 7.56 210 3.31 1.70 4.60 2.93 12.55 220 1.56 1.90 3.46 230 3.95 5.71 9.66 232 1.38 ---1.38 240 3.65 4.48 8.13 241 0.23 2.99 3.68 6.90 244 0.71 11.46 10.75 4.68 27.60 250 -0.17 4.66 3.23 8.06 260 2.33 1.74 4.07 270 --2.22 1.60 3.82 300 9.47 1.73 4.13 1.56 16.89 304 2.12 1.36 5.73 3.74 12.95 306 1.25 0.15 0.28 0.08 1.75 310 9.32 ---9.32 320 8.92 0.18 0.33 0.09 9.52 330 1.37 0.34 0.62 0.17 2.50 59.71 42.22 75.40 0.63 1.32 10.47 62.98 252.73 Effective Impervious = 25% 2-4 SE 144'1' Street -June 2007 were driven by the locations of catch points and the watershed's topography. A total of 35 subbasins were delineated (Figure 4). Recent higher density single-family developments contributing to the conveyance system include Hamilton Place (Catchment C-260), Evendell Plat (Catchment C-230), Nichols Place (Catchment C-220), and Liberty Grove (Catchments C-240 and 241 ). The attenuation provided by the stonnwater ponds for these developments was included in the hydrologic model of the basin. In addition, the stonnwater pond for Carolwood (Catchment C-106) infiltrates runoff for at least up to the I 00-year event. Record drawings were also obtained for Serena Park (Catchments C-70 and C-80) and for Liberty Lane (Catchment C-330) but these older pipe detention systems from the late 1970's do not provide substantial detention volume and were not included in the hydrology model of the basin. Record drawings for the conveyance system along SE 1441h Street (King County Department of Public Works, January 18, 1984) were found to be accurate when checked against field observations and a recent field survey. The drawings show that the 18-inch diameter CMP is perforated in the upper half of the pipe. According to the plans, the pipe is set in a gravel bed to allow infiltration. This design encourages infiltration and groundwater recharge by taking advantage of the relatively flat pipe slope and surrounding outwash soils. While this pipe configuration provides baseflow benefits to down gradient tributaries of the Cedar River, the perforations do not provide much flood relief during large flows. Assuming a reasonable infiltration rate of 10 inches per hour, and a 42-inch wide infiltration surface that extends from l 62ru1 A venue SE to 1561 h Avenue SE, the rate of water infiltrating from the pipe to the native soil would be roughly 1.5 cubic foot per second. This rate is small relative to the predicted I 00- year flow rate of almost 40 cubic feet per second. While the infiltration component of the conveyance system has been noted, it was not included in the hydraulic model of the system. 2.2 Hydrology Assessment of Contributing Basins The hydrologic model KCRTS was used to develop runoff time series for each of the basins contributing to the SE 1441h Street Conveyance system (Appendix B.l). The reduced 1-hour KCRTS time series data set was used for the Seatac rainfall region with a correction factor of 1.0. The 1-hour time series is appropriate for the modeling conducted because flows from a sizeable portion of the basin are routed through detention ponds. In addition, the KCRTS modeling methodology neglects attenuation that occurs when time series are routed through the watershed. Time series routing through stormwater ponds was conducted to characterize the attenuation provided by some of the more significant storage areas in the basin, including the stormwater detention system for Hamilton Place (Catchment C-260), Evendell Plat (Catchment C-230), Nichols Place (Catchment C-220), and Liberty Grove (Catchments C-240 and 241). In addition, the infiltration stormwater pond for Carolwood was assumed to infiltrate all runoff from 2-5 SE 14¢" Street-June 2007 ~=2 L!-;_;19ilJ _ _/ _____ l '~ill~~ I; .r--· 1r~-[!f\_1_· .. "'111ULStresLi i Li ·11 r':f I iF ---L---_J I l ' !-t--- , / ------1_ I /•, ._' -1------.L I : --- 1 ·1~---,: ~~ . I " ·-= -----'--~ -~![1t 1-1 -"·-t. -__ -_ n=fF1rr1 i~ \ Legend D RID [_'_'_'.=-J Basin Boundary o Type 2 CB o Type 1 CB --Pipe/Culvert / / - 1 I --~ -.·, ·----~f 1c1-r---~::1 t~ \ ~ ' --r-:rr I ~H±r [ Ir I / /". -I L/, ------ 1 n-1 f1~1il;~---~ r~1,_\r~c1 rrrfl~~~b ~Y4~-~} ~-~ i --- C244 .. . , ' '·.J r1· YT.-Y1-J1.L1-il 1l1 -·--rl· ~ < _ ----•··.---'1--............... s-.. -.. ·.·.~.1 .... ·J .. , ·J·.1 1. 1_J .. 1.1 1·--'-- '~""/_J._ -L--: __:J__'-1_ '! ------.l__ -I -.J::::.. l l [ 1 I I ,~----L_r ____ J__r -lt---I c-260] . I . ·._ . I 1 :>! 1 _ _ __ , o._ l , ::J I I ,---'cc_ ------""'---~---\ __ I. ]1\.J C-304 ,···--I -1......---r- fC ~.; J-;: ~>Sil --1 r ~ 1 !. · ~· · •·f-. ..__ _ ~ I<•>, _-· , t-· i·J:d-'--:i---:-~l · I , . ~ --~ pc· -rt,--r:-+ ~ ,~ -:-===7 .. •-~·.:. ~ '.;_-;:!d Ws----. . L ~v-. .. ·, ~~berty_Groy~_. , "' . --lJJ ,\..-nr-r:c'.:_J . . ·11 J ·-c:i.---.-~ .. -"".~. 11. ·.-. ' ' . . ... . ~~. ··1 . j<•. · •. >.Jil·t=::':J.· .·,·· C-120. cce. · · 1 L~ __ --·_i-· j-i Ii'~-. · · ----~ ,-~__. -: - I r-----------::'cl I k_J · g~5;;\,.{; I , , ' j /J . [---- , ' I ,, . . --·---/ : ___ .. [l=ifT 0TT'l -~ : . -, . ·-. ..re:' ~~----1 , __ _:::_ __ 1 _ _ :_ , J .. c.L_LLLJ-t · . .· · , ! ~-/,····.~~ .r~--.' l. 11·f·r.if]~.<~·>.1: .. : :· ~.-r c-~2: ·(·1[ . I . .. : '"'--~---·--· '-""'"" • -. , Cavelia j C-320 I ~ _J. I · ··. ·. · .. · .. ··-f ·· ··.· · ...•. ! ·J > .... ·-.. ·· -_ : -t~1 ----~_ ; I· · . . -... '-. -.. --. LJ .. · ·· · .. · ..... ._.: •. :~.· ·.-,: ·.. . \ j 1 1 • . -. 1 ,-J-crrrn ·.· .. · > --,,~\-_-\ --J 1--~ ~-... -· . -. . . -~LLl.lu:."J ~)c..,_.cc-..::.__ -1 --'.\~~~ I •. ··•. ~~i.__ · . 1 . . .. _ ·-· _ · . J . , ....... · .. r 1 \ \ C-300 . _ . • 1 .... ,..___ -----,.. --:-i i--.. ---_J .. -J , C-110 I ·-=-,-~... T---i \ r . ,. i ' ~--E-'.~-f ·Ir _>:\~:~~L .. ~ ~·r~ C-2;0 I\ \ .. ,~., 1 ·· .. ' I C-3~~ I f .:· \ .... r [ ... -c· -a, . .. ·. , -,:.•••.· .• ·' -<. L-'" -. .-~ -.. -.. :~-~\~'•f't,; .-.. · -li-be~Gar-de-~s : ~~'-·:-.. --J·• .. 'L '<·-:-'-'--. > ·. I <i:J -~ . . ..... , \ I ''\ : .. . . _··~ .· -···-.,,.., :~ .~-~~\<~,:;·: .·· .. ·.. ---. -~,,,,F_?:. , ': 1 · ··;~:i~~:-.. ::. >'.\ --. ·•·· ·.-····-·-.. · .• · .... ·.-. -) . 25-YR= 8.36 CFS ~ --. -• -':-5~1,_ / . , ! . ·. l·~. 1·c· . ----r: ··,:-. l'r ;:~ /~_l_ _ : : ~-J_DL1J L~-~~-[L ;. . ::.};_~,c_ .• ·.') : A .•. ~~~; .t :>-100-YR=10.86CFS , :__ ~ C:a,p~j. _-·;··· . .C:. C-44 "--:_ cc .._ -~f-, : , \,.\_'···.· -... , ···· .. ->,··· ...... ~·.~.-... ·t .. ·· .. ···.··.1. ·.·.·.:,:-. ........ 1 }.Jl: ·:.·· .. , I A I C 100 '=* -i---r--:-i---. . C-52 ' -.. -'-'•': .:. : ..• ,;,, . <· ' C-70 . .. I I . J \>{,e-r /[ -~.. lrfy 25-YR = 22.23 CFS I -T I 1-' . • ..... .:-_. / . zl:,• .. ·.·.· ... -... ··· . .····.··:,/. '. ' \J .. _ -· _LJ _1 1 1. 100-YR=24.66CF~ 11 • 1 1---1 1 .1 1- -----..,,... .. b-_L:,¢7:::-~~,c;: King County, Washington [ ---, -,:, I ("\ , • ,·/ "--- 0 .__ ___ __.Feet Ed McCarthy, PE, PS 9957171st Avenue SE Renton, Washington 98059 Phone: (425) 271-5734 Fax: (425) 271-3432 Date: 6/15/07 Figure 4 Catchment C-106. The stage-storage relationships for these stormwater ponds are listed in Appendix B.2. Peak flow rates for the 25-year and 100-year return periods at key locations in the watershed and along SE 144th Street are shown in Figure 4. The peak rates associated with the 2-, I 0-, 25-, and JOO-year return periods at these same locations are listed in Table 2. The major inflow points to the SE 144th Street conveyance system are at the intersections of 162nd Avenue SE and 156th Avenue SE. A total 100-year flow rate of39.72 cubic feet per second was predicted to flow to SE 144th Street from contributing basins. 2.3 Hydraulic Aualysis of Conveyance System The conveyance system along SE 144th Street consists primarily of an 18-inch diameter CMP located along the south side of the road. A ditch and culvert system is located on the north side of the road. The ditch and culvert system is not continuous along the entire length of SE 144 th Street. Rather, it is broken up by segments of road with no conveyance on the north side of the road. The northerly ditch and culverts are connected to the 18-inch diameter storm pipe by 12- inch diameter cross culverts at four locations along the conveyance route. At 156th Avenue SE (CB-6), the diameter of the pipe system increase to 24 inches. From CB 6, the pipe system continues west in the unimproved SE 144th Street right-of-way. At CB I, the pipe is conveyed down a steep embankment to 154th Place SE and then to an HOPE tightline down the steep ravine slope to Tributary 0307 (King County Department of Public Works, June 23, 1997). A detailed field survey of the entire pipe and ditch network, including several road sections, was conducted by Barghausen Consulting Engineers (June 2007). These data were used to construct the XP-Storm and HEC-RAS models described below. The hydraulic model XP-Storm (Version 9) was used to evaluate the 18-inch diameter pipe conveyance system along the south side of SE 144th Street. The EXTRAN layer of the model was utilized, basing hydrologic inputs on flow rates predicted by KCRTS. The XP-Storm Hydraulics engine solves the complete St. Venant dynamic flow equations for gradually varied, one dimensional, unsteady flow throughout the drainage network. The calculation accurately models backwater effects, flow reversal, surcharging, and pressure flow. The model allows for looped networks, multiple outfalls and accounts for storage in conduits. The XP-Storm model accounts for pipe friction losses and pipe entrance and exit losses. A Manning's roughness coefficient of0.024 was assumed in the modeling for CMP and a value of 0.012 was assumed for concrete and plastic pipe. An entrance coefficient of0.5 and an exit coefficient of 1.0 were used at catch basin junction. XP-Storm modeling results for the 25-year peak flow rate for the conveyance pipe along SE 144th Street is provided in Appendix C. 2-7 SE 14,f Street-June 2007 Table 2. Peak Flow Rates at Key Locations Location Return Period <Years) 2-Yr(CFS) IO-Yr (CFS) 25-Yr <CFS) 100-Yr(CFS) CB-18A 9.86 15.70 19.08 24.66 160'" Ave SE 11.23 17.65 21.31 27.42 CB-5 11.72 18.37 22.23 28.52 CB-4C 4.25 6.86 8.36 10.86 CB-4 16.09 25.43 30.85 39.72 The hydraulic model HEC-RAS was used to model the roadway surface and ditch conveyance under flood conditions for the I 00-year peak flow rate. The I 00-year peak rate assumes that 5 cubic feet per second is conveyed in the 18-inch diameter storm pipe along the south side of the road. The remainder of the flow is assumed to be conveyed in the roadway and roadside ditch. The roadway conveyance capacity was evaluated from CB-I IA (HEC-RAS Sta 0+00) to the intersection of 162"d Avenue SE (HEC-RAS Sta !o+IO). HEC-RAS analysis of the roadwal conveyance system for the I 00-year peak rate indicates that the ditch system between 162" Avenue SE and 160th Avenue SE has adequate capacity to convey the JOO-year peak rate. However, driveway culverts along this reach would be overtopped. In addition, the HEC-RAS model predicted that flow depths would be up to 0.7-foot deep over driveways. HEC-RAS results are presented in Appendix D. Roadway flooding along SE 144th Street would be considered as "severe roadway flooding problem" according to King County standards (King County Department of Natural Resources, January 2005) due to the following conditions: • Between the intersection of 162nd Avenue SE and 1601h Avenue SE driveway culverts along the ditch on the north side of SE 144th Street·would become overtopped, posing a threat of unsafe access due to indiscernible driveway edges. • Floodwater over the driveways on the north side of SE 144th Street between 160th Avenue SE and CB-I IA would be deeper than 0.5 foot, posing a severe impediment to emergency vehicle access. 2.4 Flooding Locations and Flood Flow Paths Flows with return periods of 2 to 5 years likely surcharge the 18-inch diameter pipe system. Flows were predicted to leave the pipe and ditch drainage system at a number oflocations including CB-4C, CB-JOA, CB14A, CB-15A, CB-15A-1, and CB-18A. Between the intersection of 162"d A venue SE and 1601h A venue SE, overflow from the catch basins is conveyed to the west in the roadside ditch on the north side of the road. From the intersection at 160th A venue SE, overflow from the catch basins is conveyed to the west mainly along the north side of the road. Flooding covers the north half of the north travel lane at locations near CB-I IA. From CB- I IA, floodwater is conveyed further west in the north travel lane until it reaches a low lying area located north ofCB-9A. Depending upon the magnitude of flows, the floodwater either 2-8 SE 14.f' Street-June 2007 C _________ ! _, Legend ifl __ L r / 1 i 1 --~ ·1 1 l -l\ 1 1 11--------------,-T---,--I_J I r \\ -'t· i I f I I I l I I i -. : /~ I I I ' i I I ' \ ' ___ , I j I •, ------1 -I, 1 ' -- CJ RID r··--···--. [. _______ .i Basin Boundary ~ Flood Flow Path I! Lll I I I I 'I '\ \ ' 1, I ' --I I 1 I ,--1' 1 r--~-1 1-1 --I \\ -\\, C-300 , -----i !===·=· =-· f I! f ~ ,'---1-----, \ ~--, ! I ~ /_ 1__ j j I \ \ 0 Type 2 CB D Type 1 CB i I I I I I I '\ \_ I --1 / I 1-----'r-----LJ --d rB1 . ---, ___ '·-,_ -I I J -_ J I I r i .1-= I -\---~~ i-------- 1,--t 1 / I ~1---------\ ·t,_ i --J---. I I ,_---Ir,, -!I ---------,____ .\ --,-.,_\ 12-18" Pipe/Culvert 24" Pipe/Culvert I C-10 i Basin ID )--w 1 1· j I -~'1-\ \_ ----:. w I -~ \ \ J I . /'------1 i r------+--1------=-T~-_ re- 1 I \. \ 1 ·\ ------~-·/_ = -I /' -1 I \ \. I I ,, ~~ ._ _ -----------1 \ \ _ _ _ >' -_ lll I _ _ \-------~--···-----_ --- 1 -I -------\ \ I \, / ' I ~ I I' ·-"·--·-·---_--~\~\ -\ µ/;\/ -·1 ---// 1 --1 T 1 / _-/7 ~/ .. I 1 f I __ I ' \ __ ------_)>---~1/l I /-/ , f -n~1-L / 1,J /// r:=:h 1 1 L \_----~ 1 1 1 r i 1 1 ·-...;. _____ ./ C-44 1 --__{______ --/ --~ i L--,.----~ -:r------~, ! l I i 10·· II II 1 _, I -I I -Ii --/-/ ---1 ' r I l v· --7 / , : ' 1 I ·' , · , ~ J c. '"' 11 I , / 1 _ ·: , , : _/ ---· CEl-4B ~-<-; I ~ [ .-I \ --1 · / / 1 A-/, ~ I j --1 ·, C-52 \ J_ ~' Ii ,: , 1 ~ r-+--i I I -Likely Flood Area / I "----/ '\, • '-..g i j t ', ,,, " I' r i : I and Flowpath I I ·---' ,,/ I i ' I', ,1, '' I I \ -C 54 ' 11 ' i·li. !) :;') CB-4A ' \ I . I ·,.-( \ ''!'' --c/N I I ---I-I -' /./ / \ \ i I \ i I i .. ,/··· -\-> ·r-b-[/ l , I -" r-1 ~ , •I U c_:'.__:,"::, __ ~-_ j lJ [ · ' 1 __ -, CB-'1M r __ ,B'i_<f}-S t_:'~~1'1_.~-~-_, ___ -_ r -c.1 :'._\ c~ /-fcB-71_1 °ii. : ;ii'. f°"' CB-IO f'"" Vca1,;1CB-'1r c~·; I ;_, -=-:::::-.. CB~16···-···_ -.::_ ' ____ r-_ ;_-:--1;t~11·_--·1ci·rs·~_r-·---~,-9-:_ ''"'' ~\•'0'-\';, 'i•"'-'C• I • .-----.. • • T ' i ' ·. . , I ' r /, :w,"'"'"" "·""%.. I : l,~·r ,---,----,--~ -~--~-;··---: -' l ! i' ~th St,/ : 'C-SO I __ )1 1---· -_ -__ c_ __ F'--. ~ I -,/ -' I -I: I I ---_ / ' ' ' ''y --~ I-I rl ~--_J LJ, r·-= --_ /' L -[_--.---____ ,-ULli / \'I \ /lll-_j ___ . I --//,\·y~-c...:,-··\\I I I ' ' i -, ' :_ ! ' I / / ,', --/ /-, '_ \ ' --·-it'''"'i:\\\'ic"' ''-'-'•':\\,\'')";'".\ ---l1t}\'lit, I I ~-i -I -_ ------. --------II I '( ;------.c I/ / -,,, \ ,;};*'\/%\Tuft~~}\;-··-.}·":/?<:": -S-}S.> \ ";Xj}t~?-1fitt-~----· I I / 1 / ) tls.l\t\1\~'t1sWtt~ic\'•,>->iis}\ _ -f\"liFJ/¥.)'it, r I -· -, , , / , /',, "<v// -•:-1'0?-,\ti\ii/t,<ii},:->>:-?•.c\';\s-,, \ ' •%/{~'f;_'s'i,I•_ ---1-I -I I I I : I .' / ' ." '111L.~~ 1 ·1 L--J L ·., -i r--"' Ii 11J~l : ~/ e "' la ~ 0 0 N II) I!! ::I Cl i.i: ;i i:j ~~ ~~ ~~ ~~ "' I~ ~ w~ "'m :g § C "' ~~ ;, !l' ~ C -B ~& -Q) Q) u. 0 E .!!l GI "' ->, UI ->, g! en ci: C GI a, i (J 0, C g! C i: cu ·-"' >, ~ "' GI Cl 5 > :i, C 0 C (.) -a, ::, 0 .. ~ 0 0, en en ~ ..c J:: --; ;g: ... -WW en en ---·----r----~. ·-----7/. ·1' ~"'"",--.:--·· --: I . . , ___ _,_ -J I I I I I I I I; i ///11 I --T"'-T\,~ " I I '• ,,,o -~-~ I I : I ' I ' ' ! I ' : ·1· I I I I . ' / i I I ', i I. ·.; . 1 C e ----i ' • • , i I / I ' ' ' 'w ' -Option -onveyanc B-4B~: 1 -es--4eJ-_____ , _____ J_ -··--'------; -~-_J ____ ------~.'------'-...../ .. -! _____ ,_j ___ J ____ J __ L __ ~_ i(/).gi 1 1 / I -----=----....J I I :c: / / . . -,/ ··-·--··1--------1------·-------.i. ------1 --------···--·:------,r--~··-<___ . k. \ l 111 i ,/ .r .. l/--· ,---7--·----~ I . i I r i , \ -, --... ,___ .. ---,,, 1· // !, ,. r-· 1 ru , . I I I . ! I "· -"' ' C" ,,,. .. . .1: ! p ' i I i ' 1 . I I Ditch/Culvert ;N · ·, '; ii ! i CB-4A '/6 I I , i , I I 18" Conveyance I ' · If!', , __ ,VJ ·,ril ! I ~ r---11' I ~----------------r-!---;---i -Pipe ~--)--I ~pgral des i' i \ \ i ! i I / \ -t 't '.· C~-1 CB-2 CB-3 i ~ ' I I LI :I I i : I. I I ls-110 'I CB-15AI I I ' r . \ 1 1 I r ' I ' . i I I 1 ' CB-11 c ' ·~~ : ______________ ·----·· ___ ___ _ I_ ! _______________ _,_ ___ _J____\, __ _ I ---,------ _1-' ! -I csf ts-a!---~'e~Yl _c_'=s--:,_~-~ ?c-s=e--f~ CB--1~-~---(CB-1'f-c_-=-rrcst12lcs~1 C 1~1ips21I-.--:::--=cB-16 SE~44thsfl1 ffs~11Tcs-is-. 1 ,----:-~B-19 0/ /-r--., 'JI --·,II -_I I i ,: ~r~=:~ ---~ f ____ -_'j ' 1--~--~~---.!' ~-_;_jl ·111 ·, I ' -r · ,! vi· \t::-:c f ,--i I/ 1 f 42 \ i I\ I \ >-------~-=-)'-..\. I ;_ 1----"--I 11 I --:,1 : : ' I! I. 1 I / I '-. X ~ , -/ ~ I ~-·-j, L.. ' ~.:;;.""'~~~i.i:;;:c:....===~-__ .... ______ . . - -- / I / .. ,.··-;. )1 '·. / ' ' \ I .. ' . . I CB-48 ~.· .. B-4 -I -er L__ -)-,.,_ I --, I J / I '1 ' ! 1 '\ -'~/ / 1,···ir··· r--l-.. -.. _L _________ , ____ J_ ____ ilf ·-.. ---_J_ ------~· I L_ ; I I \ : ~ / Op .. ~.t.i~.·.,·"·:·.···.2.· .. · -Conveyan··.ce./lnf•i .. ltration I ' . c- 1 'Ii ---~I! ---I 1-i --I l--T---,11---.....,__I z --)~ Lrl :~--~:-' \~-: -~ ij f /) • , / 1 lnf1ltrat1on ' " -1 ', ;-_..)-----11 ,,, ,,/ ' I I nd ~ '--/,. "',,., ! C ,,_... \ I .. i ___ , ___ J_ __ , Po J 18"Conveyance > 1 I / iN ·· \\ 1 'f'::r \':,·. ·.; i: •'• ... ,' 'e' ..• i 12"0verflow I . .vi' I ·T .. 1 Pipe -!:i;. __ _}--~1 Ditch/Cul\ ' .. ~ ~ e "' ~ $ rn 0 • ',,j \ / C~-1 CB-2 CB-3 ! Pipe ~ 1 > . ,( I / · 1 · t , ~ f f Upgrades I I i j t. \J L I "" l 1 :;:;•> .. 1 1 !s-110,.. cs-1sAf i ; 1 1 • , .J..., V V > -'O:: i -._:, _J_____, I I I C -11C,.;;-""-'~' .. 1 ·. : i ! I :&8:%~, /""",":;~'0*" __. -, '\ x ~ ---f / CB-18A o .:~~:,~""~ ~-:~;-_\ f\~\»k I "' ) cs.... --L1 ~ a ..._...,~ ~'\."\'i :,\. ) ".:: ~<;:,.'S, X • ,-' --' ., " ~~ :-..BF',\~:-..:::_ ~-ff:%, -:::· ~/ ' CB-€ __ Jc9-7 CEf:fr 1 )1,, (CB~9 -.._ ~ .,"( _.> .. --., 1 J// , "' /_____. ___. "\ N <O a, ... ::J .!? LL ,i ;:j ~~ ";> '? ;::.. ;:: ~~ ~~ y, '.':!- • C .. 0 X tf. !I'. !1l W 00 w~ §! <l) .!a: i1 ,;; J!i i ~ ,:£ ~ " si & al (l) u.. ,- • "0~ SIC\ '''\ B ---..~ - . c0l'C<;::-.. ,1:zi'*-\t\. (~~:\ r------' ,.---I '-i 'I I O 1 CIHIJ \1.··(CB-11 \H,· c_er12 _lc.B-\J,B CE~) :B-i,J/ CB-16 1SE144th1t\ f,.,_.B-17 /CB-18, ' ,1 EB-19 G c-\~~%~~~\ ·,,-"l\if~i' '\, ' .. _ .. -----, __ , ' r--\ lj / ,.... ',' \ I, ! I )' ) .... '\ I """:-s--'lllf~'\, .. ~-. , , , --\ , -,~, ,:/(·:11 , --Ii. /---~/111\ I) ;-~\\/ ,~)~', --, ______ ·,1 , !11/ ,---~ rt r~_ '·. I L lil\~-"R.' · I_,' I C ' <I , _ k~ -, ' '•• ILLI-' ' · · --/ --\ ' '_ 1 I 'vi ' :. ' '-[ , -~-. -1 I , ·1· .j_J···.·1·7·"·.·.-.·.-.·.·_ .. · .• ·"--~--. '. , .. \., I . I . . .. .· .. .· ' I ' l ·.. I /I ' ~········.·· ·.· .. I ,,i \ ,, .-.. · ,1 i ) ~. ·, . ' ' -.··•·· ' > : -~. : t \ i~I; / I ......, "' ., ;. A.~:w~c,," -di. I r· . I •• • --\ • • .: ••• i .. "'· ·. ,' .. · ' I / )$u , 1 1 i"', , . · .I . · I w · ; ~ --·. / I 'CI I L~1' ·, \I.~./ I, W·· • ... · ··.· Cl)· .·· i:--:-.. · · ) ' .... '/ /'y''/ / -.--------,, \ /~l;j / "-,,J (I). . s·1oretent·1on ha" Dia ·· ·. · '-. m · ··· · ~---\ ·, · ! ~-·-.. ,/ 1 (;j} -/ .. 6 ""',, C.,0-N""""""" """', I _ LJ-~ , Y -!i 1 ,,...-\ \ 1"/ CD • ::S / 1 ,,/ . \], 1>1! \\\ / : 1,~ g? · and Overflow • _ I\ T· ·1 . .n· · . . .·· ~ ~ '1 i~ . . <( " J.,, . I . l ,f , c, -1 cs-2 ,s I · . -I . . a . . . .. · .! 1 CB- 3 illl CB-I I ~ 1 · ' i:110 ~. CB-15A I I •. ii' ~T"I,, '~'-'I' P''-'' ~i-,..._ ·o· ""--....... ~ . ....-.,~ " ,") .,. "· -~ = '---(;' -~ -,/ -;,:~ _,. ' CB -"""' ' ,· ·=.---, c CB-18A . ~ ' ........,\ ----. I h ' ·~ -' \ ' '-. "'_\ C.tt1 , 7 t.B - 1 1/'·_________.. -CB-16 l. E 1i~')t:J-17 ~B-~l' /;, r-1'97 ( I,-' ' I .-I--" I ! ' -.., I I { \ -~ / l -. ;....--------. \ / __ / --~I -_--.... Q'v" CB-~. -----CB-tlJ'·. . / CBc 11\ 6 ,.J ! I \ . X ----....., , I (( r:111 , "-' ,r----·,;J CB-E jea-7 CEf-8 3/~2 CB-v \ )· \n \ ' .c'.=-----',J\ \ U) -~ s::::~ 0 "' •-C -<( C a. " .8 0 g, 0, C CS :c "' 0 ['! "' ·-0 ;;: -Ill .i-.~ C :, :!:: -0 ~~ 0 Q) iii 0, C -.c 2 ·--~! Qw Cl) Similar to the pipe system on the south side of the road, the possibility of including sections of perforated pipe embedded in drain rock on the north side of the road should be investigated. Issues such as the impact of infiltrated water on the structural integrity of the road base and surrounding properties should be evaluated by a geotechnical engineer. 3.3 Offsite Conveyance Improvements/Infiltration As with Option 1, offsite mitigation Option 2 would include improving the conveyance system along the north side of SE 1441h Street. Between 162nd Avenue SE and 1601h Avenue SE this would entail upsizing driveway culverts and re-grading and cleaning open sections of the existing roadside ditch. From 160 1h Avenue SE, an 18-inch diameter storm pipe would be constructed to convey stormwater to an infiltration pond located about 600 feet west of 160th Avenue SE. An overflow structure from the pond would tie into the existing 18-inch diameter storm pipe on the south side of SE 144th Street. The proposed location of the infiltration pond is a large lot with a smaller single-family residential structure on it. The lot could perhaps be subdivided with the vacant tract being purchased by the County. The pond site is likely within the current flood flow path oflarger storms (Figure 5). The infiltration characteristics of the pond site are likely favorable, as has been noted with the successful operation of the pond at Carolwood for several years. The infiltration pond would take advantage of the high infiltration rates of the underlying outwash soils and would reduce the flow rates to the storm pipe downstream from the pond. Environmental benefits of the system would include improving water quality and increasing groundwater recharge to the benefit of down gradient tributaries of the Cedar River. 3.4 Bioretention along SE 144 1 • Street Offsite mitigation Option 3 would entail constructing bioretention swales within the right-of-way along the north side of SE 144th Street (Figure 6). Bioretention is a commonly applied low impact development (LID) strategy that has also been used with great success in improving roadway drainage in established neighborhoods. Seattle's Soft Edge Alternative streets (SEA- streets) have been shown to substantially reduce stormwater runoff and improve neighborhood aesthetics. To manage stormwater nmoff along SE 1441h Street, a series ofbioretention cells would be constructed in place of the existing northerly ditch and culvert system. Each bioretention system would be configured with an engineered soil media, a gravel infiltration trench, an overflow control, and a conveyance pipe/driveway culvert linking the cells together. In addition, each cell would be landscape with native plants. The bioretention cells would take advantage of the high infiltration rates of the underlying outwash soils and would also increase conveyance capacity for higher flow rates. Environmental benefits of the system would include improving water quality and increasing groundwater 3-3 SE 144"' Street-June 2007 recharge to the benefit of down gradient tributaries of the Cedar River. In addition, the bioretention cells would improve the aesthetics of the neighborhood and also provide shade. Disadvantages of the bioretention system would include disrupting existing landscaping of property owners and reducing street parking. 3-4 SE J 4,f' Street-June 2007 4. KEY RESULTS AND RECOMMENDATIONS 4.1 Key Results The following conclusions can be drawn based on the hydrologic and hydraulic analysis conducted for the conveyance system along SE 144th Street presented in the preceding sections of this report: • The three proposed developments (Threadgill Plat, Liberty Gardens, and Cave Ila) collectively represent IO percent of the study area basin. • While calculations presented in this report suggest that the conveyance system along SE 1441h Street is undersized, there are no drainage complaints on record that support this. Physical evidence of flooding has been documented at the intersection of l 62"d A venue SE and SE 144th. Drainage improvements have also recently been constructed by King County Roads Division at the intersection of 160th A venue SE and SE 144 th Street, likely in attempt to collect overflow from the catch basins at that location. • The 18-inch diameter pipe along SE 1441h Street has a capacity of 4 to 6 cubic feet per second. The roadway and ditch system along the north side of the road convey the majority of higher flows. • HEC-RAS analysis of the roadway conveyance system for the 100-year peak rate indicates that the ditch system between l 62"d A venue SE and 160th A venue SE has adequate capacity to convey the 100-year peak rate. However, driveway culverts along this reach would be overtopped. • Flows with return periods of2 to 5 years likely surcharge the 18-inch diameter pipe system and flood the intersection of 1601h Avenue SE and SE 144 1h Street. Overflow from the catch basins is likely conveyed in the roadway until it reaches a low lying area located north of CB 9. Depending upon the magnitude of flows, the floodwater either infiltrates at this location outside the road right-of-way or continues to flow to the Carolwood infiltration pond. • Four flood mitigation concepts were presented and discussed including increased onsite detention and three offsite mitigation options. 4.2 Recommendations Any one of the four proposed drainage mitigations would adequately meet the intent of the King County Surface Water Design Manual (January 2005) Core Requirements. Offsite mitigation Options 2 and 3 would provide the most benefit to the downstream system in terms of stormwater management and environmental advantages. While onsite stormwater mitigation would perhaps the easiest and least expensive option to implement, the downstream flooding problem would not be solved. 4-1 SE J4,¢h Street-June 1007 Implementing the offsite mitigations would require King County's leadership, and even ownership of the project. This would be especially true for offsite Options 2 and 3, where a vacant parcel would need to be acquired (for Option 2) or the right-of-way would need to be substantially re-graded (for Option 3). For any of the offsite options to be adopted, the County would need to see value in solving drainage problems along SE 144th Street and in the environmental benefits provided by these designs. Providing bioretention through SEA-streets and the like, to solve existing and potential future drainage problems, should be a consideration for the County. To my knowledge, the County has not implemented a project similar to Option 3, and this would be a suitably-scaled pilot project. For these offsite options to be implemented, each developer would likely make a fair and reasonable contribution to the project. The County would be responsible for designing and implementing the project. 4-2 SE 144° Stree1~June 2007 5. REFERENCES Baima & Holmberg, Inc. and Ed McCarthy, PE, PS. November 18, 2005. Level 1 Downstream Drainage Analysis for Threadgill Plat. Issaquah, Wash. Barghausen Consulting Engineers, June 2003. Hamilton Place -Technical information Report. Kent, Wash. Daley-Morrow-Poblete, Inc., February 2003. Liberty Grove -Technical Information Report. French, Richard, H., 1985. Open-Channel Hydraulics. McGraw-Hill Book Company. New York. Haozous Engineering, PS. May 2003. Nichol's Place -Preliminary Technical Information Report. Mukilteo, Wash. Haozous Engineering, PS. June 15, 2001. Evende/1 Plat -Preliminary Technical Information Report. DDES File No. L98P0047. Renton, Wash. King County Department of Natural Resources, 1997. Lower Cedar River Basin and Nonpoint Pollution Action Plan. Seattle. King County Department of Natural Resources, 1993. Current & Future Conditions Report for the Cedar River. Seattle. King County Department of Parks, Plarming, and Resources, 1990. Sensitive Areas Map Folio. Seattle. King Counz Department of Public Works, January 18, 1984. SE 144th Street-156'h Ave. SE to 1641 Pl SE. Sheets I -8. Seattle. King County Department of Public Works, June 23, 1997.1541h Place SE Slope Stabilization Project. Sheets 1 -13. Seattle. King County Department of Natural Resources, January 2005. King County Surface Water Design Manual. Seattle. U.S. Department of Agriculture, Soil Conservation Service, 1973. Sail Survey a/King County Area, Washington. 5-1 SE 144"' Street~ June 2007 Appendices Appendix A. Photographs of the Downstream System Appendix B. KCRTS Documentation for Contributing Basins Appendix C. XP-SWMM Model Results Appendix D. HEC-RAS Analysis of Roadway Conveyance SE 144'1' Street -June 2007 Appendix A. Photographs of the Downstream System SE I 4.(1' Street -June 2007 Appendix A: Photos of the Downstream System T Photo Number I T Photo Number 2 Date of Photo: 1-11-06 (Source: Dave Petrie) Date of Photo: 1-21-06 (Source: Dave Petrie) Location: South of CB 18A, looking north. Location: North of CB ISA, lookin~ south. Description: Overflowing pond during height of rainstorm. Description: Pond north of SE 144~ Street within the 162"" Water is flowing to the roadside ditch on the north side of SE 144th Street. right-of-way during a light storm. Appendix B. KCRTS Documentation for Contributing Basins Appendix B.1 KCRTS Time Series Calculations Appendix B.2 KCRTS Pond Designs Appendix B.3 KCRTS Peak Flow Rates B-1 SE 144'1' Street-June 2007 Appendix B.1. KCRTS Time Series Calculations KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-10.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STOP60H.rnf Outwash Pasture 0.16 acres Loading Time Series File:C:\KC SWOM\KC DATA\STOG60H.rnf Outwash Grass 0.29 acres Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 0.08 acres Total Area 0.53 acres Peak Discharge: 0.071 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File;c-10.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow ·Frequency Analysis Loading Stage/Discharge curve:c-10.tsf LogPearson III Coefficients Time Series File:c-10.tsf Project Location:Sea-Tac Mean= -1.641 StdDev= 0.141 Skew= 1.196 Frequencies & Peaks saved to File:c-10.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-10.tsf Computing Interval Locations Computing Flow Durations SE 14.f' S1ree1-June 2007 Durations & Exceedence Probabilities to File:c-10.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series B-2 Project Location: Sea-Tac Computing Series c-20.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf Outwash Pasture 0.30 acres Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 1.05 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.51 acres Total Area 1.86 acres Peak Discharge: 0.331 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-20.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-20.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-20.tsf Project Location:Sea-Tac Mean= -0.857 StdDev= 0.119 Skew= 0.941 Frequencies & Peaks saved to File:c-20.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-20.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-20.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-30.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.31 acres Outwash Pasture Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf B-3 SE 144"' Street-June 2007 Outwash Grass Impervious 0.91 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.41 acres Total Area 1.63 acres Peak Discharge: 0.276 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-30.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-30.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-30.tsf Project Location:Sea-Tac Mean= -0.949 StdDev= 0.121 Skew= 0.973 Frequencies & Peaks saved to File:c-30.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-30.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-30.dur Project Location: Computing Series Regional Scale Factor: Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production Sea-Tac c-40.tsf 1. 00 of Runoff Time Series Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf Outwash Grass 0.26 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.30 acres Total Area 0.56 acres Peak Discharge: 0.145 CFS at 16:00 on Mar 3 in 1950 SE 14(" Street-June 2007 Storing Time Series File:c-40.tsf Time Series Computed KCRTS Command B-4 Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-40.tsf Project Location:Sea-Tac Loading Stage/Discharge curve:c-40.tsf LogPearson III Coefficients Mean--1.104 StdDev-0.105 Skew-0.664 Frequencies & Peaks saved to File:c-40.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-40.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-40.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series of Runoff Time Series Project Location ; Computing Series Regional Scale Factor : Production Sea-Tac c-42.tsf 1. 00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC DATA\STOP60H.rnf Outwash Pasture 0.03 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf Outwash Grass 0.96 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf Impervious O. 67 acres Total Area 1.66 acres Peak Discharge: 0.373 CFS at 16:00 on Mar 3 in 1950 SE 144"' StreeJ-June 1007 Storing Time Series File:c-42.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies B-5 Flow Frequency Analysis Loading Stage/Discharge curve:c-42.tsf LogPearson III Coefficients Time Series File:c-42.tsf Project Location:Sea-Tac Mean--0.747 StdDev-0.110 Skew-0.794 Frequencies & Peaks saved to File:c-42.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-42.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities. to File:c-42.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-44.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf Impervious 0.99 acres Total Area 0.99 acres Peak Discharge: 0.408 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-44.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-44.tsf LogPearson III Coefficients Time Series File:c-44.tsf Project Location:Sea-Tac Mean--0.596 StdDev-0.096 Skew-0. 562 Frequencies & Peaks saved to File:c-44~pks Analysis Tools Conunand Compute Flow DURATION and Exceedence Loading Time Series File:c-44.tsf B-6 SEU(" Street-June 2007 Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-44.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series of Runoff Time Series Project Location: Production Sea-Tac c-50.tsf 1. 00 Computing Series Regional Scale Factor : Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC DATA\STEI60H.rnf Impervious 0.51 acres Total Area 0.51 acres Peak Discharge: 0.210 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-50.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-50.tsf LogPearson III Coefficients Time Series File:c-50.tsf Project Location:Sea-Tac Mean--0.884 StdDev-0.095 Skew-0.562 Frequencies & Peaks saved to File:c-50.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-50.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-50.dur SE 144'1' Street-June 2007 Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series B-7 Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-52.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf Till Pasture O. 01 acres Till Grass Outwash Pastuie Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.80 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STOP60H.rnf 0.01 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 0.80 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.15 acres Total Area 2.77 acres Peak Discharge: 0.701 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-52.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-52.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-52.tsf Project Location:Sea-Tac Mean--0.457 StdDev-0.118 Skew-0.538 Frequencies & Peaks saved to File:c-52.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-52.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-52.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series : c-54.tsf B-8 SE 14.fh Street-June 2007 Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf 0.03 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.03 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.83 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOF60H.rnf 0.04 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.04 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 1.24 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.44 acres Total Area 3.65 acres Peak Discharge: 0.876 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-54.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-54.tsf LogPearson III Coefficients Time Series File:c-54.tsf Project Location:Sea-Tac Mean--0.367 StdDev-0.117 Skew-0. 588 Frequencies & Peaks saved to File:c-54.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-54.tsf Durations & Exceedence Probabilities to File:c-54.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : c-60.tsf B-9 SE J4¢h Street~June 2007 Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf Impervious 0.52 acres Total Area 0.52 acres Peak Discharge: 0.214 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-60.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-60.tsf Project Location:Sea-Tac Loading Stage/Discharge curve:c-60.tsf LogPearson III Coefficients Mean~ -0.876 StdDev~ 0.096 Skew~ 0.561 Frequencies & Peaks saved to File:c-60.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-60.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-60.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-70.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Pasture Till Grass Outwash Pasture Outwash Grass SE 14<f Street~June 2007 Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.51 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 1.70 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.34 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf 1.13 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf B-10 Impervious 1.34 acres Total Area 5.02 acres Peak Discharge: 1.06 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-70.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-70.tsf LogPearson III Coefficients Time Series File:c-70.tsf Project Location:Sea-Tac Mean= -0.327 StdDev= 0.133 Skew= 0.509 Frequencies & Peaks saved to File:c-70.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-70.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-70.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-80.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass SE 144'1' Street-June 2007 Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf 5.28 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.12 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 4.35 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOF60H.rnf 0.59 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOP60H.rnf 0.01 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf 0.48 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf B-11 Impervious 3.40 acres Total Area 14.23 acres Peak Discharge: 2.61 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File;c-80.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-80.tsf LogPearson III Coefficients Time Series File:c-80.tsf Project Location:Sea-Tac Mean= 0.090 StdDev~ 0.131 Skew-0. 500 Frequencies & Peaks saved to File:c-80.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-80.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-80.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-90.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0. 40 acres Total Area 0.40 acres Peak Discharge: 0.165 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-90.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module B-12 SE 144'~ Street-June 2007 Analysis Tools Conunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-90.tsf LogPearson III Coefficients Time Series File:c-90.tsf Project Location.:Sea-Tac Mean--0.989 StdDev-0.096 Skew-0.559 Frequencies & Peaks saved to File:c-90.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-90.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-90.dur Analysis Tools Cormnand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Project Location : Production of Runoff Time Series Sea-Tac Computing Series Regional Scale Factor ; c-100.tsf 1. 00 Data Type: Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf 0.45 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.33 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STTG60H.rnf 0.61 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 0.17 acres Total Area 1.56 acres Peak Discharge: 0.250 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-100.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-100.tsf LogPearson III Coefficients B-13 SE 144'1' Strw-June2007 Time Series File:c-100.tsf Project Location:Sea-Tac Mean--1.001 StdDev-0.167 Skew-0.401 Frequencies & Peaks saved to File:c-100.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-100.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-100.dur Analysis Tools Corrunand FETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-106.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Outwash Pasture Outwash Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf 2.50 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.12 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTG60H.rnf 3.34 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STOP60H.rnf 0.12 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf 3.34 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 4.64 acres Total Area 14.06 acres Peak Discharge: 3.02 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-106.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-106.tsf Loading Stage/Discharge curve:c-106.tsf LogPearson III Coefficients Mean= 0.164 StdDev-0.122 B-14 SE 1 ,t,f' Street-June 2007 Project Location:Sea-Tac Skew-0. 511 Frequencies & Peaks saved to File:c-106.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-106.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-106.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-110.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STTF60H.rnf Till Forest 6.43 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTP60H.rnf Till Pasture 12.24 acres Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 12.33 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 7.10 acres Total Area 38.10 acres Peak Discharge: 6.91 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-110.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-110.tsf LogPearson III Coefficients Time Series File:c-110.tsf Project Location:Sea-Tac Mean= 0.487 StdDev-0.145 Skew-0. 484 SE I 4,f' Street-June 2007 Frequencies & Peaks saved to File:c-110.pks Analysis Tools Conunand Compute Flow DURATION and Exceedence B-15 Loading Time Series File:c-110.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-110.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-120.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Pasture Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.58 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.00 acres Total Area 1.58 acres Peak Discharge: 0.466 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-120.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-120.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-120.tsf Project Location:Sea-Tac Mean--0.565 StdDev-0.101 Skew-0.475 Frequencies & Peaks saved to File:c-120.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-120.tsf Durations & Exceedence Probabilities to File:c-120.dur SE 14.f' Street-June 2007 Analysis Tools Command RETURN to Previous Menu B-16 KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-130.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 2.49 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 7.12 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 5.80 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.58 acres Total Area 16.99 acres Peak Discharge: 2.64 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-130.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-130.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-130.tsf Project Location:Sea-Tac Mean= 0.015 StdDev= 0.175 Skew= 0.324 Frequencies & Peaks saved to File:c-130.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-130.tsf Computing Interval Locations Computing Flow Durations SE 144" Street-June 2007 Durations & Exceedence Probabilities to File:c-130.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series B-17 Project Location: Sea-Tac Computing Series c-200.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf -- Till Forest 4.45 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC_DATA\STTP60H.rnf 0.14 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 1.79 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.18 acres Total Area 7.56 acres Peak Discharge: 1.12 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-200.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-200.tsf LogPearson III Coefficients Time Series File:c-200.tsf Project Location:Sea-Tac Mean--0.308 StdDev-0.145 Skew-0. 500 Frequencies & Peaks saved to File:c-200.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-200.tsf Durations & Exceedence Probabilities to File:c-200.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-210.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf B-18 SE 14,f' Street-June 2007 Till Forest Till Pasture Till Grass Impervious 3.31 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTP60H.rnf 1.70 acres Loading Time Series File:C: \KC_SWDM\KC DATA\STTG60H. rnf 4.60 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 2.93 acres Total Area 12.54 acres Peak Discharge: 2.47 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-210.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-210.tsf LogPearson III Coefficients Time Series File:c-210.tsf Project Location:Sea-Tac Mean-0.056 StdDev-0.136 Skew-0.482 Frequencies & Peaks saved to File:c-210.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-210.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-210.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-220.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Grass Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 1.56 acres Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.90 acres Total Area 3.46 acres Peak Discharge: 1.09 CFS at 6:00 on Jan 9 in 1990 B-19 SE 144'1' Streel-June 2007 Storing Time Series File:c-220.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-220.tsf LogPearson III Coefficients Time Series File:c-220.tsf Project Location:Sea-Tac Mean= -0.235 StdDev= 0.114 Skew= 0.400 Frequencies & Peaks saved to File:c-220.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-220.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-220.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-230.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf Till Pasture 3.95 acres Impervious Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf 5.71 acres Total Area 9.66 acres Peak Discharge: 2.72 CFS at 6: 00 on Jan 9 in 1990 SE 144°' Street -June 2007 Storing Time Series File:c-230.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand B-20 Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-230.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-230.tsf Project Location:Sea-Tac Mean= 0.197 StdDev~ 0.103 Skew~ 0.461 Frequencies & Peaks saved to File:c-230.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-230.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-230.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location ; Sea-Tac Computing Series c-232.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 1. 38 acres Total Area 1.38 acres Peak Discharge: 0.093 CFS at 9:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-232.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-232.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-232.tsf Project Location:Sea-Tac Mean= -1.477 StdDev= 0.232 Skew= -0.124 SE 14¢~ Street-June 2007 Frequencies & Peaks saved to File:c-232.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence B-21 Loading Time Series File:c-232.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-232.dur Analysis Tools Command RETURN to Previous Menu KCRTS Conunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-240.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf Till Grass 3.65 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 4.48 acres Total Area 8.13 acres Peak Discharge: 2.56 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-240.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-240.tsf LogPearson III Coefficients Time Series File:c-240.tsf Project Location:Sea-Tac Mean-0.137 StdDev-0.114 Skew-0. 402 Frequencies & Peaks saved to File:c-240.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-240.tsf Computing Interval Locations Computing Flow Durations SE 14.f' Street-June 2007 Durations & Exceedence Probabilities to File:c-240.dur Analysis Tools Command RETURN to Previous Menu B-22 KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-241.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STTF60H.rnf Till Forest 0.23 acres Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 2.99 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3. 68 acres Total Area 6.90 acres Peak Discharge: 2.12 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-241.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Conunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-241.tsf LogPearson III Coefficients Time Series File:c-241.tsf Project Location:Sea-Tac Mean= 0.052 StdDev-0.114 Skew-0.403 Frequencies & Peaks saved to File:c-241.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-241.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-241.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : c-244.tsf B-23 SE 14,t, Street-June 2007 Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 0.71 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 11.46 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 10.75 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 4.68 acres Total Area 27.60 acres Peak Discharge: 5.19 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-244.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Cormnand Compute .PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-244.tsf LogPearson III Coefficients Time Series File:c-244.tsf Project Location:Sea-Tac Mean= 0.350 StdDev~ 0.151 Skew~ 0.463 Frequencies & Peaks saved to File:c-244.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-244.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-244.dur Project Location: Computing Series Regional Scale Factor: Analysis Tools Conunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Sea-Tac c-250.tsf 1. 00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf Till Pasture 0.17 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf B-24 SE 14.fh Street-June 2007 Till Grass Impervious 4.66 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3.23 acres Total Area 8.06 acres Peak Discharge: 2.27 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-250.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-250.tsf LogPearson III Coefficients Time Series File:c-250.tsf Project Location:Sea-Tac Mean= 0.048 StdDev-0.126 Skew-0.396 Frequencies & Peaks saved to File:c-250.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-250.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-250.dur Project Location : Computing Series Regional Scale Factor: Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production Sea-Tac c-260.tsf 1. 00 of Runoff Time Series Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf --Till Grass 2. 33 acres Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.74 acres Total Area 4.07 acres Peak Discharge: 1.18 CFS at 6:00 on Jan 9 in 1990 SE 14¢l' Street-June 2007 Storing Time Series File:c-260.tsf Time Series Computed KCRTS Command B-25 Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-260.tsf LogPearson III Coefficients Time Series File:c-260.tsf Project Location:Sea-Tac Mean= -0.230 StdDev= 0.124 Skew= 0.395 Frequencies & Peaks saved to File:c-260.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence ·Loading Time Series File:c-260.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-260.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location: Sea-Tac Computing Series c-270.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC swqMIKC_DATA\STTG60H.rnf Till Grass 2.22 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.60 acres Total Area 3.82 acres Peak Discharge: 1.10 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-270.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-270.tsf LogPearson III Coefficients B-26 SE J 4,th Street-June 2007 Time Series File:c-270.tsf Project Location:Sea-Tac Mean~ -0.263 StdDev-0.125 Skew-0.392 Frequencies & Peaks saved to File:c-2·10.pks Analysis Tools Command Compute Flow DU:RATION and Exceedence Loading Time Series File:c-270.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-270.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-300.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File·· Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 9.47 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 1.73 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 4 .13 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STEI60H.rnf 1.56 acres Total Area 16.89 acres Peak Discharge: 2.19 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-300.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-300.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-300.tsf Project Location:Sea-Tac Mean--0.057 StdDev-0.172 Skew-O. 335 Frequencies & Peaks saved to File:c-300.pks Analysis Tools Command B-27 SE 144'* Street-June 2007 Compute Flow DUAATION and Exceedence Loading Time Series File:c-300.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-300.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-304.tsf Regional Scale Factor: 1.00 Data Type ! Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 2.12 acres Till Pasture Till Grass Impervious Loading Time Series Fi,le:C:\KC_SWDM\KC_DATA\STTP60H.rnf 1.36 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 5.73 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3 .. 74 acres Total Area 12.95 acres Peak Discharge: 2.93 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-304.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-304.tsf LogPearson III Coefficients Time Series File:c-304.tsf Project Location:Sea-Tac Mean= 0.141 StdDev= 0.132 Skew= 0. 426 Frequencies & Peaks saved to File:c-304.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations SE 144"' Street-June 2007 Loading Time Series File:c-304.tsf B-28 Durations & Exceedence Probabilities to File:c-304.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-306.tsf Regional Scale Factor : 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 1.25 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.15 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 0.28 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.08 acres Total Area 1.76 acres Peak Discharge: 0.177 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-306.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-306.tsf LogPearson III Coefficients Time Series File:c-306.tsf Project Location:Sea-Tac Mean--1.180 StdDev-0.204 Skew-0.041 Frequencies & Peaks saved to File:c-306.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-306.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-306.dur Analysis Tools Command RETURN to Previous Menu B-29 SE I 44'1' Street~ June 2007 KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-310.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Forest Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf 9.32 acres Total Area 9.32 acres Peak Discharge: 0.627 CFS at 9:00 on Jan 9 in 1990 Storing Time Series File:c-310.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-310.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-310.tsf Project Location:Sea-Tac Mean~ -0.648 StdDev~ 0.233 Skew~ -0.139 Frequencies & Peaks saved to File:c-310.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-310.tsf Durations & Exceedence Probabilities to File:c-310.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-320.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_OATA\STTF60H.rnf B-30 SE 14.f' Street-June 2007 Till Forest Till Pasture Till Grass Impervious 8.92 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.18 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.33 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 0.09 acres Total Area 9.52 acres Peak Discharge: 0.693 CFS at 9:00 on Jan 9 in 1990 Storing Time Series File:c-320.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-320.tsf LogPearson III Coefficients Time Series File:c-320.tsf Project Location:Sea-Tac Mean~ -0.597 StdDev~ 0.226 Skew~ -0.141 Frequencies & Peaks saved to File:c-320.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-320.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-320.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-330.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf Till Forest 1.37 acres Till Pasture Till Grass SE l44'1'Street-Junel007 Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.34 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 0. 62 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf B-31 Impervious 0.17 acres Total Area 2.50 acres Peak Discharge: 0.307 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-330.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-330.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-330.tsf Project Location:Sea-Tac Mean--0.930 StdDev-0.187 Skew-0.198 Frequencies & Peaks saved to File:c-330.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-330.tsf Durations & Exceedence Probabilities to File:c-330.dur SE 14./' Street-June 2007 Analysis Tools Command RETURN to Previous Menu KCRTS Command eXit KCRTS Program B-32 Appendix 8.2 KCRTS Pond Designs Hamilton Place -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice # Height (ft) 1 0.00 2 2. 90 Top Notch Weir: Outflow Rating Curve: Detention Pond 3.00 H:lV 145.91 ft 71.63 ft 10452. sq. ft 19580. sq. ft 0.449 acres 5. 00 ft 505.00 ft 70076. cu. ft 1.609 ac-ft 5.00 ft 12.00 inches 2 Full Head Diameter Discharge (in) (CFS) 1.26 0.096 1. 70 0 .114 None None Evendell Plat -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice # Height (ft) l 0.00 2 5.50 3 5.90 Top Notch Weir: Outflow Rating Curve: Detention Pond 3.00 H:lV 167.00 ft 58.00 ft 9686. sq. ft 23762. sq. ft 0.546 acres 7.50 ft 452.00 ft 115676. cu. ft 2.656 ac-ft 7.50 ft 18.00 inches 3 Full Head Diameter Discharge (in) (CFS) 1.50 0.167 2.30 0.203 2.80 0.269 None None Liberty Grove -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: SE 14.f' Streer-Jun.e 2007 Detention Pond 2.00 H:lV 17 8 .12 ft 89.06 ft B-33 Pipe Diameter (in) 4.0 Pipe Diameter (in) 6.0 6.0 Pond Bottom Area: 15863. sq. ft Top Area at 1 ft. FB: 24128. sq. ft 0.554 acres Effective Storage Depth: 6.00 ft Stage 0 Elevation: 456.00 ft Storage Volume: 115567. cu. ft 2.653 ac-ft Riser Head: 6.00 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Orifice # Height Diameter Discharge (ft) {in) {CFS) 1 0.00 3.31 0.728 2 3.65 4.39 0.001 3 4.81 7.69 1.749 Top Notch Weir: None Outflow Rating Curve: None Nichol's Place -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice#- 1 2 Height (ft) 0.00 3. 90 Top Notch Weir: Length: Weir Height: Outflow Rating Curve: SE 144'1' Street-June 2007 Detention Pond 0.00 H:lV 82.00 ft 71.00 ft 5822. sq. ft 5822. sq. ft 0.134 acres 5. 00 ft 447 .00 ft 29110. cu. ft 0. 668 ac-ft 5. 00 ft 18.00 inches 2 Diameter {in) 0.87 1. 71 Rectangular 1. 00 4.50 None Full Head Discharge {CFS) 0.046 0.083 in ft B-34 Pipe Diameter (in) 8.0 10.0 Pipe Diameter {in) 4.0 Appendix B.3 KCRTS Peak Flow Rates Flow Frequency Analysis LogPearson II I Coefficients Time Series File:c-10.tsf Mean= -1. 641 Sr.dDev= 0.141 Project Location:Sea-Tac Skew= 1.196 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.022 26 2/16/49 21:00 0.070 1 89.50 0.989 0.070 1 3/03/50 16:00 0.046 2 32.13 0.969 0.034 6 2/09/51 2:00 0.044 3 19.58 0.949 0. 018 37 10/15/51 13:00 0.039 4 14.08 0.929 0.017 44 3/24/53 15:00 0.036 5 10.99 0. 909 0.022 27 12/19/53 19: 00 0.034 6 9.01 0.889 0.023 21 2/07/55 17 :00 0.033 7 7.64 0.869 0.025 15 12/20/55 17:00 0.031 8 6.63 0.849 0.022 22 12/09/56 14:00 0.031 9 5.86 0. 829 0.021 28 12/25/57 16:00 0.030 10 5.24 0. 809 0.021 29 1/26/59 20:00 0.028 11 4.75 0. 789 0.025 17 2/06/60 17: 00 0.028 12 4.34 0. 769 0. 02 6 13 2/14/61 21:00 0. 026 13 3.99 0. 74 9 0.018 38 11/22/61 2:00 0.025 14 3.70 0. 729 0 .019 34 12/15/62 2: 00 0. 025 15 3.44 0. 709 0 .022 23 12/31/63 23:00 0.025 16 3.22 0.690 0.018 39 12/21/64 4:00 0.025 17 3.03 0. 670 0.018 40 1/05/66 16:00 0.024 18 2.85 0.650 0. 028 12 1/19/67 14:00 0. 024 19 2.70 0.630 0.030 10 8/24/68 16: 00 0.023 20 2.56 0.610 0.016 46 12/03/68 16:00 0.023 21 2.44 0.590 0.018 41 1/13/70 22:00 0 .022 22 2.32 0. 570 0.018 42 12/05/70 9:00 0. 022 23 2 .22 0. 550 0.044 3 2/27/72 7:00 0.022 24 2.13 0.530 0.017 45 1/13/73 2:00 0.022 25 2.04 0.510 0.018 35 11/28/73 9:00 0.022 26 1. 96 0.490 0 .023 20 12/26/74 23:00 0.022 27 1. 89 0.470 0.016 47 1/14/76 6:00 0.021 28 1.82 0.450 0. 020 30 8/26/77 2:00 0.021 29 1. 75 0.430 0.028 11 9/17/78 2:00 0.020 30 1. 70 0.410 0. 025 14 9/08/79 15:00 0.020 31 1.64 0.390 0.022 25 12/14/79 21:00 0.019 32 1.59 0.370 0.024 18 11/21/80 11:00 0. 019 33 1.54 0.350 0.033 7 10/06/81 0:00 0.019 34 1. 4 9 0.330 0.025 16 10/28/82 16:00 0.018 35 1.45 0.310 0.020 31 3/15/84 20:00 0.018 36 1. 41 0.291 0.017 43 6/06/85 22:00 0.018 37 1.37 0.271 0.022 24 1/18/86 16:00 0.018 38 1. 33 0.251 0.031 9 10/26/86 0:00 0.018 39 1.30 0.231 0.015 49 11/11/87 0:00 0.018 40 1.27 0. 211 0.019 32 8/21/89 17:00 0.018 41 1.24 0.191 0.046 2 1/09/90 8:00 0.018 42 1.21 0.171 0.036 5 11/24/90 8:00 0.017 43 1.18 0.151 0.018 36 1/27/92 15:00 0.017 44 1.15 0.131 0.013 50 11/01/92 16:00 0.017 45 1.12 0.111 0.015 48 11/30/93 22:00 0.016 46 1.10 0.091 0.019 33 11/30/94 4:00 0.016 47 1. 08 0.071 0.039 4 2/08/96 10:00 0.015 48 1. 05 0.051 0. 031 8 1/02/97 6:00 0.015 49 1. 03 0.031 0.024 19 10/04/97 15:00 0.013 50 1. 01 0 .011 B-35 SE I 44"' Street-June 2007 Computed Peaks 0.063 100.00 0.990 Computed Peaks 0.053 50.00 0.980 Computed Peaks 0.045 25.00 0. 9 60 Computed Peaks 0.035 10. 00 0.900 Computed Peaks 0.034 8.00 0.875 Computed Peaks 0.029 5.00 0.800 Computed Peaks 0.021 2.00 0.500 Computed Peaks 0.018 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-20.tsf Mean"" -0.857 StdDev-0.119 Project Location:Sea-Tac Skew-0.941 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.135 24 2/16/49 21:00 0.331 1 89.50 0.989 0.331 1 3/03/50 16:00 0.258 2 32 .13 0. 969 0 .173 10 2/09/51 2:00 0.222 3 19.58 0.949 0.115 37 10/15/51 13:00 0.218 4 14.08 0. 929 0.106 44 3/24/53 15:00 0. 210 5 10.99 0.909 0.132 27 12/19/53 19:00 0 .197 6 9.01 0. 889 0.133 26 2/07/55 17 :00 0.195 7 7.64 0.869 0.139 22 12/20/55 17:00 0.191 8 6.63 0. 84 9 0.143 18 12/09/56 14:00 0.178 9 5.86 0. 82 9 0.132 28 12/25/57 16:00 0.173 10 5.24 0.809 0.116 34 1/26/59 20:00 0 .170 11 4.75 0.789 0.135 23 2/06/60 17:00 0.170 12 4. 34 0. 769 0.140 21 2/14/61 21:00 0.160 13 3.99 0.749 0 .114 38 11/22/61 2:00 0.158 14 3.70 o. 729 0.114 39 12/15/62 2:00 0.155 15 3.44 0.709 0.135 25 12/31/63 23:00 0.150 16 3.22 0.690 0.115 36 12/21/64 4:00 0.149 17 3.03 0.670 0.114 40 1/05/66 16: 00 0.143 18 2.85 0.650 0.170 11 11/13/66 19:00 0.140 19 2.70 0.630 0 .191 8 8/24/68 16:00 0.140 20 2.56 0. 610 0.103 46 12/03/68 16:00 0.140 21 2.44 0.590 0 .113 41 1/13/70 22:00 0.139 22 2.32 0.570 0 .111 42 12/05/70 9:00 0.135 23 2.22 0.550 0.222 3 2/27 /72 7:00 0.135 24 2.13 0.530 0.104 45 1/13/73 2:00 0.135 25 2.04 0.510 0.116 35 11/28/73 9:00 0 .133 26 1. 96 0.490 0.149 17 12/26/74 23:00 0.132 27 1. 89 0.470 0.102 47 11/13/75 19:00 0.132 28 1. 82 0.450 0.129 29 8/26/77 2:00 0 .129 29 1. 75 0. 430 0.178 9 9/17/78 2:00 0.123 30 1. 70 0. 410 0.160 13 9/08/79 15:00 0.122 31 1. 64 0. 390 0.140 19 12/14/79 21:00 0.121 32 1.59 0.370 0.155 15 11/21/80 11:00 0 .117 33 1.54 0.350 0.210 5 10/06/81 0:00 0 .116 34 1. 49 0.330 0.158 14 10/28/82 16:00 0 .116 35 1. 45 0.310 0.123 30 3/15/84 20 :00 0 .115 36 1.41 0. 291 0 .110 43 6/06/85 22:00 0 .115 37 1. 37 0.271 0 .140 20 1/18/86 16:00 0 .114 38 1. 33 0.251 0.197 6 10/26/86 0:00 0 .114 39 1. 30 0.231 0.094 49 11/11/87 0:00 0 .114 40 1.27 0.211 0.122 31 8/21/89 17:00 0 .113 41 1. 24 0 .191 0.258 2 1/09/90 6: 00 0 .111 42 1.21 0.171 0.218 4 11/24/90 8:00 0 .110 43 1.18 0.151 0.117 33 1/27 /92 15:00 0.106 44 1.15 0.131 B-36 SE 14¢1' Street-June 2007 0.086 50 11/01/92 16:00 0.101 45 1.12 0 .111 0.097 48 11/30/93 22:00 0.103 46 1.10 0.091 0.121 32 11/30/94 4:00 0.102 47 1. 08 0.071 0.195 7 2/08/96 10:00 0.097 48 1. 05 0.051 0.170 12 1/02/97 6:00 0.094 49 1. 03 0.031 0.150 16 10/04/97 15:00 0.086 50 1. 01 o. 011 Computed Peaks 0.315 100.00 0. 990 Computed Peaks 0 .277 50.00 0.980 Computed Peaks 0.242 25.00 o. 960 Computed Peaks 0.201 10.00 0.900 Computed Peaks 0.193 8.00 0.875 Computed Peaks 0 .171 5.00 0.800 Computed Peaks 0.133 2.00 0.500 Computed Peaks 0.112 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-30.tsf Mean= -0.949 StdDev-0 .121 Project Location:Sea-Tac Skew-0.973 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.109 25 2/16/49 21 :00 0.276 1 89.50 0.989 0 .276 1 3/03/50 16:00 0.210 2 32 .13 0. 969 0.143 9 2/09/51 2:00 0.183 3 19.58 0. 94 9 0. 092 37 10/15/51 13:00 0.176 4 14.08 0. 929 0.086 44 3/24/53 15:00 0.169 5 10.99 0.909 0.106 27 12/19/53 19:00 0.161 6 9.01 o. 889 0.108 26 2/07/55 17:00 0.158 7 7. 64 0.869 0 .114 20 12/20/55 17: 00 0.154 8 6.63 0.849 0 .116 18 12/09/56 14:00 0.143 9 5.86 0. 829 0.106 28 12/25/57 16:00 0 .143 10 5.24 0.809 0.095 33 1/26/59 20:00 0.139 11 4. 75 0. 78 9 0.110 23 2/06/60 17:00 0 .137 12 4.34 0.769 0 .114 19 2/14/61 21:00 0.129 13 3.99 0.749 0. 092 38 11/22/61 2:00 0.127 14 3.70 0.729 0. 0 92 39 12/15/62 2:00 0.124 15 3. 44 0.709 0.109 24 12/31/63 23:00 0.121 16 3.22 0.690 0.093 36 12/21/64 4:00 0.120 17 3.03 0.670 0. 091 40 1/05/66 16:00 0 .116 18 2.85 0.650 0.137 12 11/13/ 66 19:00 0 .114 19 2.70 0.630 0.154 8 8/24/68 16:00 0 .114 20 2.56 0.610 0.083 46 12/03/68 16:00 0 .113 21 2.44 0.590 0. 0 91 41 1/13/70 22:00 0 .113 22 2.32 0.570 0.089 42 12/05/70 9:00 0 .110 23 2 .22 0.550 0.183 3 2/27 /72 7:00 0.109 24 2.13 0.530 0.084 45 1/13/73 2:00 0.109 25 2.04 0.510 0. 093 35 11/28/73 9:00 0.108 26 1. 96 0.490 0.120 17 12/26/74 23:00 0.106 27 1. 8 9 0.470 0. 082 47 11/13/75 19:00 0.106 28 1. 82 0.450 0.104 29 8/26/77 2:00 0.104 29 1. 75 0.430 0.143 10 9/17/78 2:00 0.099 30 1. 70 0.410 0 .129 13 9/08/79 15:00 0.098 31 1. 64 0.390 0 .113 21 12/14/79 21:00 0.097 32 1. 59 0.370 0.124 15 11/21/80 11: 00 0.095 33 1. 54 0.350 0. 169 5 10/06/81 0:00 0.094 34 1. 49 0.330 0.127 14 10/28/82 16:00 0.093 35 1.45 0.310 0.099 30 3/15/84 20:00 0.093 36 1. 41 0.291 0.088 43 6/06/85 22:00 0.092 37 1. 37 0. 271 0.113 22 1/18/86 16:00 0.092 38 1. 33 0.251 9.37 SE U4"' Street-June 2007 0.158 7 10/26/86 0:00 0. 092 39 1. 30 0.231 0. 076 49 11/11/87 0:00 0. 0 91 40 1. 27 0. 211 0.098 31 8/21/89 17: 00 0.091 41 1. 24 0.191 0.210 2 1/09/90 6:00 0.089 42 1.21 0.171 0 .17 6 4 11/24/90 8:00 0.088 43 1.18 0.151 0.094 34 1/27/92 15:00 0.086 44 1.15 0 .131 0.069 50 11 /01/ 92 16:00 0.084 45 1.12 0 .111 0.078 48 11/30/93 22:00 0.083 46 1.10 0.091 0.097 32 11/30/94 4:00 0.082 47 1.08 0.071 0 .161 6 2/08/96 10:00 0.078 48 1. 05 0.051 0 .139 11 1/02/97 6:00 0.076 49 1. 03 0.031 0.121 16 10/04/97 15:00 0. 0 69 50 1. 01 0. 011 Computed Peaks 0. 259 100.00 0.990 Computed Peaks 0.227 50.00 0.980 Computed Peaks 0. 198 25.00 0. 960 Computed Peaks 0 .163 10.00 0.900 Computed Peaks 0.157 8.00 0.875 Computed Peaks 0 .139 5.00 0.800 Computed Peaks 0 .107 2.00 0.500 Computed Peaks 0.090 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-40.tsf Mean"" -1.104 StdDev-0.105 Project Location:Sea-Tac Skew-0.664 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.078 21 2/16/49 21:00 0.145 1 89.50 0.989 0 .145 1 3/03/50 16:00 0 .135 2 32 .13 0. 969 0.085 17 2/09/51 2:00 0.124 3 19. 58 0. 949 0.068 35 10/15/51 13:00 0.121 4 14.08 0.929 0.062 43 3/24/53 15:00 0.116 5 10.99 0.909 0.074 27 12/19/53 19:00 0.112 6 9.01 0.889 0. 077 23 11/25/54 2:00 0.107 7 7.64 0. 869 0.075 26 11/18/55 15:00 0.105 8 6.63 0.849 0.084 18 12/09/56 14: OD 0.100 9 5.86 0.829 0.077 22 12/25/57 16:00 0.094 10 5.24 0.809 0.061 44 1/26/59 20:00 0.094 11 4.75 0.789 0 .072 28 11/20/59 5:00 0.093 12 4. 34 0.769 0 .072 29 2/14/61 21:00 0.091 13 3.99 0.749 0.067 37 11/22/61 2:00 0. 08 9 14 3.70 0.729 0.065 40 12/15/62 2:00 0.088 15 3. 44 0.709 0. 076 24 12/31/63 23:00 0.088 16 3.22 0.690 0.067 36 12/21/64 4:00 0.085 17 3.03 0.670 0.066 39 1/05/66 16:00 0.084 18 2.85 0.650 0.100 9 11/13/66 19:00 0.083 19 2.70 0.630 0 .112 6 8/24/68 16:00 0.080 20 2.56 0.610 0.060 45 12/03/68 16:00 0.078 21 2.44 0.590 0.067 38 1/13/70 22:00 0.077 22 2.32 0.570 0.065 41 12/05/70 9:00 0.077 23 2.22 0.550 0.107 7 2/27 /72 7:00 0.076 24 2.13 0.530 0.060 46 1/13/73 2:00 0.076 25 2.04 0.510 0.068 34 11/28/73 9:00 0.075 26 1. 96 0.490 0.088 15 12/26/74 23:00 0.074 27 1. 89 0.470 0.060 47 11/13/75 19:00 0.072 28 1. 82 0.450 0.076 25 8/26/77 2:00 0 .072 29 1. 75 0.430 0.105 8 9/17 /78 2:00 0. 072 30 1. 70 0.410 0.094 10 9/08/7 9 15:00 0.071 31 1. 64 0.390 0. 083 19 12/14/79 21:00 0.070 32 1. 59 U.370 B-38 SE 144' Street-June2007 0.091 13 11/21/80 11 :00 0.069 33 1. 54 0. 350 0.124 3 10/06/81 0:00 0.068 34 1.49 0.330 0.093 12 10/28/82 16: 00 0.068 35 1. 45 0.310 0.070 32 1/03/84 1:00 0. 0 67 36 1. 41 0. 291 0.064 42 6/06/85 22:00 0. 0 67 37 1. 37 0.271 0.080 20 1/18/86 16:00 0. 0 67 38 1. 33 0. 251 0 .116 5 10/26/86 0:00 0.066 39 1. 30 0.231 0.055 49 11/11/87 0:00 0. 065 40 1. 27 0 .211 0.072 30 8/21/89 17:00 0. 0 65 41 1. 24 0 .191 0 .135 2 1/09/90 6:00 0. 0 64 42 1.21 0 .171 0 .121 4 11/24/90 8:00 0.062 43 1.18 0.151 0.069 33 1/27/92 15:00 0.061 44 1.15 0 .131 0.050 50 11/01/92 16:00 0.060 45 1.12 0 .111 0.057 48 9/03/94 10:00 0.060 46 1.10 0.091 0.071 31 11/30/94 4:00 0.060 47 1. 08 0.071 0.094 11 2/08/96 10:00 0.057 48 1. 05 0. 051 0.088 16 1/02/97 6:00 0.055 49 1. 03 0.031 0.089 14 10/04/97 15:00 0.050 50 1. 01 0.011 Computed Peaks 0.154 100.00 0.990 Computed Peaks 0.140 50.00 0.980 Computed Peaks 0.126 25.00 0. 960 Computed Peaks 0.108 10.00 0.900 Computed Peaks 0.105 8.00 0.875 Computed Peaks 0.095 5.00 0.800 Computed Peaks 0.077 2.00 0.500 Computed Peaks 0.065 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-42.tsf Mean= -0.747 StdDev-0 .110 Project Location:Sea-Tac Skew= 0.794 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.175 21 2/16/49 21:00 0.372 1 89.50 0. 989 0.372 1 3/03/50 16:00 0. 319 2 32.13 0. 969 0.207 14 2/09/51 2:00 0.277 3 19. 58 0. 94 9 0.151 36 10/15/51 13:00 0 .276 4 14.08 0. 929 0.139 44 3/24/53 15:00 0.263 5 10.99 0.909 0.169 28 12/19/53 19: 00 0.259 6 9.01 0.889 0 .172 25 11/25/54 2:00 0.251 7 7. 64 0.869 0 .172 23 12/20/55 17:00 0.234 8 6.63 0. 849 0.188 18 12/09/56 14:00 0.230 9 5.86 0. 829 0 .172 24 12/25/57 16:00 0.224 10 5.24 0.809 0.144 43 1/26/59 20:00 0 .210 11 4.75 0.789 0 .167 29 2/06/60 17:00 0.209 12 4. 34 0.769 0 .171 26 2/14/61 21:00 0.208 13 3.99 0. 749 0.149 37 11/22/61 2:00 0.207 14 3.70 0. 729 0 .147 40 12/15/62 2: 00· 0.203 15 3.44 0.709 0 .174 22 12/31/63 23:00 0.197 16 3.22 0.690 0.151 35 12/21/64 4:00 0.196 17 3.03 0.670 0.149 38 1/05/66 16:00 0.188 18 2.85 0.650 0.224 10 11/13/66 19:00 0.185 19 2.70 0.630 0.251 7 8/24/68 16:00 0.182 20 2.56 0.610 0 .135 46 12/03/68 16:00 0.175 21 2.44 0.590 0.148 39 1/13/70 22:00 0.174 22 2.32 0.570 0 .146 41 12/05/70 9:00 0.172 23 2.22 0.550 0.263 5 2/27 /72 7:00 0.172 24 2 .13 0.530 0 .136 45 1/13/73 2:00 0.172 25 2. 04 0.510 0.153 34 11/28/73 9:00 0.171 26 1. 96 0.490 B-39 SE 144'h Srreef-June 2007 0.196 17 12/26/74 7.3: 00 0 .170 27 1. 89 0.470 0.134 47 11/13/75 19:00 0 .169 28 1.82 0.450 0.170 27 8/26/77 2:00 0.167 29 1.75 0.430 0.234 8 9/17/78 2: 00 0.160 30 1.70 0.410 0.210 11 9/08/79 15:00 0.158 31 1. 64 0.390 0.185 19 12/14/79 21:00 0.158 32 1. 59 0.370 0.203 15 11/21/80 11: 00 0.154 33 1. 54 0.350 0.276 4 10/06/81 0:00 0.153 34 1. 49 0.330 0.208 13 10/28/82 16:00 0.151 35 1. 45 0.310 0.158 32 1/03/84 1:00 0.151 36 1. 41 0. 291 0.144 42 6/06/85 22:00 0 .14 9 37 1. 37 0.271 0.182 20 1/18/86 16:00 0.149 38 1. 33 0.251 0.259 6 10/26/86 0:00 0.148 39 1. 30 0.231 0.124 49 11/11/87 0:00 0.147 40 1. 27 0 .211 0.160 30 B/21/89 17 :00 0.146 41 1. 24 0.191 0.319 2 1/09/90 6:00 0.144 42 1. 21 0.171 0 .277 3 11/24/90 8:00 0.144 43 1.18 0.151 0.154 33 1/27/92 15:00 0 .139 44 1.15 0.131 0 .113 50 11/01/92 16:00 0.136 45 1.12 0.111 0.128 48 11/30/93 22:00 0.135 46 1.10 0. 091 0.158 31 11/30/94 4:00 0.134 47 1. 08 0. 071 0.230 9 2/08/96 10:00 0.128 48 1. 05 0.051 0.209 12 1/02/97 6:00 0.124 49 1. 03 0.031 0.197 16 10/04/97 15:00 0 .113 50 1. 01 0. 011 Computed Peaks 0.373 100.00 0.990 Computed Peaks 0.334 50.00 0.980 Computed Peaks 0.297 25.00 0. 960 Computed Peaks 0.251 10.00 0.900 Computed Peaks 0.243 8.00 0.875 Computed Peaks 0.218 5.00 0.800 Computed Peaks 0 .173 2.00 0.500 Computed Peaks 0.147 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-44.tsf Mean= -0. 596 StdDev-0 .096 Project Location:Sea-Tac Skew= 0. 562 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.253 21 2/16/49 21: 00 0.407 1 89.50 0.989 0.368 6 3/03/50 16:00 0.407 2 32.13 0. 969 0.246 25 2/09/51 2:00 0.382 3 19.58 0. 949 0.223 34 10/15/51 13:00 0.382 4 14.08 0.929 0.203 43 3/24/53 15:00 0.370 5 10.99 0.909 0.239 28 12/19/53 19:00 0.368 6 9.01 0.889 0.253 22 11/25/54 2:00 0.345 7 7.64 0.869 0.247 24 11/18/55 15:00 0.330 8 6.63 0. 84 9 0.278 15 12/09/56 14:00 0.310 9 5.86 0. 82 9 0.254 20 12/25/57 16: 00 0.307 10 5.24 0.809 0.194 47 11/03/58 17 :00 0.303 11 4.75 0.789 0.239 27 11/20/59 5:00 0.300 12 4.34 0.769 0.214 40 2/14/61 21:00 0.292 13 3.99 0.749 0.221 36 11/22/61 2:00 0.289 14 3. 70 0. 729 0. 211 42 12/15/62 2:00 0.278 15 3.44 0.709 0.244 26 12/31/63 23:00 0.273 16 3.22 0.690 0.221 35 12/21/64 4:00 0.268 17 3.03 0.670 0. 219 38 1/05/66 16:00 0 .262 18 2.85 0.650 0.330 8 11/13/66 19:00 0.260 19 2.70 0.630 0.370 5 8/24/68 16:00 0.254 20 2.56 0.610 B·40 SE 14,f Street-June 2007 0.198 44 12/03/68 16:00 0.253 21 2. 44 0.590 0. 220 37 1/13/70 22:00 0.253 22 2.32 0.570 0.215 39 12/05/70 9:00 0. 251 23 2.22 0.550 0. 303 11 12/08/71 18:00 0.247 24 2.13 0.530 0 .197 46 1/13/73 2:00 0.246 25 2.04 0.510 0. 226 33 11/28/73 9:00 0.244 26 1. 96 0.490 0.289 14 12/26/74 23:00 0.239 27 1. 89 0. 4 70 0.198 45 11/13/75 19: 00 0.239 28 1. 82 0.450 0.251 23 8/26/77 2:00 0.237 29 1. 75 0.430 0.345 7 9/17 /78 2:00 0.234 30 1. 70 0.410 0 .310 9 9/08/79 15:00 0.231 31 1. 64 0.390 0.273 16 12/14/79 21:00 0.228 32 1. 59 0.370 0.300 12 11/21/80 11: 00 0.226 33 1. 54 0.350 0.407 1 10/06/81 0:00 0. 223 34 1. 49 0.330 0.307 10 10/28/82 16:00 0. 221 35 1. 45 0.310 0.231 31 1/03/84 1:00 0.221 36 1.41 0.291 0 .213 41 6/06/85 22:00 0.220 37 1. 37 0.271 0 .262 18 1/18/86 16:00 0. 219 38 1. 33 0.251 0.382 3 10/26/86 0:00 0.215 39 1. 30 0.231 0.183 49 11/11/87 0:00 0. 214 40 1.27 0.211 0.237 29 8/21/89 17: 00 0.213 41 1.24 0.191 0.407 2 1/09/90 6:00 0. 211 42 1.21 0.171 0.382 4 11/24/90 8:00 0.203 43 1.18 0.151 0.228 32 1/27 /92 15:00 0 .198 44 1.15 0.131 0.166 50 11/01/92 16:00 0 .198 45 1.12 0 .111 0.189 48 11/30/93 22 :00 0 .197 46 1.10 0. 091 0.234 30 11/30/94 4:00 0 .194 47 1. 08 0.071 0.268 17 2/08/96 10:00 0.189 48 1. 05 0.051 0.260 19 1/02/97 6:00 0.183 49 1. 03 0.031 0 .292 13 10/04/97 15:00 0.166 50 1. 01 0. 011 Computed Peaks 0.462 100.00 0.990 Computed Peaks 0.425 50.00 0.980 Computed Peaks 0.388 25.00 0. 960 Computed Peaks 0.340 10.00 0.900 Computed Peaks 0.330 8.00 0.875 Computed Peaks 0.303 5.00 0.800 Computed Peaks 0.249 2.00 0.500 Computed Peaks 0.214 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-50.tsf Mean= -0.884 StdDev= 0.095 Project Location:Sea-Tac Skew= 0.562 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0 .130 21 2/16/49 21:00 0.210 1 8 9. 50 0.989 0. 190 6 3/03/50 16:00 0.209 2 32.13 0. 969 0.127 25 2/09/51 2:00 0.196 3 19.58 0.949 0.115 34 10/15/51 13:00 0.196 4 14.08 0. 929 0.105 43 3/24/53 15:00 0 .191 5 10.99 0.909 0 .123 28 12/19/53 19:00 0 .190 6 9.01 0.889 • 0 .130 22 11/25/54 2:00 0.178 7 7. 64 0.869 0.127 24 11/18/55 15:00 0.170 8 6.63 0.849 0 .143 15 12/09/56 14:00 0.160 9 5. 86 0.829 0 .131 20 12/25/57 16:00 0.158 10 5.24 0.809 0.100 47 11/03/58 17:00 0.156 11 4.75 0.789 0.123 27 11/20/59 5:00 0 .1.54 12 4.34 0.769 0.110 40 2/14/61 21:00 0.150 13 3.99 0.749 0 .114 35 11/22/61 2:00 0 .14 9 14 3.70 0. 729 B-41 SE 14,rl' Street-June 2007 0.109 42 12/15/62 2:00 0.143 15 3.44 0.709 0.126 26 12/31/63 23:00 0.140 16 3.22 0.690 0 .114 36 12/21/64 4:00 0.138 17 3.03 0.670 0 .112 38 1/05/66 16:00 0.135 18 2.85 0.650 0.170 8 11/13/66 19:00 0 .134 19 2.70 0.630 0.191 5 8/24/68 16:00 0.131 20 2.56 0.610 0.102 44 12/03/68 16:00 0.130 21 2.44 0.590 0 .113 37 1/13/70 22:00 0.130 22 2.32 0.570 0 .111 39 12/05/70 9:00 0.129 23 2.22 0.550 0 .156 11 12/08/71 18:00 o .127 24 2.13 0.530 0.101 46 1/13/73 2:00 0.127 25 2.04 0.510 0 .116 33 11/28/73 9:00 0.126 26 1. 96 0.490 0.149 14 12/26/74 23:00 0.123 27 1. 89 0.470 0.102 45 11/13/75 19: 00 0.123 28 1. 82 0.450 0.129 23 8/26/77 2:00 0 .122 29 1. 75 0.430 0.178 7 9/17/78 2:00 0.120 30 1. 70 0.410 0.160 9 9/08/79 15:00 0 .119 31 1. 64 0.390 0.140 16 12/14/79 21:00 0 .117 32 1. 59 0.370 0.154 12 11/21/80 11: 00 o .116 33 1. 54 0.350 0.210 1 10/06/81 0:00 0 .115 34 1.49 0.330 0.158 10 10/28/82 16:00 0 .114 35 1. 45 0.310 0.119 31 1/03/84 1:00 0 .114 36 1. 41 0. 291 0 .110 41 6/06/85 22:00 0 .113 37 1. 37 0 .271 0.135 18 1/18/86 16:00 0 .112 38 1. 33 0.251 0.196 3 10/26/86 0:00 0 .111 39 1. 30 0.231 0.094 49 11/11/87 0:00 0 .110 40 1.27 0 .211 0.122 29 8/21/89 17: 00 0.110 41 1.24 0.191 0.209 2 1/09/90 6:00 0.109 42 1.21 0 .171 0.196 4 11/24/90 8:00 0.105 43 1.18 0.151 0 .117 32 1/27 /92 15:00 0 .102 44 1.15 0 .131 0.086 50 11/01/92 16:00 0 .102 45 1.12 0 .111 0.097 48 11/30/93 22:00 0.101 46 1.10 0. 091 0 .120 30 11/30/94 4:00 0.100 47 1. 08 0. 071 0.138 17 2/08/96 10:00 0. 097 48 1. 05 0.051 0.134 19 1/02/97 6:00 0.094 49 1. 03 0.031 0.150 13 10/04/97 15:00 0.086 50 1. 01 0. 011 Computed Peaks 0.238 100.00 0. 990 Computed Peaks 0 .219 50.00 0. 980 Computed Peaks 0.200 25.00 0. 960 Computed Peaks 0 .175 10.00 0.900 Computed Peaks 0.170 8.00 0.875 Computed Peaks 0 .156 5.00 0.800 Computed Peaks 0.128 2.00 0.500 Computed Peaks 0 .110 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-52.tsf Mean= -0.457 StdDev= 0.118 Project Location:Sea-Tac Skew= 0.538 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.357 21 2/16/49 21:00 0.701 1 89.50 0.989 0.701 1 3/03/50 16: 00 0. 669 2 32.13 0.969 0. 397 15 2/09/51 2:00 0 .592 3 19. 58 0.949 0.278 40 10/15/51 13:00 0.563 4 14.08 O. 929 0.270 45 3/24/53 15:00 0.500 5 10.99 0.909 0.335 26 12/19/53 19:00 0.488 6 9.01 0.889 0.338 24 11/25/54 2:00 0.484 7 7. 64 0.869 0.340 23 12/20/55 17:00 0.452 8 6.63 0.849 B-42 SE 14-1' Street-June 2007 0.394 17 12/09/56 14:00 0.448 9 5. 8 6 0.829 0.345 22 12/25/57 16:00 0.427 10 5.24 0.809 0.267 46 1/26/59 20:00 0.423 11 4.75 0. 7 89 0.333 27 11/20/59 5:00 0.405 12 4.34 0. 7 69 0.317 30 2/14/61 21 :00 0.404 13 3.99 0.749 0.289 38 11/22/61 2:00 0.402 14 3.70 0. 729 0.299 35 12/15/62 2:00 0.397 15 3.44 0.709 0.336 25 12/31/63 23:00 0.396 16 3.22 0. 690 0.295 37 12/21/64 4:00 0.394 17 3.03 0.670 0.298 36 1/05/66 16:00 0.389 18 2.85 0.650 0.452 8 11/13/66 19:00 0.387 19 2.70 0.630 0.488 6 8/24/68 16:00 0.374 20 2.56 0.610 0 .272 42 12/03/ 68 16:00 0.357 21 2.44 0. 590 0.300 34 1/13/70 22:00 0.345 22 2.32 0. 570 0 .286 39 12/06/70 8:00 0.340 23 2.22 0.550 0.500 5 2/27/72 7: 00 0.338 24 2.13 0. 530 0 .265 47 1/13/73 2:00 0.336 25 2.04 0.510 0.320 28 11/28/73 9:00 0.335 26 1. 96 o. 4 90 0.423 11 12/26/74 23:00 0.333 27 1. 89 0.470 0.271 43 12/02/75 20:00 0.320 28 1. 82 0. 4 50 0.312 31 8/26/77 2:00 0.319 29 1. 75 0. 430 0.427 10 9/17/78 2:00 0.317 30 1. 70 o. 410 0.374 20 9/08/79 15:00 0.312 31 1. 64 0. 3 90 0.387 19 12/14/79 21:00 0.310 32 1. 59 0. 370 0.404 13 11/21/80 11: 00 0.307 33 1. 54 0.350 0.563 4 10/06/81 0:00 0.300 34 1. 4 9 0.330 0.396 16 10/28/82 16:00 0.299 35 1.45 0.310 0.319 29 1/03/84 1:00 0.298 36 1. 41 0. 2 91 0.270 44 6/06/85 22: 00 0.295 37 1. 37 0.271 0.389 18 1/18/86 16:00 0.289 38 1.33 0. 2 51 0.484 7 10/26/86 0:00 0.286 39 1. 30 0. 2 31 0.212 49 11/11/87 0:00 0.278 40 1.27 0. 211 0.275 41 8/21/89 17:00 0.275 41 1. 24 0 .191 0.669 2 1/09/90 6:00 0.272 42 1.21 0.171 0.592 3 11/24/90 8:00 0.271 43 1.18 0 .151 0.310 32 1/27/92 15:00 0.270 44 1.15 0.131 0.199 50 11/01/ 92 16:00 0.270 45 1.12 0 .111 0.232 48 11/30/93 22:00 0.267 46 1.10 0. 091 0.307 33 11/30/94 4:00 0.265 47 1. 08 0.071 0.448 9 2/08/96 10:00 0.232 48 1.05 0.051 0.402 14 1/02/97 6:00 0.212 49 1. 03 0.031 0.405 12 10/04/97 15:00 o .199 50 1. 01 0. 011 Computed Peaks 0. 729 100.00 0.990 Computed Peaks 0. 657 50.00 0.980 Computed Peaks 0.588 25.00 0. 960 Computed Peaks 0.501 10.00 0.900 Computed Peaks 0.483 8.00 0.875 Computed Peaks 0.435 5.00 0.800 Computed Peaks 0.341 2.00 0.500 Computed Peaks 0.283 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-54.tsf Mean= -0.367 StdDev-o .117 Project Location:Sea-Tac Skew= 0.588 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0. 437 21 2/16/49 21:00 0. 87 6 1 89. 50 0. 989 0.876 1 3/03/50 16:00 0.818 2 32.13 0. 969 B-43 SE 144°' Street-June 2007 0.493 14 2/09/51 2:00 0.720 3 19.58 0.949 0.345 40 10/15/51 13: OD 0.687 4 14.08 0.929 0.332 44 3/24/53 15:00 0.622 5 10.99 0.909 0. 411 26 12/19/53 19:00 0.600 6 9.01 0. 8 8 9 0.415 24 11/25/54 2:00 0.598 7 7.64 0.869 0.420 23 12/20/55 17:00 0. 556 8 6.63 0. 8 4 9 0.480 17 12/09/56 14:00 0.552 9 5. 86 0. 82 9 0.422 22 12/25/57 16:00 0.530 10 5.24 0.809 0.332 45 1/26/59 20:00 0.513 11 4.75 0. 7 8 9 0.407 27 11/20/59 5:00 0.498 12 4. 34 0. 7 69 0.395 28 2/14/61 21:00 0.494 13 3.99 0. 7 4 9 0.356 38 11/22/61 2:00 0.493 14 3.70 0. 7 2 9 0.366 35 12/15/62 2:00 0. 4 93 15 3.44 0.709 0.415 25 12/31/63 23:00 0.488 16 3 .22 0. 690 0.363 37 12/21/64 4:00 0.480 17 3.03 0.670 0.365 36 1/05/66 16:00 0.473 18 2.85 0.650 0.552 9 11/13/66 19:00 0. 470 19 2.70 0.630 0.600 6 8/24/68 16:00 0. 4 66 20 2.56 0.610 0.333 43 12/03/68 16:00 0.437 21 2. 44 0. 5 90 0.367 34 1/13/70 22:00 0.422 22 2.32 0.570 0.350 39 12/06/70 8:00 0.420 23 2.22 0.550 0.622 5 2/27 /72 7:00 0.415 24 2 .13 0.530 0.327 47 1/13/73 2:00 0.415 25 2.04 0.510 0.389 30 11/28/73 9.: 00 0. 411 26 1. 96 0. 4 90 0.513 11 12/26/74 23:00 0.407 27 1. 89 0. 4 70 0.332 46 12/02/75 20:00 0.395 28 1. 82 0. 450 0.386 31 8/26/77 2:00 0.391 29 1. 75 0. 430 0.530 10 9/17/78 2:00 0.389 30 1. 70 0.410 0.466 20 9/08/79 15:00 0.386 31 1. 64 0. 3 90 0.470 19 12/14/79 21 :00 0.379 32 1. 59 0 .370 0. 4 94 13 11/21/80 11: 00 0.377 33 1. 54 0. 350 0.687 4 10/06/81 0:00 0.367 34 1. 4 9 0.330 0.488 16 10/28/82 16:00 0.366 35 1. 45 0.310 0. 3 91 29 3/15/84 20:00 0.365 36 1. 41 0. 2 91 0.334 42 6/06/85 22:00 0.363 37 1. 37 0. 271 0.473 18 1/18/86 16:00 0.356 38 1. 33 0 .251 0.598 7 10/26/86 0:00 0.350 39 1. 30 0.231 0.266 49 11/11/87 0:00 0.345 40 1. 27 0. 211 0.345 41 8/21/89 17: 00 0.345 41 1. 24 0 .191 0.818 2 1/09/90 6:00 0.334 42 1. 21 0.171 0.720 3 11/24/90 8:00 0.333 43 1.18 0.151 0.379 32 1/27/92 15:00 0.332 44 1.15 0.131 0.248 50 11/01/92 16:00 0.332 45 1.12 0 .111 0.288 48 11/30/93 22:00 0.332 46 1.10 0.091 0.377 33 11/30/94 4:00 0.327 47 1. 08 0.071 0.556 8 2/08/96 10:00 0.288 48 1. 05 0.051 0. 4 98 12 1/02/97 6:00 0.266 49 1. 03 0.031 0.493 15 10/04/97 15:00 0.248 50 1. 01 0. 011 Computed Peaks 0.902 100.00 0.990 Computed Peaks 0. 811 SO.OD 0.980 Computed Peaks 0.724 25.00 0. 960 Computed Peaks 0.615 10.00 0.900 Computed Peaks 0.593 8.00 0.875 Computed Peaks 0.534 5.00 0.800 Computed Peaks 0.419 2.00 0.500 Computed Peaks 0. 349 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-60.tsf Mean= -0. 876 StdDev-0. 096 Project Location:Sea-Tac Skew""' 0.561 B-44 SE 14.t' Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.133 21 2/16/49 21:00 0 .214 1 89.50 0.989 0.193 6 3/03/50 16:00 0.213 2 32.13 0. 969 0 .12 9 25 2/09/51 2:00 0.201 3 19.58 0.949 0 .117 34 10/15/51 13:00 0.200 4 14. 08 0. 929 0.107 43 3/24/53 15:00 0.195 5 10.99 0.909 0.125 27 12/19/53 19:00 0.193 6 9.01 0.889 0.133 22 11/25/54 2:00 0.181 7 7. 64 0.869 0 .130 24 11/18/55 15:00 0.173 8 6.63 0.849 0.146 15 12/09/56 14:00 0.163 9 5.86 0.829 0 .133 20 12/25/57 16: 00 0.162 10 5.24 0.809 0.102 47 11/03/58 17:00 0.159 11 4. 75 0.789 0.125 28 11/20/59 5:00 0.157 12 4.34 0. 7 69 0 .112 40 2/14/61 21 :00 0.153 13 3. 99 0.749 0 .116 35 11/22/61 2:00 0.152 14 3. 70 0. 729 0 .111 42 12/15/62 2:00 0.146 15 3.44 0.709 0.128 26 12/31/63 23:00 0.143 16 3.22 0.690 0 .116 36 12/21/64 4:00 0 .140 17 3.03 0.670 0 .115 38 1/05/66 16:00 0.138 18 2.85 0.650 0.173 8 11/13/66 19:00 0.137 19 2. 70 0.630 0.195 5 8/24/68 16:00 0.133 20 2.56 0.610 0.104 44 12/03/68 16:00 0 .133 21 2.44 0.590 0 .116 37 1/13/70 22:00 0.133 22 2.32 0.570 0 .113 39 12/05/70 9:00 0 .132 23 2 .22 0.550 0.159 11 12/08/71 18:00 0.130 24 2 .13 0.530 0.103 46 1/13/73 2:00 0.129 25 2.04 0.510 0 .118 33 11/28/73 9:00 0.128 26 1. 96 0.490 0.152 14 12/26/74 23:00 0.125 27 1. 89 0.470 0.104 45 11/13/75 19:00 0.125 28 1. 82 0.450 0.132 23 8/26/77 2:00 0.124 29 1. 75 0.430 0.181 7 9/17/78 2:00 0.123 30 1. 70 0.410 0 .163 9 9/08/79 15:00 0.121 31 1. 64 0.390 0.143 16 12/14/79 21:00 0.120 32 1. 59 0.370 0.157 12 11/21/80 11:00 0 .118 33 1. 54 0.350 0.214 1 10/06/81 0:00 0 .117 34 1. 49 0.330 0.162 10 10/28/82 16:00 0.116 35 1. 45 0.310 0.121 31 1/03/84 1:00 0.116 36 1. 41 0. 291 0. 112 41 6/06/85 22:00 0.116 37 1. 37 0.271 0.138 18 1/18/86 16:00 0.115 38 1. 33 0.251 0.201 3 10/26/86 0:00 0.113 39 1.30 0.231 0. 096 49 11/11/87 0:00 0.112 40 1. 27 0. 211 0.124 29 8/21/89 17:00 0.112 41 1.24 0.191 0.213 2 1/09/90 6:00 0.111 42 1. 21 0 .171 0.200 4 11/24/90 8:00 0 .107 43 1.18 0.151 0.120 32 1/27 /92 15:00 0.104 44 1.15 0 .131 0.087 50 11/01/92 16: 00 0.104 45 1.12 0 .111 0.099 48 11/30/93 22:00 0 .103 46 1.10 0.091 0.123 30 11/30/94 4:00 0.102 47 1. 08 0. 071 0.140 17 2/08/96 10:00 0.099 48 1. 05 0.051 0. 137 19 1/02/97 6:00 0 .096 49 1. 03 0.031 0 .153 13 10/04/97 15:00 0.087 50 1. 01 0.011 Computed Peaks 0.243 100.00 0.990 Computed Peaks 0.223 50.00 0.980 Computed Peaks 0.204 25.00 0.960 Computed Peaks 0.178 10.00 0.900 Computed Peaks 0.173 8.00 0.875 Computed Peaks 0.159 5.00 0.800 B-45 SE 144'1' Street -June 200 7 Computed Peaks 0.130 2.00 0.500 Computed Peaks 0 .112 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-70.tsf Mean= -0.327 StdDev-0 .133 Project Location;Sea-Tac Skew= 0.509 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0. 492 20 2/16/49 21: 00 1. 06 1 89.50 0.989 1. 06 1 3/03/50 16:00 0. 988 2 32 .13 0. 969 0.578 11 2/09/51 2: 00 0.861 3 19.58 0.949 0.353 45 1/30/52 8:00 0.781 4 14.08 0.929 0.354 44 3/24/53 15:00 0. 729 5 10.99 0.909 0.454 25 12/19/53 19:00 0.667 6 9.01 0.889 0.470 22 2/07/55 17:00 0.635 7 7.64 0.869 0.485 21 12/20/55 17:00 0.610 8 6.63 0.849 0. 54 9 16 12/09/56 14 :00 0.607 9 5 .86 0.829 0. 4 62 23 12/25/57 16: 00 0.604 10 5.24 0.809 0.361 42 1/26/59 20:00 0.578 11 4. 7 5 0.789 0.461 24 11/20/59 5:00 0. 568 12 4.34 0.769 0.432 30 2/14/61 21:00 0.562 13 3.99 0.749 0. 37 6 39 11/22/61 2:00 0.557 14 3.70 0.729 0. 411 32 12/15/62 2:00 0.551 15 3.44 0.709 0.451 26 12/31/63 23:00 0.549 16 3.22 0.690 0.389 37 12/21/64 4:00 0.540 17 3.03 0. 670 0.402 34 1/05/66 16:00 0.536 18 2.85 0.650 0.610 8 11/13/66 19:00 0.508 19 2.70 0. 630 0.635 7 8/24/68 16:00 0. 4 92 20 2.56 0. 610 0. 371 41 12/03/68 16:00 0.485 21 2.44 0.590 0.405 33 1/13/70 22:00 0.470 22 2.32 0. 570 0.396 36 12/06/70 8:00 0. 4 62 23 2.22 0.550 0. 729 5 2/27 /72 7:00 0. 4 61 24 2 .13 0.530 0.355 43 1/13/73 2:00 0. 454 25 2.04 0.510 0.441 28 11/28/73 9:00 0.451 26 1. 96 0.490 0.604 10 12/26/74 23:00 0.450 27 1. 89 0.470 0.373 40 12/02/75 20:00 0.441 28 1. 82 0.450 0.385 38 8/2 6/77 2:00 0.436 29 1. 75 0.430 0.557 14 9/22/78 19:00 0.432 30 1. 70 0.410 0.450 27 9/08/79 15:00 0.416 31 1. 64 0.390 0.536 18 12/14/79 21:00 0 .411 32 1.59 0.370 0. 54 0 17 11/21/80 11: 00 0. 4 05 33 1. 54 0.350 0.781 4 10/06/81 15:00 0.402 34 1. 4 9 0.330 0.508 19 10/28/82 16:00 0.401 35 1. 4 5 0.310 0.436 29 3/15/84 20:00 0.396 36 1. 41 0.291 0. 34 0 46 6/06/85 22:00 0.389 37 1. 37 0. 271 0.562 13 1/18/86 16:00 0. 385 38 1. 33 0.251 0.607 9 10/26/86 0:00 0.376 39 1.30 0.231 0. 2 67 49 1/14/88 0:00 0.373 40 1.27 0. 211 0.321 47 8/21/89 17:00 0.371 41 1. 24 0 .191 0.988 2 1/09/90 6:00 0.361 42 1.21 0 .171 0. 861 3 11/24/90 8:00 0.355 43 1.18 0 .151 0. 416 31 1/27/92 15:00 0.354 44 1.15 0 .131 0. 24 9 50 12/10/92 6:00 0.353 45 1.12 0 .111 0. 283 48 11/30/93 22:00 0.340 46 1.10 0. 091 0. 401 35 11/30/94 ·4: 00 0. 321 47 1. 08 0.071 0. 667 6 2/08/96 10:00 0.283 48 1. 05 0.051 0.568 12 1/02/97 6:00 0. 2 67 49 1. 03 0.031 0. 551 15 10/04/97 15:00 0. 24 9 50 1. 01 0. 011 B-46 SE I 4,f' Street-June 2007 Computed Peaks 1. 08 100.00 0.990 Computed Peaks 0.958 50.00 0.980 Computed Peaks 0.847 25.00 0.960 Computed Peaks 0.707 10.00 0.900 Computed Peaks 0. 680 8.00 0.875 Computed Peaks 0.604 5.00 0.800 Computed Peaks 0.459 2.00 0.500 Computed Peaks o. 371 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-80.tsf Mean= 0.090 StdDev-0.131 Project Location:Sea-Tac Skew= 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.34 18 2/16/49 21:00 2.61 1 89. 50 0.989 2.57 2 3/03/50 16:00 2. 57 2 32 .13 0.969 1. 51 11 2/09/51 2:00 2.31 3 19.58 0.949 0.958 41 1/30/52 8:00 2.05 4 14.08 o. 929 o. 92 6 44 3/24/53 15:00 1. 84 5 10.99 0.909 1.19 25 12/19/53 19:00 1. 77 6 9.01 0. 889 1. 2 8 21 2/07/55 17: 00 1. 65 7 7. 64 o. 869 1. 30 20 12/20/55 17: 00 1. 59 8 6.63 o. 849 1. 48 13 12/09/56 14:00 1. 58 9 5.86 o. 829 1. 2 o 24 12/25/57 16;00 1. 53 10 5.24 0.809 0.915 45 1/26/59 20:00 1.51 11 4.75 o. 7 s 9 1.24 23 11/20/59 5:00 1. 51 12 4.34 0. 769 1. 09 31 2/14/61 21: 00 1. 48 13 3. 99 0. 749 0.938 43 11/22/61 2:00 1. 4 7 14 3.70 0.729 1. 08 32 12/15/62 2:00 1. 41 15 3.44 0.709 1.19 26 12/31/63 23:00 1. 38 16 3.22 0.690 1. 02 37 12/21/64 4:00 1. 36 17 3.03 0.670 1. 08 34 1/05/66 16:00 1. 34 18 2.85 0.650 1. 51 12 11/13/66 19:00 1. 34 19 2.70 0.630 1.59 8 8/24/68 16:00 1. 30 20 2.56 0.610 1. 01 39 12/03/68 16:00 1.28 21 2.44 0.590 1. 08 33 1/13/70 22:00 1. 27 22 2.32 0. 570 1. 05 35 12/06/70 8:00 1. 24 23 2.22 0.550 1. 84 5 2/27 /72 7:00 1.20 24 2.13 0.530 0.954 42 1/13/73 2:00 1.19 25 2.04 o. 510 1.14 28 11/28/73 9:00 1.19 26 1.96 0.490 1. 65 7 12/26/74 23:00 1.15 27 1. 89 0.470 1. 02 36 12/02/75 20:00 1. 14 28 1. 82 0.450 0.972 40 8/26/77 2:00 1.14 29 1. 75 0.430 1. 38 16 9/22/78 19:00 1.10 30 1. 70 0.410 1. 14 29 9/08/79 15:00 1. 09 31 1. 64 0.390 1. 41 15 12/14/79 21:00 1. 08 32 1. 59 0.370 1. 34 19 11/21/80 11: 00 1. 08 33 1. 54 0.350 2.05 4 10/06/81 15:00 1. 08 34 1. 49 0.330 1. 27 22 10/28/82 16:00 1. 05 35 1. 45 0.310 1.15 27 1/03/84 1:00 1. 02 36 1. 41 0.291 0.858 46 6/06/85 22:00 1. 02 37 1. 37 0.271 1. 58 9 1/18/86 16:00 1. 02 38 1. 33 0.251 1.53 10 10/26/86 0:00 1. 01 39 1. 30 0.231 0.707 49 1/14/88 12:00 0. 972 40 1.27 0.211 0.815 47 8/21/89 17:00 0.958 41 1. 24 0.191 2. 61 1 1/09/90 6:00 0.954 42 1.21 0 .171 2.31 3 11/24/90 8:00 0.938 43 1. 18 0.151 1.10 30 1/27/92 15:00 0.926 44 1.15 0.131 B-47 SE 14,f' Street~June 2007 0. 692 50 3/22/93 22:00 0 .. 915 45 1.12 0 .111 0. 717 48 11/30/93 22:00 0.858 46 1.10 0. 0 91 1. 02 38 11/30/94 4:00 0.815 47 1. 08 0.071 1. 77 6 2/08/96 10:00 0.717 48 1. 05 0. 051 1.47 14 1/02/97 6:00 0.707 49 1. 03 0. 031 1.36 17 10/04/97 15:00 0. 692 50 1. 01 0 .Oll Computed Peaks 2.76 100.00 0.990 Computed Peaks 2.47 50.00 0.980 Computed Peaks 2.19 25.00 0. 960 Computed Peaks 1.83 10.00 0.900 Computed Peaks 1. 7 6 8.00 0.875 Computed Peaks 1.57 5.00 0. 800 Computed Peaks 1.20 2.00 0. 500 Computed Peaks 0.973 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-90. tsf Mean= -0.989 StdDev-0. 096 Project Location:Sea-Tac Skew-0.559 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.102 21 2/16/49 21: 00 0.164 1 89.50 0.989 0.148 6 3/03/50 16:00 0.164 2 32.13 0. 969 0.099 25 2/09/51 2: 00 0.155 3 19.58 0.949 0.090 34 10/15/51 13:00 0.155 4 14.08 0. 929 0.082 43 3/24/53 15:00 0.150 5 10.99 0.909 0.096 28 12/19/53 19:00 0.148 6 9.01 0.889 0.102 22 ll/25/54 2:00 0 .139 7 7.64 0. 869 0.100 24 11/18/55 15:00 0 .133 · 8 6. 63 0.849 0.112 15 12/09/56 14:00 0. 125 9 5.86 0. 82 9 0.103 20 12/25/57 16:00 0.124 10 5.24 0.809 0.078 47 ll/03/58 17: 00 0.123 ll 4.75 0.789 0.097 27 ll/20/59 5:00 0.121 12 4. 34 0. 7 69 0.086 40 2/14/61 21:00 0.118 13 3.99 0. 74 9 0.090 35 ll/22/61 2:00 0.117 14 3.70 0. 72 9 0.085 42 12/15/62 2:00 0 .112 15 3.44 0. 709 0.099 26 12/31/63 23:00 0.110 16 3.22 0.690 0.089 36 12/21/64 4:00 0.108 17 3. 03 0.670 0.088 38 1/05/66 16:00 0.106 18 2.85 0.650 0.133 8 ll/13/66 19:00 0.105 19 2.70 0.630 0.150 5 8/24/68 16:00 0.103 20 2.56 0. 610 0.080 44 12/03/68 16:00 0.102 21 2.44 0.590 0.089 37 1/13/70 22:00 0.102 22 2.32 0.570 0.087 39 12/05/70 9:00 0.101 23 2 .22 0.550 0. 123 ll 12/08/71 18:00 0.100 24 2.13 0.530 0.080 46 1/13/73 2:00 0.099 25 2.04 0.510 0.091 33 ll/28/73 9:00 0.099 26 1.96 0.490 0. ll7 14 12/26/74 23:00 0.097 27 1. 89 0.470 0.080 45 11/13/75 19:00 0.096 28 1. 82 0.450 0. 101 23 8/26/77 2:00 0.095 29 1. 75 0.430 0.139 7 9/17/78 2:00 0.095 30 1. 70 0.410 0.125 9 9/08/79 15:00 0.093 31 1. 64 0.390 0.110 16 12/14/79 21:00 0.092 32 1. 59 0.370 0.121 12 ll/21/80 11: 00 0.091 33 1. 54 0.350 0 .164 1 10/06/81 0:00 0.090 34 1. 49 0.330 0. 124 10 10/28/82 16:00 0.090 35 1. 45 0.310 0. 093 31 1/03/84 1:00 0.089 36 1. 41 0. 291 0.086 41 6/06/85 22:00 0.089 37 1. 37 0.271 0.106 18 1/18/86 16:00 0.088 38 1. 33 0.251 B-48 SE 144"' Street-June 2007 0.155 3 10/26/86 0:00 0.087 39 1. 30 0.231 0. 074 49 11/11/87 0:00 0. 08 6 40 1.27 0.211 0.095 29 8/21/89 17:00 0.086 41 1.24 o .191 0.164 2 1/09/90 6:00 0.085 42 1.21 0 .1 71 0.155 4 11/24/90 8:00 0.082 43 1.18 0.151 0 .092 32 1/27/92 15:00 0.080 44 1.15 0.131 0.067 50 11/01/92 16:00 0.080 45 1.12 0 .111 0.076 48 11/30/93 22: 00 0.080 46 1.10 0.091 0.095 30 11/30/94 4:00 0.078 47 1. 08 0.071 0.108 17 2/08/96 10:00 0. 07 6 48 1. 05 0.051 0.105 19 1/02/97 6:00 0.074 49 1. 03 0.031 0 .118 13 10/04/97 15:00 0.067 50 1. 01 o. 011 Computed Peaks 0.187 100.00 0.990 Computed Peaks o .1 n SO.DO 0.980 Computed Peaks 0.157 25.00 0 .960 Computed Peaks 0.137 10.00 0.900 Computed Peaks 0.133 8.00 0.875 Computed Peaks 0.122 5.00 0.800 Computed Peaks 0 .100 2. 00 0.500 Computed Peaks 0.086 1. 30 0. 2 31 Flow Frequency Analysis LogPearson I I I Coefficients Time Series File:c-100.tsf Mean= -1.001 StdDev-0.167 Project Location:Sea-Tac Skew-0.401 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0 .113 18 2/16/49 21:00 0.250 1 89.50 0.989 0.250 1 3/03/50 16:00 0.249 2 32.13 0. 969 0.138 9 2/09/51 2:00 0.216 3 19.58 0. 94 9 0.078 38 1/30/52 8:00 0.188 4 14.08 0. 929 0.069 42 3/24/53 15:00 0 .169 5 10.99 0.909 0.096 23 12/19/53 19:00 0 .169 6 9.01 0.889 0.113 19 2/07/55 17:00 0.149 7 7. 64 0.869 0 .117 16 12/20/55 17 :00 0.147 8 6.63 0.849 0.127 13 12/09/56 14:00 0.138 9 5.86 o. 829 0.094 25 12/25/57 16:00 0.132 10 5.24 0.809 0. 073 41 1/26/59 20:00 0.129 11 4.75 0.789 0.121 14 11/20/59 21:00 0 .129 12 4.34 0. 7 69 0.088 31 2/14/61 21:00 0.127 13 3.99 0.749 0.068 43 11/22/61 2:00 0.121 14 3.70 0. 729 0.091 28 12/15/62 2:00 0.120 15 3.44 0.709 0.094 26 12/31/63 23:00 0.117 16 3.22 0.690 0.077 39 12/21/64 4:00 0.115 17 3.03 0.670 0.086 34 1/05/66 16:00 0.113 .18 2.85 0.650 0.129 11 1/19/67 14:00 0 .113 19 2.70 0.630 0.115 17 8/24/68 16:00 0 .111 20 2.56 0.610 0.084 36 12/03/68 16:00 0.105 21 2.44 0.590 0.088 32 1/13/70 22:00 0.105 22 2.32 0.570 0.089 29 12/06/70 8:00 0.096 23 2.22 0.550 0.169 5 2/27/72 7:00 0.096 24 2 .13 0.530 0.075 40 1/13/73 2:00 0.094 25 2.04 0.510 0. 096 24 11/28/73 9:00 0. 094 26 1. 96 0.490 0.149 7 12/26/74 23:00 0.093 27 1. 89 0.470 0.086 35 12/02/75 20:00 0.091 28 1. 82 0.450 0. 060 45 8/26/77 2:00 0.089 29 1. 75 0.430 0.105 21 9/22/78 19:00 0.088 30 1. 70 0.410 0. 0 64 44 9/08/79 15:00 0.088 31 1. 64 0.390 0.120 15 12/14/79 21:00 0.088 32 1. 59 0.370 B-49 SE 144'~ Street-June 2007 0 .105 22 11/21/80 11: 00 0.087 33 1. 54 0.350 0.188 4 10/06/81 15:00 0.086 34 1. 49 0.330 0.088 JC 10/28/82 16:00 0.086 35 1. 45 0.310 0.093 27 1/03/84 1:00 0.084 36 1. 41 0. 2 91 0. 056 48 6/06/85 22:00 0.081 37 1. 37 0 .271 0.147 8 1/18/86 16:00 0.078 38 1. 33 0.251 0.132 10 11/24/86 3:00 0.077 39 1. 30 0.231 0. 059 47 1/14/88 12:00 0.075 40 1. 27 0.211 0.055 49 11/05/88 14:00 0.073 41 1. 24 0.191 0 .24 9 2 1/09/90 6:00 0.069 42 1. 21 0 .171 0 .216 3 11/24 / 90 8:00 0.068 43 1.18 0.151 0. 087 33 1/27/92 15:00 0.064 44 1.15 0 .131 0.060 46 3/22/93 22:00 0.060 45 1.12 0 .111 0.043 50 11/30/93 22:00 0.060 46 1.10 0. 091 0.081 37 12/27/94 1:00 0.059 47 1. 08 0. 071 0.169 6 2/08/96 10:00 0.056 48 1. 05 0.051 0 .129 12 1/02/97 6:00 0.055 49 1. 03 0.031 o .111 20 10/04/97 15:00 0.043 50 1. 01 0.011 Computed Peaks 0. 273 100.00 0.990 Computed Peaks 0.239 50.00 0.980 Computed Peaks 0.206 25.00 o. 960 Computed Peaks 0.166 10.00 0.900 Computed Peaks 0.158 8.00 0.875 Computed Peaks 0.137 5.00 0.800 Computed Peaks o. 097 2.00 0.500 Computed Peaks 0.074 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-106.tsf Mean= 0.164 StclDev-0.122 Project Location:Sea-Tac Skew= 0.511 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 52 20 2/16/49 21:00 3.02 1 89.50 0. 989 3.02 1 3/03/50 16:00 2.88 2 32.13 o. 969 1. 73 12 2/09/51 2:00 2.54 3 19.58 0. 949 1.13 42 10/15/51 13:00 2.29 4 14. 08 0.929 1.12 44 3/24/53 15:00 2.15 5 10.99 0.909 1. 40 27 12/19/53 19:00 1. 98 6 9.01 0.889 1. 44 23 2/07/55 17:00 1. 98 7 7. 64 0.869 1. 47 22 12/20/55 17:00 1. 96 8 6. 63 0. 84 9 1. 67 15 12/09/56 14:00 1. 84 9 5.86 0.829 1. 43 24 12/25/57 16:00 1. 80 10 5.24 0.809 1.12 43 1/26/59 20:00 1. 73 11 4.75 0.789 1. 41 25 11/20/59 5:00 1. 73 12 4.34 0.769 1. 33 29 2/14/61 21:00 1. 72 13 3.99 0.749 1.17 39 11/22/61 2:00 1. 70 14 3.70 0. 729 1.25 34 12/15/62 2:00 1. 67 15 3.44 0.709 1.41 26 12/31/63 23:00 1. 65 16 3.22 0.690 1. 22 37 12/21/64 4:00 1. 65 17 3.03 0.670 1. 25 36 1/05/66 16: 00 1. 62 18 2.85 0. 650 1. 84 9 11/13/66 19:00 1. 61 19 2.70 0. 630 1. 98 6 8/24/68 16:00 1.52 20 2.56 0.610 1.15 41 12/03/68 16: 00 1.51 21 2.44 0.590 1. 26 33 1/13/70 22:00 1. 47 22 2.32 0.570 1. 20 38 12/06/70 8:00 1. 44 23 2.22 0.550 2 .15 5 2/27 /72 7:00 1. 43 24 2.13 0.530 1.12 45 1/13/73 2:00 1. 41 25 2.04 0.510 1.33 30 11/28/73 9:00 1. 41 26 1. 96 0.490 B·50 SE 144'h Street-June 2007 1.80 10 12/26/74 23:00 1. 40 27 1. 89 0.470 1.16 40 12/02/75 20:00 1. 34 28 1. 82 0. 450 1.26 32 8/26/77 2: 00 1. 33 29 1. 75 0.430 1. 7 3 11 9/17 /78 2:00 1. 33 30 1. 70 0.410 1.51 21 9/08/79 15:00 1. 29 31 1. 64 0. 390 1. 62 18 12/14/79 21: 00 1. 26 32 1. 59 0.370 1. 65 16 11/21/80 11: 00 1. 26 33 1. 54 0.350 2. 2 9 4 10/06/81 0:00 1.25 34 1. 49 0. 330 1. 61 19 10/28/82 16:00 1. 25 35 1. 45 0.310 1. 34 28 1/03/84 1:00 1. 25 36 1. 41 0. 2 91 1.10 47 6/06/85 22:00 1. 22 37 1. 37 o. 271 1. 7 o 14 1/18/86 16: 00 1. 20 38 1. 33 0 .251 1. 96 8 10/26/86 0:00 1.17 39 1. 30 0. 231 0.857 49 11/11/87 0;00 1.16 40 1.27 0.211 1.11 46 8/21/89 17 :00 1.15 41 1.24 0 .191 2.88 2 1/09/90 6:00 1.13 42 1.21 0.171 2.54 3 11/24/90 8:00 1.12 43 1.18 0 .151 1.29 31 1/27/92 15:00 1.12 44 1.15 0.131 0.804 50 11/01/92 16; 00 1.12 45 1.12 0.111 0.937 48 11/30/93 22:00 1.11 46 1.10 0. 0 91 1.25 35 11/30/94 4:00 1.10 47 1. 08 0.071 1. 98 7 2/08/96 10:00 0.937 48 1. 05 0.051 1. 72 13 1/02/97 6:00 0.857 49 1. 03 0.031 1. 65 17 10/04/97 15:00 0.804 50 1. 01 0. 011 Computed Peaks 3.10 100.00 0.990 Computed Peaks 2.79 50.00 0.980 Computed Peaks 2.49 25.00 0. 960 Computed Peaks 2.11 10.00 0.900 Computed Peaks 2.04 8.00 0.875 Computed Peaks 1. 83 5.00 0.800 Computed Peaks 1. 42 2.00 0.500 Computed Peaks 1.17 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-110.tsf Mean= 0.487 StdDev-o .145 Project Location:Sea-Tac Skew= 0.484 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 3.35 20 2/16/49 21:00 6.91 1 89.50 0. 98 9 6.79 2 3/03/50 16:00 6. 79 2 32.13 o. 969 3.89 9 2/09/51 ·2: 00 6.11 3 19.58 0.949 2.38 40 1/30/52 8:00 5.57 4 14.08 0. 92 9 2.21 44 3/24/53 15:00 4.75 5 10.99 0.909 2. 95 25 12/19/53 19:00 4.66 6 9.01 0.889 3.27 22 2/07/55 17; 00 4.31 7 7.64 0.869 3.34 21 12/20/55 17:00 4.16 B 6.63 0. 84 9 3. 77 13 12/09/56 14:00 3.89 9 5.86 0.829 2.95 24 12/25/57 16:00 3.86 10 5.24 0.809 2.22 43 1/26/59 20:00 3.82 11 4.75 0.789 3.38 19 11/20/59 21;00 3.80 12 4.34 0.769 2. 65 34 2/14/61 21:00 3.77 13 3.99 0. 74 9 2 .27 42 11/22/61 2:00 3.74 14 3.70 0. 729 2.73 29 12/15/62 2:00 3.61 15 3.44 0.709 2. 91 26 12/31/63 23:00 3.49 16 3.22 0.690 2. 47 37 12/21/64 4; 00 3.47 17 3.03 0.670 2.66 33 1/05/66 16:00 3.41 18 2.85 0.650 3.86 10 11/13/66 19:00 3.38 19 2.70 0.630 3.80 12 8/24/68 16:00 3.35 20 2.56 0.610 B-51 SE 144'1' Street-June 2007 2.54 36 12/03/68 16:00 3.34 21 2.44 0. 590 2.70 32 1/13/70 22:00 3.27 22 2.32 0.570 2.70 31 12/06/70 8:00 3.02 23 2. 22 0.550 4.75 5 2/27 /72 7:00 2.95 24 2.13 0.530 2.34 41 1/13/73 2:00 2.95 25 2.04 0.510 2.88 27 11/28/73 9:00 2.91 26 1. 96 0. 4 90 4.31 7 12/26/74 23:00 2.88 27 1. 89 0.470 2.58 35 12/02/75 20:00 2.85 28 1. 82 0. 450 2.19 45 8/26/77 2:00 2.73 29 1. 75 0.430 3.47 17 9/22/78 19:00 2.71 30 1. 70 0.410 2.46 39 9/08/79 15:00 2.70 31 l. 64 0.390 3.61 15 12/14/79 21 :00 2.70 32 1. 59 0.370 3.41 18 11/21/80 11 :00 2.66 33 1. 54 0.350 5.57 4 10/06/81 15:00 2.65 34 1. 4 9 0.330 3.02 23 10/28/82 16:00 2.58 35 1. 45 0.310 2. 85 28 1/03/84 1:00 2.54 36 1. 41 0.291 1. 97 46 6/06/85 22:00 2.47 37 1. 37 0.271 4.16 8 1/18/86 16:00 2.47 38 1. 33 0.251 3.82 11 11/24/86 3:00 2. 4 6 39 1. 30 0.231 1. 79 48 1/14/88 12:00 2.38 40 1.27 0 .211 1. 87 47 11/05/88 14:00 2.34 41 1. 24 0 .191 6. 91 1 1/09/90 6:00 2.27 42 1. 21 0.171 6.11 3 11/24/90 8:00 2.22 43 1.18 0 .151 2. 71 30 1/27/92 15:00 2. 21 44 1.15 0.131 1. 77 49 3/22/93 22:00 2 .19 45 1.12 0.111 1. 58 50 11/30/93 22:00 1. 97 46 1. 10 0.091 2.47 38 11/30/94 4:00 1. 87 47 1. 08 0. 071 4.66 6 2/08/96 10:00 1. 79 48 1.05 0.051 3. 74 14 1/02/97 6:00 1. 77 49 1. 03 0.031 3.49 16 10/04/97 15:00 1. 58 50 1. 01 0.011 Computed Peaks 7.46 100.00 0. 990 Computed Peaks 6.60 50.00 0.980 Computed Peaks 5.78 25.00 0. 960 Computed Peaks 4.76 10.00 0.900 Computed Peaks 4.56 8.00 0.875 Computed Peaks 4.01 5.00 0.800 Computed Peaks 2.99 2.00 0.500 Computed Peaks 2.37 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-120.tsf Mean= -0. 565 StdDev-0.101 Project Location:Sea-Tac Skew= 0.475 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.277 21 2/16/49 21:00 0. 4 67 1 89.50 0.989 0.426 4 3/03/50 16:00 0.443 2 32.13 0.969 0. 2 80 20 2/09/51 2:00 0.434 3 19.58 0. 94 9 0.231 38 10/15/51 13: 00 0.426 4 14.08 0. 929 0 .214 45 3/24/53 15:00 0.391 5 10.99 0.909 0.258 27 12/19/53 19:00 0.386 6 9.01 0.889 0.272 23 11/25/54 2:00 0.355 7 7.64 0.869 0. 262 25 11/18/55 15:00 0.351 8 6.63 0.849 0.306 16 12/09/56 14:00 0.336 9 5.86 0. 829 0. 272 22 12/25/57 16:00 0.324 10 5.24 0. 809 0.208 47 11/18/58 13:00 0. 322 11 4.75 0.789 0. 264 24 11/20/59 5:00 0.320 12 4.34 0.769 0.230 39 2/14/61 21:00 0.315 13 3.99 0.749 0.232 37 11/22/61 2:00 0.313 14 3.70 0. 729 B-52 SE J 4.r' Street-June 2007 0.230 40 12/15/62 2:00 0.313 15 3.44 0.709 0.262 26 12/31/63 23:00 0.306 16 3.22 0.690 0.235 36 12/21/64 4:00 0.300 17 3.03 0.670 0.236 35 1/05/66 16:00 0. 2 98 18 2.85 0.650 0.355 7 11/13/66 19:00 0. 2 90 19 2.70 0.630 0.386 6 8/24/68 16:00 0.280 20 2.56 0.610 0.217 43 12/03/68 16:00 0.277 21 2.44 0.590 0.238 34 1/13/70 22:00 0.272 22 2.32 0.570 0 .227 41 12/05/70 9:00 0. 272 23 2.22 0.550 0.336 9 2/27 /72 7:00 0.264 24 2.13 0.530 0.214 46 1/13/73 2:00 0.262 25 2. 04 0.510 0.243 32 11/28/73 9:00 0.262 26 1. 96 0. 4 90 0.324 10 12/26/74 23:00 0.258 27 1.89 0.470 0.216 44 12/02/75 20:00 0.258 28 1. 82 0.450 0.258 28 8/26/77 2:00 0. 24 9 29 1. 75 0. 4 30 0.351 8 9/17/78 2:00 0.247 30 1. 70 0.410 0.315 13 9/08/79 15:00 0.244 31 1. 64 0. 3 90 0.298 18 12/14/79 21:00 0.243 32 1. 59 0.370 0.322 11 11/21/80 11 :00 0.239 33 1. 54 0.350 0.443 2 10/06/81 0:00 0.238 34 1. 49 0.330 0.320 12 10/28/82 16:00 0.236 35 1. 4 5 0.310 0.249 29 1/03/84 1:00 0.235 36 1. 41 0.291 0.220 42 6/06/85 22:00 0.232 37 1. 37 0 .271 0.300 17 1/18/86 16:00 0.231 38 1. 33 0.251 0. 391 5 10/26/86 0:00 0.230 39 1. 30 0.231 0.185 49 11/11/87 0:00 0.230 40 1.27 0. 211 0.239 33 8/21/89 17:00 0 .227 41 1. 24 0.191 0. 4 67 1 1/09/90 6:00 0.220 42 1. 21 0.171 0.434 3 11/24/90 8:00 0.217 43 1.18 0.151 0.244 31 1/27/92 15:00 0.216 44 1.15 0.131 0.169 50 11/01/92 16:00 0.214 45 1.12 0 .111 0.193 48 11/30/93 22:00 0.214 46 1.10 0.091 0.247 30 11/30/94 4:00 0.208 47 1. OB 0 .071 0.313 15 2/08/96 10:00 0.193 48 1. 05 0.051 0. 290 19 1/02/97 6:00 0.185 49 1. 03 0.031 0.313 14 10/04/97 15:00 0 .169 50 1. 01 0. 011 Computed Peaks 0.508 100.00 0.990 Computed Peaks 0.466 50.00 0.980 Computed Peaks 0.425 25.00 0.960 Computed Peaks 0.371 10.00 0.900 Computed Peaks 0.360 8.00 0.875 Computed Peaks 0. 329 5.00 0.800 Computed Peaks 0.268 2.00 0.500 Computed Peaks 0.227 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-130.tsf Mean=: 0.015 StdDev= 0.175 Project Location:Sea-Tac Skew= 0.324 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.16 19 2/16/49 21:00 2. 64 1 89.50 0.989 2. 64 1 3/03/50 16: 00 2.63 2 32 .13 0. 969 1. 47 9 2/09/51 14:00 2.28 3 19. 58 0.949 0. 811 38 1/30/52 8:00 2.05 4 14.08 0. 929 0. 694 43 3/24/53 15:00 1. 79 5 10.99 0.909 0. 990 23 12/19/53 19:00 1. 77 6 9.01 0.889 1.18 17 2/07/55 17: 00 1. 57 7 7.64 0.869 1.22 16 12/20/55 17: 00 1. 55 8 6.63 0.849 B-53 SE 144'~ Street-June 2007 1.33 13 12/09/56 14: 00 1.47 9 5.86 0.829 0. 967 25 12/25/57 16: 00 1. 41 10 5.24 0.809 0.740 41 1/26/59 20:00 1.35 11 4.75 0.789 1.31 14 11/20/59 21: 00 1. 34 12 4.34 0.769 0.894 34 2/14/61 21:00 1. 33 13 3.99 0.749 0.697 42 11/22/61 2:00 1. 31 14 3.70 0.729 0.940 29 12/15/62 2:00 1.26 15 3.44 0.709 0. 961 26 12/31/63 23:00 1. 22 16 3.22 0.690 0.788 39 12/21/64 4:00 1.18 17 3.03 0.670 0.892 35 1/05/66 16:00 1.17 18 2.85 0.650 1.35 11 1/19/67 14:00 1.16 19 2.70 0.630 1.16 20 8/24/68 16:00 1.16 20 2.56 0.610 0.869 36 12/03/68 16:00 1.11 21 2.44 0 .590 0.908 30 1/13/70 22:00 1.11 22 2.32 0.570 0.943 28 12/06/70 8:00 0.990 23 2.22 0.550 1. 77 6 2/27 /72 7:00 0.984 24 2 .13 0.530 0. 778 40 1/13/73 2:00 0.967 25 2.04 0.510 0.984 24 11/28/73 9:00 0. 961 26 1. 96 0. 4 90 1. 57 7 12/26/74 23:00 0. 961 27 1. 89 0.470 0.897 32 12/02/75 20:00 0.943 28 1. 82 0.450 a. 594 47 8/26/77 2:00 0.940 29 1. 75 0.430 1.11 21 9/22/78 19:00 0.908 30 1. 70 0.410 0.607 46 9/08/79 15:00 0. 902 31 1. 64 0.390 1. 26 15 12/14/79 21: 00 0.897 32 1. 59 0.370 1. 11 22 li/21/80 11: 00 0. 897 33 1.54 0. 350 2.05 4 10/06/81 15:00 0.894 34 1. 49 0.330 0.902 31 1/05/83 8:00 0.892 35 1.45 0.310 0.961 27 1/03/84 1:00 0.869 36 1. 41 0. 291 0 .563 49 6/06/85 23:00 0.847 37 1.37 0. 271 1. 55 8 1/18/86 16:00 0. 811 38 1.33 0. 251 1. 41 10 11/24/86 3:00 0.788 39 1.30 0.231 0. 619 45 1/14/88 12:00 0.778 40 1.27 0 .211 0. 567 48 11/05/88 14: 00 0.740 41 1. 24 0.191 2. 63 2 1/09/90 6:00 0.697 42 1.21 0 .171 2.28 3 11/24/90 8:00 0. 694 43 1.18 0.151 0. 897 33 1/27/92 15:00 0.632 44 1.15 0 .131 0.632 44 3/22/93 22:00 0. 619 45 1.12 0 .111 0.413 50 11/30/93 22:00 0.607 46 1.10 0. 091 0.847 37 12/27/94 1:00 0. 594 47 1.08 0.071 1. 79 5 2/08/96 10:00 0.567 48 1.05 0.051 1. 34 12 1/02/97 6:00 0.563 49 1. 03 0.031 1.17 18 10 / 04 / 97 15:00 0.413 50 1. 01 0. 011 Computed Peaks 2.90 100.00 0. 990 Computed Peaks 2.53 50.00 0. 980 Computed Peaks 2.18 25.00 0. 960 Computed Peaks 1. 7 5 10.00 0.900 Computed Peaks 1. 67 8.00 0.875 Computed Peaks 1.44 5.00 0.800 Computed Peaks 1.01 2.00 0.500 Computed Peaks 0.759 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-200.tsf Mean= -0. 308 StdDev-0.145 Project Location:Sea-Tac Skew= 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.561 18 2/16/49 21:00 1.12 1 89.50 0.989 1. 09 2 3/03/50 16: 00 1.09 2 32.13 0.969 B-54 SE 14,f' S1reet-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 24 19 2/16/49 21:00 2.48 1 89.50 0.989 2. 42 2 3/03/50 16:00 2.42 2 32.13 0.969 1. 4 0 11 2/09/51 2:00 2.20 3 19.58 0.949 0.884 40 1/30/52 8:00 1.97 4 14. 08 0.929 0. 845 44 3/24/53 15:00 1. 72 5 10.99 0.909 1.10 25 12/19/53 19:00 1. 66 6 9.01 0. 88 9 1.19 21 2/07/55 17:00 1. 56 7 7.64 0. 869 1. 21 20 12/20/55 17:00 1. 4 9 8 6.63 0.849 1. 38 12 12/09/56 14:00 1. 46 9 5.86 0. 829 1.11 24 12/25/57 16:00 1. 43 10 5.24 0.809 0.835 45 1/26/59 20: 00 1. 40 11 4.75 0. 789 1.18 22 11/20/59 21:00 1. 38 12 4.34 0. 769 0 .996 33 2/14/61 21:00 1. 37 13 3.99 0.749 0. 867 43 11/22/61 2:00 1.37 14 3.70 0. 729 1.01 30 12/15/62 2:00 1. 33 15 3.44 0. 709 1.09 26 12/31/63 23:00 1.30 16 3. 22 0.690 0.936 39 12/21/64 4:00 1.30 17 3.03 0. 670 0.995 34 1/05/66 16:00 1. 27 18 2.85 0.650 1. 43 10 11/13/66 19: 00 1. 24 19 2. 70 0.630 1. 4 6 9 8/24/68 16: 00 1.21 20 2. 5 6 0.610 0.937 38 12/03/68 16:00 1.19 21 2.44 0. 5 90 1. 00 31 1/13/70 22:00 1.18 22 2.32 0.570 0. 98 9 35 12/06/70 8:00 1.16 23 2.22 0.550 1. 72 5 2/27 /72 7:00 1.11 24 2.13 0.530 0. 87 6 41 1/13/73 2:00 1.10 25 2.04 0.510 1. 08 27 11/28/73 9:00 1. 09 26 1. 96 0. 4 90 1. 56 7 12/26/74 23:00 1. 08 27 1. 89 0.470 0. 94 9 36 12/02/75 20: 00 1.06 28 1. 82 0.450 0.870 42 8/26/77 2:00 1. 02 29 1. 75 0.430 1.30 16 9/22/78 19:00 1.01 30 1. 70 0.410 0. 999 32 9/08/79 15:00 1. 00 31 1. 64 0.390 1. 33 15 12/14/79 21:00 0.999 32 1.59 0.370 1.27 18 11/21/80 11 :00 0.996 33 l. 54 0.350 1. 97 4 10/06/81 15:00 0.995 34 1.49 0.330 1.16 23 10/28/82 16:00 0.989 35 1.45 0.310 1. 06 28 1/03/84 1:00 0. 94 9 36 1. 41 0.291 0.775 46 6/06/85 22:00 0.937 37 1. 37 0.271 1.49 8 1/18/86 16:00 0.937 38 1.33 0.251 1.37 13 10/26/86 0:00 0.936 39 1. 30 0.231 0. 656 48 1/14/88 12:00 0.884 40 1. 27 0.211 0. 712 47 11/05/88 14: 00 0.876 41 1.24 0.191 2.48 1 1/09/90 6: 00 0.870 42 1.21 0 .171 2.20 3 11/24/90 8:00 0.867 43 1.18 0.151 1.02 29 1/27/92 15:00 0.845 44 1.15 0 .131 0. 643 49 3/22/93 22:00 0.835 45 1.12 0 .111 0. 636 50 11/30/93 22:00 0.775 46 1.10 0.091 0.937 37 11/30/94 4:00 0. 712 47 1. 08 0. 071 1. 66 6 2/08/ 96 10:00 0.656 48 1. 05 0.051 1. 37 14 1/02/97 6:00 0.643 49 1.03 0.031 1.30 17 10/04/97 15:00 0.636 50 1. 01 0. 011 Computed Peaks 2. 63 100.00 0.990 Computed Peaks 2.34 50.00 0.980 Computed Peaks 2.07 25.00 0.960 Computed Peaks 1. 72 10.00 0.900 Computed Peaks 1. 66 8.00 0.875 Computed Peaks 1. 47 5.00 0.800 B-56 SE 14¢" Street-June 2007 Computed Peaks 1.11 2.00 0.500 Computed Peaks 0. 893 1. 30 0. 231 Flew Frequency Analysis LogPearson III Coefficients Time Series File:c-220.tsf Mean= -0.235 StdDev-0 .114 Project Location:Sea-Tac Skew= 0.400 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.601 21 2/16/49 21:00 1. 09 1 89.50 0. 989 1. 04 2 3/03/50 16:00 1. 04 2 32.13 0. 969 0.624 19 2/09/51 2:00 0.989 3 19.58 0.949 0. 4 6 6 40 10/15/51 13:00 0.955 4 14.08 0.929 0.453 44 3/24/53 15:00 0.823 5 10.99 0.909 0.557 26 12/19/53 19: 00 0. 811 6 9.01 0. 8 89 0.571 23 11/25/54 2:00 0. 772 7 7. 64 0. 8 69 0.558 25 11/18/55 15:00 0. 765 8 6. 63 0.849 0 .672 14 12/09/56 14 :00 0. 723 9 5.86 0. 829 0.584 22 12/25/57 16:00 0.713 10 5.24 0.809 0.432 47 11/18/58 13:00 0.702 11 4.75 0.789 0.567 24 11/20/59 5:00 0.688 12 4.34 0.769 0.501 36 2/14/61 21:00 0.683 13 3.99 o. 749 0.488 38 11/22/61 2:00 0. 672 14 3.70 o. 729 0.501 35 12/15/62 2:00 0.666 15 3.44 0.709 0.556 27 12/31/63 23:00 0.660 16 3.22 0.690 0. 4 97 37 12/21/64 4:00 0.658 17 3.03 0.670 0.503 34 1/05/66 16:00 0. 641 18 2.85 0.650 0.765 8 11/13/66 19:00 0. 624 19 2.70 0.630 0.823 5 8/24/68 16:00 0.622 20 2.56 0.610 0.460 41 12/03/68 16:00 0.601 21 2.44 0.590 0.508 33 1/13/70 22:00 0.584 22 2.32 0.570 0.487 39 12/06/70 8:00 0.571 23 2.22 0.550 0. 772 7 2/27 /72 7:00 0.567 24 2.13 0.530 0.445 46 1/13/73 2:00 0.558 25 2.04 0.510 0.545 28 11/28/73 9:00 0.557 26 1. 96 0.490 0.723 9 12/26/74 23:00 0.556 27 1. 89 0.470 0.460 42 12/02/75 20:00 0.545 28 1. 82 0.450 0.520 31 8/26/77 2:00 0.540 29 1. 75 0.430 0.713 10 9/17 /78 2:00 0.524 30 1. 70 0. 410 0. 622 20 9/08/79 15:00 0.520 31 1. 64 0.390 0.658 17 12/14/79 21:00 0.518 32 1. 59 0.370 0.683 13 11/21/80 11 :00 0.508 33 1. 54 0.350 0.955 4 10/06/81 0:00 0.503 34 1. 4 9 0.330 0.666 15 10/28/82 16:00 0.501 35 1. 45 0.310 0.540 29 1/03/84 1:00 0.501 36 1. 41 0. 291 0. 453 45 6/06/85 22:00 0.497 37 1.37 0.271 0. 660 16 1/18/86 16:00 0.488 38 1. 33 0.251 0. 811 6 10/26/86 0:00 0.487 39 1. 30 0.231 0.351 49 11/11/87 0:00 0.466 40 1. 27 0. 211 0. 455 43 8/21/89 17: 00 0. 4 60 41 1.24 0 .191 1. 09 1 1/09/90 6:00 0 .460 42 1.21 0 .171 0.989 3 11/24/90 8:00 0.455 43 1.18 0.151 0. 524 30 1/27 /92 15:00 0.453 44 1.15 0 .131 0.330 so 11/01/92 16:00 0.453 45 1.12 0 .111 0.386 48 11/30/93 22:00 0.445 46 1.10 0.091 0.518 32 11/30/94 4:00 0.432 47 1.08 0.071 0. 702 11 2/08/96 10:00 0. 38 6 48 1.05 0.051 0. 641 18 1/02/97 6:00 0.351 49 1. 03 0.031 0. 688 12 10/04/97 15:00 0.330 so 1.01 0. 011 B-57 SE 14,r' Street-June 2007 Computed Peaks 1.16 100.00 0. 990 Computed Peaks 1. 05 50.00 0. 980 Computed Peaks 0.953 25.00 0. 960 Computed Peaks 0.822 10.00 0. 900 Computed Peaks 0. 7 95 8.00 0.875 Computed Peaks 0. 721 5. 00 0.800 Computed Peaks 0. 572 2.00 0.500 Computed Peaks 0. 474 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-220rd.tsf Mean= -0.991 StdDev-0.418 Project Location:Sea-Tac Skew= 0.698 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.039 38 2/22/49 22:00 0.935 5.13 1 89.50 0.989 0 .110 19 3/05/50 6:00 0. 681 5.10 2 32.13 0. 969 0.489 6 2/09/51 15:00 0.575 5.08 3 19.58 0.949 0.035 43 2/04/52 8:00 0.569 5.08 4 14. 08 0.929 0.099 22 1/18/53 21:00 0.523 5.07 5 10.99 0.909 0.064 35 1/07/54 20:00 0.489 5.06 6 9.01 0.889 0. 04 0 36 2/08/55 22:00 0.483 5.06 7 7. 64 0.869 0 .15 9 12 1/06/56 10:00 0.478 5.06 8 6. 63 0.849 0.067 34 2/26/57 4:00 0.389 5.04 9 5.86 0.829 0.100 21 1/17/58 7:00 0.277 5.02 10 5.24 0.809 0.040 37 1/27/59 1:00 0.160 4. 87 11 4.75 0.789 0.478 8 11/20/59 21:00 0.159 4.86 12 4.34 0. 7 69 0.134 16 11/24/60 10:00 0.152 4.82 13 3.99 0.749 0.035 46 12/24/61 6:00 0.141 4. 77 14 3.70 0.729 0.087 27 11/26/62 10:00 0 .138 4.75 15 3.44 0. 709 0.100 20 11/19/63 16:00 0.134 4.73 16 3.22 0. 690 0.138 15 11/30/64 14:00 0.120 4.63 17 3.03 0.670 0.077 33 1/06/66 21:00 0.114 4.58 18 2.85 0.650 0 .114 18 12/13/66 11:00 0 .110 4. 54 19 2.70 0.630 0.082 29 1/20/68 19:00 0.100 4.41 20 2.56 0. 610 0.080 30 12/11/68 6:00 0.100 4.41 21 2. 44 0. 590 0.093 23 1/27 /70 2:00 0.099 4.38 22 2.32 0.570 0.087 28 12/07 /70 5:00 0.093 4.30 23 2.22 0.550 0. 4 83 7 3/06/72 19:00 0.093 4.29 24 2.13 0. 530 0.152 13 12/26/72 5:00 0.092 4.28 25 2.04 0.510 0.090 26 1/16/74 18:00 0.090 4.26 26 1. 96 0. 490 0.039 39 1/14/75 2:00 0.087 4.22 27 1. 89 0.470 0.078 32 12/04/75 2: 00 0.087 4.21 28 1. 82 0.450 0.031 49 8/26/77 8:00 0.082 4.15 29 1. 75 0.430 0.120 17 12/15/77 17:00 0.080 4 .13 30 1. 70 0.410 0.032 48 2/13/79 1:00 0.080 4 .13 31 1. 64 0.390 0. 277 10 12/17/79 17:00 0.078 4 .11 32 1. 59 0.370 0. 0 92 25 12/30/80 16:00 0.077 4.10 33 1. 54 0.350 0.681 2 10/06/81 16:00 0.067 4.02 34 1. 49 0.330 0.080 31 1/06/83 14:00 0.064 4.01 35 1. 45 0.310 0.035 45 12/10/83 21:00 0.040 3.85 36 1. 41 0.291 0.037 41 11/04/84 8:00 0.040 3.78 37 1. 37 0.271 0 .141 14 1/18/86 23:00 0.039 3.71 38 1. 33 0.251 0.569 4 11/24/86 4:00 0.039 3.67 39 1.30 0.231 0.038 40 12/10/87 8:00 0.038 3. 49 40 1.27 0.211 0.035 44 11/05/88 23:00 0.037 3 .16 41 1.24 0 .191 0.935 1 1/09/90 8:00 0.037 3 .13 42 1.21 0 .171 0.523 5 11/24/90 11: 00 0.035 3.01 43 1.18 0.151 0.093 24 1/31/92 6:00 0.035 3.00 44 1.15 0.131 B-58 SE J 44'• Street-June 2007 0.034 47 1/26/93 5:00 0.035 2. 92 45 1.12 0.111 0.030 50 2/17/94 23:00 0.035 2.90 46 1.10 0. 091 0.160 11 12/27/94 6:00 0.034 2.75 47 1. 08 o. 071 0.575 3 2/08/96 11: 00 0.032 2.43 48 1. 05 o. 051 0. 38 9 9 1/02/97 10:00 0.031 2.31 49 1. 03 0.031 0.037 42 1/25/98 0:00 0.030 2.22 50 1. 01 0. 011 Computed Peaks 1. 55 5.20 100.00 0. 990 Computed Peaks 1. 04 5.15 50.00 0.980 Computed Peaks 0.678 5.10 25.00 0.960 Computed Peaks 0.368 5.04 10.00 0.900 Computed Peaks 0.323 5.03 8.00 0.875 Computed Peaks 0.219 5.01 5.00 0.800 Computed Peaks 0.091 4.27 2.00 0.500 Computed Peaks 0.048 3. 96 1. 30 0 .231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-230.tsf Mean= 0.197 StdDev-0.103 Project Location:Sea-Tac Skew= 0.461 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 60 21 2/16/49 21:00 2.72 1 89.50 0.989 2. 4 9 4 3/03/50 16: 00 2. 57 2 32.13 0. 969 1. 64 20 2/09/51 2:00 2.53 3 19.58 0.949 1. 32 40 10/15/51 13:00 2.49 4 14.08 0.929 1. 23 46 3/24/53 15:00 2.24 5 10.99 0.909 1. 4 9 27 12/19/53 19:00 2.22 6 9.01 0.889 1. 57 22 11/25/54 2:00 2.05 7 7. 64 0.869 1. 52 25 11/18/55 15:00 2.00 8 6.63 0. 849 1. 77 16 12/09/56 14:00 1. 96 9 5.86 0. 829 1. 57 23 12/25/57 16: 00 1. 88 10 5.24 0. 809 1. 21 47 11/18/58 13:00 1. 86 11 4.75 0.789 1. 54 24 11/20/59 5:00 1. 84 12 4.34 0. 769 1. 33 38 2/14/61 21:00 1. 83 13 3.99 0.749 1. 33 37 11/22/61 2:00 1.81 14 3.70 0. 729 1. 33 39 12/15/62 2:00 1. 80 15 3.44 0.709 1.52 26 12/31/63 23:00 1.77 16 3.22 0.690 1. 3 6 36 12/21/64 4:00 1. 75 17 3.03 0.670 1. 37 34 1/05/66 16:00 1. 73 18 2.85 0.650 2.05 7 11/13/66 19:00 1. 68 19 2.70 0.630 2.22 6 8/24/68 16:00 1. 64 20 2.56 0.610 1. 26 42 12/03/68 16:00 1. 60 21 2.44 0.590 1. 38 33 1/13/70 22:00 1. 57 22 2.32 0.570 1. 31 41 12/06/70 8:00 1. 57 23 2.22 0.550 1. 96 9 2/27/72 7:00 1. 54 24 2.13 0.530 1. 24 45 1/13/73 2:00 1. 52 25 2.04 0.510 1. 40 32 11/28/73 9:00 1. 52 26 1. 96 0. 4 90 1. 88 10 12/26/74 23:00 1. 49 27 1. 89 0.470 1.25 44 12/02/75 20:00 1. 4 7 28 1. 82 0.450 1. 47 28 8/26/77 2:00 1. 44 29 1. 75 0. 430 2.00 8 9/17/78 2:00 1.42 30 1. 70 0.410 1. 80 15 9/08/79 15:00 1. 41 31 1. 64 0.390 1. 73 18 12/14/79 21:00 1. 40 32 1. 59 0. 370 1. 86 11 11/21/80 11 :00 1. 38 33 1.54 0.350 2.57 2 10/06/81 0:00 1. 37 34 1. 4 9 0.330 1.84 12 10/28/82 16:00 1. 36 35 1. 45 0.310 1. 44 29 1/03/84 1:00 1. 36 36 1. 41 0.291 1.26 43 6/06/85 22:00 1.33 37 1.37 0 .271 1. 75 17 1/18/86 16:00 1. 33 38 1. 33 0.251 B-59 SE J 44'h Street-June 2007 2 .24 5 10/26/86 0:00 1. 33 39 1. 30 0. 231 1.05 19 11/11/87 0:00 1. 32 40 1.27 0 .211 1. 36 35 8/21/89 17:00 1. 31 11 1.24 0 .191 2.72 1 1/09/90 6:00 1. 2 6 42 1.21 0 .171 2. 53 3 11/24/90 8:00 1. 26 43 1.18 0.151 1. 41 31 1/27 /92 15:00 1. 25 44 1.15 0.131 0. 962 50 11/01/92 16:00 1. 24 45 1.12 0 .111 1.10 48 11/30/93 22:00 1. 23 46 1.10 0. 091 1. 42 30 J.1/30/94 4:00 1. 21 47 1. 08 0.071 1. 83 13 2/08/96 10:00 1.10 48 1. 05 0. 051 1. 68 19 1/02/97 6:00 1. 05 49 1. 03 0.031 1.81 14 10/04/97 15:00 0. 962 50 1. 01 0.011 Computed Peaks 2.95 100.00 0.990 Computed Peaks 2.70 50.00 0.980 Computed Peaks 2.46 25. 00 0.960 Computed Peaks 2.15 10.00 0.900 Computed Peaks 2.09 8.00 0.875 Computed Peaks 1. 91 5. 00 0.800 Computed Peaks 1. 55 2.00 0.500 Computed Peaks 1. 31 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-230rd.tsf Mean= -0.774 StdDev= 0.235 Project Location:Sea-Tac Skew= 1.289 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) I ft) Period 0 .118 39 2/22/49 6:00 0.559 7.00 1 89.50 0.989 0.141 17 3/05/50 11:00 0.550 6. 95 2 32 .13 0. 969 0.559 1 2/09/51 20:00 0. 4 84 6.59 3 19.58 0. 94 9 0.108 46 2/04/52 6:00 0.480 6.57 4 14.08 0. 92 9 0.130 29 1/23/53 8:00 0.479 6. 56 5 10.99 0.909 0 .130 30 1/06/54 12:00 0.478 6.56 6 9.01 0.889 0 .129 32 2/08/55 8:00 0.471 6.53 7 7.64 0. 869 0.247 11 1/06/56 12:00 0.452 6.45 8 6.63 0. 849 0 .129 33 2/26/57 4:00 0. 407 6.27 9 5.86 0.829 0 .136 20 1/17/58 8:00 0.291 6.03 10 5.24 0.809 0.119 38 1/24/59 16:00 ·0.247 5. 94 11 4.75 0. 789 0.478 6 11/21/59 3:00 0.219 5. 7 6 12 4.34 0.769 0.142 15 11/24/60 17:00 0.218 5.75 13 3.99 0. 749 0.104 48 12/24/61 6:00 0.176 5.62 14 3.70 0. 729 0 .132 26 11/27 /62 5:00 0 .142 5.42 15 3 .44 0. 709 0 .136 21 11/19/63 18:00 0.142 5.40 16 3.22 0.690 0.218 13 12/01/64 8:00 0.141 5.33 17 3.03 0. 670 0 .125 37 1/07/66 3:00 0.140 5.27 18 2.85 0.650 0.136 22 12/15/66 8:00 0.138 5.16 19 2.70 0.630 0.127 34 1/20/68 21:00 0.136 5.01 20 2.56 0.610 0 .125 35 12/11/68 7:00 0.136 4 .96 21 2.44 0.590 0.132 27 1/27 /70 4:00 0.136 4 .96 22 2.32 0.570 0.134 25 12/07 /70 11: 00 0.135 4. 90 23 2.22 0.550 0.480 4 3/06/72 22:00 0.135 4.89 24 2.13 0.530 0 .219 12 12/27 /72 18:00 0.134 4.83 25 2.04 0.510 0.135 23 1/16/74 19:00 0.132 4.68 26 1.96 0.490 0 .125 36 12/27 /74 10:00 0.132 4.68 27 1. 89 0.470 0.131 28 12/04/75 3:00 0.131 4. 62 28 1. 82 0.450 0.105 47 8/26/77 7:00 0.130 4.54 29 1. 75 0.430 0.138 19 12/15/77 21:00 0.130 4.54 30 1. 70 0.410 0 .102 49 2/12/79 17:00 0.130 4.54 31 1.64 0.390 0. 471 7 12/17/79 20:00 0 .12 9 4.48 32 1.59 0.370 B-60 SE 14,f' Street-June 2007 0.130 31 12/30/80 22:00 0.129 4. 4 6 33 1. 54 0.350 0.291 10 10/06/81 19:00 0 .127 4.31 34 1. 49 0.330 0.135 24 1/08/83 3:00 0.125 4.18 35 1. 4 5 0.310 0 .111 44 12/10/83 19: 00 0.125 4.18 36 1. 41 0.291 0 .117 40 11/04/84 0:00 0.125 4.17 37 1. 37 0.271 0.176 14 1/19/86 7:00 0 .119 3.78 38 1. 33 0 .251 0.407 9 11/24/86 8:00 0 .118 3.72 39 1. 30 0.231 0 .114 41 12/09/87 22:00 0 .117 3.68 40 1. 27 0 .211 0 .113 43 11/05/88 22:00 0 .114 3.53 41 1. 24 0 .191 0.484 3 1/09/90 14:00 0.113 3. 4 6 42 1. 21 0.171 0.452 8 4/05/91 6:00 0 .113 3.40 43 1.18 0.151 0.140 18 1/31/92 22:00 0 .111 3.33 44 1.15 0 .131 0.109 45 3/23/93 12:00 0.109 3.22 45 1.12 0 .111 0.098 50 2/17/94 21:00 0.108 3.15 46 1.10 0. 091 0 .142 16 12/27/94 20:00 0.105 2.98 47 1. 08 0.071 0.550 2 2/09/96 4:00 0.104 2.94 48 1. 05 0.051 0.479 5 1/02/97 12:00 0.102 2. 76 49 1. 03 0.031 0 .113 42 10/30/97 11:00 0.098 2.59 50 1. 01 0.011 Computed Peaks 0.953 7.57 100.00 0.990 Computed Peaks 0. 711 7.51 50.00 0.980 Computed Peaks 0.526 6.81 25.00 0.960 Computed Peaks 0.347 6.09 10.00 0.900 Computed Peaks 0.320 6.07 8.00 0.875 Computed Peaks 0.249 5. 94 5.00 0.800 Computed Peaks 0.150 5.55 2.00 0.500 Computed Peaks 0 .111 3.30 1. 30 0. 231 Flow Frequency Analysis Log Pear son I I I Coefficients Time Series File:c-232.tsf Mean= -1.477 StdDev= 0.232 Project Location:Sea-Tac Skew= -0 .124 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.041 16 2/16/49 22:00 0.093 1 89.50 0.989 0.080 5 3/03/50 16:00 0.088 2 32.13 0. 969 0.088 2 2/09/51 18:00 0.083 3 19.58 0.949 0.028 32 1/30/52 9:00 0.082 4 14.08 0. 929 0.021 42 1/18/53 19:00 0.080 5 10.99 0.909 0.031 27 1/06/54 5:00 0.068 6 9.01 0.889 0.054 10 2/07/55 21:00 0.065 7 7.64 0.869 0.046 13 12/20/55 17:00 0.059 8 6.63 0. 84 9 0.036 21 12/09/56 15:00 0.055 9 5.86 0.829 0.038 20 1/16/58 20:00 0.054 10 5.24 0.809 0.032 24 1/24/59 2:00 0.054 11 4.75 0.789 0.059 8 11/20/59 21:00 0.047 12 4.34 0.769 0. 032 22 2/24/61 15:00 0.046 13 3.99 0. 74 9 0.019 44 1/03/62 1:00 0.045 14 3.70 0. 72 9 0.026 36 11/25/62 14:00 0.042 15 3.44 0.709 0.032 25 1/01/64 18:00 0.041 16 3.22 0.690 0.022 39 11/30/64 12:00 0.040 17 3.03 0.670 0.024 38 1/06/66 3:00 0.040 18 2.85 0.650 0.054 11 1/19/67 14:00 0.039 19 2.70 0.630 0.032 23 2/03/68 23:00 0.038 20 2.56 0.610 0.031 28 12/03/68 17:00 0.036 21 2.44 0.590 0.026 34 1/13/70 23:00 0.032 22 2.32 0.570 0.021 41 12/06/70 8:00 0.032 23 2.22 0.550 0.065 7 2/28/72 3:00 0.032 24 2.13 0.530 0. 029 30 1/13/73 5:00 0.032 25 2.04 0.510 0.031 26 1/15/74 2:00 0.031 26 1. 96 0.490 B-61 SE 144'1' Street-June 2007 0.047 12 12/26/74 23:00 0.031 27 1. 89 0.470 0. 02 9 29 12/03/75 17:00 0.031 28 1.82 0.450 0.004 50 3/24/77 20:00 0.029 29 1. 75 0.430 o. 025 37 12/10/77 17:00 0.029 30 1.70 0.410 0. 015 46 2/12/79 8:00 0. 028 31 1. 64 0.390 0.040 17 12/15/79 8:00 0.028 32 1. 59 0.370 0.022 40 12/26/80 4:00 0.027 33 1. 54 0.350 0.040 18 10/06/81 15:00 0. 026 34 1. 4 9 0.330 0.039 19 1/05/83 8:00 0.026 35 1. 45 0. 310 0.026 35 1/24/84 11: 00 0.026 36 1. 41 0. 291 0.012 48 2/11/85 5:00 0.025 37 1.37 0.271 0.068 6 1/18/86 21:00 0.024 38 1. 33 0.251 0.055 9 11/24/86 4:00 0.022 39 1. 30 0.231 0.021 43 1/14/88 13:00 0.022 40 1.27 0.211 0 .013 47 4/05/89 16:00 0.021 41 1. 24 0.191 0.093 1 1/09/90 9:00 0.021 42 1.21 0 .171 0.082 4 4/05/91 2:00 0.021 43 1.18 0.151 0.027 33 1/27 /92 17: 00 0. 019 44 1.15 0.131 0.028 31 3/23/93 0:00 0.016 45 1.12 0 .111 0.008 49 3/03/94 4: 00 0.015 46 1.10 0.091 0.042 15 2/19/95 20:00 0.013 47 1. 08 0.071 0.083 3 2/09/96 1:00 0.012 48 1. 05 0.051 0.045 14 1/02/97 9:00 0.008 49 1. 03 0.031 0. 016 45 1/07/98 9:00 0.004 50 1. 01 0. 011 Comput.ed Peaks 0 .110 100.00 0.990 Computed Peaks 0.097 50.00 0.980 Computed Peaks 0.083 25.00 0. 960 Computed Peaks 0.066 10.00 0. 900 Computed Peaks 0. 062 8.00 0.875 Computed Peaks 0.053 5.00 0.800 Computed Peaks 0.034 2.00 0.500 Computed Peaks 0.022 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-240.tsf Mean= 0.137 StdDev= 0 .114 Project Location:Sea-Tac Skew= 0.402 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 42 21 2/16/49 21:00 2.57 1 89.50 0.989 2.44 2 3/03/50 16:00 2.44 2 32.13 0.969 1. 47 19 2/09/51 2:00 2.33 3 19.58 0.949 1. io 40 10/15/51 13:00 2.25 4 14.08 0. 929 1. 07 44 3/24/53 15:00 1. 94 5 10.99 0. 909 1. 31 25 12/19/53 19:00 1. 91 6 9.01 0.889 1.34 23 11/25/54 2:00 1. 82 7 7. 64 0.869 1. 31 26 11/18/55 15:00 1. 80 8 6.63 0.849 1. 58 14 12/09/56 14:00 1. 70 9 5.86 0.829 1. 38 22 12/25/57 16:00 1. 68 10 5.24 0.809 1. 02 47 11/18/58 13:00 1. 65 11 4.75 0.789 1. 33 24 11/20/59 5:00 1. 62 12 4.34 0.769 1.18 35 2/14/61 21 :00 1. 61 13 3.99 0.749 1.15 38 11/22/61 2:00 1. 58 14 3.70 0. 729 1.18 36 12/15/62 2:00 1. 57 15 3.44 0.709 1. 31 27 12/31/63 23:00 1. 55 16 3.22 0. 690 1.17 37 12/21/64 4:00 1. 55 17 3.03 0. 670 1.18 34 1/05/66 16:00 1. 51 18 2.85 O. 650 1.80 8 11/13/66 19:00 1.47 19 2.70 0.630 1. 94 5 8/24/68 16:00 1. 46 20 2.56 0. 610 B-62 SE I 4.f' Street-June 2007 1. 08 41 12/03/68 16: 00 1. 42 21 2.44 0.590 1. 20 33 1/13/70 22:00 1. 38 22 2.32 0.570 1.15 39 12/06/70 8:00 1. 34 23 2.22 0.550 1.82 7 2/27 /72 7:00 1. 33 24 2 .13 0.530 1.05 46 1/13/73 2:00 1. 31 25 2.04 0.510 1.28 28 11/28/73 9:00 1. 31 26 1. 96 0. 4 90 1. 70 9 12/26/74 23:00 1. 31 27 1. 89 0.470 1. 08 42 12/02/75 20:00 1. 28 28 1. 82 0.450 1.23 31 8/26/77 2:00 1. 27 29 1. 75 0. 430 1. 68 10 9/17/78 2:00 1. 23 30 1. 70 0.410 1.46 20 9/08/79 15:00 1. 23 31 1.64 0. 390 1. 55 17 12/14/79 21:00 1. 22 32 1. 59 0.370 1. 61 13 11/21/80 11:00 1.20 33 1. 54 0.350 2. 2 5 4 10/06/81 0:00 1.18 34 1. 49 0.330 1.57 15 10/28/82 16:00 1.18 35 1.45 0.310 1.27 29 1/03/84 1:00 1.18 36 1. 41 0.291 1.07 45 6/06/85 22:00 1.17 37 1.37 0.271 1.55 16 1/18/86 16:00 1.15 38 1. 33 0.251 1. 91 6 10/26/86 0:00 1.15 39 1. 30 0.231 0. 82 8 49 11/11/87 0:00 1.10 40 1.27 0 .211 1.07 43 8/21/89 17: 00 1. 08 41 1. 24 0.191 2.57 1 1/09/90 6:00 1.08 42 1.21 0.171 2.33 3 11/24/90 8:00 1. 07 43 1.18 0.151 1. 23 30 1/27/92 15:00 1. 07 44 1.15 0.131 0. 778 50 11/01/92 16:00 1. 07 45 1.12 0 .111 0. 911 48 11/30/93 22:00 1. 05 46 1.10 0.091 1. 22 32 11/30/94 4:00 1.02 47 1.08 0 .071 1. 65 11 2/08/96 10:00 0. 911 48 1. 05 0.051 1. 51 18 1/02/97 6:00 0.828 49 1. 03 0.031 1. 62 12 10/04/97 15:00 0.778 50 1. 01 0.011 Computed Peaks 2. 72 100.00 0.990 Computed Peaks 2. 48 50.00 0.980 Computed Peaks 2.24 25.00 0. 960 Computed Peaks 1. 94 10.00 0.900 Computed Peaks 1. 87 8.00 0.875 Computed Peaks 1. 70 5.00 0.800 Computed Peaks 1.35 2.00 0.500 Computed Peaks 1.12 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-240rd.tsf Mean= -0. 255 StdDev-0.169 Project Location:Sea-Tac Skew-1. 275 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0. 471 30 2/17/49 1:00 1.34 4.97 1 89.50 0. 989 0.524 18 3/04/50 4:00 1. 2 6 4. 89 2 32 .13 0. 969 1. 34 1 2/09/51 19:00 1. 26 4.89 3 19.58 0.949 0.416 44 1/30/52 11: 00 1. 21 4.79 4 14.08 0. 929 0.432 40 9/30/53 17:00 1. 21 4.79 5 10.99 0.909 0.484 25 1/06/54 7:00 1.16 4.63 6 9.01 0.889 0.570 11 2/08/55 0:00 1.15 4. 61 7 7.64 0.869 0.533 16 12/22/55 15:00 1. 08 4.43 8 6.63 0. 84 9 0.512 19 12/09/56 18:00 0.998 4.20 9 5.86 0.829 0.487 24 1/16/58 23:00 0.943 4.08 10 5.24 0.809 0.459 32 10/19/58 9:00 0.570 3.66 11 4.75 0.789 1.15 7 11/20/59 23:00 0.565 3. 61 12 4.34 0.769 0.490 23 11/20/60 16:00 0.553 3.46 13 3.99 0.749 0.382 47 1/03/62 3:00 0.543 3.34 14 3.70 0. 729 B-63 SE 144"' Street-June 2007 0.483 27 11/25/ 62 16:00 0.535 3.24 15 3.44 0.709 0. 473 28 1/01/64 20:00 0.533 3.22 16 3.22 0. 690 0. 4 99 21 11/24/64 10:00 0.528 3. 16 17 3.03 0.670 0.421 43 12/28/65 17: 00 0.524 3 .11 18 2.85 0.650 0.543 14 1/19/67 19:00 0.512 2. 96 19 2.70 0.630 0.442 38 2/19/68 4:00 0.508 2. 92 20 2.56 0.610 0. 4 71 29 12/03/68 22:00 0. 4 99 2.82 21 2.44 0 .590 0. 469 31 1/14/70 14: 00 0. 4 97 2.80 22 2.32 0.570 0.508 20 12/06/70 14:00 0. 4 90 2.73 23 2 .22 0.550 0.998 9 2/28/72 7:00 0.487 2.69 24 2 .13 0.530 0.440 39 12/26/72 6:00 0.484 2. 65 25 2.04 0.510 0. 44 8 36 1/15/74 8:00 0. 4 83 2.65 26 1. 96 0. 4 90 0.553 13 12/27 /7 4 6:00 0.483 2. 64 27 1.89 0.470 0. 4 97 22 12/04/75 1:00 0.473 2.53 28 1. 82 0.450 0.359 49 8/24/77 0:00 0.471 2.51 29 1. 7 5 0.430 0.483 26 9/23/78 11: 00 0.471 2.51 30 1. 70 0.410 0.387 46 11/19/78 8: 00 0.469 2.48 31 1. 64 0.390 0.943 10 12/15/79 9:00 0.459 2.38 32 1.59 0.370 0. 42 6 42 11/21/80 14:00 0. 457 2. 36 33 1.54 0.350 1.26 3 10/06/81 17:00 0. 455 2.34 34 1. 4 9 0.330 0 .528 17 1/05/83 15:00 0. 450 2.30 35 1.45 0.310 0. 40 9 45 1/24/84 13:00 0.448 2.28 36 1.41 0.291 0.455 34 6/07/85 7:00 0.444 2.24 37 1. 37 0. 271 1. 08 8 1/18/86 22: 00 0.442 2.21 38 1.33 0.251 1.16 6 11/24/86 7:00 0.440 2.20 39 1.30 0.231 0.427 41 1/14/88 19: 00 0. 432 2 .11 40 1.27 0.211 0.368 48 11/05/88 19: 00 0 .427 2.06 41 1.24 0 .191 1. 2 6 2 1/09/90 11: 00 0. 42 6 2.05 42 1.21 0.171 1. 21 4 4/05/91 3:00 0.421 2.01 43 1.18 0.151 0.444 37 1/28/92 10:00 0.416 1. 96 44 1.15 0 .131 0.450 35 3/23/93 5:00 0.409 1. 89 45 1.12 0 .111 0.333 50 12/01/93 16:00 0.387 1. 70 46 1.10 0. 0 91 0.535 15 2/19/95 22 :00 0.382 1. 66 47 1.08 0.071 1. 21 5 2/09/96 3: 00 0. 368 1.53 48 1. 05 0.051 0.565 12 1/02/97 12:00 0.359 1. 46 49 1. 03 0. 031 0 .457 33 10/30/97 9:00 0.333 1.26 50 1. 01 o .. 011 Computed Peaks 1. 93 5.23 100.00 0.990 Computed Peaks 1. 56 5.10 50.00 0.980 Computed Peaks 1.26 4.89 25.00 0.960 Computed Peaks 0.935 4.07 10.00 0.900 Computed Peaks 0.881 3.99 8.00 0.875 Computed Peaks 0.736 3.89 5.00 0.800 Computed Peaks 0.512 2.97 2.00 0.500 Computed Peaks 0. 411 1. 91 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-241. tsf Mean= 0.052 StdDev-0 .114 Project Location:Sea-Tac Skew= 0.403 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.17 21 2/16/49 21:00 2.12 1 89.50 0.989 2.02 2 3/03/50 16: 00 2.02 2 32 .13 0.969 1. 21 19 2/09/51 2:00 1. 93 3 19.58 0. 949 0.902 40 10/15/51 13:00 1.85 4 14.08 0. 929 0. 87 9 44 3/24/53 15:00 1. 59 5 10.99 0.909 1. 08 25 12/19/53 19:00 1. 57 6 9.01 0.889 1.11 23 11/25/54 2:00 1. 50 7 7. 64 0.869 1. 08 26 11/18/55 15:00 1. 4 8 8 6. 63 0.849 B-64 SE J 411' Streer -June 2007 1. 30 14 12/09/56 14: 00 1.40 9 5.86 0.829 1.13 22 12/25/57 16:00 1. 38 10 5.24 0.809 0.838 47 11/18/58 13:00 1. 37 11 4.75 0.789 1.10 24 11/20/59 5:00 1.33 12 4. 34 0. 7 69 0.972 36 2/14/61 21 :00 1. 32 13 3.99 0.749 0.943 39 11/22/61 2:00 1.30 14 3.70 0.729 0.973 35 12/15/62 2:00 1. 29 15 3.44 0.709 1. 08 27 12/31/63 23:00 1.29 16 3.22 0. 690 0.964 37 12/21/64 4:00 1.27 17 3.03 0.670 0.976 34 1/05/66 16:00 1. 24 18 2.85 0.650 1.48 8 11/13/66 19:00 1.21 19 2.70 0.630 1. 59 5 8/24/68 16:00 1. 20 20 2.56 0.610 0.893 42 12/03/68 16:00 1.17 21 2.44 0.590 0.985 33 1/13/70 22:00 1.13 22 2.32 0.570 0.945 38 12/06/70 8:00 1.11 23 2.22 0.550 1. 50 7 2/27 /72 7:00 1.10 24 2.13 0.530 0.864 46 1/13/73 2: DO 1. 08 25 2.04 0.510 1. 06 28 11/28/73 9:00 1.08 26 1. 96 0. 490 1. 40 9 12/26/74 23:00 1. 08 27 1. 89 0.470 0.894 41 12/02/75 20:00 1. 06 28 1.82 0.450 1. 01 31 8/26/77 2:00 1. 05 29 1. 75 0.430 1. 38 10 9/17 /78 2:00 1.02 30 1. 70 0.410 1. 20 20 9/08/79 15:00 1. 01 31 1. 64 0.390 1. 27 17 12/14/79 21: 00 1.00 32 1. 59 0.370 1. 32 13 11/21/80 11 :00 0.985 33 1. 54 0.350 1. 85 4 10/06/81 0:00 0.976 34 1. 49 0.330 1. 29 15 10/28/82 16:00 0.973 35 1. 4 5 0.310 1. 05 29 1/03/84 1:00 0.972 36 1. 41 0.291 0.877 45 6/06/85 22:00 0. 964 37 1. 37 0.271 1. 29 16 1/18/86 16:00 0.945 38 1. 33 0.251 1. 57 6 10/26/86 0:00 0.943 39 1. 30 0.231 0.680 49 11/11/87 0:00 0.902 40 1. 27 D. 211 0.881 43 8/21/89 17: 00 0.894 41 1. 24 0. 191 2.12 1 1/09/90 6:00 0.893 42 1.21 0 .171 1. 93 3 11/24/90 8:00 0.881 43 1.18 0.151 1. 02 30 1/27/92 15:00 0.879 44 1.15 0.131 0.639 50 11/01/92 16:00 0.877 45 1.12 0 .111 0.748 48 11/30/93 22: DO 0.864 46 1.10 0.091 1.00 32 11/30/94 4:00 0.838 47 1. 08 D. 071 1. 37 11 2/08/96 10:00 0.748 48 1. 05 0.051 1. 24 18 1/02/97 6:00 0.680 49 1. 03 0.031 1. 33 12 10/04/97 15:00 0.639 50 1. 01 0.011 Computed Peaks 2.25 100.00 0. 990 Computed Peaks 2.05 SO.OD 0.980 Computed Peaks 1. 85 25.00 0.960 Computed Peaks 1. 60 10.00 0.900 Computed Peaks 1. 54 8.00 0.875 Computed Peaks 1. 40 5.00 0.800 Computed Peaks 1.11 2.00 0.500 Computed Peaks 0. 920 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-244.tsf Mean= 0.350 StdDev~ 0.151 Project Location:Sea-Tac Skew= 0. 4 63 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 2.43 21 2/16/49 21:00 5 .19 1 89.50 0. 989 5.15 2 3/03/50 16:00 5.15 2 32.13 0.969 B-65 SE 14,1' Street-June 2007 2.87 10 2/09/51 2:00 4.57 3 19.58 0.949 1. 72 39 1/30/52 8:00 4. 21 4 14.08 0. 929 1. 58 44 3/24/53 15:00 3.54 5 10.99 0.909 2.15 25 12/19/ 53 19: 00 3. 44 6 9.01 0.889 2.38 22 2/07/55 17:00 3.19 7 7.64 0.869 2.45 20 12/20/55 17:00 3.06 8 6.63 0.849 2.78 12 12/09/56 14:00 2.89 9 5.86 0.829 2.16 24 12/25/57 16:00 2.87 10 5.24 0.809 1. 61 43 1/26/59 20:00 2.82 11 4.75 0.789 2. 4 9 19 11/20/59 21:00 2.78 12 4, 34 0.769 1. 93 33 2/14/ 61 21:00 2.76 13 3.99 0.749 1. 65 42 11/22/61 2:00 2.74 14 3. 70 0.729 2.00 29 12 /15/ 62 2:00 2.68 15 3.44 0.709 2.10 27 12/31/63 23:00 2.63 16 3.22 0. 690 1. 78 38 12/21/64 4:00 2. 57 17 3.03 0.670 1. 93 34 1/05/66 16:00 2.53 18 2.85 0.650 2.89 9 11/13/66 19:00 2.49 19 2.70 0.630 2.76 13 8/24/68 16:00 2.45 20 2.56 0.610 1. 83 36 12/03/68 16:00 2.43 21 2.44 0.590 1. 96 32 l / 13/70 22:00 2.38 22 2.32 0.570 2.00 30 12/06/70 8:00 2.18 23 2.22 0.550 3.54 5 2/27 /72 7:00 2.16 24 2.13 0.530 1. 68 40 l/ 13/73 2:00 2 .15 25 2.04 0.510 2.14 26 11/28/73 9:00 2.14 26 1. 96 0.490 3 .19 7 12/26/74 23:00 2.10 27 1. 89 0.470 1. 87 35 12/02/75 20:00 2.08 28 1. 82 0.450 1. 53 45 8/26/77 2:00 2.00 29 1. 75 0.430 2.57 17 9/22/78 19:00 2.00 30 1. 70 0.410 1. 67 41 9/08/79 15:00 1. 97 31 1.64 0.390 2. 68 15 12/14/79 21 :00 1. 96 32 1. 59 0.370 2. 53 18 11/21/80 11:00 1. 93 33 J. 54 0.350 4.21 4 10/06/81 15:00 1. 93 34 1. 49 0.330 2.18 23 10/28/82 16:00 1. 87 35 J. 45 0.310 2.08 28 1/03/84 1:00 1. 83 36 J. 41 0.291 1. 40 46 6/06/85 22:00 1. 79 37 1.37 0 .271 3.06 8 1/18/86 16:00 1. 78 38 1. 33 0.251 2. 82 1i 11/24/86 3:00 1. 72 39 1. 30 0.231 1. 30 48 1/14/88 12:00 1. 68 40 1.27 0. 211 1. 36 47 11/05/88 14:00 1. 67 41 1. 24 0.191 5.19 1 1/09/90 6:00 1. 65 42 1.21 0.171 4.57 3 11/24/90 8:00 1.61 43 1.18 0.151 1. 97 31 1/27/92 15:00 1. 58 44 1.15 0.131 1.28 49 3/22/93 22:00 1. 53 45 1.12 0 .111 1. 09 50 11/30/93 22:00 1. 40 46 1.10 0.091 1. 79 37 11/30/94 4:00 1.36 47 J. 08 0. 071 3.44 6 2/08/96 10:00 1. 30 48 1. 05 0.051 2.74 14 1/02/97 6:00 1.28 49 1. 03 0.031 2. 63 16 10/04/97 15:00 1. 09 50 J. 01 0. 011 Computed Peaks 5.65 100.00 0.990 Computed Peaks 4.97 50.00 0. 980 Computed Peaks 4.33 25.00 0.960 Computed Peaks 3.54 10.00 0. 900 Computed Peaks 3.39 8.00 0.875 Computed Peaks 2. 97 5.00 0.800 Computed Peaks 2.18 2.00 0.500 Computed Peaks 1. 71 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-250.tsf Mean= 0.048 StdDev-0.126 Project Location:Sea-Tac Skew= 0. 396 B-66 SE u.f' Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 1.18 20 2/16/49 21:00 2.27 1 89.50 0.989 2 .21 2 3/03/50 16:00 2.21 2 32.13 0.969 1.27 18 2/09/51 2:00 2.02 3 19.58 0. 94 9 0.844 44 10/15/51 13: 00 1. 88 4 14.08 0.929 0.855 42 3/24/53 15:00 1.58 5 10.99 0.909 1. 08 26 12/19/53 19:00 1. 55 6 9.01 0. 889 1. 09 25 11/25/54 2:00 1. 48 7 7. 64 0.869 1.10 23 12/20/55 17:00 1.48 8 6. 63 0. 84 9 1.33 14 12/09/56 14:00 1. 4 6 9 5. 86 0. 829 1.12 21 12/25/57 16:00 1. 45 10 5.24 0.809 0.817 46 1/26/59 20:00 1.35 11 4.75 0. 789 1.11 22 11/20/59 5:00 1. 34 12 4. 34 0. 769 0.972 33 2/14/61 21: 00 1. 33 13 3. 99 0. 7 4 9 0 .912 39 11/22/61 2:00 1. 33 14 3.70 0. 729 0.982 31 12/15/62 2:00 1. 30 15 3.44 0. 709 1. 06 28 12/31/63 23:00 1. 30 16 3.22 0.690 0. 941 37 12/21/64 4:00 1. 28 17 3.03 0.670 0.967 35 1/05/66 16: 00 1.27 18 2. 85 0.650 1. 48 8 11/13/66 19:00 1. 23 19 2.70 0.630 1. 55 6 8/24/68 16:00 1.18 20 2.56 0.610 0.889 41 12/03/68 16:00 1.12 21 2.44 0.590 0. 979 32 1/13/70 22: 00 1.11 22 2.32 0.570 0.954 36 12/06/70 8:00 1.10 23 2.22 0.550 1. 58 5 2/27 /72 7:00 1. 09 24 2.13 0.530 0.845 43 1/13/73 2:00 1.09 25 2.04 0. 510 1. 08 27 11/28/73 9:00 1. 08 26 1. 96 0.490 1. 4 6 9 12/26/74 23:00 1. 08 27 1. 89 0.470 0.895 40 12/02/75 20:00 1. 06 28 1. 82 0.450 0. 936 38 8/26/77 2:00 1. 05 29 1. 75 0. 430 1. 35 11 9/22/78 19:00 1. 01 30 1. 70 0.410 1. 09 24 9/08/79 15:00 0.982 31 1. 64 0.390 1.30 16 12/14/79 21:00 0. 979 32 1. 59 0.370 1.30 15 11/21/80 11: 00 0. 972 33 1. 54 0.350 1. 88 4 10/06/81 15:00 0. 972 34 1. 49 0.330 1.23 19 10/28/82 16:00 0. 967 35 1. 45 0.310 1.05 29 1/03/84 1:00 0.954 36 1. 41 0.291 0.828 45 6/06/85 22:00 0. 941 37 1. 37 0.271 1. 33 13 1/18/86 16:00 0. 936 38 1. 33 0.251 1. 4 8 7 10/26/86 0:00 0.912 39 1. 30 0.231 0. 64 6 49 1/14/88 0:00 0.895 40 1. 27 0.211 0. 774 47 8/21/89 17:00 0. 88 9 41 1. 24 0 .191 2.27 1 1/09/90 6:00 0.855 42 1.21 0.171 2.02 3 11/24/90 8:00 0.845 43 1.18 0.151 1. 01 30 1/27/92 15:00 0.844 44 1.15 0.131 0,600 50 12/10/92 6:00 0.828 45 1.12 0.111 0.689 48 11/30/93 22:00 0.817 46 1.10 0 .091 0. 972 34 11/30/94 4:00 0.774 47 1. 08 0 .071 1. 45 10 2/08/96 10:00 0.689 48 1. 05 0.051 1.28 17 1/02/97 6:00 0.646 49 1. 03 0. 031 1. 34 12 10/04/97 15:00 0.600 50 1. 01 0.011 Computed Peaks 2.39 100.00 0.990 Computed Peaks 2.16 50.00 0.980 Computed Peaks 1. 93 25.00 0.960 Computed Peaks 1. 64 10.00 0.900 Computed Peaks 1.58 8.00 0.875 Computed Peaks 1. 42 5.00 0.800 B-67 SE 14,f' Street-June 2007 Computed Peaks 1.10 2.00 0.500 Computed Peaks 0.893 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-260.tsf Mean= -0.230 StdDev-0.124 Project Location:Sea-Tac Skew= 0.395 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.617 20 2/16/49 21:00 1.18 1 89.50 0.989 1.14 2 3/03/50 16:00 1.14 2 32.13 0. 969 0.660 18 2/09/51 2:00 1. 05 3 19.58 0. 94 9 0. 44 9 43 10/15/51 13:00 0.977 4 14.08 0.929 0.452 42 3/24/53 15:00 0.824 5 10.99 0.909 0.567 26 12/19/53 19:00 0.819 6 9.01 0.889 0 .572 25 11/25/54 2:00 0.788 7 7. 64 0. 8 69 0.574 24 12/20/55 17:00 0. 777 8 6.63 0.849 0.695 13 12/09/56 14:00 0.760 9 5.86 0. 82 9 0.590 21 12/25/57 16:00 0.752 10 5.24 0.809 0.430 46 11/18/58 13:00 0. 711 11 4.75 0.789 0.581 23 11/20/59 5:00 0.704 12 4. 34 0.769 0. 511 34 2/14/61 21:00 0.695 13 3. 99 0.749 0.483 39 11/22/61 2:00 0.695 14 3.70 0. 729 0.515 31 12/15/62 2:00 0.687 15 3.44 0.709 0.561 28 12/31/63 23:00 0.681 16 3.22 0.690 0.497 38 12/21/64 4:00 0.668 17 3.03 0.670 0.509 35 1/05/66 16:00 0.660 18 2.85 0.650 0. 777 8 11/13/66 19:00 0.655 19 2.70 0.630 0. 819 6 8/24/68 16:00 0. 61 7 20 2.56 0.610 0.467 41 12/03/68 16:00 0.590 21 2. 44 0.590 0.515 32 1/13/70 22:00 0.584 22 2. 32 0.570 0.500 36 12/06/70 8:00 0.581 23 2.22 0.550 0.824 5 2/27 /72 7:00 0.574 24 2.13 0.530 0.445 44 1/13/73 2:00 0.572 25 2.04 0. 510 0.564 27 11/28/73 9:00 0.567 26 1. 96 0.490 0.760 9 12/26/74 23:00 0. 564 27 1. 89 0.470 0.470 40 12/02/75 20:00 0.561 28 1. 82 0.450 0.499 37 8/26/77 2:00 0.550 29 1. 75 0.430 0. 711 11 9/22/78 19: 00 0.531 30 1. 70 0.410 0.584 22 9/08/79 15:00 0.515 31 1. 64 O. 390 0. 681 16 12/14/79 21:00 0.515 32 1. 59 0.370 0. 687 15 11/21/80 11 :00 0.514 33 1. 54 0.350 0. 977 4 10/06/81 15:00 0 .511 34 1. 49 0.330 0. 655 19 10/28/82 16:00 0.509 35 1. 45 0.310 0.550 29 1/03/84 1:00 0.500 36 1. 41 0.291 0.440 45 6/06/85 22:00 0.499 37 1. 37 0. 271 0.695 14 1/18/86 16:00 0.497 . 38 1. 33 0.251 0.788 7 10/26/86 0:00 0.483 39 1. 30 0.231 0.343 49 1/14/88 0:00 0.470 40 1. 27 0. 211 0.417 47 8/21/89 17:00 0.467 41 1.24 0.191 1.18 1 1/09/90 6:00 0.452 42 1.21 0.171 1. 05 3 11/24/90 8:00 0.449 43 1.18 0 .151 0.531 30 1/27/92 15:00 0.445 44 1.15 0 .131 0.318 so 12/10/92 6:00 0.440 45 1.12 0 .111 0.368 48 11/30/93 22:00 0.430 46 1.10 0.091 0.514 33 11/30/94 4:00 0.417 47 1. 08 0. 071 0.752 10 2/08/96 10:00 0. 368 48 1. 05 0.051 0. 668 17 1/02/97 6:00 0.343 49 1. 03 0.031 0.704 12 10/04/97 15:00 0.318 50 1. 01 0. 011 B-68 SE 14,f" Street-June 2007 Computed Peaks 1. 24 100.00 0.990 Computed Peaks 1.12 50.00 0.980 Computed Peaks 1. 01 25.00 0 .960 Computed Peaks 0.857 10.00 0.900 Computed Peaks 0.827 8.00 0.875 Computed Peaks 0. 743 5.00 0.800 Computed Peaks 0.577 2.00 0.500 Computed Peaks 0.472 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-260rd.tsf Mean= -0. 785 StdDev-0.291 Project Location:Sea-Tac Skew= 1.218 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0. 133 36 2/22/49 6:00 1.19 5.21 1 89.50 0.989 o. 179 14 3/05/50 7:00 0.942 5.17 2 32.13 0. 969 0.942 2 2/09/51 16:00 0.932 5.17 3 19.58 0. 94 9 0.081 42 2/04/52 9:00 0. 577 5 .11 4 14.08 0. 92 9 0.152 25 1/12/53 7:00 0.543 5.10 5 10.99 0.909 0 .14 5 31 1/06/54 12:00 0.439 5.07 6 9.01 0.889 0 .135 35 2/08/55 15:00 0.303 5.03 7 7.64 0.869 0.191 11 12/22/55 16:00 0.225 5.00 8 6.63 0. 84 9 0.142 33 2/26/57 4: 00 0.209 4.99 9 5.86 0.829 0.171 18 1/17/58 8: 00 0.200 4.74 10 5.24 0.809 0.125 39 1/24/59 18: 00 0 .191 4.51 11 4.75 0.789 0.577 4 11/21/59 2:00 0.183 4.32 12 4.34 0.769 0.168 19 11/24/60 17: DO 0.181 4.29 13 3.99 0. 74 9 0. 072 45 12/24/61 6:00 0.179 4.22 14 3.70 0. 72 9 0.156 22 11/26/62 11: 00 0 .178 4.21 15 3.44 0.709 0.152 26 11/19/63 18:00 0.173 4 .11 16 3.22 0.690 0 .183 12 12/01/64 8:00 0.172 4. 08 17 3.03 0. 670 0.140 34 1/07/66 3:00 0 .171 4.07 18 2.85 0.650 0 .172 17 12/13/66 15:00 0 .168 4. 00 19 2.70 0.630 0 .150 27 1/20/68 20:00 0 .162 3.89 20 2.56 0.610 0.133 37 12/11/68 7:00 0 .162 3.87 21 2.44 0.590 0 .145 32 1/27/70 4:00 0.156 3.77 22 2.32 0.570 0 .153 24 12/07 /70 11 :00 0.155 3.74 23 2.22 0.550 0. 209 9 3/07 /72 1:00 0.153 3. 71 24 2.13 0.530 0.173 16 12/27/72 19:00 0.152 3.69 25 2.04 0.510 0.155 23 1/16/74 19:00 0 .152 3.68 26 1. 96 0.490 0 .127 38 1/13/75 23:00 0.150 3.65 27 1. 89 0.470 0.150 28 12/04/75 4: 00 0.150 3.65 28 1. 82 0.450 0. 061 50 8/26/77 7:00 0.147 3.59 29 1. 75 0.430 0 .162 20 12/15/77 19:00 0.146 3.57 30 1. 70 0.410 0.066 48 2/13/79 12:00 0.145 3.56 31 1. 64 0.390 0.543 5 12/17/79 18:00 0.145 3.56 32 1. 59 0.370 0.147 29 12/30/80 21:00 0.142 3.52 33 1. 54 0.350 0.200 10 10/07/81 1:00 0.140 3.48 34 1. 4 9 0.330 0.146 30 1/06/83 14:00 0.135 3.40 35 1. 45 0.310 0.073 44 12/13/83 5:00 0 .133 3.38 36 1. 41 0.291 0.074 43 11/04/84 9:00 0.133 3.38 37 1. 37 0. 271 0.181 13 1/19/86 11: 00 0.127 3.28 38 1. 33 0.251 0.225 8 11/24/86 14:00 0.125 3.27 39 1. 30 0.231 0.109 40 12/09/87 23:00 0.109 3.09 40 1. 27 0 .211 0.071 46 11/06/88 0:00 0 .105 3. 04 41 1. 24 0 .191 1.19 1 1/09/90 10:00 0.081 2.96 42 1. 21 0 .171 0.303 7 4/05/91 7:00 0.074 2. 91 43 1.18 0.151 0.162 21 1/31/92 6:00 0.073 2.86 44 1.15 0 .131 B-69 SE J4.4'1' Street-June 2007 0.070 47 1/26/93 6:00 0. 072 2.80 45 1.12 0 .111 0.062 49 2/17/94 23:00 0.071 2.74 46 1.10 0. 091 0.178 15 12/27/91 20: 00 0.070 2.60 47 1. 08 0. 071 0. 932 3 2/09/96 2:00 0.066 2.38 48 1. 05 0.051 0.439 6 1/02/97 12:00 0.062 2.13 49 1. 03 0.031 0.105 41 1/24/98 23:00 0.061 1. 99 50 1. 01 0. 011 Computed Peaks 1. 36 5.24 100.00 0. 990 Computed Peaks 0.959 5.18 50.00 0.980 Computed Peaks 0.666 5.13 25.00 0. 960 Computed Peaks 0.403 5.06 10.00 0.900 Computed Peaks 0.364 5.05 8.00 0.875 Computed Peaks 0. 2 68 5.02 5.00 0. 800 Computed Peaks 0.144 3. 54 2.00 0.500 Computed Peaks 0.097 3.01 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-270. ts f Mean= -0.263 StdDev-0.125 Project Location:Sea-Tac Skew= 0. 392 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.573 20 2/16/49 21:00 1.10 1 89.50 0.989 1. 06 2 3/03/50 16:00 1. 06 2 32 .13 0. 969 0.614 18 2/09/51 2:00 0.982 3 19.58 0.949 0.415 43 10/15/51 13:00 0. 910 4 14.08 0.929 0.419 42 3/24/53 15:00 0.768 5 10.99 0.909 0.526 26 12/19/53 19:00 0.758 6 9.01 0.889 0.530 25 11/25/54 2:00 0. 728 7 7.64 0. 8 69 0.534 24 12/20/55 17:00 0. 721 8 6.63 0.849 0. 646 14 12/09/56 14:00 0.707 9 5.86 0.829 0.547 21 12/25/57 16:00 0.701 10 5.24 0.809 0.399 46 1/26/59 20:00 0.659 11 4.75 0.789 0.540 22 11/20/59 5:00 0.653 12 4.34 0.769 0.474 34 2/14/61 21 :00 0.647 13 3.99 0.749 0.447 39 11/22/61 2:00 0. 64 6 14 3.70 0. 729 0.479 31 12/15/62 2:00 0.637 15 3.44 0.709 0.520 28 12/31/63 23:00 0.633 16 3.22 0.690 0.460 38 12/21/64 4:00 0. 622 17 3.03 0. 670 0. 472 35 1/05/66 16:00 0.614 18 2.85 0.650 0.721 8 11/13/66 19:00 0.606 19 2.70 0.630 0.758 6 8/24/68 16:00 0.573 20 2.56 0.610 0. 433 41 12/03/68 16:00 0.547 21 2.44 0.590 0.478 32 1/13/70 22:00 0.540 22 2.32 0.570 0.464 36 12/06/70 8:00 0.539 23 2.22 0.550 0.768 5 2/27 /72 7:00 0.534 24 2.13 0.530 0. 413 44 1/13/73 2:00 0.530 25 2.04 0.510 0.524 27 11/28/73 9:00 0.526 26 1. 96 0.490 0.707 9 12/26/74 23:00 0.524 27 1. 89 0.470 0.436 40 12/02/75 20:00 0.520 28 1. 82 0.450 0.461 37 8/26/77 2:00 0.510 29 1. 75 0.430 0.659 11 9/22/78 19:00 0.492 30 1. 70 0.410 0.539 23 9/08/79 15:00 0.479 31 1. 64 0.390 0.633 16 12/14/79 21:00 0.478 32 1. 59 0.370 0.637 15 11/21/80 11: 00 0.476 33 1. 54 0.350 0.910 4 10/06/81 15:00 0.474 34 1. 49 0.330 0. 606 19 10/28/82 16: 00 0.472 35 1. 45 0.310 0.510 29 1/03/84 1:00 0.464 36 1. 41 0. 291 0.407 45 6/06/85 22:00 0. 4 61 37 1. 37 0.271 0.647 13 1/18/86 16:00 0.460 38 1. 33 0.251 B-70 SE I 4,f Streel-June 2007 0. 728 7 10/26/86 0:00 0.447 39 1. 30 0.231 0 .317 49 1/14/88 0:00 0.436 40 1. 27 0. 211 0.383 47 8/21/89 17:00 0.433 41 1. 24 0 .191 1.10 1 1/09/90 6:00 0.419 42 1.21 0.171 0.982 3 11/24/90 8: 00 0.415 43 1.18 0.151 0. 4 92 30 1/27 /92 15:00 0. 413 44 1.15 0 .131 0.294 50 12/10/92 6:00 0. 407 45 1.12 0 .111 0.339 48 11/30/93 22:00 0.399 46 1.10 0. 091 0.476 33 11/30/94 4:00 0.383 47 1. OB 0.071 0.701 10 2/08/96 10:00 0.339 48 1. 05 0.051 0. 622 17 1/02/97 6:00 0.317 49 1. 03 0.031 0.653 12 10/04/97 15:00 0. 2 94 50 1. 01 0.011 Computed Peaks 1.16 100.00 0.990 Computed Peaks 1. 04 SO.OD 0.980 Computed Peaks 0.936 25.00 0. 960 Computed Peaks 0. 7 97 10.00 0.900 Computed Peaks 0.769 8.00 0. 875 Computed Peaks 0. 690 5.00 0.800 Computed Peaks 0.536 2.00 0.500 Computed Peaks 0.437 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-300. tsf Mean= -0.057 StdDev-0 .172 Project Location:Sea-Tac Skew= 0.335 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 02 17 2/16/49 21:00 2.19 1 89.50 0.989 2.17 2 3/03/50 16:00 2.17 2 32 .13 0. 969 1.35 8 2/09/51 14:00 1. 90 3 19.58 0. 94 9 0.718 38 1/30/52 8:00 1.58 4 14.08 0. 929 0.602 42 3/24/53 15:00 1. 58 5 10.99 0. 90 9 0.842 21 12/19/53 19:00 1.50 6 9.01 0.889 1. 05 16 2/07/55 17:00 1. 36 7 7. 64 0. 8 69 1. 08 15 12/20/55 17:00 1. 35 8 6.63 0. 849 1.11 14 12/09/56 14:00 1.32 9 5.86 0. 829 0. 796 27 12/25/57 16:00 1. 20 10 5.24 0.809 0. 644 41 1/26/59 20:00 1.20 11 4.75 0. 789 1.14 13 11/20/59 21:00 1.15 12 4.34 0. 7 69 0. 775 32 2/14/61 21:00 1.14 13 3.99 0. 74 9 0.543 45 11/22/61 2:00 1.11 14 3. 7 0 o. 729 0. 7 91 29 12/15/62 2:00 1. 08 15 3.44 0.709 0.838 22 12/31/63 23:00 1. 05 16 3.22 0.690 0.672 40 12/21/64 4:00 1. 02 17 3.03 0.670 0. 771 34 1/05/66 16:00 1. 02 18 2.85 0.650 1. 20 11 1/19/67 14:00 0. 919 19 2.70 0.630 0. 919 19 8/24/68 16:00 0.855 20 2.56 0.610 0.763 35 12/03/68 16:00 0.842 21 2.44 0.590 0. 775 31 1/13/70 23:00 0.838 22 2.32 0.570 0. 774 33 12/06/70 8:00 0.831 23 2.22 0.550 1.50 6 2/27 /72 7:00 0.829 24 2.13 0.530 0.686 39 1/13/73 2:00 0.815 25 2.04 0.510 0.793 28 11/28/73 9:00 0.807 26 1. 96 0. 4 90 1.32 9 12/26/74 23:00 0. 796 27 1. 89 0.470 0.782 30 12/02/75 20:00 0. 793 28 1. 82 0.450 0.512 47 8/26/77 2:00 0. 791 29 1. 75 0. 430 0. 829 24 9/22/78 19:00 0.782 30 1. 70 0.410 0.563 44 9/08/79 15:00 0.775 31 1. 64 0.390 1.02 18 12/14/79 21: 00 0. 775 32 1. 59 0.370 B-71 SE 14.t' Street-June 2007 0.831 23 11/21/80 11 :00 0.774 33 1. 54 0. 350 1.58 4 10/06/81 15:00 0.771 34 1. 49 0.330 0.807 26 1/05/83 8:00 0.763 35 1. 45 0.310 0.815 25 1/03/84 1:00 0.762 36 1. 41 0. 2 91 0.469 48 6/06/85 22:00 0.759 37 1.37 0.271 1.36 7 1/18/86 16: 00 0. 718 38 1. 33 0. 251 1. 20 10 11/24/86 3:00 0.686 39 1.30 0. 231 0.539 46 1/14/88 12:00 0. 672 40 1.27 0.211 0.444 49 11/05/88 14:00 0.644 41 1.24 0 .191 2.19 1 1/09/90 6:00 0.602 42 1.21 0.171 1. 90 3 11/24/90 8:00 0.568 43 1.18 0 .151 0.759 37 1/27 /92 17:00 0.563 44 1.15 0.131 0.568 43 3/22/93 22:00 0.543 45 1.12 0.111 0.368 50 11/30/93 22:00 0.539 46 1.10 0.091 0.762 36 2/18/95 20:00 0.512 47 1. 08 0. 071 1.58 5 2/08/96 10:00 0.469 48 1. 05 0.051 1.15 12 1/02/97 6:00 0.444 49 1.03 0.031 0.855 20 10/04/97 15:00 0.368 50 1. 01 0.011 Computed Peaks 2.42 100. 00 0. 990 Computed Peaks 2.12 50. 00 0.980 Computed Peaks 1. 83 25. 00 0.960 Computed Peaks 1. 47 10.00 0.900 Computed Peaks 1. 40 8.00 0.875 Computed Peaks 1. 21 5.00 0.800 Computed Peaks 0.859 2.00 0.500 Computed Peaks 0.647 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-304.tsf Mean= 0 .141 StdDev-0.132 Project Location:Sea-Tac Skew= 0.426 ---Annual Peak Flow Rates--------Flow Frequency Analysis---~--- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.49 19 2/16/49 21:00 2. 93 1 89.50 0.989 2.86 2 3/03/50 16:00 2.86 2 32.13 0. 969 1. 65 13 2/09/51 2:00 2. 61 3 19.58 0.949 1.06 42 1/30/52 8:00 2.38 4 14.08 0.929 1.04 44 3/24/53 15:00 2.04 5 10.99 0.909 1. 34 25 12/19/53 19:00 1. 92 6 9.01 0.889 1. 40 22 2/07/55 17:00 1. 86 7 7. 64 0. 8 69 1. 42 21 12/20/55 17:00 1. 84 8 6.63 0.849 1. 67 12 12/09/56 14:00 1. 78 9 5.86 0. 82 9 1. 37 24 12/25/57 16:00 1. 75 10 5.24 0.809 1.01 45 1/26/59 20:00 1. 74 11 4.75 0.789 1.40 23 11/20/59 5:00 1. 67 12 4. 34 0.769 1.21 33 2/14/61 21:00 1. 65 13 3.99 0.749 1. 09 41 11/22/61 2:00 1. 63 14 3.70 0. 729 1.23 31 12/15/62 2:00 1. 62 15 3.44 0.709 1. 32 26 12/31/63 23:00 1. 62 16 3.22 0.690 1.15 37 12/21/64 4:00 1. 62 17 3.03 0.670 1.20 34 1/05/66 16:00 1.58 18 2. 85 0.650 1. 78 9 11/13/66 19:00 1. 49 19 2.70 0.630 1. 84 8 8/24/68 16:00 1. 47 20 2.56 0.610 1.12 39 12/03/68 16: 00 1. 42 21 2. 44 0. 590 1.22 32 1/13/70 22:00 1. 40 22 2. 32 0.570 1.20 35 12/06/70 8:00 1. 40 23 2.22 0.550 2.04 5 2/27 /72 7:00 1. 37 24 2.13 0.530 1. 06 43 1/13/73 2:00 1. 34 25 2.04 0.510 1.32 27 11/28/7 3 9:00 1. 32 26 1.96 0.490 B-72 SE 14¢>' Street-June 2007 1. 86 7 12 / 2 6/7 4 23:00 1.32 27 1. 8 9 0.470 1.14 38 12/02/75 20:00 1. 30 28 1. 82 0.450 1.10 40 8/26/77 2:00 1.27 29 1. 75 0.430 1. 62 15 9/22/78 19:00 1. 24 30 1.70 0.410 1.27 29 9/08/79 15:00 1. 23 31 1. 64 0.390 1. 62 17 12/14/79 21:00 1.22 32 1. 59 0.370 1. 58 18 11/21/80 11: 00 1. 21 33 1. 54 0.350 2.38 4 10/06/81 15:00 1. 20 34 1. 49 0.330 1. 47 20 10/28/82 16:00 1.20 35 1.45 0.310 1.30 28 1/03/84 1: 00 1. 17 36 1. 41 0. 291 0.978 46 6/06/85 22:00 1.15 37 1. 37 0. 271 1. 75 10 1/18/86 16:00 1.14 38 1.33 0.251 1. 74 11 10/26/86 0:00 1.12 39 1. 30 0.231 0.782 49 1/14/88 12:00 1 .10 40 1.27 0 .211 0.897 47 8/21/89 17:00 1. 09 41 1.24 0 .191 2.93 1 1/09/90 6:00 1. 06 42 1. 21 0.171 2.61 3 11/24/90 8:00 1. 06 43 1.18 0.151 1. 24 30 1/27/92 15:00 1. 04 44 1.15 0.131 0.756 50 3/22/93 22:00 1.01 45 1.12 0 .111 0.806 48 11/30/93 22:00 0. 978 46 1.10 0.091 1.17 36 11/30/94 4:00 0.897 47 1. 08 0.071 1. 92 6 2/08/96 10:00 0. 806 48 1. 05 0.051 1. 63 14 1/02/97 6:00 0.782 49 1. 03 0.031 1. 62 16 10/04/97 15:00 0.756 50 1.01 0 .011 Computed Peaks 3.09 100.00 0.990 Computed Peaks 2.77 50.00 0.980 Computed Peaks 2.46 25.00 0. 960 Computed Peaks 2.07 10.00 0.900 Computed Peaks 1. 99 8.00 0.875 Computed Peaks 1.77 5.00 0.800 Computed Peaks 1. 36 2.00 0.500 Computed Peaks 1. 09 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-306 .. tsf Mean= -1.180 StdDev-0.204 Project Location:Sea-Tac Skew= 0.041 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.081 17 2/16/49 21:00 0.177 l 89.50 0. 989 0.176 2 3/03/50 16:00 0.176 2 32 .13 0.969 0 .126 5 2/09/51 15:00 0.153 3 19.58 0.949 0. 056 37 1/30/52 8:00 0.136 4 14.08 0.929 0.042 44 3/24/53 15:00 0 .12 6 5 10.99 0.909 0. 062 23 12/19/53 19:00 0.122 6 9.01 0.889 0.087 15 2/07/55 19:00 0.118 7 7. 64 0.869 0.089 14 12/20/55 17: 00 0.115 8 6.63 0.849 0.085 16 12/09/56 14:00 0.104 9 5. 8 6 0.829 0.064 21 1/16/58 16:00 0.100 10 5.24 0.809 0.052 40 1/23/59 23:00 0.100 11 4.75 0.789 0 .100 10 11/20/59 21:00 0.100 12 4.34 0.769 0.058 31 2/14/61 21:00 0. 0 92 13 3.99 0.749 0.037 45 1/02/62 22:00 0. 08 9 14 3.70 0. 729 0.059 30 12/15/62 2:00 0.087 15 3.44 0.709 0 .062 22 12/31/63 23:00 0.085 16 3.22 0.690 0 .047 42 12/21/64 4:00 0.081 17 3.03 0.670 0.058 32 1/05/66 16:00 0.073 18 2. 85 0.650 0.100 11 1/19/67 14:00 0.069 19 2. 70 0.630 0.060 25 2/03/68 22:00 0.067 20 2.56 0.610 B-73 SE 144"' Street-June 2007 0.060 27 12/03/68 16:00 0.064 21 2.44 0.590 0.060 28 1/13/70 23:00 0.062 22 2.32 0.570 0.058 33 12/06/70 8:00 0.062 23 2.22 0.550 0.122 6 2/28/72 3:00 0.061 24 2.13 0.530 0.053 38 1/13/73 4:00 0.060 25 2.04 0.510 0.057 34 1/15/74 2:00 0.060 26 1. 96 0. 4 90 0.104 9 12/26/74 23:00 0.060 27 1. 89 0. 4 70 0.061 24 12/02/75 20:00 0.060 28 1. 82 0.450 0.029 48 8/26/77 2:00 0.059 29 1. 75 0. 4 30 0.057 35 12/10/77 17: 00 0.059 30 1. 70 0. 410 0.031 47 11/19/78 3:00 0.058 31 1. 64 0. 390 0.073 18 12/14/79 21:00 0.058 32 1. 59 0. 370 0.056 36 12/26/80 0:00 0.058 33 1. 54 0. 350 0.118 7 10/06/81 15:00 0.057 34 1. 49 0.330 0.069 19 1/05/83 8:00 0.057 35 1.45 0.310 0.060 26 1/03/84 1:00 0.056 36 1. 41 0. 2 91 0.031 46 2/11/85 3:00 0.056 37 1. 37 0 .271 0 .115 8 1/18/86 16: 00 0.053 38 1. 33 0. 251 0.100 12 11/24/86 4:00 0.052 39 1. 30 0.231 0.043 43 1/14/88 12:00 0.052 40 1. 27 0. 211 0.027 49 12/30/88 5:00 0.048 41 1. 24 0 .191 0.177 1 1/09/90 6:00 0.047 42 1.21 0.171 0.153 3 11/24/90 8:00 0.043 43 1. 18 0.151 0. 059 29 1/27/92 17:00 0.042 44 1.15 0 .131 0.048 41 3/22/93 23:00 0.037 45 1.12 0 .111 0.023 50 2/17 /94 18:00 0.031 46 1.10 0. 0 91 0.067 20 2/19/95 18:00 0.031 47 1. 08 0.071 0 .136 4 2/08/96 10:00 0.029 48 1. 05 0.051 0.092 13 1/02/97 6:00 0.027 49 1. 03 0.031 0.052 39 10/04/97 15:00 0.023 50 1.01 0 .011 Computed Peaks 0.200 100.00 0.990 Computed Peaks 0 .176 50.00 0.980 Computed Peaks 0.152 25.00 0. 960 computed Peaks 0.121 10.00 0.900 Computed Peaks 0.115 8.00 0.875 Computed Peaks 0.098 5.00 0.800 computed Peaks 0.066 2.00 0.500 Computed Peaks 0.046 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-310.tsf Mean= -0.648 StdDev= 0.233 Project Location:Sea-Tac Skew= -0.139 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.276 16 2/16/49 22:00 0. 627 1 89.50 0.989 0.539 5 3/03/50 16:00 0. 592 2 32.13 0.969 0. 592 2 2/09/51 18:00 0.561 3 19.58 0. 94 9 0.186 32 1/30/52 9:00 0.549 4 14. 08 0. 92 9 0.143 42 1/18/53 19:00 0.539 5 10.99 0.909 0.208 28 1/06/54 5:00 0.456 6 9.01 0.889 0.368 9 2/07/55 21:00 0.440 7 7.64 0.869 0.313 13 12/20/55 17: 00 0.396 8 6.63 0.849 0.244 21 12/09/56 15:00 0.368 9 5. 86 0. 829 0.259 20 1/16/58 20:00 0.368 10 5.24 0.809 0.212 24 1/24/59 2:00 0. 364 11 4.75 0.789 0.396 8 11/20/59 21:00 0. 317 12 4.34 0. 769 0. 215 23 2/24/61 15:00 0 .313 13 3. 99 0.749 0.129 44 1/03/62 2:00 0.306 14 3.70 0. 729 B-74 SE 144"' Streer-June 2007 0 .171 36 11/25/62 15:00 0.285 15 3.44 0.'/09 0.212 25 1/01/64 18:00 0. 276 16 3 .22 0. 690 0.150 40 11/30/64 12: 0 0 0.273 17 3.03 0.670 0.163 38 1/06/66 3:00 0.273 18 2.85 0.650 0.364 11 1/19/67 14:00 0.265 19 2.70 0.630 0.216 22 2/03/68 23:00 0.259 20 2.56 0.610 0 .211 27 12/03/68 17:00 0.244 21 2.44 0.590 0.179 34 1/13/70 23:00 0.216 22 2.32 0.570 0 .145 41 12/06/70 8:00 0.215 23 2.22 0.550 0.440 7 2/28/72 3:00 0. 212 24 2.13 0.530 0.195 30 1/13/73 5:00 0.212 25 2.04 0.510 0.212 26 1/15/74 2:00 0.212 26 1. 96 0. 4 90 0.317 12 12/26/74 23 :00 0 .211 27 1.89 0.470 0 .196 29 12/03/75 17:00 0.208 28 1. 82 0. 450 0.022 50 3/24/77 20:00 0.196 29 1. 75 0.430 0.169 37 12/10/77 17: 00 0 .195 30 1. 70 0.410 0.102 46 2/12/79 8:00 0.190 31 1. 64 0.390 0.273 18 12/15/79 8:00 0 .186 32 1. 59 0.370 0.151 39 12/26/80 4:00 0.183 33 1.54 0.350 0.273 17 10/06/81 15:00 0.179 34 1.49 0.330 0.265 19 1/05/83 8:00 0.177 35 1. 45 0.310 0.177 35 1/24/84 11 :00 0.171 36 1. 41 0. 291 0.085 48 2/11/85 6:00 0.169 37 1.37 0.271 0.456 6 1/18/86 21:00 0 .163 38 1. 33 0.251 0.368 10 11/24/86 4:00 0.151 39 1. 30 0. 2 31 0.139 43 1/14/88 12:00 0.150 40 1.27 0. 211 0.088 47 4/05/89 16:00 0.145 41 1.24 0 .191 0. 627 1 1/09/90 9:00 0.143 42 1.21 0.171 0. 54 9 4 4/05/91 2:00 0.139 43 1.18 0.151 0.183 33 1/27/92 17:00 0 .129 44 1. 15 0.131 0.190 31 3/23/93 0:00 0.107 45 1.12 0 .111 0.053 49 3/03/94 4:00 0.102 46 1.10 0. 091 0.285 15 2/19/95 20:00 0.088 47 1. 08 0.071 0. 561 3 2/09/96 1:00 0.085 48 1.05 0.051 0. 306 14 1/02/97 9:00 0.053 49 1. 03 0.031 0.107 45 1/07 /98 10:00 0.022 so 1. 01 0. 011 Computed Peaks 0.743 100.00 0.990 Computed Peaks 0.651 50.00 0.980 Computed Peaks 0.561 25.00 0.960 Computed Peaks 0.444 10.00 0.900 Computed Peaks ·o. 420 8.00 0.875 Computed Peaks 0.355 5.00 0.800 Computed Peaks 0.228 2.00 0.500 Computed Peaks 0.151 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-320.tsf Mean= -0.597 StdDev= 0.226 Project Location:Sea-Tac Skew~ -0.141 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.312 16 2/16/49 22: 00 0.692 1 89. 50 0.989 0.636 2 3/03/50 16:00 0.636 2 32 .13 0. 969 0.621 3 2/09/51 18:00 0.621 3 19.58 0.949 0.207 33 1/30/52 8:00 0.595 4 14.08 0.929 0 .161 42 1/18/53 19:00 0.586 5 10.99 0.909 0.223 29 1/22/54 20:00 0. 4 95 6 9.01 0.889 0. 392 11 2/07/55 21:00 0.485 7 7. 64 0.869 0.354 14 12/20/55 17:00 0. 4 34 8 6.63 0. 84 9 B-75 SE 144°' Street-June 2007 0.284 20 12/09/56 14:00 0. 411 9 5. 8 6 0.829 0.275 21 1/16/58 20: 00 0.408 10 5.24 0.809 0.227 28 1/24/59 2:00 0. 392 11 4.75 0.789 0.434 8 11/20/59 21:00 0.375 12 4.34 0.769 0.227 26 2/24/61 15:00 0.356 13 3.99 0.749 0.142 44 1/02/62 22:00 0.354 14 3.70 0. 729 0.192 36 11/25/62 14 :00 0.339 15 3.44 0. 709 0.234 25 1/01/64 14:00 0. 312 16 3.22 0.690 0.167 41 11/30/64 22:00 0.301 17 3.03 0.670 0.191 37 1/05/66 16:00 0. 295 18 2.85 0.650 0.408 10 1/19/67 14:00 0.293 19 2.70 0.630 0.239 22 2/03/68 22:00 0.284 20 2.56 0.610 0.237 23 12/03/68 17:00 0.275 21 2. 4 4 0.590 0.212 32 1/13/70 23:00 0.239 22 2.32 0.570 0.183 39 12/06/70 8:00 0.237 23 2.22 0.550 0.495 6 2/28/72 3:00 0.235 24 2.13 0.530 0. 215 30 1/13/73 5:00 0.234 25 2.04 0.510 0.235 24 1/15/74 2:00 0.227 26 1.96 0 .490 0.375 12 12/26/74 23:00 0.227 27 1. 89 0.470 0.227 27 12/02/75 20:00 0.227 28 1.82 0. 450 0. 047 50 3/24/77 19: 00 0.223 29 1. 75 0. 430 0.201 35 12 / 10 /7 7 17:00 0.215 30 1. 70 0.410 0 .114 46 2/12/79 7:00 0.215 31 1. 64 0.390 0.295 18 12/15/79 8:00 0.212 32 1. 59 0.370 0.180 40 12/26/80 0:00 0.207 33 1. 54 0.350 0.356 13 10/06/81 15:00 0.207 34 1. 4 9 0.330 0.293 19 1/05/83 8:00 0.201 35 1. 45 0.310 0.190 38 1/24/84 11 :00 0 .192 36 1. 41 0.291 0.095 48 2/11/85 5:00 0.191 37 1. 37 0 .271 0.485 7 1/18/86 20:00 0 .190 38 1.33 0.251 0 .411 9 11/24/86 4:00 0.183 39 1. 30 0.231 0.161 43 1/14/88 12:00 0.180 40 1.27 0.211 0.098 47 4/05/89 16:00 0 .167 41 1.24 0.191 0.692 1 1/09/90 9:00 0.161 42 1.21 0 .1 71 0.586 5 4/05/91 2:00 0.161 43 1.18 0.151 0.215 31 1/27 /92 17:00 0.142 44 1.15 0 .131 0.207 34 3/22/93 23:00 0.132 45 1.12 0 .111 0.063 49 2/17/94 18:00 0 .114 46 1.10 0.091 0.301 17 2/19/95 18:00 0.098 47 1. 08 0 .071 0.595 4 2/09/96 1:00 0.095 48 1. 05 0.051 0.339 15 1/02/97 9:00 0.063 49 1. 03 0.031 0 .132 45 10/30/97 7:00 0.047 50 1. 01 0.011 Computed Peaks 0.806 100.00 0.990 Computed Peaks 0.709 50.00 0.980 Computed Peaks 0.614 25.00 0.960 Computed Peaks 0.489 10.00 0.900 Computed Peaks 0.463 8.00 0.875 Computed Peaks 0.394 5.00 0.800 Computed Peaks 0.256 2.00 0.500 Computed Peaks 0 .171 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-330.tsf Mean= -0.930 StdDev~ 0.187 Project Location:Sea-Tac Skew= 0.198 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.139 17 2/16/49 21:00 0.307 1 89.50 0.989 0. 307 2 3/03/50 16:00 0.307 2 32 .13 0. 969 B-76 SE 144"' Street-June 2007 0.193 7 2/09/51 14:00 0. 265 3 19.58 0.949 0. 097 38 1/30/52 8:00 0.222 4 14.08 O. 929 0.078 43 3/24/53 15:00 0.218 5 10.99 0.909 0.112 20 12/19/53 19:00 0.208 6 9.01 0.889 0.144 16 2/07/55 17:00 0.193 7 7.64 0. 8 69 0.149 15 12/20/55 17:00 0 .190 8 6.63 0. 84 9 0.152 14 12/09/56 14:00 0.182 9 5.86 0.829 0.107 26 1/16/58 16:00 0.167 10 5.24 0.809 0.087 41 1/23/59 23:00 0.166 11 4.75 0. 789 0 .162 12 11/20/59 21:00 0.162 12 4.34 0. 7 69 0.103 34 2/14/61 21 :00 0.158 13 3.99 0.749 0. 068 45 11/22/61 2:00 0.152 14 3.70 0. 729 0.107 27 12 /15 / 62 2:00 0.149 15 3. 44 0. 709 0.111 23 12/31/63 23:00 0.144 16 3.22 0.690 0.087 40 12/21/64 4:00 0 .139 17 3.03 0.670 0.103 35 1/05/66 16:00 0.137 18 2.85 0.650 0.166 11 1/19/67 14:00 0 .116 19 2.70 0.630 0 .116 19 8/24/68 16:00 0.112 20 2.56 0.610 0.103 36 12/03/68 16:00 0 .112 21 2.44 0. 5 90 0.104 33 1/13/70 23:00 0 .112 22 2.32 0.570 0.105 32 12/06/70 8:00 0 .111 23 2.22 0.550 0.208 6 2/27 /72 7:00 0.109 24 2 .13 0.530 0 .092 39 1/13/73 2:00 0.108 25 2.04 0.510 0.106 29 11/28/73 9:00 0.107 26 1. 96 0. 4 90 0.182 -9 12/26/74 23:00 0.107 27 1. 89 0. 4 70 0.106 30 12/02/75 20:00 0.106 28 1.82 0.450 0. 0 61 47 8/26/77 2:00 0.106 29 1. 7 5 0. 4 30 0 .10 6 28 9/22/78 19:00 0.106 30 1. 70 0. 410 0.065 46 9/08/7 9 15:00 0.106 31 1. 64 0.390 0 .137 18 12/14/79 21:00 0.105 32 1. 59 0.370 0.108 25 11/21 /80 11:00 0.104 33 1. 54 0.350 0.218 5 10/06/81 15:00 0.103 34 1. 49 0.330 0.112 21 1/05/83 8:00 0.103 35 1. 45 0.310 0 .10 9 24 1/03/84 1:00 0.103 36 1.41 0 .291 0.058 48 2/11/85 3:00 0.102 37 1.37 0.271 0 .190 8 1/18/86 16:00 0. 0 97 38 1. 33 0.251 0 .167 10 11/24/86 3:00 0.092 39 1. 30 0 .231 0.073 44 1/14/88 12:00 0.087 40 1.27 0.211 0.056 49 11/05/88 14 :00 0.087 41 1.24 0 .191 0.307 1 1/09/90 6:00 0.078 42 1.21 0 .171 0.265 3 11/24/90 8:00 0.078 43 1.18 0.151 0 .102 37 1/27 /92 17:00 0.073 44 1.15 0.131 0.078 42 3/22/93 22: 00 0.068 45 1.12 0 .111 0.043 50 11/30/93 22:00 0.065 46 1.10 0.091 0 .106 31 2/19/95 17:00 0.061 47 1.08 0.071 0.222 4 2/08/96 10:00 0.058 48 1. 05 0.051 0.158 13 1/02/97 6:00 0.056 49 1. 03 0.031 0.112 22 10/04/97 15:00 0.043 50 1.01 0 .011 Computed Peaks 0.341 100.00 0.990 Computed Peaks 0 .298 50.00 0.980 Computed Peaks 0.257 25.00 0. 960 Computed Peaks 0.206 10.00 0.900 Computed Peaks 0.196 8.00 0.875 Computed Peaks 0 .168 5.00 0.800 Computed Peaks 0 .116 2.00 0.500 Computed Peaks 0.084 1. 30 0.231 Flow Frequency Analysls LogPearson III Coefficients Time Series File:cb4a.tsf Mean= 0.641 StdDev-0.148 Project Location:Sea-Tac Skew= 0.477 B-77 SE 14.f' Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 4.78 21 2/16/49 21: 00 10.01 1 89.50 0.989 9.85 2 3/03/50 16:00 9.85 2 32 .13 0. 969 5.62 9 2/09/51 2:00 8.83 3 19.58 0.949 3.39 39 1/30/52 8:00 8.04 4 14.08 0. 929 3.11 44 3/24/53 15:00 6.85 5 10.99 0.909 4 .19 24 12/19/53 19:00 6.76 6 9.01 0.889 4. 71 22 2/07/55 17:00 6.21 7 7. 64 0.869 4.82 20 12/20/55 17:00 6.01 8 6.63 0.849 5.41 12 12/09/56 14:00 5. 62 9 5. 8 6 0.829 4 .19 25 12/25/57 16:00 5.52 10 5.24 0.809 3.16 43 1/26/59 20:00 5.49 11 4.75 0.789 4.92 18 11/20/59 21:00 5.41 12 4.34 0. 7 69 3.78 34 2/14/61 21:00 5.37 13 3.99 0.749 3 .20 42 11/22/61 2:00 5.35 14 3.70 0. 729 3.90 29 12/15/62 2:00 5.16 15 3.44 0.709 4 .13 26 12/31/63 23:00 4. 98 16 3.22 0.690 3. 4 9 37 12/21/64 4:00 4. 92 17 3.03 0. 670 3. 79 33 1/05/66 16:00 4. 92 18 2.85 0.650 5. 49 11 11/13/66 19:00 4. 84 19 2.70 0.630 5.35 14 8/24/68 16:00 4. 82 20 2.56 0.610 3. 62 36 12/03/68 16: 00 4.78 21 2.44 0.590 3.85 32 1/13/70 22:00 4. 71 22 2.32 0.570 3.87 30 12/06/70 8:00 4.23 23 2.22 0.550 6.85 5 2/27 /72 7:00 4.19 24 2.13 0.530 3.34 41 1/13/73 2:00 4.19 25 2.04 0.510 4 .11 27 11/28/73 9:00 4 .13 26 1. 96 0. 4 90 6.21 7 12/26/74 23:00 4 .11 27 1. 8 9 0.470 3.70 35 12/02/75 20:00 4. 07 28 1. 82 0.450 3.05 45 8/26/77 2:00 3. 90 29 1. 7 5 0.430 4. 92 17 9/22/78 19:00 3.87 30 1. 70 0.410 3.38 40 9/08/79 15:00 3.86 31 1. 64 0.390 5.16 15 12/14/79 21: 00 3. 85 32 1. 59 0.370 4.84 19 11/21/80 11: 00 3.79 33 1. 54 0.350 8.04 4 10/06/81 15:00 3.78 34 1. 4 9 0.330 4.23 23 10/28/82 16: 00 3.70 35 1. 45 0.310 4.07 28 1/03/84 1:00 3. 62 36 1. 41 0.291 2.75 46 6/06/85 22:00 3.49 37 l. 37 0.271 6.01 8 1/18/86 16:00 3.48 38 1. 33 0.251 5.52 10 11/24/86 3:00 3.39 39 1. 30 0.231 2.57 48 1/14/88 12:00 3.38 40 1. 27 0.211 2.63 47 11/05/88 14: 00 3.34 41 1.24 0 .191 10.01 1 1/09/90 6:00 3.20 42 1. 21 0 .171 8.83 3 11/24/90 8:00 3.16 43 1.18 0.151 3.86 31 1/27 /92 15:00 3.11 44 1.15 0 .1'31 2.55 49 3/22/93 22:00 3. 05 45 1.12 0 .111 2.19 50 11/30/93 22:00 2.75 46 1.10 0.091 3.48 38 11/30/94 4:00 2. 63 47 1. 08 0.071 6.76 6 2/08/96 10:00 2.57 48 1. 05 0.051 5.37 13 1/02/97 6:00 2.55 49 1. 03 0.031 4. 98 16 10/04/97 15:00 2 .19 50 1. 01 0.011 Computed Peaks 10.86 100.00 0.990 Computed Peaks 9.57 50.00 0.980 Computed Peaks 8.36 25.00 0.960 Computed Peaks 6.86 10.00 0.900 Computed Peaks 6.57 8.00 0.875 Computed Peaks 5. 7 6 5.00 0.800 B-78 SE J4,f' Street-June 2007 Computed Peaks 4.25 2.00 0.500 Computed Peaks 3.35 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series 2ile:cbl8a.tsf Mean= 1.006 StdDev-0.144 Project Location:Sea-Tac Skew= 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 11.14 18 2/16/49 21:00 22.43 1 89.50 0.989 21. 83 2 3/03/50 16:00 21. 83 2 32.13 0. 969 14. 72 7 2/09/51 15:00 19.81 3 19. 58 0. 94 9 8.02 38 1 /30/52 8:00 18.28 4 14. 08 0.929 7 .15 45 3/24/53 15:00 16.05 5 10.99 0.909 9.63 23 12/19/53 19:00 15.54 6 9.01 0.889 11. 00 19 2/07/55 17: 00 14. 72 7 7.64 0.869 11. 33 17 12/20/55 17: 00 14. 05 8 6.63 0.849 12.33 14 12/09/56 14:00 13.90 9 5.86 0. 829 9.52 25 12/25/57 16:00 13.36 10 5.24 0.809 7.42 42 1/26/59 20:00 12.80 11 4.75 0.789 12. 72 12 11/20/59 21:00 12.72 12 4.34 0.769 8 _·7 6 34 2/14/61 21:00 12.37 13 3.99 0. 74 9 7.24 43 11/22/61 2:00 12.33 14 3.70 0. 729 8.93 30 12/15/62 2:00 11. 96 15 3.44 0. 709 9. 51 26 12/31/63 23:00 11. 67 16 3.22 0.690 8.01 39 12/21/64 4:00 11. 33 17 3.03 0.670 8. 86 32 1/05/66 16:00 11.14 18 2.85 0.650 12.37 13 1/19/67 14:00 11. 00 19 2. 70 0.630 11. 96 15 8/24/68 16:00 10.83 20 2.56 0.610 8.55 36 12/03/68 16:00 10. 7 5 21 2.44 0.590 8.89 31 1/13/70 22:00 10.65 22 2.32 0.570 9.00 29 12/06/70 8:00 9.63 23 2 .22 0.550 15. 54 6 2/27/72 7:00 9.57 24 2.13 0.530 7. 85 41 1/13/73 2:00 9.52 25 2. 04 0.510 9.13 28 11/28/73 9:00 9.51 26 1. 96 0. 4 90 14.05 8 12/26/74 23:00 9.24 27 1. 8 9 0.470 8. 70 35 12/02/75 20:00 9.13 28 1. 82 0. 450 7. 23 44 8/26/77 2:00 9.00 29 1. 7 5 0.430 10.83 20 9/22/78 19:00 8.93 30 1. 70 0.410 7. 86 40 9/08/79 15:00 8.89 31 1. 64 0.390 11. 67 16 12/14/79 21:00 8.86 32 1. 59 0.370 10. 65 22 11/21/80 11: 00 8.84 33 1. 54 0.350 18. 28 4 10/06/81 15:00 8.76 34 1. 49 0.330 9.57 24 10/28/82 16:00 8.70 35 1. 45 0.310 9.24 27 1/03/84 1:00 8.55 36 1.41 0.291 6.55 46 6/06/85 22:00 8.31 37 1. 37 0.271 13.90 9 1/18/86 16:00 8. 02 38 1. 33 0.251 13.36 10 11/24/86 4: 00 8. 01 39 1. 30 0.231 6.18 48 1/14/88 12:00 7.86 40 1.27 0. 211 6.12 49 11/05/88 14:00 7.85 41 1.24 0 .191 22 .43 1 1/09/90 6:00 7.42 42 1. 21 0 .171 19.81 3 11/24/90 8:00 7.24 43 1.18 0.151 8.84 33 1/27 /92 15:00 7.23 44 1.15 0.131 6. 20 47 3/22/93 22:00 7.15 45 1.12 0 .111 5 .26 so 11/30/93 22:00 6.55 46 1.10 0.091 8.31 37 12/27/94 1:00 6.20 47 1. 08 0.071 16 .05 5 2/08/96 10:00 6.18 48 1. 05 0.051 12.80 11 1/02/97 6:00 6.12 49 1. 03 0.031 10.75 21 10/04/97 15:00 5. 2 6 so 1. 01 0. 011 B-79 SE 144"' Street-June 2007 Computed Peaks 24.66 100.00 0.990 Computed Peaks 21. 7 8 SO.OD 0.980 Computed Peaks 19.08 25.00 0. 960 Computed Peaks 15.70 10.00 0.900 Computed Peaks 15.05 8.00 0. 875 Computed Peaks 13.24 5.00 0.800 Computed Peaks 9.86 2.00 0.500 Computed Peaks 7.83 1. 30 0 .231 B-80 SE 14,,f' Street-June 2007 Appendix C. XP-SWMM Model Results SE 14¢1' Street-June 2007 Table C.1. XP-Storm Conveyance Reach Descriptions Upstream Upstream Invert Downstream Link Node Downstream Elevation Invert Diameter Name Name Node Name Length ft Roughness ft Elevation ft Shape (Height) ft P01 CB1 DS 200.00 0.02 355.41 335.00 Circular 2.00 P02 CB2 CB1 200.00 0.02 359.42 357.41 Circular 2.00 P04 CB3 CB2 220.00 0.02 361.55 359.52 Circular 2.00 P06 CB4 CB3 210.00 O.o2 363.83 361.60 Circular 2.00 P10 CB5 CB4 42.00 O.o2 363.88 363.98 Circular 2.00 P12 CB6 CB5 44.00 0.02 364.11 364.13 Circular 2.00 P14 CB7 CB6 150.30 O.o2 364.93 364.31 Circular 1.50 P16 CB8 CB7 169.30 O.o2 365.45 364.99 Circular 1.50 P19 CB9A CB9 50.00 0.01 366.73 366.33 Circular 1.00 P18 CB9 CB8 168.30 0.02 365.93 365.50 Circular 1.50 P20 CB10 CB9 182.40 0.02 366.45 365.98 Circular 1.50 P21 CB10A CB10 39.00 O.o2 367.11 366.92 Circular 1.00 P22 CB11 C810 141.60 0.02 366.95 366.48 Circular 1.50 P70 CB11A CB11 34.00 0.02 367.63 367.49 Circular 1.00 MU1tA CB11A CB10A 120.00 0.01 370.48 370.24 Trapezoidc 0.30 MU11B CB118 CB11A 160.00 0.01 370.50 370.38 Trapezoid< 0.40 MU11B CB118 CB11A 160.00 0.01 370.60 370.48 Trapezoidc 0.30 P24 CB12 CB11 169.30 0.02 367.52 367.00 Circular 1.50 P26 CB13 CB12 142.40 0.02 367.85 367.52 Circular 1.50 P50 CB14A C814 52.00 O.Q1 369.46 369.25 Circular 1.00 ST14A CB14A CB11B 260.00 0.01 371.39 370.70 Trapezoidc 0.20 P28 CB14 CB13 115.00 0.02 368.15 367.92 Circular 1.50 P30 CB15 CB14 34.00 0.02 368.42 368.20 Circular 1.50 P60 CB15A CB15 52.00 O.Q1 369.19 368.87 Circular 1.00 OV15A CB15A CB14A 38.00 O.Q1 371.41 371.39 Trapezoidc 0.20 P54 CB14C CB14B 105.00 0.01 370.25 369.89 Circular 1.00 P64 CB15C C815B 105.00 O.Q1 373.17 371.37 Circular 1.00 P66 CB15D CB15C 60.00 0.0, 379.23 373.30 Circular 1.00 P32 CB16 CB15 197.40 0.02 369.15 368.52 Circular 1.50 P34 CB17 CB16 300.50 0.02 371.76 370.27 Circular 1.50 P36 CB18 CB17 118.30 0.02 372.98 372.41 Circular 1.50 P37 CB18A CB18 37.00 0.02 373.91 374.13 Circular 1.50 D1 CB18A N15A-2 10.00 0.03 375.50 375.40 Trapezoidc 0.50 P38 CB19 CB18 198.50 0.02 374.69 373.83 Circular 1.00 P40 CB20 CB19 247.50 0.02 375.98 374.74 Circular 1.00 P42 CB21 CB20 192.20 0.02 376.95 375.98 Circular 1.00 P08 CB4A CB4 190.00 0.02 366. 18 364.73 Circular 1.50 P52 CB14B CB14A 28.00 0.01 369.89 369.49 Circular 1.00 P62 CB15B CB15A 142.00 0.01 371.32 369.39 Circular 1.00 P61 CB15A·1 CB15A 20.00 0.01 370.20 369.27 Circular 1.00 P61 CB15A-1 CB15A 20.00 0.01 372.03 371.31 Trapezoidc 0.30 POSA CB4B CB4A 190.00 0.02 367.26 366.18 Circular 1.50 POBB CB4C CB4B 25.00 0.02 367.63 367.26 Circular 1.50 D2 N15A·2 CB15A·1 590.00 0.03 376.00 370.20 Natural 2.00 Table C.2. XP-Storm Inflows -25-Year Peak Rates Node Name Constant Inflow ftA3/s CB1 CB2 CB3 CB4 CBS CB6 CB7 0.045 0.206 0.242 CB8 0.198 CB9A 0.297 CB9 CB10 CB10A CB11 0.126 CB11A CB118 CB12 CB13 CB14A CB14 0.200 CB15 0.588 CB15A 0.724 CB14C 0.388 CB15C CB15D CB16 CB17 C818 0.204 CB18A 19.080 CB19 CB20 CB21 0.157 CB4A CB14B CB15B OS CB15A-1 CB48 CB4C 8.360 N15A-2 Table C.3. XP-Stonn 25-Year Water Surface Elevations Ground Max Elevation Water Node (Spill Elevation Freeboard Name Name Crest) ft (fl) (fl) C81 CB1 362.33 356.168 6.16 CB2 CB2 363.47 361.096 2.37 CB3 CB3 365.3 363.217 2.08 C84 CB4 368.98 365.394 3.59 CB5 CBS 369.38 365.546 3.83 CB6 CB6 368.31 365.711 2.6 CB7 CB7 368.87 366.833 2.04 CB8 CB8 369.4 368.097 1.3 CB9A CB9A 369.78 369.244 0.54 CB9 CB9 370.08 369.242 0.84 C810 CB10 370.57 370.303 0.27 CB10A C810A 370.54 370.54 0 CB11 CB11 370.85 370.689 0.16 CB11A CB11A 370.78 370.69 0.09 CB11B CB118 370.9 370.751 0.15 CB12 CB12 371.3 371.084 0.22 CB13 CB13 371.97 371.42 0.55 CB14A CB14A 371.59 371.59 0 CB14 CB14 372.3 371.691 0.61 CB15 CB15 372.37 371.914 0.46 C815A CB15A 371.61 371.61 0 C814C CB14C 373.43 371.615 1.81 CB15C CB15C 376.36 373.17 3.19 CB150 CB150 382.03 379.23 2.8 C816 CB16 374.35 373.612 0.74 CB17 CB17 378.16 376.102 2.06 CB18 CB18 378.63 377.195 1.44 CB18A CB18A 378.66 377.601 1.06 CB19 CB19 379.29 377.209 2.08 C820 C820 379.8 377.226 2.57 CB21 CB21 380.47 377.315 3.16 CB4A C84A 373.58 368.27 5.31 C8148 CB14B 372.27 371.598 0.67 CB158 CB158 374.02 371.611 2.41 OS OS 340 337 3 CB15A-1 CB15A-1 372.33 372.33 0 C848 CB4B 371.36 370.179 1.18 CB4C C84C 370.43 370.43 0 N15A-2 N15A-2 378 377.519 0.48 Table C.4. XP-Storm 25-Year Flow Rates Max Max Velocity Invert Water Max Flow (!tis, mis) Node Elevation Elevation Link Name cfs ft/s Name fl ft P01 10.86 10.01 CB1 355.41 356.17 P02 10.86 3.99 CB2 359.42 361.10 P04 10.87 3.91 CB3 361.55 363.22 P06 10.90 4.12 CB4 363.83 365.39 P10 4.89 1.78 CBS 363.88 365.55 P12 4.90 1.84 CB6 364.11 365.71 P14 4.63 2.62 C87 364.93 366.83 P16 4.63 2.60 CBS 365.45 368.10 P19 0.30 0.38 CB9A 366.73 369.24 P18 4.42 2.49 CB9 365.93 369.24 P20 4. 13 2.31 CB10 366.45 370.30 P21 1.33 1.67 CB10A 367.11 370.54 P22 2.80 1.57 CB11 366.95 370.69 P70 0.12 0.15 CB11A 367.56 370.69 MU11A 2.66 1.33 CB11A 367.56 370.69 MU11B 1.96 0.82 CB118 369.40 370.75 MU11B 0.80 0.58 CB11B 369.40 370.75 P24 2.57 1.44 CB12 367.52 371.08 P26 2.57 1.44 CB13 367.85 371.42 PSO (1.19) (1.50) CB14A 389.46 371.59 ST14A 2.76 1.57 CB14A 369.46 371.59 P28 2.57 1.44 C814 368.15 371.69 P30 3.56 2.00 CB15 368.42 371.91 P60 (2.07) (2.60) CB15A 369.19 371.61 OV15A 1.40 0.78 CB15A 369.19 371.61 P54 0.39 0.49 CB14C 370.25 371.62 P32 5.04 2.82 CB16 369.15 373.61 P34 5.04 2.82 CB17 371.76 376. 10 P36 5.04 2.82 CB18 372.93 377.20 P37 5.13 2.88 CB18A 373.91 377.60 D1 14.66 3.09 CB18A 373.91 377.60 P38 (0.37) 0.20 CB19 374.69 377.21 P40 (0.32) 0.26 CB20 374.72 377.23 P42 0.16 0.87 CB21 375.98 377.32 P08 5.73 3.35 CB4A 366.18 368.27 P52 0.39 0.49 CB14B 369.89 371.60 P61 3.78 4.78 CB15A·1 370.20 372.33 P61 2.55 5.62 CB15A-1 370.20 372.33 P08A 5.73 3.22 CB4B 367.26 370.18 P08B 5.73 3.23 CB4C 367.63 370.43 D2 14.66 8.62 N15A-2 375.00 377.52 infiltrates at this location outside the road right-of-way or continues to flow to the Carolwood infiltration pond. Flows larger than approximately 10 to 15 cubic feet per second likely do not reach beyond CB 5 (located at the intersection of 160th Avenue SE and SE 144 1 h Street), within either the pipe or roadway. 2-10 SE I 44"' Street-June 2()()7 3. DRAINAGE MITIGATION OPTIONS The following four concepts were developed to mitigate for the proposed developments' impacts of downstream flooding: • Providing onsite detention to King County Level 3 flow control standards • Providing offsite conveyance system upgrades (Offsite Option 1) • Providing offsite conveyance system upgrades and infiltration (Offsite Option 2) • Providing offsite conveyance system upgrades and infiltration by implementing bioretention (Offsite Option 3) 3.1 Onsite Level 3 Detention Level 2 stormwater detention standards are required for the Threadgill, Liberty Gardens, and Cavella developments. When downstream severe roadway flooding is of concern, Level 3 stormwater detention standards are often included in the drainage design for new development as a stormwater mitigation. Providing this type of mitigation has been used with success on several projects in King County. Level 3 detention standards would likely adequately mitigate the impacts of flooding from the proposed projects on downstream flooding. Adequately mitigating the flooding problem, at minimum, requires that runoff from the projects not aggravate the existing level or duration of flooding nor create new flooding. Adopting this strategy as a mitigation has several advantages that appeal to developers. Because the mitigation is entirely onsite, the developer has control of its design and implementation. No easements, consents, or coordination with downstream property owners is required. The mitigation is typically easy to implement because it is simply a matter of enlarging the already proposed Level 2 stormwater facility. This type of mitigation particularly makes sense where the proposed development is small relative to the surrounding basin and the required downstream upgrades are either logistically difficult or overly expensive to implement. The main disadvantage to providing Level 3 detention as a flooding mitigation is that while existing problems are typically not aggravated, the problems are not solved either. 3.2 Offsite Conveyance Improvements Offsite mitigation Option I would include improving the conveyance system along the north side of SE 144th Street (Figure 6). Between 162°d Avenue SE and 160th Avenue SE this would entail upsizing driveway culverts and re-grading and cleaning open sections of the existing roadside ditch. From 1601 h Avenue SE to 156th Avenue SE, a distance of about 1,300 feet, an 18-inch diameter storm pipe would be constructed to increase conveyance capacity. 3-1 SE 14!" Street-June 2007 i i i ' I ' ·-·-·~t -·1--- 1 ' T ___ l_ --- i i I ·j ·· ~ I ;!I " f-' .. ::ii l' ... "" -· •• i ' I l-- i ...... ·····---·-_i, __ _ ' ! r~; -' ~! ;!~fl ~ i .. ~_-:-. :'! .:0 l :!!~ 8 \ 8!0 l !?5! 8 if 1 ~ • ii i i i i i i i ~-r---,~:.1 ,.-' '" • i. -·---·- ~' • • •• I = .. = .... I I -;·-- ~ ! : u I ..!:l i = = .. i:.. " = = .. .. "Cl ~ ~ u I:: = Cl) r..: Appendix D. HEC-RAS Analysis of Roadway Conveyance Description of inputs: Geometry: Geometry of roadway based on Barghausen Consulting Engineers field survey from 6/07. STA Descriotion 0+00 10' west of CB-11A 1+60 10'west of CB-118 6+60 160' east of CB-15A-1 8+10 290' west of CB-1 BA 1010 85' west of CB-18A Flow: Based on cumulative 100-year peak flow rate to the conveyance system predicted by KCRTS 1- hour time series minus the estimated capacity of the 18-inch pipe on the south side of SE 144'" Street (5.0 cfs). SE 141" Street-June 2007 SE 144th Roadway Conveyance Plan: SE144th Roadway 6/17/2007 Geom: SE144th Flow: Roadway a 144th 1 -, 380 Lege~_cl WS Exis Ground --------I ROB I 378 376 g C 0 1 w 374 372 0 0 + <O 'f + + 0 -"' "' -.!!I &] &] .!!I "' "' 370 ' 0 200 400 600 800 1000 1200 Main Channel Distance (ft) SE 144th Roadway Conveyance Plan: SE144th Roadway 6/17/2007 Geom: SE144th Flow: Roadway a River~ 1441h Reect> ~ 1 RS~ 1010 Sta 10+10 :~ o,---035--------,j ws ... / ~ • g Bank Sta i "' "' "' ,n 376 -30 -20 -10 0 10 20 --·--------;io S!atloo till SE 144th Roadway Conveyance Plan: SE144th Roadway 6117/2007 Geom: SE:1«Ui Row: Raedwa)' a River = 144U, Reach = 1 RS= 810 Ste B+10 378,1 ' -= " .006 '"'l I WS&. 3n.o ,------o,;;;;;;- g seJste I 37B.5· 376.D 375.5 375.0 37-4.5 -30 -20 ·ID 0 10 20 30 40 50 Stillion (ft.) SE 144th Roactway Conveyance Plan: SE144th Roadway 6117/2007 Geom: SE144th Flow: R<>ad-.ny Q River• 144th Reech• 1 RS •"" Sta S->60 -= " .035 375. Lagind ,,._ ~ WSE,ds 37<1.5 Ground • £3H Bank Sle § 373.5 i 373.D 372.5 372.0 371.5 -~ ·30 .,o ·10 0 ID " 30 " '" St.allan (ll) SE 144th Roadway Conveyance Piao: SE144th Roadway 6/17/2007 Geom: SE1-441h Flow. Raadway a Riller• 144th Reach" 1 RS" 160 SIii 1~so f,-022 ·" "' m~ 374.0 ~ WSExia 373.5 ~ • € 373. Sank Sta I 372.5 372.0-1 371.5 371.0 370.5 _,,, -20 -10 0 10 20 30 " so Station (ft) SE 144th Roadway Conveyance Plan: SE144th Roadway 6/17/2007 Geom: SE144th Flow. Roadway Q Rlwir = 144th Reach= 1 RS" O StaO+OO ·= ·" .022 ::::1 "'""" ws Exill 371.fi .=-• i '"' Bank Sta 370.5 370.0 369.5 369.0 ~--~--· ... .., ~, 0 20 ., " station {ft) -- HEC-RAS Plan: SE144th River: 144th Reach: 1 Profile: Exis Reach River Sta Profile a Total Min Ch El W.S. Elev CritW.S. E.G. Elev -- E.G. Slope I Vel Chnl Flow Area Top Width Froude # Chi (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) --1 1010 Exis 20.09 378.07 378.44 378.22 378.56 0.005394 2.69 7.44 20.08 1.35 1 810 Exls 20.09 376.47. 376.22 376.22 376.57 0.023460 4.23i 6.22 0.00 ~-. 1 660 Exis 20.09 373.69 373.70 373.33 373.84 0.006877 0.31 6.62[ 7.79 0.86 ---~ 1 160 Exis 22.42 370.90 371.63 371.63 371.77 0.002867 3.25 7.92 28.69 1.12 1 0 Exis 22.42 370.70 371.16 371.14 -~ 371.27 D.003401 3.00 9.76, 44.46 1.17 Ed 1VlcCarU1y. P.E., P.S. 995! l 7-J',1 ,,,,,enuc SE Renton, \A/,6.. SJSU:39 :'el r4:2~::, 2J .. l-57J,t P.O. BOX 1255 F\LE cog}sEY ENGINEERING FALL CITY, WA 98024-1255 CELL: 206-227-8187 FAX:425-228-7232 November 20, 2003 Bruce Whittaker, P.E. L.U.S.D. King County D.D.E.S. REFERENCE: Liberty Grove Contiguous, L03P0005, (L03TY40I) and Liberty Grove, L03P0006, (L03TY403) SUBJECT: Response to November 12, 2004, Plat Screening, Request For Additional Downstream Information Dear Mr. Whittaker: The following is a narrative of the existing downstream system from the Parcel "B" portion of the Liberty site to the Petrie Property. A. Description of stormwater drainage within the Parcel "B" portion of project: The stormwater generated from the site in the existing condition and any stormwater that enters the site from the north (SE 136th St.) flows to an existing wetland at the southern central portion of the property. The wetland is shown on the preliminary plat. Stormwater leaves Parcel "B" at the low point of the wetland and flows to the south. It should be noted that the wetland is not a closed depression. B. Description of Storm water Drainage Across Property#!: Tax Parcel#: "0095" 13802 160th Ave. SE Steve & Joanne Lee This property is located directly to the south of Parcel "B" of the proposed development. Permission was granted by the property owner to cross this property. Stormwater leaving Parcel "B" (under a wood fence) enters Property#! and is intercepted by a constructed swale (sump). See Picture#2 that is taken from the STORMWATER HYDRAUUC ANALYSIS CIVIL ENGINEERING DESIGN RECEIVED MAIN FILE COPY NOV 2 5 2003 KING COUNTY Af~//1/,:,. LAND USE SERVICES 'l.~cop" LAND PLANNING North end of the swale looking south. The swale (sump) is approximately 15' wide and 28' long. At the south end of the swale there is a 12" Concrete Pipe (CP). The top of the existing grade around the swale is approximately 3.5' above the IE of the culvert. The culvert conveys stormwater across this property to the adjacent property to the south. Within this property there is also an additional swale that flows into the above mentioned sump. The swale is to the south of the Parcel "B" fence and begins approximately 50' east of the southeast corner Parcel "B". This swale intercepts stormwater leaving the Parcel "B" property and directs the stormwater to the west to the sump feature. Picture #1 is taken to the east of the sump, looking to the east. This swale is approximately 10' wide and 2' deep with gentle side slopes. The swale is grassed and is stable. C. Description of Stormwater Drainage Across Property#2: Tax Parcel#: "0096": 13814 160th Ave. SE Brett Bowden. Mr. Bowden granted permission to cross his property. Reach 1: A 12" CP conveyance system outfalls from Property 1 to Property 2 adjacent to a large cottonwood stump. The pipe discharges into a short swale/ditch that is approximately 8' long and 3' wide. The swale is approximately 3' deep with varying side slopes and appears to be stable. At the end of the swale is a 12" CP pipe that conveys stormwater under a gravel road. The IE of the CP to the top pf the gravel road is approximately 2.5'. Reach 2: Stormwater leaves the 12" CP under the gravel road and enters a broad swale. Picture#3 was taken near the upstream culvert under the gravel road looking to the south. The swale is approximately 110' long, 3' wide at the bottom, approximately 3' deep with varying side slopes. The swale ends at another gravel road. There is a 12" CP at the southern end of the swale where the water is conveyed under the gravel road. Picture #4 was taken at the southern end of Reach 2 looking to the north. D. Description of Stormwater Drainage Across Propertv#3: Tax Parcel# "0101": The property owner was not home and a card was left at the front door. Reach 1: Stormwater leaving the 12" CP under the gravel road from Property 2, discharges into a shallow ditch on the north side of the driveway access to the Property 3 residence -see Picture #5. The ditch flows for a short distance to the south and then turns to the west -see Picture #6. At the western terminus of the ditch, stormwater is intercepted by a 12" CP that conveys stormwater under the driveway to the south. Picture #7 shows the outfall at the southern side of the gravel drive. The ditch is approximately 2' wide, 1' deep with varying side slopes. There was approximately 2' from invert to the top of the gravel road. There were no observed capacity issues within this reach. , z :;,,;/, i,:;,o' "I' . r.o. Box 12ss FILE COP'/ FALL CITY. WA98024-1255 CELL: 206-227-8187 FAX: 425-228-7232 CASEY ENGINEERINcf·CEiVED , November 20, 2003 Karen Scharer, Planner L.U.S.D. NOV 2 5 2003 KING COUNTY LAND USE SERVICES 10 a vooo5 King County D.D.E.S. REFERENCE: SUBJECT: Dear Ms. Scharer: Liberty Grove Contiguous, L03P0005, (L03TY401) and Liberty Grove, L03P0006, (L03TY403) Response to November 12, 2004, Plat Screening, Request For Additional Information On behalf ofLakeridge Development, Inc.,the following is a response to the November 12, 2003 letter. 1. Property Description. Engineering & Surveying: Attached are three copies ofan attached "Waste Disposal Drain Field Easement" that is the only known easement that has not been disclosed at this time. This easement will be relinquished at the time the project is recorded. 2. Drainage: Attached to this letter are 10 copies of the requested additional downstream information. It is proposed that the combined water quality facility within the project be designed to provide for hydrology to the existing on-site wetland and the existing downstream system. 3. Rezone{s): The Applicant respectfully requests that the rezone application be withdrawn. This request for the withdrawal of the rezone application was made clear in the August 6, 2003 letter from Lakeridge Development to Karen Sharer. Attached is a copy of the letter that has been already submitted to King County D.D.E.S. STORMWATER HYDRAULIC ANALYSIS CIVIL ENGINEERING DESIGN LAND PLANNING Karen Scharer November 20, 2003 Page 2. Lakeridge Development, Inc. greatly desires to schedule a hearing date at your earliest convince. Thank-you for your consideration. If you have any questions, please feel free to contact me at any time. Sincerely; 5.P o-wl 1t/. 7 David W. Casey, P.E. Casey Engineering Attachments: I. 3-Copies of "Waste Disposal Drainfield Easement" Document. 2. I-Copy of"Plat Screening Transmittal" Document. 3. I-Copy of August 6, 2003 Letter From Lakeridge Development, Inc. to Karen Scharer -previously submitted. 4. IO-Copies of Requested Additional Downstream Information. Cc: Bruce Whittaker, P.E., King County LUSD,DDES ® Plat Screening Transmittal King County Preliminary Plat App's: Liberty Grove Contiguous, and Liberty Grove Deparnnent of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwesc Remon, Washington 980:5.5·1219 LUSD File No. L03P0005 (L03TY401), L03P0006(L03TY403) Date of Information Request: November 12, 2003 Deadline for Submittal of Information: February 12, 2004 1. Property Description, Engineering & Surveying: a. The title report discloses several easements affecting the property. Many of these were not included with the title report and need to be reviewed prior to preliminary approval. Some may need to be relinquished. Submit easement documents for LGC so that review of their impacts may be completed. 2. Drainage: Please respond to comment 4b of the previous screening letter dated June 3, 2003 which states:. b. Revise the Level 1 Off Site Analysis to include evaluation of the existing downstream drainage course from the Liberty Grove Contiguous site. It appears that the existing drainage course flows to the east of known capacity problems on Lot 6, Block 3 of Cedar Park Five-Acre Tracts (downstream points 30 and 31 in the Analysis). Please show appropriate mitigation for routing the post developed drainage through this area per Core Requirement 2 of the KCSWDM. Note that the Level 1 Analysis can be extended more than Y. mile if a problem is anticipated (1.2.2.1 KCSWDM}. It is anticipated that up sizing the existing culverts east of 160the Ave. SE will be required. A letter of positive intent from the property owner(s) is required for any proposed improvements off the R/W. A full description and Level 1 Analysis of the existing drainage course is required. The existing drainage course should be evaluated so that all options for the proposed surface water adjustment can be fully explored. It is still anticipated that up-sizing the existing culverts across Lot 6, Block 3 of Cedar Park Five-Acre Tracts will be required. Please note that the applicant for the proposed Nichols Place L03P0015 subdivision is also evaluating the feasibility of up-sizing the culverts. We suggest that coordinating this effort may be beneficial to both applicants. Please contact Bruce Whittaker at 206-296- 7211 ·for further information The proposed surface water adjustment has been placed on hold pending receipt of the above information. Please contact Mark Bergam at 206-296-7270 for more information on the proposed adustment. Please provide ten (10) copies. L03P0005 & L03P0006 2"' Plat Screening Transmittal 11/12/03 Page 2 3. Rezone(s): Please clarify whether you wish to withdraw applications for reclassification or if you wish to continue processing the rezone requests. 2 L03P0005 & L03P0006 Plat Screening Transmittal Page 3 e. Perform a travel time analysis to compare an actual morning peak hour travel time along the 160'h Avenue to SE 144'" Street to SE 156'" Street trip versus a theoretical SE 136'" Street to 156'" Avenue SE, with appropriate delays factored into the westbound left turn to proceed southbound on 156'" Avenue SE. The newly constructed west leg of SE 1361h Avenue SE may serve as a reasonably accurate source of data on the delays required to complete a left turn across 156'" Avenue SE. Other single lane approach "STOP" controlled intersections along the portion of 1561" Avenue SE, between SE 128th and SE 142"" Place. f. Updated traffic accident history (that is, include 2002). For more detailed information regarding the traffic study, please contact Kris Langley, Senior Engineer, Traffic & Engineering, KCDOT at (206) 263-6102 or (206) 296-7155 (or kristen.lanqley@metrokc.gov. Please provide ten (10) copies. 6. Road Variances: a. Please submit variances to the KCRS as necessary. b. Intersection spacing: plat entrance (LG) at 160'" Avenue SE (measured relative to the intersection of SE 135'"!160'" Avenue SE) does not appear to meet King County Road Standards for a Neighborhood Collector street. 7. Road Improvements: a. Please provide a conceptual frontage improvement plan for LGC that includes (under a rezone scenario) an improvement of the frontage of the three intervening parcels (0086, 0087, 0088) that appear to have been segregated via a plat KING CO ENGINEER SUBDIVISION NO 6846 REC NO 9410250673 from the Tax Lot 0085 (the northerly portion of LGC). b. Please provide a conceptual frontage improvement plan for LG that includes the referenced improvements to SE 136th Street to complete the improvements that are required of the Applicant of the Evendell subdivision (DOES File L01 P0016) under both the proposed (and subsequently denied) rezone configuration and the approved 46-lot (current zoning). c. If the Applicant for {he plat of Evendell does not succeed in the re.quested appeal to the County Council, the off-site connection of SE 136'h Street will not be constructed. This requirement may be placed upon this application as potential mitigation of plats' impacts at the intersection of SE 128th Street/ 160'" Avenue SE. Please provide a conceptual plan for the improvement of SE 136'" Street between 158th Avenue SE and 1561h Avenue SE, including a sidewalk on (at least) the north side of the roadway, and a conceptual plan for the re- channelization of 156'" Avenue SE at SE 136'" Street. 8. Pedestrian Connectivity/School Walkways: a. Information has been provided in the past that school age pedestrians have a gate available for access to the west side of the Liberty High School. Identify the walking routes from both LGC and LG to the location of the gate. Identify the conditions along the route. Where abutting the boundary of the LGC and LG plats, and, if not otherwise required, provide frontage and off-frontage improvements to accommodate this pedestrian activity . ., L03P0005 & L03P0006 Pia~ Screening Transmittal Page 4 b. Provide an analysis of walkway access to schools serving the two plats of Liberty Grove & Liberty Grove Contiguous (Liberty High School, Maywood Middle School, and Briarwood Elementary). See the attached comments from the Issaquah School District. 9. Wetland/Stream: A site visit was made to verify the wetland areas on Friday May 30, 2003. Based on this field visit the following additional information in regards to wetlands. There is an off-site wetland located north of SE 136'" Street and east of 162"a SE. Flows from this wetland enter the site in the northeast corner of the property and flow south along the eastern edge of the site, in the area of proposed lots 9 -16. It appears that the water ponds in the area of proposed lots 17 -20. The applicant's biologist should evaluate these areas for wetlands. The submitted wetland report does not address these areas of concern. 10. Revised Preliminary Plat(s): Provide 15 copies of each revised preliminary plat, as necessary, as a result of above-referenced requests for additional information and 4 copies of any special study requested for each plat unless otherwise noted. As a result of the review of the information, additional information (studies, revisions, etc.) may be requested at a later date. Further evaluation of these issues may result in the reconfiguration and/or loss of lots. 11. Rezone(s): Based on the information submitted, ODES staff finds insufficient justification to recommend reclassification of either rezone request, see Comprehensive Plan Policy U-122. You may choose to submit further information, which addresses this policy as it applies to each site. Please provide two copies for each rezone file. 4 REVISED 09/03103 Purpose of Checklist: The State Environmental Policy Act (SEPA), chapter 43.21 C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help King County and I or any other agencies with jurisdiction to identify impacts from a proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help King County decide whether an EIS is required. A. BACKGROUND 1. Name of pre posed project, if applicable: Liberty Grove Contiguous Subdivision 2. Name of proponent: REVISIO Lakeridge Development, Inc. 3. Address and phone number of proponent and contact person: Proponent: Contact Person: 4. Date checklist prepared: February 28, 2003 Lakeridge Development, Inc. PO BOX.146 Renton, WA 98057 (425) 228-9750 Phone Mel Daley or Hans Korve DMP Engineering 726 Auburn Way North (253) 333-2200 Phone (253) 333-2206 Fax REVISED 09/03/03 5. Agency requesting checklist: King County, DOES 6. Proposed timing or schedule (including phasing, if applicable): Application Submittal ............................ March 2003 Public Hearing ........................................ December 2003 Council Action ........................................ February 2004 Engineering Submittal .......................... April 2004 Site Grading ........................................... May 2004 Final Plat ................................................. December 2004 10SP00o5 RECEIVE. SEP O 3 2003 f111~li COUNTY LAND USE SERVIC S FOR AGENCY USE ONLY 1 LGC HAIN FILE COPY REVISED 09/03/03 7. Do you have any plans for future additions, expansions, or further activity related to or connected with this proposal? If yes please explain. No. 8. List any information you know about that has been prepared, or will be prepared, directly related to this proposal. The following information will be prepared and submitted under separate cover or is available in County files: • Rezone application • DDES • Level 1 Downstream Analysis REVISED July 11 1 2003 • Conceptual Drainage Plan • Traffic Study, DN Traffic Consultants, February 7, 2003 • Wetland Report -Habitat Technologies, November 5, 2002 • Preliminary Recreation Plan • Traffic Study, DN Traffic Consultants, REVISED July 24. 2003 • Drainage Adjustment Reguest, July 11, 2003 • School Walking Route Analysis, August 18, 2003 • Addendum Wetland Report. H&S Consulting. July 18, 2003 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by this proposal? • Applicant has submitted a rezone application with this subdivision application. • Evendell Preliminary Plat approval (L01TY401) • Liberty Grove Preliminary Plat Approval 10. List any governmental approvals or permits that will be needed for your proposal, if known. SEPA Threshold Determination Re-zone Approval Preliminary and Final Plat Approval Clearing and Grading Permits Building Permits King County King County King County King County King County 11. Give brief, complete description of the proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. SUBDIVISION The proposed preliminary plat will subdivide two parcels, totaling 7.92 acres located on tax parcel(s) 145750 -0085 and 145750 · 0090 into 36 single-family lots, open space, and access tracts. The property is located on the east side of 160"' Ave. SE (145750-0085 & 0090) and contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home and all the associated outbuildings are proposed for removal. This property is the second half of the original "Liberty Grove" project. All storm water, traffic and recreatipnal issues have been reviewed as one project but will be presented with each individual segment. 2 FOR AGENCY USE ONLY LGC REVISED 09/03/03 The associated re-zone application has been rejected by Staff and the applicant has submitted a TOR proposal to maintain the proposed density. Sewer service to the proposed project site will require extension of a 10" to 12" off-site sewer line from approximately 154ffi Ave. SE to 162"' Ave. SE. within the existing SE 136ffi Street right-Of-way. Additional improvements may include a 10" sewer main in 162"' St. SE, and a 8" sewer main in 158ffi & 160'" Ave. SE REZONE This project and its contiguous neighbor, Liberty Grove have applied for a rezone from R-4 to R-6. This proposed rezone would be consistent with the current comprehensive plan designation. This proposal will also be consistent with the development patterns of the surrounding area. The plat of Evendell located west of the Liberty proposal is currently being rezones from R-4 to R-6 as well. Since the original application, Staff has withdrawn their support of the re-zone application. In response, the applicant has submitted documentation to utilize the Counties TOR program to attain the proposed lot density. No additional impacts will result fonn the use of the TOR program. 12. Location of the proposal. Provide a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if available. The subject proposal is situated on three parcels totaling 7.92 acres, located within the jurisdictional boundaries of unincorporated King County in the SEY, of Section 14 Township 23 North, Range 5 East W.M. The site is located on parcel(s) 145750-0085 and -0090. Please refer to the Preliminary Plat map for the legal description, site plan, vicinity map, and topographic map. The proposed Plat of Liberty Grove is located to the north on the west side of 160111 Ave. SE. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one):! flat I. kollinal, hilly, steep slopes, mountainous. The project site is located on the east side of 160111 Ave. SE. (-0085 & -0090) and contains a few minor slopes in the northeast comer of the property and a non-jurisdictional drainage channel which extends through the center of the property, from north to south. The northeastern portion of the site is classified as forested uplands. The remainder of the property is pasture with two existing homes and out buildings. One Class 3 wetland has been identified in the south-central portion of the site. The finding and classification has been reviewed and approved by ODES staff. Please refer to the preliminary plat map for detailed contour infonnation. b. What is the steepest slope on the site (approximate percent slope)? According to the field topographic survey, the steepest slope on the site is approximately 5% to 10% located northeast comer of the project site. 3 FOR AGENCY USE ONLY LGC REVISED 09/03103 c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, and muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. According to the US Soil Conservation Service Soil Map, the site is primarily Alderwood series {AgC) d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. According to the King County Sensitive Areas Map, the property contains no hazard areas. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. Grading of the site will be necessary to modify the site for stormwater drainage flow. The exact quantity of grading is not known at this time, however, it is anticipated that the grading activities would be designed to· balance and not require import or export of soil. Grading of the individual home sites will involve the excavation of approximately 150 to 200 CY of cut and/or fill. These issues will be addressed during the building permit phase. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Some erosion could occur on-site as a result of construction activities; however, temporary erosion and sedimentation control measures to be approved by King County will be employed to reduce erosion impacts. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Due to the preliminary nature of the plans, the exact percentage of impervious surface associated with this project is currently unknown. The subject proposal will not exceed the maximum impervious surface area as required by KCC 21 A.12.030 h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, the contractor will follow an approved temporary erosion and sedimentation control plan meeting KCC standards. Typical measures, which may be employed, include the use of silt fences, straw bales, and temporary storm drainage features. Hydro seeding exposed soils and cleared areas after construction will also reduce the potential for erosion. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. 4 FOR AGENCY USE ONLY LGC . ,_..:.-::: _;;-:,e;-:·; ,_; 0'.1 e '.~::,n:1Q~:, ,1s ?n~i,n1;1:crv ,-,i~1· REVISED 09/03/03 2. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, and industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Construction: Emissions and dust particulates generated primarily by construction equipment will be produced during the construction phase of this project. The amount of emissions to the air will be minimal and will occur during the actual construction of the development. Long Term Air Quality: Long-term air impacts would be those typically associated with residential land uses. Sources of long-term emissions and odor could include vehicle emissions from increased vehicle use generated by the new residential units and emissions from wood burning fireplaces (if pennitted). The additional vehicular emissions in these areas are not anticipated to concentrate and therefore are not anticipated to create a health hazard to the residents or surrounding areas. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No. c. Proposed measures to reduce or control emissions or other impacts to air, if any: If particulates become suspended during construction, frequent watering of the site during the construction phase of the project would be used to help control dust and other particulates generated on the site. This will be accomplished in accord with Section 5.4.7 of the 1998 Surface Water Design Manual. 3. Water a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. According to the King County Sensitive Areas 'Folio, there are no recorded streams or other water bodies on the subject site. However, field investigation has revealed the presents of a single Class 3 wetland feature in the south-central section of the site. Habitat Technologies has 5 FOR AGENCY USE ONLY LGC REVISED 09/03/03 completed a full wetland assessment and report. The report was reviewed and approved by DOES Staff on November 27, 2002. 2) Will the project require any work over, in or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. The Class 3 Wetland, identified in the wetland report will be preserved and accorded the appropriate 25' buffers and 15' building setback. Grading and other construction activities are expected within 200' of the wetland feature but outside the required buffers. Appropriate measures will be taken to insure the integrity of the wetland feature during construction. Refer to the attached wetland report for complete details. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Creation of the proposed single-family lots will not require the adverse impact or placement of fill within identified wetland areas or buffers. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan According to the King County Sensitive Areas Maps, no portion of the site lies within the 100-foot flood plain. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No. b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. None known at this time. c. Water Runoff (including storm water): 6 FOR AGENCY USE ONLY LGC ' :,1 _....:.7:) 1_·r::<:::-:y .:;:u:e r~ :;nt·:/.IOUS :-=-rei·:rn,t'.a:-y =-:c;r REVISED 09/03/03 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water fiow? Will this water flow into other waters? If so, describe. On-site storm water runoff will primarily be generated from roadways, residential structures, and associated driveways. Storm water will be collected in catch basins within the roadways and/or tight-lined from residential roof tops and conveyed to a proposed detention facility located on the project site (southwest corner of -0090). Storm water from the proposed plat of "Liberty Grove" will be transferred along 160"' Ave. SE and processed in the single storrnwater facility located on parcel -0090. Discharge from the proposed facility will be piped into the existing storm water system. Refer to the attached Level 1 storm water report for complete details. 2) Could waste materials enter ground or surface waters? If so, generally describe. Some pollutants normally associated with residential development could enter the surface water; however, the amount would be minimal since the on-site drainage will be conveyed to a water quality and detention facility in conformance with the 1998 Surface Water Design Manual. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: The storm water runoff will be collected and conveyed to a detention facility(s) that will be designed and constructed in conformance with the 1998 Surface Water Design Manual. 4. Plants a. Check or circle types of vegetation found on the site: deciduous tree: alder, maple, aspen, other: evergreen tree: fir, cedar, hemlock, pine, other shrubs grass pasture crop or grain wet soil plants: cattail, buttercup, bullrush, skunk cabbage water plants: water lily, eelgrass, milfoil, other: b. What kind and amount of vegetation will be removed or altered? The north portion of the project site, on the east side of 160"' Ave. SE, is currently covered with evergreen and deciduous trees with the remainder of the property in grasses and pasture land. There is some ornamental vegetation associated with the existing homes. The majority of existing vegetation will be removed during the grading process with the exception of buffer vegetation surrounding the retained wetland feature. All ornamental landscaping associated with the homes to be demolished will also be removed. See the attached wetland report for a complete list of existing vegetation. c. List threatened or endangered species known to be on or near the site. 7 FOR AGENCY USE ONLY LGC REVISED 09/03/03 There are no known threatened or endangered plant species on or near the site. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: The proposed preliminary plat anticipates retaining existing trees when possible. The new single-family residences will provide new landscaping including lawns, shrubs, and ornamental trees. Native vegetation will be utilized, where appropriate. Some additional trees and vegetation may be incorporated into the recreation area and storm water facility where appropriate. 5. Animals a. Circle any birds and animals, which have been observed on or near the site or are known to be on or near the site: birds: hawk, heron, eagle, songbirds, other. mammals: deer, bear, elk, beaver, other: rodents. raccoons. fish: bass, perch, salmon, trout, herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. None Known. c. Is the site part of a migration route? If so, explain. No. d. Proposed measures to preserve or enhance wildlife, if any: Retain native vegetation within the sensitive areas tract associated with the retained wetland feature. In addition, installation of native landscaping throughout the plat area will provide coverage and habitat for urban tolerant wildlife. Typical landscaping is likely to include rhododendron, azalea, boxwood, magnolia, cedar, hemlock, blue spruce, cherry, plum, maple and ash. Some additional landscaping will be installed in association with the proposed recreation facility. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electrical energy will be the primary source of power serving the needs of the project and natural gas will be made available for the purpose of heating and other needs associated with residential living. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No. 8 FOR AGENCY USE ONLY LGC REVISED 09103/03 c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: The residential buildings that will be constructed as a result of this project will meet or exceed the applicable single-family residential energy conservation / consumption requirements in King County and the Uniform Building Codes. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. It is unlikely under normal working conditions that environmental health hazards would be encountered. All project-related construction will meet or exceed current, County, State and Federal laws. 1) Describe special emergency services that might be required. In the event that environmental health hazards are encountered or occur during construction, all appropriate precautionary measures will be employed. Any emergency situation would be addressed by the existing resources of Fire District #25. 2) Proposed measures to reduce or control environmental health hazards, if any: State regulations regarding safety and the handling of hazardous materials will be followed during the construction process. Equipment refueling areas would be located in areas where a spill could be quickly contained and where the risk of hazardous materials entering surface water is minimized. On-site management will be equipped with mobile communications equipment at all times to contact emergency services in the event of an incident. b. Noise 1) What types of noise exist in the area, which may affect your project (for example: traffic, equipment operation, other)? The dominant source of noise in the project vicinity is traffic along 160"' Ave. SE, which bisects the proposed project, 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Short-term impacts would result from the use of construction equipment during site development. Construction would occur during permitted construction hours and in compliance with King County noise standards. 9 FOR AGENCY USE ONLY LGC REVISED 09103/03 3) Proposed measures to reduce or control noise impacts, if any: Construction activity will be limited to pennitted construction hours and construction equipment will not be allowed to idle for continuous periods of time, which will help to mitigate the impacts of potential construction noise. Hours of operation will be posted on-site. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site(s) are currently used as single family residences. One of the existing properties contains a barn and other outbuildings associated with the keeping of live stalk. Adjacent land uses consist of a low density single- family residence. The existing plat of Liberty Lane is located to the east and the proposed plat of Evendell is located to the west. b. Has the site been used for agriculture? If so, describe. It is not believed that the site was utilized for agricultural production in the past. c. Describe any structures on the site. The property on the east side of 160"' Ave. SE , "Liberty Grove Contiguous" (145750-0085 & -0090) contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home on lot -0085 and all the associated outbuildings are proposed for removal. • 1,240 SF home located at13612160TH AV SE 98055 (145750-0085) • 2,410 SF home located at 13644160TH AV SE 98055 (145750-0090) d. Will any structures be demolished? If so, what? Yes. One of the homes and all of the out buildings are proposed for removal. e. What is the current zoning classification of the site? The project site is currently zoned R-4. The applicant has submitted a proposal to rezone the property as R-6 or utilize the Counties TOR program to achieve the desired lot count. f. What is the current comprehensive plan designation of the site? According to the King County Comprehensive Land Use Plan, the area is designated Urban Residential -R 4-12. This designation would support the proposed rezone of the property. g. If applicable, what is the current shoreline master program designation of the site? 10 FOR AGENCY USE ONLY LGC REVISED 09/03/0J Not applicable. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. According to the 1990 King County Sensitive Areas Folio no part of the property has been designated as sensitive. However, field investigation has identified a low value, minor Class 3 wetland feature on-site. The feature is located in the south~entral segment of the project site. See attached Wetland Report. An addendum wetland study has been provided in response to Staff comments. i. Approximately how many people would reside or work in the completed project? Assuming 2.5 persons per household, approximately 90 people would reside in the proposed project. j. Approximately how many people would the completed project displace? 2.5 k. Proposed measures to avoid or reduce displacement impacts, if any: The proposed project will provide 35 !!fil! housing units, 36 total. I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The project will be developed in accordance with applicable King County development and land use codes to ensure the project is consistent with the goals and policies of the Comprehensive Plan and applicable development regulations in effect at the time ofa complete Preliminary Subdivision application. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Approximately 35 (36 total) !!fill! middle-income housing units will be provided. b. Approximately how many units, if any would be eliminated? Indicate whether high, middle, or low-income housing. Two middle income homes will be removed. c. Proposed measures to reduce or control housing impacts, if any: Adherence to the comprehensive plan and growth management planning goals of King County would ensure that housing development is consistent with those policies stated in the applicable land use plan. 35 new homes will be built. 11 FOR AGENCY USE ONLY LGC REVISED 09/03/03 10. Aesthetics a. What is the tallest height of any proposed structure(s). not including antennas; what is the principal exterior building material(s) proposed? No specific building plans are included with this project; however, it is anticipated that houses built on the site would conform to the King County development regulations and be limited to a height of 35 feet in accordance with 21A.12.030. b. What views in the immediate vicinity would be altered or obstructed? Development of the site would result in a change to the visual character of the site for the nearest existing residences and roadways to that of a single- family neighborhood area. No significant views would be obstructed. c. Proposed measures to reduce or control aesthetic impacts, if any: The site plan has been developed to provide a site design layout consistent with the development regulations in place for the R-4 and/or R-6 zone. The proposed project incorporates landscape and open space areas in accordance with King County development regulations. 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Light and glare from the completed project is anticipated to be that typically generated by single-family residences, mainly occurring during the evening hours, and be associated with vehicle headlights, streetlights and residential unit lighting. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not under nonnal circumstances. c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Installation of front yard trees along the street frontages and landscaping in open space areas will help to alleviate some of the light and glare created by streetlights, headlights and residential unit lighting from the adjacent properties. The proposal will only install those street lights approved by King County and Puget Sound Energy. Typical streetlights would consist of a 150-watt, flat lens luminaire located atop a 25' light standard. 12 FOR AGENCY USE ONLY LGC REVISED 09/03/03 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? There are currently no public recreation facilities in the immediate vicinity of the site. Undeveloped King County park land lies approximately 2000' west of the site. Maplewood Park is about 1 mile southwest of the site. Maplewood Heights park is .4 miles southeast of the site. b. Would the proposed project displace any existing recreational uses? If so, describe. The project would not displace any existing recreational uses. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: The proposed project will provide a minimum of 390 square feet of open space/recreation area per single.family lot (13,650 SF) pursuant to 21A.14. The applicant proposes to construct recreational facilities on site or pay the appropriate fee-in-lieu of recreational facilities to offset any potential adverse impacts of the project. Many of the required recreational facilities required for the plat of Liberty Grove are proposed to be located in conjunction with the facilities provided by the plat of Liberty Grove Contiguous. This will allow for a more unified and centralized recreational opportunity. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. None known. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. To the best of our knowledge, there are no landmarks or evidence of any significant historic, archaeological, scientific or cultural resources known to be on or next to the site. c. Proposed measures to reduce or control impacts, if any: If any such historic or cultural evidence is encountered during construction or installation of improvements, work would be halted in the area and a state-approved archaeologist/historian would be engaged to investigate, evaluate and/or move or curate such resources, as appropriate. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. 13 FOR AGENCY USE ONLY LGC REVISED 09/03/03 The proposed project will take primary access from 1601 " Ave SE. Secondary access for the east portion of the plat will come from SE 136'" Street. Please see the attached traffic report for more details. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No. The nearest transit stop is located near the comer of SE 128"' Street and 160"' Ave SE, approximately .46 miles away from the project site. The Metro bus rout providing. service to that stop is #111. There is no bus shelter provided at that location. c. How many parking spaces would the completed project have? How many would the project eliminate? None. The proposed project will provide parking in private driveways, garages and on-street parking. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). Yes, the proposed project will require improvement of public right-of-way along 160"' Ave. SE & SE 136"' Street and construction of internal circulation roads and access tracts. All roads will be designed and constructed to current King County standards. 160th Ave. SE will be designed to the Urban Collector standard. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Assuming 10 trips per household per day, the completed project will generate approximately 360 vehicular trips per day. Please refer to the attached Traffic Report for specific details. g. Proposed measures to reduce or control transportation impacts, if any: The applicant or subsequent owner(s) will comply with Title 14 of the King County Code, which contains provisions for payment of MPS (Mitigation Payment System) Fees, Applicant will either pay the MPS fee at the time of final plat application or at the time of building permit application. If the first option is chosen, the fee paid will be the fee in effect at the time of plat application, and a note will be placed on the face of the plat stating, "All Mitigation Payment System Fees required by Title 14 have been paid." If the second option is chosen, the MPS fee paid will be the fee in effect at the time of building permit application. Contributions to projects listed in the MPS program may receive credit towards the MPS payment due. The estimated MPS fee for this project at the time of application will be, based on 14 FOR AGENCY USE ONLY LGC REVISED 09/03103 a 35 NEW (36 total) unit subdivision. The project lies within MPS zone # 452, which has a fee of $2,139 per new single-family unit. Based on 35 new units, the projected total MPS fee is $74,865. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. The completed project would result in an increased need for police and fire protection as well as emergency medical service. Additional recreational and school facilities will also be required to address the increase in demand for recreational opportunities. Extension of public sewer and water service will also be required. b. Proposed measures to reduce or control direct impacts on public services, if any. The project will be designed and constructed with adequate water pressure, properly located fire hydrants and roadways constructed to allow adequate access for fire, medic and police protection vehicles. Increased property valuation will result in increased taxes generated to support public services. Sewer service to the proposed project site will require extension of a 10" to 12" off-site sewer line from approximately 154"' Ave. SE to 162"" Ave. SE, within the existing SE 136ffi Street right-of-way. Additional improvements ma~include a 10" sewer main in 162"" St. SE., and a 8" sewer main in 158"' & 160 Ave. SE. The proponent will pay necessary school and traffic mitigation fees to offset the potential impacts to the school and transportation system. The project is located in the Issaquah School District #411. The current school impact fee is $3,924 per single-family unit. Assuming 35 new units (36 total), the total school impact fee would be $137,340. Recreational facilities will be constructed on site in accordance with the requirements of 21A.14 to offset the potential impacts on the existing recreational system or a fee-in-lieu of those facilities will be offered. 16. Utilities a. Indicate utilities currently available at the site: Electricity, Natural Gas, Water, Telephone, Sanitary Sewer, Septic System, Refuse Service, Other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. 15 FOR AGENCY USE ONLY LGC REVISED 09103/03 Water System -Water District #90 Sanitary Sewer System -City of Renton -Extension ofa10" to 12" sewer main in SE 136"' St, 10" sewer main in 162"d St SE., and a 8" sewer main in 158"' & 16o"' Ave. SE. Storm Water - Electricity: King County Puget Sound Energy Puget Sound Energy Qwest Natural Gas: Telephone: Refuse Service: Robanco Cable TV: AT&T Broadband All underground service will be constructed in conjunction with road and storm drainage construction activities C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Prepared: REVISED Hans A. Korve DMP., INC Planning Manager February 28, 2003 September 3, 2003 16 FOR AGENCY USE ONLY LGC with the development pattems of the surrounding area. The plat of Evendell located west of the Liberty proposal is currently being rezones from R-4 to R-6 as well. 12. Location of the proposal. Provide a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if available. The subject proposal is situated on three parcels totaling 7.92 acres, located within the jurisdictional boundaries of unincorporated King County in the SE Y. of Section 14 Township 23 North, Range 5 East W.M. The site is located on parcel{s) 145750-0085 and -0090. Please refer to the Preliminary Plat map for the legal description, site plan, vicinity map, and topographic map. The proposed Plat of Liberty Grove is located to the north on the west side of 160"' Ave. SE. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one):! flat I. lromnijj, hilly, steep slopes, mountainous. The project site is located on the east side of 160"' Ave. SE. (-0085 & -0090) and contains a few minor slopes in the northeast comer of the property and a non-jurisdictional drainage channel which extends through the center of the property, from north to south. The northeastem portion of the site is classified as forested uplands. The remainder of the property is pasture with two existing homes and out buildings. One Class 3 wetland has been identified in the south-central portion of the site. The finding and classification has been reviewed and approved by DOES staff. Please refer to the preliminary plat map for detailed contour infonnation. b. What is the steepest slope on the site (approximate percent slope)? According to the field topographic survey, the steepest slope on the site is approximately 5% to 10% located northeast comer of the project site. c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, and muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. According to the US Soil Conservation Service Soil Map, the site is primarily Alderwood series (AgC) d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. According to the King County Sensitive Areas Map, the property contains no hazard areas. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. 3 FOR AGENCY USE ONLY LGC 2. Air Grading of the site will be necessary to modify the site for stormwater drainage flow. The exact quantity of grading is not known at this time, however, it is anticipated that the grading activities would be designed to balance and not require import or export of soil. Grading of the individual home sites will involve the excavation of approximately 150 to 200 CY of cut and/or fill. These issues will be addressed during the building permit phase. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Some erosion could occur on-site as a result of construction activities; however, temporary erosion and sedimentation control measures to be approved by King County wilt be employed to reduce erosion impacts. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Due to the preliminary nature of the plans, the exact percentage of impervious surface associated with this project is currently unknown. The subject proposal will not exceed the maximum impervious surface area as required by KCC 21A.12.030 h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, the contractor will follow an approved temporary erosion and sedimentation control plan meeting KCC standards. Typical measures, which may be employed, include the use of silt fences, straw bales, and temporary storm drainage features. Hydro seeding exposed soils and cleared areas after construction will also reduce the potential for erosion. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. a. What types of emissions to the air would result from the proposal ~.e., dust, automobile, odors, and industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known .. Construction: Emissions and dust particulates generated primarily by construction equipment will be produced during the construction phase of this project. The amount of emissions to the air will be minimal and will occur during the actual construction of the development. 4 FOR AGENCY USE ONLY LGC Long Term Air Quality: Long-term air impacts would be those typically associated with residential land uses. Sources of long-term emissions and odor could include vehicle emissions from increased vehicle use generated by the new residential units and emissions from wood burning fireplaces (if permitted). The additional vehicular emissions in these areas are not anticipated to concentrate and therefore are not anticipated to create a health hazard to the residents or surrounding areas. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No. c. Proposed measures to reduce or control emissions or other impacts to air, if any: 3. Water If particulates become suspended during construction, frequent watering of the site during the construction phase of the project would be used to help control dust and other particulates generated on the site. This will be accomplished in accord with Section 5.4.7 of the 1998 Surface Water Design Manual. a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. · According to the King County Sensitive Areas Folio, there are no recorded streams or other water bodies on the subject site. However, field investigation has revealed the presents of a single Class 3 wetland feature in the south-central section of the site. Habitat Technologies has completed a full wetland assessment and report. The report was reviewed and .ipproved by DOES Staff on November 27, 2002. 2) Will the project require any work over, in or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. The Clas.s 3 Wetland, identified in the wetland report will be preserved and accorded the appropriate 25' buffers and 15' building setback. Grading and other construction activities are expected within 200' of the wetland feature but outside the required buffers. Appropriate measures will be taken to insure the integrity of the wetland feature during construction. Refer to the attached wetland report for complete details. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Creation of the proposed single-family lots will not require the adverse impact or placement of fill within identified wetland areas or buffers. 5 FOR AGENCY USE ONLY LGC 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan According to the King County Sensitive Areas Maps, no portion of the site lies within the 100-foot flood plain. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No. b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. None known at this time. c. Water Runoff (including stonn water): 1) Describe the source of runoff (including stonn water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. On-site storm water runoff will primarily be generated from roadways, residential structures, and associated driveways. Storm water will be collected in catch basins within the roadways and/or tight-lined from residential roof tops and conveyed to a proposed detention facility located on the project site (southwest comer of -0090). Storm water from the proposed plat of"Liberty Grove" will be transferred along 160'" Ave. SE and processed in the single stormwater facility located on parcel -0090. Discharge from the proposed facility will be piped into the existing stonn water system. Refer to the attached Level 1 storm water report for complete details. 2) Could waste materials enter ground or surface waters? If so, generally describe. Some pollutants normally associated with residential development could enter the surface water; however, the amount would be minimal since the 6 FOR AGENCY USE ONLY LGC 1) Describe special emergency services that might be required. In the event that environmental health hazards are encountered or occur during construction, all appropriate precautionary measures will be employed. Any emergency situation would be addressed by the existing resources of Fire District #25. 2) Proposed measures to reduce or control environmental health hazards, if any: State regulations regarding safety and the handling of hazardous materials will be followed during the construction process. Equipment refueling areas would be located in areas where a spill could be quickly contained and where the risk of hazardous materials entering surface water is minimized. On-site management will be equipped with mobile communications equipment at all times to contact emergency services in the event of an incident. b. Noise 1) What types of noise exist in the area, which may affect your project (for example: traffic, equipment operation, other)? The dominant source of noise in the project vicinity is traffic along 160"' Ave. SE, which bisects the proposed project. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Short-term impacts would result from the use of construction equipment during site development. Construction would occur during permitted construction hours and in compliance with King County noise standards. 3) Proposed measures to reduce or control noise impacts, if any: Construction activity will be limited to permitted construction hours and construction equipment will not be allowed to idle for continuous periods of time, which will help to mitigate the impacts of potential construction noise. Hours of operation will be posted on-site. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site(s) are currently used as single family residences. One of the existing properties contains a barn and other outbuildings associated with the keeping of live stalk. Adjacent land uses consist of a low density single- family residence. The existing plat of Liberty Lane is located to the east and the proposed plat of Evendell is located to the west. 9 FOR AGENCY USE ONLY LGC b. Has the site been used for agriculture? If so, describe. It is not believed that the site was utilized for agricultural production in the past. c. Describe any structures on the site. The property on the east side of 1601h Ave. SE , "Liberty Grove Contiguous" (145750-0085 & -0090) contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home on lot -0085 and all the associated outbuildings are proposed for removal. • 1,240 SF home located at13612160TH AV SE 98055 (145750-0085) • 2,410 SF home located at 13644160TH AV SE 98055 (145750-0090) d. Will any structures be demolished? If so, what? Yes. One of the homes and all of the out buildings are proposed for removal. e. What is the current zoning classification of the site? The project site is currently zoned R-4. The applicant has submitted a proposal to rezone the property as R-6. f. What is the current comprehensive plan designation of the site? According to the King County Comprehensive Land Use Plan, the area is designated Urban Residential -R 4-12. This designation would support the proposed rezone of the property. g. If applicable, what is the current shoreline master program designation of the site? Not applicable. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. According to the 1990 King County Sensitive Areas Folio no part of the property has been designated as sensitive. However, field investigation has identified a low value, minor Class 3 wetland feature on-site. The feature is located in the south-central segment of the project site. See attached Wetland Report. i. Approximately how many people would reside or work in the completed project? Assuming 2.5 persons per household, approximately 90 people would reside in the proposed project. j. Approximately how many people would the completed project displace? 2.5 k. Proposed measures to avoid or reduce displacement impacts, if any: 10 FOR AGENCY USE ONLY LGC ·; ,-::,3i The proposed project will provide 35 new housing units, 36 total. I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The project will be developed in accordance with applicable King County development and land use codes to ensure the project is consistent with the goals and policies of the Comprehensive Plan and applicable development regulations in effect atthe time of a complete Preliminary Subdivision application. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Approximately 35 (36 total) new middle-income housing units will be provided. b. Approximately how many units, if any would be eliminated? Indicate whether high, middle, or low-income housing. Two middle income homes will be removed. c. Proposed measures to reduce or control housing impacts, if any: Adherence to the comprehensive plan and growth management planning goals of King County would ensure that housing development is consistent with those policies stated in the applicable land use plan. 35 new homes will be built. 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? No specific building plans are included with this project; however, it is anticipated that houses built on the site would conform to the King County development regulations and be limited to a height of 35 feet in accordance with 21A.12.030. b. What views in the immediate vicinity would be altered or obstructed? Development of the site would result in a change to the visual character of the site for the nearest existing residences and roadways to that of a single- family neighborhood area. No significant views would be obstructed. c. Proposed measures to reduce or control aesthetic impacts, if any: The site plan has been developed to provide a site design layout consistent with the development regulations in place for the R-4 and/or R-6 zone. The proposed project incorporates landscape and open space areas in accordance with King County development regulations. 11 FOR AGENCY USE ONLY LGC ·,:.:.." :st 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Light and glare from the completed project is anticipated to be that typically generated by single-family residences, mainly occurring during the evening hours, and be associated with vehicle headlights, streetlights and residential unit lighting. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not under normal circumstances. c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Installation of front yard trees along the street frontages and landscaping in open space areas will help to alleviate some of the light and glare created by streetlights, headlights and residential unit lighting from the adjacent properties. The proposal will only install those street lights approved by King County and Puget Sound Energy. Typical streetlights would consist of a 150-watt, flat lens luminaire located atop a 25' light standard. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? There are currently no public recreation facilities in the immediate vicinity of the site. Undeveloped King County park land lies approximately 2000' west of the site. Maplewood Park is about 1 mile southwest of the site. Maplewood Heights park is .4 miles southeast of the site. b. Would the proposed project displace any existing recreational uses? If so, describe. The project would not displace any existing recreational uses. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: The proposed project will provide a minimum of 390 square feet of open space/recreation area per single-family lot (13,650 SF) pursuant to 21A.14. The applicant proposes to construct recreational facilities on site or pay the appropriate fee-in-lieu of recreational facilities to offset any potential adverse impacts of the project. Many of the required recreational facilities required for the plat of Liberty Grove are proposed to be located in conjunction with the facilities provided by the plat of Liberty Grove 12 FOR AGENCY USE ONLY LGC Contiguous. This will allow for a more unified and centralized recreational opportunity. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. None known. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. To the best of our knowledge, there are no landmarks or evidence of any significant historic, archaeological, scientific or cultural resources known to be on or next to the site. c. Proposed measures to reduce or control impacts, if any: If any such historic or cultural evidence is encountered during construction or installation of improvements, work would be halted in the area and a state-approved archaeologist/historian would be engaged to investigate, evaluate and/or move or curate such resources, as appropriate. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. The proposed project will take primary access from 160th Ave SE. Secondary access for the east portion of the plat will come from SE 136th Street. Please see the attached traffic report for more details. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No. The nearest transit stop is located near the comer of SE 128"' Street and 160th Ave SE, approximately .46 miles away from the project site. The Metro bus rout providing service to that stop is #111. There is no bus shelter provided at that location. c. How many parking spaces would the completed project have? How many would the project eliminate? None. The proposed project will provide parking in private driveways, garages and on-street parking. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). Yes, the proposed project will require improvement of public right--0f-way along 160th Ave. SE & SE 136th Street and construction of internal circulation roads and access tracts. All roads will be designed and constructed to 13 FOR AGENCY USE ONLY LGC :,: . - current King County standards. 160"' Ave. SE will be designed to the Urban Collector standard. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Assuming 10 trips per household per day, the completed project will generate approximately 360 vehicular trips per day. Please refer to the attached Traffic Report for specific details. g. Proposed measures to reduce or control transportation impacts, if any: The applicant or subsequent owner(s) will comply with Title 14 of the King County Code, which contains provisions for payment of MPS (Mitigation Payment System) Fees. Applicant will either pay the MPS fee at the time of final plat application or at the time of building permit application. If the first option is chosen, the fee paid will be the fee in effect at the time of plat application, and a note will be placed on the face of the plat stating, "All Mitigation Payment System Fees required by Title 14 have been paid." If the second option is chosen, the MPS fee paid will be the fee in effect at the time of building permit application. Contributions to projects listed in the MPS program may receive credit towards the MPS payment due. The estimated MPS fee for this project at the time of application will be, based on a 35 NEW (36 total) unit subdivision. The project lies within MPS zone # 452, which has a fee of $2,139 per new single-family unit. Based on 35 new units, the projected total MPS fee is $74,865. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. The completed project would result in an increased need for police and fire protection as well as emergency medical service. Additional recreational and school facilities will also be required to address the increase in demand for recreational opportunities. b. Proposed measures to reduce or control direct impacts on public services, if any. The project will be designed and constructed with adequate water pressure, properly located fire hydrants and roadways constructed to allow adequate access for fire, medic and police protection vehicles. Increased property valuation will result in increased taxes generated to support public services. The proponent will pay necessary school and traffic mitigation fees to offset the potential impacts to the school and transportation system. The project is located in the Issaquah School District #411. The current school impact FOR AGENCY USE ONLY 14 LGC fee is $3,924 per single-family unit. Assuming 35 new units (36 total), the total school impact fee would be $137,340. Recreational facilities will be constructed on site in accordance with the requirements of 21A.14 to offset the potential impacts on the existing recreational system or a fee-in-lieu of those facilities will be offered. 16. Utilities a. Indicate utilities currently available at the site: Electricity, Natural Gas, Water, Telephone, Sanitary Sewer, Septic System, Refuse Service, Other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water System - Sanitary Sewer System - Stonn Water - Electricity: Natural Gas: Telephone: Refuse Service: Cable TV: Water District #90 City of Renton -Extension of a 12" sewer main in SE 136"' St, 10" sewer main in 16Z'" St SE., and a 8" sewer main in 158"' & 16o"' Ave. SE. King County Puget Sound Energy Puget Sound Energy Qwest Robanco AT&T Broadband All underground service will be constructed in conjunction with road and stonn drainage construction activities C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Prepared: J Hans A. Korve DMP., INC Planning Manager February 28, 2003 15 FOR AGENCY USE ONLY LGC ·-,~7 ~) c..'.:· ,-,. ·...,;~--c: ·:.-:,:11!·;:;·.G;':::. ;::,.co., :;~s'. 2 ,=:· DO NOT USE THIS SHEET FOR PROJECT ACTIONS Rezone Request from R-4 to R-6 Parcel{s) # 14570-0085, -0090 and 366450-0141 D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water; emission to air; production, storage, or release of toxic or hazardous substances; or production of noise? This proposal is to rezone 12. 76 acres of R-4 land into R-6. The approved rezone would result in a minimal increase in the amount of water or air discharge from the project. The current comprehensive plan designation is for urban residential development at densities ranging from R-4 to R- 12. Achieved density is increasing from the current 4 units/acre to the proposed 4. 7 units/acre. This proposed rezone would be consistent with that designation. Proposed measures to avoid or reduce such increases are: All development will be in accord with the adopted King County Development standards. Stormwater collection and discharge will be in accord with the 1998 Surface Water Design Manual. 2. How would the proposal be likely to affect plants, animals, fish, or marine life? The proposed rezone will have no new significant impact on the existing plant or animal populations. With or without the proposed rezone, the subject property will be developed to its highest and best use. All sensitive areas will maintain the same level of integrity with or without the approval of the proposed rezone. Proposed measures to protect or conserve plants, animals, fish, or marine life? All sensitive areas will be protected in accord with the provisions of 21A.24.320. All retained sensitive areas will be provided appropriate buffers. All storm water will be detained and treated in accord with the 16 FOR AGENCY USE ONLY LGC ,, ;: :: ' -'"' ~ '· 1998 King County Surface water Design Manual and will not adversely effect the retained sensitive areas. Wetlands will only be altered in accord with KCC 21A.24.330. 3. How would the proposal be likely to deplete energy or natural resources? Electrical energy will be the primary source of power serving the needs of the project and natural gas will be made available for the purpose of heating and other needs associated with residential living. Electricity can be generated from renewable power sources such as hydro power. Proposed measures to protect or conserve energy and natural resources are: The proposed residential buildings for this project will meet or exceed the applicable single-family residential energy conservation / consumption requirements in King County and the Uniform Building Codes. 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? Therefore, there will be no increased impact to sensitive areas as a result of this rezone application. The sensitive areas on site will be protected under the provisions of KCC 21A. regardless of zoning classification. Any modification to the existing sensitive areas will be in accord with 21A.24.330. Proposed measures to protect such resources or to avoid or reduce impacts are: All development will be in accord appropriate buffers and setbacks. provided if required. with 21A.24.320 and provided the Additional buffer planting may be 5. How would the proposal be likely to affect land and shoreline use, including whether it would allow or encourage land or shoreline uses incompatible with existing plans? None The proposed rezone is consistent with the current Comprehensive Plan. Proposed measures to avoid or reduce shoreline and land use impacts are: None 17 FOR AGENCY USE ONLY LGC 6. How would the proposal be likely to increase demands on transportation or public services and utilities? The proposed development will have the effect of locally increased traffic and population which will increase the demand on existing services from the currently allowed 51 single-family residences to the proposed 60. Proposed measures to reduce or respond to such demand(s) are: Neighborhood tax revenues, taken together with Traffic and School related mitigation fees, will provide funds to continue the municipal services offered to the existing neighborhood and surrounding area. Development of the Liberty Grove project will also require improving existing unimproved or marginally improved King County right-of-way adjacent to the subject property. Primary access to both segments of the subject property will come from 160th Ave. SE. Secondary access to the eastern portion of the subject property will come from SE 1361 h Street. Frontage improvements contemplated for this project include: • Construct half-street urban neighborhood collector road improvements along the project frontage on SE 1361 " Street. The existing KC right-of-way along the northern frontage is 30'. • Construct half-street urban neighborhood collector road improvements along the project frontage on 160th Ave. SE. The existing KC right-of-way along the east and west frontage is 30' on either side. Applicant proposes to participate in the construction of the nearby Evendell sewer lift station. Completion of this facility will allow access to approximately 37 acres of land currently serviced by on-site septic systems, some of which are currently failing. In addition, several hundred acres to the north will be able to connect via gravity sewer mains to the gravity portion of the sewer system to be constructed by the Subject Plat and the Plat of Evendell as part of the SE 136th Street improvements. The proposed subdivision will also bring with it on-site recreational facilities which are currently unavailable to the immediate surrounding properties. 18 FOR AGENCY USE ONLY LGC -. ·;._:::·~.:. --··c:. 7_ Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the environment. None The Zoning Map amendment requested is needed to attain the residential density goals prescribed for the area in question, as currently designated within the King County Comprehensive Plan Map. Urban residential R-4 to 12 The re-designation of the subject property from R-4 to R-6 on the Zoning map will enable the property in question and the surrounding properties to be built out more in keeping with their maximum potential on land that is well suited for this level of density. • The proposed rezone is consistent with the current Comprehensive plan. • The proposed rezone and subsequent development will be consistent with development in the vicinity. • The proposed rezone will have no additional unmitigated impact on the transportation system beyond what would be allowed under current density limits. • The proposed rezone will not have an adverse affect on the general health, safety or welfare of the citizens of King County 19 FOR AGENCY USE ONLY LGC -® King County Road Services Division Department of Transportation 201 South Jaduon Street Seattle, WA 98104-3856 TYPE OF CERTIFICATE ~ ORIGINAL 0 CONDITIONAL May 23, 2002 Certificate # 01405 File Number: 02-05-21-02 Exnires: Mav 23 2003 CERTIFICATE OF TRANSPORTATION CONCURRENCY D Specific conditions are described on the reverse side of this certificate. Pursuant to King County Code, Chapter 14.70 as amended, this certificate confirms that the level of service standard used in the Transportation Concurrency Management program has been satisfied and sufficient road capacity is reserved for the development project described below. IMPORTANf: This certificate does not guarantee a development permit. Other transportation improvefflents and mitigation will be required to comply with Intersection Standards, Mitigation Payment System, King County road standards, and/or safety needs. I. Applicant Name and Address: WM Wayne Jones, Jr., Lakeridge Development, Inc. PO Box 146, Renton, WA 98057 2. Property Location: · a. Property Address: 13612160th Avenue SE b. Development Name: . c. Parcel Number: 1457500085,90;3664500141 3. Type of Development Permit To Be Requested: Formal Plat 4. Propos:d i.;,;,d Use: J;~g;e Family Residential · . . ' •\· 5. Z~rie'L~·~;i~n mid Reserv·e~i' Um~;··-·. a. Concurrency Zone: 763 · Community Planning Area: Newcastle . i. Commercial Project-Total Square Feet: 0 ii. Multi-fanrily ~ Number ofUnits: 0 K.C. D.D.E.S . iii. s.ingle family-Numb"ofUnits: 60 6_ This Certificate is subject to the following general conditions: a. This Certificate of Concurrency runs with the land and is transferable only to silbsequent owners of the same property for the stated development, subject to the terms, conditions and expiration date listed herein. This Certificate of Concurrency is not transf~rable to any other property and has no commercial value. This Certificate Expire~23, 20~ . . ~less you apply for the development pennit described above, prior to that date. If this requirement is not met the King County Department of Transportation reserves the option to cancel your certificate and capacity reservation. When you apply for a development permit with King County's Department of Development and Environmental Services (DDES), bring this Certificate of Transportation Concurrency as part of the development application package. If you have any questions, please call (206) 263-4722 • . ~ , .. -.· .• · .. -.. ... . . Linda Dougherty, Manager, Road Services Divts1on Department of TranspOrtation King County, Washington .t\_ FILE COPY Uf<§nsulting REcr= .. ,,,., FILE Copy July 18,2003 SEP 03 ?003 L08POoos 1\11 ,~, ~,1u11 I Y LAND USE SERVICES Mr. Wayne Jones Lakeridge Development Inc. P.O. Box 146 Renton, Washington 98057-0146 [REVl§ION] RE: Additional Sensitive Area review for Liberty Plat, King County submittal L03P005 & L03P006 Dear Mr. Jones, In response to the letter offrom King County staff I have conducted an additional review to assess the area cited in the letter as requiring additional assessment. Please consider this an addendum to the WETIAND EVALUATION AND DELINEATION REPORT AND WILDLIFE HABITAT EVALUATION, IAKERIDGE PROJECT SITE, by Habitat Technologies, November 5, 2002. The area noted in the response is located in the southeast portion of the eastern portion of the project site (see attached map). Onsite assessment of the project site following the procedures outlined in the Washington State Wetlands Identification and Delineation Manual (Wash. Manual) and the Corps of Engineers Wetlands Delineation Manual (1987 Manual) resulted in the identification of NO area that exhibited hydric soils, wetland hydrology, and hydrophytic vegetation consistent with the established criteria of both the Wash. and 1987 Manuals. This area had been impacted by prior grazing and pasture management activities, and active and on-going lawn and pasture management. ONSITE EVALUATION -WETLANDS Onsite assessment and evaluation was conducted on July 7, 2003. Wetland assessment within the project site followed the methods and procedures outlined in both the Wash. Manual and the 1987 Manual. The site is an open meadow, until recently utilized as a livestock pasture. A road drain passes under 162"d Avenue at the junction with 135th Street. This roadside ditch continues south along the side of the road thru approximately the north one-half of the project site. At approximately the northern boundary of the pasture, it turns slightly southeast and transects the southeastern portion of the project site. Rom the southern boundary of the project site, a ditch conveys surface water west to a culvert south of the eastern portion of the project site. P. 0. Box 731695 • Puyallup WA 98373 02154 Lakeridge -1 6, 253-732-6515 mheckert@qwest.net 36{f-g~~~'Yl'A~~E C Y A Q< ii FIELD OBSERVATION • Vegetation A mature managed pasture/lawn plant community dominated the evaluation site. This plant community was composed of a wide variety of invasive and seeded grasses. This plant community included colonial bentgrass (Agrostis tenuis), meadow foxtail (Alopecurvs pratensis), velvet grass (Holcus lanatus), reed canarygrass (Phalaris arondinacea), bluegrass (Poa spp.), fescue (Festuca spp.), orchardgrass (Dacty/is glomerata), quackgrass (Agropyron repens), bracken fem (Pleridium aqui/ium), western yarrow (Achil/ea /anu/osa), thistle, cats-ear (Hypochaeris spp), softrush (Juncus effusus), tansy (Tanacetum vulgare), dandelion (Taraxacum officinale), buttercup (Ranuncu/us repens), curled dock (Rumex crispus) and clover (Trifo/ium spp.). These mature trees formed open stands across the treed portion of the site. A few mature Douglas-fir trees were present along the western boundary. Additional tree species occurring onsite included Western red cedar (Thuja plicata) Sapling red alder (A/nus rvbra) were colonizing the meadow, black cottonwood (Populus trichocarpa), cherry (Pronus spp), and cascara (Rhamnus purshiana). This plant community was identified as non-hydric (i.e. typical of uplands) in character. • Soils As identified by four sample plots (data attached) throughout the project site, the site exhibited a soil profile typical of the Alderwood soil series. The soil was defined as gravelly sandy loam with a soil matrix color of dark brown (10YR 3/2) to brown (10YR 4/4). These soils did not exhibit redoximorphic features such as prominent soil mottles, oxidized root channels, or glayed soil layers within the first 20 inches of soil depth. Soils within this area did not exhibit "hydric" characteristics. • Hydrology Along the western boundary of the evaluation site, evidence of the passage of water was documented. A culvert passed under 162nd Ave. (flowing west). This surface drainage was contained in a ditch flowing south along the road to approximately half way through the evaluation area. The drainage curved slightly to the west and through the southern portion of the site. In the southern portion, the drainage ditch became less defined, and continued to the southern boundary in an undefined channel swale. From the southern boundary, the surface flow was collected into a defined ditch which flowed west to a culvert inlet. This drainage appeared to be created within an upland area, as evidenced by the soils, and was assuming hydric characteristics as a result of the direction of roof and street runoff through the site. 02154 Lakeridge • 2 Addendum Wetland Report FINDINGS AND CONCLUSIONS Onsite assessment was completed on July 7, 2003 following the methods and procedures defined within both the Wash. Manual, the 1987 Manual, and the WDNR Forest Practice Rules. This assessment identified that no area on the site, or within the immediate vicinity of the project site, exhibited all three of the established criteria for designation as "wetland". The entire site would be best defined as upland unmanaged pasture. No area was identified onsite that would meet the criteria for designation as a "stream." Thank you for allowing H & S the opportunity to assist with this project. Should you have any questions or require additional assistance please call me at 253 732-6515. ;;;J/l#f Mark Heckert Senior Wetlands Ecologist 02154 Lakeridge -3 Addendum WeUand Report Data Form Routine Wetland Determination ProjecUSite: Liberty Lakeridge ApplicanUOwner. Lakridge Development Investigator: M. _H_ec_k_e_rt ____ _ [Xf6o nom,al circumstances exist on the site? Job Number. 02154 City: Wetland Data Point SP 201 Date: July 07, 2003 County: King State: WA [ J Have vegetation, soils, or hydrology been disturbed? Community ID: Meadow Station ID: [ J Is the area a potential problem area? Plot ID: Vegetation Dorninant S~Jes ·-··--------··-Common Name _______ _ % Cover lndl<;ajo...!__ Herbaceous · X Agrostis Tenuis Sibth. X Dactylis g/omerata filuJ!b. Rubus proceros Im Bentgrass,Cotonial Grass,Orchan::I Blackberry,Hlmalaya 50 50 10 FAG FACU NI . X -·· Pseudo..!fil!fHlJ,fenziesiL(Mi~_ Flr:.Qouglas ·-··----·······-------·-·--25 _____ FACU•_ % Species tl1at are OBL, FACW, or FAC(except FAG-): 33 Cowardin Classification: Remarks appears to drain well Hydrology [XJ Recorded Data (describe in remarks) [ ] Stream, Lake, or Tide Gage [ J Aerial Photograph [ ] Other (describe in rema,1<s) Field Observations: Depth of Surface Wate~in.): O Depth to Free Water in Ptt(in.): >24 Depth to Saturated Soils(in.): >24 Remarks up slope of dttched swale Soils Primary Wetland Hydrology Indicators [ I Inundated [ ] Saturated in upper 12 inches [ ] Water mari<s [ ] Drift lines [ ] Sediment depostts [ J Drainage patterns in wetlands Secondary Hydrology Indicators [ I Oxidized root channels [ ] Water-stained leaves [ ] Local soil survey data [ J FAG-Neutral test [ I Other (explain in remari<s) Depth Hor. Matrix li!Ll_ __ _,,Co0"1or Mottle I 2nd Mottle Texture, Structull!, etc. Color Abundance Contrast 0-8 A 1 OYR 312 8-16 B 10YR 414 Hydric Soils Indicators [ ] Hlstosol [ ] Hlstic Epipedon [ J Sulfidic Odor .... [ J Probable Aquatic Moist Regime · [ J Reducing Condltlons [ J Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks appears lo drain well Wetland Determination [ I Hydrophytlc Vegetation Present [ ] Hydric Soils Present [ I Wetland Hydrology Present Remarks wetland criteria NOT met appears to drain well [ ] Concretklns Sandy Loam pebbles Coarse Sandy Loam [ ] High Organic % in Surface Layer [ I Organic Streaklng [ J Listed on Local Hydric Soils List [ J Listed on National Hydric Soils List ... [ ] Other (explain in remarks) Taxonomy: [XI Field Observations match map [ J This Data Point is a Wetland Paae4 of4 Data Form Routine Wetland Determination Project/Site: Liberty Lakeridge ApplicanUOwner: Lakridge Development Job Number: 02154 City: Wetland Data Point SP 2D2 Date: July 07, 2003 County: King Investigator: M.Heckeri __________________ -·· State: WA [X] Do normal circumstances exist on the site? Meadow [ ] Have vegetation, soils, or hydrology been disturbed? [ ] Is the area a potential problem area? Community ID Station ID: Plot ID: Vegetation Domlnam &l'!",_ies~----_____ _ Common N_ame ________ ~----·---% Cover.. Indicator . Herbaceous X Latus comiculatus Trefoil,Birds-Foot 40 FAC filHJ!ll X Rubus prooerus Blackllerry.Himalaya 90 NI --x _____ JJnwrub@ __________________ Al~Red _____________________ 50 ------FAG _______ _ % Species that are OBL, FACW, or FAC(exoept FAC..): 66 Cowardin Classification: Remarks no sign of ponding Hydrology [XI Recorded Data (desaibe in remarks) ( J Stream, Lake, or TKle Gage [ I Aerial Photograph [ I Other (describe in remarks) Field Obse,vations: Depth of Surface Water(ln.): O Depth to Free Water in Pit(in.): >24 Depth to Saturated Soils(in.): >24 Remarks in swate appears to drain well Primary Welland Hydrology Indicators [ I Inundated [ J Saturated in upper 12 inches [ I Water marks [ I Drift lines [ ] Sediment deposits [ ] Drainage patterns in wetlands Secondary Hydrology Indicator., ( ] Oxidized root channels [ ] Water-stained leaves [ ] Local soil survey data ( ] FAG-Neutral test [ I Other (explain in remarks) Soils Depth @!J_ 0-8 8-16 Hor. Matrix Color Mottle/ 2nd Mottle Textuns, Color Abundance._~eon=~tra=st~-~S~tru=ctu=re=, •=tc,, _______________ _ A 10YR3/2 NB 10YR413 Hydric Soils Indicators [ ] Histosol [ I Histic Epipedon [ J Sulfidic Odor 10YR 516 few [ ] Probable Aquatic Moist Regime [ ] Reducing Conditions . [ ·]·Gleyedorlow.Chtoma·Colors -Unit Name: Drainage Class: Remarks dttched swale Wetland Determination [XI Hydrophytic Vegetation Present [ ] Hydric Soils Present [ I Wetiand Hydrology Present Remarks wetland criteria NOT met appeara to drain well faint [ I Conaetions [ ] High Organic % in Surface Layer [ ] Organic Streaking [ ] Listed on Local Hydrtc Soils Lisi [ J Usted on National Hydric Sols List ( ] Other (explain in remarks) · Taxonomy: [XI Field Observations match map [ · ] This Data Point is a Wetland Data Form Routine Wetland Determination Project/Site: Liberty Lakerldgo Applicant/Owner: Lakridge Development Investigator: M. Heckert Job Number: 02154 City: Wetland Data Point SP 203 Date: July 07, 2003 County: King State: WA [X) Do normal circumstances exist-on the site? · · · · Community ID: Meadow Station ID: [ ] Have vegetation, soils, or hydrology been disturbed? [ ] Is the area a potential problem area? Plot ID: Vegetation Dominant Speci~s--·------- Hari,,aceous __ Common Nam1t_~------------·-% Cover ___ .ll'.ldlcator __ _ X Phleum pratense Timothy X Juncus effusus Rush,Soft 30 FACU 40 FACW+ X Senecio jacobaea Tansy ragwort X Lotus comiculatus Trefoil,Birds-Foot 20 UPL 30 FAC Plantaqomaigr Plantain,Comm~m 10 FAC+ % Species that are OBL, FACW, or FAC (except FAC-): 50 Cowardin Classification: -- Remarks Hydrology (X] Recorded Data (describe in remarks) [ ] Stream, Lake, or Tide Gage ( J Aerial Photograph ( ] other (describe in remarks) Fiekl Observations: Depth of Surface Wate~in.): o Depth to Free Water in Pit(in.): >24 Depth to Saturated Soils(in.): >24 Remarks Soils Primary Weffand Hydrology Indicators [ J Inundated [ J Saturated in upper 12 inches [ J Water marks [ J Drift lines ( J Sediment deposits [ J Drainage patterns in wetlands Secondary Hydrology Indicators [ J Oxidized root channels [ I Water-stained leaves [ J Local soil survey data [ J FAG-Neutral test [ J Other (explain in remarks) Depth Hor. Matrix (in.) Color Mottle / 2nd Mottle Texture, 0-8 ---A-10YR 3/2 Color Ab~ndance Contrast _ Structure, etc. Sandy Loam stones 8-16 B 10YR 413 Hydric So/ls Indicators [ ] Histosol [ ] Histic Epipedon [ J Sulfidic Odor ( I Probable Aquatic Moist Regime (. · l Re<luci119 Condnions. [ I Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks aeeears to drain well Wetland Oetennination [ J Hydrophytic Vegetation Present [ I Hydric Soils Present [ J Wetland Hydrology Present Remarks wetland criteria NOT met appears to drain well -----· Sandy Loam stones ( J Concretions ( ] High Organic.% in Surface Layer [ ) Organic Streaking [ J Listed on Local Hydrlc Soils List · · · · [ · J'Llsted on NationalHydric Soils List [ ] other (explain in remarks) Taxonomy: [XI Field Observations match map [ J This Data Point Is a Wetland Paae2 of4 Data Form Routine Wetland Determination Project/Site: Liberty Lakeridge ApplicanUOwner: Lakridge Development Investigator: M. Heckert [X] Do normal circumstances exist on the srte? Job Numbec 02154 City: Wetland Data Point SP 204 Date: July 07, 2003 County: King State: WA Community ID: Meadow [ J Have vegetation, soils, or hydrology been disturbed? [ ] Is the area a potential problem area? Station ID: Plot ID: Vegetation Dominant Specjes -··---·----- Herbaceous Common Name ___________ % Cover __ Indicator X Agropyron repens Quackgrass 20 FAGU X Agrostis Tenuis Sibth. Bentgrass,Colonial 20 FAG X Lotus comiculatus Trefoil,Birds-foot 60 FAG X Alopecurus geniculatus Foxtail.Meadow 30 FACW+ !>lm!h. __ X ____ .. __ Rubus laciniatus _______ ________ Blackbe'!}',Cut-Leaf ____ __________ 30 ______ __ FACU+ __ _ % Species that are OBL, FACW, or FAC(except FAG-): 60 Cowardin Classification: Remarks Hydrology [ J Recorded Data (describe in remarks) [ J Stream, Lake, or ride Gage [ J Aerial Photograph [ ] Other (describe in remarks) Field Observations: Depth of Surfaca Water(in.): O Depth to Free Water in Pil(in.): >24 Depth to Saturated Soils(in.): >24 Remarks Primary Welland Hydrology Indicators [ ] Inundated [ J Saturated in upper 12 inches [ ] Water marks [ ] Drift lines ( J Sediment deposits [ ] Drainage patterns in wetlands Secondary Hydrology Indicators [ J Oxidized root channels [ J Water-ined leaves ( ] Local soil survey data [ ] FAG-Neutral test [ J Other (explain in remarks) Soils Depth (iri,L 0-12 12-18 Hor. Matrix Color Mottle/ 2nd Mottle Texture, Color Abundance Contrast Structure etc. Sandy Loam stones Sandy Loam stones none A 10YR3/2 NB 10YR413 10YR 516 few faint Hydric Soils Indicators [ J Histosol [ J Histic Epipedon [ ] Sulfidic Odor [ I Probable A~uatic Moist Regjme . [ J Fleducing Co(iditlons ... [ J Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks sandy gravelly loam Wetland Determination [X] Hydrophytic Vegetation Present [ J Hydric Soils Present ( J Wetland Hydrology Present Remarks Wetland criteria NOT met appears to drain well [· J Concretions [ J High Organic % in Surface Layer [ J Organic Streaking ( . J Listed on-Local Hydric Solis list . [ J Listed on National Hydric Soils List [ J Other (explain in remarks) Taxonomy: [X] Field Observations match map [ J This Data Point is a Wetland ""'---,t _, A • • I RE1.1 VED 7 / " I 2.5 '---) 0 0 ,- \ \ \ LOC&TBD IN TBB 80U1'B B4J,Jf OJ' 8BCl'ION 8, 'J'OWN8IIJP II NORl'B, BANGB 7 IWIT, WILUIIB'lTB NBBIDW KING COUNTY, WASBING'ION 'b 0 ~------- D N [raffic Consultants! PO Box 547 Preston, WA 98050-0547 425-392-1308 Date: To: From: Subject: April 17, 2007 Ty Pendergraft Eagle Creek Land Development Gary A. Norris, P.E., P.T.O.E. ON Traffic Consultants Threadgill/Ca valla/Liberty Gardens Response to KC Traffic Comment This memorandum was prepared to address a question raised by Kris Langley KCDOT, at the February meeting of the Threadgill et al applicants with King County DOES. Specifically, Kris requested an evaluation of the following: If signalization were warranted at the 156 1h Avenue SE/SE 136 1h Street intersection would: I. Would some of the southbound traffic demand shift from the 162°d Avenue SE/SE 1441h Street/l56'h Avenue SE/SR 169 route to the SE l36'h Street/1561 " Avenue SE/SR 169 route? 2. What is your professional opinion about the reduction along 162°d Avenue SE and the increase along SE l 36'h Street, if any? To address these questions, I will respond in the order they arc presented. Signalization First, the questions are based on the premise that signalization would be warranted. A review of the prevailing traffic volumes and the MUTCD traffic signal warrants indicate the intersection does not meet applicable warrants in the 2008 with project volume scenario. Warrants considered included Warrant 1 -Eight Hour Warrant, Condition A and B; Warrant 2 -Four-Hour Vehicular Volume; Warrant 3 -Peak Hour; and Warrant 7 -Crash Experience. (There have been no accidents during the latest three year period evaluated). Projecting the 2008 with project volumes at the current growth rate (6 percent per year), signal warrants would be met in 17 years or approximately 2025. Unless, the County is willing to consider signalization without warrants, it is unlikely that a signal will be constructed in the time frame of this development proposal. fo) \g@@ Q W @@ MA.IN fl\.E coPY { '~D r,..\ 0 .)._ \;' lJi) JUL O 2 2007 K.C, D.D.E.S, MA\N FILE COPY Southbound Traffic Shift If the SE l 36'h Street/l 56'" Avenue SE intersection were signalized, it appears that the anticipated delay for eastbound and westbound traffic will be significantly higher than it currently is under the two-way stop scenario. As presented in the TIA (Technical Appendix), the approach delay for the eastbound and westbound traffic under the two- way stop control is 125.9 seconds and 63.9 seconds respectively. With signalization this increases to 40 l .4 seconds and 241.4 seconds respectively. This condition results from· an optimized signal timing which seeks to minimize overall intersection delay. Since the eastbound and westbound PM peak hour volumes are insignificant, 36 and 20 vph respectively, compared to the north and south bound traffic, 415 and 949 vph respectively, Syncro seeks to minimize the delay by providing more "green time" to the north -south movement while the east -west movements wait. Therefore, if the signal were to operate in an optimized manner significant delay would be realized on SE 136'h Street which would compel the motorist to seek other routes. An evaluation of the travel time via both routes indicates under norrnal circumstances, where the delav realized at the SE 136'h Street/156th Avenue SE intersection didn't have such an impact on route selection, the plat of Threadgill would select the SE 136th Street/! 56'h Avenue SE route to SR 169 whereas the other two plats, Liberty Gardens and Cavalla would select 162"d Avenue SE. This is based on the assumption that the motorist will select the minimum travel time path. Obviously, human nature doesn't always work that way. lfthe extension of 162"d Avenue SE is not constructed, then the SE 136'h Street/l 56'h Avenue SE route has the faster travel time for all three plats and it is assumed. Professional Opinion Regarding Diversion Based on the foregoing analysis and previous analysis of traffic flow patterns m this area, it ts my opirnon that traffic from these plats bound to/from the south and SR 169, will always seek altemative routes to the l56'h Avenue SE/SE 136'h Street route because of the delay encountered at this intersection. The construction of l 62"d Avenue SE will not change this conclusion although it will offer a faster travel time for Cavalla and Liberty Gardens. The plat of Threadgill will not benefit from the construction of l 62"ct Avenue SE other than through the provision of another alternative route. I hope this addresses the question in a satisfactory manner, If you have any questions, please call me at (425)765-5721 or by e-mail at gary.norris@comcast.net Thanks, Gary 2 -(416) 749 t(151)<48i (643) 676 -1 1 (64) 378 -,_ ' ~~ "' - ..., -ON L §' ;:.;:. (0) 4 ----(624) 1049 J i l t(9) 5J (1) ,1_j 1 t' (891) 863 -.. ., "'J:l (16) 63-,_ ~o- ' ~-:g -- ..,_ L ..:;::...::;, 1 j l -(633) 419 (6) 24 _j (190) 653-.. SE 128th Street "' "' "' "' ... _"' L<1> 7 885: -(0)1 J iL t(3} 6 (11) 13 _j 1 t ' (1) 1-~~~ (20} 22 f _..,_ ...,_o -N-..,-e. ,.....:ou:i L _;::--(9) 0 "' ... 0 ----(4) 3 Ji l t(3)1 (3) '_j (3) ·-(12) 11, lt, (XXX} -AM PEAK XXX -PM PEAK DN TRAFFIC CONSULTANTS w "' • , C • > " ~ ;;; :" w "' • , C ~ -( £ 0 '.£ £ 0 w w "' • ' C • > -( £ .. '.£ SE 132nd Street SE 134th Street w "' • , C • > -( w £ w V, "' • m • , '.£ ' C i • > > "' " £ £ "' w '.£ '.£ SE 136th Street Cavalla Liberty Gardens SE 144th Street 2008 TRAFFIC VOLUMES W/0 PROJECT PLAT OF THREADGILL CA VALLA LIBERTY GARDENS FIGURE 6 (4) 10 -1 ~ §: SE 128th Street L(B) 6 .:. L <sH e -(e) 6 Lr (32) 21 (XXX) -AM PEAK XXX -PM PEAK r 117%1 w "' • 0 ' • > < £ ~ ~ (4) 10 t l(Oe w (4) (8) d r(2) 8 i "' E w "' • 0 ' • > < ~ 0 :£ ~J (2) 2- (2) .&.. S"'j r"'e 5"" (7) w "' • 0 ' i < ~ ::; :e SE 132nd Street r .. e SE 134th Street s, ~~srhreadgill (46) .d! w V, • 0 C • > < 5 ~ :e -(1) J 117%1 w "' • 0 C • > < w 5 "' • m 0 :e ' • > < £ "' ~ SE t 36th Street Cavalla Liberty Gardens SE 144th Street AM PEAK PM PEAK TOTAL OUT IN TOTAL OUT IN lHREADGILL 10 J 7 14 g 5 CAVALLA 26 7 19 34 21 13 LIBERTY GARDENS 29 8 21 38 24 14 ON TRAFFIC CONSUL TAN TS PROJECT GENERATED TRAFFIC PLAT OF THREADGILL CAVALLA LIBERTY GARDENS FIGURE 7 \ I I I '-- .~ ~ .._ I UJ "' UJ ;;: I ~ I f- "' ';' ~ j: .._ ! ~ ii, ' ' --- '\ -CL--~; i ~ .._ --- <' -- r, lS Hl9£L 3S I I " "" ~ I ' .._ I UJ "' UJ 4, > "' I f- <O ';' ~ .._ ·" 1-- I : CHAD ARMOUR, LLC May 16, 2007 Mr. Curtis Schuster KBS DeveloJ;>ment Corporation 12320 NE 8 Street, Suite 100 Bellevue, Washington 98005 Subject: Conceptual Wetland Mitigation Plan Cavalla Preliminary Plat King County, Washington Dear Mr. Schuster: 6500 126th Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com The following plan presents our approach to mitigating for unavoidable impacts to the buffer of a Category Ill wetland. PROPOSED DEVELOPMENT PLAN KBS Development Corporation (Proponent) proposes to construct 34 single-family homes on the 9.4-acre Cavalla site (Figure 1 ). To do so, it will be necessary to construct a new road (162°d Avenue SE). The road will impact a total of 887 square feet (sf) of Category Ill wetland buffer (Table 1 and Figure 2). We understand that the planned development is subject to the King County (County) Critical Areas regulations. We also understand that the Proponent proposes to make up for unavoidable impacts to the buffer using the Mitigation Reserves Program. CONCEPTUAL MITIGATION PLAN The plan is to: • Fill a portion of the wetland buffer; and • Pay the County a fee to create a 887 sf wetland buffer off of the site. EXISTING CONDITIONS According to 8-12 Wetland Consulting (2004) a wetland is dominated by immature red alder (A/nus rubra) trees, salmonberry (Rubus spectabilis) shrubs, and lady fern (Athyrium filix-femina) is located off of the site near the southwest corner of the same. Based on our functional assessment, the wetland functions as a Category 111 wetland (Attachment A). The buffer extends into the proposed 162nd Avenue SE right-of-way. Assuming that the provisions of KKC 21A.24.325A3b apply, constructing the road will unavoidably impact a total of 887 sf of wetland buffer. CONSTRUCTION PLAN ~-@g~lg@ The plan is to pay the County the equivalent fee to enhance a degrad -site buffer t\\\\1 covering 887sf. \\j\... \\ ?. MAIN FILE COPY . ,~ o.E.S, C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC MAIN FILE COPY 1 I( l ' o. ,. 05/16/07 I /JI Pet!'O/ Cavalla Mitigation Plan King County, Washington a based on a drawing prepared by B-12 areas' b Assumes a 50 ft buffer (exercise the buffer reduction option) Off-Site Buffer Enhancement We assume that: • It will be necessary to purchase urban land; KBS Development • A total of 12 trees and 24 shrubs will be installed in a degraded buffer at a rate of 0.041 plants/sf (Table 2); • A mixture of native herbaceous plant species will be broadcast seeded and hydroseeded on the degraded buffer; • 1 snag and 1 log will be installed in the degraded buffer; and • Compost will be added around each of the installed plants in a circle 3 ft in diameter and 3 inches (in) deep, and the site will be irrigated by way of a permanent irrigation system (Attachment B). MONITORING The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for monitoring the off-site buffer for at least three years following installation. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for monitoring associated with the proposed buffer fill and subsequent mitigation efforts. MAINTENANCE The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for maintenance of the off-site buffer during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for maintenance associated with the proposed buffer fill and subsequent mitigation efforts. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 2 05/16/07 Cavalla Mitigation Plan KBS Development King County, W:c:a=-sh"-'i'-"nga.:t::.:on-'---------~--------------- Table 2 -Plant and Habitat Amenit Installation Guide' 1 • 887 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve ' total average density is O. 041 plants/sf CONTINGENCY PLAN The Proponent has included costs in the Mitigation Reserves Program "Fee-In-Lieu Worksheet" to allow for a contingency plan should deficiencies in the off-site buffer be discovered during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for contingency measures associated with the proposed buffer fill and subsequent mitigation efforts. SCHEDULE The Proponent anticipates paying the "Fee-In-Lieu" at the first available opportunity following the receipt of the necessary approvals from the County. We understand that this may be after Preliminary approval and prior to construction. LIMITATIONS Work for this project was performed, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of KBS Development Corporation and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this mitigation plan is the responsibility of the permitting authority. Accordingly, the mitigation plan developed for this plat should be reviewed by the C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 3 05116107 Cavalla Mitigation Plan King County, Washington KBS Development appropriate permitting authority prior to committing to detailed planning and design activities. Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC WA~ Chad Armour Principal Attachments: Figure 1 -Vicinity Map Figure 2 -Site Plan Attachment A -Wetland Rating Form -Western Washington Attachment B -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County DDES C:/Jobs/BCE/Cavalla/Fee In-lieu Letter.doc Chad Armour, LLC 4 05/16/07 FIGURES t~ 1·1. I ['lil, ' v.- DN TRAFFIC CONSULTANTS VICINITY MAP FIGURE 1 PLAT OF THREADGILL CA VALLA LIBERTY GARDENS ' • ' ' . I l'.\,1c:-: .. I 43C05'.J'.:I<\- r I '· ' • ' I I I ' !HA'"' 'k · sron.ti"P9No "J,flCf'I 1.3:<ti.%\.1"_ Buffer Reduction Area ,. V(B87 SF) a~" ·. ' ' '\ I 50' .. ", ~ r Wetland . y-' Buffer : I \ _ _.:_f,.,Y",.. II N vv / I ' I I t )9 ' / I I I>' I 'A>!(> . ~~ f, I~~' I r,JIJ;c,'.i,;C, " A,S -:~!·C I I I I '· .. • . (( Cavalla ?H ' . , -:;; • .. ' l ' i ' • IMC) ·c )>'' '·I'.?' .. ' ' "' ,.._ r·~cicsu \4~JSJ :ns Wl-lOPCS~·)PI Al 01'-111-lf-'R'I': GA1''.)C:N!O "LC:~ :...~,4PCCJLI; Liberty Gardens 0 I I I I I I I',\ iC __ i r·,\~c=. ' ,.:.;~c;sc,:oRi: !1 1..]CfoCCt.1~· I I ,· ,--.-·f <\\>C· /-'-------:;~-j --V 20 / !t-'I\C.' '/1 r'Ailr< ' 16 i • ' . I 15 JJ ~ CCc;"cJ,.-.------.---! ,,· " ' ,~ ,,1 /t.-::-{; 200 I: 100 II I I I Scale in Feel II FIGURE 2: SITE PLAN KBS·Cavalla Site King County, Washington D,.TE: 05/16/07 10: 12am DWG NAM(; G: \pro jeet\Oienb\o~mour\1<8S-162rid Ave_Cowllo_ Threodg~I\Co110Uo02.d,..g 1J I Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 i ' I , ATTACHMENT A Wetland Rating Form V./etland name or number WETLAND RA TING FORM -WESTERN WASHING TON Version 2 -Updated July 2006 to increase accuracy and reproducibility among users Name of wetland (if known): Date of site visit: 'iJ.!:_</J,; ~ Rated by Uc.£ ~r..,,,..,_r Trained by Ecology? Yes_No /oate of training, __ _ . SEC: Ji TWNSHP: 2-}NRNGE: $!:--Is Sff/R in Appendix D? Yes /No_ Map of wetland unit: Figure__ Estimated size __ _ SUMMARY OF RATING Category based on FUNCJIONS provided by wetland I II III / IV ------ Category I = Score >=70 Category II= Score 51-69 Category III = Score 30-50 Category JV = Score< 30 Score for Water Quality Functions Score for Hydrologic Functions Score for Habitat Functions TOTAL score for Functions Category based on SPECIAL CHARAj'.'TERISTICS of wetland I_ II_ Does not Apply_/_ Final Category (,h_ <ho "h~h"'" u<ogo,y from ,OO.e) I aj Summary of basic information about the wetland unit Natural Herita e Wetland Bo Mature Forest Old Growth Forest Coastal La oon Interdunal None of the above Wetland Rating Fonn -western Washington version 2 Flats Freshwater Tidal Check if unit has multiple HGM classes resent August 2004 Wetland name or number Does the wetland unit being rated meet any of the criteria below? lfyou answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. SP 1. Has the wetland unit been documented as a habitat for any Federally listed Threatened or Endangered animal or plant species (TIE specie,)? For the purposes of this rating system, "documented" means the wetland is on the a ro riate state or federal database. SP2. Has the wetland unit been documented as habitat for any State listed Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note: Wetlands with State listed plant species are cate orized as Cate o I Natural Herita e Wetlands see . 19 of data form . SP3. Does the wetland unit contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its junctions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part ofthe data sheet you will need to determine the Hydrogeomorphic Class of the wetland being rated The hydrogeomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. Wetland Rating Fonn -western Washington version 2 2 August 2004 Wetland name or number Classification of Wetland Units in Western Washington ~,~---,I~ t -• '• -~ t, -i'. .~~-~ ~~---~~---~ -, r' 'j • -l ~:-~-~,-: ~7~):~,~f~--'' ~ --'~ I:,~·~: "~~·~,-•-~-' -- 1 : "'' , ' ' '' ' ,,-' ' ' I " -·,. -" ' : -' • ; ---' ,' ' -, : ; :::-' ' ' . ' . . : ---~""'-"---~----~ -~·--~·~ ...... -------'--'-~---__ , ---~--~----~-~-------~ •"'-.. , ---------~---! l. ~water levels in the entire unit usually controlled by tides (i.e. except during floods)? ~go to 2 YES -the wetland class is Tidal Fringe If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES-Freshwater Tidal Fringe NO-Saltwater Tidal Fringe (Estuarine) If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. !fit is Saltwater Tidal Fringe ii is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (seep. ) . . 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. ~dwater and surface water runoff are NOT sources of water to the unit. (7., go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both of the following criteria? _The vegetated part of the wetland is on the shores ofa body of permanent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; ~At least 30% of the open water area is deeper than 6.6 ft (2 m)? ~ gu to 4 YES-The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the ,x\tire wetland unit meet all of the following criteria? _LThe wetland is on a slope (slope can be very gradual), __ /The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without /distinct banks. _/_ 1The water leaves the wetland without being impounded? NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <Jft ~and less than 1 foot deep}. NO -go to 5 c~ The wetland class is Slope Wetland Rating Form -western Washington version 2 3 August 2004 Wetland name or number 5. Does the entire wetland unit meet all of the following criteria? __ The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river __ The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with waler when the river is ot flooding. go to 6 YES -The wetland class is Riverine 6. s entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means that any outlet, if present, is higher than the interior of the wet!~. NO -go to 7 ~ The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO -go to 8 YES -The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM clases. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. Depressional + Riverine along stream within boundary De ressional + Lake-frin e Salt Water Tidal Fringe and any other class of freshwater wetland Depressional De ressional Treat as ESTUARINE under wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating Form -western Washington version 2 4 August 2004 Wetland name or number D D D D D 1. Does the wetland unit have the potential to improve water quality? D 1.1 Characteristics of surface water flows out of the wetland: Unit is a depression with no surface water leaving it (no outlet) points= 3 Unit has an intermittently flowing, OR highly constricted permanently flowing outlet points~ 2 Unit has an unconstricted, or slightly constricted, surface outlet (permanently flowing) points= 1 Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a man-made ditch points= 1 (If ditch is not permanently flowing treat unit as "intermittently flowing") Pt0vide hgto or. dr'<lwitl S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (useNRCS definitions) YES NO points -4 oints -0 ¢ D 1.3 Characteristics of persistent vegetation (emergent, shrub, and/or forest Cowardin class) Figure_ Wetland has persistent, ungrazed, vegetation>~ 95% of area points ~ 5 Wetland has persistent, ungrazed, vegetation>~ 1/2 of area points -3 -:2._ Wetland has persistent, ungrazed vegetation> -1/10 of area points-I J Wetland has persistent, ungrazed vegetation <1/10 of area points~ 0 Ma .. of Cowardin ve·· etatic:m·classes D 1.4 Characteristics of seasonal ponding or inundation. This is the area of the wetland unit that is ponded for at least 2 months, but dries out sometime during the year. Do not count the area that is permanently ponded. Estimate area as the average condition 5 out of JO yrs. Area seasonally ponded is > Y, total area of wetland Area seasonally ponded is> Y. total area of wetland Area seasonally ponded is< Y. total area of wetland ¢ --/ D Total for D l Add the points in the boxes above I ..5 I ~-~-----------------------------------+----D D D 2. Does the wetland unit have the opportunity to improve water quality? (seep. 44) Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the following conditions provide the sources of pollutants. A unit may have pollutants coming from several sources, but any single source would qualify as opportunity. -Grazing in the wetland or within 150 ft -Untreated stormwater discharges to wetland 7 Tilled fields or orchards within 150 ft of wetland A stream or culvert discharges into wetland that drains developed areas, residential areas, / farmed fields, roads, or clear-cut logging _:L_ Residential, urban areas, golf courses are within 150 ft of wetland multiplier Wetland is fed by groundwater high in phosphorus or nitrogen -~ ~ YES NO multi lier is l Multiply the score from DI by D2 JO Add score to table on . 1 Wetland Rating Form -western Washington version 2 5 August 2004 Wetland name or number D D D D 3. Does the wetland unit have the potential to reduce flooding and erosion? D 3.1 Characteristics of surface water flows out of the wetland unit Unit is a depression with no surface water leaving it (no outlet) points= 4 Unit has an intennittently flowing, OR highly constricted permanently flowing outlet points= 2 Unit is a ''flat" depression (Q. 7 on key), or in the flats class, with pcnnanent surface outflow and no obvious natural outlet and/or outlet is a man-made ditch points=--I (Jf ditch is not permanently flowing treat unit as "intermiJtently flowing") Unit has an unconstricted or sli htl constricted, surface outlet ermanentl oints = 0 D 3.2 Depth of storage during wet periods Estimate the height of ponding above the battom of the outlet. For units with no outlet measure from the surface of permanent water or deepest part (if dry). Marks of ponding are 3 ft or more above the surface or bottom of outlet points= 7 The wetland is a "headwater'' wetland" points= 5 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to< 2 ft from surface or bottom of outlet points= 3 Unit is flat (yes to Q. 2 or Q. 7 on key) but has small depressions on the surface that trap points= I oints = 0 D 3.3 Contribution of wetland unit to storage in the watershed Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself The area of the basin is less than 10 times the area of unit The area of the basin is IO to 100 times the area of the unit The area of the basin is more than JOO times the area of the unit points= 5 points = 3 points= 0 Entire unit is in the FLA TS class oints = 5 1-~=c.c....=c..ccc...ccc...=~==-"-==--------------------'==--"---lo---- 1-D-1-_T_o_t_a_1 _ro_r_D_3 ______________ Ad_'d_1_h_ep_a_in_1s_in_1h_e_b_o_x_e_s_a_b_o_v_e_+• __ g_ D D 4. Does the wetland unit have the opportunity to reduce flooding and erosion? (seep. 49) D Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a structure such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater in areas where damaging groundwater flooding does not occur. Note which of the following indicators of opportunity apply. ~etland is in a headwater ofa river or stream that has flooding problems -Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface runoff water that might otherwise flow into a river or stream that has flooding problems ther --------------~ multi lier is 2 NO multi lier is 1 TOTAL -Hydrologic Functions Multiply the score from D 3 by D 4 Add score to table on p. 1 Wetland Rating Form -western Washington version 2 6 August 2004 multiplier Pages 7 through 12 are not applicable \Vetland name or number H I. Does the wetland unit have the potential to provide habitat for many species? HI.I Vegetation structure (<ee p. 72) Check the types of vegetation classes present (as defined by Cowardin)-Size threshold for each class is % acre or more than 10% of the area if unit is smaller than 2.5 acres. __ Aquatic bed __ Emergent plants ___ Scrub/shrub (areas where shrubs have >30% cover) ___ Forested (areas where trees have >30% cover) Ifth,y(,nit has a forested class check if ____i,!".:The forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the forested polygon Add the number of vegetation structures that qualify. If you have: Map of'CO~atdift vegeta:tion classes H 1.2. Hydroperiods (seep. 73) 4 structures or more 3 structures 2 structures I structure points -4 points -2 points -I oints -0 Check the types of water regimes (hydroperiods) present within the wetland The water regime has to cover more than JO% of the wetland or~ acre to count. (see text/or descriptions of hydroperiods) __ Permanently flooded or inundated 4 or more types present __ Seasonally flooded or inundated 3 types present _____j')ccasionally flooded or inundated 2 types present __ / S, aturated only I type present ___;Permanently flowing stream or river in, or adjacent to, the wetland __ / Seasonally flowing stream in) or adjacent to, the wetland points -3 points -2 point -I points -0 __ Lake-j"ringe wetland = 2 points __ Freshwater tidal wetland = 2 points Map of hydroperiods H 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least IO ft2 • (different patches of the same species can be combined to meet the size threshold) You do not have to name the species. Do not include Eurasian Mi/foil, reed canarygrass, purple /oosestrife, Canadian Thistle If you counted: > 19 species List species below if you want to: 5 -19 species < 5 species points = 2 points= I points= 0 F"rguni _ I I Total for page~ Wetland Rating Form -western Washington version 2 13 August 2004 Wetland name or number H 1.4. Interspersion of habitats (seep. 76) igure _ Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H 1.1), or the classes and unvcgetated areas (can include open water or mudflats) is high, medium, low, or none. ~ ~ None~ 0 points ,,. --_ ·-.'.>;:· .. o·_ ... Low~ I point ~ High ~ 3 points Moderate ~ 2 points [riparian braided channels] NOTE: lfyou have four or more classes or three vegetation classes and open water the ratin is alwa s "hi h". Use map of Cowardin ve elation classes H 1.5. Special Habitat Features: (seep. 77) Check /he habila/ features /hat are present in /hewer/and. The number of checks is the / number of points you put into the next column. ___ {Jt.\rge, downed, woody debris within the wetland (>4in. diameter and 6 ft long). _/~stt,anding snags (diameter at the bottom> 4 inches) in the wetland ___ Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (Im) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (!Om) ___ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet turned grey/brown) ___ At least 'It acre of thin-stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated. (structures for egg-laying by amphibians) ___ Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated in early printings of the manual on page 78 is an error. ~-------------~~-~-~----~~~---------4----- H 1. TOT AL Score -potential for providing habitat ~ I Add the scores om Hl.1, Hl.2, Hl.3, Hl.4, Hl.5 J '-------------==cc.cc....:.c.::.:._=-,..c..:..cc:....:..:..:..:..c..c..c.c..c=--'--'-'-=-'=.c.-'-'-----'-'~---- Comments Wetland Rating Form -western Washington version 2 14 August 2004 \Vetland name or number H 2. Does the wetland unit have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Choose the description that best represents condition of buffer ofwetland unit. The highest scoring criterion that applies to the wetland is to be used in the rating. See text/or definition of "undisturbed." -I 00 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed part of buffer. (relatively undisturbed also means no-grazing, no landscaping, no daily human use) Points= 5 -}?O m (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > /;~% circumference. Points= 4 -50 m ( 170ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points= 4 -100 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 25% circumference, . Points= 3 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference. Points = 3 If buffer does not meet any of the criteria above -No paved areas (except paved trails) or buildings within 25 m (80ft) of wetland> 95% circumference. Light to moderate grazing, or lawns are OK. Points= 2 -No paved areas or buildings within 50m of wetland for >50% circumference. Light to moderate grazing, or lawns are OK. Points= 2 -Heavy grazing in buffer. Points= I -Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g. tilled fields, paving, basalt bedrock extend to edge of wetland Points= 0. -Buffer does not meet any of the criteria above. Points= I Aerial ohoto showinaJ)uff~rs H 2.2 Corridors and Connections (seep. 81) H 2.2.1 ls the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 150 ft wide, has at least 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dams in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corrido~. YES= 4 points (go to H 2.3) NO go to H 2.2.2 H 2.2.2 Is the wetland part of a relatively undisturbed an n roken vegetated corridor (either riparian or upland) that is at least 50ft wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake-fringe wetland, if it does not have an undisturbed corridor as in the questio~v ? YE · points (go to H 2.3) NO= H 2.2.3 H 2.2.3 Is t e wetland: within 5 mi (8km) of a brackish or salt water estuary OR within 3 mi of a large field or pasture (>40 acres) OR within I mi of a lake greater than 20 acres? YES= I point NO = 0 points Wetland Rating Form -western Washington version 2 15 Total for page (, August 2004 Wetland name or number H 2.3 Near or adjacent to other priority habitats listed by WDFW (seep. 82) Which of the following priority habitats are within 330ft ( I OOm) of the wetland unit? NOTE: the nections do not have to he relatively undisturbed. se are DFW definitions. Check with your local DFW biologist if there are any questions. Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. __ Aspen Stands: Pure or mixed stands of aspen greater than 0.8 ha (2 acres). __ Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. __ Old-growth forests: (Old-growth west of Cascade crest) Stands of at least 2 tree species, forming a multi-layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre)> 81 cm (32 in) dbh or> 200 years ofage. __ Mature forests: Stands with average diameters exceeding 53 cm (21 in) dbh; crown cover may be less that 100%; crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old- growth; 80 -200 years old west of the Cascade crest. __ Prairies: Relatively undisturbed areas (as indicated by dominance of native plants) where grasses and/or forbs form the natural climax plant community. __ Talus: Homogenous areas of rock rubble ranging in average size 0.15 -2.0 m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. __ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages __ Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component of the stand is 25%. __ Urban Natural Open Space: A priority species resides within or is adjacent to the open space and uses it for breeding and/or regular feeding; and/or the open space functions as a corridor connecting other priority habitats, especially those that would otherwise be isolated; and/or the open space is an isolated remnant of natural habitat larger than 4 ha ( 10 acres) and is surrounded by urban development. __ Estuary/Estuary-like: Deepwater tidal habitats and adjacent tidal wetlands, usually semi- enclosed by land but with open, partly obstructed or sporadic access to the open ocean, and in which ocean water is at least occasionally diluted by freshwater runoff from the land. The salinity may be periodically increased above that of the open ocean by evaporation. Along some low-energy coastlines there is appreciable dilution of sea water. Estuarine habitat extends upstream and landward to where ocean-derived salts measure Jess than 0.5ppt. during the period of average annual low flow. Includes both estuaries and lagoons. Marine/Estuarine Shorelines: Shorelines include the intertidal and subtidal zones of beaches, and may also include the backshore and adjacent components of the terrestrial landscape (e.g., cliffs, snags, mature trees, dunes, meadows) that are important to shoreline associated fish and wildlife and that contribute to shoreline function (e.g., sand/rock/log recruitment, nutrient contribution, erosion control). If wetland has 3 or more priority habitats; 4 points If wetland has 2 priority habitats; 3 points If wetland has I priority habitat; I point No habitats; 0 points Note: All vegetated wetlands are by definition a priority habitat but are not included in this list. Nearby wetlands are addressed in question H 2. 4) Wetland Rating Form -western Washington version 2 16 August 2004 \Vetland name or number H 2.4 Wetland Landscape (choose the one description a/the landscape around the wetland that best.fits) (seep. 84) There are at least 3 other wetlands '.Vithin Yi mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points -5 The wetland is Lake-fringe on a Jake with little disturbance and there are 3 other lake-fringe wetlands within l/2 mile points -5 There are at least 3 other wetlands within 'I, mile, BUT the connections between them are disturbed points -3 The wetland is Lake-fringe on a Jake with disturbance and there are 3 other Jake-fringe wetland within 'I, mile points -3 There is at least I wetland within \I, mile. points -2 There are no wetlands within V2 mile. points ~ 0 H 2. TOT AL Score -opportunity for providing habitat Add the scores from H2.l,H2.2, H2.3, H2.4 TOT AL for H 1 from page 1 4 Total Score for Habitat Functions -add the points for H I, H 2 and record the result on Wetland Rating Form -western Washington version 2 17 p. 1 August 2004 3 ----- I Jc) I ------0 ----· 1 _s; Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. SC 1.0 Estuarine wetlands (seep. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? -The dominant water regime is tidal, -Vegetated, and -With a salinity greater than 0.5 ppt. YES = Go to SC 1.1 NO_/ SC I. I Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? YES = Cate o I NO o to SC 1.2 SC 1.2 Is the wetland unit at least 1 acre in size and meets at least two of the following three conditions? YES = Category l NO= Category I! -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. If the non-native Spartina spp. are the only species that cover more than 10% of the wetland, then the wetland should be given a dual rating (1/11). The area of Spartina would be rated a Category II while the relatively undisturbed upper marsh with native species would be a Category I. Do not, however, exclude the area of Spartina in· determining the size threshold of 1 acre. -At least'/., of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Wetland Rating Form -western Washington version 2 18 August 2004 Cat. I Cat. I Cat. II Dual rating I/II Wetland name or number SC 2.0 Natural Heritage Wetlands (seep. 87) Natural Heritage wetlands have been identified by the Washington Natural Heritage Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2.1 Is the wetland unit being rated in a Section/Township/Range that contains a Natural Heritage wetland? !J!:'s quesllon is used to screen out most s,te., before you need to comac:;r,,~HPIDNR) Sff/R information from Appendix D _ or accessed from WNHP/DNR web site _ YES __ -contact WNHP/DNR (seep. 79) and go to SC 2.2 NO SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as or as a site with state threatened or endangered plant species-z/ YES ~ Category I NO . .,/ not a Heritage Wetland SC 3.0 Bogs (seep. 87) Does the wetland unit (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below lo identify if the wetland is a bog. If you answer yes you will still need to rate the wetland based on its functions. 1. Does the unit have organic soil horizons (i.e. layers of organic soil), either peats or mucks, that compose 16 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes - go to Q. 3 No -go to Q. 2 2. Does the unit have organic soils, either peats or mucks that are less than 16 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? Yes -go to Q. 3 No -ls not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? Yes -Is a bog for purpose of rating No -go to Q. 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. 1. Is the unit forested (> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine, WITH any of the species ( or combination of species) on the bog species plant list in;;~ 3 as a significant component of the ground cover(> 30% coverage of/Ltotal shrub/herbaceous cover)? 2. YES = Category l No_ Is not a bog for purpose ofrating Wetland Rating Form -western Washington version 2 19 August 2004 Cat. I ·-.·.:·,, .. Cat. I Wetland name or number ·· .... SC 4.0 Forested Wetlands (seep. 90) Does the wetland unit have at least I acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats? If you answer yes you will still need to rate the wetland based on its functions. -Old-growth forests: (west of Cascade crest) Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height (dbh) of32 inches (81 cm) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. -Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80 -200 years old OR have average diameters (dbh) exceeding 21 inches (53cm); crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity oflarge downed material is generally less than that found in old-growth. L. YES ~ Category I NO not a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (seep. 91) Does the wetland meet all of the following criteria ofa wetland in a coastal lagoon? -The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks -The lagoon in which the wetland is located contains surface water that is saline or brackish(> 0.5 ppt) during ;os ,of the year in at least a portion of the lagoon (needs to be measured r the bottom) YES= Go to SC 5.1 NO_· not a wetland in a coastal lagoon SC 5.1 Does the wetland meets all of the following three conditions? -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). -At least 'I, of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland is larger than 1/10 acre (4350 square feet) YES = Category I NO = Category II Wetland Rating Form-western Washington version 2 20 August 2004 " -, · .. --,.· ·._ Cat. I Cat. I Cat. II \Vctland name or number SC 6.0 Interdunal Wetlands (seep. 93) Is the wetland unit west of the 1889 line (also cazle the Western Boundary of Upland Ownership or WBUO)? YES -go to SC 6.1 NO.....:_ not an interdunal wetland for rating If you answer yes you will still need to rate the wetland based on its functions. In practical terms that means the following geographic areas: • Long Beach Peninsula-lands west of SR I 03 • Grayland-Westport-lands west of SR 105 • Ocean Shores-Copalis-lands west of SR 115 and SR 109 SC 6.1 ls the wetland one acre or larger, or is it in a mosaic of wetlands that is once acre or larger? YES = Category II NO -go to SC 6.2 Cat. II SC 6.2 ls the unit between 0.1 and I acre, or is it in a mosaic of wetlands that is between 0.1 and I acre? YES = Category III Wetland Rating Fonn-western Washington version 2 21 August 2004 Cat. III ATTACHMENT B Mitigation Reserve Program Fee-In-Lieu Worksheets ® Mitigation Reserves Program Fee-In-Lieu Worksheet Cavalla DOES Permit# King County Date· 5/10/2007 Preoared bv; Chad Armour, LLC PLANT MATERIALS' Type Unit Price Unit Quantity Description Cost PLANTS Potted, 4' diameter, medium $5.00 Each 12.0 $ 60.00 PLANTS: Container. 1 gallon, medium soil $11.51 Each 12.0( $ 138.00 PLANTS. Container, 2 gallon, medium soil $20.00 Each 12.0 $ 240.00 PLANTS: Container, 5 gallon, medium soil $36.0( Each $ PLANTS Seeding, by hand $0.5 SY 49.00 444 sf $ 24.50 PLANTS Sips (willow, red-osier) $2.00 Each $ - PLANTS Slakes (willow) $2.00 Each $ • All costs include installation TOTAL $ 462.50 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Untt Price Unit Cost Compos!, vegetable, delivered and spread $37.88 CY 3.00 3 ft rad around ea plant: 3 in dee $ 113.64 Decompacting lilVhardpan, medium. lo 6' depth $1.57 CY $ - Decompacting ii!Vhardpan, medium, to 12' depth $1.57 CY $ - Fertilize, slow release tablets, 30gm/tree $3.21 Each $ - Hydrnseeding $0.51 SY 49.0( 444 sf $ 24.99 Labor, general(landswiping) $25.N HR $ - labor, general (conslrucfon) $37.00 HR 16.0 887 sf (0.02 ac) $ 592.00 Labor· Consuftant supervising $55.0C HR 10.00 887 sf (0.02 ac) $ 550.00 Labor: Consuftant. on-site re-design $95.0 HR $ - Rental of decompacting machinery & operalor $70.65 HR $ - Sand, coarse builder's, delivered and spread $42.06 CY $ - Staking material (set per tree) $7.00 Each 12.00 $ 84.00 Surveying, line & grade $250.0( HR $ - Surveying, topographical $250.D< HR 8.00 $ 2,000.00 Watering, 1' of water, 50' soaker hose $3.62 MSF $ - !rrigalion -temporary $3,000.0 Acre $ - Irrigation -buried $4,500.0( Acre 0.02 $ 90.00 Tilling lopsol, disk harrow. 20hp tractor, 4"-6" deep $1.02 SY $ - TOTAL $ 3,454.63 HABITAT STRUCTURES' ITEMS Unit Cost Unit Cost Fascmes ('Mllow) $ 2.00 Each $ logs, (cedar}, W 10ot wads, 16"-24" dam. 30' long $1,000.01 Each 1.00 $ 1.000.00 Logs (cedar) 'Mo root wads, 16'-24" darn JO' $400.01 Each $ - Logs, w/o root wads. 16" -24' dam., 30' long $245.01 Each $ - Logs w/ root wads, 16' -24' diam., 30' long $460.D< Each $ Rocks, one-man $60.00 Each $ - Rocks, two-man $120.0• Each $ - Rool\Wds $163.0( Each $ Spawning gravel, type A $22.<> CY $ - Weir -log $1,500.01 Each $ - We¥ -adjustable $2,000.0 Each $ - Woody debris, large $163.01 Each $ - Snags -anchored $400.0( Each 1.00 $ 400.00 Snags -on sile $50.00 Each $ . Snags -imported $800.0 Each $ - • All costs include delivery TOTAL $ 1,400.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backfill and Compact1on--i!mbankment $ 4.89 CY $ Crushed surfacing, 1114'minus $30.00 CY $ - Drtchmg $7.03 CY $ - Excavation, bulk $4.00 CY $ - Fence, s111 $1.60 LF 30.00 887 sf (0.02 ac) $ 48.00 Jute Mesh $1.26 SY $ - Muli;h, by hand, straw, 2' deep $1.27 SY $ - Mulch, by hand. mod chips. 2' deep $3.25 SY $ - Mulch. by machine, s1raw, 1' deep $0.32 SY $ - Piping, temporary, CPP, 6' $9.30 LF $ - Piping, temporary. CPP, 8' $14.00 LF $ Piping, temporary, CPP, 12' $18.00 LF $ - PJaslic coVBring, 6mm thick, sandbagged $2.00 SY $ Rip Rap, machine placed, slopes $33.98 CY $ Rock Constr. Entrance 100'x15'x1' $3,000.00 Each $ - Rock Conslr. Entrance 50'x15'xl' $1,500.00 Each 0.33 887 sf (0.02 ac) $ 495.00 Sedimen1 pond riser assembly $1,695.11 Each $ Sedimen1 trap, 5' hjgh berm $15.5" LF $ Sediment trap, 5' high berm w/spHlway tncl. riprap $59.6[ LF $ - Sodding, 1'deep, levelgrourid $5.24 SY $ - Sodding, 1' deep, sloped ground $6.48 SY $ - Straw bales, place and remove $600.0 TON $ - Hauling and disposal $20.0 CY $ - Tops oil, de!vered and spread $35.73 CY $ - lrnrAL $ 543.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain link. 6' high $18.8! LF $ Fencmg, cham link, corner pos1s $111.1, Each $ Fencmg, chain link. gate $277.6' Each $ Fencing, splrt rail. 3' high (2-rail) $10.5 LF 30.00 887 sf (0.02 ac) $ 316.20 Fencing, lemporary (NGPE) $1.20 LF $ Signs. sensrtrvearea bouridary $2.5[ Each 1.00 $ 2.50 lroTAL $ 318.70 OTHER ITEMS MAINTENANCE AND MONTIORING Mam1enance and Monrtormg lnspectron, annual Maintenance and Monrtoring lnspecl1on, final LAND COSTS LONG TERM SITE MANAGEMENT MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS Percentage of Construction Cost Unit (Consfruction Cost Subfo(al) TOTAL NOTE: Projects with multiple permit requirements may be required to have longer monitonng and maintenance tem:s. This will be evaluated on a case-by- case basis for development applications. Monitoring and rnaintance ranges may be assessed anywhere from:.,:,,5;:to;:,;10:;.+ye,',:;';'·-,----,=~.,-=-,,,,-=c EACH $144.9 EACH 4 ·00 $144.90/hr Unit Cost Unit Quantity Description $ 56,000.00 Acre 0.02 Unit Cost Unit Quantity Number of years $ 85.00 Acre 1 20 Total $ 6,17B.B3 Cost $ 5,560.95 2,160.00 2,880.00 $ 289.80 $ 579.60 $ 5,909,40 Cost $ 1,120.00 $ 1,700.00 $20,469.18 CHAD ARMOUR, LLC May 16, 2007 Mr. Curtis Schuster KBS Develo~ment Corporation 12320 NE 81 Street, Suite 100 Bellevue, Washington 98005 Subject: Conceptual Wet(and Mitigation Plan 162"d Avenue SE -Proposed Extension King County, Washington Dear Mr. Schuster: 6500 126"' Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com The following plan presents our approach to mitigating for unavoidable impacts to the buffer of Type 3 streams. We first looked for the opportunity to make up lost area on the site. Then, assuming that off-site mitigation is necessary and possible, we estimated the cost to rehabilitate an off-site degraded buffer. PROPOSED DEVELOPMENT PLAN Three different plats, Cavalla, Liberty Gardens, & Threadgill, are soon to be the location of single-family homes (Figure 1 ). Access to these plats is primitive or non-existent and will need to be constructed and upgraded. The preferred alternative to access these three sites is to construct a half a road (162"d Avenue SE) extending north from SE 144th Street. This road will be about 625 feet (ft) long and connect with the soon to be constructed 162"d Avenue SE along the western boundary of the Liberty Gardens Preliminary Plat (Figure 2). The road extension project for the three development proposals is being managed by KBS Development Corporation (Proponent). We understand that the streams associated with the 162"d Avenue SE extension is subject to the sensitive areas ordinance. We also understand that because there is not enough area available on site to make up for unavoidable impacts, additional mitigation will use the Mitigation Reserves Program. MAIN FILE COPY EXISTING CONDITIONS A Type 3 stream flows down the 162"d Avenue SE Right of Way (Figure 2 -Primary Type 3 Stream). The drainage originates north and west of the Right of Way (ROW). It is alternately located in a roadside ditch and buried culvert adjacent to 158th Avenue SE, SE 136th Street, and 160th Avenue SE before it is discharged to the Smith property (Parcel No. 145750-0110). After flowing across the Smith property initially as sheet flow and then in a culverUditch system, it is discharged to an "engineered" ravine adjacent to Rich Lea Crest. Here the walls of the stream are short and steep and lined with quarry spalls. The stream turns south when it meets the 162"d Avenue SE ROW and flows through a deep narrow ravine. The stream discharges to an engineered (i.e., constructed) stormwater detention pond that is connected to an underground stormwater conveyance system that presumably dischar ef.:19-l~TI ~· @ U 'Y!J 15 AIN FILE COPY_ / ,,, 1 C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.do Chad Armour, LLC 1 os,16101 {!JS fUCd'u Jt;L O 2 2007 K,C o.o.E.S 162nd Avenue SE Extension Mitigation Plan King County, Washington KBS Development Another Type 3 stream (Secondary Type 3 Stream) flows into the northern or upper end of the storm water retention pond. This stream crosses Liberty Gardens and a cleared area to the south before joining the Primary Type 3 stream. Stream Buffer The plant communities in the 162nd Avenue SE ROW adjacent to the stream include immature forest, a thick tangle of blackberry shrubs, and mowed grass. The buffer adjacent to the stormwater pond along the lower -250 ft of the ROW generally supports grass and a few Douglas-fir (Pseudotsuga menziesi1) trees. From the pond's eastern slopes and a point about -100 ft to the east the plant community includes a few deciduous trees growing through dense Himalayan blackberry (Rubus discolor) shrubs. The upper or northern -300 ft of the ROW is the location of an immature forest composed of big-leaf maple (Acer macrophy/Jum), Douglas-fir, black cottonwood (Popu/us balsamifera), and red alder (A/nus rubra) trees growing among a thick tangle of shrubs, including blackberries. In one location the back of a home and associated out building in Rich Lea Crest are located within a few feet of the west bank of the Primary Type 3 Stream. · CONCEPTUAL MITIGATION PLAN The plan is to: • Straighten the Primary Type 3 Stream; • Route the Secondary Type 3 Stream through a culvert; • Enhance the remaining available buffer following road construction; and • Pay the County a fee to enhance buffer off of the site. CONSTRUCTION PLAN The site is too small to accommodate mitigation entirely on the site. As such, the plan is to enhance as much of the degraded on-site buffer as possible (-15,000 square feet [sf]) and pay the County the equivalent fee to mitigate for buffer impacts that cannot be achieved on the ROW by enhancing 14,500 sf of degraded off-site buffer (Table 1 ). On-Site Buffer Enhancement We assume that machine encroachment will be limited to trackhoe excavators used to install snags and place logs. We also assume that most if not all of the crushed shrubs and herbs will naturally recover. We further assume that: • The blackberry shrubs will be removed to expose bare mineral soil and prepare the area for planting; • A total of 71 conifer and 54 deciduous trees will be installed individually 11 ft on center (QC) to increase tree density (Table 2); • A total of 490 shrubs will be installed in clumps 5 ft OC to promote a robust native shrub layer; • The ground will be covered (2'80%) with at least three different native herbaceous plant species; and • A total of 2 snags and 2 logs will be installed. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc 2 05/16/07 Chad Armour, LLC 00 :,-:..:.. Cl c... o.o )> g- 3 W oO E; I:!! ·o ::: " 0~ \ fg '5 t: "' C: r- i ~ ,,. ijj .... ~ ~ Table 2 -Plant and Habitat Amenity Installation Guide On-Site Buffer Off-Site Buffer 27 (6-8 ft; 11 ft oc 27 (6-8 ft; 11 ft oc 71 36 (6-8 ft; 11 ft oc 70 35 (6-8 ft; 11 ft oc 245 125 193 193 Comus stolonifera 193 Ma/us fusca 193 965 2 • 15,000 sf; to be enhanced on-site b 14.500 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve c total average density is 0.041 plants/sf A~ -· 0) ::, ~ "' ~ () ;t> 0 < C (1) :, ::, .:;z C: . "' ~ (/) a, m lg. m -·x <5 ar 0~ => er :, ~ I '1J ii> :, ;,; OJ (/J i s -0 ~ ,.. 162"a Avenue SE Extension Mitigation Plan King County, Washington KBS Development It should be noted that mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this mitigation plan is the responsibility of the permitting authority. Accordingly, the mitigation plan developed for this road extension should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC ~ A"·rt- Chad Armour Principal Attachments: Table 1 -Buffer impact and makeup areas Table 2 -Plant and Habitat Amenity Installation Guide Figure 1 -Vicinity Map Figure 2 -Site Plan Attachment A -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County DDES C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 6 05/16/07 FIGURES Ren_!f( i---~l-----l:llt&ll:L-11 ~ . ..ffllll!M;fi DN TRAFFIC CONSULTANTS VICINITY MAP FIGURE 1 PLAT OF THREADGILL CAVALLA LIBERTY GARDENS Liberty Gf)rdens ! I i I.. I I / / / //-1 I I _ _;_ » / - I/,,- / / - /// / / "· / /,// / .// // // //; /"/ / . . ///r-·· ~ /·· // ./ I __ ,.-}/ ·// 1~· ~k,,Nt . I I/ . -lfoo1 BRIDGE I I/. ,:: /" j I I I I l ·/·-~--=-~-----------~ ·/ / .. / / ' ' ' l J • i j 1 ( I .. /.. \ . . "°i'ffll'l"l''"' 1""1,-r:rei "'°o '' ' .. .. . . ....... --- \ : __ !:!,0~'23'36.'.:_E _491,,2_7~ _ _L,~ ___ :-;"' ___ -:.:. <-""-25"Fun~ :161ND A~SE 1(C I ---; ... -··-, +·· ... ·, ... ~ " .;:.[:~ -· · ~ ·· -: 25' Buffer fi1 · · .-~. ------r--------I , I . --" ' 1 .•.. ----r--- I I . " I I Smith Property ,u 1=1n; : I i ! \ . \ t \ _J J Primary Type 3 Streilm I I I I I I l ,, -~'' ~-~ N.---.._..._ 0 60 Scale in Feet 120 .. Rich Lea Crest -- r Secondary Type 3 Stream ----/ !-·--l """·'\" ' ' " --' \\ \ \ 1_ _ \ ' \ \ FIGURE 2: SITE PLAN 162nd Avenue SE Extension King County, Washington / to 'i!: ·.· ~ ~ w (J) Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 ® Mitigation Reserves Program Fee-In-Lieu Worksheet DOES Permrt#· Multiple King County Date: 5/10//2007 Preoared bv: Chad Armour, LLC PLANT MATERIALS' Type Unit Price Unit Quantity Description Cost PLANTS: Potted, 4' diameter, medium $5.00 Each 198.01 $ 990.00 PLANTS: Container, 1 gallon, medium sail $11.5 Each 198.0C $ 2,277.00 PLANTS. Container, 2 gallon, medium soil $20.00 Each 199.0( $ 3,980.00 PLANTS: Container, 5 gallon, medium soil $36.0 Each $ - PLANTS: Seeding, by hand $0.5 SY 806.00 7,250 sf $ 403.00 PLANTS: Sl~s (willow, red-osier) $2.0 Each $ - PLANTS: Stakes (wiffow) $2.00 Each $ - • All costs include installation . TOTAL $ 7,650.00 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unit Price Unit Cost Compost, vege1able, delivered and spread $37.88 CY 39.0( 3 ft rad around ea r:lant: 3 in dee $ 1,477.32 Oecompacting tilVhardpan, medium, to 6' depth $1.57 CY $ - Oecompacting t~Vharct,an, mecium, to 12' dep1h $1.57 CY $ - Fertilize, slow release tablets, 3Dgmltree $3.21 Each $ - Hyctoseeding $0.51 SY 806.00 7,250 sf $ 411.06 Labor, general (landscapmg) $25.0 HR $ - labor, general jconstruclkln) $37.oo HR 16.00 14,500 sf (0.33 ac) $ 592.00 labor: Consuttant supeJ"'.'isinn $55.00 HR 10.00 14,500 sf (0.33 ac) $ 550.00 Labor: Consultant, on-sile re-design $95.00 HR $ - Rental of decornpacting machinery & operator $70.65 HR $ - Sand, coarse builder's, delivered and spread $42.06 CY $ Staking material (set per tlee) $7.00 Each $ SuJ"\'eying, line & grade $250.0 HR $ - Surveying, topographical $250.00 HR 8.00 $ 2,000.00 Waiering, 1' oi water, 50' soaker hose $3.62 MSF $ - Irrigation -temporary $3,000.!JU Acre $ - Irrigation -buned $4,500.0 Acre 0.33 $ 1,485.00 Tiling topsoi, cisk harrow, 201lp tractor, 4'-6" deep $1.02 SY $ - TOTAL $ 6,515,38 HABIT AT STRUCTURES• ITEMS Unit Cost Unit Cost Fascines (wilow) $ 2.00 Each $ - Logs, (ceder), wl root wads, 16"-24' diam., 30' long $1,000.'" Each 3,00 $ 3,000.00 Logs !cedar) Worootwads, 16'·24' Oam., 30' $400.0 Each 8.00 $ 3,200.00 Logs, Worootwads, 16'-24' diam., 30' long $245.0I Each $ - Logs wt root wads, 16"-24' diam, 30' Jong $460.0 Each $ - Rocks, one-man $60.00 Each $ Rocks. two-man $120.01 Each $ Roo1 wads $163.0 Each $ - Spawning gravel, type A $22.V CY $ Weir-log $1,500.rn Each $ - Weir -adjustable $2,000.0C Each $ - Woody debris, large $163.0 Each $ - Snags -anchoced $400.0( Each 15.00 $ 6,000.00 Snags -on s~e $50.0 Each $ - Snags -impelled $800.0 Each $ - • All costs include delNery TOTAL $ 12,200.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backfill and Compaction-embankment $ 4.89 CY $ - Crushed surfacing, 1 114' minus $30.0 CY $ D~ching $7.0 CY $ - Excavation, bulk $4.00 CY $ Fence, siH $1.6 LF 120.00 14,500 sf (0.33 ac) $ 192.00 Jute Mesh $1.26 SY $ - Mulch, by hand, straw, 2'deep H2 SY $ - Mulch, by hand, wood chips, 2' deep $3.25 SY $ - Mulch, by machine, straw, 1' deep $0.32 SY $ - Piping, temporary, CPP, 6' $9.31 LF $ - Pipmg, temporary, CPP, a· $14!" LF $ - Piping, temporary, CPP. 12' $18.0I LF $ - Plaslic covering, 6mm thic:k, sandbagged $2.00 SY $ - RP Rap, machine placed,sl:lpes $33.91 CY $ - Rock Constr. Entrance 100'x15'x1' $3,000.00 Each $ - Rock Constr. Entrance 50'x15'x1' $1,500.00 Each 0.66 14,500 st (0.33 ac) $ 990.00 Sediment pond riser assembly $1,695.11 Each $ - Sediment trap, 5' high berm $15.5 LF $ - Sedimenl lrap, 5' high berm w/spillway incl. riptap $59.6( LF $ - Sodding, 1' deep, level graund $5.2• SY $ - Sodding, 1' deep, sloped ground $6.41 SY $ - Straw bales, place and remove $600.0C TON $ - Hau~ng and disposal $20.00 CY $ - Topso~. delivered and spread $35.73 CY $ - fro?AL $ 1,182.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain fink. 6' high $18.8 LF $ - Fencing, chain ink, comer posts $111.1 Each $ - Fencing, chain tink, ga1e $277.6' Each $ - Fencing, spit rail, 3' high (2-rail) $10.5 LF 120.0C 14,500 sf (0.33 ac) $ 1,264.80 Fencing. temporary (NGPE) $1.2C LF $ - Signs, sensttive area boundary $2.SC Each 1.00 $ 2.50 lroTAL $ 1,267.30 OTHER ITEMS MAINTENANCE AND MONTIORING Mainten,:ince and Monitoring Inspection, annual Maintenance and Mon~oring /nspoc1ion, final LAND COSTS $ LONG TERM SITE MANAGEMENT $ MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS Percentage of Construction Cost (Construction Cost Subtotal) TOTAL NOTE: Projects with multiple permit requirements may be required to have longer monitoring and maintenance terms. This will be evaluated on a case-by- case. basis for development applications. Monitoring and mamtance ranges may be assessed anywhere from 5 to 10 years. EACH 2 ·50 $144.90/hr EACH 4 .oo $144.90/hr TOTAL Unit Cost Unit Quantity Description 56,000.00 Acre 0.333 Unit Cost Unit Quantity Number of years 85.00 Acre 1 20 $ 28,814.68 $ 40,340.55 4,320.00 2,880.00 $ 362.25 $ 579.60 $ 8,141.85 ' ' 'ii?: Cost $ 18,648.00 $ 1,700.00 ~----------., Total $97,645.08 CHAD ARMOUR, LLC May 16, 2007 Mr. Dave Petrie 811 South 273"' Court De Moines, Washington 98198 6500 126"' Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com Subject: Conceptual Wetland Mitigation Plan (revised) Liberty Gardens Preliminary Plat (L04P0034) King County, Washington Dear Mr. Petrie: We revised our conceptual mitigation plan based on information provided to us by Mr. Nick Gillen in the meeting we had on February 28, 2007 and the fee-in-lieu spreadsheet on March 14, 2007. As you will recall, we chose the fee-in-lieu option to mitigate for unavoidable impacts to wetlands because the area available on the site for mitigation is the location of a mature forest. The following describes our approach in revising the conceptual mitigation plan including the estimated cost to construct a wetland off of the site. PROPOSED DEVELOPMENT PLAN Mr. Dave Petrie (Proponent) proposes to construct 37 single-family homes on the 8.95- acre Liberty Garden site (see Preliminary Plat of Liberty Gardens). To do so, it will be necessary to construct new roads and storm management facilities (see Preliminary Grading and Storm Drainage Plan of Liberty Gardens). The road will impact a total of 2,387 square feet (sf) of Class 2 wetland and 14,840 sf of buffer (Table 1 and Preliminary Plat of Liberty Gardens). It will also impact an intermittent stream that flows through one of the wetlands and across the site. We understand that the planned development is vested under the King County Sensitive Areas regulations. CONCEPTUAL MITIGATION PLAN The proposed mitigation plan is to: • • • • • • • Protect a portion of the wetland associated with the intermittent stream; Protect the intermittent stream; MAIN FILE COPY Protect the associated buffer; Fill a portion of two wetlands and associated buffer; Increase the width of buffer adjacent to wetland adjacent to the stream to make up for lost buffer; Enhance the buffer makeup areas; and fcj) rn © rn O w @: fo'\ Pay the County a fee to create a 7,161 sf wetland off of the siJJu JGL O 2 2:J? ~} K.C. D.D.E.S C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 1 Chad Armour, LLC MAIN FILE COPY 05/16/07 ljJt, fb'1' tJ I Liberty Garden Revised Mitigation Plan King County, Washington act and makeu areas• • based on Preliminary Grading Plan (revised) of Liberty Gardens b 961sf + 1,426 sf ' to be made up according to KKC 21A.24.137 Resource Mitigation Reserve ' 8,379sf + 6,207sf+ 254sf EXISTING CONDITIONS Mr. Dave Petrie According to B-12 Wetland Consulting (2004) and our observations over the last several years, the upland forest is composed of an overstory of mature big-leaf maple (Acer macrophyllum), red alder (A/nus rubra), western red cedar (Thuja p/icata), Douglas-fir (Pseudotsuga menziesil), and western hemlock (Tsuga heterophylla). The understory supports salmonberry (Rubus spectabilis), Indian plum (Oemleria cerasiformis), hazel nut (Cory/us comuta), sword fern (Po/ystichum munitum), salal (Gaultheria shallon), and bracken (Pteridium aquilinum). Wetland AIB (Southern Wetland) The southern wetland is a Class 2 wetland that consists of a narrow strip of forest adjacent to a Class 3 intermittent stream (B-12 Wetland Consulting, 2004). The wetland supports an overstory of red alder and black cottonwood (Populus balsamifera) trees. The understory supports salmonberry, lady fern (Athyrium filix-femina), and tall mannagrass (Glyceria e/ata). Wetland C (Northern Wetland) The northern wetland is a Class 2 wetland dominated by immature red alder trees, salmonberry shrubs, and lady fern (B-12 Wetland Consulting, 2004). Mature Trees In the Reduction and Makeup Areas As indicated on Table 2 and the Significant Tree Retention Plan of Liberty Gardens, 20 medium-to large-sized deciduous and conifer trees will be lost due to the proposed development. To offset this loss, a total of 21 medium-to large-sized deciduous and conifer trees will be protected in buffer makeup areas. C:/Jobs/BCE/Petrie/Fee In-lieu Letter(revised).doc 2 Chad Armour, LLC 05/16107 Liberty Garden Revised Mitigation Plan King County, Washington • see Significant Tree Retention Plan for details CONSTRUCTION PLAN Mr. Dave Petrie We developed this plan to mitigate for lost wetland and buffer area and functions by assuming that a 7,161 sf wetland will be created off of the site and 14,840 sf buffer will be enhanced on the site. We used the general guidance for completing fee-in-lieu worksheet for offsite mitigation construction costs (Attachment A) to determine the materials and labor to construct a wetland (King County, Undated). Table 3 illustrates the suggested plants and habitat amenities to be installed in the created wetland and enhanced buffer. Off-Site Wetland Creation We assume that: • It will be necessary to purchase urban land; • A total of 92 trees and 205 shrubs will be installed in the created wetland at a rate of 0.041 plants/sf (Table 3); • A mixture of native herbaceous plant species will be broadcast seeded on the wetland creation area; • 9 snags and 6 logs will be installed in the wetland creation area; and • It will take 4 hours to deconsolidate the soil, compost will be added around each of the installed plants in a circle 3 feet (ft) in diameter and 3 inches (in) deep, and the site will be irrigated by way of a permanent irrigation system (Attachment A). On-Site Buffer Enhancement In the buffer enhancement areas, we assume that machine encroachment will be limited to trackhoe excavators used to install snags and place logs. We assume that the crushed shrubs and herbs will recover. We also assume that: • A total of 38 western red cedar trees will be installed 20 ft on center to increase the density of conifer trees in the buffer make up areas; C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 3 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington Mr. Dave Petrie Table 3 -Plant and Habitat Amenit Installation Guide Quantit Total Wetland Buffer western red cedar Thu·a licata various 0.041 I/sf 92 92 0 western red cedar Thu'a licata various 20 ft oc 38 0 38 Total Trees 130 92 38 ' (. ' . 1 ' ---~-· -__ ..,::; __ ~----··~ -----~ black twinber clustered rose Pacific ninebark red-osier do wood western craba le Total Shrubs great beton large-leaved avens tall manna tufted hair rass Sna s Los Lonicera invo/ucrata Rosa Cornus stolonifera Ma/us fusca randiflora Stachys coo/e i Geum macro h I/um Deschampsia ces itosa Oenanthe various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf seed broadcast seed broadcast seed broadcast seed broadcast seed broadcast 16" to 24" dbh; 30' Ion 16" to 24" dbh; 30' Ion 41 41 0 41 41 0 41 41 0 41 41 0 41 41 0 205 205 0 X X X X X X X X X X 28 9 19 21 6 15 • 7,161 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve ' 15,004 sf; to be made up and enhanced on-site C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 4 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington Mr. Dave Petrie • It will not be necessary to install shrubs and herbs because a dense layer of shrubs and a robust assemblage of herbs are present in the buffer enhancement areas; • 19 snags and 15 logs will be installed; • The snags and logs will come from trees harvested on the site: • A signed split-rail fence will protect the Southern Wetland, the intermittent stream, and associated buffers. MONITORING The Proponent will monitor the on-site mitigation areas for at least three years following installation in the summer. The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for monitoring the off-site wetland for at least three years following installation. The "fee-in-lieu' revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for monitoring associated with the proposed wetland fill and subsequent mitigation efforts. MAINTENANCE The Proponent will maintain on-site mitigation area as follows: • Remove weeds for three years after installation. Weeds include non-native vegetation, particularly Himalayan blackberry, reed canarygrass, and evergreen blackberry; and • Replace trees that die during the 3-year monitoring program to maintain the minimum 80 percent survival rate. The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for maintenance of the off-site wetland during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for maintenance associated with the proposed wetland fill and subsequent mitigation efforts. CONTINGENCY PLAN If there is difficulty achieving the performance standards on the site, the Proponent proposes to work with the County to develop a contingency plan. Contingency plans can include, but are not limited to: additional plant installation and plant substitutions of type, size, quantity, and location. Such a contingency plan shall be submitted to the County by December 1 '1 of any year when deficiencies are discovered. The Proponent has included costs in the Mitigation Reserves Program "Fee-In-Lieu Worksheet" to allow for a contingency plan should deficiencies in the off-site wetland be discovered during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for contingency measures associated with the proposed wetland fill and subsequent mitigation efforts. C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 5 Chad Armour, LLC 05116107 Liberty Garden Revised Mitigation Plan King County, Washington SCHEDULE Mr. Dave Petrie The Proponent anticipates executing this plan at the first available opportunity following the receipt of the necessary approvals from the County. Assuming construction occurs the summer of 2007, the first monitoring event will occur the following spring. The Proponent will submit a monitoring report as indicated previously. Maintenance will occur within four months following submission of the monitoring report. Subsequent monitoring, reporting, and maintenance will follow the same schedule during the subsequent years. LIMITATIONS Work for this project was performed, and this mitigation plan prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of Mr. Dave Petrie and his assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that wetland mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this wetland mitigation plan is the responsibility of the permitting authority. Accordingly, the wetland mitigation plan developed for this plat should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. REFERENCES 8-12 Wetland Consulting, Inc. 2004. Liberty Gardens Critical Areas Analysis Area Report & Conceptual Mitigation Plan, King County WA. Prepared for Mr. Dave Petrie, 811 S. 273'd Ct., Des Moines, WA 98198. King County. Undated. Mitigation Reserves Program, Fee-In-Lieu Worksheet. C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 6 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington Mr. Dave Petrie Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC CU.fl~ Chad Armour Principal Attachments: Figure 1 -Vicinity Map Figure -Preliminary Plat Map of Liberty Gardens Figure -Preliminary Grading and Storm Drainage Plan of Liberty Gardens Figure -Significant Tree Retention Plan of Liberty Gardens Attachment A-Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County ODES C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 7 Chad Armour, LLC 05/16/07 FIGURES ON TRAFFIC CONSULT ANTS VICINITY MAP FIGURE 1 ' I PLAT OF THREADGILL CAVALLA LIBERTY GARDENS ATIACHMENTA Mitigation Reserve Program Fee-In-Lieu Worksheets ® Mitigation Reserves Program Fee-In-Lieu Worksheet ODES Permit# L04P0034 King County Date· 5/16/2007 Preoared bv: Chad Armour, LLC PLANT MATERIALS" Type Unit Price Unit Quantity Description Cost PLANTS: Potted, 4' diameter, medium $5.00 Each $ PLANTS: Container, 1 gallon, medium soil $11.5C Each 74.00 $ 851.00 PLANTS: Container, 2 gallon, medium soil $20.00 Each 74.00 $ 1,480.00 PLANTS· Container. 5 gallon. medium soil $36.00 Each 74.00 $ 2,664.00 PLANTS: Seeding, by hand $0.50 SY 795.00 7,161 sf $ 397.50 PLANTS: S!l)s (willow, red-osier) $2.00 Each 74.00 $ 148.00 PLANTS· Stakes (willow} $2.0 Each $ • All costs includti instaUalion TOTAL $ 5,640.60 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unit Price Unit Cost Compost. vegetable, deliYered and SJ:fBad $37.88 CY 20.00 3 ft rad around ea plant; 3 in dee $ 757.60 Decompacling lilVhardpan, medium, lo 6' depth $1.57 CY 150.00 $ 235.50 Decompaciing HVhardpan, medium, lo 12' depth $1.57 CY $ - Fertilize, slow release lablels, 30gm/lree $3.21 Each $ Hyctoseedilg $0.51 SY 0.00 hand seeded $ Labor, general (landscap111g) $25.00 HR $ . labor, general (construction) $37.00 HR 16.00 7,161 sf (0.16 ac) $ 592.00 labor: ConsuHant. supervising $55.0 HR 10.0C 7,161 sf (0.16 ac) $ 550.00 Labor: ConsuHant, on-sije re-design $95Jll HR $ . Rental of decompac\ing machinery & operator $70.65 HR 6.00 assumed $ 423.90 Sand, coarse builde~s. delivered and spread $42.06 CY $ . Staking material (set per tree) $7.00 Each 92.0 $ 644.00 Surveying, line & grade $250.0 HR $ Surveying, topographical $250.0t HR 8.00 $ 2,000.00 Watering, 1' of water. 50' soaker hose $3.62 MSF $ lrriga1ion -temporary $3,000.0( Acre $ Irrigation -buried $4,500.0I Acre 0.16 $ 720.00 T.iling topsoi, dsl< harrow, 20hp tractor, 4'-6' deep 795.00 7,161 sf; strip & stockpile topsoil $1.02 SY and then reapply $ 810.90 TOTAL $ 6,733.90 HABITAT STRUCTURES' ITEMS Unit Cost Unit Cost Fascines (wifow) $ 2.00 Each $ Logs, (cedar), W rool wads, 16' -24' dam., 30' long $1,000.0C Each 3.00 $ 3,000.00 Logs /cedar) Wo root wads. 16'-24' ciam., 30' $400.0 Each 3.00 $ 1,200.00 Logs, Wo roolwads, 16'-24' diam., 30' long $245.0( Each $ Logs w/ root wads. 16'-24' dam., 30' long $460.0C Each $ Rocks, one-man $60.00 Each $ - Rocks, two-man $120.0{ Each $ . Roo1wads $163.0C Each $ . Spawning gravel, type A $22.00 CY $ . Weir-tog $1,500.DC Each $ . Weir • adjus1able $2,000.(ll Each $ Woody debris, large $163.0C Each $ . Snags -anchind $400.0C Each 9.00 $ 3,600.00 Snags -on site $50.00 Each $ - Snags -11T1ported $BOO.DO Each $ - • All costs include de/Nery TOTAL $ 7,800.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backf~land Compaction-embankmen1 $ 4.89 CY $ Crushed surfacing, 1114' minus $30.0( CY $ . Dfohrig $7.0 CY $ . Excavation, bulk $4.0 CY $ . Fence. sill $1.60 LF 85.0 $ 136.00 Jute Mesh $1.26 SY $ Mulch, by hand, straw, 2' deep $1.2 SY $ . Mulch, by hand, 'oVOod chips, 2' deep $3.25 SY $ . Mulch, by machine, straw, 1' deep $0.32 SY $ . Piping, lemporary, CPP, 6' $9.30 LF $ . Pipmg, temporary, CPP, 8' $14.00 LF $ Piping, temporary, CPP, 12' $18.00 LF $ . Plastic covering, 6mm !hick, sandbagged $2.0 SY $ . Rip Rap, machine placed, slopes $33.98 CY $ . Rock Constr. Entrance 1DO'x15':d' $3,000.00 Each $ . Rock Constr. Entrance 50'x15'x1' $1,500.00 Each 0.33 7,161 sf (0.16 ac) $ 495.00 Sediment pond riser assembly $1,695.11 Each $ . Sediment trap, 5' h{lh berm $15.57 LF $ . seamenl rap, 5' high berm Wlspilway inci. riprap $59.60 LF $ . Sodding, 1' deep, level ground $5.24 SY $ . Soddrlg, 1' deep, sloped ground $6.4 SY $ . Straw bales, place and remove $600,0 TON $ . Hauling and disposal $20.00 CY $ . Topsoil, delivered and spread $35.73 CY $ . I TOTAL $ 631.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain ink, 6' high $18.8 LF $ . Fencing, chain ~nk, comer pos!s $111.1 Each $ . Fencing, chain link, gale $277.6. Each $ . Fencing, split rail, 3' high (2-rall) $10.54 LF 85.01 7,161 sf (0.16ac) $ 895.90 Fencing, temporary (NGPE) $1.2( LF $ . Signs, sens~ivearea boundary $2.50 Each 1.00 $ 2.50 I TOTAL $ 098.40 OTHER ITEMS MAINTENANCE AND MONTIORING Maintenance and Monforing Inspection, lnal LAND COSTS LONG TERM SITE MANAGEMENT MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS $ $ Percentage of Construction Cost Unit (Construction Cost Subtof&I) TOTAL NOTE: Pro;ects with multiple permit requirements may be required to have longer rnonitonng and maintenance terrn5. This will be evaluated on a case-by- case basis for development applications. Monitonng and mamtance ranges may be assessed anywhera from S to 10 years. TOTAL Unit Cost Unit Quantity Description 56,000.00 Acre 0.16 South/Urban Unit Cost Unit Quantity Number of years 85.00 Acre 1 20 Total $ 21,603.80 $ 30,245.32 2,700.00 3,600.00 724.50 $ 579.60 Cost $ 8,960.00 $ 1,700.00 $70,113.22 I I I I I I I I I I I I I I I I I I r •• PRELIMINARY TECHNICAL INFORMATION REPORT Proposed Plat of Cavalla East Side of 162nd Avenue S.E. South of S.E. 137th Place King County, Washington IAJ.IN FILE COPY Prepared for: KBS 111, LLC 12320 N.E. 8th Street, Suite 100 Bellevue, WA 98005 ~~©~~W~[g) JAN 1 2 2006 K.C. D.D.E.S. December 21, 2005 Our Job No. 11778 lo:PIRES 10/10/ ® Lo&>fooo J CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENT AL SERVICES 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 FAX BRANCH OFFICES + OLYMPIA, WA + TEMECULA, CA M+..I~'£ ~A www.barghausen.com II' I . 1 C, \ ') '\[' \ ~J \ ': I I I I I I I I I I I I I I I I I ,, r 1.0 2.0 3.0 TABLE OF CONTENTS PROJECT OVERVIEW Figure 1 -Technical Information Report (TIR) Worksheet Figure 2 -Vicinity Map Figure 3 -Drainage Basins, Subbasins, and Site Characteristics Figure 4 -Soils Map CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of Core Requirements 2.2 Analysis of Special Requirement No. 1 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrology C. Performance Standards D. Flow Control System E. Water Quality System I 1778.005.doc [JPJ/tep] I I I I I I I I I I I I I I I I I • 1.0 PROJECT OVERVIEW The proposed plat of Cavalla is approximately a 9.4-acre site located within a portion of the Southeast quarter of Section 14, Township 23 North, Range 5 East, Willamette Meridian, King County, Washington. More specifically, the site is located on the eastern side of 162nd Avenue S.E. and 200 feet south of S.E. 137th Place and is fairly rectangular in shape. The enclosed Figure 2 -Vicinity Map, depicts the approximate location of the proposed site. The existing topography is such that it is undeveloped and consists of forested areas over the entire site. The site tends to slope at an approximately grade of 8 percent in a north to southwesterly direction. There is one existing single-family residence located in the northwest comer of the project site. This residence will be demolished with the construction of this plat. The storm drainage facility is proposed to be located in the southwest comer of the project site such that the site will discharge in the same locationit does under existing conditions. There are no wetlands located on this project site and road improvements are proposed for half-street widening of 162nd Avenue S.E. This is why the flow control calculations utilized 9.91 acres of development rather than 9.4 acres, since there are road improvements along the western property line of the site. The western boundary of the project site is formed by 162nd Avenue S.E. The plat of Liberty Lane forms the project site's northern boundary. Unplatted land, which may be a park area, forms the eastern boundary of the project site. There is a proposed development located south of the project site that will probably be developed concurrently with this project since it has been previously submitted to King County for plat approval. The proposal for this development is to subdivide the property into 34 separate lots with a separate tract for access to some of the Jots, and another tract for stormwater quality and a flow control facility. In addition, road improvements will be constructed throughout the project to provide access to the project's lots. Elevations on the site range from 480 along the northern property line down to 432 along the southern property line at the southwest comer of the project site. There is an approximate 5.4-acre upstream basin contributing runoff to the northern property line of the project site. This runoff is channeled along the perimeter of the property line of the site and discharges at the northwest comer of the site near a ditch onto the road improvements proposed for this development. This ditch will be collected by a catch basin and pipe conveyance system at the northwest comer of the site and routed, in a separate system bypassing the on-site pipe conveyanct, system, discharging to the detention pond. This upstream basin will be routed through the road improvements and will discharge further downstream, much as it does under existing conditions, at the southwest comer of the property site. 11778.005.doc [JPJ/tep] I I I I I I I I I I I I I I I I I I I King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIA) WORKSHEET Part 1 PR!ildECT OWNER AND PROJECT ENGINEER Project Owner KBSIII,LLC Address 12320 N.E. 8th Street, Suite JOO Bellevue, WA 98005 Phone Project Engineer Ali Sadr, P .E. Company Barghausen Consulting Engineers, Inc. Address/Phone 18215 -72nd Avenue South Kent, WA 98032 / ( 425) 251-6222 Part3 l"IPE OF PERMIT APPLICATION [8] Subdivision HPA D Short Subdivision 0 Grading D Commercial D Other Part·s SITE Cl:IMMtlNITY AND DRA'IN'.AGE-B'ASIN Community Renton Hiochlands Drainage Basin Cedar River Part6 SITE CHARACTERISTICS D River D Stream D Critical Stream Reach D Depressions/Swales D Lake D Steep Slopes Part2 PRQ!/El':T'leE:AIEl0NcAN&,lilESCBIPTION Project Name Proposed Plat of Cavalla Location Township 23 North Range 5 East Section 14 Part4 OTl'IEf'l'RE.VJEWS AND•PEFIMITS D DFWHPA D Shoreline Management D COE404 D Rockery D DOE Dam Safety D Structural Vaults D FEMA Floodplain D Other D COE Wetlands D Floodplain D Wetlands D Seeps/Springs D High Groundwater Table D Groundwater Recharge D Other 11778.005 doc [JPJ/tep] I I I I I I I I I I I I I I I I I I I Part 7 SOILS Soil Type Slopes Alderwood D Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE D D D D D Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION l2l Sedimentation Facilities ~ Stabilized Construction Entrance [8J Perimeter Runoff Control D Clearing and Grading Restrictions 12] Cover Practices l8J Construction Sequence D Other Part 10. SURFACE WATER SYSTEM D Grass Lined Channel D Tank 121 Pipe System D Vault D Open Channel D Energy Dissipater 121 Dry Pond D Wetland 121 Wet Pond D Stream Erosion· Potential Erosive Velocities LIMITATION/SITE CONSTRAINT D D D D D MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surtace Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris Ensure Operation of Permanent Facilities Flag Limits of SAO and Open Space Preservation Areas Other-----------------~ Infiltration Method of Analysis Depression KCRTS Flow Dispersal Compensation/Mitigation Waiver of Eliminated Site Storage Regional Detention Level 2 Flow Control Brief Description of System Operation Catch basin collection to oioe conveyance to wet/detention oond then disoersed. Facility Related Site Limitations Reference Facility Limitation I 1778.005.doc [JPJhep) .•. ,.,.,.,. ' s :i ! ' !i i1 !I I' ,1 ; H~,1cr-,: --~};1 !( ~~s! •• §~ii ~~i !J "! '. i i J " ' l ". t, "'\ I ' . \' ii(~ :n If ~~ 8 .24 ill.i.__J tr I 452.,6 -, ~5~ ffl.42 --al~ \ l T LI i ' '/. / ,I ,o "'""'"... I U .A I ~ 0..1 o<I 11!1!.... S~alo, .q..G '"'""'v" 1821 5 72ND AVENUE SOUTH ..,, - 11778 ~-~ KENT. WA 91$032 a.u .. n .SGIII t<ar1:1onta1 41 __ .,. (425)251-6222 1"•,0' I -'. -: (425)251-8782 FAX c~..,~•d .......t.s- ShHt \ l Ap~ • .0K6... V.rtlcol '1 o,· CML ENGINEERING, LAND PU.NNING, N/~ (,<.,. ~\.'1-SUfNE'J'ING DMRON~ENT,'.1. StRVlCts o.,. 12,lm/o, _§_ ( '"'a EH01>' • l ' /(WfJ£J!l.Y~.~) for, ' I, :rxw,, ', J:d\p,~;,.,.:,~.-. ·, J, ns-.-1,,. d~; fJol•/'·"'• r;/.o,y:o,,~ ,, ie Sea"'· ,~~o ,~am/ell x.-~r, , , 1 77$-~ .• ·! 1 77fl-~,,, 111~-r,l,<ia~-~.,1 I lJ$-~ I gGil ~~o ·j i • ! .~ ~un .. • ~---;-',--,~J+--c~~~-'-~ •'', 11· '·< i, ,.._--;, "'·--~.-· -/ _;'8 .-··hr,,. " I ~,, 45J,~, e1 .,,., I g 4!5j7 ·~ 1.2; ~ g I "'" .illJl. ~ { '" _!!![ll'SECllQN-\-Or -... o..c 51.0..: 1 1 l • ~. -c i ! ~ 1' ~ .. I i I I I \ I \ Ha. I t>me I ~JE~· I ~r,c. ID> ~ 7 ~Wlfl 1 11 qg ~ 1,11 . . r 'ii l,i 8 .• PV!sr~ .. 1-Ho• P',l ELEV "' 459.20 R""ioloo KBS DEVELOPMENT CORP. 12320 N.E. 8TH STREET, STE. 100 BELLEVUE, WA 98005 PRELIMINARY ROAD AND PROFILES AND DRAINAGE PLAN FOR CAVALLA I II I LEVEL 1 OFF-SITE DRAINAGE ANALYSIS Proposed Plat of Cavalla East Side of 162nd Avenue S.E. South of S.E. 137th Place King County, Washington Prepared for: KBS Ill, LLC 12320 N.E. 8th Street, Suite 100 Bellevue, WA 98005 November 14, 2005 Our Job No. 11778 !emacs ll)/ l 0/ Oy, CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 18215 72NDAVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 FAX BRANCH OFFICES + OLYMPIA, WA + TEMECULA, CA + WALNUT CREEK. CA www.barghausen.com ' / / \ ______ ./ i //' ,I ' I ""--I ---1~ 1---__j---'---' -DOWNSTREAM "' \ g DRAINAGE SYSTEM " 1---r----J1 " --~ MAP I 11~1 I I ) ' I I I I I I I I I -.~ i ' ":" ...... -- '""' ·------- '" ~ -.,.,,,, ... :;"'. /;f,....., I ::,. • IT \ t>"~ ·~ HIL~ !l11J~1\ ~ "'"'-".,':.<" '''"" ' ' ' : u,« - ,., • .,.,,, nDll•I I .. I , I I~····-~~- : I FIVE I I i · I r" .,,.. _ I 1-----1,V,~.fr:1 _..;;_ .. __ ::_J, .. i ""'" ,1,1 ... , -• -.c. , I I ! ACRE TRACTS S\TE. I "' .. ,., "" I I I • • • • • • • I I I I I I ·.;-;,,_. I '"'!t. TASK2 RESOURCE REVIEW • Adopted Basin Plans: The site is part of the Lower Cedar River drainage basin. • Finalized Drainage Studies: This is not applicable . • • • • Basin Reconnaissance Summary Report: Once again, the site is located in the Lower Cedar River drainage basin and drains to an area that has no mapped tributary (which would have been mentioned in the basin reconnaissance summary report if it had its own drainage basin) . Critical Drainage Area Maps: According to the water quality applications map in the 2005 King County, Washington Surface Water Design Manual (KCSWDM), Basic Water Quality treatment is required. According to the flow control applications map, also in the 2005 KCSWDM, Conservation Flow Control (known as Level 2 Flow Control) is required as a minimum. Floodplain and Floodway FEMA Maps: Please the enclosed Exhibit D -FEMA Map utilized for this analysis. Panel No. 1,001 of 1,725, Map No. 53033Cl001 F, revised May 16, 1995, indicates that the proposed project site does not lie within a floodplain or flood way of a stream . Other Off-Site Analysis Reports: A review of Exhibit I -Basin Reconnaissance Summary Report and the site investigation work conducted in the preparation of this Level 1 Drainage Analysis. The U.S. Department of Agriculture Soils Conservation Service (SCS) soils map is also provided (see Exhibit F -SCS Soils Map). In addition, the off-site analysis prepared for the project site located immediately south of this site was reviewed for conformance with the findings from the off-site analysis performed for this project. Sensitive Areas Folios: Based on a review of the King County sensitive areas map folios, it was found that the subject site does not lie within a sensitive area. However, it does drain to a landslide hazard area further downstream from the project site and, ultimately, into the Cedar River, which is a salmon-bearing river. There are no wetlands or coal mine hazards, etc., associated with this project site or the downstream drainage course. Road Drainage Problems: This is not applicable. United States Department of Agriculture King County Soils Survey: Based on our review of the soils map for this area, the entire site lies within Alderwood type soils. Wetland Inventory Map: The wetland inventory map for this area was reviewed and it was determined that there are no wetlands on the site or in the downstream drainage course of the site. Migrating River Studies: This is not applicable . 11778.003.doc RECONNAISSANCE REPORT NO. 13 LOWER CEDAR CREEK BASIN JUNE 1987 Natural Resouoces and Parks Division and Surface Water Management Division King County. Washington I I I I I Department of Public Works Don LaBelle, Director King County Executive Tim llill King County Council Audrey Gruger, District 1 Cynthia Sullivan, District 2 Bill Reams, District 3 Lois North, District 4 Ron Sims, District 5 Bruce Laing, District 6 Paul Barden, District 7 Bob Grieve, District 8 Gary Grant, District 9 l'luts, Planning and Resources Joe Nagel, Director Surface Water Management Division Joseph J. Simmler, Division Manager Jim Kramer, Assistant Division Manager Dave Clark, Manager, River & Water Natural Resources and Parks Division Russ Cahill, Division Manager Bill Jolly, Acting Division Manager Derek Poon 1 Chief, Resources Planning Section Bill Ec.keli Manager, Basin Planning Program Resource Section Larrv Gibbons, Manager, Project Management and Design Section Contributing Staff Doug Chin. Sr. Engineer Randall Parsons, Sr. Engineer Andy Levesque, Sr. Engineer Bruce Barker, Engineer Arny Stankus, Engineer Ray Steiger, Engineer Pete Ringen, Engineer Consulting Staff Don Spencer, Associate Geologist, Earth Consultants, Inc. John Bethel, Soil Scientist, Earth Consultants, Inc. P:CR Contributing Staff Ray Heller, Project Manager & Team Leader Matthew Clark, Project Manager Robert R. Fuerstenberg, Biologist & Team Leader Matthew J. Bruengo, Geologist Lee Benda, Geologist Derek Booth, Geologist Dyanne Sheldon, Wetlands Biologist Cindy Baker, Earth Scientist Di Johnson, Planning Support Technician Robert Radek, Planning Support Technician Randal Bays, Planning Support Technician Fred Bentler, Planning Support Technician Mark Hudson, Planning Support Technician Sharon Clausen, Planning Support Technician David Truax, Planning Support Technician Brian Vanderburg, Planning Support Technician Carolyn M. Byerly, Technical Writer Susanna Hornig, Technical Writer Virginia Newman, Graphic Artist Marcia McNulty, Typesetter Mildred Miller, Typesetter Jaki Reed, Typeseller Lela Lira, Office Technician Marty Cox, Office Technician II • I I I II TABLE OF CONTENTS 1.· SUMMARY II. INTRODUCTION Ill. FINDINGS IN LOWER CEDAR RIVER BASIN IV. V. A. Overview of Basin B. Effects of Urbanization C. Specific Problems 1. 2. 3. Drainage and flooding problems Damage to property Destruction of habitat RECOMMENDATIONS FOR ACTION A. Reduce landslide hazards B. Reduce erosion and flooding C. Prevent future erosion and flooding with appropriate analysis, planning, and policy development D. Stop present (and prevent future) damage to habitat by addressing specific problems in stream systems MAP APPENDICES: APPENDIX A: APPENDIX B: APPEDDIX C: Estimated Costs Capital Improvement Project Ranking Detailed Findings and Recommendations 1 1 2 2 4 5 5 6 6 7 7 7 s s 11 A-1 B-1 C-1 I II I. SUMMARY The Lower Cedar River Basin, in southwest King County, is unique in its development pat- terns and the associated environmental problems that appear throughout lhe basin. Except for the city of Renton and areas on the Cedar River Valley floor, most of the development in the basin has occurred on the upland plateaus. Most of this development is recent and primarily residential. In addition, the plateau is the site of numerous sand and gravel mining operations and, in the southern uplands, an abandoned coal mine. Peat is also being mined north of Otter Lake. In some areas livestock are being raised on small farms; there are no major crop-related agricultural activities in the basin. The effects of development are most apparent where stonn drainage is routed over the valley walls. Impervious surfaces on the plateau ba1IC increased the rate and volume of storm runoff, resulting in substantial erosion, siltation, and Hooding below. ln addi- tion, erosion and siltation have damaged or destroyed habitat in many tnbutaries, threatening the survival of fish. Habitat and water quality throughout the basin are also threatened by the filling of wetlands and the presence of l3Jge amounts of domestic trash in some streams. The reconnaissance team noted that the Peterson Creek system has so far remained in its natural, nearly pristine condition. Maintaining this quality should be a high priority in future basin planning capital project programs. Recommendations in the Lower Cedar River Basin include 1) designing and oonstructing appropriately sized RID and other drainage facilities; 2) establishing stricter land use policies regarding floodplains, wetlands, and gravel mining; 3) conducting more detailed and comprehensive hydraulic/bydrologic analyses of proposed developments; and 4) preventing damage to the natural drainage system. The field team also recommends 5) restoring the habitat of several tributaries (e.g., cleaning gravels, revegetating stream banks, and diversifying streambeds for spawning and rearing) as well as 6) protecting the nearly pristine quality of Peterson Creek. INTRODUCTION: History and Goals of the Program ln 1985 the King County Council approved funding for the Planning Division (now called the Natural Resources and Parks Division), in coordination with the Surface Water Management Division, to conduct a reconnaissance of 29 major drainage basins located in King County. The effort began ,,.,th an initial investigation of three basins -Evans, Soos, and Hylebos Creeks •• in order to determine existing and potential surface water problems and to recommend action to mitigate and prevent these problems. These initial investiga- tions used available data and new field observations to examine geology, hydrology, and habitat conditions in each basin. Findings from these three basins led the King County Council to adopl Resolution 6018 in April 1986, calling for reconnaissance to be completed on the remaining 26 basins. The Basin Reconnaissance Program, which was subsequently established, is now an important ele- ment of surface water management. The goals of the program are to provide useful data v.ith regard to 1) critical problems needing immediate solutions, 2) basin characteristics for use in the preparation of detailed basin management plans, and 3) capital costs associated with lhe early resolution of drainage and problems. The reconnaissance reports are intended to provide an evaluation of present drainage con- . ditions in the County in order to transmit information to policymakers to aid them in , developing more detailed regulatory measures and specific capital improvement plans. They are not intended to ascribe in any conclusive manner the causes of drainage or erosion I Lower Cedar River Basin ( continued) problems; instead, they are to be used as initial surveys from which choices for subsequent detailed engineering and other professional environmental analyses may be made. Due to the limited amount of lime available for the field work in each basin, the reports must be viewed as descriptive environmental narratives rather than as final engineering conclusions. Recommendations contained in each report provide a description of potential mitigative measures for each particular basin; these measures might provide maximum environmental protection through capital project construction or development approval conditions. The appropriate extent of such measures will be decided on a case-by-case basis by County offi- cials responsible for reviewing applications for permit approvals and for choosing among competing projects for public consrruction. Nothing in the reports is intended to substitute for a more thorough environmental and engineering analysis possible on a site-specific basis for any proposal. ill. HNDINGS IN LOWER CEDAR RIVER BASIN The field reconnaissance of Lower Cedar River Basin was conducted in January 1987 by Robert R. Fuerstenberg, biologist; Bruce L Barkeri engineer; and Lee Benda, geologist. Their findings and recommendations are presented here. A. Overview of Lower Cedar River Basin The lower Cedar River Basin is located in southwest King County and is 27 square miles in area. It extends southeast from the mouth of the Cedar River on Lake Washington to approximately river mile 14.0. The boundary to the northeast is marked by a ridgerop connecting the city of Renton to Webster and Franklin Lakes; the boundary to the southwest runs along Petrovirsky Road to Lake Youngs. Renton is the only incorporated area in the basin. Other population centers include Fairwood, Maplewood Heights, and Maple Valley. Except for the city of Renton, most of the residential concentrations arc located on the upland plateaus overlooking the Cedar River Valley. These upland developments are recent compared to the smaller estal:>lished communities on the valley floor. The basin lies v.ithin portions of three King County planning areas: Newcastle in the no_rtheast (which includes Renton), Tahoma-Raven Heights in the east, and Soos Creek (the largest of the three) in the west. Rural areas exist on the valley floor on both sides of the Lower Cedar River, from approximately river mile 5.50 to 13.00. These are limited to pas1ureland for horses, rov,:s, and some sheep and several small "u·pick" fntit and vegetable farms. Similar areas are located on the southern uplands above the reach from river mile 5.50 to 7.00 and in the Lake Desire-Otter Lake area. The plateau is also the site of sand and gravel mining operations and~ in the southern uplands, of the abandoned Fire King Coal Mine. Peat deposits exist west of Lake Desire and north and south of Otter Lake, and peat mining is being carried out north of Otter Like. Present zoning allmvs for urban and suburban densities throughout much of the basin, particularly on the upland plateaus and in the Cedar River Valley from its mouth 10 appoximately river mile 6.50. Population projections for the year 2000 in the three plannign areas containing the Lower Cedar Basin are over 311,000; an increase of 47 2 I • I • • • I I I P:LC Lower Cedar River Basin ( continued) percent from the present. Most of this growth will occur m the Soos Creek Planning Area . Dominant geological and geomorphic features. The geology of the Lower Cedar River Basin is diverse. Geological formations exposed along the valley include sedimentary rocks, undifferentiated older glacial dri(t, e""lensive ground moraine deposits, recent alluvium along the Cedar River, and landslide deposits along the river and its tribu- taries. The sedimentary rocks, composed of moderately dipping sandstones, con- glomerates. mudstones, and shales, are exposed locally along the cliffs of the Cedar River Valley near the mouth of the Cedar River. In addition, the Renton formation, composed of sandstones, mudstones, and shales with periodic deposits of coal, is also exposed along the lower ponion of the Lower Cedar River Valley. Undifferentiated glacial deposits found here are composed of three or more till sheets, glacio-fluvial sand and gravel, glacio-Jacustrine clay, and sand, and non-glacial sand. clay and thin peat. These lie over the sedimentary rock formations and are best exposed in cross-section along the cliffs of the main valley and major tributaries. The morphology of the Lower Cedar River Basin is dominated by the valley formed by the Cedar River. Valley walls are steep cliffs formed by landslides in glacial sedi- ments. A once extensive and meandering River~ which created a wide valley floor as it cut its v.-ay westward, the Cedar today is diked for most of its length through the lower valley. A narrow but extensive band of landslide deposits exists along the steep cliffs of the main river and its major tributaries. The landslide deposits consist of deformed bJocks of glacial sediments and colluvium derived from slides or mass flowage, such as landslides and debris flows. Recent alluvial deposits fill the valley and major tributaries. Small, composite, alluvial debris fans exist at the mouths of the largest tributaries. Closed depressions, principally in the uplands. have Jacustrine and peat deposits. The Lower Cedar River Valley has a high potential for erosion due 10 steep slopes and the existence of a clay layer that promotes soil failures. In addition, the confined nature of tributary channels bern.·een steep hillslopes promotes bank erosion during high flows. Numerous recent landslides are evident along cliffs of many of the steep tributaries and along the main stem of the Cedar River. These have been accelerated by the removal of vegetation and the routing of concentrated storm flmvs over steep slopes in areas where development has occurred. Hydrologic and hydraulic characteristics. The Cedar River Basin is composed of a complex drainage nem.·ork consisting of the Cedar River and 17 tributaries. The larger tributaries begin in lakes or wetlands on the bluffs and flow through relatively flat: stable channels to the edge of the Cedar River Vallev, then plunge down to the vallev floor through steep, erodible ravines. Tributaries of this type such as Tributary 0304 (with headwaters at Wetland 3111) and Tributary 0323 (which begins at Lake Desire). are found on the south side of the Cedar River. Another type of tributary collects surface runoff from urbanized areas. pastureland, and wooded areas. Tributaries 0302, 0307, and 0312 are examples of this type of tributary. They are intermittent (depending on rainfall), shoner in length, flow through shallower channels that are steeper al the bluffs and transport more material during times of 3 I • I I Lower Cedar River Basin (continued) high flows. Some of the worst problems located during field investigation (see Appendix C for a full listing) occur on this type of tributary. Catchments 5, 6, and 12 have very infiltrative soils. RID poinds to effectively infiltrate all urban runoff hillslopes. lbe infiltrated runoff then reappears as Urban developments hvae utilized before it reaches the valley springs. Two large lakes (Desire and Otter), together with four smaller ones (Shady, Peterson, Webster, and Francis) lie in the southeast third of the basin. Numerous large wetland areas exist in this section as well. The field team identified JO potential wetland sites that had not been previously identified in the Sensitive Areas Map Folio (SAMF). The system of lakes and wetlands in this area effectively buffers the high nows draining to these tributaries. Habitat characteristics. With few exceptions, usable fish habitat exists only in peren- nial streams (i.e., Trib. 0302, 0304, 0305, 0328, and possibly 0308). In other streams (e.g., Trib. 0303 and 0310), steep gradients preclude fish use. Steep gradients also reduce fish use in the perennial systems (except for Trib. 0328). Habitat is in various stages of degradation in these systems; pools are being filled and gravels and debris shift regularly. In Tributary 0328 (Peterson Creek), however, habitat diversity is extensive, and the channel is not seriously degraded. At this location the field team observed at least three species of salmonoids. In general, the most diverse and least disturbed habitat in a tributary system occurs in the large wetland areas in the southeast third of the basin. Usable habitat for anadromous fish is found in the low-gradient portions of streams where channels cros.s the Cedar River Valley floor. In these reaches, however, only spawning habitat is likely to be available, as the pools and woody debris necessary for successful rearing either do not exist or are quite limited. Excellent spawning and rearing areas exist where pools and riffles are extensive, instream cover and bank vegetation are intact. and diversity of habitat types is abundant. B. Effects of Urbanization in the Basin Flooding, erosion, and the degradation of habitat associated with development in the Lower Cedar River Basin are most apparent where development has eliminated vege- tation along the edges of the valley and where stormwater has been routed down channels and S\\-·ales. The removal of vegetation, such as trees, above and below the edges of valley wall~ as well as the discharging of stormwater over the valley wall, has resulted in tension cracks and landslides that are endangering some houses. The sedi- ments from these failures are depositing in streams and on valley floors and damaging fish habitat and private property. Discharging stormwater from increased impervious areas into steep tributary channels and swales is seriously destabilizing channels and valley walls; this in turn results in channel downcutting, bank erosion, and landslides. The sediments from these problems often degrade fish habitat and settle out on pri- vate property along the valley floor. Two serious instances of development~related erosion occurred during the November 1986 storm: 1) culverts rerouting the srream were plugged: causing the formation of a new channel that destroyed portions of roads on Tributary 0314; and 2) new, uncom- 4 II Lower Cedar River Basin ( continued) pacted fill adjacent to new residences near collection point 5 was washed partly away during the storm, causing landsliding and gullying. Future problems win be similar to these, as commercial and residential developments increase flow rates and volumes by decreasing natural storage and infiltration. This is expected to occur if wetlands on the upper plateau are encroached upon or lost (e.g., on Trib. 0304 at RM 2.30 and on Trib. 0304A at Rm 1.60). The preservation of wetlands and streambank vegetation and the attenuation of storm flows are essential in this basin. C. Specific Problems Identified The steep valley sideslopes through which streams pass and the often dense upland development result in a number of similar problems that repeat themselves throughout the Lower Cedar River Basin. The most significant of these are ou1lined and discussed below. 1. Drainage and flooding problems are often the result of several conditions: a Undersized culverts and inadequate entrance structures. The most notable area is on Tributary 0306 at river mile .30, where a culvert here was blocked by debris carried downstream by the stream and caused erosion and flooding of Fairwood Golf Course. The blockage was compounded by the fact that the culveI1 was undersized; the problem will wor.;en as flows increase from upstream development. b. Serious instream erosion and subsequent downstream sedimentation. These have been caused by three main factors: 1) runoff from residential developments on the bluffs above the valley, 2) compacted pastureland due to livestock, and 3) runoff from impetvious areas originating at gravel pits. These problems will continue and worsen until mitigative measures are taken. (See Appendix C for specific examples.) c_ Undersized n:cbannelizcd streams. Tributaries on the valley floor are too small to carry the increased flmvs originating in developed residential areas along the top of the bluffs. For example, Tributary 0302 at river mile .25, the channel along Maplewood Golf Cour.;e, overlaps and floods during storms. d. Construction in wetland and floodplain areas, Many of the wetlands on the south side of the Cedar River are peat bogs., and roads built through them continue to settle each year, increasing the amount of flooding on the road. For example, the road crossing with Tributary 0328B north of Lake Desire will experience more severe flooding as the road settles. e. Discharging of stonnwater at the top of steep banks. At river mile 2.20 on the Cedar River, a trailer park ( constructed on the edge of the cliff) discharges its drainage down the valley wall. Increased flows erode the steep valley, depositing sediments on the valley floori blocking channeJs and causing flooding. These problems will eventually stabilize. but onJy afler a large quantity of soil has been eroded. 5 Lower Cedar River Basin ( conlinued) 2 Damage to property is being caused by three factors: a. Landslides and potential landslides. Landslides are accelerated by the· removal of vegetation on steep slopes in prepararion for residential construction and/or by the routing of storm flows over hillslopes. For example, a large landslide has already occurred in the front yard of a resi- dence on the Cedar River at river mile 7.80. b. Sedimentation (from landslides). Sedimentation and channel and sion are damaging private property along the valley floor (Trib. 0310). hank ero- 0299 and c. Aooding during storms. Flooding has been brought on by the effects of development and associated changes to the natural drainage systems In the basin. (See "B" above.) 3. Destruction of habitat is being caused by four conditions: a. Sedimentation of pools and riffles and cementing of gravels. These problems, the result of severe erosion and the transport of bedload material, have been caused by upland developments in the basin and the presence of associated impervious surfaces, which increase the rare and quantity of surface runoff. Sedimenta1ion and cementing of gravels in streambeds destroy natural spawning and rearing habitat. On Tributary 0307 at river mile .40 and Tributary 0305 at river miles .95, 1.20, and I. 70, recent high flows have eroded the srreambed at least one foot~ conrributing to a serious siltation problem downstream. Heavy bedload transpo11 is evi- dent in all systems of the basin except Trit>utary 0328. In Tributary 0303 at river mile .25, fine sediments are accumulating: in gravels that may be used by resident fish. In Tributary 0304 between river miles .95 and 1.20, pools are being filled by sands and gravels and rearing habitat is being rapidly lost. b. O.annelizatioo of stream beds. Loss of habitat through channelization has occurred in all the major streams of the basin. but most noticeably in those reaches that cross the valley floor. These reaches Jack habilat diversity, reducing fish use for spawning and rearing. Channelization has damaged or destroyed habitat in several reaches that were once heavily used by fish; these include Tributary 0302 between river mile .30 and 40, Tributary 0304 l:len.veen river miles .O~ and .18, Tributary 0305 between river mile .20 and .75, and Tributary 0328 from river mile I.JO to !AO. These systems cannot afford a fuI1her reduction of habitat and still remain viable fishery resour- ces. c. The accumulation or trash in Slream beds. This problem occurs in close proximity to residential areas. Trash degrades water quality and is visually unpleasant. Tires, appliances, furniture, and other trash have l>een thrown into Tributary 0302 at river miles LOO and 1.10 and in Tributarv 0303 at river mile .35. 6 I I I Lower Cedar River Basin ( continued) Wetland encroachment. Encroachment destroys habitat and eliminates natural water filtration and storage for surface runoff. Examples of this problem were observed on Tributary 0304 at river mile 2.30. Tributary 0308 at .80, and Tributary 0304A at river mile 1.80. Many wetlands have already been completely lost through filling, for example on Tributary 0306A at river mile .55. Suspected violations were forwarded to Building and Land Development for enforcement. RECT>MMENDATIONS FOR ACl10N The primary recommendations for action in the Lower Cedar River Basin addresses current severe problems related to erosion, habitat destruction, and nooding. Prevention of these problems will be accomplished by controlling locations and densities of new development and providing adequate R/D facilities for stormwater. A Reduce landslide hazards by: I. Including sensitive areas not previously mapped on the Seositivc Areas Map Folio (SAMJ<'). See Appendix C for a full listing of sensitive areas. 2. Establishing building setbacks along cliffs and native growth protection easements along steep ravines. 3: Discouraging or eliminating the routing of stormwater over cliffs, unless adequate tightline sysrems can be constructed to convey no,..,.-s in a safe. nonerosive manner to the bottom of cliffs. 4. Decreasing peak flows by constructing larger RID facilities to le~sen the landslide and erosion occurrence along tributary slopes. B. Reduce erooion and flooding in the basin by improving surface water management: 1. Direct the Facilities Management Section of the Surface Water Management Division to evaluate existing storm-<letention and conveyance facilities to deter- mine whether they are properly sized to meet current standards. Evaluation should begin wilh aJI single-orifice R/D facilities. 2. Consider areas other than wetlands as regional storm-<letention facilities. Triliutary 0300 at river mile .42 is the site for a proposed dam? for example. 3. Utilize existing lower quality wetlands (tboo;c rated other than #1) as regional storm-<letention facilities. Wetlands 3102 and 3142 could provide more live storage~ for example. 4. Review channel and culvert capacity for conveying existing and future runoff, and establish floodpJain areas in regions of slight gradient for existing and future runoff conditions. 5. Promote tbe infiltration of surface water through the use of retention facilities and open channels instead of pipes where the soil and slope conditions permit. Collection points 5. 6, and 12 on plateaus have such soil conditions. 7 I I I I ' ' '~ .. C. Lower Cedar River Basin (continued) Prevent future problems of erosion and flooding with appropriate analysis, planning, and policy development related to surface water management: 1. 2 3. 4. Conduct a detailed, comprehensive hydraulic/hydrologic analysis of any propcx;ed developments to determine impacts on the drainage courses downstream. This 1s especially critical for areas on the upper bluffs and plateau, which drain over sleep, sensitive banks above the Cedar River. Conduct a study of the impact of locating infiltration ponds utilized near the edge of the bluffs to determine their effect on seepage faces on the lower face of the bluffs. This might be accomplished with a computer-based numerical model of the groundwater flow. Requin: the tightlining of stonn drainage down steep or sensitive slopes when they cannot be directed away from the slopes. This is done by piping the flow down the slope and discharging it at the bottom with adequate energy dissipation. Many of the intermittent tributaries flowing down the IJanks should be tigh1lined as urban development increases flow to them. Construct new R/D ponds with fdter berms to improve water quality and reduce fine sediment loads. New RID ponds should have two cells with gravel-berm filters and vegetated 5\\-'ales at the inlet and outlet. Consider Tributaries 0304, 0304A, 0301, and 0303 as sites for this type of facility in order enhance water quality. 5. Maintain natural vegetation on streambanks and floodplains. This is especially impo11ant for relatively flat channels flowing on the plateau before they reach the steep bluffs because these channels and their floodplains will attenuate flows during times of heavy runoff. 6. Maintain buffer an:as around wetland& Many of the tributaries on the south side of the Cedar River headwater at werlands. These wetlands act as natural storage areas during storms. 7. Reevaluate King County policy regarding permitting £or gravel mining on steep, sensitive slopes. 8-lncludc the city of Rention in future interlocal agreements for planning and capi- tal improvement projects where city and county interes1s overlap. D. Eliminate present damage lo habitat and prevent future damage by addres.sing specific problems in the stream systems. The following activities should be coordinated among King County, the Muckleshoot Indian Tribe, and State Departments of Fisheries and Game: 1. Reduce damaging storm flows with greater de1ention volume and lower release rates at upstream developments. 2 Implement restoration projects on Tributaries 0304 (river mile .00-.20), Tributary 0305 (river mile .20-.80), Tributary 0303 (river mile .25-.35), and Tributary 0328 (river mile 1.10 -1.40): 8 I I • I I I I ' i 3. ]Ii ,,,: )P:LC Lower Cedar River Basin ( continued) a. On Tnl>utary 0304: Oean streambed gravels, add habitat and bed-control weirs, and plant bank vegetation for shade. b. On Tnbutary 0305: Construct a new channel and move stream from road- side channel to its new location on adjacent lands. Implement a full restoration project to provide channel meanders, habitat structures, pool/rime enhancement, streambed gravel replacement, and revegetation. c. On Tnl>utary 0303: Move stream from present channel to a location further north, away from the roadside. If relocation is not possible, these minimum steps should be taken: Add habitat structure to existing channel with root masses, deflectors, boulder clusters, and other features; revegetate channel banks with shrubs and small trees; enhance stream crossings with bottomless pipe arches. d. On Tributary 0328 (Peterson Creek): Add habitat structure by replacing the straight, shortened channel with a more natural, meandering one; place habitat structures (such as root masses, deflectors, cover logs, and boulder clusters) throughout the channel; and revegetate banks "'ith shrubs common to adjacent riparian zones (salmonberry, ninebark, or dogwood, for example). Protect the Peterson Creek system (Tnb. 0328) in its present, near-pristine stale. This will include not only the restoration outlined in section A above, but also the adoption of land use management regulations to prevent future habitat destruction: a. Protect an existing wetlands within the subcatchments of Peterson Creek. Employ wetland buffers at least 100 feet wide "'ithout exception. b. Restrict development in the critical headwater area (drainage, habitat, water quality) bounded by Lake Desire, Otter Lake, and Peterson Lake lo rural densities. c. Designate and protect streamside management woes of at least 100 feet from the ordinary high-water mark (OHWM) along the main stem of the creek. Use 25 feet from the OHWM on tributaries. d. Preserve floodplains and their forests for dynamic retention of sediments and water. e. f. g. Restrict y,:getation removal in stn:amside/wetland management zones. Size R/D facilities to store the 100-year storm at a two-to-five-year release rate. Use the two-cell type of pond with a forebay, a gravel filter, and a vegetated swale outflow where feasible. Regulate more closely an septic tank and drain-rield installations, as well as maintenance schedules, panicularly in the Lake Desire, Otter Lake, and Peterson Lake drainage areas. 9 Lower Cedar River Hasin ( continued) h. Work with the State Department of Ecology to establish nurumum stream- Oow requirements for Peterson Creek and Lake Desire tributary. 4. Develop and promote public education and involvement programs for basin awareness. Work with school~ environmental groups, and the civic and business communities to conduct educational and restoration programs. 10 <·,-4", .' f_~ ',-"> /, ;,;;1j::.". 1.,,;_;_.: __ -.. _-~."-'(~ ==r ,,,.:·.,·_:.,11·1\-·.' . I · .. , , .· \' ' ''·'·' .J '\\ -' ,-- I ;v,· .-.. I:.·.':··.\-\ ,, J \ \ , ,,, ,\ l '' ... Jb ·\' ·-,;···' .'.·."·-. 11 ' ... · " -11-1 ' '--'" - \ \ -, i\' ;, _•' '" -;;;5 / ~\ -:;---! ' . \ \. '"...::_ ~- · u,,,,c.\~i,11 ' ,,_ '• ~ , I i')'-- \ \ 1, ,_ ' ' J,-'tUJ •:•·A~O.;,: '1--,.·_1 ·1~ - \,, .. .'~,;._ \ .)~0, \ •it ' \'--."-' ' "--". ~,hJ . ' . -~;< ). '\ \ \ . .--. -/• I / . ' \~) I • \ -' : : ,-;,, .. , ''\4f .. , f.,{ '\ _,~--1;------,-· ' ·. . ··" ,-,.~ ; ',0 · .. ·-~. " · .)}! tr\:-:-/ J--;c:?· :· --~ ... .. 1. fl, ·. I.. ... . ::,, .... . , , _ -' 1, .. :~h.;'.1 . _ : i' . "':,,;-~; '! ' C ( ~ ,.,,.,1,--+-~ ·· ti; ',,i ® ---.,,,- 0299 .3115 a ~ii':'"~~ 1 1 \ ' .. ,ij!, l ;,·(;~' .. _... '\ I __ .,_,,.....,_.,.--·· RBASIN Basin Boundary Subcatchment Boundary Collection Point ~~ (j 1 {j' /',( . ( C f Stream Tributary Number Proposed Project ;,;t,) L, 0 \__ \ \ ..• _.---.-----..______ ... _} N 1 2 MilE>S + I\ :1;l" r ' / . "- ' - 'I '--·--."--'-" -1,'J " ,- -" •.;,·-;.( r , ~/· ,\---\~ I -\i (;,--".;;:_ ® ;:, \ '- ,I \t,· /'1.,.J;h f;f£·1 ,-· ~ tr.~. ; \. / ~ ' '-';o,,,,, ·; . . , --~. I. f ( .,.. j ·~~ ... ·)/c. ' _/' ' " . ..1 ~J r,:~-/'_; '/ 11 ' / ' :I. _ ··, .. ~;'::_,,, \ 311!1. '~\ '1 \,...!!.!:U!. ·-~-;.;-· I :\\ ,:~- \,-1;~\ .J-.i..~ !J '/ J?l C " APPENDIX A ESTIMATED COSTS: PROPOSED CAPITAL IMPROVEMENT PROJECTS LOWER CEDAR CREEK BASIN ' Indicates project was identified by Surface Water Managemenl office prior to reconnaissance. NOTE: All projects are located on map included in this re.e_or1. Project Numhcr 3105* 3109* !':LC.APA Collect. Point 10 10 Project Description Enhance 2200' of Trih. 0305 from Cedar River 10 Elliot Bridge. Sccu1·e easements to wetland localed in Cascade Park and conslrucl a berm al lhe outlet. Replace existing catch basins with control stn1cturcs. Project should be justified by a basin study. Wetland rated #2. (This wetland will require forlhcr biological evaluation before R/D design nnd construction.) Problem Addressed Mitigates flooding of King County park land. Better utilizes wetlnnd 1s storage capacity to address peak flows from surrounding urban area. A-1 Estimated Costs and Comments $115,000 (NOTE: This project was proposed hy Surface Water Management, is in the design phase, and will be constructed by 1989.) $186,000 3111 (Wetland 3136) 3112 (Wetland 3142) 3114' (Wetlnnd 3150) 3115 P:LC.APA 19 18 Descri p_tion Secure easements to outlet to Francis Like and !JOO' of channel from lake to SE 184th St. Construct a weir 10 raise lake level l'i and enhance 1100' of Trib. 0317. Should be justified by a basin plan. Wetland rated # l. (This wetland wit\ require further biolop:ir.:al cvalu.:1tion before R/D design nnJ construction.) Secure easement for outlet to wetland and replace existing weir with a concrete-slotted weir. Should be justified hy a hasin plan. Wetland rated #2. (This wetland wit\ require furtht:r biological evaluation before R/D design and construction. Secure casement to Wetland 3 l50 anU construct a containment berm and control structure nt the outlet. Project should be justified by a basin plan. Wetland rated #2. (This wetland wit\ require further hiologkal evaluation before R/D design and construciton.) Instatl detention pond and 1,000' of tightlinc. Project is indepen- dently justifiable. Problem Atldl'essed Will provide additional storage to mitigate anticipated future increased flows. Will provide adtlitional storage for anticipated future peak flows. Addresses ant'iciputed increases in flow rnusetl by development. Mitigates severe erosion and flooding during times of high flows, A-2 Estimatetl Costs and Comments $175,000 $117,000 $134,000 $361,000 ~ I 16 3117 3] 18 3119 Jl20 P:LC.APA Collect. Point 21 16 JO 4 15 Proicct Description Raise existing road embankment 2-4'. Project should be indepen- dently justifiable. (Re[er to Roads Division.) Install 1,400' of tightline, a sediment trup, and 700' or channel [rom Jones Rd. to Cedar River. Prnject is independently justi- fiable. Install 300' of 36" culvert, a new inlet stn1cture, manhole1 and catch basin. Project is independently justifiable. Construct a detention dam and control structure in a deep channelized section of Ttib. 0300. Project is independently justifiahle. Constn1ct a sedimentation pond and 1,000' of channel from Jones Rd. to Cedar River. Project is indepen- dently justifiable. Problem Addressed Mitigates seasonal flooding of l~1ke Desire Dr. SE caused by road bed settling in the peat bog. Mitigates severe erosion, sediments deposited on County roads, and rlooding during times of high flows. Will prevent hlockage of culvert and 11,e accompanying flooding and erosion of Faiiwood Golf Course and mobile home park below. Project location is ideal because it addresses flows from a large residential area before they reach the steep, sensitive area nex:t to the Cedar River. Mitigates flooding of residence and sediment deposition on Jones Rd. A-3 Estimated Costs and Comments $73,000 $501,000 $87,000 $159,000 $163,000 3122 11 P:LC.APA Secure easement to wetland and con- s11·uct a containment berm and concrete weir at outlet. Project should be justified by a basin plan. Wetland rated #2. Biological assessment is needed to assure that this project does not decrease habitat values. Purchase ex1st1ng ponds on Fairv,.·ood Golf Course and expand to provide grcmer flow detention. Project is independently justifiable. Problem Addressed Addresses increased flows in Trih. 0304 and 0:104A from residential developments. Mitigates flooding and erosion downstream. A-4 Estimated Costs and Comments $371,000 $342,000 APPENDIX B CAPITAL IMPROVEMENT PROJECT RANKING LOWER CEDAR RIVER BASIN Prior to the Lowa Cedar River Basin field reconnaissance, 12 projects had been identified and · rated using the CIP selection criteria developed by the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Following the reconnaissance, 13 projects remain proposed for this area. They include eight new, previously unidentified and unrated projects. These displace seven previously selected projects, which were eliminated based on the consensus of the recon- naissance team. Projects were eliminated for several reasons: tv,,.·o sites were annexed by the city of Renton, two projects were found to be unnecessary, two sites were categorized as #1 wetlands (and are· ineligible), and one project was determined to be infeasible. The previous SWM capital improvement project list for the Lower Cedar River Basin had an esti- mated cost of $2,710,000, while the revised list increases to an estimated cost of $2,784,000. This 3 percent increase in estimated capital costs is due to the addition of projects after the reconnaissance. The following table summarizes the scores and costs for the CIPs proposed for the Lower Cedar River Basin. These projects were rated according to previously established SWM Program Citizen Advisory Committee criteria. The projects ranked below are those for which the first rating · question, ELEMENT 1: "GO/NO GO," could be answered affirmatively. Projects with scores of 100 .-: or higher can be considered now for merging into the "live" CIP list. RANK PROJECT NO. SCORE COST l 3122 103 $342,000 2 3118 90 87,000 3 3120 75 163,000 4 3109* 67 186,000 5 3121 65 371,000 6 3117 60 501,000 7 3115 60 361.000 8 3116 55 73,000 9 3114" 28 134,000 10 3111" 25 175,000 11 3112' 17 117,000 12 3119" 15 159.000 13 3105 12 115.000 TOTAL $2,784,000 • Projects propose.;t prior to the Reconnaissance Program B-1 •> /Iii' /ilii,i,s listed here are located on final display maps In the offices of Surface Water Management, Building and Land Pi!'V~lopment, and Basin Planning. Trib. & Collect. Item* River Mile Point Category Prop. Proj. 1 5 Geology 2 18 Geology 3 0299 4 Geology RM 2.6 4 0299 16 Geology RM 9.65 P: LC.AFC Existing Anticipated Conditions and Problems Conditions and Problems Recommendations Gullying and landslides in Continued erosion. Recompact fill, revegetate, uncom pacted fill in new and drain adequately. development near edge of steep hillslope. Small landslide has formed None (natural failure). None. debris flow (11/86). Sedimentation in yard of residence. Landslides in sedimentary Natural failure. None. rock in cutbanks adjacent to railroad. Drainage from residential Increasing erosion. Provide adequate R/0 to area is resulting in attenuate flows. gullying in swale. C-1 6 13 7 7 8 2 9 14 P: l.C.APC Geology Geology Geology Geology ,cc,-----,-----~rn>upf created extensive imper~ vious surfaces, resulting in channel scour, bank erosion, landslides, and sedimentation at mouth of basin. Residence overcome with sediment. Landslide terrain for sale by realtors. High risk for landslides, flooding (from springs). Large-scale landsides adjacent to Cedar River due to springs and cutting of toeslopes by streams. Appears to be natural. Gullying in valley wall, possibly from natural springs. Landslide debris flow from residence on SE 147th Pl., Renton. C-2 high erosion and sedimentation. Site of future mass erosion. Natural process. Unknown. Existing tension cracks indicate future instability. Rec9.mmendations. Develop R/D at horse farm to attenuate peak flows. See Project 3115. Prohibit development here. Notify Building and Land Development. Add area to SAMF. None. None. Revegetate hillslope with trees and shrubs. Trib. & Collect. Item River Mile Point IO 11 12 13 14 15 0299.JA RM .08 0300 RM .00-.40 0300 0300 RM 1.40 0302 RM .50 0302 RM .80-1.00 P: LC.APC 21 4 4 4 6 6 Category Prop. Proj. Hydrology 3116 Geology Hydrology 3119 Hydrology 3109 Geology Geology Existing Conditions and Problems Frequent flooding of county road caused by low road embankment. Extensive channel and bank erosion and numerous landslides due to development-related stormwater. Development-related peak flows have caused sig- nificant bank erosion. Collection point 4 has been nearly completely urbanized. Channel downcutting and bank erosion. Bank erosion (medium den- sity) at meanders and obstructions. C-3 Anticipated Conditions and Problems Road located on top of peat bog and will continue to settle, aggravating flooding problem. Problems will continue. Increased erosion on hillslopes below. Degradation of Trib. 0300 from RM .42 downstream. This section is very· steep and stisceptible to erosion. Will continue at same level or increase. Increasing erosion with increasing flow from devel~ opments. Recommendations Elevate the road 3-4' by filling on top of the present road embankment. Also stabilize embankment. Provide adequate R/D in uplands. (See Project 3119.) Construct detention dam in deep, channelized reach of Trib. 0300. Construct berm and standard control structure at outlet to Wetland 3120 in Cascade Park. Control storm flows from uplands. Provide adequate R/D in uplands as area develops. 16 17 18 19 20 21 ~ ~ RM .60-.80 0302 RM.35 0302 RM .45 0302 RM .50 0302 RM.90 P: LC./\PC 6 Geology 6 Geology 6 Habitat 6 Hydrology 6 Habitat 6 Habitat Existing Prop. Proi. Conditions and Problems Gully erosion from broken culverts. Severe gully erosion creating small valleys from daylight culverts. Stream channeled along golf course road. No overhead cover. No habi- tat diversity. Tributary drains down steep bluffs on north side of Cedar River, carrying debris and flooding Maplewood Golf Course. Water supply dam. Full barier to upstream migration. lmpoundment is filling with sediment. Severe gullying from right bank corregated metal pipe. Heavy sediment delivery to stream. C-4 Anticipated Condit ions and Problems None. Culvert has been repaired. Continued erosion. While fish now use this reach, lack of habitat will eventually reduce popula· tions. Problem will worsen as development upstream continues. As impoundment fills, storm- water will flood over bank. Stn1cture may fail. Will continue to erode until reaches till layer. Recommendations None. Tightline flows to main stem. Add habitat diversity ( e.g., structures, overhead vegetation). Gain easement to restore mean- ders, if possible. Construct detention dam upstream of golf course. Dredge pond and maintain it as sediment catch. -Tightline downslope. Add velocity attenuator at stream. 22 23 24 25 26 0302 RM 1.00 0302 RM 1.10 0303 0303 RM .25 mQJ RM .35 P: LC.APC 6 6 6 6 6 Existing Category Prop. Proj. Conditions and Problems Habitat Habitat Geology Habitat Habitat Trash in stream (auto, tires, appliances). Trash in stream. Water quality problem, unsightly. Extensive bank erosion in upper portions of tribu- tary. Habitat suitable for resi- dent fish. Sediment accu- mulating. Trash and litter in channel affecting water quality, causing erosion. C-5 Anticipated Conditions and Problems Area adjacent to corridor, will continue to collect trash and debris. Further worsening of water quality, sedimentation, erosion. Area adjacent to corridor, will continue to collect trash and debris. Further worsening of water quality. None. Sediments will eventually cover gravels. Habitat will become unsuitable for fish use. Further decreases in water quality. R~commendations Remove trash. Distribute educational materials to streamside residents. Cite violators, if problem persists. Remove trash. Distribute educational materials to streamside residents. Cite violators, if problem persists. Increase R/D volumes, slow release rate to nonerosive levels. Control stormwater volumes and discharge rates from developments. Manually clean gravels when necessary. Remove trash and litter. Distribute educational materials to streamside residents. Cite violators, if problem persists. 28 29 30 31 0304 RM 2.10 0304 RM 2.30 0304 RM 2.40 0304 RM .80 P: LC.APC 7 Habitat 8 Habitat 8 Hydrology 8 Habitat 7 Geology Problems L1ndslides contributing sediment to channel. Heary deposition in pools, at obstructions, even in riffles. Horses have access to stream, causing some bank deterioration and possibly affecting water quality. Flooding caused by failing RID at 176th St. & 146th Ave SE, Encroachment occurring along all boundaries of this headwater wetland. Several gullies due to daylight culverts; a few have recent landslides. C-6 Anticipated Conditions and Problems Sediment will continue to enter system until landslide stabilizes. Further decreases in water quality, bank erosion likely. Problem will continue until outlet structure js modified. Wetland likely to be reduced slowly until it is completely destroyed. Loss of storage, filtration, organic production, and wildlife habitat. Problem will continue. Recomme_p_dations Maintain riparian corridor with setbacks at least 50' from tops of banks. Encourage residents to fence channel back 15' from ordinary high-water mark. Limit access to livestock to one or tv.,,o points along stream. Problem referred to Main- tenance section of Surface Water Management Division. Require encroaching fills to be removed. Establish specific buffer around this wetland. Enforce sensitive areas ordinances and regula- tions. Tightline drainage. 32 33 34 36 37 0304 RM .00 0304 RM .20 0304 RM .62 0304 RM .80 0304A RM 1.30 P: LC.APC 7 7 7 7 7 Existing Caregorv Prop. Proi. Conditions and Problems Hal'1itc1t Habitat Habitat Habitat Hydrology 3102 Extensive riffle (to RM .15. Creek channeled. No woody debris, little bank vegetation. Steelhead, coho s.pawners here. Debris jam may be a partial migration barrier. Debris jam. Bed drops 3' over jam and sediment, forming anadromous barrier. Water turbid; oily sheen and odor present. Storm drains empty directly into stream. Existing forested wetland provides detention for Trib. 0304A and 0304 in heavily developed area. C-7 Anticipated Conditions and Problems Gravels risk becoming cemented. Few resting areas for upstream migrating fish. Debris will continue to accumulate. Channel will likely divert or jam will fail, releasing accumulated sediment. Debris will continue to accumulate. Channel will likely divert or jam will fail, releasing accumulated sediment. Water quality will continue to decline as runoff and waste enter stream. Additional storage could be utilized by constructing berm and weir at outlet. This could be done to atten- uate increased peak flows as upstream area develops. Recommendations Enhance habitat by addi- tion of woody debris in stream. Revegetate bank. Enhance pool/riffle ratio. Selectively remove debris to allow fish passage. Stabilize large woody debris. Selectively remove debris to allow fish passage. Stabilize large woody debris. Educate residents about how to maintain water quality. Mark storm drains with "Dump no oil" signs. Emphasize recycling of oil. Construct a proportional weir and berm at wetland outlet. Project could be used instead of Project 3107 to rpeserve the #1 rated wetland (where project would be built). -:o:<''l!:;~_;.r:;,P'~~f"'"""·c··:~ ·--;-,.~llli;,l:it•··· txisting Anticiputed rt~m ·· River Mile Point Category Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 38 0304A 18 Hydrology 3115 Runoff generated on top of Flooding will continue as Construct detention pond RM .40 bluffs on southwest side long as land use remains the al top of bluffs. of Cedar River is causing same on top of bluffs or Tightline drainage down severe bank erosion1 until mitigating measures bluffs, then channelize it flooding and debris flows are taken. Runoff origin• to an existing ditch onto several residences ates from highly compacted alongside SR 169. of valley floor. pastureland on uplands. • Prevent similar problems elsewhere with land use regulations, including provisions for preservation of vegetation buffers near tops of cliffs. 39 0305 10 Geology Extensive bank erosion, Susceptible to increases Attenuate high flows. partly due to subsurface with increasing storm flow. clay layer and landslide topography. 40 0305 10 Geology Local severe bank Problem will continue. Existing rock-filled RM 1.10 erosion. gabions are deflecting flow. 41 mos 10 Geology Extensive channel down-Continued erosion. Attenuate high flows with RM 2.10-cutting and bank erosion. adequate R/D. (RID 1.75 currently exists.) 42 0305 10 Geology Several gullies and asso-Erosion will continue. Tightline culverts. RM 2.15-ciated landslides due to 1.75 daylight culverts on steep slopes adjacent to chan- nels. P: LC.APC C-8 hem River Mile Point 43 44 45 46 47 0305 RM .20 0305 RM .35 0305 RM .00- .40 0305 RM .50 0305 RM .65 P: LC.APC JO 10 10 10 10 Existing Categorv Prop. Proj. Conditions and Problems Habitat Habitat Hydrology 3105 Habitat Habitat Madsen Creek in ditch along SE Jones Rd. Heavy silt; road runoff; water quality adversely affected. Creek in ditch along south side of SR 169. Heavy inputs of oils, anti- freezes, heavy metals, organic pollutants likely. Sand, silt from roadside (of SR 169) enters also. Section of Trib. 0305, RM .00-.40 is experiencing extensive flooding. Channelized along dri- veway; lacks habitat diversity. Driveway sedi- ments enter channel, and oil. placed on driveway enters stream. Channelized tributary lacks habitat di".'ersity, cover for salmonids. Gravels compacted. C-9 Anticipated Conditions and Problems Potential for fuel entry in- to creek. Further decreases in water quality can be ex- pected. Further decreases in water quality can be expected. Potential for autos to enter channel. L1ck of habitat. Flooding will continue, (See Appendix A, Project 3105,) Further siltation, water quality degradation can be anticipated. Lack of habitat precludes optimum salmonid use. Little salmonid use anticipated. Spawning and rearing success limited (unless reach is restored). '- Recommendations Acquire 30' easement away from roadside. Construct new stream channel. Acquire 30' easement away from roadside. Construct new stream channel. Construct and enhance 2200' of channel through undeveloped King County Park Land. Acquire easement; move creek from driveway 10-15'. Add meanders and habitat structures to increase diversity. Add structures to increase diversity in stream. Manually clean gravels by churning them. - 48 49 50 51 52 0305 RM .90 0305 RM .95 0305 RM 1.20 0305 RM 1.70 0306 RM .40 P: LC.APC C.itegorv 10 Hnbitat 10 Hahitat JO Habitat 10 Hahitat 10 Geology Existing Prop. Proj. Conditions and Problems Good spawning riffles occur here. V,-3" gravels, few fines, not compact. High flows are moving material, however. Severe bank cutting and erosion occurs here. Bed scouring evident. Reach subject to high, rapid flows. Much woody debris movement and numerous debris jams. Reach is subject to high, rapid flows. Channel erosion, bank failures, downcutting oc- curring. Reach subject to high, rapid flows. Failure of manhole during 11/86 storm has resulted in gully erosion. C-10 Anticipated Conditions and Problems Increased flows may cause gravel bar movement. Suitable gravels may be transported downstream to unusable areas for spawning salmonids. Further erosion/scouring can be expected. Channel deterioration will continue. Flows appear to be generated at developments. Debris jams will occur with greater frec1uency as flows increase. Sediments will build up and channel will divert. Further channel deteriora- tion may be expected. Silt, sand transport to mai·nstem will increase. Not applicaMe. Recommendations Control flows into system from developed areas upstream. If necessary, add bed controls to hold gravels or "vee" struc- tures to recruit them. Control high flows by increasing upper basin R/D facilities, lowering discharge rates to stream. Control upstream flows with greater R/D volume, lower discharge rates. Selectively remove debris. Increase R/0 capacity. Decrease discharge rates. Repair manhole. ~ River Mile Point 53 54 55 56 57 58 0306 RM .20 0306 RM .30 0306 RM .25 0306 RM .30-.45 0306 RM .30 ~ RM 1.30 P: LC.APC 10 10 11 JO 11 Existing Category Prop. Proj. Conditions and Problems Geology Geology Habitat Geology Hydrology 3118 Hydrology 3122 Channel downcutting, bank erosion and severnl landslides, due both from increased storm flows and development along edge. Undersized culvert in arti- ficial fill in golf course threatens to build lake and possibly overtop bank. Breach flood possible. Channel subject to high, damaging flows. Erosion evident. Downcutting, bank erosion and landslides. Trib. 0306 connects with large tributary at manhole here. Debris from 0306 clogs this manhole, causing severe erosion of Fainvood Golf Course. Existing small ponds on 0306A are overtopped and receive considerable silt during high flows. The ponds are located on Fairwood Golf Course. C-11 Anticipated Conditions and Problems Erosion will increase. Clay layer in valley makes area sensitive to landslides. Possible fill failure: Lake ponded behind culvert in in 1981 and threatened the fill. Further channel damage can be expected. Sediment transport downstream will continue, Will continue or increase in future. Problem will worsen as development upstream continues. Area upstream is developing quickly, thus worsening the problem. Recommendations Further increase in runoff should be attenuated; this is a sensitive channel. Enlarge the corregated metal pipe and/or construct adequate trash rack. Increase R/D capacity, decrease discharge rate. Attenuate storm flows. Replace existing pipes with larger diameter pipes (if downstream analysis allows for increased flows). Install new inlet struc- tures with trash racks. Acquire easements for ponds and additional area around ponds and construct detention pond. Location is ideal for addrcs.somg peak flows before they reach the sensitive Cedar Reiver bluffs. 59 60 61 62 63 0306A RM .25 0307 RM .10-.40 0307 RM .10-.60 0307 RM .30 0307 RM .60 P: LC.APC Prop. Proj. JJ 1-labitnt 12 Geology 12 Geology 12 Habitat 13 Hydrology and Problems Some usable habitat exists for resident salmonids. Water quality is poor. Channel subject to high flows. Extensive bank erosion at all meanders and obstruc- tions (trees, cars) due to increased flows from development. Stream eroding toes of slopes resulting in landslide failures. Stream channel pushed to one side of ravine for roadway. High energy system. Much bank cutting, sediment transport, debris inovc111ent. Area on top of bluffs near Trib. 0307 has excellent infiltrative capacity. C-12 Anticipated Conditions and Problems Further habitat deterioration likely. Channel erosion will increase. Increased erosion will result with increased flows. Increasing erosion with increasing flows. Erosion will worsen as stream flows increase. May threaten road bank at toe of slope. Infiltration sites should be used whenever possible. These would provide ground- water recharge. Recommendations Increase R/D capacities. Decrease discharge rat~s. Encourage use of 2-cell detention ponds, swales. Prohibit filling of existing wetlands, ponds in upper basin. Mitigate development- related high nows. Provide adequate RID. Mitigate development related high flows. Provide adequate R/D. Increase R/0 capacity at all delivery points. Reduce release rate below channel scour level. Construct retention faci- lities for new develop- ments in area at these sites. Trib. & Collect. Ctcm River Mile Point 64 65 66 67 68 0309 RM.IO 0310 RM .60 0310 RM .05 0310 RM I.SO 0310 RM .25 P: LC.APC 15 15 15 15 15 Categorv Habitat Geology Geology Geology Habitat Prop. Proj. 3120 Existing Conditions and Prc:ihlems Subject to heavy, rapid flows. Channel erosion, deposition bars migration, Sedimentation upstream from culvert due to debris and undersized culvert. New corregated metal pipe con- tinues to pass water through. Severe erosion below · culvert, severe sedimen- tation in residence yard, Road drainage forming gully adjacent to rand; road bed in danger. Corregated metal pipe is anadromous barrier. C-13 Anticipated Conditions and Problems Erosion, deposition will increase. Sediments will migrate downstream, creating a water quality problem. Continued sedimentation. Continued erosion and sedimentation. Continued erosion. Problem will continue. Recorn_mendations Control storm flows upstream. Control volume and discharge rates. See "Hydrologic and hydraulic characteristics" section in this report. Install energy dissipater below corregated metal pipe. Excavate channel through yard where original channel was located. Reroute drainage. Re[er problem to Roads Maintenance. Reinstall corregated metal pipe at or below bed level. 69 70 71 72 73 0310 RM .40 0310 RM .60 0311 RM 1.70 0314A RM .20 0314A/ 031413 RM .10-.40 P: LC.APC 15 15 13 16 16 Existing Categorv Prop. Proj. Conditions and Problems Hydrology 3120 Habitat Geology Hydrology 3117 Geology Existing channel draining off bluffs on north side of Cedar River, causing flooding of residences and debris flows onto Jones Rd. during peak flows. Corregated metal pipe outlet approximately 9' above bed level. Complete barrier to fish. Old culverts at bed level are plugged. Gully erosion in drainage swale due to outflow of wetland that partly seems to act as an R/0 facility. Severe erosion, flooding, damage to County and private roads from increased runoff from gravel pit operations on hillside. Inadequate R/D, plugged culvert caused by exten- sive channel and bank erosion and landslides. Water has cut a new channel. C-14 Anticipated Condition,;__ and Problems Frequency and severity of problem will worsen as development on bluffs increases. Problems will continue and worsen as outfall velocities will scour bed and banks. Upstream has recent (11/86) deposition up lo 4' deep. Continued accelerated ero- sion. Problem will be aggravated as area above develops. Not applicable. Recon,rnendations Construct detention pond on upstream side of Jones Rd. to trap sediments, and enhance 1,000' of creek from Jones Rd. to Cedar River. Remove new and old pipes; replace at lower level with oversized pipe with trash rack. If possible, enlarge R/D prior to its outlet in the wetland. Tightline drainage between detention ponds in gravel pit. Construct detention pond next to Jones Rd, to trap sediments. Constn1ct channel from Jones Rd. to Cedar River. See hydrology comment above. 74 75 76 77 River Mile Point Ql!1 RM 1.60 0320 RM 2.40 0318 RM .10 0382 RM .35 19 19 P: LC.APC Existing Category Prop. Proi. Conditions and Problems Hydrology 3111 Hydrology 3114 Habitat Habitat Francis L1ke is only hydraulic control for Trib. 0317. Existing forested wetland with large amount of un- utilized storage. Wetland currently detains flows on Trib. 0320. Snlmonid parr in many pools. L1rge pools up to 1.75' deep. Some deposi- tion in pools, behind obstn1ctions. Salmonid use apparent from carcasses. Sockeyc, Chinook spawners. Some sedimentation occurring. C-15 Anticipated Conditions and Problems Trib. 0317 flows through stt::ep area downstream of lake. If area around Francis L1ke develops, increased peak flows could cause severe damage to Trib. 0317 in the steep region. If Sllrrounding area urban- izes, this would be a good site to attenuate peak flows. Decrease in water quality with increasing develop- ment. Loss of habitat. Decrease in fish use. System is mostly in natural condition. As development increases, higher flows and worse water quality can be expected. Recommendntions Constnict proportional weir at outlet. Enhance 1,100' from Francis Lake to SE 184th St. Constn1ct containment berm and control stnicturc at outlet of wetland (if bio- logical analysis permits). Establish and maintain adequate buffers, 100' from ordinary high-water mark or 25' from top fo slope break, whichever is greater. Maintain adequate stream corridor buffers. Reduce discharge rates to pre-development levels. Prevent clearing, grading within buffers. 78 79 80 81 !!ill RM .50 0328 RM .70 0328 RM 1.10 1.40 ans RM 1.40 P: LC.J\PC 19 Geology 19 Habitat 19 Habitat 19 Hydrology 3112 Anticipated Problems Conditions and Problems Medium-density landslides None. and high-density bank erosion occurring due to natural causes. This indi- cates channel and valley sensitive to effects of development. (Sensitivity due to clay layer. Basin hosts some of best fish habitat in upper reaches.) Significant salmonid use throughout. Sockeye spnwners, carcasses present. Coho, steelhead parr in pools. Excellent habitat for spawning and rearing (a redd site). Much diversity •. most exemplary in basin. Channelized reach. Uniform channel, no habitat diver- sity. Heavy sand deposition. Little overhead canopy or bank vegetation. Lake Peterson is small, open-water wetland with a weir at outlet. C-16 Sedimentation from upstream reach possible. Adjacent development will likely reduce diversity and quality of habitat. May cause thermal problems as water temperatures rise. No useful habitat. Lake provides good peak flow attenuation and will become more important as upstream tributary area develops. Recommendations Limit development in the basin. Maintain leave strips adjacent to stream at least 100' from ordinary high-water mark. Restrict use/development within this streamside management zone. Restore stream habitat throughout: add structure, diversity, bank vegetation, and canopy. Cost should be borne by party(ies) who channelized this reach. Replace weir at outlet with a higher weir in order to gain additional storage. Surface Water Design Manual, Core Requirement #2 Basin: Cedar River Subbasin Name: Subbasin Number: -------------- Distance Observations of Field Inspector, Drainage Component Drainage Component from Site Existing Potential Resource Reviewer, or Symbol Type, Name, and Size Description Slope Discharge Problems Problems Resident Constrictions, under capacity, ponding. Type: sheet flow, swale, stream, overtopping, flooding, habitat or organism channel, pipe, pond; size, Drainage basin, vegetation, cover, destruction, scouring, bank sloughing, Tributary area, likelihood of problem, See Map diameter, surface area depth, type of sensitive area, volume % Ft. sedimentation, incision, other erosion overflow pathways~ potential impacts 1. Sheetflow off south Discharges to seasonal stream 5.15 0 -660 None Noted None Noted property line through forested area 2. Seasonal stream 2-foot bottom, 2 feet deep, 1: 1 1-2 660 -1,060 None Noted None Noted side slopes 3. Dispersed flow through Courses south 2 1,060 -1,260 None Noted None Noted thick brush and blackberries 4. Rockery wall Covered by blackberries -1,260 -1,265 None Noted None Noted 5. Broad channel may be Grass lined, 40-by 170-feet 1 1,265 -1,435 None Noted None Noted detention pond 6. 18-inch CMP Flows south from channel to I 1,435 -1,450 None Noted None Noted catch basin 7. 18-inch CMP Flows south from catch basin I 1,450 -1,490 None Noted None Noted to catch basin on south side of S.E. 144th Street 8. 18-inch CMP Flows west from catch basin to I 1,490 -1,612 None Noted None Noted catch basin 9. 18-inch CMP Flows west from catch basin to 1 1,612 -1,928 None Noted None Noted catch basin 10. 18-inch CMP Flows west from catch basin to I 1,928 -2,134 None Noted None Noted catch basin 11. 18-inch CMP Flows west across 1 2,134 -2,174 None Noted None Noted 160th Avenue S.E. 12. 18-inch CMP Flows west from catch basin to I 2,174 -2,304 None Noted None Noted catch basin 11778 003.doc See Map 13. 14. Type: sheet tlow. swale, stream, channel. pipe, pond: size, diameter, surface area 18-inch CMP IS-inch CMP e,-...,.,;,!i'a=t,=-~~~,•,• .,.,,~o'"':· · Dtainage Component Description Drainage basin, vegetation, cover, depth, type of sensitive area, volume Flows west from catch basin to catch basin Flows west catch basin to catch basin Slope % Discharge Ft. Existing Problems Potential Problems Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction. scouring, bank sloughing. sedimentation, incision, other erosion 2,304 -2,458 I None Noted None Noted 2,458 -2,632 I None Noted None Noted Observations of Fiel<I Inspector, Resource Reviewer, or. Resi4ent Tributary area. likelihood of problem. overflow pathways. potendal impacts 11778.003.doc TASK3 FIELD INSPECTION There were no problems observed during the resource review. Based on a review of the drainage complaints of the downstream drainage course, there were no existing constrictions or lack of capacity in the existing drainage system. 3.1 Conveyance System Nuisance Problems (Type 1) Conveyance system nuisance problems, in general, are defined as any existing or predicted flooding or erosion that does not constitute a severe flooding or erosion problem. Conveyance system nuisance problems are defined as flooding or erosion that results in the overflow of the constructed conveyance system for runoff events less than or equal to a IO-year event. Examples include inundation of a shoulder or lane of a roadway. Overflows collecting in yards or pastures, shallow flows across driveways, minor flooding in crawlspaces or unheated garages/outbuildings and minor erosion. Based on a review of the drainage complaints, there were no complaints associated with the downstream drainage course for this project site. However, there were complaints located on both sides of the downstream drainage course, to which this project site may contribute some runoff to under existing conditions; however, it was not likely. With the improvements of this project site, there is the potential that problems on both sides of the downstream drainage course may be helped somewhat by mitigating problems associated with those drainage complaints. Severe Erosion Problems (Type 2) Severe erosion problems are defined as downstream channels, ravines, or slopes with evidence of or potential for erosion/incision, sufficient to pose a sedimentation hazard to downstream conveyance systems or propose a landslide hazard by undercutting adjacent slopes. Severe erosion problems do not include roadway or minor ditch erosion. The sensitive areas folios indicated there were no erosion/sensitive areas in the downstream drainage course of the project site nor did the site visit find erosion problems evident anywhere along the downstream drainage course. Severe Flooding Problems (Type 3) Severe flooding problems can be caused by conveyance system overflows or the elevated water surfaces of ponds, lakes, wetlands, or closed depressions. Severe flooding problems warrant additional attention because they pose a significant threat either to health and safety or to public or private property. Neither the review of the drainage complaints nor the site visit noted any severe flooding problems in the downstream drainage course. Portions of the downstream drainage course investigated by the site visit and a review of the soils map indicates that the downstream drainage course occurs through till type soils. The field reconnaissance for this off-site analysis drainage report was conducted on the morning of October 27, 2005. The skies were partially overcast and the high temperature on this day was approximately 55 degrees. J 1778.003.doc TASK4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Runoff leaves the site by discharging off the southern property line of the site where it courses through thickly forested areas with alternating trails for access to different portions of the site, and tends to sheetflow through forested areas into a seasonal stream that courses south and southwest into a blackberry bush area, ultimately discharging to a large channel, which may be a detention pond, adjacent to S.E. 144th Street, then flows are collected in an 18-inch CMP and catch basin pipe conveyance system, where it is coursed along the southern side of S.E. 144th Street for several thousand feet in a westerly direction until over 0.5-mile from the project site where the off-site analysis was tenninated. The drainage complaints are located on the following pages of this report; however, none of them were located on the downstream drainage course followed for this project site. They were placed into this report for reference only and, therefore, there are no anticipated problems associated with the development of this project site. 11778.003.doc NOV. 3. 2005 8 • 3:JAM KING CO. WLRD NO. 5845 ' FILE COPY King County Water and Land Resources (WLR) Division 201 S Jackson St., Suite 600 Seattle, WA 98104-3855 Date: FAX Number of pages including cover sheet: _fZ._ To: e.&iJ0 tl;,e/JJ Pax:. .f,2:t-ef$/-.f'7J1.;? Phone:--------- From: Candi McKay, Eng Tech Il WLR Stonnwater Services Section Phone: 206-296·1900 Fax Number: 206-296..()192 IMPORTANT LEVEL 1 ANALYSIS NOTE: We do not send copies of certain complaint types $at are not relevant such as BCW, F1, FIR, FIH and WQA, and we do not send CL and LS types. See key below. Type S l, S2 and S3 will not be faxed due to size constraints. The following is a list of complaint types received by the Water and Land Resources Division Drainage Services Section. Complaint numbers beginning prior to 1990-XX:XX have been archived and are no · longer in our possession. They can still be re!rleved, if necessary, but will talce additional· time and may not be beneficial to your research due to their age, development which has occurred, etc. If you are interested in reviewing the actual complaints, they can be pnlled (time permitting) for your review. ;<:opies can be obtained for$ .15 per page, and $2.00 per page for plans. Keys: • . Type otlnye<tlgatlon Type of Problem . C AclioD Req11o,ic DCA DCW Businost"furC/ean Water DDM CCF Rosponscw lnquuy DBS "CL Claim DUl EH Enfo~tooB'old PTA ER llnfoo:<mcvt -cw . INQ FCC,FcR,FCS F&cility Complaiuu MMA 1'l SWM Fee lnquiiy MMF PlR. SWM Fee Review MMO · Fill SWM Fee on Hold. MMM •LS Lawmlt MNM .·-1r. RR FacilllyFng:i:neerlngReview MNW · !IDA Nc,jgbbod>ood 1>no1,'!l• A.ssullancO SWP , WQC Wator Quaiity Complan,t WQB ',°' WQ!! W•terQuality Bufo.-< . WQD .. , WQR Willet Quality Bngi,,eo,ing Review WQI ·:;:.WQA WlllelQualityA...Ut REM WQO WalerQu•lity-O<ho< Cliff : • .Sl.sl.SNJ ~ Sonia NWD Development/Construcdou Drainage .. MisoeUmP1l'IJs Dminllge-Erolion/llodimc1JlatioP • !Jralmgo-Landslidell!anh Movement Dtainage TechnlcaJ Assisuinc:e Dmlllase -Cleneal !Jlquity ---Aeslbetic.s Mam-·Floodmg Maino,"'""" -G<=ral Mointaw= -Mowm~ Maini..wtcc,-N«da M>lntenanee Maintenance-N~ouli W«:d$ SWM Fee QuOJ!iou, w.-Quallty-Be,t Mana,gemen< l'lllcticcs w-Qwillty-Dump!Jlg Watt:t Qwdily -lllk.U Connection SWM Fee -Remeasurement SWM Fee-Orant SWM Fee-New Discount · ·• O<t to Public Dlsclomre n:qui,=1> I • .lle<cipt of wd<= request fur documents 2. Roviow wt oppwvll by Prmecuting A<tomoy's offico I • 3. 2005 ~ ~.~~~ C0~1NG co.1.}~~ARTMENT OF PUBL4, WOR~g 5845 -p 2 . __ _..,., --SUR!?~ MANAGEMENT DIVISION COMPLAINT INVESTIGATION REPORT > Sketch-on reverse side: Yes Jlf No O Photos: Yes <01_ No o .. f""'\(N;rAity i sne:; Z.. "'Z-7-'1!. !)JTCNES o.>U ;u::,R,'!'14 :S-lt;c op SE' 1"1.s'../ PL ,v,,;u~ · ;u e-.vc(..o.;6-D • ·/Z-"1 CM,o ST//?ReO ovr 7c:J ~J"T 01=" MH 1/fS IZ.. ,,. CP Pt.oc,e-o ,(/b-<Jl,vsT ff 4:, 5/.l~,v /;u PUoT O Q. 6 .,,, o rF:s-e'T 013 S'e,eve:o. THe: 1Z, '' c.? Cc,,A.;T1A.Jue.s ;:e,,e._ /'. .;,, ..,.. '1: si.,, /Pt:a' 5't;C,T/0l\JS l U.v~ (fPlhTl'l~,1 TO 7J/€' 6<):, 1 • Te?eA1A.,,,<)i'e'.S e.c,,7 er ;!)1!/,U(}C-./Af/ AT 16'<l!O, PNO'R)@ ,1/0W-J l3X.J::... :s'v~ w1,J1c/./ -Y ff -;a-e,(;rf U/i.,C£ To -r/J JS: VJ\.../ ,:;;,.,I:::' P,/'1'5'_ ,{.Jo C-<Jrc.# ~/,U ozxs-to£vc':0 l,v ,r11s C4:.,dTlo/L/ DATE: 2.,-ZJ;-1 f // ~ J/·21 '1<, ~ u.,..- '· of action possible or taken by: Phone D Letter D Personal Contact D ::&c-:C'.;c; :::FPA/Sav Cla&ed: OK'd: __ _ NOV. 3. 2005 8:31AM KING CO. WLRD NO. 5845 P 3 ------~ ' q.~ F 1a:.t ~~N, =..,. ~j).J\ . \)J:_ R ~(ffi-~. -~..,..-.==-....:.....__:_=----------i:~+~" ......... __ 0 M SIGNED ~ SIGNED SEND PARU l AND 3 INTACT • PAl!T 3 Will BE RETURNm WITH REPLY. ·----[" ~ r 5E.. l 44 --n-i., 5T ---- DATE POlY PAK (50 SETS\ ,U,,(72 WLRD1----------NO. 5845-P. 4,--- ·N Scale~- oFF>c;f PIP& .]o1,vf JA) (j) King County Sud"ace Water Management Division Department o(Publfe Works Yeslu Building 400 Yesler Way -at>om .wo Seattle, WA 98104·263 7 (l!OG) 296-GS':t~ April 8, 1993 Mr. and Ms. John McKay 16404 Southeast 143rd Place Renton, WA 98055 RE: Notice of King County Code Violation -SWM-DIR 91-0188 ~O. 5845 P 5 Location: A portion of the northwest quarter (I/4) of Section 13, Township 23 North, Range 5 East, W.M. lying north.of and adjacent to southeast 143rd Place between 164th AvE!nue Southeast and 165th Pl ace Southeast. Lot 32, in the plat of Serena Park, in King County, Washjngton. Dear Mr. and Ms. McKay: During an inspection of the property referenced.above on October 25, 1992, representatives of the Surface Water Management Division of King County's Department of Public Works found the enclosing of the roadside drainage ditch with substandard materials in the County right-of-way without the required per- mits and approved plans. This is a violation of King County Code Title 9.04.130; A drainage facility or construction site which: Adverse1y affects safety and operation of County right-of-way, utilities, or other County owne~ and maintained property; ·a11d Results in dirt, mud, water, and/or ice on the roadway. This is also a violation of King County Code Title 14.24.010; Road construction work which does not comply with King County Road Standards; and Title 14.28.020; Work within King County right-of-way without a permit and approved plans. You are therefore requested to contact De1ite Ko1er, Drainage Investigation and Regulation Unit Engineer, at 296-1986 to discuss the correc- -tive work required to resolve these code violations. No drainage facilities, natural or manmade, may be altered or obstructed without prior permission. If you do not contact this Division within 20 days from the date of this letter, we may initiate appropriate enforcement action. This 1etter is not a Notice and Order as described in King County Code Title 23; however, the exis- tence of the violation noted above may subject you-to civil penalties.and other methods of enforcement authorized by King County Code Tttle 23. ':;. -;,.1.,.- 8:31AM KlNG CO. WLRD .NO. 5845~P. 6 ··--··--'· ... -. {(Jj.] J' Mr. and Ms. John McKay : April 8, 1993 page Two Your timely resolution of this violation will be appreciated. If you have any questions concerning this matter, please call Delite Koler, Drainage f,Jnvestigation and Regulation Unit Engineer, at 296-1986. ~·,· Sfsincerely, fµµ /¥J!A~,/ "\Qurt W. Crawford, P.E. JtSilpervi Sing Engineer, Ora i nage l:IMestigation and Regulation Unit -ti.-:• Chuck Kleeberg; Director, Department of Development and Environmental Services ATTN: Gary Kohler, Manager, Land Use Services Division Louis J. Haff, County Road Engineer ATTN: Tony Ledbetter, Supervisor, Maintenance Section, Division 4 Jim Kramer, Manager, Surface Water Management Division ATTN: Ken Guy, Assistant Manager Dick Thiel, Manager, Engineering and Environmental Services Section Larry Gettle, Senior Engineer, Drainage Investigation and Regulation Unit Delite Koler, Engineer NOV 3. 2005 8:31AM KING CO. WLRD NO. 5845 P 7 0/111 efil?d f66I '8 U~dlf Ae~jW uqor ·sH pue ·;w ' rongcounty Surface Wate,-Management Divlsion Depar<meni of Pubhc 1'brks 700Iiftl,;1.v,nue Suite UOO ~1tle1 ~ 961~ (,006) 298-65l9 (l!IJG) 296-019,2 FJ\lt February 11, 1994 Mr. and Mrs. John McKay 16404 Southeast 143rd Place Renton, WA 98055 RE: Notice of King County Code Violation -SWM -DIR 91~0188 Second Notice Location: A portion of the northwest quarter (1/4) of Section 13, Town- ship 23 North, Range 5 .East, W.M., lying north of and adjacent to Southeast 143rd Place between 164th Avenue Southeast and 165th Place Southeast. Lot 32 in the plat of Serena Park, in Kj.ng County, Washington. Dear Mr. and Mrs, McKay: .During an inspection of the property referenced above on February l, 1994, representatives of the King County Surface Water Management Division found that the substandard pipe that was installed in the right-of-way in front of your lot and tied into the drainage system has not been removed. This substandard installation is on the south and west sides of your lot. The fill that was placed in the roadside ditch also has not been removed and the ditch restored to the original design specifications. This is a violation of King County Code Title 9,04.130: A drainage facility or constructfon site which: Adversely affects safety and operation of County right-of-way, utilities, or other County owned/maintained property: Adversely affects other drainage facilities; and Results in dirt, mud, and/or ice on the roadway. This.is also a violation of King County Code Title 14.24.010: Road construction work which does not· comply with King County road standards. t You are therefore requested to contact De lite Kol er, Drainage Investigation and :Regulation Unit Engineer, at 296-1986 to discuss the corrective wol'k re.quired :to resolve these code violations. No drainage facilities, natural or manmade, ;may be altered or obstructed without prior-permission. If you do not contact this Division within 20 days from the date of this letter, we may initiate propriate enforcement action. This letter is not. a Notice. and Order as escribed in King County Code Title 23; however, the existence of the violation Oted above may subject you to civil penalties and other methods of enforcement· Uthorhed by King County Code Tit 1 e 23. NOY, 3. 2005 8:31AM KING CO. WLRD Mr. and Mrs. John McKay February 11, 1994 Page Two NO. 5845 P 8 Thank you for your attention to this matter. Your timely resolution of this violation will be appreciated. If you have any questions, please call Delite Koler. s;;;ereL/J, r-.e:!A/V ~ !raw;ord, P.E. Supervising Engineer, rainage Investigation and Regulation Unit CC:DK:ss C/W'P6: L T24 cc: .Gary Kohler, Manager, land Use Services Division Lou Haff, County Road Engineer, Roads and Engineering Division AI!!'!: Rod Matsuno, Operations Manager, Maintenance Section Tony Ledbetter, Maintenance Supervisor, Division 4 Jim Kramer, Manager, Surface Water Management Division · AITN: Ken Guy, Assistant Manager · Dick Thiel, Manager, Engineering and Environmental Services Section · Larry Gettle, Senior Engineer, Drainage Investigation and Unit f , Engineer ~ ' 3 2005 8:31AM KING CO. WLRD .. NO. 5845 . . KING COUNTY SURFACE WATER MANAGEMENT DIVISION DRAINAGE INVESTIGATION REPORT Page 1: INVESTIGATION"FlEQUEST Type c__.,,. Received by: Date:;q;&ft~ ·O~dby; [)~FileNo.9t,-/7;;)'j ; Received from: (Please print plainly for t.03nning). (Day) (Ev•) --=.r.!1k.~'fl.//2e_=,~./..Lfi...L./~i.L<Kl...L.JLJ~) ______ PHONE c?JJ'-fl5t!?'I __ _ ,~/!/..t..J.'2:Z,,.,Qk.,L.(p..,· '--_,,/ln\,.L<~i-'-dv~a=,!P/7=__,_()L..,,,_Zedl.<-City ii.~ State_ Zip 1,&5j ··• cation of problem. if different: --~ .Aaa,a_,~ ~ ~ ~ Ju,a, chm/--<U__; ~ ~~ --bJ ~ 0:l!Yl. ~ cddJ (2, ~I LotNo: 30 Block No: No Field Investigation Needed --- .d:3, R:; _a;:- ·;, S T , R ·. BasinW Council Dist /is, Charge No: ;'£: Citizen notified on/C:::,;../7f'-by ·_phone_·. letter.~ fn person • Q,:Lc__ 0 '"' .s,A'... ~f ~frr/1-4-/or.S L,':S. I c.-1 .~~ Turned to ___ on-----by __ _ OR: No further action recommended becaus, ency has beEn notified: •· has been corrected. -~~"N;-.:-o-=p-=ro:.:b.:Je-:-m-h:-a:-cs'b-e-en"""'i~de-n"ti"'"fie-d'""". -----aPccri,...or"'"'i,...nv-e....,st7--lg-au-·o-n_a_d_dr_es_s-es-pr....,oblem: -See File # ' · rob/em • NDAP will not consider because: .. _x'Water originates onsite and/or on neighboring parcel '; _ LocatJon is outside SWM Service Area. ·,ED; __f!_;_jf; !iL by; ::Ji, '.. 11/'f"rPRO./!; _ Other (Specify); NOY. 3. 2005 8 32AM KING CO. WLRD Klug County Department ofNalnral Resources Surface Water Management DRAINAGE INVESTIGATION REPORT FlELl> INVESTIGATION FILE N0~1724 NAME: GENE l!IVAS ADDRESS: 14206 164Tll AVEB!l PHONE22l!-8524 MAlNTENANCB 4 NO. 5845 P 10 ··~ ·------=c.. DATE 10.17-96 INITIALS DCD \ . •· ,ULS OF INVESTIGATION: I meet with Gene Rivllll at his home to discuss his concerns about a . ·uage problem in bis backyard. Mr, Rivas property abuts up to a parcel of property o~ed by King ty Parks that is undeveloped. Mr. Rivas property is saturated from the runoff from the Parks · perty. This water then get.s under the Rivas house and into the driveway and into a catchbasin in the ,, .t of the Rivllll property.· I explained to Mr. Rivas that he shooJd contact a contractor lo see about . . g a French drain system. I said I would sep.d a copy of the contractors list and a F?ench drain . ..: SURFACE FLOws· . . • SATURATED ARE.A I<- ~ • YARDDRAIN -. -.. ·t-, .. · .. ·--..· 164nIAVESE NOV. 3. 2005 8:32AM KING CO. WLRD NO. 5845 P 11 ; , ' . \ ~ ·· ..... +---· · · ... ) .. ,~ioHe eou~ suRFACE WATER MANAGEMENT oiv1sie14 ···[).cD ~ . Typa , · DR.A.ffiAGE INVESTIGATION RE~ORT · Page· 1;-lNVESTIGATIONrlEQUE~ OK'd by: FIia ·No. Lot No: · / / . Blo~No: . ; -t!J···· Z-3 · ~ Parcel No. 72. -; ?76 -6//6 .. s ~~ ---· Basin j_,C!J, . CounoiJ tllst / :2._ Charge No:. ___ _ Th.Bros: New657tf3 . otd 215 FG:> ,.Fi: Citizen notified on1.-J..0-9"1 by· ..k'.'._ phon·e _ letter _ In person . . ·•_P~':"-~.~-~ ~ i;,u.4, ~-~ ~ ···"*~~~-. · .. ·. /Jb{J-,R_ c/-~'7) /I.Ad" ~ . Turned to K ' on ) FI/: 7 7. b; . F ff'/ OR: No further action recommended becaL ' . eney has been notified: -___;~~-.,..............,.....---,-,---=-.,.......---'-.,...,....--,---,,,.....,,-...,..,.---, has been .corrected. _ No problem has been Identified. _ Prior Investigation address.es proble . ~~# • /J:>roblem -NDAP will nor crms/der because: l _ Water originates onslte and/or on neighboring parcel '·. --a. locatio!1/s outside SWM Servlo(Area. .fED: .1CLJ41~ by:.p..· ~ ...:..... Other {Specify): J · . . t /(..,]75 /· NOV 3. 2005 8: 32AM KI NG CO. WLRD Complaint 97-206; Don Gr"3g, 16046 SE 142"" Pl., Renton Investigated b.)" Sean Groom on O 1114/97 NO. 5845 P. 12 ·-·---··~--~--------·--- Don Gregg has lived at the above referenced location since the early 60~ (his house was second built in the development). S1llface storm water flows began flooding his garage approximately five years ago. At his own expense at that time he brought a back hoc in to cut a drainage· ditch along the back side of his property. This open trench provides relief during most precipitation events swface water moves around his property. Stomi water does breech the top occasionally. The ditch fills sediments up and he clears the ditch of debris th.at floats down and reduces flow. He walks the drainage dirch during storm events (he wasn't around for the last stonn event) to observe its functionality as a precaution as well. Be w.:mts the drainage to. continue doWII 160"' Ave SE insread or a conveyroice system around his and neighbor's property. Apparently, as development north of his property has increased additional runoff is concentrated into the drainage along 160"' Ave SE and subsequently runs to his property. S.E. Standing water, runolffrom 160"' Ave SE discharges into this area. Low perw!ation. Gregg said the land can't be developed because they don't have the percolation for Infiltration of septic systems. ~rt.I} ...... SE 142nd Place -,. NOV. 3.2005 8:32AM NEXG!lBOlUIOOll llRAUIAGl'l llSSXS'l'Al'l"Cl!l PROGRAM (RDAP) COMPLAill'r EVllL~ION MEMO DATE, 3-19-97 To, FILE FROM: Al.an Meyera RE: NDAP EVALUATION FOR COMPI.AIN'I' NO. 16046 SE 142Nll PLACE RXN'l'ON 97-0206 GIIAGG 235-0168 CClMPI.i.INT CHRONOLOGY, ORIGINAL FIELD INV FIELD EVAL. l-10-97 1-14-97 3-7-97 BY SEAN GROOM BY ALAN MEYERS. OLD FILES: NONE BAC!tGROllND: Please eee the attached drainage complaint investigation report dated l-14-97 by sean Groom. FDlllll'IGS: Since the probl""' meets all of the NUAP project criteria listed below, it gua.J.ifies for and has been investigated under the NllAP program. • The'problem site is within the SWM service area and does not involve ·a King County (KC) code violation. • The problem site shows evidence of or reported localized flooding, erosion and/or sedimentation within the off road drainage system on private residential and/or cOl!Wlercial property due in part to later upstream devel.opment. • The problem is caused by surface water from more than one adjoining property. SOILS: According to the KC soils map, the site ia located in the following aoil association, AUJERWOOD ASSOCIATION: Moderately well drained undulating to hilly soils that have dense, very slowly permeable glacial till. at a depth of 20 to 40 inches; on uplands and terraces. ,;" I met With· Mr. Gragg on March 7th and toured his property. As :,: devel.opment continue,. in the approximate 60 acre dra.inage basin north of ·:liis property, more drainage water has been routed south into the pond ·;::located just NW of his pl:'operty whioh then drains ea.et and south around '{the edgi, of his property. l '. . ' 0::/1010~ NOV. 3 2005 8 32AM KING CO. WI_RD NO. 5845 P 14 Be requested that the drainage flowing eouth along the east aide of 160th Avenue SE be rerouted straight aouth along the east side of 160th past SE 142nd Place rather than the current route whiQh flows east and south around his property. Mr. Gragg stated that severa1 long term residents have told him the drainage used to flow straight south along the weet and east sides of 160th all the way down to SE 144th. I stated that may be true but the existing drainage pattern is o1d and cannot be revised because it is considered tbe estab1ished drainage pattern for his area. I reviewed hie and hie two neighbor's drainage related impacts and scored the problem at 14 with his garage and septic system i.n\Pacts and yard damage .to two properties, Although the laet few years have been especia1ly wet and bad, I rated the event frequency at 10 or once every 2-5 years which is my estimate of the frequency of how often his septic system will be severely impacted over the long term. Mr. Gragg stated that his pumped effluent septic system has work"'1 fine for the first 15 years. HoweYer, he has burned up four pumps within the last three years due to the increased groundwater flows into his septic tank/<irainfield area. From his wet/dry season observations, he ia convinced that most of the groundwater comes from the drainage ditch located just above hie drainfisld. We reviewed ways of protecting his septic draintield from the movement of groundwater from the uphill pond and drainage ditch. We discussed ways to seal the earthen ditQh itself using a plastic liner or a large half round or full pipe eectiona along about 50 feet of ditch above his drainfield. I pointed out that considerable groundwater may still flow from north to south below the ditch section so that sealing the ditch may not solve the problem, Depending on the depth to hardpan, an iiPpervious vertical layer of plastic or bentonite slurry located uphill of his drainfield between his drainfield and the ditch would probab1y be the easiest and most effective solution to this problem. This impervious layer would run from the ground surface down to the hardpan layer where it would be keyed dowo into the hardpan layer. Because such a layer would restrict the flow of ground water, higher groundwater levels might result in this part of Gragg's yard with more groundwater surfacing du~ing tbe·wet season eapecially near each end of such an impervious wall ~eeu1ting in more wet season surface wa~er seepage/flows and ioy conditions on port;lone of Mr. Gragg'a driveway. For any work this close to the drainfield, any yard draic or impervious facility of this kind would have to be reviewed and approved by the King county Eealth Department (~ayne·Olsen at 296-9737). 2 NOV. 3.2005 8:32AM KING CO. WLRD NO. 58<15 P 15 ' ·-~.~- OPTIONS AND DISCOSSIQJI' Hr. Gragg is concerned about continuing upstream ~evelopment which typically results in more surface water fl._ws through his drainage ditch and occasionally into hie yard. I explained that for larger dtovelopments where more than 5,000 square feet of impervious surfaces are constructed, the developer's enginesr is only required to review the drainage system's capacity·up to one quarter of a mile downstream from the proposed plat•s outlet point. ?or single homesites, there is no:rmally no downstream analysis required since there is usually less than 5,000 square feet of new impi.rviolls surfaces constructed. I suggested that Mr. Gragg look for Development Signe along 160th north of his home. When he sees new signs, he can attend public hearings and write letters expressing his concerns and outlining his drainage impacts. DIPAC'.r SCOIUS = 140 PROPOSED SOLUTION: No solution to this drainage problem was identified. Mr. Gragg requested that we c1ea.n out his drainage ditch. We offered to clean out part of his ditch if our contractor can get the necessary equipment from Gragg's driveway into the ditch~ NO PRIORITY SCORJ;; WAS CALCIJLATml SllfCl!l NO SOLUTION WAS lDENTIF'IED 3 ..,., __ ~-·-· -~-~--- NOV. 3. 2005. 8:32AM KING CO. WLRD NO. 5845 P 16 .. .. · Kl.NG COUNTY WATER AND LAND RESOURCES DIVISION . D:RAINAGE INvESTIGATION REPORT lNVBSTIGATIONREQUEST · Date: s(~6S1K'dby: FILENO, 2005 -())-.'t-Q ···· Received from: l. AME: ~ . I t.)W, 1 }}1c90PHONE __ (D_ay_)_'--(.~~~) _ . . I (Eve) ,._( _ _,) ~-~---------'----'--~City ______ . State Zip __ _ !¥~Sc }:\ON OF PROBLEM, IF DIFFERENT· :y Permission Granted D Call First (W-0uld Like To B<> Present) D · . - CJ;~'k) ~-Wl· -.'~ (/ ltfN11 ~U6~~ FfL: COPY o~osss Lot No: Block No: T .· . R. Basin' ~kl?_ Coll!lcil District /r& City ___ Charge No .. ______ _ Ci~ notified on ------by: __ phone __ letter ~ in person Twnedto on / I . by __ OR: No further action recommended becaus~: . encyh¥ been notified:. _______________ ~----~--- ' ~ bee,o. corrected. _ No problem has been identified. _ Prior investigation addresses problem: . ">..· • . . SEEFILE# · . ' , .. blem -ND.AP will not consider because: • Water originates ons1te and/or on neighboring parcel. __ Other (Specify): I I By: __ _ NG'/. 3.20051 8:32AM KING CO. WLRD N0.5845 KING CoUNTYWATERAND LAND RESOURCES DMSION DRAINAGE INVESTIGATION.REPORT INVESTIGATION REQUEST P. I 7 T,ype C Date: 8 q 6 0 OK'd b : FILENO, 2005 -d!3~ (Day) ("iOb} JJ(evlG k,;1.LEfZ PHONE 2--10 -3 73 / (Eve) .,__( _ ___,_) I( C.. :»OT -.[µf,/NEtfltlJ& City State. __ Zip __ _ •·•·· :uoNOFPRO~LEM,lFDJFFERENT: nR.TtON:5 tF JfoZ. lw.:S{ f lkf )uc si;,>Jol"{, &F 5~ 10 sr. ' s Permission Grm,ted D . Cllll First (Would Like To Be Present) D 1 . . Lot No: ' . ' BiockNo: · ed . T 7 . R 'ParcelNo. /'(S?&OO/</S Kron'f'// Th.Bros: New GS7 3·3 Basin /:(Jt Council District I J .. City ___ Charge No •. _______ _ Citizell notified on ------by: __ phone __ letter __ in person· Turned to on --cl __ /~-bY.--OR; No further action recomtnended because: cybas been notified: _______________________ _ . has bee.n corrected. _ No problem has been identified. _._ Prior investigation addresses problem: ,; · SEEFlLE#. __ _ /:Oblem -NDAP will not consider because, ,, · Water originates onsite and/or on neigliborin.g parcel. __ Other (Specify): I I By: __ _ 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology The entire 9.91 acres of new development is considered till forest for pre-developed condition. However, there is an existing single-family residence located in the northwest corner of the project site, which will be demolished with this development. There is a small amount of impervious surface associated with this single-family residence that contributes runoff to the downstream drainage course under existing conditions. However, this site is modeled entirely as till forest for the pre-developed condition. The flow control facility will be located at the southwest comer of the project site and will discharge much as it does under existing conditions after being dispersed at the southwest corner of the project site. B. Developed Site Hydrology Under developed conditions, to determine the total amount of impervious surface contributing runoff to the pond, all of the streets and sidewalks were considered impervious surfaces and an area determined for all of them. Since this project site is zoned R-4, which requires that the maximum amount of impervious surface per lot be 55 percent, the total acreage of lots was multiplied by 55 percent to determine an impervious area for all of the lots. In addition, the wet/detention pond was considered to be impervious surface for the portion of the surface area of the wet/detention pond that is dead storage. This yielded a total impervious area of 6.37 acres with the remainder of the area as till grass (3.54 acres), totaling 9.91 acres of development. No Flow Control BMPs are included in these areas of development so the actual detention volume computed would be less in the final design when the Flow Control BMPs are applied to the project site for each lot. C. Performance Standards The Area-Specific Flow Control Standard required for this project site is Level 2 Flow Control, a.k.a. the Conservation Flow Control Standard. The applicable conveyance system capacity standard was mentioned in the Conditions and Requirements Summary, which is to size the on-site conveyance system by the Rational method utilizing an initial time of concentration of 6.3 minutes and a Manning's "n" value of 0.014 with the 25-year precipitation. The Area-Specific Water Quality Treatments Menu followed for this project was the Basic Water Quality Menu, and the item selected from this menu is to use the wet pond located below the live storage in the wet/detention pond. D. Flow Control System Please see the illustrative sketch of the flow control facility located the following pages of the report, as well as the calculations provided for sizing the flow control system for this project. E. Water Quality System Please refer to the same illustrative sketch referenced above, which is provided on the following pages of this report for the wet pond located below the live storage in the wet/detention pond provided with this development. In addition, the calculations for sizing the wet pond are included herewith. 11778.005.doc [JPJhep] 'vllVIIVO !:10::1 N'vld 30VNIVl:10 ONV S311:IO!:ld ONV OVO!:I A!:IVNl~ll31:ld \ "'1111 -OQ',O+tl 'Vt$ S0086 VM '3M31138 001 .31.S 'l.331:JJ.S Hl8 ·:rN OZCZl 'dl:JOO lN3~dOl31\30 SS)I 0·19; t0+1"1 • 'll5 !old -8 lhOII JO \ im,?S¥litit 0'6> j ' " !I \ I \ I I I I , ; i c__). \ \ ~1~ ~~ ~ -- ! .. i~I§ r «· 1·e,, ". ~ t L>>" m I ' '- ' ~ ~ ~-;~, • ~ 'Ott <( t \ ·~· ! ·- ! • tt ~ ~-~t ·,tt ' ' 611» i I -,- I I ~ t ~~;~ i• l •I• ,o~w•A .ot-.l IDJUO,~OH ·010,, ~ I ~·· I / I I / ' ' ·; / / ./ ti ~ /Q.,~o}::-1101-m) . Ij;~ i• ..-:iiltltn •1•a S3~1Al,3S l'1"JN311NO~I/\N3 "ONLGtJ:!l"IS ?,; '~NINN'llC Qtf(l 'ONllf.BNIOt.J llfll::l •. -.nm-?"'o.Jc!lty ' . -sv--P•~,.4~ XVJ l'ilL8-l<;l(<;lt) l i·.;, UC:9-LSC:(SZ:l') ~ Ji -.:,s-----~ Z.£096 VM '!N]>I -illr pou61HO HlnOS 3nN3M ONZL S \ Z8 \ "/)y140+ , • ·~s, tt H•• • I n~, I i 8 ... , ' I I ti"l!St 8 ! o·&' ! ' env+t1 -vis "f ~ JO ' IIOIµ~ i , . • ij"i9P ~ ID ' Cl ·- \"11l,. 8 .. ~9· • ~ i 0 ij"69t 0 . -8 ~1 6"\L• ! ~; J ' i i t 1, _l ____ ' I~ II-~ '· !T -. -~1 l ~~ II' i~ :i ' ii ii i! ,, I' !! ,I " ·, __ J __ ' ' .. I ·-ii~ !,, 1,· -,' Iii ' , DETENTION POND SIZING CRITERIA No Flow Control BMPs were applied for this initial sizing; however, they will be utilized with the final design. Zoning = R4 The maximum allowed impervious coverage per lot = 55 percent Roadway and Sidewalk = 1.63 ac. impervious Pond = 0.19 ac. impervious Total impervious = 6.37 ac. till grass 3.54 ac. 8.28 acres of lots x 0.55 = 4.55 acres impervious 11778.005.doc [JPJ/tep) V, = V, = V, = vb = SIZE THE BASIC WET PONO [ 0.9 A, + 0.25 A1,] 0.039 [(0.9)(6.37) + (0.25)(3.54)] (0.039)(43,560) I 1,243 cu. ft. 3 V, = 33,729 cu. ft. 11778.005.doc [JPJ/lep] ·,, ! .-: .. , \ (( \ ' \ l J ) j I Ii J ( ,)' / l ·l~ , ) ' ' /-' ,____ ·, I ··'""".· I / /~ ~\ .,/ ( {c. "..:,_ / /, r I ,,,,,. I I._, /' l .. '' ---'\ ~-,,:- ' "-.,-. : ,, \~ [; /T .,.---'" " s \ \ r ' .l • ~-) ,, Ol '·-',.. . \ ~f.• !~{n!(]'! ..... r---,....,.,,..,,.,,..."'- --· + ..--) -·; L , .. .,,., I -Prefem,d Alternative Green Rout.. Altemative = Bellavuee/ssaquah Plpollne = SPU T111nsml5:!lon Line = TW Transmission Une i t3 Propoaed Locatnn ofRachlortnallon Fa~llny ~ Munlclpal Boundary ""' Stri,am/Rlver Hlgh .. ay Secondary Road _...,.._ .... _,,_,_ ... _. __ .. ,-, I , ' ' J • ' "-d ' ' ~~ MAIN FILE COPY Squak Mountain Cedar HUia Landfflt \ I I l c_J ' ' RGURE2-2 Tacoma-Cascade Pipeline (TCP) Preferred and Green Route Alternatives Legend Cvntral S.11m111>t Ai.matlvel!I Green Ntemative BlueAlklmahve Light Blue Opton Red Alternative Black Allemabve North SagmantAltamatlvH • LDww hach J -Blue Allema1ive Rad Option Green Altemellve Ro,seAltemstive -Plum Altematlve Lime AltemelM! Lime Option = 8eilewa--l5saquBh Pipeline = SPU Trfltlsm!ssion Line = TW Transmission Line ,::J Municipal Boundary "'" Slreem!River Highway Sacondary Road ·~ ""'R;P_ .. _ .. _._.~ tiJ{, • ' ~1 J- L--.i .. Cougar MolA'llaln " ---, ' ._ ______ , ' ,, / ( ( \ ,; :] \:-, ' I f .. --, . Squak Mountain Cedar HINs Landflll L ... J RGUREZ.1 Tacoma-Cascade Pipeline (TCP) Route Alternatives Described in the Route Study Reporls Pl'eferred Altf:l"nalive Green Route Altemative ~ Pl'o~d Location of R&chlc..-i natbn Focility Tacoma -Cascade Pipeline (TCP) Preferred and Gr een Route Alternatives (Aerlal Photo) Legend Greoo Rouce A.lkffiabve Tacoma-Cascade Pipeline (TCP) Preferred and Green Route Alternatives (Aerial Photo) , Kl.J..llrr"_,n • 1 ~ r ;. ~ xu.»• J,....c ,.r II ~ < ~ ~La.I, .. ~ t(,t~l ~f ... ~ -· ' ~t ,.,m ~, t- • • e \ ' • ~ " ,, ~ ' Wll.tlt~!.t ''. ,..,i .,lf ~ :1 ,¥".,·r·,., t ~ II 'i % .. ~··· ~ ·~. 1,.-;::-:.0 ~ . , ... }"~"' "', "'..-(' ~- + ... '•..., ~ ' 1 .. 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Grcundw1tM Source, Gr: .. ~A -,'f,•• 1.t·:,.;U '"°"'' ::.1'::o:-,'Y:' t •' County Bound ary X llounla ln Puk• I Hi gh••Y• j'I Kina Coun1y W•tu R.r,ourto 1 -.... l nventnry ArHs Streets I 1t ,;,~· /."!~.>· ~=~~ i Puc tis I O Orou nd.,alrr Manag,mrnt Arns l~kts -1nd Lar~ Rivcr1 Legend Str•am1 Ar.a• SuHopt1bie to Ground,.•trr Contam ination 'Axs ... r 11 1;!' /'f Jncorpor1~d Ania The lntonnricnwd.ldiedon N• mapt\61 bMn oompiladt,y ~ Co,,inty ..rt from •v&nlilyof eou,wa and l&-.tJilid lo chlroe ~ not.o. klngeo::;,1ymab• N> ,-ptffel\t.H ona 0t: wenantiiu,•lfllt• .. q,~ M10 aco.uacy. ~ ... i;;;c;.-., Of iiii•IO !he u • of uoh infotm41l!On ftu ~'-not 10~ to, 1,1,fie •• • .,,..,,.W' Pl'"~ ~ Couity an.a not bit IWl1" tot .,.., get,,e,'11 ~-not ,..,_ lnCl(WIUII, °" con-.:JVOl1t,M <Jetn~ tr'l()lu()ng. wt M: lin-.ttea '°'· IOll ,.,,,.111,,,,e4 or io.i proa1a ,...nng ltQf'n lha ..... cw "MUN cf aw 11'1~ coola!Md on r,i., map My ..a. ol ri.. .,...., or NOtmall(Wl Qn IP"f m.p • 1 M'I protwbla.d .xoepl tl')' M1UM'i ~,m1...o,n ol Klrlg Oo,.,nl)' .,._ Kirlg Col.anty o.~ ll/l e.'2007 Sou10111 ~ Coun~ IMAP • ~tar PTog,arn {hl1P N-ff'oefl()ll;t; ~t&IJrr,IAP) iMAP Legend Gmund\lf l 1M Sau~e5 Sh•m• ·1·11 ·..::, ~~:.i:: ... 'if:·; Crilital Aquiftr Rcthar9" Aru Li-:::1~1ji t'f~ ~ ~::t~-:·,·1 ... :•.,, 'jf,'!!<f',/f;:,1, ',;;c,n~·,·' .. :, ....... 'l ...... i /•' Courrty Boundary C::t.-:i,:,·,·; .:; ~ ~ I " •,, .. ·-....... :i; x Mo unt.in Peaks Hlgh ,rays j/ lntor poratrd Arn ···-" .. •·I ~I ; ~ ~,.., ..... ,. 5.:.. :~: ., .. ~ : ,., ~-l !!t • ' -~ ~ + ... ~ .... ~-(". •t .. ,:_ ...... ..... ...... .,, ... ~~ :,, "'-,'1··\·· • '••l •.,1 ........ , ... :",:·, .. .. ,: .... ,: .. , ... \4111' :0:1 tJ ~ ~ : ~ ? .. -...... -~ .1,.;,.,r , ... .... . .. . . _,,~· ........ , .... ~ •. ~-\f.-1.: ' \,jj '-··•··-<t .. . ., ~ 1 ) . .-...... , ,.J 'Hi ••;-1 :.. .4 .-,,,:;, '"'',··:·. .. :i' -... :'I, ... •.::.i, ., " ,..,,\ ~· •;1 1MIC.,e41i11o1":II" ,•,,: "'· 0 1541ft ~--''",'\ :,t :•.1, '•, ·::,, __ , .• I .. I r King Co unty W.u-r R6so urtr .._ l n¥<nlofy N tH 0 Sm•ts ··~"!IID,,' ,.~ ... ->" ... -:a Parc•I• G111u ndwall'r lhnogcmtnt Artu ukts i nd urgr Riv e rs n.. .-.to,matiOn ~ on f'ila map ha.a be,.,-1 compn.d t,,,, K"lO c.ounty 9lafl l•Cl'fl • vaMty c l 90U-.;M and i. ~ ID changia """"°"' ootioe iang County ~• no rep,..,,\Mlcll'I • or W"lltr•n~. •~• o, Jn'IJii.:Cf. u IO .«'aJ'KY, OOtfl&H ...... •. ltnMne-. Of ri,ghl , IQ !he \IN cl •.ICl'l lrolonnaOon ftii. doc:U'net\l I• hOI ~ -:.11:.-:, ~au,:~ ~n':;111t N>I ho liatN tor eriy gvoer.Z, ~. lnOltea., tnCIOvntal . 0t con NQVel"l1..al di<t~ lrldutt"IQ t,u, nor lo~1 to to« re ..-.nue• M lo« pt011la r~ troff\ th.I uaa 0t m1,~ ol the inloffl'lation oo,,t,1.-...:J on lhla ma.) My u.kl d 1h11 m41P or ,ntormOon on lht• map Ui Oe\41 \2/1 &'2007 Sou~ '°"IV Col,inry 1MAP · 0,,.,..,,C,-e.1$1 Prc;qam fhtlp1~ tNt•ok.c goy.'Ol $/IMAP) U) King County .~ ~ C15 3 1 0? '. r'\ ,J q ~ ~-LOCATION .AND "D1£ECTI O}J r,-./- TAl.ZE~\ OF 17 PHOTO'S j SUPPLIED ·-_l ~ . ~ NO l20AD '"ffil5 SECI1DN1 1 ~ a: \d p ' ~ . . . .. ·-· ~ _ \ ___ ~---·········-----·--··5 EJ3l:l"ffi"5TREEr f----r f C I i ~ I i ~ l------------l OPEN DEA1NAGE j I ..,_ . . d~ 1 ---ri-->-'.___ r,~'-145 r ·------:_·-i 1---®{i)@-®® lJ \[) . ; / : 1,3st~ <;t t L -----1 P5 l l ® l !CA~£. i ----j 1A-® \ ----,---..i ~ ~ 1-:,.,c. 1u '=> r.e,c2.r ......._ ,-------------···· -... .. ·-: 1 ! L~~-x ---~~ ~x .:::::::-"" -L-,.:----1 ; ~J t_: G~LV.l\W.lZED : ~--~5 / ® SCl-100L 'B:s::,. _ I t R,Q~D SAe£::1iE ~-I E X\T ~J f : iJrJE R t s€t5?-i~,JZJ ~::T hl(~S I 0 ~ llBERT Y I-llGH S C\.-100 l.. U: ~ ~· ! 1 -a aof, 'Z d. (·--.... ------····-·-<>•·-··-···-······----------t 2, ( -\,,! ~-, .,...-·,, / ·,. I . r ,:, ,. ' 1 /; / / I \' ' .. \ '' . ..., ~ ~ '• • \, t ~ ' ·- -.. '-fl • .... .., f ;. • "* ! ____ ..... -; --. .... · .. ~ ... t !', 4 _, ~ ~ t· ~ ... , ; ,, J ..• I ! . ~ . . '· . ' ;·;· ··,1· ... .., I ~ I ,'• \ l l, j, .\ \ • I -~. ;, ·" ~ ;: J r '~ . .,. ·/ f ' \ \ ' i .. d . . ,, ~ ~r ~ , ., l • •; \ • t. ~· • ; '; }'. " .. . , j . ,. ; ··.f; • •. 1,, . 'f<-1 . 'T'' !), !J January 3, 2008 Hearing Examiner King County Hearing Examiners Office 400 Yesler Way-Suite 404 Seattle WA 989104 Fax 206 296 1654 RE: Threadgill Preliminary Plat Application L05P0026 Dear Mr. Examiner, We reside at 16445 SE 135 Street within 500 feet of the proposed subject Plat as referenced above. My wife and I have. resided at this address since September of 1983. The Plat creates concerns of; traffic safety, increased flooding potential, unnecessarily increased taxes with no net increase in service value to our property, in fact a decrease in value generally, and potential health issues. T raffle Safety The only access to our property is along SE 136th street to 166 Ave SE and onto SE 135th street. Coming into the property you make a right hand tum around a blind comer. Because the no parking along this dangerous curve is not enforced, we are constantly in danger of meeting oncoming traffic as we attempt to adjust to the obstruction of parked vehicles in no parking spaces. The only fortunate aspect of our situation is that the traffic around this curve is very low, only the immediate neighbors, their visitors, delivery trucks and the postal service use this route. Should the 135th street be extended to pass the subject plat, the increase in traffic from Liberty High School and other vehicles finding, for various reasons, it a more convenient route will dramatically increase the danger of this curve. This is unacceptable for the increased personal danger you are subjecting our neighborhood to absorb. The solution to this problem is to make permanent the dead end character of 135th as it presently exists. There is another problem with extending 135th beyond 164th Ave SE. You would create a jog in the extension of 135th. In addition the jog would occur on a slope ( estimated at 20% grade) which would increase the danger already present by the jog itself. See pictures describing the traffic problems which presently exist. Increased Flooding The site of the proposed Plat is now heavily wooded. Our property is down stream from the plat. Heavy rains to some extent can be absorbed by this woodland. When houses and roadways and sidewalks are created in place of woodlands, the rapid drain off could cause surges of water to increase the flooding danger of our property. We see no adequate provisions in the plat to lessen this danger. The surge ponds described have apparently on! y one outlet each, which tends to focus the runoff. This is not the natural way the present wooded area would drain. Although they may absorb some of the initial surge from the total 4 acre drain problem this is counteracted by all the drain being focused at one point. We would like to see the arguments which support your proposal. The outlet from the eastern pond could overwhelm the existing downstream drainage system and spill over into our drainage problem. See Pictures attached of the flooding presently occurring over part of our property. We have also attached a three year summary of the drainage flow of water over our property. (2005, 2006, 2007) Increased Taxes Our area will undergo a new land assessment due to the new Subdivision created. The increased land value will increase our taxes. This subdivision will not result in an increase in the value of our property, for the reasons given above. Our area will be subject to increased traffic and potential greater flooding damage. The argument that, "well, just sell your property", is not realistic. My wife and I have spent 24 years paying off our mortgage; developing our land, home, shop to suit a retirement life style. "Life Liberty and the pursuit of happiness" as declared in our declaration of Independence has been the essence of our goal and our faith that our government would support this goal. Our governments local, State, and Federal have deviated from this promise and seek only to increase their tax base. We may be forced to sell this property to support what appears to be King Counties unquestionable demand for tax dollars. Health Issues Created by Storage Ponds It has come to our attention by a neighbor who has relatives in Montana, that West Nile Virus has reached that area. It has caused two deaths and illness to others. The disease appears to be moving West. Because of this, I have drained a large outdoor fish pond that we had for several years. An investigation into the chemicals required to add to the pond to eliminate mosquitos were rejected as a solution. They were extremely poisonous and sounded more dangerous then my wife and I were willing to release into the local environment. These storage ponds that we see being used throughout the area in new subdivisions do not seem to drain completely. What is the risk of creating a West Nile virus condition in these ponds, which are located next to and surrounded by new family 2 living areas? What assurance does King County give its citizens that this issue is being properly addressed? Sincerely, Two concerned, long time residents, of King County c;;;: John N and Mai A Case 16445 SE 135 Street Renton, WA 98059 425 271 3167 maja@comcast.net cc Gwendolyn High, President ofC.A.R.E. January 3, 2008 Summary of flow patterns over lower level of property at 16445 SE 135 Street, Renton WA, 98059 January I to February 15 water flowing February 15 to March water not flowing March 1 to March 2 water flowing March 3 to March 25 water not flowing March 4 to April 26 water flowing April 26 to April 29 water not flowing April 30 to May 5 water flowing May 6 to May 17 water not flowing May 18 to May 28 water flowing May 29 to October 31 water not flowing November I to November 18 water flowing November 19 to November 25 water not flowing November 26 to December 11 water flowing December 12 to December 20 water not flowing December 21 to December 31 water flowing. December 27 flow rate rough estimate 1200 gals per minute. Heaviest flow was December 22 no way to estimate flow rate, too wild for my rough estimating techniques. January 1 to March 28 water flowing March 29 to March 31 water not flowing April 1 to April 4 water flowing April 5 to April 8 water not flowing April 9 to April 24 water flowing April 25 to April 29 water not flowing April 30 water flowing May 1 to May 31 water not flowing June 2 to June 7 water flowing June 8 to June 12 water not flowing June 13 to June 16 water flowing June 17 to November 4 water not flowing November 5 to December 31 water flowing January 1 to April 11 water flowing April 12 to April 13 water not flowing April 14 Water flowing April 15 to April 16 water not flowing April 17 water flowing April 18 water not flowing April 19 to April 20 water flowing April 21 to May 4 water not flowing May 5 water flowing May 6 to November 16 water not flowing November 17 to November 24 water flowing November 25 to November 26 water not flowing November 27 to December 31 water flowing ( December 3 took picture of heavy flow included in letter under flooding comments) Compiled by John N Case, resident of property. 42542713167 maja@comcast.net Comment; the goal is to install a proper system to measure accurately the flow across our property. Also a method of sampling the water quality. 2 Threadgill Developement Erik & Michelle Hohlbein 16411 SE 135th Street Renton, Wa 98059 425-226-1615 206-407-7304 Our major concerns with the Treadgill Application: We are directly on the North East comer of the Threadgill property. The proposed retention pond is directly above our property to the west. Looking at plans for the retention pond it seems that the out flow will be running directly across our property and to the south west comers of both our neighbor's property. From accounts of all of our neighbors and previous complaints filed with the county our property used to have a pond on it that was filled to accommodate the house that we occupy. We are extremely concerned with having all the drainage run through our lot and the probability of flooding. We would like to request that the developer find alternative ways to accommodate the drainage from their property. Attached to this letter we have provided drawings and annotated King County Drainage Complaints that better illustrate our concerns. We also would like to request the opportunity to testify and provide more details at the Hearing on this matter, but neither ofus has been able to get pennission from our employers to attend when the Hearing opens on January 8th. We will be available on January 22nd. We apologize for any inconvenience and would very much appreciate any accommodation that might be made. MAIN FILE COPY cus (\J .. JrJ0 e ... .-. \ \ ' I l I I i ~ ,1-----,,--... il : 'JYIJJ.I .te rJrl1 sr •ti "' I 11 '" . '" ~===:t,.~-~-~-~~~~~ "-------=:cr-<::.-=-::::,c..,:::z~ ) I\ ,, I I ,, ,, \\ I \ I \ \I ,, I I I \ \ I\ \\ \\ ·-. -·-·-·-. _, -·-·-· -· -.. -·-·~· .. I I ] I I • ,, 1 \ \, ,t l.:i ~<a .... ~ i fi@ q, I I I :f;_ I 1 : .JI I \ I l , 1 J • I ~ I \ I ' I I I I I ' I I I I ' I I I ~© ] NOV. 17. 2005 4:06PM i KING CO. 1//LRD --,,,: ... : •. c.:·.· CheriLee Kiugt County Public Wodcs Drainage Investiga1ion Sum.: 1100 lll1•3rdAve. Seattle, Wash. 9810 I Maroel C. Gibeault 16115-1191h Ave. SE. Renton, Wash. 980S8 Tel; 228-8411 ~'@@[§OW@@ ii U AUG 1 S ,;g~ -Re;Imptupm: Dminage Dear Ms. Lee KING COUNTY SURfft.CE WATER MANAGEMENT D!V!S!ON It has come to my attenoon that there has been a. culwrt installod actoss SE. l3S1h Str. apprmio,aldy 150 ft. Eastof1he ceme.r of 164th Ave. SE., please refer to yoar:map SW 13-23•5. This cu1wrt does nut show cm the original pw1ij. If tht: County installed 1bis cu1wrt 1D drain the sm:fice w.im:r from 1he NOI1h side of SE. 1351h Str. onto our lot,, thereby usins our lot as a Reten&ion Pond then the; County should have t.o purchase it to do so. Jf 1his oul.vc::rt does not show on your records, we request ;vou remove it immediately and thtlt the property be n:stored to its original condition Your time and cooperauon in this matter would be greatly apprecialed! Thankyou, Marcel C. Gibeault NOV. 17. 2005 · 4:05PM NO. 6127 P. 4 AG!:.M!:.N T DIVl:jlUN DRAINAGE INVESTIGATION REPORT Page~ FlEI.DINVESTIGATION TYPE File Name: File No. Details af Jnve:stigatian; Date Of Field lrwestiga.tlon:..az../ ..LL/ .Q. Related lnvestigalioni;; The area of concern h low in relattonship with the su'('rQuno.1ng preperttes, A re~atively sh<'.11ow swale wtth drairiage from NW to SE is culverte(I under 135th arid outlets into a low v11.cant lot. The x-culVP.rt outlet had rec,,ntly been dug 1Jut from surrounding soi1s and i5 iower than 'the sons. A CB is being constructed in the ditch in front of 16414 and is cor.nerted to the x~culv~rt. There was no flow ~r st.anding water at t~e ti~~- Photo 1) Looks ea!'.t on 136th' with 'Giheau1t Jot on rtght. 2) Shl>ws CB under construcrton in dttoh, 3) Look, northwe.ster~y ~t CZ and concr~te nut1et to CB, 4) Clos~ up nf CB with connection to x-cu1ve~t. 5) X-culvert outlf!t on so11th :side of 135th,. 6) Looks west on 135t.h with CB by mail eo~. Slretch: - '.l . :'i -© ..,_: 5'613C'14i·~ , . ·'.·t --- ' .... .ii.. ... NOV. li. 2005 4:07PM K !MG CO. WLRD COMPLAINT 95-071.5 10BNSON, JEFF Inwstigat.ed by Doug Dobkms on 9-15"-95 NO. 6117 P. 8 Mr. Johnson 1iad been an vru:ation the first part of September and wamed to wait until he got baCk to meet We set tho appolntm,mt'II{) :furthc 15th of September. huctw.tth Jc:ff'and his Uncle o~ to discusll bis cxm=os about dJ:lliDage an 1bis lot he was purchasing, Aa:olllnW to Jeff the County road cmws carm: oat and ci'eened tfie ditcfles and. e,q,osed a c::ro58 aitven tbar had been buried. 'Ille County crews itQppoo at 1he 1'jgbt-of-way ~tbe-wau:r'WOtnl\4 OUllJ:j\, I ~ to Jdf it 'llOt>ll\,l. be up ts> the prop=rty o'lffll« to ~ thi6' warer acmss till: propeey ill the iiamraI dninag,, CllU!ff. Wo Jim, had past · com~ on. thl& pt~ m 1M liallW mason_ All the prm.ons. COD1plaints have been private problems smcenwas the propertyownm; n:sponsiblt'to ~tru:wat.erfrODI. the cm.-s culvert. l explained to Jrfr once this ,;.b;mnel was reop::ued during coJISlrllClion of hill home that it wollld be his reponsibilty to !Il.!lllltain the~~ closed file GIJsill: with Jeff 1obPOOD Call .idf ""'itb. v. \\hone. number for a res14entlal pennft tw,. ··~~ .~ .;;.· ® ... King County Deparnnent of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 R1at',S¢r~enrn,fJ ffir:an§JDitta:' .. ·.···· ... ·· ..... · R~7!i.tm!};clr;¥i~l~t~[!pli~aJion qf,Qa:irif!Jii 1.mJ S:~~fi'il' ,Will:, i:rtl'.6'f;fDl:mif . ·· · . ~clt~,cQfl'i'Nt~t~~tI~'!;(~}gp~~t~;~Lqlf&~\~0,07 ,, ... . . . .· l:1e';jglinei9r($ubrnitta1:~r1ntorrnati~~fllirn:¢tof>irz~ .. 2001 Please provide ten (10) copies of the following, unless otherwise noted. Drainage: • Please resubmit the conceptual 162"d Ave SE offsite drainage/road plan to include an adequate shoulder on the west side. This will likely require tightlining of the existing feature along the west side of 162"d Av SE. Please also revise the drainage plan to show an existing 18-inch cross pipe under SE 144th Stvs. a 15-inch shown on the original plan. The plan should also be revised to show a birdcage type overflow structure, where the east-west drainage swale enters the 162"d Ave SE R/W. • The onsite and offsite drainage plan should reflect Level 3 Flow Control (or other proposed mitigation) as suggested in the Level 3 Offsite Analysis submitted. • Please provide an analysis and estimate of compensating storage required for the existing depression north of the SE 144'h ST cross culvert. • Revise the conceptual drainage plan to include any compensating storage, Level 3 Flow Control or other revisions necessary. • Please revise the conceptual drainage plan to address 3: 1 length to width ratio for the water quality design of the facilities. Note that baffles cannot be used to obtain 3: 1 per Section 6.4.1.2 p6. 6-73 of the KCSWDM. • Please show how the access requirements and grate requirements for the offsite 162"d Ave SE Vault are to be met. If the requirements are not met, a drainage adjustment may be required. • For any questions on the drainage items please contact Senior Engineer, Bruce Whittaker at 206-296- 7211. Revised Preliminary Plat: Provide 25 copies of a revised preliminary plat, as necessary, as a result of above-referenced requests for additional information. Please also include 3 copies of the revised site plan on a reduced 8 W' X 14" page. As a result of the review of the information, additional information (studies, revisions, etc.) may be requested at a later date. Further evaluation of these issues may result in the reconfiguration and/or loss of lots. Cavalla -L06POOO 1 07/07 MA\N f=\LE coPY King County Department of Development and Environmental Services Land Use Services Division Attn: Mr. Chad Tibbits, Project Manager II Current Planning Section 900 Oakesdale Avenue S,W. Renton, WA 9055-1219 RE: Resubrnittal/ Additional Information Plat of Cavalla King County File No. L06POOO I Om Job No. 11778 Dear Mr. Tibbits: CIVIL Ef\lGH~FrRING, U\NJ PLANN:NG. SJRVEYING. Ef,VIROMMENT/\L SLRVICES November 20, 2006 I am enclosing the following documents for your use in reviewing and processing the preliminary plat of Cavalla. I. Ten ( 10) copies of the Traffic Impact Analysis dated October 31, 2006, prepared by DN Traffic Consultants 2. Ten (10) copies of he 162nd Avenue S.E. extension plan prepared by Barghausen Consulting Engineers, Inc. 3. Twenty-five (25) copies of the revised preliminary plat map, road, drainage, adjacent property owners map, and tree retention plans. The following is a response to the May 11, 2006, Plat Screening Transmittal letter. A brief response to each issue (in order) from the Plat Screening Transmittal is provided below: Drainage: • Please revise the conceptual drainage plan to show detail of how the proposed drainage facility will outfall to the south. The plan submitted appears to show dispersal acroYS the proposed sidewalk, which is not an acceptable discharge design. Response: The discharge of the storm pond (Tract A) on Sheet C2 indicates the connection of the storm drain outlet to a proposed storm system in 162nd Avenue S.E. The improvements to 162nd Avenue S.E. are to be extended as part of the proposed plat of Liberty Gardens (King County File No. L04P0034). If the plat of Liberty Gardens is not developed, the discharge would be designed as a sheetflow separator to the extension o'16'"dA ~"~ s E rm~ © fll I \vi ~@ MAIN FILE COPY 18215 72ND AVENUE SOUTH BRANCH OFFICES + OLYMPIA. WA NOV 2 2 2006 King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -2-November 20, 2006 • Please show how the 3:1 length to width water quality ratio is to be achieved in the drainage facility. Response: The storm drainage and water quality pond is revised to provide a baffling system to meet the 3: I length to width ratio. Traffic/Roads: • The Subdivision Technical Committee has noted in our review to date that an evaluation of the impacts of the three pending plats: Cava/la (L06POOOI), Liberty Gardens ( L04P0034) and Threadgill ( L05P0026) will have an impact on a listed High Accident Location at the intersecrion of Southeast 128th Street/162nd Avenue Southeast. Response: Please attached Traffic Impact Analysis (TIA) prepared by DN Traffic Consultants for the plats of Threadgill/Cavalla/Liberty Gardens dated October 31, 2006. • The STC wishes to advise you that potential mitigation that appears to be feasible and capable of being accomplished is available to address the cumulative and significant impacts of your proposed development and the other two pending plats cited ( Liberty Gardens and Threadgill). This mitigation would include an extension of the frontage improvements for the plat of Threadgill easterly from 164'' Avenue SE to the intersection of 166'h A venue SE. Response: In a combined effort with the developments of Threadgill/Ca valla/Liberty Gardens, Barghausen Consulting Engineers, Inc., surveyed the unimproved right-of-way of the potential extension of S.E. 136th Street east from the plat of Threadgill to the existing road improvements near Liberty High School. Additionally, as an option of the three developments, we also surveyed the unimproved right-of-way of 162nd Avenue S.E. from the southwest comer of Liberty Gardens to S.E. 144th Street. Barghausen Consulting Engineers, Inc., then requested that Chad Armour, LLC, locate any environmentally sensitive areas within the right-of-way of both options. With this information, Barghausen Consulting Engineers, Inc., prepared preliminary road designs and profiles to determine the potential for a road extension for a secondary access for all three projects. We then met with King County to discuss these options. Based on the fact of topography, grades, and sensitive areas and for the fact that existing right-of-way does not exist for the complete roadway section, it was detennined that the preferred option for this project is the extension of 162nd Avenue S.E. to S.E. 144th Street. The 162nd Avenue S.E. extension also has sensitive areas; however, based on our design, we believe they can be mitigated. Furthermore, we believe that this access provides a better alternative secondary access for this area. King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -3-November 20, 2006 • This would also appear to address issues of school walkway safety (RCW 58.17) to Uherty High School and Briarwood Elementary. This connection provides access to a currently-signalized intersection of SE 128//' Street/169'" Avenue SE. Response: As required by King County ODES, we have designed the plat to provide on-site sidewalks as well as access through the proposed park (Tract B) and through a 10-foot pathway serving Liberty High School. It is our understanding that the same requirement is required at the plat of Cavalla. This access will provide safe access for the high school students being served by Liberty High School. We will need to meet with the School District and determine if openings to the existing fencing surrounding the high school would be appropriate. • This potential environmental mitigation will he further evaluated during the traffic review of each the other two plats currently being reviewed, as well as this project. A similar request is being made of the Applicants for the Cava/la plat and the Liberty Gardens plat. Response: Comment noted. A TIA for all three projects (Threadgill/Cavalla/Liberty Gardens) has been prepared and is enclosed with this resubmittal. • In order to review the proposed project, please provide a conceptual frontage improvement plan for SE 136th Street (plan and profile) --extending easterly between 164th Avenue SE and 168th Avenue Southeast. 11,is extension should be designed to the standards for a Neighborhood Collector, and the plan view should include any required retaining wailslrockeries!slope grading in addition to the roadway improvements consisting of a curb, gutter and sidewalk section, a minimum of 22 feet of paving, and associated stormwater facilities (culverts) and detention/treatment. A full 60-foot wide right-of-way extends through this segment, except for parcel located on the ( if extended) southeast corner of the 164th Avenue SE/Southeast 136th Street intersection. There appears, here, to be a 30-foot wide right-of-way on the north side of Southeast 136th Street and a roadway easement (also 30-feet in width) on the south side of the 'centerline' of this roadway. Response: As discussed above, we have analyzed both sections and provided conceptual profiles to King County. Also, Mr. Curtis Schuster met with the prope11y owner of Tax Lot 1323059039 (Lovegren) to discuss the potential of obtaining additional right-of-way for the extension of S.E. 136th Street. Mr. Lovegren indicated that he really did not want additional traffic across his property and that any further proposals he would need to discuss with this attorney. Based on this information as well as further research in this area, we determined that the preferred option is the extension 162nd Avenue S.E. to S.E. 144th Street from the southwest comer of Liberty Gardens. Therefore, we have enclosed ten (10) copies of the proposed alignment, road improvements, and profiles. King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -4-November 20, 2006 • In order to determine the precise roadway section required, and walkway improvements needed, please provide a Level 2 TIA. This TIA should include an assessment of the cumulative impacts of the three pending development applications (Threadgill, Cava/la, and Liberty Gardens), the volume of impacts at the HAL at Southeast 128th/160thAvenue SE, and any additional non-project traffic ( Liberty High School and existing developed lots in the vicinity) that would reasonably be expected to travel on this section of Southeast 136th Street. Include impacts and levels-of-service (AM and PM peak hour, during the school year) at (at least) the following intersections: I 56th Avenue SE/Southeast 136th Street, 169th Avenue Southeast! Southeast 128th Street Southeast 136th Street/160th Avenue Southeast Southeast 128th Street/I 56th Avenue Southeast Southeast 128th Street/160th Avenue Southeast Response: We have enclosed ten (10) copies of the Level 2 TIA prepared for the plats of Threadgill/Cavalla/Liberty Gardens that addresses all of the intersections referenced above and the high accident locations. • In addition, the proposed project may have a measurable ( I or more peak hour trips) at a High Accident Location (intersection) at the intersection of State Route 900/ I 64th A venue Southeast. Please include, in the TIA, an assessment of the project's impacts (number of peak hour trip-ends, only) at this location. Based upon the impacts of the development at that location, a requirement may be imposed to financial contribute (reimbursement) towards reduction of the impacts of the HAL (signalization at the intersection of 148th/ SR 900) via signalization being jointly funded by other developments in the area. Response: As indicated in the Level 2 TIA, all three plats will be required to pay an MPS mitigation fee and a pro rata share of the cost of the improvements at the 148th Avenue S.E. and SR-900 intersection. Additional road comments: l. KCRS Section 2.09.4 requires that the roadway to which an alley (Tract "C") connects shall be a minimum of 28 feet in width (i.e. the Subcollector standard), with vertical curbs. Please revise Road "A" to comply with this requirement. Please revise the design of the frontage improvements to 162"d Avenue SE to comply with this requirement. Response: As required by King County, we have made the appropriate revisions and provided the minimum of 28 feet of road width. 2. Please provide a conceptual plan for an alternative design for the south half of the proposed project (the parcel upon which was proposed the preliminary plat of King County Depai1ment of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -5-November 20, 2006 Dickenson) that provides a public street connection between this plat and the proposed plat of Liberty Gardens, and terminates Road B with a temporary turnaround. Response: This comment is no longer applicable since we are proposing the extension of 162nd Avenue S.E. to the intersection of S.E. 144th Street. Therefore, a turnaround is no longer applicable. 3. Alley/ Tract "C" Alleys should have a straight cross-fall, or, normal crown section. Please revise, and adjust the conceptual drainage plan as necessary. Please revise the design near the NE corner of proposed Lot 34 to accommodate the low-speed curve requirement from K CRS 2.10. Please provide verification that 150 feet of stopping sight distance will be available through the entire length of the alley -in particular at/near the curve abutting the NE corner of Lot 34. Response: We have added a 150-foot stopping sight distance triangle to the plan to show this requirement can be met. 4. Please provide a Traffic Impact Analysis to address the impacts of the proposed development at the following intersections: • • • SE 128'' Street/16/J' Avenue SE SE 1213'' Street/1561 ' Avenue SE SE 1361 ' Street/1561 ' Avenue SE Response: These intersections have been addressed m the Level 2 TIA prepared by DN Traffic Consultants dated October 31, 2006. S. Please revise the site plan to show a temporary turnaround at/near the southerly end of 162"d Avenue SE. Response: A temporary turnaround is no longer needed for this project because the plat will be required (along with the plats of Threadgill and Liberty Gardens) to extend 162nd Avenue S.E. to S.E. 144th Street. Critical Areas: • Please demonstrate that buffers being used to protect off-site wetlands are correctly using the current King County Critical Areas standards located in KCC 21 A.24. To King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Ctment Planning Section -6-November 20, 2006 Contact Nick Gillen, Senior Ecologist with questions regarding this requirement at (206) 296-7141. Response: As part of the extension of 162nd Avenue S.E. for the plat of Liberty Gardens, the impact to a wetland and buffer will be mitigated and, therefore, will have no impact to the southwest corner of this project. As part of 162nd Avenue S.E. improvements, a mitigation plan will be prepared for that project. Recreation Space: Submit a conceptual recreation plan that indicates the type of improvements (i.e. sport court, play structure, benches, landscaping, etc.) proposed within the recreation tract(s). See KCC 21A.14.180(E)(2)for equipment requirements. Response: Please find enclosed the preliminary plat landscape park plan as required by King County. The park provides two play structures and meets the required park area. See Sheet PL 1 of 2. Conceptual Significant Tree Retention Plan (Mitigation); Submit a conceptual significant tree retention plan and/or a mitigation plan for the plat. Response: Please fiml enclosed the significant tree retention plan based on King County requirements. As required by code, we must provide 89 replacement trees. We are proposing to save five trees on site. Walkways: Provide an inventory map (i.e. existing conditions -widths, surface type, etc.) of the walking routes to the elementary, middle school/junior high, and high schools and/or the appropriate bus stop location associated with each school. Identify any improvements necessary to provide safe walking conditions. Response: An inventory map is not required because all grades (elementary and junior high school) are bused. However, high school students (Liberty High School) will get access to the school (which abuts the plat's east boundary line) via a IO-foot pathway (Tract C). Proof of Legal Lot: No proof was submitted that this is a legally segregated lot. The underlying 1907 plat did not create legal lots. A deed for the parcel in the present configuration dated prior to October 1, 1972 or tax records prior to 1972 with the parcel in the current configuration were not submitted. Response: On May 26, 2006, we provided this information to you from our title company. However, we have also enclosed additional copies for your review and approval. > ,I King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -7-November 20, 2006 Revised Preliminary Plat: Provide 25 copies of a revised preliminary plat, as necessary, as a result of above-referenced requests for additional iriformation. Response: As required by King County, we are providing 25 copies of the preliminary plat of Cavalla, preliminary road and profiles, and drainage plan, adjacent property owners map, tree survey map, off-site extension plan for 162nd Avenue S.E., preliminary park plan, and significant tree retention plan. I am confident that the enclosed information provided adequately addresses the Plat Screening Transmittal letter dated May 11, 2006. If you need additional information, please contact me. Respectfully, ~ cx!/aJ~)rL~ife,- GWP/tep 11778c.006.doc enc: As Noted cc: Mr. Bob Ruddell, KBS JII, LLC Mr. Kolin Taylor, KBS III, LLC G. Wayne Potter Project Manager Mr. Curtis Schuster, KBS Development Corp. (w/enc) Mr. Daniel K. Balmelli, Barghausen Consulting Engineers, Inc. Mr. Ali Sadr, Barghausen Consulting Engineers, Inc. • Legend -1 I_ County S.Oundary Streets Parcels Contours (5ft light! IIIIJh'"")' D Parks 100; 500: 1000 Artarials Shaded Relief ()tJ,,r,r l.oGal Highways D Lakes and Large Rivers ;../ Incorporated Area Streams The information included on this map has beon compiled by King County staff trom a variety of SO!.lrces. and is subject to.change .without notice. King County makes no rep_resentat1ons or warranUes, express or implied, as lo accuracy, completeness, timeliness, or rights to the _use of such iniormation. Th,s document is not intended for use as a survey product. Kin9 County shall not be liable lor any general, special, indirect, incidental. orconsequenttal ~-K"1ng County damages including, but not hmiled 10, lost revenues or lost profits resulting from lhe use or misuse or the 1nforma1lon contained on this map. Any sale of this map or 1nformato11 on this map is prohitnted except by written permission of K1:ig County. Date: 12/31/2007 Source: King County iMAP-Property Information (http://www.metrokc go11/GIS/JMAP) f ' FW: Inquiry: Accident reports request and a signage question F:·om · Scanlon, Jodi (Jodi.Scanlon@kingcounty.gov) \lvou may not know this sender.Mark as safe I Mark as unsafe Senc Wed 1/02/08 2:55 PM To: highlands_neighbors@hotmail.com Gwendolyn, Please don't forget the following adjoinder that I am required to include. (And I am attaching a few minutes late for your enjoyment.) Thanks, Jodi Be advised that accident statistics and reports compiled or collected for highway safety purposes are not subject to discovery, are not admissible in any action for damages, and may not be the basis for opinion testimony in any such cases. See 23 U.S.C. section 409; Pierce County v. Guillen, 123 S. Ct. 720 (2003). From: Scanlon, Jodi Sent: Wednesday, January 02, 2008 2:49 PM To: 'Highlands Neighbors' . Subject: RE: Inquiry: Accident reports request and a signage question Gwendolyn, Here is your collision information. The information that I am providing is 1/1/2002 -12/31/2005 for each location. If the distance is O that means that the collision took place at the intersection (or relating to the intersection). OD means opposite direction, SD means same direction. The rest should hopefully be pretty clear. Please let me know if you have any questions. Thanks, Jodi (206)263-6111 SE 128th St@ 156th Ave SE D:\Tlo'. TIME DISTAN WE1\TI-!lm COLLIStOr,.; TYPE STREE'l' 1 STJU.".E'l' 2 01/10/2002 11:ll3 0 Ovcrca~t Right angk 1S6Tl l AVE SE SE 128Tll ST 01/22/2002 18:15 0 O\'crcast SD both sLraigh 15(JrJ--f :\VE SE SE 128'1'1 I S'J' 0.7,/22/2J.l02 1 IJ:10 (J Clcar/1\1.rtly Cl OD onl' It turn 15(>°r! l AVI•'. Sfi. ~m 128"11-T ST 12/2.',/200119:00 0 Clear/Partly Cl H.1ght an,Q,k 15(1TH ;\VI•: SE SF 128Tl-l ST 03/21/200.113:020 Raining Right angle 156'11I AVESJ'I'. SJ'.128TT[ST 08/H>/2003 20:30 0 Ckar/Partlv Cl Vch s1rikc:; fix 156111 AVE SE SE 12!:ITll S'f 08/24/2003 15:48 0 Clcar/l'artl;, Cl Righi angk: 156TI-J AVJ•: Sr·: SI•'. 1281'! I ST 04/08/200417:28 0 Clca~/Partly Cl Rigbt angle 156111 AVE SE SE 128Tlf ST 0/s/ l 1 /2004 17:25 O Clc1tr/l'a.rtly Cl :,;l) both ~tr:ugh 156'!'1 l ,\VE SJ! SI·'. 128TJ I ST 01/04/2005 lJ:45 0 Clcar/J'anl_1· Cl Right angle 156'1'1 I AVF SF Sl·'. 128Tll ST 04/25/200.i 7:00 0 Clear/Pardy Cl SI) both strngh 156TH ,\ VJ•: SE SL'. 128TH ST 06/21/2005 17:20 0 Rammg SD buth ~trai!-!h L56Tf l ..-\ VE SE SI'. 128TH ST 09/29/2005 18:00 0 lturung Sl) brlth ~traigh 15(1TrI AVE SE SI•: 12/:rI'J I ST SE 128th St@ 160th Ave SE D.\Tl·: Tll\iE DJSTAN WEATllEJ{. COLLISION TYPE STREET 1 STllEI..;'J' 2 01/02/2002 18:57 I) Ovvrcasr SD hrnh ~traigh 160TI I ,\ VE ,q,: Sl•'. 128'1'! 1 ST 02./22/2(!1!2 l(i:20 (l (>verc;l~t Sl) b,,th straigh 16ffl.l ! AVI.\ st,: SI~ 128"1'! l S'J il.1,/15/200212:000 Ovcrca.~t UDoncltturn \60Tfli\VESF SE128THST 04/20/2002 15:30 U Clcar/l'artly Cl SD bntb straigh 16UTI1 :\VE :::,E s1,: 128TIJ :c-;T 09/15/2UU2 13:20 0 Clc:ir/1'.i.rlly Cl OD one it turn 1(,0'J'H :\\!ESE sr,: 1'28TH ST U2/V4/2(HJ3 7:45 ll Clear/Partly Cl Right angle !6{n1 J t\ VE SE SE 128TII ST (l8/B/2rnl3 20:20 (J Ckar/l'artly CJ SU one 11 Mn l(iOTH .\VE SI'. SE 128TJ l ST (J(,/22/2004 19:5111 Cltar/l'artlv Cl OD um: It turn 160'Il-J i\VF SE SJ,: 128TH ST JO/ 12/21Hl4 16:58 0 Clear/l'ar1l;, Cl 01) um: It turn 1(,(fl'}I A VJ•: S!' SJ_•: 128'l'f 1 S'l' 11/115/2011·11 i:30 0 Cbr/Partf}, CL SD both strrugh !60'\'I l ,.\ VI•: SE SI<'. 128'I1-T ST 11/08/2004 19:27 0 Fog/Smog/:.-,;moke 01) one lt tum 1(1UTI I ,\ VI•: SE SE 128TI I ST Ol/05/2005 9:14 (I Clear/Partly Cl Sl) both wa.igh 160TI! AVF SE sg 128TH S'l" 05/27 /2()05 15:40 0 (;]ear/Partly Cl SJJ lmth ~traigb 160111 AVE SE ::::F 1w·n l 51' 07/21/2005 11:18 0 Ckiar/l'artly Cl Right ani.,,Jo.: 160TH AV l~ SL! SE 128'1'! J ST l0/19/200519:11 O <l,·erca.,t ~Dborhstra.1gh J(,()'}'JIJ\VJ,:SLc SE J28'11IS'I' SE 136th St@ 156th Ave SE MAIN FILE COPY ,. No collisions. SE 136th St@ 158th Ave SE No collisions. SE 136th St @ 160th Ave SE No collisions. SE 144th St @ 16oth Ave SE DATE TL.ME !)]ST1\N Wl!ATI !ER [OJ .LJSJCJN TYPE STlU\ET 1 STREET 2 !J4/19/200423:301l ()vcrca~t Vch~trikc~fix160111:\VESE :-;1•:144T!TST From: smith5124@aim.com Sent: Sun 12/16/07 7:04 PM To: highlands_neighbors@hotmail.com I don't know about 156th, but I was hit at the in:::ersection of 136th and 158th. We were heading west towards 156th when a gal come from our left and hit us. That was Jan. 3rd before the stop signs were put up on 136th. We almost got hit there again last week when someone blew through the stop sign. Be very careful there! March 18, 2007 John & Nenita Ching, 16038 SE 142nd Place Donald & Andrea Gragg, 160i'tSE 142"d Place Norm & Patricia Gammell, 16043 SE 142nd Place Renton, WA 98059 Ed McCarthy, Ph.D PE Haozous Engineering P.S. 9957 171" Avenue SE Renton, WA 98059 VIA: CERTIFIED MAIL Dear Dr. McCarthy: It has been nearly a year since we brought to King County our concerns about excess surface water running into our properties. There has been an unprecedented volume of water passing through our properties because of development north of our homes. The volume of water passing through our properties has been constant and is causing deterioration to our land. This letter serves to inform you that, because King County has not fixed the problem of excessive surface water flowing through and into our properties and the adjacent undeveloped King County right-of-way, and in order to protect our homes, we will be installing drainage pipes, and contemplating other options as well. Yours truly, Owners of property located at 16038 SE 142nd Place: Owners of property located at 160311 SE 142nd Place: 't-(. ~~g~ Owners of property located at 16043 SE 142nd Place: ~~y.// No G ell MAIN flLE COPY '° n, D Ul Ir Ul n.J D ~ D D D D r'i '° D .Jl I U.S. Postal Servicer.. CERTIFIED MAIL.. RECEIPT (Domestic Mail Only; Na Insurance Coverage Provided) . . " ,_, "°""' pl.• A .~ 1 ;\ 'I ; ' '53 7"' SEAIJLE'IJ/l 1981Q4 l, u ,_ '.h.m .',b . Postage $ $0.39 , 0267 "--- Certified Fee $2.40 14 .- Postmark Return Receipt Fee $0.00 / , Here {Endorsement Required) ~ :;-.. Restricted Dellvery. Fee $0.00 (Endorsemeni Required) . · .. Total Postage & Fees $ $2.79 . 03/21/2007 ~ SentToC)htfwf/ i!JLl't/Yllt{ -/,l}t1Uy$/w,d_ f},5{)lYft::, ["'-Srroet, Api No.; V -/. ~ .,. .J-. o,POBoxNo. ;)OJ 6 1)4.CKoY/ U/ . Ul ~ D Ul Ir Ul n.J D ~ D D D D r'i '° D I Clty,S/ate,ZJ/>+4 c7tAtt/J., wt! 1ff JD"/-o:S...55 PS Form 3800, June 2002' See Reverse for Instructions U.S. Postal Service™ CERTIFIED MAIL" RECEIPT (Domestic Mail Only; No Insurance Coverage Provided) . .,. '· •iii~S? C !A L l! ~ -..., rE Postage $ $0.39 ' 0267 . Certified Fee $2.40 -Iii Return Aecelpt Fee Postmark (Endorsement Required) $0,00 , ./~;, . ~e~ Restricted Delivery Fee (Endorsemenl Required) $0.00. . •. ' Total Postage & Fees $ $2.79':;; 03121/2007 __ .-- ~ •so.,;;;nt""'o,---C,-,-------#,-----,------------ !C;' .....•.............. t1. .... ff c (,,JY, .k'1 --/f,r1JCl:b110 .G,JJ_;'nRPV?;J , -Stroet, Apt. No.; 6 . 7,/ of Q -······tJ- o, PO Box No. 1-;57 I G City, State, ZIP+4 /fri/1n µ),/ 'f O O 61 PS Form 3800, June 2002 See Reverse for Instructions I I DEVELOPER'S LIMITED USE PERMISSION FOR TEMPORARY CONSTRUCTION ACCESS THIS LIMITED USE PERMISSION is made this /lf"[JJ day of 02~ , 2004, by and between Donald B. and Andrea Gragg ("Property Owner''), and S Development Corporation ("Developer''), and/or assigns. Donald B. and Andrea Gragg are the legal owners of that certain real property known as Tax Parcel Nos. 725370-0110 and 725370-0120 known as Lot 11 and Lot 12 of Rich Lea Crest located at 16046 S.E. 142nd Place and 16042 S.E. 142nd Place, respectively ("Property"). KBS Development Corporation is the developer of a plat known as Hamilton Place (King County Project No. L02P0011), located between 158th Avenue S.E. and 160th Avenue S.E. As part of the development of Hamilton Place, King County is requiring repair and improvement to existing drainage facilities as shown on the attached Exhibit A based on the approved Sheet C13 of 13, Downstream Drainage Improvement Plan. Property Owner hereby grants permission to Developer and/or assigns to enter onto the real property described above under the following conditions: )__..,..-------- 1. Term: Unless otherwise terminated ~~n' 'lf(e\terms hereof, the term of this permission is from June 1, 2004 until Oe~e* 1, 2004. This temporary permission shall utomatically terminate upon completion of all improvements for the plat of Hamilton Place (King County Project No. L02P0011 ), in the event such completion occurs prior to c Oe~ehc: I, 2004. '"t>eif/1/:el 2. Developer's Use of Property: Developer's use of the Property shall be for access to implement construction of improvements for the plat of Hamilton Place. 3. Restoration: Upon termination of this permission, Developer will restore the surface of the Property to a condition as good as or equivalent to its condition prior to entry by Developer, except that Developer shall not be required to replace trees removed within the Property. Developer will exercise its best efforts not to damage any private improvements on the Property, but if it does so, it shall repair and/or replace said improvements. EXECUTED as of the date first above written. Andrea Gragg, Properfyner Gragg Construction Permission Ltr STATE OF WASHINGTON COUNTY OF /t1J'v:J ) ) 55. ) On this // [ti day of t?J ~ , 2004, before me personally appeared Donald B. and Andrea Gragg, to e known to be the individuals described in and who executed the within and foregoing instrument, and acknowledged said instrument to be the free and voluntary act and deed of such parties for the uses and purposes therein mentioned. Signature of Notary Public Dated Residing at KJ:t!Kt 4JvtJ Appointment Expires: f -.3 0 -Os Gragg Construction Permission Ur I PROPOSED I 1/2,1 (TYP.) OF so' W!OE UNOPSNEO R w FOR 162ND AVE 5.E. (APPROX. LOCATION ONLY) REGRADE EX. DITCH TO TO ACHIEVE A 1 1 /2: 1 -_-_ -,,g-,~=-=--~~--~~--~~---~~---~- -.i._-,:;/=-wr MAX. SlDE SLOPE. .,~---,-----1- ----'.;1.,~,-.:A::,-,-/--:.::...-.::..;:: ~~;.= = = = =: =::Y = = = = / CONCRET£ / ARMOR DITCH WITH s· TD s· QUARRY I SPAl.l.S WITH A l THICKNESS OF 12• I / / / CULVERT O 2.33% PROPOSED TOE OF SLOPE / // // -- / / / -·~LOT LINE (APPROX. LOCATION ONLY) NOTE, CONTRACTOR AND/OR OEVEl.OPER SHALL COORDINATE WITH PROPERTY OWNERS OF LOTS 1 1 ANO 12 PRIOR TO BEGINNING CHANNEL IMPROVEMENTS. ~~9.0 ---------~~,-~~--,.~~~~--, NOTE, SEEKEf MAP FOR LOCATION '· /EX· TOE OF SLOPE /EX. TOP OF SLOPE 40: . '•Oat EX. CHANNEL IMPROVEMENT PLAN olDDmONAL INFORMATION DOWNSTREAM IMPROVEMENTS, ® >"L'\'t.l'fll'~'T\ Bruce Whittaker Senior Engineer \ Land U e Services Division· -----------· - Dep t ofDevelopment and Environmental Service:,; 900 Oak ale Avenue Southwest Renton, A 98055-1219 (206) 296-7211 FAX 296-6613 T1Y 296-7217 E-mail: bruce.whittaker@metrokc.gov DEVELOPER'S LIMITED USE PERMISSION FOR TEMPORARY CONSTRUCTION ACCESS ,[}! ;J. THIS LIMITED USE PERMISSION is made this /7 day of (); ~ , 2004, by and between Donald B. and Andrea Gragg ("Property Owner"), and S Development Corporation ("Developer"), and/or assigns. Donald B. and Andrea Gragg are the legal owners of that certain real property known as Tax Parcel Nos. 725370-011 O and 725370-0120 known as Lot 11 and Lot 12 of Rich Lea Crest located at 16046 S.E. 142nd Place and 16042 S.E. 142nd Place, respectively ("Property"). KBS Development Corporation is the developer of a plat known as Hamilton Place (King County Project No. L02P0011), located between 158th Avenue S.E. and 160th Avenue S.E. As part of the development cf Hami!tcn Place, Klng County ls requiring repair and improvement to existing drainage facilities as shown on the attached Exhibit A based on the approved Sheet C13 of 13, Downstream Drainage Improvement Plan. Property Owner hereby grants permission to Developer and/or assigns to enter onto the real property described above under the following conditions: 1. Term: Unless otherwise terminated pursuant to the terms hereof, the term of this permission is from June 1, 2004 until October 1, 2004. This temporary permission shall automatically terminate upon completion of all improvements for the plat of Hamilton Place (King County Project No. L02P0011 ), in the event such completion occurs prior to October 1, 2004. 2. Developer's Use of Property: Developer's use of the Property shall be for access to implement construction of improvements for the plat of Hamilton Place. 3. Restoration: Upon termination of this permission, Developer will restore the surface of the Property to a condition as good as or equivalent to its condition prior to entry by Developer, except that Developer shall not be required to replace trees removed within the Property. Developer will exercise its best efforts not to damage any private improvements on the Property, but if it does so, it shall repair and/or replace said improvements. EXECUTED as of the date first above written. Andrea Gragg, Properfy7ner Gragg Construction Permission Ur • Threadgill Plat Concerns Date: IJ, /), g I o7 -~~, ~r.-'-- Name / ~ ;u:, ~ L/fi2,C, -Z Address::::;:;:'f::;:,__,1::"il't:t£ ... ::1:2>:s:tt::1:S:'t:.:,:e::w1ro::::::1a:1:d:::2:1i:o:s:::2::: Phone f 'J..!:'-t1/-fJ 7 30 ; 1 My property is _. __ ._ .... ~i..!..:,..::..::.::=a::a:.i.-..i.:.:.:i...:a::a:::...!..=~---~~=.c....~J..J.1~'""""'~~"'""'~""-!.', LL of <..w:.....i:.~w.:~~~~~~~.....!al~.:"4:;iJ;ll:-f<l~~--'::l~~µ;....r,a;.'JIU.~~u:z.'r.L.1~ ~ne~ ~;:.,4~~~~.:i_.1:!,LJ.1.'qz!.:.¢.....QJt._,aJ,£:[_L,..a!:....(.~...../L!#.,~~!l::Z.;..C:!::£i;;g,~;i4-,.~~nuw ~~~~~~~~~~~iLL~~~!/:£,LlLL.3..:w'.:6...,:1.St wr nwsf ~~~.:J......~~µ!:U.&.~;.:rJJ:e,;_~~~t.i4J.l...a.a.--1.,:Jµ::2.µ.ZW.J+~~1::.o I H fh ft.it. tfe? c;tr#:. 1~AIN FILE COPY L,:JS f\_)l)~lp ----~----· • • '. ~·~··· i .' • JI, •.• ''!. ,-p.~,r . ~ .. • .. ..-, . .,! • . , . ..4 I ,-.:· ··~ {' tJ\ . i.,.,, .j- -. . ~__...,--.-,.....-:·,..J ,' ,e-.. .,- .,.,~-~ ! ... ·-·~ CASCADE WATER ALLIANCE Final Environmental Impact Statement Tacoma-Cascade Pipeline Cascade Water Alliance Cascade Regional Water Supply System April 26, 2007 k Ci\SCADF . ,·t>: '··"''•" Fact Sheet Project Title Cascade Water Alliance, Cascade Regional Water Supply System, Tacoma-Cascade Pipeline Description of the Proponent The proponent of the Tacoma-Cascade Pipeline Project is Cascade Water Alliance (Cascade}. Cascade was formed by a group of cities and special districts that own and operate public water systems in King County to jointly plan, develop, and operate a water supply system for its members. Each of these water systems is authorized to provide water within its designated service area. The members of Cascade have entered into an lnterlocal Agreement to enhance their ability to supply water to their respective service areas and the region by developing, owning, and operating regional water supply assets. The members of Cascade are: • City of Bellevue • City of Tukwila • City of Issaquah • Covington Water District • City of Kirkland • Skyway Water and Sewer District • City of Redmond • Sammamish Plateau Water and Sewer District Description of the Proposed Action The Proposed Action involves constructing and operating a buried water supply pipeline, the Tacoma-Cascade Pipeline (TCP) and ancillary features, to connect the existing Tacoma Water Second Supply Pipeline (SSP) to the existing Bellevue-Issaquah Pipeline (BIP). The pipeline would be approximately 20 miles long and 42 inches in diameter and would bring water purchased from Tacoma Water to Cascade's members. Two action alternatives for the pipeline route (the Preferred Alternative and the Green Route Alternative) are being considered in addition to the No-Action Alternative. The action alternatives are located in King County within the following jurisdictions: • City of Bellevue • City of Newcastle • City of Covington • City of Renton • City of Issaquah • Unincorporated King County • City of Kent The majority of the pipeline would be constructed within public road rights-of-way. However, the pipeline would also cross private property and undeveloped lands. FINAL EIS: Tacoma-Cascade Plpeline Fact Sheet FS-1 -k USC AD F 'C,, I<" \Cl' I~• • Description of the Alternatives This Environmental Impact Statement {EIS) examines the following three atternatives: 1. No-Action Alternative. Under the No-Action Alternative, Cascade would not construct a new water transmission pipeline. Water would continue to be supplied through members' independent supplies, through wholesale water purchased by members from non-member water purveyors, and through a declining block contract with Seattle Public Utilities (SPU). Forecasted demands would not be met. Increased demand as a result of population growth, in combination with the declining SPU contract, would result in inadequate water supplies for Cascade members. 2. Preferred Alternative. The Preferred Alternative (see Figures 2-2 and 2-3) would be approximately 19.1 miles long. It would begin at the SSP, generally follow 160th Avenue SE or 164th Avenue SE north, and cross SR 18. There is also an option for the Preferred Alternative to continue on 164th Place SE, turn northwest on Covington Way SE, cross SR 18, and turn west on SE 272nd Street to 156th Place SE. It would then follow 156th Place SE, 156th Avenue SE, SE 224th Street, 148th.Avenue SE, SE 192nd Street, and 14oth Avenue SE to the SR 169 crossing. There is also an option in this area that would run cross- country on private property from near the intersection of 14oth Way SE and SE 156th Street north to the SR 169 crossing. The Preferred Alternative would continue east on the paved Cedar River Trail. North of SR 169, the pipeline would travel north along 149th Avenue SE, Jones Road, and along 154th Place SE, then cross-ccuntry through a King County-owned parcel, along 156th Avenue SE, SE 144th Street, and 160th Avenue SE to SE 128th Street. The pipeline would then run east on SE 128th Street and then north on 176th Avenue SE to SR 900 in the May Valley area. From the May Valley area, the pipeline route would follow SR 900 northeast to the BIP. In south Issaquah, there are options along SR 900 to run cross-ccuntry, roughly parallel to a Puget Sound Energy (PSE) right-of-way. The jurisdictions along the Preferred Alternative include the cities of Covington, Renton, and Issaquah, and uninccrporated King County. 3. Green Route Alternative. The Green Route Alternative (see Figures 2-2 and 2-3) would be approximately 21.9 miles long. It would begin at the SSP and continue north on 132nd Avenue SE. It would then turn east on SE 208th Street and north on 14oth Avenue SE. The Green Route Alternative would follow the same route as the Preferred Alternative between SE 192nd Street and 156th Avenue SE. It would continue north on 156th Avenue SE, generally following SE 128th Street, 148th Avenue SE, SE May Valley Road, Coal Creek Parkway, and SE Newport Way to the BIP. The jurisdictions along the Green Route Alternative include the cities of Kent, Renton, Newcastle, and Bellevue, and unincorporated King County. Proposed/Tentative Implementation Date A decision will not be made about the Proposed Action until at least 7 days after issuance of the Final EIS. However, a proposed date for implementation would be the latter half of 2007. SEPA Lead Agency Cascade Water Alliance is the lead agency for this proposal. FS-2 FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet SEPA Responsible Official/Project Information Contact Person Michael A. Gagliardo, General Manager Cascade Water Alliance 11400 SE 8th Street, Suite 440 Bellevue, WA 98004 (425) 453-0930 Permits and Approvals that May Be Required for an Action Alternative Agency/Jurisdiction Federal U.S. Army Corps of Engineers NOAA Fisheries/U.S. Fish and Wildlije Service Bonneville Power Administration State Washington State Department of Fish and Wildlife Washington State Department of Ecology Washington State Department of Health Washington State Department of Transportation Washington State Department of Archaeology and Historic Preservation Washington State Department of Natural Resources Local Jurisdictions King County FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet Pennlt/Approval 1 Section 404 Permit Endangered Species Act Compliance Land Use Agreement/Letter of Notification ' . . Hydraulic Project Approvals ' 401 Water Quality Certification Coastal Zone Consistency Determinaticn NPDES Construction Stormwater Permrt Project Approval ' Temporary Variance to Noise Ordinance Franchise' Utility Permits , Section 106 Review (Historic/Cultural Resources) Forest Practice Penntt ' Shoreline Substantial Development Permrt Clearing and Grading Permit Right--0f-Way Franchise for umtties Short Form Clearing Permit -Geotech Right--0f-Way Use Permit Special Use Permrt Haul Route Agreement• Building Permit ' FS·3 Agency/Jurisdiction City of Covington City of Issaquah City of Renton City of Newcastle City of Bellevue FS-4 Pennit/Approval 1 Grading PelTllit Right-Of-Way Pe!Tllit Haul Route Agreement 4 Building PelTllit ' Franchise Ag,eement Level 2 Administrative Site Development PelTllit ' Public Works Penni! (Grading/Right-of-Way) Letter of Pennission (Geotech) Haul Route Agreement • Building Penni! Franchise Amendment Shoreline Substantial Development Pe!Tllit Clearing and Grading Pe!Tllit Right-Of-Way Use Penni! Haul Route Agreement 4 Franchise Agreement Special Use Pe!Tllit-Cedar River Trail 5 Clearing and Grading Penni! Right-Of-Way Use Penni! Haul Route Agreement • Building Penni! I i Franchise Agreement ' Clearing and Grading Penni! Right-of-Way Use Penni! Haul Route Agreement ' Building Penni! Franchise Agreement FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet Agency/Jurisdiction Pennlt/Approval 1 Other BNSF Railway Pipeline License Puget Sound Energy Land Use Agreement '·' Tacoma Water Crossing Penni! Seattle Public Utilities Utility Crossing Permtt ' Temporary Use Permtt (Lake Youngs Trail) 2 Notes: 1 -This table lists the key permits/approvals known at the current time. Ongoing agency consultation may determine that additional approvals v.wld be required. 2 -May not be needed; need would be determined during ongoing consultation. 3 -Because of the linear nature of the proposed project, more than one permit may be required. 4 -Would be obtained by the contractor. 5 -The City of Renton advises that approvals may be required from the lnteragency Committee on Outdoor Recreation and from the Washington State Department of Transportation. This would be confinned in ongoing agency consultation. Principal Contributors to the EIS k C1\SCADE ,.,,,,,.,.,,,,. The individuals listed below were principal contributors to the preparation of the EIS. For more detailed information about the education and experience of the principal contributors, see Appendix C. HDR Engineering, Inc. Mike Stimac, PE Marc Auten Megan Bockenkamp Ron Grina, AICP Karissa Kawamoto, AICP Fusan Lin, PE, PTOE Bonnie Lindner Joshua Shippy, PE Pat Togher, PWS Barb Whiton GeoEnglneers, Inc. Gordon M. Denby, PE, PhD Jodie Lamb, LG, LEG EIS Manager Environmental Scientist Environmental Scientist Environmental Planner Environmental Planner Transportation Engineer Regulatory/Permitting Lead Transportation Engineer Wetlands Scientist Technical Editor Senior Principal Project Geologist Historical Research Associates, Inc. Denise DeJoseph FINAL EIS: Tacoma-Cascade Plpellne Fact Sheet Project Archaeologist FS-5 Draft EIS The Draft EIS was issued on December 21, 2006. The comment period for the Draft EIS ended on February 2, 2007. Cascade received written comments on the Draft EIS from federal, state, and local agencies; from the tribes; from non-governmental organizations; and from private citizens. The comments received on the Draft EIS are addressed in this Final EIS. Final EIS Date of Issuance April 26, 2007 Locations to Obtain Copies of the Final EIS The Final EIS is available to the public online at www.cascadewater.org. The Final EIS is also available on compact disc for a cost of $2, or hard copy for $40, from the following address: Cascade Water Alliance 11400 SE 8th Street, Suite 440 Bellevue, WA 98004 (425) 453-0930 Copies of the Final EIS are available for review at the following libraries: • King County Library System 0 Fairwood Branch 0 Maple Valley Branch 0 Covington Branch 0 Kent Regional Branch 0 Issaquah Branch 0 Newport Way Branch 0 Bellevue Regional Library • Renton Public Library • University of Washington Suzzallo Library Subsequent Environmental Review The following studies may be performed and plans developed once an alternative is selected: • Erosion and Sedimentation Control (ESC) Plan • Wetland Mitigation/Restoration Plan • Biological Assessment (to meet Endangered Species Act requirements) FS-6 FINAL EIS: Tacoma-Cascade Pipeline Fac:t Sheet .k_ CASC:AOE • Critical Areas Study • Stormwater Pollution Prevention Plan (SWPPP) • Spill Prevention Control and Countermeasures (SPCC) Plan • Traffic Control Plan • Phase I Environmental Site Assessment • Phase II Environmental Site Assessment • Compliance with Section 106 of the National Historic Preservation Act Background Documents Technical reports, background data, adopted documents, and materials incorporated by reference for this EIS are available for public review at the following address: Cascade Water Alliance 11400 SE 8th Street, Suite 440 Bellevue, WA 98004 FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet ,·, ,ie,: ',!< I~'' FS· 7 >>From: ".Johnson, Ken" <Ken.Johnson@METROKC.GOV> <>>To: 'Highlands Neighbors' <highlands_ncighbors@hotmail.com> >>CC: "Crawford, Curt" <Curt.Crawford@METROKC.GOV>, "Isaacson. Mark" >><Mark. Isaacson@METROKC.GO V> >>Subject: RE: Thanks for your call! >>Date: Tue, 7 Feb 2006 16:43:32 -0800 >> >>Ms High, >> >>Sorry for the delay. As I said before, I do not have the expertise in the specifics of many of the issues you raised. so have had to consult others here in Water and Land Resources Division. I myself haven't been to directly view the recent slide, but understand that it has gotten some attention from some of the drainage engineers. as is reflected in wme or the responses. The following are your questions copied in: >> >>l) To what degree did the 4 most recently cleared subdivision sites Evendell. Libc1ty Grove, Liberty Grove Contiguous and Nichols Place) contribute to this event? >> >>A: Evendell, Liberty Grove, Liberty Grove Contiguous and Nichol's Place all front on 160th Ave SE at or near the intersection with SE 136th St. All four of these projects have detention systems and do not infiltrate their runoff (they arc located on relatively impervious soil layers). The outfall from these projects appears to flow south then southeast and eventually west in conveyance on SE 144th St with eventual discharge into the creek next to 154th Pl SE. It is unlikely any ol' these projects contributed significant recharge to groundwater and to the landslide that occurred near SE 148th St and 158th Ave SE. In addition, the clearing of an area has a mLtch greater effect on runoff than on recharge, and can actually reduce recharge because of the increase of impervious pavement and removal of shallow perched zones of groundwater, especially at the locations of these developments because of the nature of the subsurface in this location. See the response to question 11 for additional information. >> >>Also, you should note that some of the older houses in the area are (or were at one time) on septic systems --such drainfields contribute water to the shallow groundwater system. This is not the case for the newer construction such as the 4 subdivisions, which are on sanitary sewers. >>---------------------------------------------------------------------------- >>2) What can be done to minimize future comparahlc events? >> >>A: The landslide at SE 148th St and 158th Ave SE was groundwater driven. in that there was no surface runoff until the groundwater expressed itself on the slope. We believe that this event was mostly a natural occurrence --similar landslides probably occutTed throughout history since the Cedar River cut its valley and left this slope. It is hard to work against natural phenomena. and such landsliding is mainly a problem for the property owner on top or beneath the landslides. King County, like other jurisdictions. tries to limit development in areas like this, through its >>landslide hazard c1itical area regulations. >> >>Our records indicate that there is some possible, but minor, human element in initiation of this slide. A reconnaissance of this drainage in 2003 documented trash and "yard debris and other junk" in the area that failed. >>This trash may have cont1ibuted to the failure by restricting groundwater discharge, loading the slope. and by preventing establishment and growth of vegetation. So, general maintenance/ cleanup of drainage channels and >>vegetation establishment could help forestall a landslide temporarily, but would have little effect against the deeper, overwhelming, natural driving forces that really cause these landslides. >> >>if propc11y owners are concerned about landslides regarding a slope on their own property they should consult a Geotechnical Engineer for recommendations. Weathering. sloughing, and even collapse of slopes is an ongoing natural process. Without site-specific information, it is unknown where the groundwater will express itself and thus initiate slope instabilities. Given such uncettainties, and the great expense to study and remcdiate a slope stability problem, it is prohably better for some property owners to wait until there is a better indication that protection of the >>slope would in fact be necessary. MAIN FILE COPY >>----------------------------------------------------------------------------LOs0JJ)li >>---------,---------' ---- >>3) This slide occurred in a Category 2 Critical Aquifer Recharge Zone. By what methodology and based on what datasets was the boundary of the Aquifer zone set? >> >>A: The Critical Aquifer Recharge Area was mapped using regional-scale maps of suti·icial geology and soils, estimates of depth to water, and protective designations such as Wellhead Protection Areas and/or Sole Source >>Aquifers. The specific vicinity of the slide was mapped to be a Category 2 mainly because the surface soils arc glacial out wash materials (Vashon Recessional Outwash or Qvr) that readily infiltrate water. With any regional scale >>mapping or interpretation, there are going to be errors about where exactly the boundaries from one zone lo another should be drawn. There are methods for revising these mappings, and they are being revised on a long-tenn basis. >> >>You should note that at the hillside in question, the regional geologic map shows a dense geologic unit (Vashon Till or Qvt) underlying the Qvr which prevents much of the water from flowing to deeper zones. so this could be >>allowing (or forcing) the groundwater to 11ow out to the slope in this area, and thus make the slope more susceptible to landsliding. Some of our personnel, who examined the slope soon after the landslide. report that the Qvt is not present at the immediate location. However, they did report that the landslide slope does show a Qpl" layer that is also a low perrneability geologic unit (generally lying deeper than the Qvt) and which similarly limits the deeper infiltration of groundwater. >> >> You should also note that further north, away from the slope, the Qvt is mapped to be at the surface, including in the area of the four developments you discussed in Question I. In this case these parcels probably contribute little recharge directly on their sites. If Qvt is at the surface, then there is no Qvr at the locations of the developments, so there may not be a near-surface aquifer way to communicate groundwater from these locations to the landslide area. >> >>We don't have the regional scale geologic map available on our web site, but you can see the best present King County geologic map via the UW area: >>http:// geom,1pn w .ess. was bi ngton .cdu/indcx. php'/toc=maintoc&bod y=scrvi ccs/maps. htm > ><http://geornapnw .ess. was hi ngton .edu/indcx. php?toc=mai ntoc&bod y=serviccs/maps htm> >>(The map is very large so you should have a high-speed connection to view it.) >>---------------------------------------------------------------------------- >>4) Has this event "pulled the plug" on the aquifer recharge zone? >> >>A: No, we do not think that this event has "pulled the plug" on the aquifer (this applies to the entire aquifer rather than just the recharge zone) --i.e., we don't think that subsequent recharge will just flow out immediately without building up (such as happened at the High Rock site near Monroe). >>As mentioned in the previous response. there is a layer of Qvt or Qpf that impedes deeper infiltration. When recharge reaches this nearly impervious layer the water above it moves horizontally, and usually flows out at >>lower elevations as springs along the hillside. The small amount of material that was lost due to this slide has not substantially reduced the storage capacity of the aquifer, nor has it opened up a major channel for discharge. >>Because the slide probably has not pulled the plug on the aquifer, a similar series of rainfall events will likely produce a similar result of infiltrated water seeking an expression on the Cedar River Valley slope as it did this time, and perhaps initiate further landsliding. >>---------------------------------------------------------------------------- x>>5) ls the aquifer recharge zone now at higher risk for settling and subsidence? Should property owners be aware of such a risk 9 What can they do to prepare for such occurrence? >> >>A: Subsidence should not be a problem on the lop of the plateau as long as piping" docs not occur within the landslide scarp area. (Piping is the erosion out of soil rnatc1ials by continued water flow from a hillside --it occurred in the big landslide that temporarily dammed the Cedar River a couple thousand feet west of this slide, after the Nisqually Earthquake in 2001 and local landowners had gravel "shot" into the widening hole to stop the piping.) Our field personnel report that there had been evidence of piping that occurred immediately after the I andslide. but these "pipes" >>were dry soon afterwards and no more erosion was taking place (the little bit of seepage that continued was occurring further down the slope). >> >>Note thut subsi·tience is not an issue regartiing the recharge zone further back from the cliff, but only a local contiition above the slitie area. A greater threat is the soil movement that can be a direct effect of landsliding, with the properties at the lop of the slope starting to move along with the soil as it begins to fail (even if the houses do not fall >>tiown the hi II). Property owners along and close lo the bluff edge should be aware of the possibility of landslitiing at some Lime in the future, and contract a geotechnical stutiy or their property if they want to get some >>kinti of reassurance. Again, this does not apply to the bulk of the aquifer recharge area, away from the bluff. >>---------------------------------------------------------------------------- >>6) Will the aquifer recharge zone he able to store future rainfall, or will the water continue to shoot out the side of the hill? >> >>A: The aquifer appears still able to store future rainfall. It is likely the short time and high rainfall amount was the cause of an overllow of the localized storage available underground. This is similar to having a bowl overflow when too much liquid is poured into it. When the groundwater has achance to spread out it will reach the appropriate elevation for the flowfrom the slope to reduce or slop. But like a bowl, if you put too much waler in it, it will overrlow. (This question appears to be the same as Question #4.) >>---------------------------------------------------------------------------- >> 7) Under ideal circumstances. what can property owners in lhe aquifer recharge zone do to minimize future similar events'> What development standards anti practices could be set in place to minimize future comparable events'/ >> >>A: This landslide (like many others in the area, throughout history) appears to be a natural event driven hy rainfall, soil type. soil geology, anti erosion, rather than a mistake by any one individual or group. lt is a complex interaction and a concerned property owner may want lo contact a Geotechnical Engineer for a more complete evaluation of their own propetty. >> >>Without knowing all the causes and interactions a conclusion for the best development standards and practices cannot be determined. >>---------------------------------------------------------------------------- >>8) What arc the exact locations of all the slides cunently being monitored (or resulting from the same events as the largest slide)? >> >>A: We are aware of the following landslides in the vicinity and have investigated them but no monitoring plan is in place at this time. >> i. 14911 SE 145th Pl >> ii. 14217 SE 146th St >> iii. 13715 139th Ave SE >>---------------------------------------------------------------------------- >>9) How may we correctly request maps of the drainage features upstream of each 01· these slide locations? >> >>A: For now control and water quality facilities outside a highway Right-of-Way contact Dave Hancock at 206-296- 8230. For drainage features inside a King County Right-of-Way contact the Depa11ment ofTnmsportalion at 206-296- 8100. >>---------------------------------------------------------------------------- >>lOJ What is the communication model by which the lessons learned from theseevenls arc communicated to DDES so that future subdivision applications are reviewed with appropriate consideration of the circumstances that led to >>these events so that future negative events can be minimized? >> >>A: As in the answer to Question #7 (and other responses), we believe thatthis recent event was suhstantially natural. We already have regulations to avoid infiltration too close to the edge of a potentially unstahlc slope. >>In generaL across the extent of King County. we want to encourage recharge infiltration, tu preserve the groundwater resources that sustain stream flows and fish habitat. However, we already try to avoid allowing infiltration too close to unstable slopes. >>---------------------------------------------------------------------------- >>1 l) Some precipitation is captured by re/detention ponds, some flows off asxsurfacc runoff and some soaks into the .ground and becomes ground water, recharging aquifers. Clearing of vegetation accelerates the speed at which >>precipitation and some surface water soak into the ground becausetrccs/vcgctation slow this process and abo capture some pf the water fortheir own use. I don't know how rapidly this occurs, but certainly therewas a direct connection between massive volumes of rain and the hugcincreases in the groundwater that apparently precipitated the slide. I >>can't see the 11aw in the logic that clear cutting acres and acres of groundxmay well have contributed to increased volumes of groundwater in thcaquifcrs and that this happened much more rapidly than it did when thetrccs/vegctation were there. It seems to me that rain slowly seeping intothc earth would spread the increase in the volume or groundwater over agreatcr amount of ti me and reduce the probability or a slide. >> >>A. Jn general, development of a site causes less water to infiltrate andmore water to leave the site as surface runoff. Ohscrvation of these foLLr projects is consistent with this generality because surface water was seen leaving the site from the flow control facilities long after the actual rainfall has ceased. The surface water that leaves these sites is >>conveyed as surface water to the stream along 154 Pl SE. While a small amount of this water may infiltrate in the roadside ditches, the vast majority of surface runoff was safely conveyed away from any area where it could have >>contribllted to this landslide, perhaps even all the way down to the Cedar River. >> >>It is correct that removing vegetation can affect the hydrology or a site. Usually. a vegetation-covered site will infiltrate a much larger percentage of rainfall than a cleared site. However, the top layer of soil under the >>vegetation, especially in forested areas, is much more important from a hydrologic standpoint. The variahle ground surface, vegetation and ground litter slows the movement of runoff across the land giving it more time to >>infiltrate. >> >>The near-surface soil in the area of these developments is derived from till Qvt) a soil type called Alderwood soils, and very different from the soil Qvr. or Everett soils) that is present near where the landslide occurred. >>Alderwood soil has a very slow infiltration rate and tends to resist additional moisture. These four development sites capture nearly all runoff in the drainage catch basins and detention system. Tt is not immediately apparent that water infiltrating at these sites would even reach the landslide area. >> >>In short, because this landslide was a groundwater related incident it is unlikely that the mentioned developments had any influence on the cause of the landslide. >>---------------------------------------------------------------------------- >>Please feel free to share this e-mail with your members or anyone else. Also, feel free to contact me if you have further questions. >> >>Yours. >>--Ken >> >>Ken Johnson >>Water & Land Resources Division >>Dept. of Natural Resources & Parks >>201 S. Jackson St.. Suite 600 >>Seattle. WA 98104-3855 >>Internal mailstop (MS): KSC-NR-0600 >>Web: http://dnr. metro kc .gov/w I r/wq/ groundwater.him >><http://dnr.metrokc.gov/w lr/wq/ groundwater. ht m> >>Phone: (206) 296-8323 >>Fax: (206) 296-0192 >> >> >> ·'~ -·. -. ... ~?~----~ ~ ·: ... .--i{, -~,i {, " . /' RE: Evendell L03RE038 and Nichols Place L03P0015 From: Highlands Neighbors (highlands_neighbors@hotmail.com) Sent: Wed 8/09/06 9:19 AM To: Paula.Adams@METROKC.GOV Excellent. '"!:'f'.:c-':,d: ·.,::-,·--1 • C.A.R.E. -Citizens' Alliance tor a ResponsibJ_e Evendell n'.: '1,:t-:c:::.T ,/,,::, r-.,1r., ·Hi '-h _-,,ur r,,:-,i;i'."!b:)r:=-:1 fnr onr ,_-:nnm1_1nit\·. w~w.t~gtlandsn~i;~h8~s.cr; >E'rorn: ''Adams, Paula'' <Paula.Adams@METROKC.GOV> >T~: ,rHiq~lands Nei7hbo~s'' <tishlar1ds_neighbors@hotmail.co~~ >Subject: RE: Evendell T,03RE038 and Nichols Pl.ace L03P001S >r)at_c: '1,!crl,? A.11G :20ni:=: C'l?:1-::4:J -:J7C)r: > ~ram le~ally obligated t~ dcr:t1rnent in wr~ting th3t I a~ resy~~d~ng and when vou will be atle to review the records. >-----Original Mess~ge----- >Frcm: High L:.nds NC:d ::/:1b:Jr:c: [mail to: high] cinrl:s n2i.gt-:C0rsl1f°'.(:;t-ma i 1 _ r:orr.J >Sent: Wednesday, August 09, 2006 8:23 AM >Tc: AJar11s, Fac:a >Subject: RE: Evendell L03RE038 and Nichols Place L03FOG15 >:::ARE ~Fr) 2,r_ 2·jJc" >Renton WA 98059 >But. Why? >I am concerned about the potential unanticipated conseque~ces. Specifically, I do r1ut intend t:J incur ~nv 11nintcnd~j ~est~- >I'm 3ure that w~ dis211ssed t~at you ~ould merely gathe~ the ~esc11rccs and t~Pn, 1_1pon yo~r notification, our ~olks would come down to the ODES offices and review the files there. At that ti::ne '.'IE ,,_;ill =·ho_-:,::,e ,.,,:hi,::--h do:=-::1rnen"'.::s -c_:J c:,:ipv -d:id thus t!-1e le";>:'l c,f tirae and e:--:pen.s.:-:· :.ai·c:: arc-- willing to expend in this effort. I expressly DO NOT rey~est er authorize ar1y activity that will 8bligat0 ~AR? tr ~ny fin2n~~~J responsibil.::.t\· ot~~rwi2~ > >TLa.nl:s, >g >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what >'.,,;<·--.-,:-:an, 1,c;it-h ::)i_Jr --i,-:,_i9hhcrs, tcr c:ur ::)nmu::1.it·.-.. _ >www.highlandsneighbors.org > >From: 1'Adams, Paula'' <Paula.Adams@METROKC.GOV> ~re: ''Highlands Neighbo=s'1 <t~ghlands_~eighbcrs@hotmail.con~ > >Subject: RE: Evendell L03?.EIJ38 and Nichols Place L03P0015 ~nate: Wed, 9 Au~ 2000 07:58:02 -n~n~ >Ov.. I'l: Etart wcrkin~ snit. ··-----Oriainal Mefsa:~----- > >From: Highlands Neighbors [mailto:highlands neighbors@hotmail.com] >:c:-;ent: Tnr:sdi1'/, .L'..1;.i-:1."'t-()2, ;.:::,:,()() "3: l_(', PM > >To: Adams, Paula '-·Cc: i~::=i.:::-.,::1.~n, S"'.::eph-:1~iie; >1il'?s, Joe; Pray, ,J,::ff; ::::i11r.n, :<,:-:,"'1·;r."ff1; C"':lcat.u:n, > >Tim; Tm,:nsend, Steve; Hammond, Terry; Scharer, Bil~; Moo:::-e, Bernard; --Dvl-:e:m,=:in, >:1ke; C)mb1.1ci.'":'rn,~1r:; S,~ander.s, J.::.rn; G3lldJJhe.r, '/,"t:r1(_L·; Su1JL.:., :....1 ;;1\/..:...1.; -'iJ' _ii('., [,J-~t JO, -C v1aitinc1 tn sl:"e if al::__ our i .s.sue,, cculcJ :::ic rc,nlvf:rl at_ t:1e meeting scheduled fo:::· Thursc.L:lY .-:..··'°':·;_ir1-i. Hc,'..·'='·:f:'r, :,le?,).C'-~, 1::-1:::~:.,-i.,t,-~ni -)-_,-_-I ,-1rr. f·1r.,~ti-::ni:1;r ::__.~:tr9>?ly ·-1:--: ::i :";_1,:ili,...=~t::::::: l-_>::'t-.>:0 ~1:?L \"JIJl" depc1rtrnent a::1d my comm1_:ni t.y. ':'h1:s, T:J:::m ccns·"1ltation ',1,1 ith the re::;idenls wt10 ~1av1:: suffered the _:_mr·-c>.-:-:t-.~ :::f cr::-n:3tr1.1,::-.-:-~c-r_ ,-1t ... _r:e: E~.·,--r::k_l::__ -1:--1~'. ni,:'.rols Fla-=e r::ro~"='--'t_ ,-:1.r>l. i:i 1.::_._TLt f ··.-:::1_ .imp~n:::ling departure, v,'e re-ilera.le cur reques: (.Auqust 1, 2-:J06) tor oocu:nenta".:icn: > >Drainage: >\'JP. request 3 c-: al::_ :>::.rri=?ct'.c_T'? m~:-.:,:,111·c; jjr0°'--:tivc~ fc-r dr:~ir.,:.·J"':": r2fsr.:::n-:-e.-j in th.:.:. [ICE'~ u:osponse transmitted b:'./ .Stephanie Warden on ,Tuly 27, 2006 via email to us, along with all relev3n~ corr~sponden~~- > > >?i,.~.tbact 'Ji,;,la:::ic:r.::---:: > >We request copies of al: corrective measure directives the [1LE~· .:<?sp.1rise trr-12:n.ittE-d b:,: Stephanie Warden en ,_T1_1! all relevant correspo~dence. tor setback violations reterenced in }r:-nE -,,j,1_ em,:il t::) 11s, a:or.9 ;,)j-'-f. > >Addition3lly, last week Ms. Thorbeck wrote to CDES personnel, Bill Shaerer, Bernard Mcore 0~d T~~ry H~nm~~~, ... ha~ the uni:-.s on lots 19 and :o tave been sold a:1d a2ked therr1 to ~ro~id~ explanation cf the apparent inconsistency between your response below and the fact that units ha· .. ·c-, be,,:T. s-~!~d. Ms. Thorbecl: has s:-.ill recei'ied :ie.=..tr.er ,:;J_~kn.:·,,,,,le-::_·lr..re-ml:"nt c,f ':-hi::-: ,,~_.-::::,nrr.uni..::-3.ti,:n nor a~y answer to ~er inquiry. It seems l1igl1ly unlikely that a residential lender would approve fina.n:::.=..n:: f-:):::-3. ch,ell curr"?ntl'/ nr::t 7li,-=1ible tci re,~·1::i\"F:' <::in cc(:up-:J.ncy -::ertifi,:·a--::e. ~-'i~ formally request substantive explanation of the discrepancy as well as fnr why Ms. Thorbeck :cntin11e~ ts be 100 19r.1.;rc,j. _, ·-,,~cde Vic,lation Comr:la.::..nt: >We request all relevant documentation associated with this code enforcement complaint. > >Unprofessional and unresponsive staff behavior: '">Th,::, Telephcne ?r<::"'.::c,c-:-:-!l:> ha,.TP be..c::r: pr:-,,._;--jj._-:-,d. Th.-1r:k yc:11. ll:);_..,:,,:-,,:cr, a.s ;-.'c sta:_ed pr;-.-'Iic,usly: l;J;:,- fail to comprehend your reasoni:n9. When citi7ens submit complaints, and despite repeated ~~llc:w-11p c0~tac~s vie e~ail and teleph~:ie, nPv~r rPCE~7e a~knowledg?~ent of r~:eipt, ~~~·t1 l~s~ a status update, by what s~andard can this conduct be deemed prcfessicr1al or timely? > >Also, >-all > >-all we ncv,· request these documents: buildi~g f(:Otprin~/:~yout ~rop8sals t~at hav~ b 0 8~ docume~tat~o~ related to drainage, flcoding or ~he water £~r bc-h ~~t~~ ,-:::1hni.t:tr-:---i movement of any and all non-sewage >>-all documentation related to grading and bulk earth moverr1ent on both sites >-cill HCA rela.t~J du,,_.uP~-rtl.dLi<.:.:·r1 >>-all documentation related to the homeowner restrictions for drainage, fenci~g and l 0.nri2 1~·apin ',: > > ·,\\''? ur:derst3;-1d that y,.-::-u '.1,1-;_re a st,1ff/ri?:-::-:::-,1.1r,:e ::::h~1J_:_en\Je. 'T'!"J:rE'":f,:":,rc, :.-,·c· a,;rr,;,:: tn ~:::---112 suggesticn that the comprehensive ra·V'I file set (bankers' boxes, etc.) should De ::;uffir.:.:ient for c:1.ir purpc0es 3.nd 'r<ai'>1e any e;-:pP-t __ :t.:,ticL f,_,r DDE.S staff tc I s_i ft 1nd sort_·' '.1--::~ ·,'-'i 11 sPr,d residents to review and choose which documents to copy as soon as you tell us where and when. > >Further, we understand that it is riot likely tt1at the documentation will not be made .=-:;',/?il-Jble :c,r our revieh' bef.-:i::-e the meetinJ ,--::: ':'hursda::/, .Z\l.10'USt. \0J0 cic r2q11":;e:t th-1t t'.""F- gathering effort begin now, so that additional delay may be minimizRd 2nd documents can be ,·e\'~cv-H>:i ,JS S(1:_1:1 as pc:=-:sib:c::. If it ·,dll f."J::--.:..litatc y,--::nr c,peL=1tic:1s 1 ~-ff m,:'..': 1::~:2n be? aJ::.· . .le t··_· review these materials in batches as tl1ey are made available to you by individ~al staff ~t:~ml:)e r .,· >Please let us know as soon as possible what arrangements we might expect. > >Thank you for ycu efforts in this matter, Gwendolyn Higt: -president > >C.A.R.E. -Citizens 1 Alliance for a Responsible Evendell . cioing 'fllhat >'::'o: s:eµLc.nie. 'v,!c, rdE°:n@METROKC. c.:iov ,.,. ; :.-:,'::-. n:_ 1 ":" .-? '1t,FTV'.%". r~c·/, ,T;..;, ff. P .:-a "/r.'HETRCI<:~. r~·':':'', · , E 2 .~ J .3.:i. [, 1rir."·HETPC!<~. r:.r_:;•:, '-::' i:n. Che::i.t·-1meME'::'RCKC:. COV, > >Steve. To1•m::se:1.d13METROKC. :_.::;ov, Trorry. Hammcnd(~METRCKC. GO'J, '.~ i 1 --. S,-:h -j ;r r,'1! 1E:':'~.CI<t_·. r:,J.' I P-? rn,;j rJ. r+-: --re=:. '.]M?TR::nc::r. r:y;',', ' . Mi k"--'-. :•·; }:.com, ::·1(.!Yf,T!:iOK·'"". ,---;c/.' I p,31_1] a. Adams1~METRC·KC. (~OV, > > >Ombud.srnJn@M~TFOKC:. c;cv, ,}i:11. 5::i.:1ders(JMETROKC. GOV I :,,;<?n-i::,-. ,';,-: l I -,Jf,crrt-1ETP/;:-,:r:. ':;n':, >>>Subject: R~: Evendel: LU3REJ1A and Nichols P~ace LD3P0C~5 >~:=i.t:e: '~ue, 1~11, ;-,._-_1,.1 :::,enc ~-'.'1: o,··1:4':; -n1nr1 > > >C)ur i.ni_-iaJ rc_..si=<-:·n.s2 i.:: atta.:: .. ::tii-:cd. \,"le leak fc,::::->.1-~1rd tc, !>~_.,,,i,;1r.'in-:i "':he .:-equl:'::ot"::-J m-.::lti::'r.:...al.3 soon as possible. >>>Thank you, ',(>,\1 e:1ebl ·-ni H.:. ,~1r >>>president > > >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doi~g >·,d1at_ \0.'"7; CctL, ','.,.:'._tf: 01.~":'.' r.ei,;;hh:-!.".::'.S, f;:-!_:-:JU.r cc,mrr.uni:-0 ; > > >www.highlandsneighbors.org > > >>From: "Warden, ">'>To: "Hi?hL'inds Stephanie" Nei·;ht::=i.:-s 1 ' <Stephanie.Warden@METROKC.GOV> <LigLlar;,Js nei~..1hb(.:::r::-c:(lh:-::1tm3j_J. cr:-ir'.l°" > > >>CC: "Miles, Joe 11 <.Jce.Miles@METROKC.GOV>, "Pray, Jetf" > ,lef:. Fr2y0~-!ET?.OK::·. GCJ':h·, "Dunr., Rf:'c:t·::;an" ':'->'·<R~,:1,Jtin. D11n::.r1~,1ETROI<C. GO > > >>1'im'' <Tim.Ct1eatum@METROKC.GOV>,''Townsend, Steve'' > "C:he3tum, >< 2 t '?',T'":'. TY,.,TlSl:'r:d:JHETROI<C'. GO\T-,, "H,:-inrnond, T0 :· rv" > > ·-, ·,.--,1 "'::-r.:-y. Ha:nrr.,--::,nd0~1ETROKC. (;en.->, "~,~·!·1.::1::::f: r, Bill'1 > > >><Bill.Scharer@METROKC.GOV>,''Moore, Be~nard 11 > > > > >><Paula.Ad2ms@METROKC.GOV>1 "OmbuJsmdrt 11 > > >><Ombudsman@METROKC.GOV>, "Sanders, Jirc" ><Jim.S~nders@~ETROKC.GOV•,''Gallagter, Wendy''> >~.--,Wendy.G~11~Jh~rraMETROKC.GOV ·,1'Spot1r, David''>> >><David.Spohr@METROKC.GOV>1 ''Spohr, Dav~ci'' <D~vid.Spohr@METROKC.GOV> >>St1b~ec~: E-:end~ll L03RE0?8 ~nd Nichols Pl~28 1n~pn~1~ > >>Date: Thu, 27 ,Jul 2006 13: 05: 53 -0700 >>>>Dear Ms. High: >>>>Thank you for your e-mails expressing the interest and concerns you AlliaDce fo:::-a Respo~sible Evenrl~J.l, ~r C.A.R.E., ha7e ~ith the Evendell, Place, L03POOLS, developments. >>T ~1nderst0nd ~·c11r :on~erns fall into the fo:l~wir:q :6tegories; > > >> > >>* >>* >.> ··.:---Dr,: i r.,"l·J'~: > >> Draina·:rc:c. .Z'.djacent structural ciamage Selb6cl: ·ri::,l0tior1.' Encroachments Onf11lfill·~<I [-!2ari:v1 E:<aminer re,T-li:::-e,:J miti·"Jct:i,::ri Cude violation complaint f!np:::-of~ssi:,~~J ~nd 1Jnr0spn~~ivc .st~ff h0h~7:.0r and the Citizens' L03RE032, -:1:id Nir=-h.:::·~- ~->Du.:-ing th~ ~ir:t~r 0f :005-~006, Land Us~ Insr~~t~~ Tire ~h02tcn, cf the Departm~nt s~ Development aGd Environmental Services (ODES), addressed the matter of controlling surface runoff w~th the ~ve~j.~l: deve:0per/buil~er. Tt:ey discuss~J LSi~0 c1.1t:c,ff .;wa:es to di~~~~ surface .:-unoff toward the ruad coll~ction system. The required stub-outs at the catch basins ~ere i~stalled dc.:-i~g p:at const~ucti8n. > > > > ~>L3nd ~se Ir.specti.cn 2t~tf c0~rdinatcd with the Bu:.ldi~g Inspectior1 3e~ti~n '.BIS: 5taff, to assure the plat drainage design conformed to the building codes. B~S Inspector Terry ~l,1:nrc0nd_ i.s:=:1_1cd a ,::,:-;,r~e:::-ti.:in r .. ctice dire,=t:.n:;: '::".t'.e b·Jilde:c ·::::J brin,-0 '::"he :'..ot (:lrc-1ir:.a.,.;r>: .is.°'11;:;s L:1-~ compliance with plat engineerinq plans. No further occupancy approvals for these homes vdll be :ne::'t r.' :..l[ l ·-ie BIS .i11sper_:.=Lc__;r f>c:~12 r;.:,1 i ·J;:cr:t:ifi-'?:1 vfru issued Dc·~h \7 ,:;::::;:)dl dnd 11,Titten cor::-e::=ti::in r,c:-.iu:s :-.::-:i '.""h0 bui ;d<:J. jfl\" __ . __ ':"J.":·c i.r;·-3_ ti,; c_·':'rc.-·i:: . .:..~.-~ ·ir~-_"t:· r-,c.-_-'.l_llt:: .. r:.-} f::-,-:-:-1 -::hi:cc n:n,·:'f. > > >> >> ·:_'c_;11 :v-,-·ferP:1CI? ~:.-_,:1:-,tr1_:,_--:t_l;-:_,::1 .:-u:-·t:-:_,_~it'/ ,·::-c::1i__:_~::,j_n<J f·-,:::_·,;·,}:C.rt >;indi_<;,0 ;::; SCF.i dana=:e.s t--, :: [_,--:;i.co,-.. Clains for damages are a civil rratte~ between property owners. If yo~ hdve a claim fa::-damages ir,·,T,-:l~.~in,:i-cc,r.st.r;_1-.--:t::..,_-,r_ 1:--:ti·::.-~:, ~;lc-,-L>'°' .--c;1:t:rr.it it ·::Lr2·~·tl-.: tc L-i~ i-:-·.,:c::l·:..:-p~::::-/build.,::r ~>-:-u:nd 81:_il+- Homes for resulLtion. >>>>?lease submit aGy c:aim for destructicn cf ad~a::=en: landscaping or crees caused by earth- rr.c:,·Iir.q ::qnir;,mE::--i'.':-t_,::-_. -th<? ,:::J.r::7C:-" I ,:mer /t:uild-?r. > > >> ··Setb~c~ vi()~Ot~orn > > >> ~>You referenc~ a fcuLdat~nr. f::-:i:1r fe9t from an adiac~nt pr0pert\· l~r1e, b11t do ~ot give its location. Af~er Leviewir1q tt1e attachments sent with an e-mail dated June 28, 20C6, we assume th'? l':",t l.='..ne i:::= in ~-h':? Ev-:?ridell Flat, tetwccn lot 19 ,:nj -:-r:f:': T:"lcirbecY.. prc,perty. We Jr":' cd-2( assuming this is where interior setbacks (between :ots 19 and 20) appear to be less than 10 ff:'.c:t. T2::.·ry 1-hmm:::-,,:-id h,:--.s i.s:-::u2d :i. -='.:ir-rectir:n :1c,ti:.::e re,~i...:.:..rin,? the b1..:.='..lclcr t,·_, r~-establish "'.::he property corners through a survey. ODES will lake actio11 if tt1e survey determines the setbacks ,3::::-":' inade111ate, and ,:-;,c,~uparccy 1,-.'il.: r_,-;t_ te r::rr311~,=,d L;.ntil UH':-n:.,3tt7r is res.")~·-·e'.J. > > >.> ·; > F.r ,-:r-::i2ch11.e1c L ~- > > >> >~The e:--i~roachment i5sue becamP 3~pa~ent d~ri~g tte 0~rJ.y ~c:nstri;cticn ,Jf the deter:ti~~. vault. The developer/builder did not have permission, or a construction easement ~ram the adjacent: prcperty ~wner t,J proceed. Ott3_ning pernissio~ is the re~ponsitly of tte deve~ooer. When the developer did not produce documented permission, the work was stopped by ODES. A plan ,~·h3n-.-:;e '-'-'d0 rl='quired ,=ausin·:J t:1e buiLic-:r tc:-1.1.se cor1st:ru'.::ti-::,r1 t<=;:>,~·hr1i.:~;_1F?0 :ha'::: dij nr,t r"'·:::i1lir-:. excavation past the property line. > > >>Unf~lfilled Hearing Examiner required mitigation: Your letter suggests the HeaLing E:(aoi~er's ~cnrli7icns reg~rding ~tree: treP~ were n2t sati~fied. > > >> years after rc~::-:irjina. developer has posted a financial guarantee to assure the work will att3ched e-mail fro~ ,Je~f P~ay be perfcrrned. (See the > > >> >>rcd0 Vicl0tion Ccmplaint: Your let~er re=erences ~ conplair.t. > > ~~~P 3re unable t0 determi~c whi~h 2cmp~ai:it #390 1 ' (filed May 23, 2006) is unfamiL .. ar to us. t:.h'.:s r:i;.1tt':'r, 'de \0 Ji.ll dddress j_·_ '/C1 1J are r'?:erpncin9, as tJ-.e phrase, "Re:":. If you have additional inforrnaticn to clarify > .> >> >>fJnr,r,1fc::=;si::)n0l .-1r .. J n:tr'?.sp:)n.sive st:::i.f:'.: behavicr: unprofessional and unresponsive. Y·=u:-letter .:._nc1.:.c:ate::; ,.-.,11r .'<taff has b"?f:-:-, >>>>After interviewing DOES staff, tirnel· ar.d p:-ofessi0~~1 m~n~c:r. ~~ I have deterrnir1ed that our responses were ha~dled in a all code requirements. ,,~·escl v-2. > > >> 'h"i ]_ l As stated above, ,::c:-nti.r.ue t•;. n,nit-or this prcje-=-:: fc.r ~:::rr:p:.i::in-:::12 civil matters are not wlthir1 DOES' authority to ·.,;l th >>Th_ suh8i 0:i;;ic:n pr:--.,je,ct fl le.s are d.1,:3.ila.[-.le fer pub~i-::: re 0 .rie,.-,·. If :./0·.1 wish tn 2r:::'ledul~ an appointment tc review these materials, please conlact the ODES Reccrds Center at 206-296- cr;g( .. Please ,:r1r1tact Bui~ding Inspection staff 3t 206-2~6-6630 for ~cc~ss ta the hu:.1c1.:._n~ f i::..2s. >>>>If you have additional questions, please cor1tact Bernard Mcore, Building Inspections Sur,e rvi s Dr, vi a. '::'-ma_:_ 1 at =-erna rd. Mc,,~,rc '.!met-_ 1"\) r:,~. ')O'I <·:rr.3 _:_ l '::::,:Br::-r-r.c.rd. M:.>c:r ':c 1:lmet r:::i k.,:::::. <]'JV·· ,.Jr > >telephone at 206-296-6762. >>>>Thanks you again for taking the time ~u e-mail. >>SL!:"phctr;.;,.e Warder_ · r_:_r'?·-·t ·:.,::: L~::;,r1,:::·--:-1v=,1,t ~.t !:,:-•-~' ~Dl'C.r:t--1nC":: fo'.n·;i r:-,v1mrc:'J-.-1-'. ~-"'r·,-i_ "":C·." > >> ·-----Or~~i'1al r~~~s~-,~----- > >>From: High:ar_ds N~ighbcrs ·.c:,._:1-. Th 1 1r::,:--:!.,-i'J, ,:-11ly ~, r~ailto:~ighlands r_eighbors@hot~ail.com] > >>Tc: ·,\lard'::'r:, St<::phctnie >"·r1,: [li_,,:rhl:-J.nri:::· n2.:_r_1Lhors~J---.r::+:::na.il.,:-·1ff_; tvJi.2.1:?s, _1e;e; Prc,y, ,Jef:'."; D1_::-1n, > ·,.·-,ppa'1:1:-1; ':';"\<?c:t1_:rr, Tim; Townsend, Steve; :-Iarrunor:d, Terry; Scharer,> > >>Bi:;_l; Mocre, Berna.rd; Dykeman, Fike; A6ams, Pa1Jl3; Crr.b1-~;:i:3:nc1.r:.;-:: ·-or+-i-.-01911.ln, '."oth:i,'; sa-1d2r2, ,1:rr.; r:a:_1.1ghr;:::-1 Vi>:ndj-'; ."pchr, C:-:i,.dd > >>Subjec~: RE: COMP~A;NT: ~vendeJ_l L0:3RE038 and Nichols Flac2 LO~P0015 > > >>Gacd Morning, Ms. Warden, >>>>Can you direct us to the correct person and/or method for contact and answer to the ::;imple ·:1u1:=sti·:)n b':'l::·,01,? I .~rn, ::.:,,::·rr'/ to 1.;r_;.".:_h~r v·:::,u, f:,ut /Pt .:1ncither ·,\'eek ~-1,.3 oo.s.~e 1.:l a.nd ·,.'.'""" continue to be 100~ ignored. >>>>Your assistance is greatly appreciated. >~·Tl"'.-:L::1Y.. ::_,;nu, >>>>Gwendolyn High > > >->C.A.R.E. -Citizens' Alliance for a Responsible Ever1dell ... doiru] v;h3t 1,1 e can, ·.\'itf'. cur ru?i·JhlYir.s, f::,r ::,1Jr ,:-o:mr.uni--::· >>www.highlandsneighbors.org > > >> >From: 11 Highlands Neighbors" <highlands neighbcrs@hotmail.com> > > >Tr_;: h i·?hl a~1ds _rt":oir,:rhbors 0 he ::nail . ::cirr., c.1::::e. M.:. les SIMETROKC. GOV, > > >> >Jeff.Pray@METROKC.GOV ~> ~rr: Re3ga~.DLnn@~ETROK~.G8\1 , Tin.r~e-3.tum@METROKC.GOV,> ~ ~- >Steve. Townsend@METRO:<:C. GOV, Terry. Hammond@METROKC. GOV,> > >> >Bi::..l. Sch<Srer@l"lETROKC. GCV, Ge: rnar:J. Mnc rr:0M?Tw:::,Kr:. GC\T, > > > >Mi ks. ::,ykemn ri.@ME.TROT<C. GC'-7, St epr.a:n i e. :·.Ya rdenClMETROKC. G8\', > > >> >Pa11la.Adams@METROKC.GOV, Ombudsm~n@METRCKC.GOV,> > >> >Cathy.Ortiz-Olguin@METROKC.GOV, Jim.Sanders~~ETROK~.GOV,> >We~dy.GallagtPr@METROKC.~~V, Davij.Spohr~METROKC.G~·· > > >> >.Sul:::,ject: RE: COMPLAINT: Evendell L03RE038 and Nichols Place .> :::...o 3 ['0 Ci l" >>>>>Date: Thu, 20 Jul 2006 08:34:26 -0700 > > >> >Good Morning, Mr. Pray, >>>>>I: has been a mor1tl1 since the submissicn cf our official complaint with no substantive respcnse. It has t,ee~ one week sine~ I ser1t tte inquirv below. Since we have ~ct ::-e~eived an· word from you ur1 the simple question below, I thought it time to reiterate. >>>>>''We lock forward to the written response to cur official complaint. It should be hc-dpf1.1J t,--;. -111 in r--·rep--1:·;:iti,_)r. f::)1· t:lP Au'.]·.Jst l(J1_-i, rr.eetinq. t,:r.2n .·?!-":-:ill '1J'? ezr,e::t it?" > > >> > ·,:,.:ur respcn::f? ·,'-'(·,ul-J be mC.'-3t apr.:reci3.ted. If I 3.r:l ncit add::-':'ssir.q thi::: qnF>stir::,r. t.::::· :-he. appropriate person, please direct me to the responsible party as soon as possible. > > >> >Thar1k you, >> >Gwe~dolyn Hi~~ > > >> >C.A.R.E. -Citi=0ns' A~li2n~e fer 0 Respcnsible ?~en1e_ > > >> >wha':: '(,'e can, with our neighbors, fer our c:::irr,munity. >> -A~w.hiJhlandsneighbors.org > > .>> .doi.:r'] "' ~·> >>From: "Hiqhla11ds Nr?.i'}hbors" <hir::it.:ar_ds_neighbor::·01--ic)tmail .•.:o:n" >>>>>>To: Joe.Miles@METROKC.GOV, Jeff.Pray@METROKC.GOV '·,>CC: Rs-aqan. [1c.nn19ME-r::,.or-<:c. c;:)\T' Tim. C:1,:a t. u:n@METRC.H{C. I,(;\' I > > > ', >>:3te'Je. Townsend@METROKC. GOV, Terry. Hammond@METROKC. GOV,> > >> >>Bill. Scharer@METROKC. GOV, 8e~n~rct.Mo8re@ME~RCKC.S0V,> ~>Mike.Jvi:em~~3METROK:.G01', Stephanie.~arder10METROKC.GC'.', > > >> >>Paula.Adams@METROKC.GOV, Ombudsman@METROKC.GOV, > ->:> >>Cathy.Ortiz- DJvij.Spohr@ME'fk8KC.GCV '.:.:ut,,--je,·_·t: R:::: ~Q\ff'T,J'..."'."~~T: E:·.·.c-·n:::ls-J2. T.1---,?.EI \:.: .:',nd ~-)j,~h:,-:-: Fla-:-- >> ">>LOJPOC ~ S . !:',_, > > >> >> > > >> >> ·-·-:--'-;,_.,'f_1,1r1I·'. :/,.-,,: f::--,.:::-t'.--1s- >> >> '>'\--Jc ~"-:)k fcr:dc~r:--J +_--, t:bf? ·,/';-;__·jtt:"'r r~.-::;~--:-,~_,:-1.'"'P ..... ,-. ~,1.1r cff.::.,::ie.l ,mc-l:-1.ir,.t_. >>>>>It should be helpful to aJ.l in preparation fer the August 1o·t, meeti:1g. > > >> >> '·>Than:< yo1_:, >>>>>>Gwendolyn High > > >> >>C.A.R.E. -Citizens 1 Alliance for a Responsible Evendell . :=k,in:;r ,.,,,h:=i.t ·,o,1e C'."<rt, ',\1 ith c-ur nel.,Jhb-:.,r:o, fc:-::::-c;11r ,_--:mnr.rnn.::..t: >> >>www.highlandsneighbors.org >>>>>>>From: ''Miles, Joe'' <Joe.Miles@METROKC.GOV> >>'>Tn: 11 !-H:/1la:1::l.s l·Jei,:_:rht,,r:-r::-" > > >> >>><highlands_neighbors@t1utmciil.com>,r1 pray, Jeff 1 ' >>><Jcff.?ray@METROKC.G~V'· > >> >>>CC: 11 Dunn, Rea9an" <Reagan.Du:--m{3METROKC.G0'1>,11 Cheat.um, Tim">> -~-' t eve. T0'."Ht.~l::'rt:.l 1:lMETROKC. G('."/ ", "Ha:rnTi·:~,ri bill''> > _>> >>>:Be~rt~~d.Moore@METROKC.GOV>,''nykPm~n, ·<Ti~t.C!)~~Lum0METROKC.GOV>,1'T0w~send 1 St1~~0 1'> Terry 1'> > >> >>><Terry.Eammond@METROKC.GOV>, "Scharer, ~"~Bi:l.Schar~r@~ETR8KC.GOV>1 ' 1 M8ore, Bernard''>> Mjke''> > >> >>><Mike.Dykeman@METROKC.GOV>,''Warden, Stephanie''>>>> '"<St.ephanie.Warden@~E1'ROKC.GOV>,''Adams, Paula''> > > >> >>><Crnbudsrnan@METROKC. GOV>, "Ort i:-Olguir., ··.··, >> >< F,11: ::_ .-1 . f'-.,--:!.-1.r.1s rat,JETROKC. ::,c'/ >, "Crr.budsn;_-iri 11 Cathy''>>>> >>><Cathy.Ortiz- c1,1uir.i:?ME'TRO~<:C.GOV>, ":")and0r.s, ,Ti:n"·->>><LTi:n.~~ander::::0ME':'RC:\C.GOV>, 11 Galla·:_;:1er 1 \'iE-n-=I··" > > >> >>><Wendy.Gallagher@METROKC.GOV>,''Spohr, David''>>>> >>><David.Spohr@METROKC.GOV> >>'S8tjec~: RE: ~8MPLAINT: Evendell L03RED32 3nd tli~h0l3 r::.a·:e L03P081S >>>>>>>Date: Tfu, 13 Jul 2006 14:45:37 -070C >>>>>>>Ms. High- >>>>>>>Our office is preparing a written response to your email regarding the Evend~ll/Ni2hl0s Pla~~ projects. Javid Sp~hr is cut ~f the 8f~ice until ,Tu:v :7. C·1r ,~ffic~ will coordinate with Mr. Spohr regarding the purpose and the agenda of the August 10th mPering ~pan his re:ur~. > > >> >>> >· >>>Joe M~l~s. F.E. >>>>>>>King County Land Use Se~vices Division Director Dept. of > -....,> >>>D~uel.opment an1 Enviranme~tal Ser~iceE > > >> >>> (206) 296-7179 ~" >>>j0c.mil0s@metrok~.?O~ > > >> >>>www.metrok8.gov/ddes >> >>>>>>>-----Original Message----- >> >'>From: Hiahl0nds Neiohbors > > >> >>/[mailto:h1ghlctnds ne1ghborsjhotma1l.com] ·,>-....,Ser.t: Th1.1rscltiy, ,J11l:,/ 1?, 2()()6 1: 3...., PM > > >> >>>':'o: Pray, ,Jeff >>>''~: Du~n. Reag3:1; Cf1~a~urr., Ti~; Townsen,j, Scharer, Bill; Moore, Ber~ard; Dykeman, Mike;>>>> .Ste,_:~; M~ l.c:.C"C., ,:,_-}c; > > ·,I-lamnon:j, >>>Warden, S~ephanie; Adams, Paula; O:nbud.smc,n; Ort iz-01,Juin, Cc1t::t·_,:; > >>>>>>>Subject: RE: COMPLAINT: , >J/l?,FJC:,l '· >>S~ndcr~, ,Tim; Gallagh~~, We~d~- Evendell LD3RE038 and Nichols Place > > >> >>> ··G0uJ Af~e~rt~cr1, Al:! ,> > >> ;.,>> '> ~ ~>>We hope ~~ery0~c h~d ,i ~~f0 a~d happy hcliday. It haE n~w be~n ar:Gther twr, w~ek~ sjnce last communication from you on this matter, so we thought 'e'le better check in. > >> >>>In ::h1--:: r:i.ca.ntin<;:;, I ha'/e t-,ad -:;e 0Iera l rrncin:"".'t.i,:e ~:cnversct:..icns ·0.,_tr. ·-r--fr. '~c~t-::-. :-I.,:-, t1.·1,· -·-:t Lf -J m---.--,-:-: --it:": 11:; f--r t;1:--;:ru~t ~,J (7pr., i..J·._ -f Ti+~. ~1ic ---:h cor~er 0f SE 128th ar1c 160th Ave SE) He ir:forn8 me that te l:as exter1ded i~vitaticns t~ r-er.c-;,-n:--1·-::-~, t-·1-:: l-1::1.-J ,_, .. -~t >-:-':'n ., i :...,•<l ,_,t -'lt_-:--r::1dc,:-,.c:. -~ > >> >>> .,,,::111 :_IlJ':::-S:.i·:n:~ -:~-d-~.1'· ,l~C: > >> >>>-Wha: is the action it.en l~st frcm the meetir1g descr_bed below? -:,-.:Lc1:.. _i_:_c· ht=--._1.-.·--:;··,1,-1t,·-i :irwl.:..n--:::~,-r t~i-:,.c.,:; a,.=--::ir.·.r: iti-:>!t:.':· >> >>>-Who will attend the meeting un F.ugust lOLh":-' >>>>>>>We look forward lo learnain the answers soon. > >> >>>Thank you, :..-o->>>(;:-'_:er:dclyn Hi::):": > >> >>> >> >>>C.A.R.E. -Citizens' Alliance f~r a Resr0~siblQ E~r~ndell > > >> >>> ... dcing what we can, with our neighbors, for our community .. ~> >>>www.hi~t1l3nd2nei~hbcrs.orJ > > >> >>> > >> ,>~ >From: ''Hi,J~lands NPighbarg'' <hiahl~~ds ~eighb2~s@t10tmail.com' > > >>>>>>To: Jeff.Pray@METROKC.GOV '-,',> >er_:: Reaqan. :Jur;n0L1ETR0I<C. GCV, T i:n. C'hl::'a.t :1mRME'::R1:J~C'. GOV,> > ··,> : -t t-: - Dr:-~;; >Steve. Tm·msend@METROKC. GOV, Joe. Miles@METROKC. GOV,> > >> >>> >Terry. Harrunondi'.'!-METROKC. GOV, 3ill.Scharer@METROKC.GOV,:.. ·,>> >Bernard.Mo·ire@METROKC.GOV, Mi~e.Cykerr~n@METROKC.GC~, > > >> >>> >Stepl1anie.Warden@METROKC.GOV 1 ?aula.Adams@METROKC.GOV,> > >> >>> >Ombudsman@'.'v1ETROK::, 1'.;Cl\', C'-3 th~-. Ort 1.7.~01 91.1 i ;---i (}~01F,TPOKC:. r,c::,v, > > >._'Ln. 2 a:-idr: r :=: 0 METRC'.<C:. r:;C;'/ 1 Wendy.Gallagher@METROKC.GCV >~ >>> >Sutie~t: RE: COMPLAINT: Evendell ~01RE038 and Ni~hols P:a~e > > >> >>> >L03P0015 '>Date: Fri, 30 ,.Tun 2C·0C: 1.J:::::5:4? -:::::o:: > >> >>> > > >>>>'>~ear ~r. Pr3y, > > >> >>> > >> ··,>:-',':h,-mJ--: ,,-,:.,1: f:-:ir ~/(::-ur sta-:--:us npdat.c-:. r,._s :/OU :n.1~; ',-;2.:.1 e:,:pe-:t, t~1ese is::cu<?:': are ,-:,f intense interest to our community anrl. inquiries to C.D.RE on the matter have Deen volumi::--ious. l ~n ?lad th~-w~ are ~c~ ~ble tc forward y~~r ·1Djate tc ~11r m~mb~rs bef8re the lo~a holiJa·.· weekend. ,,-. ·-,;, >Parti;-=--ularl' ir: liuht ·-:,f ':".L~ fc:\ct <:=-hat in::::;;.1fficient 1 inef£7 1·:t:iv7 C'r nc)::--1-7:·:istent communication belween your colle-:1gues and the i:npacted residents is cne of the chief concerns ide~tifieij in rJur complai~t; ,,rur update 3ppe0rs to indi~~~8 prog~e~~ th~t w2 ~11 ~~n appreciate. > > '>> >>> >We hope :"or continued pro1,:ires:s a.rid look fon,,:ard to learninq the actlcn it.ens and tin.~~ab.:.e th3t r~sult from t~e meetin0 you de3cribe belo~:. > > >> >>> > >':-> >Hc:'Je a ::.o,,-ely 11-, -1 ---:1~. , > > >>>>>>Gwendolyn lliah > > >> >>> >C.A.R.E. -Citizens' Alliance for a Responsible Evendell >. --, ... dcir.,=r v,.rhat 'e,'":o c-3.n, voith -::i1Jr :-1ei,Jhbcr.3, fer ct ':::cmm1.1riit > > >> >>> >www.highlandsneighbors.org > > >>>>>>>From: ''Pray, Jeff'' <Jeff.Pray@METROKC.GOV> > >>>>>>>Tc: ''Hi0hlands tlei~~bors'' ~hiahl3nds neiohbors9to~:nail.~orn~ > > >>>>>>>CC: •rounn, Reagan'' <Reagan.Dunn@METROKC.GOV>,r'Cheatum, Tim''>>>>>>> ·JT i.m _ C-h .. -::,1 t .iml~ t-·1E'.RC:(r. r;o•1:,, "T<::,h'Tl:: c-::-id 1 ? t .-.~vc" :, > -. >< ~; t eT7":': _ TY,'\:n.senj,~METFOKr. GCT-I>, "Mi::...=::· ,Joe"> > >> >>> >><Joe.Miles@METROKC.GOV>, "Hammond, Terry"> > >> >>> ~.>--Tr::rr~/.Ha.:nrn,-:,nd@t,~ET?.OK:~.(__;Q'J>, "'.:>.::ha.r:er, Bill"· '> >> ·""'Ei::..l,3cL'3.r':'.:.r0'.'v1ETR'.)KC.r;cr_1-., "M,Y)ri':-, Bernard''>>>>>>> >><Bernard.Moore@METROKC.GOV>,"Dykeman, Mike''>>>>>>> ·/Mike.Dyke~an0METROKC.GCV>1 ''N~:::-den, Steph~~ie''> ~ >>>>><Stephanie.Warden@METROKC.GOV>,''Adams, Paula''>>>>>>> ·· F,:.. ula.. l\dam.s C1~01ETROK-:-:. G·'.Y/> 1 "O:nbc:jsrnc..n" > ', ', > > <Crr.buds:n.sni_<J t·-'lE':'R8K('. :;ov -, , "~)rt i =-:)1,yJi r., Cathy''>>>>>>> >><Cathy.Ortiz-Olguin@METROKC.GOV>,'1 Sanders, Jim''>>>>>>> ->.>< ,-:--im .. S ,:c·1de:::-s@MET ROKC. GO'l>, "Ca.1 laGhe r, 'i-..!en.j,.,-" > > > ,,-,/We:·1dy. Gal 1 aqJ--:e r0METROKC. 1~cw·- > > >> >>> >>Subiec:: RE: COMPLAINT: Evendell LD3RE038 and Nichols Place ;>>> DatP.: > >> ·,>> >> > >> >>> >> '<Jr1 f_,',;:;;ha.lf ,-lf C.--:,F,~· .·":;":";-:ff ic -::;.]-_cp.j ir t)·.'? r,c:,.-:cr,,·n:,c: t jCtl:::.· .~,'.f1"':•C-:rr:..C:, p;.--;,-:::~r: ;-_- advised :tat 6 ~eetinq with all concerned st~f~ has beer rcqu0st0d by the Land Use Services L\i.-,,ii,;i:Hi L:.-r2,_·~.-_-,r, I··Ll-:>.::,. ':'1·1'? m':'Ptin•J :,_:i11 :,.-=-c1-:::-.·3'.·1-::i::--t_~,, ,Jfte~ +-h,:_ :1;-:·---:1·:rnin,J '.-1011(;-:iy. '':1 sure y8u will agree :he co~ccrns yo1: dcscrib~ cover a variety of discip~ines and issues. The mee~:_n-~ i5 ir:.tended :o -:iss1Jre ~0 o,ij-0~s th~m ~0nrr~h0~si~~1y i~ o:1r r~r1~· t~ ~t 0 r~:_gt~~r:_j NeighbO:.'.."S. > > >> >>> >>:n the interim, please be assured that the Buildir1y Ir1spectiuns Section {pa.rti·:::-ul::irly Berna.-:::-d t<•:::,::ne iind Terr~: H::1.rr.m;J:1d'., v,ith the a.st-,istanc'::' --:-,£ L;;r:d rJ:30 =n2p'::' :::t i-::,ri-~· (particularly myself and Tim Cheatum), have been i~leracting on a daily basis regarding the drair)aqe ~nd qradin0 i3sues ~elated t~ the plats and the tui:dj_ng pPrrrits. Terry is ~he fi~1~ person for the issues relatRd to the building permits and to my understanding has been in --:,x1~-:J.c:-,.,,;it~ the v~:rmi t:--c; 1 c1pplicc1r.t r~·J1:l.'1rl·/ o~.rer thc:.sr: ra;;t ;,--.r0.ck.ac;. > > >> >>> >> >>C:~~ 0f tte iss~es ~n your list of c~n·:erns invclves tt1~ ~l3c~~ent of ~treet tr~e2 required by plat cor1ditions. For your informatlon, plat conditio~s require the trees be i~stalled within o~e year of re~ordi~?-~~end2ll will .re-:i,~~ t~e end of that pe~ind J~te~ t~is summer; Nichols Place will reach the end of that period this fall. Both projects :1ave the requi~ed ~inancial ~~arantees and agreeme11ts in p:acs to -:l.Ssure ~his worl: wi]_J o~cur. > > >> >>> >> > > ....., >"·· > >Th,1 n k yc11 1 > > >> >>> >> ···>> >>Jeff ?ra·-: > > >> >>> >>Ser1ior Engineer ~' >>> ~>KC CQES ~-:l.nd Use I~s~2c~iGn~ .> > >> >>> >> '·'>> ~-~-----Or~gin~l Messag€----- > > >>>>>>>From: H~ghlands Neighbors > > >> >>> >>[~ai:to:highlands r.eighbors@hatmai~.ccm] > > >> >>> >>Sent: Friday, June 23, 2006 3: 08 Pt,~ , -...,To: Dunn, R1::aq21n; ZZGrp, E->::;3..:·ir.q Ezam.:_n"'-.rs Web .Supoor:::;: ·, >> Pray, Jeff; Townsend, Steve; Miles, Joe;> >> >>> >>Harrrrnond, > > ~ '· -....,>Tsrrv; Sr:-harer, Bill; tlio-:-)re, Bern-:i.rd; Dykeman, Mi ~'.e; '.-}ar,:::Jrcc:n, > >>Stephan~e; Adams, Paula; Ombudsman ) >> '~Subject: CCM?T.ATNT: Evenrlell L01RE01R ~~rl N~~~cls Pl~,:~ > > >> >>> >>L03P0015 > > >>>>>>>To Whom it May Conce.rr1: >> >>C'.-1e-:1tum, Tim; > > >>>>>>>Citizens' Alliance fer a Responsible Evendell is dismayed to repcrt tha: p~a~ti~~lly ~~~~y ~irgl0 adverse 0ffect th~t we pr0dictei in our ~nterventio~s 3r1rl a~peals possible resul~s 2f the ~7enJe~l ar1d Nicho!s Pl~ce proiect~ ~as indeed come tc pass. > > >>>>>>>The damage and expense that has heen inflicted on neighhoring residents has been unnecessary. and in every case, avoidahle. We submit the attached complaint and request a speedy inquiry and resolution. > > >> >>> >> > > >>>>>>>Work has begun in earnest on the adjoining Liberty Grove/Contiguous projects. At the very least we hope that review of these issues will minimize additional impact and expense. > > >> >>> >> > > >>>>>>>Additional photos and testimony will be suhmitted as soon as possihle. > > >>>>>>>Technical difficulties prevent their submission today. > > >> >>> >> > > >>>>>>>Thank you, > > >> >>> >> > > >>>>>>>Gwendolyn High > > >> >>> >>presidnet > > >> >>> >> > > >>>>>>> ... doing ,vhat we can. \\'ith our neighbors. for our con1munit: > > >> >>> >>wv,w.highlandsneighhors.or > > ><< 20060801 _ Evendell_NicholsPlaceComplaint.doc >> RE: Follow Up: Evendell/Nichols Place Meeting of August 10, 2006 From: Dykeman, Mike (Mike.Dykeman@METROKC.GOV) Sent: Fri 9/15/06 4:59 PM To: Highlands Neighbors (highlands_neighbors@hotmail.com); Warden, Stephanie (Stephanie.Warden@METROKC.GOV) Cc: kurt@soundbuilthome.com; deb@soundbuilthome.com; Spohr, David (David.Spohr@METROKC.GOV); Townsend, Steve (Steve.Townsend@METROKC.GOV); Moore, Bernard (Bernard.Moore@METROKC.GOV); Miles, Joe (Joe.Miles@METROKC.GOV); Nguyen, Viet (Viet.Nguyen@METROKC.GOV) Ms. High and the Highlands Neigt1bors, I apolcgize for th~ del~yed resp~,~se. I ha~e ezperienced ~n 11nP~p~~t0d f~~jly ~~0r]rn~y w~ich has occupied a lot of my time the last couple of weeks. We h~ve continued to make progress on the itr?m5 that ,/,e dis°'-::us::;,,-;d .-1t ".'".he:: r:cmmunit::/ rr.cc:tinq: Occupancy J'..pproval: DDES committed to withhold.i.n9 occupancy of the new houses in the Ev~nd~ll/tli~hols P~a~e p:ats Lnti~ tje dr~ina~e req~irem~~~s for th~ i~dividc2J lot i~ approved. The drainage requ.i.reme~ts for individual lots are the connection all roof downspouts 3nd yard Jrai~s to tte main storm ~rain in tt~ str~e~. T c0:nrritt~i at 011r m~0ti~g t~ rR~t:~ri~g a flow test for each required drain to make s11re that water entering ttat drain flows to storrn ::L::cti:--1 i:-1 the .s"'.::reet. :-?·.1b,3,::,q11t";nt.l1/, C:::JE:S has ap:s::,rovr:d ::;ccq::,an,:::y f,'Jr a :-1 1..i.I:lb~r of residsr.·-=:s.~. Tt1e DOES insreccor has verified that required roof and/or yard drains are in place and witnessed a s11c:--::essf11l t]c,,; tc-::st frc,:n ..:o.s.:-:h requi::-":'c:1 roof c..nd/c,r y3.r--::l. :Jr::1.in fc,r ·~hi-:' incL·.r..i.:Ju;:i: let prior tc granting f~nal i~spe,:tian appru~0~. Special Drainage Conditions: I discussed in our meeti.ng that there are two drainage sub-basins ir1 the ~vende::..l pL-Jt. mh':c rL:1,;rc di·.~i:iinq ""he: sub-basir:.s :')Cc1..:::s ~n ~,-=,t:s ~:', t:-lr::YY1h 21). _c:._ drainage variance was approved to allow the water from the new irnpervious surface 2zedted in t-h0 v,cst.,:-:r.l:_,,· .s11h-::)a.sir. .... :::-i =lr2in int,-:, the stc-r:n sys-':err: in t:-1,:.-i-°'".L3t'::'.:l·J .-::ub-b2sin. This i.3 accomplished through rci::Jf and/or yard drains on each lot that drain tc the .storm drain in the street. Ther0 are r.r p::-ovisiur1~ ir: the vari2nc~ fer ,:,::,llect..i.8~ of rain W6ter ~n tje varjs i~ the westerly sub-basin. After the complaint frcm the Thorbecks about water running 0;1_ tc their prcperty during coristru~t~or., C~ES asked S8'Jnd Built H)mes .... ~ 2onstr1;ct 2n earth b~rG t~ J:0~r water on the constructio~ site. Tt-:i:? '1;as acco:npl~_:-:;!--,c:::,d. :::1:l-::::-:>0q11r:nt.ly 1 :)()Enci ::311i.lt. !J,:-:,:ncs :'as submitted a p:ar..s ::=-har,ge t··,' construct a permanent sha:low swale along the west boundary of Evendeil to collect any yard dr2inagc in ~he wc~tcrn sub-basi~. Tte swale sl0pes t0 th~ sou~h and drains into 6 vard ir2ir at. the lu"'' point. The yard drain is piped to the st0rm drain in the street. J'..n Easement ar.d Co'is-r:.ant fo.: Drai:i-:1:::ie h;;is l-Y?e:-1 re::<;rd<?,J for tl-.e s1/1ale, y.-:-ir.--:i .j;·ai::-i, ar!'.1 ,jr::iin :;J.:..pc. Thi~ facility has been installed ond a flow rest from the yard drain shows that it dra~ns to tl1e s::..:·ect. ":'."h':' Thcrbt?::J::? h,~ee r-1 i :=-,i:::d cc,nccrn ,1t01:t f11t.1:::'.'':: l-:=ir.::is;:::-2.pin,J individual h,:Jm':' ,",1:1:1e.:::-::_. altering the drainage swale. As previously noted, the Easemer:t and Covenant of Drai~age is rc~·1r::icd ,1n ttc titles cf th':' affected lots. 8~ES :~i:l inspe2t the swale for ~8~D:ian~':' a: final inspection. After final inspeccion, any violacior. of swale drainage requirements should b':' referr-+-::'d t·:J tt-.e C,:;i:-:2 F,r,f r,> cncnt Sr-;(:t·icn a-2GG-~~(;-(i(;8C1 • Setback Violation: Ccncer·ri was tciised that the house on lot 19 in the Evendell plat is tco clo.se to the Th·:::irt>?·-=-Y.s r.::r·:•f=':e;'rt/. Tf:-? :::,:minq 1;·od":" .r:'":'quir>?.3 a r; ft sj::Ji=, ~/,Jrj .setha..-::k t:) The foundatio~ wall in this circumstance. The zoning code allows some projections within this r+-='qilired ::,etb,1,:-:>:::. ThP b11il::-lin9 .-.:odr: all,-),,.rs :::c.n:otn:ct.icn 1J.;-, t,--=-the prcp>?rty l~rn~ ',,'ith 1 b~1n tire resistive construction required and no openings allcwed for walls closez tt1at 3 ft to the rr·:::ipert~, :ine, ,,..,,hich i::: :1e..>t :.h<:? ca:::r::a here. r=1 ES r;;.;que.-~'::.ed that Sci;Jn:=i Built Horr,e.3 p~O'l.::.d2 ,-j survey shcwir1g tl1e property lines, foundation outline and setback lines for lot 19. This SGrvey was complet~d a~d ffiad~ a~3ilabls ~t 011r meetinJ. The s11rv~~-~hews -ha-the fc11njat~on i~ 5.09 ft from the Thorbeck's property line. The survey also shows the setback from the let 20 rrop~rt~-~i~c tc he 4_gn ~nd 4.91 ~t. whic~ is tac ,:lcse. Seve=al opti~ins are avai~able fer addressing the setback violdtior1 1 ir1cludir1g a zoning variance. Sound Built Homes has applied f,:=.r a =r:-,r.in·::r ,=ode var~<:n>->':' pr":c-apr::·l.i.1>;1t.:.,,r1 meet:.i.:EJ 1.m:jer a::tiv:ty ;"..06FM3i:;6. T:"°1'? rr.~eti.ni1 i.~ DciII1d,;Je to Neiqht:cr_:_:-i-J Pr1;p0::-1.""_ie:=;: ~.:everal neiqLl:Jors :v th!:' 2\:eririell/Nic:-101.s Place plat:3 Qa~:e -,~.",:1_.::_m-,:-1·:: c __ s t.--·,:1t,.:,r i--1:-1"":1~,; ---~1,--i::: r.,:::-~,pert.:'._e.·· cu::; .J r..,,..cc ill >f r·1:·1 .>f:'.: .:r,:.m the:=-:-1~-x·::? --:1,:-~n--x r:eTvy rain :':torn lo.st ,,,'int2.r:. JLJ!::S re;•re'::ie:1:dti.ve~ ctl U-:.e meet in:] expressed re'}ret over LJc ---J::rr:--t·~-V tf' .. -:_i_t_ -1.:1·_;,~y-1.c-: ,c;:-:r:;.::r.:..sr:,:;:,.j ,;1,c· ;-i ..:'~:'''111 -:_·.f •t-__:_,c.: l;:'\'Pl"1t. \'~ -'J(; :,·.1r b~.':'t ~:i--:-:::-.,·_,,--,-F. '-~-r_:rrr:_;~.r1r:-~-~ ,,s.1.:..tr, drainaqe re~1..:.:..remer:ls en site durinq const:ructior1. We alsc .s2id tr,a.t Sound Rul .L-:::. !Ic .. :ncs :1as -he :::,-_..c;p,_;r.5iJ::il.:..t:y f--=::: :-:::ru..:,::..i:m, .. ·.-\'ith th2 ·:-,•_k-··,':'.. Cle:';"·, l·!:>llerdY-?,:·> :·f Sr:-1.~:·1·:: B1_1-l~.': HTn<'=':3 ,,:,:1.- dsied wi.:h whom ~t Sou~d Bc.:'._lt to disccss a. damage claim troffi water damage dc:::ing tjis stcrm ~--•cTt.. D'::'b 'JC:1ve tLi:c'. --:::--1:·1:::act n.-J-:-:1<':' c:f ;,.:urt :·.;:..1.?,-:--n ,/;h·->.:-i:-1 b'?, r(:,1,::hc:l ,1+-,--r::~-J''-'~-:1'. Improved Ccmmunication: The Highlands Commun.it::/ expressed c::..i::1cerr1 thc.l there .:..s no formal ·c1ut.,l '._c: pr::ic:es:-:; tcr thr:rr. tc k:i.,-,,.,, ~-.'hat i:c:: -Jc,.:..n.;:-,:-;,re aft:::r pe:::mit'."'. ar'c:' i.:-;::;1.:.eC c.:1ti "'-'nst::1.1,:'ti-:-1n is started. CDES recognizes this concern and is available to include corrununity represental.ives in ~he pre-,:onst:::uction ccnf~re:1ce ar1d/~r 3t'.::end a corru1t1r1i'.:::' me~ting to JJrovide ir1fcrm6~icn rri-~r to the start cf construction for any future plats in the Highlands area. DOES will contact all ~ar'.::ie2 of record in this r~·Jarj. Improve Construction Phase Oversight: ODES representatives explained at our meeting that we h~ve ~ hi-Jh degre~ ~t co~2tr~c:t.:'._r,~ 0vers.:..ght fr0~ -h~ Lan1 r1.se :nsre2tion and the B11~ldin~ Inspeccion Secticn. We have numerous required inspections and are at a cor1struction site uften. H~we'ler, ;:e are not s'.::af~Pd r)0r do 1~e t1~ve the respo~s.ibi.lit•; :o be at 3 site ~cntin·1al~y and observe all construction activities. 1:0Je do v,ant tc· respuud to community concerns and complaints ~~d ap~r~ciate ~cntac'.:: fron1 th~ cowncni~\. if 'li0laticns 0c·:ur durina no~ wor~ina ho~~s er whe~ we are r1ot dble to be on site. We have responded many concerns and complai1:.ts regarding the development of the EveGdell/Nich-:13 ?~ace plats by phone, e-nail ~~d sit~ visits. ~e have met neig~bors on site a number of rimes. 0:1r goal is to ensure compliance with t~e codes. We feel that h'•"": hc1c_-e dc:ne ~l--.t1".'" r;r arr: ir, ".'".he p:,:-,-_,c:c~:=:s ,_jf d:";i1:.q tlFJt ·,,,,ith c:=i::-::h :::if t'.1,:: is.s·F":·.S +-[';,-::,-:1.--=i.-,-·-:: been raised. There are those who would like DOES to do more than the cede requires and we cart not de that:. Thr_:rc art~ th:'J.se v;h·'J ·,-.''.)".Jl=l like '.JS to req·,1i:::e le::cs an,j v.'<? ':,ill -2nf:::,r-:e -':1--.e .::-cde t:' the best of our ability. We gave out 3 list of names and phone numbers at our rneetinq f'.:.:·r ·--:-,:·1-::'.:tc::.:3 at_ LL:1 ES. I ',,,i.::..l in.::lud8 them ir: -:h.:..s -~·orrnumic-:J.ti::c~: Building Issues: Mike Dykeman ::::'(16-296-6761 Dc;rr:.,-:_;rd M:Jcrr:: Land Use Issues: Joe Miles Steve Tovmser.d 20E-296-72Cl4 .Z\,1c;1i:--1, '1,'e. 21.:.: cc:::.s dr.:.:--~·are a:-1-::l ·,_,e 20::· dc?dic..ct':f':d tc di i.riq c1 • . .1r iots ·/:i?l::... Plea.se :'.:e'::'l fre'::' t( ccnt-:J.~t Jny of us alJ0t1t any 0ddit.:..or,al :oncerns or question3 ~hat y01.1 may~~--~ Mike Dykeman [:i_\.'i.Si'.:-,n L_re 1~·f___,.r Building Services Division DepartmPnt of n~vel,)~ment ~ Envir~nme~tJl Servjces 900 Oakesdale Avenue Southwest Phorte F cl;.; : 2C6-296-6761 PS Several people met with Jue and n1e after our meeting to addr·ess indivici~al cor:cerns. We dre ·.,-,or:-~inrJ en these:; iss1_1':°.::' ori a ·~·.,:i.se? b'/ ·'dSC:O b-~.:.si.i: -----Original Message----- Fr:::im: Highla~ds Neighbo:::s '.m~.:'._ltc:higt:ands ~~iqhbcrs@hctm3il.conJ Sent: Tuesday, September 12, 2-J06 12:59 PM T0: ~3rde~, S:ephani~ Cc: kurt.@soundbuilthome.com; Dykeman, Mike; J.-: ?,t_c-0_;,:-_,; M:::icrc, Bcrn,1rd; ~-1ile:.s, ,T,::_.e;; t-1911J•.?n 1 Vi,;:,t Sd-::-1>:-:::':"': FE: FJ.:l:::.1s."-' Ur.::-: Eve~dell/t·-.Ji,_~::i,-::-,ls Fl:E~"=' Yler:'tir.'J ::,f Au9ust l:J, 2C:1 C1G Hello, ~1~. Warder1, Spohr, David; Townsena, It was good to chat with you last Tht1rsday at the UAC tor11m. I was encour~ged rhar you ir.ve.sti'::Jat.e ::he hulJu~i ur: :_L>::> r.:-i..::.r:·,:.;;.::es.':> re;>0r:. ',~·!-::: ~1ave beeri ezpec::i~HJ fc,r jus:::. ahc::ut. a nc)r.th. Tf .. -::,;:: sser:·.:'3 t,= bs -t:-!-'.r:'-m.::._:-,i::u:r. t:":~.::-.:1 r .1~1.-J '::iLS" f,=:,r .J.n'; ;,:;·..1:~:-:--t-·:i:1-1--i-.~;:._ ',~·:nr..1:r.i_-1-t-~':-'1 fr-1':': ··--:<Jr _.--,•-.-,.c"" .St.::·ar;(,:i<::ly, as evidenceJ Dy Ms. ':'IJ-:...,:::bec:<.'s e0.ail belo',,', suc:1 a L(J~; .:s nc,t. ::::rns.i.s:P.;1'!:" a.---:-:re::::;s a . .l (:~ [,[.::::: ,:·umn!!L_:__,.:tt .i .:1,· '_:__r:1_-:'-1 ,t:· __ ·_.r. :he words we Leard at 0~t~~t ~~IT~ ~-ti~n t~ tl1e August 10th rreetir1g were all quite r1ice. \-Je only wish ycu :ni.;rht -1°'-t1:,-_·11 1F:.'.-:": -J-.,"?rn .,..s,~~. We look fcrw~rd to h(;ar.::._nc tte CDES plon ct action to address the issues raised again al ~he A~gust 10 mee~i~-~- ThanK. you, Gw~ndo1yr High -pre3ide~: C.A.R.E. -Citizens' Alliance for a Responsible Evendell ;,.rP: ,:-:an, :.,.r.3..th onr r.r;i.,;;hbc,::'."s, fc,::'." '."'JiJr :::c,mnunl ... www,jighlands~e.::._gttors.~::'."J >From: ''Thorbeck, fenny 1' <thorbeck.p@ghc.org> .doing what >~c: ''Hig~:0nds Nei0hbcrs'' <~ig~Jands neishb8rs@hotmail.c~m~ >Subject: RE: Evendell/Nichols Place Records available for review >Da ... 0: '='1121 12 SP.':) ):'!IG (1P:IIG:~] -n7nc• >T'.1at's .interPst.::._nc. We havp Geisht8rs ~n cur backyard in the Nichol~ ~r;v(::,~prr0nt. those plats were approved for occupancy without drainage resolution! >Penny K. Thorbec~ ~Tcrt~ary anj 80N C~re Man~gPrr~nt >206-901-6124 ,8-GCO-Gl24 > >CCN~IDENTIALITY NOT~r~: T JlJt-?.:3:: >This message and any attached files migl:t ccr1tain confidential information protected by feder~~ ~nd state law. T~e infcr~at~o~ i2 i~teGded 01:ly f0r tte use c~ tte indivi~tral(s) nr entities originally named as addressees. The improper disclosure of such information may be .:1.1~..:e--=t t-: ::-.::._7i: ::->r c2::"imin-1.l p12nalti0.s. If ~rd::: rr.e:-ssJ'},C:, .-e-:-i,_--:hed ycu ~n error, ~:.>le.::i:,;e c,:;-r1lct:·t: the sender and destroy this messctye. Disclosing, copying, forwarding, or distrib11ting the ir1formatio~ by ur1auttcri=ecl i~Ji~.:..~ual2 or entities is strirtly p~nt.::._bit~~ l~ >From: ''Dykeman, Mike'' <Mike.Dykeman@METROKC.GOV> -,~r-.: "Ei ,;rh 1_ ;i r,rls Ne i ']hbc r .s" ><hi gh l.tir: :-:1:3 n1=' i ciht,cr2 (!hc-tmai l . r_· om>, <deb(l _c; :Y .. mdl::.,i_:_:_ 11:". hr.me, ',:err:> 1 "Sr.::C'·L.::: , David'' ><Cavid.Spohr@METROKC.GOV>,''Townsend, Steve'' ><Steve.Townsend@METROKC.GOV>,'1 Moore, Berrie.rd" 'B":?.:::rnrd.t·:,_::,:J~etlM£TEC)KC.C;;1v·>1 "~-1ilP::c;, ,Tew" ',Tne.M~ l --,:iM?.'TR'.")f<C.GC\'> CC: ''Warden, Stepha~ie'' ><Steµl1dnie.Warden@METROKC.GOV>,<kurt@soundbuilthomc.com> >S·.1b..:,c:,i::t: RE: F-:=,ll :frJ fJp: Evende:1/Nic:-vJL.:o I'lt1(:/:-' >1eetircg :,f AtF;rc.st l:J, >2006 >C,~t~: 1;-Jed, lh P.11,) 7Cl('f) 1 h: ~-(: .'.Jn -r);nn > >Gw,:::r-:d,.-_.J yn, We have been Thur:::3ay an::-J >Mike i. t ;'-'a:3 ,:i wcrking Fe id,c:;. ~~1le,1.'3·.1re? mee--:i~-::r 11;ie1 y,::-i.; ,ir:d th':::' ·::c-mr.1.1.1r:i":y qrcup last Thur::cda~.r evPnin;:r. on the issues that were identified at our meeting. I am out cf tl1e offi~e i:,.;, '.,:ill r-r:J-.:id0 ~;("";l} '1;i t;l a :;-JrC"}rE::'.3 rr?p-:=,rt ne;.-:t i,0l8'?~'.. >-----Original Message----- >Fr~m: Highl2nrls Neighhnr~ [m~iltc:h lands_ne.::._0htors@hctmail.~a~] >Sent: Wednesday, August 16 1 20C6 3:01. PM ~T0: d~b~3CGr1dbuilth8~e.-0~; Sp0hr, Davi~; T~~ns~ni, S~0 ~~; M~cr 0 1 >Rsr~~rd; Dykeman, Mil:~; M~les, Joe>Cc: Warden, Stephanie; kurt@soundbuilthome.com '.S11J-·j<c:,--:t: F'o.1.loh' Up: Ever1d'?::..l/Ni~·hc-l.3 P.2.21··~·":' Meet:.nJ r_·,f ;,ugu.:::t ~0, 2(:,0( >U"::::ir: A.'..l, > ', ~·i r:::: L ;· l :1_ c,[ a:l, ',,''2 ·,,.'c,11lcl like t,· tr~,rr th~ m~cti~J ~xpress o~r th2nks tcr _1_··r1, :c,r_-J "':" ··-,11:<~,.-J "~1 :-1': t f1dl ea'.~h t)t '/Cll h;icl ar: evec later ev'::'ni::-i'J. week. I live o~ly fr.-nt ::!.:.· ' 1:: .. ~~"i. : ' Ill -,1_1-=-."? :-:=: ; >P'-s M.:::-. S;.,:::ihr czpresseJ :.b1:::re, after so lor.g ~ tine for issues tu ren1ain outs:a~d.:.nq, it wculrl :J"'· nr.;·,-:-1.~--:,r.:::.>l·-::::-t: "::c:'::.;...:. £;::1_1 ·::-t-::?(:11 ti,r,n i:-1 ~,"v ,-.r.----:,~11::-1-,=;l:", TL.:.::_:. ::'"1Ll"'l.iL::.:i r~-::il::..v .-·:nl·,: i-_:::,:i ti:r, t_n hash through wh::J.t r_as g:Jne be tore. Ncnr. thPless, ,,,'e had -:0 .stctrl .some 1,,;here, ctnd I believe t~~ ~onv~rsation i~ ff r --::---_-::--_) .·-:=:t .--, -r"-. >.Jee? Mi1..'.:!.--:=:: "~.'}1-::,, .Jr.'."":! CJllr ::=:taff, are '.il":'di1_:at1-::1 ':. 1_,-. cic:1i:·1-:: ,r~·Llr l:·h:' ·,,,·c:l >Mike Myke~an: ''We do care.11 >Ceh 11,.-:,11,-:r:1.-_,c:·,:-:k: ":.'fe 3_:::-,c::, ·,-:imr::1itti:':'d ·1 be.:"_n,.:; g::i<::·:'. nei'-)hr>~·L>. :,J,-: '.,.-r.-:rnt tc de, the right tt-• .:.n·;." >Ri']ht-,-,f.:, I 'h'ant ti:·, be clear th,1.t ,,.re" 1:nc:.c:::stand ":"'.ha:: the ans·,\lers tc, that ::rc.~.st.:"_or; ',:i.:..l surely mean very ditferent things to DOES and S0ur1d Built. To clarify: >-What does Sound Built propose to 11 make things right'' for the residents negatively impacted hy th~ construc::ia~ a~ti~·.:.ties ~t the Eve~rlell and Nicjols F1~,:-:c pro~c~~?7 >Diane Kezele (water runoff, trees, septic system) Dave & Penny Thorbeck flooding, setback i:=;.,:-;ues, l::'ncrc:,:::1.r::hr1":'r:t, :::ir-:J.~n-1.;e ~rr:p::,y:err,"::nt µ;,:p0n.s0s, ::tr11,:-:t_ural da:na']e'.· '--~a· Hi::..l (.:'.L:>J.:"_n=:, tr1:::es, structural damage) Mary J'..rrn Huniu {fl::)Odinq, drainage, $15K basement damaqe) Ma:::.·sfu:1. R::,lli:i.•Jer f_l,::-,:~1dinJi C:L=ilFle: ~3ta::hiw.:"_aJ.-:: (d::-.ciina::e' '-Wh~-doe:~ DOES p::-·:pose t~ de tc: >Improve communication 'A'ith res~dents? ',Irr.prc·ve .:.:::):'iStructi,x1 p~·1a:3s '.)'-.r"?:::.-:?i·Jht ir: 0rder t-c) mi nimi 7;:; f1:tur':: >setback violations, flooding events, encroachments and collateral >:st-n.1,.-::+-11r-1J d,1ma9,::-:? -~r,,;0, -~r.=. en::-:cnra,-:Jed t~1at '::h":' cc·n'Ii:::r:::,;:1t>:m :1as f.:..n::12-1'-_: be!::'::i !::'nJ2:,:i12d. \''7'":' >look forward to continued productive discourse, and hope for honorable >re~0lutior: of all t~1~~~ is2ue2 > >Thank y 1 :··u, >Gwendolyn High -president >C.A.R.E. -Citizens' Alliance for a Responsible Evenciell ... doing 1..-Jhat '.· . .-,re can, 1·:ith cur nc:':.qtJ:·or::-:, for our ccmrn:.1nit·,.-... >www.highlandsneighbcrs.org Evendell Plat Level 3 Downstream Drainage Analysis ~r- cfrd?t fir~ 5( f r pu1 lfr FILE COPY Rec~,veo AUG 2 ,q zooz LAN~lus l.UL!N j y E SERVICES LD1Po 016 Submilled to: 900 Oakesdale Avenue S.W. Renton, WA 98055 Prepared by: Haozous Engineering, P.S. 9957 171" Avenue SE Renton, WA 98059 Tel. (425) 235-2707 rax (425) 254-0579 August 26, 2002 .\ Drainage Complaints Drainage complaints along the downstream systems were investigated at King County Water and Land Resource Division as part of the Level I Downstream Drainage Analysis submitted with the project's preliminary technical information report (TIR)(Haozous Engineering, June 2001 ). Since the preliminary TIR was prepared, neighborhood comment forms, collected by C.A.R.E., have been reviewed for information about drainage-related problems in the basins. Of particular note, flooding from the ditch on the east boundary of the Evendell site has been observed by Mr. Bret Bowden, a resident at 13 814 160th A venue SE. When flooding occurs, water crosses the road and flows onto Mr. Bowden's property. Mr. Don Gregg, a resident at 16046 SE 142"d Place, has also observed portions of 160th Avenue SE inundated by flooding during the past 5 years. Methodology A hydraulic analysis was conducted for conveyance systems along both 1601h Avenue SE and 1561 h Avenue SE. The conveyance system along 1601 h Avenue SE was evaluated from the east boundary of the site for a distance of2,300 feet. The conveyance system along 156th Avenue SE was evaluated from a location due west of the site for a distance of 1,900 feet. Both systems consist of driveway culverts, pipe segments, and open channel. The model Stormshed™ was used to predict runoff rates from contributing basins and to model the hydraulics of the conveyance systems. StormshedTM is widely applied in similar projects and has been adopted by Washington State Department of Transportation for assessing and designing highway conveyance systems. A field survey of the downstream systems was conducted by a licensed surveyor. Ditch cross sections, pipe inverts, catch basin rims, and road surface elevations were surveyed to obtain data for the Stormshed™ hydraulic model. A summary of each structure surveyed is provided in Table 1. Basin boundaries contributing to the conveyance system were based on aerial topography and the Cedar River Basin Plan. The basin boundaries were field-verified and divided into subbasins contributing to various branches of the conveyance system (Figure 2). The easterly basin was divided into seven subbasins (el -e7), ranging from I.I to 33.9 acres in size (Table 2). The westerly basin was divided into eight subbasins (wl -w8), ranging from 1.2 to 16.3 acres in size. Cover types and land uses in the subbasins were based on a 1990 aerial photograph and updated for recent development by conducting a field reconnaissance. The basins consist of mostly single-family residential land use with housing densities ranging from about I to 6 dwelling units per acre. Land uses and cover types are shown in Figure 3. The east basin was estimated to have a total of 124.4 acres, with 35.6 acres in forest, 20.2 in 2 pasture, and 68.7 acres in single-family residential land use (Table 3). The west basin was estimated to have a total of 48.3 acres, with 6.5 acres in forest, 7 .0 in pasture, and 33.4 acres in single-family residential land use, and 1.4 acres occupied by a church. Based on King County Soil Survey (U.S. Department of Agriculture, 1973) soil types in the basins consist of Aldcrwood soils. The Santa Barbara Urban Hydrograph (SBUH) model was used to model the runoff from each of the subbasins contributing to the conveyance systems. Curve numbers for the subbasins were based on the weighted averages of the various land uses in the watershed (Table 4). Hydrographs for the 2-, I 0-, 25-, 50-, and I 00-year storms were routed through the Stormshed™ hydraulic model of the conveyance systems to determine flooding locations and their approximate return periods. The Evendell site and other contributing areas in the basins were modeled under their existing land use conditions. Travel paths for each subbasin were based on aerial topography. The type of flow, flow length, and slope used to calculate time-of-concentrations are summarized in Table 5. Rainfall amounts of2.0, 3.0, 3.5, 3.75, and 4.0 inches were used for the 2-, 10-, 25-, 50-, and JOO-year storms design storms in the SBUH model. Modeling Results Details of each subbasin modeled in Stormshed are presented in Appendix A. I for the easterly basin and in Appendix A.2 for the westerly basin. Model results for routing the design storm hydrographs through the drainage networks are presented in Tables B. l throughB.12 of Appendix B. Table 6 presents a summary of flow rates at key locations in each of the conveyance systems. A summary of predicted flooding, for all surveyed structures, including open channels, is provided in Table B.6 for the easterly basin and in Table 8.12 for the westerly basin. The locations and return periods of flooding related to pipes and culverts are identified in Figure 4. Many of the driveway culverts and pipes along 160th Avenue SE flood at a return period of 2-years (Table B.6 and Figure 4). Several reaches of ditch also overtop at this return period, likely as a result of constrictions in the pipe capacities. Modeling results are consistent with drainage complaints from residents along this reach of the drainage course. Similar modeling results were obtained for the westerly drainage course, where several culverts and catch basins were predicted to overtop at 2-year or I 0-year return periods (Table 8.12 and Figure 4). Conclusions Several flooding locations with return periods of2-years were identified in the downstream conveyance systems. Flooding in the east basin that overtops and inundates 160th Avenue SE is considered a severe road flooding problem by the King County 3 Surface Water Drainage Manual. Residential structures have been flooded at 14928 160th Avenue SE and at 16046 SE 142"J Place. If the finished space or the electrical/heating components of these residential structures were flooded in the past, the flooding would be classified as a severe problem. Otherwise, flooding that occurs at these residences is considered a nuisance problem. Channel erosion observed along the east boundary of the property at 16046 SE 142"" Place, downstream from Pipe P-110, has been a persistent problem over the past several years and would likely be considered a severe erosion problem. Continued bank erosion is likely at this location, with potential for reducing the capacity of channel sections further downstream where sediment is deposited. The flooding that occurs at the adjacent residence is likely related to the reduction in channel capacity due to sediment deposition from the eroded banks. Based on modeling results and information available, flooding problems in the westerly basin would likely be classified as nuisance problems by the King County Surface Water Drainage Manual (1998). We found no documentation indicating that 156th Avenue SE or residential structures along the westerly drainage course have flooded in the past. However, a drainage complaint (Complaint No. 97-0318) related to flooding due to a plugged culvert, was not available for review (Haozous Engineering, June 2001 ). Proposed Mitigations Level 2 RID standards are currently being proposed for new development in the westerly basin of the Evendell Plat. No additional flow control or other mitigations are therefore required in this basin to reduce project impacts to nuisance flooding problems. Level 2 RID standards are also currently being proposed for new development in the easterly basin of the Evendell Plat. With severe flooding and severe erosion problems located in the downstream drainage course, additional measures to mitigate draioage impacts could be required. For the severe road flooding problem along 160th Avenue SE either of the following mitigations could be required: • Providing Level 3 detention in the easterly basin, OR • Upgrading the downstream conveyance system along 160th Avenue SE to eliminate road flooding. This would likely entail replacing driveway culverts P-117 and P- 116 on the west side of 160th Avenue SE, cross culvert P-115, and pipes P-114 and P-113 on the east side ofl60th Avenue SE (Figure 4). For the severe erosion problem along the east boundary of the property at 16046 SE 142"" Place, the Level 2 RID standards provide the mitigation required by code. Other types of mitigations to reduce erosion at this location, such as bank stabilization in the eroded section of channel or Level 3 RID standards, can be imposed through the King County Surface Water Drainage Manual under certain circumstances. It is our opinion that either stabilizing the eroding section of channel or the use of Level 3 RID standards would mitigate project-related drainage impacts that occur at this location. 4 ·I If you have questions regarding these analyses or need additional documentation, please do not hesitate to call me. Sincerely, Edward McCarthy, Ph.D. P.E. Hydrologist 5 .j 9957 17 ]:st Avenue SE fru (425) 254-0579 August 26, 2002 Mr. Michael Romano Renton, WA 98059 (425)235-2707 Centurion Development Services 22617 8th Drive SE Bothell, WA 98021 Re: Evendell Plat -Level 3 Downstream Drainage Analysis DDES File No. Dear Mr. Romano: !fa'. !) . Tiris letter report documents the methods and results of a Level 3 Downstream Drainage Analysis requested by DDES for the Evendell Plat. Separate analyses were conducted for the two drainage courses from the Evendell site. Project Description The Evendell Plat is a proposed residential development located within the Renton Highlands area of unincorporated King County (Figure 1 ). The proposal for development includes building single-family dwellings on approximately 12 acres (Haozous Engineering, June 2001 ). Road improvements along SE 136th Street are also proposed. Level 2 RID standards are being proposed for the onsite stormwater facility as is required by the King County Flow Application Maps and recommended by Lower Cedar River Basin and Nonpoint Action Plan. Site Description The site is located within the Orting Hills subbasin of the Cedar River watershed (King County Department of Natural Resources, 1999). The site is located east of 156th Avenue SE and is bordered by SE 136th Street on the north and by 160th A venue SE on the east. Cover types on the site include a single-family residence, pasture, and forest. A Class 2 wetland has been identified in the northeast portion of the site. The site consists of two basins with most of the project area draining to the easterly basin. The easterly basin drains to a conveyance system along 160th Avenue SE. The westerly basin drains to a conveyance system along 156th Avenue SE. Both downstream drainage courses eventually discharge to an unclassified tributary of the Cedar River (King County Department of Parks, Planning, and Resources, 1990). ·I References Haozous Engineering, June 15, 2001. Evendell Plat -Preliminary Technical Information Report. Renton, Wash. King County Department of Natural Resources, 1998. King County Surface Water Design Manual. Seattle. King County Department of Natural Resources, 1997. Lawer Cedar River Basin and Nonpoint Pollution Action Plan. Seattle. King County Department of Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio. Seattle. U _ S. Department of Agriculture, Soil Conservation Service, 1973. Soil Survey of King County Area, Washington. Seattle. 6 Table 1. Summ-y of Surveyed Structures in Downstream System Reach ID Reach Pipe Dia. Manning's Length UpstrIE Dwnst IE Slope Type (IN) n (FT) (FT) (FT) (%) East Basin D-1 !0 X-Scction 0.035 48 408.54 407.59 199 D-111 X-Scction 0.035 58 409.57 408.54 1.78 D-112 X-Section 0.035 20 411.25 409.57 8.57 D-113 X-Section 0.035 12 411.86 411.25 5.28 D-114 X-Section 0.035 48 412.96 411.86 2.31 P-110 Circular 24 0.0!0 60 413.6 412.96 1.06 D-115 X-Section 0.035 3 414.27 413.6 · 25.24 D-116 X-Section 0.035 33 415.1 414.27 2.48 D-117 X-Section 0.035 24 415.34 415.1 I.OJ D-118 X-Section 0.035 25 417.07 415.34 7.01 D-119 X-Section 0.035 48 . 419.77 417.07 5.61 D-120 X-Section 0.035 79 420.05 419.77 0.35 P-111 Circular 18 0.013 29 419.3 420.05 -2.56 D-121 X-Section 0.035 6 421.94 419.3 45.68 D-122 X-Section 0.035 24 422.17 421.94 0.96 P-112 Circular 12 0.013 85 423.42 422.17 1.47 D-123 X-Section 0.035 43 424.16 423.42 1.73 D-124 X-Section 0.065 90 424.6 424.16 0.49 D-125 X-Section 0.065 107 426.13 424.6 1.43 D-126 X-Section 0.065 48 428.17 426.13 4.27 D-127 X-Section 0.035 79 429.74 428.17 1.99 D-128 X-Section 0.035 56 431.36 429.74 2.87 P-113 Circular 18 0.01 124 434.95 431.36 2.91 D-129 X-Section 0.035 12 434.81 434.95 -1.21 D-130 X-Section 0.035 61 436.28 434.81 2.40 D-131 X-Section 0.035 66 439.1 436.28 4.30 P-114 Circular 24 0.024 21 439.59 439.1 2.37 D-132 X-Section 0.035 10 440.26 439.59 7.02 P-115 Circular 12 0.013 45 441.31 439.59 3.78 D-133 X-Section 0.035 2 441.15 441.31 -7.30 D-133A X-Section 0.035 35 442.14 441.15 2.80 D-134 X-Section 0.035 50 443.4 442.14 2.53 D-135 X-Section 0 035 106 444.67 443.4 1.20 D-136 X-Section 0.035 54 445.89 444.67 2.25 P-116 Circular 18 0.024 28 446.34 445.89 1.62 D-137 X-Section 0.035 3 446.6 446.34 10.15 D-138 X-Section 0.035 88 448.4 446.6 2.04 D-139 X-Section 0.035 106 451.13 448.4 2.58 D-140 X-Section 0.035 55 452.3 451.13 2.15 P-117 Circular 12 0.013 18 452.9 452.3 3.39 D-141 X-Section 0.035 3 452.65 452.9 -9.42 D-142 X-Section 0.035 102 454.76 452.65 2.07 D-143 X-Section 0.035 160 459.46 454.76 2.93 D-144 X-Section 0.035 103 462.79 459.46 3.24 D-145 X-Section 0.035 100 466.72 462.79 3.92 .·I Table 1 ( continued) Reach ID Reach Pipe Dia. Manning's Length UpstrIE Dwnst IE Slope Type (IN) n (FT) (FT) (FT) (%) West Basin P-001 Circular 12 0.013 113 378.62 372.66 5.27 D-001 X-Section 0.035 3 379.22 378.62 20.00 D-002 X-Section 0.035 114 381.68 379.22 2.16 D-003 X-Section 0.035 153 388.9 381.68 4.72 D-004 X-Section 0.035 157 397.4 388.9 5.41 D-005 X-Section 0.035 2 396.77 397.4 -31.50 P-002 Circular 12 0.013 25 397.51 396.77 2.96- D-006 X-Section 0.035 3 398.49 397.51 32.67 D-007 X-Section 0.035 35 399.58 398.49 3.11 P-003 Circular 12 0.013 19 400.17 399.58 3.11 D-008 X-Section 0.035 2 400.4 400.17 11.50 D-009 X-Section 0.035 36 400.91 400.4 1.42 P-004 Circular 12 0.013 59 403.71 400.91 4.75 P-005 Circular 12 0.013 9 404.21 403.51 7.78 P-006 Circular 12 0.013 42 406.09 404.26 4.36 P-007 Circular 12 0.013 150 411.17 406.34 3.22 P-008 Circular 12 0.013 157 417.58 411.77 3.70 P-008A Circular 12 0.013 28 418.l 417.58 1.86 P-009 Circular 12 0.013 142 427.25 420.75 4.58 P-010 Circular 12 0.013 86 431.9 427.35 5.29 P-011 Circular 12 0.013 62 434.34 432 3.77 P-012 Circular 12 0.013 33 435.68 434.39 3.91 D-010 X-Section 0.035 3 436.07 435.68 13.00 D-011 X-Section 0.035 48 438.87 436.07 5.83 D-012 X-Section 0.035 53 442.78 438.87 7.38 P-013 Circular 12 0.013 19 444.46 442.78 8.84 D-014 X-Section 0.035 3 444.63 444.46 5.67 D-015 X-Section 0.035 43 446.52 444.63 4.40 P-014 Circular 12 0.013 23 447.67 446.52 5.00 D-016 X-Section 0.035 3 448.08 447.67 13.67 D-017 X-Section 0.035 57 450.3 448.08 3.89 P-015 Circular 12 0.013 22 451.33 450.3 4.68 D-018 X-Section 0.035 3 451.83 451.33 16.67 D-019 X-Section 0.035 52 454.6 451.83 5.33 P-016 Circular 12 0.013 34 457.55 454.6 8.68 D-020 X-Section 0.035 3 457.71 457.55 5.33 D-021 X-Section 0.035 107 465.05 457.71 6.86 Table 2. Summary of Existing Basin Cover Types by Subbasin Curve Number= Subbasin East Basin el e2 e3 e4 e5 e6 e7 Site -East Subtotal West Basin wl w2 w3 w4 w5 w6 w7 w8 Site - West Subtotal 81.0 85.0 Till-forest Till-pasture (AC) (AC) -5.8 6.0 5.2 -1.7 -- 4.0 1.8 14.9 3.5 1.8 - 8.9 2.2 35.6 20.2 -- -0.7 -- -- -- 0.8 - 1.6 - 3.8 4.9 0.4 1.4 6.6 7.0 98.0 86.0 98.0 Cover Type Wetland Till-grass Imperv (AC) (AC) (AC) 12.0 1.9 15.6 7.0 0.7 0.1 0.9 0.2 12.3 5.4 9.8 2.3 -- 0.4 -0.1 0.4 51.4 16.9 2.3 0.6 13.8 1.8 1.0 0.2 2.7 0.5 1.8 0.4 1.8 1.3 3.8 2.4 0.4 0.0 --0.1 -27.6 7.2 Total (AC) 19.7 33.9 2.4 I. I 23.5 30.4 1.8 11.6 124.5 2.9 16.3 1.2 3.2 2.2 3.8 7.8 9.1 1.9 48.4 -1 Table 4. Curve Numbers for Subbasins Subbasin Pervious Pervious Imperv CN (AC) (AC) East Basin el 85.7 17.8 1.9 c2 84.7 26.9 7.0 e3 85.3 2.3 0.1 e4 86.0 0.9 0.2 e5 84.8 18.1 5.4 e6 83.2 28.l 2.3 e7 81.0 1.8 - Site -East 81.8 I LI 0.5 West Basin wl 86.0 2.3 0.6 w2 86.0 14.5 1.8 w3 86.0 1.0 0.2 w4 86.0 2.7 0.5 w5 86.0 1.8 0.4 w6 84.5 2.5 1.3 w7 84.5 5.4 2.4 w8 83.4 9.0 0.0 Site - West 84.0 1.8 0.1 Table 5. Travel Path Distances and Slopes for Pervious Land Areas · Sh~gt; 'Fl<FW Delta Shallow Flow . JJ~l/(1, : Channel F/()W · · Delta Di,tdnc~ .. Subbasin Elev. Slope, Distance ·· Elev.; ····Slope Distance Elev. Slope ·· .. ··.~-.'' < :: /\:' .. (:, .. {F:Tl (FI) (FT/FT) (FI) (FJJ ·•·•,· . ·. (FT/FI) (FI) {FI) (FT/Fl) East Ba.sin el 300.0 5.0 0.017 1,484.0 20.0 0.013 950.0 I0.0 0.011 e2 300.0 5.0 0.017 922.0 15.0 0.016 1,824.0 18.0 0.010 e3 300.0 5.0 0.017 264.0 3.0 0.011 106.0 3.0 0 028 e4 300.0 5.0 0.017 200.0 4.0 0.020 e5 300.0 8.0 0.027 1,248.0 23.0 0.018 705.0 10.0 0.014 e6 300.0 3.0 O.OIO 1,777.0 35.0 0.020 e7 300.0 3.0 0.010 Site -Ea.st 300.0 3.0 O.OIO 876.0 13.0 0.015 West Ba.sin wl 2,610.0 70.0 0.027 w2 300.0 5.0 0.017 585.0 70.0 0.120 w3 300.0 32.0 0.107 272.0 13.0 0.048 w4 300.0 IO.O 0.033 292.0 22.0 0.075 w5 300.0 30.0 O.IOO 322.0 22.0 0.068 w6 300.0 2.0 0.007 613.0 40.0 0.065 w7 300.0 20.0 0.067 655.0 40.0 0.061 w8 300.0 20.0 0.067 1,020.0 70.0 0.069 Site - West 210.0 10.0 0.048 :.:.. Table 6. Peak Flow Rates at Selected Locations. Storm Return Period Location 2-Year JO-year 25-Year SO-Year JOO-Year (CFS) (CFS) (CFS) (CFS) (CFS) East Basin P-1 JO 12.0 24.5 31.6 35.3 38.9 P-111 12.1 24.9 32.0 35.6 39.4 P-112 9.9 20.0 25.5 28.3 31.2 P-113 10.2 20.3 25.9 28.7 31.6 P-114 10.2 20.4 25.9 28.8 31.7 P-115 7.4 15.2 19.4 21.6 23.8 P-116 7.3 14.9 19.l 21.2 23.4 West Basin P-001 6.8 13.7 17.5 19.4 21.2 P-002 6.2 12.2 15.4 17.0 18.6 P-006 4.8 9.6 12.2 13.5 14.7 P-008A 4.1 8.4 10.8 11.9 13.l P-009 3.8 7.7 9.8 10.9 11.9 P-013 3.2 6.7 8.5 9.4 10.4 P-015 3.0 6.2 8.0 8.8 9.7 P-016 2.8 5.7 7.3 8.1 8.9 Note: Flow rates are those predicted by Stormshed nsing the SBUH method. ., SOURCE: USGS 7.5 x 15 Minute Series -Renton, Washington SCALE: 1 :25 000 TITT.E Figure 1. Vicinity Map PAGE "'"' 1-5 01/03/01 Appendix A. Stormshed Model Input/Output Design Storm Rainfall Amounts Return Rainfall Period Amount (YRS) (IN) 2 2.00 10 3.00 25 3.50 50 3.75 100 4.00 ' .·\ Appendix A.I. Subbasin Summary -East Basin Drainage Area: e-001 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervious 17.8000 ac 85.70 Impervious 1.9000 ac 98.00 Total 19.7000 ac Pervious CN Data: Sub basin e-001 Perv Impervious CN Data: Subbasin e 1 Imperv Pervious TC Data: Flow type: Description: Sheet el sheet Shallow e 1 shallow Channel e 1 channel Impervious TC Data: Flow type: Description: Fixed None Entered 85.70 98.00 Loss Method: SCS CN Number SCS Abs: Intv: 0.20 10.00 min TC 0.98 hrs 0.17 hrs 17.8000 ac 1.9000 ac Length: Slope: 300.00ft 1.70% 1484.00 ft 1.50% 950.00ft 1.10"/o Length: Slope: 0.00 ft 0.00% Coeff: Travel Time 0.1500 31.85min 11.0000 18.36 min 17.0000 8.88 min Coeff: Travel Time 10.0000 10.00 min Drainage Area: e--002 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 26.9000 ac Impervious 7.0000 ac Total 33.9000 ac Pervious CN Data: Subbasin e-002 Perv Impervious CN Data: Subbasin el Imperv Pervious TC Data: Flow type: Description: Sheet e2 sheet Shallow e2 shallow Channel e2 channel Impervious TC Data: Flow type: Description: Fixed None Entered CN 84.70 98.00 84.70 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC LOI hrs 0.17 hrs 26.9000 ac 7.0000 ac Length: Slope: 300.00 ft 1.70% 922.00 ft 1.60% 1824.00 ft 1.00% Length: Slope: 0.00 ft 0.00% Coeff: Travel Time 0.1500 31.85 min 11.0000 11.04 min 17.0000 17.88min Coeff: Travel Time 10.0000 10.00 min .\ Drainage Area: e-003 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 2.3000 ac 85.30 0.60 hrs Impervious 0.1000 ac 98.00 0.17hrs Total 2.4000 ac Pervious CN Data: Subbasin e-003 Perv 85.30 2.3000 ac Impervious CN Data: Subbasin e3 Imperv 98.00 0.1000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet e3 sheet 300.00 fl 1.70% 0.1500 31.85 min Shallow e3 shallow 264.00 fl 1.10% I 1.0000 3.81 min Channel e3 channel 106.00 fl 2.80% 17.0000 0.62 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 fl 0.00"/o 10.0000 10.00min Drainage Area: e--004 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00min Area CN TC Pervious 0.9000 ac 86.00 0.55 hrs Impervious 0.2000 ac 98.00 0.17hrs Total 1.1000 ac Pervious CN Data: Subbasin e-004 Perv 86.00 0.9000 ac Impervious CN Data: Subbasin e4 Imperv 98.00 0.2000ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet e4 sheet 300.00 ft 1.70% 0.1500 31.85 min Channel e4 channel 200.00 ft 2.00% 17.0000 1.39 min Impervious TC Data: Flow type: Description: Length: Slope: Coetf: Travel Time Fixed None Entered 0 00 ft 0.00% 10.0000 10.00 min ., Drainage Area: e-005 HydMethod: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 18.1000 ac Impervious 5.4000 ac Total 23.5000 ac Pervious CN Data: Subbasin e-005 Perv Impervious CN Data: Subbasin e5 Imperv Pervious TC Data: Flow type: Description: Sheet e5 sheet Shallow e5 shallow Sheet e5 channel Impervious TC Data: Flow type: Description: Fixed None Entered CN 84.80 98.00 84.80 98.00 Loss Method: SCS CN Number SCS Abs 0.20 Intv: 10.00 min TC 1.81 hrs 0.17 hrs 18.1000 ac 5.4000 ac Length: Slope: 300.00 ft 2.70% 1248.00 ft 1.80%, 705.00 ft 140% Length: Slope: 0.00 ft 0.00% Coeff Travel Time 0.1500 26.47 min 11.0000 14 09 min 0.1500 68.19 min Coeff: Travel Time 10.0000 10.00 min Drainage Area: e-006 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervious 28.1000 ac 83.20 Impervious 2.3000 ac 98.00 Total 30.4000 ac Pervious CN Data: Subbasin e-006 Perv Impervious CN Data: Subbasin e5 Imperv Pervious TC Data: 83.20 98.00 Flow type: Description: Length: Sheet e6 sheet Shallow e6 shallow Impervious TC Data: Flow type: Description: Fixed None Entered Loss Method: SCS CN Number SCS Abs: 0.20 lntv: 10 00 min TC 1.35 hrs 0.17 hrs 28.1000 ac 2.3000 ac Slope: Coeff: Travel Time 300.00 ft 100% 0.1500 39.38 min 1777.00 ft 2.00% 5.0000 41.88 min Length: Slope: Coeff: Travel Time 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: e-007 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious I. 8000 ac Impervious 0.0000 ac Total I. 8000 ac Pervious CN Data: Subbasin e-007 Perv Pervious TC Data: Flow type: Description: Sheet e 7 sheet CN 81.00 98.00 81.00 Loss Method: SCS CN Number SCS Abs: Intv: TC 1.44 hrs 0.00 hrs 1.8000 ac 0.20 10.00 min Length: Slope: 300.00 ft 1.00% Coeff: 0.4000 Travel Time 86.31 min Drainage Area: ex_ east Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervious 11.1000 ac 81.80 Impervious 0.5000 ac 98.00 Total 11.6000 ac Pervious CN Data: Subbasin ex east Perv 81.80 Impervious CN Data: Subbasin ex_ east Imperv 98.00 Pervious TC Data: Flow type: Description: Sheet ex east sheet Shallow ex east shallow Impervious TC Data: Flow type: Description: Fixed None Entered Loss Method: · SCS CN Number SCS Abs: lntv: TC 2.10 hrs 0.17 hrs 11.1000 ac 0.5000 ac Length: 300.00 ft 876.00 ft Length: 0.00 ft 0.20 10 00 min Slope: Coeff: 1.00% 0.4000 1.50% 3.0000 Slope: Coeff: 0.00% 10.0000 Travel Time 86.31 min 39.74 min Travel Time 10.00 min ' -, Appendix A.2. Subbasin Summary-West Basin Drainage Area; w-001 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 2.3000 ac Impervious 0.6000 ac Total 2.9000 ac Pervious CN Data: Subbasin wl Perv Impervious CN Data: Subbasin wl Pervious TC Data: Flow type: Description: Time Channel wl Impervious TC Data: Flow type: Description: Time Fixed wl Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min CN TC 86.00 0.26 hrs 98.00 0.17 hrs 86.00 2.3000 ac 98.00 0.6000 ac Length: Slope: Coeff Travel 2610.00 ft 2.70% 17.0000 15.57 min Length: Slope: Coeff Travel 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: w-002 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 14.5000 ac 86.00 0.57 hrs Impervious 1.8000 ac 98.00 0.17hrs Total 16.3000 ac Pervious CN Data: Subbasin w2 PeIV 86.00 14.5000 ac Impervious CN Data: Subbasin w2 Imperv 98.00 1.8000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet None Entered 300.00 ft 1. 70"/o 0.1500 31.85 min Shallow None Entered 585.00 ft 12.00% 11.0000 2.56 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min .,, Drainage Area: w-003 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 1.0000 ac 86.00 0.27 hrs Impervious 0.2000 ac 98.00 0.17hrs Total 1.2000 ac Pervious CN Data: Subbasin w3 Perv 86.00 1.0000 ac Impervious CN Data: Subbasin w3 Imperv 98.00 0.2000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w3 sheet 300.00 ft 10.70"/o 0.1500 15.26 min Channel w3 channel 272.00 ft 4.80% 17.0000 1.22 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: w-004 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 2.7000 ac 86.00 0.43 hrs Impervious 0.5000 ac 98.00 0.17 hrs Total 3.2000 ac Pervious CN Data: Subbasin w4 Perv 86.00 2.7000 ac Impervious CN Data: Subbasinw4 98.00 0.5000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w4 sheet 300.00 ft 3.30"/o 0.1500 24.43 min Shallow w4 shallow 292.00 ft 7.50% 11.0000 1.62 min Impervious TC Data: Flow type: Description: Length: Time Slope: Coeff: Travel Fixed None Entered 0 00 ft 0.00% 10.0000 10.00 min Drainage Area: w-005 Hyd Method: SBUHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 1.8000 ac 86.00 0.29 hrs Impervious 0.4000 ac 98.00 0.17hrs Total 2.2000 ac Pervious CN Data: Subbasin w5 Perv 86.00 1.8000 ac Impervious CN Data: Subbasin w5 98.00 0.4000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w5 sheet 300.00 ft 10.00% 0.1500 15.68 min Shallow wS shallow 322.00 ft 6.80% 11.0000 1.87 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min Drainage Area; w-006 Hyd Method: SBlJHHyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 2.5000 ac 84.50 0.82 hrs Impervious 1.3000 ac 98.00 0.17hrs Total 3.8000 ac Pervious CN Data: Subbasin w6 Perv 84.50 2.5000 ac Impervious CN Data: Subbasin w6 98.00 1.3000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet w6 sheet 300.00 ft 0.700/o 0.1500 45.42 min Shallow w6 shallow 613.00 ft 6.50% 11.0000 3.64min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 10.0000 10.00 min Drainage Area: w-008 Hyd Method SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 9.0000 ac Impervious 0 0000 ac Total 9.0000 ac Pervious CN Data: Subbasin w8 Perv Pervious TC Data: Flow type: Description: Time Sheet w8 sheet Shallow w8 shallow Impervious TC Data: Flow type: Description: Time Fixed None Entered CN 83.40 0.00 83.40 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 0.79 hrs O.I7hrs 9.0000 ac Length: Slope: 300.00 ft 6.70% 1020.00 ft 6.90% Length: Slope: 0.00 ft 0.00% Coeff: Travel 0.4000 40.33 min 9.0000 7.19min Coeff: Travel 10.0000 10.00 min ' ., Drainage Area: ex_west Hyd Method SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 1.8000 ac Impervious 0.1000 ac Total 1.9000 ac Pervious CN Data: Subbasin ex west Perv Impervious CN Data: Subbasin ex west Imperv Pervious TC Data: Flow type: Description: Time Sheet ex west sheet Impervious TC Data: Flow type: Description: Time Fixed wl CN 84.00 98.00 84.00 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 0.38 hrs 0.17 hrs 1.8000 ac 0.1000 ac Length: Slope: Coeff: Travel 210.00 ft 4.80% 0.2400 23.02 min Length: Slope: Coeff: Travel 0 00 ft 0.00% 10.0000 10.00 min .. ; Appendix B. Hydrograph Routing Table B.1. Hydrograph Routing -East Basin -2-Year Storm ROUTEHYD D THRU [Existing East] USING TYPE1A AND [2 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin I Hyd ac cfs cfs ratio ft ft/s ft/s ------------ D-Dum2 19.7 2.1303 122.33 0.02 0.3312 X-Sect 3.0688 ----e-001 D-Dum1 53.6 6.625 122.33 0.05 0.5728 X-Seci 4.4532 -----e-002 D-145 53.6 6.5953 121.12 0.05 0.57 44 X-Sect 4.4169 ---- D-144 53.6 6.5642 117.92 0.06 0.6659 X-Sect 4.3432 ----- D-143 53.6 6.5478 122.41 0.05 0.6381 X-Sect 4.0213 ---- D-142 53.6 6.5467 82.3869 0.08 0.6881 X-Sect 3.5759 ---- D-141 53.6 6.5465 10.3949 0.63 1.6141 X-Sect 1.1146 -- P-117 65.2 7.0246 6.5804 1.07 0.9037 12" Diam 9.4073 8.3784 ex_east D-140 65.2 7.0224 124.5 0.06 0.4782 X-Sect 3.1305 --- D-139 65.2 7.018 117.81 0.06 0.4685 X-Sect 3.4675 ----- D-138 65.2 7.013 94.8108 0.07 0.6314 X-Sect 3.4413 ---- D-137 67.6 7.2807 279 0.03 0.4113 X-Sect 5.3323 ----e-003 P-116 67.6 7.2787 7.2535 1 1.2342 18" Diam 4.6787 4.1046 D-136 67.6 7.2745 61.7242 0.12 0.6832 X-Sect 3.5858 ---- D-135 67.6 7.2645 66.6905 0.11 0. 7836 X-Sect 2.9393 ---- D-134 67.6 7.2596 70.9939 0.1 0.5719 X-Sect 3.6244 -- D-133A 67.6 7.2557 93.7984 0.08 0.6719 X-Sect 3.6325 --- D-133 67.6 7.2549 26.6671 0.27 1.4156 X-Sect 1.1841 -- P-115 68.7 7.4254 6.9473 1.07 0.9067 12" Diam 9.9203 8.8456 e-004 D-132 68.7 7.4237 226.87 0.03 0.5902 X-Sect 5.7063 --- P-114 92.2 10.2247 18.9199 0.54 1.0474 24" Diam 6.1392 6.0224 e-005 D-131 92.2 10.2216 338.51 0.03 0.5631 X-Sect 4.9185 --- D-130 92.2 10.2183 33.2703 0.31 0.8395 X-Sect 4.3224- D-129 92.2 10.2164 8.6723 1.18 -1 X-Sect 1.178 ---- P-113 92.2 10.212 23.5738 0.43 0.6902 18" Diam 12.8615 13.34 D-128 92.2 10.2081 266.41 0.04 0.6392 X-Sect 4.3565 -- D-127 92.2 10.1973 1354.11 0.01 0.6263 X-Sect 2.0863 ---- D-126 92.2 10.1853 491.48 0.02 0.3323 X-Sect 1.4977 ----- D-125 92.2 10.132 3470.27 0 0.3539 X-Sect 0.8642 ---- D-124 92.2 9.9841 549.84 0.02 0.2991 X-Sect 0.5983 ---- D-123 92.2 9.9643 3827.85 0 0.4105 X-Sect 1.946 -- P-112 92.2 9.9216 4.3371 2.29 -1 12" Diam 2.2876 5.5221 D-122 92.2 9.9128 50.2681 0.2 0.904 X-Sect 2.771 ---- D-121 122.6 12.0698 594.02 0.02 0.2893 X-Sect 10 .2968 -----e-006 P-111 122.6 12.0648 15.3148 0.79 1.0036 18" Diam 9.6013 8.6664 D-120 122.6 12.0245 18.2879 0.66 1 .4658 X-Sect 2.1936 ---- D-119 122.6 12.0107 17.5281 0.69 0.6067 X-Sect 4.6997 ---- D-118 122.6 12.0027 179.94 0.07 0.4436 X-Sect 5.2531 --- D-117 122.6 11.9926 61.1492 0.2 1.0638 X-Sect 2.9017 ---- D-116 122.6 11.9823 27.9865 0.43 1.096 X-Sect 4.2499 -- D-115 122.6 11.9814 78.2241 0.15 1.2007 X-Sect 4.2155 ---- P-110 122.6 11.972 30.6525 0.39 0.868 24" Diam 9.156 9.757 D-114 122.6 11.9572 47.75 0.25 1.1715 X-Sect 4.2164 ---- D-113 124.4 12.0112 319.76 0.04 0.6751 X-Sect 5.8978 -----e-007 D-112 124.4 12.0055 1134.16 0.01 0.5548 X-Sect 5.7484 -- D-111 124.4 11.9853 413.21 0.03 0.7639 X-Sect 3.7479 ---- D-110 124.4 11.9689 241.55 0.05 0.698 X-Sect 3.9096 ••••. Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl fl fl fl fl N-110 408.288 N-111 N-110 409.238 -na----na----na--409.238 411.92 N-112 N-111 409.9703 -na-· --na--na--409.9703 414.13 N-113 N-112 411.6608 --na----na----na--411.6607 415.64 N-114 N-113 412.5349 --na---na----na--412.5349 415.67 N-115 N-114 414.1314 --na----na---na--414.18 414.08 N-116 N-115 415.5033 -na---na---na--415.5033 416.5 N-117 N-116 415.5562 --na--na---na-415.5562 416.39 N-118 N-117 416.3861 -na--na--na-416.3861 416.39 N-119 N-118 416.626 -na--na--na--416.71 416.61 N-120 N-119 418.44 --na--na---na--418.24 418.14 N-121 N-120 420.9399 --na---na---na--420.43 420.33 N-122 N-121 421 .5157 -na---na---na--421.5157 422.69 N-123 N-122 422.9861 -na---na----na-422.9861 423.31 N-124 N-123 425.626 -na--na---na--423.41 423.31 N-125 N-124 423.64 -na--na---na--423.64 424.05 N-126 N-125 433.8967 -na---na----na--424.9 424.8 N-127 N-126 425.6399 --na---na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427.6098 --na--na--na--427.6097 428.27 N-130 N-129 429.6497 --na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.4499 -na--na--na--432.45 432.79 N-133 N-132 437 .2623 --na---na--na-436.5 436.4 N-134 N-133 436.5119 --na-· -na---na-436.03 435.93 N-135 N-134 437.4999 -na---na---na-437.57 437.47 N-136 N-135 440.3899 -na-· -na--na--440.25 440.15 N-137 N-136 441.418 --na--na---na-441.418 442.1 N-137A N-137 442.088 -na---na---na--441.99 441.89 N-138 N-137A 445.5185 --na---na---na-442.9 442.8 N-139 N-138 442.9019 -na--na--na-442.9 442.8 N-140 N-139 443.8899 --na-· -na---na-443.14 443.04 N-141 N-140 444.3999 -na-· -na---na-444.3999 444.84 N-142 N-141 445.6699 -na--na--na--445.6699 446.11 N-143 N-142 446.8898 --na-· -na---na-446.8898 447.71 N-144 N-143 448.3436 -na-· --na---na-448.2 448.1 N-145 N-144 448.4599 -na-· --na--na--447.84 447.74 N-146 N-145 449.6399 --na--na--na--449.6399 449.84 N-147 N-146 452.3699 -na--na--na--452.3698 452.71 N-148 N-147 453.5398 -na--na---na-453.5398 453.89 N-149 N-148 456.7368 -na--na--na-454.3 454.2 N-150 N-149 454.303 -na--na--na-454.3029 454.65 N-151 N-150 456.4129 --na-· -na--na--455.87 455.77 N-152 N-151 460.5699 --na--na--na-460.56 460.46 N-153 N-152 463.89 ··03·· -na--na--463.89 464.17 N-154 N-153 467.8199 -na--na---na-467.44 467.34 , _.. Table B.2. Hydrograph Routing -East Basin -10-Year Storm ROlJTEHYD [) THRU [Existing East] USING TYPE1A AND [10 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin I Hyd ac cfs cfs ratio ft ft/s ft/s ------------ O-Dum2 19.7 4.4884 122.33 0.04 0.4719 X-Sect 3.935 ----e-001 D-Dum1 53.6 13.1058 122.33 0.11 0.81 X-Sect 5.5304 --e-002 D-145 53.6 13.1051 121.12 0.11 0.8142 X-Sect 5.4927 ---- 0-144 53.6 13.1036 117.92 0.11 0.9649 X-Sect 5.2679 ---- 0-143 53.6 13.1 122.41 0.11 0.9032 X-Sect 4.856 ---- 0-142 53.6 13.0953 82.3869 0.16 0.9821 X-Sect 4.3102 --- 0-141 53.6 13.0948 10.3949 1.26 -1 X-Sect 1.2597 ----- P-117 65.2 14.3238 6.5804 2.18 -1 12" Diam 2.1767 8.3784 ex_east 0-140 65.2 14.3181 124.5 0.12 0.6926 X-Sect 3.9913 -- D-139 65.2 14.3076 117.81 0.12 0.6891 X-Sect 4.3262- 0-138 65.2 14.2973 94.8108 0.15 0.9065 X-Sect 4.2086 ----- D-137 67.6 14.8971 279 0.05 0.5622 X-Sect 6.5644 ---e-003 P-116 67.6 14.8875 7.2535 2.05 -1 18" Diam 2.0525 4.1046 D-136 67.6 14.8791 61.7242 0.24 0.9641 X-Sect 4.5155 -- D-135 67.6 14.86 66.6905 0.22 1.1209 X-Sect 3.6062 ---- D-134 67.6 14.8509 70.9939 0.21 0.8189 X-Sect 4.472- D-133A 67.6 14.8437 93.7984 0.16 0.899 X-Sect 4.4767 -- D-133 67.6 14.8424 26.6671 0.56 1.9795 X-Sect 1.4503- P-115 68.7 15.1643 6.9473 2.18 -1 12" Diam 2.1828 8.8456 e-004 D-132 68.7 15.1617 226.87 0.07 0.8315 X-Sect 7.0313- P-114 92.2 20.3817 18.9199 1.08 -1 24" Diam 1.0773 6.0224 e-005 D-131 92.2 20.3728 338.51 0.06 0.8183 X-Sect 6.0985- 0-130 92.2 20.3642 33.2703 0.61 1 .2093 X-Sect 5.2653- D-129 92.2 20.3511 8.6723 2.35 -1 X-Sect 2.3467-- P-113 92.2 20.3415 23.5738 0.86 1.0749 18" Diam 15.0091 13.34 D-128 92.2 20.3328 266.41 0.08 0.9398 X-Sect 5.4109 ---- 0-127 92.2 20.3088 1354.11 0.01 0.7502 X-Sect 2.4283 -- D-126 92.2 20.2866 491.48 0.04 0.428 X-Sect 1.9106 ---- 0-125 92.2 20.1873 3470.27 0.01 0.4582 X-Sect 1.0267 ---- D-124 92.2 20.03 549.84 0.04 0.4223 X-Sect 0.7679- D-123 92.2 19.9985 3827.85 0.01 0.5331 X-Sect 2.3162- P-112 92.2 19.9587 4.3371 4.6 -1 12" Diam 4.6019 5.5221 0-122 92.2 19.9456 50.2681 0.4 1.2487 X-Sect 3.3192 ---- D-121 122.6 24.93 594.02 0.04 0.4161 X-Sect 13.223-e-006 P-111 122.6 24.8832 15.3148 1.62 -1 18" Diam 1.6248 8.6664 D-120 122.6 24.6416 18.2879 1.35 -1 X-Sect 1.3474- 0-119 122.6 24.5438 17.5281 1.4 -1 X-Sect 1.4002 -- 0-118 122.6 24.5308 179.94 0.14 0.6339 X-Sect 6.562- 0-117 122.6 24.5144 61.1492 0.4 1.4223 X-Sect 3.6544- 0-116 122.6 24.4971 27.9865 0.88 1.4271 X-Sect 5.1474 - 0-115 122.6 24.4955 78.2241 0.31 1.6574 X-Sect 5.1522- P-110 122.6 24.4801 30.6525 0.8 1.3515 24" Diam 10.8367 9.757 0-114 122.6 24.4557 47.75 0.51 1.5399 X-Sect 5.2816 -- 0-113 124.4 24.6393 319.76 0.08 1.0057 X-Sect 7.2971 -e-007 0-112 124.4 24.6301 1134.16 0.02 0. 7 42 X-Sect 7.4221 - 0-111 124.4 24.5979 413.21 0.06 1.1252 X-Sect 4.6448 -- ., D-110 124.4 24.5719 241.55 0.1 1.0455 X-Sect 4.8977 ----- Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node It It It It It It N-110 408.6355 N-111 N-110 409.5854 --na----na---na--409.5854 411.92 N-112 N-111 410.6952 --na----na---na--410.6952 414.13 N-113 N-112 412.3751 --na----na---na-412.3751 415.64 N-114 N-113 412.985 --na----na---na-412.985 415.67 N-115 N-114 414.5504 -na---na--na-414.18 414.08 N-116 N-115 417.346 --na---na--na-416.6 416.5 N-117 N-116 416.6529 --na--na---na-416.49 416.39 N-118 N-117 417.3199 --na--na--na-416.49 416.39 N-119 N-118 416.7623 -na---na--na--416.71 416.61 N-120 N-119 418.4399 --na---na--na-418.24 418.14 N-121 N-120 420.9399 --na---na---na-420.43 420.33 N-122 N-121 421.3322 --na--na--na-421.3322 422.69 N-123 N-122 427.5867 -na---na--na-423.41 423.31 N-124 N-123 426.0499 --na--na---na--423.41 423.31 N-125 N-124 423.6399 -na---na---na--423.64 424.05 N-126 N-125 465.1461 -na---na---na--424.9 424.8 N-127 N-126 425.6399 -na--na---na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na--426.0798 426.52 N-129 N-128 427.6098 -na--na---na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.4499 -na--na--na-432.45 432.79 N-133 N-132 441.2068 -na---na---na--436.5 436.4 N-134 N-133 436.5119 --na--na----na-436.03 435.93 N-135 N-134 437.4999 -na--na--na-437.57 437.47 N-136 N-135 440.3899 -na--na--na-440.25 440.15 N-137 N-136 442.9103 -na---na----na-442.2 442.1 N-137A N-137 442.87 -na---na----na-441.99 441.89 N-138 N-137A 458.8658 -na---na---na-442.9 442.8 N-139 N-138 443.1294 -na--na--na-442.9 442.8 N-140 N-139 443.89 -na---na---na--443.14 443.04 N-141 N-140 444.3999 -na--na---na-444.3999 444.84 N-142 N-141 445.7908 -na---na----na-445.7908 446.11 N-143 N-142 447.0108 -na---na----na-447.0107 447.71 N-144 N-143 451.3791 -na---na---na--448.2 448.1 N-145 N-144 448.46 -na---na---na-447.84 447.74 N-146 N-145 449.6399 -na--na--na-449.6399 449.84 N-147 N-146 452.3698 -na--na--na--452.3698 452.71 N-148 N-147 453.5397 -na---na--na-453.5397 453.89 N-149 N-148 464.129 -na--na--na-454.3 454.2 N-150 N-149 454.3029 -na--na--na-454.3029 454.65 N-151 N-150 456.4128 --na---na---na-455.87 455.77 N-152 N-151 460.5699 -na--na---na-460.56 460.46 N-153 N-152 463.8899 -na---na---na-463.89 464.17 N-154 N-153 467.8199 -na---na---na-467.44 467.34 ·I Table B.3. Hydrograph Routing -East Basin -25-Year Storm ROUTEHYD O THRU [Existing East] USING TYPE1A AND (25 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ---------- D-Dum2 19.7 5.7736 122.33 0.05 0.5347 X-Sect 4.2649 ----e-001 D-Dum1 53.6 16.6641 122.33 0.14 0.9204 X-Sect 5.9522 --e-002 D-145 53.6 16.6623 121.12 0.14 0.9253 X-Sect 5.911 ----- D-144 53.6 16.6597 117.92 0.14 1.095 X-Sect 5.6189 --- D-143 53.6 16.6543 122.41 0.14 1.0158 X-Sect 5.1748 --- D-142 53.6 16.6481 82.3869 0.2 1.1029 X-Sect 4.6242 ---- D-141 53.6 16.6444 10.3949 1.6 -1 X-Sect 1.6012 -- P-117 65.2 18.3188 6.5804 2.78 -1 12" Diam 2.7838 8.3784 ex_east D-140 65.2 18.3118 124.5 0.15 0.7894 X-Sect 4.3271 --- D-139 65.2 18.2992 117.81 0.16 0. 786 X-Sect 4.6556- D-138 65.2 18.2868 94.8108 0.19 1.0247 X-Sect 4.5015 --- D-137 67.6 19.0686 279 0.07 0.6269 X-Sect 7.0354 -----e-003 P-116 67.6 19.0592 7.2535 2.63 -1 18" Diam 2.6276 4.1046 D-136 67.6 19.0493 61.7242 0.31 1.0913 X-Sect 4.8719 - D-135 67.6 19.0273 66.6905 0.29 1.2672 X-Sect 3.86 --- D-134 67.6 19.0167 70.9939 0.27 0.926 X-Sect 4.7959 -- D-133A 67.6 19.0082 93.7984 0.2 0.9908 X-Sect 4.8691 -- D-133 67.6 19.0069 26.6671 0.71 2.2289 X-Sect 1.5584 -- P-115 68.7 19.4194 6.9473 2.8 -1 12" Diam 2.7952 8.8456 e-004 D-132 68.7 19.4163 226.87 0.09 0.9372 X-Sect 7.5367-- P-114 92.2 25.943 18.9199 1.37 -1 24" Diam 1.3712 6.0224 e-005 D-131 92.2 25.9323 338.51 0.08 0.9321 X-Sect 6.5545- D-130 92.2 25.9219 33.2703 0.78 1.3721 X-Sect 5.6512- D-129 92.2 25.9106 8.6723 2.99 -1 X-Sect 2.9877 -- P-113 92.2 25.8992 23.5738 1.1 -1 18" Diam 1.0986 13.34 D-128 92.2 25.8888 266.41 0.1 1.076 X-Sect 5.818 ---- D-127 92.2 25.8608 1354.11 0.02 0.8003 X-Sect 2.5676- D-126 92.2 25.8358 491.48 0.05 0.4713 X-Sect 2.076 --- D-125 92.2 25.7224 3470.27 0.01 0.5018 X-Sect 1.0908 ---- D-124 92.2 25.5489 549.84 0.05 0.478 X-Sect 0.836- D-123 92.2 25.5134 3827.85 0.01 0.584 X-Sect 2.4616 - P-112 92.2 25.4763 4.3371 5.87 -1 12" Diam 5.8741 5.5221 D-122 92.2 25.4617 50.2681 0.51 1.3879 X-Sect 3.5601 -- D-121 122.6 32.0486 594.02 0.05 0.4735 X-Sect 14.376 --e-006 P-111 122.6 32.0049 15.3148 2.09 -1 18" Diam 2.0898 8.6664 D-120 122.6 31.7866 18.2879 1.74 -1 X-Sect 1.7381 - D-119 122.6 31.6961 17.5281 1.81 -1 X-Sect 1.8083 -- D-118 122.6 31.6812 179.94 0.18 0.7203 X-Sect 7.0837- D-117 122.6 31.6627 61.1492 0.52 1.5908 X-Sect 3.9591 - D-116 122.6 31.6418 27.9865 1.13 -1 X-Sect 1.1306- D-115 122.6 31.64 78.2241 0.4 1.866 X-Sect 5.5186 - P-110 122.6 31.6228 30.6525 1.03 1.7027 24" Diam 11.096 9.757 D-114 122.6 31.5955 47.75 0.66 1.7176 X-Sect 5.6991 - D-113 124.4 31.8576 319.76 0.1 1.1584 X-Sect 7.8462-e-007 D-112 124.4 31.8471 1134.16 0.03 0.8307 X-Sect 8.1092 -- D-111 124.4 31.8116 413.21 0.08 1.2906 X-Sect 4.9987 ---- D-110 124.4 31.7828 241.55 0.13 1 .207 X-Sect 5.2894 .•••• Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl fl fl fl fl N-110 408.797 N-111 N-110 409.747 --na----na---na--409.747 411.92 N-112 N-111 410.8606 --na----na---na-410.8606 414.13 N-113 N-112 412.5405 --na--na----na--412.5405 415.64 N-114 N-113 413.1504 --na----na---na--413.1505 415.67 N-115 N-114 414.8065 --na--na--na-414.18 414.08 .N-116 N-115 418.962 --na---na--na--416.6 416.5 N-117 N-116 416.6529 -na---na--na-416.49 416.39 N-118 N-117 417.3199 -na--na----na-416.49 416.39 N-119 N-118 416.9307 -na---na---na-416.71 416.61 N-120 N-119 418.4399 --na---na----na--418.24 418.14 N-121 N-120 420.9399 -na---na----na--420.43 420.33 N-122 N-121 421.5229 --na---na---na-421.5229 422.69 N-123 N-122 431.8698 --na---na---na--423.41 423.31 N-124 N-123 426.0499 --na--na---na-423.41 423.31 N-125 N-124 423.64 --na----na---na-423.64 424.05 N-126 N-125 491.2671 --na----na---na-424.9 424.8 N-127 N-126 425.6399 -na---na--na--425.6399 426.02 N-128 N-127 426.0798 -na---na--na-426.0798 426.52 N-129 N-128 427.6098 -na--na--na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.45 -na--na---na-432.45 432.79 N-133 N-132 437.2202 -na---na---na-436.5 436.4 N-134 N-133 436.5119 -na---na---na-436.03 435.93 N-135 N-134 437 .85 --na--na--na-437.57 437.47 N-136 N-135 440.39 --na----na--na-440.25 440.15 N-137 N-136 444.033 --na----na----na-442.2 442.1 N-137A N-137 442.8699 --na----na---na--441.99 441.89 N-138 N-137A 469.665 --na---na----na-442.9 442.8 N-139 N-138 443.3789 --na---na---na-442.9 442.8 N-140 N-139 443.89 --na----na---na--443.14 443.04 N-141 N-140 444.3999 --na---na--na--444.3999 444.84 N-142 N-141 445.9371 --na----na---na-445.9371 446.11 N-143 N-142 447.157 -na---na---na-447.157 447.71 N-144 N-143 453.928 -na----na---na--448.2 448.1 N-145 N-144 448.46 -na---na---na-447.84 447.74 N-146 N-145 449.6399 -na---na---na-449.6399 449.84 N-147 N-146 452.3699 -na--na--na-452.3699 452.71 N-148 N-147 453.5398 -na--na--na-453.5398 453.89 N-149 N-148 470.8597 -na--na--na-454.3 454.2 N-150 N-149 454.3029 --na--na---na--454.3029 454.65 N-151 N-150 456.4129 -na--na--na--455.87 455.77 N-152 N-151 460.5699 --na----na---na--460.56 460.46 N-153 N-152 463.8981 -na----na--na--463.8981 464.17 N-154 N-153 467 .828 --na----na---na--467.44 467.34 ' ·• Table B.4. Hydrograph Routing -East Basin -50-Year Stonn ROUTEHYD O THRU [Existing East] USING TYPE1A AND [50 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ---------- D-Dum2 19.7 6.4328 122.33 0.05 0.5644 X-Secl 4.4125 -----e-001 D-Dum1 53.6 18.4875 122.33 0.15 0.9737 X-Sect 6.1401 -----e-002 D-145 53.6 18.4851 121.12 0.15 0.9789 X-Secl 6.0973 ---- D-144 53.6 18.482 117.92 0.16 1.1561 X-Sect 5.7757 ---- D-143 53.6 18.4757 122.41 0.15 1.0682 X-Sect 5.3178 --- D-142 53.6 18.4689 82.3869 0.22 1.16 X-Sect 4.7688 ---- D-141 53.6 18.4652 10.3949 1.78 -1 X-Secl 1.7764 - P-117 65.2 20.3744 6.5804 3.1 -1 12" Diam 3.0962 8.3784 ex_east D-140 65.2 20.3667 124.5 0.16 0.8355 X-Secl 4.4786 --- D-139 65.2 20.3531 117.81 0.17 0.8317 X-Sect 4.8035 ---- D-138 65.2 20.3398 94.8108 0.21 1.0799 X-Secl 4.6329 ---- D-137 67.6 21.2149 279 0.08 0.6572 X-Sect 7.2468 ---e-003 P-116 67.6 21.2056 7.2535 2.92 -1 18" Diam 2.9235 4.1046 D-136 67.6 21.1949 61.7242 0.34 1.152 X-Sect 5.0314 - D-135 67.6 21.1716 66.6905 0.32 1.3357 X-Sect 3.9737- D-134 67.6 21.1602 70.9939 0.3 0.9762 X-Sect 4.9411 --- D-133A 67.6 21.1511 93.7984 0.23 1.035 X-Secl 5.0466 --- D-133 67.6 21.1496 26.6671 0.79 2.3487 X-Sect 1.6064 - P-115 68.7 21.6082 6.9473 3.11 -1 12" Diam 3.1103 8.8456 e-004 D-132 68.7 21.605 226.87 0.1 0.9869 X-Sect 7.7628 -- P-114 92.2 28.7909 18.9199 1.52 -1 24" Diam 1.5217 6.0224 e-005 D-131 92.2 28.7784 338.51 0.09 0.9857 X-Sect 6.7585- D-130 92.2 28.7663 33.2703 0.86 1.4508 X-Sect 5.8219 - D-129 92.2 28.7555 8.6723 3.32 -1 X-Sect 3.3158 ---- P-113 92.2 28.7428 23.5738 1 .22 -1 18" Diam 1.2193 13.34 D-128 92.2 28.731 266.41 0.11 1.1405 X-Sect 5.9997 -- D-127 92.2 28.699 1354.11 0.02 0.8231 X-Sect 2.6309- D-126 92.2 28.6712 491.48 0.06 0.4918 X-Sect 2.1506 --- D-125 92.2 28.5445 3470.27 0.01 0.5218 X-Secl 1.1196-- D-124 92.2 28.3566 549.84 0.05 0.5043 X-Sect 0.8666 ---- D-123 92.2 28.3183 3827.85 0.01 0.6073 X-Sect 2.5267- P-112 92.2 28.2813 4.3371 6.52 -1 12" Diam 6.5208 5.5221 D-122 92.2 28.2656 50.2681 0.56 1.4497 X-Sect 3.6834 -- D-121 122.6 35.6853 594.02 0.06 0.5006 X-Sect 14.8923 -e-006 P-111 122.6 35.6419 15.3148 2.33 -1 18" Diam 2.3273 8.6664 D-120 122.6 35.4329 18.2879 1.94 -1 X-Sect 1.9375 -- D-119 122.6 35.3437 17.5281 2.02 -1 X-Sect 2.0164 -- D-118 122.6 35.3278 179.94 0.2 0. 7605 X-Sect 7.315- D-117 122.6 35.308 61.1492 0.58 1.6707 X-Sect 4.0938 -- D-116 122.6 35.2852 27.9865 1.26 -1 X-Sect 1.2608 - D-115 122.6 35.2833 78.2241 0.45 1.9632 X-Sect 5.68- P-110 122.6 35.2651 30.6525 1.15 -1 24" Diam 1.1505 9.757 D-114 122.6 35.2359 47.75 0.74 1 . 8022 X-Sect 5.8823 -- D-113 124.4 35.5397 319.76 0.11 1.2299 X-Sect 8.0881 ---e-007 D-112 124.4 35.5284 1134.16 0.03 0.8726 X-Sect 8.4163 -- D-111 124.4 35.4908 413.21 0.09 1.3677 X-Sect 5.1548 -- , ·• D-110 124.4 35.4602 241.55 0.15 1.2828 X-Sect 5.4622 ----- Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node fl fl fl fl fl fl N-110 408.8728 N-111 N-110 409.8228 -na----na----na-409.8228 411.92 N-112 N-111 410.9377 --na----na----na-410.9377 414.13 N-113 N-112 412.6176 -na----na----na--412.6176 415.64 N-114 N-113 413.2275 --na----na----na-413.2275 415.67 N-115 N-114 414.9305 -na---na---na-414.18 414.08 N-116 N-115 415.8377 -na--na---na-415.8377 416.5 N-117 N-116 416.2331 --na---na--na-416.2331 416.39 N-118 N-117 417.0631 --na--na--na-416.49 416.39 N-119 N-118 417.0166 -na---na---na--416.71 416.61 N-120 N-119 418.4399 -na---na----na-418.24 418.14 N-121 N-120 420.9399 --na---na----na--420.43 420.33 N-122 N-121 421.6109 -na--na----na-421.6109 422.69 N-123 N-122 434.4431 --na--na---na-423.41 423.31 N-124 N-123 426.0499 -na---na--na-423.41 423.31 N-125 N-124 423.6399 -na---na--na-423.6399 424.05 N-126 N-125 506.9789 --na---na--na-424.9 424.8 N-127 N-126 425.6399 --na---na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427.6098 -na--na---na-427.6097 428.27 N-130 N-129 429.6497 -na--na--na-429.4 429.3 N-131 N-130 430.9699 -na--na--na-430.83 430.73 N-132 N-131 432.5004 -na--na---na-432.5004 432.79 N-133 N-132 438.2302 -na--na---na-436.5 436.4 N-134 N-133 436.5119 -na----na---na-436.03 435.93 N-135 N-134 437.85 -na--na---na-437.57 437.47 N-136 N-135 440.3899 --na--na--na--440.25 440.15 N-137 N-136 444.7122 --na---na---na-442.2 442.1 N-137A N-137 442.8699 --na--na---na-441.99 441.89 N-138 N-137A 476.2553 --na---na--na-442.9 442.8 N-139 N-138 443.4986 -na---na--na-442.9 442.8 N-140 N-139 443.8899 --na---na--na-443.14 443.04 N-141 N-140 444.3999 --na----na--na-444.3999 444.84 N-142 N-141 446.0057 --na----na---na-446.0057 446.11 N-143 N-142 447.2256 --na----na---na-447.2256 447.71 N-144 N-143 455.4835 -na----na---na-448.2 448.1 N-145 N-144 448.46 -na----na---na-447.84 447.74 N-146 N-145 449.6399 --na--na--na-449.6399 449.84 N-147 N-146 452. 3699 --na--na---na-452.3698 452.71 N-148 N-147 453.5398 -na--na--na-453.5398 453.89 N-149 N-148 474.9647 --na---na---na-454.3 454.2 N-150 N-149 454.3029 --na--na--na-454.3029 454.65 N-151 N-150 456.4129 -na---na---na-455.87 455.77 N-152 N-151 460.5836 --na--na--na-460.56 460.46 N-153 N-152 463.9726 --na--na--na-463.9726 464.17 N-154 N-153 467 .9025 --na----na--na-467.44 467.34 Table 8.5. Hydrograph Routing -East Basin -1 OD-Year Storm ROUTEHYD [] THRU [Existing East] USING TYPE1A AND [100 yr] NOTZERO ACTUAL Reach Area Flow FullQ % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ------------ D-Dum2 19.7 7.1007 122.33 0.06 0.5932 X-Sect 4. 5504 -----e-001 D-Dum1 53.6 20.334 122.33 0.17 1.0256 X-Sect 6.3154 -----e-002 D-145 53.6 20.3311 121.12 0.17 1.0311 X-Sect 6.2711 -- D-144 53.6 20.3274 117.92 0.17 1.2148 X-Sect 5.9225 ---- D-143 53.6 20.3204 122.41 0.17 1.1183 X-Sect 5.4519 ---- D-142 53.6 20.3129 82.3869 0.25 1.2157 X-Sect 4.9037 ---- D-141 53.6 20.3094 10.3949 1.95 -1 X-Sect 1.9538 -- P-117 65.2 22.46 6.5804 3.41 -1 12" Diam 3.4132 8.3784 ex_east D-140 65.2 22.4518 124.5 0.18 0.8802 X-Sect 4.6208- D-139 65.2 22.4372 117.81 0.19 0.8757 X-Sect 4.9419 -- D-138 65.2 22.4229 94.8108 0.24 1.1329 X-Sect 4.756 -- D-137 67.6 23.3927 279 0.08 0.6862 X-Sect 7.4448 ---e-003 P-116 67.6 23.3835 7.2535 3.22 -1 18" Diam 3.2238 4.1046 D-136 67.6 23.3721 61.7242 0.38 1.2109 X-Sect 5.1805 -- D-135 67.6 23.3475 66.6905 0.35 1.4016 X-Sect 4.08 -- D-134 67.6 23.3353 70.9939 0.33 1.0244 X-Sect 5.0771 --- D-133A 67.6 23.3254 93.7984 0.25 1.0782 X-Sect 5.2133 - D-133 67.6 23.3239 26.6671 0.87 2.4653 X-Sect 1.6511 - P-115 68.7 23.829 6.9473 3.43 -1 12" Diam 3.43 8.8456 e-004 D-132 68.7 23.8256 226.87 0.11 1.0347 X-Sect 7.9743-- P-114 92.2 31.6894 18.9199 1.67 -1 24" Diam 1.6749 6.0224 e-005 D-131 92.2 31.6761 338.51 0.09 1.0378 X-Sect 6.9502- D-130 92.2 31.6628 33.2703 0.95 1.5281 X-Sect 5.9813 - D-129 92.2 31.6529 8.6723 3.65 -1 X-Sect 3.6499 ---- P-113 92.2 31.6395 23.5738 1.34 -1 18" Diam 1.3421 13.34 D-128 92.2 31.627 266.41 0.12 1.2034 X-Sect 6.1704 -- D-127 92.2 31.5932 1354.11 0.02 0.8449 X-Sect 2.6909 -- D-126 92.2 31.5642 491.48 0.06 0.5117 X-Sect 2.2214 --- D-125 92.2 31.4314 3470.27 0.01 0.541 X-Sect 1.1469 ----- D-124 92.2 31.2367 549.84 0.06 0.5301 X-Sect 0.8959 -- D-123 92.2 31.1967 3827.85 0.01 0.6298 X-Sect 2.5886- P-112 92.2 31.1607 4.3371 7.18 -1 12" Diam 7.1847 5.5221 D-122 92.2 31.1444 50.2681 0.62 1.5106 X-Sect 3.8005 -- D-121 122.6 39.4139 594.02 0.07 0.527 X-Sect 15.3819 ---e-006 P-111 122.6 39.3717 15.3148 2.57 -1 18" Diam 2.5708 8.6664 D-120 122.6 39.1738 18.2879 2.14 -1 X-Sect 2.1421 ----- D-119 122.6 39.0873 17.5281 2.23 -1 X-Sect 2.23-- D-118 122.6 39.0705 179.94 0.22 0. 7996 X-Sect 7.5336 --- D-117 122.6 39.0498 61.1492 0.64 1.7492 X-Sect 4.2208 - D-116 122.6 38.9434 27.9865 1.39 -1 X-Sect 1.3915 - D-115 122.6 38.9414 78.2241 0.5 2.0557 X-Sect 5.829-- P-110 122.6 38.9219 30.6525 1.27 -1 24" Diam 1.2698 9.757 D-114 122.6 38.8904 47.75 0.81 1.8838 X-Sect 6.0508 -- D-113 124.4 39.2371 319.76 0.12 1.298 X-Sect 8.3113 ---e-007 D-112 124.4 39.225 1134.16 0.03 0.9129 X-Sect 8.7019 -- D-111 124.4 39.1846 413.21 0.09 1.4411 X-Sect 5.2991 --- D-110 124.4 39.1518 241.55 0.16 1 .3552 X-Sect 5.6219 ----- Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node ft ft ft ft ft ft N-110 408.9452 N-111 N-110 409.8951 --na----na---na-409.8951 411.92 N-112 N-111 411.0111 -na----na----na-411.0111 414.13 N-113 N-112 412.691 --na----na----na--412.691 415.64 N-114 N-113 413.3009 --na----na---na--413.3009 415.67 N-115 N-114 415.03 -na----na----na-414.18 414.08 N-116 N-115 416.0292 -na---na----na--416.0292 416.5 N-117 N-116 416.3256 --na--na--na-416.3256 416.39 N-118 N-117 417.1555 -na---na----na--416.49 416.39 N-119 N-118 417.1629-na--na---na-416.71 416.61 N-120 N-119 418.4399 -na---na---na--418.24 418.14 N-121 N-120 420.9399 -na----na---na--420.43 420.33 N-122 N-121 421.696 -na--na----na--421.696 422.69 N-123 N-122 437.3544 -na----na----na--423.41 423.31 N-124 N-123 426.0499 -na----na---na--423.41 423.31 N-125 N-124 423.6805 --na---na----na--423.6805 424.05 N-126 N-125 524.8533 -na---na--na-424.9 424.8 N-127 N-126 425.6399 --na--na--na-425.6399 426.02 N-128 N-127 426.0798 -na--na--na-426.0798 426.52 N-129 N-128 427 .6098 --na--na---na-427.6097 428.27 N-130 N-129 429.6497 --na--na--na--429.4 429.3 N-131 N-130 430.9699 -na--na---na-430.83 430.73 N-132 N-131 432.5633 --na---na--na-432.5633 432.79 N-133 N-132 439.3671 --na---na----na-436.5 436.4 N-134 N-133 436.5119 --na---na--na-436.03 435.93 N-135 N-134 437.85 --na---na---na-437.57 437.47 N-136 N-135 440.3899 --na---na--na-440.25 440.15 N-137 N-136 445.4762 -na---na---na--442.2 442.1 N-137A N-137 442.8699 --na----na----na--441.99 441.89 N-138 N-137A 483.6605 -na---na---na-442.9 442.8 N-139 N-138 443.6152 -na---na---na-442.9 442.8 N-140 N-139 443.8899 --na---na----na-443.14 443.04 N-141 N-140 444.4243 --na---na---na-444.4243 444.84 N-142 N-141 446.0716 --na----na---na-446.0716 446.11 N-143 N-142 447.2915 --na---na----na-447.2915 447.71 N-144 N-143 457.2313 -na--. -na----na-448.2 448.1 N-145 N-144 448.4599 -na--na--na-447.84 447.74 N-146 N-145 449.6399 -na---na---na-449.6399 449.84 N-147 N-146 452.3698 -na---nil--na-452.3698 452.71 N-148 N-147 453.5398 -na--na--na-453.5398 453.89 N-149 N-148 479.5756 -na--na--na-454.3 454.2 N-150 N-149 454.3031 --na--na--na-454.3031 454.65 N-151 N-150 456.413 --na--na---na-455.87 455.77 N-152 N-151 460.6481 --na----na----na-460.56 460.46 N-153 N-152 464.0445 --na---na--na-464.0445 464.17 N-154 N-153 467.9954 --na---na--na-467.44 467.34 ' ., Table 8.6. Hydrograph Routing -East Basin -Summary Table 2-Year 10-Year 25-Year SO-Year 100-Year Freeboard Freeboard Freeboard Freeboard Freeboard Reach ID From Node To Node (FT) (FT) (FT) (FT) (FT) N-110 D-110 N-111 N-110 2.68 2.33 2.17 2.10 2.02 D-111 N-112 N-111 4.16 3.43 3.27 3.19 3.12 D-112 N-113 N-112 3.98 3.26 3.10 3.02 2.95 D-113 N-114 N-113 3.14 2.69 2.52 2.44 2.37 D-114 N-115 N-114 Overtop Overtop Overtop Overtop Overtop P-110 N-116 N-115 1.00 Overtop Overtop 0.66 0.47 D-115 N-117 N-116 0.83 Overtop Overtop 0.16 0.06 D-116 N-118 N-117 0.00 Overtop Overtop Overtop Overtop D-117 N-119 N-118 Overtop Overtop Overtop Overtop Overtop D-118 N-120 N-119 Overtop Overtop Overtop Overtop Overtop D-119 N-121 N-120 Overtop Overtop Overtop Overtop Overtop D-120 N-122 N-121 1.17 1.36 1.17 1.08 0.99 P-111 N-123 N-122 0.32 Overtop Overtop Overtop Overtop D-121 N-124 N-123 Overtop Overtop Overtop Overtop Overtop D-122 N-125 N-124 0.41 0.41 0.41 0.41 0.37 P-112 N-126 N-125 Overtop Overtop Overtop Overtop Overtop D-123 N-127 N-126 0.38 0.38 0.38 0.38 0.38 D-124 N-128 N-127 0.44 0.44 0.44 0.44 0.44 D-125 N-129 N-128 0.66 0.66 0.66 0.66 0.66 D-126 N-130 N-129 Overtop Overtop Overtop Overtop Overtop D-127 N-131 N-130 Overtop Overtop Overtop Overtop Overtop D-128 N-132 N-131 0.34 0.34 0.34 0.29 0.23 P-113 N-133 N-132 Overtop Overtop Overtop Overtop Overtop D-129 N-134 N-133 Overtop Overtop Overtop Overtop Overtop D-130 N-135 N-134 Overtop Overtop Overtop Overtop Overtop D-131 N-136 N-135 Overtop Overtop Overtop Overtop Overtop P-114 N-137 N-136 0.68 Overtop Overtop Overtop Overtop D-132 N-137A N-137 Overtop Overtop Overtop Overtop Overtop P-115 N-138 N-137A Overtop Overtop Overtop Overtop Overtop D-133 N-139 N-138 Overtop Overtop Overtop Overtop Overtop D-133A N-140 N-139 Overtop Overtop Overtop Overtop Overtop D-134 N-141 N-140 0.44 0.44 0.44 0.44 0.42 D-135 N-142 N-141 0.44 0.32 0.17 0.10 0.04 D-136 N-143 N-142 0.82 0.70 0.55 0.48 0.42 P-116 N-144 N-143 Overtop Overtop Overtop Overtop Overtop D-137 N-145 N-144 Overtop Overtop Overtop Overtop Overtop D-138 N-146 N-145 0.20 0.20 0.20 0.20 0.20 D-139 N-147 N-146 0.34 0.34 0.34 0.34 0.34 D-140 N-148 N-147 0.35 0.35 0.35 0.35 0.35 P-117 N-149 N-148 Overtop Overtop Overtop Overtop Overtop D-141 N-150 N-149 0.35 0.35 0.35 0.35 0.35 D-142 N-151 N-150 Overtop Overtop Overtop Overtop Overtop D-143 N-152 N-151 Overtop Overtop Overtop Overtop Overtop D-144 N-153 N-152 0.28 0.28 0.27 0.20 0.13 D-145 N-154 N-153 Overtop Overtop Overtop Overtop Overtop Table B.7. Hydrograph Routing -West Basin -2-Year Storm ROUTEHYD O THRU [Existing West] USING TYPE1A AND [2 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ----------- 0-021 2.9 0.5767 215.99 0 0.3321 X-Sect 3.0535 ----w-001 0-020 2.9 0.5766 75.0242 0.01 0.3244 X-Sect 2.7143 ---- P-016 19.2 2.8102 10.5228 0.27 0.3529 12" Diam 11.3425 13.398 w-002 0-019 19.2 2.8096 212.76 0.01 0.6667 X-Sect 4.1816 ----- 0-018 21.1 3.0333 251.93 0.01 0.2382 X-Sect 5.8108 --ex_west P-015 21.1 3.0325 7.7298 0.39 0.4351 12" Diam 9.2462. 9.8418 0-017 21.1 3.0318 138.18 0.02 0.3561 X-Sect 3.5277 -- 0-016 21.1 3.0316 452.04 0.01 0 .254 X-Sect 5.0894 --- P-014 22.3 3.2439 7.9881 0.41 0.4436 12" Diam 9.6423 1 o .1708 w-003 0-015 22.3 3.2432 160.64 0.02 0.451 X-Sect 3.7541 ---- 0-014 22.3 3.2429 200 0.02 0.6317 X-Sect 4.3238 --- P-013 22.3 3.2423 10.6228 0.31 0.3791 12" Diam 11.8787 13.5253 0-012 22.3 3.2413 290.67 0.01 0.6234 X-Sect 4.8101 --- 0-011 22.3 3.2403 320.43 0.01 0.3609 X-Sect 4.0339 --- 0-010 25.5 3.7564 1040.88 0 0.5771 X-Sect 6.1421 ---w-004 P-012 25.5 3.7551 7.0631 0.53 0.5186 12" Diam 9.1309 8.9931 P-011 25.5 3.7536 6.9402 0.54 0.5239 12" Diam 9.0097 8.8365 P-010 25.5 3.7521 8.217 0.46 0.4742 12" Diam 10.2249 10.4623 P-009 25.5 3.7507 7.6431 0.49 0.4945 12" Diam 9.6859 9.7315 P-008A 27.7 4.1444 4.8684 0.85 0.709 12" Diam 6.9597 6.1986 w-005 P-008 31.5 4.8063 6.8722 0.7 0.6161 12" Diam 9.4657 8.75 w-006 P-007 31.5 4.8057 6.4104 0.75 0.6459 12" Diam 8.9569 8.162 P-006 31.5 4.8039 7.4569 0.64 0.5839 12" Diam 10.0875 9.4945 P-005 39.3 6.248 9.9629 0.63 0.574 12" Diam 13.3954 12. 6852 w-007 P-004 . 39.3 6.2406 7.7824 0.8 0.6778 12" Diam 11.0133 9.9088 0-009 39.3 6.2233 93.993 0.07 0.6278 X-Sect 2.79 --- 0-008 39.3 6.2231 112.96 0.06 0.414 X-Sect 6.2056 -- P-003 39.3 6.2205 6.2952 0.99 0.8091 12" Diam 9.1373 8.0153 0-007 39.3 6.2079 107.57 0.06 0.5256 X-Sect 3.8357 ---- 0-006 39.3 6.2077 964.56 0.01 0.3936 X-Sect 8.1166 --- P-002 39.3 6.204 6.1462 1.01 0.8284 12" Diam 8.9179 7.8256 0-005 39.3 6.2035 ---0 0.915 X-Sect 2.1497 ---- 0-004 39.3 6.1864 44.3354 0.14 0.5256 X-Sect 4.8288 -- D-003 39.3 6.1853 313.41 0.02 0.5341 X-Sect 4.3358 -- 0-002 39.3 6.1799 770.99 0.01 0.6454 X-Sect 1.5651 --- 0-001 39.3 6.1797 146.32 0.04 0.4209 X-Sect 7.1705 -- P-001 48.3 6.7994 8.2043 0.83 0.6946 12" Diam 11.6778 10.4461 w-008 Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.6321 N-002 N-001 382.2466 -na---na----na-380.5 380.4 N-003 N-002 381 . 0999 -na--na--na--380.43 380.33 N-004 N-003 382.8899 -na--na--na-382.3 382.2 N-005 N-004 389.8769 -na---na---na-389.8769 390.25 N-006 N-005 398.3768 -na----na----na--398.3768 398.68 N-007 N-006 397. 7699 --na----na----na--397.7699 398.68 N-008 N-007 400.6486 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.4899 --na----na----na-400.32 400.22 N-012 N-011 403.3211 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 --na---na----na--402.4099 402.6 N-016 N-015 406.8691 0.9827 0. 0089 ------405.8952 406.01 N-017 N-016 407.6445 0.5809 0.0075 ------406.41 406.31 N-018 N-017 408.2272 0.5814 0. 0023 ------407.6481 408.14 N-019 N-018 411.1539 -----411.1539 413.72 N-019A N-019 419.722 0.4324 0.0032 ----419.2928 420.68 N-020 N-019A 420.102 -----420.102 422.5 N-021 N-020 428.8048 0.3544 0.0039 ---428.4543 429.85 N-022 N-021 431.8735 1.2605 0.0049 -----430.6179 434 N-023 N-022 435.9002 0.355 0.0013 -----435.5465 436.59 N-024 N-023 437.2402 --na---na----na--437.2402 438.2 N-025 N-024 437.6302 --na---na---na--437.6302 438.9 N-026 N-025 440.4301 --na----na---na--440.4301 441.52 N-028 N-026 444.3401 --na----na---na-444.3401 444.82 N-029 N-028 445.7641 --na--na----na--445.764 446.2 N-031 N-029 445.934 -na---na--na--445.934 446.47 N-032 N-031 447.8239 -na--na---na--447.8239 449.01 N-033 N-032 448.994 -na--na---na-448.994 450.1 N-035 N-033 449.4039 --na---na---na-449.4039 451.24 N-036 N-035 451.6238 -na--na---na-451.6238 452.98 N-037 N-036 452.5651 -na---na----na-452.5651 453.8 N-039 N-037 453.065 --na----na---na--453.065 454.27 N-040 N-039 455.835 --na----na--na--455.835 457.02 N-041 N-040 458.6864 --na---na----na-458.6864 459.3 N-043 N-041 458.8464 -na---na----na-458.8463 459.71 N-044 N-043 466.1862 --na---na----na--466.1862 467.86 Table B.8. Hydrograph Routing -West Basin -10-Year Storm ROUTEHYD O THRU [Existing West] USING TYPE1A AND [10 yr] NOTZERO ACTUAL Reach Area Flow FullQ % Full nDepth Size nVel Nel CBasin I Hyd ac els els ratio ft ft/s ft/s ---------- D-021 2.9 1.1262 215.99 0.01 0.4269 X-Sect 3.6099 -----w-001 D-020 2.9 1.126 75.0242 0.02 0.417 X-Sect 3.2085 --- P-016 19.2 5.7252 10.5228 0.54 0.5258 12" Diam 13.6802 13.398 w-002 D-019 19.2 5.7243 212.76 0.03 0.8706 X-Sect 4.9958 ----- D-018 21.1 6.2369 251.93 0.02 0.3597 X-Seci 7.2932 ---ex_west P-015 21.1 6.2355 7.7298 0.81 0.6807 12" Diam 10.9508 9.8418 D-017 21.1 6.2346 138.18 0.05 0.5336 X-Seci 4.3923 -- D-016 21.1 6.2343 452.04 0.01 0.3664 X-Seci 6.4244- P-014 22.3 6.6546 7.9881 0.83 0.6973 12" Diam 11.3797 10.1708 w-003 D-015 22.3 6.6534 160.64 0.04 0.6285 X-Seci 4.6707- D-014 22.3 6.653 200 0.03 0.827 X-Sect 5.1746 - P-013 22.3 6.652 10.6228 0.63 0.5735 12" Diam 14.2771 13.5253 D-012 22.3 6.6504 290.67 0.02 0.8162 X-Seci 5.757- D-011 22.3 6.6488 320.43 0.02 0.516 X-Seci 5.0632 -- D-010 25.5 7.6794 1040.88 0.01 0. 7546 X-Seci 7.3444-w-004 P-012 25.5 7.6772 7.0631 1.09 -1 12" Diam 1.0869 8.9931 P-011 25.5 7.6747 6.9402 1.11 -1 12" Diam 1.1058 8.8365 P-010 25.5 7.6721 8.217 0.93 0.7657 12" Diam 11.8884 10.4623 P-009 25.5 7.6702 7.6431 1 0.8229 12" Diam 11.0927 9.7315 P-008A 27.7 8.4447 4.8684 1.73 -1 12" Diam 1.7346 6.1986 w-005 P-008 31.5 9.6483 6.8722 1.4 -1 12" Diam 1.404 8.75 w-006 P-007 31.5 9.6459 6.4104 1.5 -1 12" Diam 1.5047 8.162 P-006 31.5 9.6425 7.4569 1.29 -1 12" Diam 1.2931 9.4945 P-005 39.3 12.2397 9.9629 1.23 -1 12· Diam 1.2285 12.6852 w-007 P-004 39.3 12.2337 7.7824 1.57 -1 12" Diam 1.572 9.9088 D-009 39.3 12.2305 93.993 0.13 0.867 X-Sect 3.43 -- D-008 39.3 12.2302 112.96 0.11 0.5807 X-Seci 7.6019 - P-003 39.3 12.2269 6.2952 1.94 -1 12" Diam 1.9423 8.0153 D-007 39.3 12.2225 107.57 0.11 0.7439 X-Sect 4.7079 - D-006 39.3 12.2223 964.56 0.01 0.5074 X-Sect 9.6143 -- P-002 39.3 12.2172 6.1462 1.99 -1 12" Diam 1.9878 7.8256 D-005 39.3 12.2169 -0 0.915 X-Sect 4.2335 --- D-004 39.3 12.207 44.3354 0.28 0. 7349 X-Sect 5.8637 --- D-003 39.3 12.1945 313.41 0.04 0. 7226 X-Sect 5.3815- D-002 39.3 12.1624 770.99 0.02 0. 7234 X-Sect 1.7335 - D-001 39.3 12.1621 146.32 0.08 0.5527 X-Seci 8.9201 - P-001 48.3 13.7386 8.2043 1.67 -1 12" Diam 1.6746 10.4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.66 N-002 N-001 397.4953 -na---na---na--380.5 380.4 N-003 N-002 381.0999 -na---na---na-380.43 380.33 N-004 N-003 382.8899 -na---na--na-382.3 382.2 N-005 N-004 390.363 -na--na---na-390.35 390.25 ' ., N-006 N-005 398.8499 --na----na----na--398.78 398.68 N-Q07 N-006 398.1499 --na----na----na-398.1499 398.68 N-008 N-007 406.7091 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.4899 --na----na----na--400.32 400.22 N-012 N-011 402.893 --na----na----na-401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 --na----na----na--402.4099 402.6 N-016 N-015 414.9783 3.7712 0.0341 -----406.11 406.01 N-017 N-016 412.823 2.3405 0.0303 ··-··· 406.41 406.31 N-018 N-017 412.9798 2.3422 0.0092 -----408.24 408.14 N-019 N-018 421.5153 ··-·· 413.82 413.72 N-019A N-019 428.7839 1.7952 0.0134 ----420.78 420.68 N-020 N-019A 424.1394 ·--· 422.6 422.5 N-021 N-020 431.693 1.4817 0.0162 --··· 429.95 429.85 N-022 N-021 431.8735 1.4827 0.0057 ·---430.3965 434 N-023 N-022 438.0848 1.4837 0.0053 -----436.69 436.59 N-024 N-023 440.4391 --na----na----na-438.3 438.2 N-025 N-024 438.69 --na----na----na-438.69 438.9 N-026 N-025 441 .4899 --na---na----na-441.4899 441.52 N-028 N-026 445.3998 --na----na---na--444.92 444.82 N-029 N-028 447.9408 --na----na----na--446.3 446.2 N-031 N-029 446.47 --na----na----na-446.47 446.47 N-032 N-031 448.3599 --na---na--na-448.3599 449.01 N-033 N-032 451.1722 --na---na----na-450.2 450.1 N-035 N-033 450.6099 -na--na---na-450.6099 451.24 N-036 N-035 452.8299 --na----na----na-452.8299 452.98 N-037 N-036 454.9681 -na---na---na-453.9 453.8 N-039 N-037 454.3999 --na----na----na-454.37 454.27 N-040 N-039 457.14 --na----na----na-457.12 457.02 N-041 N-040 460.2915 --na--na---na--459.4 459.3 N-043 N-041 459.5599 --na----na---na-459.5599 459.71 N-044 N-043 466.8998 --na----na----na--466.8998 467.86 , ' Table B.9. Hydrograph Routing -West Basin -25-Year Stonn ROUTEHYD [] THRU [Existing West] USING TYPE1A AND [25 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDeplh Size nVel Nel CBasin / Hyd ac cfs cfs ratio fl ft/s fl/s ----------- D-021 2.9 1.4193 215.99 0.01 0.4655 X-Sect 3.8249 ----w-001 D-020 2.9 1.419 75.0242 0.02 0.4548 X-Sect 3.3995 ---- P-016 19.2 7.2941 10.5228 0.69 0.6125 12" Diam 14.4658 13.398 w-002 D-019 19.2 7.2903 212.76 0.03 0.9533 X-Sect 5.3071 ----- D-018 21.1 7.9622 251.93 0.03 0.4124 X-Sect 7.8517 -----ex_west P-015 21.1 7.9606 7.7298 1.03 0.8494 12" Diam 11.1952 9.8418 D-017 21.1 7.9596 138.18 0.06 0.6103 X-Sect 4.7161 --- D-016 21.1 7.9593 452.04 0.02 0.4154 X-Sect 6.9302 -- P-014 22.3 8.4903 7.9881 1.06 0.8943 12" Diam 11.4571 10.1708 w-003 D-015 22.3 8.4889 160.64 0.05 0. 7052 X-Sect 5.0142 -- D-014 22.3 8.4884 200 0.04 0.9062 X-Sect 5.4996 ----- P-013 22.3 8.4872 10.6228 0.8 0.676 12" Diam 15.0227 13.5253 D-012 22.3 8.4854 290.67 0.03 0.8943 X-Sect 6.1186 -- D-011 22.3 8.4835 320.43 0.03 0.5836 X-Sect 5.4511 ---- D-010 25.5 9.7892 1040.88 0.01 0.8265 X-Sect 7.8039 --w-004 P-012 25.5 9.7867 7.0631 1.39 -1 12" Diam 1.3856 8.9931 P-011 25.5 9.7842 6.9402 1.41 -1 12" Diam 1.4098 8.8365 P-010 25.5 9.7811 8.217 1.19 -1 12" Diam 1.1903 10.4623 P-009 25.5 9.7791 7.6431 1.28 -1 12" Diam 1.2795 9.7315 P-008A 27.7 10.7564 4.8684 2.21 -1 12" Diam 2.2095 6.1986 w-005 P-008 31.5 12.2532 6.8722 1.78 -1 12" Diam 1.783 8.75 w-006 P-007 31.5 12.2295 6.4104 1.91 -1 12" Diam 1.9077 8.162 P-006 31.5 12.214 7.4569 1.64 -1 12" Diam 1.6379 9.4945 P-005 39.3 15.4537 9.9629 1.55 -1 12" Diam 1.5511 12.6852 w-007 P-004 39.3 15.439 7.7824 1.98 -1 12" Diam 1.9838 9.9088 D-009 39.3 15.4332 93.993 0.16 0.9703 X-Sect 3.6728 -- D-008 39.3 15.4329 112.96 0.14 0.6524 X-Sect 8.1307 - P-003 39.3 15.4277 6.2952 2.45 -1 12" Diam 2.4507 8.0153 D-007 39.3 15.4211 107.57 0.14 0.8378 X-Sect 5.0372 --- D-006 39.3 15.4209 964.56 0.02 0.5537 X-Sect 10.1896 ---- P-002 39.3 15.4136 6.1462 2.51 -1 12" Diam 2.5078 7.8256 D-005 39.3 15.4133 ---0 0.915 X-Sect 5.3412 ---- D-004 39.3 15.3973 44.3354 0.35 0.8232 X-Sect 6.2522- D-003 39.3 15.3784 313.41 0.05 0.8043 X-Sect 5.7771 -- D-002 39.3 15.3305 770.99 0.02 0.749 X-Sect 1.8482 - D-001 39.3 15.3302 146.32 0.1 0.61 X-Sect 9.5841 ---- P-001 48.3 17.4789 8.2043 2.13 -1 12" Diam 2.1304 1 O .4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node fl ft ft ft ft ft N-001 373.66 N-002 N-001 412.2399 -na--na--na-380.5 380.4 N-003 N-002 381.1 -na--na--na-380.43 380.33 N-004 N-003 382.8899 --na--na--na-382.3 382.2 N-005 N-004 390.6017 --na--na---na--390.35 390.25 N-006 N-005 398.85 --na----na----na--398.78 398.68 N-007 N-006 398.1499 --na----na----na--398.1499 398.68 N-008 N-007 411.7735 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.4899 --na----na----na--400.32 400.22 N-012 N-011 404.2625 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 --na----na----na--402.4099 402.6 N-016 N-015 422.4271 6.0118 0. 0544 -----406.11 406.01 N-017 N-016 416.8114 3.7554 0. 0486 -----406.41 406.31 N-018 N-017 416.9514 3.7649 0.0148 -----408.24 408.14 N-019 N-018 429.5789 ------413.82 413.72 N-019A N-019 437.9548 2.9125 0.0218 -----420.78 420.68 N-020 N-019A 426.2303 -----422.6 422.5 N-021 N-020 436.8487 2.4083 0. 0264 -----429.95 429.85 N-022 N-021 438.8036 2.4098 0. 0093 -----434.1 434 N-023 N-022 442.3643 2.4111 0.0087 -----436.69 436.59 N-024 N-023 442.7826 --na----na----na-438.3 438.2 N-025 N-024 438.69 --na----na----na-438.69 438.9 N-026 N-025 441.4899 --na----na---na-441.4899 441.52 N-028 N-026 445.3998 --na----na----na-444.92 444.82 N-029 N-028 449. 7335 --na----na----na-446.3 446.2 N-031 N-029 446.47 --na---na----na-446.47 446.47 N-032 N-031 448.3599 --na----na---na-448.3599 449.01 N-033 N-032 452.966 --na----na--na--450.2 450.1 N-035 N-033 450.6099 -na----na---na-450.6099 451.24 N-036 N-035 452.8299 -na---na---na-452.8299 452.98 N-037 N-036 456.3148 -na---na---na-453.9 453.8 N-039 N-037 454.3999 -na----na---na--454.37 454.27 N-040 N-039 457 .1399 --na----na--na--457.12 457.02 N-041 N-040 461.6094 -na---na---na--459.4 459.3 N-043 N-041 459.5599 --na---na--na--459.5599 459.71 N-044 N-043 466.8998 --na----na----na--466.8998 467.86 Table B.10. Hydrograph Routing -West Basin -50-Year Storm ROUTEHYD O THRU [Existing Wes1] USING TYPE1A AND [50 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs cfs ratio ft ft/s ft/s ---------- 0-021 2.9 1.5685 215.99 0.01 0.4833 X-Sect 3.9215 -----w-001 D-020 2.9 1.5683 75.0242 0.02 0.4722 X-Sect 3.4853 -- P-016 19.2 8.0999 10.5228 0.77 0.6581 12" Diam 14.7787 13.398 w-002 D-019 19.2 8.0896 212.76 0.04 0.9912 X-Sect 5.4469 -- D-018 21.1 8.8435 251.93 0.04 0.4372 X-Sect 8.1008 ----ex_west P-015 21.1 8.8417 7.7298 1.14 -1 12" Diam 1.1439 9.8418 D-017 21.1 8.8407 138.18 0.06 0.6463-X-Sect 4.8603 --- D-016 21.1 8.8404 452.04 0.02 0.4384 X-Sect 7.156 -- P-014 22.3 9.434 7.9881 1.18 -1 12" Diam 1.181 10.1708 w-003 D-015 22.3 9.4262 160.64 0.06 0.7412 X-Sect 5.1673 --- D-014 22.3 9.4257 200 0.05 0. 9425 X-Sect 5.6454 ----- P-013 22.3 9.4245 10.6228 0.89 0.7329 12" Diam 15.2781 13.5253 D-012 22.3 9.4224 290.67 0.03 0.9301 X-Sect 6.2809 -- D-011 22.3 9.4204 320.43 0.03 0.6154 X-Sect 5.6241 --- D-010 25.5 10.8663 1040.88 0.01 0.8595 X-Sect 8.0101 --w-004 P-012 25.5 10.8659 7.0631 1.54 -1 12" Diam 1.5384 8.9931 P-011 25.5 10.8622 6.9402 1.57 -1 12" Diam 1.5651 8.8365 P-010 25.5 10.8581 8.217 1.32 -1 12" Diam 1.3214 10.4623 P-009 25.5 10.8544 7.6431 1.42 -1 12" Diam 1.4201 9.7315 P-008A 27.7 11.9326 4.8684 2.45 -1 12" Diam 2.4511 6.1986 w-005 P-008 31.5 13.5621 6.8722 1.97 -1 12" Diam 1.9735 8.75 w-006 P-007 31.5 13.5297 6.4104 2.11 -1 12" Diam 2.1106 8.162 P-006 31.5 13.5123 7.4569 1.81 -1 12" Diam 1.8121 9.4945 P-005 39.3 17.0801 9.9629 1.71 -1 12" Diam 1.7144 12.6852 w-007 P-004 39.3 17.0634 7.7824 2.19 -1 12" Diam 2.1926 9.9088 D-009 39.3 17.0568 93.993 0.18 1.0185 X-Sect 3.7809- D-008 39.3 17.0564 112.96 0.15 0.6858 X-Sect 8.366 --- P-003 39.3 17.0509 6.2952 2.71 -1 12" Diam 2.7086 8.0153 D-007 39.3 17.0435 107.57 0.16 0.8816 X-Sect 5.1838 ---- D-006 39.3 17.0432 964.56 0.02 0.5748 X-Sect 10.4477- P-002 39.3 17.0355 6.1462 2.77 -1 12" Diam 2.7717 7.8256 D-005 39.3 17.0353 --0 0.915 X-Sect 5.9032 -- D-004 39.3 17.0172 44.3354 0.38 0.8642 X-Sect 6.4254 -- D-003 39.3 16.9961 313.41 0.05 0.8428 X-Sect 5.9539- D-002 39.3 16.9427 770.99 0.02 0. 7591 X-Sect 1.9232 ---- D-001 39.3 16.9424 146.32 0.12 0.6369 X-Sect 9.8817 -- P-001 48.3 19.3916 8.2043 2.36 -1 12" Diam 2.3636 10.4461 w-008 Reh App Bend June! HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.66 N-002 N-001 421.1453 -na---na---na--380.5 380.4 N-003 N-002 381.1 -na--na---na-380.43 380.33 N-004 N-003 382.8899 -na---na---na-382.3 382.2 N-005 N-004 390.6621 -na---na--na--390.35 390.25 N-006 N-005 398.8499 --na----na----na--398.78 398.68 N-007 N-006 398.1499 --na----na----na--398.1499 398.68 N-008 N-007 414.7916 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.5191 --na----na----na-400.32 400.22 N-012 N-011 405.0781 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 --na----na----na--402.4099 402.6 N-016 N-015 426.8611 7.3437 0.0665 ------406.11 406.01 N-017 N-016 419.1824 4.5962 0.0595 -----406.41 406.31 N-018 N-017 419.3115 4.6079 0.0181 -----408.24 408.14 N-019 N-018 434.3575 ------413.82 413.72 N-019A N-019 443.3864 3.5843 0.0268 ----420.78 420.68 N-020 N-019A 427.4875 ------422.6 422.5 N-021 N-020 440.1545 2.9679 0.0325 -----429.95 429.85 N-022 N-021 440.8607 2.9701 0.0115 -----· 434.1 434 N-023 N-022 444.2857 2.9721 0.0107 ------436.69 436.59 N-024 N-023 444.2004 --na----na----na--438.3 438.2 N-025 N-024 438.6899 --na----na----na-438.6899 438.9 N-026 N-025 441 .4899 --na----na----na--441.4899 441.52 N-028 N-026 445.3998 --na----na----na--444.92 444.82 N-029 N-028 450. 8166 --na----na---na-446.3 446.2 N-031 N-029 446.47 --na---na---na-446.47 446.47 N-032 N-031 448.3599 --na----na----na-448.3599 449.01 N-033 N-032 453.324 -na---na---na-450.2 450.1 N-035 N-033 450. 6099 -na----na---na--450.6099 451.24 N-036 N-035 452.8299 --na---na--na-452.8299 452.98 N-037 N-036 457.129 --na---na--na-453.9 453.8 N-039 N-037 454.3999 --na----na----na--454.37 454.27 N-040 N-039 457 .1399 --na----na----na--457.12 457.02 N-041 N-040 462.4097 --na--na---na--459.4 459.3 N-043 N-041 459. 5599 -na---na----na--459.5599 459.71 N-044 N-043 466.8998 --na----na---na--466.8998 467.86 Table B.11. Hydrograph Routing -West Basin -100-Year Stonn ROUTEHYD O THRU [Existing West) USING TYPE1A AND [100 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd ac cfs els ratio ft ft/s ft/s ------------ D-021 2.9 1.7191 215.99 0.01 0.5002 X-Sect 4.0124 -----w-001 D-020 2.9 1.7188 75.0242 0.02 0.4887 X-Sect 3.5662 ----- P-016 19.2 8.9147 10.5228 0.85 0.7064 12" Diam 15 0315 13. 398 w-002 D-019 19.2 8.8982 212.76 0.04 1 . 0272 X-Sect 5.5783 ----- D-018 21.1 9.7341 251.93 0.04 0.4611 X-Sect 8.3334 -----ex_west P-015 21.1 9.7323 7.7298 1.26 -1 12" Diam 1.2591 9.8418 D-017 21.1 9.7313 138.18 0.07 0.6809 X-Sect 4.9949 ~--- D-016 21.1 9.7309 452.04 0.02 0.4605 X-Sect 7.3672 ----- P-014 22.3 10.3918 7.9881 1.3 -1 12" Diam 1.3009 10.1708 w-003 D-015 22.3 10.3745 160.64 0.06 0.7757 X-Sect 5.3102 ----- D-014 22.3 10.3736 200 0.05 0.977 X-Sect 5.7823 ---- P-013 22.3 10.3718 10.6228 0.98 0.7991 12" Diam 15.4151 13.5253 D-012 22.3 10.3694 290.67 0.04 0. 9642 X-Sect 6.4331 ---- D-011 22.3 10.3672 320.43 0.03 0.6459 X-Sect 5.7856 ---- D-010 25.5 11.9547 1040.88 0.01 0. 8908 X-Sect 8.2036 --w-004 P-012 25.5 11.9546 7.0631 1.69 -1 12" Diam 1.6925 8.9931 P-011 25.5 11.9518 6.9402 1.72 -1 12" Diam 1.7221 8.8365 P-010 25.5 11.9391 8.217 1.45 -1 12" Diam 1.453 10.4623 P-009 25.5 11.8994 7.6431 1.56 -1 12" Diam 1.5569 9.7315 P-008A 27.7 13.0768 4.8684 2.69 -1 12" Diam 2.6861 6.1986 w-005 P-008 31.5 14.8216 6.8722 2.16 -1 12" Diam 2.1567 8.75 w-006 P-007 31.5 14.7641 6.4104 2.3 -1 12" Diam 2.3031 8.162 P-006 31.5 14.7397 7.4569 1.98 -1 12" Diam 1.9766 9.4945 P-005 39.3 18.6376 9.9629 1.87 -1 12" Diam 1.8707 12.6852 w-007 P-004 39.3 18.6131 7.7824 2.39 -1 12" Diam 2.3917 9.9088 D-009 39.3 18.6037 93.993 0.2 1.0612 X-Sect 3.8828 -- D-008 39.3 18.6034 112.96 0.16 0. 7161 X-Sect 8.5744 ---- P-003 39.3 18.5959 6.2952 2.95 -1 12" Diam 2.954 8.0153 D-007 39.3 18.5866 107.57 0.17 0.9214 X-Sect 5.3133 ----- D-006 39.3 18.5863 964.56 0.02 0.5938 X-Sect 10.6766 ----- P-002 39.3 18.5762 6.1462 3.02 -1 12" Diam 3.0224 7.8256 D-005 39.3 18.576 -0 0.915 X-Sect 6.4371 ---- D-004 39.3 18.5514 44.3354 0.42 0.9012 X-Sect 6.5778 ---- D-003 39.3 18.5234 313.41 0.06 0.8774 X-Sect 6.1089 --- D-002 39.3 18.4536 770.99 0.02 0.7682 X-Sect 1.9897 -- D-001 39.3 18.4532 146.32 0.13 0.6611 X-Sect 10.141 ----- P-001 48.3 21.1994 8.2043 2.58 -1 12" Diam 2.5839 10.4461 w-008 Reh App Bend Junct HW Max El/ Loss Head Loss Loss Elev Rim El From Nod To Node ft ft ft ft ft ft N-001 373.66 N-002 N-001 430.4121 --na---na---na-380.5 380.4 N-003 N-002 381.0999 -na--na---na--380.43 380.33 N-004 N-003 382.8899 --na----na----na--382.3 382.2 N-005 N-004 390.6975 --na--na---na--390.35 390.25 ·\ N-006 N-005 398.8499 -na----na----na--398.78 398.68 N-007 N-006 398. 1499 --na----na----na--398.1499 398.68 N-008 N-007 417.9379 --na----na----na--399.4 399.3 N-010 N-008 400.3799 --na----na----na--399.4 399.3 N-011 N-010 400.5711 --na----na----na--400.32 400.22 N-012 N-011 405.9302 --na----na----na--401.7 401.6 N-014 N-012 401.9299 --na----na----na--401.9 401.8 N-015 N-014 402.4099 -na----na----na--402.4099 402.6 N-016 N-015 431.5039 8.7441 0.0791 ------406.11 406.01 N-017 N-016 421.6752 5.469 0.0707 ------406.41 406.31 N-018 N-017 421.7617 5.4872 0.0216 ------408.24 408.14 N-019 N-018 439.3409 -----413.82 413.72 N-019A N-019 449.133 4.3046 0. 0322 -----420.78 420.68 N-020 N-019A 428.8355 -----422.6 422.5 N-021 N-020 443.6975 3.5882 0.0393 ----429.95 429.85 N-022 N-021 443.1411 3.5959 0.0139 -----434.1 434 N-023 N-022 446.4317 3.5976 0.0129 ------436.69 436.59 N-024 N-023 445. 7808 --na---na----na--438.3 438.2 N-025 N-024 438.6899 -na---na----na--438.6899 438.9 N-026 N-025 441.4899 --na---na---na--441.4899 441.52 N-028 N-026 445.3998 --na----na---na--444.92 444.82 N-029 N-028 452.0266 -na----na----na-446.3 446.2 N-031 N-029 446.47 -na---na---na--446.47 446.47 N-032 N-031 448.3599 -na--na--na--448.3599 449.01 N-033 N-032 454.3832 -na---na---na-450.2 450.1 N-035 N-033 450.6099 -na----na---na-450.6099 451.24 N-036 N-035 452.8299 -na--na---na-452.8299 452.98 N-037 N-036 458.0387 -na--na---na--453.9 453.8 N-039 N-037 454.3999 --na--na----na--454.37 454.27 N-040 N-039 457.1399 --na----na----na-457.12 457.02 N-041 N-040 463.3042 -na----na----na--459.4 459.3 N-043 N-041 459 .5599 --na----na----na--459.5599 459.71 N-044 N-043 466.8998 -na----na----na--466.8998 467.86 Table 8.12. Hydrograph Routing -West Basin -Summary Table 2-Year 10-Year 25-Year 50-Year 100-Year Freeboard Freeboard Freeboard Freeboard Freeboard Reach ID From Node To Node ft ft ft ft ft N-001 P-001 N-002 N-001 Overtop Overtop Overtop Overtop Overtop D-001 N-003 N-002 Overtop Overtop Overtop Overtop Overtop D-002 N-004 N-003 Overtop Overtop Overtop Overtop Overtop D-003 N-005 N-004 0.37 Overtop Overtop Overtop Overtop D-004 N-006 N-005 0.30 Overtop Overtop Overtop Overtop D-005 N-007 N-006 0.91 0.53 0.53 0.53 0.53 P-002 N-008 N-007 Overtop Overtop Overtop Overtop Overtop D-006 N-010 N-008 Overtop Overtop Overtop Overtop Overtop D-007 N-011 N-010 Overtop Overtop Overtop Overtop Overtop P-003 N-012 N-011 Overtop Overtop Overtop Overtop Overtop D-008 N-014 N-012 Overtop Overtop Overtop Overtop Overtop D-009 N-015 N-014 0.19 0.19 0.19 0.19 0.19 P-004 N-016 N-015 0.11 Overtop Overtop Overtop Overtop P-005 N-017 N-016 Overtop Overtop Overtop Overtop Overtop P-006 N-018 N-017 0.49 Overtop Overtop Overtop Overtop P-007 N-019 N-018 2.57 Overtop Overtop Overtop Overtop P-008 N-019A N-019 1.39 Overtop Overtop Overtop Overtop P-008A N-020 N-019A 2.40 Overtop Overtop Overtop Overtop P-009 N-021 N-020 1.40 Overtop Overtop Overtop Overtop P-010 N-022 N-021 3.38 3.60 Overtop Overtop Overtop P-011 N-023 N-022 1.04 Overtop Overtop Overtop Overtop P-012 N-024 N-023 0.96 Overtop Overtop Overtop Overtop D-010 N-025 N-024 1.27 0.21 0.21 0.21 0.21 D-011 N-026 N-025 1.09 0.03 0.03 0.03 0.03 D-012 N-028 N-026 0.48 Overtop Overtop Overtop Overtop P-013 N-029 N-028 0.44 Overtop Overtop Overtop Overtop D-014 N-031 N-029 0.54 0.00 0.00 0.00 0.00 D-015 N-032 N-031 1.19 0.65 0.65 0.65 0.65 P-014 N-033 N-032 1.11 Overtop Overtop Overtop Overtop D-016 N-035 N-033 1.84 0.63 0.63 0.63 0.63 D-017 N-036 N-035 1.36 0.15 0.15 0.15 0.15 P-015 N-037 N-036 1.23 Overtop Overtop Overtop Overtop D-018 N-039 N-037 1.20 Overtop Overtop Overtop Overtop D-019 N-040 N-039 1.19 Overtop Overtop Overtop Overtop P-016 N-041 N-040 0.61 Overtop Overtop Overtop Overtop D-020 N-043 N-041 0.86 0.15 0.15 0.15 0.15 D-021 N-044 N-043 1.67 0.96 0.96 0.96 0.96 ... • ... ... SCM.£ 1M n:ET LEGEND C CQtCh BQs(n PS Pipe ID !10-YeQI" ! Flooding Retul"n Pel"locl ·.~, f' ; :; • .I ,, 'j_ ---·~ ~ ·--------. •, Pl61, " "1 1 P15 1;~ . P14i'.1' , .• ~,,, P13 ,1', l~R-YeQl" I -- ~}I I:; , !2~~y;~·--',:: !,' , .. ··.-1"_ , . ;, ,_1,'1.'.};, P9 I" · · · , · '1•, . ; .. :; (~ <'· F' ,_/ ' _, ~' -·· Ci., ,-.;..-----...I '" 1J-_ _ii· .. ~ t:.· ' :,,eA,· :: ,, , , ff, P117 ,~-Ye~~-, ',:") . ··-·---.. -· •• , ....... .I ! ,------;,.d, --- l2=cYeQI", ! i: -~j i! ,1,.,,_, I{-i Pl J: ,1~ ' · ~0-YeQl" l Haozoua Engineering CIVIL EIWUMi .._ 1£ 1161H IT, -YA -, 4111 aJ Cid/ DES1CNID El't. OATL EVENDEIJ.. PLAT ' ! UI I/If/II Flooding Locations ORAv...l SY; UI OATE· 1/12/111 PROJECT NO. FIGURE 4 " " ,.. "" 200 SCALE IN F'tET "' • '.,\; .}:;. ', \ / II , .. •· I I ',. ., ; 1 \t 'I i; '.\ ! \ -·\t "td\ \~il 11 i\f/l 'i:{\ l~ \iij ) tf ~ ,. ,, i '"',: 3,, .'f~:I ,J:1, ii 11. el w2 .°"/ i"" f~ 1.f' i\\ l-s, ~ ,.i ~ :,: ,_ ~ .., ,, ; -. V,".t•~_."',,_,),c.\",·" J '.":· .. ?"·\ ;,. ... , i i ·-.,,, .. ! ,n "' .. •-,. ,.--;-,,,..;,r,_,'-Y ,r~,~,oJ; e2 ·11 . ' · i1 i! lllt '!•,, ....... ,.~.~--' ( . .,_,_,) ·--J,.,icJ. '--~~-' .... 1, t .• \ __ ,,,_ ··,,, t··-, 1 i r .. , ,in -i i :I; \ll \ .. ,.._._ .. H··. ····,,._ ,,--,,1 "'', ....... ,._....., '\'. . D ,., , If ' n ~ ! c·•-'"'• (''····' "'--~-,., ·111. _../ 'exf?~~t" '(9.3 AC) f-i u , tr . .,""'""''" . ., W-""~' .,,,~, df .; 1•-. 'H: c~\;I e;S l-,;1 l;ifTf-t AVE.: .t 1 ·w7 \ l ,-.·· I \ ! ·I \ \ I _/ sfil IS, 1~-X ~F / .. J ,tRili\JTARY \tr.Rli:A,l ...•. i ;,-~,., ' ·. \ ;, ..::-J ' ' .,, \ rt:: .-·, ,,., ' ~ >, \ 1'\ ·. ~-\1 \ Y-·. \ \ \f '. ::./ J~-<\. '\\ ~'-~------... SITE IS ,5% OF i·, \,r'.'('''c:·· iRIBUT ARY AREA) \ .. ,\\ ' ',, . .-.,,_ .. ..,·,,. .f., .. ,,...._r,. ,'!t ' '\., ·,.~. ,·,tc\) "··· . ,~,/ "~.-,)' . "\:. ·~ •.. Haozous Engineering CIVll. EIIGll£ERIHG 14816 SE 116TH ST1 RENTON, VA 980:59 ~-2707 .......... .. ,.. 8/12/02 &Ill ........ &Ill ~,. 8/12/02 e7 f ! \. ! ,·! .~:.. . . ;~ . ""·'<-';.,·, '"/11 · SITE IS 9% OF TRIBUTARY,, A~EA i "~ ' PROJECT NO. EVENDELL PLAT RGU Drainage Basins 2 200 400 S:CALE IN rE:ET Haozous Engineering CIVIL EHGD<EERIHG 1'4816 SE 116TH ST, RENTON, \IA 98059 <125-235-2707 ..,......, ..... EVENDELL PLAT ........ """ Land Use/Cover Types I &JM I •1121·· I &JM 8/12/02 PROJECT NO. FIWRE 3 SE 144TH STREET LEVEL 3 DOWNSTREAM DRAINAGE ANALYSIS Prepared for: Mr. Dave Petrie 811 So. 273rd Ct. Des Moines, WA 98198 KBS Development 12320 NE 8th Street Suite 100 Bellevue WA 98005 Eagle Creek Land & Development, LLC 13701 SE 253rd St Kent, WA 98042 K.C. D.D.E.S. MAIN FILE COPY Prepared by: Ed McCarthy. P.E., P.S. 9957 171"' Avenue SE Renton, WI', 98059 Tel. i425) 271-5734 Fax (425) 2713432 Jun,, J 5, 2007 Acknowledgements SE 144 th Street LEVEL 3 DOWNSTREAM DRAINAGE ANALYSIS Prepared by: Ed McCarthy, P.E., P.S. 9957 171st Avenue SE Renton, WA 98059 Tel. (425) 271-5734 Fax (425) 271-3432 Prepared for: Mr. Dave Petrie 811 So. 273rd Ct. Des Moines, WA 98198 KBS Development 12320 NE 8th Street Suite 100 Bellevue WA 98005 Eagle Creek Land & Development, LLC 13701 SE 253rd St Kent, WA 98042 June 16, 2007 TABLE OF CONTENTS 1. Backgroundinfonnation ............................................................................................. 1-l 2. Hydrologic and Hydraulic Analysis of SE 144<h Street.. ............................................ 2-1 3. Drainage Mitigation Options ...................................................................................... 3-1 4. Key Results and Recommendations ............................................................................ 4-1 5. References ................................................................................................................... 5-1 LIST OF TABLES Table 1. Contributing Basins .......................................................................................... 2-4 Table 2. Peak Flow Rates at Key Locations ................................................................... 2-8 LIST OF FIGURES Figure 1. Vicinity Map .................................................................................................... 1-2 Figure 2. Study Area ....................................................................................................... 2-2 Figure 3. Soils Map ......................................................................................................... 2-3 Figure 4. Basin Map ........................................................................................................ 2-6 Figure 5. SE 144<h Street Conveyance System ............................................................... 2-9 Figure 6. Offsite Mitigation Options .............................................................................. 3-2 APPENDICES Appendix A. Photographs of the Downstream System Appendix B. KCRTS Documentation for Contributing Basins Appendix B.l KCRTS Time Series Calculations Appendix B.2 KCRTS Pond Designs Appendix B.3 KCRTS Peak Flow Rates Appendix C. XP-SWMM Model Results Appendix D. HEC-RAS Analysis of Roadway Conveyance ii 1. BACKGROUND INFORMATION This report provides an assessment of the conveyance system along SE 144th Street in the Renton Highlands area of King County, Washington (Figure I). The study area is located within a catchment of Orting Hill subbasin (Tributary 0307) of the Cedar River watershed (King County Department of Natural Resources, 1993 and 1997). The conveyance system has a contributing drainage area of 253 acres. The conveyance route is downstream from three proposed single- family residential developments that are currently under drainage review at King County DDES. These developments include Threadgill Plat, Liberty Gardens, and Cavella. This Level 3 Downstream Drainage Analysis bas been prepared at the request ofDDES. Flooding currently occurs at locations along the SE 144th Street conveyance system. Flooding has been observed at the intersection of the 162°d Avenue right-of-way and SE 144th Street (Photo No. 1 in Appendix A). In addition, King County Roads Division has recently constructed conveyance improvements at the intersection of 160th A venue SE and SE 144 th Street, presumably to collect overflow from surrounding catch basins. While the conveyance system is apparently undersized for its contributing basin, there is a surprisingly little documentation in King County's records that flooding exists or has occurred in the past along SE 144th Street. Neither the long-time owner of Alpine Nursery nor an original resident at Carolwood, that I interviewed, had observed road flooding along SE 144 1h Street over the past several years. The evaluations presented in this report are intended accomplish the following: -· • • • Delineate the conveyance network's contributing basins and quantify the flow rates draining to the conveyance network. Estimate the conveyance capacity of the system, including the 18-inch diameter pipe, northerly roadside ditch, and roadway. Identify areas of flooding . Develop conceptual drainage solutions to mitigate impacts from the proposed and future development projects. 1-1 SE 14rs1reet-June2007 ~···-~ i ,r ·/1··;::j ,,!,! '· il 1-; '11: ;-1' Vicinity Map -~.· . T I '' ! ' I ' ''i -...... ' .. ·. '\ SE 144th Street Drainage Analysis King County, Washington ' ,. I ! j ' 0 :ii ' ! 2,000 " !i Feet \'_·.~ ... r: \ \ : : ; . ·:T' Ed McCarthy, PE, PS 11957171st-.,. SE Rentoo, Washinglnn 98059 Phone: (425) 271-5734 fa,: (425) 211-3432 " "'\. \ y )\ . ) -6115/07 Figure 1 2. HYDROLOGIC AND HYDRAULIC ANALYSIS OF SE 144TH STREET 2.1 Contributing Basins In effort to develop a hydro logic model of the basins contributing to the conveyance system along SE 144'h Street, basin boundaries were delineated using the following resources: • City of Renton aerial topography ( I-meter contours) • Level I Downstream Drainage Analysis for Threadgill Plat (Baima & Holmberg, Inc. and Ed McCarthy, PE, PS. November 18, 2005) • Level I Downstream Drainage Analysis for Evendell Plat (Haozous Engineering, June 15, 2001) • Technical Information Report for Hamilton Place (Barghausen Consulting Engineers, June 2003) • Technical Information Report for Evendell Plat (Haozous Engineering, June 15, 2001) • Technical Information Report for Nichol's Plat (Haozous Engineering, May 2003) • Technical Information Report for Liberty Grove (Daley-Morrow-Poblete, Inc., February 2003) • Record drawings for stormwater design for Carolwood (May 1977) • Record drawings for stormwater design for Liberty Lane (Doneshvar and Associates, PS, June 13, 1979) • Record drawings for SE 144th Street (King County Department of Public Works, January 18, 1984) • Record drawings for 154th Place SE Slope Stabilization Project (King County Department of Public Works, June 23, 1997) • Field verification of key locations in the watershed The study area under consideration is shown in Figure 2. Cover types within the study area include those associated with relatively dense single-family residences, forest, and pasture. Soils in the watershed are mostly of the Alderwood series (Figure 3). However, a band of outwash soils (Everett series) exists along SE 1441h Street, at the southern boundary of the study basin and extends to the south. In total, an area of253 acres was calculated to drain to the conveyance system (Table I). Based on cover type estimates, about 25 percent of th.e contributing area is effective impervious surfaces. The size and boundaries of the delineated sub basins draining to the conveyance system 2-1 SE 144h Street-June 2007 Study Area SE 144th Street Drainage Analysis () 400 ....._ ____ ~I Feet King County, Washingto n Ed McCarthy, PE, PS 995 7 171st Avenue SE Renton . Wash ington 98059 Phone: Fax: (425) 271,573 4 (425) 271-3432 Date: 6/15/07 Figure 2 'i J ~' 1: 'I I, ,, ,, ' ,Ii ,", . I .. L. kl i ! I 1t31ni,•' ' :I· '''.,1~, ii .1~th I I @C~~( 11·· '!·n1 [ ... -: l -/ J;;..r' i ~~:~. ·.lllj i ; i ,i --... :. : -I 'I ,-· . i ! it 136th. ' .;(' i11 ~.' ·'.I. l' I A ( ... ' 1?Jtl( -r ·w,-.· ~-;, i .!' i, __ _i. Soils Map ~, Drainage Analysis 1,000 SE 144th Street King County' Washington Feet 1 · ,· Ed McCarthy' PE, PS 9357 171st Avartl6 SE W8oliing(Dll 98059 Rsnfoo, =, Phone; (425) 211-,._ Fa>c (425) 211-3432 : ' ,! ;L !£1: ., I a,; '(DI [T"1 'i I I .. ~I , I 11 '132n~ ·I 13Bth~ :e I 1:- I ; I~ :~· ~ 5/03/07 / ·'-- Figure 3 Table 1. Contributing Basins Basin Till Till Till Outwash Outwash Outwash ID Forest Pasture Grass Forest Pasture Grass Impervious Total AC AC AC AC AC AC AC AC 10 -0.16 0.29 0.08 0.53 20 -0.30 1.05 0.51 1.86 30 -0.31 0.91 0.41 1.62 40 0.26 0.30 0.56 42 -0.03 0.96 0.67 1.66 44 0.99 0.99 50 0.51 0.51 52 -0.01 0.80 -0.01 0.80 1.15 2.77 54 0.03 0.03 0.83 0.04 0.04 1.24 1.44 3.64 60 0.52 0.52 70 -0.51 1.70 -0.34 1.13 1.34 5.04 80 5.28 0.12 4.35 0.59 0.01 0.48 3.40 14.23 90 0.40 0.40 100 0.45 0.33 0.61 0.17 1.56 106 2.50 0.12 3.34 0.12 3.34 4.64 14.05 110 6.43 12.24 12.33 7.10 38.10 120 0.58 1.00 1.58 130 2.49 7.12 5.80 1.58 16.99 200 4.45 0.14 1.79 1.18 7.56 210 3.31 1.70 4.60 2.93 12.55 220 1.56 1.90 3.46 230 3.95 5.71 9.66 232 1.38 ---1.38 240 3.65 4.48 8.13 241 0.23 2.99 3.68 6.90 244 0.71 11.46 10.75 4.68 27.60 250 -0.17 4.66 3.23 8.06 260 2.33 1.74 4.07 270 --2.22 1.60 3.82 300 9.47 1.73 4.13 1.56 16.89 304 2.12 1.36 5.73 3.74 12.95 306 1.25 0.15 0.28 0.08 1.75 310 9.32 ---9.32 320 8.92 0.18 0.33 0.09 9.52 330 1.37 0.34 0.62 0.17 2.50 59.71 42.22 75.40 0.63 1.32 10.47 62.98 252.73 Effective Impervious = 25% 2-4 SE 144'n Street-June 2007 were driven by the locations of catch points and the watershed's topography. A total of 35 subbasins were delineated (Figure 4). Recent higher density single-family developments contributing to the conveyance system include Hamilton Place (Catchment C-260), Evendel! Plat (Catchment C-230), Nichols Place (Catchment C-220), and Liberty Grove (Catchments C-240 and 241). The attenuation provided by the stormwater ponds for these developments was included in the hydrologic model of the basin. In addition, the stormwater pond for Carolwood (Catchment C-106) infiltrates runoff for at least up to the I DO-year event. Record drawings were also obtained for Serena Park (Catchments C-70 and C-80) and for Liberty Lane (Catchment C-330) but these older pipe detention systems from the late 1970's do not provide substantial detention volume and were not included in the hydrology model of the basin. Record drawings for the conveyance system along SE 144th Street (King County Department of Public Works, January 18, 1984) were found to be accurate when checked against field observations and a recent field survey. The drawings show that the 18-inch diameter CMP is perforated in the upper half of the pipe. According to the plans, the pipe is set in a gravel bed to allow infiltration. This design encourages infiltration and groundwater recharge by talcing advantage of the relatively flat pipe slope and surrounding outwash soils. While this pipe configuration provides baseflow benefits to down gradient tributaries of the Cedar River, the perforations do not provide much flood relief during large flows. Assuming a reasonable infiltration rate of 10 inches per hour, and a 42-inch wide infiltration surface that extends from 162°d Avenue SE to !56'h Avenue SE, the rate of water infiltrating from the pipe to the native soil would be roughly 1.5 cubic foot per second. This rate is small relative to the predicted I DO- year flow rate of almost 40 cubic feet per second. While the infiltration component of the conveyance system has been noted, it was not included in the hydraulic model of the system. 2.2 Hydrology Assessment of Contributing Basins The hydro logic model KCRTS was used to develop runoff time series for each of the basins contributing to the SE 144th Street Conveyance system (Appendix B.1). The reduced I-hour KCRTS time series data set was used for the Seatac rainfall region with a correction factor of 1.0. The I-hour time series is appropriate for the modeling conducted because flows from a sizeable portion of the basin are routed through detention ponds. In addition, the KCRTS modeling methodology neglects attenuation that occurs when time series are routed through the watershed. Time series routing through stormwater ponds was conducted to characterize the attenuation provided by some of the more significant storage areas in the basin, including the stormwater detention system for Hamilton Place (Catchment C-260), Evendell Plat (Catchment C-230), Nichols Place (Catchment C-220), and Liberty Grove (Catchments C-240 and 241). ln addition, the infiltration stormwater pond for Carolwood was assumed to infiltrate all runoff from 2-5 SE 144'1'Streer-June2007 Drainage Analysis King County, Washington 0 400 .__ __ ~Feet Legend CJ RID C.~:.=:J Basin Boundary o Type 2 CB o Type 1 CB -Pipe/Culvert Ed McCarthy, PE, PS Date: 6/15/07 9957 171st Avenue SE Renton, Washingtoo 980S9 Phone: (425) 271-5734 Fax: {425) 271·3432 Figure 4 Catchment C-106. The stage-storage relationships for these stormwater ponds are listed in Appendix B.2. Peak flow rates for the 25-year and 100-year return periods at key locations in the watershed and along SE 144th Street are shown in Figure 4. The peak rates associated with the 2-, 10-, 25-, and I 00-year return periods at these same locations are listed in Table 2. The major inflow points to the SE 144th Street conveyance system are at the intersections of 162nd Avenue SE and 156th Avenue SE. A total 100-year flow rate of39.72 cubic feet per second was predicted to flow to SE 144th Street from contributing basins. 2.3 Hydraulic Analysis of Conveyance System The conveyance system along SE 1441h Street consists primarily of an 18-inch diameter CMP located along the south side of the road. A ditch and culvert system is located on the north side of the road. The ditch and culvert system is not continuous along the entire length of SE 144th Street. Rather, it is broken up by segments of road with no conveyance on the north side of the road. The northerly ditch and culverts are connected to the 18-inch diameter storm pipe by 12- inch diameter cross culverts at four locations along the conveyance route. At 1561h Avenue SE (CB-6), the diameter of the pipe system increase to 24 inches. From CB 6, the pipe system continues west in the unimproved SE l 44'h Street right-of-way. At CB I, the pipe is conveyed down a steep embankment to 154th Place SE and then to an HDPE tightline down the steep ravine slope to Tributary 0307 (King County Department of Public Works, June 23, 1997). A detailed field survey of the entire pipe and ditch network, including several road sections, was conducted by Barghausen Consulting Engineers (June 2007). These data were used to construct the XP-Storm and REC-RAS models described below. The hydraulic model XP-Stonn (Version 9) was used to evaluate the 18-inch diameter pipe conveyance system along the south side of SE 1441h Street. The EXTRAN layer of the model was utilized, basing hydrologic inputs on flow rates predicted by KCRTS. The XP-Storm Hydraulics engine solves the complete St. Venant dynamic flow equations for gradually varied, one dimensional, unsteady flow throughout the drainage network. The calculation accurately models backwater effects, flow reversal, surcharging, and pressure flow. The model allows for looped networks, multiple outfalls and accounts for storage in conduits. The XP-Storm model accounts for pipe friction losses and pipe entrance and exit losses. A Manning's roughness coefficient of0.024 was assumed in the modeling for CMP and a value of 0.012 was assumed for concrete and plastic pipe. An entrance coefficient of0.5 and an exit coefficient of 1.0 were used at catch basin junction. XP-Storm modeling results for the 25-year peak flow rate for the conveyance pipe along SE 144'h Street is provided in Appendix C. 2-7 SE 144°' Street-June 2007 Table 2. Peak Flow Rates at Key Locations Location Return Period (Years) 2-Yr (CFS) 10-Yr (CFS) 25-Yr (CFS) 100-Yr (CFS) CB-18A 9.86 15.70 19.08 24.66 160m Ave SE I 1.23 17.65 21.31 27.42 CB-5 11.72 18.37 22.23 28.52 CB-4C 4.25 6.86 8.36 10.86 CB-4 16.09 25.43 30.85 39.72 The hydraulic model HBC-RAS was used to model the roadway surface and ditch conveyance under flood conditions for the I 00-year peak flow rate. The 100-year peak rate assumes that 5 cubic feet per second is conveyed in the 18-inch diameter storm pipe along the south side of the road. The remaioder of the flow is assumed to be conveyed io the roadway and roadside ditch. The roadway conveyance capacity was evaluated from CB-1 lA (HBC-RAS Sta o+OO) to the iotersection of 162nd Avenue SE (HEC-RAS Sta lo+IO). HBC-RAS analysis of the roadwa)' conveyance system for the JOO-year peak rate indicates that the ditch system between 162n Avenue SE and 160th Avenue SE has adequate capacity to convey the 100-year peak rate. However, driveway culverts along this reach would be overtopped. In addition, the HEC-RAS model predicted that flow depths would be up to 0. 7-foot deep over driveways. HBC-RAS results are presented in Appendix D. Roadway flooding along SE 144th Street would be considered as "severe roadway flooding problem" according to Kiog Couoty standards (King Couoty Department of Natural Resources, January 2005) due to the following conditions: • Between the intersection of 162nd Avenue SE and 160th Avenue SE driveway culverts along the ditch on the north side of SE 144th Street'would become overtopped, posing a threat ofuosafe access due to indiscernible driveway edges. • Floodwater over the driveways on the north side of SE 144th Street between 160th Avenue SE and CB-I IA would be deeper than 0.5 foot, posing a severe impediment to emergency vehicle access. 2.4 Flooding Locations and Flood Flow Paths Flows with return periods of 2 to 5 years likely surcharge the 18-inch diameter pipe system. Flows were predicted to leave the pipe and ditch drainage system at a number oflocations including CB-4C, CB-IOA, CBl4A, CB-ISA, CB-ISA-1, and CB-18A. Between the intersection of l 62"d A venue SE and 160th A venue SE, overflow from the catch basins is conveyed to the west in the roadside ditch on the north side of the road. From the intersection at 160th A venue SE, overflow from the catch basins is conveyed to the west maioly along the north side of the road. Flooding covers the north half of the north travel lane at locations near CB-I I A. From CB- I IA, floodwater is conveyed further west in the north travel lane uotil it reaches a low lyiog area located north of CB-9A. Depending upon the magnitude of flows, the floodwater either 2-8 SE f4,f~ Street-June 2007 1-,, --.1 ./ ' I I ! I I I I I I I I ' I ' .J I ~ l \ I .. j -----L L_ '-l-._ . ·, I I'~-i . I ' C Legend 1 1 1/ / r-· / · 1 T-1-, -i-i-1-1 I J \\ \\ l'/k 1 .1 ' IH / '1' -1' I I I I I I \ : , , I I I · I :,, .111--' _I _L. I '! '·--r-----T-·--1 \-\\ I C-300 I Ii I I I I \ \ . I··. I· I L -I J \ \ -- 1 --1 / f I C-"' 1 I ~~ i I . . I i \ \. I , D Type 1 CB I j f f /----',--·-. LJ _ _j 1J c-210 ll \ '··, ... , JI I 12-18" Pipe/Culvert -L._ I / I [ -1 .' I -\ . ..;.. ··,. '··+. t------- 24" Pipe/Culvert . ,-. / 1 I / ~ -··-···-·,. I f ~I -.. _ .G ..... , I 1. ·' '. 1 .~1. ··,··,·, .. '\ .··,\ . / 1 1· r . o,. \ \ · · I '° , · . CJ R/0 r--------; i i L·-···-·' Basin Boundary ~ Flood Flow Path 0 Type 2 CB I C-10 I Basin ID ' j "' .s m Cl It) I!.! ~ Cl ii: .IN I;; :ii ,.!. ,.!. ~~ NN in G' NN ~~ ~ 5 " o' ,1' wj .,~ ~i ~ ~ '--.---.---· . ·. w I ·· · ~ 1 \ \ I ----c.. ~ . i ~. r· -+--r-+-,-·-· r1-I \ \ \,. A._ 1,11~ I' ··1 I . \ ~', "·· I / ·"' r j . , \ r \ . ""' • . "' ' \ i .-' \ j . I I • I I I ' ~·-· ··-·-·-~ . i i ·--1. ~ I \' ./ I .· I ' ~ . i I I . ~ --·-'·--------7~. . '. ~ ii 3i !;: C ~ .e I I I _,~---1 I , l' . .J ... -·-------,,,.,,,,,./ ------·-/ ///!/ If ,. .• I I l . :, : I . r I ' (/, .'.'. ''''.' ; 'I•![ 'f.;_ i1fi1; ' \ ·I' . : I:.·' I \ ' }f\,. ' I I \ I I ! I ....-\ I ·. ' •• I / I ·I ,. .. -, . , . --? I . . / ! I i \' ~ -----• ~ ' y ·, ...........-1·-/J j' ! _..J...--_.....,. -. I i .·· ·---.. ---· . ' ·. -, ·-· ---· .· --, C-44 l.--.....--1 I.,, i 10··' i I I·/···. ,' ' I . I! I . I I I. I ' i / /// / / / ! i / I ' } I 1 ~,oo / I I / / 1 I 1 • , CB-48 . C . I I I ~--',/ ··~ I i .~,.-,----,--,-----;cc====~~ I I I CS-1 CB-2 ' [LI,-'' I \ Jf},,'.i/cf-i > ,:,;1y., . ':'. CtA \ ir· I I . Likely Flood Area , / , and Flowpath L I I l $Fi I \ \ \ i I -.'. / ., . \ I / ~ -. . "\ I ,.. \. I . i ,/ 0 0 N ~i .... Cl) if ···1~ ·.<:·· ·1 ~ " ~ •I \J ,;::·•·-···-·· ···-··· I \ ----------=,,.··=--~.......::.:.---\ CB-3 ·\! l . ~., ---c--,1 • ·. . ff 1. // )c~~ 11cr-' -.. l r11· .. mi I i . · · E .!!! ~ "1 \ /I '?ilf~ 1 ~r irr,1 1 . I I I IJ---/1-- 1 L / r I I • I j ~/ --'-- CB-18A CII "' -.i?:-UI m >, C C: "' <( 0 CII Cl) 0) C) C: · -···-r·-··-r· · · · ·-··-,"=··;-···-···-··· -c::;.. ·,· ·i1-·=··· ··.-···-···-···-···-·-··· · ::! .~ ~ . jcB-··.1 ... ·,r. c,, 1 ;. B-1_ CB-16 C-50. ',I ICB-17 'CB-18. \ . / B-111; ~ c5 ~- I · r s lt4thst,/ ·/ r---, . 1 ; . 1 > z:. ' 1 · : I I · ,·· I . /'•"-~ / 6 c: I· I 1· ~ f I ' I '•y( 0_"1 ·. 0 al 8 I ' ·/;: / " '·-~,>,,,ef .. ~ C) .· .1, I / /· •• ~ · • U) -c: · I I·-". W._ ,· I / I : " ' ~ I'· I / .'/ I_/' /"-. i \ = = -"----1' f-/"' ' ', \ i ;g: / ,I / ' ) ~~ I / I /-,. Ww r------1 ' / "' I i : I I / infiltrates at this location outside the road right-of-way or continues to flow to the Carol wood infiltration pond. Flows larger than approximately 10 to 15 cubic feet per second likely do not reach beyond CB 5 (located at the intersection of 160th Avenue SE and SE 144th Street), within either the pipe or roadway. 2-10 SE 14(" Street-June 2007 3. DRAINAGE MITIGATION OPTIONS The following four concepts were developed to mitigate for the proposed developments' impacts of downstream flooding: • Providing onsite detention to King County Level 3 flow control standards • Providing offsite conveyance system upgrades (Offsite Option I) • Providing offsite conveyance system upgrades and infiltration (Offsite Option 2) • Providing offsite conveyance system upgrades and infiltration by implementing bioretention (Offsite Option 3) 3.1 Onsite Level 3 Detention Level 2 stormwater detention standards are required for the Threadgill, Liberty Gardens, and Cavella developments. When downstream severe roadway flooding is of concern, Level 3 stormwater detention standards are often included in the drainage design for new development as a stormwater mitigation. Providing this type of mitigation has been used with success on several projects in King County. Level 3 detention standards would likely adequately mitigate the impacts of flooding from the proposed projects on downstream flooding. Adequately mitigating the flooding problem, at minimum, requires that runoff from the projects not aggravate the existing level or duration of flooding nor create new flooding. Adopting this strategy as a mitigation has several advantages that appeal to developers. Because the mitigation is entirely onsite, the developer has control of its design and implementation. No easements, consents, or coordination with downstream property owners is required. The mitigation is typically easy to implement because it is simply a matter of enlarging the already proposed Level 2 stormwater facility. This type of mitigation particularly makes sense where the proposed development is small relative to the surrounding basin and the required downstream upgrades are either logistically difficult or overly expensive to implement. The main disadvantage to providing Level 3 detention as a flooding mitigation is that while existing problems are typically not aggravated, the problems are not solved either. 3.2 Offsite Conveyance Improvements Offsite mitigation Option I would include improving the conveyance system along the north side of SE J44<h Street (Figure 6). Between 162"d Avenue SE and 160th Avenue SE this would entail upsizing driveway culverts and re-grading and cleaning open sections of the existing roadside ditch. From 160th Avenue SE to 156th Avenue SE, a distance of about 1,300 feet, an 18-inch diameter storm pipe would be constructed to increase conveyance capacity. 3-1 ~-,-~~~-~,,--:c::-~-=--11 ! \ I ' -' ' ,------71 "'-I I i i '•., I _,F ~---" •:, --! 1---' -j/-1 i i I ! i ! I I I / 1 I--:'--;·\~--! \ ·1 k----t I I , ! 1 , . I I I 1 / • I • ·----~. j IY_:_ Option 1 -Conveyance .--_ 13~-9 r, [-es=-1el---_J ____ j __ L_ __ ,' i~ ____ L ___ L __ J _____ 1~,/// 1 I I ! ·,\\ -·1 l~ ;· / / ------'I --~------~ J !!l I / · ,/ . ..i (,-·-------------i--·----r---,-------,-r------r---"', / 1 I Jj f /' .;'· I ----~ I I ' I I i I I ---', I L ' !<( I / -~ I i I I : i I I I ' L. ----, j-g J // cs:iA ·@ L ·1-__L 1 ______ l_ __ /_ __:_r----/---,L __ I_ -~ 18" Conveyance ----_, --_\ ~~~~~~~~ert ! jr:' /i: I -/ ' -i I Pipe -'----. : ' I' j ,: i i I : ' I ' ' I I i i I '' (o: I I I : i I _J ' I ' I i: 1 I ·, 1-r 1 ! 1 1 1 1 s-110 : cs-1sA1 1 -1 -- 1 1 I ' I CB-11 C ' --1 , ' i ' _ ------- 1 1 -~----'-----'-------~----'------·--6----<---CB-18A _____ _ -~:j~~~~~----~--~~-\~-~--T--7--~I c;J---~ --==---=-.=:::=-___ -::_-:-~-.--~=:_::_-~--,-------: __ :,-----,-,a ~-._ ,,-·-.:..-_-::__--=-------= ~~, -=~~~=---__ "T -- ' }ii_,t_i_,~'_) ~"il.'c,t. - 1 1 d ---1 1 '1 I I -cs-al ----1es:'f) C :g-----~-i\ ·"? cs-~------1-_-_-cs-10'-', -rcs,1rfj csr'12 __ lcs:1 CB-1~/ s:1T:'· CB-16 SE 144th sJ '1 1 W::9.17 /CB-fB, ', /\ ,B-1'9 ;'° -•--.•,,w-c\\: ''" 'V J -1 ' ---' -' -' · 1 ,-L~/ l ,j V f: >:,~'~/~\~\:ii< , ~,~~~ /'----,,,, i --~ -X ( / i I I ---I'-·"! -, \/J ___ / I ----·r'---.,_. \ \ \: ,-, I ) \ \ / /:: '\ ~ -'s::-;,:,,,~v'·'·>®,\--1~\0\\ '--_,\, • ...__ 1 \.,_ -------I 1 · -, / I ' · i ' I I ,-...._ ' --_.\---• l --,·>\~'\{AZ>"~ I~-,,:;"(-,-I -,_ --I " -r -' ' ' c--------" -----c·-r---------------I -\_r, ' ' ~ --I -I I ' ·---J ,:~'\\~:i&"\zJ\\tl\ _ \. 0 --------------~"c-_;_____J_ i ; / :·j i , : ,:---_/ / ' , I -1 ' 'i · -- 1 ' -. ----tJi,%,\-._--_,1.~\0.::<8.:fr.~,'-\,'-.. 0ri:%s{,::k~ --.... _ )( 1 ------c::i. , .~~\:.~ '-, ,,.:,:,\_,--.. <-~~: ~--,'\ ;;.\,,'~-', r//~ /1~'.-71 ; r~:::: l. _1_: _.::, i -,~-L CB41, -eB=-1€"' ------l I -=7,-,:-=--r--r----,---r---·-~ ---·---.. _/ '-..._______ ____ L_~ _J____ _:' __J / -~ , - L -------,------~--------------</ I _ _ !' 1 1 1 ---~ i 1 -l I /r-----~--,-------.. .-1 --_________ { I L1 · _--\ ___ 1·j,lli / -I I ,__ w~ I , , ---~:i___ ;en, , - ,"._ -~, ~ !~1" I I 1·1 -I I (/) ' I ' I . " . 1 !IV . I ., :,;-,,,,---;,,-Jr,,o·,__..,· ~_J I / nrtrat,on _ I \_ i'" , I ___ , __ , _,,,;;:-I ' pct tt> -· I', ,-JC: / I I / ----, on :, --I ,., -· I I 12" Overflow , ---,---18" Conveyance If -------i '---..._,,)-'-v------~ ---J .µ.= // Option 2 -Conveyance/Infiltration 1\ -, '\ "iT' i \ ' '\" \1 .if"'('' '('-IJ cl_ CB-2 L Prpe I . 1 [ Pipe <( I I I ro _/ ' I r.R-1'lA.1 -I I I i ·'('.f .>" CB-3 "~' '~'01\,, ~\i~.J~'\;\ft\,·.-, ·.:,,\'\\·' r ·~1~'\ ,~'~-'~--__.' ~'1{1\, ---\,·--,--=~~ --! I I -§ ,~-rl I Ditch/Culvert ~ 1 t/ ->I , c, -~-~----' cB-,SA """"""' , 1· -~ ==--, l UB-18A -------1 r-----,-,,-r >,~_.~'--~-~~,,~~~\ __ J'I~'-\ '\\,~~'\'!\.~-~"' ,~, »~ .. , \:-,0:~--~,I%0~-j \~ §,:;~,~)%,\\-_; \ -• 1 1 c_ _ _ __ I ' --· I -L.:JF -1 I · 'i ( ---1 ~ • -------' ' --P ~-( '--/ -S'--"--'--------'L..._~-,--\ \ I I / -,, ~ I I -----' ' ---\f\ ' 'i ' ,----' ' J '' / ' 1---/\ ---/,..,.~'--... ' ~~· ..... , -~ ' ~ I " --I I, '"" ' ' ", V xf'-i ___JI , , i / / '-1 --, \_. -.• --------' I ' ' '1 _ ' \.___ I 1 :, • ;_-__ --,J-~~-'c--r-1 -~r~~k J ,.._ -----L , , • . ·, , k'===1-,:::==='===kh=1 -I?-·- /,/ --,/ ~7 :,. I I • 0, \ Option 3 -Bioretention I -I -! I I , -~, """'TAI -[ -I _ 1 I i j i ---._ / [ J -! i • i n~~~T1 t_. _ ) ~-/ ! c:r·~~~c.J CB-2 J CB-3 £ 1 U) --~ CB-I -I )i \ ·, I I .---.___ 1-'" -~ ? ~- ;,: -:, r.R \ " _____ _:_, ~~ ~,.._~~'if;: -!< ~ "j tV-/., : \.L _~_'Tr\~-~--I fl //' - ·-~ !<( ,/ i· ,'C_ -rr .. _ -_i_ !ff··/ > -,: ~~ -_ 1 11 _ i,/ Q - <!:! tEi-110 ~11C ~. CB-15A- ~-1 p ~~G = ~-----!f 9B-18A -- ,~,-~~.-.~-~11•11\ rs~,r==:1--~--J ~-·1 r cr · -=lcg:7 _T '~1':r"~1_1:~})~,r\r ~*s:v .'.;:__~-.,:.____, \ mt," /-., ' ' -, --. ---\ I -, -\ ' 1 ,-I ' ' "-"· --,,~-."" '' ,~,-_, ~ §\!/,,~~-' --.-' -cc-' \ ', ' I i/ ~·111 --' ' I I \ --'-------------/.' I ' / ( ' ' '·--' ~---,11 I ' -1· \I\ 1 . ~' '· -I":,! .-< -I • ,../1j \ I --,.~, CB-r.1r'·t-1 /~B-16 I \ I f'--..... \ -...... ----...., ' \ ,s __ 1 E 1:l4thSt\[ i?cs-17 /~s-~ , 1 , 1 , --I !I_J ~-f· rr' -; I r, / I ---~:19 7 " ~ "' ~ rn 0 • (l) Q) ... :, -~ u. ;,; ::: C; ;,; .,.:. .,.:. " " NN ~~ '!!,::'!- ~ >( tu::_ !1l w~ en= ~2 C ~ • C ~~ Ei ~ <::.- " " ~& cu Cl) LL ~ 0 0 (\J L_ [ u, .~ C: ~ 0 ro ·-C: -<( Q, " Qg' c: _e; o e --0 -ctl C) ·-== -:E ~ Q) iii ~£ Ul -st .... .,, .... ~ Qw (/) C: _g Cl C: :i: "' "' ~ ii, C: :, 0 u Cl ,e, ,,: Similar to the pipe system on the south side of the road, the possibility of including sections of perforated pipe embedded in drain rock on the north side of the road should be investigated. Issues such as the impact of infiltrated water on the structural integrity of the road base and surrounding properties should be evaluated by a geotechnical engineer. 3.3 Offsite Conveyance Improvements/Infiltration As with Option 1, offsite mitigation Option 2 would include improving the conveyance system along the north side of SE 144th Street. Between 162nd Avenue SE and 160th Avenue SE this would entail upsizing driveway culverts and re-grading and cleaning open sections of the existing roadside ditch. From 160'h Avenue SE, an 18-inch diameter storm pipe would be constructed to convey stormwater to an infiltration pond located about 600 feet west of l 60'h Avenue SE. An overflow structure from the pond would tie into the existing 18-inch diameter storm pipe on the south side of SE 144th Street. The proposed location of the infiltration pond is a large lot with a smaller single-family residential structure on it. The lot could perhaps be subdivided with the vacant tract being purchased by the County. The pond site is likely within the current flood flow path oflarger storms (Figure 5). The infiltration characteristics of the pond site are likely favorable, as has been noted with the successful operation of the pond at Carolwood for several years. The infiltration pond would take advantage of the high infiltration rates of the underlying outwash soils and would reduce the flow rates to the storm pipe downstream from the pond. Environmental benefits of the system would include improving water quality and increasing groundwater recharge to the benefit of down gradient tributaries of the Cedar River. 3.4 Bioretention along SE 144•h Street Offsite mitigation Option 3 would entail constructing bioretention swales within the right-of-way along the north side of SE 144th Street (Figure 6). Bioretention is a commonly applied low impact development (LID) strategy that has also been used with great success in improving roadway drainage in established neighborhoods. Seattle's Soft Edge Alternative streets (SEA- streets) have been shown to substantially reduce stormwater runoff and improve neighborhood aesthetics. To manage stormwater runoff along SE 144th Street, a series of bioretention cells would be constructed in place of the existing northerly ditch and culvert system. Each bioretention system would be configured with an engineered soil media, a gravel infiltration trench, an overflow control, and a conveyance pipe/driveway culvert linking the cells together. In addition, each cell would be landscape with native plants. The bioretention cells would take advantage of the high infiltration rates of the underlying outwash soils and would also increase conveyance capacity for higher flow rates. Environmental benefits of the system would include improving water quality and increasing groundwater 3-3 SE 14,l' Street-June 2007 recharge to the benefit of down gradient tributaries of the Cedar River. In addition, the bioretention cells would improve the aesthetics of the neighborhood and also provide shade. Disadvantages of the bioretention system would include disrupting existing landscaping of property owners and reducing street parking. 3-4 SE 14.f' Streel -June 2007 4. KEY RESULTS AND RECOMMENDATIONS 4.1 Key Results The following conclusions cau be drawn based on the hydrologic and hydraulic analysis conducted for the conveyance system along SE 144th Street presented in the preceding sections of this report: • The three proposed developments (Threadgill Plat, Liberty Gardens, and Cavella) collectively represent IO percent of the study area basin. • While calculations presented in this report suggest that the conveyance system along SE 1441h Street is undersized, there are no drainage complaints on record that support this. Physical evidence of flooding has been documented at the intersection of 162nd Avenue SE and SE 144'\ Drainage improvements have also recently been constructed by King County Roads Division at the intersection of 1601h Avenue SE and SE 144th Street, likely in attempt to collect overflow from the catch basins at that location. • The 18-inch diameter pipe along SE 144th Street has a capacity of 4 to 6 cubic feet per second. The roadway and ditch system along the north side of the road convey the majority of higher flows. • HEC-RAS analysis of the roadway conveyance system for the JOO-year peak rate indicates that the ditch system between 162nd Avenue SE and 160th Avenue SE has adequate capacity to convey the JOO-year peak rate. However, driveway culverts along this reach would be overtopped. • Flows with return periods of2 to 5 years likely surcharge the 18-inch diameter pipe system and flood the intersection of 160'h Avenue SE and SE 144 1h Street. Overflow from the catch basins is likely conveyed in the roadway until it reaches a low lying area located north of CB 9. Depending upon the magnitude of flows, the floodwater either infiltrates at this location outside the road right-of-way or continues to flow to the Carolwood infiltration pond. • Four flood mitigation concepts were presented and discussed including increased onsite detention and three offsite mitigation options. 4.2 Recommendations Any one of the four proposed drainage mitigations would adequately meet the intent of the King County Surface Water Design Manual (January 2005) Core Requirements. Offsite mitigation Options 2 and 3 would provide the most benefit to the downstream system in terms of stormwater management and environmental advantages. While onsite stormwater mitigation would perhaps the easiest and least expensive option to implement, the downstream flooding problem would not be solved. 4-1 SE 144~ Street-June 2007 Implementing the offsite mitigations would require King County's leadership, and even ownership of the project. This would be especially true for offsite Options 2 and 3, where a vacant parcel would need to be acquired (for Option 2) or the right-of-way would need to be substantially re-graded (for Option 3). For any of the offsite options to be adopted, the County would need to see value in solving drainage problems along SE 144th Street and in the environmental benefits provided by these designs. Providing bioretention through SEA-streets and the like, to solve existing and potential future drainage problems, should be a consideration for the County. To my knowledge, the County has not implemented a project similar to Option 3, and this would be a suitably-scaled pilot project. For these offsite options to be implemented, each developer would likely make a fair and reasonable contribution to the project. The County would be responsible for designing and implementing the project. 4-2 SE 144"' Street -June. 2007 5. REFERENCES Baima & Holmberg, Inc. and Ed McCarthy, PE, PS. November 18, 2005. Level 1 Downstream Drainage Analysis for Threadgill Plat. Issaquah, Wash. Barghauseu Consulting Engineers, June 2003. Hamilton Place -Technical lnfonnation Report. Kent, Wash. Daley-Morrow-Poblete, Inc., February 2003. Liberty Grove -Technical lnfonnation Report. French, Richard, H., 1985. Open-Channel Hydraulics. McGraw-Hill Book Company. New York. Haozous Engineering, PS. May 2003. Nichol's Place -Preliminary Technical lnfonnation Report. Mukilteo, Wash. Haozous Engineering, PS. June 15, 2001. Evende/1 Plat-Preliminary Technical Information Report. ODES File No. L98P0047. Renton, Wash. King County Department of Natural Resources, 1997. Lower Cedar River Basin and Nonpoint Pollution Action Plan. Seattle. King County Department of Natural Resources, 1993. Current & Future Conditions Report for the Cedar River. Seattle. King County Department of Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio. Seattle. King Counz Department of Public Works, January 18, 1984. SE 144th Street -l 56'h Ave. SE to 164 1 Pl SE. Sheets I -8. Seattle. King County Department of Public Works, June 23, 1997.154'h Place SE Slope Stabilization Project. Sheets I -13. Seattle. King County Department of Natural Resources, January 2005. King County Swface Water Design Manual. Seattle. U.S. Department of Agriculture, Soil Conservation Service, 1973. Soil Survey of King County Area, Washington. 5-1 SE 144n Street-June 2007 Appendices Appendix A. Photographs of the Downstream System Appendix B. KCRTS Documentation for Contributing Basins Appendix C. XP-SWMM Model Results Appendix D. HEC-RAS Analysis of Roadway Conveyance SE 14.f" Street-June 2007 Appendix A. Photographs of the Downstream System SE J 4¢1< Street -June Z007 Appendix A: Photos of the Downstream System Y Photo Number I Y Photo Number 2 Date of Photo: 1-11-06 (Source: Dave Petrie) Date of Photo: 1-21-06 (Source: Dave Petrie) Location: South of CB 18A, lookinl!; north. Location: North of CB 18A, lookini, south. Description: Overflowing pond during height of rainstorm. Description: Pond north of SE 144"' Street within the 162= Water is flowing to the roadside ditch on the north side of SE 144th Street. right-of-way during a light storm. Appendix B. KCRTS Documentation for Contributing Basins Appendix B.1 KCRTS Time Series Calculations Appendix B.2 KCRTS Pond Designs Appendix B.3 KCRTS Peak Flow Rates B-1 SE 144'1' Street-June 2007 Appendix B.1. KCRTS Time Series Calculations KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-10.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STOP60H.rnf Outwash Pasture 0.16 acres Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 0.29 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.08 acres Total Area 0.53 acres Peak Discharge: 0.071 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-10.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow ·Frequency Analysis Loading Stage/Discharge curve:c-10.tsf LogPearson III Coefficients Time Series File:c-10.tsf Project Location:Sea-Tac Mean--1.641 StdDev=a 0.141 Skew-1.196 Frequencies & Peaks saved to File:c-10.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-10.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-10.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series B-2 SE 144'1' Street-June 2007 Project Location : Sea-Tac Computing Series c-20.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Outwash Pasture Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.30 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 1.05 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 0.51 acres Total Area 1.86 acres Peak Discharge: 0.331 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-20.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-20.tsf LogPearson III Coefficients Time Series File:c-20.tsf Project Location:Sea-Tac Mean= -0.857 StdDev= 0.119 Skew= 0.941 Frequencies & Peaks saved to File:c-20.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-20.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-20.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command Project Location: CREATE a new Time Series Production of Runoff Time Series Sea-Tac Computing Series Regional Scale Factor: c-30.tsf 1.00 Data Type: Historic Creating Hourly Time Series File Outwash Pasture Loading Time Series File:C:\KC_SWDMIKC DATA\STOP60H.rnf 0.31 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STOG60H.rnf B-3 SE !44'h Srreer -June 2007 Outwash Grass Impervious 0.91 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.41 acres Total Area 1.63 acres Peak Discharge: 0.276 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-30.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Cormnand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-30.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-30.tsf Project Location:Sea-Tac Mean--0.949 StdDev-0.121 Skew-0.973 Frequencies & Peaks saved to File:c-30.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-30.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-30.dur Project Location : Computing Series Regional Scale Factor: Analysis Tools Cormnand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production Sea-Tac c-40.tsf 1.00 of Runoff Time Series Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf Outwash Grass 0.26 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STEI60H.rnf Impervious 0.30 acres Total Area 0.56 acres Peak Discharge: 0.145 CFS at 16:00 on Mar 3 in 1950 SE J 4¢" Street-June 2007 Storing Time Series File:c-40.tsf Time Series Computed KCRTS Command B-4 Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-40.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-40.tsf Project Location:Sea-Tac Mean--1.104 StdDev-0.105 Skew-0. 664 Frequencies & Peaks saved to File:c-40.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-40.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-40.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command Project Location : CREATE a new Time Series Production of Runoff Time Series Sea-Tac Computing Series Regional Scale Factor : c-42.tsf 1. 00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STOP6DH.rnf Outwash Pasture 0.03 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STOG6DH.rnf Outwash Grass 0.96 acres Impervious Loading Time Series File:C:\KC_SWDM\KC DATA\STEI6DH.rnf 0.67 acres Total Area 1.66 acres Peak Discharge: 0.373 CFS at 16:00 on Mar 3 in 1950 SE 14.f' Streer-June 2007 Storing Time Series File:c-42.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Conunand Compute PEAKS and Flow Frequencies B-5 Flow Frequency Analysis Loading Stage/Discharge curve:c-42.tsf LogPearson III Coefficients Time Series File:c-42.tsf Project Location:Sea-Tac Mean--0.747 StdDev-0.110 Skew-0.794 Frequencies & Peaks saved to File:c-42.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-42.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-42.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-44.tsf Regional Scale Factor: 1.00 Data Type; Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf --Impervious 0.99 acres Total Area 0.99 acres Peak Discharge: 0.408 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-44.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-44.tsf LogPearson III Coefficients Time Series File:c-44.tsf Project Location:Sea-Tac Mean--0.596 StdDev-0.096 Skew-0. 562 Frequencies & Peaks saved to File:c-44.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-44.tsf B-6 SE 144°' Street-June 20U7 Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-44.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-50.tsf Regional Scale Factor; 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf Impervious 0.51 acres Total Area 0.51 acres Peak Discharge: 0.210 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-50.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-50.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-50.tsf Project Location:Sea-Tac Mean--0.884 StdDev-0.095 Skew-0. 562 Frequencies & Peaks saved to File:c-50.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-50.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-50.dur Analysis Tools Conunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series B-7 SE 144"' Streer-June 2007 Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-52.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf -- Till Pasture 0.01 acres Till Grass Outwash Pasture Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.80 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.01 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 0. 80 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.15 acres Total Area 2.77 acres Peak Discharge: 0.701 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-52.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-52.tsf LogPearson III Coefficients Time Series File:c-52.tsf Project Location:Sea-Tac Mean--0.457 StdDev-0.118 Skew-0.538 Frequencies & Peaks saved to File:c-52.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-52.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-52.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : c-54.tsf B-8 SE 144"' Street-June 2007 Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STTF60H.rnf Till Forest O. 03 acres Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Impervious Loading Time Series 0.03 acres Loading Time Series 0.83 acres File:C:\KC_SWDM\KC DATA\STTP60H.rnf File:C:\KC SWDM\KC DATA\STTG60H.rnf -- Loading Time Series File:C:\KC_SWDM\KC DATA\STOF60H.rnf 0.04 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STOP60H.rnf 0.04 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf 1.24 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STEI60H.rnf 1.44 acres Total Area 3.6S acres Peak Discharge: 0.876 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-54.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-54.tsf LogPearson III Coefficients Time Series File:c-54.tsf Project Location:Sea-Tac Mean~ -0.367 StdDev-0.117 Skew-0.588 Frequencies & Peaks saved to File:c-54.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-54.tsf Durations & Exceedence Probabilities to File:c-54.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : c-60.tsf B-9 SE 14¢" Street-Ju11e 2007 Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 0.52 acres Total Area 0.52 acres Peak Discharge: 0.214 CFS at 0:00 on Oct 6 in 1981 Storing Time Series File:c-60.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-60.tsf Project Location:Sea-Tac Loading Stage/Discharge curve:c-60.tsf LogPearson III Coefficients Mean--0.876 StdDev-0.096 Skew-0.561 Frequencies & Peaks saved to File:c-60.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-60.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-60.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-70.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Pasture Till Grass Outwash Pasture Outwash Grass SE 14.f' Street-June 2007 Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.51 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STTG60H.rnf 1.70 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.34 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 1.13 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf B-10 Impervious 1.34 acres Total Area 5.02 acres Peak Discharge: 1.06 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-70.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-70.tsf LogPearson III Coefficients Time Series File:c-70.tsf Project Location:Sea-Tac Mean--0.327 StdDev-0.133 Skew-0.509 Frequencies & Peaks saved to File:c-70.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-70.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-70.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-80.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass SE 14-f' Street-June 2007 Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf 5.28 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.12 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 4.35 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOF60H.rnf 0. 59 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOP60H.rnf 0.01 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOG60H.rnf 0.48 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf B-II Impervious 3.40 acres Total Area 14.23 acres Peak Discharge: 2.61 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-80.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-80.tsf LogPearson III Coefficients Time Series File:c-80.tsf Project Location:Sea-Tac Mean= 0.090 StdDev-0.131 Skew-0.500 Frequencies & Peaks saved to File:c-80.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-80.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-80.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-90.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf Impervious O. 40 acres Total Area 0.40 acres Peak Discharge: 0.165 CFS at 0:00 on Oct 6 in 1981 SE !4.f'S1reet-June2007 Storing Time Series File:c-90.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module B-12 Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-90.tsf Project Location,: Sea-Tac Loading Stage/Discharge curve:c-90.tsf LogPearson III Coefficients Mean~ -0.989 StdDev~ 0.096 Skew-0.559 Frequencies & Peaks saved to File:c-90.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-90.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-90.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-100.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf 0.45 acres Loading Time Series 0.33 acres Loading Time Series 0.61 acres Loading Time Series 0.17 acres File:C:\KC SWDM\KC DATA1STTP60H.rnf File:C:\KC_SWDM\KC_DATA\STTG60H.rnf File:C:\KC SWDM\KC DATA\STEI60H.rnf -- Total Area 1.56 acres Peak Discharge: 0.250 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-100.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-100.tsf LogPearson III Coefficients B-13 SE 14.f' Strcer -.June 2007 Time Series File:c-100.tsf Project Location:Sea-Tac Mean--1.001 StdDev-0.167 Skew-0.401 Frequencies & Peaks saved to File:c-100.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-100.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-100.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-106.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 2.50 acres Till Pasture Till Grass Outwash Pasture Outwash Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.12 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 3.34 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STOP60H.rnf 0.12 acres Loading Time Series File:C:\KC SWDM\KC DATA\STOG60H.rnf 3.34 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 4.64 acres Total Area 14.06 acres Peak Discharge: 3.02 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-106.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Time Series File:c-106.tsf Loading Stage/Discharge curve:c-106.tsf LogPearson III Coefficients Mean= 0.164 StdDev-0.122 B-14 SE 144'h Street-June 2007 Project Location:Sea-Tac Skew-0. 511 Frequencies & Peaks saved to File:c-106.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-106.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-106.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command Project Location : CREATE a new Time Series Production of Runoff Time Series Sea-Tac Computing Series Regional Scale Factor: c-110. tsf 1. 00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 6.43 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 12.24 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTG60H.rnf 12.33 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 7.10 acres Total Area 38.10 acres Peak Discharge: 6.91 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-110.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-110.tsf LogPearson III Coefficients Time Series File:c-110.tsf Project Location:Sea-Tac Mean= 0.487 StdDev-0.145 Skew-0. 484 SE 14,l' Street-June 2007 Frequencies & Peaks saved to File:c-110.pks Analysis Tools Conunand Compute Flow DURATION and Exceedence B-15 Loading Time Series File:c-110.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-110.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-120.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STTP60H.rnf Till Pasture 0.58 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.00 acres Total Area 1.58 acres Peak Discharge: 0.466 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-120.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Conunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-120.tsf LogPearson III Coefficients Time Series File:c-120.tsf Project Location:Sea-Tac Mean--0.565 StdDev-0.101 Skew-0.475 Frequencies & Peaks saved to File:c-120.pks Analysis Tools Cormnand Compute Flow DURATION and Exceedence Loading Time Series File:c-120.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-120.dur Analysis Tools Command RETURN to Previous Menu B-16 SE 144'1' Stre.et -June 2007 KCRTS Corrunand CREATE a new Time Series of Runoff Time Series Project Location : Production Sea-Tac c-130.tsf 1. 00 Computing Series Regional Scale Factor : Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC_DATA\STTF60H.rnf Till Forest 2.49 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 7.12 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 5.80 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.58 acres Total Area 16.99 acres Peak Discharge: 2.64 CFS at 16:00 on Mar 3 in 1950 Storing Time Series File:c-130.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-130.tsf LogPearson III Coefficients Time Series File:c-130.tsf Project Location:Sea-Tac Mean-0.015 StdDev-0.175 Skew-0.324 Frequencies & Peaks saved to File:c-130.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-130.tsf Computing Interval Locations Computing Flow Durations SE 14.f' Street-June 2007 Durations & Exceedence Probabilities to File:c-130.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series B-17 Project Location : Sea-Tac Computing Series c-200.tsf Regional Scale Factor : 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 4.45 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf 0.14 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 1.79 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.18 acres Total Area 7.56 acres Peak Discharge: 1.12 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-200.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-200.tsf LogPearson III Coefficients Time Series File:c-200.tsf Project Location:Sea-Tac Mean--0.308 StdDev-0.145 Skew-0. 500 Frequencies & Peaks saved to File:c-200.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-200.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File;c-200.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-210.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf B-18 SE J4 .. f>' Street-June 2007 Till Forest Till Pasture Till Grass Impervious 3.31 acres Loading Time Series File: C: \KC SWDM\KC DATA \STTP60H. rnf 1.70 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTG60H.rnf 4.60 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 2. 93 acres Total Area 12.54 acres Peak Discharge: 2.47 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-210.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-210.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-210.tsf Project Location:Sea-Tac Mean-0.056 StdDev-0.136 Skew-0. 482 Frequencies & Peaks saved to File:c-210.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-210.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-210.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-220.tsf Regional Scale Factor : 1.00 Data Type: Historic Creating Hourly Time Series File Till Grass Loading Time Series File:C:\KC_SWDM\KC DATA\STTG60H.rnf 1.56 acres Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.90 acres Total Area 3.46 acres Peak Discharge: 1.09 CFS at 6:00 on Jan 9 in 1990 B·19 SE /4,f° Stree/-June 2007 Storing Time Series File:c-220.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-220.tsf LogPearson III Coefficients Time Series File:c-220.tsf Project Location:Sea-Tac Mean~ -0.235 StdDev-0.114 Skew-0.400 Frequencies & Peaks saved to File:c-220.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-220.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-220.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-230.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP60H.rnf Till Pasture 3. 95 acres Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 5.71 acres Total Area 9.66 acres Peak Discharge: 2.72 CFS at 6:00 on Jan 9 in 1990 SE 144"' Srreet-June '1007 Storing Time Series File:c-230.tsf Time Series Computed KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command B-20 Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-230.tsf LogPearson III Coefficients Time Series File:c-230.tsf Project Location:Sea-Tac Mean-0.197 StdDev-0.103 Skew-0.461 Frequencies & Peaks saved to File:c-230.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-230.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-230.dur Analysis Tools Corrunand RETURN to Previous Menu KCRTS Cormnand CREATE a new.Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-232.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Till Forest Loading Time Series File :C: \KC SWDM\KC DATA \STTF60H .rnf 1.38 acres Total Area 1.38 acres Peak Discharge: 0.093 CFS at 9:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-232&tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-232.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-232.tsf Project Location:Sea-Tac Mean--1.477 StdDev-0.232 Skew--0.124 SE 14.f' Street-June 2007 Frequencies & Peaks saved to File:c-232.pks Analysis Tools Command Compute Flow DURATION and Exceedence B-21 Loading Time Series File:c-232.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-232.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location ; Sea-Tac Computing Series c-240.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf Till Grass 3.65 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 4.48 acres Total Area 8.13 acres Peak Discharge: 2.56 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-240.tsf Time Series Computed KCRTS Conunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-240.tsf LogPearson III Coefficients Time Series File:c-240.tsf Project Location:Sea-Tac Mean= 0.137 StdDev-0.114 Skew-0. 402 Frequencies & Peaks saved to File:c-240.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-240.tsf Durations & Exceedence Probabilities to File:c-240~dur SE 144"' Street-June 2007 Analysis Tools Command RETURN to Previous Menu B-22 KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-241.tsf Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC DATA\STTF60H.rnf 0.23 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STTG60H.rnf 2.99 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3.68 acres Total Area 6.90 acres Peak Discharge: 2.12 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-241.tsf Time Series Computed KCRTS Conunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-241.tsf LogPearson III Coefficients Time Series File:c-241.tsf Project Location:Sea-Tac Mean-0.052 StdDev-0.114 Skew-0.403 Frequencies & Peaks saved to File:c-241.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-241.tsf Durations & Exceedence Probabilities to File:c-241.dur Analysis Tools Command RETURN to Previous Menu KCRTS Conunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : c-244.tsf B-23 SE 144'1' Streel-Jurre 2007 Regional Scale Factor: 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 0. 71 acres Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 11.46 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 10.75 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf 4.68 acres Total Area 27.60 acres Peak Discharge: 5.19 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-244.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-244.tsf LogPearson III Coefficients Time Series File:c-244.tsf Project Location:Sea-Tac Mean= 0.350 StdDev-0.151 Skew-0.463 Frequencies & Peaks saved to File:c-244.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-244.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-244.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location ; Sea-Tac Computing Series c-250.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC_SWDM\KC DATA\STTP60H.rnf Till Pasture 0.17 acres Loading Time Series File:C:\KC_SWDM\KC DATA\STTG60H.rnf B-24 SE 144'" Street-June 2007 Till Grass Impervious 4.66 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3.23 acres Total Area 8.06 acres Peak Discharge: 2.27 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-250.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-250.tsf LogPearson III Coefficients Time Series File:c-250.tsf Project Location:Sea-Tac Mean:a:c. 0.048 StdDev~ 0.126 Skew~ 0 .396 Frequencies & Peaks saved to File:c-250.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-250.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-250.dur Analysis Tools Conunand RETURN to Previous Menu KCRTS Command CREATE a new Time Series of Runoff Time Series Project Location : Production Sea-Tac c-260.tsf 1. 00 Computing Series Regional Scale Factor: Data Type: Historic Creating Hourly Time Series File Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTG60H.rnf 2.33 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.74 acres Total Area 4.07 acres Peak Discharge: 1.18 CFS at 6:00 on Jan 9 in 1990 SE 144"' Street-June 2007 Storing Time Series File:c-260.tsf Time Series Computed KCRTS Command B-25 Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-260.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-260.tsf Project Location:Sea-Tac Mean= -0.230 StdDev= 0.124 Skew= 0.395 Frequencies & Peaks saved to File:c-260.pks Analysis Tools Command Compute Flow DURATION and Exceedence 'Loading Time Series File:c-260.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c~260.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-270.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf Till Grass 2.22 acres Impervious Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 1.60 acres Total Area 3.82 acres Peak Discharge: 1.10 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-270.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-270.tsf LogPearson III Coefficients B-26 SE 144'1: Street -June 2007 Time Series File:c-270.tsf Project Location:Sea-Tac Mean--0.263 StdDev~ 0.125 Skew-0.392 Frequencies & Peaks saved to File:c-270.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-270.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-270.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-300.tsf Regional Scale Factor: 1.00 Data Type: Historic Creating Hourly Time Series File', Till Forest Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF6DH.rnf 9.47 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STTP6DH.rnf 1.73 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 4.13 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf 1.56 acres Total Area 16.89 acres Peak Discharge: 2.19 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-300.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-300.tsf LogPearson III Coefficients -------------------------------------------------------- Time Series File:c-300.tsf Project Location:Sea-Tac Mean--0.057 StdDev-0.172 Skew-0.335 Frequencies & Peaks saved to File:c-3DO~pks Analysis Tools Command B-27 SE 144~ Street-June 2007 Compute Flow DURATION and Exceedence Loading Time Series File:c-300.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-300.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-304.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Impervious Loading Time Series File:C:\KC_SWDM\KC_DATA\STTF60H.rnf 2.12 acres Loading Time Series Fi,le:C:\KC_SWDM\KC_DATA\STTP60H.rnf 1.36 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 5.73 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 3. 74 acres Total Area 12.95 acres Peak Discharge: 2.93 CFS at 6:00 on Jan 9 in 1990 Storing Time Series File:c-304.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-304.tsf LogPearson III Coefficients Time Series File:c-304.tsf Project Location:Sea-Tac Mean= 0.141 StdDev= 0.132 Skew= 0.426 Frequencies & Peaks saved to File:c-304.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations SE I 4,tn Street-June 2007 Loading Time Series File:c-304.tsf B-28 Durations & Exceedence Probabilities to File:c-304.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-306.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Till Forest Till Pasture Till Grass Impervious Loading Time Series File:C:\KC SWDM\KC_DATA\STTF60H.rnf 1.25 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.15 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.28 acres Loading Time Series File:C:\KC SWDM\KC DATA\STEI60H.rnf 0.08 acres Total Area 1.76 acres Peak Discharge: 0.177 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-306.tsf KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-306.tsf LogPearson III Coefficients Time Series File:c-306.tsf Project Location:Sea-Tac Mean--1.180 StdDev-0.204 Skew-0.041 Frequencies & Peaks saved to File:c-306.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-306.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-306.dur SE 144'1' Streel-Junc 2007 Analysis Tools Command RETURN to Previous Menu B-29 KCRTS Command CREATE a new Time Series Project Location : Production of Runoff Time Series Sea-Tac Computing Series Regional Scale Factor: c-310.tsf 1. 00 Data Type: Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 9.32 acres Total Area 9.32 Peak Discharge: 0.627 CFS at acres 9:00 on Jan 9 in 1990 Storing Time Time Series Computed KCRTS Command Series File:c-310.tsf Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-310.tsf LogPearson III Coefficients Time Series File:c-310.tsf Project Location:Sea-Tac Mean= -0.648 StdDev= 0.233 Skew= -0.139 Frequencies & Peaks saved to File:c-310.pks Analysis Tools Command Compute Flow DURATION and Exceedence Computing Interval Locations Computing Flow Durations Loading Time Series File:c-310.tsf Durations & Exceedence Probabilities to File:c-310.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-320.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf B-30 SE 144"' Street-June 2007 Till Forest Till Pasture Till Grass Impervious 8.92 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.18 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0.33 acres Loading Time Series File:C:\KC SWDM\KC_DATA\STEI60H.rnf 0.09 acres Total Area 9.52 acres Peak Discharge: 0.693 CFS at 9:00 on Jan 9 in 1990 Storing Time Series File:c-320.tsf Time Series Computed KCRTS Command Enter the Analysis TOOLS Module Analysis Tools Corrunand Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-320.tsf LogPearson III Coefficients Time Series File:c-320.tsf Project Location:Sea-Tac Mean= -0.597 StdDev= 0.226 Skew= -0.141 Frequencies & Peaks saved to File:c-320.pks Analysis Tools Corrunand Compute Flow DURATION and Exceedence Loading Time Series File:c-320.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-320.dur Analysis Tools Command RETURN to Previous Menu KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series c-330.tsf Regional Scale Factor : 1.00 Data Type : Historic Creating Hourly Time Series File Loading Time Series File:C:\KC SWDM\KC DATA\STTF60H.rnf Till Forest 1.37 acres Till Pasture Till Grass SE J4,fl• Street-June 2007 Loading Time Series File:C:\KC SWDM\KC DATA\STTP60H.rnf 0.34 acres Loading Time Series File:C:\KC SWDM\KC DATA\STTG60H.rnf 0. 62 acres Loading Time Series File:C:\KC_SWDM\KC_DATA\STEI60H.rnf B-31 Impervious 0.17 acres Total Area 2.50 acres Peak Discharge: 0.307 CFS at 6:00 on Jan 9 in 1990 Storing Time Time Series Computed Series File:c-330.tsf KCRTS Corrunand Enter the Analysis TOOLS Module Analysis Tools Command Compute PEAKS and Flow Frequencies Flow Frequency Analysis Loading Stage/Discharge curve:c-330.tsf LogPearson III Coefficients Time Series File:c-330.tsf Project Location:Sea-Tac Mean--0.930 StdDev= 0.187 Skew-0.198 Frequencies & Peaks saved to File:c-330.pks Analysis Tools Command Compute Flow DURATION and Exceedence Loading Time Series File:c-330.tsf Computing Interval Locations Computing Flow Durations Durations & Exceedence Probabilities to File:c-330.dur Analysis Tools Command RETURN to Previous Menu KCRTS Corrunand eXit KCRTS Program B-32 SE 14¢" Street-June 2007 Appendix 8.2 KCRTS Pond Designs Hamilton Place -Retention/Detention Facility Type of Facility: Detention Pond Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage 0 Elevation: Storage Volume: Riser Head: Riser Number Orifice# 1 2 of Diameter: orifices: Height {ft) 0.00 2.90 3.00 H:lV 145. 91 ft 71. 63 ft 10452. sq. ft 19580. sq. ft 0. 44 9 acres 5.00 ft 505.00 ft 7 007 6. cu. ft 1. 609 ac-ft 5.00 12.00 2 Diameter (in) 1.26 1. 70 ft inches Full Head Discharge (CFS) 0 .096 0 .114 Top Notch Weir: None Outflow Rating Curve: None Evendell Plat -Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 3.00 H:lV Pond Bottom Length: 167.00 ft Pond Bottom Width: 58.00 ft Pond Bottom Area: 968 6. sq. ft Top Area at 1 ft. FB: 23762. sq. ft 0.546 acres Effective Storage Depth: 7.50 ft Stage 0 Elevation: 452.00 ft Storage Volume: 115676. cu. ft 2.656 ac-ft Riser Head: 7.50 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Orifice # Height Diameter Discharge (ft) (in) (CFS) 1 0.00 1. 50 0.167 2 5.50 2.30 0.203 3 5.90 2.80 0.269 Top Notch Weir: None Outflow Rating Curve: None Liberty Grove -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: SE J 4,th Streel -June 2007 Detention Pond 2.00 H:lV 178.12 ft 89.06 ft B-33 Pipe Diameter (in) 4.0 Pipe Diameter (in) 6.0 6.0 Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice#" 1 2 3 Height (ft) 0.00 3.65 4. 81 15863. 24128. 0. 554 6.00 456.00 115567. 2.653 6.00 18.00 3 sq. ft sq. ft acres ft ft cu. ft ac-ft ft inches Diameter (in) 3.31 4.39 7.69 Full Head Discharge (CFS) 0. 728 0.801 1.749 Top Notch Weir: None Outflow Rating Curve: None Nichol's Place -Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice # Height (ft) 1 0.00 2 3. 90 Top Notch Weir: Length: Weir Height: Outflow Rating Curve: SE 14.f' Screer-Jrme 2007 Detention Pond 0.00 H:lV 82.00 ft 71.00 ft 5822. sq. ft 5822. sq. ft 0.134 acres 5.00 ft 447.00 ft 29110. cu. ft 0.668 ac-ft 5.00 ft 18.00 inches 2 Full Head Diameter Discharge (in) (CFS) 0.87 0.046 1. 71 0.083 Rectangular 1. 00 in 4. 50 ft None B-34 Pipe Diameter (in) 8.0 10.0 Pipe Diameter (in) 4.0 Appendix B.3 KCRTS Peak Flow Rates Flow Frequency Analysis Log Pearson III Coefficients Time Series File:c-10.tsf Mean= -1. 641 StdDev= 0.141 Project Location;Sea-Tac Skew= 1.196 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0 .022 26 2/16/49 21: 00 0.070 1 89.50 0.989 0. 07 0 1 3/03/50 16: 00 0.046 2 32 .13 0. 969 0.034 6 2/09/51 2: 00 0.044 3 19.58 0.949 0. 018 37 10/15/51 13: 00 0.039 4 14.08 0.929 0.017 44 3/24/53 15:00 0.036 5 10.99 0.909 0 .022 27 12/19/53 19: 00 0.034 6 9.01 0. 889 0.023 21 2/07/55 17: 00 0.033 7 7.64 0. 8 69 0.025 15 12/20/55 17:00 0.031 8 6.63 0. 849 0.022 22 12/09/56 14:00 0.031 9 5. 86 0. 82 9 0. 021 28 12/25/57 16: 00 0.030 10 5.24 0. 809 0. 021 29 1/26/59 20:00 0.028 11 4.75 0. 78 9 0. 02 5 17 2/06/60 17:00 0.028 12 4.34 0. 769 0. 02 6 13 2/14/61 21:00 0.026 13 3.99 0. 74 9 0.018 38 11/22/61 2:00 0.025 14 3.70 0. 729 0. 019 34 12/15/62 2:00 0.025 15 3.44 0. 709 0. 022 23 12/31/63 23:00 0.025 16 3.22 0.690 0.018 39 12/21/64 4:00 0.025 17 3.03 0.670 0.018 40 1/05/66 16:00 0.024 18 2.85 0.650 0. 028 12 1/19/67 14:00 0.024 19 2.70 0.630 0.030 10 8/24/68 16:00 0.023 20 2.56 0.610 0.016 46 12/03/68 16:00 0.023 21 2.44 0.590 0.018 41 1/13/70 22:00 0 .022 22 2.32 0.570 0.018 42 12/05/70 9:00 0.022 23 2.22 0.550 0. 044 3 2/27 /72 7: 00 0.022 24 2.13 0.530 0.017 45 1/13/73 2: 00 0. 022 25 2.04 0.510 0.018 35 11/28/73 9:00 0.022 26 1. 96 0. 490 0.023 20 12/26/74 23:00 0.022 27 1. 89 0.470 0.016 47 1/14/76 6:00 0.021 28 1. 82 0.450 0.020 30 8/26/77 2:00 0.021 29 1. 75 0.430 0.028 11 9/17/78 2:00 0.020 30 1. 70 0.410 0.025 14 9/08/79 15:00 0.020 31 1.64 0.390 0.022 25 12/14/79 21:00 0.019 32 1. 59 0.370 0.024 18 11/21/80 11: 00 0.019 33 1. 54 0.350 0.033 7 10/06/81 0:00 0.019 34 1. 49 0.330 0.025 16 10/28/82 16: 00 0.018 35 1. 45 0.310 0.020 31 3/15/84 20:00 0.018 36 1. 41 0. 2 91 0 .017 43 6/06/85 22:00 0.018 37 1.37 0.271 0.022 24 1/18/86 16:00 0.018 38 1.33 0.251 0.031 9 10/26/86 0:00 0.018 39 1. 30 0.231 0.015 49 11/11/87 0:00 0.018 40 1.27 0.211 0.019 32 8/21/89 17: 00 0.018 41 1.24 0 .191 0.046 2 1/09/90 8:00 0.018 42 1.21 0.171 0.036 5 11/24/90 8:00 0.017 43 1.18 0.151 0. 018 36 1/27/92 15:00 0.017 44 1.15 0.131 0.013 50 11/01/92 16:00 0.017 45 1.12 0 .111 0.015 48 11/30/93 22:00 0.016 46 1.10 0. 091 0.019 33 11/30/94 4:00 0.016 47 1. 08 0. 071 0.039 4 2/08/96 10:00 0.015 48 1. 05 0.051 0.031 8 1/02/97 6:00 0.015 49 1. 03 0.031 0. 024 19 10/04/97 15:00 0.013 50 1. 01 0.011 B-35 SE 14.f' Street-Jr.me 2007 Computed Peaks 0.063 100.00 0. 990 Computed Peaks 0.053 50.00 0.980 Computed Peaks 0.045 25.00 0. 960 Computed Peaks 0.035 10.00 0.900 Computed Peaks 0.034 8.00 0.875 Computed Peaks 0.029 5.00 0.800 Computed Peaks 0.021 2.00 0.500 Computed Peaks 0.018 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-20.tsf Mean= -0.857 StdDev-0 .119 Project Location:Sea-Tac Skew= 0.941 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.135 24 2/16/49 21 :00 0.331 l 89.50 0.989 0.331 1 3/03/50 16:00 0.258 2 32.13 0.969 0.173 10 2/09/51 2:00 0.222 3 19.58 0.949 0 .115 37 10/15/51 13:00 0.218 4 14. 08 0.929 0.106 44 3/24/53 15:00 0.210 5 10.99 0.909 0.132 27 12/19/53 19:00 0 .197 6 9.01 0.889 0 .133 26 2/07/55 17 :00 0 .195 7 7.64 0. 869 0.139 22 12/20/55 17:00 0 .191 8 6.63 0.849 0.143 18 12/09/56 14 :00 0.178 9 5.86 0. 829 0.132 28 12/25/57 16:00 0.173 10 5.24 0.809 0 .116 34 1/26/59 20:00 0 .170 11 4.75 0.789 0.135 23 2/06/60 17:00 0.170 12 4.34 0. 769 0.140 21 2/14/61 21 :00 0 .160 13 3.99 0.749 0 .114 38 11/22/61 2:00 0.158 14 3.70 0.729 0.114 39 12/15/62 2:00 0.155 15 3.44 0.709 0.135 25 12/31/63 23:00 0.150 16 3.22 0.690 0.115 36 12/21/64 4:00 0.149 17 3.03 0.670 0.114 40 1/05/66 16:00 0.143 18 2.85 0.650 0.170 11 11/13/66 19:00 0.140 19 2.70 0.630 0 .191 8 8/24/68 16:00 0.140 20 2.56 0.610 0.103 46 12/03/68 16:00 0.140 21 2.44 0. 590 0 .113 41 1/13/70 22:00 0.139 22 2.32 0.570 0 .111 42 12/05/70 9:00 0 .135 23 2.22 0.550 0.222 3 2/27 /72 7:00 0.135 24 2.13 0.530 0.104 45 1/13/73 2:00 0.135 25 2.04 0.510 0.116 35 11/28/73 9:00 0.133 26 1. 96 0. 490 0.149 17 12/26/74 23:00 0.132 27 1. 89 0.470 0.102 47 11/13/75 19:00 0.132 28 1. 82 0.450 0.129 29 8/26/77 2:00 0.129 29 1. 75 0.430 0.178 9 9/17/78 2:00 0.123 30 1. 70 0.410 0 .160 13 9/08/79 15:00 0.122 31 1. 64 0.390 0.140 19 12/14/79 21:00 0.121 32 1.59 0.370 0.155 15 11/21/80 11:00 0 .117 33 1.54 0.350 0.210 5 10/06/81 0:00 0.116 34 1.49 0.330 0 .158 14 10/28/82 16:00 0 .116 35 1. 45 0.310 0.123 30 3/15/84 20:00 0 .115 36 1.41 0. 2 91 0.110 43 6/06/85 22:00 0.115 37 1.37 0.271 0.140 20 1/18/86 16: 00 0 .114 38 1. 33 0.251 0 .197 6 10/26/86 0:00 0 .114 39 1.30 0. 231 0. 0 94 49 11/11/87 0:00 0 .114 40 1. 27 0. 211 0 .122 31 8/21/89 17:00 0 .113 41 1. 24 , 0 .191 0.258 2 1/09/90 6:00 0 .111 42 1. 21 0.171 0.218 4 11/24/90 8:00 0 .110 43 1.18 0.151 0 .117 33 1/27 /92 15:00 0.106 44 1.15 0.131 B-36 SE 144'h Street-June 2007 0. 08 6 50 11/01/92 16: 00 0.104 45 1.12 0.111 0.097 48 11/30/93 22:00 0.103 46 1.10 0.091 0.121 32 11/30/94 4:00 0 .102 47 1. 08 0. 071 0.195 7 2/08/96 10:00 0.097 48 1. 05 0.051 0.170 12 1/02/97 6:00 0.094 49 1. 03 0.031 0.150 16 10/04/97 15:00 0.086 50 l. 01 0. 011 Computed Peaks 0.315 100.00 0.990 Computed Peaks 0.277 50.00 0.980 Computed Peaks 0.242 25.00 0.960 Computed Peaks 0.201 10.00 0.900 Computed Peaks 0.193 8.00 0.875 Computed Peaks 0 .171 5.00 0.800 Computed Peaks 0.133 2.00 0.500 Computed Peaks 0 .112 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-30. tsf Mean= -0.949 StdDev= 0.121 Project Location:Sea-Tac Skew-0.973 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.109 25 2/16/49 21:00 0.276 1 89.50 0.989 0. 27 6 1 3/03/50 16:00 0.210 2 32.13 0.969 0.143 9 2/09/51 2:00 0.183 3 19.58 0.949 0.092 37 10/15/51 13: 00 0 .176 4 14.08 0.929 0.086 44 3/24 / 53 15:00 0.169 5 10.99 0.909 0.106 27 12/19/53 19: 00 0.161 6 9.01 0. 889 0.108 26 2/07/55 17:00 0.158 7 7.64 0.869 0 .114 20 12/20/55 17:00 0.154 8 6.63 0.849 0.116 18 12/09/56 14:00 0.143 9 5.86 0. 829 0.106 28 12/25/57 16: 00 0.143 10 5.24 0.809 0.095 33 1/26/59 20:00 0 .139 11 4.75 0.789 0 .110 23 2/06/60 17:00 0 .137 12 4.34 0.769 0 .114 19 2/14/61 21:00 0.129 13 3.99 0.749 0.092 38 11/22/61 2:00 0.127 14 3.70 0. 729 0. 092 39 12/15/62 2:00 0.124 15 3.44 0.709 0.109 24 12/31 / 63 23:00 0.121 16 3.22 0.690 0.093 36 12/21/64 4:00 0.120 17 3.03 0. 670 0. 091 40 1/05/66 16: 00 0 .116 18 2.85 0.650 0.137 12 11/13/66 19: 00 0 .114 19 2.70 0.630 0.154 8 8/24/68 16: 00 0 .114 20 2.56 0. 610 0.083 46 12/03/68 16:00 0 .113 21 2.44 0.590 0. 091 41 1/13/70 22:00 0 .113 22 2.32 0.570 0.089 42 12/05/70 9:00 0 .110 23 2.22 0.550 0.183 3 2/27 /72 7:00 0.109 24 2.13 0.530 0.084 45 1/13/73 2:00 0.109 25 2.04 0. 510 0.093 35 11/28/73 9:00 0.108 26 1.96 0.490 0.120 17 12/26/74 23:00 0.106 27 1. 89 0.470 0.082 47 11/13/75 19:00 0.106 28 1.82 0.450 0 .104 29 8/26/77 2:00 0.104 29 1.75 0.430 0 .143 10 9/17/78 2:00 0.099 30 1. 70 0.410 0.129 13 9/08/79 15:00 0.098 31 1. 64 0.390 0 .113 21 12/14/79 21:00 0.097 32 1. 59 0. 370 0.124 15 11/21/80 11 :00 0.095 33 1.54 0.350 0 .169 5 10/06/81 0:00 0. 094 34 1. 49 0.330 0 .127 14 10/28/82 16: 00 0.093 35 1.45 0.310 0.099 30 3/15/84 20:00 0.093 36 1.41 0.291 0.088 43 6/06/85 22:00 0. 092 37 1.37 0. 271 0 .113 22 1/18/86 16: 00 0. 092 38 1.33 0. 251 B-37 SE 144'1' Srreet-June 2007 0.158 7 10/26/86 0:00 0.092 39 1.30 0.231 0.076 49 11/11/87 0:00 0.091 40 1.27 0. 211 0.098 31 8/21/89 17:00 0.091 41 1.24 0 .191 0.210 2 1/09/90 6:00 0. 08 9 42 1. 21 0 .171 0 .176 4 11/24/90 8:00 0.088 43 1. 18 0.151 0.094 34 1/27/92 15:00 0.086 44 1.15 0.131 0.069 50 11/01/92 16:00 0.084 45 1.12 0 .111 0.078 48 11/30/93 22:00 0.083 46 1.10 0.091 0.097 32 11/30/94 4:00 0.082 47 1. 08 0.071 0.161 6 2/08/96 10:00 0.078 48 1. 05 0.051 0.139 11 1/02/97 6:00 0.076 49 1. 03 0.031 0.121 16 10/04/97 15:00 0.069 50 1. 01 0.011 Computed Peaks 0.259 100.00 0.990 Computed Peaks 0.227 50.00 0.980 Computed Peaks 0 .198 25.00 0.960 Computed Peaks 0 .163 10.00 0.900 Computed Peaks 0.157 8.00 0.875 Computed Peaks 0.139 5.00 0.800 Computed Peaks 0.107 2.00 0.500 Computed Peaks 0.090 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-40.tsf Mean= -1.104 StdDev-0.105 Project Location:Sea-Tac Skew= 0.664 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.078 21 2/16/49 21:00 0.145 1 89.50 0.989 0 .14 5 1 3/03/50 16:00 0.135 2 32.13 0. 969 0.085 17 2/09/51 2:00 0.124 3 19.58 0. 949 0.068 35 10/15/51 13:00 0.121 4 14.08 0.929 0.062 43 3/24/53 15:00 0 .116 5 10.99 0.909 0.074 27 12/19/53 19:00 0.112 6 9.01 0.889 0.077 23 11/25/54 2:00 0.107 7 7. 64 0.869 0.075 26 11/18/55 15:00 0.105 8 6.63 0. 849 0.084 18 12/09/56 14:00 0 .100 9 5.86 0.829 0 .077 22 12/25/57 16:00 0.094 10 5.24 0.809 0. 061 44 1/26/59 20:00 0.094 11 4.75 0.789 0 .072 28 11/20/59 5:00 0.093 12 4.34 0.769 0 .072 29 2/14/61 21:00 0.091 13 3.99 0.749 0. 067 37 11/22/61 2:00 0.089 14 3.70 0.729 0.065 40 12/15/62 2:00 0.088 15 3.44 0.709 0.076 24 12/31/63 23:00 0.088 16 3.22 0.690 0. 067 36 12/21/64 4:00 0.085 17 3.03 0.670 0.066 39 1/05/66 16:00 0.084 18 2.85 0.650 0.100 9 11/13/66 19:00 0.083 19 2.70 0.630 0 .112 6 8/24/68 16:00 0.080 20 2.56 0.610 0.060 45 12/03/68 16:00 0.078 21 2.44 0.590 0. 067 38 1/13/70 22:00 0. 077 22 2.32 0.570 0. 065 41 12/05/70 9:00 0.077 23 2.22 0.550 0.107 7 2/27 /72 7:00 0. 07 6 24 2.13 0.530 0. 060 46 1/13/73 2:00 0.076 25 2.04 0.510 0.068 34 11/28/73 9:00 0.075 26 1. 96 0.490 0.088 15 12/26/74 23:00 0.074 27 1. 89 0.470 0. 060 47 11/13/75 19:00 0.072 28 1. 82 0.450 0.076 25 8/26/77 2:00 0.072 29 1. 75 0.430 0.105 8 9/17 /78 2:00 0.072 30 1.70 0.410 0.094 10 9/08/79 15:00 0.071 31 1. 64 0.390 0.083 19 12/14/79 21:00 0.070 32 1. 59 0.370 B-38 SE 144'1' Streel-June 1007 0.091 13 11/21/80 11:00 0.069 33 1. 54 0.350 0 .124 3 10/06/81 0:00 0.068 34 1. 49 a .330 0.093 12 10/28/82 16:00 0.068 35 1.45 0. 310 0. 07 0 32 1/03/84 1: 00 o. o 67 36 1. 41 0. 291 0. 064 42 6/06/85 22:00 0. 067 37 1. 37 0 .271 0. 08 0 20 1/18/86 16:00 0. 067 38 1.33 0. 251 0 .116 5 10/26/86 0:00 0.066 39 1.30 0 .231 0.055 49 11/11/87 0:00 0. 065 40 1.27 0.211 0.072 30 8/21/89 17: 00 0.065 41 1.24 0.191 0.135 2 1/09/90 6:00 0.064 42 1.21 0 .1 71 0.121 4 11/24/90 8:00 0.062 43 1.18 0 .151 0.069 33 1/27/92 15:00 0.061 44 1.15 0 .131 0.050 50 11/01/92 16:00 0.060 45 1.12 0.111 0.057 48 9/03/94 10:00 0.060 46 1.10 0. 0 91 0.071 31 11/30/94 4: 00 0.060 47 1. 08 0. 071 0.094 11 2/08/96 10:00 0. 057 48 1. 05 0. 051 0.088 16 1/02/97 6:00 0.055 49 1. 03 0. 031 0.089 14 10/04/97 15:00 0.050 50 1. 01 0.011 Computed Peaks 0.154 100.00 0.990 Computed Peaks 0.140 50.00 0.980 Computed Peaks 0.126 25.00 0. 960 Computed Peaks 0.108 10.00 0.900 Computed Peaks 0.105 8.00 0. 87 5 Computed Peaks 0.095 5.00 0.800 Computed Peaks 0.077 2.00 0.500 Computed Peaks 0. 065 1.30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-42. tsf Mean= -0.747 StdDev-0 .110 Project Location:Sea-Tac Skew= 0. 794 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.175 21 2/16/49 21:00 0.372 1 89.50 0. 989 0.372 1 3/03/50 16:00 0.319 2 32 .13 0. 969 0.207 14 2/09/51 2:00 0.277 3 19.58 0. 94 9 0. 151 36 10/15/51 13:00 0.276 4 14. 08 0. 929 0.139 44 3/24/53 15: 00 0.263 5 10.99 0. 909 0.169 28 12/19/53 19:00 0.259 6 9.01 0. 889 0.172 25 11/25/54 2:00 0.251 7 7. 64 0. 869 0 .1 72 23 12/20/55 17:00 0 .234 8 6.63 0. 849 0.188 18 12/09/56 14:00 0.230 9 5.86 0. 829 0 .1 72 24 12/25/57 16:00 0.224 10 5.24 0.809 0.144 43 1/26/59 20:00 0.210 11 4.75 0.789 0 .167 29 2/06/60 17:00 0.209 12 4.34 0.769 0 .171 26 2/14/61 21:00 0.208 13 3.99 0. 74 9 0.149 37 11/22/61 2:00 0 .207 14 3.70 0. 729 0 .147 40 12/15/62 2: 00· 0.203 15 3.44 0.709 0.174 22 12/31/63 23:00 0.197 16 3.22 0.690 0.151 35 12/21/64 4:00 0.196 17 3.03 0.670 0 .14 9 38 1/05/66 16:00 0.188 18 2.85 0.650 0.224 10 11/13/66 19:00 0.185 19 2.70 0. 630 0.251 7 8/24/68 16:00 0 .182 20 2.56 0.610 0.135 46 12/03/68 16: 00 0.175 21 2.44 0.590 0.148 39 1/13/70 22:00 0.174 22 2.32 0.570 0 .146 41 12/05/70 9:00 0.172 23 2.22 0.550 0. 263 5 2/27 /72 7:00 0 .172 24 2.13 0.530 0.136 45 1/13/73 2:00 0 .172 25 2.04 0.510 0.153 34 11/28/73 9:00 0.171 26 1. 96 0.490 B-39 SE 144'n Streel-June 2007 0 .196 17 12/26/74 23:00 0.170 27 1. 89 0.470 0.134 47 11/13/75 19:00 0 .169 28 1. 82 0.450 0.170 27 8/26/77 2:00 0 .167 29 1. 75 0.430 0.234 8 9/17 /78 2:00 0 .160 30 1. 70 0.410 0.210 11 9/08/79 15:00 0.158 31 1. 64 0. 390 0.185 19 12/14/79 21:00 0.158 32 1. 59 0.370 0.203 15 11/21/80 11: 00 0.154 33 1. 54 0.350 0.276 4 10/06/81 0:00 0.153 34 1. 49 0.330 0.208 13 10/28/82 16:00 0.151 35 1. 45 0.310 0.158 32 1/03/84 1:00 0.151 36 1. 41 0. 291 0 .144 42 6/06/85 22:00 0 .14 9 37 1. 37 0.271 0.182 20 1/18/86 16:00 0 .14 9 38 1.33 0. 251 0.259 6 10/26/86 0:00 0.148 39 1. 30 0. 231 0.124 49 11/11/87 0:00 0.147 40 1. 27 0.211 0.160 30 8/21/89 17:00 0 .14 6 41 1. 24 0 .191 0.319 2 1/09/90 6:00 0.144 42 1. 21 0.171 0 .277 3 11/24/90 8:00 0.144 43 1.18 0.151 0.154 33 1/27/92 15:00 0.139 44 1.15 0.131 0.113 50 11/01/92 16:00 0 .136 45 1.12 0.111 0.128 48 11/30/93 22:00 0.135 46 1.10 0.091 0.158 31 11/30/94 4:00 0 .134 47 1. 08 0.071 0.230 9 2/08/ 96 10:00 0.128 48 1. 05 0. 051 0. 20 9 12 1/02/97 6:00 0.124 49 1.03 0.031 0.197 16 10/04/97 15:00 0 .113 50 1. 01 0.011 Computed Peaks 0.373 100.00 0.990 Computed Peaks 0.334 50.00 0.980 Computed Peaks 0.297 25.00 0.960 Computed Peaks 0.251 10.00 0.900 Computed Peaks 0.243 8.00 0.875 Computed Peaks 0.218 5.00 0.800 Computed Peaks 0.173 2.00 0.500 Computed Peaks 0.147 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-44.tsf Mean= -0. 596 StdDev= 0. 096 Project Location:Sea-Tac Skew= 0.562 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.253 21 2/16/49 21:00 0.407 1 89.50 0.989 0.368 6 3/03/50 16:00 0.407 2 32.13 o. 969 0.246 25 2/09/51 2:00 0.382 3 19.58 0. 94 9 0.223 34 10/15/51 13:00 0.382 4 14. 08 0.929 0.203 43 3/24/53 15:00 0.370 5 10.99 0.909 0.239 28 12/19/53 19:00 0.368 6 9.01 0.889 0.253 22 11/25/54 2:00 0.345 7 7.64 0. 8 69 0.247 24 11/18/55 15:00 0.330 8 6.63 0.849 0. 278 15 12/09/56 14:00 0.310 9 5. 8 6 0. 829 0.254 20 12/25/57 16: 00 0.307 10 5.24 0.809 0.194 47 11/03/58 17:00 0.303 11 4.75 0.789 0.239 27 11/20/59 5:00 0.300 12 4.34 0. 7 69 0.214 40 2/14/61 21 :00 0.292 13 3.99 0.749 0.221 36 11/22/61 2:00 0.289 14 3.70 0. 729 0. 211 42 12/15/62 2:00 0.278 15 3.44 0.709 0.244 26 12/31/63 23:00 0.273 16 3.22 0. 690 0.221 35 12/21/64 4:00 0.268 17 3.03 0.670 0.219 38 1/05/66 16:00 0. 262 18 2.85 0.650 0. 330 8 11/13/66 19:00 0. 2 60 19 2.70 0.630 0.370 5 8/24/68 16:00 0.254 20 2.56 0.610 B-40 SE J 4,f Street -June 2007 0.198 44 12/03/68 16:00 0.253 21 2.44 0.590 0.220 37 1/13/70 22:00 0.253 22 2.32 0.570 0. 215 39 12/05/70 9:00 0.251 23 2.22 0.550 0.303 11 12/08/71 18:00 0.247 24 2.13 0.530 0.197 46 1/13/73 2:00 0.246 25 2.04 0.510 0.226 33 11/28/73 9:00 0.244 26 1. 96 0.490 0.289 14 12/26/74 23:00 0.239 27 1. 89 0.470 0.198 45 11/13/75 19: 00 0.239 28 1. 82 0.450 0.251 23 8/26/77 2:00 0.237 29 1. 75 0.430 0.345 7 9/17/78 2:00 0.234 30 1. 70 0.410 0.310 9 9/08/79 15:00 0.231 31 1. 64 0.390 0 .273 16 12/14/79 21:00 0.228 32 1. 59 0.370 0.300 12 11/21/80 11: 00 0. 226 33 1. 54 0.350 0. 407 1 10/06/81 0:00 0.223 34 1. 49 0.330 0.307 10 10/28/82 16:00 0.221 35 1. 45 0.310 0.231 31 1/03/84 1:00 0.221 36 1. 41 0 .291 0.213 41 6/06/85 22:00 0.220 37 1. 37 0 .271 0.262 18 1/18/86 16: 00 0.219 38 1. 33 0.251 0.382 3 10/26/86 0:00 0.215 39 1. 30 0.231 0.183 49 11/11/87 0:00 0.214 40 1. 27 0.211 0.237 29 8/21/89 17 :00 0.213 41 1. 24 0.191 0.407 2 1/09/90 6:00 0. 211 42 1.21 0 .171 0.382 4 11/24/90 8:00 0.203 43 1.18 0.151 0.228 32 1/27/92 15:00 0.198 44 1.15 0.131 0.166 50 11/01/92 16:00 0 .198 45 1.12 0 .111 0.189 48 11/30/93 22:00 0 .197 46 1.10 0.091 0.234 30 11 /30/94 4:00 0 .194 47 1. 08 0.071 0.268 17 2/08/96 10:00 0.189 48 1. 05 0.051 0.260 19 1/02/97 6:00 0.183 49 1. 03 0.031 0.292 13 10/04/97 15:00 0.166 50 1. 01 0.011 Computed Peaks 0. 462 100.00 0.990 Computed Peaks 0.425 50.00 0.980 Computed Peaks 0.388 25.00 0. 960 Computed Peaks 0.340 10.00 0.900 Computed Peaks 0.330 8.00 0.875 Computed Peaks 0.303 5.00 0. 800 Computed Peaks 0.249 2.00 0.500 Computed Peaks 0.214 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-50.tsf Mean= -0.884 StdDev-0. 095 Project Location:Sea-Tac Skew= 0. 562 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.130 21 2/16/49 21:00 0.210 1 89.50 0. 989 0.190 6 3/03/50 16:00 0.209 2 32 .13 0. 969 0 .127 25 2/09/51 2:00 0.196 3 19. 58 0. 949 a .115 34 10/15/51 13:00 0 .196 4 14.08 0. 929 0.105 43 3/24/53 15:00 0 .191 5 10.99 0. 909 0.123 28 12/19/53 19:00 0.190 6 9.01 0.889 • 0 .130 22 11/25/54 2:00 0 .178 7 7. 64 0.869 0.127 24 11/18/55 15:00 0 .170 8 6.63 0.849 0 .143 15 12/09/56 14:00 0.160 9 5.86 0.829 0 .131 20 12/25/57 16:00 0.158 10 5.24 0.809 0.100 47 11/03/58 17:00 0.156 11 4.75 0. 789 0.123 27 11/20/59 5:00 0 .1.54 12 4. 34 0.769 0 .110 40 2/14/61 21:00 0.150 13 3.99 0.749 0 .114 35 11/22/61 2:00 0 .149 14 3.70 0. 729 B-41 SE 144'1' Strur-.June 2007 0 .109 42 12/15/62 2:00 0.143 15 3.44 0.709 0.126 26 12/31/63 23:00 0.140 16 3.22 0.690 0 .114 36 12/21/64 4:00 0.138 17 3.03 0.670 0 .112 38 1/05/66 16: 00 0 .135 18 2.85 0.650 0 .170 8 11/13/66 19:00 0.134 19 2.70 0.630 0.191 5 8/24/68 16:00 0.131 20 2.56 0.610 0.102 44 12/03/68 16: 00 0.130 21 2.44 0.590 0 .113 37 1/13/70 22:00 0.130 22 2.32 0.570 0 .111 39 12/05/70 9:00 0.129 23 2.22 0.550 0.156 11 12/08/71 18:00 0.127 24 2.13 0.530 0.101 46 1/13/73 2:00 0.127 25 2.04 0.510 0 .116 33 11/28/73 9:00 0 .12 6 26 1. 96 0.490 0 .14 9 14 12/26/74 23:00 0.123 27 1.89 0.470 0.102 45 11/13/75 19: 00 0.123 28 1. 82 0.450 0 .12 9 23 8/26/77 2:00 0.122 29 1. 75 0.430 0 .178 7 9/17/78 2:00 0.120 30 1. 70 0.410 0 .160 9 9/08/79 15:00 0 .119 31 1. 64 0.390 0.140 16 12/14/79 21:00 0.117 32 1. 59 0.370 0.154 12 11/21/80 11: 00 0 .116 33 1.54 0.350 0.210 1 10/06/81 0:00 0 .115 34 1.49 0.330 0.158 10 10/28/82 16:00 0 .114 35 1. 45 0. 310 0 .119 31 1/03/84 1:00 0 .114 36 1.41 0.291 0 .110 41 6/06/85 22:00 0 .113 37 1. 37 0 .271 0.135 18 1/18/86 16:00 0 .112 38 1. 33 0.251 0.196 3 10/26/86 0:00 0 .111 39 1. 30 0.231 0.094 49 11/11/87 0:00 0 .110 40 1.27 0 .211 0 .122 29 8/21/89 17: 00 0 .110 41 1.24 0 .191 0.209 2 1/09/90 6:00 0.109 42 1. 21 0 .171 0 .196 4 11/24/90 8:00 0.105 43 1.18 0.151 0 .117 32 1/27/92 15:00 0.102 44 1.15 0 .131 0.086 50 11/01/92 16:00 0.102 45 1.12 0 .111 0. 097 48 11/30/93 22:00 0.101 46 1.10 0.091 0.120 30 11/30/94 4:00 0.100 47 1.08 0. 071 0.138 17 2/08/96 10:00 0.097 48 1.05 0.051 0.134 19 1/02/97 6:00 0.094 49 1. 03 0.031 0.150 13 10/04/97 15:00 0.086 50 1.01 0. 011 Computed Peaks 0.238 100.00 0.990 Computed Peaks 0.219 50.00 0.980 Computed Peaks 0.200 25.00 0. 960 Computed Peaks 0.175 10.00 0. 900 Computed Peaks 0.170 8.00 0.875 Computed Peaks 0.156 5.00 0.800 Computed Peaks 0.128 2.00 0.500 Computed Peaks 0 .110 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-52.tsf Mean= -0. 457 StdDev~ 0.118 Project Location:Sea-Tac Skew= 0.538 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.357 21 2/16/49 21:00 0.701 1 8 9. 50 0. 989 0.701 1 3/03/50 16:00 0.669 2 32.13 0. 969 0. 397 15 2/09/51 2:00 0. 592 3 19.58 0. 949 0.278 40 10/15/51 13:00 0.563 4 14.08 0. 929 0.270 45 3/24/53 15:00 0.500 5 10.99 0.909 0.335 26 12/19/53 19: 00 0.488 6 9.01 0.889 0.338 24 11/25/54 2:00 0.484 7 7. 64 0.869 0.340 23 12/20/55 17:00 0.452 8 6.63 0.849 B-42 SE }4,/' Street-June 2007 0.394 17 12/09/56 14:00 0.448 9 5. 8 6 0. 829 0.345 22 12/25/57 16: 00 0.427 10 5.24 0. 809 0.267 46 1/26/59 20:00 0.423 11 4.75 0. 7 89 0.333 27 11/20/59 5:00 0.405 12 4.34 0. 7 69 0.317 30 2/14/61 21:00 0.404 13 3.99 0. 7 49 0.289 38 11/22/61 2:00 0.402 14 3.70 0. 729 0.299 35 12/15/62 2:00 0. 397 15 3.44 0. 7 09 0.336 25 12/31/63 23:00 0.396 16 3.22 0. 690 0.295 37 12/21/64 4:00 0. 394 17 3.03 0.670 0.298 36 l / 0 5 / 66 16:00 0.389 18 2.85 0.650 0.452 8 11/13/66 19:00 0.387 19 2.70 0.630 0.488 6 8/24/68 16: 00 0.374 20 2.56 0.610 0.272 42 12/03/68 16:00 0.357 21 2.44 0. 590 0.300 34 1/13/70 22:00 0.345 22 2.32 0 .570 0.286 39 12/06/70 8:00 0.340 23 2.22 0.550 0.500 5 2/27 /72 7:00 0.338 24 2.13 0.530 0.265 47 1/13/73 2:00 0.336 25 2.04 0 .510 0. 320 28 11/28/73 9:00 0.335 26 1. 96 0. 4 90 0.423 11 12/26/74 23:00 0.333 27 1. 89 0.470 0. 271 43 12/02/75 20:00 0.320 28 1.82 0. 450 0.312 31 8/26/77 2:00 0.319 29 1. 75 0. 4 30 0.427 10 9/17/78 2:00 0 .317 30 1. 70 0. 410 0.374 20 9/08/7 9 15:00 0.312 31 1. 64 0 .3 90 0.387 19 12/14/79 21:00 0.310 32 1. 59 0.370 0.404 13 11/21/80 11: 00 0.307 33 1. 54 0. 350 0.563 4 10/06/81 0:00 0 .300 34 1. 4 9 0. 3 30 0 .396 16 10/28/82 16 :00 0.299 35 1. 4 5 0. 310 0.319 29 1/03/84 1:00 0.298 36 1. 41 0. 2 91 0.270 44 6/06/85 22:00 0.295 37 1. 37 0. 2 71 0.389 18 1/18/86 16: 00 0.289 38 1.33 0. 2 51 0. 4 84 7 10/26/86 0:00 0.286 39 1. 30 0. 2 31 0.212 49 11/11/87 0:00 0.278 40 1.27 0. 211 0.275 41 8/21/89 17:00 0. 275 41 1.24 0 .191 0.669 2 1/09/90 6:00 0.272 42 1.21 0 .1 71 0. 592 3 11/24/90 8:00 0 .271 43 1.18 0.151 0.310 32 1/27/92 15:00 0.270 44 1.15 0.131 0.199 50 11/01/92 16:00 0.270 45 1.12 0 .111 0.232 48 11/30/93 22:00 0.267 46 1.10 0. 091 0.307 33 11/30/94 4: 00 0. 2 65 47 1. 08 0. 071 0.448 9 2/08/96 10:00 0.232 48 1. 05 0.051 0.402 14 1/02/97 6:00 0.212 49 1. 03 0.031 0.405 12 10/04/97 15: 00 0.199 50 1. 01 0 .011 Computed Peaks 0. 729 100.00 0.990 Computed Peaks 0.657 50.00 0.980 Computed Peaks 0.588 25.00 0. 960 Computed Peaks 0.501 10.00 0.900 Computed Peaks 0.483 8.00 0.875 Computed Peaks 0.435 5. 00 0.800 Computed Peaks 0.341 2.00 0.500 Computed Peaks 0.283 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-54.tsf Mean= -0.367 StdDev-0 .117 Project Location:Sea-Tac Skew-0. 588 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0. 437 21 2/16/49 21:00 0.876 1 89.50 0.989 0. 876 1 3/03/50 16:00 0.818 2 32.13 0. 969 B-43 SE 144'1' Street-June 2007 0.493 14 2/09/51 2:00 0. 720 3 19.58 0. 949 0.345 40 10/15/51 13:00 0.687 4 14.08 0.929 0.332 44 3/24/53 15:00 0.622 5 10. 99 0. 909 0. 411 26 12/19/53 19:00 0.600 6 9. 01 0. 8 89 0.415 24 11/25/54 2:00 0.598 7 7. 64 0. 8 69 0.420 23 12/20/55 17:00 0.556 8 6.63 0. 849 0.480 17 12/09/56 14:00 0.552 9 5.86 0. 829 0.422 22 12/25/57 16:00 0.530 10 5.24 0. 809 0.332 45 1/26/59 20:00 0. 513 11 4.75 0. 7 89 0.407 27 11/20/59 5:00 0.498 12 4. 34 0. 7 69 0.395 28 2/14/61 21 :00 0.494 13 3.99 0. 7 4 9 0.356 38 11/22/61 2:00 0.493 14 3.70 0. 729 0.366 35 12/15/62 2:00 0. 493 15 3.44 0. 7 09 0.415 25 12/31/63 23:00 0. 488 16 3.22 0.690 0 .363 37 12/21/64 4:00 0.480 17 3.03 0.670 0.365 36 1/05/66 16:00 0.473 18 2.85 0.650 0.552 9 11/13/66 19:00 0. 470 19 2.70 0.630 0.600 6 8/24/68 16:00 0.466 20 2.56 0.610 0.333 43 12/03/68 16:00 0.437 21 2.44 0. 590 0 .367 34 1/13/70 22:00 0.422 22 2.32 0.570 0.350 39 12/06/70 8:00 0.420 23 2.22 0.550 0.622 5 2/27/72 7:00 0.415 24 2.13 0.530 0.327 47 1/13/73 2:00 0.415 25 2.04 0. 510 0.389 30 11/28/73 9.: 00 0. 411 26 1. 96 0. 4 90 0.513 11 12/26/74 23:00 0.407 27 1. 89 0. 4 70 0.332 46 12/02/75 20:00 0.395 28 1. 82 0. 4 50 0.386 31 8/26/77 2:00 0. 391 29 1. 75 0. 4 30 0.530 10 9/17 /78 2:00 0.389 30 1. 70 0.410 0. 4 66 20 9/08/79 15:00 0.386 31 1. 64 0. 3 90 0.470 19 12/14/79 21 :00 0. 379 32 1. 59 0. 3 70 0. 4 94 13 11/21/80 11 :00 0.377 33 1. 54 0. 350 0.687 4 10/06/81 0:00 0.367 34 1. 49 0.330 0.488 16 10/28/82 16:00 0.366 35 1. 45 0.310 0.391 29 3/15/84 20:00 0.365 36 1.41 0. 291 0.334 42 6/06/85 22:00 0.363 37 1. 37 0 .271 0.473 18 1/18/86 16:00 0.356 38 1. 33 0. 251 0. 5 98 7 10/26/86 0:00 0.350 39 1. 30 0.231 0.266 49 11/11/87 0:00 0.345 40 1.27 0. 211 0.345 41 8/21/89 17:00 0.345 41 1. 24 0 .191 0.818 2 1/09/90 6:00 0.334 42 1. 21 0 .171 0.720 3 11/24/90 8:00 0.333 43 1.18 0.151 0.379 32 1/27/92 15:00 0.332 44 1. 15 0.131 0 .248 50 11/01/92 16:00 0.332 45 1.12 0.111 0. 288 48 11/30/93 22:00 0.332 46 1.10 0. 091 0.377 33 11/30/94 4:00 0.327 47 1. 08 0.071 0. 556 8 2/08/96 10:00 0. 288 48 1. 05 0.051 0. 498 12 1/02/97 6:00 0.266 49 1. 03 0.031 0. 493 15 10/04/97 15:00 0.248 50 1. 01 0. 011 Computed Peaks 0.902 100.00 0.990 Computed Peaks 0. 811 50.00 0.980 Computed Peaks 0. 724 25.00 0. 960 Computed Peaks 0.615 10.00 0.900 Computed Peaks 0.593 8.00 0. 87 5 Computed Peaks 0.534 5.00 0. 800 Computed Peaks 0.419 2.00 0. 500 Computed Peaks 0. 349 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-60.tsf Mean= -0. 876 StdDev= 0. 096 Project Location:Sea-Tac Skew= 0.561 B-44 SE 144'~ Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.133 21 2/16/49 21:00 0.214 1 89.50 0.989 0.193 6 3/03/50 16: 00 0.213 2 32.13 0.969 0.129 25 2/09/51 2:00 0.201 3 19.58 0.949 0 .117 34 10/15/51 13 :00 0.200 4 14.08 0.929 0.107 43 3/24/53 15:00 0.195 5 10.99 0.909 0.125 27 12/19/53 19: 00 0.193 6 9.01 0.889 0.133 22 11/25/54 2:00 0.181 7 7. 64 0.869 0.130 24 11/18/55 15:00 0.173 8 6.63 0.849 0.146 15 12/09/56 14:00 0 .163 9 5.86 0.829 0 .133 20 12/25/ 57 16: 00 0 .162 10 5.24 0.809 0.102 47 11/03/58 17:00 0.159 11 4.75 0.789 0.125 28 11/20/59 5:00 0.157 12 4.34 0. 7 69 0 .112 40 2/14/61 21:00 0.153 13 3.99 0.749 0.116 35 11/22/61 2:00 0.152 14 3.70 0.729 0 .111 42 12/15/62 2:00 0.146 15 3.44 0. 709 0.128 26 12/31/63 23:00 0.143 16 3.22 0. 690 0 .116 36 12/21/64 4: 00 0.140 17 3.03 0.670 0 .115 38 1/05/66 16:00 0.138 18 2.85 0.650 0.173 8 11/13/66 19:00 0.137 19 2.70 0.630 0.195 5 8/24/68 16: 00 0.133 20 2.56 0.610 0.104 44 12/03/68 16: 00 0.133 21 2.44 0.590 0 .116 37 1/13/70 22:00 0.133 22 2.32 0.570 0 .113 39 12/05/70 9:00 0.132 23 2.22 0.550 0.159 11 12/08/71 18:00 0 .130 24 2.13 0.530 0.103 46 1/13/73 2:00 0.129 25 2.04 0.510 0 .118 33 11/28/73 9:00 0.128 26 1. 96 0. 4 90 0.152 14 12/26/74 23:00 0.125 27 1. 89 0.470 0.104 45 11/13/75 19: 00 0.125 28 1. 82 0.450 0.132 23 8/26/77 2:00 0.124 29 1. 75 0.430 0.181 7 9/17/78 2:00 0.123 30 1. 70 0.410 0.163 9 9/08/79 15:00 0 .121 31 1. 64 0. 390 0.143 16 12/14/79 21:00 0.120 32 1.59 0.370 0.157 12 11/21/80 11 :00 0 .118 33 1.54 0.350 0.214 1 10/06/81 0:00 0.117 34 1.49 0.330 0.162 10 10/28/82 16: 00 0.116 35 1.45 0.310 0.121 31 1/03/84 1:00 0.116 36 1. 41 0.291 0 .112 41 6/06/85 22:00 0.116 37 1. 37 0.271 0.138 18 1/18/86 16:00 0 .115 38 1.33 0.251 0.201 3 10/26/86 0:00 0 .113 39 1.30 0.231 0. 096 49 11/11/87 0:00 0.112 40 1.27 0.211 0.124 29 8/21/89 17:00 0.112 41 1.24 0.191 0 .213 2 1/09/90 6:00 0 .111 42 1. 21 0 .171 0.200 4 11/24/90 8:00 0.107 43 1.18 0.151 0.120 32 1/27/92 15:00 0.104 44 1.15 0 .131 0.087 50 11/01/92 16:00 0.104 45 1.12 0 .111 0. 0 99 48 11/30/93 22:00 0.103 46 1.10 0.091 0.123 30 11/30/94 4:00 0 .102 47 1. 08 0.071 0.140 17 2/08/96 10:00 0.099 48 1. 05 0.051 0.137 19 1/02/97 6:00 0.096 49 1. 03 0.031 0.153 13 10/04/97 15:00 0.087 50 1. 01 0. 011 Computed Peaks 0.243 100.00 0.990 Computed Peaks 0.223 SO.DO 0. 980 Computed Peaks 0.204 25.00 0. 960 Computed Peaks 0.178 10.00 0.900 Computed Peaks 0.173 8.00 0.875 Computed Peaks 0.159 5.00 0.800 B-45 SE U(h Srreel -June2007 Computed Peaks 0.130 2.00 0.500 Computed Peaks 0.112 1.30 o .231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-70.tsf Mean= -0.327 StdDev-0 .133 Project Location:Sea-Tac Skew= 0.509 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.492 20 2/16/49 21:00 1. 06 1 89.50 o. 989 1. 06 1 3/03/50 16:00 0.988 2 32 .13 0.969 0.578 11 2/09/51 2:00 0. 861 3 19.58 0. 94 9 0.353 45 1/30/52 8:00 0.781 4 14.08 0.929 0.354 44 3/24/53 15:00 0. 729 5 10.99 0.909 0.454 25 12/19/53 19:00 0.667 6 9.01 0.889 0.470 22 2/07/55 17:00 0.635 7 7. 64 0.869 0.485 21 12/20/55 17:00 0.610 B 6.63 0.849 0.549 16 12/09/56 14:00 0.607 9 5.86 0.829 0.462 23 12/25/57 16:00 0.604 10 5.24 0. 809 0.361 42 1/26/59 20:00 0.578 11 4.75 0.789 0.461 24 11/20/59 5:00 0.568 12 4.34 0.769 0.432 30 2/14/61 21:00 0.562 13 3.99 0. 74 9 0.376 39 11/22/61 2:00 0.557 14 3.70 0.729 o .411 32 12/15/62 2:00 0.551 15 3.44 0.709 0.451 26 12/31/63 23:00 o. 54 9 16 3.22 0.690 0.389 37 12/21/64 4:00 0.540 17 3.03 0. 670 0.402 34 1/05/66 16:00 0. 536 18 2.85 0. 650 0.610 8 11/13/66 19:00 0.508 19 2.70 0.630 o. 635 7 8/24/68 16:00 0. 492 20 2.56 0. 610 0.371 41 12/03/68 16:00 0.485 21 2.44 0.590 0.405 33 1/13/70 22:00 0.470 22 2.32 0.570 0. 396 36 12/06/70 8:00 0 .462 23 2.22 0.550 0. 729 5 2/27 /72 7:00 0.461 24 2.13 0.530 0.355 43 1/13/73 2:00 0. 454 25 2.04 0.510 0.441 28 11/28/73 9:00 0.451 26 1. 96 0.490 0.604 10 12/26/74 23:00 0.450 27 1. 89 0.470 0.373 40 12/02/75 20:00 0.441 28 1. 82 0.450 0.385 38 8/26/77 2:00 0.436 29 1. 75 0.430 0.557 14 9/22/78 19:00 0.432 30 1. 70 0.410 0 .450 27 9/08/79 15:00 0.416 31 1. 64 0.390 0.536 18 12/14/79 21 :00 0.411 32 1. 59 0.370 0.540 17 11/21/80 11: 00 0. 405 33 1. 54 0.350 0.781 4 10/06/81 15:00 0. 402 34 1. 49 0.330 0.508 19 10/28/82 16:00 0. 401 35 1. 45 0.310 0.436 29 3/15/84 20:00 0.396 36 1. 41 0.291 0.340 46 6/06/85 22:00 o. 389 37 1. 37 0.271 0.562 13 1/18/86 16:00 0.385 38 1. 33 0.251 0. 607 9 10/26/86 0: 00 0. 37 6 39 1. 30 0.231 0 .267 49 1/14/88 0: 00 0.373 40 1.27 0. 211 0.321 47 8/21/89 17:00 0.371 41 1. 24 0.191 0.988 2 1/09 / 90 6:00 0. 361 42 1.21 0 .171 0. 8 61 3 11/24/90 8:00 0.355 43 1.18 0.151 0.416 31 1/27/92 15:00 0. 354 44 1.15 0.131 0.249 50 12/10/92 6:00 0.353 45 1.12 0 .111 0.283 48 11/30/93 22:00 0. 340 46 1.10 0. 091 0. 401 35 11/30/94 '4:00 0.321 47 1. 08 0. 071 0.667 6 2/08/96 10:00 0.283 48 1. 05 0.051 0.568 12 1/02/97 6:00 0.267 49 1. 03 0.031 0.551 15 10/04/97 15:00 0. 24 9 50 1. 01 0. 011 B-46 SE 144"' Street-June 2007 Computed Peaks 1.08 100.00 0.990 Computed Peaks 0.958 50.00 0. 980 Computed Peaks 0.847 25.00 0. 960 Computed Peaks 0.707 10.00 0.900 Computed Peaks 0. 680 8.00 0.875 Computed Peaks 0.604 5.00 0.800 Computed Peaks 0.459 2.00 0.500 Computed Peaks 0.371 1. 30 0. 2 31 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-80.tsf Mean= 0.090 StdDev= 0 .131 Project Location:Sea-Tac Skew= 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.34 18 2/16/49 21: 00 2. 61 l 89.50 0.989 2.57 2 3/03/50 16: 00 2. 57 2 32.13 0. 969 1. 51 11 2/09/51 2:00 2.31 3 19.58 0.949 0.958 41 1/30/52 8:00 2.05 4 14.08 0. 929 0. 92 6 44 3/24/53 15:00 1. 84 5 10.99 0. 909 1.19 25 12/19/53 19:00 1. 77 6 9.01 0. 889 1. 2 8 21 2/07/55 17:00 1. 65 7 7. 64 0. 869 1. 30 20 12/20/55 17:00 1. 59 8 6.63 0. 849 1. 4 8 13 12/09/56 14:00 1. 58 9 5.86 0.829 1.20 24 12/25/57 16.: 00 1. 53 10 5. 24 0. 809 0.915 45 1/26/59 20:00 1. 51 11 4.75 0. 789 1. 2 4 23 11/20/59 5:00 1. 51 12 4.34 0. 7 69 1. 09 31 2/14/61 21:00 1. 48 13 3.99 0. 7 4 9 0.938 43 11/22/61 2:00 1.47 14 3.70 0.729 1. 08 32 12/15/62 2:00 1. 41 15 3.44 0.709 1.19 26 12/31/63 23:00 1. 38 16 3.22 0.690 1. 02 37 12/21/64 4:00 1. 36 17 3.03 0.670 1. 08 34 1/05/66 16:00 1. 34 18 2.85 0.650 1. 51 12 11/13/66 19:00 1. 34 19 2.70 0.630 1. 59 8 8/24/68 16:00 1. 30 20 2.56 0.610 1. 01 39 12/03/68 16:00 1.28 21 2.44 0.590 1. 08 33 1/13/70 22:00 1.27 22 2.32 0.570 1. 05 35 12/06/70 8:00 1.24 23 2 .22 0.550 1. 84 5 2/27 /72 7:00 1.20 24 2.13 0.530 0.954 42 1/13/73 2:00 1.19 25 2. 04 0. 510 1. 14 28 11/28/73 9:00 1.19 26 1. 96 0. 4 90 1. 65 7 12/26/74 23:00 1.15 27 1. 89 0. 470 1. 02 36 12/02/75 20:00 1.14 28 1. 82 0. 450 0.972 40 B/26/77 2:00 1.14 29 1. 75 0.430 1. 38 16 9/22/78 19:00 1.10 30 1. 70 0.410 1. 14 29 9/08/79 15:00 1. 09 31 1. 64 0.390 1. 41 15 12/14/79 21: 00 1. 08 32 1. 59 0.370 1. 34 19 11/21/80 11: 00 1. 08 33 1. 54 0.350 2.05 4 10/06/81 15:00 1. 08 34 1. 49 0.330 1. 27 22 10/28/82 16: 00 1. 05 35 1. 45 0.310 1.15 27 1/03/84 1:00 1. 02 36 1. 41 0 .291 0.858 46 6/06/B5 22:00 1. 02 37 1. 37 0.271 1. 58 9 1/18/86 16:00 1. 02 38 1. 33 0.251 1.53 10 10/26/86 0:00 1. 01 39 1. 30 0.231 0. 707 49 1/14/88 12:00 0. 972 40 1.27 0.211 0. 815 47 8/21/89 17:00 0.958 41 1. 24 0.191 2. 61 1 1/09/90 6:00 0.954 42 1. 21 0 .171 2.31 3 11/24/90 8:00 0.938 43 1.18 0.151 1.10 30 1/27/92 15:00 0. 92 6 44 1.15 0.131 B-47 SE 14¢" Street -June 2007 0. 692 50 3/22/93 22:00 0 .. 915 45 1.12 0.111 0. 717 48 11/30/93 22:00 0.858 46 1.10 0. 091 1.02 38 11/30/94 4:00 0.815 47 1. 08 0.071 1. 77 6 2/08/96 10:00 0.717 48 1.05 0.051 1. 4 7 14 1/02/97 6:00 0.707 49 1. 03 0.031 1.36 17 10/04/97 15:00 0. 692 50 1. 01 0.011 Computed Peaks 2. 76 100.00 0.990 Computed Peaks 2.47 50.00 0.980 Computed Peaks 2.19 25.00 D. 9 60 Computed Peaks 1. 83 10.00 0.900 Computed Peaks 1. 76 8.00 0.875 Computed Peaks 1.57 5.00 0. 800 Computed Peaks 1.20 2.00 0 .500 Computed Peaks 0.973 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-90.tsf Mean= -0.989 StdDev= 0.096 Project Location:Sea-Tac Skew~ 0.559 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.102 21 2/16/49 21:00 0.164 1 89. 50 0.989 0.148 6 3/03/50 16:00 0.164 2 32.13 0.969 0.099 25 2/09/51 2:00 0.155 3 19.58 0.949 0.090 34 10/15/51 13:00 0.155 4 14.08 0.929 0.082 43 3/24/53 15:00 0.150 5 10.99 0. 909 0.096 28 12/19/53 19:00 0.148 6 9.01 0. 889 0.102 22 11/25/54 2:00 0.139 7 7.64 0.869 0.100 24 11/18/55 15:00 0 .133 · 8 6.63 0.849 0.112 15 12/09/56 14:00 0.125 9 5.86 0.829 0.103 20 12/25/57 16:00 0.124 10 5.24 0. 809 0.078 47 11/03/58 17:00 0.123 11 4.75 0.789 0.097 27 11/20/59 5:00 0.121 12 4.34 0. 7 69 0.086 40 2/14/61 21:00 0.118 13 3.99 0.749 0.090 35 11/22/61 2:00 0.117 14 3.70 0. 72 9 0.085 42 12/15/62 2:00 0.112 15 3.44 0. 709 0.099 26 12/31/63 23:00 0.110 16 3.22 0.690 0.089 36 12/21/64 4:00 0.108 17 3.03 0. 670 0.088 38 1/05/66 16:00 0.106 18 2.85 0.650 0.133 8 11/13/66 19:00 0.105 19 2.70 0.630 0.150 5 8/24/68 16:00 0.103 20 2.56 0.610 0.080 44 12/03/68 16:00 0.102 21 2.44 0.590 0.089 37 1/13/70 22:00 0.102 22 2.32 0.570 0.087 39 12/05/70 9:00 0.101 23 2.22 0.550 0 .123 11 12/08/71 18:00 O .100 24 2 .13 0.530 0.080 46 1/13/73 2:00 0 .099 25 2.04 0.510 0.091 33 11/28/73 9:00 0.099 26 1.96 0.490 0.117 14 12/26/74 23:00 0.097 27 1.89 0.470 0.080 45 11/13/75 19:00 0.096 28 1. 82 0. 450 0.101 23 8/26/77 2:00 0.095 29 1. 75 0.430 0 .139 7 9/17 /78 2:00 0.095 30 1. 70 0.410 0.125 9 9/08/79 15:00 0.093 31 1. 64 0.390 0.110 16 12/14/79 21:00 0. 092 32 1. 59 0.370 0.121 12 11/21/80 11 :00 0. 091 33 1. 54 0.350 0. 164 1 10/06/81 0:00 0.090 34 1. 49 0.330 0 .124 10 10/28/82 16:00 0.090 35 1. 45 0.310 0. 093 31 1/03/84 1:00 0.089 36 1. 41 0. 291 0.086 41 6/06/85 22:00 0.089 37 1. 37 0.271 0.106 18 1/18/86 16:00 0.088 38 1. 33 0.251 B-48 SE 144"' S1reer-June 2007 0.155 3 10/26/86 0:00 0.087 39 1. 30 0 .231 0.074 49 11/11/87 0:00 0.086 40 1. 27 0.211 0.095 29 8/21/89 17:00 0.086 41 1. 24 0 .191 0.164 2 1/09/90 6:00 0.085 42 1. 21 0.171 0.155 4 11/24/90 8:00 0.082 43 1.18 0.151 0 .092 32 1/27/92 15:00 0.080 44 1.15 0.131 0.067 50 11/01/92 16: 00 0.080 45 1.12 0 .111 0.076 48 11/30/93 22:00 0.080 46 1.10 0. 0 91 0.095 30 11/30/94 4:00 0.078 47 1. 08 0. 071 0.108 17 2/08/96 10:00 0.076 48 1. 05 0.051 0.105 19 1/02/97 6:00 0.074 49 1. 03 0.031 0 .118 13 10/04/97 15:00 0.067 50 1. 01 0. 011 Computed Peaks 0.187 100.00 0.990 Computed Peaks 0.172 50.00 0.980 Computed Peaks 0.157 25.00 0. 960 Computed Peaks 0.137 10.00 0.900 Computed Peaks 0.133 8.00 0.875 Computed Peaks 0.122 5.00 0.800 Computed Peaks 0.100 2.00 0.500 Computed Peaks 0.086 1. 30 0. 2 31 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-100.tsf Mean= -1.001 StdDev= 0.167 Project Location:Sea-Tac Skew= 0.401 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0 .113 18 2/16/49 21 :00 0.250 1 89.50 0.989 0.250 1 3/03/50 16:00 o. 24 9 2 32.13 0. 969 0.138 9 2/09/51 2:00 0.216 3 19.58 0.949 0.078 38 1/30/52 8:00 0.188 4 14.08 0.929 0.069 42 3/24/53 15:00 0.169 5 10.99 0.909 0.096 23 12/19/53 19: 00 0.169 6 9.01 0.889 0.113 19 2/07/55 17:00 0.149 7 7. 64 0.869 0 .117 16 12/20/55 17: 00 0.147 8 6.63 0.849 0.127 13 12/09/56 14:00 0.138 9 5.86 0. 829 0.094 25 12/25/57 16:00 0 .132 10 5.24 0.809 0.073 41 1/26/59 20: 00 0.129 11 4.75 0.789 0.121 14 11/20/59 21: 00 0.129 12 4.34 0.769 0.088 31 2/14/61 21:00 0.127 13 3.99 0.749 0.068 43 11/22/61 2:00 0.121 14 3.70 0.729 0. 091 28 12 /15 / 62 2:00 0.120 15 3.44 0.709 0.094 26 12/31/63 23:00 0 .117 16 3.22 0.690 0.077 39 12/21/64 4:00 0.115 17 3.03 0.670 0.086 34 1/05/66 16:00 0.113 18 2.85 0.650 0.129 11 1/19/67 14:00 0.113 19 2.70 0.630 0 .115 17 B/24/68 16: 00 0.111 20 2.56 0.610 0.084 36 12/03/68 16: 00 0.105 21 2.44 0.590 0.088 32 1/13/70 22: 00 0.105 22 2.32 0.570 0.089 29 12/06/70 8: 00 0.096 23 2.22 0.550 0.169 5 2/27 /72 7:00 0.096 24 2.13 0.530 0.075 40 1/13/73 2:00 0.094 25 2.04 0.510 0.096 24 11/28/73 9:00 0.094 26 1. 96 0.490 0 .14 9 7 12/26/74 23:00 0.093 27 1. 89 0.470 0.086 35 12/02/75 20:00 0.091 28 1. 82 0.450 0.060 45 8/26/77 2:00 0.089 29 1. 75 0.430 0.105 21 9/22/78 19:00 0.088 30 1. 70 0.410 0.064 44 9/08/79 15:00 0.088 31 1. 64 0.390 0.120 15 12/14/79 21:00 0.088 32 1. 59 0.370 B-49 SE J4¢h Srree1-June 2007 0.105 22 11/21/80 11:00 0.087 33 1. 54 0.350 0.188 4 10/06/81 15:00 0.086 34 1. 49 0.330 0.088 30 10/28/82 16: 00 0.086 35 1. 45 0.310 0.093 27 1/03/84 1:00 0.084 36 1. 41 0.291 0.056 48 6/06/85 22:00 0.081 37 1. 37 0. 271 0.147 8 1/18/86 16:00 0.078 38 1. 33 0.251 0.132 10 11/24/86 3:00 0.077 39 1. 30 0.231 0.059 47 1/14/88 12:00 0. 075 40 1.27 0 .211 0.055 49 11/05/88 14:00 0.073 41 1.24 0.191 0.249 2 1/09/90 6:00 0.069 42 1.21 0 .171 0.216 3 11/24/90 8: 00 0. 068 43 1.18 0.151 0.087 33 1/27 /92 15:00 0. 064 44 1.15 0 .131 0.060 46 3/22/93 22:00 0.060 45 1.12 0 .111 0. 04 3 50 11/30/93 22:00 0. 060 46 1. 10 0.091 0.081 37 12/27 /94 1:00 0. 059 47 1. 08 0.071 0.169 6 2/08/96 10:00 0.056 48 1. 05 0.051 0.129 12 1/02/97 6:00 o. 055 49 1. 03 0.031 0 .111 20 10/04/97 15:00 0.043 50 1. 01 0. 011 Computed Peaks 0.273 100.00 0.990 Computed Peaks 0 .239 50.00 0.980 Computed Peaks 0.206 25.00 0. 960 Computed Peaks 0.166 10.00 0.900 Computed Peaks 0.158 8.00 0.875 Computed Peaks 0.137 5.00 0.800 Computed Peaks 0. 097 2.00 0.500 Computed Peaks 0.074 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-106.tsf Mean= 0.164 StdDev~ 0.122 Project Location:Sea-Tac Skew= 0 .511 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 52 20 2/16/49 21:00 3.02 1 89.50 0.989 3.02 1 3/03/50 16:00 2.88 2 32.13 0. 969 1. 73 12 2/09/51 2:00 2.54 3 19. 58 0. 94 9 1.13 42 10/15/51 13:00 2.29 4 14 .08 0. 929 1.12 44 3/24/53 15:00 2 .15 5 10.99 0. 909 1. 40 27 12/19/53 19: 00 1. 98 6 9.01 0.889 1. 44 23 2/07/55 17:00 1. 98 7 7.64 0.869 1. 47 22 12/20/55 17:00 1. 96 8 6.63 0. 849 1. 67 15 12/09/56 14:00 1. 84 9 5.86 0. 829 1. 43 24 12/25/57 16:00 1. 80 10 5.24 0.809 1.12 43 1/26/59 20:00 1. 73 11 4.75 0.789 1. 41 25 11/20/59 5:00 1. 7 3 12 4.34 0.769 1. 33 29 2/14/61 21:00 1. 72 13 3.99 0.749 1.17 39 11/22/61 2:00 1. 70 14 3.70 0.729 1. 25 34 12/15/62 2:00 1. 67 15 3.44 0.709 1. 41 26 12/31/63 23:00 1. 65 16 3.22 0. 690 1.22 37 12/21/64 4:00 1. 65 17 3.03 0.670 1. 25 36 1/05/66 16:00 1. 62 18 2.85 0.650 1. 84 9 11/13/66 19:00 1. 61 19 2.70 0. 630 1. 98 6 8/24/68 16:00 1. 52 20 2.56 0. 610 1.15 41 12/03/68 16: 00 1.51 21 2.44 0.590 1. 26 33 1/13/70 22:00 1. 47 22 2.32 0.570 1. 20 38 12/06/70 8:00 1. 44 23 2.22 0.550 2 .15 5 2/27/72 7:00 1. 43 24 2.13 0.530 1.12 45 1/13/73 2:00 1. 41 25 2.04 0.510 1. 33 30 11/28/73 9: 00 1. 41 26 1. 96 0. 4 90 B-50 SE J4¢h Streer-June 2007 1.80 10 12/26/74 23:00 1. 40 27 1. 89 0.470 1.16 40 12/02/75 20:00 1. 34 28 1. 82 0. 450 1.26 32 8/26/77 2:00 1. 33 29 1. 75 0. 430 1. 73 l] 9/17 /78 2:00 1. 33 30 1. 70 0. 410 1. 51 21 9/08/79 15:00 1. 29 31 1. 64 0 .390 1. 62 18 12/14/79 21: 00 1. 26 32 1. 59 0.370 1. 65 16 11/21/80 11: 00 1. 26 33 1. 54 o. 350 2 .29 4 10/06/81 0:00 1.25 34 1. 4 9 0.330 1. 61 19 10/28/82 16:00 1. 25 35 1. 45 0.310 1. 34 28 1/03/84 1:00 1. 25 36 1. 41 o .2 91 1.10 47 6/06/85 22:00 1. 22 37 1.37 o. 271 1. 70 14 1/18/86 16:00 1. 20 38 1. 33 0.251 1. 96 8 10/26/86 0:00 1.17 39 1. 30 0. 231 0.857 49 11/11/87 0:00 1.16 40 1. 27 0.211 1.11 46 8/21/89 17:00 1.15 41 1. 24 0 .191 2.88 2 1/09/90 6:00 1.13 42 1. 21 0.171 2.54 3 11/24/90 8:00 1.12 43 1.18 0 .151 1. 29 31 1/27/92 15:00 1.12 44 1.15 0.131 0.804 50 11/01/92 16:00 1.12 45 1.12 0.111 0.937 48 11/30/93 22:00 1.11 46 1.10 o. 091 1. 25 35 11/30/94 4:00 1.10 47 1. 08 0.071 1. 98 7 2/08/96 10:00 0.937 48 1. 05 0.051 1. 72 13 1/02/97 6:00 0.857 49 1. 03 0.031 1. 65 17 10/04/97 15:00 0.804 50 1. 01 o. 011 Computed Peaks 3.10 100.00 0.990 Computed Peaks 2.79 50.00 0.980 Computed Peaks 2.49 25.00 O. 960 Computed Peaks 2 .11 10.00 0.900 Computed Peaks 2.04 8.00 0. 875 Computed Peaks 1. 83 5.00 0.800 Computed Peaks 1. 42 2. 00 0.500 Computed Peaks 1.17 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-110. tsf Mean= 0.487 StdDev= 0.145 Project Location:Sea-Tac Skew= 0. 484 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 3.35 20 2/16/49 21:00 6. 91 1 89.50 0.989 6.79 2 3/03/50 16:00 6. 7 9 2 32.13 0. 969 3.89 9 2/09/51 2:00 6.11 3 19.58 0. 949 2.38 40 1/30/52 8:00 5.57 4 14.08 o. 929 2.21 44 3/24/53 15:00 4.75 5 10.99 0.909 2. 95 25 12/19/53 19:00 4.66 6 9.01 0.889 3.27 22 2/07/55 17:00 4.31 7 7.64 0.869 3.34 21 12/20/55 17:00 4.16 8 6.63 o. 849 3.77 13 12/09/56 14:00 3.89 9 5.86 0.829 2. 95 24 12/25/57 16:00 3.86 10 5.24 0.809 2.22 43 1/26/59 20:00 3.82 l] 4.75 o. 78 9 3.38 19 11/20/59 21:00 3.80 12 4.34 0.769 2.65 34 2/14/61 21:00 3.77 13 3.99 o. 74 9 2.27 42 11/22/61 2:00 3.74 14 3.70 o. 729 2.73 29 12/15/62 2:00 3. 61 15 3.44 0.709 2. 91 26 12/31/63 23:00 3.49 16 3.22 0.690 2.47 37 12/21/64 4:00 3.47 17 3.03 0. 670 2.66 33 1/05/66 16:00 3.41 18 2.85 0.650 3.86 10 11/13/66 19:00 3.38 19 2.70 0.630 3.80 12 8/24/68 16:00 3.35 20 2.56 0.610 B-51 SE 144"' Street-June 2007 2.54 36 12/03/68 16:00 3.34 21 2.44 0. 590 2.70 32 1/13/70 22:00 3.27 22 2.32 0. 570 2.70 31 12/06/70 8:00 3.02 23 2.22 0.550 4.75 5 2/27/72 7:00 2.95 24 2.13 0. 530 2.34 41 1/13/73 2:00 2.95 25 2.04 0. 510 2.88 27 11/28/73 9:00 2.91 26 I. 96 0. 490 4.31 7 12/26/74 23:00 2.88 27 1. 89 0 .470 2.58 35 12/02/75 20:00 2.85 28 I. 82 0. 450 2.19 45 8/2 6/77 2:00 2.73 29 I. 75 0. 430 3. 4 7 17 9/22/78 19:00 2.71 30 I. 70 0.410 2.46 39 9/08/79 15:00 2.70 31 I. 64 0.390 3.61 15 12/14/79 21:00 2.70 32 I. 59 0. 370 3.41 18 11/21/80 11: 00 2.66 33 I. 54 0. 350 5.57 4 10/06/81 15:00 2. 65 34 I. 4 9 0. 330 3.02 23 10/28/82 16:00 2.58 35 I. 45 D.310 2. 85 28 1/03/84 1:00 2.54 36 1. 41 0.291 I. 97 46 6/06/85 22:00 2.47 37 I. 37 D .271 4.16 8 1/18/86 16:00 2.47 38 I. 33 0. 251 3. 82 11 11/24/86 3:00 2. 4 6 39 I. 30 0.231 1. 79 48 1/14/88 12:00 2.38 40 I. 27 0.211 1. 87 47 11/05/88 14:00 2.34 41 1. 24 0 .191 6. 91 I 1/09/90 6:00 2.27 42 I. 21 0.171 6.11 3 11/24/90 8:00 2.22 43 1.18 0 .151 2.71 30 1/27/92 15:00 2.21 44 1.15 0 .131 1. 77 49 3/22/93 22:00 2 .19 45 1.12 0 .111 I. 58 50 11/30/93 22:00 1. 97 46 1.10 0. 0 91 2.47 38 11/30/94 4:00 1. 87 47 1. 08 0.071 4.66 6 2/08/96 ID: 00 1. 79 48 I. 05 0.051 3.74 14 1 / 02 I 97 6:00 1. 77 49 1. 03 0.031 3. 49 16 10/04/97 15:00 I. 58 50 1. 01 a. 011 Computed Peaks 7. 4 6 100. 00 0.990 Computed Peaks 6.60 50.00 0.980 Computed Peaks 5.78 25.00 0. 960 Computed Peaks 4.76 10.00 0.900 Computed Peaks 4.56 8.00 0.875 Computed Peaks 4.01 5.00 0.800 Computed Peaks 2.99 2.00 0.500 Computed Peaks 2.37 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-120.tsf Mean= -0.565 StdDev-0.101 Project Location:Sea-Tac Skew:e: 0.475 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0. 2 77 21 2/16/49 21:00 0.467 1 89.50 0.989 0.426 4 3/03/50 16:00 0.443 2 32.13 o. 969 0.280 20 2/09/51 2:00 0.434 3 19.58 0.949 0. 231 38 10/15/51 13:00 0.426 4 14. 08 0. 929 0.214 45 3/24/53 15:00 0.391 5 10.99 0.909 0.258 27 12/19/53 19:00 0.386 6 9. 01 0.889 0. 272 23 11/25/54 2:00 0.355 7 7. 64 0.869 0 .262 25 11/18/55 15:00 0.351 8 6.63 0.849 0.306 16 12/09/56 14:00 0.336 9 5.86 0. 829 0.272 22 12/25/57 16:00 0.324 10 5.24 0.809 0. 208 47 11/18/58 13:00 0.322 11 4.75 0.789 0. 2 64 24 11/20/59 5: 00 0.320 12 4.34 0.769 0.230 39 2/14/61 21:00 0.315 13 3.99 0.749 0.232 37 11/22/61 2:00 0. 313 14 3.70 0. 729 B-52 SE I 44'h Street-June 2007 0.230 40 12/15/62 2:00 0.313 15 3.44 0.709 0.262 26 12/31/63 23:00 0.306 16 3.22 0.690 0.235 36 12/21/64 4:00 0.300 17 3.03 0.670 0.236 35 1/05/66 16:00 0.298 18 2.85 0.650 0.355 7 11/13/66 19: 00 0. 2 90 19 2.70 0.630 0.386 6 8/24/68 16:00 0. 2 80 20 2.56 0.610 0.217 43 12/03/68 16:00 0.277 21 2.44 0.590 0.238 34 1/13/70 22:00 0.272 22 2.32 0.570 0.227 41 12 / 0 5 /7 0 9:00 0. 272 23 2.22 0.550 0.336 9 2/27/72 7:00 0. 2 64 24 2.13 0.530 0.214 46 1/13/73 2:00 0. 2 62 25 2.04 0.510 0.243 32 11/28/73 9:00 0. 2 62 26 1. 96 0. 4 90 0.324 10 12/26/74 23:00 0.258 27 1.89 0.470 0. 216 44 12/02/75 20:00 0.258 28 1. 82 0.450 0.258 28 8/26/77 2:00 0.249 29 1. 75 0.430 0.351 8 9/17 /78 2: 00 0.247 30 1. 70 0.410 0.315 13 9/08/79 15:00 0.244 31 1. 64 0.390 0.298 18 12/14/79 21:00 0.243 32 1. 59 0.370 0.322 11 11/21/80 11: 00 0.239 33 1.54 0.350 0.443 2 10/06/81 0:00 0.238 34 1. 4 9 0.330 0.320 12 10/28/82 16:00 0.236 35 1. 45 0.310 0.249 29 1/03/84 1:00 0.235 36 1. 41 0. 2 91 0.220 42 6/06/85 22:00 0.232 37 1. 37 0. 271 0.300 17 1/18/86 16:00 0.231 38 1.33 0.251 0.391 5 10/26/86 0:00 0.230 39 1. 30 0.231 0.185 49 11/11/87 0:00 0.230 40 1.27 0. 211 0.239 33 8/21/89 17:00 0.227 41 1. 24 0 .191 0.467 1 1/09/90 6:00 0.220 42 1.21 0 .171 0.434 3 11/24/90 8:00 0. 217 43 1.18 0.151 0.244 31 1/27/92 15:00 0.216 44 1.15 0.131 0.169 50 11/01/92 16:00 0.214 45 1.12 0 .111 0.193 48 11/30/93 22:00 0.214 46 1.10 0.091 0.247 30 11/30/94 4:00 0. 208 47 1. 08 0.071 0.313 15 2/08/96 10:00 0.193 48 1. 05 0.051 0.290 19 1/02/97 6:00 0.185 49 1. 03 0.031 0.313 14 10/04/97 15:00 0.169 50 1. 01 0. 011 Computed Peaks 0.508 100.00 0. 990 Computed Peaks 0.466 50.00 0.980 Computed Peaks 0.425 25. 00 0. 960 Computed Peaks 0.371 10.00 0.900 Computed Peaks 0.360 8.00 0.875 Computed Peaks 0.329 5.00 0.800 Computed Peaks 0.268 2.00 0.500 Computed Peaks 0.227 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-130.tsf Mean= 0.015 StdDev-0.175 Project Location:Sea-Tac Skew= 0.324 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.16 19 2/16/49 21:00 2.64 1 89.50 0. 989 2. 64 1 3/03/50 16:00 2.63 2 32.13 0. 969 1.47 9 2/09/51 14:00 2.28 3 19.58 0.949 0. 811 38 1/30/52 8: 00 2.05 4 14. 08 0.929 0. 694 43 3/24/53 15:00 1. 79 5 10.99 0. 909 0.990 23 12/19/53 19:00 1. 77 6 9.01 0.889 1.18 17 2/07/55 17:00 1. 57 7 7. 64 0. 869 1.22 16 12/20/55 17:00 1. 55 8 6.63 0. 849 B-53 SE 144"' Street-June 2007 1.33 13 12/09/56 14:00 1. 4 7 9 5.86 0.829 0. 967 25 12/25/57 16:00 1. 41 10 5.24 0.809 0.740 41 1/26/59 20:00 1. 35 11 4.75 0.789 1.31 14 11/20/59 21:00 1. 34 12 4.34 0.769 0.894 34 2/14/61 21:00 1. 33 13 3.99 0.749 0. 697 42 11/22/61 2:00 1. 31 14 3.70 0.729 0. 940 29 12/15/62 2: 00 1.26 15 3. 44 0.709 0. 961 26 12/31/63 23:00 1.22 16 3.22 0.690 0.788 39 12/21/64 4: 00 1.18 17 3.03 0.670 0 .892 35 1/05/66 16:00 1.17 18 2.85 0.650 1.35 11 1/19/67 14: 00 1.16 19 2.70 0.630 1.16 20 8/24/68 16: 00 1.16 20 2.56 0.610 0.869 36 12/03/68 16: 00 1.11 21 2.44 0.590 0. 908 30 1/13/70 22 :00 1.11 22 2. 32 0.570 0. 943 28 12/06/70 8:00 0.990 23 2.22 0.550 1. 77 6 2/27 /72 7:00 0.984 24 2 .13 0.530 0. 77 B 40 1/13/73 2:00 0. 967 25 2.04 0.510 0.984 24 11/28/73 9:00 0. 961 26 1. 96 0. 4 90 1. 57 7 12/26/74 23:00 0. 961 27 1. 89 0.470 0.897 32 12/02/75 20:00 0. 943 28 1. 82 0.450 0.594 47 8/26/77 2:00 0.940 29 1. 7 5 0.430 1.11 21 9/22/78 19:00 0.908 30 1. 70 0.410 0. 607 46 9/08/79 15:00 0.902 31 1. 64 0.390 1. 26 15 12/14/79 21:00 0.897 32 1.59 0.370 1.11 22 li/21/80 11: 00 0.897 33 1. 54 0.350 2.05 4 10/06/81 15:00 0.894 34 1. 4 9 0.330 0.902 31 1/05/83 8:00 0.892 35 1. 45 0.310 0. 961 27 1/03/84 1:00 0.869 36 1. 41 0.291 0. 563 49 6/06/85 23:00 0.847 37 1.37 0. 271 1. 55 8 1/18/86 16:00 0. 811 38 1. 33 0.251 1. 41 10 11/24/86 3:00 0.788 39 1.30 0.231 0. 619 45 1/14/88 12:00 0.778 40 1.27 0. 211 0.567 48 11/05/88 14:00 0.740 41 1.24 0.191 2. 63 2 1/09/90 6:00 0.697 42 1. 21 0.171 2.28 3 11/24/90 8:00 0.694 43 1.18 0.151 0.897 33 1/27 / 92 15:00 0.632 44 1.15 0.131 0. 632 44 3/22/93 22:00 0. 619 45 1.12 0 .111 0.413 50 11/30/93 22: 00 0.607 46 1.10 0. 091 0.847 37 12/27/94 1:00 0.594 47 1.08 0.071 1. 79 5 2/08/96 10:00 0.567 48 1. 05 0.051 1. 34 12 1/02/97 6:00 0.563 49 1. 03 0.031 1.17 18 10/04/97 15:00 0.413 50 1.01 0. 011 Computed Peaks 2. 90 100.00 0.990 Computed Peaks 2.53 50.00 0.980 Computed Peaks 2.18 25.00 0.960 Computed Peaks 1. 75 10.00 0.900 Computed Peaks 1. 67 8. 00 0.875 Computed Peaks 1.44 5.00 0.800 Computed Peaks 1.01 2. 00 0.500 Computed Peaks 0.759 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-200. tsf Mean= -0.308 StdDev= 0.145 Project Location:Sea-Tac Skew= 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0. 561 18 2/16/49 21:00 1.12 1 89.50 0.989 1. 09 2 3/03/50 16:00 1. 09 2 32.13 0.969 B-54 SE I 4¢1' Street-June 1007 0.660 9 2/09/51 14:00 0.987 3 19.58 0.949 0.398 39 1/30/52 8:00 0.834 4 14.08 0.929 0.358 43 3/24/53 15:00 0.795 5 10.99 0.909 0.475 24 12/19/53 19: 00 0.777 6 9.01 0. 88 9 0.554 19 2/07/55 17:00 0.700 7 7.64 0. 869 0.562 16 12/20/55 17:00 0. 697 8 6.63 0.849 0.607 13 12/09/56 14:00 0.660 9 5.86 0 .829 0.462 25 12/25/57 16:00 0.626 10 5.24 0 .809 0.364 42 1/26/59 20:00 0. 623 11 4.75 0. 789 0.569 15 11/20/59 21:00 0.615 12 4.34 0. 7 69 0.435 30 2/14/61 21:00 0.607 13 3.99 0. 749 0.339 45 11/22/61 2:00 0.574 14 3.70 0. 7 29 0.438 29 12/15/62 2:00 0.569 15 3.44 0. 7 09 0. 477 23 12/31/63 23:00 0.562 16 3.22 0. 6 90 0.395 40 12/21/64 4:00 0. 561 17 3.03 0.670 0.435 31 1/05/66 16:00 0. 561 18 2.85 0. 650 0.623 11 1/19/67 14:00 0.554 19 2.70 0. 630 0.574 14 8/24/68 16:00 0.502 20 2. 56 0.610 0. 421 36 12/03/68 16:00 0. 500 21 2.44 0. 5 90 0.434 32 1/13/70 22:00 0. 4 94 22 2.32 0.570 0. 42 6 35 12/06/70 8:00 0.477 23 2.22 0. 550 0.777 6 2/27/72 7:00 0.475 24 2.13 0. 530 0.388 41 1/13/73 2:00 0. 4 62 25 2.04 0.510 0. 44 6 28 11/28/73 9:00 0.459 26 1. 96 0. 4 90 0.697 8 12/26/74 23:00 0.457 27 1. 89 0. 4 70 0.427 34 12/02/75 20:00 0.446 28 1. 82 0. 4 so 0. 34 6 44 8/26/77 2:00 0.438 29 1. 75 0. 430 0.502 20 9/22/78 19: 00 0.435 30 1. 70 0.410 0.401 38 9/08/79 15:00 0.435 31 1. 64 0. 3 90 0.561 17 12/14/79 21:00 0.434 32 1. 59 0. 370 0.494 22 11/21/80 11: 00 0.432 33 1. 54 0.350 0.834 4 10/06/81 15:00 0.427 34 1. 4 9 0.330 0.457 27 10/28/82 16:00 0.426 35 1. 45 0.310 0.459 26 1/03/84 1:00 0.421 36 1. 41 0. 2 91 0.307 46 6/06/85 22:00 0.407 37 1. 37 0.271 0.700 7 1/18/86 16:00 0.401 38 1. 33 0.251 0. 62 6 10 11/24/86 3:00 0.398 39 1. 30 0. 231 0.296 48 1/14/88 12:00 0.395 40 1. 27 0. 211 0.283 49 8 /21/89 17:00 0.388 41 1. 24 0.191 1.12 1 1/09/90 6:00 0. 364 42 1. 21 0.171 0.987 3 11/24/90 8:00 0.358 43 1.18 0 .151 0.432 33 1/27 /92 15:00 0.346 44 1.15 0.131 0.302 47 3/22/93 22:00 0.339 45 1.12 0.111 0.254 50 11/30/93 22:00 0.307 46 1.10 0.091 0.407 37 2/18/95 20:00 0.302 47 1. 08 0.071 0.795 5 2/08/96 10:00 0.296 48 1.05 0.051 0.615 12 1/02/97 6:00 0.283 49 1.03 0.031 0.500 21 10/04/97 15:00 0.254 so 1.01 0.011 Computed Peaks 1. 21 100.00 0.990 Computed Peaks 1. 06 50.00 0.980 Computed Peaks 0.931 25.00 0. 960 Computed Peaks 0.766 10.00 0.900 Computed Peaks 0.733 8.00 0.875 Computed Peaks 0.645 5.00 0.800 Computed Peaks 0.479 2.00 0. 500 Computed Peaks 0.380 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-210. tsf Mean= 0.056 StdDev~ 0 .136 Project Location:Sea-Tac Skew"" 0.482 s.55 SE 14.f~ S/reet-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.24 19 2/16/49 21:00 2.48 1 89.50 0.989 2.42 2 3/03/50 16:00 2.42 2 32.13 0. 969 1.40 11 2/09/51 2:00 2. 20 3 19. 58 0.949 0.884 40 1/30/52 8: 00 1. 97 4 14.08 0. 929 0.845 44 3/24/53 15:00 1. 72 5 10.99 0. 909 1.10 25 12/19/53 19:00 1. 66 6 9.01 0.889 1.19 21 2/07/55 17:00 1. 56 7 7. 64 0. 869 1. 21 20 12/20/55 17:00 1. 4 9 8 6.63 0. 84 9 1. 38 12 12/09/56 14:00 1. 46 9 5.86 0. 82 9 1.11 24 12/25/57 16:00 1. 4 3 10 5.24 0. 809 0.835 45 1/26/59 20:00 1. 40 11 4.75 0. 789 1.18 22 11/20/59 21:00 1. 38 12 4.34 0. 769 0. 996 33 2/14/61 21:00 1.37 13 3.99 0. 749 0.867 43 11/22/61 2:00 1. 37 14 3.70 0. 729 1. 01 30 12/15/62 2:00 1.33 15 3.44 0. 709 1. 09 26 12/31/63 23:00 1.30 16 3.22 0.690 0.936 39 12/21/64 4:00 1. 30 17 3.03 0.670 0.995 34 1/05/66 16:00 1. 27 18 2.85 0.650 1. 43 10 11/13/66 19: 00 1. 24 19 2.70 0.630 1. 46 9 8/24/68 16:00 1. 21 20 2.56 0.610 0.937 38 12/03/68 16: 00 1.19 2) 2.44 0 .590 1. 00 31 1/13/70 22:00 1.18 22 2.32 0.570 0.989 35 12/06/70 8:00 1.16 23 2.22 0.550 1.72 5 2/27 /72 7:00 1.11 24 2.13 0.530 0.876 41 1/13/73 2:00 1.10 25 2.04 0.510 1. 08 27 11/28/73 9:00 1. 09 26 1. 96 0. 490 1. 56 7 12/26/74 23:00 1. 08 27 1. 89 0. 4 70 0. 94 9 36 12/02/75 20:00 1. 06 28 1. 82 0.450 0.870 42 8/26/77 2: 00 1. 02 29 1. 75 0. 430 1. 30 16 9/22/78 19: 00 1. 01 30 1. 70 0.410 0.999 32 9/08/79 15:00 1.00 31 1. 64 0. 390 1. 33 15 12/14/79 21:00 0.999 32 1. 59 0.370 1. 27 18 11/21/80 11:00 0. 996 33 1. 54 0. 350 1. 97 4 10/06/81 15:00 0.995 34 1.49 0.330 1.16 23 10/28/82 16: 00 0.989 35 l. 45 0.310 1. 06 28 1/03/84 1:00 0.949 36 l. 41 0. 291 0. 775 46 6/06/85 22:00 0.937 37 1. 37 0. 271 1. 49 8 1/18/86 16:00 0.937 38 1. 33 0. 251 1. 37 13 10/26/86 0:00 0.936 39 l. 30 0. 231 0.656 48 1/14/88 12:00 0.884 40 1. 27 0 .211 0. 712 47 11/05/88 14:00 0.876 41 1. 24 0 .191 2.48 1 1/09/90 6:00 0.870 42 1. 21 0.171 2.20 3 11/24/90 8:00 0.867 43 1.18 0.151 l. 02 29 1/27/92 15:00 0. 845 44 1.15 0 .131 0.643 49 3/22/93 22:00 0.835 45 1.12 0.111 0.636 50 11/30/93 22:00 0.775 46 1.10 0.091 0. 937 37 11/30/94 4:00 0. 712 47 1. 08 0.071 1. 66 6 2/08/96 10:00 0. 656 48 1. 05 0.051 1. 37 14 1/02/97 6:00 0.643 49 1. 03 0. 031 1.30 17 10/04/97 15:00 0.636 50 1. 01 0. Oll Computed Peaks 2. 63 100.00 0.990 Computed Peaks 2.34 50.00 0.980 Computed Peaks 2.07 25.00 0. 960 Computed Peaks 1. 72 10.00 0.900 Computed Peaks 1. 66 8.00 0.875 Computed Peaks 1. 47 5.00 0.800 B-56 SE 144'h Streer-June2007 Computed Peaks 1.11 2.00 0.500 Computed Peaks 0.893 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-220.tsf Mean= -0.235 StdDev-0 .114 Project Location:Sea-Tac Skew-0. 400 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.601 21 2/16/49 21:00 1. 09 1 89. 50 0.989 1. 04 2 3/03/50 16:00 1. 04 2 32.13 0. 969 0.624 19 2/09/51 2:00 0. 989 3 19.58 0.949 0.466 40 10/15/51 13:00 0.955 4 14.08 0.929 0.453 44 3/24/53 15:00 0.823 5 10.99 0.909 0.557 26 12/19/53 19:00 0. 811 6 9.01 0.889 0.571 23 11/25/54 2:00 0.772 7 7.64 0.869 0.558 25 11/18/55 15:00 0.765 8 6.63 0.849 0.672 14 12/09/56 14:00 0. 723 9 5.86 0.829 0.584 22 12/25/57 16: 00 0.713 10 5.24 0.809 0.432 47 11/18/58 13:00 0.702 11 4.75 0.789 0.567 24 11/20/59 5:00 0.688 12 4.34 0. 7 69 0.501 36 2/14/61 21:00 0.683 13 3.99 0.749 0.488 38 11/22/61 2:00 0. 672 14 3.70 0.729 0.501 35 12/15/62 2:00 0.666 15 3.44 0.709 0.556 27 12/31/63 23:00 0.660 16 3.22 0. 6 90 0.497 37 12/21/64 4:00 0.658 17 3.03 0.670 0.503 34 1/05/66 16:00 0.641 18 2.85 0.650 0.765 8 11/13/66 19: 00 0.624 19 2.70 0.630 0. 823 5 8/24/68 16:00 0.622 20 2.56 0. 610 0.460 41 12/03/68 16:00 0.601 21 2.44 0.590 0.508 33 1/13/70 22:00 0.584 22 2.32 0.570 0.487 39 12/06/70 8:00 0.571 23 2.22 0.550 0.772 7 2/27 /72 7:00 0.567 24 2.13 0.530 0.445 46 1/13/73 2:00 0.558 25 2.04 0.510 0.545 28 11/28/73 9:00 0.557 26 1. 96 0.490 0.723 9 12/26/74 23:00 0.556 27 1. 89 0.470 0.460 42 12/02/75 20:00 0.545 28 1. 82 0.450 0. 520 31 8/26/77 2:00 0.540 29 1. 75 0.430 0. 713 10 9/17/78 2:00 0.524 30 1. 70 0.410 0. 622 20 9/08/79 15:00 0.520 31 1. 64 0.390 0.658 17 12/14/79 21:00 0.518 32 1. 59 0.370 0.683 13 11/21/80 11: 00 0.508 33 1.54 0.350 0.955 4 10/06/81 0:00 0.503 34 1. 4 9 0.330 0.666 15 10/28/82 16:00 0.501 35 1. 45 0. 310 0. 540 29 1/03/84 1:00 0.501 36 1. 41 0.291 0. 453 45 6/06/85 22:00 0.497 37 1. 37 0. 271 0. 660 16 1/18/86 16:00 0.488 38 1. 33 0.251 0.811 6 10/26/86 0:00 0.487 39 1. 30 0.231 0.351 49 11/11/87 0:00 0.466 40 1. 27 0. 211 0. 455 43 8/21/89 17:00 0. 4 60 41 1. 24 0.191 1. 09 1 1/09/90 6:00 0.460 42 1.21 0.171 0. 989 3 11/24/90 8:00 0.455 43 1.18 0.151 0. 524 30 1/27/92 15:00 0.453 44 1.15 0.131 0.330 so 11/01/92 16:00 0.453 45 1.12 0 .111 0.386 48 11/30/93 22:00 0.445 46 1.10 0. 091 0.518 32 11/30/94 4:00 0.432 47 1. 08 0. 071 0. 702 11 2/08/96 10:00 0.386 48 1. 05 0.051 0. 641 18 1/02/97 6:00 0.351 49 1. 03 0.031 0. 688 12 10/04/97 15:00 0.330 50 1. 01 0. 011 s.57 SE 14¢l' Street-June 2007 Computed Peaks 1.16 100.00 0.990 Computed Peaks 1. 05 50.00 0.980 Computed Peaks 0.953 25.00 0. 960 Computed Peaks 0.822 10.00 0.900 Computed Peaks 0. 795 8.00 0.875 Computed Peaks 0. 721 5.00 0.800 Computed Peaks 0.572 2.00 0.500 Computed Peaks 0.474 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-220rd.tsf Mean= -0. 991 StdDev-0.418 Project Location:Sea-Tac Skew-0.698 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0. 039 38 2/22/49 22: 00 0.935 5.13 1 89.50 0.989 0 .110 19 3/05/50 6:00 0.681 5.10 2 32.13 0. 969 0.489 6 2/09/51 15:00 0.575 5.08 3 19.58 0.949 0.035 43 2/04/52 8:00 0.569 5.08 4 14.08 0. 929 0.099 22 1/18/53 21:00 0.523 5.07 5 10.99 0.909 0.064 35 1/07/54 20:00 0.489 5.06 6 9. 01 0.889 0.040 36 2/08/55 22:00 0.483 5.06 7 7. 64 0.869 0.159 12 1/06/56 10:00 0.478 5.06 8 6.63 0.849 0.067 34 2/26/57 4:00 0.389 5.04 9 5.86 0.829 0.100 21 1/17/58 7:00 0 .277 5.02 10 5.24 0.809 0.040 37 1/27/59 1:00 0.160 4.87 11 4.75 0.789 0.478 B 11/20/59 21: 00 0.159 4.86 12 4.34 0.769 0 .134 16 11/24/60 10:00 . 0 .152 4.82 13 3.99 0.749 0.035 46 12/24/61 6:00 0.141 4.77 14 3.70 0. 729 0.087 27 11/26/62 10:00 0.138 4.75 15 3.44 0.709 0.100 20 11/19/63 16:00 0 .134 4.73 16 3.22 0. 690 0.138 15 11/30/64 14:00 0.120 4.63 17 3.03 0.670 0.077 33 1/06/66 21:00 0 .114 4.58 18 2.85 0.650 0 .114 18 12/13/66 11: 00 0 .110 4.54 19 2.70 0.630 0.082 29 1/20/68 19:00 0.100 4.41 20 2.56 0.610 0.080 30 12/11/68 6:00 0.100 4.41 21 2.44 0. 590 0.093 23 1/27 /70 2:00 0.099 4.38 22 2. 32 0.570 0.087 28 12/07 /70 5:00 0.093 4.30 23 2.22 0.550 0.483 7 3/06/72 19:00 0.093 4.29 24 2.13 0.530 0.152 13 12/26/72 5:00 0. 092 4.28 25 2.04 0.510 0.090 26 1/16/74 18:00 0.090 4.26 26 1. 96 0. 4 90 0.039 39 1/14/75 2: OD 0.087 4.22 27 1. 89 0.470 0.078 32 12/04/75 2:00 0.087 4.21 28 1. 82 0. 450 0.031 49 8/26/77 8:00 0.082 4.15 29 1. 75 0.430 0.120 17 12/15/77 17:00 0.080 4 .13 30 1. 70 0.410 0.032 48 2/13/79 1: 00 0.080 4.13 31 1. 64 0.390 0. 277 10 12/17 /79 17:00 0.078 4 .11 32 1. 59 0. 370 0. 092 25 12/30/80 16: 00 0.077 4.10 33 1.54 0.350 0.681 2 10/06/81 16:00 0.067 4.02 34 1. 49 0.330 0. 080 31 1/06/83 14:00 0.064 4.01 35 1. 45 0.310 0. 035 45 12/10/83 21:00 0.040 3.85 36 1. 41 0. 2 91 0.037 41 11/04/84 8:00 0.040 3.78 37 1. 37 0.271 0.141 14 1/18/86 23:00 0. 039 3.71 38 1. 33 0.251 0.569 4 11/24/86 4:00 0.039 3.67 39 1. 30 0 .231 0.038 40 12/10/87 8:00 0.038 3.49 40 1.27 0.211 0.035 44 11/05/88 23:00 0.037 3.16 41 1. 24 0 .191 0.935 1 1/09/90 8:00 0. 037 3.13 42 1. 21 0 .171 0.523 5 11/24/90 11: OD 0.035 3.01 43 1.18 0.151 0. 093 24 1/31/92 6:00 0.035 3.00 44 1.15 0.131 B-58 SE 144'~ Street-June 2007 0.034 47 1/26/93 5:00 0.035 2. 92 45 1. 12 O .111 0.030 50 2/17/94 23:00 0.035 2. 90 46 1. 10 0. 091 0.160 11 12/27/94 6:00 0.034 2.75 47 1. 08 0.071 0.575 3 2/08/96 11: 00 0.032 2.43 48 1. 05 0.051 0.389 9 1/02/97 10:00 0.031 2.31 49 1. 03 0.031 0.037 42 1/25/98 0:00 0. 030 2.22 50 1. 01 0. 011 Computed Peaks 1. 55 5.20 100.00 0. 990 Computed Peaks 1. 04 5.15 50.00 0.980 Computed Peaks 0.678 5.10 25.00 0.960 Computed Peaks 0.368 5.04 10.00 0.900 Computed Peaks 0.323 5.03 8.00 0.875 Computed Peaks 0.219 5. 01 5.00 0.800 Computed Peaks 0. 091 4.27 2.00 0.500 Computed Peaks 0.048 3. 96 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-230.tsf Mean:: 0.197 StdDev~ 0.103 Project Location:Sea-Tac Skew= 0.461 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.60 21 2/16/49 21:00 2. 72 1 89.50 0.989 2.49 4 3/03/50 16:00 2. 57 2 32.13 0.969 1. 64 20 2/09/51 2:00 2. 53 3 19.58 0.949 1. 32 40 10/15/51 13:00 2.49 4 14.08 0.929 1.23 46 3/24/53 15:00 2.24 5 10.99 0.909 1. 4 9 27 12/19/53 19:00 2.22 6 9.01 0.889 1. 57 22 11/25/54 2:00 2.05 7 7.64 0.869 1.52 25 11 / 18 / 55 15:00 2.00 8 6.63 0.849 1. 77 16 12/09/56 14:00 1. 96 9 5.86 0.829 1. 57 23 12/25/57 16:00 1. 88 10 5 .24 0.809 1. 21 47 11/18/58 13:00 1. 86 11 4. 75 0.789 1. 54 24 11/20/59 5:00 1. 84 12 4. 34 0. 769 1. 33 38 2/14/61 21: 00 1. 83 13 3.99 0. 749 1. 33 37 11/22/61 2:00 1. 81 14 3. 70 0. 729 1. 33 39 12/15/62 2:00 1.80 15 3.44 0. 709 1. 52 26 12/31/63 23:00 1. 77 16 3.22 0.690 1. 36 36 12/21/64 4:00 1. 7 5 17 3.03 0.670 1. 37 34 1/05/66 16:00 1. 73 18 2.85 0.650 2.05 7 11/13/66 19:00 1. 68 19 2.70 0.630 2.22 6 8/24/68 16: 00 1. 64 20 2.56 0.610 1. 26 42 12/03/68 16:00 1. 60 21 2.44 0 .590 1. 38 33 1/13/70 22:00 1. 57 22 2.32 0.570 1. 31 41 12/06/70 8:00 1. 57 23 2.22 0.550 1. 96 9 2/27 /72 7:00 1. 54 24 2.13 0.530 1. 24 45 1/13/73 2:00 1.52 25 2.04 0.510 1. 40 32 11/28/73 9:00 1.52 26 1. 96 0.490 1. 88 10 12/26/74 23:00 1. 4 9 27 1. 8 9 0. 470 1. 25 44 12/02/75 20:00 1. 47 28 1. 82 0. 450 1. 47 28 8/26/77 2:00 1.44 29 1. 75 0.430 2.00 8 9/17/78 2:00 1. 42 30 1. 70 0.410 1. 80 15 9/08/79 15:00 1. 41 31 1. 64 0. 390 1. 73 18 12/14/79 21 :00 1. 40 32 1.59 0.370 1. 86 11 11/21/80 11:00 1. 38 33 1.54 0.350 2.57 2 10/06/81 0:00 1. 37 34 1. 4 9 0.330 1. 84 12 10/28/82 16:00 1. 36 35 1. 45 0.310 1. 44 29 1/03/84 1:00 1. 36 36 1. 41 0 .291 1. 26 43 6/06/85 22:00 1. 33 37 1. 37 0.271 1. 75 17 1/18/86 16:00 1.33 38 1. 33 0 .251 8-59 SE 14.fh Street-June 2007 2.24 5 10/26/86 0:00 1. 33 39 1. 30 0 .231 1.05 49 11/11/87 0: 00 1. 32 40 1. 27 0.211 1. 36 35 8/21/89 17:00 1. 31 41 1. 24 0 .191 2. 72 1 1/09/90 6:00 1. 26 42 1.21 0.171 2.53 3 11/24/90 8:00 1. 26 43 1.18 0.151 1. 41 31 1/27 /92 15:00 J. 25 44 1.15 0.131 0.962 50 11/01/92 16:00 1. 24 45 1.12 0.111 1.10 48 11/30/93 22:00 1.23 46 1.10 0.091 1.42 30 ).1/30/94 4:00 1.21 47 1. 08 0 .071 1. 83 13 2/08/96 10:00 1.10 48 1. 05 0 .051 1. 68 19 1/02/97 6:00 1. 05 49 1. 03 0.031 1. 81 14 10/04/97 15:00 0. 962 50 1. 01 0 .011 Computed Peaks 2.95 100.00 0. 990 Computed Peaks 2. 70 50.00 0.980 Computed Peaks 2.46 25.00 0.960 Computed Peaks 2.15 10.00 0.900 Computed Peaks 2.09 8.00 0.875 Computed Peaks 1. 91 5.00 0. 800 Computed Peaks 1. 55 2.00 0.500 Computed Peaks 1. 31 1. 30 0. 2 31 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-230rd.tsf Mean= -0.774 StdDev= 0.235 Project Location:Sea-Tac Skew= 1. 289 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.118 39 2/22/49 6:00 0.559 7.00 1 89.50 0.989 0.141 17 3/05/50 11:00 0.550 6.95 2 32.13 0. 969 0.559 1 2/09/51 20: 00 0.484 6.59 3 19.58 0. 94 9 0.108 46 2/04/52 6:00 0.480 6.57 4 14.08 0. 92 9 0.130 29 1/23/53 8:00 0.479 6.56 5 10.99 0.909 0.130 30 1/06/54 12:00 0.478 6. 'i6 6 9.01 0.889 0.129 32 2/08/55 8:00 0. 471 6.53 7 7.64 0.869 0.247 11 1/06/56 12:00 0. 452 6.45 8 6.63 0.849 0 .12 9 33 2/26/57 4:00 0.407 6.27 9 5.86 0.829 0.136 20 1/17/58 8:00 0. 291 6.03 10 5.24 0.809 0.119 38 1/24/59 16:00 0.247 5.94 11 4.75 0.789 0.478 6 11/21/59 3:00 0. 219 5.76 12 4.34 0.769 0.142 15 11/24/60 17:00 0.218 5.75 13 3.99 0.749 0.104 48 12/24/61 6:00 0.176 5.62 14 3.70 0.729 0.132 26 11/27/62 5:00 0.142 5.42 15 3.44 0.709 0.136 21 11/19/63 18:00 0.142 5.40 16 3.22 0.690 0.218 13 12/01/64 8:00 0.141 5.33 17 3.03 0. 670 0 .125 37 1/07/66 3:00 0.140 5.27 18 2.85 0.650 0.136 22 12/15/66 8:00 0.138 5 .16 19 2.70 0.630 0.127 34 1/20/68 21:00 0.136 5.01 20 2.56 0.610 0.125 35 12/11/68 7:00 0 .136 4 .96 21 2.44 0.590 0 .132 27 1/27 /70 4:00 0 .136 4 .96 22 2.32 0. 570 0.134 25 12/07 /70 11:00 0.135 4.90 23 2.22 0.550 0.480 4 3/06/72 22:00 0.135 4.89 24 2.13 0.530 0.219 12 12/27 /72 18:00 0.134 4.83 25 2.04 0.510 0.135 23 1/16/74 19:00 0.132 4.68 26 1. 96 0.490 0 .125 36 12/27 /74 10:00 0.132 4.68 27 1. 89 0.470 0.131 28 12/04/75 3:00 0.131 4. 62 28 1. 82 0.450 0 .105 47 8/26/77 7:00 0.130 4. 54 29 1. 75 0.430 0.138 19 12/15/77 21:00 0.130 4.54 30 1. 70 0.410 0.102 49 2/12/79 17:00 0.130 4. 54 31 1. 64 0.390 0.471 7 12/17 /79 20:00 0.129 4.48 32 1. 59 0.370 B·60 SE 14,t!t Streel-June 2007 0 .130 31 12/30/80 22:00 0.129 4. 4 6 33 1. 54 0.350 0.291 J 0 10/06/81 19:00 0.127 4.31 34 l. 4 9 0.330 0 .135 24 1/08/83 3:00 0.125 4.18 35 1. 45 0.310 0 .111 44 12/10/83 19:00 0.125 4.18 36 1. 41 0. 2 91 0 .117 40 11/04/84 0:00 0.125 4.17 37 1. 37 o .271 0 .176 14 1/19/86 7:00 0.119 3. 78 38 1. 33 0.251 0.407 9 11/24/86 8: 00 0 .118 3.72 39 1. 30 0.231 0 .114 41 12/09/87 22:00 0.117 3.68 40 1. 27 0.211 0 .113 43 11/05/88 22:00 0 .114 3.53 41 1. 24 0 .191 0.484 3 1/09/90 14:00 0 .113 3. 46 42 1. 21 0.171 0.452 8 4/05/ 91 6:00 0 .113 3. 40 43 1.18 0 .151 0.140 18 1/31/92 22:00 0 .111 3. 33 44 1.15 0 .131 0.109 45 3/23/ 93 12:00 0.109 3.22 45 1.12 0 .111 0.098 50 2/17/94 21:00 0.108 3 .15 46 1.10 0. 0 91 0.142 16 12/27/94 20:00 0.105 2.98 47 1.08 0.071 0.550 2 2/09/96 4:00 0.104 2.94 48 1. 05 0.051 0.479 5 1/02/97 12:00 0.102 2. 76 49 1. 03 0.031 0 .113 42 10/30/97 11 :00 0.098 2.59 50 1. 01 0. 011 Computed Peaks 0.953 7.57 100.00 0.990 Computed Peaks 0. 711 7.51 50.00 0.980 Computed Peaks 0.526 6.81 25.00 0. 960 Computed Peaks 0.347 6. 09 10.00 0.900 Computed Peaks 0.320 6.07 8.00 0.875 Computed Peaks 0.249 5.94 5.00 0.800 Computed Peaks 0.150 5.55 2.00 0.500 Computed Peaks o .111 3.30 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-232.tsf Mean= -1.477 StdDev-0.232 Project Location:Sea-Tac Skew--0.124 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.041 16 2/16/49 22:00 O. 093 1 89.50 0.989 0.080 5 3/03/50 16:00 0.088 2 32.13 0.969 0.088 2 2/09/51 18:00 0.083 3 19.58 0.949 0.028 32 1/30/52 9:00 0.082 4 14.08 0. 929 0.021 42 1/18/53 19:00 0.080 5 10.99 0.909 0.031 27 1/06/54 5:00 0.068 6 9.01 0.889 0.054 10 2/07/55 21:00 0.065 7 7.64 0.869 0.046 13 12/20/55 17:00 0.059 8 6.63 0.849 0.036 21 12/09/56 15:00 0.055 9 5.86 0.829 0.038 20 1/16/58 20:00 0.054 10 5.24 0.809 0. 032 24 1/24/59 2:00 0.054 11 4.75 0.789 0.059 8 11/20/59 21:00 0.047 12 4.34 0.769 0.032 22 2/24/61 15:00 0.046 13 3.99 0.749 0.019 44 1/03/62 1:00 0.045 14 3.70 0. 729 0.026 36 11/25/62 14 :00 0.042 15 3.44 0.709 0. 032 25 1/01/64 18:00 0.041 16 3.22 o. 690 0.022 39 11/30/64 12:00 0.040 17 3.03 0.670 0.024 38 1/06/66 3:00 0.040 18 2.85 0.650 0.054 11 1/19/67 14:00 0.039 19 2.70 0.630 0.032 23 2/03/68 23:00 0.038 20 2.56 0.610 0.031 28 12/03/68 17: 00 0.036 21 2.44 0.590 0.026 34 1/13/70 23: 00 0.032 22 2.32 0.570 0.021 41 12/06/70 8:00 0.032 23 2.22 0.550 0.065 7 2/28/72 3:00 0.032 24 2 .13 0.530 0.029 30 1/13/73 5:00 0.032 25 2.04 0.510 0. 031 26 1/15/74 2: 00 0.031 26 1. 96 0. 4 90 B-61 SE 14.f' Stl'eet-June 2007 0.047 12 12/26/74 23:00 0.031 27 1. 89 0.470 0. 02 9 29 12/03/75 17:00 0.031 28 1. 82 0. 450 0.004 50 3/24/77 20:00 0.029 29 1. 75 0.430 0.025 37 12/10/77 17:00 0.029 30 1. 70 0.410 0.015 46 2/12/79 8:00 0.028 31 1. 64 0.390 0.040 17 12/15/79 8:00 0.028 32 1. 59 0.370 0.022 40 12/26/80 4: 00 0.027 33 1. 54 0.350 0.040 18 10/06/81 15:00 0.026 34 1. 49 0.330 0.039 19 1/05/83 8:00 0.026 35 1. 45 0.310 0.026 35 1/24/84 11: 00 0.026 36 1. 41 0.291 0.012 48 2/11/85 5:00 0.025 37 1. 37 0.271 0.068 6 1/18/86 21:00 0.024 38 1. 33 0.251 0.055 9 11/24/86 4:00 0.022 39 1. 30 0.231 0 .021 43 1/14/88 13: 00 0.022 40 1.27 0. 211 0.013 47 4/05/89 16:00 0.021 41 1. 24 0.191 0.093 1 1/09/90 9:00 0.021 42 1. 21 0.171 0.082 4 4/05/91 2:00 0. 021 43 1.18 0.151 0.027 33 1/27/92 17:00 0. 019 44 1.15 0 .131 0.028 31 3/23/93 0:00 0. 016 45 1.12 0 .111 0.008 49 3/03/94 4:00 0. 015 46 1.10 0.091 0.042 15 2/19/95 20:00 0.013 47 1. 08 0. 071 0.083 3 2/09/96 1:00 0. 012 48 1. 05 0.051 0.045 14 1/02/97 9:00 0. 008 49 1. 03 0. 031 0. 016 45 1/07/98 9:00 0.004 50 1.01 0. 011 Computed Peaks 0 .110 100.00 0.990 Computed Peaks 0.097 50.00 0.980 Computed Peaks 0.083 25. 00 0. 960 Computed Peaks 0. 066 10.00 0. 900 Computed Peaks 0. 062 8.00 0. 875 Computed Peaks 0.053 5.00 0.800 Computed Peaks 0.034 2.00 0.500 Computed Peaks 0.022 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-240.tsf Mean= 0 .137 StdDev-0 .114 Project Location:Sea-Tac Skew= 0.402 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 42 21 2/16/49 21:00 2.57 1 89.50 0. 989 2.44 2 3/03/50 16:00 2.44 2 32.13 0. 969 1. 47 19 2/09/51 2:00 2.33 3 19. 58 0. 949 1. io 40 10/15/51 13:00 2.25 4 14. 08 0.929 1. 07 44 3/24/53 15:00 1. 94 5 10.99 0.909 1. 31 25 12/19/53 19: 00 1. 91 6 9.01 0. 889 1. 34 23 11/25/54 2:00 1. 82 7 7. 64 0.869 1. 31 26 11/18/55 15:00 1. 80 8 6.63 0.849 1.58 14 12/09/56 14:00 1. 70 9 5.86 0. 829 1. 38 22 12/25/57 16:00 1. 68 10 5.24 0.809 1. 02 47 11/18/58 13:00 1. 65 11 4.75 0.789 1.33 24 11/20/59 5:00 1. 62 12 4.34 a. 769 1.18 35 2/14/61 21:00 1. 61 13 3.99 0.749 1.15 38 11/22/61 2:00 1. 58 14 3.70 0. 729 1.18 36 12/15/62 2:00 1. 57 15 3.44 0. 709 1. 31 27 12/31/63 23:00 1. 55 16 3.22 0. 690 1.17 37 12/21/64 4:00 1. 55 17 3.03 0. 670 1.18 34 1/05/66 16:00 1. 51 18 2.85 0. 650 1. 80 8 11/13/66 19:00 1. 4 7 19 2.70 0. 630 1. 94 5 8/24/68 16:00 1. 4 6 20 2.56 0.610 B-62 SE 14.f' Street-Jww 2007 1. 08 41 12/03/68 16: 00 1. 42 21 2. 4 4 0 .590 1.20 33 1/13/70 22:00 1. 38 22 2.32 0.570 1.15 39 12/06/70 8:00 1. 34 23 2.22 0.550 1.82 7 2/27 /72 7:00 1. 33 24 2 .13 0.530 1.05 46 1/13/73 2:00 1. 31 25 2.04 0.510 1.28 28 11/28/73 9:00 1. 31 26 1. 96 0. 490 1. 70 9 12/26/74 23:00 1. 31 27 1. 8 9 0.470 1. 08 42 12/02/75 20:00 1. 28 28 1. 82 0.450 1.23 31 8/26/77 2: 00 1. 27 29 1. 75 0.430 1.68 10 9/17/78 2:00 1. 23 30 1. 70 0.410 1.46 20 9 / 08 /7 9 15:00 1. 23 31 1. 64 0.390 1.55 17 12/14/79 21: 00 1. 22 32 1. 59 0.370 1. 61 13 11/21/80 11: 00 1. 20 33 1.54 0.350 2. 2 5 4 10/06/81 0:00 1.18 34 1. 49 0.330 1.57 15 10/28/82 16:00 1.18 35 1.45 0.310 1.27 29 1/03/84 1:00 1.18 36 1.41 0 .291 1. 07 45 6/06/85 22:00 1.1 7 37 1.37 0.271 1. 55 16 1/18/86 16: 00 1.15 38 1.33 0.251 1. 91 6 10/26/86 0:00 1.15 39 1. 30 0.231 0. 82 8 49 11/11/87 0:00 1.10 40 1. 27 0.211 1. 07 43 8/21/89 17: 00 1. 08 41 1.24 0.191 2.57 1 1/09/90 6:00 1. 08 42 1.21 0 .171 2.33 3 11/24/90 8:00 1. 07 43 1.18 0 .151 1.23 30 1/27/92 15:00 1. 07 44 1.15 0.131 0.778 50 11/01/92 16:00 1. 07 45 1.12 0 .111 0.911 48 11/30/93 22 :00 1. 05 46 1.10 0.091 1. 22 32 11/30/94 4:00 1. 02 47 1. 08 0.071 1. 65 11 2/08/96 10:00 0. 911 48 1. 05 0.051 1. 51 18 1/02/97 6:00 0.828 49 1. 03 0.031 1. 62 12 10/04/97 15:00 0.778 50 1. 01 0. 011 Computed Peaks 2. 72 100.00 0.990 Computed Peaks 2.48 50.00 0.980 Computed Peaks 2.24 25.00 0. 960 Computed Peaks 1. 94 10.00 0.900 Computed Peaks 1. 87 8.00 0. 875 Computed Peaks 1. 70 5.00 0.800 Computed Peaks 1. 35 2.00 0.500 Computed Peaks 1.12 1. 30 0.231 Flow Frequency Analysis Log Pearson III Coefficients Time Series File:c-240rd.tsf Mean= -0. 255 StdDev-0.169 Project Location:Sea-Tac Skew-1.275 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.471 30 2/17/49 1:00 1.34 4.97 1 89.50 0.989 0.524 18 3/04/50 4:00 1. 26 4.89 2 32.13 0. 969 1. 34 1 2/09/51 19:00 1.26 4.89 3 19. 58 0. 94 9 0.416 44 1/30/52 11: 00 1. 21 4.79 4 14.08 0. 929 0.432 40 9/30/53 17:00 1.21 4.79 5 10. 99 0. 909 0.484 25 1/06/54 7:00 1.16 4. 63 6 9.01 0.889 0.570 11 2/08/55 0:00 1.15 4. 61 7 7. 64 0.869 0.533 16 12/22/55 15:00 1. 08 4.43 8 6.63 0.849 0. 512 19 12/09/56 18:00 0.998 4.20 9 5.86 0.829 0.487 24 1/16/58 23:00 0.943 4.08 10 5.24 0.809 0.459 32 10/19/58 9:00 0. 570 3.66 11 4.75 0.789 1.15 7 11/20/59 23:00 0.565 3.61 12 4.34 0.769 0. 4 90 23 11/20/60 16:00 0.553 3.46 13 3.99 0.749 0.382 47 1/03/62 3:00 0.543 3.34 14 3.70 0. 729 B-63 SE 144'1' Street-June 2007 0.483 27 11/25/62 16:00 0.535 3.24 15 3.44 0.709 0.473 28 1/01/64 20:00 0.533 3.22 16 3.22 0.690 0.499 21 11/24/64 10: 00 0.528 3 .16 17 3.03 0.670 0.421 43 12/28/65 17:00 0.524 3.11 18 2.85 0.650 0.543 14 1/19/67 19:00 0.512 2.96 19 2.70 0.630 0.442 38 2/19/68 4:00 0.508 2. 92 20 2.56 0.610 0.471 29 12/03/68 22:00 0.499 2.82 21 2.44 0. 590 0.469 31 1/14/70 14:00 0. 4 97 2.80 22 2.32 0.570 0.508 20 12/06/70 14:00 0. 4 90 2.73 23 2.22 0.550 0.998 9 2/28/72 7:00 0.487 2.69 24 2.13 0.530 0.440 39 12/26/72 6:00 0.484 2. 65 25 2.04 0.510 0.448 36 1/15/74 8: 00 0.483 2. 65 26 1.96 0. 4 90 0.553 13 12/27 /74 6: 00 0.483 2. 64 27 1.89 0.470 0.497 22 12/04/75 1:00 0.473 2.53 28 1. 82 0. 4 50 0.359 49 8/24/77 0:00 0. 471 2.51 29 1. 75 0. 4 30 0.483 26 9/23/78 11: 00 0.471 2.51 30 1. 70 0.410 0.387 46 11/19/78 8:00 0.469 2. 4 8 31 1. 64 0.390 0.943 10 12/15/79 9:00 0.459 2.38 32 1. 59 0.370 0.426 42 11/21/80 14: 00 0. 457 2.36 33 1.54 0.350 1.26 3 10/06/81 17: 00 0.455 2.34 34 1.49 0.330 0.528 17 1/05/83 15:00 0.450 2.30 35 1. 45 0.310 0.409 45 1/24/84 13:00 0.448 2.28 36 1. 41 0. 2 91 0.455 34 6/07/85 7:00 0.444 2.24 37 1. 37 0.271 1. 08 8 1/18/86 22:00 0.442 2.21 38 1. 33 0.251 1.16 6 11/24/86 7:00 0.440 2.20 39 1. 30 0. 231 0. 427 41 1/14/88 19:00 0.432 2.11 40 1. 27 0. 211 0.368 48 11/05/88 19:00 0.427 2.06 41 1. 24 0 .191 1.26 2 1/09/90 11: 00 0.426 2.05 42 1.21 0.171 1. 21 4 4/05/91 3:00 0. 421 2.01 43 1.18 0.151 0.444 37 1/28/92 10:00 0.416 1. 96 44 1.15 0 .131 0.450 35 3/23/93 5:00 0.409 1.89 45 1.12 0 .111 0.333 50 12/01/93 16:00 0.387 1. 70 46 1.10 0.091 0.535 15 2/19/95 22:00 0.382 1. 66 47 1. 08 0.071 1.21 5 2/09/96 3:00 0.368 1.53 48 1. 05 0.051 0.565 12 1/02/97 12: 00 0.359 1. 4 6 49 1. 03 0. 031 0.457 33 10/30/97 9:00 0.333 1.26 50 1. 01 0.011 Computed Peaks 1. 93 5.23 100.00 0.990 Computed Peaks 1. 56 5.10 50.00 0.980 Computed Peaks 1.26 4. 8 9 25.00 0. 960 Computed Peaks 0.935 4.07 10.00 0.900 Computed Peaks 0.881 3.99 8.00 0.875 Computed Peaks 0.736 3. 89 5.00 0.800 Computed Peaks 0.512 2. 97 2.00 0.500 Computed Peaks 0. 411 1. 91 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-241.tsf Mean= 0.052 StdDev-0 .114 Project Location:Sea-Tac Skew= 0.403 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.17 21 2/16/49 21:00 2.12 1 8 9. 50 0.989 2.02 2 3/03/50 16: 00 2.02 2 32 .13 0.969 1.21 19 2/09/51 2:00 1. 93 3 19.58 0. 94 9 0.902 40 10/15/51 13:00 1.85 4 14 .08 0. 929 0. 87 9 44 3/24/53 15:00 1. 59 5 10.99 0.909 1.08 25 12/19/53 19:00 1.57 6 9.01 0.889 1.11 23 11/25/54 2:00 1. 50 7 7.64 0.869 1. 08 26 11/18/55 15:00 1. 4 8 8 6.63 0.849 B-64 SE 144"' Street-June 2007 1.30 14 12/09/56 14:00 1. 40 9 5.86 0.829 1.13 22 12/25/57 16: 00 1. 38 10 5.24 0.809 0.838 47 11/18/58 13:00 1. 37 11 4.75 0.789 1.10 24 11/20/59 5:00 1.33 12 4.34 0.769 0.972 36 2/14/61 21:00 1. 32 13 3. 99 0.749 0.943 39 11/22/61 2:00 1.30 14 3.70 0. 729 0. 97 3 35 12/15/62 2:00 1. 2 9 15 3.44 0. 709 1. 08 27 12/31/63 23:00 1. 29 16 3.22 0. 690 0. 964 37 12/21/64 4:00 1.27 17 3.03 0.670 0.976 34 1/05/66 16: 00 1. 24 18 2.85 0.650 1.4 8 8 11/13/66 19:00 1.21 19 2.70 0.630 1. 59 5 8/24/68 16: 00 1. 20 20 2.56 0.610 0 .893 42 12/03/68 16:00 1.17 21 2.44 0. 5 90 0.985 33 1/13/70 22:00 1.13 22 2.32 0.570 0. 945 38 12/06/70 8:00 1.11 23 2.22 0.550 1. 50 7 2/27 /72 7:00 1.10 24 2.13 0.530 0.864 46 1/13/73 2:00 1. 08 25 2.04 0.510 1. 06 28 11/28/73 9:00 1. 08 26 1. 96 0. 4 90 1.40 9 12/26/74 23:00 1. 08 27 1. 89 0.470 0.894 41 12/02/75 20:00 1. 06 28 1. 82 0 .450 1. 01 31 8/26/77 2:00 1. 05 29 1. 75 0.430 1. 38 10 9/17 /78 2:00 1. 02 30 1.70 0.410 1.20 20 9/08/79 15:00 1. 01 31 1. 64 0.390 1.27 17 12/14/79 21:00 1. 00 32 1. 59 0.370 1. 32 13 11/21/80 11 :DO 0.985 33 1. 54 0.350 1. 85 4 10/06/81 0:00 0. 976 34 1. 4 9 0.330 1. 2 9 15 10/28/82 16:00 0. 973 35 1.45 0.310 1. 05 29 1/03/84 1:00 0.972 36 1. 41 0. 291 0.877 45 6/06/85 22:00 0.964 37 1. 37 0.271 1. 29 16 1/18/86 16:00 0. 945 38 1. 33 0.251 1. 57 6 10/26/86 0:00 0. 943 39 1. 30 0.231 0.680 49 11/11/87 0:00 0. 902 40 1. 27 0 .211 0.881 43 8/21/89 17: 00 0.894 41 1. 24 0.191 2.12 l 1/09/90 6:00 0.893 42 1. 21 0 .171 1. 93 3 11/24/90 8:00 0.881 43 1.18 0 .151 1. 02 30 1/27 /92 15:00 0. 87 9 44 1.15 0.131 0.639 50 11/01/92 16:00 0.877 45 1.12 0 .111 0.748 48 11/30/93 22:00 0.864 46 1.10 0.091 1. 00 32 11/30/94 4:00 0.838 47 1. 08 0.071 1. 37 11 2/08/96 10:00 0.748 48 1. 05 0.051 1.24 18 1/02/97 6:00 0.680 49 1. 03 0.031 1. 33 12 10/04/97 15:00 0.639 so 1. 01 0.011 Computed Peaks 2.25 100.00 0. 990 Computed Peaks 2.05 50.00 0.980 Computed Peaks 1. 85 25.00 0. 960 Computed Peaks 1.60 10.00 0.900 Computed Peaks 1.54 8.00 0.875 Computed Peaks 1. 4 0 5.00 0.800 Computed Peaks 1.11 2.00 0.500 Computed Peaks 0. 920 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-244.tsf Mean== 0.350 StdDev-0. 151 Project Location:Sea-Tac Skew-0. 4 63 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 2.43 21 2/16/49 21:00 5 .19 l 89.50 0.989 5.15 2 3/03/50 16:00 5.15 2 32.13 0. 969 B-65 SE 14.f' Streer -June 1007 2.87 10 2/09/51 2:00 4.57 3 19.58 0.949 1. 72 39 1/30/52 8:00 4 .21 4 14.08 0. 929 1. SB 44 3/24/53 15:00 3.54 5 10.99 0.909 2.15 25 12/19/53 19:00 3.44 6 9.01 0.889 2.38 22 2/07/55 17:00 3.19 7 7.64 0.869 2.45 20 12/20/55 17:00 3.06 8 6.63 0.849 2.78 12 12/09/56 14:00 2.89 9 5. 8 6 0.829 2.16 24 12/25/57 16:00 2.87 10 5.24 0.809 1. 61 43 1/26/59 20:00 2.82 11 4.75 0.789 2. 49 19 11/20/59 21:00 2.78 12 4.34 0. 7 69 1. 93 33 2/14/61 21:00 2.76 13 3.99 0.749 1. 65 42 11/22/61 2:00 2.74 14 3.70 0.729 2.00 29 12/15/62 2:00 2. 68 15 3.44 0.709 2. 10 27 12/31/63 23:00 2.63 16 3.22 0.690 1. 78 38 12/21/64 4:00 2.57 17 3.03 0.670 1. 93 34 1/05/66 16:00 2.53 18 2.85 0.650 2.89 9 11/13/66 19:00 2.49 19 2.70 0. 630 2.76 13 8/24/68 16:00 2.45 20 2.56 0.610 1. 83 36 12/03/68 16: 00 2.43 21 2.44 0. 590 1. 96 32 1/13/70 22:00 2.38 22 2.32 0.570 2.00 30 12/06/70 8:00 2.18 23 2.22 0.550 3.54 5 2/27 /72 7:00 2 .16 24 2 .13 0.530 1. 68 40 1/13/73 2:00 2.15 25 2.04 0.510 2 .14 26 11/28/73 9:00 2 .14 26 1. 96 0 .4 90 3.19 7 12/26/74 23:00 2.10 27 1. 89 0.470 1. 87 35 12/02/75 20:00 2.08 28 1. 82 0.450 1. 53 45 8/26/77 2:00 2.00 29 1. 75 0.430 2.57 17 9/22/78 19:00 2.00 30 1. 70 0. 410 1. 67 41 9/08/79 15:00 1. 97 31 1. 64 0.390 2.68 15 12/14/79 21:00 1. 96 32 1. 59 0.370 2.53 18 11/21/80 11:00 1. 93 33 1. 54 0.350 4 .21 4 10/06/81 15:00 1. 93 34 1.49 0.330 2.18 23 10/28/82 16:00 1. 87 35 1. 45 0.310 2.08 28 1/03/84 1:00 1. 83 36 1.41 0. 291 1. 40 46 6/06/85 22: 00 1. 79 37 1.37 0 .271 3.06 8 1/18/86 16: 00 1. 78 38 1.33 0.251 2. 82 11 11/24/86 3:00 ]. 72 39 1. 30 0.231 1. 30 48 1/14/88 12:00 1. 68 40 1.27 0.211 1. 36 47 11/05/88 14:00 1. 67 41 1. 24 0 .191 5.19 l 1/09/90 6:00 1. 65 42 1.21 0.171 4.57 3 11/24/90 8:00 1. 61 43 1.18 0.151 1.97 31 1/27 /92 15:00 1. 58 44 1.15 0.131 1. 28 49 3/22/93 22:00 1.53 45 1.12 0 .111 1. 09 50 11/30/93 22:00 1. 40 46 1.10 0.091 1. 79 37 11/30/94 4:00 1. 36 47 1. 08 0.071 3. 44 6 2/08/96 10:00 1. 30 48 1.05 0.051 2.74 14 1/02/97 6:00 1. 28 49 1. 03 0.031 2.63 16 10/04/97 15:00 1. 09 50 1. 01 0. 011 Computed Peaks 5.65 100.00 0.990 Computed Peaks 4.97 50.00 0. 980 Computed Peaks 4.33 25.00 0. 960 Computed Peaks 3.54 10.00 0.900 Computed Peaks 3.39 8.00 0.875 Computed Peaks 2.97 5.00 0.800 Computed Peaks 2.18 2.00 0.500 Computed Peaks 1. 71 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-250.tsf Mean= 0.048 StdDev-0.126 Project Location:Sea-Tac Skew= 0. 396 B-66 SE I 44"' Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1.18 20 2/16/49 21:00 2 .27 1 89.50 0.989 2.21 2 3/03/50 16: 00 2 .21 2 32.13 0. 969 1.27 18 2/09/51 2:00 2.02 3 19.58 0.949 0.844 44 10/15/51 13:00 1. 88 4 14.08 0.929 0.855 42 3/24/53 15:00 1. 58 5 10.99 0.909 1. 08 26 12/19/53 19:00 1. 55 6 9.01 0.889 1.09 25 11/25/ 54 2:00 1.48 7 7. 64 0.869 1.10 23 12/20/55 17:00 1. 48 8 6. 63 0.849 1.33 14 12/09/56 14:00 1.46 9 5.86 0.829 1.12 21 12/25/57 16: 00 1. 45 10 5.24 0.809 0.817 46 1/26/59 20:00 1. 35 11 4.75 0.789 1.11 22 11/20/59 5: 00 1. 34 12 4.34 0. 769 0. 972 33 2/14/61 21:00 1. 33 13 3.99 0. 749 0.912 39 11/22/61 2:00 1. 33 14 3.70 O. 729 0.982 31 12/15/62 2:00 1. 30 15 3.44 0.709 1.06 28 12/31/63 23:00 1. 30 16 3.22 0.690 0. 941 37 12/21/64 4: 00 1.28 17 3.03 0.670 0.967 35 1/05/66 16:00 1. 27 18 2.85 0.650 1. 48 8 11/13/66 19:00 1. 23 19 2.70 0.630 1.55 6 8/24/68 16:00 1.18 20 2.56 0.610 0.889 41 12/03/68 16:00 1.12 21 2.44 0.590 0. 979 32 1/13/70 22:00 1.11 22 2.32 0.570 0.954 36 12/06/70 8:00 1.10 23 2.22 0. 550 1. 58 5 2/27/72 7:00 1. 09 24 2.13 0.530 0.845 43 1/13/73 2:00 1. 09 25 2.04 0.510 1. 08 27 11/28/73 9:00 1. 08 26 1. 96 0. 490 1. 46 9 12/26/74 23:00 1. 08 27 1. 89 0.470 0.895 40 12/02/75 20:00 1. 06 28 1. 82 0.450 0.936 38 8/26/77 2:00 1. 05 29 1. 75 0.430 1. 35 11 9/22/78 19:00 1. 01 30 1. 70 0.410 1. 09 24 9/08/79 15:00 0.982 31 1.64 0. 390 1. 30 16 12/14/79 21:00 0. 97 9 32 1.59 0.370 1.30 15 11/21/80 11: 00 o. 972 33 1.54 0.350 1. BB 4 10/06/81 15:00 o. 972 34 1. 49 0.330 1. 23 19 10/28/82 16: 00 o. 967 35 1. 45 0.310 1. 05 29 1/03/84 1:00 0.954 36 1. 41 0.291 0.828 45 6/06/85 22:00 0.941 37 1.37 0.271 1. 33 13 1/18/86 16:00 0.936 38 1. 33 0.251 1. 48 7 10/26/86 0:00 0.912 39 1. 30 0.231 0.646 49 1/14/88 0:00 0. 895 40 1.27 0 .211 0.774 47 8/21/89 17:00 0.889 41 1.24 0.191 2.27 1 1/09/90 6:00 0.855 42 1.21 0.171 2. 02 3 11/24/90 8:00 0.845 43 1.18 0.151 1. 01 30 1/27 /92 15:00 0.844 44 1.15 0 .131 0. 600 50 12/10/92 6:00 0.828 45 1.12 0 .111 0.689 48 11/30/93 22:00 0.817 46 1.10 0.091 0. 972 34 11/30/94 4: 00 o. 774 47 1. 08 0 .071 1. 45 10 2/08/96 10:00 0.689 48 1. 05 0.051 1.28 17 1/02/97 6:00 0. 646 49 1. 03 0.031 1. 34 12 10/04/97 15:00 0.600 50 1. 01 0 .011 Computed Peaks 2.39 100.00 0.990 Computed Peaks 2.16 50.00 0.980 Computed Peaks 1. 93 25.00 0. 960 Computed Peaks 1. 64 10.00 0.900 Computed Peaks 1. 58 8.00 0.875 Computed Peaks 1. 42 5. 00 0.800 B-67 SE 14¢1'Street~June2007 Computed Peaks 1. 10 2.00 0. 500 Computed Peaks 0. 8 93 1. 30 0.231 Flow Frequency Analysis LogPearson I I I Coefficients Time Series File:c-260.tsf Mean= -0.230 StdDev-0.124 Project Location:Sea-Tac Skew= 0.395 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.617 20 2/16/49 21:00 1.18 1 89.50 0.989 1.14 2 3/03/50 16:00 1.14 2 32.13 0. 969 0.660 18 2/09/51 2: 00 1. 05 3 19.58 0.949 0.449 43 10/15/51 13:00 0.977 4 14.08 0.929 0. 4 52 42 3/24/53 15:00 0.824 5 10.99 0.909 0.567 26 12/19/53 19:00 0.819 6 9.01 0.889 0.572 25 11/25/54 2:00 0.788 7 7.64 0.869 0.574 24 12/20/55 17: 00 0. 777 8 6.63 0.849 0.695 13 12/09/56 14:00 0. 760 9 5.86 0 .829 0.590 21 12/25/57 16: 00 0.752 10 5.24 0. 809 0.430 46 11/18/58 13:00 0. 711 11 4.75 0.789 0.581 23 11/20/59 5:00 0.704 12 4.34 0.769 0.511 34 2/14/61 21:00 0.695 13 3.99 0.749 0.483 39 11/22/61 2:00 0.695 14 3. 70 0. 729 0.515 31 12/15/62 2:00 0.687 15 3.44 0. 709 0.561 28 12/31/63 23:00 0.681 16 3.22 0. 690 0. 4 97 38 12/21/64 4:00 0.668 17 3.03 0.670 0.509 35 1/05/66 16:00 0.660 18 2.85 0.650 0. 777 8 11/13/66 19:00 0.655 19 2.70 0.630 0.819 6 8/24/68 16:00 0.617 20 2.56 0.610 0. 4 67 41 12/03/68 16:00 0.590 21 2.44 0. 5 90 0.515 32 1/13/70 22:00 0.584 22 2.32 0.570 0.500 36 12/06/70 8:00 0.581 23 2.22 0.550 0.824 5 2/27 /72 7:00 0.574 24 2.13 0. 530 0.445 44 1/13/73 2:00 0.572 25 2.04 0.510 0. 564 27 11/28/73 9:00 0.567 26 1. 96 0. 490 0.760 9 12/26/74 23:00 0.564 27 1. 89 0.470 0.470 40 12/02/75 20:00 0.561 28 1. 82 0. 450 0.499 37 8/2 6/77 2:00 0.550 29 1. 75 0.430 0. 711 11 9/22/78 19: 00 0.531 30 1. 70 0.410 0.584 22 9/08/79 15:00 0.515 31 1. 64 0.390 0.681 16 12/14/79 21:00 0.515 32 1.59 0.370 0.687 15 11/21/80 11:00 0.514 33 1.54 0.350 0.977 4 10/06/81 15:00 0.511 34 1. 49 0.330 0.655 19 10/28/82 16: 00 0. 50 9 35 1.45 0.310 0.550 29 1/03/84 1:00 0.500 36 1. 41 0.291 0.440 45 6/06/85 22:00 0.499 37 1. 37 0.271 0.695 14 1/18/86 16:00 0.497 38 1. 33 0.251 0.788 7 10/26/86 0:00 0. 483 39 1.30 0.231 0.343 49 1/14/88 0:00 0. 470 40 1.27 0. 211 0.417 47 8/21/89 17:00 0. 4 67 41 1.24 0 .191 1.18 1 1/09/90 6:00 0.452 42 1. 21 0.171 1.05 3 11/24/90 8:00 0. 44 9 43 1.18 0.151 0.531 30 1/27/92 15:00 0. 445 44 1.15 0 .131 0.318 50 12/10/92 6:00 0.440 45 1.12 0 .111 0.368 48 11/30/93 22:00 0.430 46 1.10 0. 091 0.514 33 11/30/94 4:00 0 .417 47 1.08 0.071 0.752 10 2/08/96 10:00 0.368 48 1. 05 0.051 0.668 17 1/02/97 6:00 0.343 49 1. 03 0.031 0.704 12 10/04/97 15:00 0.318 50 1. 01 0. 011 B-68 SE 144'" Street-June 2007 Computed Peaks 1. 24 100.00 0.990 Computed Peaks 1.12 50.00 0.980 Computed Peaks 1. 01 25.00 0. 9 60 Computed Peaks 0.857 10.00 0.900 Computed Peaks 0.827 8.00 0.875 Computed Peaks 0.743 5.00 0.800 Computed Peaks 0.577 2.00 0.500 Computed Peaks 0.472 1. 30 0. 2 31 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-260rd.tsf Mean= -0.785 StdDev= 0. 291 Project Location:Sea-Tac Skew= 1.218 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.133 36 2/22/49 6:00 1.19 5.21 1 89.50 0.989 0 .17 9 14 3/05/50 7:00 0.942 5.17 2 32.13 0. 969 0. 942 2 2/09/51 16:00 0.932 5 .17 3 19.58 o. 94 9 0.081 42 2/04/52 9: 00 0. 577 5 .11 4 14.08 0.929 o. 152 25 1/12/53 7:00 0.543 5.10 5 10.99 0.909 o .145 31 1/06/54 12:00 0.439 5.07 6 9.01 0.889 0.135 35 2/08/55 15:00 0.303 5.03 7 7. 64 0.869 o .191 11 12/22/55 16:00 0.225 5.00 8 6.63 0. 84 9 0.142 33 2/26/57 4:00 0.209 4.99 9 5.86 0.829 o .171 18 1/17/58 8:00 0.200 4.74 10 5.24 0.809 o .125 39 1/24/59 18:00 0 .191 4.51 11 4.75 0.789 0.577 4 11/21/59 2:00 0.183 4.32 12 4.34 0.769 0.168 19 11/24/60 17:00 0.181 4.29 13 3.99 0. 749 0. 072 45 12/24/61 6:00 0.179 4 .22 14 3.70 0. 729 0 .156 22 11/26/62, 11: 00 0 .178 4.21 15 3. 44 0.709 0 .152 26 11/19/63 18:00 0 .173 4 .11 16 3.22 0.690 0.183 12 12/01/64 8:00 0.172 4.08 17 3.03 0.670 0.140 34 1/07/66 3:00 0 .171 4.07 18 2.85 0.650 0.172 17 12/13/66 15:00 0 .168 4.00 19 2.70 0.630 0 .150 27 1/20/68 20: 00 0 .162 3.89 20 2.56 0. 610 0.133 37 12/11/68 7:00 0 .162 3.87 21 2.44 0.590 0.145 32 1/27/70 4:00 0.156 3.77 22 2.32 0.570 0.153 24 12/07/70 11 :OD 0.155 3.74 23 2.22 0.550 0.209 9 3/07 /72 1:00 0.153 3. 71 24 2.13 0.530 0.173 16 12/27/72 19:00 0.152 3.69 25 2.04 0.510 0 .155 23 1/16/74 19:00 0.152 3.68 26 1. 96 0. 4 90 0.127 38 1/13/75 23:00 0.150 3.65 27 1. 89 0.470 0 .150 28 12/04/75 4:00 0.150 3. 65 28 1.82 0.450 0. 061 50 8/26/77 7:00 0.147 3.59 29 1. 75 0.430 0 .162 20 12/15/77 19:00 0.146 3.57 30 1. 70 0.410 0.066 48 2/13/79 12:00 0 .145 3.56 31 1. 64 0.390 0.543 5 12/17 /7 9 18:00 0 .145 3.56 32 1. 59 0.370 0.147 29 12/30/80 21:00 0.142 3.52 33 1. 54 0.350 0.200 10 10/07/81 1:00 0 .140 3.48 34 1. 4 9 0.330 0.146 30 1/06/83 14:00 0.135 3.40 35 1.45 0.310 0.073 44 12/13/83 5:00 0.133 3.38 36 1. 41 0.291 0.074 43 11/04/84 9:00 0.133 3.38 37 1. 37 o. 271 0.181 13 1/19/86 11:00 0.127 3.28 38 1. 33 0.251 0.225 8 11/24/86 14:00 0.125 3.27 39 1. 30 0.231 0.109 40 12/09/87 23:00 0.109 3.09 40 1.27 0 .211 0. 071 46 11/06/88 0:00 0.105 3.04 41 1. 24 0 .191 1.19 1 1/09/90 10:00 0.081 2. 96 42 1. 21 0 .171 0.303 7 4/05/91 7:00 0. 074 2. 91 43 1.18 0.151 0 .162 21 1/31/92 6:00 0.073 2.86 44 1.15 0.131 B-69 SE 14.f' Stree1-June 2007 0.070 47 1/26/93 6:00 0.072 2.80 45 1.12 0 .111 0.062 49 2/17/94 23:00 0. 071 2.74 46 1.10 0. 091 0 .178 15 12/27/94 20:00 0.070 2. 60 47 1. 08 0. 071 0.932 3 2/09/96 2:00 0.066 2.38 48 1. 05 0.051 0.439 6 1/02/97 12:00 0. 062 2 .13 49 1. 03 0.031 0.105 41 1/24/98 23:00 0.061 1. 99 50 1. 01 0. 011 Computed Peaks 1.36 5.24 100.00 0.990 Computed Peaks 0.959 5.18 50.00 0.980 Computed Peaks 0.666 5 .13 25.00 0 .960 Computed Peaks 0.403 5.06 10.00 0.900 Computed Peaks 0.364 5.05 8.00 0.875 Computed Peaks 0. 268 5.02 5.00 0.800 Computed Peaks 0.144 3.54 2.00 0.500 Computed Peaks 0.097 3.01 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-270.tsf Mean= -0.263 StdDev-0.125 Project Location:Sea-Tac Skew-0. 392 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.573 20 2/16/49 21:00 1.10 1 89.50 0.989 1. 06 2 3/03/50 16:00 1. 06 2 32.13 0. 969 0.614 18 2/09/51 2:00 0.982 3 19.58 0.949 0.415 43 10/15/51 13:00 0.910 4 14.08 0.929 0.419 42 3/24/53 15:00 0.768 5 10.99 0.909 0.526 26 12/19/53 19:00 0.758 6 9.01 0. 8 89 0.530 25 11/25/54 2:00 0. 728 7 7.64 0. 8 69 0.534 24 12/20/55 17:00 0.721 8 6.63 0.849 0.646 14 12/09/56 14:00 0.707 9 5.86 0.829 0.547 21 12/25/57 16:00 0.701 10 5.24 0.809 0.399 46 1/26/59 20:00 0.659 11 4.75 0.789 0.540 22 11/20/59 5:00 0. 653 12 4.34 0.769 0.474 34 2/14/61 21:00 0. 647 13 3.99 0.749 0.447 39 11/22/61 2:00 0. 64 6 14 3.70 0.729 0.479 31 12/15/62 2:00 0.637 15 3.44 0.709 0.520 28 12/31/63 23:00 0.633 16 3.22 0.690 0. 4 60 38 12/21/64 4:00 0.622 17 3.03 0.670 0.472 35 1/05/66 16:00 0.614 18 2.85 0.650 o. 721 8 11/13/66 19:00 0.606 19 2.70 0. 630 0.758 6 8/24/68 16:00 0.573 20 2.56 o. 610 a. 433 41 12/03/68 16:00 0.547 21 2.44 0.590 0. 478 32 1/13/70 22:00 0.540 22 2.32 0.570 0. 4 64 36 12/06/70 8: 00 0.539 23 2.22 0.550 0.768 5 2/27 /72 7:00 0.534 24 2.13 0.530 0. 413 44 1/13/73 2:00 0.530 25 2.04 0.510 0.524 27 11/28/73 9:00 0.526 26 1.96 0.490 0.707 9 12/26/74 23:00 0.524 27 1. 89 0.470 o. 436 40 12/02/75 20:00 0.520 28 1.82 0.450 o. 461 37 8/26/77 2:00 0.510 29 1. 75 0.430 0.659 11 9/22/78 19: 00 0.492 30 1. 70 0.410 0.539 23 9/08/79 15:00 0.479 31 1. 64 0.390 0.633 16 12/14/79 21:00 0.478 32 1.59 0. 37 0 0.637 15 11/21/80 11:00 0 .476 33 1. 54 0.350 0. 910 4 10/06/81 15:00 0. 474 34 1.4 9 0.330 0.606 19 10/28/82 16: 00 0 .472 35 1. 45 0.310 0.510 29 1/03/84 1:00 0. 4 64 36 1. 41 0.291 0.407 45 6/06/85 22:00 o. 4 61 37 1. 37 0. 271 0.647 13 1/18/86 16:00 o. 460 38 1.33 0.251 B-70 SE 14.fn Street-June 2007 0. 728 7 10/26/86 0:00 0.447 39 1.30 0.231 0.317 49 1/14/88 0:00 0.436 40 1. 27 0. 211 0.383 47 8/21/89 17:00 0. 433 41 1.24 0 .191 1.10 1 1/09/90 6:00 0. 419 42 1.21 0.171 0.982 3 11/24/90 8:00 0.415 43 1.18 0.151 0. 4 92 30 1/27/92 15:00 0.413 44 1.15 0.131 0. 294 50 12/10/92 6:00 0.407 45 1.12 0 .111 0.339 48 11/30/93 22: 00 0.399 46 1.10 0. 091 0.476 33 11/30/94 4:00 0.383 47 1.08 0.071 0.701 10 2/08/96 10:00 0.339 48 1.05 0. 051 0.622 17 1/02/97 6:00 0.317 49 1. 03 0.031 0.653 12 10/04/97 15:00 0.294 50 1. 01 0. 011 Computed Peaks 1.16 100.00 0.990 Computed Peaks 1. 04 50.00 0.980 Computed Peaks 0.936 25.00 0. 960 Computed Peaks 0.797 10.00 0.900 Computed Peaks 0.769 8.00 0.875 Computed Peaks 0.690 5.00 0.800 Computed Peaks 0.536 2.00 0.500 Computed Peaks 0.437 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-300.tsf Mean= -0. 057 StdDev~ 0.172 Project Location:Sea-Tac Skew= 0.335 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 02 17 2/16/49 21:00 2.19 1 89. 50 0. 989 2.17 2 3/03/50 16:00 2.17 2 32.13 o. 969 1.35 8 2/09/51 14:00 1. 90 3 19. 58 0. 94 9 0. 718 38 1 /30/52 8:00 1.58 4 14.08 0. 929 0.602 42 3/24/53 15:00 1.58 5 10.99 0. 909 0.842 21 12/19/53 19:00 1.50 6 9.01 0.889 1. 05 16 2/07/55 17:00 1. 36 7 7.64 0.869 1. 08 15 12/20/55 17 :00 1.35 8 6.63 0. 849 1.11 14 12/09/56 14:00 1.32 9 5.86 0.829 0.796 27 12/25/57 16:00 1.20 10 5.24 0.809 0.644 41 1/26/59 20:00 1. 20 11 4.75 0. 789 1.14 13 11/20/59 21: 00 1.15 12 4.34 0.769 0. 775 32 2/14/61 21:00 1.14 13 3.99 0.749 0.543 45 11/22/61 2:00 1.11 14 3.70 0.729 0. 791 29 12/15/62 2:00 1.08 15 3.44 0.709 0.838 22 12/31/63 23:00 1. 05 16 3.22 0.690 0.672 40 12/21/64 4:00 1. 02 17 3.03 0.670 0. 771 34 1/05/66 16:00 1.02 18 2.85 0.650 1.20 11 1/19/67 14: 00 0. 919 19 2.70 0.630 0. 919 19 B/24/68 16:00 0.855 20 2.56 0.610 0.763 35 12/03/68 16:00 0.842 21 2.44 0.590 0.775 31 1/13/70 23:00 0.838 22 2.32 0.570 0.774 33 12/06/70 8:00 0.831 23 2.22 0.550 1. 50 6 2/27 /72 7:00 0.829 24 2 .13 0.530 0.686 39 1/13/73 2: 00 0.815 25 2.04 0.510 0.793 28 11/28/73 9:00 0.807 26 1. 96 0. 490 1.32 9 12/26/74 23:00 0.796 27 1. 89 0.470 0. 782 30 12/02/75 20:00 0.793 28 1. 82 0.450 0.512 47 8/26/77 2:00 0. 791 29 1. 75 0. 430 0. 829 24 9/22/78 19:00 0.782 30 1. 70 0.410 0.563 44 9/08/79 15:00 0.775 31 1. 64 0.390 1.02 18 12/14/79 21:00 0. 775 32 1. 59 0.370 B-71 SE 144°' Stree1-June 2007 0.831 23 11/21/80 11: 00 0. 774 33 1. 54 0. 350 1.58 4 10/06/81 15:00 0.771 34 1. 49 0.330 0.807 26 1/05/83 8:00 0.763 35 1.45 0. 310 0.815 25 1/03/84 1:00 0.762 36 1. 41 0. 291 0.469 48 6/06/85 22:00 0.759 37 1. 37 0. 271 1.36 7 1/18/86 16:00 0.718 38 1.33 0. 251 1.20 10 11/24/86 3:00 0. 686 39 1. 30 0 .231 0.539 46 1/14/88 12:00 0.672 40 1. 27 0. 211 0.444 49 11/05/88 14:00 0.644 41 1. 24 0 .191 2.19 1 1/09/90 6 :00 0.602 42 1.21 0 .1 71 1. 90 3 11/24/90 8:00 0.568 43 1.18 0 .151 0.759 37 1/27 /92 17:00 0.563 44 1.15 0.131 0.568 43 3/22/93 22:00 0.543 45 1.12 0.111 0.368 50 11/30/93 22:00 0.539 46 1.10 0. 091 0.762 36 2/18/95 20:00 0.512 47 1. 08 0.071 1.58 5 2/08/96 10:00 0.469 48 1.05 0.051 1.15 12 1/02/97 6:00 0.444 49 1. 03 0. 031 0.855 20 10/04/97 15:00 0.368 50 1. 01 0.011 Computed Peaks 2.42 100.00 0. 990 Computed Peaks 2.12 50.00 0.980 Computed Peaks 1. 83 25.00 0.960 Computed Peaks 1. 47 10.00 0.900 Computed Peaks 1. 40 8.00 0. 875 Computed Peaks 1. 21 5.00 0.800 Computed Peaks 0.859 2.00 0.500 Computed Peaks 0.647 1. 30 0 .231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-304.tsf Mean= 0.141 StdDev= 0.132 Project Location:Sea-Tac Skew= 0. 426 ---Annual Peak Flow Rates--------Flow Frequency Analysis---~--- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 49 19 2/16/49 21: 00 2. 93 1 89.50 0.989 2. 8 6 2 3/03/50 16:00 2. 86 2 32.13 0.969 1. 65 13 2/09/51 2:00 2. 61 3 19. 58 0. 94 9 1. 06 42 1 /30/ 52 8:00 2.38 4 14.08 0. 929 1. 04 44 3/24/53 15:00 2.04 5 10.99 0.909 1. 34 25 12/19/53 19:00 1. 92 6 9.01 0.889 1. 40 22 2/07/55 17:00 1. 86 7 7. 64 0.869 1.42 21 12/20/55 17: 00 1. 84 8 6.63 0.849 1. 67 12 12/09/56 14:00 1. 78 9 5.86 0.829 1. 37 24 12/25/57 16:00 1. 75 10 5.24 0.809 1. 01 45 1/26/59 20:00 1. 74 11 4.75 0.789 1. 40 23 11/20/59 5:00 1. 67 12 4.34 0.769 1.21 33 2/14/61 21:00 1. 65 13 3.99 0.749 1. 09 41 11/22/61 2:00 1. 63 14 3.70 0. 729 1.23 31 12/15/62 2:00 1. 62 15 3.44 0.709 1. 32 26 12/31/63 23:00 1. 62 16 3.22 0.690 1.15 37 12/21/64 4:00 1. 62 17 3.03 0.670 1. 20 34 1/05/66 16:00 1. 58 18 2.85 0.650 1.78 9 11/13/66 19:00 1. 49 19 2.70 0.630 1. 84 8 8/24/68 16:00 1. 47 20 2.56 0.610 1.12 39 12/03/68 16:00 1.42 21 2.44 0. 590 1.22 32 1/13/70 22:00 1. 40 22 2.32 0.570 1. 20 35 12/06/70 8:00 1. 40 23 2.22 0.550 2.04 5 2/27 /72 7:00 1.37 24 2 .13 0.530 1. 06 43 1/13/73 2:00 1. 34 25 2.04 0.510 1. 32 27 11/28/73 9:00 1. 32 26 1. 96 0.490 B-72 SE 14¢3' Street-June 2007 1. 86 7 12/26/74 23:00 1. 32 27 1. 89 0.470 1.14 38 12/02/75 20:00 1. 30 28 1. 82 0.450 1.10 40 8/26/77 2:00 1.27 29 1. 75 0.430 1. 62 15 9/22/78 19:00 1. 24 30 1. 70 0.410 1. 27 29 9/08/79 15: 00 1. 23 31 1. 64 0. 390 1. 62 17 12/14/79 21:00 1. 22 32 1. 59 0.370 1.58 18 11/21/80 11 :00 1.21 33 1. 54 0.350 2.38 4 10/06/81 15:00 1.20 34 1. 49 0 .330 1.47 20 10/28/82 16:00 1.20 35 1. 45 0.310 1. 30 28 1/03/84 1: 00 1.17 36 1. 41 0. 2 91 0. 978 46 6/06/85 22:00 1.15 37 1. 37 0. 271 1. 75 10 1/18/86 16: 00 1.14 38 1. 33 0.251 1. 74 11 10/26/86 0:00 1.12 39 1. 30 0. 2 31 0.782 49 1/14/88 12:00 1.10 40 1. 27 0. 211 0.897 47 8/21/89 17:00 1. 09 41 1.24 0 .191 2. 93 1 1/09/90 6:00 1. 06 42 1.21 0 .171 2. 61 3 11/24/90 8:00 1. 06 43 1.18 0.151 1.24 30 1/27/92 15:00 1.04 44 1.15 0 .131 0.756 50 3/22/93 22:00 1. 01 45 1.12 0.111 0.806 48 11/30/93 22:00 0.978 46 1.10 0.091 1.17 36 11/30/94 4:00 0.897 47 1.08 0. 071 1. 92 6 2/08/96 10:00 0.806 48 1. 05 0.051 1. 63 14 1/02/97 6:00 0.782 49 1. 03 0.031 1. 62 16 10/04/97 15:00 0.756 50 1.01 0. 011 Computed Peaks 3.09 100.00 0.990 Computed Peaks 2. 77 50.00 0.980 Computed Peaks 2.46 25.00 0. 960 Computed Peaks 2.07 10.00 0.900 Computed Peaks 1. 99 8.00 0.875 Computed Peaks 1. 77 5.00 0. 800 Computed Peaks 1. 36 2.00 0.500 Computed Peaks 1. 09 1. 30 0.231 Flow Frequency Analysis Log Pearson III Coefficients Time Series File:c-306 .. tsf Mean= -1.180 StdDev-0.204 Project Location:Sea-Tac Skew-0.041 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.081 17 2/16/49 21:00 0.177 1 89.50 0. 989 0.176 2 3/03/50 16:00 0.176 2 32.13 0.969 0.126 5 2/09/51 15:00 0.153 3 19. 58 0. 94 9 0.056 37 1/30/52 8:00 0.136 4 14. 08 0. 929 0.042 44 3/24/53 15:00 0.126 5 10.99 0.909 0.062 23 12/19/53 19:00 0.122 6 9.01 0.889 0.087 15 2/07/55 19:00 0.118 7 7. 64 0.869 0.089 14 12/20/55 17:00 0 .115 8 6.63 0.849 0.085 16 12/09/56 14 :00 0.104 9 5.86 0.829 0.064 21 1/16/58 16:00 0.100 10 5.24 0.809 0.052 40 1/23/59 23:00 0.100 11 4.75 0.789 0.100 10 11/20/59 21:00 0.100 12 4.34 0.769 0.058 31 2/14/61 21:00 0. 092 13 3.99 0.749 0.037 45 1 / 02 / 62 22:00 0.089 14 3.70 0. 729 0.059 30 12/15/62 2:00 0.087 15 3.44 0.709 0.062 22 12/31/63 23:00 0.085 16 3.22 0.690 0.047 42 12/21/64 4:00 0.081 17 3.03 0.670 0.058 32 1/05/66 16:00 0.073 18 2.85 0.650 0.100 11 1/19/67 14:00 0. 0 69 19 2.70 0. 630 0.060 25 2/03/68 22:00 0. 0 67 20 2.56 0. 610 B-73 SE 144"' Street-June 2007 0. 060 27 12/03/68 16:00 0.064 21 2.44 0.590 0.060 28 1/13/70 23:00 0.062 22 2. 32 0.570 0.058 33 12/06/70 8:00 0.062 23 2.22 0.550 0.122 6 2/28/72 3:00 0.061 24 2 .13 0.530 0.053 38 1/13/73 4:00 0.060 25 2. 04 0.510 0.057 34 1/15/74 2:00 0.060 26 1. 96 0.490 0.104 9 12/26/74 23:00 0.060 27 1. 89 0.470 0. 061 24 12/02/75 20:00 0.060 28 1. 82 0.450 0.029 48 8/26/77 2:00 0.059 29 1. 75 0. 430 0.057 35 12/10/77 17: 00 0.059 30 1. 70 0.410 0.031 47 11/19/78 3:00 0.058 31 1. 64 0.390 0.073 18 12/14/79 21:00 0.058 32 1. 59 0.370 0.056 36 12/26/80 0:00 0.058 33 1. 54 0.350 0 .118 7 10/06/81 15:00 0.057 34 1. 49 0.330 0.069 19 1/05/83 8:00 0.057 35 1. 45 0.310 0.060 26 1/03/84 1:00 0.056 36 1. 41 0. 291 0.031 46 2/11/85 3:00 0.056 37 1. 37 0.271 0.115 8 1/18/86 16: DO 0.053 38 1.33 0.251 0.100 12 11/24/86 4:00 0.052 39 1.30 0. 231 0.043 43 1/14/88 12:00 0.052 40 1.27 0.211 0.027 49 12/30/88 5:00 0.048 41 1.24 0 .191 0.177 1 1/09/90 6:00 0.047 42 1.21 0 .171 0.153 3 11/24/90 8:00 0.043 43 1. 18 0.151 0.059 29 1/27 / 92 17:00 0.042 44 1.15 0.131 0.048 41 3/22/93 23:00 0.037 45 1.12 0 .111 0.023 50 2/17/94 18:00 0.031 46 1.10 0.091 0.067 20 2/19/95 18:00 0.031 47 1. 08 0.071 0 .136 4 2/08/ 96 10:00 0. 02 9 48 1. 05 0.051 0.092 13 1/02/97 6:00 0. 027 49 1. 03 0.031 0.052 39 10/04/97 15:00 0.023 50 1. 01 0. 011 Computed Peaks 0.200 100.00 0.990 Computed Peaks 0.176 50.00 0.980 Computed Peaks 0.152 25.00 0. 960 Computed Peaks 0.121 10.00 0. 900 Computed Peaks 0.115 8.00 0.875 Computed Peaks 0.098 5.00 0.800 Computed Peaks 0.066 2.00 0.500 Computed Peaks 0.046 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-310.tsf Mean= -0. 648 StdDev= 0.233 Project Location:Sea-Tac Skew= -0.139 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.276 16 2/16/49 22:00 0.627 1 89.50 0. 989 0.539 5 3/03/50 16:00 0.592 2 32 .13 0. 969 0 .592 2 2/09/51 18:00 0.561 3 19.58 0. 949 0.186 32 1/30/52 9:00 0.549 4 14. 08 0. 929 0.143 42 1/18/53 19:00 0.539 5 10.99 0. 909 0.208 28 1/06/54 5:00 0. 456 6 9.01 0.889 0.368 9 2/07/55 21:00 0. 440 7 7.64 0.869 0. 313 13 12/20/55 17:00 0.396 8 6.63 0.849 0.244 21 12/09/56 15:00 0.368 9 5.86 0. 829 0.259 20 1/16/58 20:00 0.368 10 5.24 0.809 0.212 24 1/24/59 2:00 0. 364 11 4.75 0. 789 0. 396 8 11/20/59 21 :00 0. 317 12 4. 34 0. 769 0. 215 23 2/24/61 15:00 0. 313 13 3.99 0.749 0.129 44 1/03/62 2:00 0.306 14 3.70 0.729 B-74 SE 14¢1' Street-June 2007 0 .171 36 11/25/62 15:00 0.285 15 3. 4 4 0.709 0.212 25 1/01/64 18:00 0.276 16 3.22 0.690 0 .150 40 11/30/64 12:00 0.273 17 3.03 0.670 0.163 38 1/06/66 3:00 0.273 18 2. 85 0.650 0.364 11 1/19/67 14 :00 0.265 19 2.70 0.630 0 .216 22 2/03/68 23:00 0.259 20 2.56 0.610 0 .211 27 12/03/68 17: 00 0.244 21 2.44 0.590 0.179 34 1/13/70 23:00 0.216 22 2.32 0.570 0.145 41 12/06/70 8:00 0.215 23 2.22 0.550 0. 440 7 2 /28/72 3:00 0.212 24 2 .13 0.530 0.195 30 1/13/73 5:00 0.212 25 2.04 0.510 0.212 26 1/15/74 2:00 0.212 26 1. 96 0.490 0.317 12 12/26/74 23:00 0.211 27 1. 89 0.470 0.196 29 l 2 /03/7 5 17:00 0.208 28 1. 82 0.450 0.022 50 3/24/77 20:00 0 .196 29 1. 75 0.430 0.169 37 12/10/77 17:00 0.195 30 1. 70 0.410 0.102 46 2/12/79 8:00 0 .190 31 1.64 0. 390 0.273 18 12/15/79 8:00 0.186 32 1.59 0.370 0.151 39 12/26/80 4:00 0.183 33 1. 54 0.350 0.273 17 10/06/81 15:00 0.179 34 1. 49 0.330 0.265 19 1/05/83 8:00 0.177 35 1. 45 0.310 0.177 35 1/24/84 11: 00 0.171 36 1. 41 0. 2 91 0.085 48 2/11/85 6:00 0.169 37 1. 37 0.271 0.456 6 1/18/86 21:00 0.163 38 1. 33 0.251 0.368 10 11/24/86 4:00 0.151 39 1. 30 0.231 0.139 43 1/14/88 12:00 0.150 40 1.27 0.211 0.088 47 4/05/89 16:00 0.145 41 1. 24 0 .191 0.627 1 1/09/90 9:00 0.143 42 1. 21 0.171 0. 54 9 4 4/05/91 2:00 0.139 43 1.18 0.151 0.183 33 1/27/92 17:00 0.129 44 1.15 0.131 0.190 31 3/23/93 0:00 0.107 45 1.12 0.111 0.053 49 3/03/94 4:00 0.102 46 1.10 0.091 0.285 15 2/19/95 20:00 0.088 47 1. 08 0.071 0.561 3 2/09/96 1:00 0.085 48 1. 05 0.051 0.306 14 1/02/97 9:00 0.053 49 1. 03 0.031 0 .107 45 1/07/98 10:00 0.022 50 1. 01 0. 011 Computed Peaks 0. 743 100.00 0.990 Computed Peaks 0.651 50.00 0.980 Computed Peaks 0. 561 25.00 0.960 Computed Peaks 0.444 10.00 0.900 Computed Peaks ·o. 420 8.00 0.875 Computed Peaks 0.355 5.00 0.800 Computed Peaks 0.228 2.00 0.500 Computed Peaks 0.151 1.30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File: c-320. tsf Mean= -0.597 StdDev-0 .22 6 Project Location:Sea-Tac Skew--0.141 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.312 16 2/16/49 22:00 o. 692 1 89.50 0.989 0.636 2 3/03/50 16:00 0.636 2 32.13 0. 969 0. 621 3 2/09/51 18:00 0.621 3 19. 58 0. 949 0.207 33 1/30/52 8:00 0.595 4 14.08 0. 929 0 .161 42 1/18/53 19:00 0.586 5 10.99 0.909 0.223 29 1/22/54 20:00 0. 495 6 9.01 0.889 0. 392 11 2/07/55 21:00 0. 4 85 7 7. 64 0.869 0. 354 14 12/20/55 17 :00 0 .434 8 6.63 0.849 B-75 SE 144°' Srreet-June 2007 0.284 20 12/09/56 14:00 0. 411 9 5.86 0.829 0 .275 21 1/16/58 20:00 0.408 10 5.24 0.809 0.227 28 1/24/59 2:00 0. 392 11 4.75 0.789 0.434 8 11/20/59 21:00 0.375 12 4.34 0.769 0 .227 26 2/24/61 15:00 0.356 13 3.99 0.749 0.142 44 1/02/62 22:00 0.354 14 3.70 0.729 0 .192 36 11/25/62 14:00 0.339 15 3.44 0. 709 0.234 25 1/01/64 14:00 0.312 16 3.22 0. 690 0 .167 41 11/30/64 22:00 0.301 17 3.03 0.670 0.191 37 1/05/66 16:00 0.295 18 2.85 0.650 0.408 10 1/19/67 14:00 0.293 19 2.70 0.630 0.239 22 2/03/68 22: 00 0.284 20 2 .. 56 0.610 0.237 23 12/03/68 17:00 0. 275 21 2.44 0 .590 0.212 32 1/13/70 23:00 0.239 22 2.32 0.570 0.183 39 12/06/70 8:00 0.237 23 2.22 0.550 0.495 6 2/28/72 3:00 0.235 24 2 .13 0. 530 0.215 30 1/13/73 5:00 0. 234 25 2.04 0.510 0.235 24 1/15/74 2:00 0 .227 26 1.96 0. 4 90 0.375 12 12/26/74 23:00 0.227 27 1.89 0 .470 0.227 27 12/02/75 20:00 0.227 28 1.82 0 .450 0.047 50 3/24/77 19:00 0.223 29 1. 75 0. 430 0.201 35 12/10/77 17: 00 0.215 30 1. 70 0.410 0 .114 46 2/12/79 7:00 0.215 31 1. 64 0.390 0.295 18 12/15/79 8:00 0.212 32 1. 59 0.370 0.180 40 12/26/80 0:00 0.207 33 1. 54 0.350 0.356 13 10/06/81 15:00 0.207 34 1. 4 9 0.330 0 .293 19 1/05/83 8:00 0.201 35 1. 45 0.310 0.190 38 1/24/84 11: 00 0 .192 36 1. 41 0. 2 91 0.095 48 2/11/85 5:00 0 .191 37 1.37 0 .2 71 0.485 7 1/18/86 20:00 0 .190 38 1. 33 0.251 0. 411 9 11/24/86 4:00 0.183 39 1.30 0.231 0.161 43 1/14/88 12:00 0.180 40 1.27 0.211 0.098 47 4/05/89 16:00 0.167 41 1.24 0.191 0.692 1 1/09/90 9:00 0 .161 42 1. 21 0.171 0.586 5 4/05/91 2: 00 0 .161 43 1.18 0.151 0.215 31 1/27 /92 17: 00 0.142 44 1.15 0.131 0.207 34 3/22/93 23:00 0.132 45 1.12 0 .111 0.063 49 2/17 /94 18:00 0 .114 46 1.10 0.091 0.301 17 2/19/95 18:00 0.098 47 1. 08 0.071 0.595 4 2/09/96 1:00 0.095 48 1. 05 0.051 0.339 15 1/02/97 9:00 0.063 49 1. 03 0.031 0.132 45 10/30/97 7:00 0.047 50 1. 01 0. 011 Computed Peaks 0.806 100.00 0.990 Computed Peaks 0. 709 50.00 0.980 Computed Peaks 0 .614 25.00 0. 960 Computed Peaks 0.489 10.00 0.900 Computed Peaks 0. 4 63 8.00 0.875 Computed Peaks 0.394 5.00 0.800 Computed Peaks 0.256 2.00 0.500 Computed Peaks 0 .171 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:c-330.tsf Mean= -0.930 StdDev-0.187 Project Location:Sea-Tac Skew-0 .198 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.139 17 2/16/49 21:00 0.307 1 89.50 0.989 0.307 2 3/03/50 16:00 0.307 2 32.13 O. 969 B-76 SE 14,/1 Street-June 1007 0.193 7 2/09/51 14 :00 0.265 3 19. 58 0.949 0.097 38 1/30/52 8:00 0.222 4 14. 08 0.929 0.078 43 3/24/53 15:00 0 .218 5 10.99 0.909 0.112 20 12/19/53 19: 00 0.208 6 9.01 0.889 0.144 16 2/07/55 17:00 0 .193 7 7. 64 0. 8 69 0 .14 9 15 12/20/55 17:00 0.190 8 6.63 0.849 0.152 14 12/09/56 14:00 0.182 9 5.86 0.829 0.107 26 1 /16 / 58 16:00 0. 167 10 5.24 0.809 0.087 41 1/23/59 23:00 0.166 11 4.75 0.789 0.162 12 11/20/59 21:00 0 .162 12 4.34 0. 7 69 0.103 34 2/14/61 21:00 0.158 13 3.99 0.749 0.068 45 11/22/61 2:00 0.152 14 3.70 0.729 0.107 27 12/15/62 2:00 0.149 15 3.44 0.709 0 .111 23 12/31/63 23: 00 0.144 16 3.22 0.690 0.087 40 12/21/64 4:00 0.139 17 3.03 0.670 0 .103 35 1/05/66 16:00 0.137 18 2.85 0.650 0.166 11 1/19/67 14:00 0 .116 19 2.70 0.630 0.116 19 8/24/68 16:00 0 .112 20 2.56 0.610 0.103 36 12/03/68 16:00 0 .112 21 2.44 0. 5 90 0.104 33 1/13/70 23:00 0.112 22 2.32 0.570 0.105 32 12/06/70 8:00 0 .111 23 2.22 0.550 0.208 6 2/27 /72 7:00 0.109 24 2.13 0.530 0.092 39 1/13/73 2:00 0 .108 25 2.04 0.510 0.106 29 11/28/73 9:00 0.107 26 1. 96 0. 4 90 0 .182 9 12/26/74 23:00 0 .107 27 1. 89 0.470 0.106 30 12/02/75 20:00 0.106 28 1. 82 0. 450 0.061 47 8/26/77 2:00 0.106 29 1.75 0. 430 0.106 28 9/22/78 19:00 0.106 30 1. 70 0.410 0.065 46 9/08/79 15:00 0.106 31 1. 64 0.390 0.137 18 12/14/79 21:00 0.105 32 1. 59 0.370 0 .108 25 11/21/80 11: 00 0.104 33 1. 54 0.350 0.218 5 10/06/81 15:00 0.103 34 1. 49 0.330 0 .112 21 1/05/83 8:00 0.103 35 1. 45 0.310 0.109 24 1/03/84 1:00 0.103 36 1.41 0.291 0.058 48 2/11/85 3:00 0.102 37 1. 37 0.271 0 .190 8 1/18/86 16:00 0.097 38 1. 33 0.251 0 .167 10 11/24/86 3:00 0. 092 39 1. 30 0.231 0.073 44 1/14/88 12:00 0.087 40 1.27 0.211 0.056 49 11/05/88 14:00 0.087 41 1.24 0 .191 0.307 1 1/09/90 6:00 0.078 42 1.21 0 .171 0. 265 3 11/24/90 8:00 0.078 43 1.18 0.151 0.102 37 1/27/92 17: 00 0.073 44 1.15 0.131 0 .078 42 3/22/93 22:00 0.068 45 1.12 0 .111 0.043 50 11/30/93 22:00 0.065 46 1.10 0.091 0.106 31 2/19/95 17:00 0.061 47 1. 08 0.071 0.222 4 2/08/96 10:00 0.058 48 1. 05 0.051 0.158 13 1/02/97 6:00 0.056 49 1. 03 0.031 0.112 22 10/04/97 15:00 0. 043 50 1. 01 0. 011 Computed Peaks 0.341 100.00 0.990 Computed Peaks 0.298 50.00 0.980 Computed Peaks 0.257 25.00 0. 960 Computed Peaks 0.206 10.00 0.900 Computed Peaks 0.196 8.00 0.875 Computed Peaks 0 .168 5.00 0.800 Computed Peaks 0.116 2. 00 0.500 Computed Peaks 0.084 1. 30 0.231 Flow Frequency Analysis LogPearson III Coefficients Time Series File:cb4a.tsf Mean= 0.641 StdDev-0 .148 Project Location;Sea-Tac Skew"" 0.477 B-77 SE J4(h Street-June 2007 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 4.78 21 2/16/49 21:00 10.01 1 89.50 0. 989 9.85 2 3/03/50 16:00 9.85 2 32.13 0. 969 5. 62 9 2/09/ 51 2:00 8.83 3 19.58 0.949 3. 3 9 39 1 /30/ 52 8:00 8.04 4 14.08 0. 929 3.11 44 3/24/53 15:00 6.85 5 10.99 0.909 4 .19 24 12/19/53 19:00 6. 76 6 9.01 0.889 4. 71 22 2/07/55 17: 00 6. 21 7 7.64 0.869 4.82 20 12/20/55 17: 00 6.01 8 6.63 0.849 5.41 12 12/09/56 14:00 5. 62 9 5.86 0.829 4 .19 25 12/25/57 16:00 5.52 10 5.24 0.809 3 .16 43 1/26/59 20:00 5.49 11 4.75 0.789 4. 92 18 11/20/59 21:00 5.41 12 4. 34 0.769 3.78 34 2/14/61 21:00 5.37 13 3.99 0. 74 9 3.20 42 11/22/61 2:00 5.35 14 3.70 0. 729 3.90 29 12/15/62 2:00 5.16 15 3.44 0.709 4 .13 26 12/31/63 23:00 4. 98 16 3.22 0.690 3.49 37 12/21/64 4:00 4. 92 17 3.03 0. 670 3. 7 9 33 1/05/66 16:00 4. 92 18 2.85 0.650 5. 4 9 11 11/13/66 19: 00 4.84 19 2.70 0.630 5.35 14 8/24/68 16:00 4.82 20 2.56 0.610 3. 62 36 12/03/68 16:00 4.78 21 2.44 0.590 3.85 32 1/13/70 22:00 4.71 22 2.32 0.570 3. 87 30 12/06/70 8:00 4.23 23 2.22 0.550 6.85 5 2/27/72 7:00 4.19 24 2 .13 0.530 3.34 41 1/13/73 2:00 4.19 25 2.04 0.510 4 .11 27 11/28/73 9:00 4.13 26 1.96 0.490 6.21 7 12/26/74 23:00 4 .11 27 1. 89 0.470 3.70 35 12/02/75 20:00 4.07 28 1. 82 0.450 3.05 45 8/26/77 2:00 3.90 29 1. 75 0.430 4. 92 17 9/22/78 19: 00 3.87 30 1. 70 0.410 3.38 40 9/08/79 15:00 3.86 31 1. 64 0.390 5 .16 15 12/14/79 21:00 3.85 32 1. 59 0. 370 4.84 19 11/21/80 11:00 3.79 33 1. 54 0. 350 8.04 4 10/06/81 15:00 3.78 34 1. 4 9 0.330 4.23 23 10/28/82 16:00 3.70 35 1. 45 0.310 4.07 28 1/03/84 1:00 3.62 36 1. 41 0 .291 2.75 46 6/06/85 22:00 3. 4 9 37 1. 37 0.271 6.01 8 1/18/86 16: 00 3.48 38 1. 33 0. 251 5.52 10 11/24/86 3:00 3.39 39 1. 30 0. 231 2.57 48 1/14/88 12:00 3.38 40 1.27 0 .211 2.63 47 11/05/88 14:00 3.34 41 1.24 0 .191 10.01 1 1/09/90 6:00 3.20 42 1. 21 0.171 8.83 3 11/24/90 8:00 3.16 43 1.18 0.151 3.86 31 1/27 /92 15:00 3 .11 44 1.15 0.131 2.55 49 3/22/93 22:00 3.05 45 1.12 0 .111 2.19 50 11/30/93 22:00 2.75 46 1.10 0. 091 3.48 38 11/30/94 4:00 2. 63 47 1. 08 0.071 6.76 6 2/08/96 10:00 2.57 48 1. 05 0.051 5.37 13 1/02/97 6:00 2.55 49 1. 03 0.031 4. 98 16 10/04/97 15:00 2 .19 50 1. 01 0. 011 Computed Peaks 10.86 100.00 0. 990 Computed Peaks 9.57 50.00 0.980 Computed Peaks 8.36 25.00 0. 960 Computed Peaks 6.86 10.00 0. 900 Computed Peaks 6.57 8. 00 0.875 Computed Peaks 5. 7 6 5.00 0.800 B-78 SE 14¢1' Street-June 2007 Computed Peaks 4.25 2.00 0.500 Computed Peaks 3.35 1. 30 0. 231 Flow Frequency Analysis LogPearson III Coefficients Tirne Series File:cbl8a.tsf Mean= 1.006 StdDev~ 0 .144 Project Location:Sea-Tac Skew~ 0.500 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Tirne of Peak --Peaks Rank Return Prob {CFS) {CFS) Period 11.14 18 2/16/49 21 :00 22.43 1 89.50 0. 989 21. 83 2 3/03/50 16:00 21. 83 2 32.13 O. 969 14.72 7 2/09/51 15:00 19.81 3 19.58 0. 94 9 8.02 38 1/30/52 8: 00 18.28 4 14.08 0. 929 7.15 45 3/24/53 15:00 16.05 5 10.99 0.909 9.63 23 12/19/53 19:00 15.54 6 9.01 0.889 11. 00 19 2/07/55 17:00 14.72 7 7.64 0.869 11.33 17 12/20/55 17:00 14.05 8 6.63 0. 84 9 12. 33 14 12/09/56 14:00 13.90 9 5.86 0.829 9. 52 25 12/25/57 16:00 13.36 10 5.24 0. 809 7.42 42 1/26/59 20:00 12.80 11 4.75 0. 7 8 9 12.72 12 11/20/59 21:00 12. 72 12 4.34 0. 769 8. 7 6 34 2/14/61 21: 00 12.37 13 3.99 0. 74 9 7.24 43 11/22/61 2:00 12.33 14 3.70 0. 729 8.93 30 12/15/62 2:00 11. 96 15 3.44 0. 709 9.51 26 12/31/63 23:00 11. 67 16 3.22 0.690 8.01 39 12/21/64 4:00 11. 33 17 3.03 0.670 8. 8 6 32 1/05/66 16:00 11.14 18 2.85 0.650 12.37 13 1/19/67 14:00 11. 00 19 2.70 0.630 11. 96 15 8/24/68 16:00 10. 83 20 2.56 0.610 8.55 36 12/03/68 16:00 10. 75 21 2.44 0. 590 8.89 31 1/13/70 22:00 10.65 22 2.32 0.570 9.00 29 12/06/70 8: 00 9.63 23 2.22 0.550 15. 54 6 2/2"1/72 7: 00 9.57 24 2.13 0.530 7.85 41 1/13/73 2:00 9.52 25 2.04 0.510 9 .13 28 11/28/73 9:00 9.51 26 1. 96 0. 4 90 14.05 8 12/26/74 23:00 9.24 27 1. 89 0. 470 8. 70 35 12/02/75 20:00 9.13 28 1.82 0. 450 7.23 44 8/26/77 2:00 9.00 29 1. 75 0.430 10.83 20 9/22/78 19:00 8.93 30 1. 70 0.410 7.86 40 9/08/79 15:00 8.89 31 1. 64 0.390 11. 67 16 12/14/79 21:00 8.86 32 1. 59 0.370 10.65 22 11/21/80 11: 00 8.84 33 1. 54 0.350 18.28 4 10/06/81 15:00 8. 76 34 1. 49 0.330 9. 57 24 10/28/82 16:00 8.70 35 1.45 0.310 9.24 27 1/03/84 1:00 8.55 36 1. 41 0 .291 6.55 46 6/06/85 22:00 8.31 37 1.37 0. 271 13. 90 9 1/18/86 16:00 8.02 38 1. 33 0.251 13.36 10 11/24/86 4:00 8.01 39 1. 30 0.231 6.18 48 1/14/88 12:00 7.86 40 1.27 0.211 6.12 49 11/05/88 14:00 7.85 41 1. 24 0.191 22 .43 1 1/09/90 6:00 7.42 42 1.21 0 .171 19.81 3 11/24/90 8:00 7.24 43 1. 18 0.151 8.84 33 1/27/92 15:00 7.23 44 1.15 0.131 6.20 47 3/22/93 22:00 7.15 45 1.12 0 .111 5 .26 50 11/30/93 22:00 6.55 46 1.10 0.091 8.31 37 12/27/94 1:00 6.20 47 1. 08 0. 071 16.05 5 2/08/96 10:00 6.18 48 1. 05 0.051 12.80 11 1/02/97 6:00 6.12 49 1. 03 0.031 10.75 21 10/04/97 15:00 5. 26 50 1. 01 0. 011 8-79 SE J 44"' Street-June 2007 Computed Peaks 24.66 100.00 0.990 Computed Peaks 21. 78 50.00 0.980 Computed Peaks 19.08 25.00 0.960 Computed Peaks 15.70 10. 00 0.900 Computed Peaks 15.05 8.00 0.875 Computed Peaks 13. 24 5.00 0. 800 Computed Peaks 9. 8 6 2.00 0.500 Computed Peaks 7.83 1.30 a. 231 B-80 SE 144'1' S1reet-June 2007 Appendix C. XP-SWMM Model Results SE I 44'n Streer-June 2007 Table C.1. XP-Storm Conveyance Reach Descriptions Upstream Upstream Invert Downstream Link Node Downstream Elevation Invert Diameter Name Name Node Name Length ft Roughness ft Elevation ft Shape (Height) ft P01 CB1 DS 200.00 0.02 355.41 335.00 Circular 2.00 P02 CB2 CB1 200.00 0.02 359.42 357.41 Circular 2.00 P04 CB3 CB2 220.00 0.02 361.55 359.52 Circular 2.00 PD6 CB4 CB3 210.00 0.02 363.83 361.60 Circular 2.00 P10 CBS CB4 42.00 0.02 363.88 363.98 Circular 2.00 P12 CB6 CB5 44.00 0.02 364.11 364.13 Circular 2.00 P14 CB7 CB6 150.30 0.02 364.93 364.31 Circular 1.50 P16 CB8 C87 169.30 0.02 365.45 364.99 Circular 1.50 P19 CB9A CB9 50.00 O.Q1 366.73 366.33 Circular 1.00 P18 CB9 CBS 168.30 0.02 365.93 365.50 Circular 1.50 P20 CB10 CB9 182.40 0.02 366.45 365.98 Circular 1.50 P21 C810A C810 39.00 0.02 367.11 366.92 Circular 1.00 P22 C811 C810 141.60 0.02 366.95 366.48 Circular 1.50 P70 CB11A CB11 34.00 0.02 367.63 367.49 Circular 1.00 MU11A CB11A CB10A 120.00 0.01 370.48 370.24 Trapezoidc 0.30 MU11B CB11B CB11A 160.00 0.01 370.50 370.38 Trapezoidc 0.40 MU118 CB118 CB11A 160.00 0.01 370.60 370.48 Trapezoid.; 0.30 P24 CB12 CB11 169.30 0.02 367.52 367.00 Circular 1.50 P26 CB13 CB12 142.40 0.02 367.85 367.52 Circular 1.50 P50 CB14A CB14 52.00 0.01 369.46 369.25 Circular 1.00 ST14A CB14A CB118 260.00 0.01 371.39 370.70 Trapezoid::: 0.20 P28 CB14 C813 115.00 0.02 368.15 367.92 Circular 1.50 P30 CB15 CB14 34.00 0.02 368.42 368.20 Circular 1.50 P60 C815A C815 52.00 0.01 369.19 368.87 Circular 1.00 OV15A CB15A CB14A 38.00 0.01 371.41 371.39 Trapezoidc 0.20 P54 CB14C CB14B 105.00 0.01 370.25 369.89 Circular 1.00 P64 CB15C CB15B 105.00 0.01 373.17 371.37 Circular 1.00 P66 CB15D CB15C 60.00 0.01 379.23 373.30 Circular 1.00 P32 CB16 CB15 197.40 0.02 369.15 368.52 Circular 1.50 P34 CB17 CB16 300.50 0.02 371.76 370.27 Circular 1.50 P36 CB18 CB17 118.30 0.02 372.98 372.41 Circular 1.50 P37 CB18A CB18 37.00 0.02 373.91 374.13 Circular 1.50 D1 CB18A N15A-2 10.00 0.03 375.50 375.40 Trapezoidc 0.50 P38 CB19 CB18 198.50 0.02 374.69 373.83 Circular 1.00 P40 CB20 CB19 247.50 0.02 375.98 374.74 Circular 1.00 P42 CB21 CB20 192.20 0.02 376.95 375.98 Circular 1.00 P08 CB4A C84 190.00 0.02 366.18 364.73 Circular 1.50 P52 C8148 C814A 28.00 0.01 369.89 369.49 Circular 1.00 P62 CB15B CB15A 142.00 0.01 371.32 369.39 Circular 1.00 P61 CB15A-1 CB15A 20.00 O.Q1 370.20 369.27 Circular 1.00 P61 CB15A-1 CB15A 20.00 0.01 372.03 371.31 Trapezoidc 0.30 POSA CB4B CB4A 190.00 0.02 367.26 366.18 Circular 1.50 POSS CB4C CB4B 25.00 0.02 367.63 367.26 Circular 1.50 D2 N15A-2 CB15A-1 590.00 0.03 376.00 370.20 Natural 2.00 Table C.2. XP-Storm Inflows -25-Year Peak Rates Node Name Constant Inflow ft"3/s CB1 CB2 CB3 0.045 CB4 0.206 CBS CB6 0.242 CB7 CB8 0.198 CB9A 0.297 CB9 CB10 CB10A CB11 0.126 CB11A CB11B CB12 CB13 CB14A CB14 0.200 CB15 0.588 CB15A 0.724 CB14C 0.388 CB15C CB15D C816 CB17 CB18 0.204 CB18A 19.080 GB19 CB20 CB21 0.157 CB4A CB14B CB158 DS CB15A-1 CB4B CB4C 8.360 N15A-2 Table C.3. XP-Storm 25-Year Water Surface Elevations Ground Max Elevation Water Node (Spill Elevation Freeboard Name Name Crest) ft (ft) (ft) CB1 CB1 362.33 356.168 6.16 CB2 CB2 363.47 361.096 2.37 CB3 CB3 365.3 363.217 2.08 CB4 CB4 368.98 365.394 3.59 CBS CBS 369.38 365.546 3.83 CB6 CB6 368.31 365.711 2.6 CB7 CB7 368.87 366.833 2.04 CBS CB8 369.4 368.097 1.3 CB9A CB9A 369.78 369.244 0.54 CB9 CB9 370.08 369.242 0.84 CB10 CB10 370.57 370.303 0.27 CB10A CB10A 370.54 370.54 0 CB11 CB11 370.85 370.689 0.16 CB11A CB11A 370.78 370.69 0.09 CB11B CB11B 370.9 370.751 0.15 CB12 CB12 371.3 371.084 0.22 CB13 CB13 371.97 371.42 0.55 CB14A CB14A 371.59 371.59 0 CB14 CB14 372.3 371.691 0.61 CB15 CB15 372.37 371.914 0.46 CB15A CB15A 371.61 371.61 0 CB14C CB14C 373.43 371.615 1.81 CB15C CB15C 376.36 373.17 3.19 CB15D CB15D 382.03 379.23 2.8 CB16 CB16 374.35 373.612 0.74 CB17 CB17 378.16 376.102 2.06 CB18 CB18 378.63 377.195 1.44 CB18A CB18A 378.66 377.601 1.06 CB19 CB19 379.29 377.209 2.08 CB20 CB20 379.8 377.226 2.57 CB21 CB21 380.47 377.315 3.16 CB4A CB4A 373.58 368.27 5.31 CB148 CB14B 372.27 371.598 0.67 CB15B CB15B 374.02 371.611 2.41 OS OS 340 337 3 CB15A-1 CB15A-1 372.33 372.33 0 CB4B CB4B 371.36 370.179 1.18 CB4C CB4C 370.43 370.43 0 N15A-2 N15A-2 378 377.519 0.48 Table C.4. XP-Stonn 25-Year Flow Rates Max Max Velocity Invert Water Max Flow (ft/s, mis) Node Elevation Elevation Link Name cfs ft/s Name fl ft P01 10.86 10.01 CB1 355.41 356.17 P02 10.86 3.99 CB2 359.42 361.10 P04 10.87 3.91 CB3 361.55 363.22 P06 10.90 4.12 CB4 363.83 365.39 P10 4.89 1.78 CBS 363.88 365.55 P12 4.90 1.84 CB6 364. 11 365.71 P14 4.63 2.62 CB7 364.93 366.83 P16 4.63 2.60 CBS 365.45 368.10 P19 0.30 0.38 CB9A 366.73 369.24 P18 4.42 2.49 CB9 365.93 369.24 P20 4.13 2.31 CB10 366.45 370.30 P21 1.33 1.67 CB10A 367.11 370.54 P22 2.80 1.57 CB11 366.95 370.69 P70 0.12 0.15 CB11A 367.56 370.69 MU11A 2.66 1.33 CB11A 367.56 370.69 MU11B 1.96 0.82 CB11B 369.40 370.75 MU11B 0.80 0.58 CB11B 369.40 370.75 P24 2.57 1.44 CB12 367.52 371.08 P26 2.57 1.44 CB13 367.85 371.42 P50 (1.19) (1.50) CB14A 369.46 371.59 ST14A 2.76 1.57 CB14A 369.46 371.59 P28 2.57 1.44 CB14 368.15 371.69 P30 3.56 2.00 CB15 368.42 371.91 P60 (2.07) (2.60) CB15A 369.19 371.61 OV15A 1.40 0.78 CB15A 369.19 371.61 P54 0.39 0.49 CB14C 370.25 371.62 P32 5.04 2.82 CB16 369.15 373.61 P34 5.04 2.82 CB17 371.76 376.10 P36 5.04 2.82 CB18 372.93 377.20 P37 5.13 2.88 CB18A 373.91 377.60 D1 14.66 3.09 CB18A 373.91 377.60 P38 (0.37) 0.20 CB19 374.69 377.21 P40 (0.32) 0.26 CB20 374.72 377.23 P42 0.16 0.87 CB21 375.98 377.32 P08 5.73 3.35 CB4A 366.18 368.27 P52 0.39 0.49 CB148 369.89 371.60 P61 3.78 4.78 CB15A-1 370.20 372.33 P61 2.55 5.62 CB15A-1 370.20 372.33 POSA 5.73 3.22 CB4B 367.26 370.18 P08B 5.73 3.23 CB4C 367.63 370.43 D2 14.66 8.62 N15A-2 375.00 377.52 i i ~ .... e I iS ; ~ " = = " § ,a =' ,..; u e = .!!,I> "" I I ! ! ·r----- i ·-I ----+-·- I i ----+- • •• jJ. ~~-.:,j . ! "'H " .. i=.. E .. .. " ~ Ill .... I Ill .... I = u i = ... .,. = u I " a e = .. i=.. " -:= = .. i .. .,, :,, = ,-; c.l " .. = Cl) -~ ~ . -!---- \ l; i s ~ ' i I • s i .. I I I t-----a~ ' ' "' .. e I • ,, ,. "' •· ---;; ,r-1-- . ' I I -1-------- • I I I -· ;~i ij~o l ~----"11 ..........i= ___ __J:~r Appendix D. HEC-RAS Analysis of Roadway Conveyance Description of inputs: Geometry: Geometry of roadway based on Barghausen Consulting Engineers field survey from 6/07. STA Description 0+00 10' west of CB-11A 1+60 10'west of CB-11B 6+60 160' east of CB-15A-1 8+10 290' west of CB-18A 1010 85' west of CB-18A Based on cumulative 100-year peak flow rate to the conveyance system predicted by KCRTS 1- hour time series minus the estimated capacity of the 18-inch pipe on the south side of SE 144th Street (5.0 cfs). SE 14.fh Streel -June 2007 SE 144th Roadway Conveyance Plan: SE144th Roadway 6/17/2007 Geom: SE144th Flow: Roadway a 380 144th 1 , Legend WS Exis Ground ROB 378 376 g ~ ,g ~ " iii 374 372 0 ljS 0 + "' + + 0 -"' "' -.!!I 13 .!!I 13 en en 370 0 200 400 600 800 1000 1200 Main Channel Distance (ft} "'. ,., "' E I "" "' 378 377 "' .30 378.0 ' an.s Jn.O E I 378.5 Ill 376.0 375.5 375.0 374.5 "" 375.5 375. 374.5 £ 374.0 i 373.5 373.0 372.5 372.0 371.5 -30 SE 144th Roadway Conveyance Plan: SE1441h Roadway 6/17/2007 Gaom: SE1«1h Flow: ROlldwaY Q Rlvflra:1«1h Reech=1 RSm1010 Sta10+10 ·'" ----~..-------------------------,01 .035-------,, .,. ·10 10 " Statloo (fl! SE 144th Roadway Conveyance Plan: SE 144th Roadway 6/17/2007 Geom: SE1«th Flow: RoaaMly Q Rlver=1441h Reacf1=1 RS .. 810 Sta8+10 "' ___ _,,,~----------------.01 .ltl5---------- .,o .,a ·= "" .,o 10 Statlcrn (ft) " SE 144th Roadway Conveyance Plan: SE144th Roadway 6/1712007 Geom, S£1"4th Flow. Ro&dw>fy a River" 1441h Reach .. 1 RS,. 660 Sia 6'-60 30 " "' -----------------.... ----------035----------- a " " 30 " Sta~on (") 30 wsem G=od • Bank Sta r.g.nd . WS Exls I--;;;;;;;- " • Bank Sta ~ • I G~ I ~ '' 374.5--, I---·'" 374.0 373.5 € 373., I 372.5 372.0 371.5 371.0 370.5 . ., 372.5· 372.0 371.5 g J 371.0 370.5 370.0 369.5 369.D ..., SE 1441h Roadway Coriveyance Plan: SE144th Roadway 6/17/2007 Geom: SE1441h Flow; Roadway a Rlverz 1441h Raeeh" 1 RS ,.180 s .. 1->(;0 -i~--------------.01 022--------4 -20 ·10 c::--------------~----~ "' 20 " " 10 sta~an (ft) SE 144th Roadway Conveyance Plan: SE144U, Roadway 6/17/2007 G!!,om: SE144th Flow: Roedwey a RMlr " 1441h Reech " t RS ,. 0 Sta 0+00 ·"' 01 .022,------,i ~, .,o 20 "' " station (fl) ..... ws "'' ~ • BonkSlo '""""" wse,;, -~ • ....... ~ ~ .. HEC-RAS Plan: SE144th River: 144th Reach: 1 Profile: Exis ~ Reach River Sta Profile QTotal Min Ch El W.S. Elev . CritW.S. E.G. Elev E.G. Slope Val Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/tt) (ft/s) (sq tt) ' (ft) 1 1010 Exis 20.09 378.07 378.44 378.22 378.56 0.005394 2.69 7.44 20.08 1.35 . 1 810 Exis 20.09 376,47 376.22 376.22 376.57 0.023460 4.23 6.22 0.00 1 660 Exls 20.09 373.69 373.70 373.33 373.84 0.006877 0.31 6.62 7-79 0.86 . 370.901 28.69i 1. 12 1 160 Exis 22.42 371.63 371.63 371.77 0.002867 3.25 7.92 1 0 Exis 22.42 370.701 371.16 371.14 371.27 0.003401 3.00 9.76 44.46 1.m - ! " Ee.! iVlcCarthy P.E., P.S. S195 7 :l 7:l ',( ,'\·Jenue SE Henton. ·vv.A ]8U59 f'c-d Ul'.2~)l '111_.-5734 F(1:-,; {42~)} 271-343:2 . ' ·\ p; -';i" ... P.O. BOX 1255 F\LE cog}sEYENGINEERING FALL CITY, WA 98024-1255 CELL: 206-227-8187 FAX: 425-228-7232 November 20, 2003 Bruce Whittaker, P.E. L.U.S.D. King County D.D.E.S. REFERENCE: Liberty Grove Contiguous, L03P0005, (L03TY401) and Liberty Grove, L03P0006, (L03TY403) SUBJECT: Response to November 12, 2004, Plat Screening, Request For Additional Downstream Information Dear Mr. Whittaker: The following is a narrative of the existing downstream system from the Parcel "B" portion of the Liberty site to the Petrie Property. A. Description of stormwater drainage within the Parcel "B" portion of project: The stormwater generated from the site in the existing condition and any stormwater that enters the site from the north (SE 136th St.) flows to an existing wetland at the southern central portion of the property. The wetland is shown on the preliminary plat. Stormwater leaves Parcel "B" at the low point of the wetland and flows to the south. It should be noted that the wetland is not a closed depression. B. Description of Stormwater Drainage Across Property#l: Tax Parcel#: "0095" 13802 1601h Ave. SE Steve & Joanne Lee This property is located directly to the south of Parcel "B" of the proposed development. Permission was granted by the property owner to cross this property. Stormwater leaving Parcel "B" (under a wood fence) enters Property#l and is intercepted by a constructed swale (sump). See Picture#2 that is taken from the STORMWATER HYDRAULIC ANALYSIS CIVIL ENGINEERING DESIGN RECEIVED NOV 2 5 2003 KING COUNTY LAND PLANNING /1,fJJ.IN /:t. LAND USE SERVICES 'I.I: Cop,, ' North end of the swale looking south. The swale (sump) is approximately 15' wide and 28' long. At the south end of the swale there is a 12" Concrete Pipe (CP). The top of the existing grade around the swale is approximately 3.5' above the IE of the culvert. The culvert conveys stormwater across this property to the adjacent property to the south. Within this property there is also an additional swale that flows into the above mentioned sump. The swale is to the south of the Parcel "B" fence and begins approximately 50' east of the southeast corner Parcel "B". This swale intercepts stormwater leaving the Parcel "B" property and directs the stormwater to the west to the sump feature. Picture #1 is taken to the east of the sump, looking to the east. This swale is approximately 10' wide and 2' deep with gentle side slopes. The swale is grassed and is stable. C. Description of Stormwater Drainage Across Property#2: Tax Parcel#: "0096": 13814 160th Ave. SE Brett Bowden. Mr. Bowden granted permission to cross his property. Reach 1: A 12" CP conveyance system outfalls from Property 1 to Property 2 adjacent to a large cottonwood stump. The pipe discharges into a short swale/ditch that is approximately 8' long and 3' wide. The swale is approximately 3' deep with varying side slopes and appears to be stable. At the end of the swale is a 12" CP pipe that conveys stormwater under a gravel road. The IE of the CP to the top pf the gravel road is approximately 2.5'. Reach 2: Stormwater leaves the 12" CP under the gravel road and enters a broad swale. Picture#3 was taken near the upstream culvert under the gravel road looking to the south. The swale is approximately 110' long, 3' wide at the bottom, approximately 3' deep with varying side slopes. The swale ends at another gravel road. There is a 12" CP at the southern end of the swale where the water is conveyed under the gravel road. Picture #4 was taken at the southern end of Reach 2 looking to the north. D. Description of Stormwater Drainage Across Property#3: Tax Parcel# "0101": The property owner was not home and a card was left at the front door. Reach 1: Stormwater leaving the 12" CP under the gravel road from Property 2, discharges into a shallow ditch on the north side of the driveway access to the Property 3 residence -see Picture #5. The ditch flows for a short distance to the south and then turns to the west -see Picture #6. At the western terminus of the ditch, stormwater is intercepted by a 12" CP that conveys stormwater under the driveway to the south .. Picture #7 shows the outfall at the southern side of the gravel drive. The ditch is approximately 2' wide, l' deep with varying side slopes. There was approximately 2' from invert to the top of the gravel road. There were no observed capacity issues within this reach. FILE COP'f P 0. BOX 1255 FALL CITY, WA 98024-1255 CELL: 206-227-8187 FAX: 425-228-7232 CASEY ENGINEERINefCE!VED , November 20, 2003 Karen Scharer, Planner L.U.S.D. King County D.D.E.S. NOV 2 5 2003 KING COUNTY LAND USE SERVICES L03P0005 REFERENCE: Liberty Grove Contiguous, L03P0005, (L03TY401) and Liberty Grove, L03P0006, (L03TY403) SUBJECT: Dear Ms, Scharer: Response to November 12, 2004, Plat Screening, Request For Additional Information On behalf ofLakeridge Development, Inc.,the following is a response to the November 12, 2003 letter. 1. Property Description, Engineering & Surveying: Attached are three copies ofan attached "Waste Disposal Drain Field Easement" that is the only known easement that has not been disclosed at this time. This easement will be relinquished at the time the project is recorded. 2. Drainage: Attached to this letter are 10 copies of the requested additional downstream information. It is proposed that the combined water quality facility within the project be designed to provide for hydrology to the existing on-site wetland and the existing downstream system. 3. Rezone(s): The Applicant respectfully requests that the rezone application be withdrawn. This request for the withdrawal of the rezone application was made clear in the August 6, 2003 letter from Lakeridge Development to Karen Sharer. Attached is a copy of the letter that has been already submitted to King County D.D.E.S. STORMWATER HYDRAUIJC ANALYSIS CIVIL ENGINEERING DESIGN LAND PLANNING Karen Scharer November 20, 2003 Page 2. Lakeridge Development, Inc. greatly desires to schedule a hearing date at your earliest convince. Thank-you for your consideration. If you have any questions, please feel free to contact me at any time. Sincerely; 5-f)~ 1v.7 David W. Casey, P.E. Casey Engineering Attachments: I. 3-Copies of"Waste Disposal Drainfield Easement" Document. 2. I-Copy of"Plat Screening Transmittal" Document. 3. !-Copy of August 6, 2003 Letter From Lakeridge Development, Inc. to Karen Scharer -previously submitted. 4. I 0-Copies of Requested Additional Downstream Information. Cc: Bruce Whittaker, P.E., King County LUSD,DDES ® Plat Screening Transmittal King County Preliminary Plat App's: Liberty Grove Contiguous, and Liberty Grove Oepartmeru of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, Washington 9805.5-1219 LUSD File No. L03P0005 (L03TY401), L03P0006(L03TY403) Date of Information Request: November 12, 2003 Deadline for Submittal of Information: February 12, 2004 1. Property Description, Engineering & Surveying: a. The title report discloses several easements affecting the property. Many of these were not included with the title report and need to be reviewed prior to preliminary approval. Some may need to be relinquished. Submit easement documents for LGC so that review of their impacts may be completed. 2. Drainage: Please respond to comment 4b of the previous screening letter dated June 3, 2003 which states:. b. Revise the Level 1 Off Site Analysis to include evaluation of the existing downstream drainage course from the Liberty Grove Contiguous site. It appears that the existing drainage course flows to the east of known capacity problems on Lot 6, Block 3 of Cedar Park Five-Acre Tracts (downstream points 30 and 31 in the Analysis). Please show appropriate mitigation for routing the post developed drainage through this area per Core Requirement 2 of the KCSWDM. Note that the Level 1 Analysis can be extended more than Y. mile if a problem is anticipated (1.2.2.1 KCSWDM). It is anticipated that up sizing the existing culverts east of 160the Ave. SE will be required. A letter of positive intent from the property owner(s) is required for any proposed improvements off the R/W. A full description and Level 1 Analysis of the existing drainage course is required. The existing drainage course should be evaluated so that all options for the proposed surface water adjustment can be fully explored. It is still anticipated that up-sizing the existing culverts across Lot 6, Block 3 of Cedar Park Five-Acre Tracts will be required. Please note that the applicant for the proposed Nichols Place L03P0015 subdivision is also evaluating the feasibility of up-sizing the culverts. We suggest that coordinating this effort may be beneficial to both applicants. Please contact Bruce Whittaker at 206-296- 7211 for further information The proposed surface water adjustment has been placed on hold pending receipt of the above information. Please contact Mark Bergam at 206-296-7270 for more information on the proposed adustment. Please provide ten ( 10) copies. L03P0005 & L03P0006 2°' Plat Screening Transmittal 11/12/03 Page 2 3. Rezone(s): Please clarify whether you wish to withdraw applications for reclassification or if you wish to continue processing the rezone requests. 2 L03P0005 & L03PD006 Plat Screening Transmittal Page 3 e. Perform a travel time analysis to compare an actual morning peak hour travel time along the 1601h Avenue to SE 144th Street to SE 156'" Street trip versus a theoretical SE 136'" Street to 1561" Avenue SE, with appropriate delays factored into the westbound left turn to proceed southbound on 156 1h Avenue SE. The newly constructed west leg of SE 1361h Avenue SE may serve as a reasonably accurate source of data on the delays required to complete a left turn across 156'" Avenue SE. Other single lane approach "STOP" controlled intersections along the portion of 1561" Avenue SE, between SE 1281h and SE 142°• Place. f. Updated traffic accident history (that is, include 2002). For more detailed information regarding the traffic study, please contact Kris Langley, Senior Engineer, Traffic & Engineering, KCDOT at (206) 263-6102 or (206) 296-7155 (or kristen.langley@metrokc.gov. Please provide ten (10) copies. 6. Road Variances: a. Please submit variances to the KCRS as necessary. b. Intersection spacing: plat entrance (LG) at 1601" Avenue SE (measured relative to the intersection of SE 1351"/160th Avenue SE) does not appear to meet King County Road Standards for a Neighborhood Collector street. 7. Road Improvements: a. Please provide a conceptual frontage improvement plan for LGC that includes (under a rezone scenario) an improvement of the frontage of the three intervening parcels (0086, 0087, 0088) that appear to have been segregated via a plat KING CO ENGINEER SUBDIVISION NO 6846 REC NO 9410250673 from the Tax Lot 0085 (the northerly portion of LGC). b. Please provide a conceptual frontage improvement plan for LG that includes the referenced improvements to SE 1361" Street to complete the improvements that are required of the Applicant of the Evendell subdivision (ODES File L01 P0016) under both the proposed (and subsequently denied) rezone configuration and the approved 46-lot (current zoning). c. If the Applicant for the plat of Evende!I does not succeed in the requested appeal to the County Council, the off-site connection of SE 136'h Street will not be constructed. This requirement may be placed upon this application as potential mitigation of plats' impacts at the intersection of SE 1281h Street/ 1601h Avenue SE. Please provide a conceptual plan for the improvement of SE 1361h Street between 1581~ Avenue SE and 1561h Avenue SE, including a sidewalk on (at least) the north side of the roadway, and a conceptual plan for the re- channelization of 156'" Avenue SE at SE 136'" Street. s; Pedestrian Connectivity/School Walkways: a. Information has been provided in the past that school age pedestrians have a gate available for access to the west side of the Liberty High School. Identify the walking routes from both LGC and LG to the location of the gate. Identify the conditions along the route. Where abutting the boundary of the LGC and LG plats, and, if not otherwise required, provide frontage and off-frontage improvements to accommodate this pedestrian activity. L03P0005 & L03P0006 Plat Screening Transmittal Page 4 b. Provide an analysis of walkway access to schools serving the two plats of Liberty Grove & Liberty Grove Contiguous (Liberty High School, Maywood Middle School, and Briarwood Elementary). See the attached comments from the Issaquah School District. 9. Wetland/Stream: A site visit was made to verify the wetland areas on Friday May 30, 2003. Based on this field visit the following additional information in regards to wetlands. There is an off-site wetland located north of SE 136'" Street and east of 162"' SE. Flows from this wetland enter the site in the northeast corner·of the property and flow south along the eastern edge of the site, in the area of proposed lots 9 -16. It appears that the water ponds in the area of proposed lots 17 -20. The applicant's biologist should evaluate these areas for wetlands. The submitted wetland report does not address these areas of concern. 10. Revised Preliminary Plat(s): Provide 15 copies of each revised preliminary plat, as necessary, as a result of above-referenced requests for additional information and 4 copies of any special study requested for each plat unless otherwise noted. As a result of the review of the information, additional information (studies, revisions, etc.) may be requested at a later date. Further evaluation of these issues may result in the reconfiguration and/or loss of lots. 11. Rezone(s): Based on the information submitted, DOES staff finds insufficient justification to recommend reclassification of either rezone request, see Comprehensive Plan Policy U-122. You may choose to submit further information, which addresses this policy as it applies to each site. Please provide two copies for each rezone file. 4 REVISED 09/03/03 Purpose of Checklist: The State Environmental Policy Act (SEPA), chapter 43.21 C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help King County and/ or any other agencies with jurisdiction to identify impacts from a proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help King County decide whether an EIS is required. A. BACKGROUND 1. Name of proposed project, if applicable: Liberty Grove Contiguous Subdivision 2. Name of proponent: REVISIO Lakeridge Development, Inc. 3. Address and phone number of proponent and contact person: Proponent: Contact Person: 4. Date checklist prepared: February 28, 2003 5. Agency requesting checklist: King County, DOES Lakeridge Development, Inc. PO BOX.146 Renton, WA 98057 (425) 228-9750 Phone Mel Daley or Hans Korve DMP Engineering 726 Auburn Way North (253) 333-2200 Phone (253) 333-2206 Fax REVISED 09/03/03 6. Proposed timing or schedule (including phasing, if applicable): Application Submittal ............................ March 2003 Public Hearing ........................................ December 2003 Council Action ........................................ February 2004 Engineering Submittal .......................... April 2004 Site Grading ........................................... May 2004 Final Plat ................................................. December 2004 L0SP00o5 RECEIVE. SEP O 3 2003 h11~l:i COUNTY LAND USE SERVIC S FOR AGENCY USE ONLY I LGC HAIN FILE COPY REVISED 09103/03 7. Do you have any plans for future additions, expansions, or further activity related to or connected with this proposal? If yes please explain. No. 8. List any information you know about that has been prepared, or will be prepared, directly related to this proposal. The following infonnation will be prepared and submitted under separate cover or is available in County files: • Rezone application -DOES • Level 1 Downstream Analysis REVISED July 11. 2003 • Conceptual Drainage Plan • Traffic Study. DN Traffic Consultants, February 7, 2003 • Wetland Report -Habitat Technologies, November 5, 2002 • Preliminary Recreation Plan • Traffic Study. DN Traffic Consultants. REVISED July 24. 2003 • Drainage Adjustment Request. July 11, 2003 • School Walking Route Analysis. August 18, 2003 • Addendum Wetland Report. H&S Consulting. July 18, 2003 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by this proposal? • Applicant has submitted a rezone application with this subdivision application. • Evendell Preliminary Plat approval (L01TY401) • Liberty Grove Preliminary Plat Approval 10. List any governmental approvals or permits that will be needed for your proposal, if known. SEPA Threshold Detennination Re-zone Approval Preliminary and Final Plat Approval Clearing and Grading Permits Building Pennits King County King County King County King County King County 11. Give brief. complete description of the proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. SUBDIVISION The proposed preliminary plat will subdivide two parcels, totaling 7.92 acres located on tax parcel(s) 145750 -0085 and 145750 -0090 into 36 single-family lots. open space, and access tracts. The property is located on the east side of 160"' Ave. SE (145750-0085 & 0090) and contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home and all the associated outbuildings are proposed for removal. This property is the second half of the original "Liberty Grove" project. All stonn water, traffic and recreational issues have been reviewed as one project but will be presented with each individual segment. 2 FOR AGENCY USE ONLY LGC REVISED 09/03/03 The associated re-zone application has been rejected by Staff and the applicant has submitted a TOR proposal to maintain the proposed density. Sewer service to the proposed project site will require extension of a 10" to 12" off-site sewer line from approximately 1541" Ave. SE to 162"" Ave. SE. within the existing SE 136'" Street right-of-way. Additional improvements may include a 1 O" sewer main in 162"" St. SE. and a 8" sewer main in 158 .. & 160'" Ave. SE REZONE This project and its contiguous neighbor, Liberty Grove have applied for a rezone from R-4 to R-6. This proposed rezone would be consistent with the current comprehensive plan designation. This proposal will also be consistent with the development patterns of the surrounding area. The plat of Evendell located west of the Liberty proposal is currently being rezones from R-4 to R-6 as well. Since the original application. Staff has withdrawn their support of the re-zone application. In response. the applicant has submitted documentation to utilize the Counties TDR program to attain the proposed lot density. No additional impacts will result form the use of the TDR program. 12. Location of the proposal. Provide a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if available. The subject proposal is situated on three parcels totaling 7.92 acres, located within the jurisdictional boundaries of unincorporated King County in the SE Y, of Section 14 Township 23 North, Range 5 East W.M. The site is located on parcel(s) 145750-0085 and -0090. Please refer to the Preliminary Plat map for the legal description, site plan, vicinity map, and topographic map. The proposed Plat of Liberty Grove is located to the north on the west side of 160'" Ave. SE. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one):! flat J. jrollingj, hilly, steep slopes, mountainous. The project site is located on the east side of 160'" Ave. SE. (-0085 & -0090) and contains a few minor slopes in the northeast corner of the property and a non-jurisdictional drainage channel which extends through the center of the property, from north to south. The northeastern portion of the site is classified as forested uplands. The remainder of the property is pasture with two existing homes and out buildings. One Class 3 wetland has been identified in the south-central portion of the site. The finding and classification has been reviewed and approved by DOES staff. Please refer to the preliminary plat map for detailed contour information. b. What is the steepest slope on the site (approximate percent slope)? According to the field topographic survey, the steepest slope on the site is approximately 5% to 10% located northeast corner of the project site. 3 FOR AGENCY USE ONLY LGC REVISED 09/03/03 c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, and muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. According to the US Soil Conservation Service Soil Map, the site is primarily Alderwood series (AgC) d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. According to the King County Sensitive Areas Map, the property contains no hazard areas. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. Grading of the site will be necessary to modify the site for stormwater drainage flow. The exact quantity of grading is not known at this time, however, it is anticipated that the grading activities would be designed to balance and not require import or export ·of soil. Grading of the individual home sites will involve the excavation of approximately 150 to 200 CY of cut and/or fill. These issues will be addressed during the building permit phase. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Some erosion could occur on-site as a result of construction activities; however, temporary erosion and sedimentation control measures to be approved by King County will be employed to reduce erosion impacts. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Due to the preliminary nature of the plans, the exact percentage of impervious surface associated with this project is currently unknown. The subject proposal will not exceed the maximum impervious surface area as required by KCC 21A.12.030 h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, the contractor will follow an approved temporary erosion and sedimentation control plan meeting KCC standards. Typical measures, which may be employed, include the use of silt fences, straw bales, and temporary storm drainage features. Hydro seeding exposed soils and cleared areas after construction will also reduce the potential for erosion. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. 4 FOR AGENCY USE ONLY LGC REVISED 09/03/03 2. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, and industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Construction: Emissions and dust particulates generated primarily by construction equipment will be produced during the construction phase of this project. The amount of emissions to the air will be minimal and will occur during the actual construction of the development. Long Tenn Air Quality: Long-term air impacts would be those typically associated with residential land uses. Sources of long-tenn emissions and odor could include vehicle emissions from increased vehicle use generated by the new residential units and emissions from wood burning fireplaces (if permitted). The additional vehicular emissions in these areas are not anticipated to concentrate and therefore are not anticipated to create a health hazard to the residents or surrounding areas. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No. c. Proposed measures to reduce or control emissions or other impacts to air, if any: If particulates become suspended during construction, frequent watering of the site during the construction phase of the project would be used to help control dust and other particulates generated on the site. This will be accomplished in accord with Section 5.4.7 of the 1998 Surface Water Design Manual. 3. Water a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. According to the King County Sensitive Areas "Folio, there are no recorded streams or other water bodies on the subject site. However, field investigation has revealed the presents of a single Class 3 wetland feature in the south-central section of the site. Habitat Technologies has 5 FOR AGENCY USE ONLY LGC ,:·.i _.·;:,::;. !_ibe:tyC.;rovc c.,J'ahJL:'.1L::; Pr0i:n-.1~a;y .=:1,:: i<:r19 C"'J!"lty .Si:PA <:)'.12ckLs' REVISED 09103/03 completed a full wetland assessment and report. The report was reviewed and approved by DOES Staff on November 27, 2002. 2) Will the project require any work over, in or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. The Class 3 Wetland, identified in the wetland report will be preserved and accorded the appropriate 25' buffers and 15' building setback. Grading and other construction activities are expected within 200' of the wetland feature but outside the required buffers. Appropriate measures will be taken to insure the integrity of the wetland feature during construction. Refer to the attached wetland report for complete details. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Creation of the proposed single-family lots will not require the adverse impact or placement of fill within identified wetland areas or buffers. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan According to the King County Sensitive Areas Maps, no portion of the site lies within the 100-foot flood plain. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No. b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. None known at this time. c. Water Runoff (including storm water): 6 FOR AGENCY USE ONLY LGC REVISED 09/03103 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. On-site storm water runoff will primarily be generated from roadways, residential structures, and associated driveways. Storm water will be collected in catch basins within the roadways and/or tight-lined from residential roof tops and conveyed to a proposed detention facility located on the project site (southwest comer of -0090). Storm water from the proposed plat of "Liberty Grove" will be transferred along 160"' Ave. SE and processed in the single storrnwater facility located on parcel -0090. Discharge from the proposed facility will be piped into the existing storm water system. Refer to the attached Level 1 storm water report for complete details. 2) Could waste materials enter ground or surface waters? If so, generally describe. Some pollutants normally associated with residential development could enter the surface water; however, the amount would be minimal since the on-site drainage will be conveyed to a water quality and detention facility in conformance with the 1998 Surface Water Design Manual. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: The storm water runoff will be collected and conveyed to a detention facility(s) that will be designed and constructed in conformance with the 1998 Surface Water Design Manual. 4. Plants a. Check or circle types of vegetation found on the site: deciduous tree: alder, maple, aspen, other: evergreen tree: fir, cedar, hemlock, pine, other shrubs grass pasture crop or grain wet soil plants: cattail, buttercup, bullrush, skunk cabbage water plants: water lily, eelgrass, milfoil, other: b. What kind and amount of vegetation will be removed or altered? The north portion of the project site, on the east side of 160'" Ave. SE, is currently covered with evergreen and deciduous trees with the remainder of the property in grasses and pasture land. There is some ornamental vegetation associated with the existing homes. The majority of existing vegetation will be removed during the grading process with the exception of buffer vegetation surrounding the retained wetland feature. All ornamental landscaping associated with the homes to be demolished will also be removed. See the attached wetland report for a complete list of existing vegetation. c. List threatened or endangered species known to be on or near the site. 7 FOR AGENCY USE ONLY LGC REVISED 09/03/03 There are no known threatened or endangered plant species on or near the site. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: The proposed preliminary plat anticipates retaining existing trees when possible. The new single-family residences will provide new landscaping including lawns, shrubs, and ornamental trees. Native vegetation will be utilized, where appropriate. Some additional trees and vegetation may be incorporated into the recreation area and storm water facility where appropriate. 5. Animals a. Circle any birds and animals, which have been observed on or near the site or are known to be on or near the site: birds: hawk, heron, eagle, songbirds, other: mammals: deer, bear, elk, beaver, other: rodents, raccoons. fish: bass, perch, salmon, trout, herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. None Known. c. Is the site part of a migration route? If so, explain. No. d. Proposed measures to preserve or enhance wildlife, if any: Retain native vegetation within the sensitive areas tract associated with the retained wetland feature. In addition. installation of native landscaping throughout the plat area will provide coverage and habitat for urban tolerant wildlife. Typical landscaping is likely to include rhododendron, azalea, boxwood, magnolia, cedar, hemlock, blue spruce, cherry, plum, maple and ash. Some additional landscaping will be installed in association with the proposed recreation facility. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electrical energy will be the primary source of power serving the needs of the project and natural gas will be made available for the purpose of heating and other needs associated with residential living. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No. 8 FOR AGENCY USE ONLY LGC REVISED 09103/03 c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: The residential buildings that will be constructed as a result of this project will meet or exceed the applicable single-family residential energy conservation / consumption requirements in King County and the Uniform Building Codes. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. It is unlikely under nonnal working conditions that environmental health hazards would be encountered. All project-related construction will meet or exceed current, County, State and Federal laws. 1) Describe special emergency services that might be required. In the event that environmental health hazards are encountered or occur during construction, all appropriate precautionary measures will be employed. Any emergency situation would be addressed by the existing resources of Fire District #25. 2) Proposed measures to reduce or control environmental health hazards, if any: State regulations regarding safety and the handling of hazardous materials will be followed during the construction process. Equipment refueling areas would be located in areas where a spill could be quickly contained and where the risk of hazardous materials entering surface water is minimized. On-site management will be equipped with mobile communications equipment at all times to contact emergency services in the event of an incident. b. Noise 1) What types of noise exist in the area, which may affect your project (for example: traffic, equipment operation, other)? The dominant source of noise in the project vicinity is traffic along 160th Ave. SE, which bisects the proposed project. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Short-term impacts would result from the use of construction equipment during site development. Construction would occur during permitted construction hours and in compliance with King County noise standards. 9 FOR AGENCY USE ONLY LGC REVISED 09/03/03 3) Proposed measures to reduce or control noise impacts, if any: Construction activity will be limited to pennitted construction hours and construction equipment will not be allowed to idle for continuous periods of time, which will help to mitigate the impacts of potential construction noise. Hours of operation will be posted on-site. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site(s) are currently used as single family residences. One of the existing properties contains a barn and other outbuildings associated with the keeping of live stalk. Adjacent land uses consist of a low density single- family residence. The existing plat of Liberty Lane is located to the east and the proposed plat of Evendell is located to the west. b. Has the site been used for agriculture? If so, describe. It is not believed that the site was utilized for agricultural production in the past. c. Describe any structures on the site. The property on the east side of 160'" Ave. SE, "Liberty Grove Contiguous" (145750-0085 & -0090) contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home on lot -0085 and all the associated outbuildings are proposed for removal. • 1,240 SF home located at13612160TH AV SE 98055 (145750-0085) • 2,410 SF home located at 13644 160TH AV SE 98055 (145750-0090) d. Will any structures be demolished? If so, what? Yes. One of the homes and all of the out buildings are proposed for removal. e. What is the current zoning classification of the site? The project site is currently zoned R-4. The applicant has submitted a proposal to rezone the property as R-6 or utilize the Counties TOR program to achieve the desired lot count. f. What is the current comprehensive plan designation of the site? According to the King County Comprehensive Land Use Plan, the area is designated Urban Residential -R 4-12. This designation would support the proposed rezone of the property. g. If applicable, what is the current shoreline master program designation of the site? 10 FOR AGENCY USE ONLY LGC REVISED 09103/03 Not applicable. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. According to the 1990 King County Sensitive Areas Folio no part of the property has been designated as sensitive. However, field investigation has identified a low value, minor Class 3 wetland feature on-site. The feature is located in the south-central segment of the project site. See attached Wetland Report. An addendum wetland study has been provided in response to Staff comments. i. Approximately how many people would reside or work in the completed project? Assuming 2.5 persons per household, approximately 90 people would reside in the proposed project. j. Approximately how many people would the completed project displace? 2.5 k. Proposed measures to avoid or reduce displacement impacts, if any: The proposed project will provide 35 ~ housing units, 36 total. I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The project will be developed in accordance with applicable King County development and land use codes to ensure the project is consistent with the goals and policies of the Comprehensive Plan and applicable development regulations in effect at the time of a complete Preliminary Subdivision application. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Approximately 35 (36 total) new middle-income housing units will be provided. b. Approximately how many units, if any would be eliminated? Indicate whether high, middle, or low-income housing. Two middle income homes will be removed. c. Proposed measures to reduce or control housing impacts, if any: Adherence to the comprehensive plan and growth management planning goals of King County would ensure that housing development is consistent with those policies stated in the applicable land use plan. 35 new homes will be built. 11 FOR AGENCY USE ONLY LGC REVISED 09/03/03 1 O. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? No specific building plans are included with this project; however, it is anticipated that houses built on the site would confonm to the King County development regulations and be limited to a height of 35 feet in accordance with 21A.12.030. b. What views in the immediate vicinity would be altered or obstructed? Development of the site would result in a change to the visual character of the site for the nearest existing residences and roadways to that of a single- family neighborhood area. No significant views would be obstructed. c. Proposed measures to reduce or control aesthetic impacts, if any: The site plan has been developed to provide a site design layout consistent with the development regulations in place for the R-4 and/or R-6 zone. The proposed project incorporates landscape and open space areas in accordance with King County development regulations. 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Light and glare from the completed project is anticipated to be that typically generated by single-family residences, mainly occurring during the evening hours, and be associated with vehicle headlights, streetlights and residential unit lighting. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not under nonmal circumstances. c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Installation of front yard trees along the street frontages and landscaping in open space areas will help to alleviate some of the light and glare created by streetlights, headlights and residential unit lighting from the adjacent properties. The proposal will only install those street lights approved by King County and Puget Sound Energy. Typical streetlights would consist of a 150-watt, flat lens luminaire located atop a 25' light standard. 12 FOR AGENCY USE ONLY LGC REVISED 09/03/03 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? There are currently no public recreation facilities in the immediate vicinity of the site. Undeveloped King County park land lies approximately 2000' west of the site. Maplewood Park is about 1 mile southwest of the site. Maplewood Heights park is .4 miles southeast of the site. b. Would the proposed project displace any existing recreational uses? If so, describe. The project would not displace any existing recreational uses. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: The proposed project will provide a minimum of 390 square feet of open space/recreation area per single-family lot (13,650 SF) pursuant to 21A.14. The applicant proposes to construct recreational facilities on site or pay the appropriate fee-in-lieu of recreational facilities to offset any potential adverse impacts of the project. Many of the required recreational facilities required for the plat of Liberty Grove are proposed to be located in conjunction with the facilities provided by the plat of Liberty Grove Contiguous. This will allow for a more unified and centralized recreational opportunity. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. None known. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. To the best of our knowledge, there are no landmarks or evidence of any significant historic, archaeological, scientific or cultural resources known to be on or next to the site. c. Proposed measures to reduce or control impacts, if any: If any such historic or cultural evidence is encountered during construction or installation of improvements, work would be halted in the area and a state-approved archaeologist/historian would be engaged to investigate, evaluate and/or move or curate such resources, as appropriate. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. 13 FOR AGENCY USE ONLY LGC ::,, _J.7D ... 'ber':y Crave CG:lllQUC•US ;:;;it:lim 1 r::ory F>,: i<!ng CcL:n(y SEPA ,:~.11ec>1.si REVISED 09/03103 The proposed project will take primary access from 160th Ave SE. Secondary access for the east portion of the plat will come from SE 136th Street. Please see the attached traffic report for more details. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No. The nearest transit stop is located near the .comer of SE 128th Street and 160th Ave SE, approximately .46 miles away from the project site. The Metro bus rout providing service to that stop is #111. There is no bus shelter provided at that location. c. How many parking spaces would the completed project have? How many would the project eliminate? None. The proposed project will provide parking in private driveways, garages and on-street parking. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). Yes, the e,roposed project will require improvement of public right-of-way along 160 Ave. SE & SE 1361" Street and construction of internal circulation roads and access tracts. All roads will be designed and constructed to current King County standards. 160th Ave. SE will be designed to the Urban Collector standard. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Assuming 10 trips per household per day, the completed project will generate approximately 360 vehicular trips per day. Please refer to the attached Traffic Report for specific details. g. Proposed measures to reduce or control transportation impacts, if any: The applicant or subsequent owner(s) will comply with Title 14 of the King County Code, which contains provisions for payment of MPS (Mitigation Payment System) Fees. Applicant will either pay the MPS fee at the time of final plat application or at the time of building permit application. If the first option is chosen, the fee paid will be the fee in effect at the time of plat application, and a note will be placed on the face of the plat stating, "All Mitigation Payment System Fees required by Title 14 have been paid." If the second option is chosen, the MPS fee paid will be the fee in effect at the time of building permit application. Contributions to projects listed in the MPS program may receive credit towards the MPS payment due. The estimated MPS fee for this project at the time of application will be, based on 14 FOR AGENCY USE ONLY LGC REVISED 09/03103 a 35 NEW (36 total) unit subdivision. The project lies within MPS zone # 452, which has a fee of $2,139 per new single-family unit. Based on 35 new units, the projected total MPS fee is $74,865. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. The completed project would result in an increased need for police and fire protection as well as emergency medical service. Additional recreational and school facilities will also be required to address the increase in demand for recreational opportunities. Extension of public sewer and water service will also be reguired. b. Proposed measures to reduce or control direct impacts on public services, if any. The project will be designed and constructed with adequate water pressure, properly located fire hydrants and roadways constructed to allow adequate access for fire, medic and police protection vehicles. Increased property valuation will result in increased taxes generated to support public services. Sewer service to the proposed project site will reguire extension of a 10" to 12" off-site sewer line from approximately 154'" Ave. SE to 162"a Ave. SE, within the existing SE 136'" Street right-of-way. Additional improvements ma~ include a 10" sewer main in 162"a St. SE .• and a 8" sewer main in 158"' & 160" Ave. SE. The proponent will pay necessary school and traffic mitigation fees to offset the potential impacts to the school and transportation system. The project is located in the Issaquah School District #411. The current school impact fee is $3,924 per single-family unit. Assuming 35 new units (36 total), the total school impact fee would be $137,340. Recreational facilities will be constructed on site in accordance with the requirements of 21A.14 to offset the potential impacts on the existing recreational system or a fee-in-lieu of those facilities will be offered. 16. Utilities a. Indicate utilities currently available at the site: Electricity, Natural Gas, Water, Telephone, Sanitary Sewer, Septic System, Refuse Service, Other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. 15 FOR AGENCY USE ONLY LGC REVISED 09/03103 Water System - Sanitary Sewer System - Storm Water - Electricity: Natural Gas: Telephone: Refuse Service: Cable TV: Water District #90 City of Renton -Extension of a10" to 12" sewer main in SE 136"' St., 10" sewer main in 162"• St. SE., and a 8" sewer main in 158 111 & 16o"' Ave. SE. King County Puget Sound Energy Puget Sound Energy Qwest Robanco AT&T Broadband All underground service will be constructed in conjunction with road and storm drainage construction activities C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Prepared: REVISED Hans A. Korve DMP., INC Planning Manager February 28, 2003 September 3, 2003 16 FOR AGENCY USE ONLY LGC .. ' -~--- ._ ,._ . --' '--. ~t with the development patterns of the surrounding area. The plat of Evendell located west of the Liberty proposal is currently being rezones from R-4 to R~ as well. 12. Location of the proposal. Provide a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if available. The subject proposal is situated on three parcels totaling 7 .92 acres, located within the jurisdictional boundaries of unincorporated King County in the SE Y, of Section 14 Township 23 North, Range 5 East W.M. The site is located on parcel(s) 145750-0085 and -0090. Please refer to the Preliminary Plat map for the legal description, site plan, vicinity map, and topographic map. The proposed Plat of Liberty Grove is located to the north on the west side of 160"' Ave. SE. 8. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one):( flat L (rolling[, hilly, steep slopes, mountainous. The project site is located on the east side of 160"' Ave. SE. (-0085 & -0090) and contains a few minor slopes in the northeast comer of the property and a non-jurisdictional drainage channel which extends through the center of the property, from north to south. The northeastern portion of the site is classified as forested uplands. The remainder of the property is pasture with two existing homes and out buildings. One Class 3 wetland has been identified in the south-central portion of the site. The finding and classification has been reviewed and approved by ODES staff. Please refer to the preliminary plat map for detailed contour information. b. What is the steepest slope on the site (approximate percent slope)? According to the field topographic survey, the steepest slope on the site is approximately 5% to 10% located northeast comer of the project site. c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, and muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. According to the US Soil Conservation Service Soil Map, the site is primarily Alderwood series (AgC) d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. According to the King County Sensitive Areas Map, the property contains no hazard areas. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. 3 FOR AGENCY USE ONLY LGC 2. Air ' ----. ·- Grading of the site will be necessary to modify the site for stormwater drainage flow. The exact quantity of grading is not known at this time, however, it is anticipated that the grading activities would be designed to balance and not require import or export of soil. Grading of the individual home sites will involve the excavation of approximately 150 to 200 CY of cut and/or fill. These issues will be addressed during the building permit phase. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Some erosion could occur on-site as a result of construction activities; however, temporary erosion and sedimentation control measures to be approved by King County will be employed to reduce erosion impacts. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Due to the preliminary nature of the plans, the exact percentage of impervious surface associated with this project is currently unknown. The subject proposal will not exceed the maximum impervious surface area as required by KCC 21A.12.030 h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, the contractor will follow an approved temporary erosion and sedimentation control plan meeting KCC standards. Typical measures, which may be employed, include the use of silt fences, straw bales, and temporary storm drainage features. Hydro seeding exposed soils and cleared areas after construction will also reduce the potential for erosion. All construction during the wet season will comply with the 1998 Surface Water Design Manual, Sections 5.4.8 and D.4.2.1A concerning site coverage techniques. a. What types of emissions to the air would result from the proposal ~.e., dust, automobile, odors, and industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Construction: Emissions and dust particulates generated primarily by construction equipment will be produced during the construction phase of this project. The amount of emissions to the air will be minimal and will occur during the actual construction of the development. 4 LGC FOR AGENCY USE ONLY Long Tenn Air Quality: Long-tenn air impacts would be those typically associated with residential land uses. Sources of long-term emissions and odor could include vehicle emissions from increased vehicle use generated by the new residential units and emissions from wood burning fireplaces (if permitted). The additional vehicular emissions in these areas are not anticipated to concentrate and therefore are not anticipated to create a health hazard to the residents or surrounding areas. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No. c. Proposed measures to reduce or control emissions or other impacts to air, if any: 3. Water If particulates become suspended during construction, frequent watering of the site during the construction phase of the project would be used to help control dust and other particulates generated on the site. This will be accomplished in accord with Section 5.4.7 of the 1998 Surface Water Design Manual. a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, Jakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. · According to the King County Sensitive Areas Folio, there are no recorded streams or other water bodies on the subject site. However, field investigation has revealed the presents of a single Class 3 wetland feature in the south-central section of the site. Habitat Technologies has completed a full wetland assessment and report. The report was reviewed and ;tpproved by DOES Staff on November 27, 2002. 2) Will the project require any work over, in or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. The Class 3 Wetland, identified in the wetland report will be preserved and accorded the appropriate 25' buffers and 15' building setback. Grading and other construction activities are expected within 200' of the wetland feature but outside the required buffers. Appropriate measures will be taken to insure the integrity of the wetland feature during construction. Refer to the attached wetland report for complete details. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Creation of the proposed single-family lots will not require the adverse impact or placement of fill within identified wetland areas or buffers. 5 FOR AGENCY USE ONLY LGC 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan According to the King County Sensitive Areas Maps, no portion of the site lies within the 100..foot flood plain. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No. b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. None known at this time. c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. On-site storm water runoff will primarily be generated from roadways, residential structures, and associated driveways. Storm water will be collected in catch basins within the roadways and/or tight-lined from residential roof tops and conveyed to a proposed detention facility located on the project site (southwest comer of -0090). Storm water from the proposed plat of "Liberty Grove" will be transferred along 160th Ave. SE and processed in the single stormwater facility located on parcel -0090. Discharge from the proposed facility will be piped into the existing storm water system. Refer to the attached Level 1 storm water report for complete details. 2) Could waste materials enter ground or surface waters? If so, generally describe. Some pollutants normally associated with residential development could enter the surface water; however, the amount would be minimal since the 6 FOR AGENCY USE ONLY LGC 1) Describe special emergency services that might be required. In the event that environmental health hazards are encountered or occur during construction, all appropriate precautionary measures will be employed. Any emergency situation would be addressed by the existing resources of Fire District #25. 2) Proposed measures to reduce or control environmental health hazards, if any: State regulations regarding safety and the handling of hazardous materials will be followed during the construction process. Equipment refueling areas would be located in areas where a spill could be quickly contained and where the risk of hazardous materials entering surface water is minimized. On-site management will be equipped with mobile communications equipment at all times to contact emergency services in the event of an incident. b. Noise 1) What types of noise exist in the area. which may affect your project (for example: traffic, equipment operation, other)? The dominant source of noise in the project vicinity is traffic along 160"' Ave. SE, which bisects the proposed project. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation. other)? Indicate what hours noise would come from the site. Short-term impacts would result from the use of construction equipment during site development. Construction would occur during permitted construction hours and in compliance with King County noise standards. 3) Proposed measures to reduce or control noise impacts, if any: Construction activity will be limited to permitted construction hours and construction equipment will not be allowed to idle for continuous periods of time, which will help to mitigate the impacts of potential construction noise. Hours of operation will be posted on-site. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site(s) are currently used as single family residences. One of the existing properties contains a barn and other outbuildings associated with the keeping of live stalk. Adjacent land uses consist of a low density single- family residence. The existing plat of Liberty Lane is located to the east and the proposed plat of Evendell is located to the west. 9 FOR AGENCY USE ONLY LGC b. Has the site been used for agriculture? If so, describe. It is not believed that the site was utilized for agricultural production in the past. c. Describe any structures on the site. The property on the east side of 160th Ave. SE , "Liberty Grove Contiguous" (145750-0085 & -0090) contains two existing homes and associated outbuildings. The home located on parcel -0090 is proposed to remain. The additional home on lot -0085 and all the associated outbuildings are proposed for removal. • 1,240 SF home located at13612 160TH AV SE 98055 (145750-0085) • 2,410 SF home located at 13644160TH AV SE 98055 (145750-0090) d. Will any structures be demolished? If so, what? Yes. One of the homes and all of the out buildings are proposed for removal. e. What is the current zoning classification of the site? The project site is currently zoned R-4. The applicant has submitted a proposal to rezone the property as R-6. f. What is the current comprehensive plan designation of the site? According to the King County Comprehensive Land Use Plan, the area is designated Urban Residential -R 4-12. This designation would support the proposed rezone of the property. g. If applicable, what is the current shoreline master program designation of the site? Not applicable. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. According to the 1990 King County Sensitive Areas Folio no part of the property has been designated as sensitive. However, field investigation has identified a low value, minor Class 3 wetland feature on-site. The feature is located in the south<entral segment of the project site. See attached Wetland Report. i. Approximately how many people would reside or work in the completed project? Assuming 2.5 persons per household, approximately 90 people would reside in the proposed project. j. Approximately how many people would the completed project displace? 2.5 k. Proposed measures to avoid or reduce displacement impacts, if any: 10 FOR AGENCY USE ONLY LGC The proposed project will provide 35 new housing units, 36 total. I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The project will be developed in accordance with applicable King County development and land use codes to ensure the project is consistent with the goals and policies of the Comprehensive Plan and applicable development regulations in effect at the time of a complete Preliminary Subdivision application. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Approximately 35 (36 total) new middle-income housing units will be provided. b. Approximately how many units, if any would be eliminated? Indicate whether high, middle, or low-income housing. Two middle income homes will be removed. c. Proposed measures to reduce or control housing impacts, if any: Adherence to the comprehensive plan and growth management planning goals of King County would ensure that housing development is consistent with those policies stated in the applicable land use plan. 35 new homes will be built. 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? No specific building plans are included with this project; however, it is anticipated that houses built on the site would conform to the King County development regulations and be limited to a height of 35 feet in accordance with 21A.12.030. b. What views in the immediate vicinity would be altered or obstructed? Development of the site would result in a change to the visual character of the site for the nearest existing residences and roadways to that of a single- family neighborhood area. No significant views would be obstructed. c. Proposed measures to reduce or control aesthetic impacts, if any: The site plan has been developed to provide a site design layout consistent with the development regulations in place for the R-4 and/or R-6 zone. The proposed project incorporates landscape and open space areas in accordance with King County development regulations. 11 FOR AGENCY USE ONLY LGC 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Light and glare from the completed project is anticipated to be that typically generated by single-family residences, mainly occurring during the evening hours, and be associated with vehicle headlights, streetlights and residential unit lighting. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not under nonnal circumstances. c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Installation of front yard trees along the street frontages and landscaping in open space areas will help to alleviate some of the light and glare created by streetlights, headlights and residential unit lighting from the adjacent properties. The proposal will only install those street lights approved by King County and Puget Sound Energy, Typical streetlights would consist of a 150-watt, flat lens luminaire located atop a 25' light standard. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? There are currently no public recreation facilities in the immediate vicinity of the site. Undeveloped King County park land lies approximately 2000' west of the site. Maplewood Park is about 1 mile southwest of the site. Maplewood Heights park is .4 miles southeast of the site. b. Would the proposed project displace any existing recreational uses? If so, describe. The project would not displace any existing recreational uses. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: The proposed project will provide a minimum of 390 square feet of open space/recreation area per single-family lot (13,650 SF) pursuant to 21A.14. The applicant proposes to construct recreational facilities on site or pay the appropriate fee-in-lieu of recreational facilities to offset any potential adverse impacts of the project. Many of the required recreational facilities required for the plat of Liberty Grove are proposed to be located in conjunction with the facilities provided by the plat of Liberty Grove 12 FOR AGENCY USE ONLY LGC Contiguous. This will allow for a more unified and centralized recreational opportunity. 13. Historic and Cultural Preseivation a. Are there any places or objects listed on, or proposed for, national, state, or local preseivation registers known to be on or next to the site? If so, generally describe. None known. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. To the best of our knowledge, there are no landmarks or evidence of any significant historic, archaeological, scientific or cultural resources known to be on or next to the site. c. Proposed measures to reduce or control impacts, if any: If any such historic or cultural evidence is encountered during construction or installation of improvements, work would be halted in the area and a state-approved archaeologist/historian would be engaged to investigate, evaluate and/or move or curate such resources, as appropriate. 14. Transportation a. Identify public streets and highways seiving the site, and describe proposed access to the existing street system. Show on site plans, if any. The proposed project will take primary access from 160"' Ave SE. Secondary access for the east portion of the plat will come from SE 136"' Street. Please see the attached traffic report for more details. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No. The nearest transit stop is located near the comer of SE 128"' Street and 160"' Ave SE, approximately .46 miles away from the project site. The Metro bus rout providing seivice to that stop is #111. There is no bus shelter provided at that location. c. How many parking spaces would the completed project have? How many would the project eliminate? None. The proposed project will provide parking in private driveways, garages and on-street parking. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). Yes, the proposed project will require improvement of public right-of-way along 160"' Ave. SE & SE 136"' Street and construction of internal circulation roads and access tracts. All roads will be designed and constructed to 13 FOR AGENCY USE ONLY LGC current King County standards. 160"' Ave. SE will be designed to the Urban Collector standard. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Assuming 10 trips per household per day, the completed project will generate approximately 360 vehicular trips per day. Please refer to the attached Traffic Report for specific details. g. Proposed measures to reduce or control transportation impacts, if any: The applicant or subsequent owner(s) will comply with Title 14 of the King County Code, which contains provisions for payment of MPS (Mitigation Payment System) Fees. Applicant will either pay the MPS fee at the time of final plat application or at the time of building permit application. If the first option is chosen, the fee paid will be the fee in effect at the time of plat application, and a note will be placed on the face of the plat stating, "All Mitigation Payment System Fees required by Title 14 have been paid." If the second option is chosen, the MPS fee paid will be the fee in effect at the time of building permit application. Contributions to projects listed in the MPS program may receive credit towards the MPS payment due. The estimated MPS fee for this project at the time of application will be, based on a 35 NEW (36 total) unit subdivision. The project lies within MPS zone # 452, which has a fee of $2,139 per new single-family unit. Based on 35 new units, the projected total MPS fee is $74,865. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. The completed project would result in an increased need for police and fire protection as well as emergency medical service. Additional recreational and school facilities will also be required to address the increase in demand for recreational opportunities. b. Proposed measures to reduce or control direct impacts on public services, if any. The project will be designed and constructed with adequate water pressure, property located fire hydrants and roadways constructed to allow adequate access for fire, medic and police protection vehicles. Increased property valuation will result in increased taxes generated to support public services. The proponent will pay necessary school and traffic mitigation fees to offset the potential impacts to the school and transportation system. The project is located in the Issaquah School District #411. The current school impact FOR AGENCY USE ONLY 14 LGC fee is $3,924 per single-family unit. Assuming 35 new units (36 total), the total school impact fee would be $137,340. Recreational facilities will be constructed on site in accordance with the requirements of 21A.14 to offset the potential impacts on the existing recreational system or a fee-in-lieu of those facilities will be offered. 16. Utilities a. Indicate utilities currently available at the site: Electricity, Natural Gas, Water, Telephone, Sanitary Sewer, Septic System, Refuse Service, Other. b. Descrtbe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water System - Sanitary Sewer System - Stonn Water - Electricity: Natural Gas: Telephone: Refuse Service: Cable TV: Water District #90 City of Renton -Extension of a 12" sewer main in SE 136"' St, 10" sewer main in 162"• St. SE., and a 8" sewer main in 158"' & 16o"' Ave. SE. King County Puget Sound Energy Puget Sound Energy Qwest Robanco AT&T Broadband All underground service will be constructed in conjunction with road and stonn drainage construction activities C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Prepared: d Hans A. Korve OMP., INC Planning Manager February 28, 2003 15 FOR AGENCY USE ONLY LGC DO NOT USE THIS SHEET FOR PROJECT ACTIONS Rezone Request from R-4 to R-6 Parcel(s) # 14570-0085, -0090 and 366450-0141 D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water; emission to air; production, storage, or release of toxic or hazardous substances; or production of noise? This proposal is to rezone 12.76 acres of R-4 land into R-6. The approved rezone would result in a minimal increase in the amount of water or air discharge from the project. The current comprehensive plan designation is for urban residential development at densities ranging from R-4 to R- 12. Achieved density is increasing from the current 4 units/acre to the proposed 4.7 units/acre. This proposed rezone would be consistent with that designation. Proposed measures to avoid or reduce such increases are: All development will be in accord with the adopted King County Development standards. Stormwater collection and discharge will be in accord with the 1998 Surface Water Design Manual. 2. How would the proposal be likely to affect plants, animals, fish, or marine life? The proposed rezone will have no new significant impact on the existing plant or animal populations. With or without the proposed rezone, the subject property will be developed to its highest and best use. All sensitive areas will maintain the same level of integrity with or without the approval of the proposed rezone. Proposed measures to protect or conserve plants, animals, fish, or marine life? All sensitive areas will be protected in accord with the provisions of 21A.24.320. All retained sensitive areas will be provided appropriate buffers. All storm water will be detained and treated in accord with the 16 FOR AGENCY USE ONLY LGC 1998 King County Surface water Design Manual and will not adversely effect the retained sensitive areas. Wetlands will only be altered in accord with KCC 21A.24.330. 3. How would the proposal be likely to deplete energy or natural resources? Electrical energy will be the primary source of power serving the needs of the project and natural gas will be made available for the purpose of heating and other needs associated with residential living. Electricity can be generated from renewable power sources such as hydro power. Proposed measures to protect or conserve energy and natural resources are: The proposed residential buildings for this project will meet or exceed the applicable single-family residential energy conservation / consumption requirements in King County and the Uniform Building Codes. 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? Therefore, there will be no increased impact to sensitive areas as a result of this rezone application. The sensitive areas on site will be protected under the provisions of KCC 21A. regardless of zoning classification. Any modification to the existing sensitive areas will be in accord with 21A.24.330. Proposed measures to protect such resources or to avoid or reduce impacts are: All development will be in accord appropriate buffers and setbacks. provided if required. with 21A.24.320 and provided the Additional buffer planting may be 5. How would the proposal be likely to affect land and shoreline use, including whether it would allow or encourage land or shoreline uses incompatible with existing plans? None The proposed rezone is consistent with the current Comprehensive Plan. Proposed measures to avoid or reduce shoreline and land use impacts are: None 17 LGC FOR AGENCY USE ONLY 6. How would the proposal be likely to increase demands on transportation or public services and utilities? The proposed development will have the effect of locally increased traffic and population which will increase the demand on existing services from the currently allowed 51 single-family residences to the proposed 60. Proposed measures to reduce or respond to such demand(s) are: Neighborhood tax revenues, taken together with Traffic and School related mitigation fees, will provide funds to continue the municipal services offered to the existing neighborhood and surrounding area. Development of the Liberty Grove project will also require improving existing unimproved or marginally improved King County right-of-way adjacent to the subject property. Primary access to both segments of the subject property will come from 1601 h Ave. SE. Secondary access to the eastern portion of the subject property will come from SE 136'" Street. Frontage improvements contemplated for this project include: • Construct half-street urban neighborhood collector road improvements along the project frontage on SE 1361 h Street. The existing KC right-of-way along the northern frontage is 30'. • Construct half-street urban neighborhood collector road improvements along the project frontage on 160th Ave. SE. The existing KC right-of-way along the east and west frontage is 30' on either side. Applicant proposes to participate in the construction of the nearby Evendell sewer lift station. Completion of this facility will allow access to approximately 37 acres of land currently serviced by on-site septic systems, some of which are currently failing. In addition, several hundred acres to the north will be able to connect via gravity sewer mains to the gravity portion of the sewer system to be constructed by the Subject Plat and the Plat of Evendell as part of the SE 136th Street improvements. The proposed subdivision will also bring with it on-site recreational facilities which are currently unavailable to the immediate surrounding properties. 18 FOR AGENCY USE ONLY LGC 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the environment. None The Zoning Map amendment requested is needed to attain the residential density goals prescribed for the area in question, as currently designated within the King County Comprehensive Plan Map. Urban residential R-4 to 12 The re-designation of the subject property from R-4 to R-6 on the Zoning map will enable the property in question and the surrounding properties to be built out more in keeping with their maximum potential on land that is well suited for this level of density. • The proposed rezone is consistent with the current Comprehensive plan. • The proposed rezone and subsequent development will be consistent with development in the vicinity. • The proposed rezone will have no additional unmitigated impact on the transportation system beyond what would be allowed under current density limits. • The proposed rezone will not have an adverse affect on the general health, safety or welfare of the citizens of King County 19 FOR AGENCY USE ONLY LGC King County Road Services Division Department of Transportation ZOI South Jackson Street Seattle. WA 98104-3856 TYPE OF CERTIFICATE [gJ ORIGINAL 0 CONDITIONAL May 23, 2002 Certificate # 01405 File Number: 02-05-21-02 Exoires: Mav 23 2003 CERTIFICATE OF TRANSPORTATION CONCURRENCY D Specific conditions are described on the reverse side of this certificate. Pursuantto King County Code, Chapter 14.70 as amended, this certificate confirms that the level of service standard used in the Transportation Concurrency Management program has been satisfied and sufficient road capacity is reserved for the development project described below. IMPORTANT: This certificate does not guarantee a development permit. Other transportation improvements and mitigation will be required to comply with Intersection Standards, Mitigation Payment System, King County road standards, and/or safety needs. I. Applicant Name and Address: WM Wayne Jones, Jr., Lakeridge Development, Inc. PO Box 146, Renton, WA 98057 2. Property Location: a. Property Address: 13612 160th Avenue SE b. Development Name: c. Parcel Number: 1457500085,90;3664500141 3. Type of Development Permit To Be Requested: Formal Plat 4. Proposed Land Use: Single Family Residential 5. ~one ~~a~i~n-and R~~e~ed Uni~~ ~~~~~~~f(J' MAR 1 1 2003 /.W a. Concurrency Zone: 763 Community Planning Area: Newcastle . i. Commercial Project-Total Square Feet: 0 'ii. Multi-family -Nuriiber of Units: Cl K.C. D.D.E.S . iii. Single fumily-Number of Units: 60 6. This Certificate is subject to the following general conditions: a. This Certificate of Concurrency runs with the land and is transferable only to si.tbsequent owners of the same property for the stated developfilent, subjeCt to the terms. conditions and expiration date listed herein. This Certificate of Concurrency is not transferable to any other property and has no commercial value. This Certificate Expire~3, 20~ . . . · unless you apply for the development permit described above? prior to that date. If this requirement is not met the King County Department of Transportation reserves the option to cancel your certificate and capacity reservation. When you apply for a development permit with King County's Department of Development and Environmental Services (DDES), bring this Certificate of Transportation Concurrency as part of the development application package. If you have any questions, please call (206) 263-4722. Linda Dougherty, Manager, Rood Services Div1s1on Department of Transportation King County, Washington ,t\ FILE COPY *11~/ting REc., .. ,,_., FILE copy July 18,2003 SEP 03 ?003 L08P0005 /\11 •~ -.<)UlilY LAND USE SERVICES Mr. Wayne Jones Lakeridge Development Inc. P.O. Box 146 Renton, Washington 98057-0146 [REVISION] RE: Additional Sensitive Area review for IJberty Plat, King County submittal L03P005 & L03P006 Dear Mr. Jones, In response to the letter of from King County staff I have conducted an additional review to assess the area cited in the letter as requiring additional assessment. Please consider this an addendum to the WETLAND EVALUATION AND DELINEATION REPORT AND WILDLIFE HABITAT EVALUATION, LAKERIDGE PROJECT SITE, by Habitat Technologies, November 5, 2002. The area noted in the response is located in the southeast portion of the eastern portion of the project site (see attached map). Onsite assessment of the project site following the procedures outlined in the Washington State Wetlands Identification and Delineation Manual (Wash. Manual) and the Corps of Engineers Wetlands Delineation Manual (1987 Manual) resulted in the identification of NO area that exhibited hydric soils, wetland hydrology, and hydrophytic vegetation consistent with the established criteria of both the Wash. and 1987 Manuals. This area had been impacted by prior grazing and pasture management activities, and active and on-going lawn and pasture management. ONSITE EVALUATION -WETLANDS Onsite assessment and evaluation was conducted on July 7, 2003. Wetland assessment within the project site followed the methods and procedures outlined in both the Wash. Manual and the 1987 Manual. The site is an open meadow, until recently utilized as a livestock pasture. A road drain passes under 162nd Avenue at the junction with 136th Street. This roadside ditch continues south along the side of the road thru approximately the north one-half of the project site. At approximately the northern boundary of the pasture, it turns slightly southeast and transects the southeastern portion of the project site. Rom the southern boundary of the project site, a ditch conveys surface water west to a culvert south of the eastern portion of the project site. P. 0. Box 731695 • Puyallup WA 98373 02154Lakeridge-1 ~ 253-732-6515 mheckert@qwest.net 360~?f.l'~~!}ll'.lffi~E C Y ).. y( ,I FIELD OBSERVATION • Vegetation A mature managed pasture/lawn plant community dominated the evaluation site. This plant community was composed of a wide variety of invasive and seeded grasses. This plant community included colonial bentgrass (Agrostis tenuis), meadow foxtail (Alopecurus pratensis), velvet grass (Holcus /anatus), reed canarygrass (Phalaris arundinacea), bluegrass (Poa spp.), fescue (Festuca spp.), orchardgrass (Dactylis g/omerata), quackgrass (Agropyron repens), bracken fern (Pteridium aqui/ium), western yarrow (Achillea lanulosa), thistle, cats-ear (Hypochaeris spp), softrush (Juncus effusus), tansy (Tanacetum vulgare), dandelion (Taraxacum officinale), buttercup (Ranunculus repens), curled dock (Rumex crispus) and clover (Trifolium spp.). These mature trees formed open stands across the treed portion of the site. A few mature Douglas-fir trees were present along the western boundary. Additional tree species occurring onsite included Western red cedar (Thuja p/icata) Sapling red alder (A/nus rubra) were colonizing the meadow, black cottonwood (Popu/us trichocarpa), cherry (Prunus spp), and cascara (Rhamnus purshiana). This plant community was identified as non-hydric (i.e. typical of uplands) in character. • Soils As identified by four sample plots (data attached) throughout the project site, the site exhibited a soil profile typical of the Alderwood soil series. The soil was defined as gravelly sandy loam with a soil matrix color of dark brown (10YR 3/2) to brown (10YR 4/4). These soils did not exhibit redoximorphic features such as prominent soil mottles, oxidized root channels, or glayed soil layers within the first 20 inches of soil depth. Soils within this area did not exhibit "hydric" characteristics. • Hydrology Along the western boundary of the evaluation site, evidence of the passage of water was documented. A culvert passed under 162"d Ave. (flowing west). This surface drainage was contained in a ditch flowing south along the road to approximately half way through the evaluation area. The drainage curved slightly to the west and through the southern portion of the site. In the southern portion, the drainage ditch became less defined, and continued to the southern boundary in an undefined channel swale. From the southern boundary, the surface flow was collected into a defined ditch which flowed west to a culvert inlet. This drainage appeared to be created within an upland area, as evidenced by the soils, and was assuming hydric characteristics as a result of the direction of roof and street runoff through the site. 02154 Lakeridge • 2 Addendum We~and Report FINDINGS AND CONCLUSIONS Onsite assessment was completed on July 7, 2003 following the methods and procedures defined within both the Wash. Manual, the 1987 Manual, and the WDNR Forest Practice Rules. This assessment identified that no area on the site, or within the immediate vicinity of the project site, exhibited all three of the established criteria for designation as ''wetland". The entire site would be best defined as upland unmanaged pasture. No area was identified onsite that would meet the criteria for designation as a "stream." Thank you for allowing H & S the opportunity to assist with this project. Should you have any questions or require additional assistance please call me at 253 732-6515. ~//#f Mark Heckert Senior Wetlands Ecologist 02154 Lakeridge -3 Addendum WeUand Report Data Form Routine Wetland Determination Project/Site: Liberty Lakeridge Applicant/Owner: Lakridge Development Investigator: M. Heckert [X] Do nonnal circumstances exist on the site? Job Numbe~ 02154 City: Wetland Data Point SP 201 Date: July 07, 2003 County: King State: WA [ J Have vegetation, soils, or hydrology been disturbed? [ J Is the area a potential problem area? Community ID: Meadow Station ID: Plot ID: Vegetation Dominant S~Jes ----·------------------_ _Qommon_Name_ .. ___ . ----~-----__ _ _ _ % Cover__ Indicator _ Herbaceous X Agrostis Tenuis Sibth. X Dacty/is glomerata SbDJb. Rubus procerus 1iB Bentgrass,Colonial Grass.Orchard Blackbeny,Himalaya 50 FAC 50 FACU 10 NI _ X ________ PseudotsurmfifenziesiL(Mirbe/l_ _____________ f]r_,l)o_!!g!as_ 25 ______ FAC:1,J' Cowardifl ClaSSification: % Species that are OBL, FACW, or FAC(excepl FAG-): 33 Remarks appears to drain well Hydrology [X] Recorded Data (describe in remarks) [ ] Stream, Lake, or llde Gage [ J Aerial Photograph [ J Other (describe in remarks) Field Observations: Depth of Surface Waler(in.): o Depth to Free Water in Pit(in.): >24 Depth to Saturated Solls(in.): >24 Remarks up slope of ditched swale Soils Primary Wetland Hydrology Indicators ( J Inundated ( J Saturated in upper 12 inches [ ] Water marks [ J Drift lines [ J Sediment deposits [ J Drainage patterns in wetlands Secondary Hydrology Indicators [ J Oxidized root channels [ J Water-stained leaves [ J Local soil survey data [ J FAG-Neutral test [ J Other (explain in remarks) Depth Hor. Matrix Mottle I 2nd Mottle Texture, {[!L __ ~s Color . _________ C9lor ____ Abundance ____ Contrast ------~Structure,etc. 0-8 A I OYR 3/2 Sandy Loam pebbles 8-16 B 10YR414 Coarse Sandy Loam Hydric Soils Indicators [ J Histosol [ J Hislic Epipedon [ ] Sulfidic Odor .. [ J Probable Aquatic Moist Regime · [ J Reducing Conditions ( J Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks appears to drain well Wetland Determination [ J Hydrophytic Vegetation Present [ J Hydric Soils Present [ J Wetland Hydrology Present Remarks wetland criteria NOT met appears to drain well [ J Concretions [ ] High Organic % in Surface Layer [ J Organic Streaking [ J Listed on Local Hydlic Soils List [ J Listed on National Hydlic Soils Lisi ... [ J Other (explain in remarks) Taxonomy: [X] Field Observations match map [ J This Data Point is a Wetland Paae4 of4 Data Form Routine Wetland Determination Project/Site: Liberty l.akeridge Applicant/Owner: Lakridge Development Investigator: M. Heckert [X] c·o normal ci,:'rc .. u::m:::s=ta::nc_ces __ ex_i~st'_o_n...,tc-h-e-sc-ite---cc-? I ] Have vegetation, soils, or hydrology been disturbed? I ] Is the area a potential problem area? Vegetation Job Number: 02154 City: Wetland Data Point SP 202 Date: July 07, 2003 County: King State: WA Community ID: Meadow Station ID: Plot ID: Dominant S11!£!BS --------- Herbaceous -·-Common Name ___ ·------~-----·----% Cover ____ l!ld1c:ator __ X Lotus comicuJatus Trefoil,Birds-Foot FAC §bmb. X Rubus proceros Blackbeny,Himalaya _ X _____ Alnusmbra________________ AldeLRed __ 40 90 50 % Species that are OBL, FACW, or FAC(exoept FAC-): 66 Cowardin Classification: Remarks no sign of ponding Hydrology IX] Recorded Data (describe in remarks) I ] Stream, Lake, or Tide Gage I J Aerial Photograph I ) Other (describe in remarks) Field Observations: Depth of Surface Water(in.): 0 Depth to Free Water in Pit(in.): >24 Depth to Saturated Soils(in.): >24 Remari<s in swale appears to drain well Soils Primary Wetland Hydrology Indicators [ ) Inundated I J Saturated in upper 12 inches [ J Water mari<s I I Drift lines I I Sediment deposits [ J Drainage patterns in wetlands Secondary Hydrology Indicators [ ] Oxidized root channels I J Water-stained leaves I I Local soil survey data [ ] F AC-Neutral test I ] Other (explain in remarks) Depth Hor. Matrix Mottle/ 2nd Mottle Texture, (!tl.. _____ _,C"'o"lo'=r=~ 0--8 A 1 OYR 312 C~ntrast Structure, etc, _____________________ _ Color Abundance 8-16 A/B 10YR4/3 10YR 5/6 few faint ------------------------------------------------------·-·-----------·----,- Hydtic Soils Indicators I ] Histosol I ] Hlstic Epipedon I I Sulfidic Odor [ ] Probable Aquatic Moist Regime [ ] Reducing Conditions I J-Gleyed-or·Low-Chroma·Colors -Unit Name: Drainage Class: Remari(s ditched swale Wetland Detennination IX] Hydrophytic Vegetation Present I ] Hydric Soils Present I I Wetland Hydrology Present Remarks wetland criteria NOT met appear., to drain well [ ] Concretions I J High Organic % in Surface Layer I J Organic Streaking [ ] Listed on Local Hydric Soils List I J Listed on National Hydric Soils List I J Other (explain in remari<s) · Taxonomy: [X] Field Observations match map I · J This Data Point is a Wetland P~nA q nf ,4 Data Form Routine Wetland Determination Project/Site: Liberty Lakeridge Applicant/Owner: Lakridge Development Investigator: M. Heckert [XI Do nonnal circumstances exist on the site? - [ ] Have vegetation, soils, or hydrology been disturbed? [ ] Is the area a potential problem area? Vegetation Job Number: 02154 City: Wetland Data Point SP 203 Date: July 07, 2003 County: King State: WA · Community ID: station ID: Plot ID: Meadow Dominant S~es ______________ ... Common Name-----------·-·-·---% Cover Herbaceous X Phleum pratense Timothy X Juncus effusus Rush.Soft X Senecio jacobaea Tansy ragwort X Lotus comiculatus Trefoil,Birds-Foot _____ J?}JJnfB<XJ maigr -~,~~!ain,.Q_omm9_n __ _ % Species that are OBL, FACW, or FAC(exoept FAC-): 50 Remarks 30 40 20 30 10 Cowardin Classification: l_ndJcator __ FACU FACW+ UPL FAC _rn~+ Hydrology [X] Recorded Data (describe in remarks) [ J Stream, Lake, or Tide Gage Primary Wt/ttand Hydrology Indicators [ J Inundated Secondary Hydrology Indicators ( ] Oxidized root channels [ J Aerial Photograph [ ] Other (describe in remarks) Field Observations: Depth of Surface Water(in.): O Depth to Free Water in Pit(in_): >24 Depth to Saturated Soils(in-): >24 Remarks Soils [ J Saturated in upper 12 inches [ J Water marks [ I Drift lines ( J Sediment deposits [ ] Drainage patterns in wetlands [ J Water-stained leaves [ J Local soil survey data [ J FAG-Neutral test ( I Other (explain in remarks) Depth Hor. Matrix Mottle I 2nd Mottle Texture, ffi:!:.L ______ Color ~--Color ____ Abundance_ Contrast _ Structure, etc. --------------- 0-S A 1 OYR 3/2 Sandy Loam stones 8-16 B 10YR 4/3 Sandy Loam stones Hydric Soils Indicators [ J Histosol [ J Histic Epipedon [ I Sulfidic Odor -~-------~------ [ J Probable Aquatic Moist Regime ( ] Reducing Conditions .. [ i' Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks appears to drain well Wetland Detennination I ] HydrophyticVegetation Present [ J Hydric Soils Present ( J Wetland Hydrology Present Remarks wetland criteria NOT met appears to drain well ( J Concretions [ ] High Organic% in Surface Layer [ ] Oriianic Streaking ( J Listed on Local Hydric Soils List · · ( · ] ·Listed on National ·Hydric Soils List [ J other (explain in remarks) Taxonomy: [X] Field Observations match map [ ] This Data Point is a Wetland Paae2 of4 Data Form Routine Wetland Determination Project/Site: Liberty Lakeridgo ApplicanVDwner: Lakridge Development Investigator: M. Heckert (X] Do nomial circumstances exist on the site? · - [ J Have vegetation, soils, or hydrology been disturbed? [ J Is the area a potential problem area? Vegetation Job Number: 02154 City: Wetland Data Point SP 204 Date: July 07, 2003 County: King State: WA Community ID: Meadow Station ID: Plot ID: Dominant SpecJes -···--··-. ---------·--· Common Name ····---------~---% Cover _ Indicator _ Herbaceous X Agropyron repens X Agrostis Tenuis Sibth. X Lotus comiculatus X Alopecurus geniculatus filmlll. Quackgrass Bentgrass,Colonial TrefOll,Birds-Foot Foxtail,Meadow 20 20 60 30 FAGU FAG FAG FACW+ .. x ____ Rubus laciniatus ____ ·····-···----Blackberry,Cut-Leaf __ 30 . FACU+ % Species that are OBL, FACW, or FAC{except FAC-): 60 Cowardin Classification: · · Remants Hydrology [ ] Recorded Data {describe in remarks) [ J Stream, Lake, or Tide Gage [ J Aerial Photograph [ J Other {describe in remarks) Field Observations: Depth of Surface Water(in.): O Depth to Free Water in Pit(in.): >24 Depth to Saturated Soils{in.): >24 Remarks Soils Primary WeUand Hydrology Indicators [ J Inundated [ J Saturated in upper 12 inches [ J Water marks [ J Drift lines [ J Sediment dleposits l J Drainage patterns in wetlands Secondary Hydrology Indicators [ J Oxidized root channels ( J Water-stained leaves [ J Local soil survey data [ J FAG-Neutral test [ J Other (explain in remarks) Depth Hor. Matrix Mottle / 2nd Mottle Texture, Structure etc. (in.L____ Color ---·--Color Abundance Contrast 0-12 A 10YR 312 none 12-18 /VB 10YR 413 10YR 516 few faint Sandy Loam stones Sandy Loam stones Hydric Soils Indicators [ I Histosol [ J Histic Epipedon [ J Sulfidic Odor [ J Probable Aquatic Moist Reg_ime . [ J Reducing Co(iditions . . . [ J Gleyed or Low-Chroma Colors Unit Name: Drainage Class: Remarks sandy gravelly loam Wetland Determination (XJ Hydrophytic Vegetation Present [ J Hydric Soils Present [ J Wetland Hydrology Present Remarks Wetland criteria NOT met appears to drain well [ J Concretions [ ] High Organic % in Surface Layer [ J Organic Streaking ( . J Listed on Local HydFic Soils List . [ J Listed on National Hydric Soils List [ J Other (explain in remarks) Taxonomy: [X] Field Observations match map [ J This Data Point is a Wetland ,... ___ .. -" Jl ,._ -- ·,. 22 LOO&TBD IN TBB 80Ul1I HMM OJI' 8BCl'ION 8, '"'1vWN_,,..8BIP...,, ... Ill NOID'B, ·JIANGB 7 U8'1', WILUIIBTl'B MBBIDW DNG OOVN'IY, W.ASBING'.NJN -466--. ~ 21 ... EMOVE(\ JT~)zr ' 'f, 'SPED ., , DN trraffic Consultant~ PO Box 547 Preston, WA 98050-0547 425-392-1308 Date: To: From: Subject: April 17, 2007 Ty Pendergraft Eagle Creek Land Development Gary A. Norris, P.E., PTO.E. ON Traffic Consultants Threadgill/Ca valla/L iberty Gardens Response to KC Traffic Comment This memorandum was prepared to address a question raised by Kris Langley KCDOT, at the February meeting of the Threadgill et al applicants with King County DOES. Specifically, Kris requested an evaluation of the following: If signalization were warranted at the 156'" Avenue SE/SE 136'h Street intersection would: l. Would some of the southbound traffic demand shift from the 162nd Avenue SE/SE 144'" Strcct/156'h Avenue SE/SR 169 route to the SE 136'h Strect/156'" Avenue SE/SR 169 route? 2. What is your professional opinion about the reduction along 162nd Avenue SE and the increase along SE 136th Street, if any? To address these questions, I will respond in the order they are presented_ Signalization First, the questions are based on the premise that signalization would be warranted. A review of the prevailing traffic volumes and the MUTCD traffic signal warrants indicate the intersection does not meet applicable warrants in the 2008 with project volume scenario. Warrants considered included Warrant I -Eight Hour Warrant, Condition A and B; Warrant 2 -Four-Hour Vehicular Volume; Warrant 3 -Peak Hour; and Warrant 7 -Crash Experience. (There have been no accidents during the latest three year period evaluated). Projecting the 2008 with project volumes at the current growth rate (6 percent per year), signal warrants would be met in l 7 years or approximately 2025. Unless, the County is willing to consider signalization without warrants, it is unlikely that a signal will be constructed in the time frame of this development proposal_ \o) g@@ LJ W @@ lfU JUL O 2 2007 K.C, o.o.e.s. MAIN FILE COPY Southbound Trame Shit\ If the SE 136 1h Street/ 15(,'" Avenue SE intersection were signalized, it appears that the anticipated delay for eastbound and westbound traffic will be significantly higher than it currently rs under the two-way stop scenario. As presented iJ1 the TIA (Technical Appendrx), the approach delay for the eastbound and westbound traffic under the two- way stop control is 125.9 seconds and 63.9 seconds respectively. With signalization this increases to 40 I .4 seconds and 241.4 seconds respectively. This condition results from an optrmized signal timmg which seeks to minimize overall intersection delay Since the eastbound and westbound PM peak hour volumes are insignificant, 36 and 20 vph respectively, compared to the north and south bound traffic, 415 and 949 vph respectively, Syncro seeks to mu1imizc the delay by providing more "green time" to the north -south movement while the east -west movements wait. Therefore, if the signal were to operate in an optimized manner significant delay would be realized on SE l 36'h Street which would compel the motorist to seek other routes. An evaluation of the travel time via both routes indicates under normal circumstances, where the delay realized at the SE 136'h Street/156th Avenue SE intersection didn't have such an impact on route selection, the plat of Threadgill would select the SE 136'h Street/ l 56'h Avenue SE route to SR 169 whereas the other two plats, Liberty Gardens and Cavalla would select 162"d Avenue SE. This is based on the assumption that the motorist will select the minimum travel time path. Obviously, human nature doesn't always work that way. If the extension of 162"' Avenue SE is not constructed, then the SE 136'h Street/l 56'h Avenue SE route has the faster travel time for all three plats and it is assumed. Professional Opinion Regarding Diversion Based on the foregoing analysis and previous analysis of traffic flow patterns in this area, it is my opmron that tratric from these plats bound to/from the south and SR 169, will always seek alternative routes to the 156'" Avenue SE/SE 136'h Street route because of the delay encountered at this intersection. The construction of 162nd Avenue SE will not change this conclusion although it will offer a faster travel time for Cavalla and Liberty Gardens. The plat of Threadgill will not benefit from the construction of 162"d Avenue SE other than through the provision of another alternative route. I hope this addresses the question in a satisfactory manner. If you have any questions, please call me at (425)765-5721 or by e-mail at gary.norris@comcast.net. Thanks, Gary 2 (643) 676 _ 1 r (64) 378 --._ ' ~ ~ ijj :!.- "' -o"' L s--(0) 4 -"'"' ----(624) 1049 j t l t(9) 5J (I) 17 _j (891) 863 - (16) 63 t 1tr -cs L 1 j l -(633) 419 (6) 24 _j (190) 653 - S£ 128th Street (11) 13 _j (I) 1- (20) 22 t ... 1tr '° L ... <O «)!:;: 5' (9) 0 ----(4) 3 j t l t(3)1 (3) 4 _j (3) • -(12) 11 t 1tr (XXX) -AM PEAK XXX -PM PEAK DN TRAFFIC CONSULTANTS w "' w "' • , • C , • C > • "" > "" £ ~ 0 w ~ :; "' ~ • SE 132nd Street > C ~ < £ ~ !" SE 134th Street Threadgill Cavalla w "' • , C • > "" 5 w !" w V, • , C • > < £ m !" SE 136th Street £ m w Liberty Gardens S£ 144th Street 2008 TRAFFIC VOLUMES W/0 PROJECT FIGURE 6 PLAT OF THREADGILL CA VALLA LIBERTY GARDENS (4) 10-l "' §: SE 128th Street L(B) 6 .:. L <sH ~ ~ (8) 6 l ,(32) 21 {XXX) -AM PEAK XXX -PM PEAK r 117%/ w V> • ' C ~ < £ "' :" (4) 10 t lcae w (4) (8) d ,<2) 8 r "' E w V, • ' C • > < £ 0 :£ ~J (2) 2- (2) s, ~"'e d s7 (7) w V, • ' C • > < £ v :£ SE 132nd Street l~e SE: 134th Street S"'J ~-SThreadgill (46) .di w V, • ' C • > < E "' :" --(1) J 117%/ w V, • ' C • > < w £ V> • m ' :" C • > < £ m !!' sf'" (17) SE 136th Street ~~J t~~ Cavalla Liberty Gardens SE 144th Street w V, • ' C ~ < AM PEAK PM PEAK TOTAL OUT IN TOTAL OUT IN THREAOGIU. 10 3 7 14 9 5 CAVAU.A 26 7 19 34 21 13 LIBERTY GARDENS 29 8 21 38 24 14 DN TRAFFIC CONSULTANTS PROJECT GENERATED TRAFFIC PLAT OF THREADGILL CAVALLA LIBERTY GARDENS FIGURE 7 ... ~ ~ ';), SE 136TH ST u; '" -< I " < m Cf> m ?9 _.-'- ( I .1 11 I I CHAD ARMOUR, LLC May 16, 2007 Mr. Curtis Schuster KBS Develo~ment Corporation 12320 NE 81 Street, Suite 100 Bellevue, Washington 98005 Subject: Conceptual Wetland Mitigation Plan 162nd Avenue SE -Proposed Extension King County, Washington Dear Mr. Schuster: 6500 126'" Avenue S.E. Bellevue. Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com The following plan presents our approach to mitigating for unavoidable impacts to the buffer of Type 3 streams. We first looked for the opportunity to make up lost area on the site. Then, assuming that off-site mitigation is necessary and possible, we estimated the cost to rehabilitate an off-site degraded buffer. PROPOSED DEVELOPMENT PLAN Three different plats, Cavalla, Liberty Gardens, & Threadgill, are soon to be the location of single-family homes (Figure 1 ). Access to these plats is primitive or non-existent and will need to be constructed and upgraded. The preferred alternative to access these three sites is to construct a half a road (162nd Avenue SE) extending north from SE 144th Street. This road will be about 625 feet (ft) long and connect with the soon to be constructed 162°d Avenue SE along the western boundary of the Liberty Gardens Preliminary Plat (Figure 2). The road extension project for the three development proposals is being managed by KBS Development Corporation (Proponent). We understand that the streams associated with the 162nd Avenue SE extension is subject to the sensitive areas ordinance. We also understand that because there is not enough area available on site to make up for unavoidable impacts, additional mitigation will use the Mitigation Reserves Program. EXISTING CONDITIONS A Type 3 stream flows down the 162°d Avenue SE Right of Way (Figure 2 -Primary Type 3 Stream). The drainage originates north and west of the Right of Way (ROW). It is alternately located in a roadside ditch and buried culvert adjacent to 158th Avenue SE, SE 136th Street, and 160"' Avenue SE before it is discharged to the Smith property (Parcel No. 145750-0110). After flowing across the Smith property initially as sheet flow and then in a culvert/ditch system, it is discharged to an "engineered" ravine adjacent to Rich Lea Crest. Here the walls of the stream are short and steep and lined with quarry spalls. The stream turns south when it meets the 162°d Avenue SE ROW and flows through a deep narrow ravine. The stream discharges to an engineered (i.e., constructed) stormwater detention pond that is connected to an underground stormwater conveyance system that presumably dischar e~\1t~~ AIN FILE COPY C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.do 1 05116/07 Chad Armour, LLC J\,;L O £ 2007 K.C o.o.E.S 162°d Avenue SE Extension Mitigation Plan King County, Washington KBS Development Another Type 3 stream (Secondary Type 3 Stream) flows into the northern or upper end of the storm water retention pond. This stream crosses Liberty Gardens and a cleared area to the south before joining the Primary Type 3 stream. Stream Buffer The plant communities in the 162nd Avenue SE ROW adjacent to the stream include immature forest, a thick tangle of blackberry shrubs, and mowed grass. The buffer adjacent to the stormwater pond along the lower -250 ft of the ROW generally supports grass and a few Douglas-fir (Pseudotsuga menziesi1) trees. From the pond's eastern slopes and a point about -100 ft to the east the plant community includes a few deciduous trees growing through dense Himalayan blackberry (Rubus discolor) shrubs. The upper or northern -300 ft of the ROW is the location of an immature forest composed of big-leaf maple (Acer macrophyllum), Douglas-fir, black cottonwood (Popu/us balsamifera), and red alder (A/nus rubra) trees growing among a thick tangle of shrubs, including blackberries. In one location the back of a home and associated out building in Rich Lea Crest are located within a few feet of the west bank of the Primary Type 3 Stream. · CONCEPTUAL MITIGATION PLAN The plan is to: • Straighten the Primary Type 3 Stream; • Route the Secondary Type 3 Stream through a culvert; • Enhance the remaining available buffer following road construction; and • Pay the County a fee to enhance buffer off of the site. CONSTRUCTION PLAN The site is too small to accommodate mitigation entirely on the site. As such, the plan is to enhance as much of the degraded on-site buffer as possible (-15,000 square feet [sf]) and pay the County the equivalent fee to mitigate for buffer impacts that cannot be achieved on the ROW by enhancing 14,500 sf of degraded off-site buffer (Table 1). On-Site Buffer Enhancement We assume that machine encroachment will be limited to trackhoe excavators used to install snags and place logs. We also assume that most if not all of the crushed shrubs and herbs will naturally recover. We further assume that: • The blackberry shrubs will be removed to expose bare mineral soil and prepare the area for planting; • A total of 71 conifer and 54 deciduous trees will be installed individually 11 ft on center (OC) to increase tree density (Table 2); • A total of 490 shrubs will be installed in clumps 5 ft OC to promote a robust native shrub layer; • The ground will be covered (2'80%) with at least three different native herbaceous plant species; and • A total of 2 snags and 2 logs will be installed. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc 2 05/16/07 Chad Armour, LLC 00 :,-:..:.. " '-Q. 0 :!.>~ 80 cm ~ ?5 r., r< Cl"' I =,, ~ C i ~ ,,. 0 :l m cl ~ Table 2 -Plant and Habitat Amenity Installation Guide Total On-Site Buffer Off-Site Buffer 27 (6-8 ft; 11 ft oc 27 (6-8 ft; 11 ft oc 36 (6-8 ft; 11 ft oc 35 (6-8 ft; 11 ft oc clustered rose 193 Pacific ninebark 193 red-osier doQwood Comus stolonifera 193 ,western crabapple Ma/us fusca 193 ;Total Shrubs 965 • 15,000 sf; to be enhanced on-site b 14,500 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve c total average density is 0.041 plantslsf ;,; ~ -· a, ::, N CD a O:i, 0 < C: <I> ::, ::, '< C , <I> i~ ~m -· X :, m ca :, 0 (/1 :, -· 0 :, ~ i :, ,::, ~ i§ (J) 0 !1! 91. .g ~ :a 162°d Avenue SE Extension Mitigation Plan King County, Washington KBS Development It should be noted that mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this mitigation plan is the responsibility of the permitting authority. Accordingly, the mitigation plan developed for this road extension should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC ~ A"··~- Chad Armour Principal Attachments: Table 1 -Buffer impact and makeup areas Table 2 -Plant and Habitat Amenity Installation Guide Figure 1 -Vicinity Map Figure 2 -Site Plan Attachment A -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County DOES C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 6 05/16/07 FIGURES ON TRAFFIC CONSULTANTS VICINITY MAP FIGURE 1 PLAT OF THREADGILL CAVALLA LIBERTY GARDENS Liberty Gi3rdens t ) l I I I / / / /-; / .. ---1--~ //// /,/ I /// .- // / // ~// /// / ./ / / /· // / . / //1/____ r:,/ // / ..---: --r / ,,. -·-,,-, _.-I j / I • // D:'ISTING I~~ (oot BRIDGE II I;!·. I --... ; I ( / / ---:------------_..c / / / .1 i ' A 1 · Secondary Type 3 Stream ! I / --'/ ·-- / 1 .,._ ··, I \ " \ \ \ ' ' \ ' \ t;;. -~-; ~ ! I I I \ I I ._,_,_,...,,""'"",_ .. .,...,,,,,,.,~ ......... ==~ ';_,;;,;.-,,1'"'."sr..l-.J,fc •. L..,,-.<'M'~.'/:'".''H;c;;> •i),:i':t,'.' V L7.T'lf' ,.<:)'!'.\A.i\Mi!f!-'>: .'l'.3i>~•~•O-'' ::.:_\f_j." ~~s~..,,-..... · -· ·· .---, ~<o,. !'~!~~~f,,.~01 '.1~1['.~~ft~1; 1~k;/j~r~f~~. ;~~~.~r~;~. :~ <;1r!f.~f.='~.:i'' ,·!~'9~~~~jl':'.1~!lf~~-1r~~(Fll1'~"------· ~--o::_~ < N00'23'36"E 491.17' / );1'.'0?§1'~_:_:-·'. :~~-~25'trufler 0 • ffi2ND AVE'SE (CR=DAR AVE} J .... ,· /;-)_ /~<~<-=-:: ::·~--~:.=--:: _ _:-_ :_ _ · · --~ / ---_L --------..L ---_-: 7-::-0·----_:.:~ --:r= · -· -----="-"r;;:~....ce:·:-.:-:c=~:.._:~ .... "'-;_"f=c-%-,~~c:-.c__~~.::.=-~;:·'-"11-~Too-~.-=--'"-'"·,.._,..:: l . )' 7' -. ---· , · -25' Butter --- : 11 ~ --\-,--------r-------- ' ~ : ! \ \ I \ L \ Smith Property DATE: 04/30/07 12:51pm DiVG NA.ME: G: \project\Cllents\armour\KBS-162nd Ave_Cowlla_ Threodglll\pelrie162_001.d'ffg I i ..J J \~ Primary Type 3 Sire I I I I I I l ,•' .. --.:::-1\.-J ---.... 0 60 120 Seale in Feel Rich Lea Crest r __ ----- FIGURE 2: SITE PLAN 162nd Avenue SE Extension King County, Washington / Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 ® Mitigation Reserves Program Fee-In-Lieu Worksheet DOES Permit# Multiple King County Date 5/10//2007 Preoared bv: Chad Armour, LLC PLANT MATERIALS• Type Unit Price Unit Quantity Descriotion Cost PLANTS: Potted, 4' dtame1e,, medium $5.00 Each 198.00 $ 990,00 PLANTS: Con1ainer. 1 gallon, medium soil $11.51 Each 198.00 $ 2.2n.oo PLANTS: Con1ainer, 2 gallon, medium soil $20.00 Each 199.0 $ 3,980.00 PLANTS: Container, 5 gallon, medium soil $36.00 Each $ . PLANTS: Seeding, by hand $0.50 SY 806.0 7,250 sf $ 403.00 PLANTS: Sll)s (willow, red-0sier) $2.00 Each $ . PLANTS: Stakes (wiUow) $2.00 Each $ . '"All costs include inrulllation I TOTAL $ 7,650.00 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unit Price Unit Cost Compost, vegetable, delivered and spread $37.88 CY 39.0 3 ft rad around ea olant; 3 in dee[ $ 1,477.32 Decompacting tilVhardpan, medium, to 6' deplh $1.57 CY $ Decompaciing rnVhar~an, medium, to 12' depth $1.57 CY $ . Fertilize, slow release tablets, 30gm/lree $3.21 Each $ . Hydmseeding $0.51 SY 806.0 7,250 sf $ 411.06 Labor, genera! (landscaping) $25.00 HR $ . Labor, general (conslruc1ion) $37.0 HR 16.0 14,500 sf {0.33 ac) $ 592.00 Labor: Consufant supervising $55.nr HR 10.0 14,500 sf (0.33 ac) $ 550.00 Labor; Consuftanl, on-srte re-Oesign $95.00 HR $ . Rental of decompacling machinery & operator $70.65 HR $ . Sand, coarse buffder's, dehveredand spread $42.06 CY $ Staking material (set per tree) $7.00 Each $ . Surveying, line & grade $250.0 HR $ . Surveyflg, topographical $250.0 HR 8.00 $ 2,000.00 Wa1ering, 1' of water. 50' soaker hose $3.62 MSF $ . Irrigation -temporary $3,000.1) Acre $ . Irrigation -buried $4,500.0 Acre 0.33 $ 1,485.00 Hling topsoi, tlsk harrow, :ZOhp trac1or, 4'.6' deep $1.02 SY $ . TOTAL $ 6,515.38 HABITAT STRUCTURES• ITEMS Unit Cost Unit Cost Fascines (<Mllow) $ 2.00 Each $ . Logs, (cedar), vJ root wads, 16'-24' diam., 30' long $1,000.00 Each 3.00 $ 3,000.00 Logs (cedar) wto root wads, 16'-24" ciam, 30' $400.00 Each 8.00 $ 3,200.00 Logs, 'No root wads, 16' -24' diam, 30' long $245.0( Each $ . Logs w/ root wads, 16'-24' dam., 30' Jong $460.0( Each $ . Rocks, one-man $60.00 Each $ Rocks, two-man $120.0( Each $ Root wads $163.0 Each $ . Spawning gravel, type A $22.00 CY $ Weir-log $1,500/ll Each $ . Weir -adjustable $2,000.0C Each $ . Woody debris. large $163.0C Each $ Snags-anchored $400.0C Each 15.00 $ 6,000.00 Snags -on srte $50.00 Each $ . Snags -imported $800.0C Each $ . • All costs include delivery 70TAL $ 12,200.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backfill and Compaction-embankment $ 4.89 CY $ - Crushed surfacing, 1 1/4' minus $30.0C: CY $ - Drtching $7.0 CY $ - Excavation, bulk $4.0C CY $ - Fence, s111 $1.61 LF 120.00 14,500 sf (0.33 ac) $ 192.00 Jute Mesh $1.26 SY $ - Mulch, by hand, straw, 2' deep $1.2 SY $ - Mulch, by hand. wood chips, 2' deep $3.25 SY $ - Mulch, by machine, straw, 1' deep $0.32 SY $ - Piping, temporary, CPP. 6' $9.3 LF $ - Piping, lemporary, CPP. 8' $14.(J( LF $ - Piping, temporary, CPP, 12' $18.<> LF $ - Plastic covering, fifnm 1h ick. sandbagged $2.0 SY $ - Rip Rap, machine placed, slopes $33.9 CY $ - Rock Constr. Entrance 1OO'x15'x1' $3,000.00 Each $ - Rock Constr. Entrance SO'x15'x1' $1,500.00 Each 0.66 14,500 sf (0.33 ac) $ 990.00 Sediment pond riser assembly $1,695.11 Each $ - Sediment trap, 5' high berm $15.57 LF $ - Sediment trap, 5' high berm wlsp~lway incl. riprap $59.Sl LF $ - Sodding, 1' deep, level ground $5.24 SY $ - Sodding, 1' deep, sk:lped ground $6.41 SY $ - Straw bales, place and remove $600.rn TON $ - Hau~ng and disposal $20.0C CY $ - Topso~. delivered and spread $35.73 CY $ - I TOTAL $ 1,182.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain ~nk, 6' high $1B.m LF $ - Fencing, chain link, corner posts $111.1, Each $ - Fencing, chain hnk, gate $277.6 Each $ - Fencing. sp/i1 rail, 3' high {2-rarl) $10.54 LF 120.0C 14,500 sf (0.33 ac) $ 1,264.80 Fencing, temporary (NGPE) $1.2( LF $ - Signs, sensitive area boundary $2.51 Each 1.00 $ 2.50 I TOTAL $ 1,267.30 OTHER ITEMS MAINTENANCE AND MONTIORING Maintenance and Monrtoring Inspection. annual Main1enance and Monttorrng lnspect1on, final LAND COSTS $ LONG TERM SITE MANAGEMENT $ MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS Percentage of Construction Cost Unit (Construction Cost Subtotal) TOTAL NOTE: Projects with multiple permit requirements may be required to ha\'e longer monitoring and maintenance terms. This will be evaluated on a case-by- case basis for development applications. Monitoring and marntance ranges may be assessed anywhere from 5 to 10 years. EACH EACH 4 ·00 $144.90/hr TOTAL $ 28,814.68 $ 40,340.55 4,320.00 2,880.00 $ 362.25 $ 579.60 $ 8,141.85 Unit Cost Unii Quantity Description Cost 56,000.00 Acre 0.333 $ 18,648.00 Unit Cost Unit Quantity 85.00 Acre 1 Number of years 20 $ 1,700.00 -, -----r------- Total $97,645.08 CHAD ARMOUR, LLC May 16, 2007 Mr. Curtis Schuster KBS Develot;iment Corporation 12320 NE 8 Street, Suite 100 Bellevue, Washington 98005 Subject: Conceptual Wetland Mitigation Plan Cavalla Preliminary Plat King County, Washington Dear Mr. Schuster: 6500 126th Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com The following plan presents our approach to mitigating for unavoidable impacts to the buffer of a Category Ill wetland. PROPOSED DEVELOPMENT PLAN KBS Development Corporation (Proponent) proposes to construct 34 single-family homes on the 9.4-acre Cavalla site (Figure 1 ). To do so, it will be necessary to construct a new road (162"d Avenue SE). The road will impact a total of 887 square feet (sf) of Category Ill wetland buffer (Table 1 and Figure 2). We understand that the planned development is subject to the King County (County) Critical Areas regulations. We also understand that the Proponent proposes to make up for unavoidable impacts to the buffer using the Mitigation Reserves Program. CONCEPTUAL MITIGATION PLAN The plan is to: • Fill a portion of the wetland buffer; and • Pay the County a fee to create a 887 sf wetland buffer off of the site. EXISTING CONDITIONS According to 8-12 Wetland Consulting (2004) a wetland is dominated by immature red alder (A/nus rubra) trees, salmonberry (Rubus spectabilis) shrubs, and lady fern (Athyrium fi/ix-femina) is located off of the site near the southwest corner of the same. Based on our functional assessment, the wetland functions as a Category Ill wetland (Attachment A). The buffer extends into the proposed 162nd Avenue SE right-of-way. Assuming that the provisions of KKC 21A.24.325A3b apply, constructing the road will unavoidably impact a total of 887 sf of wetland buffer. :;,::~:: ::: fl,e eq,Wal,ot"' to oohaa~ a d,grad~~!;; ~® covering 887sf. \JU.,,, ,1\;\. \\ 1 MAIN FILE COPY ~ C o.o.E,S, C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 1/,. ~ 05/16/07 Cavalla Mitigation Plan King County, Washington ' based on a drawing prepared by B-12 areas' • Assumes a 50 ft buffer (exercise the buffer reduction option) Off-Site Buffer Enhancement We assume that: • It will be necessary to purchase urban land; KBS Development • A total of 12 trees and 24 shrubs will be installed in a degraded buffer at a rate of 0,041 plants/sf (Table 2); • A mixture of native herbaceous plant species will be broadcast seeded and hydroseeded on the degraded buffer; • 1 snag and 1 log will be installed in the degraded buffer; and • Compost will be added around each of the installed plants in a circle 3 ft in diameter and 3 inches (in) deep, and the site will be irrigated by way of a permanent irrigation system (Attachment B). MONITORING The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for monitoring the off-site buffer for at least three years following installation. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for monitoring associated with the proposed buffer fill and subsequent mitigation efforts. MAINTENANCE The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for maintenance of the off-site buffer during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for maintenance associated with the proposed buffer fill and subsequent mitigation efforts. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Annour, LLC 2 05/16/07 Cavalla Mitigation Plan King County, Washington KBS Development Table 2 -Plant and Habitat Amenit Installation Guide' 1 '887 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve ' total average density is 0.041 plants/sf CONTINGENCY PLAN The Proponent has included costs in the Mitigation Reserves Program "Fee-In-Lieu Worksheet" to allow for a contingency plan should deficiencies in the off-site buffer be discovered during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for contingency measures associated with the proposed buffer fill and subsequent mitigation efforts. SCHEDULE The Proponent anticipates paying the "Fee-In-Lieu" at the first available opportunity following the receipt of the necessary approvals from the County. We understand that this may be after Preliminary approval and prior to construction. LIMITATIONS Work for this project was perfonrned, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of KBS Development Corporation and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this mitigation plan is the responsibility of the permitting authority. Accordingly, the mitigation plan developed for this plat should be reviewed by the C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 3 05/16/07 Cavalla Mitigation Plan King County, Washington KBS Development appropriate permitting authority prior to committing to detailed planning and design activities. Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC ~A~ Chad Armour Principal Attachments: Figure 1 -Vicinity Map Figure 2 -Site Plan Attachment A -Wetland Rating Form -Western Washington Attachment B -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County DOES C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 4 05/16/07 FIGURES ON TRAFFIC CONSULTANTS ~/;:.: t';;.-J?;f}', p.<r [ ;:-; .. ~'":' 1!..o /\-1--'f-: tJf:• --:·-c t::,,e:: VICINITY MAP FIGURE 1 PLAT OF THREADGILL CAVALLA LIBERTY GARDENS ~ 1---~.------j $ ~' 31 lJ11 ·, ·, -30 ii l : ' i' 11-,-,,, _Tn_A_.C-,-.p-,-----c.J ' ' -,I ·. . . . . ' ' '· ,, ,· \ ' -' ' I IHAGi' ·A: ' STOW.A .PQNf> Buffer Reduciion Area ,,. / (887 SF) ~~-··. '\ 50' \ ~ Wetland ' ·, ./"" : Buffer • ~ I I I / / / I .•. , \ i I I N ' FIGURE 2: SITE PLAN KBS-Cavalla Site King County, Washington ' . ?Ji '·, ?9 ' / ' I I I I I I !1 ' 22 '' I I t'N-1CF, ' I ~3CObCCG I~ I ' ,, ,, I/ ' i" ·f' ~/\c. ~_L--------"----J V . •.. ' . (I Cavalla ,'/ ', ?!! ~ l.'1AC.' 'ti ('Ail.'( • .. .. l . ' , i ', ' ' . f6 . .. ::-.--. ~-.'RAC/' 'if' IHAC1 X' ~ B 9 ',_, ,,, ,"',-.:. P~'lCf:t'd \<157~() 0'45 • (H-10f'O.'~~:J Pl.Ai OF-111-lFffl'l' G.A"IXNE -u: ' ,.~4PCC3~i e;,::.,, /, l?i;c,:.,_ . v' r-'< ,0 ; . / "' ,, ;g ' ' I ' " -~ ' . _-; ' ' ' ' / ' 'J ' " ' Liberty Gardens 0 100 Scale in Feet Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 OAlE: 05/16/07 10:12om OWG NAM[: G:\pro~ct\OM:nb\orn,o1,1r\l(8S-t62nd Ave_Covallo_Th,eod9ill\Co"811o02.dw,q I• l g ~ '.c ATTACHMENT A Wetland Rating Form W ctland name or number WETLAND RA TING FORM -WESTERN WASHINGTON Version 2 -Updated July 2006 to increase accuracy and reproducibility among users Name of wetland (if known): Date of site visit: _:j}!:__</JI) :::;- Rated by a,, i Ar ,..,,..,_r Trained by Ecology? Yes_No /oate of training, __ _ SEC:J_ij_ TWNSHP: 2-JJ,}RNGE: $f.-Is S([/R in Appendix D? Yes /No_ Map of wetland unit: Figure__ Estimated size __ _ SUMMARY OF RATING Category based on FUNCJIONS provided by wetland I_ II_ III_/_ I IV_ Category I = Score >=70 Category II = Score 51-69 Category III= Score 30-50 Category IV= Score < 30 Score for Water Quality Functions Score for Hydrologic Functions Score for Habitat Functions TOTAL score for Functions Category based on SPECIAL CHARA)ITERISTICS of wetland I_ II_ Does not Apply_/_ Final Category (,h_, , .. "'"'"'" ~"''"' from ,hw,) I i1 Summary of basic information about the wetland unit Estuarine Natural Herita e Wetland Bo Mature Forest Old Growth Forest Coastal La oon Interdunal None of the above Wetland Rating Form -western Washington version 2 Flats Freshwater Tidal Check if unit has multiple HGM classes resent August 2004 Wetland name or number Does the wetland unit being rated meet any of the criteria below? If you answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. SP!. Has the wetland unit been documented as a habitat for any Federally listed Threatened or Endangered animal or plant species (TIE species)? For the purposes of this rating system, "documented" means the wetland is on the a ro riate state or federal database. SP2. Has the wetland unit been documented as habitat for any State listed Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note: Wetlands with State listed plant species are cate orized as Cate o I Natural Herita e Wetlands see . 19 of data form . SP3. Does the wetland unit contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part o(the data sheet you will need to determine the Hydrogeomorphic Class of the wetland being rated The hydrogeomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. Wetland Rating Form -western Washington version 2 2 August 2004 Wetland name or number Classification of Wetland Units in Western Washington \ --~ ,--.. T ---, T: r , ----,--~.-~-_•.-:-~':;:-",,. ~~-~;.. _, _ ---.. _ _ _ _ 1 ' ' • -• • • 1 , , , , • ~< ''I' S ' ' •:_ ' :I 11 ' , ' i' I " ' ( '1• r ' a ' I < l : ' ' ' ' I ' . ' ' ' I -' -' ' -. "'--~-----------~-~~ .... ~-'------------------~---------·-___ , ----·"'' ' "--~--- 1. ~water levels in the entire unit usually controlled by tides (i.e. except during floods)? ~go to 2 YES-the wetland class is Tidal Fringe If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES-Freshwater Tidal Fringe NO-Saltwater Tidal Fringe (Estuarine) If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. !fit is Saltwater Tidal Fringe it is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (seep. ) . . 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. ~dwater and surface water runoff are NOT sources of water to the unit. CJ,', go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both of the following criteria? _The vegetated part of the wetland is on the shores of a body of permanent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; C'r--:-::At least 30% of the open water area is deeper than 6.6 ft (2 m)? ~goto 4 YES -The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the e&ire wetland unit meet all of the following criteria? ~The wetland is on a slope (slope can be very gradual), __ /The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. lt may flow subsurface, as sheetflow, or in a swale without / distinct banks. _/_ 1The water leaves the wetland without being impounded? NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <Jft ~and less than 1 foot deep). NO -go to 5 C?' The wetland class is Slope Wetland Rating Fonn -western Washington version 2 3 August 2004 Wetland name or number 5. Does the entire wetland unit meet all of the following criteria? __ The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river __ The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with water when the river is ol flooding. go to 6 YES -The wetland class is Riverine 6. entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means thal any outlet, if present, is higher than the interior oflhe wet/~. NO -go to 7 ~The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO -go to 8 YES -The wetland class is Depression al 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM clases. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DJFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. Depressional + Riverine along stream within boundary De ressional + Lake-frin e Salt Water Tidal Fringe and any other class of freshwater wetland Depressional De ressional Treat as ESTUARINE under wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating Fonn -western Washington version 2 4 August 2004 Wetland name or number D D D 1. Does the wetland unit have the potential to improve water quality? D I.I Characteristics of surface water flows out of the wetland: Unit is a depression with no surface water leaving it {no outlet) points=-3 Unit has an intennittently flowing, OR highly constricted pennanently flowing outlet points~ 2 Unit has an unconstricted, or slightly constricted, surface outlet {permanently flowing) points= I Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a man-made ditch points= 1 (If ditch is not permanently flowing treat unit as "intermittently flowing") Provide· ·hgto or,gt,awlrr S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (use NRCS definitions) YES NO points~ 4 oints ~ 0 ¢ D 1.3 Characteristics of persistent vegetation (emergent, shrub, and/or forest Cowardin class) Itigur:e·_·. _ D D Wetland has persistent, ungrazed, vegetation>~ 95% of area points -5 Wetland has persistent, ungrazed, vegetation>~ 1/2 of area points= 3 Wetland has persistent, ungrazed vegetation>= 1/10 of area points= I Wetland has persistent, ungrazed vegetation <1/10 of area points= 0 M'<! Offilllwaroih ve f!tation-cilassas D 1.4 Characteristics of seasonal ponding or inundation. This is the area of the wetland unit that is ponded for at least 2 months, but dries out sometime during the year. Do not count the area that is permanently ponded. Estimate area as the average condition 5 out of JO yrs. Area seasonally ponded is> Y, total area of wetland Area seasonally ponded is> Y. total area of wetland Area seasonally ponded is< Y. total area of wetland --:::,.:, D Total for D l Add the points in the boxes above I ..5 I ~-+------------------------------------~----D D D 2. Does the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the following conditions provide the sources of pollutants. A unit may have pollutants coming from several sources, but any single source would qualify as opportunity. -Grazing in the wetland or within 150 ft -Untreated stonnwater discharges to wetland 7 Tilled fields or orchards within I 50 ft of wetland A stream or culvert discharges into wetland that drains developed areas, residential areas, / farmed fields, roads, or clear-cut logging ..Y.... Residential) urban areas, golf courses are within 150 ft of wetland Wetland is fed by groundwater high in phosphorus or nitrogen -Other _______________ _ YES NO multi lier is I Multiply the score from DI by D2 Add score to table on . 1 Wetland Rating Fonn -western Washington version 2 5 August 2004 (seep. 44) multiplier JO \Vt:tland name or number D D D D 3. Does the wetland unit have the potential to reduce flooding and erosion? D 3.1 Characteristics of surface water flows out of the wetland unit Unit is a depression with no surface water leaving it (no outlet) points= 4 Unit has an intennittently flowing, OR highly constricted permanently flowing outlet points= 2 Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a manMmade ditch points = I (lj ditch is not permanently flowing treat unit as "intermiltently flowing") Unit has an unconstricted or sli htl constricted, surface outlet ( ermanentl oints = 0 D 3.2 Depth of storage during wet periods Estimate the height of ponding above the bottom of the outlet. For units with no outlet · measure from the surface of permanent water or deepest part (if dry). Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 The wetland is a "headwater" wetland" points= 5 Marks of ponding between 2 fl to < 3 fl from surface or bottom of outlet points = 5 Marks are at least 0.5 fl to < 2 fl from surface or bottom of outlet points= 3 Unit is flat (yes to Q. 2 or Q. 7 on key) but has small depressions on the surface that trap points= I oints = 0 D 3.3 Contribution of wetland unit to storage in the watershed Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself The area of the bas in is less than IO times the area of unit The area of the bas in is IO to I 00 times the area of the unit The area of the basin is more than I 00 times the are a of the unit points= 5 points= 3 points= 0 Entire unit is in the FLATS class oints = 5 1-----"'==="--"========------------------'==-"---l.----D Total for D 3 Add the poinls in /he boxes above I '6 !--+-------------------------------------+----D D 4. Does the wetland unit have the opportunity to reduce flooding and erosion? Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a structure such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater in areas where damaging groundwater flooding does not occur. Note which of the following indicators of opportunity apply. ~etland is in a headwater of a river or stream that has flooding problems -Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface runoff water that might otherwise flow into a river or stream that has flooding problems ther ________________ _ multi lier is 2 NO multi lier is I D TOTAL -Hydrologic Functions Multiply the score from D 3 by D 4 Wetland Rating F onn -western Washington version 2 6 Add score to table on p. 1 August 2004 (seep. 49) multiplier Z- Pages 7 through 12 are not applicable Wetland name or number H I. Does the wetland unit have the potential to provide habitat for many species? H I. I Vegetation structure (seep. 72) Check the types of vegetation classes present (as defined by Cowardin)-Size threshold for each class is 'l4 acre or more than I 0% of the area if unit is smaller than 2.5 acres. __ Aquatic bed ___ Emergent plants __ Scrub/shrub (areas where shrubs have >30% cover) __ Forested (areas where trees have >30% cover) If the,;(mit has a forested class check if --11":The forested class has 3 out of5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the forested polygon Add the number of vegetation structures that qualify. ff you have: Map. of Clly,,att1iii,ve.~tation ·cl.asses H 1.2. Hydroperiods (seep. 73) 4 structures or more 3 structures 2 structures structure points= 4 points= 2 points = I oints = 0 Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than I 0% of the wetland or !1, acre to count. (see text for descriptions of hydroperiods) __ Pennanently flooded or inundated 4 or more types present __ Seasonally flooded or inundated 3 types present ___j')ccasionally flooded or inundated 2 types present __ / S, aturated only I type present _____/Pennanently flowing stream or river in, or adjacent to, the wetland __ / Seasonally flowing stream in, or adjacent to, the wetland points= 3 points= 2 point= I points= 0 __ Lake-fringe wetland = 2 points __ Freshwater tidal wetland= 2 points Map of hydroperiods H 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least IO ft2 • (different patches of the same species can be combined to meet the size threshold) You do not have to name the species. Do not include Eurasian Milfoil, reed canarygrass, purple /oosestrife, Canadian Thistle If you counted: > 19 species List species below if you want to: 5 -19 species < 5 species points= 2 points= I points= 0 flgµre._ I I Wetland Rating F onn -western Washington version 2 13 Total for page~ August 2004 \Vetland name or number H 1.4. Interspersion of habitats (seep. 76) ~-gii,e _._ Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H 1.1 ), or the classes and unvegetated areas ( can include open water or mudflats) is high, medium, low, or none. None -0 points Low -1 point Moderate -2 points ~ [riparian braided channels] High -3 points NOTE: If you have four or more classes or three vegetation classes and open water the ratin is alwa s "hi h". Use. mc1 .of Cawc1rdin ve l<ili.om:l!lsses H 1.5. Special Habitat Features: (seep. 77) Check the habitat features that are present in the wetland The number of checks is the ;; number of points you put into the next column. ____i_Iprge, downed, woody debris within the wetland (>4in. diameter and 6 fi long). _/_~Stt,anding snags (diameter at the bottom> 4 inches) in the wetland __ Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (10m) __ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet turned grey/brown) __ At least 1,/4 acre of thin-stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated.(structures for egg-laying by amphibians) __ Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated in early printings of the manual on page 78 is an error. r-----------------------------------~----H I. TOTAL Score -potential for providing habitat ~ 1 '--------------...:.A:::d:::d...:.th:.:;e::..;s::..:c:::co:..:re:::s..t.:..;;o:.:;m.:..H:.:..:..l ._:;l"-' .:.;Hc:.1.:::.2:,,., .:.;Hc:.1.:.:.30.., .:.;Hc:.1:..:.40.., .:.;H_:;l.:.:. 5'-'-'-J -----Comments Wetland Rating Form -western Washington version 2 14 August 2004 Wetland name or number H 2. Does the wetland unit have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Choose the description that best represents condition of buffer of wetland unit. The highest scoring criterion that applies to the wetland is to be used in the rating See text for definition of "undisturbed." 100 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed part of buffer. (relatively undisturbed also means no-grazing, no landscaping, no daily human use) Points= 5 -~Om (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > / ;~% circumference. Points = 4 -50 m (170ft) of relatively undisturbed vegetated areas. rocky areas, or open water >95% circumference. Points= 4 I 00 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 25% circumference, . Points = 3 50 m ( 170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference. Points = 3 If buffer does not meet any of the criteria above No paved areas (except paved trails) or buildings within 25 m (80ft) of wetland> 95% circumference. Light to moderate grazing, or lawns are OK. Points= 2 No paved areas or buildings within 50m of wetland for >50% circumference. Light to moderate grazing, or lawns are OK. Points= 2 Heavy grazing in buffer. Points = 1 Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g. tilled fields, paving, basalt bedrock extend to edge of wetland Points= 0. Buffer does not meet any of the criteria above. Points= l Aeriat -.hofo'sho.win . ,ff!!r:s H 2.2 Corridors and Connections (seep. 81) H 2.2.1 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor ( either riparian or upland) that is at least 150 ft wide, has at least 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dams in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corrid~r. . YES= 4 points (ga to H 2.3) NO go to H 2.2.2 H 2.2.2 Is the wetland part of a relatively undisturbed an roken vegetated corridor ( either riparian or upland) that is at least 50ft wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake-fringe wetland, if it does not have an undisturbed corridor as in the questio ov ? YE points (go to H 2.3) NO= H 2.2.3 H 2.2.3 ls t e wetland: within 5 mi (8km) of a brackish or salt water estuary OR within 3 mi of a large field or pasture (>40 acres) OR within I mi of a lake greater than 20 acres? YES= I oint NO= 0 oints z_ Total for page (c; Wetland Rating Form-western Washington version 2 15 August 2004 Wetland name or number H 2.3 Near or adjacent to other priority habitats listed bv WDFW (seep. 82) Which of the following priority habitats are within 330ft (IOOm) of the wetland unit? NOTE: the nee/ions do not have to be relatively undisturbed. se are DFW definitions. Check with your local DFW biologist if there are any questions. Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. __ Aspen Stands: Pure or mixed stands of aspen greater than 0.8 ha (2 acres). __ Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. __ Old-growth forests: (Old-growth west of Cascade crest) Stands of at least 2 tree species, forming a multi-layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre)> 81 cm (32 in) dbh or> 200 years of age. __ Mature forests: Stands with average diameters exceeding 53 cm (21 in) dbh; crown cover may be less that 100%; crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old- growth; 80 -200 years old west of the Cascade crest. __ Prairies: Relatively undisturbed areas (as indicated by dominance of native plants) where grasses and/or forbs form the natural climax plant community. __ Talus: Homogenous areas of rock rubble ranging in average size 0. 15 -2.0 m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. __ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages __ Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component of the stand is 25%. __ Urban Natural Open Space: A priority species resides within or is adjacent to the open space and uses it for breeding and/or regular feeding; and/or the open space functions as a corridor connecting other priority habitats, especially those that would otherwise be isolated; and/or the open space is an isolated remnant of natural habitat larger than 4 ha (10 acres) and is surrounded by urban development. __ Estuary/Estuary-like: Deepwater tidal habitats and adjacent tidal wetlands, usually semi- enclosed by land but with open, partly obstructed or sporadic access to the open ocean, and in which ocean water is at least occasionally diluted by freshwater runoff from the land. The salinity may be periodically increased above that of the open ocean by evaporation. Along some low-energy coastlines there is appreciable dilution of sea water. Estuarine habitat extends upstream and landward to where ocean-derived salts measure less than 0.5ppt. during the period of average annual low flow. Includes both estuaries and lagoons. Marine/Estuarine Shorelines: Shorelines include the intertidal and subtidal zones of beaches, and may also include the backshore and adjacent components of the terrestrial landscape (e.g., cliffs, snags, mature trees, dunes, meadows) that are important to shoreline associated fish and wildlife and that contribute to shoreline function (e.g., sand/rock/log recruitment, nutrient contribution, erosion control). If wetland has 3 or more priority habitats = 4 points If wetland has 2 priority habitats= 3 points If wetland has I priority habitat= I point No habitats= 0 points Note: All vegetated wetlands are by definition a priority habitat but are not included in this list. Nearbv wetlands are addressed in question H 2. 4! Wetland Rating Form -western Washington version 2 16 August 2004 \Vetland name or number H 2.4 Wetland Landscape (choose the one descnption of the landscape around the wetland that best fits) (seep. 84) There are at least 3 other wetlands within V2 mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points= 5 The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake-fringe wetlands within 1,1; mile points= 5 There are at least 3 other wetlands within V, mile, BUT the connections between them are disturbed points= 3 The wetland is Lake-fringe on a lake with disturbance and there are 3 other lake-fringe wetland within V, mile points= 3 There is at least I wetland within V, mile. points= 2 There are no wetlands within 1h mile. points= 0 H 2. TOTAL Score -opportunity for providing habitat Add the scores from H2.l,H2.2, H2.3, H2.4 TOT AL for H I from page 14 Total Score for Habitat Functions -add the points for H l, H 2 and record the result on Wetland Rating Form -western Washington version 2 17 n. I August 2004 -3 ----- I Jc) I ------0 ----- j~ Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. SC 1.0 Estuarine wetlands (seep. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? -The dominant water regime is tidal, -Vegetated, and -With a salinity greater than 0.5 ppt. YES= Go to SC I.I NO_/ SC I.I Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? YES = Cate o I NO o to SC 1.2 SC 1.2 Is the wetland unit at least 1 acre in size and meets at least two of the following three conditions? YES = Category I NO = Category II -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. If the non-native Spartina spp. are the only species that cover more than 10% of the wetland, then the wetland should be given a dual rating (l/11). The area of Spartina would be rated a Category II while the relatively undisturbed upper marsh with native species would be a Category I. Do not, however, exclude the area of Spartina in· determining the size threshold of I acre. -At least% of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Wetland Rating Fonn-western Washington version 2 18 August 2004 Cat. I Cat. I Cat. II Dual rating 1/11 Wetland name or number SC 2.0 Natural Heritage Wetlands (seep. 87) Natural Heritage wetlands have been identified by the Washington Natural Heritage Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2.1 Is the wetland unit being rated in a Sectionffownship/Range that contains a Natural Heritage wetland? (f:is question 1s used to screen out most 5/tes before you need to contac;/",,~HPIDNR) Sff/R information from Appendix D _ or accessed from WNHP/DNR web site _ YES __ -contact WNHP/DNR (seep. 79) and go to SC 2.2 NO SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as or as a site with state threatened or endangered plant specieso/ YES~ Category I NO .,/ not a Heritage Wetland O,,.•,. •e . ,·· ' ' SC 3.0 Bogs (seep. 87) Does the wetland unit ( or any part of the unit) meet both the criteria for soi ls and vegetation in bogs? Use the key below to identify if the wetland is a bog. If you answer yes you will still need to rate the wetland based on its functions. I. Does the unit have organic soil horizons (i.e. layers of organic soil), either peats or mucks, that compose 16 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes - go to Q. 3 No -go to Q. 2 2. Does the unit have organic soils, either peats or mucks that are less than 16 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? Yes -go to Q. 3 No -ls not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? Yes-Is a bog for purpose of rating No -go to Q. 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. !. Is the unit forested(> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine, WITH any of the species (or combination of species) on the bog species plant list in ~;1" 3 as a significant component ofthe ground cover(> 30% coverage of/._lotal shrub/herbaceous cover)? 2. YES = Category I No_ Is not a bog for purpose ofrating Wetland Rating Form -western Washington version 2 19 August 2004 Cat. I Cat. I Wetland name or number .C.i"?··s··, ;.~ ' .. _., ,,.a .. , . ,--·-· SC 4.0 Forested Wetlands (seep. 90) Does the wetland unit have at least I acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats? If you answer yes you will still need to rate the wetland based on its functions. -Old-growth forests: (west of Cascade crest) Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height (dbh) of32 inches (81 cm) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. -Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80 -200 years old OR have average diameters (dbh) exceeding 21 inches (53cm); crown cover may be less that l 00%; decay, decadence, numbers of snags, and quantity oflarge downed material is generally less than that found in old-growth. L. YES -Category I NO not a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (seep. 91) Does the wetland meet all of the following criteria ofa wetland in a coastal lagoon? -The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks -The lagoon in which the wetland is located contains surface water that is saline or brackish(> 0.5 ppt) during ~os /of the year in at least a portion of the lagoon (needs to be measured r the bottom) YES= Go to SC 5.1 NO_· not a wetland in a coastal lagoon SC 5.1 Does the wetland meets all of the following three conditions? -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). -At least% of the landward edge of the wetland has a I 00 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland is larger than l/10 acre (4350 square feet) YES = Category I NO = Category II Wetland Rating Form -western Washington version 2 20 August 2004 ... Cat. I Cat. I Cat. II Wetland name or number SC 6.0 Interdunal Wetlands (seep. 93) ls the wetland unit west of the 1889 line (also cazle the Western Boundary of Upland Ownership or WBUO)? YES -go to SC 6.1 NO_:__ not an interdunal wetland for rating If you answer yes you will still need to rate the wetland based on its functions. In practical terms that means the following geographic areas: • Long Beach Peninsula-lands west of SR I 03 • Gray land-Westport-lands west of SR I 05 • Ocean Shores-Copalis-lands west of SR 115 and SR I 09 SC 6.1 Is the wetland one acre or larger, or is it in a mosaic of wetlands that is once acre or larger? YES = Category II NO -go to SC 6.2 SC 6.2 Is the unit between O.l and I acre, or is it in a mosaic of wetlands that is between 0.1 and 1 acre? YES = Category III r= -~ .:.~· 1• r "' ., ',' -, •• ,' ,,~·'. ' .-.,•, --" j : / I ', , , 1 • , ,' / ' _ , • t f ' ' , . . . '....._~;, _,_\, • I, :___ -'-' ' ,~, '' I~ _ __::_ --'_}_,~~, ,, ___ .!_\~~-~~!.CJ~'-'..=.,~-.,_~::....,_"""-=--'-'-'-'~ Wetland Rating Form-western Washington version 2 21 August 2004 Cat. II Cat. III ATTACHMENT B Mitigation Reserve Program Fee-In-Lieu Worksheets ® Mitigation Reserves Program Fee-In-Lieu Worksheet Cavalla DOES Permit# King County Date 5/10/2007 Preoared bv: Chad Armour, LLC PLANT MATERIALS' Type Unit Price Unit Quantity Description Cost PLANTS Potted, 4' diame1er, medium $5.00 Each 12.0 $ 60.00 PLANTS: Container, 1 gallon, medium srnl $11.5( Each 12.0 $ 138.00 PLANTS: Con1ainer, 2 gailon, medium sod $20.00 Each 12.0 $ 240.00 PLANTS Container, 5 gallon, medium soil $36.00 Each $ PLANTS· Seeding, by hand $0.5( SY 49.00 444 sf $ 24.50 PLANTS Slips (willow, red-osier) $2.0C Each $ . PLANTS Stakes (willow) $2.00 Each $ . • All costs include installation TOTAL $ 462.50 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unrt: Price Unit Cost Compost. vegetable. delivered and spread $37.88 CY 3.00 3 ft rad around ea plant; 3 in dee~ $ 113.64 Oecompacting tilVhardpan, medium, lo 6' depth $1.57 CY $ . Decompacting tilVhar~an, medium, lo 12' deplh $1.57 CY $ . Fermize, stow release tablets, 30gmltree $3.21 Each $ Hydraseeding $0.51 SY 49.00 444 sf $ 24.99 Labor, general (landscap111g) $25.0 HR $ . Labor, general (construct:on) $37.U1 HR 16.0 887 sf (0.02 ac) $ 592.00 Labor: ConsuKant, supervising $55.00 HR 10.0 887 sf (0.02 ac) $ 550.00 Labor: ConsuHant, on-site re-design $95.0 HR $ . Rental of decompacting machinery & operator $70.6 HR $ . Sand, coarse builder's, delrvered and spread $42.06 CY $ . Slaking material (set per tree) $7.00 Each 12.0( $ 84.00 Surveying, Ii/le & grade $250.0 HR $ . Surveying, topographical $250.0 HR 8.00 $ 2,000.00 Watering, 1' of water, 50' soaker hose $3.62 MSF $ . Irrigation -temporary $3,000.0 Acre $ . /rrigalion -buried $4,500.UC. Acre 0.02 $ 90.00 Tilling topsol, dsk harrow, 20hp lractoc, 4' .ei" deep $1.02 SY $ . TOTAL $ 3,464.63 HABIT AT STRUCTURES' ITEMS Unit Cost Unit Cost Fascines ('Mllow) $ 2.00 Each $ . Logs, (cedar), vi root wads, 15"-24' dam_, 30' long $1,000.00 Each 1.00 $ 1,000.00 Logs (cedar) wo root wads, 16'-24" dam .. 30' $400.00 Each $ . logs, w/oroot wads, 16'-24" dam, 30'1ong $245.0( Each $ . Logs wf root wads, 16'-24' dam., 30' long $460.0C Each $ Rocks, one-man $60.00 Each $ Rocks, two-man $120.0 Each $ Roo1 wads $163.0C Each $ . Spawning gravel, type A $22.U1 CY $ . Weir-log $1,500.0( Each $ Weir -adjustable $2,000.01 Each $ Woody debris, large $163.0( Each $ . Snags -anchored $400.0( Each 1.00 $ 400.00 Snags -on site $50.00 Each $ . Snags -imported $800.01 Each $ . • All cosl:s inclucie deliveiy TOTAL $ 1,400.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backlill and Compaction-embankment $ 4.89 CY $ Crushed surfacing, 1 114' minus $30.00 CY $ . Ditching $7.03 CY $ . Excavalion. bulk $4.00 CY $ Fence, silt $1.60 LF 30.00 887 sf (0.02 ac) $ 48.00 Jule M11sh $1.26 SY $ . Mulch, by hand, straw, 2' deep $1.27 SY $ Mulch, by hand, wood chips, 2' deep $3.25 SY $ . Mulch, by machine, s1raw, 1' deep $0.32 SY $ Piping, temporary, CPP, 6' $9.30 LF $ . Piping, temporary, CPP, 6' $14.00 LF $ . Piping, temporary, CPP, 12" $18.00 LF $ . Plastic covering, 6mm lhick. sandbagged $2.00 SY $ . RP Rap, machine placed, slopes $33.98 CY $ Rock Conslr Entrance 100'x15'x1' $3,000.00 Each $ . Rock Conslr Entrance 50'x15':x1' $1,500.00 Each 0.33 887 sf (0.02 ac) $ 495.00 Sediment pond riser assembly $1,695.11 Each $ . Sedimen1 trap, 5' high berm $15.5, LF $ . Sediment rap, 5' high berm w/spillway ind. riprap $59.6' LF $ . Sodding, 1'deep, levelground $5.2 SY $ . Sodding, 1' deep, sklped ground $6.48 SY $ . S1raw bales, place and remove $600.0 TON $ . Hauling and d~posal $20.00 CY $ . Tops oil. delivered and spread $35.73 CY $ . (TOTAL $ 543.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencincr. chain link, 6' high $16.B! LF $ Fencmg, cha1n link, comer posts $111.1, Each $ Fencing, chain lrnk, gate $277.6" Each $ . Fencing, spl~iail. 3' high (2-fail) $10.54 LF 30.00 887 sf (0.02 ac) $ 316.20 Fencing, temporary (NGPE) $1.2( LF $ Signs, sensrl1ve area boundary $2.5( Each 1.00 $ 2.50 (TOTAL $ 318.70 OTHER ITEMS MAINTENANCE AND MONTIORING Maintenance and Monformg Inspection. annual Mainlenancc and Monrtormg lnspec1ion, final LAND COSTS LONG TERM SITE MANAGEMENT MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS (Construction Cost Subtotal) Percentage of Construction Cost Unit $ $ TOTAL NOTE: Projects with multiple permit requirements may be required to have longer monitonng and maintenance terms. This will be evaluated on a case-by- case basis for development applications. Manitonng and maintance ranges may be assessed anywhere from 5 to 10 years. EACH EACH 4 ·00 $144.90/hr TOTAL "1' Unit Cost Unit Quantity Description 56.000.00 Acre 0.02 Unit Cost Unit Quantity Number of years 85.00 Acre 1 20 Total $ 6,178.83 Cost $ 5,560.95 2,160.00 2,880.00 $ 289.80 $ 579.60 $ 5,909.40 'mZf!tb."· ·<F/:CSf'2";{~\:_;,t : \ Cost $ 1,120.00 $ 1,700.00 $20,469.18 CHAD ARMOUR, LLC May 16, 2007 Mr. Curtis Schuster KBS DeveloJ;>ment Corporation 12320 NE 8 Street, Suite 100 Bellevue, Washington 98005 Subject: Conceptual Wetland Mitigation Plan Cavalla Preliminary Plat King County, Washington Dear Mr. Schuster: 6500 1261 " Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax} chad@chadarmour.com The following plan presents our approach to mitigating for unavoidable impacts to the buffer of a Category Ill wetland. PROPOSED DEVELOPMENT PLAN KBS Development Corporation (Proponent) proposes to construct 34 single-family homes on the 9.4-acre Cavalla site (Figure 1). To do so, it will be necessary to construct a new road (162nd Avenue SE). The road will impact a total of 887 square feet (sf) of Category Ill wetland buffer (Table 1 and Figure 2). We understand that the planned development is subject to the King County (County) Critical Areas regulations. We also understand that the Proponent proposes to make up for unavoidable impacts to the buffer using the Mitigation Reserves Program. CONCEPTUAL MITIGATION PLAN The plan is to: • Fill a portion of the wetland buffer; and • Pay the County a fee to create a 887 sf wetland buffer off of the site. EXISTING CONDITIONS According to 8-12 Wetland Consulting (2004) a wetland is dominated by immature red alder (A/nus rubra) trees, salmonberry (Rubus spectabilis) shrubs, and lady fern (Athyrium filix-femina) is located off of the site near the southwest corner of the same. Based on our functional assessment, the wetland functions as a Category Ill wetland (Attachment A). The buffer extends into the proposed _162nd Avenue SE right-of-way. Assuming that the provisions of KKC 21A.24.325A3b apply, constructing the road will unavoidably impact a total of 887 sf of wetland buffer. CONSTRUCTION PLAN ~-© ~ ~ 1 g® The plan is to pay the County the equivalent fee to enhance a degrad -site buffer '2.0tfl covering 887sf. J\j\. \11 MAIN FILE COPY ... c o.o.e..s. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC i's-05/16/07 Cavalla Mitigation Plan King County, Washington a based on a drawing prepared by B-12 areas' 0 Assumes a 50 ft buffer (exercise the buffer reduction option) Off-Site Buffer Enhancement We assume that: • It will be necessary to purchase urban land; KBS Development • A total of 12 trees and 24 shrubs will be installed in a degraded buffer at a rate of 0.041 plants/sf (Table 2); • A mixture of native herbaceous plant species will be broadcast seeded and hydroseeded on the degraded buffer; • 1 snag and 1 log will be installed in the degraded buffer; and • Compost will be added around each of the installed plants in a circle 3 ft in diameter and 3 inches (in) deep, and the site will be irrigated by way of a permanent irrigation system (Attachment B). MONITORING The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for monitoring the off-site buffer for at least three years following installation. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for monitoring associated with the proposed buffer fill and subsequent mitigation efforts. MAINTENANCE The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for maintenance of the off-site buffer during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for maintenance associated with the proposed buffer fill and subsequent mitigation efforts. C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Annour, LLC 2 05/16/07 Cavalla Mitigation Plan King County, Washington KBS Development Installation Guide3 1 887 sf; to be made up off site according to KKC 21 A.24.137 Resource Mitigation Reserve ' total average density is 0.041 plants/sf CONTINGENCY PLAN The Proponent has included costs in the Mitigation Reserves Program "Fee-In-Lieu Worksheet" to allow for a contingency plan should deficiencies in the off-site buffer be discovered during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for contingency measures associated with the proposed buffer fill and subsequent mitigation efforts. SCHEDULE The Proponent anticipates paying the "Fee-In-Lieu" at the first available opportunity following the receipt of the necessary approvals from the County. We understand that this may be after Preliminary approval and prior to construction. LIMITATIONS Work for this project was performed, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of KBS Development Corporation and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this mitigation plan is the responsibility of the permitting authority. Accordingly, the mitigation plan developed for this plat should be reviewed by the C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 3 05/16/07 Cavalla Mitigation Plan King County, Washington KBS Development appropriate permitting authority prior to committing to detailed planning and design activities. Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC WA~ Chad Armour Principal Attachments: Figure 1 -Vicinity Map Figure 2 -Site Plan Attachment A -Wetland Rating Form -Western Washington Attachment B -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County ODES C:/Jobs/BCE/Cavalla/Fee In-Lieu Letter.doc Chad Armour, LLC 4 05/16/07 FIGURES DN TRAFFIC CONSULTANTS VICINITY lv1AP FIGURE 1 ' 1 PLAT OF THREADGILL CA VALLA LIBERTY GARDENS ··. !ii "' 1 VI !I! ~N'iCF! · t,306~(;C~I~ 11---------r I t '· 31 I ·. ) ti-,-~~----, 30 .1 I ' I I I . I I Is;, I ·N~C-. '3-:i 'A 1:a I 4:l'-''>Yk'l'.;1_, I I , L-5~:-·jJ~C . ' I . 26 25 ,; · •.. . . (? Cavalla. 79 Q\ · ~ m.,. er. ·.o: "It \t.:I'::::·· :::::::=:::::=;;;;;:=:===~::;;;;;;=~.,/, • ' I ··-;.;- ?. .. !HAOT ·A: -srom,i'Po/\'o ·. ' Buffer Reduction Area·· VV(8~7 SF) !?~. ·· ... '\ 50' 1 i,--Wetland ; Buffer \ \ I I I N J . ,. • FlflC:CI. ~ 145JS:, 0·45 :,\, • (FHOPOS!'-':) Pl/, I 0"-I IRf-'RlY GA'10CNS -i_[ ~ :..~,.t"C'.;J~i Liberty Gardens 0 "A:'lC::::_ , IC:,Df.5CCJHI; ?3 u friAC: 't:I P#ll( ' '6 . I I I !1 22 Tl·lACt'L . " ,, I I f'fc<;C.Fa ' I ~:3C65Gl'.r./'J I I ;'! !9 . . "' "iic,~;". -~--------, • J• - 1.i ·. !0 ··,,-.-------..--< . 100 I Scale in Feet FIGURE 2: SITE PLAN KBS-Cavalla Site King County, Washington DATE: 05/16/07 IO:t2am DWG NAME: G: \project\Oients\ormour\t<8S-l62nd Ave_Cova!lo_ Threodgill\CoYOllo02.dwg Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 • . ATTACHMENT A Wetland Rating Form Wetland name or number WETLAND RATING FORM -WESTERN WASHINGTON Version 2 • Updated July 2006 to increase accuracy and reproducibility among users Name of wetland (if known): Date of site visit: .:i}!:_<i)tJ S:- Rated by a6 J!_ Ar .... b>A( Trained by Ecology? Yes_No /nate of training, __ _ SEC: fl TWNSHP: 2.J t,/ RNGE: 5e,_ Is Srf/R in Appendix D? Yes /No_ Map of wetland unit: Figure__ Estimated size __ _ SUMMARY OF RATING Category based on FUNCJJONS provided by wetland I II III / IV -------- Category I = Score >=70 Category II = Score 51-69 Category III = Score 30-50 Category IV = Score < 30 Score for Water Quality Functions Score for Hydrologic Functions Score for Habitat Functions TOTAL score for Functions Category based on SPECIAL CHAR¢'ERISTICS of wetland I_ II_ Does not Apply_/ Fffial Category (cl>,_"' "h;g&~•" ra.,,., from ,,~,, I i1 Summary of basic information about the wetland unit Estuarine Natural Herita e Wetland Bo Mature Forest Old Growth Forest Coastal La oon Interdunal None of the above Wetland Rating Form -western Washington version 2 Flats Freshwater Tidal Check if unit has multiple HGM classes resent August 2004 Wetland name or number Does the wetland unit being rated meet any of the criteria below? If you answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. SP!. Has the wetland unit been documented as a habitat for any Federally listed Threatened or Endangered animal or plant species (TIE species)? For the purposes of this rating system, "documented" means the wetland is on the a ro riate state or federal database. SP2. Has the wetland unit been documented as habitat for any State listed Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note: Wetlands with State listed plant species are cate orized as Cate o I Natural Herita e Wetlands see . 19 of data form . SP3. Does the wetland unit contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its junctions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part ofthe data sheet you will need to determine the Hydrogeomorphic Class o{the wetland being rated. The hydrogeomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. Wetland Rating Form -western Washington version 2 2 August 2004 Wetland name or number Classification of Wetland Units in Western Washington 1. ~water levels in the entire unit usually controlled by tides (i.e. except during floods)? ~go to 2 YES -the wetland class is Tidal Fringe If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES -Freshwater Tidal Fringe NO -Saltwater Tidal Fringe (Estuarine) If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. Jfit is Saltwater Tidal Fringe it is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category J and II estuarine wetlands have changed (seep. ). 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. ~dwater and surface water runoff are NOT sources of water to the unit. 8, go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both of the following criteria? _The vegetated part of the wetland is on the shores of a body of permanent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; Cr-::::At least 30% of the open water area is deeper than 6.6 ft (2 m)? ~ i;o to 4 YES-The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the et\tire wetland unit meet all of the following criteria? __ylJThe wetland is on a slope (slope can be very gradual), __ ./The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without /distinct banks. _/_ 1The water leaves the wetland without being impounded? NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3fi ~and less than I foot deep). NO -go to 5 L,E?° The wetland class is Slope Wetland Rating Form -western Washington version 2 3 August 2004 Wetland name or number 5. Does the entire wetland unit meet all of the following criteria? __ The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river __ The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with water when the river is ot flooding. go to 6 YES -The wetland class is Riverine 6. entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means that any outlet, if present, is higher than the interior of the wetl'J':!!::\, NO -go to 7 ~ The wetland class is Depression al 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO -go to 8 YES -The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM clases. For example, seeps at the base ofa slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. Depressi onal + Riverine along stream within boundary De ressional + Lake-frin e Salt Water Tidal Fringe and any other class of freshwater wetland De ressional Treat as ESTUARINE under wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating Form -western Washington version 2 4 August 2004 Wetland name or number D D D D D 1. Does the wetland unit have the potential to improve water quality? DI .I Characteristics of surface water flows out of the wetland: Unit is a depression with no surface water leaving it (no outlet) points= 3 Unit has an intermittently flowing, OR highly constricted permanently flowing outlet points = 2 Unit has an unconstricted, or slightly constricted, surface outlet (permanently flowing) points = I Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a man-made ditch points = 1 (ff ditch is not permanently flowing treat unit as "intermittently flowing") Pr0vide it\!lto ondr'!I\Vit:l · S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (use NRCS definitions) YES NO points= 4 oints = 0 D 1.3 Characteristics of persistent vegetation (emergent, shrub, and/or forest Cowardin class) Wetland has persistent, ungrazed, vegetation>= 95% of area points = 5 Wetland has persistent, ungrazed, vegetation>= 112 of area points= 3 Wetland has persistent, ungrazed vegetation>= 1/10 of area points= I Wetland has persistent, ungrazed vegetation <I/IO of area points= 0 M\'I ;of:•Qlll!llatdin ve i,tation·classes DI .4 Characteristics of seasonal ponding or inundation. This is the area of the wetland unit that is ponded for at least 2 months, but dries out sometime during the year. Do not count the area that is permanently ponded Estimate area as the average condition 5 out of /0 yrs. Area seasonally ponded is > Y. total area of wetland Area seasonally ponded is> Y. total area of wetland Area seasonally ponded is< Y. total area of wetland ¢ ii'i!Jiire_.·. _ ¢ D Total for D 1 Add the points in the boxes above I -7 I ~-~------------------------------------~----D D D 2. Does the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater down gradient from the wetland. Note which of the following conditions provide the sources of pollutants. A unit may have pollutants coming from several sources, but any single source would qualify as opportunity. -Grazing in the wetland or within 150 ft -Untreated stormwater discharges to wetland 7 Tilled fields or orchards within 150 ft of wetland A stream or culvert discharges into wetland that drains developed areas, residential areas, _j farmed fields, roads, or clear-cut logging Residential, urban areas, golf courses are within 150 ft of wetland Wetland is fed by groundwater high in phosphorus or nitrogen -Other ______________ _ YES NO multi lier is I Multiply the score from DI by D2 Add score to table on . 1 Wetland Rating Form -western Washington version 2 5 August 2004 (seep. 44) multiplier /0 Wetland name or number D D D D 3. Does the wetland unit have the potential to reduce flooding and erosion? D 3.1 Characteristics of surface water flows out of the wetland unit Unit is a depression with no surface water leaving it (no outlet) points= 4 Unit has ar intermittently flowing, OR highly constricted permanently flowing outlet points ~ 2 Unit is a "flat" depression (Q. 7 on key}, or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a man•made ditch points= I (if ditch is not permanently flowing treat unit a<; "intermittently flowing'') Unit has an unconstricted, or sli htl constricted, surface outlet ermanentl oints = 0 D 3.2 Depth of storage during wet periods Estimate the height of ponding above the bottom of the outlet. For units with no outlet measure from the surface of permanent water or deepest part (if dry). Marks of ponding are 3 ft or more above the surface or bottom of outlet points -7 The wetland is a "headwater" wetland" points -5 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points -5 Marks are at least 0.5 ft to< 2 ft from surface or bottom of outlet points -3 Unit is flat (yes to Q. 2 or Q. 7 on key) but has small depressions on the surface that trap points -I oints -0 D 3.3 Contribution of wetland unit to storage in the watershed Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself The area of the bas in is less than IO times the area of unit The area of the basin is IO to 100 times the area of the unit points~ 5 points~ 3 The area of the basin is more than 100 times the area of the unit points~ 0 Entire unit is in the FLA TS class oints ~ 5 f----"'==="--"'--":....:C"'-'---"'=-"--==--------------------"==-"--~----D Total for D 3 Add the points in the boxes above <Z 1----1-~~~~~~~~~~~~~~~~~~---4---~- (seep. 49) D D D 4. Does the wetland unit have the opportunity to reduce flooding and erosion? Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a structure such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater in areas where damaging groundwater flooding does not occur. Note which of the following indicators of opportunity apply. ~etland is in a headwater ofa river or stream that has flooding problems -Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface runoff water that might otherwise flow into a river or stream that has flooding problems multi lier is 2 NO multi lier is 1 TOTAL -Hydrologic Functions Multiply the score from D 3 by D 4 Add score to table on p. 1 Wetland Rating Form -western Washington version 2 6 August 2004 multiplier Pages 7 through 12 are not applicable Wetland name or number H 1. Does the wetland unit have the potential to provide habitat for many species? H 1.1 Vegetation structure (seep. 72) Check the types of vegetation classes present (as defined by Cowardin)-Size threshold for each class is~ acre or more than 10% of the area if unit is smaller than 2.5 acres. __ Aquatic bed __ Emergent plants __ Scrub/shrub (areas where shrubs have >30% cover) __ Forested (areas where trees have >30% cover) Ifthe,/mit has a forested class check if __LThe forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the forested polygon Add the number of vegetation structures that qualify. If you have: Map. of Covv~n:liii vegfitl\ion -ti asses H 1.2. Hydroperiods (seep. 73) 4 structures or more 3 structures 2 structures I structure points~ 4 points~ 2 points ~ I oints = 0 Check the types of water regimes (hydroperiods) present within the wetland The water regime has to cover more than 10% of the wetland or ~ acre to count. (see text for descriptions ofhydroperiods) __ Pennanently flooded or inundated 4 or more types present __ Seasonally flooded or inundated 3 types present ___J'.)ccasionally flooded or inundated 2 types present __ / S, aturated only I type present __________fiennanently flowing stream or river in, or adjacent to, the wetland __ / Seasonally flowing stream in, or adjacent to, the wetland points~ 3 points= 2 point~ I points~ 0 __ Lake-fringe wetland = 2 points __ Freshwater tidal wetland= 2 points Map of hydroperiods H 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least IO ft 2 • (different patches of the same species can be combined to meet the size threshold} You do not have to name the species. Do not include Eurasian Mi!foil, reed canarygrass, purple loosestrife, Canadian Thistle lfyou counted: > 19 species List species below if you wan/lo: 5 -19 species < 5 species points~ 2 points~ I points= 0 ~lg.ure_ Wetland Rating Form-western Washington version 2 13 Total for page~ August 2004 Wetland name or number H 1.4. Interspersion of habitats (seep. 76) ;i!Jtlte _ Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H I.I), or the classes and unvegetated areas (can include open water or mudflats) is high, medium, low, or none. None== 0 points Low~ 1 point Moderate ~ 2 points ~ [riparian braided channels] High ~ 3 points NOTE: If you have four or more classes or three vegetation classes and open water the ratin is alwa s "hi h". U~e ma ofC!i>Wardin.ve · l!lation cfa~ses H 1.5. Special Habitat Features: (seep. 77) Check the habitat features that are present in the wetland. The number of checks is the ;; number of points you put into the next column. __l_ljirge, downed, woody debris within the wetland (>4in. diameter and 6 ft long). __ /standing snags (diameter at the bottom> 4 inches) in the wetland __ Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (Im) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (!Om) __ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs ofrecent beaver activity are present (cut shrubs or trees that have not yet turned grey/brown) __ At least V. acre of thin-stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated. (structures for egg-laying by amphibians) __ Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated in early printings of the manual on page 78 is an error. r----------------~------~~----------~----H I. TOT AL Score -potential for providing habitat .__:;, I Add the scores om HJ.I, HI.2, Hl.3, Hl.4, Hl.5 J ~--------------~====~=~~=========~=~...._ ___ _ Comments Wetland Rating Form -western Washington version 2 14 August 2004 Wetland name or number H 2. Does the wetland unit have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Choose the description that best represents condition of buffer of wetland unit. The highest scoring criterion that applies to the wetland is to be used in the rating. See text for definition of "undisturbed. " 100 m (330ft) ofrelatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed part of buffer. (relatively undisturbed also means no-grazing, no landscaping, no daily human use) Points= 5 -~Om (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > /;~o/o circumference. Points= 4 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points= 4 I 00 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 25% circumference, . Points = 3 50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference. Points = 3 If buffer does not meet any of the criteria above No paved areas (except paved trails) or buildings within 25 m (80ft) of wetland> 95% circumference. Light to moderate grazing, or lawns are OK. Points= 2 No paved areas or buildings within 50m of wetland for >50% circumference. Light to moderate grazing, or lawns are OK. Points= 2 Heavy grazing in buffer. Points= I Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g. tilled fields, paving, basalt bedrock extend to edge of wetland Points =O. Buffer does not meet any of the criteria above. Points= I Aerial·. l:leto Showin J;Mf$tS H 2.2 Corridors and Connections (seep. 81) H 2.2.1 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 150 ft wide, has at least 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dams in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corridG2r. . YES= 4 points (go to H 2.3) NO go to H 2.2.2 H 2.2.2 Is the wetland part of a relatively undisturbed an n roken vegetated corridor ( either riparian or upland) that is at least 50ft wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake-fringe wetland, if it does not have an undisturbed corridor as in the questio~v ? YE points (go to H 2.3) NO= H 2.2.3 H 2.2.3 Is t e wetland: within 5 mi (8km) of a brackish or salt water estuary OR within 3 mi of a large field or pasture (>40 acres) OR within I mi of a lake greater than 20 acres? YES = l oint NO= 0 oints Wetland Rating Form-western Washington version 2 15 Total for page G August 2004 Wetland name or number H 2.3 Near or adjacent to other priority habitats listed bv WDFW (seep. 82) Which of the following priority habitats are within 330ft (l OOm) of the wetland unit? NOTE: the nections do not have to be relatively undisturbed. se are DFW definitions. Check with your local DFW biologist if there are any questions. Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. __ Aspen Stands: Pure or mixed stands of aspen greater than 0.8 ha (2 acres). __ Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. __ Old-growth forests: (Old-growth west of Cascade crest) Stands of at least 2 tree species, forming a multi-layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre)> 81 cm (32 in) dbh or> 200 years of age. __ Mature forests: Stands with average diameters exceeding 53 cm (2 I in) dbh; crown cover may be less that I 00%; crown cover may be less that I 00%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old- growth; 80 -200 years old west of the Cascade crest. __ Prairies: Relatively undisturbed areas (as indicated by dominance of native plants) where grasses and/or forbs form the natural climax plant community. __ Talus: Homogenous areas of rock rubble ranging in average size 0.15 -2.0 m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. __ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages __ Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component of the stand is 25%. -~Urban Natural Open Space: A priority species resides within or is adjacent to the open space and uses it for breeding and/or regular feeding; and/or the open space functions as a corridor connecting other priority habitats, especially those that would otherwise be isolated; and/or the open space is an isolated remnant of natural habitat larger than 4 ha (10 acres) and is surrounded by urban development. __ Estuary/Estuary-like: Deepwater tidal habitats and adjacent tidal wetlands, usually semi- enclosed by land but with open, partly obstructed or sporadic access to the open ocean, and in which ocean water is at least occasionally diluted by freshwater runoff from the land. The salinity may be periodically increased above that of the open ocean by evaporation. Along some low-energy coastlines there is appreciable dilution of sea water. Estuarine habitat extends upstream and landward to where ocean-derived salts measure less than 0.5ppt. during the period of average annual low flow. Includes both estuaries and lagoons. __ Marine/Estuarine Shorelines: Shorelines include the intertidal and subtidal zones of beaches, and may also include the backshore and adjacent components of the terrestrial landscape (e.g., cliffs, snags, mature trees, dunes, meadows) that are important to shoreline associated fish and wildlife and that contribute to shoreline function (e.g., sand/rock/log recruitment, nutrient contribution, erosion control). If wetland has 3 or more priority habitats= 4 points If wetland has 2 priority habitats= 3 points If wetland has I priority habitat= I point No habitats= 0 points Note: All vegetated wetlands are by definition a priority habitat but are not included in this list. Nearbv wetlands are addressed in auestion H 2.4) Wetland Rating Form -western Washington version 2 16 August 2004 Wetland name or number H 2.4 Wetland Landscape (choose the one description of the landscape around the wetland that best fits) (seep. 84) There are at least 3 other wetlands within l/2 mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points~ 5 The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake-fringe wetlands within '/, mile points~ 5 There are at least 3 other wetlands within 'I, mile, BUT the connections between them are disturbed points~ 3 The wetland is Lake-fringe on a lake with disturbance and there are 3 other lake-fringe wetland within '/, mile points~ 3 There is at least I wetland within Y, mile. points~ 2 Tilere are no wetlands within 1/2 mile. points~ 0 H 2. TOT AL Score -opportunity for providing habitat Add the scores from H2.1,H2.2, H2.3. H2.4 TOT AL for H I from page 14 Total Score for Habitat Fuuctious -add the points for H I, H 2 and record the result on Wetland Rating Form -western Washington version 2 17 p. I August 2004 3 ----- I /cJ I ------....'.:> -----,~ Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. ·~Mii,at~~i°::,~fW~L· SC 1.0 Estuarine wetlands (seep. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? -The dominant water regime is tidal, -Vegetated, and -With a salinity greater than 0.5 ppt. YES= Go to SC I.I NO_/ SC I.I Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? YES= Cate o I NO o to SC I .2 SC 1.2 Is the wetland unit at least I acre in size and meets at least two of the following three conditions? YES = Category I NO = Category II -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than I 0% cover of non-native plant species. If the non-native Spartina spp. are the only species that cover more than I 0% of the wetland, then the wetland should be given a dual rating (I/II). The area of Spartina would be rated a Category II while the relatively undisturbed upper marsh with native species would be a Category I. Do not, however, exclude the area ofSpartina in· determining the size threshold of I acre. -At least% of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Wetland Rating Form-western Washington version 2 18 August 2004 Cat. I Cat. I Cat. II Dual rating 1/11 Wetland name or number SC 2.0 Natural Heritage Wetlands (seep. 87) Natural Heritage wetlands have been identified by the Washington Natural Heritage Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2. I Is the wetland unit being rated in a Section/Township/Range that contains a Natural Heritage wetland? (Y:is questwn 1s used to screen out most sites before you need to contac:;r,.:1:HPIDNR) S(f/R information from Appendix D _ or accessed from WNHPIDNR web site _ YES __ -contact WNHP/DNR (seep. 79) and go to SC 2.2 NO SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as or as a site with state threatened or endangered plant speciesV YES~ Category I NO_,,/_ nncot a Heritage Wetland . " --. . SC 3.0 Bogs (seep. 87) Does the wetland unit (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below to identify if the wetland is a bog. If you answer yes you will still need to rate the wetland based on its Junctions. I. Does the unit have organic soil horizons (i.e. layers of organic soil), either peats or mucks, that compose I 6 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes - ~mQ.3 ~-~mQ.2 2. Does the unit have organic soils, either peats or mucks that are less than I 6 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? Yes -go to Q. 3 No -Is not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? Yes -ls a bog for purpose of rating No -go to Q. 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5. 0 and the "bog" plant species in Table 3 are present, the wetland is a bog. I. Is the unit forested(> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine, WITH any of the species (or combination of species) on the bog species plant list in ~:~J. 3 as a significant component of the ground cover(> 30% coverage of7_w1al shrub/herbaceous cover)? 2. YES = Category I No_ ls not a bog for purpose of rating Wetland Rating Form~ western Washington version 2 19 August 2004 Cat. I Cat. I Wetland name or number . ·-. --- SC 4.0 Forested Wetlands (seep. 90) Does the wetland unit have at least 1 acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats? If you answer yes you will still need to rate the wetland based on its functions. -Old-growth forests: (west of Cascade crest) Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height ( dbh) of 32 inches (81 cm) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. -Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80-200 years old OR have average diameters (dbh) exceeding 21 inches (53cm); crown cover may be Jess that I 00%; decay, decadence, numbers of snags, and quantity of large downed material is generally Jess than that found in old-growth. _L. YES = Category I NO not a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (seep. 91) Does the wetland meet all of the following criteria ofa wetland in a coastal lagoon? -The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, Jess frequently, rocks -The lagoon in which the wetland is located contains surface water that is saline or brackish(> 0.5 ppt) during~os of the year in at least a portion of the lagoon (needs to be measured n r the bottom) YES= Go to SC 5.1 NO_ not a wetland in a coastal lagoon SC 5.1 Does the wetland meets all of the following three conditions? -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has Jess than 20% cover of invasive plant species (see list of invasive species on p. 74). -At least 'I, of the landward edge of the wetland has a I 00 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland is larger than 1/10 acre (4350 square feet) YES = Category I NO = Category ll Wetland Rating Form -western Washington version 2 20 August 2004 . -, . '.: •. Cat. I Cat. I Cat. II Wetland name or number SC 6.0 Interdnnal Wetlands (seep. 93) Is the wetland unit west of the 1889 line (also cazle the Western Boundary of Upland Ownership or WBUO)? YES -go to SC 6.1 NO_:_ not an interdunal wetland for rating If you answer yes you will still need to rate the wetland based on its functions. In practical terms that means the following geographic areas: • Long Beach Peninsula-lands west of SR 103 • Grayland-Westport-lands west of SR I 05 • Ocean Shores-Copalis-lands west of SR 115 and SR 109 SC 6.1 ls the wetland one acre or larger, or is it in a mosaic of wetlands that is once acre or larger? YES = Category II NO -go to SC 6.2 SC 6.2 Is the unit between 0. I and I acre, or is it in a mosaic of wetlands that is between 0.1 and I acre? YES = Category III Wetland Rating Fonn -western Washington version 2 21 August 2004 Cat. II Cat. III ATTACHMENT B Mitigation Reserve Program Fee-In-Lieu Worksheets ® Mitigation Reserves Program Fee-In-Lieu Worksheet ODES Permit# Cavalla King County Date: 5/10/2007 Prenared bv; Chad Armour, LLC PLANT MATERIALS' Type Unit Price Unit Quantity Description Cost PLANTS: Potted, 4' d~melef, medium $5.00 Each 12.00 $ 60.00 PLANTS: Container, 1 gafon, medium soil $11.5f Each 12.00 $ 138.00 PLANTS: Conlainer, 2 galion, medium soil $20.0 Each 12.00 $ 240.00 PLANTS: Container. 5 gallon, medium soil $36.0 Each $ . PlANTS: Seeding, by hand $0.5 SY 49.00 444 sf $ 24.50 PLANTS: Sl~s (willow, red-osier) $2.0 Each $ . PLANTS: Stakes (willow) $2.00 Each $ . • All costs include installation TOTAL $ 462.50 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unit Price Unit Cost Compost, vegetable, de!i~ered and spread $37.8€ CY 3.00 3 ft rad around ea plant; 3 in dee~ $ 113.64 Decompaciing tilVhardoan, medium, 1o 6' depth $1.57 CY $ . Decompacting tWhardcan, medium, to 12' depth $1.57 CY $ . Fertilize, slow release tablets, 30gm/tree $3.21 Each $ . Hydroseeding $0.51 SY 49.0 444 sf $ 24.99 Labor, general (landscaping} $25.0 HR $ . Labor, general (cons1ruct~n) $37." HR 16.0C 887 sf (0.02 ac) $ 592.00 Labor: Consultant. supervising $55.0 HR 10.0C 887 sf (0.02 ac) $ 550.00 Labor: ConsuHant, on-s~e re-design $95.01 HR $ - Rental of decompac1ing machinery & operator $70.65 HR $ . Sand. coarse builder's, delivered and spread $42.0E CY $ - Stakiig material (set per tree) $7.00 Each 12.0 $ 84.00 SurveyinQ, line & grade $250.0! HR $ . Surveyino. topographical $250.0 HR 8.00 $ 2,000.00 Watering, 1' of water, 50' soaker hose $3.62 MSF $ . Irrigation -temporary $3,000.0 Acre $ . lmgalion -buried $4,500.0C Acre 0.02 $ 90.00 TIiing 1opsol, d<;k harrow, 20hp tratlOf, -4"-6'" deep $1.02 SY $ . TOTAL $ 3,464.63 HABITAT STRUCTURES' ITEMS Unit Cost Unit Cost Fascines ('willow) $ 2.00 Each $ . logs, {cedarf, W root wads, 16'-24' dam., 30' long $1,000.0( Each 1.00 $ 1,000.00 Logs (cedar\ 'No root wads, 16"-2-4" dam., 30' $400.0( Each $ . Logs, wlo root wads. 16"-24" dam.. 30' long $245.01 Each $ . logs w/ root wads, 16"-2-4" llam., 30' long $460.0C Each $ . Rocks, one-man $60.00 Each $ Rocks, two-man $120.0C Each $ Roo1 wads $163.0C Each $ Spawning gravel, type A $22.Ul CY $ . Weir-log $1,500.00 Each $ Weir -adjustable $2,000.0( Each $ . Woody debris, large $163.00 Each $ . Snags-anchored $400.0( Each 1.00 $ 400,00 Snags -on stte $50.00 Each $ . Snags -imported $800.0 Each $ . ' All costs include delivery I TOTAL $ 1,400.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backfill and Compaction-embankmen1 $ 4.89 CY $ Crushedsurtacing. 11/4'mim1s $30.00 CY $ - Drtching $7.03 CY $ - Excavation, bulk $4.00 CY $ Fence., sitt $1.60 LF 30.00 887 sf (0.02 ac) $ 48.00 Jute Mesh $1.26 SY $ - Mulch, by hand, straw, 2' deep $1.27 SY $ - Mulch, by hand, wood chips, 2' deep $3.25 SY $ - Mulch, by machine, siraw, 1' deep $0.32 SY $ - Piping, temporary, CPP, 6' $9.3( LF $ Piping, temporary, CPP, 8' $14.0 LF $ Piping, temporary, CPP, 12' $18.0C LF $ Plastic covering, 6mm thick, sandbagged $2.00 SY $ Rip Rap, machine placed, skipes $33.98 CY $ Rock Conslr. Entrance 100'x15'x1' $3,000.00 Each $ Rock Constr. Entrance 50'x15'x1' $1,500.00 Each 0.33 887 sf (0.02 ac:) $ 495.00 Sediment pond riser assembly $1,695.11 Each $ Sediment tap, 5' high berm $15.5 LF $ seamen! trap, 5' ro;Jh berm w/sp~lway ind. riprap $59.6{ LF $ Sodding, t' deep, level ground $5.24 SY $ Sodding, 1' deep, sloped ground $6.48 SY $ Straw bales, place and remove $600.0C TON $ - Hauhng af\d d~osal $20.0( CY $ T opso1l, delivered and spread $35.7 CY $ !TOTAL $ 543.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain link. 6' high $18.89 LF $ Fencing, cham link, comer posts $1 t 1.1 Each $ Fencing, cham link, gale $277.6 Each $ Fencing, spit rail, 3' high (2-rail) $10.54 LF 30.01 887 sf {0.02 ac) $ 316.20 Fencing, temporary {NGPE) $1.20 LF $ . Signs, seflsltive area boundary $2.50 Each 1.00 $ 2.50 I TOTAL $ 31B.70 OTHER ITEMS MAINTENANCE AND MONTIORING Maintenance and Monilormg Inspection, annual Maintenance and Monrlormg lnspec11on, final LAND COSTS LONG TERM SITE MANAGEMENT MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS Percentage of Construction Cost Unit (Construction Cost Subtotal) TOTAL NOTE: Projects with multiple permit requirements may be required to haye longer monitonng and maintenance terms. This will be evaluated on a case·by" case basis for development applications. Monitonng and maintance ranges may be assessed anywhere from S to 10 years. EACH z.oo $144.90/hr EACH 4 ·00 $144 901hr TOTAL Unit Cost Unit Description $ 56,000.00 Acre 0.02 $ 6,178.83 Cost $ 5,560.95 2,160.00 2,880.00 $ 289.80 $ 579.60 $ 5,909.40 Cost $ 1,120.00 Unit Cost Unit Quantity Number of years f--_c_c"-'"'-l-----"'--'--+~==+--------'----; $ $ Eill A= 1 ~ 1,100.00 Total $20,469.18 CHAD ARMOUR, LLC May 16, 2007 Mr. Dave Petrie 811 South 273rd Court De Moines, Washington 98198 6500 126th Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 (425) 643-3499 (fax) chad@chadarmour.com Subject: Conceptual Wetland Mitigation Plan (revised) Liberty Gardens Preliminary Plat (L04P0034) King County, Washington Dear Mr. Petrie: We revised our conceptual mitigation plan based on information provided to us by Mr. Nick Gillen in the meeting we had on February 28, 2007 and the fee-in-lieu spreadsheet on March 14, 2007. As you will recall, we chose the fee-in-lieu option to mitigate for unavoidable impacts to wetlands because the area available on the site for mitigation is the location of a mature forest. The following describes our approach in revising the conceptual mitigation plan including the estimated cost to construct a wetland off of the site. PROPOSED DEVELOPMENT PLAN Mr. Dave Petrie (Proponent) proposes to construct 37 single-family homes on the 8.95- acre Liberty Garden site (see Preliminary Plat of Liberty Gardens). To do so, it will be necessary to construct new roads and storm management facilities (see Preliminary Grading and Storm Drainage Plan of Liberty Gardens). The road will impact a total of 2,387 square feet (sf) of Class 2 wetland and 14,840 sf of buffer (Table 1 and Preliminary Plat of Liberty Gardens). It will also impact an intermittent stream that flows through one of the wetlands and across the site. We understand that the planned development is vested under the King County Sensitive Areas regulations. CONCEPTUAL MITIGATION PLAN The proposed mitigation plan is to: • • • • • • • Protect a portion of the wetland associated with the intermittent stream; Protect the intermittent stream; Protect the associated buffer; Fill a portion of two wetlands and associated buffer; Increase the width of buffer adjacent to wetland adjacent to the stream to make up for lost buffer; Enhance the buffer makeup areas; and / !:' ~@ @ @ ~ W @ID} Pay the County a fee to create a 7,161 sf wetland off of the si1'el. LJ JGL O 7. 2::J? L':'., K.C. DOE~ ....... C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 1 05/16/07 Chad Armour, LLC MAIN FILE COPY bt,f't:,tt,() I Liberty Garden Revised Mitigation Plan King County, Washington act and makeu areasa a based on Preliminary Grading Plan (revised) of Liberty Gardens • 961st + 1,426 sf ' to be made up according to KKC 21A.24.137 Resource Mitigation Reserve ' 8,379sf + 6,207sf+ 254sf EXISTING CONDITIONS Mr. Dave Petrie According to B-12 Wetland Consulting (2004) and our observations over the last several years, the upland forest is composed of an overstory of mature big-leaf maple (Acer macrophylfum), red alder (A/nus rubra), western red cedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesi1), and western hemlock (Tsuga heterophylla). The understory supports salmonberry (Rubus spectabilis), Indian plum (Oemleria cerasiformis), hazel nut (Cory/us comuta), sword fern (Po/ystichum munitum), salal (Gaultheria shallon), and bracken (Pteridium aquilinum). Wetland AIB (Southern Wetland) The southern wetland is a Class 2 wetland that consists of a narrow strip of forest adjacent to a Class 3 intermittent stream (B-12 Wetland Consulting, 2004). The wetland supports an overstory of red alder and black cottonwood (Popu/us balsamifera) trees. The understory supports salmonberry, lady fern (Athyrium filix-femina), and tall mannagrass (G/yceria e/ata). Wetland C (Northern Wetland) The northern wetland is a Class 2 wetland dominated by immature red alder trees, salmonberry shrubs, and lady fern (B-12 Wetland Consulting, 2004). Mature Trees In the Reduction and Makeup Areas As indicated on Table 2 and the Significant Tree Retention Plan of Liberty Gardens, 20 medium-to large-sized deciduous and conifer trees will be lost due to the proposed development. To offset this Joss, a total of 21 medium-to large-sized deciduous and conifer trees will be protected in buffer makeup areas. C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 2 Chad Armour, LLC 05116107 Liberty Garden Revised Mitigation Plan King County, Washington • see Significant Tree Retention Plan for details CONSTRUCTION PLAN Mr. Dave Petrie We developed this plan to mitigate for lost wetland and buffer area and functions by assuming that a 7,161 sf wetland will be created off of the site and 14,840 sf buffer will be enhanced on the site. We used the general guidance for completing fee-in-lieu worksheet for offsite mitigation construction costs (Attachment A) to determine the materials and labor to construct a wetland (King County, Undated). Table 3 illustrates the suggested plants and habitat amenities to be installed in the created wetland and enhanced buffer. Off-Site Wetland Creation We assume that: • It will be necessary to purchase urban land; • A total of 92 trees and 205 shrubs will be installed in the created wetland at a rate of 0.041 plants/sf (Table 3); • A mixture of native herbaceous plant species will be broadcast seeded on the wetland creation area; • 9 snags and 6 logs will be installed in the wetland creation area; and • It will take 4 hours to deconsolidate the soil, compost will be added around each of the installed plants in a circle 3 feet (ft) in diameter and 3 inches (in) deep, and the site will be irrigated by way of a permanent irrigation system (Attachment A). On-Site Buffer Enhancement In the buffer enhancement areas, we assume that machine encroachment will be limited to trackhoe excavators used to install snags and place logs. We assume that the crushed shrubs and herbs will recover. We also assume that: • A total of 38 western red cedar trees will be installed 20 ft on center to increase the density of conifer trees in the buffer make up areas; C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 3 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington Table 3 -Plant and Habitat Amenit Installation Guide western red cedar Thu·a /icata western red cedar Thu·a licata Total Trees black Lonicera twinber invo/ucrata clustered Rosa rose Pacific ninebark red-osier Camus do wood sto/onifera western craba le Ma/us fusca Total Shrubs Tellima randiflora Stachys coole i large-leaved Geum avens macro h I/um tall manna tufted Deschampsia hair rass ces itosa Oenanthe Sna s Los various 0.041 I/sf various 20 ft oc various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf various 0.041 I/sf seed broadcast seed broadcast seed broadcast seed broadcast seed broadcast 16" to 24" dbh; 30' Ion 16" to 24" dbh; 30' Ion Mr. Dave Petrie Quantit Total Wetland Buffer 92 92 0 38 0 38 130 92 38 41 41 0 41 41 0 41 41 0 41 41 0 41 41 0 205 0 X X X X X X X X X X 28 9 19 21 6 15 • 7,161 sf; to be made up off site according to KKC 21A.24.137 Resource Mitigation Reserve ' 15,004 sf; to be made up and enhanced on-site C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 4 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington Mr. Dave Petrie • It will not be necessary to install shrubs and herbs because a dense layer of shrubs and a robust assemblage of herbs are present in the buffer enhancement areas; • 19 snags and 15 Jogs will be installed; • The snags and logs will come from trees harvested on the site; • A signed split-rail fence will protect the Southern Wetland, the intermittent stream, and associated buffers. MONITORING The Proponent will monitor the on-site mitigation areas for at least three years following installation in the summer. The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for monitoring the off-site wetland for at least three years following installation. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for monitoring associated with the proposed wetland fill and subsequent mitigation efforts. MAINTENANCE The Proponent will maintain on-site mitigation area as follows: • Remove weeds for three years after installation. Weeds include non-native vegetation, particularly Himalayan blackberry, reed canarygrass, and evergreen blackberry; and • Replace trees that die during the 3-year monitoring program to maintain the minimum 80 percent survival rate. The Proponent has included costs in the Mitigation Reserves Program, Fee-In-Lieu Worksheet to allow for maintenance of the off-site wetland during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for maintenance associated with the proposed wetland fill and subsequent mitigation efforts. CONTINGENCY PLAN lfthere is difficulty achieving the performance standards on the site, the Proponent proposes to work with the County to develop a contingency plan. Contingency plans can include, but are not limited to: additional plant installation and plant substitutions of type, size, quantity, and location. Such a contingency plan shall be submitted to the County by December 1 '1 of any year when deficiencies are discovered. The Proponent has included costs in the Mitigation Reserves Program "Fee-In-Lieu Worksheet" to allow for a contingency plan should deficiencies in the off-site wetland be discovered during the three year monitoring program. The "fee-in-lieu" revenue that the County will receive in conjunction with this Proposal constitutes the full extent of the Proponent's responsibility for contingency measures associated with the proposed wetland fill and subsequent mitigation efforts. C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 5 Chad Armour, LLC 05/16/07 Liberty Garden Revised Mitigation Plan King County, Washington SCHEDULE Mr. Dave Petrie The Proponent anticipates executing this plan at the first available opportunity following the receipt of the necessary approvals from the County. Assuming construction occurs the summer of 2007, the first monitoring event will occur the following spring. The Proponent will submit a monitoring report as indicated previously. Maintenance will occur within four months following submission of the monitoring report. Subsequent monitoring, reporting, and maintenance will follow the same schedule during the subsequent years. LIMITATIONS Work for this project was performed, and this mitigation plan prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of Mr. Dave Petrie and his assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that wetland mitigation planning is an inexact science. Biological professionals may disagree on the nature and extent of mitigation plans. Final acceptance of this wetland mitigation plan is the responsibility of the permitting authority. Accordingly, the wetland mitigation plan developed for this plat should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. REFERENCES B-12 Wetland Consulting, Inc. 2004. Liberty Gardens Critical Areas Analysis Area Report & Conceptual Mitigation Plan, King County WA Prepared for Mr. Dave Petrie, 811 S. 273'd Ct., Des Moines, WA 98198. King County. Undated. Mitigation Reserves Program, Fee-In-Lieu Worksheet. C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 6 Chad Armour. LLC 05116107 Liberty Garden Revised Mitigation Plan King County, Washington Mr. Dave Petrie Any questions regarding our work and this plan, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC CUil~ Chad Armour Principal Attachments: Figure 1 -Vicinity Map Figure -Preliminary Plat Map of Liberty Gardens Figure -Preliminary Grading and Storm Drainage Plan of Liberty Gardens Figure -Significant Tree Retention Plan of Liberty Gardens Attachment A -Mitigation Reserves Program, Fee-In-Lieu Worksheet cc: Wayne Potter, Barghausen Consulting Engineers Nick Gillen, King County DOES C:/Jobs/BCE/Petrie/Fee In-Lieu Letter(revised).doc 7 Chad Armour, LLC 05/16/07 FIGURES ON TRAFFIC CONSULTANTS VI Cl f\J I TY M ,L\f::.i FIGURE 1 ·, , ... '.' . . .... , -- PLAT OF THREADGILL CA VALLA LIBERTY GARDENS ATTACHMENT A Mitigation Reserve Program Fee-In-Lieu Worksheets ® Mitigation Reserves Program Fee-In-Lieu Worksheet L04P0034 DOES Permit#· King County Date· 5/16/2007 Preoared bv: Chad Armour, LLC PLANT MATERIALS" Type Unit Price Unit Quantity Description Cost PLANTS: Polled, 4' diameter. medium $5.0 Each $ . PLANTS: Container, 1 gallon. medium srnl $11.5( Each 74.0 $ 851.00 PLANTS: Container, 2 gallon, medium soil $20.00 Each 74.00 $ 1,480.00 PLANTS Container. 5 gallon, medium soil $36.00 Each 74.00 $ 2,664.00 PLANTS Seeding, by hand $0.50 SY 795.00 7,161 sf $ 397.50 PLANTS Slips (willow, red-osier) $2.0( Each 74.00 $ 14B.OO PLANTS: Stakes (willow} $2.00 Each $ • All costs include installation JTOTAL $ 5,540.50 INSTALLATION COSTS ( LABOR, EQUIPMENT, & OVERHEAD) Type Unit Price Unit Cost Compost, vegetable, delivered and spread $37.88 CY 20.00 3 ft rad around ea plant: 3 in dee1 $ 757.60 Decompachng 1i1Vhar~an, medium, to 6' depih $1.57 CY 150.00 $ 235.50 Decompacimg t~Vhardpan, medium, to 12' depth $1.57 CY $ . Ferti~ze, slow release 1ablets. 30gm/lree $3.21 Each $ Hyctoseeding $0.51 SY 0.00 hand seeded $ Labor, general (landscapITTg) $25.00 HR $ labor, general (conslruct1on) $37.00 HR 16.0 7,161 sf (0.16 ac) $ 592.00 Labor: Consu~an1, supervising $55.0 HR 10.0 7,161 sf (0.16 ac) $ 550.00 Labor: Consultant ori.s~e re-Oesign $95.r> HR $ . Renlal of decompac1ing machinery & operator $70.65 HR 6.00 assumed $ 423.90 Sand, coarse builder's, delivered and spread $42.06 CY $ . Slaking malarial {se1 per tree) $7.00 Each 92.0 $ 644.00 Surveying, line & grade $250.0 HR $ . Surveying, topographical $250.01 HR 8.00 $ 2,000.00 Watering, 1' of waler, 50' soaker hose $3.62 MSF $ . Irrigation -temporary $3,000.0( Acre $ . Irrigation -buried $4,500.0 Acre 0.16 $ 720.00 Tillmg topsoi, cisk harrow, 20hp tractor, 4'-6' deep 795.00 7,161 sf: strip & stockpile topsoil $1.02 SY and then reapply $ 810.90 TOTAL $ 6,733.90 HABITAT STRUCTURES' ITEMS Unit Cost Unit Cost Fascines (wiUow) $ 2.00 Each $ . Logs, {cedar), w' root wads. 16' -24' Qam., JD' !ong $1,000.0 Each 3.00 $ 3,000.00 Logs (cedar) Wo rool wads. 16'-24' diam .. JO' $400.0C Each 3.00 $ 1,200.00 Logs, w/o rool-wads, 16' -24' diam., 30' long $245.0 Each $ logs w/ root wads. 16'-24' diam JO' long $460.0 Each $ Rocks, one-man $60.00 Each $ . Rocks, two-man $120.0( Each $ . Root wads $163.01 Each $ . Spawning gravel, type A $22.00 CY $ . Weir-log $1,500.01 Each $ . Weir -adjustable $2,000.0C Each $ Woody debris, large $163.01 Each $ Snags -anchored $400.00 Each 9.00 $ 3,600.00 Snags -on s~e $50.00 Each $ . Snags -imported $800.0C Each $ . • All co&S include deJr,ery TOTAL $ 7,800.00 EROSION CONTROL ITEMS Unit Cost Unit Cost Backfill and Compaciion-embankmenl $ 4.89 CY $ Crushed surfacing, 1 1/4' minus $30.00 CY $ Drtching $7.03 CY $ . Excavation, bulk $4.0 CY $ . Fence, sil1 $1.60 LF 85.00 $ 136.00 Jute Mesh $1.2 SY $ . Mulch, by hand, straw, 2' deep $1.2, SY $ . Mulch, by hand, wood chips, 2' deep $3.25 SY $ . Mulch, by machine, straw. 1' deep $0.32 SY $ . Piping, temporary, CPP, 6' $9.30 LF $ . Pipmg, temporary, CPP, 8' $14.00 LF $ . Piping, temporary, CPP, 12' $18.00 LF $ . Plastic covering, 6mm thick, sandbagged $2.0 SY $ . Rip Rap, machine placed, slopes $33.98 CY $ Rock Constr. Entrance 100'x15'x1' $3,000.00 Each $ . Rock Constr. Entrance 50'x15'x1' $1,500.00 Each 0.33 7,161 sf (0.16 ac) $ 495.00 Sediment pond riser assembly $1,695.11 Each $ Sediment trap, 5' h~h berm $15.57 LF $ . Secimenl trap, S' high berm wlspihwy incl. rip rap $59.6[ LF $ . Sodding, t' deep, level ground $5.2 SY $ Sodding, 1' deep, sloped ground $6.4! SY $ . Straw bales, place and remove $600.0! TON $ . Hauling and disposal $20.00 CY $ . Topsoil. delivered and spread $35.73 CY $ . ITDTAL $ 631.00 GENERAL ITEMS ITEMS Unit Cost Unit Cost Fencing, chain Unk, 6' high $18.89 LF $ . Fencing, chain hnk, corner posts $111.1, Each $ . Fencing, chain lrnk, gate $277.6 Each $ Fencing, sprn rail, 3' high (2-rnil) $10.54 LF 85.00 7,161 sf(0.16ac) $ 895.90 Fencing, temporary (NGPE) $1.20 LF $ . Signs, sens~ive area boundary $2.50 Each 1.00 $ 2.50 !TOTAL $ 898.40 OTHER ITEMS MAINTENANCE AND MONTIORING Maintenance and Monitoring Inspection, final LAND COSTS LONG TERM SITE MANAGEMENT MITIGATION RESERVES PROGRAM ADMINISTRATION COSTS Percentage of Construction Cost Unit (Construction Cost Subtotal) TOTAL NOTE: ProJects with multiple permit requirements may be required to have longer morntonng and maintenance terms. This will be evaluated on a ccise-by- case basis for development applications. Monitoring and maintance ranges may be assessed anywhere from 5 to 10 years. TOTAL Unit Cost Unit Quantity Description $ 56,000.00 Acre 0.16 South/Urban $ 21,60l,80 Cost $ l0,245.ll 2.700 00 3,600.00 724.50 $ 579.60 $ 7,604.10 Cost $ 8,960.00 Unit Cost Unit Quantity Number of years l-$-=8-5-.0~o+---A~,r~e--1---'=1 ='4-----2-0--'------l $ 1,700.00 Total $70,113.22 • • I I I I I I I I I I I I I I I (i1tiA.v ~ . ~ I Y' ~ l1J 'Z --n a· 0 1-~ ~" . < .. ~ "1 'to~ JyG ~N.G\~ PRELIMINARY TECHNICAL INFORMATION REPORT Proposed Plat of Cavalla East Side of 162nd Avenue S.E. South of S.E. 137th Place King County, Washington Prepared for: KBS Ill, LLC 12320 N.E. 8th Street, Suite 100 Bellevue, WA 98005 December 21, 2005 Our Job No. 11778 00 ~©~~W~[]) JAN 1 2 2006 K.C. D.D.E.S. leXPIRES 10/10/ lb Lot.ofooo) CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES r" 18215 72NDAVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 FAX k\v::) BRANCH OFFICES + OLYMPIA, WA + TEMECULA, CA M~ttliftf!°~A www.barghausen.com IA I I I I I I I I I I I I I I I I I f: i: 1.0 2.0 3.0 TABLE OF CONTENTS PROJECT OVERVIEW Figure l -Technical Information Report (TIR) Worksheet Figure 2 -Vicinity Map Figure 3 -Drainage Basins, Subbasins, and Site Characteristics Figure 4 -Soils Map CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of Core Requirements 2.2 Analysis of Special Requirement No. I OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrology C. Performance Standards D. Flow Control System E. Water Quality System 11778.005.doc (JPJ/tep] I I I I I I I I I I I I I I I I I I I 1.0 PROJECT OVERVIEW The proposed plat of Cavalla is approximately a 9.4-acre site located within a portion of the Southeast quarter of Section 14, Township 23 North, Range 5 East, Willamette Meridian, King County, Washington. More specifically, the site is located on the eastern side of 162nd Avenue S.E. and 200 feet south of S.E. 137th Place and is fairly rectangular in shape. The enclosed Figure 2 -Vicinity Map, depicts the approximate location of the proposed site. The existing topography is such that it is undeveloped and consists of forested areas over the entire site. The site tends to slope at an approximately grade of 8 percent in a north to southwesterly direction. There is one existing single-family residence located in the northwest corner of the project site. This residence will be demolished with the construction of this plat. The storm drainage facility is proposed to be located in the southwest comer of the project site such that the site will discharge in the same location it does under existing conditions. There are no wetlands located on this project site and road improvements are proposed for half-street widening of 162nd Avenue S.E. This is why the flow control calculations utilized 9.91 acres of development rather than 9.4 acres, since there are road improvements along the western property line of the site. The western boundary of the project site is formed by 162nd Avenue S.E. The plat of Liberty Lane forms the project site's northern boundary. Unplatted land, which may be a park area, forms the eastern boundary of the project site. There is a proposed development located south of the project site that will probably be developed concurrently with this project since it has been previously submitted to King County for plat approval. The proposal for this development is to subdivide the property into 34 separate lots with a separate tract for access to some of the lots, and another tract for storrnwater quality and a flow control facility. In addition, road improvements will be constructed throughout the project to provide access to the project's lots. Elevations on the site range from 480 along the northern property line down to 432 along the southern property line at the southwest comer of the project site. There is an approximate 5.4-acre upstream basin contributing runoff to the northern property line of the project site. This runoff is channeled along the perimeter of the property line of the site and discharges at the northwest comer of the site near a ditch onto the road improvements proposed for this development. This ditch will be collected by a catch basin and pipe conveyance system at the northwest comer of the site and routed, in a separate system bypassing the on-site pipe conveyance system, discharging to the detention pond. This upstream basin will be routed through the road improvements and will discharge further downstream, much as it does under existing conditions, at the southwest comer of the property site. 11778005.doc [JPJ/tep] I I I I I I I I I I I I I I I I I I I King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner KBS I!I, LLC Address 12320 N.E. 8th Street, Suite 100 Bellevue, WA 98005 Phone Project Engineer Ali Sadr, P.E. Company Barghausen Consulting Engineers, Inc. Address/Phone 18215 -72nd Avenue South Kent, WA 98032 I ( 425) 251-6222 Part3 TYPE OF PERMIT APPLICATION IZJ Subdtvision HPA D Short Subdfvision IZJ Grading D Commercial D Other Part 5 SITE COMMUNITY AND DRAtNAGE BASIN Community Renton Highlands Drainage Basin Cedar River Part6 SITE CHARACTERISTICS D River D Stream D Critical Stream Reach D Depressions/Swales D Lake D Steep Slopes Part2 PROJECT LOCATION AND'DESCRIPTION Project Name Proposed Plat of Cavalla Location Township 23 North Range 5 East Section 14 Part 4 OTHER REVIEWS AND PERMITS D DFWHPA D Shoreline Management D COE 404 D Rockery D DOE Dam Safety D Structural Vaults D FEMA Floodplain D Other D COE Wetlands D Floodplain D Wetlands D Seeps/Springs D High Groundwater Table D Groundwater Recharge D Other t 1778.005.doc [JPlhep] I I I I I I I I I I I I I I I I I I I Part 7 SOILS Soil Type Slopes Alderwood D Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE D D D D D Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION [8] Sedimentation Facilities 121 Stabilized Construction Entrance [8] Perimeter Runoff Control D Clearing and Grading Restrictions [8l Cover Practices C8J Construction Sequence D Other Part 10 SURFACE WATER SYSTEM D Grass Lined Channel D Tank 0 Pipe System D Vault D Open Channel D Energy Dissipater 121 Dry Pond D Wetland 121 Wet Pond D Stream Erosion Potential Erosive Velocities LIMITATION/SITE CONSTRAINT 0 [81 [81 0 D D D D D D D MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surface Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris Ensure Operation of Permanent Facilities Flag Limits of SAO and Open Space Preservation Areas Other-------------------' Infiltration Method of Analysis Depression KCRTS Flow Dispersal Compensation/Mitigation Waiver of Eliminated Site Storage Regional Detention Level 2 Flow Control Brief Description of System Operation Catch basin collection to oioe convevance to wet/detention pond then dispersed. Facility Related Site Limitations Reference Facility Limitation 11778.005.doc [JPJ/tep] I I I I I I I I I I I I I I I I l Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS D Cast in Pface Vault D Drainage Easement D Retaining Wall D Access Easement D Rockery> 4' High D Native Growth Protection Easement D Structural on Steep Slope 13] Tract D Other D Other Part 13 SIGNATURE OF PR0FESS10NAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. I 1778.005.doc [JPJ/tep] • I • I I I I I • I I I I I -J: ST ~/" ~.::, ST RENTON + Sf l6 ,, VICINITY MAP SOURCE: THE THOMAS GUIDE (USED BY PERMISSION') f'c• b wf !'; J ' ~I /0! » i" .~ ~ ::; I I :'l w ~ ~ "" ~ ~ 0 g NORTH " • ! ; ! -' ; I ! I' ;! -' '. -' -; -' ; ' . . -, •! 1: l! ~~! . ~~~ . if ,.· '" I j ... '.'['l -- i~ I! 11 I ( .. --• 11 ,1. ,, ,, ' • I . ,. ' ' I -•Ill -~ ·_ r _. ~ o· ~ ·-u i ·~ \, 11 ~I I ~;- i I~~~!.': r ~ .. I;;;. ;;;, g . 4 ~ij~i g. ! -,-·. I ! / I :IJ ,. \ " :=·"'I. - ~56 • 9 ffi,JO ! -~ ' i ......ill...! 8 4~2. b:J """' ~ ,.... I . GtiA.<, o..evo«1 _n_ I s...,,., 18215 72ND AVENUE SOUTH nm~~ KENT. WA 98032 ,.., ·= Ho~zont<,I (42~)251-6222 o,..,, .. ~ ...,IS._ ,·-~· -:' -(425)251-8782 FAX S?iHt (l'· ,,;i 0 • Ap~.D!Cll... \lortlc.11 . ' CML HIGlflEERlf/G, LAND Pl.ANNING, ,1, ""&<,.., ........ "'· SU~NG, E)NiRON'-IEHTAl. SERVlCES c,.,,. l.2LDI/Jl5 5 I .vq rn,:;1"' ~7~- :,,1,r;r~~-~,,, -- For. P·\ I :000,1 'r},'8'.p,o;;,,...;M,, \; > 118-~,,,, ,•w9 !k,r•/'·"'• 12/.',)/"j,h'~ , •·<B ,~a¥. • ~'ii) •-M~U ,._ • ., . ., ; 1I7J!J-o;•11'8 .,,._,!I lllJ-Ol.<fo,,-O,.tl p 118-r ~ ~ ~~j! •• i i . Tr 0 -,- 4~," C -,-rr-- ~ I .!;l_l_l ~-J ' ~se.1 14S~ _f L. .... @.,i g I <5a.os ~ill ~ '~ ~i~! . . j . ~~.~!. SJ.a..: 1 .. ::, ff i l • ~ -; ~ :~r r--, I r 1mr~ /1~ : ~ ~I '.1111··1' 1 [ 1 !f 1~ i , l,1 ' 8 . PYl ST~ ~ 14-t04 I P\A ELE'I • <4-59.20 \ No. I o..t• I~ ICkd. I "Pf!,, H...-1,olon KBS DEVELOPMENT CORP. 12320 N.E. 8TH STREET, STE. 100 BELLEVUE, WA 98005 lltle< PRELIMINARY ROAD AND PROFILES AND DRAINAGE PLAN FOR CAVALLA I • I I I I I I I I I I I I I I I I I ~15 ... ; . : r" l I I I I I L . f. r. I I I f ' I '. " .. " ' ' ' ~~ AgC Akf ---~ . : . ,., .. ?,>."i ;.?, j ·~ ... /l • I .. \ i AkF SOILS MAP NORTH I • 2.0 I I I I I I I ->r. CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of Core Requirements Core Requirement No. I: Discharge at the Natural Location. Response: This project site will discharge after flow control in the water quality pond at the same location it does under existing conditions. Core Requirement No. 2: Off-Site Analysis. Response: This project has prepared an off-site analysis that is located in Section 3.0 of this Preliminary Technical Information Report. Please refer to that document for the off-site analysis. Core Requirement No. 3: Flow Control. Response: This project will provide flow control in the form of a wet/detention pond located in the southwest comer of the project site discharging to the same location as it does under existing conditions. In addition, Flow Control BMPs will be applied to all lots by the developer and the contractor at the time of construction. For the initial sizing of the flow control pond prepared for this development, the flow control BMPs were not included in the calculations. Therefore, a pond larger than what will actually be required was determined for this project site. This is a conservative design. Core Requirement No. 4: Conveyance System. Response: The conveyance system for this project site will be sized according to the 2005 King County, Washington Surface Water Design Manual (KCSWDM). Since the project site is less than JO acres in size, the pipe conveyance system will be sized based on the Rational method as delineated in the 1990 KCSWDM utilizing an initial time of concentration of6.3 minutes and a Manning's "n" value of0.014. In addition, the 25-year precipitation will be utilized, which is a requirement of the 2005 KCSWDM. The 100-year event will be analyzed for overtopping as long as it does not impact any downstream development. Core Requirement No. 5: Temporary Erosion and Sediment Control. Response: This project site will follow the erosion and sediment control measures as delineated in Appendix D of the 2005 KCSWDM such that clearing limits will be specified, cover measures will be instituted, perimeter protection will be installed in the form of silt fences, a rock construction entrance will be installed, and the streets will be swept clean of sediment after construction at the end of each day. On-site sediment retention will be maintained in the form of a sediment pond. Surface water collection will be maintained by collecting runoff from the project site through temporary V-ditches and routing them to the sediment pond, sized according to Appendix D of the 2005 KCSWDM. Core Requirement No. 6: Maintenance and Operations. Response: This project will concur with all maintenance and operations requirements as delineated in the 2005 KCSWDM for projects of this nature. I 1778.005.doc fJPJ/tep] I • I • I I I I I I I I I I I I I I I 2.2 Core Requirement No. 7: Financial Guarantees and Liability. Response: This project will concur with all financial guarantees and liability requirements of the 2005 KCSWDM as delineated for projects of this nature. Core Requirement No. 8: Water Quality . Response: The Water Quality Menu followed for this project site requires that the Basic Water Quality Menu be followed for this development. One of the options of the Basic Water Quality Menu allows the provision of a wet pond. This project is proposing a wet pond located below the live storage in the wet/detention pond such that three times the mean annual storm will be provided as dead storage below the live storage in the wet/detention pond. Analysis of Special Requirement No. 1 Special Requirement No. I: Other Adopted Area-Specific Requirements. Response: To the best of our knowledge, the site is not located in an Other Adopted Area-Specific Requirement area; therefore, Special Requirement No. l does not apply. 11778.005.doc [JPJ/iepj I II I LEVEL 1 OFF-SITE DRAINAGE ANALYSIS Proposed Plat of Cavalla East Side of 162nd Avenue S.E. South of S.E. 137th Place King County, Washington Prepared for: KBS Ill, LLC 12320 N.E. 8th Street, Suite 100 Bellevue, WA 98005 November 14, 2005 Our Job No. 11778 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 18215 72NDAVENUESOUTH KENT,WA 98032 (425)251-6222 (425)251-8782FAX BRANCH OFFICES + OLYMPIA, WA + TEMECULA, CA + WALNUT CREEK, CA www.barghausen.com • I I I I I I I I I ' ,,: TASK l TASK2 TASK3 TASK4 TABLE OF CONTENTS STUDY AREA DEFINITION AND MAPS EXHIBIT A Vicinity Map EXHIBIT B Downstream Drainage Map EXHIBIT C Upstream Basin Map RESOURCE REVIEW EXHIBIT D FEMA Map EXHIBIT E Sensitive Areas Folios EXHIBIT F SCS Soils Map EXHIBIT G Assessor's Map EXHIBIT H Wetland Inventory Map EXHIBIT I Basin Reconnaissance Summary Report FIELD INSPECTION EXHIBIT J Off-Site Analysis Drainage System Table 3.1 Conveyance System Nuisance Problems (Type I) 3.2 Severe Erosion Problems (Type 2) 3.3 Severe Flooding Problems (Type 3) DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS EXHIBIT K Drainage Complaints I 1778.003.doc I I I I I ' TASK I STUDY AREA DEFINITION AND MAPS The proposed plat of Cavalla is approximately a 9.4-acre site located within a portion of the Southeast quarter of Section 14, Township 23 North, Range 5 East, Willamette Meridian, King County, Washington. More specifically the site is located on the eastern side of 162nd Avenue S.E. and 200 feet south of S.E. 137th Place and is fairly rectangular in shape. The enclosed Exhibit A -Vicinity Map depicts the approximate location of the proposed site. The existing topography of the site is such that it is undeveloped and consists of forested areas over the entire site. The site tends to slope at an approximate grade of 8 percent in a north-lo-south westerly direction. There is one existing single-family residence located in the northwest corner of the project site. This residence will be demolished with the construction of this plat. The storm drainage facility is proposed to be located in the southwest corner of the project site such that the site will discharge in the same location it does under existing conditions. There are no wetlands located on this project site and road improvements are proposed for half-street widening of 162nd Avenue S.E. The western boundary of the project site is formed by 162nd Avenue S.E. The plat of Liberty Lane forms the project site's northern boundary. Unplatted land, which may be a park area, forms the project's western boundary. There is a proposed development located south of the project site, which will probably be developed concurrently with this project site since it has been previously submitted to King County for plat approval. The proposal for this development is to subdivide the property in 34 separate lots with a separate tract for access to some of the lots and another tract for stormwater quality and flow control facilities. In addition, road improvements will be constructed throughout the project to provide access to the project site's lots. Elevations on the site range from 480 along the northern property line, down to 432 along the southern property line at the southwest corner of the project site. UPSTREAM DRAINAGE ANALYSIS Based on review of the topographic map, the site improvement plans prepared for the Liberty Lane plat located north of the project site, and our site visit it appears there is upstream flow onto and through the site. This upstream flow is all routed to the northwest comer of the property and is conveyed in a ditch along the future right-of-way of 162nd Avenue S.E., where it finally disperses after coursing approximately half way south along the project site's western property line. This upstream basin in approximately 5.4 acres in size, consists of a portion of the developed area known as Liberty Lane plat, and the remainder is undeveloped land. The runoff from the upstream basin will be collected and conveyed separately around the project site by being conveyed in the right-of-way of 162nd Avenue S.E. 11778.003.doc \ \ \ \ \ \~ \ ' .. ' :' / "; \ -DOWNSTREAM DRAINAGE SYSTEM MAP J I I ·~J·-·-· ··~ ' . ~ ~ . .., . . -. --·· ,. ,-..... I I I I I I I I I ![ -: I ~ ' ,<c ., ' ~ .... - j, A .... ---_...:~'" ,,,, IC9U ll11J~1l i '"'"' " 111.n <HJ,., ""'' ,, ... , 145150 CEDAR .;::,., ......... ,, -J :. PARK I~··-------=;:;,~· I r ';' I t----+G4,·'--:!Jt...""( __ ::.---f..·i r """' '"' • ., --, r,. "' , I - - Fl VE ' " ' ,; ,, , ... ,,,,, .. ""' ...... ~. 11~1,,F ACRE TRACTS SITE. ~. "'-JI 'IHOh ... _, - ' :/~ [ I •, .f'. ~ ~m ": = ' ' ' I I l II I • • • • I I • I I • I I I ' ' TASK2 RESOURCE REVIEW • • • • • • • Adopted Basin Plans: The site is part of the Lower Cedar River drainage basin . Finalized Drainalie Studies: This is not applicable . Basin Reconnaissance Summary Report: Once again, the site is located in the Lower Cedar River drainage basin and drains to an area that has no mapped tributary (whicb would have been mentioned in the basin reconnaissance summary report if it had its own drainage basin) . Critical Drainage Area Maps: According to the water quality applications map in the 2005 King County, Washington Surface Water Design Manual (KCSWDM), Basic Water Quality treatment is required. According to the flow control applications map, also in the 2005 KCSWDM, Conservation Flow Control (known as Level 2 Flow Control) is required as a minimum. Floodplain and Floodway FEMA Maps: Please the enclosed Exhibit D -FEMA Map utilized for this analysis. Panel No. 1,001 of 1,725, Map No. 53033Cl001 F, revised May 16, 1995, indicates that the proposed project site does not lie within a floodplain or floodway of a stream. Other Off-Site Analysis Reports: A review of Exhibit I -Basin Reconnaissance Summary Report and the site investigation work conducted in the preparation of this Level 1 Drainage Analysis. The U.S. Department of Agriculture Soils Conservation Service (SCS) soils map is also provided (see Exhibit F -SCS Soils Map). In addition, the off-site analysis prepared for the project site located immediately south of this site was reviewed for conformance with the findings from the off-site analysis performed for this project. Sensitive Areas Folios: Based on a review of the King County sensitive areas map folios, it was found that the subject site does not lie within a sensitive area. However, it does drain to a landslide hazard area further downstream from the project site and, ultimately, into the Cedar River, which is a salmon-bearing river. There are no wetlands or coal mine hazards, etc., associated with this project site or the downstream drainage course . Road Drainage Problems: This is not applicable. United States Depanment of Agriculture King County Soils Survey: Based on our review of the soils map for this area, the entire site lies within Alderwood type soils. Wetland Inventory Map: The wetland inventory map for this area was reviewed and it was determined that there are no wetlands on the site or in the downstream drainage course of the site. Migrating River Studies: This is not applicable . 11778.003.doc RECONNAISSANCE REPORT NO. 13 LOWER CEDAR CREEK BASIN JUNE 1987 Natural Resou,ces and Parks Division and Surface Water Management Division King County, Washington I • I I I I Department of Public Works Don LaBelle, Director King County Executive Tim Hill King County Council Audrey Gruger, District 1 Cynthia Sullivan, District 2 Bill Reams, District 3 Lois North, District 4 Ron Sims, District 5 Bruce Laing, District 6 Paul Barden, District 7 Bob Grieve, District 8 Gary Grant, District 9 Parks, Planning and Resources Joe Nagel, Director Surface Water Management Division Joseph J. Simmleri Division Manager Jim Kramer, Assistant Division Manager Dave Clark, Manager, River & Water Natural Resources and Parks Division Rus.s Cahill, Division Manager Bill Jolly, Acting Division Manager Derek Poon, Chief~ Resources Planning Section Bill Eckel! Manager, Basin Planning Program Resource Section Larrv Gibbons, Manager, Project Management and Design Section Contributing Staff Doug Chin~ Sr. Engineer Randall Parsons, Sr. Engineer Andy Levesque, Sr. Engineer Bruce Barker, Engineer Arny Stankus, Engineer Ray Sleiger, Engineer Pete Ringen, Engineer Consulting Staff Don Spencer, Associate Geologist, Earth Consultants, Inc. John Bethel, Soil Scientist, Earth Consultants, Inc. P:CR Contributing Staff Ray Heller, Project Manager & Team Leader Matthew Clark, Project Manager Robert R. Fuerstenberg, Biologist & Team Leader Matthew J. Bruengo, Geologist Lee Benda, Geologist Derek Booth, Geologist Dyanne Sheldon, Wetlands Biologist Cindy Baker, Earth Scientist Di Johnson, Planning Support Technician Robert Radek, Planning Support Technician Randal Bays, Planning Support Technician Fred Bentler, Planning Support Technician Mark Hudson, Planning Support Technician Sharon Clausen, Planning Support Technician David Truax, Planning Support Technician Brian Vanderburg, Planning Support Technician Carolyn M. Byerly, Technical Writer Susanna Hornig, Technical Writer Virginia Newman, Graphic Artist Marcia McNulty, Typesetter Mildred Miller, Typesetter Jaki Reed, Typesetter Lela Lira, Office Technician Marty Cox, Office Technician I • I I I I TABLE OF CONTENTS 1.· SUMMARY II. INTRODUCTION III. FINDINGS IN LOWER CEDAR RIVER BASIN A. Overview of Basin B. Effecls of Urbanization C. Specific Problems I. Drainage and flooding problems 2. Damage to property 3. Destruclion of habitat IV. RECOMMENDATIONS FOR ACTION V. A. Reduce landslide hazards B_ Reduce erosion and flooding C. Prevenl future erosion and flooding wilh appropriate analysis, planning, and policy development D. Stop present (and prevent future) damage to habitat by addressing specific problems in stream systems MAP APPENDICES: APPENDIX A: APPENDIX B: APPEDDIX C: Estimated Costs Capital Improvement Project Ranking Detailed Findings and Recommendations 1 1 2 2 4 5 5 6 6 7 7 7 8 8 11 A-1 B-1 C-1 • II I. SUMMARY The Lower Cedar River Basin, in southwest King County, is unique in its development pat- terns and the as.sociatcd environmental problems that appear throughout the basin. Except for the city of Renton and areas on the Cedar River Valley floor, most of the development in the basin has occurred on the upland plateaus. Most of this development is recent and primarily residential. In addition, the plateau is the site of numerous sand and gravel mining operations and, in the southern uplands, an abandoned coal mine. Peat is also being mined north of Otter Lake. In some areas livestock are being raised on small farrns; there are no major crop-related agricultural activities in the basin. The effects of development are most apparent where storm drainage is routed over the valley walls. Impervious surfaces on the plateau have increased the rate and volume of storm runoff, resulting in substantial erosion, siltation. and flooding below. In addi- tion, erosion and siltation have damaged or destroyed habitat in many tnbutaries, threatening the suivival of fish. Habitat and water quality throughout the basin are also threatened by the filling of wetlands and the presence of large amounts of domestic trnsh in some streams. The reconnaissance team noted that the Peterson Creek system has so far remained in its natural, nearly pristine condition. Maintaining this quality should be a high priority in future basin planning capital project programs. Recommendations in the Lower Cedar River Basin include 1) designing and constructing appropriately sized RID and other drainage facilities; 2) establishing stricter land use policies regarding floodplains, wetlands, and gravel mining; 3) conducting more detailed and comprehensive hydrau6c/hydrologic analyses of proposed developments; and 4) preventing damage to the natural drainage system. The field team also recommends 5) restoring the habitat of several tributaries ( e.g., cleaning gravels, revegetating stream banks, and diversifying streambeds for spawning and rearing) as well as 6) protecting the nearly pristine quality of Peterson Creek. INTRODUCTION: History and Goals of the Program In 1985 the King County Council approved funding for the Planning Division ( now called the Natural Resources and Parks Division), in coordination with the Surface Water Management Division, to conduct a reconnais.5ance of 29 major drainage basins located in King County. The effon began with an initial investigation of three basins --Evans, Soos, and Hylebos Creeks --in order to determine existing and potential surface water problems and to recommend action to mitigate and prevent these problems. These initial investiga- tions used available data and new field observations to examine geology, hydrology, and habitat conditions in each basin. Findings from these three basins led the King County Council to adopt Resolution 6018 in April 1986, calling for reconnaissance to be completed on the remaining 26 basins. The Basin Reconnaissance Program, which was subsequently established, is now an important ele- ment of surface water management. The goals of the program are to provide useful data v.ith regard to I) critical problems needing immediate solutions, 2) basin characteristics for use in the preparation of detailed basin management plans, and 3) capital costs associated with the early resolution of drainage and problems. The reconnaissance reports are intended to provide an evaluation of present drainage con- ditions in the County in order to transmit inforrnation to policymakers to aid them in developing more detailed regulatory measures and specific capital improvement plans. They are not intended to ascribe in any conclusive manner the causes of drainage or erosion I Lower Cedar River Basin ( continued) problems; instead~ they are to be used as initial surveys from which choices for subsequent detailed engineering and other professional environmental analyses may be made. Due to the limited amount of time available for the field work in each basin, the reports must be viewed as descriptive environmental narratives rnthcr than as final engineering conclusions. Recommendations contained in each report provide a description of potential mitigative measures for each particular basin; these measures might provide maximum environmental protection through capital project construction or development approval conditions. The appropriate extent of such measures will be decided on a case-by-case basis by County offi- cials responsible for reviewing applications for permit approvals and for choosing among competing projects for public conslruction. Nothing in the reports is intended to substitute for a more thorough environmental and engineering analysis possible on a site-specific basis for any proposal. ill. FINDINGS IN LOWER CEDAR RIVER BASIN The field reconnais.'xlnce of Lower Cedar River Basin was conducted in January 1987 by Robert R. Fuerstenberg, biologist: Bruce L Barker~ engineer; and Lee Benda~ geologist. Their findings and recommendarions are presented here. A Overview of Lower Cedar River Basin The lower Cedar River Ilasin is located in southwest King County and is 27 square miles in area. It extends southeast from the mouth of the Cedar River on Lake Washington to approximately river mile 14.0. The boundary to the northeast 1s marked by a ridgctop connecting the city of Renton to Webster and Franklin Lakes; the boundary to the southwest runs along Pelrovit.sky Road to Lake Youngs. Renton is the only incorporated area in the basin. Other popul.:nion centers include Fairwood. Maplewood Heights_ and Maple Valley. Except for the city of Renton, most of the residential concentrations are located on the upland plateaus overlooking the Cedar River Valley. These upland developmenls are recent compared to the smaller established communities on the valley floor. The basin lies "ilhin ponions of three King County planning areas: Newcastle in the nonheast (which includes Renton), Tahoma-Raven Heights in the east, and Soos Creek (the largest of the three) in the wesL Rural areas exist on the valley floor on both sides of !he Lower Cedar River, from approximately river mile 5.50 to 13.00. These -arc limited to pastureland for horse~ COVv--S, and some sheep and several small "u-pick" frnit and vegetable farms. Similar areas are located on the southern uplands above the reach from river mile 5.50 to 7.00 and in the Lake Desire-Otter Lake area. The plateau is also the site of sand and gravel mining operations and, in the soulhern uplands~ of the abandoned Fire King Coal Mine. Peat deposits exist wes1 of Lake Desire and nonh and south of Otter Lake, and peat mining is being carried out north of Otter Like. Present zoning allOVv-s for urban and suburban densities throughout much of the basin~ panicularly on the upland plateaus and in the Cedar River Valley from its mouth to appoximately river mile 6.50. Population projections for the year 2000 in the three plannign areas containing the Lower Cedar Basin are over 311,000, an increase of 47 2 I • • • I I I I I P:LC Lower Cedar River Basin ( continued) percent from the present. Most of this growth will occur in the Soos Creek Planning Area . Dominant geological and geomorphic features. The geology of the Lower Cedar River Basin is diverse. Geological formations exposed along the valley include sedimentary rock~ undifferentiated o1der glacial dri(t, CA1ensive ground moraine deposit.5.i recent alluvium along the Cedar River, and landslide deposits along the river and its tribu- taries. The sedjmentary rocks, composed of moderately dipping sandstones, con- glomerates. mudstones. and shales. are exposed locally along the cliffs of !he Cedar River Valley near the mouth of the Cedar River. In addition, the Renton fom1ation, composed of sandstones. mudstones, and shales with periodic deposits of coal, is also exposed along the lower portion of the Lower Cedar River Valley. Undifferentiated glacial deposits found here are composed of three or more rill sheers, glacio-fluvial sand and gravel, glacio-Jacustrine clay, and sand, and non-glacial sand. clay and thin peat. These lie over the sedimentary rock formations and are best exposed in cross~secrion along the cJiffs of the main valley and major tributaries. The morphology of the Lower Cedar River Basin is dominated by the valley formed by the Cedar River. Vallev walls are steep cliffs formed by landslides in glacial sedi- ments. A once extensive and meandering River, which created a wide valley floor as it cut its way westwardi the Cedar today is diked for most of its length through the lower valley. A narrow but extensive band of landslide deposits exists along the steep cliffs of the main river and its major tribularies. The landslide deposits consist of deformed blocks of glacial sedimenls and colluvium derived from slides or mass flowage, such as landslides and debris flows. Recent alluvial deposits fill the valley and major tribularies. Small, composite, alluvial debris fans exist at the mouths of the largest tributaries. Closed depressions, principally in the uplands, have lacustrine and peat deposits. The Lower Cedar River Valley has a high potential for erosion due to steep slopes and the existence of a clay layer that promotes soil failures. In addition, the confined nature of tributary channels between steep hillslopes promotes bank erosion during high flows. Numerous recent Jandslides are evident along cliffs of many of the steep tributaries and along the main stem of the Cedar River. These have been accelerated by the removal of vegetation and the routing of concenlrated storm flows over steep slopes in areas where development has occurred. Hydrologic aod hydraulic characteristics. The Cedar River Basin is composed of a complex drainage nehvork consisting of the Cedar River and 17 tributaries. The larger tributaries Pegin in lakes or wetlands on the bluffs and flow through relatively flat stable channels to the edge of the Cedar River Valley, then plunge down to the valley floor through steep, erodible ravines. Tributaries of this lype such as Tributary 0304 (wilh headwaters at Wetland 3111) and Tributary 0328 (which begins al Lake Desire), are found on lhe south side of !he Cedar River. Another type of tributary collects surface runoff from urbanized areas. pastureland, and wooded areas. Tributaries 0302, 0307, and 0312 are examples of !his type of tributary. They are interminent (depending on rainfall), shorter in length, flow through shallower channels that arc steeper at the bluffs and transport more material during limes of 3 I • • Lower Cedar River Basin (continued) high flows. Some of the worst problems located during field investigation (see Appendix C for a full listing) occur on this type of tributary. Catchments 5, 6, and 12 have very infiltrative soils. Urban developments hvae utilized RID poinds to effectively infiltrate all urban runoff before it reaches the valley hillslopes. The infiltrated runoff then reappears as springs. Two large lakes (Desire and Otter), together with four smaller ones (Shady, Peterson, Webster, and Francis) lie in the southeast third of the basin. Numerous large wetland areas exist in this section as well. The field team identified 10 potential wetland sites that had not been previously identified in the Sensitive Areas Map Folio (SAMF). The system of lakes and wetlands in this area effectively buffers the high flows draining to these tributaries. Habitat characteristics. With few exceptions, usable fish habitat exists only in peren- nial streams (i.e., Trib. 0302, 0304, 0305, 0328, and possibly 0308). In other streams (e.g, Trib. 0303 and 0310), steep gradients preclude fish use. Steep gradients also reduce fish use in the perennial systems ( except for Trib. 0328). Habitat is in various stages of degradation in these systems; pools are being filled and gravels and debrjs shift regularly. In Tributary 0328 (Peterson Creek), however, habitat diversity is extensive, and the channel is not seriously degraded. At this location the field team observed at least three species of salmonoids. In general, the most diverse and least disturbed habitat in a tributary system occurs in the large wetland areas in the southeast third of the basin. Usable habitat for anadromous fish is found in the Imv-gradient portions of streams where channels cros.s the Cedar River Valley floor. In these reaches, however, only spawning habitat is likely to be available, as the pools and woody debris necessary for successful rearing either do not exist or are quite limited. Excellent spawning and rearing areas exist where pools and riffles are extensive, instream cover and bank vegetation are intact, and diversity of habitat types is abundant. R Effects of Urbanization in the Basin Flooding, erosion, and the degradation of habitat associated with development in the Lower Cedar River Basin are most apparent where development has eliminated vege- tation along the edges of the valley and where stormwater has been routed down channels and swales. The removal of vegetation, such as tre~ above and below the edges of valJey walls, as well as the discharging of stonnwatcr over the valley wall, has resulted in tension crncks and landslides that are endangering some houses. The sedi- ments from these failures are depositing in streams and on valley floors and damaging fish habitat and private property. Discharging stormwater from increased impervious areas into steep tributary channels and sviales is seriously destabilizing channels and valley walls; this in turn results in channel downcutting. bank crosion1 and landslides. The sediments from these problems often degrade fish habitat and settle out on pri- vate property along the valley floor. Two serious instances of development-related erosion occurred during the November 1986 storm: 1) culverts rerouting the stream were plugged1 causing the formation of a new channel that destroyed portions of roads on Tributary 0314; and 2) new, uncom- 4 II Lower Cedar River Basin (continued) pacted fill adjacent to new residences near collection point 5 was washed panly awav during tht: storm, causing landsliding and gullying. Future problems will be similar to these, as commercial and residential developments increase flow rates and volumes by decreasing natural storage and infiltration. This is expected to occur if wetlands on the upper plateau are encroached upon or lost ( e.g., on Trib. 0304 at RM 2.30 and on Trib. 0304A at Rm 1.60). The preservation of wetlands and streambank vegetation and the attenuation of storm flows are essential in this basin. C. Specnic Problems Identified The steep valley sideslopcs through which streams pass and the often dense upland development result in a number of similar problems that repeat themselves throughout the Lower Cedar River Basin. The most significant of these are outlined and discussed below. 1. Drainage and flooding problems are often the result of several conditions: a. Undersized culverts and inadequate entrance stIUctures. The most notable area is on Tributary 0306 at river mile .301 where a culvert here was blocked by debris carried downstream by the stream and caused erosion and flooding of Fairwood Golf Course. The blockage was compounded by Ille fact that the culven was undersized: the problem will wor.sen as flows increase from upstream development. b. Serious instream erosion and subsequent downstream sedimentation. These have been caused by three main factors: I) runoff from residential developments on the bluffs above the valley, 2) compacted pasturcland due to livestock, and 3) runoff from impervious areas originating at gravel pits. These problems will continue and worsen until mitigative measures are taken. (See Appendix C for specific examples.) c. Undersized recbannelized streams. Tributaries on the valley floor are too small to carry the increased flows originating in developed residential an .. -as along the top of the bluffs. For example, Tributary 0302 at river mile .25, the channel along Maplewood Golf Course, ovc:nops and floods during storms. d. Construction in wetland and floodplain areas, Many of the wetlands on the south side of the Cedar River are peat bogs, and roads built through them continue to settle each year, increasing the amount of Oooding on the road. For example, the road crossing with Tributary 0328B nonh of Lake Desire will experience more severe flooding as the road settles. e, Discharging of stormwater at the top of steep ban.ks At river mile 2.20 on the Cedar River, a trailer park ( constructed on the edge of the cliff) discharges its drainage down the valley wall. Increased flows erode the steep valley, depositing sediments on the valley floor, blocking channels and causing flooding. These problems will eventually s1abilize, but only after a large quantity of soil has been eroded. 5 Lov,:er Cedar River Basin ( continued) 2. Damage to property is being caused by lhrce factor.;: a. Landslides and potential landslides. Lmds!ides are accelerated by the· removal of vegetation on steep slopes in preparation for residential construction and/or by the routing of storm flows over hillslopes. For example, a large landslide has already occurred m the front yard of a resi- dence on the Cedar River at river mile 7.80. b. Sedimentalioo (from landslides). Sedimentation and channel and sion are damaging private property along the valley floor (Trib. 0310). hank ero- 0299 and c. Flooding during storms. Flooding has been brought on by the effects of development and associated changes to lhe naturJI drainage systems in the basin. (See "B" above.) 3. Destruction of habit.al is being caused by four conditions: a. Sedimentation of pools and riffles and cementing of gravels. These problems, the result of severe erosion and the transport of bedload material, have been caused by upland developments in the basin and the presence of associated impervious surfaces, which increase the rare and quantity of surface runoff. Sedimentation and cementing of gravels in streambcds destroy natural spawning and rearing habitat. On Tributary 0307 at river mile .40 and Tributary 0305 at river miles . 95. 1.20, and 1. 70, recent high flows have eroded the streambed at least one foot~ contributing to a serious siltation problem downstream. Heavy bedload transport is evi- dent in all systems of the basin except Tributary 0328. In Tributary 0303 at river mile .25, fine sediments are accumulating in gravels that may be used by resident fish. In Tributary 0304 between river miles .95 and J.20, pools are being filled by sands and gravels and rearing habitat is being rapidly lost. b. Cbaruielizatioo of stream beds. Loss of habitat through channelization has occurred in all the major streams of the basin, but most noticeably in those reaches that cross the valley floor. These reaches lack habitat diversitv, reducing fish use for spawning and rearing. Channelization has damaged or destroyed habitat in severed reaches that were once heavily used by fish: these include Tributary 0302 between river mile .30 and ~O, Tritiutary 030-t between river miles .05 and .18, Tributary 0305 between river mile .20 and .75, and Tributary 0328 from river mile l.lO 10 1.40. These systems cannot afford a further reduction of habitat and still remain viable fishery resour- ces. c. The accumulation of trash in stream beds. This problem occur.; in close proximity to residential areas. Trash degrades water qualily and is visually unpleasant. Tires, appliances, furniture, and other trash have been thrown into Tributary 0302 at river miles 1.00 and LIO and in Tributary 0303 at river mile .35. 6 I I I ' li d. Lower Cedar River Basin (continued) Wetland encroachment. Eacroachment destroys habitat and eliminates natural water filtration and storage for surface runoff. Examples of this problem were absented on Tributary 0304 at river mile 2.30, Tributary 0308 at .80, aad Tributary 0304A at river mile 1.80. Many wetlands have already been completely lost through filling, for example on Tributary 0306A at river mile .55. Suspected violations were forwarded to Building and Land Development for eaforcement. RECOMMENDATIONS FOR ACTION The primary recommendations for action in the Lo\\,er Cedar River Basin addresses current severe problems related to erosion, habitat destruction, and flooding. Prevention of these problems will be accomplished by controlling locations and densities of new developn1ent and providing adequate R/0 facilities for stormwater. A Reduce landslide hazards by: 1. Including sensitive areas not previously mapped on the Sensitive An:as Map Folio (SAMF). See Appendix C for a full listing of sensitive areas. 2 Establishing building setbacks along cliffs and native growth protection easements along steep ravines. 3, Discouraging or eliminating the routing of stonnwater over cliffs, unless adequate tightline systems can be constructed to convey flo\\S in a safe. nonerosive manner to the bottom of cliffs. 4. Decreasing peak llows by consrructing larger RID facilities to lessen the landslide and erosion occurrence along tributary slopes. R Reduce erosion and llooding in the basin by improving surface water management: 1. Direct the Facilities Management Section of the Surface Water Management Division to evaluate existing stonn-<leleotioo and conveyance facilities to deter- mine whether they are properly sized to meet current standards. Evaluation should begin with all single-orifice RID facilities. 2 C..onsider an:as other than wetlands as regional Slonn-<letention facilities. Tributary 0300 at river mile .42 is the site for a proposed dam, for example. 3. Utilize existing lower quality wetlands (thore rated other than #1) as regional Slorm-<lctention facilities. Wetlands 3102 and 3142 could provide more live storage, ·ror example. 4. Review channel and culvert capacity for oonveying existing and fulure runoff, and establish floodplain areas in regions of slight gradient for existing and future runoff conditions. 5. Promote the inf"dtration of surface water through the use of retention facilities and open channels instead of pipes where the soil and slope conditions permit. Collection points 5, 6, and 12 on plateaus have such soil conditions. 7 I I I I ' ' '.~c' C. Lower Cedar River Basin (continued) Prevent foture problems of erosion and Hooding with appropriate analysis, planning, and policy development related to surface water management: 1. (',onduct a detailed, comprehensive hydraulic/bydrologic analysis of any proposed developments to determine impacts on the drainage courses downstream. This rs especially critical for areas on the upper bluffs and plateau, which drain over steep, sensitive banks above the Cedar River. 2 Conduct a Sludy of the impact of locating infiltration ponds utilized near the edge of the bluffs to determine their effect on seepage faces on the lower face of the bluffs. This might be accomplished with a computer-based numerical model of the groundwater flw,;. J. Require the tigbtlining of storm drainage down steep or sensitive slopes when they cannot be directed away from the slopes. This is done hy piping the flow down the slope and discharging it at the bottom with adequate energy dis.'iipation. Many or the intermittent tributaries flowing down the banks should be tighrlined as urban development increases flow to them. 4. Construct new R/D ponds with filter berms to improve water quality and reduce fine sediment loads. New RID ponds should have two cells with gravel-berm filters and vegetated SV¥·a1es at the inlet and outlet. Consider Tributaries 0304, 0304A 0302, and 0303 as sites for this type of facility in order enhance water quality. 5. Maintain natural vegetation on streambanks and Hoodplains. This is especially important for relatively flat channels flowing on the plateau before they reach the steep bluffs because these channels and their floodplains will attenuate flows during times of heavy runoff. 6. Maintain buffer areas around wetlands. Many of the tributaries on the south side of the Cedar River headwater at wetlands. These wetlands act as natural storage areas during storms. 7. Reevaluate King County policy regarding permitting for gravel mining on steep, sensitive slopes. 8. [nclude the city of Rention in future interlocal agreements for planning and capi- tal improvement projects where city and county interests overlap. D. Eliminate present damage lo habitat and prevent future damage by addressing specifk problems in the stream systems. The foIJowing activities should he coordinated among King County, the Muckleshoot Indian Tribe, and State Departments of Fisheries and Game: 1. Reduce damaging storm Oows with greater detention volume and lov.rer release rates at upstream developments. 2 Implement restoration projects on Tributaries 0304 (river mile .00-.20), Trihutary 0305 (river mile .20-.80), Tributary 0303 (river mile .25-.35), and Tributary 0328 (river mile 1.10 -1.40): 8 -a • • I I I I i 3. 'Jo'. :~f( Lower Cedar River Basin (continued) a. On Tnl>utary 0304: Qean streambed gravels, add habitat and bed-control weirs, and plant bank vegetation for shade. b. On Tnbutary 0305: Construct a new channel and move stream from road- side channel to its new location on adjacent lands. Implement a full restoration project to provide channel meanders, habitat structures, pool/riffle enhancement, streambed gravel replacement, and revegetation. c. On Tnbutary 0303: Move stream from present channel to a location further north, away from the roadside. If relocation is not possible, these minimum steps should be taken: Add habitat structure to existing channel with root masses, deOectors, boulder clusters, and other features; revegetate channel banks with shrubs and small trees; enhance stream crossings with bonomless pipe arches. d. On Tnbutary 0328 (Peterson Creek): Add habitat structure by replacing the straight, shortened channel with a more natural, meandering one; place habitat structures (such as root masses. deOectors, cover logs, and boulder clusters) throughout the channel; and revegetate banks ,,.;th shrubs common to adjacent riparian zones (salmonberry, ninebark, or dogwood, for example). Protect the Peterson Creek system (Tnl>. 0328) in its present, near-pristine state. This will include not only the restoration outlined in section A above, but also the adoption of land use management regulations to prevent future habitat destruction: a. Protect aU existing wetlands within the subcatchments of Peterson Creek. Employ wetland buffers at least 100 feet wide 'without exception. b. Restrict development in the critical headwater area ( drainage, habitat, water quality) bounded by Lake Desire, Otter Lake, and Peterson Lake to rural densities. c. Designate and protect streamside management zones of at least 100 feet from the ordinary high-water mark (OHWM) along the main stem of the creek. Use 25 feet from the OHWM on tributaries. d. P,csen,e floodplains and their forests for dynamic retention of sediments and water. e. Restrict vegetation removal in streamside/wetlaod management woes. f. Sae R/D facilities to store the 100-year storm at a two-to-five-year release rate. Use the two-cell type of pond with a forebay, a gravel filter, and a vegetated swale outnow where feasible. g. Regulate more closely aU septic tank and drain..f"icld iostaUations, as well as maintenance schedules, particularly in the Lake Desire, Oner Lake, and Peterson Lake drainage areas. 9 Lov ... cr Cedar River Basin (continued) h. Work with the State Department of Ecology to establish minimum stream- lJow requirements for Peterron Creek and Lake Desire tributary. 4. Develop and promote public education and involvement programs for basin awareness. Work with school5:, environmental groups, and the civic and business communities to conduct educational and restoration programs. 10 ' I ·'0:-, '<~, "•» •:- '\ _, . ..-" \ '"t··t.c'ccc,,, •. -. . . •. '<·,,\ \ h. 1 ~ .. • J} . \. ;~ ~-... I :'t :...i : ~ --\ ~\ ;:' . \ . +· \' \ ·-, '-\ ~····.·J\'.J;;~ .. : ''lfl~,o "·· . -~,,-'.< /0'1!'0; ·, ,. \ \ \ 11\\ : -.. -... .:.. --.. · -1 .. -... (;.~~\\.\ \ ,;~+:. " r · !ii 1 . .< .. , • · 1 ·· • -:----1,;.· ~-7;.·;:, ... · ... .•.. . ( I~ ~'1 .. ,:.· . L "'r--~· '<;. .,-~--r· .. \~·/.~:~>~\--~;:: ··:.: . . ... :~· --~~---+---.._.I .. , "1.c.,,,l;,11; 1/i', ·... 0 'Ye. ~ •, f.;. , I'. . ";-~ ... --.':. t'. 1, '- Basin Boundary ® Subcatchment Boundary ~l \ ', :W !..i Collection Point i"J ___,,.. Stream 0299 Tributary Number ~ ea115 Proposed Project 0 July, 1987 I\ ;: .cJ·1r·i~ ., ', c,::~it,~:ti. ' -· w ,. --. ~--\\--:~):~ '·· ~i ' f 2 Miles (\ < -..... i,P ·: \ ·~ --'---~ N + n " " ( -> l~--..__._ '• ~-\ 1-;, • Ill\ .~--~ - ® i / S' ·. \. lt._ -rr---~ / ;:( .1zt.~-·'"g,'?' .. 0.//iJ>;, •• \ (;/' ! ·- ·~ )-~j, \ ~!.,~'(,;~;· 311}• • . .C;r1; ' ' ~+ APPENDIX A ESTrMATED COSTS: PROPOSED CAPITAL IMPROVEMENT PROJECTS LOWER CEDAR CREEK BASIN Indicates project was identified by Surface Water Management office prior lo reconnaissance. NOTE: Arr projects are located on map included in this re_eort. Project Numhcr JJ05' 3109' !':LC.APA Collect. Point JO IO Proicct Description Enhance 2200' of Trih. 0305 from Cedar River to Elliot Bridge. Secure easements to wetland located in Cascade Park and construct a berm at the outlet. Replace existing catch hm;ins with control stn1cturcs. Project should he justified hy a basin study. Welland rated #2. (This wetland will require further biological evaluation before R/D design and construction.) Problem Addressed Mitigates flooding of King County park land. Better utilizes wetland's storage capacity to address peak flows from surrounding urban area. A-1 Estimated Costs and Comments $115,000 (NOTE: This project was proposed hy Surf.ace \Vnter Management, is in the design phase, and will be constructed by 1989.) $186,000 3111 (Wetland 3136) 3112 (Wetland 3142) 3114" (Wetland 3150) 3115 P:LC.Al'A 19 18 Descrigtion Secure easements to out'let to Francis Lake and 1100' of channel from lake to SE 184th St. Construct a weir to rnisc lake level 1', and enhance 1100' of Trib. 0317. Should be justified by a basin plan. Wetland rated # J. (This wetland will require further biological evaluation before R/D design anti construction.) Secure easement for outlet to wetland and replace existing weir with a concrete.slotted weir. Should be ju~tified by a brtsin plan. Wetland rated #2. (This wetland will require further biological evaluation before R/D design and construction. Secure casement to Wetland 3150 and construct a containment berm and control structure at the outlet. Project should be justified by a basin plan. Wetland rated #2. (This wetland will require further biological cvuluation before R/D design and constrnciton.) [nstall detention pond and 1,000' of tightlinc. Project is indepen- dently justifiable. Problem Addressed Will provide additional storage to mitigate anticipated future increased flows. Will provide additional storage for anticipated future peak flows. Addresses anticipated increases in flow caused by development. Mitigates severe erosion and flooding during times of high flows. A-2 Estimated Costs and Comments $175,000 $117,000 $134,000 $361,000 Yll6 3117 3] 18 3119 3120 P:LC.APA Collect. Point 21 16 JO 4 15 Proicct Description Rnise existing road embankment 2-4'. Project should be indepen- dently justifiable. (Refer to Roads Division.) Install 1,400' of tightline, a sediment trap, and 700' of channel from Jones Rd. to Cedar River. Project is independently justi- fiable. Install 300' of 36" culvert, a new inlet structure, manhole, and catch basin. Project is independently justifiable. Construct a detention dam and control structure in a deep channelized section of Trib. 0300. Project is independently justifiable, Conslrt1ct a sedimentation pond and 1,000' of clianncl from Jones Rd. to Cedar River. Project is indcpen~ dcntly justifiable. Problem Addressed Mitigates seasonal flooding of I~1ke Desire Dr. SE caused by road bed settling in the peat bog. Mitigates severe erosion, sediments deposited on County roads, and flooding during times of high flows. Will prevent blockage of culvert and the accornpanying flooding: and erosion of Fairwood Golf Course and mobile home park below. Project location is ideal because it addresses flows from a large residential area before they reach the steep, sensitive area next to the Cedar River. Mitigates flooding of residence and sediment deposition on Jones Rd. A-3 Estimated Costs and Comments $73,000 $501,000 $87,000 $159,000 $163,000 :1122 11 P:LC.APA Scci1re casement 10 wetland and cona struct n containment berm and concrete weir at outlet. Project should he justified by a basin plan. Wctlancl rated #2. Uiolog:ical assessment is needed to assure that this project does not decrease habitat values. Purchase existing ponds on Fai:r,,vood Golf Course and expand to provide grc,uer flow detention. Project is independently justifiable. Problem Addressed Addresses increased flows in Trib. 0304 anJ OJO..JA from residential developments. Mitigates flooding and erosion downstream. A-4 Estirnated Costs and Crnnmt:nts $:171,000 $342,000 APPENDIX B CAP!T AL IMPROVEMENT PROJECT RANKING LOWER CEDAR RIVER BASlN P1ior to the Lower Cedar River Basin field reconnaissance, 12 projects had heen identified and · rated using the CIP selection criteria developed by the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Following the reconnais.,;ance, 13 projects remain proposed for this area. They include eight new, previously unidentified and unrated projects. These displace seven previously selected projects, which were eliminated based on the consensus of the recon- naissance team. Projects were eliminated for several reasons: ffi'O sites were annexed by the city of Renton, two projects were found lo be unneces.sary, two sites were categorized as #1 wetlands (and are· ineligible), and one project was determined to be infeasible. The previous SWM capital improvement project list for the Lower Cedar River Basin had an esti- mated cost of $1,710,000, while the revised list increases to an estimated cost of S2, 784,000. This 3 percent increase in estimated capital costs is due to the addition of projects after the reconnaissance. The following table summarizes the scores and costs for the CIPs proposed for the Lower Cedar River Basin. These projects were rated according to previously established SWM Program Citizen Advisorv Committee criteria. The projects ranked below are those for which the first rating question, ELEMENT 1: "GO/NO GO," could be answered affirmatively. Projects with scores of 100 ./ or higher can be considered now for merging into the "live" CIP list. RANK PROJECT NO. SCORE COST 1 3122 103 $342,000 2 3118 90 87,000 3 3120 75 163,000 4 3109' 67 186,000 5 3121 65 371,000 6 3117 60 501,000 7 3115 60 361,000 8 3116 55 73,000 9 3114' 28 134,000 10 3111' 25 175,000 11 3112' 17 117,000 12 3119' 15 159,000 13 3105 12 115,000 TOTAL $2,784,000 • Projects proposed prior to the Reconnaissance Program B-1 Aii"iiems listed here are located on final a1sp1ay maps in the offices of Surface Water Management, Building and t..and .Q1!itvelopmen1 1 and Basin Planning. Trib. & Collect. Item• River Mile Point Category Prop. Proj. 1 .. 5 Geology 2 18 Geology . 3 fg22 4 Geology RM 2.6 4 0299 16 Geology RM 9.65 P: LC.APC Existing Anticipated Conditions and Problems Conditions and Problems Recommendations Gullying and landslides in Continued erosion . Recompact fill, revegetate, uncompacted fill in new and drain adequately. development near edge of steep hillslope. Small landslide has formed None (natural failure). None. debris flow (11/86). Sedimentation in yard of residence . Landslides in sedimentary Natural failure. None. rock in cutbanks adjacent to railroad. Drainage from residential Increasing erosion. Provide adequate R/0 to area is resulting in attenuate flows. gullying in swale. C-1 6 13 Geology 7 7 Geology 8 2 Geology 9 14 Geology P: LC.AFC ~",'5•>0-':·· uplands has extensive imper- vious surfaces, resulting in channel scour, bank erosion, landslides, and sedimentation at mouth of basin. Residence overcome with sediment. Landslide terrain for sale by realtors. High risk for landslides, flooding (from springs). Large-scale landsides adjacent to Cedar River due to springs and cutting of toeslopes by streams. Appears to be natural. Gullying in valley wall, possibly from natural springs. Landslide debris flow from residence on SE 147th Pl., Renton. C-2 Continued high erosion and sedimentation. Site of future mass erosion. Natural process. Unknown. Existing tension cracks indicate future instability. Recommendations Develop R/D at horse farm to attenuate peak flows. See Project 3115. Prohibit development here. Notify Building and Land Development. Add area to SAMF. None. None. Revegetate hillslope with trees and shrubs. Trib. & Collect. lli.!!, River Mile Point 10 11 12 13 14 15 0299.lA RM .08 0300 RM .00-.40 0300 QW RM 1.40 0302 RM .50 0302 RM .80-1.00 P: LC.APC 21 4 4 4 6 6 Existing Category Prop. Proj. Conditions and Problems Hydrology 3116 Geology Hydrology 3119 Hydrology 3109 Geology Geology Frequent flooding of county road caused by low road embankment. Extensive channel and bank erosion ·and numerous landslides due to development-related stormwater. Development-related peak flows have caused sig- nificant bank erosion. Collection point 4 has been nearly completely urbanized. Channel downcutting and bank erosion. Bank erosion (medium den- sity) at meanders and obstructions. C-3 Anticipated Conditions and Problems Road located on top of peat bog and will continue to settle, aggravating flooding problem. Problems will continue. Increased erosion on hillslopes below. Degradation of Trib. 0300 from RM .42 downstream. This section is very 'steep and susceptible to erosion. Will continue at same level or increase. Increasing erosion with increasing flow from devel· opments. Recommendations Elevate the road 3-4' by filling on top of the present road embankment. Also stabilize embankment. Provide adequate R/D in uplands. (See Project 3119.) Construct detention dam in deep, channelized reach of Trib. 0300. Construct berm and standard control structure at outlet to Wetland 3120 in Cascade Park. Control storm flows from uplands. Provide adequate R/D in uplands as area develops. 16 17 18 19 20 21 0.102 0302 RM .60-.80 0302 RM.35 0302 RM .45 0302 RM .50 0302 RM .90 P: LC.APC Prop. Proj. 6 Geology 6 Geology 6 Habitat 6 Hydrology 6 Habitat 6 Habitat Problems Gully erosion from broken culverts. Severe gully erosion creating small valleys from daylight culverts. Stream channeled along golf course road. No overhead cover. No habi- tat diversity. Tributary drains down steep bluffs on north side of Cedar River, carrying debris and flooding Maplewood Golf Course. Water supply darn. Full barier to upstream migration. Impoundment is filling with sediment. Severe gullying from right bank corregated metal pipe. Heavy sediment delivery to stream. C-4 Anticipated Conditions and Problems None. Culvert has been repaired. Continued erosion. While fish now use this reach, lack of habitat will eventually reduce popula- tions. Problem will worsen as development upstream continues. As impoundment fills, storm- water will flood over bank. Strncture may fail. Will continue to erode until reaches till layer. Recommendations None. Tightline flows to moin stem. Add habitat diversity ( e.g., structures, overhead vegetation). Gain easement to restore mean- ders, if possible. Constrnct detention dam upstream of golf course. Dredge pond and maintain it as sediment catch. Tightline downslope. Add velocity attenuator at stream. 22 23 24 25 26 ~ RM 1.00 0302 RM 1.10 0303 0303 RM .25 ~ RM .35 P: LC.APC 6 6 6 6 6 Existing Category Prop. Proi. Conditions and Problems Habitat Habitat Geology Habitat Habitat Trash in stream (auto, tires, appliances). Trash in stream. Water quality problem, unsightly. Extensive bank erosion in upper portions of tribu- tary. Habitat suitable for resi- dent fish. Sediment accu .. mulating. Trash and litter in channel affecting water quality, causing erosion. C-5 Anticipated Conditions and Problems Area adjacent to corridor, will continue lo collect trash and debris. Further worsening of water quality, sedimentation, erosion. Area adjacent to corridor, will continue to collect trash and debris. Further worsening of water quality. None. Sediments will eventually cover gravels. Habitat will become unsuitable for fish use. Further decreases in water quality. Recommendations Remove trash. Distribute educational materials to streamside residents. Cite violators, if problem persists. Remove trash. Distribute educational materials to streamside residents. Cite violators, if problem persists. Increase RID volumes, slow release rate to nonerosive levels. Control stormwater volumes and discharge rates from developments. Manually clean gravels when necessary. Remove trash and litter. Distribute educational materials to streamside residents. Cite violators, if problem persists. 28 29 30 31 0304 RM 2.10 0304 RM 2.30 0304 RM 2.40 0304 RM .80 P: LC.APC 7 Habitat 8 Habitat 8 Hydrology 8 Habitat 7 Geology Problem}; L1ndslides contributing sediment to clrnnnel. Heavy deposition in pools, at obstructions, even in riffles. Horses have access to stream, causing some bank deterioration and possibly affecting water quality. Flooding caused by failing RID at 176th St. & 146th Ave SE. Encroachment occurring along all boundaries of this headwater wetland. Several gullies due to daylight culverts; a few have recent landslides. C-6 Anticipated Conditions and Problems_ Sediment will continue to enter system until landslide stabilizes. Further decreases in water quality, bank erosion likely. Problem will continue until outlet structure is modified. Wetland likely to be reduced slowly until it is completely destroyed. Loss of storage, filtration, organic production, and wildlife habitat. Problem will continue. Recommendations Maintain riparian corridor with setbacks at least 50' from tops of banks. Encourage residents to fence channel back 15' from ordinary high-water mark. Limit .access to livestock to one or two points .ilong stream. Problem referred to Main- tenance section of Surface Water Management Division. Require encroaching fills to be removed. Establish specific buffer around this wetland. Enforce sensitive areas ordinances and regula- tions. Tightline drainage. 32 33 34 36 37 0304 RM .00 0304 RM .20 0304 RM .62 0304 RM .80 0304A RM 1.30 P: LC.APC 7 7 7 7 7 Existing Prop. Proj. Conditions and Problems Habitat Habitat Habitat Habitat Hydrology 3102 Extensive riffle (to RM .15. Creek channeled. No woody debris, little bank vegetation. Steelhead, coho spawners here. Debris jam may be a partial migration barrier. Debris jam. Bed drops 3' over jam and sediment, forming anadromous barrier. Water turbid; oily sheen and odor present. Storm drains empty directly into stream. Existing forested wetland provides detention for Trib. 0304A and 0304 in heavily developed area. C-7 Anticipated Conditions and Problems Gravels risk becoming cemented. Few resting areas for upstream migrating fish. Debris will continue to accumulate. Channel will likely divert or jam will fail, releasing accumulated sediment. Debris will continue to accumulate, Channel will likely divert or jam will fail, releasing accumulated sediment. Water quality will continue to decline as runoff and waste enter stream. Additional storage could be utilized by constructing berm and weir at outlet. This could be done to atten- uate increased peak flows as upstream area develops. Recommendations Enhance habitat by addi- tion of woody debris in stream. Revegetate bank. Enhance pool/riffle ratio. Selectively remove debris to allow fish passage. Stabilize large woody debris. Selectively remove debris to allow fish passage. Stabilize large woody debris. Educate residents about how to maintain water quality. Mark storm drains with "Dump no oil" signs. Emphasize recycling of oil. Construct a proportional weir and berm at wetland outlet. Project could be used instead of Project 3107 to rpeserve the #1 rated wetland (where prnject would be built). Anticipated Category Prop. Proi, Conditions and Problems Conditions and Problems Recommendations 38 0304A 18 Hydrology 3115 Runoff generated on top of Flooding will continue as -Construct detention pond RM .40 bluffs on southwest side long as land use remains the at top of bluffs. of Cedar River is causing same on top of bluffs or Tightline drainage down severe bank erosion, until mitigating measures bluffs, then channelize it flooding and debris flows are taken. Runoff origin-to an existing ditch onto several residences ates from highly compacted alongside SR 169. of valley floor. pastureland on uplands. • Prevent similar problems elsewhere with land use regulations, including provisions for preservation of vegetation buffers near tops of cliffs. 39 0305 10 Geology Extensive bank erosion, Susceptible to increases Attenuate high flows. partly due to subsurface with increasing storm flow. clay layer and landslide topography. 40 0305 10 Geology Local severe bank Problem will continue. Existing rock-filled RM 1.10 erosion. gabions are deflecting flow. 41 0305 10 Geology Extensive channel down-Continued erosion. Attenuate high flows with RM 2.10-cutting and bank erosion. adequate R/0. (RID 1.75 currently exists,) 42 0305 10 Geology Several gullies and asso-Erosion will continue. Tightline culverts. RM 2.15-ciated landslides due to l.1S daylight culverts on steep slopes adjacent to chan- nets. P: LC.APC C-8 -- Existing Anticipated Item River Mile Point Cntegorv Prop. Proj. Conditions and Problems Conditions and Problems Recommendations 43 0305 JO Habitat Madsen Creek in ditch along Potential for fuel entry in-Acquire 30' easement away RM .20 SE Jones Rd. Heavy silt; to creek. Further decreases from roadside. Construct road runoff; water quality in water quality can be ex-new stream channel. adversely affected. pected. 44 0305 10 Habitat Creek in ditch along south Further decreases in water Acquire 30' easement away RM .35 side of SR 169. Heavy quality can be expected. from roadside. Construct inputs of oils, anti-Potential for autos to enter new stream channel. freezes, heavy metals, channel. L1ck of habitat. organic pollutants likely. Sand, silt from roadside (of SR 169) enters also. 45 0305 RM .00-10 Hydrology 3105 Section of Trib. 0305, Flooding will continue. Construct and enhance 2200' of .40 RM .00-.40 is experiencing (See Appendix A, Project channel through undeveloped extensive flooding. 3105,) King County Park Land. 46 0305 10 Habitat Channelized along dri-Further siltation, water Acquire easement; move RM .50 veway; lacks habitat quality degradation can be creek from driveway diversity. Driveway scdi-anticipated. Lack of habitat 10-15'. Add meanders and ments enter channel, and precludes optimum salmonid habitat structures to oil. placed on driveway use. increase diversity. enters stream. 47 0305 10 Habitat Channelized tributary Little salmonid use Add structures to increase RM .65 lacks habitat di':'crsity1 anticipated. Spawning and diversity in stream. cover for salmonids. rearing success limited Manually clean gravels by Gravels compacted. (unless reach is restored). churning them. P: LC.APC C-9 48 49 50 51 52 0305 RM .90 ~ RM .95 0305 RM 1.20 0305 RM 1.70 mo6 RM .40 P: LC.APC Categorv JO Habitat JO Habitat JO Habitat 10 Hahitat JO Geology Existing Prop. Proj. Conditions and Problems Good spawning riffles occur here. Vi .. J" gravels, few fines, not compact. High flows are moving material, however. Severe bank cutting and erosion occurs here. Ded SC<Juring evident. Reach subject to high, rapid flows. Much woody debris movement and numerous debris jams. Reach is subject to high, rapid flows. Channel erosion, bank failures, downcutting oc- curring. Reach subject to high, rapid flows. Failure of manhole during 11/86 storm has resulted in gully erosion. C-10 Anticipated Conditions and Prohlems Increased flows may cause gravel har movement. Suitable gravels may be transported downstream to tinusable areas for spawning salmon ids. Further erosion/scouring can be expected. Channel deterioration will continue. Flows appear to be generated at developments. Debris jams will occur with greater frequency as flows increase. Sediments will build up and channel will divert. Further channel deteriora- tion may be expected. Silt, sand transport to mainstem will increase. Not applicable. Recommendations Control flows into system from developed areas upstream. If necessary, add bed controls to hold gravels or "vee" struc- tures to recruit them. Control high flows by increasing upper basin RID facilities, lowering discharge rates to stream. Control upstream flows with greater RID volume, lower discharge rates. Selectively remove debris, Increase RID capacity. Decrease discharge rates. Repair manhole. [tern R;ver Mile Po;nt 53 54 55 56 57 58 0306 RM .20 0306 RM .30 QJQ§ RM .25 QJQ§ RM .30-.45 0306 RM .30 0306A RM 1.30 P: LC.APC 10 10 11 JO 11 Existing Category Prop. Proj. Conditions and Problems Geology Geology Habitat Geology Hydrology 3118 Hydrology 3122 Channel downcutting, bank erosion and several landslides, due both from increased storm flows and development along edge. Undersized culvert in arti- ficial fill in golf course threatens to build lake and possibly overtop bank. Breach flood possible. Ciiannel subject to high1 damaging flows. Erosion evident. Downcutting, bank erosion and landslides. Trib. 0306 connects with large tributary at manhole here. Debris from 0306 clogs this manhole, causing severe erosion of Fairwood Golf Course. Existing small ponds on 0306A are overtopped and receive considerable silt during high flows. The ponds are located on Fairwood Golf Course. C-1 l Anticipated Conditions and Problems Erosion will increase. Clay layer in valley makes area sensitive to landslides. Possible fill failure: Lake ponded behind culvert in in 1981 and threatened the fill. Furtlier channel damage can be expected. Sediment transport downstream will continue, Will continue or increase in future. Problem will worsen as development upstream continues. Area upstream is developing quickly, thus worsening the problem. Recommendations Further increase in runoff should be attenuated; this is a sensitive channel. Enlarge the corregated metal pipe and/or construct adequate trash rack. Increase RID capacity, decrease discharge rate. Attenuate storm flows. Replace existing pipes with larger diameter pipes (if downstream analysis allows for increased flows). Install new inlet struc- tures with trash racks. Acquire easements for ponds and additional area around ponds and construct detention pond. Location is ideal for addressomg peak flows before they reach the sensitive Cedar Reivcr bluffs. 59 60 61 62 63 0306A RM .25 0307 RM .10-.40 0307 RM .10-.60 0307 RM .30 0307 RM .60 P: LC.APC Prop. Proj. 11 Habitat 12 Geology 12 Geology 12 Habitat 13 Hydrology and Problems Some usable habitat exists for resident salmonids. Water quality is poor. Channel subject to high flows. Extensive bank erosion at all meanders and obstruc- tions (trees, cars) due to increased flows from development. Stream eroding toes of slopes resulting in landslide failures. Stream channel pushed to one side of ravine for roadway, High energy system. Much bank cutting 1 sediment transport, debris movement. Area on top of hluffs near Trib. 0307 has excellent infiltrative capacity. C-12 Anticipated Conditions and Problems Further habitat deterioration likely. Channel erosion will increase. lncreascd erosion will result with increased flows. Increasing erosion with increasing flows. Erosion will worsen as stream flows increase. May threaten road bank at toe of slope. Infiltration sites should be used whenever possible. These would provide ground- water recharge. Recommendations Increase RID capacities. Decrease discharge rates. Encourage use of 2-cell detention ponds, swales. Prohibit filling of existing wetlands, ponds in upper basin. Mitigate development- related high flows. Provide adequate RID. Mitigate development related high flows. Provide adequate RID. Increase RID capacity at all delivery points. Reduce release rate below channel scour level. Construct retention faci- lities for new develop- ments in area at these sites. ltcm 64 65 66 67 68 Trib. & Collect. River Mile Point QJQ2 RM.10 0310 RM .60 0310 RM .05 0310 RM 1.50 mto RM .25 15 15 15 15 15 P: LC.APC Categorv Habitat Geology Geology Geology Habitat Prop. Proj. 3120 Existing Conditions and Problems Subject to heavy, rapid flows. Channel erosion, deposition bars migration. Sedimentation upstream from culvert due to debris and undersized culvert. New corregated metal pipe con- tinues to pass water through. Severe erosion below culvert, severe sedirncn ... ration in residence yard. Road drainage forming gully adjacent to road; road bed in danger. Corregated metal pipe is anadromous barrier. C-13 Anticipated Conditions and Problems Erosion, deposition will increase. Sediments will migrate downstream, creating a water quality problem. Continued sedimentation. Continued erosion and sedimentation. Continued erosion. Problem will continue. Recommendations Control storm flows upstream. Control volume and discharge rates. See "Hydrologic and hydraulic characteristics" section in this report. Install energy dissipater below corregated metal pipe. Excavate channel through yard where original channel was located. Reroute drainage. Refer problem to Roads Maintenance. Reinstall corregated metal pipe at or below bed level. 69 70 71 72 73 0310 RM .40 0310 RM .60 0311 RM 1.70 0314A RM .20 0314A/ 03!4D RM .10-.40 P: LC.APC 15 15 13 16 16 Existing Categorv Prop. Proj. Conditions and Problems Hydrology 3120 Habitat Geology Hydrology 3117 Geology Existing channel draining off bluffs on north side of Cedar River, causing flooding of residences and debris flows onto Jones Rd. during peak flows. Corregated metal pipe outlet approximately 9' above bed level. Complete barrier to fish. Old culverts at bed level are plugged. Gully erosion in drainage swale due to outflow of wetland that partly seems to act as an R/D facility. Severe erosiont flooding, damage to County and private roads from increased runoff from gravel pit operations on hillside. Inadequate R/D, plugged culvert caused by exten- sive channel and bank erosion and landslides. Water has cut a new channel. C-14 Anticipated Conditions and Problems Frequency and severity of problem will worsen as development on bluffs increases. Problems will continue and worsen as outfall velocities will scour bed and banks. Upstream has recent (11/86) deposition up to 4 1 deep. Continued accelerated ero- sion. Problem will be aggravated as area above develops. Not applicable. Recommendations Construct detention pond on upstream side of Jones Rd. to trap sediments, and enhance 1,000' of creek from Jones Rd. to Cedar River. Remove new and old pipes; replace at lower level with oversized pipe with trash rack. If possible, enlarge R/D prior to its outlet in the wetland. Tightline drainage between detention ponds in gravel pit. Construct detention pond next to Jones Rd. to trap sediments. Constrnct channel from Jones Rd. to Cedar River. See hydrology comment above. Existing Anticipated l"tem River Mile Point Category ProQ. Proi. Conditions and Problems Conditions and Problems Recommendations 74 Qill Hydrology 3111 Francis Lake is only Trib. 0317 flows through Constn1ct proportional RM 1.60 hydraulic control for steep area downstream of weir at outlet. Trib. 0317. lake. If area around Francis Enhance 1,100' from L1ke develops, increased Francis Lake to SE 184th St. peak flows could cause severe damage to Trib. 03 I 7 in the steep region. 75 0320 Hydrology 3114 Existing forested wetland If surrounding area urbana Constrnct containment berm RM 2.40 with large amount of una izes, this would be a good and control strncture at utilized storage. Wetland site to attenuate peak outlet of wetland (if bio-currently detains flows on flows. logical analysis permits). Trib. 0320. 76 0318 19 Habitat Salmonid parr in many Decrease in water quality Establish and maintain RM.JO pools. Large pools up to with increasing develop-adequate buffers, 100' 1.75' deep. Some deposi-ment. Loss of habitat. from ordinary high-water tion in pools, behind Decrease in fish use. mark or 25' from top fo obstrnctions. slope break, whichever is greater. 77 0382 19 Habitat Salmonid use apparent from System is mostly in natural Maintain adequate stream RM .35 carcasses. Sockeyc, condition. As development corridor buffers. Chinook spawners. Some increases, higher flows and Reduce discharge rates to sedimentation occurring. worse water quality can be pre-development levels. expected. Prevent clearing, grading within buffers. P: LC.APC C-15 78 79 80 81 Jill§ RM .50 0328 RM .70 Jill§ RM 1.10 1.40 0328 RM 1.40 P: LC.APC 19 Geology 19 Habitat 19 Habitat 19 Hydrology 3112 Problems Medium-density landslides and high-density bank erosion occurring due to natural causes. This indi- cates channel and valley sensitive to effects of development. (Sensitivity due to clay layer. Basin hosts some of best fish habitat in upper reaches.) Significant salmonid use throughout. Sockeye spawnersj carcas.c;es present. Coho, steelhead parr in pools. Excellent habitat for spawning and rearing (a redd site). Much diversity ·• most exemplary in basin. Channelized reach. Uniform channel, no habitat diver- sity. Heavy sand deposition. Little overhead canopy or bank vegetation. Lake Peterson is small, open-water wetlam.l with a weir at outlet. C-16 Anticipated Conditions and Problems None. Sedimentation from upstream reach possible. Adjacent development will likely reduce diversity and quality of habitat. May cause thermal problems as water temperatures rise. No useful habitat. Lake provides good peak flow attenuation and will become more important as upstream tril1utary area develops. Recommendations Limit development in the basin. Maintain leave strips adjacent to stream at least 100' from ordinary high-water mark. Restrict use/development within this streamside management zon-e. Restore stream habitat throughout: add structure, diversity, bank vegetation, and canopy. Cost should be borne by party(ies) who channelized this reach. Replace weir at outlet with a higher weir in order to gain additional storage. Surface Water Design Manual, Core Requirement #2 Basin: Cedar River Subbasin Name: Subbasin Number: --------------- Distance Observations of Field Inspector, Drainage Component Drainage Component from Site Existing Potential Resource Reviewer, or Symbol Type, Name, and Size Description Slope Discharge Problems Problems Resident Constrictions, under capacity, ponding, Type: sheet flow. swale, stream, overtopping, flooding, habitat or organism channel, pipe. pond; size, Drainage basin, vegetation, cover, destruction, scouring, bank sloughing, Tributary area, likelihood of problem, See Map diameter, surface area depth, type of sensitive area, volume % Ft. sedimentation, incision, other erosion overflow pathways, potential impacts l. Sheetflow off south Discharges to seasonal stream 5.15 0 -660 None Noted None Noted property line through forested area 2. Seasonal stream 2-foot bottom, 2 feet deep, 1: 1 1-2 660 -1,060 None Noted None Noted side slopes 3. Dispersed flow through Courses south 2 1,060 -1,260 None Noted None Noted thick brush and blackberries 4. Rockery wall Covered by blackberries -1,260 -1,265 None Noted None Noted 5. Broad channel may be Grass lined, 40-by 170-feet I 1,265 -1,435 None Noted None Noted detention pond 6. 18-inch CMP Flows south from channel to 1 1,435 -1,450 None Noted None Noted catch basin 7. 18-inch CMP Flows south from catch basin 1 1,450 -1,490 None Noted None Noted to catch basin on south side of S.E. 144th Street 8. 18-inch CMP Flows west from catch basin to 1 1,490 -1,612 None Noted None Noted catch basin 9. 18-inch CMP Flows west from catch basin to I 1,612 -1,928 None Noted None Noted catch basin 10. 18-inch CMP Flows west from catch basin to 1 1,928-2,134 None Noted None Noted catch basin 11. 18-inch CMP Flows west across 1 2,134-2,174 None Noted None Noted 160th Avenue S.E. 12. 18-inch CMP Flows west from catch basin to 1 2,174 -2,304 None Noted None Noted catch basin 11778.003.doc See Map 13. 14. Type: sheet flow, swale, stream, channel, pipe. pond: size, diameter, surface area 18-inch CMP 18-inch CMP 'nrafollg~·component Description Drainage basin. vegetation, cover, depth, type of sensitive area, volume Flows west from catch basin to catch basin Flows west catch basin to catch basin Slope % 1 I Discharge Ft. Existing Problems Potential Problems Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring. bank sloughing. sedimentation, incision, other erosion 2,304 -2,458 I None Noted None Noted 2,458 -2,632 I None Noted None Noted Observations of Field Inspector, Resource Reviewer, or Resident Tributary area, likelihood of problem. overflow pathways, potenrial impacts 11778.003.doc TASK3 FIELD INSPECTION There were no problems observed during the resource review. Based on a review of the drainage complaints of the downstream drainage course, there were no existing constrictions or lack of capacity in the existing drainage system. 3.1 Conveyance System Nuisance Problems (Type 1) Conveyance system nuisance problems, in general, are defined as any existing or predicted flooding or erosion that does not constitute a severe flooding or erosion problem. Conveyance system nuisance problems are defined as flooding or erosion that results in the overflow of the constructed conveyance system for runoff events less than or equal to a IO-year event. Examples include inundation of a shoulder or lane of a roadway. Overflows collecting in yards or pastures, shallow flows across driveways, minor flooding in crawlspaces or unheated garages/outbuildings and minor erosion. Based on a review of the drainage complaints, there were no complaints associated with the downstream drainage course for this project site. However, there were complaints located on both sides of the downstream drainage course, to which this project site may contribute some runoff to under existing conditions; however, it was not likely. With the improvements of this project site, there is the potential that problems on both sides of the downstream drainage course may be helped somewhat by mitigating problems associated with those drainage complaints. Severe Erosion Problems (Type 2) Severe erosion problems are defined as downstream channels, ravines, or slopes with evidence of or potential for erosion/incision, sufficient to pose a sedimentation hazard to downstream conveyance systems or propose a landslide hazard by undercutting adjacent slopes. Severe erosion problems do not include roadway or minor ditch erosion. The sensitive areas folios indicated there were no erosion/sensitive areas in the downstream drainage course of the project site nor did the site visit find erosion problems evident anywhere along the downstream drainage course. Severe Flooding Problems (Type 3) Severe flooding problems can be caused by conveyance system overflows or the elevated water surfaces of ponds, lakes, wetlands, or closed depressions. Severe flooding problems warrant additional attention because they pose a significant threat either to health and safety or to public or private property. Neither the review of the drainage complaints nor the site visit noted any severe flooding problems in the downstream drainage course. Portions of the downstream drainage course investigated by the site visit and a review of the soils map indicates that the downstream drainage course occurs through till type soils. The field reconnaissance for this off-site analysis drainage report was conducted on the morning of October 27, 2005. The skies were partially overcast and the high temperature on this day was approximately 55 degrees. 11778.003 doc TASK4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Runoff leaves the site by discharging off the southern property line of the site where it courses through thickly forested areas with alternating trails for access to different portions of the site, and tends to sheetflow through forested areas into a seasonal stream that courses south and southwest into a blackberry bush area, ultimately discharging to a large channel, which may be a detention pond, adjacent to S.E. 144th Street, then flows are collected in an IS-inch CMP and catch basin pipe conveyance system, where it is coursed along the southern side of S.E. 144th Street for several thousand feet in a westerly direction until over 0.5-mile from the project site where the off-site analysis was tenninatcd. The drainage complaints are located on the following pages of this report; however, none of them were located on the downstream drainage course followed for this project site. They were placed into this report for reference only and, therefore, there are no anticipated problems associated with the development of this project site. 11778.003.doc NOV. 3. 2005 8:30AM KING CO. WLRD NO. 5845 P FILE COPY King County Water and Land Resources (WLR) Division 201 S Jackson St, Suite 600 Seattle, WA. 98104-3855 Date: FAX Number of pages including cover sheet: _fZ._ To: 0d}Jfj/J/ll2 Pax:. £'d'.£:-,£51-.frJ'2 Phone:--------- From: Candi McKay, Eng Tech II WLR Stormwater Services Section Phone:206-296-1900 Fax Number: 206-296-0192 IMPORTANT LEVEL 1 ANALYSIS NOTE: We do not send copies of certain complaint types that are not relevant such as BCW, FI, FIR, PIH and WQA, and we do not send CL and LS types, See key below. Type Sl; S2 and S3 will not be faxed due to size constraints. \ The following is a fu;t of complaint types received by the Water and Land Resources Division Drainage Services Section. Complaint numbers beginning prior to 1990-XXXX have been archived and are no longer in our possession. They can still be retrieved, if necessary, but will take additional ·time and · may not be beneficial to your research due to their age, development which has occurred, etc. If you are int.erested in reviewing the actual complaints, they can be pulled (time permitting) for your review . . ~opies can be obtained for $ .15 per page, and $2.00 per page for plans. Keys: • . Type of lnygtleytlon Type of Problem -C Action R«J11C>t DCA Bew Busines>'for c,..,, Water DDM CCF Response to J,,quuy DBS 'CL daim D~ EH Bnf~toxiHold. Dl"A ER Br>!oi=uou1-ew . INQ FCC,FcR.,FCS Facility Complsio" MMA Fl SWM Pee lnquiiy MMF FIil SWMPeeR .. iew MMO · Fill SWM Pee ou Hold. MMM •LS l.awsuit MNM '\ RR Facility Engineering Review MNW · NDA Ncagbl>od,oodDnllllag•-SW!' . WQc Wat«QualityComplamt WQB •,WQI! W•terQualityBufo""""""t WQD .' , WQR WaterQaalliyl!ngb,mh,iReview. WQI ',' WQA WatorQualityAu<lit REM > WQo WaterQuatity-Olhc, ORT ;\ Bl,82,SNJ Bugineering Soimoo NWD DeveJopment/Constructi.on Drainage .. M:iscellmeous Dtatlulge -J!roJion/SodimuulatioP • Drainage -Landslidelllorth Mo,anenl Dralnage Tecbnical Assistmce )?talnage -Cleoeral Inquiry ---Aeotbeti<s Main..,..ce-Flooding Maintcn,nco-Gcw,n,I Mainttmnce-.Mowing- MaiJtlODIDa:-Needs ldalncenanre Maintenmce-NQXious We¢s SWM Pee QueJtion, WBJ« Quollly-Best M>nagemom !'=<ices WaJtt Quality-Dumping WBJ« Qualily-llllcit Oanne<tion SWMFoe-~t SWM Fee-Onmt SWM Fet,.New Dm:ount COMPLAINT INVESTIGATION REPORT Ail ~/Jt#M fo 54J#IF/# ~ c2/~1 Sketch,onreverseside:Yes m No O Photos:Yes"" __ No o , /'-1 l"""\~ity c s~ Z.. '-Z-7-1! • /)JTCNES oJV ;u;,;e.:,/4 S"ll'JE op SI:: e A./Cl-o .s t:;0 / Z, ,i C!n,O -:, Ti/? R/:0 ou, Tc::) e!.<J .rr 12.-"· CP P4Jct;:O ,1f:-<J1,vsT fT 4S 5//otu,,___., /4..) Te~ ,,1.,,,0~.5 ~-r cf' P:etUtJc...,,Ay AT /6<l /0, PNo"R) @ ,)!cx,;.f A::>s-s:1r.;u; ~ 1v;,,.,,,,o t.v;;1cJ1 ,.,,.y ~ 71/c e-v7Z-1Jil.,C£ To -,J;J,S' , '-'"-' ,=..C Pi/'c, ,{.Jc, C-<:Jrc,,(I ~IA..I oZS,6'£!./EO /,v 7d1S C£lr:;ATt!o/V r($eA.,,,_,,,n& {:>1/'e JUAJ~ DATE: 2..,-z:E-'J f // ~ ll-·21 ''tu ~ ~ of action possible or taken by: Phone D Letter D Personal Contact o , , ndled By :&u::e :::.6,,,tJS'd),,/ Closed: OK'd: __ _ 1r,1llal!I o.,. NOV. 3. 2005 8:31AM KING CO. WLRD NO. 5845 P. 3 F 12.:x.. ~~I.J.. ~1t---V1-J\ · i;:,3: R ~ IS'(\-~ . -~=...:...._:_=------------S::UH-..,._,lff 11----0 M SIGNED SEND PARTS I AND 3 INTACT • PAU 3 Will IE RETUR>am Wfllf REPLY. ·----r ~ I i----'5E.. \ 44 'Tl-I. '5i ----a.- DATE "2 DATE POlY PAK 150 SETS) 4N72 WLRD,-----------NO. 5845-P. 4---- ·N Scale,~- J(,4/0. iZ,"cP / --------- oPl"'>ef PIP& Jo1,vf /,'.} 0 NOY. 3. 2005a ~).IArV1f~:,:,llNG CO. WLRD KmgCounty Su.dace Water Management Division · bep:ertment ofPublle Woi-ks Yes!.,-Building 400 Yesler Way ~ Room 400 Seattle, WA 98104-2637 (206) 2116-651~ April 8, 1993 Mr. and Ms. John McKay 16404 Southeast 143rd Place Renton, ·wA 98055 RE: Notice of King County Code Violation -SWM-DIR 91-0188 ~O. 5845 P. 5 Location: A portion of the northwest quarter (I/4) of Section 13, Township 23 North, Range 5 East, W.M. lying north of and adjacent to southeast 143rd Place between 164th Avenue Southeast and 165th Place Southeast. lot 32, in the plat of Serena Park, in King County, Washington. Dear Mr. and Ms. McKay: During an inspection of the property referenced.above on October 25, 1992, representatives of the Surface Water Management Division of King County's Department of Public Works found the enclosing of the roadside drainage ditch with substandard materials in the County right-of-way without the required per- mits and approved plans. This is a violation of King County Code Title 9.04.130; A drainage facility or construction site which: Adversely affects safety and operation of County right-of-way, utilities, or other County ownep and maintained property; and Results in dirt, mud, water, and/or ice on the roadway. This is also a violation of King County Code Title 14.24.010; . Road construction work which does not comply with King County Road Standards; and Title 14.28.020; Work within King County right-of-way without a permit and approved plans. You are therefore requested to contact Delite Koler, Drainage Investigation and Regulation Unit Engineer, at 296-1986 to discuss the correc- . tive work required to resolve these code violations. No drainage facilities, natural or manmade, may be altered or obstructed without prior permission. If you do not contact this Division within 20 days from the date of this letter, we may initiate appropriate enforcement action. This letter is not a Notice and Order as described in King County Code Title 23; however, the exis- tence of the violation noted above may subject you·tO civil penalties.and other methods of enforcement authorized by King County Code THle 23. 8:31AM KING CO. WLRD M and Ms. John McKay r. April s, 1993 page Two .NO. 5845~P. 6 ······--, .. ., ... -,{(JliJ) Your timely resolution of this violation will be appreciated. If you have any questions concerning this matter, please call Delite Koler, Drainage Investigation and Regulation Unit Engineer, at 296-1986. , sincerely, ;f µ~'Y/'4111~ ''.curt W. Crawford, P.E. :·Supervising Engineer, Drainage ) Investigation and Regulation Unit •. Chuck Kleeberg; Director, Department of Development and Environmental Services ATTN: Gary Kohler, Manager, Land Use Services Division Louis J. Haff, County Road Engineer ATTN: Tony Ledbetter, Supervisor, Maintenance Section, Division 4 Jim Kramer, Manager, Surface Water Management Division ATTN: Ken Guy, Assistant Manager Dick Thiel, Manager, Engineering and Environmental Services Section .s larry Gettle, Senior Engineer, Drainage Investigation and Regulation Unit Delite Kaler, Engineer NOV. 3. 2005 8:31AM KING CO. WLRD KingCoanty Swface Wat ... Management Oiv!sion DeparttnentofPubUc--h 700 Fifth A'Vtnue Suite .UOO Seattle) Vb\ 9610. <,ao&) 298-GStO (206) 28G-Ol.9/l FM February 11, 1994 Mr. and Mrs. John McKay 16404 Southeast 143rd Place Renton, WA 98055 NO. 5845 P 7 01,11 efi'ed £66[ '8 Lf.1dlf ~e~JW u~or ·sw pue ·~w RE: Notice of King County Code Violation -SWM -DIR 91~0188 Second Notice Location: A portion of the northwest quarter (1/4) of Section 13, Town- ship 23 North, Range 5 .East, W.M., lying north of and adjacent to Southeast 143rd Place between 164th Avenue Southeast and 165th Place Southeast. Lot 32 in the plat of Serena Park, in Ki·ng County, Washington. Dear Mr. and Mrs. McKay: .During an inspection of the property referenced above on FebrQary I, 1994, representatives of the King County Surface Water Management Division found that the substandard pipe that was installed in the right-of-way in front of your lot and tied into the drainage system has not been removed. This substandard installation is on the south and west sides of your lot. The fill that was placed in the roadside ditch also has not been removed and the ditch restored to the original design specifications. This is a violation of King County Code Title 9.04.130: A drainage facility or construction site which: Adversely affects safety and operation of County : right-of-way, utilities, or other County owned/maintained property: Adversely affects other drainage facilities; and Results in dirt, mud, and/or ice on the roadway. This -is also a violation of King County Code Title 14.24.010: Road construction work which does not· comply with King County road standards. \ You are therefore requested to contact Oelite Kol er, Drainage Investigation and , Regulation Unit Engineer, at 296-1986 to discuss the corrective work required .to resolve these code violations. No drainage facilities, natural or manmade, ·.may be altered or obstructed without prior· permission. If you do not contact Jhis Division within 20 days from the date of this letter, we may initiate appropriate enforcement action. This letter is not. a Notice. and Order as escribed fn King County Code Title 23; however, the existence of the violation .oted above may subject you to civil penalties and other methods of enforcement· .uthorized by King County Code Title 23. NOV. 3. 2005 8:31AM KING CO. WLRD Mr. and Mrs. John McKay February 11, 1994 Page Two NO. 5845 P. 8 Thank you for your attention to this matter. Your timely resolution of this violation will be appreciated. If you have any questions, please call Delite Koler. s;;erL/J ~r...;.,,, P.E Supervising Engineer, rainage Investigation and Regulation Unit CC:DK:ss C/WP6:LT24 cc: .Gary Kohler, Manager, Land Use Services Division Lou Haff, County Road Engineer, Roads and Engineering Division AIIN: Rod Matsuno, Operations Manager, Maintenance Section Tony Ledbetter, Maintenance Supervisor, Division 4 Jim Kramer, Manager, Surface Water Management Division ATTN: Ken Guy, Assistant Manager · Dick Thiel, Manager, Engineering and Environmental Services Section · Larry Gettle, Senior Engineer, Drainage Investigation and Unit f , Engineer ~ 3.2005 8:31AM KING CO. WLRD NO. 5845 p 9 Dcrs----. . KING COUNn' SURFACE WATER MANAGEMENT DIVISION DRAINAGE INVESTIGATION REPORT Page 1: JNVESTIGATIDN"REQUEST Type ~ Date: 1ql3,/9~ . OK'd by: [)~ Fue No. 9&-/ 7;) lj Received from: {Plea.ta print plainly for S-0:llnning), (Day) (Ev•) ---==J.!h""""""'"'vae--""'-'/'-'-ti_,__,,_,_it'""'10~L2'"""J _______ PHONE u?J?-fl5;;LJ __ _ "---'--'& ..... :2 ....... 0..,...(p ....... ·· _-__,_,/lo....,__,_,Y--'-"d,J'-""'-=a=w'-'---(~)/,=G"'--' _ City Yi~ State Zip f,/C5j_ don of probletn, if different; J •• --~Aaa,a_,~~ ~~~~'Y'-u~w~ ea/77~~(2,~1 Lot No: 30 Block No: / .· .•· d:3--23 _!£" 1 S T . R BasinJil.A_Y Council Dist ,Jg Charge No: J:: Citizen 'notified on/'6.;,./7fLby ._ phone_·_· letter -~in person ' Q;4.._ O"l ~ .. ~. .$.e..n_/ ~hfi-,. --k~ L,-I ~ i ~~ r -,_, ~ Turned to on by -----------OR: No further action recommended becaus, gency has bern. notified: has been corrected. -_:_:"N-:-o-p-ro'b'le-tn--:h-a-s'b-ee-n--=id-:-e-n""tif..-ie....,d,.... ------cP~ric-or-i-nv-e-st-lg-at-io_n_a_d-dr_es_s_e_s -pr-,oblem: -See File# • · · · roolem -NDAP will not consider because: ,'. -l(Water originates onsite and/or ori neighboring parcel ' _ LocatJon is outside SWM Service Area. , ED;__/!__; _jf; !f{_ by; .:11. , Nrl'RoA _ Other (Specify); NOV 3 2005 8 32AM KING CO. WLRD KiugCaunty Department of Naturnl Resources Surlllce Water Management DRAINAGE INVESTIGATION REPOR.T FlJ!Ll) 1Nv.ESI1GATI0N l'ltE NO 96-1724 NAME: GENE RlVAS ADDRESS: 14206 164TRAVESE !'HONE 2=24 MAINTENANCE 4 ~O. 5845 P 10 -~ -------"""'-- fflOMA& PAGE 6571l3 DATE 10-17-96 INITIAlS DCD \ - • I meet with Gene Rivas at his home to dillcuss his concerns about a _ ·oage problem in his backyard. Mr, Rivas property abuts up to a parcel of property o~ed by King nnty Parks that is undeveloped. Mr. Rivu property is saturated from the mnoff'from the Parks · perty, This water then gets under the Rivas house and into the driveway and into a catchbasin in the .,t of the Rivas property. I explained to Mr, Rivas that he shou1d contact a contractor le see about · g a French drain system. I said I would seµd a copy of the contracton list and a French drain . ' SATIJRATIID AREA J:. YARDDRAIN -. -.. 164fflAVI!SE . ...: SURFACE FLOws· J.- . t -+- NOV. 3. 2005 8:32AM KING CO. WLRD NO. 5845 P. 11 . ,;_ .. ,;KJNEt-eOui:nv suRFACE WATER MANAGEMENT oiv1Ste1f : 'DR.AlNAGE INVESTIGATION REJ;ORT !>age" f:·. INVESTIGATlON"ftEQUE~ . Typa . . oate: Ja 'f j' OK'dby: Flle·No. . . ~ ! /l .. --{; , ... ,,;Al . . ·., ~ •a,vvv-.-.... · · rc/ttvw :,.f-'l~ _· _ -ff/. 2-3 · ~ Paree! No. 7.2 t:; 376 -6/16 . s ~fl --' -· Basin .LC// · Councii Dist / :2 Charge No: 'lot No: · / / _ BlockNo': . No.Reid Investigation Needed __ _ (1d1161$! Th.Bros: New657tf 3 -Old 35FG:, Ji: Citizen notified onj..-J..0-9', by · .Jl phone letter _ In person . . ... G. ~ '--"llv~ .l'l'1A. ~ ~~ +,-·-' ~ ~ ~if~~~-. ·. -·. /JD4-.fR.. 't ~-ry) /I.A;}" ~l,..... . Tumedto {< 'onJ-;/:77.b; '~ OFI: NofurtheractlonreoommendedbecaL ' -gerioy has been notified: tias been .corrected. -_----'N-o-p-ro-bI-em_has_b_e-en-l~de-ntifi~. ~ecl.---_--Pn-·o-r lnv-es-tl-ga_ti_on_a_d~dr_es_s-.es-p.....,roble See Fife# • 1Proolem -NDAP will not consider because: · _ Wat.er originates onslte and/or on neighboring parcel --:. Location Is outs Ide SWM Service· Area. I ~ ~ • CED: .£.iu.14}~ by: .P...· ~ ..:._ Other (Specify): /. · · . b C.17.5/· NOV. J. 2005 8:32AM KING CO. WLRD Complaint 97-206; Don Gr~g, 16046 SE 142"" Pl., Renton Investigated by 'Sean Groom on 01114/97 N0.5845 P. 12 Don Gregg has li'Ved at the above referenced location since the early 60~ (his house was second built in the development). Surface storm water flows began flooding his garage approximately five years ago. At his own expense at that time he brought a back hoe in to cut a drainage ditch along the back side of his property. Tiris open trench provides relief during most preci:pitati011 events swface water mo-ves around his property. Stotm water does breech the top occasionally. The ditch fills sediments up and he clears the ditch of debris that floats down and reduces flow. He walks the drainage ditch during stm:m. events (he wasn't around for the last stonn event) to obset'Ve its functionality as a precaution as well. He wants the drainage to continue down 160"' A'Ve SE instead or a conveyance system around his and neighbor's property. Appaiently, as development north of his property has increased additional runoff is concenttated into the drainage along 160th A-ve SE and subsequently runs to his property. Standing water, nmoff:from 160°' Av,: SE discharges Into this area. Low percolation. Gregg said the land can't be developed because they don't have the percolation for infiltration of septic systems. SE 142nd Place ··. .,. ' l NOY l 2005 8: 32AM NEJ:GHBOlUIOOll llRAJ:HAOJ!l ASSXSTANCE P:RoCRAM (lmJU>) COMPLAillT EVALUATION MEMO DATE: 3-19-97 TO: l!'ILE FROM: Alan Meyera RE: NDAP EVALUA'l'ION FOR COMPLAINT NO. 97-0206 GRAGG 235-0168 16046 SE 142ND PLACE RENTON COMPLl!.:rNT CHRONOLOGY: ORIGINAL FIELD INV FIELD EVAL. OLD FILES: BACICGllOUND: 1-10-97 1-14-97 3-7-97 NONE BY SEAN GROOM BY /\LAN MB:ra:RS • Please see the attached drainage complaint investigation report dated l-14-97 by sean Groom. FDID:tlfGS: since the problem meets all of the NDAP project criteria listed below, it guaJ.ifies for and has been investigated under the NDAP program. • The'probletn site is within the SWM service area and doea not invo1ve·a King county (KC) code violation. • The problem site shows evidence of or reported localized flooding, erosion and/or sedimentation within the off road drainage system on private residential and/or commercial property due in part to later upstreem development. • The problem is caused by surface water from more than one adjoining property. SOILS: According to the KC soils map, the site is located in the following soil association, l\LDERWOOD ASSOCIATION: Moderately well drained undulating to hilly aoils that have dense, very slowly permeable glacial till at a depth of 20 to 40 inches; on uplands and terraces. ! met with· Mr. Gragg on Much 7th and toured his property. Aa development continues in the approximate 60 acre drainage baain north of his property, more drainage water has been routed south into the pond 0 l 0 cated just NW of his property which then drains ea.at and south around :the edge of his property. 1 .. . ' NOV. 3. 2005 8:32AM :<I NG CO. W', RD NO. 5845 P 1. 4 ~ --·--~---~ ---, __ He requ.ested that the drainage flowi.ng south along the east side of 160th Avenue SE be rsroutad straight aouth along the east side of 160th past SE 142nd Place rather than the current route which flows east and south around his property. Mr. Gragg stated that severa1 long term· residents have told him the drainage used to flow straight south along the weat and east sides of 160th all the way down to BE 144th. I stated that may be true but the existing drainage pattern is old and cannot be revised because it is considered the established drainage pattern for hie area. I reviewed his and hie two neighbor's drainage related impacts and scored the problem at 14 with his garage and septic system impacts and yard damage to two properties. A1though the l,;,st few years have been especially wet and bad, I rated the event frequency at 10 or once every 2-5 years which is my estimate of the frequency of how often his septic system will be severely impacted over the long term. Mr. Gragg stated that his pumped effluent aeptic Bystem has worke<:t fine for the first 15 years. Howe~er, he has burned up four pumps within the laat three years due to the increased groundwater flows into his septic tank/drainfisld area. From his wet/dry season observations, be is convinced that most of the groundwater comes from the drainage ditch located just above his drainfield. We reviewed ways of protecting bis septic drainfield from the movement of groundwater from the uphill pond and drainage ditch. We discussed ways to seal the earthen ditch itself using a plastic liner or a large half round or full pipe sections along about 50 fest of ditch above his drainfield. l pointed out that considerable groundwater may still flow from north to south below the ditch section so that sealing the ditch may not solve the problem. Depending on the depth to hardpan, an impervious vertical layer of plastic or bentonite slurry located uphill of his drainfield between his drainfield and the ditch would probably be the easiest and most effective solution to this problem. This impervious layer would run from the ground surface down to the hardpan layer where it would be keyed down into the hardpan layer. Because such a layer would restrict the flow of ground water, higher groundwater leve1s might result in this part of Gragg•s yard with more groundwater surfacing during the'wet season especially near each end of such an i,npervious wall resulting in more wet seaeon surface wa~er seepage/flows and icy conditions on portions of Mr. Gragg'e driveway. For any work this close to the drainfield, any yard drain or impervious facility of this kind would have to be reviewed and approved by the King County aealth Department (Wayne·Olsen at 296-9737). 2 NOY. 3. 2005 8:32AM KING CO. WLRD NO. 5845 P 15 ·-----h--~·-----:;;.v,; wgc; Min.. 4Jt l £ _ t PiiJJQQ ( &UL .OJ !J. OP~IOHS AND DISCUSSION Hr. Gragg is concerned about continuing upetraam development which typically results in more surface water fl._,.s through his drainage ditch and occasionally into his yard. l explained that for lai'ge,: . developments where more than 5,000 square feet of impe,:vious surfaces are constructed, the developer•a engineer is only required to review the drainage system's capacity·up to one quarter of a mile downstream from the proposed plat•e outlet point. For single homeaitee, there is normally no downstream analysis required since there is usually less than 5,000 square feet of new impervious surfaces constructed. I suggested that Mr. Gragg look for Development Signe along 160th north of his home. When he eeee new signs, he can attend public hearings and write letters expressing hLs concerns and outlining his drainage impacts. DIPAC'.r SCOIU!I = 140 PROPOSED SOLUTION: No solution to this drainage problem wae identified. Mr. Gragg requested that we clea.ii out hia drainage ditch. Wa offered to clean out part of his ditch if our contractor can get the necessary equipment from Gragg's driveway into the ditch. NO !:'KIO~ SCORE WAS CALc:tJLAmD SllrCE NO SOLUT:ION WAS lDENT:IF'Iffl> 3 .. ~-·---. -· '··---,..- Jct H.6:Sii NOV. 1 2005 _ 8:32AM KING CO. WLRD NO. 5845 P 16 . _. KING COUN'l'V WATER AND LAND RESOURCES DIVISION -D:RAINAGE INVESTIGATION REPORT lNVESTIGATIONREQUES'r · .fillCEJYED BY: FlLENO, 2005 -())-:M · ·Received from: ··AMB: ~·,/.JWz I . . -I - -(Day) ~f-~) /)dG90PHONE ------.-- (Eve) ,._( _ ___,) ~-.;_;__-------,---_;__--~City __ -,------State Zip __ _ yrf~~ :r Permission Granted O Call First (W-OUld Like To Be Present) D · . - CJ>~'kJ. ~-wi--"'~~ 11 lt~ pvito6~~ FIL: COPY Q~05SS Lot No: Block No: T. R Th.Bros: New (:£:1 63 Basin· l,,C,R_ Coll!lcil District /,& • City ___ Charge No. _______ _ Ci~n notified on ------by: __ phone __ letter _ in person Turned to on -/ / -by __ OR; No further action recommended becaus~: , ency h~ been notified: -- , _ has bee.n corrected. _ No problem has been identified. _ Prior investigation 0 ~ddresses problem: -. -SEEFiue# · . :ll!'Oblem -NDAP will not consider because: 1 Water originati;s oniite ruid/or on neighboring parcel. ~Other (Specify): I I By: __ _ NC'/. 3. 20051 8:32AM KING CO. WLRD NO. 5845 KING CoUNTYWATERAND LAND RESOURCES DMSION .. DRAINAGE INVESTIGATION REPORT INVESTIGATION REQUEST F. 17 Type C Date: {!; q 6 6' OK'd b : FILE No. 005 -df'3<j (Day) (Z.Ob} lJ1'coL6 ket.LEfZ PHONE Z-10-3 731 (Eve) ,._( -------') I( C :POT -IZµr;11vet({/~b City State __ Zip __ _ ·•• :110J1o_FPR0.BLEM, IF DIFFERENT: ~R:tt<JN;S tF Jl, Z. Avt: S { t lhf )vc S<:1 }Joli, oF 5~ ;tf sr. s Permission Grm,t.ed D ' Gilli First (Would Like To Be Present) D '' Lot No: BiockNo: , _T R 7 ' ··ParcelNo. /'fS?&OIJ/c/S Kron'('/ ( ' . Th.Bros: New 0S 7 ir3 Basin /;CJ{ Council District--1,./..,.j....__ City ___ Charge No .. _______ _ CitizeQ notified on -----~ by: __ phone __ letter __ in pe!'llon· Tumedto on -~/~~/ _ b:ir __ OR; No :further action recommended because: . cyhasbeenllot.ified: _______________________ _ · has beei:i corrected. _ No problem has been identified. _._ Prior investigation adtlresses problem: · · SEEFlLE#. ·---.roblem -NDAP will not consider beca=, ··• --Water originat!ls onsite and/or on neigliborin~ parcel. ~_Other (Specify): I I By: __ _ 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology The entire 9.91 acres of new development is considered till forest for pre-developed condition. However, there is an existing single-family residence located in the northwest corner of the project site, which will be demolished with this development. There is a small amount of impervious surface associated with this single-family residence that contributes runoff to the downstream drainage course under existing conditions. However, this site is modeled entirely as till forest for the pre-developed condition. The flow control facility will be located at the southwest corner of the project site and will discharge much as it does under existing conditions after being dispersed at the southwest corner of the project site. B. Developed Site Hydrology Under developed conditions, to determine the total amount of impervious surface contributing runoff to the pond, all of the streets and sidewalks were considered impervious surfaces and an area determined for all of them. Since this project site is zoned R-4, which requires that the maximum amount of impervious surface per lot be 55 percent, the total acreage of lots was multiplied by 55 percent to determine an impervious area for all of the lots. In addition, the wet/detention pond was considered to be impervious surface for the portion of the surface area of the wet/detention pond that is dead storage. This yielded a total impervious area of 6.37 acres with the remainder of the area as till grass (3.54 acres), totaling 9.91 acres of development. No Flow Control BMPs are included in these areas of development so the actual detention volume computed would be less in the final design when the Flow Control BMPs are applied to the project site for each lot. C. Performance Standards The Area-Specific Flow Control Standard required for this project site is Level 2 Flow Control, a.k.a. the Conservation Flow Control Standard. The applicable conveyance system capacity standard was mentioned in the Conditions and Requirements Summary, which is to size the on-site conveyance system by the Rational method utilizing an initial time of concentration of 6.3 minutes and a Manning's "n" value of 0.014 with the 25-year precipitation. The Area-Specific Water Quality Treatments Menu followed for this project was the Basic Water Quality Menu, and the item selected from this menu is to use the wet pond located below the live storage in the wet/detention pond. D. Flow Control System Please see the illustrative sketch of the flow control facility located the following pages of the report, as well as the calculations provided for sizing the flow control system for this project. E. Water Quality System Please refer to the same illustrative sketch referenced above, which is provided on the following pages of this report for the wet pond located below the live storage in the wet/detention pond provided with this development. In addition, the calculations for sizing the wet pond are included herewith. 11778.005.doc (JPlltep) [ g t -. ' I ' ' ! o, \--! ~ . :c ~ 0 OJ __ !(_ __ _ ~ ;~ ~ "'o'o ~~ -,,,-0 ·1 I / ;,:; ( .-_.../; ~--"1 2, 465.4 45'4.12 " i81.18 8 ~<9.0 4S.U4 IS6 < ' §, /5J9 8 4 2. & ' ' "'' "' ' I llffl:RaCTIOl'I ,. (IF ltOltO " $TA. l&+l!J.651 18215 72ND AVENUE SOUTH KENT, WA 98032 (425)251-6222 (425)251-8782 FAX CML ENGINEERING. LA.NO Pl.A.NNING, IOHJ'; / /~ -~ i ! SURVE'l'lNC, ENVIRONUENT•L SEIMGES Doto Ut~.i~ v,u'llool •I• I (.;,,~1 •,,.f •;NCI ' ' ~~-,...~~~,-,-----,-~/7_,---,,.~-i,,,- ' I • l! ,,. ; . 1• ,I j.' ~ ,_ ~{ '" 'I /8 ' ' / ' I ' y / 1;0.0~· '' ,,I.Tl,,'. 8. [f-''---~=~-....,: ~ ~ / / / ; / ( / 107. iii;' ~1~ " %1~ 8 4504 "'· 8 " ' ":Il 'lo C }> 0 <IHI ' :,, Hi, ~ ' ' C ,se.J 8 ~1. e -. t_ j '" ' ._, ' i 457 J ._, ;~6.1 45 .21 :; ·~9 9 8 -·-459_Q5 461 0 KBS DEVELOPMENT CORP. 12320 NE. 8TH STREET, STE. 100 BELLEVUE, WA 98005 } \ Tffle, " ~~ 7 g ~ 8 i ; ij " ,. ) g_ ' \ 8VCS: 10+-7~ \BVCt: +l,a.1~ ~S: IH25 \ PRELIMINARY ROAD AND PROFILES AND DRAINAGE PLAN FOR CAVALLA ' DETENTION POND SIZING CRITERIA No Flow Control BMPs were applied for this initial sizing; however, they will be utilized with the final design. Zoning = R4 The maximum allowed impervious coverage per lot = 55 percent Roadway and Sidewalk = 1.63 ac. impervious Pond = 0.19 ac. impervious Total impervious = 6.37 ac. till grass = 3.54 ac. 8.28 acres of lots x 0.55 = 4.55 acres impervious I 1778.005.doc [JPJ/tep] V, V, V, vb = = = = SIZE THE BASIC WET POND [0.9 A,+ 0.25 A,,] 0.039 [(0.9)(6.37) + (0.25)(3.54)) (0 039)(43,560) 11,243 cu. ft. 3 V, = 33,729 cu. ft. 11778.005.doc [JPJ/<ep] >, a ~ ~ J3 ·e ] :11 ff ! i!_u .. "· l • ~i ' ! s ., .. I ' g • 0 <" ' ~ BJ • l! ~ & ' ~ • ' • ; " 1 ~ i' = ~ • !j i i g : e, . ~ " !• 0 i JP ii ~ :I ;,. l' I I J • ~l j .'.l -2 ~ .r • • ! ;. jf 1! ~ : • • l J ; i ll J I I .. • j t • ii, ~· ~ :: ,, ~ ' u "' ~! ! ~ ! § !1 < ~l • ' 0 H \_ X D ' ~. Blf"l'"ll:WI I ' ?! ·-· . . , .... r. -. . Ji -/ \ -. C -~--" ~. -~ .... I ~ • I " ! ' • '\ ' .. .{,., §" , ~ . u " Jli...-.. u., ' J:~= " • '' r ~ • ) • "- ~ r ,• ? r . 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( a ~ .. • r ' • ;. •Y.,,;<l.ON n l • ~ _. ...... iE ' a i • ~ J ~ l • ;• ,sn .. -.• :JIS'o:l"'.U!,& • ., l ' • :JI-,:, ~.151 s~ .. 11u ~· ( \l i i! . < < ' ii i "~- • ~ • E! ' • • pt .! • >S3"¥Hlll;l f ~ • X"'lo><lllil 1J§ ~ • • j • ' ' ! J. .!i • • • ! }'Ci t . 'o"<, ! ~ • ' .jf ,c;,1-"t--,/ -------~ Jji 1 0 -~~ ,., . ' ;; ·~! • 0 ...... (l~· .,./·· ! ! >" ''I I / ,! • ISl!IOl'I.X t; 'j .... ~ iH$ ........ ' H , .... .r> • • ;; H!i ~ ! •J.W(l!O. i ; q/ :J"'l,O,¥A~ + • ' 11-,,.J.SaSI . HH § " ~ • ~ 1l- .l! " &! • i, ~ • i t ii :i ,{ i , i " • • .:, '·' ii ~ 1! ~ !I, 3 ,. i : • • J ~ • C • f j g • j u • ' ,x ·- '·,~ .. ~,t.· .. ! ' Inn, lo.,\,. 1,;,1,, ......... " . 1 • !!. ; ... " • . " • Ji j: il jf ~: l1 f 'i! E. .li .i D _)<_).•~I•)('"' -~ ~'-~' U•,I ' ' ~-,,1o.-,c·o"_ ,· ' ; ' Ji; ' • I .. i ~ • ~ ' • ~ J!, ~ ,!I i 1 • ~ . " ~ D ' • " ' ' • • J ; -'l ] . :5 ~ 'cl! r, :;l•'f bl,., F ' ' i • I ' • f. "]'S".,,.,y.,. • " l • • ' • • ' • ..... U?;, l!I ',r lSL~I • . , J • J5 .......... , ' ' ' ~ NO 120A.b -r\-115 SEC!10N1 ~ ~ ' 111 ,",_/ p ~ ~ ~- -~ ~ jGA~~~EDl .. . .... ·-1 ---1. ~ l,..-B.A'221E'~ • I i : ~ _(f--· ·r i I .. ., -~ : t ~ I , ; ! . t · .l_ · -· ··· SE 135TH Si!:!'EE"J'" LOCATION AN.Q 1)1£ECTIOJ:j ~1 TA1ZE!.'-l OF 17 PHOTD'S SUPPLIED . SE 13-qTit 'STJ;:EET' OPEN D£A1NAGE ·' I .... -uJ {/) w ~ ~ aJ <..9 ~ ;!:_.._f ;~! '~I L_ LL 1 4 \ -c'.. I j ~ i--··------T ,/ {-· \ 1.,445 r ----; :. ~0@-®-@ l.91() I , / · 113s,,,'<t : 1 .--: P.5 1 ! ® !.CA~E. j-----I ~ ~g ~-----i i \ I : : j/ ~ --- r:~ I I i , . --1 /, ·~ @\ ! \, ROAD 'cAl;:'2'iEli2 ..... / SCHOOL su·~ EXIT .,1-/ l BtfND f-1,FT"Rf.,1.:cr:. ---@ i I i I 1 ~-__ J I ' -~. --·····-·· -·-----·-·- I CORN'.ER ~ldG COT MC'ESS I ' I llBEl<TY 1-llGH SCl1COL ~ ';r' ! , 1.oof January 3, 2008 Summary of flow patterns over lower level of property at 16445 SE 135 Street, Renton WA, 98059 January I to February 15 water flowing February 15 to March water not flowing March I to March 2 water flowing March 3 to March 25 water not flowing March 4 to April 26 water flowing April 26 to April 29 water not flowing April 30 to May 5 water flowing May 6 to May 17 water not flowing May 18 to May 28 water flowing May 29 to October 31 water not flowing November I to November 18 water flowing November 19 to November 25 water not flowing November 26 to December 11 water flowing December 12 to December 20 water not flowing December 21 to December 31 water flowing. December 27 flow rate rough estimate 1200 gals per minute. Heaviest flow was December 22 no way to estimate flow rate, too wild for my rough estimating techniques. 2006 January I to March 28 water flowing March 29 to March 31 water not flowing April 1 to April 4 water flowing April 5 to April 8 water not flowing April 9 to April 24 water flowing April 25 to April 29 water not flowing April 30 water flowing May 1 to May 31 water not flowing June 2 to June 7 water flowing June 8 to June 12 water not flowing June 13 to June 16 water flowing June 17 to November 4 water not flowing November 5 to December 31 water flowing January I to April 11 water flowing April 12 to April 13 water not flowing April 14 Water flowing April 15 to April 16 water not flowing -• April 17 water flowing April 18 water not flowing April 19 to April 20 water flowing April 21 to May 4 water not flowing May 5 water flowing May 6 to November 16 water not flowing November 17 to November 24 water flowing November 25 to November 26 water not flowing November 27 to December 31 water flowing ( December 3 took picture of heavy flow included in letter under flooding comments) Compiled by John N Case, resident of property. 4254 271 3167 maja@comcast.net Comment; the goal is to install a proper system to measure accurately the flow across our property. Also a method of sampling the water quality. January 3, 2008 Hearing Examiner King County Hearing Examiners Office 400 Yesler Way-Suite 404 Seattle WA 989104 Fax 206 296 1654 RE: Threadgill Preliminary Plat Application L05P0026 Dear Mr. Examiner, We reside at 16445 SE 135 Street within 500 feet of the proposed subject Plat as referenced above. My wife and I have resided at this address since September of 1983. The Plat creates concerns of; traffic safety, increased flooding potential, unnecessarily increased taxes with no net increase in service value to our property, in fact a decrease in value generally, and potential health issues. Traffic Safety The only access to our property is along SE 136th street to 166 Ave SE and onto SE 135th street. Coming into the property you make a right hand turn around a blind corner. Because the no parking along this dangerous curve is not enforced, we are constantly in danger of meeting oncoming traffic as we attempt to adjust to the obstruction of parked vehicles in no parking spaces. The only fortunate aspect of our situation is that the traffic around this curve is very low, only the immediate neighbors, their visitors, delivery trucks and the postal service use this route. Should tbe 135th street be extended to pass the subject plat, the increase in traffic from Liberty High School and other vehicles finding, for various reasons, it a more convenient route will dramatically increase the danger of this curve. This is unacceptable for the increased personal danger you are subjecting our neighborhood to absorb. The solution to this problem is to make permanent the dead end character of 135th as it presently exists. There is another problem with extending 135th beyond 164th Ave SE. You would create a jog in the extension of 135th. In addition the jog would occur on a slope ( estimated at 20% grade) which would increase the danger already present by the jog itself. See pictures describing the traffic problems which presently exist. Increased Flooding The site of the proposed Plat is now heavily wooded. Our property is down stream from the plat. Heavy rains to some extent can be absorbed by this woodland. When houses and roadways and sidewalks are created in place of woodlands, the rapid drain off could cause surges of water to increase the flooding danger of our property. We see no adequate provisions in the plat to lessen this danger. The surge ponds described have apparently only one outlet each, which tends to focus the runoff. This is not the natural way the present wooded area would drain. Although they may absorb some of the initial surge from the total 4 acre drain problem this is counteracted by all the drain being focused at one point. We would like to see the arguments which support your proposal. The outlet from the eastern pond could overwhelm the existing downstream drainage system and spill over into our drainage problem. See Pictures attached of the flooding presently occurring over part of our property. We have also attached a three year summary of the drainage flow of water over our property. (2005, 2006, 2007) Increased Taxes Our area will undergo a new land assessment due to the new Subdivision created. The increased land value will increase our taxes. This subdivision will not result in an increase in the value of our property, for the reasons given above. Our area will be subject to increased traffic and potential greater flooding damage. The argument that, "well, just sell your property", is not realistic. My wife and I have spent 24 years paying off our mortgage; developing our land, home, shop to suit a retirement life style. "Life Liberty and the pursuit of happiness" as declared in our declaration oflndependence has been the essence of our goal and our faith that our government would support this goal. Our governments local, State, and Federal have deviated from this promise and seek only to increase their tax base. We may be forced to sell this property to support what appears to be King Counties unquestionable demand for tax dollars. Health Issues Created by Storage Ponds It has come to our attention by a neighbor who has relatives in Montana, that West Nile Virus has reached that area. It has caused two deaths and illness to others. The disease appears to be moving West. Because of this, I have drained a large outdoor fish pond that we had for several years. An investigation into the chemicals required to add to the pond to eliminate mosquitos were rejected as a solution. They were extremely poisonous and sounded more dangerous then my wife and I were willing to release into the local environment. These storage ponds that we see being used throughout the area in new subdivisions do not seem to drain completely. What is the risk of creating a West Nile virus condition in these ponds, which are located next to and surrounded by new family 2 living areas9 What assurance does King County give its citizens that this issue is being properly addressed9 Sincerely, Two concerned, long time residents, of King County ~f7,~ #u1·-a,~ John N and Mai A Case 16445 SE 135 Street Renton, WA 98059 425 271 3167 maja@comcast.net cc Gwendolyn High, President ofC.ARE. Threadgill Developement Erik & Michelle Hohlbein 16411 SE 135th Street Renton, Wa 98059 425-226-1615 206-407-7304 Our major concerns with the Treadgill Application: We are directly on the North East comer of the Threadgill property. The -propos~d retention pond is directly above our property to the west. Looking at plans for the retention pond it seems that the out flow will be running _girectly across our property and to the south west comers of both our neighbor's property. From accounts of all of our neighbors and previous complaints filed with the county our property used to have a pond on it that was filled to accommodate the house that we occupy. We are extremel concerned with having all the drainage run through our lot and the probability of flooding. We woul e to request that the deve oper find alternative ways to accommodate the drainage from their property. Attached to this letter we have provided drawings and annotated King Count Draina e Complaints that better illustrate our concerns. We also would like to request t e op ortunity to testify and provide more details at the Hearing on this matter, but neither of us has been able to get permission from our employers to attend when the Hearing opens on January 8th. We will be available on January 22nd. We apologize for any inconvenience and would very much appreciate any accommodation that might be made. e ........... \ I • I I I ) ,Q\a:-:---------~r.::. V -------------~1f!::!/ I\ ,, I I ,, I I ,, \u "' -~ I I \ I I \ I ,, \ I I ' ' ,, I 1 • I \\ --·-·-·-·-·-·-·-·-·-·-·-·--~~ ,, 1 '' . \ I 1 , ,. ,1 I \u ~'o .... ~ j~@ 'q, , l I ~ I 1 : '::! I 11 ! 11 .J ~ 11 1 • I I I ' I • 1 ' l I ' I l I ~© Ji NOV. 17. 2005 4:06PM i KING CO. WLRD CherlLee Kh,gt Coumy Public Works Drainage Investigation Sum: 1100 1111·3rdAve. Seattle, Wash. 9&101 Marcel C. G:ibeallb: 16115-ll!llh Ave. SE. Renton, Wash. 98058 Tel; 228-8411 Dear Ms. Lee KING COiJHrf SU!ITTCE WATER MANAGa,100 DIV!S!ON J.t has come to :my attenlion 1hat thero has been a. culvart illstal1ed across SE. 135th Stt. appromilldl'Jly 150 ft. East of the center of 164111 Ave. SE., pk,ase refer to your map SW 13-23•5. This oulvcrt does not show mt the original plo1s. lf the County installed 1hls culvert to drain the sudice water from 1he North side of SE. 135th S1r. onto our lot, thereby using our lot as a Reten&ion Pond 1hen the County should have to purchase it to do so. Jf 1his culvert does not shaw on your .RICOtds, we request :vou remove it mmtediately and 1hllt the property be reston::d to its original condition Your lim1: ami cooperauon in thiS mau« would be greatty appreeiatcd! Marcel C. Gibeault NOV. 17. 2005 4: 05PM KING CO. WLRD. -~· , • ... NO. 612 7 P. 4 AG.f;;;M~ T OIVl;:ilVN DRAINAGE INVESTIGATION REPORT Page 2: FIELD INVESTIGATION TYPE File Name: File No. Derails of Itive:s:tigatian; Date of field lnvestigatlon:""2./ .Li./ .l!. Related Investigations: Tlie area of concern is 1ow in relationship 111itl\ the surrot.mding preperttes, A re~atively sh;:i.11ow swale with drairiage from NW to SE h culvertecl under 135th and outlets into a l!'.lw Vil.cant lot. The x-c,!lW!rt outlet had rec,,ntly been <;lug out from surrounding soils and is 1ower than t'ne sons. A i-B is being constructP.d in the ditch in front of 16414-and is cormerted to the x-culVP.rt. There was no flow nr st.andina water at t!te tin::,. Photo l)·Looks ea~t on 135th. with ~iheau1t Jot on right. - Sketch: 2) Shnws r.s under construc~ton in dftoo, 3) Look~ nortnweste~~Y ~t ~ and concr~te o~t1et to CB. 4) ClosP up nf CB with connection to x-cu1vert. 5) X-culvert outl~t on so11th :side of 135th,. 6) Looks west on 135th with CB by mail l'iol(, - l' "(v· W, \1 I -© --'5'613:C+t,;;'. , •:.,: :ii: .ii,. ... NOY. 17. 2005 4: 07PM KING CO. WLRD COMPLAINT 95..0715 JOHNSON, JEFF lnVllstigated by Doug Dobkin,; on 9-15-95 NO. 6127 P. 8 Mr. JolmsQD. liad been an vanatlon thefimpart of Septi:mber and wanllld to wait until he got back to meet. We set the IIP1)0intmcDt up mt the 15th of Sepll:lllber. I ~ with Jdf and his Uncle onsite to discuss bis OODCttDs abaot dcwJage an 1his Jot he was :p=b.asing, Al:alllting to kffthe Coumy road =ws came mit and cfeancd t1II: dm:fles and expo,ied a cross Q.IWC/lt tl!ar 1uLd """'1 buried. 'Ille ~1Y ClllWS .topp,?bat 1hlo1'ight-af"Jt13)'wmtbe-wm:rwoou\4 o\lllel. 1 ~ 10 ldf itwouW. bellp mthe prop:rty mm«tn OOlrftlY tms '11'81Jor a=ss tMpraperty .in the .aamral drainage c:owse. We.bav<l had past · compto;ints O<l.1hi& pr~ £oi: ~ same mason. All the 1)revions. r:oniplalllts baVll been prtvS1e problems since it was the propctty owners IeSJl(lllSlol\y'to ,;omeytm: water from the CilJ6'I cu.lwit. l e:,gilalned to Jrff 0111.e this QLmllol was reop=d during c:onstroc1ion of his home that it wo-ald be his reponsibilty to main13ht the drai,nage system. closed file onsile with Ie!f Joboson. Call,idtwith t.}\bone munberfor a fflldentlal permit tech. ~, .. - .. ·~. ~: ~-···:\~·. ;-~~;-i \'· -~I15: "~!i~ ~"I " :~.1~,,~;;J:} ·-·~) /J} ·?< \}~; ·<1}~; FW: Inquiry: Accident reports request and a signage question Fr,J1-(1 :Scanlon, Jodi (Jodi. Scanlon@kingcounty.gov) IIYou may not know this sender.Mark as safe I Mark as unsafe Sent: Wed 1/02/08 2:55 PM To: highlands~neighbors@hotmail.com Gwendolyn, Please don't forget the following adjoinder that I am required to include. (And I am attaching a few minutes late for your enjoyment.) Thanks, Jodi Be advised that accident statistics and reports compiled or collected for highway safety purposes are not subject to discovery, are not admissible in any action for damages, and may not be the basis for opinion testimony in any such cases. See 23 U.S.C. section 409; Pierce County v. Guillen, 123 S. Ct. 720 (2003). From: Scanlon, Jodi Sent: Wednesday, January 02, 2008 2:49 PM To: 'Highlands Neighbors' . Subject: RE: Inquiry: Accident reports request and a signage question Gwendolyn, Here is your collision information. The information that I am providing is 1/1/2002 -12/31/2005 for each location. If the distance is O that means that the collision took place at the intersection (or relating to the intersection). OD means opposite direction, SD means same direction. The rest should hopefully be pretty clear. Please let me know ii you have any questions. Thanks, Jodi (206)263-6111 SE 128th St@ 156th Ave SE DATE TIME DlSTAN WE1\THER COLLIS LON TY!'!! STREE1' 1 STREET 2 Ul/20/2002 11:03 U Overcast Hight angle 156TIJ AVE SE SE l28'['JJ ST 01/22/2002 18·25 0 Ovrrcnst SD both :;traigh 156Ti I A VI•: SE SE 128TH ST 1U/22/21Hl2 19:10 0 Clcar/Partlv Cl OD om: 1t turn t56TI-I ,\ Vl\ SF SE l28Tf-l ST 12/23/2rnJ2 19:00 0 Ucar/!'art!}· Cl Right angk 156TH AVE SE SE 128TH ST 03/21/2003 13:02 ll Raining Right angk 15(/D-f ,\VI~ SE SF. 128Tfl ST 08/Hi/2003 20:10 0 Ckru.-/Panlv Cl Ven strike~ ti...-..: 156Tll AVE SE SE 128TLJ ST 08/24/21)1):'i 15:48 (J Ckar/Partl)· Cl Right angle 15c;1·1 ! :\ VJ\ SJ•: SJ:. !28'ff I ST 04/08/2004 17:28 U Cl('ar/L':mly Cl Right angle 15611[ ,\VF. SE Sr'. 128111 ST UK/! 1/2l!IJ4 17:2:'i O Cbr/l'artly Cl SD both straigh 156Tfl AV J,: SJ: Sl 1: 128TH ST 01/04/2()[15 9:45 O Clear/Partly Cl Right angle 1561'1 I AVE SE SE 128TfI ST 04/2S/200S 7:00 O Cl .... ar/Partly Cl SD bnth sLraigh 15(i"IH i\ VE SE SE 128TH ST 06/21/2005 17:20 0 Raming SD both straigh IS6Tf I AVE SE SI•: 128TH ST 09/29/2005 18:0IJ O H.;tining SD both strn.1gh 156TJ I AVE SE SJ•: 128TH ST SE 128th St@ 160th Ave SE D:\TE TIME DJSTAN WEXl"llEH. COLLISION TYl'E STRl(E"J' 1 STREET 2 0 I /02/2002 18:57 0 ( )vt-rca~r SJ) buth str~igh I c,()"J'f l ,\ VF SF SE 12WJTT ST 02/22/2002 16:20 0 Ovcrc;L~t SD both straigh l60TI l ,\ \IL·'. St·: SE 128"11-I ST 03/15/200212:()I)() ()vcrcasf ODoncltturn t60T£I.,\VJ,:SE SE128TH~-'l· 04/20/2002 15:3(1 O Ckar/l'artly Cl SD both straigh 16((f"JJ _-\ VE SF. SE 128"f'lJ S'I' 09/15/2002 15:20 !) Clcar/Partlv Cl ()l) <me' lt tum 160'1'1-! AV!·'. SI·: SI·'. 128'1'1-I S'J' 02/04/20037:45 0 Clcar/Partl~;CIRightrm,i;lic 16fn11AVESE SEtWTIIST 08/13/2003 20:20 O Ckar/hrtl1• (] SD one 11 tmn lW"JH .\ Vli Sli SE 128"1'/ l s·1· 06/22/2004 19:53 (} Ucar/l'n.rtl~-Cl ( )I) om.: lt turn 160TH :\ Vl' SI•: SI·: 128Tl I ST IO/J2/20U4 16:58 () Clcar/l'ardY Cl ()1) unc lt turn 1(,0TH AVE s1,: SE 128Tl I ST 11/(!5/20041 i:311 0 Clear/Partly Cl SD bilth maigh 160Tll :\ VI;, SJ,: SF. 128'1'1 I.:,;'\' 11 /0fl/2004 1 'J:27 O Fug/Smog/Smokc OD om: IL turn lGOTl l ,\ VJ-' SE SE 128Tf I ST 0 J /05/2005 9:14 O Clear/Partly Cl SD both stra.igh 1(,DTif :\ VF SE SF 128TI f ST 05/27/2005 15:41) (I Ckar/Parily Cl SD both ~traigh 160Tll :\ VJ( SE SE 12'1Tll ST 07/21/2005 13:18 0 Clear/l'artl1· Cl Right angk' 160"f!J ,\VE .SJ.i SL•: 128"!'l J ST Hl/19/200519:111) O,Trca:-t SDbothscraighl61JTl[AVFSE SEl28'111S'J' SE 136th St@ 156th Ave SE No collisions. SE 136th St@ 158th Ave SE No collisions. SE 136th St @ 160th Ave SE No collisions. SE 144th St @ 160th Ave SE DATE TL\1E l)!ST,\N \Vl•'.,\'l'HER COLLISION TYPE STREET 1 STREET 2 04/t 'Jnoo4 23:30 0 On::ru~t Vdi strikcB fi:,; JWTI ! ,\ VJ•: Sli ;"E 144Tl I ST From:smith5124@aim.com Sent· Sun 12/16/07 7:04 PM To: highlands_neighbors@hotmail.com I don't k~ow about 156th, but I was hit at the intersection of 136th and 158th. We were heading west towards 156th when a gal come from our left and hit us. That was Jan. 3rd before the stop signs were put up or- 136th. We almost got hit t:1.ere again last week when someone blew througn the stop sign. Be very careful there! ,, ® ... King County Department of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 Rlati1Sar,.e~ni m~ansmitta' RiieHrtiJ)la · y,J~t,~m!.11:lf;~tion q~1Qa1it~lla . Ll\!f§JlJ~~rr ... .",ijQ~f;'Jl.@if ·. L .! .· •· ·. )'( j t. .· J:,ate. 'Jig:i~tf~r;i·iijeciyij~i{,~,Yj~i,~09i ...... . ·1:>~idlige, .. ·. ··H~t1tjf!i«,r1:Qfttnlorjmati~fi~rmi.t'~gr2e, .,2007 Please provide ten (10) copies of the following, unless otherwise noted. Drainage: • Please resubmit the conceptual 162"d Ave SE offsite drainage/road plan to include an adequate shoulder on the west side. This will likely require tightlining of the existing feature along the west side of 162"d Av SE. Please also revise the drainage plan to show an existing 18-inch cross pipe under SE 1441 h St vs. a 15-inch shown on the original plan. The plan should also be revised to show a birdcage type overflow structure, where the east-west drainage swale enters the 162"d Ave SE RJW. • The onsite and offsite drainage plan should reflect Level 3 Flow Control (or other proposed mitigation) as suggested in the Level 3 Offsite Analysis submitted. • Please provide an analysis and estimate of compensating storage required for the existing depression north of the SE 1441 h ST cross culvert. • Revise the conceptual drainage plan to include any compensating storage, Level 3 Flow Control or other revisions necessary. • Please revise the conceptual drainage plan to address 3: 1 length to width ratio for the water quality design of the facilities. Note that baffles cannot be used to obtain 3:1 per Section 6.4.1.2 p6. 6-73 of the KCSWDM. • Please show how the access requirements and grate requirements for the off site 162"d Ave SE Vault are to be met If the requirements are not met, a drainage adjustment may be required. • For any questions on the drainage items please contact Senior Engineer, Bruce Whittaker at 206-296- 7211. Revised Preliminary Plat: Provide 25 copies of a revised preliminary plat, as necessary, as a result of above-referenced requests for additional information. Please also include 3 copies of the revised site plan on a reduced 8 W' X 14" page. As a result of the review of the information, additional information (studies, revisions, etc) may be requested at a later date. Further evaluation of these issues may result in the reconfiguration and/or loss of lots. Cavalla -L06POOO 1 07/07 King County Department of Development and Environmental Services Land Use Services Division Attn: Mr. Chad Tibbits, Project Manager II Current Planning Section 900 Oakesdale Avenue S.W. Renton, WA 9055-1219 RE: Resub 1 · nal Information Plat of Cavalla King o 1 e No. L06P0001 Our Job No. l 1778 Dear Mr. Tibbits: CIVIL ENGl~Jff"ll"JG. I AND PLANNING. SURVEYlt~G. EM\ilFiONME\lTAL Sl::RVICCS November 20, 2006 I am enclosing the following documents for your use in reviewing and processing the preliminary plat of Cavalla. 1. Ten (10) copies of the Traffic Impact Analysis dated October 31, 2006, prepared by DN Traffic Consultants 2. Ten ( 10) copies of he 162nd Avenue S.E. extension plan prepared by Barghausen Consulting Engineers, Inc. 3. Twenty-five (25) copies of the revised preliminary plat map, road, drainage, adjacent property owners map, and tree retention plans. The following is a response to the May 11, 2006, Plat Screening Transmittal letter. A brief response to each issue (in order) from the Plat Screening Transmittal is provided below: Drainage: • Please revise the conceptual drainage plan to show detail of how the proposed drainage facility will outfall to the south. The plan submitted appears to show dispenal across the proposed sidewalk, which is not an acceptable discharge design. Response: The discharge of the storm pond (Tract A) on Sheet C2 indicates the connection of the storm drain outlet to a proposed storm system in 162nd Avenue S.E. The improvements to 162nd Avenue S.E. are to be extended as part of the proposed plat of Liberty Gardens (King County File No. L04P0034). If the plat of Liberty Gardens is not developed, the discharge would be designed as a sheetflow separator to the extension "" '''"" "'"~ S.E. 00 @: © @: D w @:@ MAIN FILE COPY 1821 S 72ND AVENUE SOUTH BRANCH OFFICES + OLYMPIA, WA NOV 2 2 2006 King County Department of Development and Environmental Services Land Use Services Division Alln: Chad Tibbits, Project Manager II Current Planning Section -2-November 20, 2006 • Please show how the 3: I length to width water quality ratio is to be achieved in the drainage facility. Response: The storm drainage and water quality pond is revised to provide a baffling system to meet the 3: I length to width ratio. Traffic/Roads: • The Subdivision Technical Committee has noted in our review to date that an evaluation of the impacts of the three pending plats: Cavalla (L06POOOJ}, Liberty Gardens (L04P0034) and Threadgill (L05P0026) will have an impact on a listed High Accident Location at the intersection of Southeast 128th Street/162nd Avenue Southeast. Response: Please attached Traffic Impact Analysis (TIA) prepared by DN Traffic Consultants for the plats of Threadgill/Cavalla/Liberty Gardens dated October 31, 2006. • The STC wishes to advise you that potential mitigation that appears to be feasible and capable of being accomplished is available to address the cumulative and significant impacts of your proposed development and the other two pending plats cited ( Liberty Gardens and Threadgill). This mitigation would include an extension of the frontage improvements fur the plat of Threadgill easterly from 164'' Avenue SE to the intersection of 166'' A venue SE. Response: In a combined effort with the developments of Threadgill/Cavalla/Liberty Gardens, Barghausen Consulting Engineers, Inc., surveyed the unimproved right-of-way of the potential extension of S.E. 136th Street east from the plat of Threadgill to the existing road improvements near Liberty High School. Additionally, as an option of the three developments, we also surveyed the unimproved right-of-way of 162nd Avenue S.E. from the southwest corner of Liberty Gardens to S.E. 144th Street. Barghausen Consulting Engineers, Inc., then requested that Chad Armour, LLC, locate any environmentally sensitive areas within the right-of-way of both options. With this information, Barghausen Consulting Engineers, Inc., prepared preliminary road designs and profiles to determine the potential for a road extension for a secondary access for all three projects. We then met with King County to discuss these options. Based on the fact of topography, grades, and sensitive areas and for the fact that existing right-of-way does not exist for the complete roadway section, it was determined that the preferred option for this project is the extension of 162nd Avenue S.E. to S.E. 144th Street. The 162nd Avenue S.E. extension also has sensitive areas; however, based on our design, we believe they can be mitigated. Furthermore, we believe that this access provides a better alternative secondary access for this area. King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -3-November 20, 2006 • This would also appear to address issues of school walkway safety ( RCW 58.17) to Liberty High School and Briarwood Elementary. This connection provides access to a currently-signalized intersection of SE 128'h Street/J6<Ji' Avenue SE. Response: As required by King County DDES, we have designed the plat to provide on-site sidewalks as well as access through the proposed park (Tract B) and through a l 0-foot pathway serving Liberty High School. It is our understanding that the same requirement is required at the plat of Cavalla. This access will provide safe access for the high school students being served by Liberty High School. We will need to meet with the School District and determine if openings to the existing fencing surrounding the high school would be appropriate. • This potential environmental millgation will be further evaluated during the traffic review of each the other two plats currently being reviewed, as well as this project. A similar request is being made of the Applicants for the Cavalla plat and the Liberty Gardens plat. Response: Comment noted. A TIA for all three projects (Threadgill/Cavalla/Liberty Gardens) has been prepared and is enclosed with this resubmittal. • In order to review the proposed project, please provide a conceptual frontage improvement plan for SE 136th Street (plan and profile) --extending easterly between 164th Avenue SE and 168th A venue Southeast. 11,is extension should be designed to the standards for a Neighborhood Collector, and the plan view should include any required retaining wailslrockeries/slope grading in addition to the roadway improvements consisting of a curb, gutter and sidewalk section, a minimum of 22 feet of paving, and associated stormwater facilities (culverts) and detention/treatment. A full 60-joot wide right-of-way extends through this segment, except for parcel located on the ( if extended) southeast corner of the 164th Avenue SE/Southeast 136th Street intersection. There appears, here, to be a JO{oot wide right-of-way on the north side of Southeast 136th Street and a roadway easement (also 30-feet in width) on the south side of the 'centerline' of' this roadway. Response: As discussed above, we have analyzed both sections and provided conceptual profiles to King County. Also, Mr. Curtis Schuster met with the property owner of Tax Lot 1323059039 (Lovegren) to discuss the potential of obtaining additional right-of-way for the extension of S.E. 136th Street. Mr. Lovegren indicated that he really did not want additional traffic across his property and that any further proposals he would need to discuss with this attorney. Based on this information as well as further research in this area, we determined that the preferred option is the extension 162nd Avenue S.E. to S.E. 144th Street from the southwest comer of Liberty Gardens. Therefore, we have enclosed ten ( 10) copies of the proposed alignment, road improvements, and profiles. King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -4-November 20, 2006 • In order to determine the precise roadway section required, and walkway improvements needed, please provide a Level 2 TIA. This TIA should include an assessment of the cumulative impacts of the three pending development applications (Threadgill, Cava/la, and Liberty Gardens), the volume of impacts at the HAL at Southeast [28th/160th Avenue SE, and any additional non-project traffic ( Liberty High School and existing developed lots in the vicinity) that would reasonably be expected to travel on this section of Southeast 136th Street. Include impacts and levels-of'service (AM and PM peak hour, during the school year) at (at least) the following intersections: 156th Avenue SE/Southeast 136th Street, 169th Avenue Southeast! Southeast 128th Street Southeast 136th Streetll 60th Avenue Southeast Southeast 128th Street/I 56th Avenue Southeast Southeast 128th Street!J60th Avenue Southeast Response: We have enclosed ten (10) copies of the Level 2 TIA prepared for the plats of Thrcadgill/Cavalla/Liberty Gardens that addresses all of the intersections referenced above and the high accident locations. • In addition, the proposed project may have a measurable ( I or more peak hour trips) at a High Accident Location (intersection) at the intersection of State Route 900/ 164th Avenue Southeast. Please include, in the TIA, an assessment of the project's impacts (number of peak hour trip-ends, only) at this location. Based upon the impacts of the developmem at that location, a requirement may be imposed to financial contribute (reimbursement) towards reduction of the impacts of the HAL (signalization at the intersection of 148th/ SR 900) via signalization being jointly funded by other developments in the area. Response: As indicated in the Level 2 TIA, all three plats will be required to pay an MPS mitigation fee and a pro rata share of the cost of the improvements at the 148th Avenue S.E. and SR-900 intersection. Additional road comments: I. KCRS Section 2.09.4 requires that the roadway to which an alley (Tract "C") connects shall be a minimum of 28 feet in width (i.e. the Subcollector standard), with vertical curbs. Please revise Road "A" to comply with this requirement. Please revise the design ofthefromage improvements to 162'd Avenue SE to comply with this requirement. Response: As required by King County, we have made the appropriate revisions and provided the minimum of 28 feet of road width. 2. Please provide a conceptual plan for an alternative design for the south half of the proposed project (the parcel upon which was proposed the preliminary plat of King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -5-November 20, 2006 Dickenson) that provides a public street connection between this plat and the proposed plat of Liberty Gardens, and terminates Road B with a temporary turnaround. Response: This comment is no longer applicable since we are proposing the extension of 162nd Avenue S.E. to the intersection of S.E. 144th Street. Therefore, a turnaround is no longer applicable. 3. Alley! Tract "C" Alleys should have a straight cross-fall, or, normal crown section. Please revise, and adjust the conceptual drainage plan as necessary. Please revise the design near the NE corner of proposed Lot 34 to accommodate the low-speed curve requirement from KCRS 2.10. Please provide verification that 150 feet of stopping sight distance will be available through the entire length of the alley -in particular at/near the curve abutting the NE comer of Lot 34. Response: We have added a 150-foot stopping sight distance triangle to the plan to show this requirement can be met. 4. Please provide a Traffic Impact Analysis to address the impacts of the proposed development at the following intersections: • • • SE 1281h Street/16(/h Avenue SE SE 1281h Street/156" Avenue SE SE 1361h Street/156'h Avenue SE Response: These intersections have been addressed in the Level 2 TIA prepared by DN Traffic Consultants dated October 31, 2006. S. Please revise the site plan to show a temporary turnaround at/near the southerly end of 162"" Avenue SE. Response: A temporary turnaround is no longer needed for this project because the plat will be required (along with the plats of Threadgill and Liberty Gardens) to extend 162nd Avenue S.E. to S.E. 144th Street. Critical Areas: • Please demonstrate that buffers being used to protect off-site wetlands are correctly using the current King County Critical Areas standards located in KCC 21 A.24. To King County Department of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -6-November 20, 2006 Contact Nick Gillen, Senior Ecologist with questions regarding this requirement at (206) 296-7141. Response: As part of the extension of 162nd Avenue S.E. for the plat of Liberty Gardens, the impact to a wetland and buffer will be mitigated and, therefore, will have no impact to the southwest corner of this project. As part of 162nd Avenue S.E. improvements, a mitigation plan will be prepared for that project. Recreation Space.' Submit a conceptual recreation plan that indicates the type of improvements (i.e. sport court, play strncture, benches, landscaping, etc.) proposed within the recreation tract(s). See KCC 21A.14.180(E)(2)for equipment requirements. Response: Please find enclosed the preliminary plat landscape park plan as required by King County. The park provides two play structures and meets the required park area. See Sheet PLl of 2. Conceptual Significant Tree Retention Plan (Mitigation); Submit a conceptual significant tree retention plan and/or a mitigation plan for the plat. Response: Please find enclosed the significant tree retention plan based on King County requirements. As required by code, we must provide 89 replacement trees. We are proposing to save five trees on site. Walkways: Provide an inventory map (i.e. existing conditions ~ widths, su1ace type, etc.) of the walking routes to the elementary, middle school/junior high, and high schools and/or the appropriate bus stop location associated with each school. Identify any improvements necessary to provide safe walking conditions. Response: An inventory map is not required because all grades (elementary and junior high school) are bused. However, high school students (Liberty High School) will get access to the school (which abuts the plat's east boundary line) via a JO-foot pathway (Tract C). Proof of Legal Lot: No proof was submitted that this is a legally segregated lot. The underlying 1907 plat did not create legal lots. A deed for the parcel in the present configuration dated prior to October 1, 1972 or tax records prior to 1972 with the parcel in the current configuration were not submitted. Response: On May 26, 2006, we provided this information to you from our title company. However, we have also enclosed additional copies for your review and approval. King County Depanment of Development and Environmental Services Land Use Services Division Attn: Chad Tibbits, Project Manager II Current Planning Section -7-November 20, 2006 Revised Preliminary Plat,' Provide 25 copies of a revised preliminary plat, as necessary, as a result of above-referenced requests for additional information. Response: As required by King County, we are providing 25 copies of the preliminary plat of Cavalla, preliminary road and profiles, and drainage plan, adjacent property owners map, tree survey map, off-site extension plan for 162nd Avenue S.E., preliminary park plan, and significant tree retention plan. I am confident that the enclosed information provided adequately addresses the Plat Screening Transmittal letter dated May 11, 2006. If you need additional information, please contact me. Respectfully, s.a ex!! aJa,,,~+ri1e1er- GWP/tep l l 778c.006.doc enc: As Noted cc: Mr. Bob Ruddell, KBS III, LLC Mr. Kolin Taylor, KBS III, LLC G. Wayne Potter Project Manager Mr. Curtis Schuster, KBS Development Corp. (w/enc) Mr. Daniel K. Balmelli, Barghausen Consulting Engineers, lnc. Mr. Ali Sadr, Barghausen Consulting Engineers, lnc. LelJ!lnd -1 I_ County Bo@<l.ary Streets Parcels Contours [5ft light) lhghW")' D Parks 100;~:1000 """"""' Sh.aded Relief Other LoQI Highways D Lakes and Large Rivers ;./ Incorporated Area ,/'·'· Streams The iniorma1ion included on thr3 map has been compiled bY. King County staff from a vanety o1 soun::es and is suUJeCL lo change without noUce. Kmg County ma~es no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or ri_ghts to lhe .use of such 1nformat1on This document 1s not m1ended for use as a survey product. King County shall not be liable ior any general, special, 1nd1rect, 1nc1dental, or consequential ti K" C damagoo 1nclud1ng, ,but not 11.m1ted to, lost revenues or lost prolils resulting tram the use or misuse of 1he information contairied on t11is map. A.fly sale _of ' 1ng ' ounty this map or m/ormat1on on this map is proh1b1ted except by written permission of K1rig County. Date: 12/31/2007 Source: King County IMAP" Property lnfarmafon (http://www.metrokc.gov/GIS/1MAP) March 18, 2007 John & Nenita Chin , 16038 SE 142°d Place Donald & Andrea gg, 1604'.SE 142°d Place Norm & Patricia G ell, 16043 SE 142°d Place Renton, WA 98059 Ed McCarthy, Ph.D PE _ Haozous Engineering P.S. 9957 171" Avenue SE Renton, WA 98059 VIA: CERTIFIED MAIL Dear Dr. McCarthy: It has been nearly a year since we brought to King County our concerns about excess surface water running into our properties. There has been an unprecedented volume of water passing through our properties because of development north of our homes. The volume of water passing through our properties has beeii constant and is causing deterioration to our land. This letter serves to inform you that, because King County has not fixed the problem of excessive surface water flowing through and into our properties and the adjacent undeveloped King County right-of-way, and in order to protect our homes, we will be installing drainage pipes, and contemplating other options as well. Yours truly, Owners of property located at 16038 SE 142°d Place: Owners of property located at 16031 SE 142°d Place: 'tC. ~~tnwn Owners of property located at 16043 SE 142°d Place: fba;:J rld .// ;{]p,_//j/l; /'-,,IV(, .( 'Patricia Gammell '° rn D u-, er u-, ru D .:r D D D D rS '° D .1l U.S. Postal Servicer.. CERTIFIED MAIL. RECEIPT (Domestic Mail Only; Na Insurance Coverage Provided} For delivery information visit our website at www.usps.coma SEAI/LE:';"IJA 98104 C l ;J. I ----- Postage $ $0.39 -0267 -- Certifled Fee $2.40 14 . Postmark Return Receipt Fee Hom (Endorsement Aequired) $0.00 -< .. -- Restricted DeHvery Fee {Endorsameni Required) $0,00 ---- Total Postage & Fees $ $2w 79 -0J12t12007 g Sont ' 06ht1.1N/ dR,rt{Y«d! -1;Jt1w ZI "-">K &:,/',lY/:.t::O f'-~:~·::xl::·:m~•~•inm6• JAckst,1 df- u, .:r D u-, er u, ru D .:r D D D D rS '° D .1l I C/ty, Stato,ZJP,,< c7{lil//l, tu A 1a JD 1-o3'65 PS Form 38011, June2002 See Reverse for Instructions U.S. Postal Service,. CERTIFIED MAIL,. RECEIPT (Oomestic Mail Only; Na Insurance Coverage Provided} .,, -·-.t"""''-'.1 C hl A. l l! s i1= ti/A"°~ ~ -, .... Postage $ $0.39 -0267 - Certified Fee S2.40 -!4 Return Recelpt Fee Postmark (Endorsement Required) $0,00 . . -- Hem Restricted Delivery Fee ,t :, .... · - (Endorsement Required) $0,0Q_ ,_ $'"' '->: '" Total Postage & Fees $ .!... 79 -..< 03/21,'2007 ~- Cl Sant To Ci f/i ~ ;;o:;;-;:;:;:,1~5 :~~;-ti~;uo_G~i~ city, srato, ZIP+4 /'tr,/1,,, µ),/ 1 JD v'f PS Form 3800, June 2DD2 See Reverse lor Instructions I DEVELOPER'S LIMITED USE PERMISSION FOR TEMPORARY CONSTRUCTION ACCESS THIS LIMITED USE PERMISSION is made this /9'.!iJ day of /11~ , 2004, by and between Donald 8. and Andrea Gragg ("Property Owner"), and S Development Corporation ("Developer''), and/or assigns. Donald B. and Andrea Gragg are the legal owners of that certain real property known as Tax Parcel Nos. 725370-011 O and 725370-0120 known as Lot 11 and Lot 12 of Rich Lea Crest located at 16046 S.E. 142nd Place and 16042 S.E. 142nd Place, respectively ("Property"). KBS Development Corporation is the developer of a plat known as Hamilton Place (King County Project No. L02P0011), located between 158th Avenue S.E. and 160th Avenue S.E. As part of the development of Hamilton Place, King County is requiring repair and improvement to existing drainage facilities as shown on the attached Exhibit A based on the approved Sheet C13 of 13, Downstream Drainage Improvement Plan. Property Owner hereby grants permission to Developer and/or assigns to enter onto the real property described above under the following conditions: J___.-------- 1. Term: Unless otherwise terminated<Q~~~ 'lh!0terms hereof, the term of this permission is from June 1, 2004 until Qetebe,:: 1, 2004. This temporary permission shall utomatically terminate upon completion of all improvements for the plat of Hamilton Place (King County Project No. L02P0011), in the event such completion occurs prior to c0elielaer1, 2004. l>eif .... ~ 2. Developer's Use of Property: Developer's use of the Property shall be for access to implement construction of improvements for the plat of Hamilton Place. 3. Restoration: Upon termination of this permission, Developer will restore the surface of the Property to a condition as good as or equivalent to its condition prior to entry by Developer, except that Developer shall not be required to replace trees removed within the Property. Developer will exercise its best efforts not to damage any private improvements on the Property, but if it does so, it shall repair and/or replace said improvements. EXECUTED as of the date first above written. Andrea Gragg, Propertyner Gragg Construction Permission Ur STA TE OF WASHINGTON COUNTY OF J{1J'<] ) ) 55. ) On this N DJ day of /}1 ~ , 2004, before me personally appeared Donald B.' and Andrea Grag~to~e known to be the individuals described in and who executed the within and foregoing instrument, and acknowledged said instrument to be the free and voluntary act and deed of such parties for the uses and purposes therein mentioned. Signature of Notary Public Dated Residing at Ktt'Kt e/JJ/IJ Appointment Expires: 5( · 3 0 · OS Gragg Construction Permission Ur I ,~~~POSED 60' WIDE UNOPENED R W FOR 1 62ND AVE S.E. (Af'PRDX. LOCATION ONLY) REGRADE EX. DITCH TO TO ACHIEVE A 1 1 /2: 1 MAX. SIDE SLOPE. 1 1/2.1 (TYP.) ~t ~-----=..'.6~~ ~ ?__ ~ -' <1~ --7-UO.j,___ . __.,,;=..~1 / / \/ I \ •16.0 -U'Ji.i,. ----------,e,------~' ~~ -----;-r WALi.. ~15.C .-,. --- 60 -~~ 2 -•• ~=t---- / I / / u-J ----'~ CONCRETE CULVERr O 2.33~ PROPOSED TOE OF SLOPE ----------- /// ,/~LOT LINE (Af'PROX. LOCATION ONLY) NOTE: CONTRACTOR AND/OR DEVELOPER SHALL COORDINATE WITH PROPERTY OWNERS OF LOTS 11 AND 12 PRIOR TO BEGINNING CHANNEL IMPROVEMENTS. .';·_::.. ::)-~ ·;-;::.:;,,," -------.-• NOTE: ARMOR DITCH WITT-I 6" TO 8" QUARRY I SPAll.S WITH A I THICKNESS OF 12"' I I ...,,.-EX. TOE OF SLOPE /EX. TOP OF SLOPE ' 4(/; 408 ~ I i 'I I ~ i EX. CHANNEL IMPROVEMENT PLAN SEEKEY MAP FOR LOCATION ADDmONAL INFORMATION DOWNSTREAM IMPROVEMENTS. ® k.l.'\C; ( Ol","\"I\ Bruce Whittaker Senior Engineer ~ Land U Services Division - Dep nt of Development and Environmental Services 900 0a e Avenue Southwest Renton, A 98055-1219 (206) 296-7211 FAX 296-6613 TIY 296-7217 E-mail: bruce.whittakcr@metrokc.gov ·;";,.--_;.. ·· DEVELOPER'S LIMITED USE PERMISSION FOR TEMPORARY CONSTRUCTION ACCESS I </11:! /!" ,il-, THIS LIMITED USE PERMISSION is made this day of 1 , 1 n "' , 2004, by and between Donald B. and Andrea Gragg ("Property Owner"), and ~S Development Corporation ("Developer"), and/or assigns. Donald B. and Andrea Gragg are the legal owners of that certain real property known as Tax Parcel Nos. 725370-0110 and 725370-0120 known as Lot 11 and Lot 12 of Rich Lea Crest located at 16046 S.E. 142nd Place and 16042 S.E. 142nd Place, respectively ("Property"). KBS Development Corporation is the developer of a plat known as Hamilton Place (King County Project No. L02P0011), located between 158th Avenue S.E. and 160th Avenue S.E. As part cf the deve!opment cf Hami!tcn Place, K1ng County !s requiring repair and improvement to existing drainage facilities as shown on the attached Exhibit A based on the approved Sheet C13 of 13, Downstream Drainage Improvement Plan. Property Owner hereby grants permission to Developer and/or assigns to enter onto the real property described above under the following conditions: 1. Term: Unless otherwise terminated pursuant to the terms hereof, the term of this permission is from June 1, 2004 until October 1, 2004. This temporary permission shall automatically terminate upon completion of all improvements for the plat of Hamilton Place (King County Project No. L02P0011 ), in the event such completion occurs prior to October 1, 2004. 2. Developer's Use of Property: Developer's use of the Property shall be for access to implement construction of improvements for the plat of Hamilton Place. 3. Restoration: Upon termination of this permission, Developer will restore the surface of the Property to a condition as good as or equivalent to its condition prior to entry by Developer, except that Developer shall not be required to replace trees removed within the Property. Developer will exercise its best efforts not to damage any private improvements on the Property, but if it does so, it shall repair and/or replace said improvements. EXECUTED as of the date first above written. Andrea Gragg, Propertyner Gragg Construction Permission Ltr Threadgill Plat Concerns I ,11nkc almost kwel.. • .t ·tt ·· y " ._ -~C -1 --_ _., .. ,. ,)I ' '·-~ ~ iJ / l :ft ~ { 5t.lt, 1 ~-~...,,,_;,1- I / -.... "'·~ ' CASCADE WATER ALLIANCE Final Environmental Impact Statement Tacoma-Cascade Pipeline Cascade Water Alliance Cascade Regional Water Supply System April 26, 2007 Fact Sheet Project Title Cascade Water Alliance, Cascade Regional Water Supply System, Tacoma-Cascade Pipeline Description of the Proponent The proponent of the Tacoma-Cascade Pipeline Project is Cascade Water Alliance (Cascade). Cascade was formed by a group of cities and special districts that own and operate public water systems in King County to jointly plan, develop, and operate a water supply system for its members. Each of these water systems is authorized to provide water within its designated service area. The members of Cascade have entered into an lnterlocal Agreement to enhance their ability to supply water to their respective service areas and the region by developing, owning, and operating regional water supply assets. The members of Cascade are: • City of Bellevue • City of Tukwila • City of Issaquah • Covington Water District • City of Kirkland • Skyway Water and Sewer District • City of Redmond • Sammamish Plateau Water and Sewer District Description of the Proposed Action The Proposed Action involves constructin and o erating a buried water su Tacoma-Cascade Pipeline ( ancillary features, to connec e existing Second Supply Pipeline (SSP) to the existing Bellevue-Issaquah Pipeline (BIP). The pipeline would be approximately 20 miles long and 42 inches in diameter and would bring water purchas€c! Ii Om I acoma Water to Cascade's members. Two action alternatives for the pipeline route (the Preferred Alternative and the Green Route Alternative) are being considered in addition to the No-Action Alternative. The action alternatives are located in King County within the following jurisdictions: • City of Bellevue • City of Newcastle • City of Covington • City of Renton • City of Issaquah • Unincorporated King County • City of Kent The majority of the pipeline would be constructed within public road rights-of-way. However, the pipeline would also cross private property and undeveloped lands. FINAL EIS: Tacoma-Coscode Pipeline Fact Sheet FS-1 Description of the Alternatives This Environmental Impact Statement (EIS) examines the following three alternatives: 1. No-Action Alternative. Under the No-Action Alternative, Cascade would not construct a new water transmission pipeline. Water would continue to be supplied through members' independent supplies, through wholesale water purchased by members from non-member water purveyors, and through a declining block contract with Seattle Public Utilities (SPU). Forecasted demands would not be met. Increased demand as a result of population growth, in combination with the declining SPU contract, would result in inadequate water supplies for Cascade members. 2. Preferred Alternative. The Preferred Alternative (see Figures 2-2 and 2-3) would be approximately 19.1 miles long. It would begin at the SSP, generally follow 160th Avenue SE or 164th Avenue SE north, and cross SR 18. There is also an option for the Preferred Alternative to continue on 164th Place SE, tum northwest on Covington Way SE, cross SR 18, and turn west on SE 272nd Street to 156th Place SE. It would then follow 156th Place SE, 156th Avenue SE, SE 224th Street, 148th Avenue SE, SE 192nd Street, and 140th Avenue SE to the SR 169 crossing. There is also an option in this area that would run cross- country on private property from near the intersection of 140th Way SE and SE 156th Street north to the SR 169 crossing. The Preferred Alternative would continue east on the paved Cedar River Trail. North of SR 169, the pipeline would travel north along 149th Avenue SE, Jones Road, and along 154th Place SE, then cross-country through a King County-owned parcel, along 156th Avenue SE, SE 144th Street, and 160th Avenue SE to SE 128th Street. The pipeline would then run east on SE 128th Street and then north on 176th Avenue SE to SR 900 in the May Valley area. From the May Valley area, the pipeline route would follow SR 900 northeast to the BIP. In south Issaquah, there are options along SR 900 to run cross-country, roughly parallel to a Puget Sound Energy (PSE) right-of-way. The jurisdictions along the Preferred Alternative include the cities of Covington, Renton, and Issaquah, and unincorporated King County. 3. Green Route Alternative. The Green Route Alternative (see Figures 2-2 and 2-3) would be approximately 21.9 miles long. It would begin at the SSP and continue north on 132nd Avenue SE. It would then turn east on SE 208th Street and north on 140th Avenue SE. The Green Route Alternative would follow the same route as the Preferred Alternative between SE 192nd Street and 156th Avenue SE. It would continue north on 156th Avenue SE, generally following SE 128th Street, 148th Avenue SE, SE May Valley Road, Coal Creek Parkway, and SE Newport Way to the BIP. The jurisdictions along the Green Route Alternative include the cities of Kent, Renton, Newcastle, and Bellevue, and unincorporated King County. Proposed/Tentative Implementation Date A decision will not be made about the Proposed Action until at least 7 days after issuance of the Final EIS. However, a proposed date for implementation would be the latter half of 2007. SEPA Lead Agency Cascade Water Alliance is the lead agency for this proposal. FS-2 FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet SEPA Responsible Official/Project Information Contact Person Michael A. Gagliardo, General Manager Cascade Water Alliance 11400 SE 8th Street, Suite 440 Bellevue, WA 98004 (425) 453-0930 ,k ( \,CADE Permits and Approvals that May Be Required for an Action Alternative Agency/Jurisdiction Federal U.S. Anny Corps of Engineers NOAA Fisheries/U.S. Fish and Wildltte Service Bonneville Power Administration State Washington State Depariment of Fish and Wildlife Washington State Depariment of Ecology Washington State Depariment of Health Washington State Depariment of Transportation Washington State Department of Archaeology and Historic Preservation Washington State Depariment of Natural Resources Local Jurisdictions King County FINAL EIS: Tacomo-Coscade Pipeline Fact Sheet Pennit/Approval' Section 404 Permit Endangered Species Act Compliance Land Use AgreemenVLetter of Notification 2 Hydraulic Project Approvals ' 401 Water Quality Certification Coastal Zone Consistency Determination NPDES Construction Stormwater Permtt Project Approval ' Temporary Variance to Noise Ordinance Franchise' Utility Permtts , Section 106 Review (Historic/Cultural Resources) Forest Practice Permrt ' Shoreline Substantial Development Permrt Clearing and Grading Permrt Right-of-Way Franchise for Utilities Short Form Clearing Permit -Geotech Right-of-Way Use Permit Special Use Permrt Haul Route Agreement 4 Building Permtt 2 FS-3 Agency/Jurisdiction City of Covington City of Issaquah City of Renton City of Newcastle City of Bellevue FS-4 Pennit/Approval 1 Grading Permit Right-of-Way Permit Haul Route Agreement• Building Permit ' Franchise Agreement Level 2 Administrative Site Development Permit ' Public Works Permit (Grading/Right-of-Way) Letter of Permission (Geotech) Haul Route Agreement • Building Permit Franchise Amendment Shoreline Substantial Development Permit Clearing and Grading Permit ' Right-of-Way Use Permit Haul Route Agreement 4 Franchise Agreement Special Use Permit -Cedar River Trail 5 Clearing and Grading Permit Right-of-Way Use Permit Haul Route Agreement• Building Permit Franchise Agreement Clearing and Grading Permit Right-of-Way Use Permit Haul Route Agreement• Building Permit : Franchise Agreement i FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet Agency/Jurisdiction Pennit/Approval 1 other BNSF Railway Pipeline License Puget Sound Energy Land Use Agreement '·' Ta coma Water Crossing Permit Seattle Public Utilities Utility Crossing Penni! ' Temporary Use Penntt (Lake Youngs Trail) 2 Notes: 1 -This table lists the key permits/approvals known at the CtJrrent time. Ongoing agency consu~tion may detennine that additional approvals would be required. 2 -May not be needed; need would be determined during ongoing consultation. 3 -Because of the linear nature of the proposed project, more than one permtt may be required. 4 -Would be obtained by the contractor. 5 -The City of Renton advises that approvals may be required from the lnteragency Committee on Outdoor Recreation and from the Washington State Department of Transportation. This would be confirmed in ongoing agency consultation. Principal Contributors to the EIS The individuals listed below were principal contributors to the preparation of the EIS. For more detailed information about the education and experience of the principal contributors, see Appendix C. HOR Engineering, Inc. Mike Stimac, PE Marc Auten Megan Bockenkamp Ron Grina, AICP Karissa Kawamoto, AICP Fusan Lin, PE, PTOE Bonnie Lindner Joshua Shippy, PE Pat Togher, PWS Barb Whiton GeoEnglneers. Inc. Gordon M. Denby, PE, PhD Jodie Lamb, LG, LEG EIS Manager Environmental Scientist Environmental Scientist Environmental Planner Environmental Planner Transportation Engineer Regulatory/Permitting Lead Transportation Engineer Wetlands Scientist Technical Editor Senior Principal Project Geologist Historical Research Associates, Inc. Denise DeJoseph FINAL EIS: Tacoma-Cascade Plpeline Fact Sheet Project Archaeologist FS-5 Draft EIS The Draft EIS was issued on December 21, 2006. The comment period for the Draft EIS ended on February 2, 2007. Cascade received written comments on the Draft EIS from federal, state, and local agencies; from the tribes; from non-governmental organizations; and from private citizens. The comments received on the Draft EIS are addressed in this Final EIS. Final EIS Date of Issuance April26,2007 Locations to Obtain Copies of the Final EIS The Final EIS is available to the public online at www.cascadewater.org. The Final EIS is also available on compact disc for a cost of $2, or hard copy for $40, from the following address: Cascade Water Alliance 11400 SE 8th Street, Suite 440 Bellevue, WA 98004 (425) 453-0930 Copies of the Final EIS are available for review at the following libraries: • King County Library System 0 Fairwood Branch 0 Maple Valley Branch 0 Covington Branch 0 Kent Regional Branch 0 Issaquah Branch 0 Newport Way Branch 0 Bellevue Regional library • Renton Public Library • University of Washington Suzzallo Library Subsequent Environmental Review The following studies may be performed and plans developed once an alternative is selected: • Erosion and Sedimentation Control (ESC) Plan • Wetland Mitigation/Restoration Plan • Biological Assessment (to meet Endangered Species Act requirements) FS-6 FINAL EIS: Tacoma-Cascade Pipeline Fact Sheet • Critical Areas Study • Stormwater Pollution Prevention Plan (SWPPP) • Spill Prevention Control and Countermeasures (SPCC) Plan • Traffic Control Plan • Phase I Environmental Site Assessment • Phase II Environmental Site Assessment • Compliance with Section 106 of the National Historic Preservation Act Background Documents Technical reports, background data, adopted documents, and materials incorporated by reference for this EIS are available for public review at the following address: Cascade Water Alliance 11400 SE 8th Street. Suite 440 Bellevue, WA 98004 FINAL EJS: Tacomo-Coscode Pipeline Fact Sheet FS-7 , , i ,.. .. ) -· .,.. Preferred Alternative Graen Route Alt8ma1ive = Bel~vue-lssaql<llh Pipeline = SPVTransmlssionUne = TWTrarr.amisslon Une C3 Prop05ed Location of Rechlorlnatkm Faculty ~ Municipal Boundary "''· Stream/River Highway Seoondary Road 2,000 4,000 6,000 .. ' t • '" ··-,.; .. , I • ' . ~ I Up \.,_J Cougar Mountain Squak Mountain Cedar Hills Landfill ' \ I ( L_J i --- I \ RGURE2-2 Tacoma-Cascade Pipeline (TCP) Preferred and Green Route Alternatives Green NtemalM! Blue Allernative Light Blu" Option Black Ahim18tlv8 North Segment A.hamatlves • Lower Reach -Blue Alternative Red Option RoseAltemolive North S.gment Altem.ttv--Upp« Reach -Plum Alternative PlumOptiol'I Orar,geAl!emptiva Orange Option Lime Altam01ive Lime Option = Bellavua-lssaquah Pipeline = SPVTr110sml!ililOOLine = TWTransmlssion Une ~ Municipal Boundary Stream/River Secondary Road ·~ ""'-10'_ .. ~ ... _._ .... l-iJt, I ' ' ~- j J-, __ ./ .. ·----. ' "-------~ ' '\ / ( ( \ •' il .(."-: I r y -, ' Squak Mountain Cedar HIHs Landfill L •• J RGVRE2-1 Tacoma-Cascade Pipeline (TCP) Route Alternatives Described In the Route Study Reports Pre fM'8d Alttt-native Green Route AUernaive C3: Prop00ed LocalKln of Rechlc..-inaOOn Facili ty Tacoma-Cascade Pipeline (TCP) Preferred and Gr een Route Alternatives (Ae rial Photo) Legend Prererred AlternOOva Greon Rol..te Alternativ e N W+E s RGURE 2-3 (S,_t 1 of 2' Tacoma-Cascade Pipeline (TCP) Preferred and Green Route Alternatives (Aerial Photo) >>From: "Johnson, Ken" <Ken.Johnson@METROKC.GOV> •>> To: 'Highlands Neighbors' <highlands_neighbors@hotmail.com> >>CC: "Crawford, Curt" <Cu1t.Crawford@METROKC.GOV>, "Isaacson. Mark" >>dvlark.lsaacson@METROKC.GOV> >>Subject: RE: Thanks for your call! >>Date: Tue, 7 Feb 2006 16:43:32 -0800 >> >>Ms High, >> >>Sorry for the delay. As I said before, I do not have the expertise in the specifics of many of the issues you raised, so have had to consult others here in Water and Land Resources Division. I myself haven't been to directly view the recent slide, but understand that it has gotten some attention from some of the drainage engineers. as is reflected in sorrieof--- ~sponses. The fol lowing arc your questions copied in: >> >>l) To what degree did the 4 most recently cleared subdivision sites Evcndell, Liberty Grove, Liberty Grove Contiguous and Nichols Place) contribute to this event? >> >>A: Evendell, Liberty Grove, Liberty Grove Contiguous and Nichol's Place all front on 160th Ave SE at or near the intersection with SE 136th St. All four of these rojccts have detention systems and do not mfdtrate their runoff (they .-arc located on relatively impervious soil layers). The outfall from l ese ro eels appears lo ow south then southeast and eventually west 111 conveyance on SE 144th St with eventual discharge into the creek next to l. t 1 Pl SE. It is unlikely an of these ro·ects contributed si nificimt recharge to groundwater and to the landslide that occurred near SE 148th St and 158th Ave SE. In addition. the clearing of an area has a muc greater effect on runoff than on recharge, and can actually reduce recharge because of the increase of impervious pavement and removal of shallow perched zones of groundwater, especially at the locations of these developments because or the nature of the subsurface in this location. Sec the response to question 11 for additional infom1ation. >> >>Also, you should note that some of the older houses in the area are (or were at one time) on septic systems --such drain fields contribute water to the shallow groundwater system. This is not the case for the newer construction such as the 4 subdivisions, which are on sanitary sewers. >>---------------------------------------------------------------------------- >>~) What can be done to minimize future comparable events? >> >>A: The landslide at SE 148th St and 158th Ave SE was groundwater driven, in that there was no surface runoff until the groundwater expressed itself on the slope. We believe that this event was mostly a natural occurrence --similar landslides probably ocnmed throughout history since the Cedar River cut its valley and left this slope. It is hard to work against natural phenomena, and such landsliding is mainly a problem for the property owner on top or beneath the landslides. King County, like other jurisdictions, tries to limit development in areas like this, through its >>landslide hazard critical area regulations. >> >>Our records indicate that there is some possible, but minor, human element in initiation of this slide. A reconnaissance of this drainage in 2003 documented trash and "yard debris and other junk" in the area that failed. >>This trash may have contributed to the failure by restricting groundwater discharge, loading the slope. and by preventing establishment and growth of vegetation. So, general maintenance/ cleanup of drainage channels and >>vegetation establishment could help f()['estall a landslide temporarily, but would have little effect against the deeper, overwhelming, natural driving forces Lhat really cause these landslides. >> >>If property owners arc concerned about landslides regarding a slope on thcil' own property they should consult a Geolechnical Engineer for recommendations. \Vealhering. sloughing, and even collapse of slopes is an ongoing natural process. Without site-specific information, it is unknown where the groundwater will express itself and thus initiate slope instabilities. Given such uncc1tainties, and the great expense to study and rcmediatc a slope stability problem, it is probably better for some property owners to wait until there is a better indication that protection of the >>slope would in fact be necessary. >>---------------------------------------------------------------------------- > >-· ---------------· --· - ·>>3) This slide occu!Ted in a Category 2 Critical Aquifer Recharge Zone. By what methodology and based on what datasets was the boundary of the Aquifer zone set'' >> >>A: The Critical Aquifer Recharge Arca was mapped using regional-scale maps of surficial geology and soi Is, estimates of depth to water, and protective designations such as \Vellhead Protection Areas and/or Sole Source >>Aquifers. The specific vicinity of the slide was mapped to be a Category 2 mainly because the surface soils arc glacial outwash materials (Vashon Recessional Outwash or Qvr) that readily infiltrate water. With any regional scale >>mapping or interpretation, there are going to be errors about where exactly the boundaries from one zone to another should be drawn. There are methods for revising these mappings, and they are being revised on a long-term basis. >> >>You should note that at the hillside in question, the regional geologic map shows a dense geologic unit (Vashon Till or Qvt) underlying the Qvr which prevents much of the water from flowing to deeper zones. so this could be >>allowing ( or forcing) the groundwater to flow out to the slope in this area. and thus make the slope more susceptible to landsliding. Some of our personnel. who examined the slope soon after the landslide. report that the Qvt is not present at the immediate location. However, they did report that the landslide slope docs show a Qpf layer that is also a low penneability geologic unit (generally lying deeper than the Qvt) and which similarly limits the deeper infiltration of groundwater. >> >> You should also note that fu1ther north, away from the slope, the Qvt is mapped to be at the surface, including in the area of the four developments you discussed in Question I. In this case these parcels probably contribute little recharge directly on their sites. If Qvt is at the surface, then there is no Qvr at the locations of the developments, so there may not be a near-surface aquifer way to communicate groundwater from these locations to the landslide area. >> >>We don't have the regional scale geologic map available on our web site, but you can sec the best present King County geologic map via the UW area: >>http:// gcomapn w .css. w ashi ngton.cdu/indcx. php'/toc=mai nt.oc&bod y=servi ces/maps. htm >><http://geomapnw .ess. was hi ngton .cdu/i ndcx. php?toc=mai ntoc&bod y=scrvices/maps htm> >>(The map is very large so you should have a high-speed connection to view it.) >>---------------------------------------------------------------------------- >>4) Has this event "pulled the plug" on the aquifer recharge zone? >> >>A: No, we do not think that this event has "pulled the plug" on the aquifer (this applies to the entire aquifer rather than just the recharge zone) --i.e .. we don't think that subsequent recharge will just flow out immediately without building up (such as happened at the High Rock site near Monroe). >>As mentioned in the previous response. there is a layer of Qvt or Qpf that impedes deeper infiltration. When recharge reaches this nearly impervious layer the water above it moves horizontally, and usually flows out at >>lower elevations as springs along the hillside. The small amount of material that was lost due to this slide has not substantially reduced the storage capacity of the aquifer, nor has it opened up a major channel [or discharge. >>Because the slide probably has not pulled the plug on the aquifer, a similar series of rainfall events will likely produce a similar result of infiltrated water seeking an expression on the Cedar River Valley slope as it did this time, and perhaps initiate further landsliding. >>---------------------------------------------------------------------------- x>>5) Is the aquifer recharge zone now at higher risk for settling and subsidencc 9 Should propeny owners be aware ol" such a risk'' What can they do to prepare for such occurrence? >> >>A: Subsidence should not be a problem on the top of the plateau as long as piping" docs not occur within the landslide scarp area. (Piping is the erosion out of soil materials by continued water flow from a hillside --it occurred in the big landslide that temporarily dammed the Cedar River a couple thousand feet west of this slide, after the Ni squally Earthquake in 2001 and local landowners had gravel "shot" into the widening hole to slop the piping.) Our field personnel report that there had been evidence of piping that occurred immediately after the landslide, but these "pipes" >>were dry soon afterwards and no more erosion was taking place (the little bit of seepage that continued was ocrnrring further down the slope). >> >>Note that subsidence is not an issue regarding the recharge zone further back from the cliff, but only a local ,condition above the slide area. A greater threat is the soil movement that can be a direct effect or landsliding, with the properties at the top or the slope starting to move along with the soi I as it begins to fail ( even if the houses do not rail >>clown the hill). Property owners along and close to the bluff edge should be aware of the possibility of landsliding at some time in the future, and contract a geolechnical study of their· property if they want to get some >>kind of reassurance. Again, this does not apply to the bulk of the aquifer recharge area, away from the bluff. >>---------------------------------------------------------------------------- >>6) Will the aquifer recharge zone be able to store future rainfall, or will the water continue to shoot out the side of the hill? >> >>A: The aquifer appears still able to store future rainfall. It is likely the short time and high rainfall amount was the cause of an overflow of the localized storage available underground. This is similar to having a bowl overflow when too much liquid is pomed into it. When the groundwater has achance lo spread out it will reach the appropr'iate elevation for the flowfrom the slope to reduce or slop. But like a bowl, if you put too much water in it, it will overflow. (This question appears to be the same as Question #4.) >>---------------------------------------------------------------------------- >>7) Under ideal circumstances. what can property owners in the aquifer recharge zone do to minimize future similar events? What development standards and practices could be set in place lo minimize 1·utL1re comparable events? >> >>A: This landslide (like many others in the area, throughout history) appears to be a natural event d1ivcn by rainfall, soil type, soil geology, and erosion, rather than a mistake by any one individual or group. It is a complex interaction and a concemccl property owner may want to contact a Gcotechnical Engineer for a more complete evaluation of their own propct1 y. >> >>Without knowing all the causes and interactions a conclusion for the best development standards and practices cannot be determined. >>---------------------------------------------------------------------------- >>8) What arc the exact locations of all the slides currently being monitored (or resulting from the same events as the largest slide)'/ >> >>A: We arc aware of the following landslides in the vicinity and have investigated them but no monitoring plan is in place at this time. >> i. 14911 SE 145th Pl >> ii. 14217 SE 146th St >> iii. 13715 139th Ave SE >>---------------------------------------------------------------------------- >>9) How may we correctly request maps of the drainage features upstream or each of these slide locations') >> >>A: For flow control and water quality facilities outside a highway Right-of-Way contact Dave Hancock at 206-296- 8230. For drainage features inside a King County Right-of-Way contact the Depar1ment of Transportation at 206-296- 8100. >>---------------------------------------------------------------------------- >>10) What is the communication model by which the lessons learned from theseevents arc communicated to DOES so tl1at foture subdivision applications are reviewed with appropriate consideration of the circumstances that led lo >>these events so that future negative events can be minimized'! >> >>A: As in the answer to Question #7 (and other responses). we believe thatthis recent event was substantially natural. We already have regulations to avoid infiltration too close to the edge of a potentially unstable slope. >>In general. across the extent of King County. we want to encourage recharge infiltrntion, to preserve the groundwater resources that sustain stream flows and fish habitat. However, we already try to avoid al lowing infiltration too close to unstable slopes. >>---------------------------------------------------------------------------- >>11) Some precipitation is captured by re/detention ponds, some !lows off asxsurfacc runoff and some soaks into the ,ground and becomes ground water, recharging aquifers. Clearing of vegetation accelerates the speed at which >>precipitation and some surface water soak into the ground bccausetrees/vegetation slow this process and also capture some pf the water fortheir own use. I don't know how rapidly this occurs, but certainly thcrewas a direct connection between massive volumes of rain and the hugeincreascs in the groundwater that apparently precipitated the slide. I >>can't see the flaw in the logic that clear cutting acres and acres of groundxmay well have contributed to increased volumes of groundwater in theaquifers and that this happened much more rapidly than it did when thetrccs/vcgctation were there. It seems to me that rain slowly seeping intothc earth would spread the increase in the volume of groundwater over agreater amount of time and reduce the probability of a slide. >> >>A. In general, development of a site causes less water to infiltrate andmore water to leave the site as surface runoff. Observation of these four projects is consistent with this generality because surface water was seen leaving the site from the flow control facilities long after the actual rainfall has ceased. The surface water that leaves these sites is >>conveyed as surface water to the stream along 154 Pl SE. While a small amount of this water may infiltrme in the roadside ditches, the vast majority of surface runoff was safely conveyed away from any area where it could have >>contributed to this landslide, perhaps even all the way down to the Cedar River. >> >>lt is correct that removing vegetation can affect the hydrology of a site. Usually. a vegetation-covered site will infiltrate a much larger percentage of rainfall than a cleared site. However, the top layer of soil under the >>vegetation, especially in forested areas, is much more impottant from a hydrologic standpoint. The variable ground surface, vegetation and ground Jitter slows the movement of runoff across the land giving it more time to >>infiltrate. >> >>The near-surface soil in the area of these developments is derived from till Qvt) a soil type called Aldcrwood soils, and very different from the soil Qvr, or Everet\ soils) that is present near where the landslide occurred. >>Alderwood soil bas a very slow infiltration rate and tends to resist additional moisture. These four development sites capture nearly all runoff in the drainage catch basins and detention system. It is not immediately apparent that water infiltrating at these sites would even reach the landslide area. >> >>In short, because this landslide was a groundwater related incident it is unlikely that the mentioned developments had any influence on the cause of the landslide. >>---------------------------------------------------------------------------- >>Please feel free to share this e-mail with your members or anyone else. Also, feel free to contact me if you have further questions. >> >> Yours, >>--Ken >> >>Ken Johnson >>Water & Land Resources Division >>Dept. of Natural Resources & Parks >>201 S. Jackson St., Suite 600 >>Seattle, WA 98104-3855 >>Internal mailstop (MS): KSC-NR-0600 >>Web: http://dnr.metrokc.gov/w lr/wq/ groundwater.htm >><http://dnr.mctrokc.gov/wlr/wq/groundwatcr.htm> >>Phone: (:~06) 296-8323 >>Fax: (206) 296-0192 >> >> >> . ·, ;- RE: Evendell L03RE038 and Nichols Place L03P0015 From. Highlands Neighbors (highlands_neighbors@hotmail.com) Sent: Wed 8/09/06 9: 19 AM To: Paula.Adams@METROKC.GOV Excelle:-it. ~hank you. g C.A.R.E. -C~tizens 1 Alliance for a Responsible Ever1dell ... doing ·._.1haL we can, with our ::1.eighbors, for our co::ununity ... "l'Jv..l\v.highlandsneighbors.org >From: 11 Adams, Paula" <Paula.Adarns@METROKC.GOV> >To: "Highlands Neighbors 11 <highlands_neighbors@hotmail.com> >Subject, RE, Evendell L03RE038 and Nichols Place L03P0015 >Date, Wed, 9 Aug 2006 09,17,40 -0700 > >I am legally obligated to document in writing that I am responding and when you will be able to review the records. > >-----Original Message----- >Frorn: Highlands Neighbors [mailto:highlands_neighbors@hotmail.com] >Sent, Wednesday, August 09, 2006 8:23 Al1 >To: Adams, Paula >Subject: RE: Evendell L03RE038 and Nichols Place L03P0015 > >CARE >PO Box 2936 >Renton WA 98059 > >But. Why? > >I am concerned about the potential unanticipated consequences. Specifically, I do not intend to incur any unintended costs. > >I'm sure that we discussed that you would merely gather the resources and then, upon your notification, our folks would come down to the ODES offices and review the files there. At that time we will choose which documents to copy -and thus the level of time and expense we are willing to expend in this effort. I expressly DO NOT request or authorize any activity that will obligate CARE to any financial responsibility otherwise. > >Thanks, >g > >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what >we can, with our neighbors, for our community ... >wv.rw.highlandsneighbors.org > > > > >From: "Adams, Paula" <Paula.Adams@METROKC.GOV> > >To: "Highlands Neighbors" <highlands_neighbors@hotmail.com> > >Subject: RE, Evendell L03RE038 and Nichols Place L03P0015 > >Date, Wed, 9 Aug 2006 07:50,02 -0700 > > > >Ok. > > I'll start working on it. > >-----Original Message----- I need a mailing address for you right away. > >From: Highlands Neighbors [mailto:highlands_neighbors@hotmail.com] > >Sent, Tuesday, August 08, 2006 3:10 PM > >To: Adams, Paula > >Cc: Warden, Stephanie; Miles, Joe; Pray, Jeff; Dunn, Reagan; Chealum, > >Tim; 'I'ownsend, Steve; Hammond, Terry; Scharer, Bi 11; Moore, Bernard; > >Dykeman, Mike; Ombudsman; Sanders, Jim; Gallagher, Wendy; Spohr, David > >Subject, RE: Evendell L03RE038 and Nichols Place L03P0015 > >Eel"l.o Ms. Adams, > > > >1/i.1hen we spoke th is morning I was p:::-el Ly muc:h convir:ced Lo give in to yo-c. suggcs tion of wu.iti.ng to see if all our iss:..1es co·~tld be rcsolvP-d at the mee:=ing srhedu.::...ed for 'T'}:ursday evening. However, please understand chat I am fuLCL_:_o.ning 1a;gcly as a fuc:i_ l 1-tator betwee:1 your Ocpartment a:1d my com."Tlunity. Thus, upo;1 cor:sultation with the residenls who have ~;c.:Efe:::·ed lhe impacts of constructiol1 at the Evendell and Nichols Place projects, and :'._n light of your impending departure, we re-.ilerate ouY n?qu.est (A'-.1.gust 1, 2006) for documer_tatio:-i: > > > >Drainage: > >We request copies of all corrective measure directives fo:r:-drainage retcrcnced in the 9DES response transmitted by Stephanie Warden on July 27, 2006 via email to us, along witl1 ~11 relevant correspondence. > > > >Setback violatior1s: > >We request copies of all corrective measure directives for setback violations referenced in the DDES response transmitted by Stephanie Warden on lJuly 27, 2006 via email to us, along with all relevant correspondence. > > > >Additionally, last week Ms. Thorbeck wrote to DDES personnel, Bill Shaerer, Bernard Moore and Terry Hammond, that the units on lots 19 and 20 have been sold and asked them to provide explanation of the apparent inconsistency between your response below and the fact that units have been sold. Ms. Thorbeck has still received neither acknowledgement of this corrununication nor any answer to her inquiry. It seems highly unlikely that a residential lender would approve financing for a dwelling currently not eligible to receive an occupancy certificate. We formally request substantive explanation of the discrepancy as well as for why Ms. Thorbeck continues to be 100% ignored. > > > >Code Violation Complaint: > >We request all relevant documentation associated with this code enforcement complaint. > > > >Unprofessional and unresponsive staff behavior: > >The Telephone Protocols have been provided. Thank you. However, as we stated previously: We fail to comprehend your reasoning. When citizens submit complaints, and despite repeated follow-up contacts vie email and telephone, never receive acknowledgement of receipt, much less a status update, by what standard can this conduct be deemed professional or timely? > > > >Also, we now request these documents: >>-all building footprint/layout proposals that have been submitted >>-all documentation related to drainage, flooding or the movement of any and all non-sewage water for both sites >>-all documentation related to grading and bulk earth movement on both sites >>-all HOA related documentation >>-all documentation related to the homeowner restrictions for drainage, fencing and landscaping > > > >We understand that you have a staff/resource challenge. Therefore, we agree to you suggestion that the comprehensive raw file set {bankers' boxes, etc.) should be sufficient for our purposes and waive any expectation for DDES staff to 'sift and sort'. We will send residents to review and choose which documents to copy as soon as you tell us where and when. > > > >Further, we understand that it is not likely that the documentation will not be made available for our review before the meeting of Thursday, August. We do request thaL the gathering effort begin now, so that additional delay may be minimized and documents can be reviewed as soon as possible. If it will facilitate your operations, we may even be able to review these materials in batches as they are made available to you by individual staff members. > >Please let us know as soon as possible what arrangements we might expect. > > > >Thank you for you efforts in this matter, Gwendolyn High -president > > > >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what > >we can, with our neighbors, for our community ... > >~.highlandsneighbors.org > > > > >From: "Highlar:ds Neighbors" <h 1 ghla7lds_r:.eighbors@hotrnu '. l . cof'."l> > > >To: Stephanie. v','arden@K.2;':::"'ROKC. GOV > > >CC: Joe. MJ 1 es~4ME'I'ROKC. GOV, Jeff. Pray@MET20KC. GO',],> > >ReagaL, Du:in(d)1ETROKC. CCV, Tir.t. C~'l.eatum@METROKC. GOV,> > >Steve. Townsend@::vtETROKC. COV, Terry. Hu.mrno::id(4:!'1ET.ROKC. GCV, > > >Bill. Scha rer@METROKC. GOV, Bernard. Moore@MF'.TROKC. GOV,> > >Mi.~e. Dykcman@METROKC. GOV, ?aula. AdamsC.JMETROKC. GOV,> > >Ombudsrnu:1@MET?DKC. GOV, Jim. Sanders(9-M:R'T20KC. GOV,> > >T/llendy. Gallaghe:r@M2TROKC. GOV, 1::av:i (j. ;]·;:>oh rCdT:,fr;T:·;:c.:.:::.c. cov >>>Subject: RE: .Evendell LC3XE038 anci Kicho=..s Place L03P0015 > > >Date: Tue, 01 Aug 2006 c0:30:19 -0'/00 > > > >>>Good Morning, Ms. Warden, > > > >>>Our initial response is attached. We look forward to reviewing the requested materials as soon as possible. > > > >>>Thank you, >>>Gwendolyn High >>>president > > > > > >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing > > >what we can, with our neighbors, for our conununi ty ... > > >www.highlandsneighbors.org > > > >>>>From: "Warden, Stephanie" <Stephanie.Warden@METROKC.GOV> >>>>To: "Highlands Neighbors" <highlands_neighbors@hotmail.com> > > >>CC: "Miles, Joel! <Joe.Miles@METROKC .GOV>, "Pray, Jeff 11 > > >><Jeff.Pray@METROKC.GOV>, !!Dunn, Reagan" > > >><Reagan.Dunn@METROKC.GOV>,"Cheatum, >>>>Tim" <Tim.Cheatum@METROKC.GOV>,"Townsend, Steve" > > >><Steve.Townsend@METROKC.GOV>,"Hanunond, Terry 11 > > >><Terry.Hamrnond@METROKC.GOV>,"Scharer, Billn > > >><Bill.Scharer@METROKC.GOV>,11 Moore, Bernard" > > <Bernard• Moore@METROKC. GOV>, T( Dykeman I Mike 11 > > >><Mike• Dykeman@METROKC. GOV>, 11 Adams, Paula !I > > >><Paula.Adams@METROKC.GOV>, "Ombudsman">> >><Ornbudsman@METROKC.GOV>,"Sanders, Jim!! > ><Jim.Sanders@METROKC.GOV>,"Gallagher, Wendy">> >><Wendy.Gallagher@METROKC.GOV>,"Spohr, David">> >><David.Spohr@METROKC.GOV>,"Spohr, David" <David.Spohr@METROKC.GOV> >>>>Subject: Evendell L03RE038 and Nichols Place L03P0015 >>>>Date: Thu, 27 Jul 2006 13:05:53 -0700 > > >> >>>>Dear Ms. High: > > > >>>>Thank you for your e-mails expressing the interest and concerns you and the Citizens' Alliance for a Responsible Evendell, or C.A.R.E., have with the Evendell, L03RE038, and Nichols Place, L03P0015, developments. >>>>I understand your concerns fall into the following categories; > > > > > > > > > > > > > > > > > > > > > > >> >>* >>* >>* >>* >>* >>* >>* >> >>Drainage: >> Drainage Adjacent structural damage Setback violations Encroachments Unfulfilled Hearing Examiner required mitigation Code violation complaint Unprofessional and unresponsive staff behavior >>>>During the winter of 2005-2006, Land Use Inspector Tim Cheatum, of the Department of Development and Environmental Services (DDES), addressed the matter of controlling surface runoff with the Evendell developer/builder. They discussed using cutoff swales to direct surface runoff toward the road collection system. The required stub-outs at the catch basins were installed during plat construction. > > >>>>Land Use Inspection staff coordinated with the Building Inspection Section (BIS) staff, to assure the plat drainage design conformed to the building codes. BIS Inspector Terry Hammond issued a correction notice directing the builder to bring the lot drainage issues into compliance with plat engineering plans. No further occupancy approvals for these homes will be granted to the builder until the drainage issues are properly addressed. / > >-> > > >>Silt-fe~cing and othc~ standa~d contra] methods throughol1t the site arc u~der ti1e cu:1trol of Lhe H::::S inspeclo.r who issued bot:.:"l verba.::.. an("i vvriL.len co::::-rection not i cc:.; to ':-'.ne :Ou~ .Lder. ','·Je [1ave not idcntifle6 any 2.dverse impacts to Lhe sensitive a:::::·eas resul t.iEi;:J fro.c:1 :his n:noff. > > >> > > >>F~dj acent s::~uctural damage: > > >> > > >>You reference construction activity causing broken windov.1s and damages lo a hoi...:.se. Claims for dD.mages are a civil matter between property mvners. lf you :lave a claim tor damages invol vir.g cons Lruction activity, please submit it directly to the devc1oper/bui lder Sound Bu.::..l t Ho;-r_es fo:::::-resolution. > > >> >>>>Please submit any claim for destruction of adjacent landscaping or trees caused by earth- moving equipment to the developer/builder. > > >> >>>>Setback violations: > > >> >>>>You reference a foundation four feet from an adjacent property line, but do not gi.ve its location. After reviewing the attachments sent with an e-mail dated June 28, 2006, we assume the lot line is in the Evendell Plat, between lot 19 and the Thorbeck property. We are also assuming this is where interior setbacks (between lots 19 and 20) appear to be less than 10 feet. Terry Hammond has issued a correction notice requiring the builder to re-establish the property corners through a survey. DDES will take action if the survey determines the setbacks are inadequate, and occupancy will not be granted until the matter is resolved. > > >> > > >> Encroachments: > > >> >>>>The encroachment issue became apparent during the early construction of the detention vault. The developer/builder did not have permission, or a construction easement from the adjacent property owner to proceed. Obtaining permission is the responsibly of the developer. When the developer did not produce documented permission, the work was stopped by DDES. A plan change was required causing the builder to use construction techniques that did not require excavation past the property line. > > >> >>>>Unfulfilled Hearing Examiner required mitigation: Your letter suggests the Hearing Examiner's conditions regarding street trees were not satisfied. > > >> >>>>Installation of street trees is not requited by code for two years after recording. The developer has posted a financial guarantee to assure the work will be performed. (See the attached e-mail from Jeff Pray.) > > >> >>>>Code Violation Complaint: Your letter references a complaint. > > >> >>>>We are unable to determine which complaint #390" (filed May 23, 2006) is unfamiliar to us. this matter, we will address it. > > >> you are referencing, as the phrase, "Ref. If you have additional information to clarify >>>>Unprofessional and unresponsive staff behavior: Your letter indicates our staff has been unprofessional and unresponsive. > > >> >>>>After interviewing DDES staff, I have determined that our responses were handled in a timely and professional manner. We will continue to monitor this project for compliance with all code requirements. As stated above, civil matters are not within DDES' authority to >resolve. > > >> >>>>The subdivision project files are available for public review. If you wish to schedule an appointment to review these materials, please contact the DDES Records Center at 206-296- 6696. Please contact Building Inspection staff at 206-296-6630 for access to the building files. > > >> >>>>If you have additional questions, please contact Bernard Moore, Building Inspections Supervisor, via e-mail at Bernard.Moore@metrokc.gov <mailto:Bernard.Moore@metrokc.gov> , or by > >telephone at 206-296-6762. > > >> >>>>Thanks you again for taking the time to e-mail. > > >> >>>>Sincerely, > > >> > > >>S:.cphanie T,1,rarden >>>>Director Dcpaitment o~ ~evelop~ent and Environmental Services > > >> > > >>-----Origical Message----- >> >>From: Highlands Neighbors [mailto:highlands_neighbors@hotrnail.com~ >>>>Sent: Thursday, Culy 27, 2006 6:22 AM > > >>To: r,,.rarden, Stephar:ie > > >>Cc: highlands_neighbors@hor.mail.com; Miles, Joe; Pray, Je£:f; Dcnc,> > >>Reagan; C:heal:..12'1, Tim; Townsend, Steve; Hammond, Terry; Scharer,>> >>Bill; Moore, Bcrr:ard; Dykeman, Mike; Adar:1s, Paula; Ombudsman;> > >>Ortiz-Olguin, Cathy; Sanders, Jim; Gallagher, \',.1endy; Spo~1r, David > > >>SUbJect: RE: COMPLAINT: Evendell L03RE038 and Nichols Place L03P0015 > > >> >>>>Good Morning, Ms. Warden, > > >> >>>>Can you direct us to the correct person and/or method for contact and answer to the simple question below? I am sorry to bother you, but yet another week has passed and we continue to be 100% ignored. > > >> >>>>Your assistance is greatly appreciated. > > >>Thank you, >>>>Gwendolyn High > > >> > > >>C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what we can, with our neighbors, for our community ... > > >>\.\TWW,highlandsneighbors.org > > >> >>>>>From: "Highlands Neighbors" <highlands_neighbors@hotrnail.com> >>>>>To: highlands_neighbors@hotmail.com, Joe.Miles@METROKC.GOV, > > >> >Jeff.Pray@METROKC.GOV >>>>>CC: Reagan.Dunn@METROKC.GOV, Tim.Cheatum@METROKC.GOV,> > >> >Steve.Townsend@METROKC.GOV, Terry.Hammond@METROKC.GOV,> > >> >Bill.Scharer@METROKC.GOV, Bernard.Moore@METROKC.GOV,> > >> >Mike.Dykeman@METROKC.GOV, Stephanie.Warden@METROKC.GOV, > > >> >Paula.Adams@METROKC.GOV, Ombudsman@METROKC.GOV,> > >> >Cathy.Ortiz-Olguin@METROKC.GOV, Jirn.Sanders@METROKC.GOV,> > >> >Wendy.Gallagher@METROKC.GOV, David.Spohr@METROKC.GOV >>>>>Subject: RE: COMPLAINT: Evendell L03RE038 and Nichols Place > > >> >L03P0015 >>>>>Date: Thu, 20 Jul 2006 08:34:26 -0700 > > >> > >>>>>Good Morning, Mr. Pray, > > >> > >>>>>It has been a month since the submission of our official complaint with no substantive response. It has been one week since I sent the inquiry below. Since we have not received any word from you on the simple question below, I thought it time to reiterate. > > >> > >>>>>"We look forward to the written response to our official complaint. It should be helpful to all in preparation for the August 10th meeting. When shall we expect it?" > > >> > >>>>>Your response would be most appreciated. If I am not addressing this question to the appropriate person, please direct me to the responsible party as soon as possible. > > >> > >>>>>Thank you, >>>>>Gwendolyn High > > >> > > > >> >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing >>>>>what we can, with our neighbors, for our corrununity ... > > >> >www.highlandsneighbors.org > > >> > >>>>>>From: 11 Highlands Neighbors" <highlands_neighbors@hotrnail.com> >>>>>>To: Joe.Miles@METROKC.GOV, Jeff.Pray@METROKC.GOV > > >> >>CC: Reagan. Dunn@METROKC. GOV, 1'im. Cheatum@ME'I'ROKC. GOV,> > >> >>Steve.Townsend@METROKC.GOV, Terry.Hammond@METROKC.GOV,> > >> >>Bill.Scharer@METROKC.GOV, Bernard.Moore@METROKC.GOV,> > >> >>Mike.Dykeman@METROKC.GOV, Stcphanie.Warden@METROKC.GOV, > > >> >>Paula.Adams@METROKC.GOV, Ombudsman@METROKC.GOV,> >>>>>Cathy.Ortiz- Olguin@METROI<C.GOV, Jirn.Sanders@METROI<C.GOV,> > >> >>Wcndy.Gallagher@METROKC.GOV, Dov _:_a. Spoh:.c-@ME'":"'ROKC. GOV > > > > > > > > > > > > >> » » » >> >> >>SubJ'ect: R.::.:: COM?I,1\INT: Evendel.:_ L03RE038 and Nicho.ls Place >>L03P0015 >>Date: Thu, 13 Jul 2006 15:04:21 -0700 » >>Dear Mr. Miles, » > > >> >>Thar.k yoi_; for the update. > > >> >> > > >> >>1·'ie look forward to the written response to our official complaint. > > >> >>IL should be helpful to all ir1 preparation for the August 10-:::h meeting. >>>>>>When shall we expect it? > > >> >> >>>>>>Thank you, >>>>>>Gwendolyn High > > >> >> > > >> >>C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what we can, with our neighbors, for our community ... > > >> >>V'/\vW.highlandsneighbors.org > > >> >> > > >> >>>From: "Miles, Joe" <Joe .Miles@METROKC .GOV> >>>>>>>To: ''Highlands Neighbors'' > > >> >>><highlands~neighbors@hotmail.com>,"Pray, Jeff" > > >> >>><Jeff.Pray@METROKC.GOV> >>>>>>>CC: "Dunn, Reagan" <Reagan.Dunn@METROKC.GOV>,"Cheatum, Tim">>>> >>><Tim.Cheatum@METROKC. GOV>, ''Townsend, Steve"> > >> >>><Steve. Townsend@METROKC. GOV>, "Hammond, Terry 11 > > >> >>><Terry.Hammond@METROKC.GOV>,"Scharer, Bill">>>> >>><Bill.Scharer@METROKC.GOV>, "Moore, Bernard">>>> >>><Bernard.Moore@METROKC.GOV>,"Dykeman, Mike">>>> >>><Mike.Dykeman@METROKC.GOV>,"Warden, Stephanie">>>> >>><Stephanie.Warden@METROKC.GOV>,"Adams, Paula">>>> >>><Paula.Adams@METROKC.GOV>,"Ombudsman" > > >> >>><Ornbudsman@METROKC.GOV>,"Ortiz-Olguin, Cathy">>>> >>><Cathy.Ortiz- Olguin@ME'I'ROKC. GOV>, !! Sanders, Jim"> > >> >>><Jim. Sanders@METROKC. GOV>' "Gallagher, Wendy" > > >> >>><Wendy.Gallagher@METROKC.GOV>, "Spohr, David 11 > > >> >>><David.Spohr@METROKC.GOV> >>>>>>>Subject; RE: COMPLAINT: Evendell L03RE038 and Nichols Place L03P0015 > > >> >>>Date: 1'hu, 13 Jul 2006 14: 45: 37 -0700 > > >> >>> >>>>>>>Ms. High- >>>>>>> >>>>>>>Our office is preparing a written response to your email regarding the Evendell/Nichlos Place projects. David Spohr is out of the office until July 27. will coordinate with Mr. Spohr regarding the purpose and the agenda of the August upon his return. »> > > >> > > >> > > >> > > >> > > >> > > » > > >> > > >> > > >> > > >> > > >> > > » > > >> >>>Joe Miles, P.E. >>>King County Land Use Services Division Director Dept. of >>>Development and Environmental Services >»(206) 296-7179 >>>joe.miles@metrokc.gov >>>wwv,.r.metrokc.gov/ddes »> >>>-----Original Message----- >>>From: Highlands Neighbors >>>[mailto:highlands_neighbors@hotmail.com] >>>Sent: Thursday, July 13, 2006 1:37 PM >>>To: Pray, Jeff Our office 10th meeting >>>>>>>Cc: Dunn, Reagan; Cheatum, Tim; Townsend, Steve; Miles, Joe;>>>> >>>Hammond, Terry; Scharer, Bill; Moore, Bernard; Dykeman, Mike;>>>> >>>Warden, Stephanie; Adams, Paula; Ombudsman; Ortiz-Olguin, Cathy;>>>> >>>Sanders, Jim; Gallagher, Wendy >>>>>>>Subject: RE: COMPLAINT: Evendell L03RE038 and Nichols Place > > >> >>>L03P0015 > > >> >>> >>>>>>>Good Afternoon, All! > > >> >>> >>>>>>>We hope everyone had a safe and happy holiday. It has now been another two weeks since last communication from you on this matter, so we thought we better check in. > > >> >>> > > ?> >>>::1 the meartirne, J ha·,,.re had severa, prod'...1cti1..re conversa-:ior..s with >>Mr.Spohr. He has set up a neetir~q ·w·i::h -c.s :"or Auge,st 10. (7pm, Lord of Li.::-e Church at the corner of: SE 128th and 160th Ave SE). He ~ni:orrrs ;ne that he has ext.er..ded invitations to DDES personnel, but had not yeL beer, advised of attendees. > > >> >>> >>>>>>>Our questions t.oday are: > > >> >>>-W~'1at is the action item list from the meeting described below? > > >>>>>-What is the asscciated timeline for those action items? > > >>>>>-Who will attend the meeting on August 10th? > > >> >>> >>>>>>>We look forward to learngin the answers soon. > > >> >>> >>>>>>>Thank you, >>>>>>>Gwendolyn High > > >> >>> > > >> >>>C.A.R.E. -Citizens' Alliance for a Responsible Evendell > > >> >>> ... doing what we can, with our neighbors, for our community ... > > >> >>>v.rww.highlandsneighbors.org > > >> >>> > > >>>>>>From: 11 Highlands Neighbors" <highlands_neighbors@hotmail.com> > > >>>>>>To: Jeff.Pray@METROKC.GOV > > >>>>>>CC: Reagan.Dunn@METROKC.GOV, Tim.Cheatum@METROKC.GOV,> > >> >>> >Steve.Townsend@METROKC.GOV, Joe.Miles@METROKC.GOV,> > >> >>> >Terry.Hanunond@METROKC.GOV, Bill.Scharer@METROKC.GOV,> > >> >>> >Bernard.Moore@METROKC.GOV, Mike.Dykeman@METROKC.GOV, > > >> >>> >Stephanie.Warden@METROKC.GOV, Paula.Adams@METROKC.GOV,> > >> >>> >Ombudsrnan@METROKC.GOV, Cathy.Ortiz-Olguin@METROKC.GOV,> > >> >>> >Jim.Sanders@METROKC.GOV, Wendy.Gallagher@METROKC.GOV > > >>>>>>Subject: RE: COMPLAINT: Evendell L03RE038 and Nichols Place > > >> >>> >L03P0015 > > >>>>>>Date: Fri, 30 Jun 2006 13:25:43 -0700 > > >> >>> > > > >>>>>>Dear Mr. Pray, > > >> >>> > > > >>>>>>Thank you for your status update. As you may well expect, these issues are of intense interest to our community and inquiries to CARE on the matter have been voluminous. I am glad that we are now able to forward your update to our members before the long holiday weekend. > > >>>>>>Particularly in light of the fact that insufficient, ineffective or non-existent corrununication between your colleagues and the impacted residents is one of the chief concerns identified in our complaint; your update appears to indicate progress that we all can appreciate. > > >> >>> > > > >>>>>>We hope for continued progress and look forward to learning the action items and timetable that result from the meeting you describe below. > > >> >>> > > > >>>>>>Have a lovely holiday, > > >>>>>>Gwendolyn High > > >> >>> > > > >> >>> >C.A.R.E. ~ Citizens' Alliance for a Responsible Evendell > > >>>>>> ... doing what we can, with our neighbors, for our community. > > >> >>> >www.highlandsneighbors.org > > >> >>> > > > >>>>>>>From: "Pray, Jeff 11 <Jeff.Pray@METROKC.GOV> > > >>>>>>>To: "Highlands Neighbors" <highlands_neighbors@hotmail.com> > > >>>>>>>CC: "Dunn, Reagan" <Reagan.Dunn@METROKC.GOV>,"Cheatum, Tim">>>>>>> >><Tim.Cheatum@METROKC.GOV>,11 Townsend, Steve">>>>>>> >><Steve.Townsend@METROKC.GOV>, "Miles, Joe">>>>>>> >><Joe.Miles@METROKC.GOV>,"Ham..11ond, Terry">>>>>>> >><Terry.Hammond@METROKC.GOV>,"Scharer, Bill">>>>>>> >><Bill.Scharer@METROKC.GOV>, 11 Moore, Bernard 11 > > >> >>> >><Bernard.Moore@METROKC.GOV>,11 Dykeman, Mike">>>>>>> >><Mike.Dykernan@METROKC.GOV>,11 Warden, Stephanien> > >> >>>>><Stephanie. Warden@METROKC. GOV>, "Adams, Paula''> > >> >>> ><Paula.Adams@METROKC.GOV>,"Ombudsman 11 > > >> >>> >><Ornbudsman@METROKC.GOV>,"Ortiz-Olguin, Cathy">>>>>>> >><Cathy.Ortiz-Olguin@METROKC.GOV>,"Sanders, Jim 11 > > >> >>> >><Jim. Sanders@METROKC. GOV>, 1'Gallagher, Wendy"> > >> >>> >><Wendy. Gallagher@METROKC. GOV> > > >>>>>>>Subject: RE: COMPLAINT: Evendell L03RE038 and Nichols Place > > >> >>> >>L03P0015 >>>>>>>Date: > > >>>>>>>Fri, 30 Jun 2006 :2:21:05 -0700 > > >> >>> » > > >> >>> >>~S. High, > > >> >>> » > > >> >» >>On behalf of DDES staff involved in the respor1se to youY concerns, p~ease be advised that a meeting with all concerned staff has been requested by tLe ~and Use Service[:> Division Director, Joe Miles. The meeting wilJ. occur shortly after the upcomi::-ig holiday. I'm sure you will agree the concerns you describe cover a variety of disciplines acd issues. The meetiGg i.s intended to assure we address them comprehensively in our reply to t::--ie Highland Neighbors. > > >> >>> >> > > >>>>>>>In the interim, please be assured that the Building Inspections Sec'.:.ion (particularly Bernard Moore and Terry Hammond), with the assistance of Land Use Inspections (particularly myself and Tim Cheatum), have been interacting on a daily basis regarding the drainage and grading issues related to the plats and the building permits. Terry is the field person for the issues related to the building permits and to my understanding has been in contact with the permits' applicant regularly over these past weeks. > > >> >>> >> > > >>>>>>>One of the issues in your list of concerns involves the placement of street trees required by plat conditions. For your information, plat conditions require the trees be installed within one year of recording. Evendell will reach the end of that period later this surmner; Nichols Place will reach the end of that period this fall. Both projects have the required financial guarantees and agreements in place to assure this work will occur. > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> >>> >>> >>> »> >>> >>> »> »> »> >>> >>> >> >>Thank you, >> >>Jeff Pray >>Senior Engineer >>KC DDES Land Use Inspections >> >>-----Original Message----- >>From: Highlands Neighbors >>[mailto,highlands~neighbors@hotmail.com] >>Sent, Friday, June 23, 2006 3,08 PM > > >>>>>>>To: Dunn-, Reagan; ZZGrp, Hearing Examiners Web Support;>>>>>>> >>Cheatum, Tim; Pray, Jeff; Townsend, Steve; Miles, Joe;>>>>>>> >>Hammond,>> > > >>>>>>>Terry; Scharer, Bill; Moore, Bernard; Dykeman, Mike; Warden,>>>>>>> >>Stephanie; Adams, Paula; Ombudsman > > >>>>>>>Subject, COMPLAINT, Evendell L03RE038 and Nichols Place > > >> >>> >>L03P0015 > > >> >>> >> > > >>>>>>>To Whom it May Concern: > > >> >>> >> > > >>>>>>>Citizens' Alliance for a Responsible Evendell is dismayed to report that practically every single adverse effect that we predicted in our interventions and appeals as possible results of the Evendell and Nichols Place projects has indeed come to pass. > > >>>>>>>The damage and expense that has been inflicted on neighboring residents has been unnecessary, and in every case, avoidable. We submit the attached complaint and request a speedy inquiry and resolution. >>>>>>>>> > > >>>>>>>Work has begun in earnest on the adjoining Liberty Grove/Contiguous projects. At the very least we hope that review of these issues will minimize additional impact and expense. > > >> >>> >> > > >>>>>>>Additional photos and testimony will be submitted as soon as possible. > > >>>>>>>Technical difficulties prevent their submission today. > > >> >>> >> > > >>>>>>>Thank you, > > >> >>> >> > > >>>>>>>Gwendolyn High > > >> >>> >>presidnet > > >> >>> >> > > >> >>> >>C.A.R.E. -Citizens' Alliance for a Responsible Evcndcll > > >>>>>>> ... doing what we can. with our neighbors, for our community ... > > >> >>> >>www.highlandsncighbors.or > > ><< 2006080l _Evcndcll_NicholsPlaceComplaint.doc >> RE: Follow Up: Evendell/Nichols Place Meeting of August 10, 2006 From: Dykeman, Mike (Mike.Dykeman@METROKC.GOV) Sent: Fri 9/15/06 4:59 PM To: Highlands Neighbors (highlands_neighbors@hotmail.com); Warden, Stephanie (Stephanie.Warden@METROKC.GOV) Cc: kurt@soundbuilthome.com; deb@soundbuilthome.com; Spohr, David (David.Spohr@METROKC.GOV); Townsend, Steve (Steve.Townsend@METROKC.GOV); Moore, Bernard (Bernard.Moore@METROKC.GOV); Miles, Joe (Joe.Miles@METROKC.GOV); Nguyen, Viet (Viet.Nguyen@METROKC.GOV) Ms. High and the Highlands Neighbors, I apologize for the delayed response. I have experienced an unexpected family emergency which has occupied a lot of my time the last couple of weeks. We have continued to make progress on the items that we discussed at the community meeting: Occupancy Approval: DDES committed to withholding occupancy of the new houses in the Evendell/Nichols Place plats until the drainage requirements for the individual lot is approved. The drainage requirements for individual lots are the connection all roof downspouts and yard drains to the main storm drain in the street. I corrunitted at our meeting to requiring a flow test for each required drain to make sure that water entering that drain flows to storm drain in the street. Subsequently, DDES has approved occupancy for a number of residences. The DDES inspector has verified that required roof and/or yard drains are in place and witnessed a successful flow test from each required roof and/or yard drain for the individual lot prior to granting final inspection approval. Special Drainage Conditions: I discussed in our meeting that there are two drainage sub-basins in the Evendell plat. The ridge dividing the.sub-basins occurs in lots 15 through 20. A drainage variance was approved to allow the water from the new impervious surface created in the westerly sub-basin to drain into the storm system in the easterly sub-basin. This is accomplished through roof and/or yard drains on each lot that drain to the storm drain in the street. There are no provisions in the variance for collection of rain water on the yards in the westerly sub-basin. After the complaint from the Thorbecks about water running on to their property during construction, DDES asked Sound Built Homes to construct an earth berm to keep water on the construction site. This was accomplished. Subsequently, Sound Built Homes has submitted a plans change to construct a permanent shallow swale along the west boundary of Evendell to collect any yard drainage in the western sub~basin. The swale slopes to the south and drains into a yard drain at the low point. The yard drain is piped to the storm drain in the street. An Easement and Covenant for Drainage has been recorded for the swale, yard drain, and drain pipe. This facility has been installed and a flow test from the yard drain shows that it drains to the street. The Thorbecks have raised concern about future landscaping by individual home owners altering the drainage swale. As previously noted, the Easement and Covenant of Drainage is recorded on the titles of the affected lots. DDES will inspect the swale for compliance at final inspection. After final inspection, any violation of swale drainage requirements should be referred to the Code Enforcement Section at 206-296-6680. Setback Violation: Concern was raised that the house on lot 19 in the Evendell plat is too close to the Thorbecks property. The zoning code requires a 5 ft side yard setback to the foundation wall in this circumstance. The zoning code allows some projections within this required setback. The building code allows construction up to the property line with 1 hour fire resistive construction required and no openings allowed for walls closer that 3 ft to the property line, which is not the case here. DDES requested that Sound Built Homes provide a survey showing the property lines, foundation outline and setback lines for lot 19. This survey was completed and made available at our meeting. The survey shows that the foundation is 5.09 ft from the Thorbeck's property line. The survey a+so shows the setback from the lot 20 property line to be 4.90 and 4.91 ft, which is too close. Several options are available for addressing the setback violation, including a zoning variance. Sound Built Homes has applied for a zoning code variance pre-application meeting under activity A06PM356. The meeting is scheduled to be held September 19th. DDES has informed Sound Built Homes that permanent occupancy will not be allowed until the setback violation is satisfactorily resolved. A '::'.'emp0rary Certiticate of Occupaccy will be grar.ted when a ~-1 other requ 1 rcmenls have been met. Damage to NeighDoring Proper~::..es: Several ncighDors to the Ever:dell/Nichols Place plats gave testimony as to water damage to their properties as a :::::-esult of run off from the plats durinCJ a heavy rain storm last wint,er. DDES representatives at the meeting expressed regrel over the damage that anyone experienced as a resul.t of this 8Vent. T.r,1e do our best eLcourage co:npl .i ance wit.h drainage requirements on site d:..1ring construction. We also said that. Sound Built HO::",es has the responsibility for compliance wi__th the codes. Deb Hol:.cr~bcck of Sound Built Homes was asked with ·w·hom at Sound Built to discuss a damage claim from water damage durir.g lhis storrr. event. Deb gave the contact name of Kurt Wilson who can be reached at 253-377-7147. Improved Corrununication: The Highlands Corrununity expressed concerE that there is no formal public process for them to know what is going on after permits are issued and construction is started. DDES recognizes this concern and is available to include corrununity representatives in the pre-construction conference and/or attend a community meeting to provide information prior to the start of construction for any future plats in the Highlands area. DOES will contact all parties of record in this regard. Improve Construction Phase Oversight: DDES representatives explained at our meeting that we have a high degree of construction overs~ght from the Land Use Inspection and the Building Inspection Section. We have numerous required inspections and are at a construction site often. However, we are not staffed nor do we have the responsibility to be at a site continually and observe all construction activities. We do want to respond to community concerns and complaints and appreciate contact from the community if violations occur during non working hours or when we are not able to be on site. We have responded many concerns and complaints regarding the development of the Evendell/Nichols Place plats by phone, e-mail and site visits. We have met neighbors on site a number of times. Our goal is to ensure compliance with the codes. We feel that we have done that or are in the process of doing that with each of the issues that have been raised. There are those who would like DDES to do more than the code requires and we can not do that. There are those who would like us to require less and we will enforce the code to the best of our ability. We gave out a list of names and phone numbers at our meeting for contacts at DDES. I will include them in this communication: Building Issues: Mike Dykeman 206-296-6761 Bernard Moore 206-296-6762 Land Use Issues: 206-296-71'79 Joe Miles Steve To1.v11send 206-296-7204 Again, we at DDES do care and we are dedicated to doing our jobs well. Please feel free to contact any of us about any additional concerns or questions that you may have. Mike Mike Dykeman Division Director Building Services Division Department of Development & Environmental Services 900 Oakesdale Avenue Southwest Renton WA 98055-1219 Phone 206-296-6761 Fax: 206-296-7212 PS Several people met with Joe and me after our meeting to address individual concerns. We are working on these issues on a case by case basis. -----Original Message----- From: Highlands Neighbors [mailto:highlands_neighbors@hotmail.com] Sent: Tuesday, September 12, 2006 12:59 PM To: Warden, Stephanie Cc: kurt@soundbuil thome. com; Dykeman, Mike; deb@soundbuilthorr,e. con; Spohr, David; To\l!Dsend, Steve; Moore, Bernard; Miles, Joe; Nguyen, Viet Subject: RE: Follow Up: Evendell/Nichols Place Meeting of August 10, 2006 Hello, Ms. Warden, It was good to chat with you last Thursday at the UAC forum. I was encouraged that you initiated a followup conversation on our Evendell/Nichols Place complaint and by your offer to ~nvestigat.e t_r,c holdup on t.he progress report we have been expecting for jusl abo-,1t a month. Thal seems to be the !flinimum turn around tirr.e for any substantive communication f:!:'."o:n your sta::::f to the residents of ou~ community. Strangely, as evidenced by Ms. Thorbeck'.s e:r.ail below, such a I..,OS is not consiste:i.t across c1ll of DDES cornm'Jnications/interactions. The words we beard at the August 10th meeting were all quite nice. We only wish you might effect some action to actually make them reel. We look forward to hearing the DDES plan of action to address the issues raised agai:-i at the August 10 meeting. Thank you, Gwendolyn High -president C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what we can, with our neighbors, for our community ... www.highlandsneighbors.org >From: "Thorbeck, Penny" <thorbeck. p@ghc.org> >To: "Highlands Neighbors" <highlands_neighbors@hotmail.com> >Subject: RE: Evendell/Nichols Place Records available for review >Date: Tue, 12 Sep 2006 08:06:51 -0700 > >That's interesting. We have neighbors in our backyard in the Nichols development. those plats were approved for occupancy without drainage resolution! > >Penny K. Thorbeck >Tertiary and OON Care Management >206-901-6124 >8-600-6124 > >CONFIDENTIALITY NOTICE: I guess >This message and any attached files might contain confidential information protected by federal and. state law. The information is intended only for the use of the individual{s) or entities originally named as addressees. The improper disclosure of such information may be subject to civil or criminal penalties. If this message reached you in error, please contact the sender and destroy this message. Disclosing, copying, forwarding, or distributing the information by unauthorized individuals or entities is strictly prohibited by law. >From: uDykeman, Mike" <Mike.Dykeman@METROKC.GOV> >To: "Highlands Neighbors 11 ><highlands_neighbors@hotrnail.com>,<deb@soundbuilthome.com>,"Spohr, David" ><David.Spohr@METROKC.GOV>,"Townsend, Steve" ><Steve.Townsend@METROKC.GOV>,"Moore, Bernard" ><Bernard.Moore@METROKC.GOV>,"Miles, Joe" <Joe.Miles@METROKC.GOV>> CC: "Warden, Stephanie" ><Stephanie.Warden@METROKC.GOV>,<kurt@soundbuilthome.com> >Subject: RE: Follow Up: Evendell/Nichols Place Meeting of August 10, >2006 >Date: Wed, 16 Aug 2006 16:36:40 -0700 > >Gwendolyn, it was a pleasure meeting with you and the corrununity group last Thursday evening. We have been working on the issues that were identified at our meeting. I am out of the office Thursday and Friday. We will provide you with a progress report next week. >Mike > >-----Original Message----- >From: Highlands Neighbors [mailto:highlands_neighbors@hotmail.com] >Sent: Wednesday, August 16, 2006 3:01 PM >To: deb@soundbuilthome.com; Spohr, David; Townsend, Steve; Moore, >Bernard; Dykeman, Mike; Miles, Joe>Cc: Warden, Stephanie; kurt@soundbuilthome.com >Subject: Follow Up: Evendell/Nichols Place Meeting of August 10, 2006 > >Dear All, > >I apologize for the long delay in sending this message. I have been ill. > .:-F__:_r.:--,t of all, we would like Lo express our ::.!'"1anks fo::c your att.enclar.cc lasl week. 13..vc: only 2 blocks from tl:c meeting location, a!1d I walked in :;:,.y front cioor at 10 to 10pm. I'm qucssing that each oi you had an even later evening, > >As Mr. Spohr expressed there, after so long a time for issues to remain octstanding, it would be unreasonable to expect full resolution in one e:i.counter. This meeting really only had ti::-ie to !1ash through w:lat has gone before. Nonetheless, ',Ve had to start somewhere, and I believe the conversation is off to a good start. > >A few key quotes stand out in blazing, 3-foot-tall letters in rr~ mind: > >Joe Miles: ''We, and our staff, are dedicated to doing our jobs well." >Mike Mykernan: "We do care." >Deb Hollenbeck: "We are committed to being good neighbors. We want Lo do the right thing." > >In light of these quotes, we ask, "What do you propose?" > >Right off, I want to be clear that we understand that the answers to that question will surely mean very different things to DDES and Sound Built. To clarify: > >-What does Sound Built propose to "make things right" for the residents negatively impacted by the construction activities at the Evendell and Nichols Place projects? >Diane Kezele (water runoff, trees, septic system) Dave & Penny Thorbeck flooding, setback issues, encroachment, drainage improvement expenses, structural damage) Jay Hill {flooding, trees, structural damage) Mary Ann Huniu (flooding, drainage, $15K basement damage} Marsha Rollinger flooding) Claude Stachiwiak (drainage} > >-What does DDES propose to do to: >Improve conununication with residents? >Improve construction phase oversight in order to minimize future >setback violations, flooding events, encroachments and collateral >structural damage? > >We are encouraged that the conversation has finally been engaged. We >look forward to continued productive discourse, and hope for honorable >resolution of all these issues. > >Thank you, >Gwendolyn High -president > >C.A.R.E. -Citizens' Alliance for a Responsible Evendell ... doing what >we can, with our neighbors, for our community ... >www.highlandsneighbors.org > > > I \ • t ;. t \ l {. ,, . ..~ I ( ,. ~" . ' 1• .. , ' / ... --':~·--:~ °' ~.,r· -~~ .. ' ~' ' "' ' .•. ~ ' \ • ... ·~ : •t .'·' ' •• [,;I ' '., \} ~ -, ·: .. ' : . ~ . ( :· ·: '-~ -~. .... ".; ; I , t; k•' .. :t .;: ·ir ~ • '4,· .... ' ' ~ :' I :'t '· ; k ' .• .. ,). • f . ' . : ~· . ' -~ 1:1( -~~ .• ~ ' ~ • • ... ~ t • .. •. ' •. l '!· ; . . i l • . " ., ~ f .. : i .. ' :,, . ';!( __ '·. " \' :·· . ' \ • I . :~ .• j:];9 1 ; ,1 ,. ., •i ' } .. r ·,. • I l I I , • l ' ' •, l '.:,IA. :'.--61.·13 i ;,11;, ·:.L;RB ,~·-- _1_1E_ 1h '..._( 6+00 1-~-- FOUND MIC '.\ i i \ ' :.LI ' ' j : I 11 ' ' T ' I I _I ///////////////// ///////////////// ///////////////// ///////////////// ///////////////// O.OO'N 9,922 SF REDUCED ENHANCED BUFFER 2,551 SF WETLAND CREATION 1,031 SF WETLAND IMPACT 4,512 SF WETLAND FOUND REBAR SMASHED C'\P O.OO'N Al\!O 0.06'W _.-6 WOOD r-Tl\iCi- f I {J-J ·--· t-UUNU 1-<t.J:iAK LS# 10219 ~-0.01'S 0.11'W ANLF-<CAV . -u.O 0.1 ~ 4' CYC . ()-_/ 30' 30' 30' w Ul .I !J II ' ~ 30' '--·{_)- ' I/ '! I.L. · 1. ; . I . L. REE 0 204060 -. . JIIIIIIIIIIIIII SCALE: 1"=40' 80 Git}¥ G! 1\-"""'·'"" Planrnng D1vis1on JAN X ,11012 Sewall Wetland Consulting, Inc. 1103 West Meeker Street Ste. #101, Kent, Wa 98032 253-859-0515 Fax 253-852-4732 (J) z 0 (J) > w et: <J <J <J <J Job No. A5-209 Designed by: ES Drawn by: CML Checked by Date: OCT. 2011 SHEET W-1 OF W-3 I I I I I I l l \ I 0 .· .~. ' vurr ~-.. ~ PROPOSED GIMDING PLAN LU -,~---,z.--J_.)Lf--~. I 1,:1·,_)./o " -"---------- \ ~-~ 25' LEVEL -SPREADER WETLAND --496 -8--'i'--·----\ ELEVA Ttq_N '· \ /' -) 1 494 \ ,_./ B-6 B-12 E\/EL / OFR_./ I 7 s 14 VI ii ,// . . A c~pJ-IA I T . . . ... . S. I ()f\ u O__ I Nf,2····· ':J ~ ORA, INET W~l'." (C: V ~3 \_ {] I I ~ 0 ll) • " 0 • • • • ' I ' . !w - BUFFER ENHANCEMENT PLA/1/T/NG LIST WETLAND CREATION PLANTING LIST QNTY PLANT NAME TREES 0 g Big Leaf Maple Acer macrophyllum --- (G) 10 Douglas Fir _,, Pseudotsuga menziesii ·-- (c) 6 Western Red Cedar ~·,,C Thuja p/icata SHRUBS (v) 21 Vine Maple Acer circinatum r-----··----- @ 21 Hazelnut Cory/us cornuta GJ 23 Indian Plum ' Oemleria cerasiformis I (y 20 Sala! Gau/theria sha/lon - Co) 25 Snowberry -· . SvmphoricarpQ<i a/bus CS) 25 Nootka Rose Rosa nutkana . -· -·· 8:) 12 Salmonberry I Rubus spectabi/is 8 25 Red-flowering Currant Ribes sanauineum ---· EB 20 Evergreen Huckleberry Vaccinium ovatum r 4''x6"x6·posl -2" x 6" x 8' rail (Typ.) SIZE SPACING 2 gal. as shown -~ 2gal. as shown 2 gal. as shown 2gal. as shown 2gal. as shown . 2 gal. as shown 2gal. as shown ·--·- 2 gal. as shown 2gal. as shown 2 gal. as shown -- 2ga/. as shown 2ga/. as shown Balled & burlapped or containierized plant as specified QNTY PLANT NAME SIZE SPACING TREES 8 7 Scou/er Willow 2gal. as shown Salix scou/eriana 0 10 Quaking Aspen 2 gal. as shown Popu/us tremu/oides -,~, Sitka Spruce 2 gal. as shown ~ 7 Picea sitchensis t""", 7 Western Red Cedar 2 gal. as shown \,SJ Thuja p/icata SHRUBS G @ (i) -···-- @ 8 Red-osier Dogwood Cornus stolonifera 2ga/. -. g Pacific Ninebark 2gal. Physocarpus capitatus - 13 Salmon berry 2 gal. Rubus spectabi/is - 18 Black Twinberry Lonicera involucra 2 gal. 4 LARGE WOODY DEBRIS (TYP.) 16' length ( min.) 17" diam. ( min.) as shown as shown as shown as shown Preferred species Red Cedar wlbranches intact, may use native conifers removed during site grading. - ~-~~~. ~~-···-~~~~· ~f~- 18" Cut & remove burlap from lop 112 of bail (burlap to be roffable) -2 112" min. Mulch or sterile straw for spring planting, woad chips for fall planling. 2" (TYP) --ii 1-1 I I--__ j-_,. __ 1._-1 , 11 11 r==111_ 111 111 1 '18' 111 , 1 111 ::111 -111 111 111-c ' ~--_1 _I I I IJ_l 11 111 _111 ._I 1,1-__ __,.6~" m=m. drain rock d I l:c:.:I I l=I I ICJJJ-111 111-111-11 G7 Note: Install habitat fence as shown Finish grade .. 111 • " c;';l[~lliiii!lsi!!!iiilill:m 3"1 ~-•: _,_·~ -=I ~I 6" 2 x's Root I .. BALL (MIN) • Top soil & fertilizer Cut & remove burlap from top 1/2 of ball (burlap to be rot/able) Top soil ,..._~ fertilizer PROPOSETJ PLAN11NG PLAN -LU '" f L JU ~ I-1-.-1 .._}/o ':i l ., .... -4 .; -----... .. 4 ,· " ' "'-4-__ q'"- • • HZ 0 0 HZ • T~AC'1 E+ s-·4SENS IVE KREA + I 0.1. VVAT---\-w -0 EXISTING TREE LEGEND • FIR TREE ~ CHERRYTREE ~~ \ll MAPLE TREE * HAWTHORN TREE ~ ALDER TREE (-"' ~)~ COTTONWOOD TREE ~. ~ CEDAR TREE • HEMLOCK TREE 6" berm (typ) '----2 1 /2" min. Mulch or sterile straw for spring planting, wood chips for fall planting. Cut & remove bu"ap from top 1 /2 of ball (burlap to be rot/able) --2 x root ball (min) ...... - 6" berm (typ.) 2 1/2" min. Mulch or sterile straw for spring planting, wood chips for fall planting. Top soil & fertilizer FENCE DETAIL SHRUB PLANTING DETAIL CONIFEROUS TREE PLANTING DETAIL TREE fJLANTING DETAIL NOTTO SCALE NOTTO SCALE NOTTO SCALE NOTTO SCALE TEMP. EROSION & SEDIMENTATION CONTROL NOTES f. THE IMPLEMENTATION OF THESE TESC Pl4NS & THE CONSTRUCT/ON, MA/NrENN1'CE, REPLACEMENT & UPGRADING OF IHESE TESC FA Gil/TIES IS THE RESPONSIBILITY OF THE APPUCANT/TESC SUPER'!ISOR UNTIL ALL CONSTRUCT/ON IS APPROVED FILTERFABR/Cilv\TER!AL -- 2. THE BOUNDARIES OF THE CLEARING UM/TS SHOWN ON THIS PIAN 8HAll BE CLEAHL y MARl<ED BY Sil T FENCE PRIOR ro CONSTRUCTION. DURING THE CONSTRUCT/ON PERIOD, NO DISTURBANCE BEYOND THE CLEARING l/1./ITS SHALL BE PERMITTED. THE CLEANING l!MITS SHALL BE MAINTAINED BY THE APPLICANT!TESC SUPERVISOR FOR THE DURATION CF CONSTRUCT,'ON. AFTER GRASSES HAVE BECOME ESTABLISHED, Sil T FENCING,U4 Y BE REMO'IED. :J THE TESC FACILITIES SHOWN ON THIS PLAN MUST BE CONSTRUCTED PRIOR TO OR IN CONJUNCTION WITH ALL CLEARING & GRADING SOAS TO ENSURE THAT THE THANSPORT OF SEDIMENT TO SURFACE WATERS. DRAINAGE SYSTEMS & ADJACENT PROPERTIES IS M1NIMIZED. 4. Tl!E TESC FAC/l/TIES SHOWN ON THIS PIAN ARE Tf/E MINIMUM REQU'REMENTS FOR ANTIC/TAPED SITE CONDITIONS. DUR/NG THE CONSTRUCTION PEH./OLJ, THESE TESC FACILl/"IES SH,1LL BE UPGRADED ;\$ NEEDED FOR UNEXPECTED STORM EVENTS & MOD/F!EO TO !lCCOUNT FOR CHANG/NG SJTE CONDITIONS (EG., RELOCATION OF DITCf!ES & S/l T FENCES, Ere. FILTER FABRlCMATERIAL 60' WIDE HOLLS - USE STAPLES OR )-¥,'RE RINGS TD ATTACH FABRIC..' TO ~WRE 2'X4'WOOOPOSTS. STD. OR BETTER----. OR EQUAL. AL TERNA TE , '- STEEL POSTS PROVIDE J/4 "-f.5" WASHED Gfv\ VEL BACKFILL IN TRENCH & ON BOTH SITES OF FILTER FABRIC ON Tl-IE SURFACE 2" BY 2" BY f4 GA. WIRE - FABRIC OR EQUW II~--~'·--·· M4X. BUH.VIN NATIVE GROUND SECTION VIEW FILTER FABRIC FENCE DETAIL NOTTO SCALE PROFILE VIEW NOTES- /. INSTALLATION SHALL FOLLOW THE MANUFACTURER'S RECOMMEND!\ TIONS. 2. POSTSSHALLBEINSTALLEDSOTHAT A MIN. OF 2' EXTENDS ABO\iE Th'E GROUND WITH A MIN. OF 2'-6' EMBEDMENT. 2'MtN. FABRIC EXPOSURE 2'·1}' 0 10 20 30 -· ··-SCALE.· 1" = 20' Ul z 0 Ul ' .-> w er: 40 PLANTING NOTES: • Planting areas shall be cleared of Non-native invasive species such as Himalyan Blackberry, Scotch broom, and purple /oosestrife. <] <] <] <] • Newly installed plants must be flagged with high visibility flagging. CLEARING AND GRADING NOTES: • • • • Biologist to be on-site during wetland creation grading. Planting areas shall be cleared of Non-native invasive species such as Himalyan Blackberry, Scotch broom, and purple /oosestrife. Grading Requirements .A person who clears, grades or oth11rwise disturbs a site shall provide erosion and sediment control that prevents, to the maximum extent practicable, the transport of sediment from the site to drainage facilities, water resources and adjacent properties. Erosion and sediment controls shall be applied as specified by the temporary erosion and sediment control measures and performance criteria and implementation requirements in the Surface Water Design Manual. Seasonal Limitations: From October 1st through April 30th, which is the seasonal limitation period, clearing and grading shall only be permitted if shown to the satisfaction of the Director that runoff leaving the construction site will comply with the erosion and sediment control measures and performance criteria and implementation requirements in the Surface Water Design Manual through a combination of the following: a. Site conditions including vegetative coverage, slope, soil type and proximity to receiving waters; and b. Proposed limitations on activities and the extent of disturbed areas; and c. Proposed erosion and sedimentation control measures. CRITICAL AREA DO NOT DISTURB WETLAND SIGN NOTES Glue sf}· 11 to 1/2" CDX plywood and attach o 8' 4"x.4" cedar or pressure lreate post wilh 5!16"x3" ,ag bolt. Set post minimum 3' below grade; 4".x4" cedar post to be set in concrete. Wetland sfqn to sit at approximately 5' height alJove llnlsh grade, The wetl,111dlstrei)m sign shall be posted at the boundary between the Sensitive Area Buffer. Su/back Area or Setback Tract and the Building Setback Area. WETLAND AREA ENlERGENT SEED MIX (Creation area to be seeded) 20% Slough Sedge ( Cc1rer ob111tpta) 20% Northwestern Mannagrass ( C'(yce1ic1 e!c1tc1) 20% Dagger-leaf rush ( Jt11zc·1Lr e11sijo!1i1s·) 20% Slender rush ( JttFtcus· te11111:S·) 20% Small-fruited Bulrush (Scirpus microcarpus) Seeding Rate: 1/b/2000sq. feet BUFFER AREA SEED Nll/Y (All buffer areas disturbed during construction) 25% Redtop Bentgrass ( Ag1·0,rt1:S· alba ) 25% Perennial Rye ( Lo!ittFJt perenne) 25% Idaho fescue ( Jiert11ca idahoen,rir) 25% Red Fesce ( Fest11cc1 r11b1·a) FOR MORE INFORMATION CONTACT YOUR CITY OR COUNTY One sign shaJ! be posted 11aer lot for ever:v 150' or Sensitive Area Butter and shall be stationed in a prominent location i e. at the closest point to the proposed develoP,.ment. Signs may also be attached securely to fences. Seeding Rate: 3/b/1000sq. feet WETLAND SIGN DETAIL Sewall \Netland Consulting, Inc. NOTTO SCALE 27641 Covington Way SE #2, Covington, WA 98042 253-859-0515 Fax 253-852-4732 Job No. A5-209 Designed by: ES Drown by:_ TS Checked by: Dote: OCT. 2011 SHEET W-2 OF W-3 ' I ' I I j 1.0 MITIGA"l'ION CONCEPT 1.1 CRITICAL AREA IMPACTS The proposed project is the development of a residential short plat. The project proposes to fill the 1,031 sf Wetland A. As mitigation for impacts to the wetland, the project will create 2,557 sf of new wetland contiguos with Wetland B, and enhance 9,922 sf of Wetland B buffer. The wetland creation area provideas an approximate 2.5:1 mitigation ratio. 1.2 MITIGATION GOALS 1.2.1 Create 2,557sf of new wetland along southern wetland boundary. 1.2.2 Enhance 9,922sf of buffer with native tree and shrub species. 1.3 NATIVE GROWTH PROTECTION AREA As a condition of any development permit, the property owner shall be required to create a separate native growth protection area containing the areas determined to be wetland and/or wetland buffer, including areas of wetland crealion and buffer averaging. Native growth protection areas shall be established pursuant to RMC 4-3-050E4. 2.0 CONSTRUCTION SEQUENCE The construclion sequence of this project will be implemented as follows: 2.1 Pre-construction meeting 2.2 Construction staking 2.3 Construction fencing and erosion control 2.4 Grading of Creation Area 2.5 Stabilization of mitigation area 2.6 Plant material installation 2. 7 Permanent fence and sign installation 2.8 Construction inspection 2.9 Agency approval 2.1 O Monitoring inspection and reporting 2.11 Silt fence removal 2.12 Project completion 2.1 Pre-construction Meeting A pre-construction meeting will be held on-site prior to commencement of any grading, to include the Owner's biologist, the Landscape Installer, the Owner and the City. The approved plans and specifications will be reviewed to ensure that all parties involved understand the intent of the construction documents, specifications, site environmental constraints, sequences, and inspection requirements. 2.2 Construction Staking The limils of the mitigation area will be marked in the field prior to commencement of construction aclivities to ensure that all plantings will be installed within the mitigation area for the site. 2.3 Construction Fencing & Erosion Control All erosion control measures adjacent to the mitigation area including silt fencing will be installed. Erosion control lcncing will remain around the mitigation area until clearing, grading and the construction area is stabilized. 2.4 Grading of Creation Area The creation area will be over excavated to an approximate depth of 6-9-inches below the specified grades and will be brought back to grade with native top soil. Only quality topsoil/organic materials are to be use for the wetland creation mitigation area. 2.5 Stabilization of Mitigation Areas All mitigation areas disturbed during plant installation will be stabilized per Section 3.4.2 with seed, mulch, or alternative method as approved by the City, and the permitting agencies upon completion of installation. Erosion control fences will be restored and placed around the mitigation area as specified on the mitigation plans. 2.6 Plant Material Installation All plant material will be planted by hand per detail and Construction and Planting Notes. The Mitigation Plan specifies the required size, species, quantity, and location of plant materials to be installed. The Landscape Installer will re-seed or over-seed all mitigation areas disturbed during the planting process. Upon completion of the planting, the erosion control fencing will be restored and repaired. Plant substitulions or modifications to locations shall be approved in writing, by the Owner's biologist and the City prior to installation. 2.7 Permanent Fence and Critical Area Sign Installation Upon acceptance of the plant material installation by the project biologist, a permanent fence will be installed along the west and north property lines as shown on the Mitigation Plan and Critical Area signs will be placed on-posts or on the fence as shown on the Final Mitigation Plan. 2.8 Construction Inspection Upon completion of installation, the Owner's biologist will conduct an inspection to confirm proper implementation of the Mitigation Plan. Any corrections, substitutions or missing items will be identified in a "punch list". Items of particular importance will be soils in pits, pit size, plant species, plant size, mulch around pits, and tree staking. Upon completion of planting, if installation or materials vary significantly from the Mitigation Plan, the Landscape Installer will submit a reproducible "as-built" drawing to the Owner. 2.9 Agency Approval Following acceptance of the installation at both the project site and the mitigation site by the Owner's biologist, a letter will be prepared to the City and the permitting agencies requesting approval of the installation. 2.10 Monitoring Inspection and Reporting The moniloring program will begin in the first growing season (approximately one year) following installation approval by the City and the permitting agencies. The subsequent monitoring inspections will be conducted in accordance with the approved Monitoring Program. 2.11 Silt Fence Removal Erosion control fencing adjacent to the mitigation area will remain in place until the mitigation area has been slabilized. 2.12 Project Completion If, after lhe final year of monitoring, the project has satisfied the objeclives and goals of the approved Mitigation Plan, the Owner's biologist will prepare a letter to the City and the permitting agencies requesting final approval and closure of the mitigation plan. 3.0 CONSTRUCTION AND PLANTING NOTES 3.1 SITE PREPARATION 3.1.1 The Lw1dscape Installer will inform the Owner of any discrepancies between the approved construction document and existing conditions at the mitigation sites prior to initiation of any mitigation installation work. 3.1.2 The Owner will define the limits of the mitigation planting area with orange construction fencing at both sites. The Landscape Installer will be responsible for maintenance of this fencing until the installation has been accepted by the City, and other permitting agencies. The Owner will be responsible for ensuring that this fencing remains in place during the construction of the project and the mitigation areas on the site. The Owner will be responsible for ensuring that no natural features or vegetation (existing or planted) are disturbed in the protected critical areas, including the mitigation area, during construction of the project and its amenities. 3.1.3 The Landscape Installer will hand grub all weedy species including scotch broom, blackberry varieties, and thistles within the mitigation areas where grading will not occure prior to mitigation planting. Grubbing of weeds, including root-stock, will be completed without the use of chemicals. Weed debris will be disposed off site. 3.1.4 Grading Requirements: A person who clears, grades or othenwise disturbs a site shall provide erosion and sediment control that prevents, to the maximum extent practicable, the transport of sediment from the site to drainage facilities, water resources and adjacent properties. Erosion and sediment controls shall be applied as specified by the temporary erosion and sediment control measures and pertormance criteria and implementation requirements in the Surtace Water Design Manual. 3.1.5 Seasonal Limitations for Clearing and Grading: From October 1st through April 30th, which is the seasonal limitation period, clearing and grading shall only be permitted if shown to the satisfaction of the Director that runoff leaving the construction site will comply with the erosion and sediment control measures and performance criteria and implementation requirements in the Surtace Water Design Manual through a combination of the following: a. Site conditions including vegetative coverage, slope, soil type and proximity to receiving waters; and b. Proposed limitations on activities and the extent of disturbed areas; and c. Proposed erosion and sedimentation control measures. 3.2 PLANT AND HABITAT MATERIALS 3.2.1 All plant materials will be as specified in the plant schedule. Only vigorous plants free of defects, diseases and infestation are acceptable for installation. 3.2.2 All plant materials will conform to the standards and size requirements of ANSI Z60.1 "American Standard for Nursery Stock". All plant materials will be native to the northwest, and preferably the Puget Sound Region. Plant materials will be propagated from native stock; no cultivars or horticultural varieties will be allowed. All plant materials will be grown from nursery stock unless othenwise approved. 3.2.3 All nursery grown plant materials will be in containers or balled and burlapped. Bare root plantings will be subject to approval. 3.2.4 All plant materials stored on-site longer than two (2) weeks will be organized in rows and maintained by the Landscape Installer at no additional cost to the Owner. Plant materials temporarily stored will be subject to inspection and approval by the Owner's biologist prior to installation. 3.2.5 Substitution requests must be submitted in writing to the Owner and approved by the Owner's biologist and the City in writing prior to delivery to site. 3.2.6 All plant materials will be dug, packed, transported and handled with care to ensure protection from injury. All plant materials to be stored on site more than 24 hours will be heeled into topsoil or sawdust. Precautionary measures shall be taken to ensure plant materials do not dry out before planting. Buffer plants will be shaded and saturated until time of installation. Immediately after installation the mitigation planting area will be saturated to avoid capillary stress. 3.2.7 The Landscape Installer will verify all plant materials quantities shown on the planting plan and the plant schedule. 3.3 PLANT MATERIAL INSTALLATION 3.3.1 All plant materials must be inspected prior to installation to verify conformance of the materials with the plant schedule including size, quality and quantity. Any plant materials deemed unsatisfactory will be rejected. 3.3.2 All plant materials delivered and accepted should be planted immediately as depicted on the plan. Plant materials not planted within 24 hours will be heeled-in per note 3.2.6. Plant materials stored under temporary conditions will be the sole responsibility of the Landscape Installer. Plants will be protected at all times to prevent the root ball from drying out before, during, or after planting. 3.3.3 All planting pits will be circular with vertical sides and will be sized per detail on the mitigation plan. The pits will be filled with on-site amended native soils. 3.3.4 No fertilizers will be used within the wetland except as noted on the planting detail. In buffer areas only, install "Agriform", or equal plant fertilizer to all planting pits as specified by manufacturer. Fertilizers are allowed only below grade in the planting pits in the buffer areas. No sewage sludge fertilizer ("SteerCo" or "Growco") is allowed in the mitigation area. 3.3.5 All containerized plant materials will be removed from their containers carefully to prevent damage to the plant and its roots. Plants removed from their containers will be planted immediately. 3.3.6 All plant materials will be placed as shown on the approved mitigation plan. If the final installation varies from the approved mitigation plan, the Landscape Installer will provide the Owner with an "as-built" reproducible drawing of the installed conditions. 3.3.7 All conifer trees will be staked per the detail on the mitigation plan. All deciduous trees 1" caliper and larger will be staked per the detail on the mitigation plan. Tree staking and guy wires will be removed from all trees one year after installation. Cut guy wires away from trees and remove wire and tree stakes from site. 3.4 PLANTING SCHEDULE AND WARRANTY 3.4.1 A fall-winter installation schedule (October 1st -March 15th) is preferred for lower mortality rates of new plantings. If irrigation is required under Section 4.3 during the first year after plant installation, the plantings will be irrigated with a temporary automatic irrigation system throughout the summer months. The automatic irrigation system will provide head to head coverage of the entire planting area. The automatic controller will be scheduled for a minimum of fifteen (15) minutes every day until fall rains can provide adequate rainfall to support the plant material. The mitigation plantings will be watered twice a day for fifteen (15) minutes for the first week. This schedule may be modified if the City approves hand-watering for the project. 3.4.2 All buffer areas disturbed during installation will be mulched or seeded with mixes as specified on the plans as soon as the mitigation area grading is complete. If mulch stabilization is used, arborist mulch (or approved equivelent) should be placed at a minimum depth of 6 inches and must not tough the sems of installed vegetation. If seed stabilization is used, seeds must be germinated and a grass cover established by October 1st. If the cover is not adequately established by October 1st, exposed soils will be covered with approved erosion control material and the Landscape Installer will notify the Owner in writing of alternative soil stabilization method used. 3.4.3 The Landscape Installer will warrant all plant materials to remain healthy and alive for a period of one year after final acceptance. The Landscape Installer will replace all dead or unhealthy plant materials per the approved plans and specifications. 3.5 SITE CONDITIONS 3.5.1 The Landscape Installer will coordinate with the Owner and the Owner's biologist for construction scheduling. 3.5.2 The Owner will install silt fences as shown on the approved grading plans for both sites. The Landscape Installer is responsible for repair and replacement of silt fences disturbed during plant installation. No equipment or soils will be stored inside the silt fences or within the protected critical areas. 3.5.3 Orange construction fence will be placed around the mitigation areas as noted on the plans to prohibit equipment in tt1e mitigation area of the project site. As noted above all planting will be by hand. The Landscape Installer will be responsible for maintenance of the construction fencing during installation and will insure that the fence is fully repaired as part of the final installation review process. 3.5.4 Soils exposed during plant installation at the project site will be seeded or mulched by the Landscape Installer using the native seed mix noted on the Mitigation Plan. 3.5.5 Al! plant material will be planted with suitable soils per planting details. Soils from planting holes will be spread and smoothed across the mitigation area. 4.0 MAINTENANCE PROGRAM INTRODUCTION This maintenance program outlines the program, procedures and goals for mitigation of the wetland and buffer impacts at the mitigation site. Maintenance is required for the mitigation site according to this program. This maintenance program will be the responsibility of the project Owner two times per year throughout the duration of the monitoring period. The maintenance will be completed as outlined below. 4.1 MAINTENANCE WORK SCOPE 4.1.1 The primary goals of the mitigation plan are to create wetland and emhance buffer areas. To accomplish lhis goal, normal landscaping methods must be modified to include: a. No mowing or trimming of ground cover or vegetation in any parts of the protected critical areas except to control or eradicate invasive species, including blackberry, scotch broom, tansy ragwort, reed canary grass, etc. b. No placement of fertilizers in any parts of the protected critical areas in any parts of the protected critical arnas. c. Mo placement of bark mulch or equivalent in any parts of the protected critical areas except around the individual shrubs and trees as noted in the planting details or in areas of invasive species removal. d. No placement of grass clippings, landscape debris, fill or ornamental plant materials in any parts of the protected critical areas. 4.1.2 Work to be incll.tded in each site visit: a. Remove all litter including paper, plastic, bottles, construction debris, yard debris, etc. b. f!,,move all non-native, invasive and noxious vegetation including blackberry varieties, thistles, tansy ragwort, scotch broom, etc. Remove all vegetation, particularly reed canary grass, from the planting circle or inside the drip line of the plant, whichever is larger, adjacent to the installed shrubs and trees. All removal of vegetation is to be conducted by hand without the use of pesticides or chemicals. All debris is to be removed from site and disposed in an approved landfill. Refer to agency list of noxious weeds for further information. c. Repair silt and/or construction fencing as needed. d. Repair permanent fencing and signage as needed. 4.1.3 Work to be completed on an annual basis includes: a. Replace dead or failed plant materials. Replacement plantings are to be of same species, size and location as original plantings. Plantings are to be installed during the dormant period. b. Remove tree staking and guy wires from all trees after one year. 4.2 MAINTENANCE SCHEDULE The Owner will conduct all items listed in the Maintenance Work Scope two times per year. Additional work may be required per the Monitoring Report and as approved by the City. Additional work may include additional watering, removal of the volunteer vegetation, particularly reed canary grass, around each planted shrub and tree, installation of wood chips at each shrub and tree base, reseeding the mitigation area, re-slaking existing trees and erosion control protection. 4.3 \'/ATERING REQUIREMENTS 4.3.1 All plants in the mitigation area shall be watered during the first dry season (March through September) after installation. Hand-watering may be used during this first growing season if the plants are installed during the dormant season (March 15 and October 15. However, a temporary irrigation system will be required (in the buffer area only) if the plants are installed between March 15 and October 15 of the installation year. The temporary irrigation system may be removed after one year of monitoring at the approval of the permitting agencies providing the plantings are established and acclimated to on-site conditions per Conslruction and Plantings Notes Sec. 4.0. 4.3.2 Irrigation will continue from initiation through October 1st, or between June 1st and Oct. 1st for any subsequent year. Irrigation, if required, will provide head to head coverage for 15 minutes per day every dav. 4.3.3 Hand watering may be approved by the City and other permitting agencies if water is not available to the site. A watering schedule will be approved by the Owner's biologist and the City, and other permitting agencies prior to final acceptance of the installation. CLOSEOUT OF THE MONITORING PROGRAM 5.0 5.1 Upon completion of the monitoring program and acceptance of the buffer mitigation by the agencies, the maintenance of the project will be reduced to include removal of litter and debris, repair of perimeter fencing and signage, removal of noxious weeds and undesirable vegetation, and repair of vandalized areas. MONITORING PROGRAM SAMPLING METHODOLOGY The mitigation area will be monitored 8 times over a five-year period. Monitoring will be conductedquarterly the first year and annually thereafter. Monitoring will be conducted using the techniques and procedures described below to quantify the survival, relative health and growth of plant material as well as the successful enhancement of the buffer vegetation. A monitoring report shall be submitted following each scheduled monitoring visit which will describe and quantify the status of the mitigation at that time. Both vegetation and hydrology will be monitored during each monitoring year. 5.1.1 Vegetation All the planted material in the mitigation area will be inspected during each monitoring visit to determine the level of survival of the installation. The health and vigor of the plants and the overall condition of the mitigation areas will be noted. Healthy, vigorous plant material will be documented to determine both overall success of the plantings and individual species success. Vegetation monitoring will be completed during each site visit of each monitoring year and will be documented in the required monitoring reports. Additionally, peranent photo points will be estabolished to document vegetative reponse, and photos will be provided within the required monitoring reports. 5.1.2 Hydrology Hydrology will be monitored weekly from March through May throughout the monitoring period until which point it has been determined that wetland hydrolegy criteria have been met in accordance with the Army Corp of Engineers guidance. Wetland hydrology will be considered present if innundation or saturation to the surface is present for 12.5 percent of the growing season, or approximatly 31 consecutive days. Hydrology will be monitored by the instillation of hydrology monitoring wells. The locations of hydrology monitoring wells will be indicated on a map within the monitoring report. 5.2 STANDARDS OF SUCCESS 5.2.1 Standards of sucess for each of the Buffer Enhancement Area shall be as follows: a. Volunteer native, non-invasive species will be included as acceptable components of the mitigation succes and will count toward percent cover preformance standards. b. Success of the mitigation within the mitigation areas will be determined by Year 1: 100 o/o survival of all planted shrubs and trees Year 2: 80°/o survival of planted material Year 3: 80°/o survival of planted trees and 55 °/o aerial shrub coverage at the end of Year 3 Year 4: 80°/o cover of planted trees and 75 °/o aerial shrub coverage at the end of Year 4 Year 5: 80°/o survival of panted trees and 80°/o aerial shrub coverage at the end of Year 5 c. Not more than 10%, cover of non-native invasive species within mitigation area during any of the 5 years. 5.2.2 Standards of Success for the Wetland Creation Area shall be as follows: a. Volunteer native, non-invasive species will be included as acceptable components of the mitigation succes and will count toward percent cover preformance standards. b. Success of the mitigation within the mitigation areas will be determined by: Year 1: 100 % survival of all planted shrubs and trees, 50% ground cover of herbaceous vegetation Year 2: 80°/o survival of planted material and 60% or greater ground cover of herbaceous vegetation Year 3: 80°/o survival of planted trees and 55 °/o aerial shrub coverage at the end of Year 3 Year 4: 80% cover of planted trees and 75 % aerial shrub coverage at the end of Year 4 Year 5: 80% survival of panted trees and 80°/o aerial shrub coverage at the end of Year 5 c. Not more than 10%, cover of non-native invasive species within mitigation area during any of the 5 years. d. Successful hydrology will be determined by whether soil saturation or inundation occurs during the early growing season. Specifically, hydrology should meet the criteria as stated in the Department of Army Corp of Engineers delineation manual including the western regional supplement. 5.4 CONTINGENCY PLAN A contingency plan can be implemented if necessary. Contingency plans can include additional plant installation, erosion control, and plant substitutions including type, size, and location. If the monitoring results indicate that any of the performance standards are not being met, it may be necessary to implement all or part of the contingency plan. Careful attention to maintenance is essential to ensure that problems do not arise. Should any part of the site fail to meet the success criteria, a contingency plan will be developed and implemented with the City and permitting agencies' approval. Such plans are prepared on a case-by-case basis to reflect the failed mitigation characteristics. Specific conditions that could require development of a contingency plan may include but are not limited to: a. Failure of the mitigation project to meet the standards for plant survival identified in Section 5.2 Standards of Success. b. Failure of the mitigation project to meet wetland hydrology criteria within the wetland creation areas. Contingency/maintenance activities 1T1ay include, but are not limited to: a. Replacing all plants lost to vandalism or mortality at the end of the Year 1. b. Substituting any plant species with a 15 percent or greater mortality rate at the end Year 1 with a similar species approved by the City and the permitting agencies. Substituted plants will be installed in the same quantities and locations as shown on the approved Final Mitigation Plan. c. Temporary irrigation of the mitigation area may be required as necessary during dry weather if plants appear to be too dry during any site visit of the monitoring. Irrigation will be provided as noted in Section 4.3 Watering Requirements. d. Reseeding the enhanced stream and wetland buffer areas with an approved grass mixture as necessary if erosion/sedimentation occurs. e. Removing all trash or undesirable debris from the mitigation areas as required in Section 4.0 Maintenance Program. f. Removing invasive species from the mitigation areas as required in Section 4.0 Maintenance Program. Sevvall Wetland Consulting, Inc. 27641 Covington Woy SE #2, Covington. WA 98042 253-859-0515 Fax 253-852-4732 (fl z 0 (J) > w Cl'. <] <] <] <] Job No. A5-209 Designed by: ES Drawn by: TS Checked by: Date: OCT. 2011 SHEET W-3 OF W-3