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HomeMy WebLinkAboutReport 1 - 1 of 71. PROJECT OVERVIEW: Evendell is located between 1561 h A venue SE and 1601 " Avenue SE on the south side of the unimproved ROW of SE 136 1 h Street within Section 14, Township 23N, Range SE in King County, Washington. See attached vicinity map. The 13.8-acre property is currently occupied by two single-family residences with associated outbuildings. Existing ground cover consists of a combination of forest, pasture, lawn, and landscaping. A wetland is also located at the northeast comer of the site. A boundary line adjustment will be completed to except one existing residence located along 156 1 h Avenue SE. The second residence will be included within a proposed lot within the development. Proposed development of the property will include the demolition of all structures on the property except for the excepted residence and the house within proposed Lot 52 and construction of70 proposed single-family lots, 69 new and I existing residence lot, along with associated open space, roadway and utilities. Along with site improvements, an 8' wide shoulder will be added to 1601h Avenue SE and SE 1361h Street will be constructed through the existing unimproved ROW along the property's frontage. A drainage basin ridge runs through the property separating the onsite drainage into two drainage basins. On-site generated runoff will be directed to one of two detention/water quality facilities. A small amount of upstream area is tributary to the eastern portion of the site and will be routed through the detention/water quality facility. Level 2 Flow Control will be utilized for the East Basin along with downstream improvements. Level 3 Flow Control will be utilized for the West Basin. Both basins will be treating the drainage with Basic Water Quality Treatment. ) King County Department of Development and. Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ParU -.· PROJECT OWNER AND-. P8()JEQTJ:NGINEER · . . Project Owner SBI Developing, T.LC Address PO Box 73790, Puyallup, WA Phone 253-539-8116 Project Engineer David Cayton, P.E. Company Core Design, Inc. Part 2 . PROJECT LOCATION AND _DESCRIPTION_ Project Name Evendell Location Township --=2c.=3.=cN=---- Range SE ............. Section ___ 1_4 ___ ~ Address/Phone14711 NE 29th Pl, Se 101, Bellevue, WA 425-885-787 7 ··Part3 'TYPE·OF•PERMIT·. APf'LiCAtior'J . . .. x Subdivison Short Subdivision Grading Commercial Other ________ _ Partc4 .OTHER REVIEWS AND PERMITS DFW HPA Shoreline Management COE 404 (Rockery '\ DOE Dam Safety c'&ructural Vaults) FEMA Floodplain Other COE Wetlands Part 5. Sl"fE COMM\JNITY AND DRAINAGE BASIN Community Newc.astlQ Drainage Basin Lower .:Cedar River .-.... ,·. . . . . •,. Pait6'• SITE CHARACTERISTICS·.· •'., : .. ,,'1.",· .. '·_ .,.," '. ... '' ' : River Stream __________ _ Critical Stream Reach Depressions/Swales Lake ___________ ~ Steep Slopes--------- . Floodplain ________ _ Wetlands X Seeps/Springs High Groundwater Table Groundwater Recharge Other __________ _ Part,'7 SOIL:S . . . ... Soil Type Alderwood (AGC) Slopes 6-15% Additional Sheets Attached C Part 8 DEVELOPMENTLIMITATIONS REFERENCE Ch. 4 ·Downstream Analysis Additional Sheets Attached Part 9 . ESC REQUIREMENTS . MINIMUM ESC REQUIREMENTS DUAi G CONSTRUCTION Sedimentation Facilities Stabilized Construction Entrance Perimeter Runoff Control Clearing and Graing Restrictions Cover Practices Construction Sequence Other Erosion Potential Moderate Erosive Velcoties LIMITATION/SITE CONSTRAINT 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 t. ' 'Part 10 • SURFACEWATER SYSTEM _. ' .. Grass Lined Tank Infiltration Method of Analysis Channel ~ Depression SBUH (FipeSystem) Compensation/Mitigati Energy Dissapator Flow Dispersal on of Eliminated Site Open Channel Wetland Waiver Storage Dry Pond Stream Regional {wet Pond"') Detention Brief Description of System Operation Developed drainage collected in pipe /catchbasin system and treated in.detention/water quality Facility Related Site Limitations facilities on-site. Reference Facility Limitation Part'11 STRUCTURAL ANALYSIS (cast in Place Vault) Retaining Wall C§ockery> 4' Hig~ Structural on Steep Slope Other Part12 EASEMENTS/TRACTS rainage Easement Native Growth Protection Easement Ot er · Part 13 SIG.NATlJRE OF PROFESSIONAL ENGINEEF) I or a civil engineer under my supervision 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. ?(z..r(o Si ned/Data NE 4TH ST SE 128TH ST w U) w w U) w U) 'i' w > w i'= « 'i' <O i'= "' co i'= "' 0 <O · . .:'7:-_'IF_'' ·i' -~,,::! SE 137TH :J,~'~'·i·;., SE 38TH :;ij)j~ SE 139TH ST SE 141ST ST ;1,'<''v SE 142ND ST ,• c,<., SE 143RD ST ~" SE 144TH ST 169 VICINITY MAP 0 eoo •oo ~ f--M. P"'H;w,l@i!W<, SCAL£ IN F't£T ("l t'l !'H::, ("l "'l 0 -<: Z ::0 O :::: ::0 t'l "1 > -= ., t'l 2 ........ -< C: "= t:1 2 2 "'l ::0 ::0 t'l t'l > ::0 t,o, ot""gJ'°1o"' ._t"".,.i"l:,,O t'l Z>'"" ("l "1 2 t"" ~ --3 ~>t'l.., 2 00 r<---o t'l -< t'l • t'l Cl) t"" Cl) ....... t'l : t:I :i >< 0 .... ::i:: :;; 0>2 i: 0 ~ z O Cl) °' N --3 "'l O ~ 0 C: > ~ Cl) ~ 0 ~ U} \ \ ,. I r / i('. '' i' I I '. \ j ; el '•, '-... .. '\" -~-·v••·.:?;:c:;;,·,;,)'{:'{\f'''..:· ::(r::••:I U \ I) !.'( \ .J ( l , \ j ) I . Lil\ 1,5111 .1· J,.: ·--, .. i r;... V·\\i-1 ~,., ·~· Iii I\ I \ I !" ·1 ·, ,,, \} / , .. -. ~ ·-. ,,. ::·!1 1· .. r , '\ r. 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' / ,,,.,, ,. ., ,I_ :Jf ' 1 ..,1 :,_}"lr,>.~.r,,(.~,;_J~ i •. ,..~, '~·::~' \, ~ ~-~., f V '·-..,, .,, u i l $1'\ \ ~,. "··~ i ! :r, ii\ \ Ii-"' Jf : "\i p--, ,, ; \.. r i \ t· ·,·,,,. . .,.,._ ,~,_,, ... -....... , ,J ~-ti! t w ~ ~,/ "' . - \ [ ,,' '" ' 11· ... _ q ~ \i./" ·-n i:~., ............ , .. . "' ·1, n ',, ,, '\',: \L (-.,.,., ......... , ,"'""\";)<' ,. ,., C{H i;;"..-·· ,·,.--. tt"i-' Hf J '} :J ·-. .,.:~-... -.... .,.. .. .,. •-'''1.r' ' " 1 .. 1:-0. \h: ' }> J , ... , , ;: EVENDELL Jt. I I I:,• ff ir 1i ·}.·' '''.} :ii J ··. lf} \, .. .,"! '·' ,:: l \~ ,J:;f-~-~.:. ·, / .~" '· ,•" 'exeast' /(9,3 AC> /,,... / J_ ~.,.) C,;,1 '::~i·'-''-, .. ; t!' 156TH !' ·, •: AVE SE ,· ' ·.·', .. w7 wE3_ i' ·, I ,, ' ! ; I .. ;,, :,•., ,, ,, p,,, .. .:(•···· ' ·, \ \ l I \ ·".; I 1 ~ ~fr~ IS, 1}7, QF ;j .•TRPlllTARY 'ARJ::A ,, ''\ ''•,,,\;::::>((< \ SITE IS :5% OF TRIBUTARY AREA', ,., .' ... ...-- ' ·,~.-,··,y·· ;f· ··\ ,, '\ . --~~-.. ~-!~ ... ,~:·:·· .. ··-.,., I.',., !{ ·F" '. '· ' r ,i ~- e5 Q ~- f el ' ' I " ;;:, "i.. .. q}•;,'. . •. ' j"'i ~eL~bn Co of tn.1S. . ~ oY1'" '.-:Sbr A~ ... SITE IS 9% OF TRIBUTARY AREA PROJECT NO, Haozous Engineering CIVIL ENGll£ERJNG EVENDELL PLAT i......u.;....,..... 1"816 SE U6TH ST, RDITDN, VA 980,9 '42$-235-2707 .......... .. ,., £.jl,l 8/12/02 ....... .. ... FJM 8/12/02 ncuRE Drainage Basins 2 ·oN l~Jro~d .LV1d 113GN3A3 l0l2-S£2'-G2t 6i;;os& VA 'ND!~ '!$ H.l9n 3$ 9l8t>l DNnD3i!DNJ 11/\13 ~UJ.133UJ~U3 BilOZOllH 133.:f NI J"l'tJS b6¥++m;.*"'1 oo.. ooa • __ .. .. .. •• ' sFf AGRICULTURE KING COUNT-ON SERVICE (RENT ~..--......--,,,--~~~-~1-.680~.ooo~!~~ET~~~r-~--:-~;;;;;;;;..l.i::~~~c::::;::2!.,....~~~~~~--'~~"'1'11:!r-:~'--i""'F~'""""' ....... '-'=~--t-~- •• •,. ·····•· . .. ,. t·· . • •r. . . • • I : • ·--·--·-, ( .. •• . a • a • I , , , ., AaC -----.11:. . . • • I .:. .- .. . 1~,,A...~.~ . ...:.· :~ . ,' ,,•' ,,•' ,: ':i / l ' / . \ ,.,' t ••• '•: : ., •' I ••'•I •• • . . . . . ~ . .... . .. . : . . . . . : e I e • . --BM .. 574 . I I I I KING COUNTY SOIL SURVEY EVENDELL C ORE PROJECT NO. 04009 2. CONDITIONS AND REQUIREMENTS SUMMARY: Listed below are the Hearing Examiner's Conditions. The postmaster approval is included in Section 6 of this report. Attached at the end of this section is an email between Kurt Wilson ( developer) and Corey Thomas (City of Renton Fire) regarding the emergency access cable and/or chain gate option, a copy of the SWM Adjustment L02V0024, and a copy of the title report regarding drainage easement. The preliminary plat revision ofEvendell, as received October 1, 2003, is APPROVED, subject to the following conditions for final plat approval: I. Compliance with all platting provisions of Title 19 of the King County Code. To be address during final plat. 2. All persons having an ownership interest in the subject property shall sign on the face of the final plat a dedication which includes the language set forth in King County Council Motion No. 5952. To be address during final plat. 3. a. The plat shall comply with the maximum density (and minimum density) requirements of the R-4 zone classification. All lots shall meet the minimum dimensional requirements of the R-6 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 Environmental Services. To be address during final plat. b. The Applicant shall provide transfer of density credit documentation to DDES prior to final approval to allow transfer of a maximum of 20 density credits to achieve a maximum of 70 lots on the subject property. To be address during final plat. 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), subject to any variances that may be approved by the King County Road Engineer. Construction of the roads comply with KCRS. See sheet Cl.02 and C3.31 of the civil plan set for road sections and pavement design. 5. A Boundary Line Adjustment (BLA) shall be completed prior to final plat approval to except from the plat that portion of the 200 (approximate) feet on the far west that is not part of the proposed plat. Documentation demonstrating the resolution of boundary issues with the property to the south (Nichols Place) also shall be provided to DOES. To be address during final plat. 6. The Applicant must obtain the approval from 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. Joint Use Development Tract H as shown on the plat will provide access to Lots 28 and 29. Additionally, it is a future emergency vehicle access tract to and from 1601 h Avenue SE, which the Applicant proposes to create in response to concerns raised by the City of Renton. The Applicant shall include proposed protocols for the construction and maintenance of Tract H, plus any related plat notes, with its engineering plans submittal, meeting the following standards: The emergency vehicle access to 160th Avenue SE shall have a minimum driving surface width of 20 feet, with an all-weather surface capable of supporting 25 tons. Any locking device shall be approved by the Renton Fire Department (KCFD # 25). Chains, cable or bollards will not be permitted. The gate shall be located at least 50 feet from 160th Avenue SE to allow space for fire apparatus to stop while opening the gate or to wait before entering the public roadway. If these conditions are not met any future residence constructed on Lots 28 and 29 will have to be sprinklered NFPA l 3D. These requirements concerning adequate fire and emergency access may be modified in a manner approved by the King County Fire Protection Engineer and King County Fire District no. 25. Approval of the fire hydrant placement is attached on the following page. See sheet Cl. 02 of the civil plan set for Tract H road section. The Renton Fire Department is okay with a cable or chain within the emergency vehicle access per the attached email located at the end of this section. 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' '_ jj ' '-~ ' ' .. \! \ '. 1•,i, . x-----X-'\' X _ .... ·'·\_ Lx ---rx. -Y:. --•. -.,: -·' . ,, ·----'::,s., I' '-..___ __,/_~--~--·--STA. 9-1-64 J'RT 1-_____ ----:;----· _{ .. ··-(,:;.~~I\ i::;,:;,.. j 1""8"ztr 1EE (RJ--,-~ .J-8" G41E VAll6 (Fl.;dlJ} i' -:::' _ _, ca,ctLOO!N;/ _. ~a,nr -=/)IJ) ,/ I ~' ~ ,,.._,· a.ow <YF-ASS'r .c \.. --./ DESIGN ca.c fl.OCl(N; ~ 1-'71 I NE291h l'lac&~ 101 aea.-, w~ 98007 425.885.7877 ~ 425.885.7963 ENGINEERING • PLANNING· SURVEYING ~ -I I I I i i i i ""109C<OI 0 200 400 b .... 4§. * I \ . \ r / u \ .f \ \ ·-ri :< I, "! I ' (,",.,··,· el ,/ w2 ,/· / ., . ' c::::.·l \ \ ) ,,.-. \ ,\ ,,,, wl ' ·156TH AVE r \ ·. : .. w? a:. a, In -' ,,, .. .., ···~)(.·-........ ~ r•--..··),l-::-;:~-·--·-,,..,, C , , ,.., .1 . .\ '· ·,I ''"'·~·-·····}---~.-·'"·'""• "'') J =: "exe·~st" /C:9.3 AC) / / I \.·,,~1 ,,...,.J~._~ , ~ t .. .,. .. / ... Y. ··SITE JS 5% OF TRI BUT f\RY AREA'. :.1 Haozous Engineering CIVIL ENGINDUNG 141116 SE 116TH ST, RENTON, VA 980~9 '425-235-2707 -·· .. ,.. 8/12/02 ....... .. ... £.IM B/12/02 r e7 ~ \ \ 1;- . .:. 1,. '·r"-. ; ., \ ! ·-/·· ··· .. i.· i)' '·-,., •.. ,.._ ~--~, . r .. ·,.·,' • SITE IS 9% OF TRIBUTARY A.REA PROJECT NO. EVENDELL PLAT FlGURE Drainage Basins 2 7. 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 location of lots 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 KCC 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 1998 King County Surface Water Design Manual and applicable updates adopted by King County. DOES approval of the drainage and roadway plans is required prior to any construction. Drainage facilities and analysis comply with the 1998 KCSWDM. See sheets C4.0l, C4.21, C4.22, C4.31, C4.32, C4.33 o the civil plan set for storm drainage design and T.J.R. for storm drainage analysis. b. Current standard plan notes and ESC notes, as established by ODES Engineering Review, shall be shown on the engineering plans. Plan notes are no sheets Cl.02, C2.0J, CJ.31, and C4.33 of the civil plan set. c. The following note shall be shown on the final recorded plat: "All building downspouts, footing drains, and drains from all impervious surfaces such as patios and driveways shall be connected to the permanent storm drain outlet as shown on the approved construction drawings# on file with ODES and/or the King County Department of Transportation. This plan shall be submitted with the application of any building permit. All connections of the drains must be constructed and approved prior to the final building inspection approval. For those lots that are desi!,'11ated for individual lot infiltration systems, the systems shall be constructed at the time of the building permit and shall comply with plans on file." To be address during final plat. d. The stormwater detention design shall comply with the Level 2 or Level 3 Flow Control requirements, as applicable, per the 1998 King County Surface Water Design Manual (KCSWDM). (See SEPA conditions in condition no. 19.) The West Basin drainage facility was sized using Level 3 Flow Control. The East Basin drainage facility was sized using Level 2 Flow Control. See T.IR. for detention analysis. e. The storm water control facility shall be located in a separate tract and dedicated to King County unless portions of the drainage tract are used for required recreation space in accordance with KCC 21A.14.180. The wetvaultfor the West Basin is located in a separate tract labeled "Tract N". The wetpondfor the East Basin is located in a separate tract labeled "Tract M". These tracts will be dedicated to King County during final plat. 8. Drainage adjustment L02V0024 is approved for this project. All conditions of approval for this adjustment shall be met upon submittal of the engineering plans. All conditions required for the adjustment have been addressed. See the end of this section for a copy of the adjustment. See T.I.R. for detention sizing which includes limiting release rates to existing conditions plus the addition of a 10% factor of safety. See TJ.R.for calculation of water quality volumes which includes the site improvements along with frontage improvements that are captured by the proposed drainage system. The two drainage tracts will be dedicated to King County during final plat. SEP A conditions have been addressed per Hearing Examiner's Condition I 9. 9. A drainage easement for the conveyance from the Tract N drainage facility to 156'h Ave SE shall be provided upon engineering plan submittal. The drainage easement is attached within the title report for the property. See the end of this section for the title report. 10. The following road improvements are required to be constructed according to the 1993 King County Road Standards (KCRS): a. The internal access road from SE J 36'h Street to the beginning of the internal loop road shall be improved to the urban subcollector standard, except that portion on the west side between Lot 11 and Lot 12 is not required to be improved with a sidewalk. See sheet CJ.02 of the civil plan set for the 158'' Ave. SE and Portion of SE 137'' St. section and sheets C4.21 and C4.22 for road centerline profiles. b. The internal loop road shall be improved to the urban subaccess road standard with sidewalks on the outside frontage of the loop road. See sheet Cl.02 of the civil plan set for the Portion of SE I 37'' St., 159'' Pl. SE, SE 138'' St., I 58'' Pl. SE section and sheet C4.21 for road centerline profile. c. SE 136"' Street (frontage and offsite) shall be dedicated, designed and improved in general conformance with the Preliminary Road Improvement Plan received 3/26/2002 with the Plat ofEvendell: The frontage from 158"' Ave NE to 1601h Ave NE shall be improved to the urban one-half street standard. Eighteen feet of additional right-of way shall be dedicated for this improvement. See sheet Cl.02 of the civil plan set for the SE I 36'' St (Between 158'' Ave. SE and ]6(!' Ave. SE) section and sheet C4.21 for road centerline profile. SE 136'h Street frontage from the west side of J.U.D.T. 'A' boundary to 158'h Ave NE shall be improved to the urban neighborhood collector standard; EXCEPT that no sidewalk construction is required on the north side. Twenty feet of additional right-of-way shall be dedicated for this improvement. See sheet Cl.02 of the civil plan set for the SE 1361 • St (Between 1561 • Ave. SE and 158'' Ave. SE) section and sheet C4.2 l for road centerline profile. SE 1361h Street from 156th Ave SE to J.U.D.T. 'A' shall be improved to the urban neighborhood collector standard; EXCEPT that no sidewalk construction is required on the north side. Twenty-six feet of additional right-of-way shall be provided for this improvement. An additional 25-foot right-of-way radius is required at the southeast comer of 156'h Ave SE and SE 136th Street. Striping for a second westbound lane shall be provided within the 150-foot widened section approaching 156th Avenue SE, in a manner to be worked out at the time of submission of engineering plans. See sheet Cl.02 of the civil plan set for the SE 1361 • St (Between 156'' Ave. SE and 158'' Ave. SE) section and sheet C4.21 for road centerline profile. See sheet C3.32 for striping of SE 1361 ' Street. d. 160th Ave SE FRONTAGE: The 160th Ave SE frontage shall be improved with an 8- foot paved shoulder on the west side. Adequate provisions for road drainage shall be provided. See sheets C3.01 and C3.3 l for shoulder construction information and pavement section. Drainage will be conveyed either to the bypass ditch along 16(/h or to the proposed drainage system. e. Tracts A,C,F,G,H, and I shall be improved to the joint use driyeway standard per Section 3.01 of the KCRS. Tract A shall include an easement to King County for the maintenance of the Tract N drainage facility. Tract A shall be owned and maintained by the owners of Lots I and 2. See sheet Cl.02 of the civil plan set for the Tracts A, C, F, H, & I section. Ownership and maintenance of tracts will be dedicated during final plat. f. Tracts B, D and E shall be improved to the private access tract standard per Section 2.09 of the KCRS. See sheet Cl.02 of the civil plan set for the Tracts B, D, & E section and sheet C4.22 for road centerline profiles. g. The Applicant shall revise the channelization that has been constructed in conjunction with the plat of Highland Estates (LOOP0009). These modifications to the channelization shall incorporate a revision of the current proposed painted 'island' to a southbound left tum lane with at least 60 feet of storage for left turning vehicles to (a) encourage the use of 156th Avenue SE in lieu of 158th Avenue SE and 160th Avenue SE, and (b) mitigate the potential deficient condition that would result from southbound left turning vehicles making left turns from the southbound through lane, or using the painted island as a deceleration and refuge area while waiting for gaps in northbound traffic. Channelization and illumination plans must be submitted to King County Traffic Engineering Section for review and approval of the tum lane channelization. Modifications to the above road conditions may be considered according to the variance provisions in Section 1.08 of the KCRS. See sheet CJ.32 of the civil plan set for the revised channelization and modification of the existing street lighting along 156'' Ave. SE. 11. There shall be no direct vehicular access to or from 160"' Avenue SE from those lots which abut this street. A note to this effect shall appear on the engineering plans and final plat. To be addressed during final plat. See sheet Cl.OJ on the civil plan set for a duplicate of the above condition listed under "Hearing Examiner's Conditions". 12. All utilities within proposed rights-of-way must be included within a franchise approved by the King County Council prior to final plat recording. To be addressed during final plat. 13. 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: (1) pay the MPS fee at 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. To be addressed during final plat. 14. The proposed subdivision shall comply with the Sensitive Areas Code as outlined in KCC 21A.24. Preliminary plat review has identified the following specific requirements that apply to this project. All other applicable requirements from KCC 21A.24 shall also be addressed by the Applicant. a. This site contains a Class 2 wetland. The majority of the wetland will be protected from alteration during and after construction, with a 50-foot wide buffer around the wetland boundary. An additional 15-foot building setback is required beyond the edge of the buffer. See sheets C3.0J and C4.0l of the civil plan set for delineation of 50' wetland buffer and 15' BSBL. b. A maximum of 200 square feet of wetland will be filled for construction of SE 136th Street. Mitigation shall consist of at least 400 square feet of wetland enhancement to degraded portions of the existing wetland. Wetland Mitigation plans are currently under review. c. Road improvements for SE 136th Street and 160th Avenue SE will eliminate 6,989 square feet of wetland buffer. Mitigation shall consist of providing replacement buffer in the northeast portion of the site at approximately a 2: I ratio to provide additional protection for the wetland pursuant to KCC 21A.24.320B. Reduced impact will result in reduced mitigation. Wetland Mitigation plans are currently under review d. The proposed sewer main within the SE 136th Street right-of-way will intrude into the wetland buffer along with the road improvements. In order to protect wetland hydrology: (I) the sewer line shall be installed during the dry season (June through September), and (2) the design shall incorporate the use of pipe bed dams of bentonite or other material at intervals to preclude draining possible subsurface water flows through the gravel pipe bedding. Design of the proposed sewer force main adjacent to the wetland along SE 136'' Street has been designed with the required note and design of pipe bed dams adjacent lo the wetland buffer. See Sanitary Sewer Plan set that will be approved through the City of Renton. e. Downstream drainage improvements to existing culverts and stormwater conveyances required through the SEPA MDNS shall cause no adverse alteration to existing wetlands or streams in the vicinity of the drainage improvements. Noted. f. Critical Areas staff shall review engineering plans for the plat and sewer main for conformance with these requirements. Noted. 15. The following note shall be shown on the final engineering plan and recorded plat: RESTRJCTIONS FOR SENSITIVE AREA TRACTS AND SENSITIVE AREAS AND BUFFERS Dedication of a sensitive area tract/sensitive area and buffer conveys to the public a beneficial interest in the land within the tract/sensitive area and buffer. This interest includes the 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 sensitive area tract/sensitive area and buffer imposes upon all present and future owners and occupiers of the land subject to the tract/sensitive 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/sensitive area and buffer. The vegetation within the tract/sensitive 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/sensitive 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 sensitive area tract/sensitive 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 IS-foot building setback line, unless otherwise provided by law. To be addressed during final plat. See sheet CJ.Of on the civil plan set for a duplicate of the above condition listed under "Hearing Examiner's Conditions". 16. Suitable recreation space shall be provided consistent with the requirements KCC 2 IA.14.180 and KCC 2 IA.14.190 in providing sport court[ s), children's play equipment, picnic table[s), benches, etc. a. A detailed recreation space plan (i.e., 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 the engineering plans. This plan shall comply with Ordinance # 14045. See sheets C7. 0 I and C7. 02 of the civil plan set for the Recreational Park Plan. b. A performance bond for recreation space improvements shall be posted prior to recording of the plat. To be addressed during final plat. ) 17. A homeowners' association or other workable organization shall be established to the satisfaction of ODES which provides for the ownership and continued maintenance of the recreation, open space and/or sensitive area tract(s). To be addressed during final plat. 18. Street trees shall be included in the design of all road improvements, and shall comply with Section 5.03 of the KCRS and KCC 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. See sheet C7.03 of the civil plan set for the Street Tree Planting Notes. 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. See sheet C7.03 of the civil plan set for the Street Tree Planting Notes. 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. See sheet C7.03 of the civil plan set for the Street Tree Planting Notes. 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. See sheet C7. 03 of the civil plan set for the Street Tree Planting Notes. Ownership and maintenance shall be addressed during final plat. e. The species of trees shall be approved by DOES if located 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. See sheet C7.03 of the civil plan set for the Street Tree Planting Notes. f. The Applicant shall submit a street tree plan and bond quantity sheet for review and approval by DOES prior to engineering plan approval. See sheet C7.03 of the civil plan set for the Street Tree Planting Plan along with tree count quantities. ) g. 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 of recording 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 DDES has completed a second inspection and determined that the trees have been kept healthy and thriving. A landscape inspection fee shall also be submitted prior to plat recording. The inspection fee is subject to change based on current County fees. To be addressed during final plat. 19. 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. East Drainage Basin: The 160th Ave SE downstream conveyance system shall be upgraded to provide for the 100-year storm capacity. Downstream driveway culverts/ditches and a cross- culvert under 160th Avenue SE shall be improved as follows: Culverts P-117 and P- 116 on the west side of 160'" Avenue SE, cross-culvert P-115, and culverts P-114 and P-113 on the east side of 160"' Avenue SE shall be improved as needed. The culvert designations are according to the Level 3 Downstream Drainage Analysis by Haozous Engineering dated August 26, 2002. To address a related localized flooding condition, bank and channel stabilization are also required in the unopened right-of-way for 162nd A venue SE, in the vicinity of the easterly line of Lot 12, Rich Lea Crest (address 16046 SE 142nd Street). It is estimated that stabilizing and re- grading approximately 50 to I 00 feet of channel, east of 16046 SE 142nd Street, will be adequate to resolve flooding that has occurred in the past location. The culverts and channel described are located from the south site boundary to a distance of approximately 1,700 feet downstream. Level 2 Flow Control design is required for the proposed stormwater detention facility. A factor of safety of 5 to 15 percent, determined by the design engineer, shall be required for detention storage volumes. Level 2 Flow Control was utilized for sizing of the East Basin we/pond. A 10%factor of safety was added per the minimum required as a condition of the Drainage adjustment L02V0024. Culverts Pl 15, Pl 14, and Pl 13 have already been replaced by others. Pl 15 is now a 24" N-12 and Pl 14 and Pl 13 are both 30" N-12. Culvert Pl 16 and Pl 17 will be replaced as part of this development. b. West Drainage Basin: The stonnwater detention facilities shall be designed to the Level 3 Flow Control Standard as described in the 1998 King County Surface Water Design Manual (KCSWDM). As an option, Level 2 Flow Control with downstream improvements can be proposed according to Core Requirement 2 of the KCSWDM. The minimum Flow Control Standard shall be Level 2. A factor of safety of 5 to 15 percent, detennined by the design engineer, shall be required for detention storage volumes. The downstream impacts of the I, 700 feet of conveyance improvements shall be reviewed by the developer's engineer, and any recommendations necessary to prevent flooding or other damage from occurring as a consequence of the required conveyance improvements shall be included with the plans for review by ODES. Level 3 Flow Control was utilized for sizing of the West Basin wetvault. A 10% factor of safety was added per the minimum required as a condition of the Drainage adjustment L02V0024. School Mitigation Fees 20. Lots within this subdivision east of 158th Avenue SE are subject to King County Code 21 A.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 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 pennit issuance. To be addressed during final plat. School Walkways 21. A pedestrian access easement between 158th Place SE and 160th Avenue SE shall be provided over either Tract H or L (as shown in Exhibit 62). The easement shall have a minimum I 0-foot width and be improved with a 5-foot wide paved surface. A pedestrian access easement will be provided through Tract L & H. See sheet C7.0J for location. 22. The Applicant, individually or in conjunction with other developers, shall construct an off-site walkway to Liberty High school from the site. The walkway shall be constructed within the right-of-way from 160th Ave SE, east along SE 135th Street to I 66th Ave SE, and south to Liberty High School at SE 136th Street, or via alternative right-of-way and easements that become available and are approved by DDES. One acceptable alternative would be to use future right-of-way of Southeast 136th Street and 162nd Avenue Southeast to connect with the sidewalk improvement of"five Jot subdivision," and through the plat of"five lot subdivision"/LOOP0023 to the southwest gate of Liberty High School. The walkway shall be designed and constructed in accordance with the 1993 King County Road Standards and shown on the engineering plans for DDES review and approval. Any surfacing alternative from the King County Road Standards (KCRS 3.09) may be submitted for approval through a road variance application. Off-site walkway is currently being constructed by others. (® King County Department of Development and Environmental Services 900 Oakesdale Avenue SW Renton, WA 98055-1219 October 17, 2002 Mike Romano Centurion Development Services 22617 Eighth Drive SE Bothell, WA 98021 Edward J. McCarthy, P.E. Haozous Engineering, P.S. 14816 SE 1161h Street Renton, WA 98059 RE: Evendell Subdivision SWM Adjustment Request (File No. L02V0024) Dear Applicant and Engineer: The Land Use Services Division, Engineering Review Section, has completed review of the adjustment request for the Evendell subdivision. You are requesting approval for an adjustment from the 1998 King County Surface Water Design Manual (KCSWDM) Core Requirement No. I, Section 1.2.1, Discharge at the Natural Location. Our review of the information and a site visit provides the following findings: 1. The prorosed Evendell subdivision is located west of 1601h Avenue SE and south of SE 1361 Street. The 75 lot, 11.7 acre, proposed E~dell subdivision is filed under Land Use Services Division (LUSD) file number l!P0016. 2. The Evendell subdivision is located in the Orting Hills subbasin of the Lower Cedar River basin. The site is subject to the Level Two flow control and Basic water quality requirements of the 1998 KCSWDM. 3. The site consists of two adjoining, rectangular areas south of SE 136th Street split by l 58'h Avenue SE. The smaller, western rectangle is 1.9 acres in size, while the larger, eastern rectangle is 9.8 acres. A common ridgeline passes approximately north- northwest to south-southeast through the two areas with the majority of the site draining to the east. The western subbasin sheetflows in a southwest direction through large, sin?le family rarcels and is eventually intercepted by a ditch dr~inage system on the east side of 156' A venue SE and flows south. The eastern subbasm sheetflows to the southeast and is eventually intercepted by a ditch system on the west side of 1601h A venue SE and flows south. Both downstream drainage· paths eventually recombine in an unclassified tributary of the Lower Cedar River. Most upstream flow is intercepted by ditches on the north side of SE 136'h Street and is bypassed around the project site or through the wetland area in the northeast comer of the site. • z •, 0 u ~ l : o, • z ; • ~ ,ii· " ~ N g ~, " N 0 i ... 0 ·• -~ N . i . .. E ;;; ~ C ,, ., \' Rebar & Cop LS 69634 J" tund ~ ,-< I Pl ~---- SE 138JH WAIEB QI W OX YAlft:l 10'W X 30"1. X 6.5'0 (INSIDE DIM.) 10P or VNJLT• 482.5 WATER SURF'ACEt: 482.0 . k BOT. OEr.• 4n.o N88dlA'381/ !300 • VOL• t,500 CF --~~§9}t}}J.~t. 1_3~t~ $~~~-~CF~· . ---)··· ... ... -·· =:_r.),_ ·_-:-·-.,. I ~ I9,AC \\ ""\ :7--. \ '"" ' ()~ ' I 0.58 AC DIVERTED ...1 ',. \.. J___ FROM EAST TO WEST ~ I i-__ _..,,t.---71 .,..c\~ 56 ) 75 j 1(i 73 I < I , '\ I-- ~ I _J L r-11 ·~-1 -J I I _J_ _J _J 0.73 J DIVERTED FROM WEST TO EAST Lot 7 Rbse " ~ ~ I I/. --/.-. r--· . ' ./ - • I - 1--~ 58 ! ~· I 11 .-.L-TE. r~- /--· -·' ·Ae-r . -. I . 6_1/ 60 i 69 y 68 ~: l/~--_"J-~t-1-__Y 63 I 64 j 65 ,{ 66 :i_ I' 0 ~ \ ~== I I ~ .~CO ~ s I~% IL >= ~j ; P.i IL dD ~ g:;z 0 ::, ;2 %~ 8 2£1 "' a::O ~ 0 t; U2 s s • It) ~ ~ s s : bl! Ot 6 -· i:::t I it ~ •""4 --ti~~ ~ ~ a, mi;j:ii ~ A ;;,; 5 ~,~ti::...e.J )~ti" I f.:l ~8~ ( ; 0 ~ 3 Ii 0 ,. N ., 0 ~ ., ..., ::r: § i/'112 ~ ~-0 2 !~ V ' =-=•~t'.VYl')f ' lllil I tar \../ I, I . I ~ ~. o- • Evendell/L02V0024 October 1 7, 2002 Page 2 of3 4. The proposal is to collect most rurioff from the project site and direct it to two facilities designed to separately accommodate drainage from the western and.eastern areas of the site. The result is that 0.58 acres of the eastern subbasin will be diverted to the flow control vault and bioswale of the western rectangle of the site; and 0.73 acres of the western sub basin will be diverted to the combined wetpond/detention pond serving the eastern rectangle of the site. In the developed condition, the net effect is that 0.15 acres of the western subbasin will become tributary to the eastern subbasin's downstream drainage system. As a result, controlled outflows from the western area will be released farther upstream in the ditch system of 1561 h Avenue SE reducing nuisance sheetflow through the intervening parcels. The release location from the eastern subbasin will remain the same. A negligible shift in flows in the two downstream drainage paths will result. The current conceptual drainage plan indicates that a significant amount of frontage improvement drainage will bypass the planned RID facilities. 5. No decorative ponds or shallow wells have been identified that would be affected by the proposed diversion. 6. The Level One and Three Downstream Drainage Analyses identified conveyance restrictions and nuisance flooding problems associated with both of the proposed downstream discharge locations. Although this adjustment is not addressing the potential for increased flow control standards as a result of the downstream drainage problems, the net impact of the proposed diversion will have a negligible impact on either downstream drainage path. Based on these findings, we hereby approve this adjustment to allow the diversion of on-site runoff between the two drainage subbasins to two separate facilities ultimately draining to their natural discharge locations with the following conditions: 1. The release rates for the detention facilities will be based on the natural and diverted tributary areas being directed to the facilities. 2. The volume for the detention facility will be based 'on all flows directed to the facilities at full development under current zoning. The allowed release rates will be reduced by any undetained flows that would bypass the proposed subdivision drainage facilities. A 10 to 20 percent volumetric factor of safety must be applied to all storm events requiring detention. The design Technical Information Report shall state the factor of safety selected and the basis of that determination. 3 .. Water quality facilities must be sized based on the entire proposed subdivision draining to the facilities including any required frontage improvements. 4. All onsite or offsite drainage facilities must be located in a public right-of-way or storm drainage tract dedicated to King County. Evendell/L02V0024 October 17, 2002 Page 3 of3 5. Additional storm drainage requirements identified by SEPA or the plat hearing review wUI apply to this project. · If you have any further questions regarding this KCSWDM adjustment or the design requirements, please contact Mark Bergam at (206) 296-7270. Sincerely, James Sanders, P.E. Development Engineer Engineering Review Section Land Use Services Division Jim Chan, P.E. Supervising Engineer Site Engineering and Planning Section Building Services Division cc: Curt Crawford, P.E., Managing Engineer, Stormwater Services, KCDNR Randall Parsons, P.E., Senior Engineer, Engineering Review Section, LUSD Bruce Whittaker, Senior Engineer, Engineering Review Section, LUSD Karen Scharer, Planner II, Current Planning Section, LUSD Mark Bergam, P.E., Senior Engineer, Engineering Review Section, LUSD King County Department of Development And Environmental Services 900 Oakesdale Avenue SW Renton, WA 98055·1219 Project Name: Evendell Plat Project Address: Portions of Sections 25 36 ofT23N RSE Appficant: Mr. Mike Romano Centurion Dev'elopment Services 22617 8th Drive SE Bothell WA 98021 Phone: ( 425) 486-2563. Date: ~~!oz_ ODES File No. DOES Engineer/Planned Name: LOIP0016 Bruce Whittaker, PE. Design Engineer (submitting variance): Phone: Edward J. McCarth P.E. 425 235-2707 Signature: tJward »· ftlc(qrt~ Engineering Firm Name: Haozous Engineering, P.S. Address: 14816 S.E. 116th Street Renton, WA 98059 Date: 2/25/02 DESCRIPTION OF THE VARIANCE REQUEST: !_Standard Request We request that the design of the stormwater facility that manages stormwater from developed portions ofEvendell be allowed to divert drainage from a net area of 0.15 acre from the west basin to the east basin on the site. APPLICABLE SECTION($) OF STANDARDS: The adjustment request is applicable to Core Requirement# I: Discharge at the Natural Location, Section 1.2.1 of the Surface Water Design Manual (King County Department ofNatural Resources, 1998). . ~p JUSTIFICATION (see --page attachment): . AUTHORIZED SIONA TURES: DDES Dlrector/Deslgnee Determination: _ Approval ~ ODES Approval Signed: CONDITIONS OF APPROVAL: t'J See attached memo dated: Jt>Jrt{o'1-- _Denial Date: l-0/rtf fr'?.--1 DOES, land Use Services Division, Engineering Revie'w Supervisor: DOES, Bldg. Serv. Div., Site Engineering & Planning Supervisor: Date: MAR2}~o~@ K.C. D.D.E.S .. King County Department of Development And Environmental Services 900 Oakesdale A venue SW Renton, WA 98055-1219 Even dell -Diversion of Drainage -Adjustment Request JUSTIFICATION: Description of Site The Evendell Plat project is a proposed residential development located within the Renton Highlands area of unincorporated King County. The proposal for development includes buildin~ 75 single-family dwellings on approximately 12 acres. Road improvements along SE 136 Street are also proposed. · . The site is located within the Orting Hills subbasin of the Cedar River watershed (King County Department ofNatural Resources, 1999). The site and area of offsite improvements consist of two basins. The east basin consists of 9. 84 acres under existing conditions. The topography of the east basin generally slopes from the northwest to the southeast. The west basin consists of 1.92 acres under existing conditions. The topography of the west basin generally slopes from the east to the west. The southwest comer of the site has an area of 0. 73 acre that is included in the westerly subbasin. Runoff from this subbasin sheet flows to adjacent yards of single-family residences to the southwest. Stormwater Design Under developed conditions, stormwater from the site and offsite road improvements will be collected and treated onsite to basic water quality standards. A combined wetpond/detention pond will be used to manage runoff in the easterly basin. A vault followed by a biofiltration swale will be used to manage runoff in the westerly basin. Level 2 RID standards are required by the King County Flow Application Maps and are recommended by Lower Cedar River Basin and Nonpoint Action Plan. Under developed conditions, the 0. 73-acre area in the southwest comer of the site will be diverted from the westerly basin and collected in the onsite stormwater system in the easterly basin. To compensate for this diversion of drainage, an area of 0.58 acre in the northwest portion of the site will be diverted from the east basin to the west. The net result will be a diversion of0.15 acre from the west basin to the east basin. Managing runoff with the proposed diversions results in the following features: • Two stormwater facilities will be constructed. A larger combined wetpond/detention pond will manage runoff in the easterly basin and will discharge to the ditch system along 160th Avenue SE. A vault will be used ?. to manage runoff from the smaller westerly basin and will discharge to the ditch system along 156th Avenue SE. 0 The discharge locations from each basin will be to an engineered conveyance system. a The net diversion of0.15 acre is not anticipated to cause any problems in either of the two basins. References King County Department of Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio. King County Environmental Division, 1990. Wetlands Inventory Notebook Volume 2 East. King County Department of Natural Resources, 1998. Surface Water Design Manual. King County Surface Water Management Division, 1993a. Cedar River Current and Future Conditions Report. CORE -Dave Cayton om: ;;;ent: Jo·: Subject: Kurt Wilson [kurt@soundbuilthomes.com] Thursday, April 29, 2004 2:48 PM CORE -Dave Cayton FW: Evendell Fire Access Requirement (Tract H) FYI-please work this out with KC fire for approval. Lets propose the cable or chain for now. Kurt Wilson SBI Developing, LLC Office: (253) 539-8116 Fax: (253) 539-0514 cell: (253) 377-7147 . c;c·;--:.·:·· _:::_''.{ir1ginal Message----- Ff6'ffl: Corey W Thomas [mailto:CThomas@ci.renton.wa.us] 'Hd1L • Seµt: Thursday, Apnl 29, 2004 11:38 AM f o: Kurt Wilson Subject: Re: Evendell Fire Access Requirement (Tract H) 1e Renton Fire Department will accept chain or cable type gating systems as long as the posts supporting them are fully clear of the 20°feet width when the chain or cable is unlocked. We will not accept boilards. The distance of SO-feet may be measured from the drive Jane ratµer than the right of way. >::;,> "Kurt Wilson" <kurt@soundbuilthomes.com> 04/28/2004 11 :55:27 >>> P~r condition# 6 we are required to provide a Jocking device which can .·;: ._11 • i,ofb~ a cable or chain, per our discussion you would allow this so Jong , I , • • @;Wt'.11.id not propose bollards. Can you affirm this in a response back t~1:ili~?i/lso, is there any possibility in locating the cable 50ft from tlje'tlnvmg lane on 160th rather than 50ft from the ROW? It would r,~~ilyhelp our access to the lot closest to 160th.: 6. The Applicant must obtain the approval from 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 K,:.ing County Code. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> ·· •irit Use Development Tract H as shown on the plat will provide access .,{[9ts 28 and 29. Additionally, it is a future emergency vehicle a'c~e~s(ract to and from 160th Avenue SE, which the Applicant proposes ~?t<!J'.1~tfin response to concerns raised by the City of Renton. The Acppl,1cant shall include proposed protocols for the construction and !)t>c:·:~ · 1 :maintenance.of Tract H, plus any related plat notes, with its : engineering plans submittal, meeting the following standards: The emergency vehicle access to 160th Avenue SE shall have a minimum driving surface width of20 feet, with an all-weather surface capable of .supporting 25 tons. Any locking device shall be approved by the Renton 1.,·, ' :{W~ Department (KCFD # 25). Chains, cable or bollards will not be 'p~tj:pi(ted. The gate shall be located at least 50 feet from 160th Avenue ;'$~)9}1.!low space for fire apparatus to stop while opening the gate or ".fc(~Ji(before entering the public roadway. If these conditions are not · ri1et>'any future residence constructed on Lots 28 and 29 will have to be sprinklered NFPA !3D. These requirements concerning adequate fire and emergency access may be modified in a manner approved by the King County Fire Protection Engineer and King County Fire District no. 25. Thanks for your consideration> I<":urt Wilson · "'iii P~veloping Jis~~-8116 office :2'53:5~9-0514 fax tsf3J7-7147 cell r,1 :-" ' . . This message has been scanned by the City ofRenton's filtering gateway. 2 CHICAGO TITLE INSURANCE COMPANY 701 F!FfH AVENUE, #3400, SEATTLE, WA 98104 A.L.T.A. COMMITMENT SCHEDULE A Title Unit: U-06 Phone: (206)628-5610 Fax: (206)628-9717 THIRD COMMITMENT Order No.: 1077234 Officer: SA VIDIS/WAGNER/CAMPBELL/MINOR Your No.: US LAND/SB! DEVELOPING Commitment Effective Date: MAY 5, 2004 1 . Policy or Policies to be issued: at 8:00 A.M. ALTA Owner's Policy 1992 EXTENDED SUBDIVIDER SALE -EXTENDED RATE Amount: Premium: Tax: $3,124,000.00 $4,158.00 $ 365.90 Proposed Insured: SBI DEVELOPING, L.L.C., A WASHINGTON LIMITED LIABILITY COMPANY Policy or Policies to be issued: ALT A Loan Policy Proposed Insured: Policy or Policies to be issued: ALT A Loan Policy Proposed Insured: Amount: $0.00 Premium: Tax: Amount: $0. 00 Premium: Tax: 2 . The estate or interest in the land which Is covered by this Commitment is: FEE SIMPLE 3 . Title to the estate or interest in the land is at the effective date hereof vested in: DAVID A. NYBLOM AND DEBRA L. ALBISO, HUSBAND AND WIFE, AS TO PARCEL A; AND ROBERT A. MAIR AND CLYDERAE MAIR, HUSBAND AND WIFE, AS TO PARCEL B 4 . The land referred to in this Commitment is described as follows: SEE ATTACHED LEGAL DESCRIPTION EXHIBIT WLTACOMA/RDA/0999 PARCEL A: CHICAGO TITLE INSURANCE COMPANY A.L.T.A. COMMITMENT SCHEDULE A (Continued) Order No.: 1077234 · Your No.: US LAND/SB I DEVELOPING LEGAL DESCRIPTION EXHIBIT (Paragraph 4 of Schedule A continuation) THE EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, WILLAMETTE MERIDIAN, IN KING COUNTY, WASHINGTON; EXCEPT THAT PORTION OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SAID SECTION 14 DESCRIBED AS FOLLOWS: BEGINNING AT THE SOUTHEAST CORNER OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER AS THE POINT OF TRUE BEGINNING; THENCE NORTH 00°25'21" EAST 523.99 FEET ALONG THE EAST LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER; THENCE NORTH 88°07'58" WEST 653.61 FEET TO THE WEST LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER; THENCE SOUTH 0°27'05" WEST 525.82 FEET TO THE SOUTH LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER; THENCE SOUTH 88°17'35" EAST 653.84 FEET ALONG THE SOUTH LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER TO THE TRUE POINT OF BEGINNING; AND EXCEPT COUNTY ROADS. PARCEL B: THE NORTH HALF OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, WILLAMETTE MERIDIAN, IN KING COUNTY, WASHINGTON; EXCEPT THE WEST 30 FEET CONVEYED TD KING COUNTY FOR ROAD PURPOSES BY DEED RECORDED UNDER RECORDING NUMBER 1094243. TOGETHER WITH A NON-EXCLUSIVE EASEMENT FOR INGRESS, EGRESS AND UTILITIE~ OVER, UNDER AND ACROSS THE NORTH 15 FEET OF THE WEST 187 FEET (AS MEASURED FROM THE EASTERLY MARGIN OF COUNTY ROAD RIGHT OF WAY) OF LOT 2 OF SHORT PLAT NO. 878133, RECORDED UNDER RECORDING NUMBER 8002250639, IN KING COUNTY, WASHINGTON i ~\Y'IP<:::if:.. f;'$m 'T 'Fo'R (OY'\"lt}"(l&W,C.f. ff.DYY"\ ~T n 1)U\-IY'IA~f:. i==V'tUUTY. CLTACMA6/RDA/D999 CHICAGO TITLE INSURANCE COMPANY A.LT.A. COMMITMENT SCHEDULEB Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING Schedule B of the policy or policies to be issued will contain exceptions to the following matters unless the same are disposed of to the satisfaction of the Company. GENERAL EXCEPTIONS A. Rights or clalms of parties in possession not shown by the public records. B. Encroachments, overlaps, boundary line disputes, or other matters which would be disclosed by an accurate survey and inspection of the premises. C. Easements, or claims of easements, not shown by the public records. D. Any lien, or right to a lien, for contributions to employee benefit funds, or for state workers' compensation, or for services, labor, or material heretofore or hereafter furnished, all as imposed by law, and not shown by the public records. E. Taxes or special assessments which are not shown as existing liens by the public records. F. Any service, installation, connection, maintenance, tap, capacity or construction charges for sewer, water, electricity, other utilities, or garbage collection and disposal. G. Reservations or exceptions in patents or in Acts authorizing the issuance thereof; Indian tribal codes or regulations, Indian treaty or aboriginal rights, including easements or equitable servitudes. H. Water rights, claims, or title to water. I. Defects, liens, encumbrances, adverse claims or other matters, ifany,created, first appearing in the public records, or attaching subsequent to the effective date hereof but prior to the date the proposed insured acquires of record for value the estate or interest or mortgage thereon covered by this Commitment. SPECIAL EXCEPTIONS FOLLOW WLTACOMB/RDA/0999 CHICAGO TITLE INSURANCE COMP ANY A.LT.A. COMMITMENT SCHEDULEB (Continued) Order No.: 001077234 Your No.: SPECIAL EXCEPTIONS A 1. EASEMENT AND THE TERMS AND CONDITIONS THEREOF: GRANTEE: PURPOSE: AREA AFFECTED: RECORDED: RECORDING NUMBER: KING COUNTY WATER DISTRICT NUMBER 90, A MUNICIPAL CORPORATION WATER AND SEWER MAINS WITH NECESSARY APPURTENANCES NORTHERLY 30 FEET OF PARCEL B JULY 17, 1975 7507170570 B 2. EASEMENT AND THE TERMS AND CONDITIONS THEREOF: GRANTEE: PURPOSE: AREA AFFECTED: RECORDED: RECORDING NUMBER: PUGET SOUND POWER & LIGHT COMPANY, A WASHINGTON CORPORATION ELECTRIC TRANSMISSION AND/OR DISTRIBUTION LINES A RIGHT OF WAY 10 FEET IN WIDTH HAVING 5 FEET OF SUCH WIDTH ON EACH SIDE OF A CENTERLINE DESCRIBED AS FOLLOWS: THE CENTERLINE OF GRANTEE'S FACILITIES AS CONSTRUCTED OR TO BE CONSTRUCTED, EXTENDED OR RELOCATED, LYING WITHIN PARCEL A FEBRUARY 23, 1995 9502230476 C 3. PAYMENT OF THE REAL ESTATE EXCISE TAX, IF REQUIRED. THE PROPERTY DESCRIBED HEREIN IS SITUATED WITHIN THE BOUNDARIES OF LOCAL TAXING AUTHORITY OF UNINCORPORATED KING COUNTY. PRESENT RATE IS 1.78%. ANY CONVEYANCE DOCUMENT MUST BE ACCOMPANIED BY THE OFFICIAL WASHINGTON STATE EXCISE TAX AFFIDAVIT. THE APPLICABLE EXCISE TAX MUST BE PAID AND THE AFFIDAVIT APPROVED AT THE TIME OF THE RECORDING OF THE CONVEYANCE DOCUMENTS. D 4. GENERAL AND SPECIAL TAXES ANO CHARGES, PAYABLE FEBRUARY 15, DELINQUENT IF FIRST HALF UNPAID ON MAY 1, SECOND HALF DELINQUENT IF CLTACMBl/RDA/0999 CHICAGO TITLE INSURANCE COMP ANY A.LT.A. COMMITMENT SCHEDULEB (Continued) Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING SPECIAL EXCEPTIONS UNPAID ON NOVEMBER 1 OF THE TAX YEAR (AMOUNTS 00 NOT INCLUDE INTEREST AND PENALTIES): YEAR: TAX ACCOUNT NUMBER: LEVY CODE: ASSESSED VALUE-LAND: ASSESSED VALUE-IMPROVEMENTS: GENERAL & SPECIAL TAXES: AFFECTS: PARCEL A 2004 142305-9009-04 6870 $ 257,000.00 $336,000.00 BILLED: PAID: UNPAID: $ 7,280.03 $ 3,640.02 $ 3,640.01 E 5. GENERAL AND SPECIAL TAXES AND CHARGES, PAYABLE FEBRUARY 15, DELINQUENT IF FIRST HALF UNPAID ON MAY 1, SECOND HALF DELINQUENT IF UNPAID ON NOVEMBER 1 OF THE TAX YEAR (AMOUNTS DO NOT INCLUDE INTEREST AND PENALTIES) : YEAR: TAX ACCOUNT NUMBER: LEVY CODE: ASSESSED VALUE-LAND: ASSESSED VALUE-IMPROVEMENTS: GENERAL & SPECIAL TAXES: AFFECTS: PARCEL B 2004 142305-9022-07 4350 $ 95,000.00 $110,000.00 BILLED: PAID: UNPAID: $ 2,635.06 $1,317.53 $1,317.53 F 6. DEED OF TRUST AND THE TERMS AND CONDITIONS THEREOF: GRANTOR: TRUSTEE: BENEFICIARY: AMOUNT: DAVID A. NYBLOM AND DEBRA L. ALBISO, HUSBAND AND WIFE NORTHWEST FINANCIAL CORPORATION, A WASHINGTON CORPORATION FIRST SAVINGS BANK OF WASHINGTON $ 203,150.00 CLTACMB2/RDA/0999 CHICAGO TITLE INSURANCE COMPANY A.L.T.A. COMMITMENT SCHEDULEB DATED: RECORDED: RECORDING NUMBER: LOAN NUMBER: (Continued) Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING SPECIAL EXCEPTIONS JULY21, 1995 AUGUST 1, 1995 9508010201 7 744958 17 THE AMOUNT NOW SECURED BY SAID DEED OF TRUST AND THE TERMS UPON WHICH THE SAME CAN BE DISCHARGED OR ASSUMED SHOULD BE ASCERTAINED FROM THE HOLDER OF THE INDEBTEDNESS SECURED. H AFFECTS: PARCEL A 7. DEED OF TRUST AND THE TERMS AND CONDITIONS THEREOF: GRANTOR: TRUSTEE: BENEFICIARY: AMOUNT: DATED: RECORDED: RECORDING NUMBER: LOAN NUMBER: ROBERT A. MAIR AND CLYDERAE MAIR, HUSBAND AND WIFE FIDELITY MORTGAGE TRUSTEE SERVICE, A CALIFORNIA CORPORATION IMC MORTGAGE COMPANY DBA COREWEST MORTGAGE COMPANY $122,000.00 JULY 18, 1997 JULY31, 1997 9707311685 3WA-11028 THE AMOUNT NOW SECURED BY SAID DEED OF TRUST AND THE TERMS UPON WHICH THE SAME CAN BE DISCHARGED OR ASSUMED SHOULD BE ASCERTAINED FROM THE HOLDER OF THE INDEBTEDNESS SECURED. J AFFECTS: PARCEL B L 8. DEED OF TRUST AND THE TERMS AND CONDITIONS THEREOF: GRANTOR: TRUSTEE: BENEFICIARY: AMOUNT: DAVID A. NYBLOM AND DEBRA L. ALBISO, HUSBAND AND WIFE CHICAGO TITLE INSURANCE COMPANY KING COUNTY CREDIT UNION $ 98,000.00 CLTACMBZ/RDA/0999 CHICAGO TITLE INSURANCE COMPANY A.LT.A. COMMITMENT SCHEDULEB (Continued} Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING DATEO: RECORDED: RECORDING NUMBER: LOAN NUMBER: SPECIAL EXCEPTIONS SEPTEMBER 17, 2001 SEPTEMBER 24, 2001 20010924002679 NOT DISCLOSED THE AMOUNT NOW SECURED BY SAID DEED OF TRUST AND THE TERMS UPON WHICH THE SAME CAN BE DISCHARGED OR ASSUMED SHOULD BE ASCERTAINED FROM THE HOLDER OF THE INDEBTEDNESS SECURED. U AFFECTS: PARCEL A Z 9. MATTERS DISCLOSED BY SURVEY RECORDED UNDER RECORDING NUMBER 9508099008, AS FOLLOWS: A. BARN APPURTENANT TO PARCEL A ENCROACHES UP TO 1.0 FEET INTO SOUTHERLY ADJOINER; B. FENCES NEAR WESTERLY AND SOUTHERLY PROPERTY BOUNDARIES OF PARCEL A DO NOT CONFORM WITH PROPERTY LINES. N 10. A PORTION OF THE IMPROVEMENTS LOCATED ON THE HEREIN DESCRIBED PROPERTY WAS PREVIOUSLY A MOBILE HOME WHICH HAS BEEN CONVERTED TO REAL PROPERTY BY MANUFACTURED HOME TITLE ELIMINATION CERTIFICATE RECORDED UNDER RECORDING NUMBER 20010919001892. 0 AFFECTS: PARCEL B P 11. RIGHT, TITLE AND INTEREST OF U.S. LAND DEVELOPMENT ASSOCIATES, A WASHINGTON GENERAL PARTNERSHIP, PRESUMED BY THE APPLICATION FOR TITLE INSURANCE TO HAVE AN INTEREST IN SAID PREMISES. Q NOTE: SAID INTEREST, IF ANY, IS SUBJECT TO THE FOLLOWING MATTERS SHOWN AT PARAGRAPHS 12 AND 13. R 12. TERMS AND CONDITIONS OF THE PARTNERSHIP AGREEMENT FOR U.S. LAND DEVELOPMENT ASSOCIATES. S NOTE: A COPY OF THE PARTNERSHIP AGREEMENT, AND AMENDMENTS THERETO, IF ANY, MUST BE SUBMITTED. CLTACMB2/ROA/0999 CHICAGO TITLE INSURANCE COMP ANY A.LT.A. COMMITMENT SCHEDULEB (Continued) Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING SPECIAL EXCEPTIONS T 13. ANY CONVEYANCE OR MORTGAGE BY U.S. LAND DEVELOPMENT ASSOCIATES, MUST BE EXECUTED IN ACCORDANCE WITH THE PARTNERSHIP AGREEMENT AND BY ALL THE GENERAL PARTNERS AND THEIR RESPECTIVE SPOUSES AS OF THE DATE OF ACQUISITION, OR EVIDENCE MUST BE SUBMITTED THAT CERTAIN DESIGNATED PARTNERS HAVE BEEN AUTHORIZED TO ACT FOR THE PARTNERSHIP. AK 14. PHYSICAL INSPECTION MADE MARCH 4, 2003 VERIFIED THE REQUIREMENT FOR A SURVEY DUE TO LACK OF ACCESS TO SITE AND OVERALL SIZE OF PROPERTY. Y 15. PRIOR TO ISSUING AN EXTENDED FORM OWNER'S POLICY THIS COMPANY REQUIRES THAT THE PARTIES TO THE TRANSACTION PROVIDE AN ALTA/ASCM CERTIFIED. AS-BUILT SURVEY. AD 16. THE LEGAL DESCRIPTION IN THIS COMMITMENT IS BASED ON INFORMATION PROVIDED WITH THE APPLICATION AND THE PUBLIC RECORDS AS DEFINED IN THE POLICY TO ISSUE. THE PARTIES TO THE FORTHCOMING TRANSACTION MUST NOTIFY THE TITLE INSURANCE COMPANY PRIOR TO CLOSING IF THE DESCRIPTION DOES NOT CONFORM TO THEIR EXPECTATIONS. AF 17. IT IS OUR UNDERSTANDING THAT THE INTENDED TRANSACTION INVOLVES THE SUBDIVISION OF PARCEL B BY MEANS OF A LOT LINE ADJUSTMENT. UPON THE SUBMISSION AND REVIEW OF THE FINAL LEGAL DESCRIPTION OF THE PROPERTY TO BE CONVEYED, THIS COMMITMENT WILL BE REVISED ACCORDINGLY. AE THE PREMIUM FOR THE FORTHCOMING OWNER'S POLICY IS COMPUTED AS FOLLOWS: STANDARD COVERAGE - EXTENDED SURCHARGE - INSPECTION FEE - Al NOTE 1: $ 2,138.00 PLUS TAX OF$ 188.14 $1,870.00 PLUS TAX OF$ 164.56 $ 150.00 PLUS TAX OF$ 13.20 IN THE EVENT THE OWNER'S POLICY COVERAGE IS CHANGED FROM EXTENDED TO STANDARD COVERAGE A CHARGE OF $150.00, PLUS $13.20 SALES TAX, WILL BE ADDED TO COVER THE COSTS RELATING TO THE EXTENDED COVERAGE INSPECTION. AA NOTE 2: EFFECTIVE JANUARY 1, 1997, DOCUMENT FORMAT AND CONTENT REQUIREMENTS HAVE BEEN IMPOSED BY WASHINGTON LAW. FAILURE TO COMPLY WITH THE FOLLOWING REQUIREMENTS MAY RESULT IN REJECTION OF THE DOCUMENT BY THE CLTACMB2/RDA/0999 CHICAGO TITLE INSURANCE COMPANY A.L.T.A. COMMITMENT SCHEDULEB (Continued) Order No.: 1077234 Your No.: US LAND/SB I DEVELOPING SPECIAL EXCEPTIONS COUNTY RECORDER OR IMPOSITION OF A $50.00 SURCHARGE. FIRST PAGE OR COVER SHEET REQUIREMENTS: 3" TOP MARGIN CONTAINING NOTHING EXCEPT THE RETURN ADDRESS. 1 '' SI DE AND BOTTOM MARG I NS CONTAIN I NG NO MARK I NGS OR SEALS. TITLE(S) OF DOCUMENTS. RECORDING NO. OF ANY ASSIGNED, RELEASED OR REFERENCED DOCUMENT(S). GRANTORS NAMES (AND PAGE NO. WHERE ADDITIONAL NAMES CAN BE FOUND). GRANTEES NAMES (AND PAGE NO. WHERE ADDITIONAL NAMES CAN BE FOUND). ABBREVIATED LEGAL DESCRIPTION (AND PAGE NO. FOR FULL DESCRIPTION). ASSESSOR'S TAX PARCEL NUMBER(S). RETURN ADDRESS (IN TOP 3" MARGIN). **A COVER SHEET CAN BE ATTACHED CONTAINING THE ABOVE FORMAT AND DATA IF THE FIRST PAGE DOES NOT CONTAIN ALL REQUIRED DATA. ADDITIONAL PAGES: 1" TOP, SIDE AND BOTTOM MARGINS CONTAINING NO MARKINGS OR SEALS. ALL PAGES: NO STAPLED OR TAPED ATTACHMENTS. EACH ATTACHMENT MUST BE A SEPARATE PAGE. ALL NOTARY AND OTHER PRESSURE SEALS MUST BE SMUDGED FOR VISIBILITY. FONT SIZE OF 8 POINTS OR LARGER. ALL INFORMATION MUST BE LEGIBLE AND CAPABLE OF BEING IMAGED. THE FOLLOWING MAY BE USED AS AN ABBREVIATED LEGAL DESCRIPTION ON THE DOCUMENTS TO BE RECORDED TO COMPLY WITH THE REQUIREMENTS OF RCW 65.04. SAID ABBREVIATED LEGAL DESCRIPTION IS JIQT A SUBSTITUTE FOR A -COMPLETE LEGAL DESCRIPTION WHICH MUST ALSO APPEAR frir THE BODY OF THE DOCUMENT: POR OF NW 1/4 OF SE 1/4 OF SEC 14, TWP 23 N, RGE 5 E, W.M. END OF SCHEDULE B CLTACMBURDA/0~99 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN: A. Hydraulic Analysis The drainage analysis was modeled using the King County Runoff Time Series software. The onsite soils are Alderwood (AgC), KCRTS group Till per the Soils Map attached on the following pages. The site is located in the Sea-Tac rainfall region with a location scale factor of 1.0. EXISTING CONDITIONS TRADING OF EXISTING IMPERVIOUS PAVEMENT FOR PROPOSED IMPERVIOUS AREA BYPASSING DETENTION/WATER QUALITY FACILITIES Areas of road improvements along SE 1361h Street and shoulder addition along 1601 h Avenue SE will be bypassing the proposed storm drainage facilities. As a trade off, existing asphalt areas equal to or more than the bypass areas will be collected and treated within the proposed storm drainage facilities. The existing asphalt areas will be considered pasture in the existing condition and impervious in the proposed condition. Since these existing impervious surfaces were not treated and/or detained for in the past, the total runoff from the bypass areas plus the outflows from the detention/water quality facilities will be the same or less than the outflows as they exist today. See Existing and Developed Conditions Exhibit on the following pages for delineation of the existing impervious areas to be collected and proposed pavement areas to be bypassed. WEST BASIN The basin boundary delineated for the West Basin includes the development and SE 1361h Street west of the existing basin ridge. A portion of the most western portion of SE 1361 h Street will not be included in the existing condition, i.e. not captured in the proposed drainage system, since an equal amount of existing asphalt will be included within the developed West Basin and treated as pasture in the existing condition. For the reasons stated above, detention does not need to account for the bypass area since existing asphalt will be treated in the place of the bypass impervious surfaces. The western portion of the site is 1.81 acres. The existing coverage is a combination of impervious surfaces associated with the existing outbuildings, pasture, landscaping, lawn, and forest. The existing landscaping and lawn will be considered pasture per Table 3.2.2.C in the 1998 KCSWDM for existing developed areas with densities less than 4 DU/AC. The site is covered with 1.57 acres of pasture and 0.20 acre of forest. Existing impervious surfaces from the existing outbuildings cover a total area of 0.04 acre. Per Table 3.2.2.E in the 1998 KCSWDM, the effective impervious fraction for the site is 0.40 for existing rural areas. The effective impervious area is therefore 0.40*0.04 acre= 0.02 acre. Pasture will be utilized for the non-effective impervious surfaces (0.04 acre -0.02 acre= 0.02 acre). The following information was used for generating time series and flow frequencies. 3.2.2 KCRTS/RUNOFF ALES METHOD-GENERATING TIME SERIES SCS Soil Type scs KCRTS Soil Notes Hydrologic Group Soil Group ----';5> Alderwood (AgB, Age, AgD) e {Till) Arents, Alderwood Material (AmB, Ame) e Till Arents, Everett Material (An) B Outwash 1 Beausite (Bee, BeD, BeF) C Till 2 Bellingham (Bh) D Till 3 Brisco! (Br) D Till 3 Buckley (Bu) D Till 4 Earlmont (Ea) D Till 3 Edgewick (Ed) C Till 3 Everett (EvB, Eve, EvD, EwC) A/B Outwash 1 Indianola (lne, lnA, lnD) A Outwash 1 Kitsap (KpB, KpC, KpD) C Till Klaus (Kse) C Outwash 1 Neilton (NeC) A Outwash 1 Newberg (Ng) B Till 3 Nooksack (Nk) C Till 3 Norma (No) D Till 3 Orcas (Or) D Wetland Oridia (Os) D Till 3 Ovall (Ove, OvD, OvF) e Till 2 Pilchuck (Pc) C Till 3 Puget (Pu) D Till 3 Puyallup (Py) B Till 3 Ragnar (Rae, RaD, RaC, RaE) B Outwash 1 Renton (Re) D Till 3 Salal (Sa) C Till 3 Sammamish (Sh) D Till 3 Seattle (Sk) D Wetland Shalcar (Sm) D Till 3 Si (Sn) C Till 3 Snohomish (So, Sr) D Till 3 Sultan (Su) e Till 3 Tukwila (Tu) D Till 3 Woodinville (Wo) D Till 3 Notes: 1. Where outwash soils are saturated or underlain at shallow depth ( <5 feet) by glacial till, they should be treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King County DNR shows bedrock soils to have similar hydrologic response to till soils. 3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water table. In the absence of detailed study, these soils should be treated as till soils. 4. Buckley soils are formed on the low-permeability Osceola mudflow. Hydrologic response is assumed to be similar to that of till soils. 1998 Surface Water Design Manual 9/1/98 3-25 ST 1.1 ST 1.0 Rainfall Regions andl Regional Scale !Factors 12.':"Z::,l Incorporated Area --..= River/Lake Major Road LA 1.0 LA 1.2 EAST BASIN The basin boundary delineated for the East Basin includes the development, SE l 36'h Street east of the existing basin ridge, and a portion of 160'h Avenue SE. A portion of the shoulder additional along 160'h Avenue SE will not be included in the existing condition, i.e. not captured in the proposed drainage system, since an equal amount of existing asphalt will be included within the existing/developed East Basin and treated as pasture in the existing condition. For the reasons stated above, detention does not need to account for the bypass area since existing asphalt will be treated in the place of the bypass impervious surfaces. The eastern portion of the site is I 0.06 acres. The existing coverage is a combination of impervious surfaces associated with the existing residence, pasture, landscaping, lawn, and forest. The existing landscaping and lawn will be considered pasture per Table 3.2.2.C in the 1998 KCSWDM for existing developed areas with densities less than 4 DU/AC. The site is covered with 3.00 acres of pasture and 6.62 acres of forest. Existing impervious surfaces from the existing residence and outbuildings cover a total area of 0.44 acre. Per Table 3.2.2.E in the 1998 KCSWDM, the effective impervious fraction for the site is 0.40 for existing rural areas. The effective impervious area is therefore 0.40*0.44 acre= 0.18 acre. Pasture will be utilized for the non-effective impervious surfaces (0.44 acre -0.18 acre= 0.26 acre). The following information was used for generating time series and flow frequencies. EAST BASIN Total Area= 10.06 acres EXISTING CONDITIONS .. (ex east) GROUND COVER AREA(acre) Till-Forest 6.62 Till-Pasture (3.00 + 0.26) 3.26 Imoervious 0.18 DEVELOPED CONDITIONS The developed basin ridge delineated and allowed per SWM Adjustment L02V0024 was regraded at a different location than what currently exists. See Existing and Developed Conditions Exhibit on the following pages. The relocation was logical based on the property boundary and basin ridge relationship. A small triangle of area adjacent to the existing basin ridge within the existing West Basin is currently located at the most southwestern end of the property. This triangle of area is approximately 300' from the West Basin located within the property boundary, therefore this small area will be conveyed to the East Basin in the developed condition and an equal amount of area within the existing East Basin located along adjacent to the basin ridge at the north end of the site will be conveyed to the West Basin. Since an adjustment was required to relocate the basin ridge, an automatic 10% safety factor was added to the detention calculations. The maximum impervious area per lot was calculated using the criteria in the 1998 King County Surface Water Design Manual page 3-27 and K.C.C.2 lA.12.030. The proposed development is urban residential. The site is R-6 zoning. The maximum impervious area per lot is 70%. WEST BASIN The lots within the West Basin cover a total area of 1.15 acres. Maximum Lot Impervious Area= 70%* 1.15 acres= 0.81 acre West Basin Impervious Area Delineation Onsite road and sidewalk 0.49 acres Impervious area of Jots 0.81 acres Total impervious area 1.30 acres The input used for the KCRTS analysis is summarized in the table below: WEST BASIN Total Area= 1.81 acres DEVELOPED CONDITIONS (devwest) GROUND COVER AREA(acre) Till-Grass (Landscaping) 0.51 Impervious 1.30 21 A.12.030 A. Densities and dimensions -residential zones ··--... RESIDENTIAL z RUlW. URBAN URBAN D N RESERVE ... _ E s STANDARDS RA-2.5 .... RA-10 RA-20 UR R·1 R-4 ~ ... R-1Z .... R·24 R-48. 1171 --02 0., a, .... 0., 1 • • ' 12 11 24 .. -du/ac ..... ·--..... ..... . ., .. ..... ·--..... ·-..... -(21) t6) (15) Maximum DensJty: ... ... • 9 12 11 27 ,. 72 o-atng Unltf.Acre ""'" ..... ·-·---..... ·-..... (1) (20) (20) (22) tnnwum Density: .... .... IS% .... "" 70% "" (2) (12) (12) (12) (18) (18) (18) (18) (18) (18) (18) (23) M-.ml.ot 135ft 135ft 135ft "135ft ,.. 35ft 30ft 30ft 30ft 30 ft 30ft ••• 30ft Wld1h (7) (7) (3) --... ... 30ft ... 30ft 20ft 10ft 10 ft 10ft 10 ft 10ft 10ft 10 ft -(9) (9) 19) 19) (7) (7) (0) Ill _19) '" II) {8) {8) (3) Minimum-5ft 10ft 10 ft 10ft •• 5ft 5ft •• 5ft 5ft 5ft •• 5ft ....... {9) {9) {9) (9) (7) (7) (10) (10) (10) (10) (3) 118) BaMHelght ... ... ... ... 35ft ... ... ... 35ft ... ... .. . .. . 141 .... .... ... ... ... 11.4) (14) {14) (14) {14) / Maximum \ '"' 20% 15" 12.5% -30% "" 70% 75" "" 85% 85% -I lmp,mous (11) (11) (11) {11) {11) {11) .__/ ·-J (19) (19) (19) (19) \. Percantage (5) 12-2 (King County 6-00) B. Detention Routing Calculations Per the Hearing Examiner's Conditions, the West Basin wetvault will mitigate for increased drainage flows from the developed West Basin utilizing Level 3 Flow Control. The East Basin wetpond will mitigate for increased drainage flows from the developed East Basin utilizing Level 2 Flow Control. All stormwater mitigation facilities will be designed according to the 1998 KCSWDM. Since an adjustment was required to relocate the basin ridge, an automatic I 0% safety factor was added to the detention calculations. WESTBASfN The West Basin will utilize a wetvault to accommodate the required Level 3 Flow Control. The West Basin wetvault (wvault.rdf) was sized based on the 1998 KCSWDM and KCRTS Computer Software Reference Manual. See attached KCRTS printouts. The wetvault per KCRTS will have a surface area of2,967 square feet and a depth of7.42 feet. To accommodate the required I 0% safety factor, the vault will be constructed with a surface area of 3,264 square feet (34 feet by 96 feet). West Basin Wetvault Overflow Elevation The primary overflow for the vault is the riser pipe within the control structure. The water surface elevation above the riser for the 100 year developed flow is calculated assuming all orifices are plugged. To pass the JOO-year return period storm, 0.72 cfs, through a 12" overflow riser will require 0.47 feet of head (From Figure 5.3.4.H in the 1998 KCSWDM: Qweir = 9.739DH 312 => 0.72 = 9.739(12/12)H312 => H = 0.18 feet). The primary overflow elevation would therefore, be equal to the elevation of the top of the riser plus the amount of head required to pass the I 00-year return period storm, Elev. 478.47 + 0.18 feet= Elev. 478.65. The ceiling of the vault is located at elevation 459.0 and will accommodate the required overflow elevation. Retention/Detention Facility l_L)\/ f\L)LT. DOG Type of Facility, Detention Vault ,~/ Facility Length, 87.27 ft ..-- Facility Width, 34.00 ft~ Facility Area: 2967. sq. ft Effective Storage Depth, 7.42 ft Stage 0 Elevation: 471.08 ft Storage Volume: 22016. cu. ft 7.4i.. Riser Head: 7. 39 ft v' Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.81 0.048 2 3.60 1.20 0.076 4.0 3 5.20 0.50 0.010 4.0 Top Notch Weir, None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 471.08 89. 0.002 0.000 0.00 0.01 471.09 119. 0.003 0.002 0.00 0.02 471.10 148. 0.003 0.002 0.00 0.03 471.11 178. 0.004 0.003 0.00 0.04 471.12 20·9. 0.005 0.004 0.00 0.05 4 71.13 237. 0.005 0.004 0.00 0.06 471.14 267. 0.006 0.004 0.00 0.07 471.15 297. 0.007 0.005 0.00 0.21 471.29 712. 0.016 0.008 0.00 0.36 471. 44 1157. 0.027 0.011 0.00 0.50 471.58 1573. 0.036 0.013 0.00 0.65 471.73 2018. 0.046 0. 014 0.00 0.79 471.87 2433. 0.056 0.016 0.00 0.94 472.02 2 87 8. 0.066 0.017 0.00 1. 08 4 72. 16 3294. 0.076 0.019 0.00 1. 23 472.31 3739. 0.086 0.020 0.00 1. 37 472.45 4154. 0.095 0.021 0.00 1. 52 4 72. 60 4599. 0.106 0.022 0.00 1.66 472.74 5015. 0 .115 0.023 0.00 1. 81 472.89 5460. 0.125 0.024 0.00 1. 95 473.03 5875. 0 .135 0.025 0.00 2.10 473.18 6320. 0 .145 0.026 0.00 2.24 473.32 6736. 0.155 0.027 0.00 2.39 473.47 7181. 0.165 0.027 0.00 2.53 473.61 7596. 0.174 0.028 0.00 2.68 473.76 8041. 0.185 0.029 0.00 2.82 473.90 8457. 0.194 0.030 0.00 2. 97 474.05 8902. 0.204 0.031 0.00 3 .11 474.19 9317. 0.214 0.031 0.00 3.26 474.34 9762. 0.224 0.032 0.00 3.40 474.48 10177. 0.234 0.033 0.00 3.55 474.63 10623. 0.244 0.034 0.00 3.60 474.68 10771. 0.247 0.034 0.00 3.61 474.69 10801. 0.248 0.034 0.00 3. 63 474.71 10860. 0.249 0.035 0.00 3.64 474.72 10890. 0.250 0.037 0.00 3.65 474.73 10919. 0.251 0.039 0.00 3.66 474.74 1094 9. 0.251 0. 041 0.00 3.68 474.76 11008. 0.253 0.045 0.00 3.69 474.77 11038. 0.253 0.046 0.00 3.70 474.78 11068. 0. 254 0.047 0.00 3.84 474.92 11483. 0.264 0.054 0.00 3.99 475.07 1192 8. 0.274 0.060 0.00 4 .13 475.21 12343. 0.283 0.065 0.00 4.28 475.36 12789. 0.294 0.069 0.00 4.42 475.50 13204. 0.303 0.073 0.00 4.57 475.65 13649. 0 .313 0.076 0.00 4.71 475.79 14064. 0.323 0.080 0.00 4.86 475.94 14510. 0.333 0.083 0.00 5.00 476.08 14 925. 0.343 0.086 0.00 5 .15 476.23 15370. 0.353 0.089 0.00 5.20 476.28 15518. 0.356 0.090 0.00 5.21 476.29 15548. 0.357 0.090 0.00 5.22 476.30 15578. 0.358 0.091 0.00 5.23 476.31 15607. 0.358 0.092 0.00 5.24 476.32 15637. 0.359 0. 092 0.00 5.39 476.47 16082. 0.369 o. 096 0.00 5.53 476.61 16498. 0.379 0.100 0.00 5.68 476.76 16943. 0.389 0.103 0.00 5.82 476.90 17358. 0.398 0.106 0.00 5.97 477.05 17803. 0.409 0.109 0.00 6 .11 477.19 18218. 0 .418 0 .112 0.00 6.26 477.34 18664. 0.428 0 .115 0.00 6.40 477.48 19079. 0.438 0 .118 0.00 6.55 477.63 19524. 0.448 0.120 0.00 6.69 477.77 1993 9. 0.458 0.123 0.00 6. 84 477.92 20385. 0.468 0.125 0.00 6.98 478.06 20800. 0.478 0.128 0.00 7 .13 478.21 21245. 0.488 0 .130 0.00 7.27 478.35 21660. 0.497 0 .133 0.00 __ 7-,,3.9 478.47 22016. 0.505 0 .134 0.00 7.49 478.57 22313. 0.512 0.444 0.00 7.59 478.67 22610. 0.519 1.010 0.00 7.69 478.77 22907. 0.526 1. 740 0.00 7.79 478.87 23203. 0.533 2.530 0.00 7.89 478.97 23500. 0.539 2.820 0.00 7.99 479.07 23797. 0.546 3.070 0.00 8.09 479.17 24094. 0.553 3.310 0.00 8.19 479.27 24390. 0.560 3.530 0.00 8.29 479.37 24687. 0.567 3.740 0.00 8. 39 479.47 24984. 0.574 3.930 0.00 8.49 479.57 25280. 0.580 4 .120 0.00 8.59 479.67 25577. 0.587 4.290 0.00 8.69 479.77 25874. 0. 594 4.470 0.00 8.79 479.87 26171. 0.601 4.630 0.00 8.89 479.97 26467. 0.608 4.790 0.00 8.99 480.07 26764. 0. 614 4.940 0.00 9.09 4 80. 17 27061. 0.621 5.090 0.00 9.19 480.27 27357. 0.628 9.29 480.37 27654. 0.635 Hyd Inflow Outflow Peak Target Cale Stage Elev 1 o. 72 0.22 0.22 7.42 478.50 2 0.36 ******* 0.12 6.54 477.62 3 0.37 ******* 0 .11 5.87 476.95 4 0. 38 ******* 0.09 5.07 476.15 5 0.43 ******* 0.09 5.01 476.09 6 0.23 ******* 0.06 3.91 474.99 7 0.30 ******* 0.03 3.29 474.37 8 0.33 ******* 0.03 2.75 473.83 Route Time Series through Facility Inflow Time Series File:devwest.tsf Outflow Time Series File:wout Inflow/Outflow Analysis 5.230 0.00 5.370 0.00 Storage (Cu-Ft) (Ac-Ft) 22102. 0.507 194 96. 0.448 17498. 0.402 15128. 0.347 14956. 0.343 11683. 0.268 9839. 0.226 8260. 0.190 Peak Inflow Discharge: 0. 722 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge; 0.222 CFS at 11 :00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.42 Ft Peak Reservoir Elev: 478.50 Ft Peak Reservoir Storage: 22102. Cu-Ft 0.507 Ac-Ft Flow Frequency Analysis Time Series File:wout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.120 2 2/09/01 20:00 0.032 7 12/28/01 18:00 0.086 5 3/06/03 22:00 0.030 8 8/26/04 7:00 0.057 6 1/05/05 15:00 0.087 4 1/18/06 23:00 0.107 3 11/24/06 7:00 0.222 1 1/09/08 11: 00 Computed Peaks -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft) Period 0.222 7.42 1 100.00 0.990 0.120 6.54 2 25.00 0. 960 0.107 5.87 3 10.00 0.900 0.087 5.07 4 5.00 0.800 0.086 5.01 5 3.00 0.667 0.057 3.91 6 2.00 0.500 0.032 3.29 7 1. 30 0.231 0.030 2.77 8 1.10 0. 091 0.188 7 .41 50.00 0.980 Flow Duration from Time Series File:wout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.002 34644 56.497 56.497 43.503 0.435E+OO 0.005 4824 7.867 64.364 35.636 0.356E+OO 0.008 5399 8.805 73.169 26.831 0.268E+OO 0.012 3897 6.355 79.524 20.476 0.205E+OO 0.015 4088 6.667 86.190 13.810 0 .138E+OO 0.018 2706 4. 413 90.603 9. 397 0.940E-01 0.022 2069 3.374 93.977 6.023 0.602E-01 0.025 1286 2.097 96. 07 5 3. 925 0.393E-01 0.028 1042 1.699 97.774 2.226 0.223E-01 0.032 703 1.146 98.920 1.080 O.lOBE-01 ) 0.035 327 0.533 99.454 0.546 0.546E-02 0.039 7 0.011 99.465 0.535 0.535E-02 0.042 11 0.018 99.483 0.517 0.517E-02 0. 045 12 0.020 99.503 0.497 0.497E-02 0. 049 32 0.052 99.555 0.445 0.445E-02 0.052 35 0.057 99.612 0.388 0.388E-02 0.055 31 0.051 99.662 0.338 0.338E-02 0.059 20 0.033 99.695 0.305 0.305E-02 0.062 13 0.021 99.716 0.284 0. 284E-02 0.065 12 0.020 99.736 0. 264 0.264E-02 0.069 16 0.026 99.762 0.238 0.238E-02 0. 072 16 0.026 99.788 0. 212 0.212E-02 0.075 18 0.029 99.817 0.183 0.183E-02 0.079 18 0.029 99.847 0.153 0.153E-02 0.082 19 0.031 99.878 0.122 0.122E-02 0.085 10 0.016 99. 894 0.106 0.106E-02 0.089 17 0.028 99. 922 0.078 0.783E-03 0.092 5 0.008 99.930 0.070 0.701E-03 0.095 10 0.016 99.946 0.054 0.538E-03 0.099 3 0.005 99.951 0.049 0.489E-03 0 .102 7 0.011 99. 962 0.038 0.375E-03 0.105 5 0.008 99. 971 0.029 0. 294E-03 0.109 6 0.010 99.980 0.020 0 .196E-03 0 .112 2 0.003 99.984 0.016 0.163E-03 0.116 3 0.005 99.989 0. 011 0 .114E-03 0 .119 4 0.007 99.995 0.005 0.489E-04 Duration Comparison Anaylsis Base File: exwest.tsf New File: wout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.034 0.81E-02 0.71E-02 -12.1 I 0.81E-02 0.034 0.033 -1. 4 0. 041 0.59E-02 0.52E-02 -11.1 I 0.59E-02 0.041 0.034 -17.3 0.048 0.46E-02 0.45E-02 -2. 8 I 0.46E-02 0.048 0.048 -1. 3 0.056 0.34E-02 0.33E-02 -2. 4 I 0.34E-02 0.056 0.055 -1. 4 0.063 0.26E-02 0.28E-02 5.6 I 0.26E-02 0.063 0.066 4.9 0.070 0.19E-02 0.23E-02 19.8 I 0.19E-02 0.070 0.075 6.0 0.078 0 .14E-02 0.16E-02 15.3 I 0.14E-02 0.078 0.081 3.7 0.085 0. 96E-03 0. llE-02 10.2 I 0.96E-03 0.085 0.086 1.3 0. 092 0.68E-03 0.68E-03 0.0 I 0.68E-03 0.092 0.092 0.0 0.100 0.41E-03 0.47E-03 16.0 I 0.41E-03 0.100 0.102 2.3 0.107 0.21E-03 0.26E-03 23.1 I 0.21E-03 0.107 0.109 1. 7 0 .114 0.15E-03 0 .13E-03 -11.1 I 0.15E-03 0.114 0 .113 -0.6 0.121 0.65E-04 O.OOE+OO -100.0 I o:65E-04 0.121 0 .119 -2.4 Maximum positive excursion= 0.004 cfs ( 6.4%) occurring at 0.070 cfs on the Base Data:exwest.tsf and at 0.075 cfs on the New Data:wout.tsf Maximum negative excursion= 0.008 cfs {-18.7%) occurring at 0.043 cfs on the Base Data:exwest.tsf and at 0.035 cfs on the New Data:wout.tsf EAST BASIN The East Basin will utilize a wetpond to accommodate the required Level 2 Flow Control. The East Basin wetpond will receive runoff from the upstream tributary area as well as runoff from onsite. The upstream tributary area will be routed through the onsite storm drainage system to the wetpond. The allowable release rates will be established by the sum of the upstream tributary runoff plus the existing onsite runoff. The allowable release rate will be delineated as preeast.tsf and will be the sum of exeast.tsf + upsteast.tsf. The flows entering the wetpond will be the sum of the upstream tributary area and the developed site going to the pond. The total developed flows discharging to the pond will be delineated as posteast.tsf and will be the sum of deveast.tsf and upsteast.tsf. The East Basin wetpond ( epond.rdf) was sized based on the 1998 KCSWDM and KCRTS Computer Software Reference Manual. See attached KCRTS printouts and attached pond volume calculation spreadsheet on the following pages. The stage-storage of the pond produced by KCRTS was utilized to calculate storage values at the elevations used to calculate the proposed wetpond that will actually be constructed onsite. The KCRTS interpolated storage values are listed below. Elevation sf Length x Width KCRTS Storage KCRTS Storage* 10% Safety Factor 451 °'lt,t 225' X 43' 0 0 452 II 7 ~0 230' X 51' 11,265 CF 12,391 CF 454 I~ o<f:o 235' X 64' 39,600 CF 39,600 CF 456 I°[ 04-D 238' X 80' 73,986 CF 81,384 CF 458 ., ..., ,,. -.. 240' X 85' 115,605 CF 127,165 CF Per the proposed Pond Volume Calculations spreadsheet on the following pages, the storage values at each delineated elevation is more than the required 10% safety factor storage values calculated above. The pond is therefore, adequately sized to accommodate the required I 0% safety factor. 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: Detention Pond 3.00 H:lV 165.00 ft ../ 67. 00 ft / 11055. sq. ft 24299. sq. ft 0.558 acres 6.90 ft 451.00 ft 113358. cu. ft 2.602 ac-ft 6.90 ft 18.00 inches 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1. 75 0.160 2 4.70 3.00 0.362 6.0 3 5.60 2.00 0.124 4.0 Top Notch Weir: None -Outflow Rating Curve: None Q, b'tb lf~ Stage Elevation Storage Discharge Percolation ( ft) (ft) (cu. ft) (ac-ft) (cf s) (cfs) 0.00 451.00 o. 0.000 0.000 0.00 0.02 451.02 221. 0.005 0. 011 0.00 0.04 451.04 443. 0.010 0.016 0.00 0.05 451. 05 555. 0.013 0.019 0.00 0.07 451.07 777. 0.018 0. 022 0.00 0.09 451.09 1001. 0.023 0.025 0.00 0 .11 451.11 1225. 0.028 0. 027 0.00 0.13 451.13 1449. 0. 033 0.030 0.00 0.15 451.15 1674. 0.038 0.032 0.00 0.28 451.28 3150. 0. 072 0.044 0.00 0.42 451. 42 4767. 0.109 0.054 0.00 0.55 451.55 6293. 0.144 0.062 0.00 0.69 451. 69 7963. 0.183 0.069 0.00 0.82 451. 82 9540. 0.219 0.075 0.00 0.96 451. 96 1~ 11265/ 0.259 0.081 0.00 1. 09 452.09 ,i.0 12892: 0.296 0.087 0.00 1. 23 452.23 14673. 0.337 0.092 0.00 1.36 452.36 16352. 0.375 0.097 0.00 1.50 452.50 18189. 0.418 0.102 0.00 1. 63 452.63 19921. 0.457 0.106 0.00 1. 77 452.77 21814. 0.501 0.110 0.00 1. 90 452.90 23599. 0.542 0.115 0.00 2.04 453.04 25551. 0.587 0 .119 0.00 2 .18 453.18 27532. 0.632 0.123 0.00 2.31 453.31 29399. 0.675 0 .126 0.00 2.45 453.45 314 3 9. 0.722 0.130 0.00 2.58 453.58 33361. 0.766 0 .133 0.00 ,..,; _.... Surf Area (sq. ft) 11055. 11083. 11111. 11125. 11153. 11181. 11209. 11237. 11265. 11448. 11646. 11831. 12033. 12221. 12424. 12615. 12822. 13015. 13224. 13420. 13632. 13830. 14044. 14261. 14463. 14681. 14886. 2. 72 453. 72· 35460. 0.814 0 .137 0.00 15108. 2.85 453.85 37438. 0.859 0.140 0.00 15315. 2.99 453.99 39598. 0.909 0.144 0.00 15539. 3.12 454.12 41631. 0.956 0.147 0.00 15748. 3.26 454.26 43852. 1. 007 0.150 0.00 15976. 3.39 454.39 45942. 1. 055 0.153 0.00 16188. 3.53 454.53 48225. 1.107 0.156 0.00 16417. 3.66 454.66 50373. 1.156 0.159 0.00 16632. 3.80 ·454.80 52718. 1. 210 0.162 0.00 16864. 3. 93 454.93 54924. 1. 261 0.165 0.00 17082 . 4.07 . --4.5.5_._0_7 __ 57332. 1. 316 _o ... 168~-0.00 _1_7_31.7 ____ 4.20 455.20 59597. 1. 368 0.170 0.00 17536. 4.34 455.34 62069. 1. 425 0.173 0.00 17774. 4.48 455.48 64574. 1.482 0.176 0.00 18014. 4.61 455.61 66931. 1. 537 0.178 0.00 18237. 4.70 455.70 68579. 1. 574 0.180 0.00 18393. 4.73 455.73 69132. 1.587 0.183 0.00 18445. 4.76 455.76 69686. 1. 600 0.190 0.00 18497. 4.79 455.79 70241. 1. 613 0.202 0.00 18549. 4.82 455.82 70799. 1. 625 0.219 0.00 18601. 4.86 455.86 71544. 1. 642 0.238 0.00 18670. 4.89 455.89 72105. 1. 655 0.263 0.00 18723. 4. 92 455.92 72667. 1. 668 0.289 0.00 18775. 4.95 455.95 73231. 1.681 0.307 -i-'t< 0.00 18827. 5.09 456.09 75884. 1. 742 o. 339 ce\v-Sl-o. oo 19073. 5.22 456.22 78379. 1. 799 0.366 0.00 19302. 5. 36 456.36 81098. 1. 862 0.390 0.00 19550. 5.49 456.49 83655. 1. 920 0.412 0.00 19782. 5.60 456.60 85842. 1. 971 0.428 0.00 19979. 5.62 456.62 86242. 1.980 0.432 0.00 20015. 5.64 456.64 86643. 1. 989 0.437 0.00 20051. 5.66 456.66 87044. 1. 998 0.444 0.00 20087. 5.68 456.68 87446. 2.007 0.453 0.00 20123. 5.70 456.70 87849. 2.017 0 .463 0.00 20159. 5.73 456.73 88454. 2.031 0.475 0.00 20213. 5.75 456.75 88859. 2.040 0.487 0.00 20249. 5.77 456.77 89264. 2.049 0 .496 0.00 20285. 5.90 456.90 91917. 2 .110 0.529 0.00 20521. 6.04 457.04 94808. 2.176 0.558 0.00 20776. 6.17 457.17 97524. 2.239 0.585 0.00 21014. 6.31 457.31 100484. 2.307 0.609 0.00 21272. 6.44 457.44 103265. 2.371 0.633 0.00 21513. 6.58 457.58 106295. 2.440 0.655 0.00 21773. 6.71 457.71 109141. 2.506 0.676 0.00 22016. 6.85 457.85 112242. 2.577 0.697 0.00 22279. 6.90 457.90 113358. 2.602 0.704 0.00 22374. 7.00 458.00 115605. 2.654 1.180 0.00 22563. ··------7.10 458.10 117871. 2.706 2. 040 0.00 22753. 7.20 458.20 120156. 2.758 3.150 0.00 22 944. 7.30 458.30 122460. 2. 811 4.460 0.00 23135. 7.40 458.40 124783. 2.865 5.940 0.00 23327. 7.50 458.50 127125. I 2.918 7.380 0.00 23520. 7.60 458.60 129487. \ 2. 973 7. 920 0.00 23714. 7.70 458.70 131868. 3.027 8.420 0.00 23908. 7.80 458.80 134268. 3. 082 8.900 0.00 24103. 7.90 458.90 136688. 3 .138 9. 34 0 0.00 24299. 8.00 459.00 139128. 3. 194 9.770 0.00 24495. \ I I, \J t <J: ,-16Af 1 o '2--1 o9} G f-''(~l \ ' \__ '\I~' 3d2.-C..f-(o to 8.10 459.10 141587. 3.250 8.20 459.20 144066. 3.307 8.30 459.30 146565. 3.365 8.40 459.40 149084. 3.423 8.50 459.50 151623. 3.481 8.60 459.60 154182. 3.540 8.70 459.70 156761. 3.599 8.80 459.80 159360. 3.658 Hyd Inflow Outflow Peak Target Cale Stage Elev 1 3. 90 ******* 2.21 7.12 458.12 2 1. 94 ******* 0.67 6.69 457.69 3 1. 96 ******* 0.57 6 .11 457.11 4 2.32 ******* 0.51 5.81 456.81 5 2.06 ******* 0 .41 5.47 456.47 6 1. 22 ******* 0.18 4.55 455.55 7 1.59 ******* 0.16 3.83 454.83 8 1. 73 ******* 0.15 3.19 454.19 Route Time Series through Facility Inflow Time Series File:posteast.tsf Outflow Time Series File:eout Inflow/Outflow Analysis Peak Inflow Discharge: 3.90 CFS Peak Outflow Discharge: 2.21 CFS Peak Reservoir Stage: 7 .12 Ft Peak Reservoir Elev: 458.12 Ft at at Peak Reservoir Storage: 118215. Cu-Ft 2. 714 Flow Frequency Analysis Time Series File:eout.tsf Project Location:Sea-Tac Ac-Ft 10.180 o.oo 24692. 10.570 0.00 24890. 10.950 0.00 25089. 11. 310 0.00 25288. 11. 670 0.00 25488. 12.010 0.00 25689. 12.340 0.00 25890. 12.660 0.00 26092. Storage (Cu-Ft) (Ac-Ft) 118215. 2. 714 108789. 2. 497 96232. 2.209 90016. 2.066 83207. 1. 910 65796. 1. 510 53156. 1.220 42664. 0.979 6:00 on Jan 9 in Year 8 10:00 on Jan 9 in Year 8 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.673 2 2/09/01 20:00 2.20 7.11 1 100.00 0.990 0.164 7 12/29/01 10:00 0.673 6.69 2 25.00 0.960 0.505 4 3/06/03 22:00 0. 572 6 .11 3 10.00 0.900 0.148 8 8/26/04 7:00 0.505 5.81 4 5.00 0.800 0.177 6 1/08/05 2:00 0.408 5.47 5 3.00 0.667 0.408 5 1/18/06 23:00 0.177 4.55 6 (2. 00 0.500 0.572 3 11/24/06 8:00 0.164 3.87 7 1.30 0. 231 2.20 1 1/09/08 10:00 0.148 3.19 8 1.10 0 .091 Computed Peaks 1. 69 7.06 50.00 0.980 Flow Duration from Time Series File: eout. tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.010 35422 57.766 57.766 42.234 0.422E+OO 0.029 4693 7.653 65.419 34.581 0.346E+OO 0.047 4818 7.857 73.276 26. 724 0.267E+OO 0.066 4382 7 .146 80.422 19.578 0 .196E+OO 0. 290 0.36E-02 0.29E-02 -18.3 0.36E-02 0.307 0.31E-02 0.28E-02 -9.4 0.31E-02 0.324 0.28E-02 0.26E-02 -5.8 0.28E-02 0.341 0.25E-02 0.24E-02 -2.0 0.25E-02 0.358 0.23E-02 0.22E-02 -4.3 0.23E-02 0.375 0.20E-02 0.18E-02 -5.8 0.20E-02 0.392 0.17E-02 0.15E-02 -12.5 0.17E-02 0.409 0.14E-02 0.12E-02 -15.3 0.14E-02 0.426 0.12E-02 O.lOE-02 -14.7 0.12E-02 0.443 O.lOE-02 0.91E-03 -9.7 O.lOE-02 0 .460 0.90E-03 0. 88E-03 -1. 8 0.90E-03 0.477 0.82E-03 0.80E-03 -2.0 0.82E-03 0. 494 0.62E-03 0.70E-03 13. 2 0.62E-03 0. 511 0.52E-03 0.57E-03 9.4 0.52E-03 0.528 0.39E-03 0.47E-03 20.8 0.39E-03 0.545 0.33E-03 0.42E-03 30.0 0.33E-03 0.562 0.24E-03 0.34E-03 40.0 0.24E-03 0.579 0.20E-03 0.24E-03 25.0 0.20E-03 0.596 0.15E-03 0.23E-03 55.6 0.15E-03 o. 613 0.13E-03 0.18E-03 37.5 0.13E-03 0.630 O.llE-03 O.lSE-03 28.6 0. llE-03 0.648 O.llE-03 0.98E-04 -14.3 O.llE-03 0.665 0.49E-04 0.49E-04 0.0 0.49E-04 0.682 0.33E-04 O.OOE+OO -100.0 0.33E-04 Maximum positive excursion = 0.046 cfs 7. 8%) occuring at 0.590 cfs on the Base Data:preeast.tsf and at 0.636 cfs on the New Data:eout.tsf Maximum negative excursion = 0.096 cfs (-34.3%) occuring at 0.280 cfs on the Base Data:preeast.tsf and at 0.184 cfs on the New Data:eout.tsf Route Time Series through Facility Inflow Time Series File:posteast.tsf Outflow Time Series File:eout Inflow/Outflow Analysis Peak Inflow Discharge: 3.90 CFS at Peak Outflow Discharge: 2.21 Peak Reservoir Stage: 7 .12 Peak Reservoir Elev: 458.12 Peak Reservoir Storage: 118215. 2. 714 Flow Frequency Analysis Time Series File:eout.tsf Project Location:Sea-Tac CFS at Ft Ft cu-Ft Ac-Ft 6:00 10:00 0.290 0.196 -32.4 0.307 0.247 -19.4 0.324 0.307 -5.2 0.341 0.339 -0.6 0.358 0.353 -1. 4 0.375 0.368 -1. 7 0. 392 0.380 -3.0 0.409 0. 394 -3.6 0.426 . 0. 407 -4. 5 0.443 0.428 -3.5 0.460 0.459 -0.2 0.477 0.470 -1. 6 0. 494 0.508 2.8 0.511 0.523 2.3 0.528 0.551 4.2 0.545 0.566 3.7 0.562 0.590 4.9 0.579 0.612 5.7 0.596 0.636 6.6 0.613 0.638 4.0 0.630 0.645 2.4 0.648 0.645 -0.3 0.665 0.667 0.3 0.682 0.670 -1. 7 on Jan 9 in Year 8 on Jan 9 in Year 8 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.673 2 2/09/01 20:00 2.20 7.11 1 100.00 0.990 0.164 7 12/29/01 10:00 0.673 6.69 2 25.00 0.960 0.505 4 3/06/03 22:00 0 .572 6 .11 3 10.00 0.900 0.148 8 8/26/04 7:00 a.sos 5.81 4 5.00 0.800 Actual POND VOLUME CALCULATIONS CORE PROJECT NO. 04009 PROJECT NAME: EVENDELL ELEVATION INCREMENTAL VOLUME TOTAL / VOLUME SF CF CF/ .. / 459.0 27600 ,i:' ·. ' .. , ,'' / . .~, 26,450 / 154,210 25300 .\ ,.·· ' -·_.,. 1 •• 456.0 46,80£ u,100 80,960 ' / 18,600 59,860 ··~ ::, , :· · •. ,, / 29,500 . 450.( . . 12,720 ,': " 4200 · 12,720 . ~ . . ..-: * . ~ --. •" Total Live Storage in Pond . . . ' ( •, 4/f8.0 ** = Total Dead Storage in Pond 4 5 3, 1,4-1 5'0 f r o-...r ·,!.t., [ ;,1 t.-c,k., ~ l ;,a-7 > 2 ~ 6 s ~ f,""' £'L 4, ';; l. fo t;'L 4-'5 g::: i/ t, OfrO C /(.C f'ht,'{!MS. C. Water Quality Volume Calculations Per the Water Quality Applications Map, Basic Water Quality Treatment shall be utilized to mitigate for the developed storm drainage flows. The wet portion of the wetpond and wetvault will satisfy this requirement. The required volume will be designed per KCSWDM Section 6.4.1.1. The following variables were used in the calculation: Volume Factor (f) = 3 Rainfall= 0.039 feet or 0.47 inches Area = developed basin Where Ai= area of impervious surface (sf) A1g = area of till soil covered with grass (sf) Atr = area of till soil covered with forest (sf) A0 = area of outwash soil covered with grass or forest (sf) V, = [0.9Ai + 0.25A1g + O.lA,r+ O.OIA 0 ] * (R/12) Vb= f"Vr WEST BASIN Vb= 3*[(0.9)(1.30) + (0.25)(0.51)]0.039 * (43560sf7ac) = 6,613 CF The dead storage portion of the wetvault is 4.06' deep and has a surface area of 17 feet by 96 feet. The dead storage therefore, has a volume of 6,626 CF which exceeds the required 6,613 CF. A minimum flow path length to width ratio of3:1 is required for the wet portion of the vault. The average width is 17' and the length from inlet to outlet is 199'. The length to width ratio for the vault is therefore, 199' /17' = 11.7: I which exceeds the required minimum 3: I. The sediment storage within the 1st cell was designed with I' of average storage and the sediment storage within the 2nd cell was designed with 0.5' of average storage with bottom slopes within the vault sloping toward the exterior walls. See email on the following pages for allowance to slope the bottom toward the exterior walls rather than towards the center. The average bottom elevation within the 151 cell is (465.44 + 465.59 + 466.29 + 466.44)/4 = 465.94. The top of the sediment storage within the I st cell is elevation 467.02. The average storage depth within the ls' cell is therefore, 467.02- 465.94 = 1.08' which exceeds the required I' average. The average bottom elevation within the 2nd cell (following the Is' cell) is (466.94 + 466.09)/2 = 466.52. The top of the sediment storage within the 2nd cell (following the 1st cell) is elevation 467.02. The average storage depth within the 2nd cell (following the I st cell) is therefore, 467 .02 - 466.52 = 0.5 ', which is equal to the required 0.5' average. The average bottom elevation with the 2nd cell(detention only) is (471.00 + 470.15)/2 = 470.58. The top of the sediment storage within the 2nd cell (detention only) is elevation 471.08. The average storage depth within the 2nd cell is therefore, 471.08 -470.58 = 0.5', which is equal to the required 0.5' average. EAST BASIN 'f he dead storage portion of the wetpond has a volume 7,31 which exceeds the required 34,980 CF. See Pond Volume Calculations sprea sheet in Section 4B of this report. A minimum flow path length to width ratio of3:I is required for the wet portion of the pond. Lengthening of the flow path for the wetpond was accomplished by installing interior berms that extend to the dead storage water surface. The average mid-depth elevation of the 2nd cell of the dead storage is (El. 450 + El. 452.5)/2 = El. 451.25. For simplicity and since it is conservative, the widths along the flow path were measure along El. 451.5 (wider width) instead o f El. 451.25. The width varied through the wetpond but averaged 39'. Measuring of the flow path length was also simplified and conservative. The length was measured beginning within the 2nd cell rather than the average between the two inlets within the I st cell. The length from the beginning of the 2nd cell to the outlet is 257'. The length to width ratio for the pond is therefore, 257' /39' = 6.6: I which exceeds the required minimum 3: I. RE: Evendell Vault Revision Page I of I CORE -Gina Brooks From: Hancock, Dave [Dave.Hancock@METROKC.GOV] Sent: Tuesday, July 20, 2004 7:08 AM To: CORE -Gina Brooks Cc: Walken, Jerry; Wong, Wylie Subject: RE: Evendell Vault Revision Gina, l have discussed your proposed revision to the vault design for the plat of Evendell with staff, and have detennined that sloping the floor towards the exterior walls will not impact our ability to maintain the systemin the future. Sediment removal will be available through the access ports, also located along the exterior of the vault. I would recommend that Wylie document this revision by approving a minor field change, so the revision will not be chal1enged when the project is inspected at later dates. If you need additional assistance please feel free to e-mail me or call me at 206-296-8230. Dave Hancock -----Original Message----- From: CORE -Gina Brooks [mailto:grb@coredesigninc.com] Sent: Monday, July 19, 2004 1:39 PM To: dave.hancock@metrokc.gov Subject: Evendell Dave, I am hoping you can help me document your approval of the vault design for Evendell in regards to the bottom sloping towards the exterior walls rather than the interior. Per Jerry Walken, if I can get approval from maintenance for the sloping of the vault bottom towards the exterior walls then Comment 3 under Title "Sheet C4.32" of the !st Review Comments will become non-applicable. Please reply to this email with your approval so that I may attach this email to my response letter for Wylie Wong's review. '!banks for your help. Gina R. Brooks, P.E. Core Design, Inc. 14711 NE 29th Place, Suite IOI Bellevue, WA 98007 425-885-7877 425-885-7963 (fax) 7/20/2004 KING COUNTY WATER QUALITY APPLICATIONS MAP EVENDELL CORE PROJECT NO. 04009 Co;;;;-uton tlBa 'ff." ::1. N I R ____ _ 0 wout.dur + wtarget.du r x o+.no.JL_ ________ _:...:ii.-------------------- 0- 0 * 0 ~ ~:+---------------4:----------------- (J') <O LL u '-' 0 00 0 Probability Exceedence 0·--t--""---,----,--,-r,-,n-r,,----,-,--,---,rrrTT""---.----.-.--,rri-rn.-------,-.---T-,-,r-,-,--,-,--~---.-..,.!-,~~ 1 0-'I VAULT FREQUENCY/ DURATION COMPARISON EVENDELL CORE PROJECT NO. 04009 1 EAST BASIN The East Basin will utilize a wetpond to accommodate the required Level 2 Flow Control. The East Basin wetpond will receive runoff from the upstream tributary area as well as runoff from onsite. The upstream tributary area will be routed through the onsite storm drainage system to the wetpond. The allowable release rates will be established by the sum of the upstream tributary runoff plus the existing onsite runoff. The allowable release rate will be delineated as preeast.tsf and will be the sum of exeast.tsf + upsteast.tsf. The flows entering the wetpond will be the sum of the upstream tributary area and the developed site going to the pond. The total developed flows discharging to the pond will be delineated as posteast.tsf and will be the sum of deveast.tsf and upsteast.tsf. The East Basin wetpond ( epond.rdf) was sized based on the 1998 KCSWDM and KCRTS Computer Software Reference Manual. See attached KCRTS printouts and attached pond volume calculation spreadsheet on the following pages. The stage-storage of the pond produced by KCRTS was utilized to calculate storage values at the elevations used to calculate the proposed wetpond that will actually be constructed onsite. The KCRTS interpolated storage values are listed below. Elevation sf Length x Width KCRTS Storage KCRTS Storage* I 0% Safetv Factor 451 "lt,t. 225' X 43' 0 0 452 II 7 ?,O 230' X 5]' 11,265 CF 12,391 CF 454 I<;" 04,, 235' X 64' 39,600 CF 39,600 CF 456 1~04-o 238' X 80' 73,986 CF 81,384 CF 458 ., -~--240' X 85' 115,605 CF 127,165 CF Per the proposed Pond Volume Calculations spreadsheet on the following pages, the storage values at each delineated elevation is more than the required 10% safety factor storage values calculated above. The pond is therefore, adequately sized to accommodate the required I 0% safety factor. Flow Frequency Analysis Time Series File:preeast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.698 2 2/09/01 18:00 0.999 1 100.00 0.990 0.238 7 1/05/02 16:00 0.698 2 25.00 0. 960 0.580 3 2/28/03 3:00 0.580 3 10.00 0.900 0.060 8 8/26/04 2:00 0.559 4 5.00 0.800 0.339 6 1/05/05 8:00 0.516 5 3.00 0.667 0.559 4 1/18/06 20:00 0.339 6 2.00 0.500 0.516 5 11/24/06 4:00 0.238 7 1. 30 0.231 0.999 1 1/09/08 9:00 0.060 8 1.10 0. 091 Computed Peaks 0.899 50.00 0.980 Flow Frequency Analysis Time Series File:posteast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 1. 94 6 2/09/01 2,00 1.59 8 1/05/02 16,00 2.32 3 2/27/03 7,00 1. 73 7 8/26/04 2,00 2.08 4 10/28/04 16,00 2.06 5 1/18/06 16,00 2.52 2 10/26/06 o,oo 3.90 1 1/09/08 6,00 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 3.90 1 100.00 0.990 2.52 2 25.00 0. 960 2.32 3 10.00 0.900 2.08 4 5.00 0.800 2.06 5 3.00 0.667 1.94 6 2.00 0.500 1. 73 7 1. 30 0.231 1. 59 8 1.10 0.091 3.44 50.00 0.980 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: Detention Pond 3.00 H:lV 165.00 ft / 67 .00 ft / 11055. sq. ft 24299. sq. ft 0.558 acres 6. 90 ft 451.00 ft 113358. cu. ft 2.602 ac-ft 6. 90 ft 18.00 inches 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1. 75 0.160 2 4.70 3.00 0.362 6.0 3 5.60 2.00 0.124 4.0 Top Notch Weir: None ..-- Outflow Rating Curve: None Q, bl\-b l{-7 Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cf s) 0.00 451.00 o. 0.000 0.000 0.00 0.02 451. 02 221. 0.005 0. 011 0.00 0.04 451.04 443. 0.010 0.016 0.00 0.05 451. 05 555. 0. 013 0.019 0.00 0.07 451. 07 777. 0.018 0.022 0.00 0.09 451. 09 1001. 0.023 0.025 0.00 0 .11 451.11 1225. 0.028 0.027 0.00 0 .13 451.13 1449. 0.033 0.030 0.00 0.15 451.15 1674. 0. 038 0.032 0.00 0.28 451. 28 3150. 0. 072 O·. 044 0.00 0.42 451. 42 4767. 0.109 0.054 0.00 0.55 451.55 6293. 0.144 0.062 0.00 0.69 451. 69 7963. 0.183 0.069 0.00 0.82 451. 82 9540. 0.219 0.075 0.00 0.96 451. 96 1i 11265/ 0.259 0.081 0.00 1.09 452.09 11'0 12892: 0 .296 0.087 0.00 1. 23 452.23 14673. 0.337 0.092 0.00 1.36 452.36 16352. 0.375 0.097 0.00 1.50 452.50 18189. 0. 418 0.102 0.00 1. 63 452.63 19921. 0.457 0.106 0.00 1. 77 452.77 21814. 0.501 0 .110 0.00 1.90 452.90 23599. 0.542 0 .115 0.00 2.04 453.04 25551. 0.587 o .119 0.00 2.18 453.18 27532. 0.632 0.123 0.00 2.31 453.31 29399. 0.675 0.126 0.00 2.45 453.45 31439. 0. 722 0 .130 0.00 2.58 453.58 33361. 0.766 0.133 0.00 Surf Area (sq. ft) 11055. 11083. 11111. 11125. 11153. 11181. 11209. 11237. 11265. 11448. 11646. 11831. 12033. 12221. 12424. 12615. 12822. 13015. 13224. 13420. 13632. 13830. 14044. 14261. 14463. 14681. 14886. 8.10 459.10 141587. 3.250 10.180 0.00 24692. 8.20 459.20 144066. 3.307 10.570 0.00 24890. 8.30 459.30 146565. 3.365 10.950 0.00 25089. 8.40 459.40 149084. 3.423 11.310 0.00 25288. 8.50 459.50 151623. 3.481 11. 670 0.00 25488. 8.60 459.60 154182. 3.540 12.010 0.00 25689. 8.70 459.70 156761. 3.599 12.340 0.00 25890. 8.80 459.80 159360. 3.658 12.660 0.00 26092. Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft) 1 3.90 ******* 2.21 7.12 458.12 118215. 2.714 2 1. 94 ******* 0.67 6.69 457.69 108789. 2 .497 3 1. 96 ******* 0.57 6.11 457 .11 96232. 2.209 4 2.32 ******* 0.51 5.81 456.81 90016. 2.066 5 2.06 ******* 0.41 5.47 456.47 83207. 1. 910 6 1.22 ******* 0.18 4.55 455.55 65796. 1. 510 7 1. 59 ******* 0.16 3.83 454.83 53156. 1. 220 8 1. 73 ******* 0.15 3.19 454.19 42664. 0.979 ---------------------------------- Route Time Series through Facility Inflow Time Series File,posteast.tsf Outflow Time Series File:eout Inflow/Outflow Analysis Peak Inflow Discharge: 3.90 CFS at 6,00 on Jan 9 in Year 8 Peak Outflow Discharge, 2.21 CFS at 10,00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.12 Ft Peak Reservoir Elev: 458.12 Ft Peak Reservoir Storage, 118215. Cu-Ft 2.714 Ac-Ft Flow Frequency Analysis Time Series File:eout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.673 2 2/09/01 20,00 0.164 7 12/29/01 10,00 0.505 4 3/06/03 22,00 0.148 8 8/26/04 7,00 0.177 6 1/08/05 2,00 0 .408 5 1/18/06 23,00 0.572 3 11/24/06 8,00 2.20 1 1/09/08 10,00 Computed Peaks -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft) Period 2.20 7 .11 1 100.00 0.990 0.673 6.69 2 25.00 0.960 0 .572 6 .11 3 10.00 0.900 0.505 5.81 4 5.00 0.800 0 .408 5.47 5 3.00 0.667 0.177 4.55 6 ~2. 00 0.500 0.164 3.87 7 1. 30 0.231 0.148 3.19 8 1.10 0.091 1. 69 7.06 50.00 0.980 Flow Duration from Time Series File, eout. tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.010 35422 57.766 57.766 42.234 0.422E+OO 0.029 4693 7.653 65.419 34.581 0.346E+OO 0.047 4818 7.857 73.276 26.724 0.267E+OO 0.066 4382 7.146 80.422 19.578 0.196E+OO 0.085 3756 6.125 86.548 13.452 0.135E+OO 0.104 2974 4.850 91. 3 98 8.602 0.860E-Ol 0.123 1842 3.004 94.401 5.598 0.560E-01 0 .142 1431 2.334 96.735 3.265 0.326E-Ol 0.161 979 l. 597 98.332 1.668 0.167E-Ol 0.180 740 l. 207 99.538 0.462 0.462E-02 0.199 41 0.067 99.605 0.395 0.395E-02 0.218 15 0.024 99.630 0.370 0.370E-02 0.237 16 0.026 99.656 0.344 0.344E-02 0.256 10 0.016 99. 672 0.328 0.328E-02 0.275 8 o. 013 99.685 0.315 0.315E-02 0.294 7 0. Oll 99.697 0.303 0.303E-02 0 .313 18 0.029 99.726 0.274 0.274E-02 0.332 11 0.018 99.744 0.256 0.256E-02 0.350 14 0.023 99.767 0.233 0.233E-02 0.369 25 0.041 99.808 0.192 0.192E-02 0.388 23 0.038 99.845 0.155 0.155E-02 0 .407 22 0.036 99.881 0. ll9 0. ll9E-02 0.426 9 0.015 99.896 0 .104 0.104E-02 0.445 8 0.013 99.909 0.091 O. 913E-03 0. 464 4 0.007 99. 915 0.085 0. 848E-03 0. 483 5 0.008 99. 923 0.077 0.766E-03 0.502 6 0.010 99.933 0.067 0.669E-03 0.521 8 0. 013 99.946 0.054 0.538E-03 0.540 7 0. Oll 99.958 0.042 0.424E-03 0 .559 5 0.008 99.966 0.034 0. 342E-03 0.578 5 0.008 99.974 0.026 0.261E-03 0.597 2 0.003 99.977 0.023 0.228E-03 0.616 3 0.005 99.982 0.018 0.179E-03 0.635 2 0. 003 99.985 0.015 0.147E-03 0.653 4 0.007 99.992 0.008 0.815E-04 0.672 4 0.007 99.998 0.002 0.163E-04 Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft) l 3.90 ******* 2.21 7.12 458.12 ll8215. 2. 714 2 l. 94 ******* 0.67 6.69 457.69 108789. 2.497 3 l. 96 ******* 0.57 6 .11 457. ll 96232. 2.209 4 2.32 ******* 0.51 5.81 456.81 90016. 2.066 5 2.06 ******* 0. 41 5.47 456.47 83207. 1.910 6 l. 22 ******* 0.18 4.55 455.55 65796. l. 510 7 1.59 ******* 0.16 3.87 454.87 53987. l. 239 8 l. 73 ******* 0.15 3.19 454.19 42664. 0.979 Duration Comparison Anaylsis Base File: preeast.tsf New File: eout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.170 0.82E-02 0.82E-02 -0.8 I 0.82E-02 0.170 0.170 -0.l 0.187 0.70E-02 0.37E-02 -47.l I 0.70E-02 0.187 0.173 -7.6 0.204 0.62E-02 0.35E-02 -44.l I 0.62E-02 0.204 0.175 -14 .4 0.222 0.55E-02 0.33E-02 -39.4 I 0.55E-02 0.222 0.176 -20.5 0.239 0.50E-02 0.31E-02 -36.9 I 0.50E-02 0.239 0.177 -25.8 0.256 0.45E-02 0.30E-02 -32.7 I 0.45E-02 0.256 0.178 -30.3 0.273 0.40E-02 0.30E-02 -25.4 I 0.40E-02 0.273 0.181 -33.7 0.290 0.36E-02 0.29E-02 -18.3 0.36E-02 0.307 0.31E-02 0.28E-02 -9.4 0.31E-02 0.324 0.28E-02 0.26E-02 -5.8 0.28E-02 0.341 0.25E-02 0.24E-02 -2.0 0.25E-02 0.358 0.23E-02 0.22E-02 -4.3 0.23E-02 0.375 0.20E-02 0.18E-02 -5.8 0.20E-02 0. 392 0.17E-02 0.15E-02 -12.5 0.17E-02 0.409 0.14E-02 0.12E-02 -15.3 0 .14E-02 0.426 0.12E-02 O.lOE-02 -14.7 0.12E-02 0.443 O.lOE-02 0.91E-03 -9.7 O.lOE-02 0.460 0.90E-03 0.88E-03 -1. 8 0.90E-03 0.477 0.82E-03 O.BOE-03 -2.0 0. 82E-03 0. 494 0.62E-03 0.70E-03 13.2 0.62E-03 0.511 0.52E-03 0.57E-03 9.4 0.52E-03 0.528 0.39E-03 0.47E-03 20.8 0.39E-03 0.545 0.33E-03 0.42E-03 30.0 0.33E-03 0.562 0.24E-03 0.34E-03 40.0 0.24E-03 0.579 0.20E-03 0.24E-03 25.0 0.20E-03 0.596 0.15E-03 0.23E-03 55.6 0.15E-03 0.613 0.13E-03 0.18E-03 37.5 0.13E-03 0.630 O.llE-03 0.15E-03 28.6 O.llE-03 0.648 O.llE-03 0.98E-04 -14.3 O.llE-03 0.665 0.49E-04 0.49E-04 0.0 0.49E-04 0.682 0.33E-04 O.OOE+OO -100.0 0.33E-04 Maximum positive excursion = 0.046 cfs ( 7. 8%) occuring at 0.590 cfs on the Base Data:preeast.tsf and at 0.636 cfs on the New Data:eout.tsf Maximum negative excursion = 0 .096 cfs (-34.3%) occuring at 0.280 cfs on the Base Data,preeast.tsf and at 0.184 cfs on the New Data:eout.tsf ---------------------------------- Route Time Series through Facility Inflow Time Series File:posteast.tsf Outflow Time Series File:eout Inflow/Outflow Analysis Peak Inflow Discharge: 3.90 Peak Outflow Discharge, 2.21 Peak Reservoir Stage, 7 .12 Peak Reservoir Elev: 458.12 Peak Reservoir Storage: 118215. 2. 714 Flow Frequency Analysis Time Series File:eout.tsf Project Location:Sea-Tac CFS at CFS at Ft Ft cu-Ft Ac-Ft 6,00 10,00 0.290 0.196 -32.4 0.307 0.247 -19.4 0.324 0.307 -5.2 0.341 0.339 -0.6 0.358 0.353 -1. 4 0.375 0.368 -1. 7 0. 392 0. 380 -3. 0 0.409 0. 394 -3.6 0.426 0.407 -4. 5 0.443 0.428 -3.5 0. 460 0.459 -0.2 0 .477 0.470 -1. 6 0.494 0.508 2.8 0. 511 0.523 2.3 0.528 0.551 4.2 0.545 0.566 3.7 0.562 0.590 4.9 0.579 0.612 5.7 0.596 0.636 6.6 0.613 0.638 4.0 0.630 0.645 2.4 0.648 0.645 -0.3 0.665 0.667 0.3 0.682 0.670 -1. 7 on Jan 9 in Year 8 on Jan 9 in Year 8 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of (CFS) 0.673 2 2/09/01 0.164 7 12/29/01 0.505 4 3/06/03 0.148 8 8/26/04 Peak 20,00 10,00 22,00 7,00 --Peaks --Rank Return Prob (CFS) (ft) Period 2.20 7.11 1 100.00 0.990 0.673 0.572 0.505 6.69 6 .11 5.81 2 3 4 25.00 10.00 5.00 0. 960 0.900 0.800 0.177 6 1/08/05 2:00 0.408 5.47 5 3.00 0.667 0.408 5 1/18/06 23:00 0.177 4.55 6 2.00 0.500 0.572 3 11/24/06 8:00 0.164 3.87 7 1. 30 0.231 2.20 1 1/09/08 10:00 0 .148 3.19 8 1.10 0.091 Computed Peaks 1. 69 7.06 50.00 0.980 Flow Duration from Time Series File:eout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.010 35422 57.766 57.766 42.234 0.422E+OO 0.029 4693 7.653 65.419 34.581 0.346E+OO 0.047 4818 7.857 73.276 26.724 0.267E+OO 0.066 4382 7 .146 80.422 19.578 0 .196E+OO 0.085 3756 6.125 86.548 13.452 0 .135E+OO 0.104 2974 4.850 91.398 8.602 0.860E-01 0.123 1842 3.004 94. 401 5.598 0.560E-01 0.142 1431 2.334 96. 735 3.265 0.326E-01 0.161 979 1.597 98.332 1.668 0.167E-Ol 0.180 740 1. 207 99.538 0.462 0.462E-02 0.199 41 0.067 99.605 0.395 0.395E-02 0.218 15 0.024 99.630 0.370 0.370E-02 0.237 16 0.026 99.656 0.344 0.344E-02 0.256 10 0.016 99.672 0.328 0.328E-02 0.275 8 0.013 99.685 0.315 0.315E-02 0.294 7 0. 011 99.697 0.303 0.303E-02 0 .313 18 0.029 99.726 0.274 0.274E-02 0.332 11 0.018 99.744 0.256 0.256E-02 0.350 14 0.023 99.767 0.233 0.233E-02 0.369 25 0.041 99.808 0.192 0.192E-02 0.388 23 0.038 99.845 0.155 0.155E-02 0.407 22 0.036 99.881 0 .119 0 .119E-02 0.426 9 0.015 99.896 0.104 0.104E-02 0.445 8 0.013 99.909 0.091 0. 913E-03 0.464 4 0.007 99. 915 0.085 0.848E-03 0. 483 5 0.008 99.923 0.077 0.766E-03 0.502 6 0.010 99.933 0;067 0.669E-03 0.521 8 0.013 99.946 0.054 0.538E-03 0.540 7 0. 011 99.958 0.042 0.424E-03 0.559 5 0.008 99.966 0.034 0.342E-03 0.578 5 0.008 99.974 0.026 0.261E-03 0.597 2 0.003 99.977 0.023 0.228E-03 0.616 3 0.005 99.982 0.018 0.179E-03 0.635 2 0.003 99.985 0.015 0.147E-03 0.653 4 0.007 99. 992 0.008 0.815E-04 0. 672 4 0.007 99.998 0.002 0.163E-04 "-----eout.dur + etarget.du r x 0 <.D 0 L{") "'1-+-----------~r------------------0 ooo ____ _ 0 M...l----------------','1---,---------------,..-,. . v,O LL.. u '--' <l> 'J) L 00 -----o~_j ___________________ _c.=..,,..,.. ________ _ L_- <..)Q ({) 0 POND FREQUENCY/ DURATION COMPARISON EVENDELL CORE PROJECT NO. 04009 1 East Basin Wetond Overflow Elevations The primary overflow for the pond is the riser pipe within the control structure. The water surface elevation above the riser for the 100 year developed flow is calculated assuming all orifices are plugged. To pass the 100-year return period storm, 3.90 cfs, through a 18" overflow riser will require 0.47 feet of head (From Figure 5.3.4.H in the 1998 KCSWDM: Qweir = 9.739DH 312 => 3.90 = 9.739(15/12)H312 => H = 0.41 feet). The primary overflow elevation would therefore, be equal to the elevation of the top of the riser plus the amount of head required to pass the I 00-year return period storm, Elev. 458.00 + 0.41 feet= Elev. 458.41. The secondary overflow for the pond is the jailhouse weir located on the control structure catch basin. To pass the 100-year return period storm at 0.41 feet of head, a minimum 4.60-foot wide jailhouse weir will be required. The jailhouse weir is analyzed as a notch weir using the following equation: Q = C (L-0.2H)H312 where Q = flow (3.90 cfs) C = 3.27 + 0.40 HIP H = head above weir (0.41 ft<= Use Same Head as Req'd Head Over Riser) P = depth of storage at weir (Elev. 458.0-Elev. 450.0 = 8.0 feet) L = length of the riser (ft) An emergency overflow spillway will be installed and constructed also as a 12-foot wide access road to the control structure. The emergency overflow/access road will be surfaced with asphalt. The emergency overflow spillway will be located at the primary and secondary overflow elevation 458.41. The 12' wide spillway can accommodate the 100-year return period flow of3.90 cfs at a head of0.2'. Qioo = C (2g)112 [(2/3)LH312 + (8/15)(Tan 8)H 512 ] where Q 1oo = peak flow (3.90 cfs) C=0.6 G = 32.2 ft/sec 2 H = head above weir L = length of weir (12 ft) fl= angle of side slopes (Tan fl= 10) 3.90= 0.6 (2*32.2)112 [(2/3)(12)(H)31 2 + (8/15)(10)(H)512 ] H=0.2' C. Water Quality Volume Calculations Per the Water Quality Applications Map, Basic Water Quality Treatment shall be utilized to mitigate for the developed storm drainage flows. The wet portion of the wetpond and wetvault will satisfy this requirement. The required volume will be designed per KCSWDM Section 6.4.1.1. The following variables were used in the calculation: Volume Factor (f) = 3 Rainfall= 0.039 feet or 0.47 inches Area = developed basin Where Ai= area of impervious surface (sf) A1g = area of till soil covered with grass (sf) A,r = area of till soil covered with forest (sf) A0 = area of outwash soil covered with grass or forest (sf) V, = [0.9Ai + 0.25A,g + O.lA,r + O.OlA 0 ] * (R/12) Vb= fl'Vr WEST BASIN Vb= 3*[(0.9)(1.30) + (0.25)(0.51)]0.039 * (43560sf/ac) = 6,613 CF The dead storage portion of the wetvault is 4.06' deep and has a surface area of 17 feet by 96 feet. The dead storage therefore, has a volume of 6,626 CF which exceeds the required 6,613 CF. A minimum flow path length·to width ratio of3:l is required for the wet portion of the vault. The average width is 17' and the length from inlet to outlet is 199'. The length to width ratio for the vault is therefore, 199 '/17' = 11. 7: 1 which exceeds the required minimum 3:1. The sediment storage within the I st cell was designed with I' of average storage and the sediment storage within the 2nd cell was designed with 0.5' of average storage with bottom slopes within the vault sloping toward the exterior walls. See email on the following pages for allowance to slope the bottom toward the exterior walls rather than towards the center. The average bottom elevation within the 151 cell is (465.44 + 465.59 + 466.29 + 466.44)/4 = 465.94. The top of the sediment storage within the 1" cell is elevation 467.02. The average storage depth within the I'' cell is therefore, 467.02- 465.94 = 1.08' which exceeds the required l' average. The average bottom elevation within the 2nd cell (following the 1'1 cell) is (466.94 + 466.09)/2 = 466.52. The top of the sediment storage within the 2nd cell (following the I st cell) is elevation 467.02. The average storage depth within the 2nd cell (following the I st cell) is therefore, 467 .02 - 466.52 = 0.5', which is equal to the required 0.5' average. The average bottom elevation with the 2nd cell(detention only) is (471.00 + 470.15)/2 = 470.58. The top of the sediment storage within the 2nd cell (detention only) is elevation 471.08. The average storage depth within the 2nd cell is therefore, 471.08-470.58 = 0.5', which is equal to the required 0.5' average. EAST BASIN ...--1 The dead storage portion of the wetpond has a volume 7,311 which exceeds the · required 34,980 CF. See Pond Volume Calculations sprea sheet in Section 4B of this report. A minimum flow path length to width ratio of3:l is required for the wet portion of the pond. Lengthening of the flow path for the wetpond was accomplished by installing interior berms that extend to the dead storage water surface. The average mid-depth elevation of the 2nd cell of the dead storage is (El. 450 + El. 452.5)/2 = El. 451.25. For simplicity and since it is conservative, the widths along the flow path were measure along El. 451.5 (wider width) instead o f El. 451.25. The width varied through the wetpond but averaged 39'. Measuring of the flow path length was also simplified and conservative. The length was measured beginning within the 2nd cell rather than the average between the two inlets within the 1" cell. The length from the beginning of the 2nd cell to the outlet is 257'. The length to width ratio for the pond is therefore, 257' /39' = 6.6: 1 which exceeds the required minimum 3: 1. / r, I I/ flt t Bo, i:i I-. . . Af.·~J:,S.9°, ~-;J- I ~-. I ltimrrfl: KING COUNTY WATER QUALITY APPLICATIONS MAP EVENDELL rli,tilil'cll't '<L' l~r:~ CORE PROJECT NO. 04009 6.4.1 WETPONDS -BASIC AND LARGE-MFTHODS OF ANALYSIS FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES (FEEn 0 .54 • (0.045') c~ Incorporated Area -c::::i River/Lake Major Road 0.47' (0.039') 0.47· (0.039') NOTE: Areas east of the easternmost isopluvial should use 0.65 inches unless rainfall data is available for the location of interest 2" The mean annual storm is a conceptual storm found by dividing the annual precipilation by the total number of storm events per year ST LA co i, l~z b,..-,,..'..b., / .--_3--... w~ <r-T-_,t ..,~ ( 0. 04 7') LA 1.0 LA 1.2 0 . 9 ••••••••• '°""" Q result, generates large.amounts of runoff. For this application, till soil types include Buckley and bedrock soils, and alluvial and outwash soils that have a seasonally high water table or are underlain at a shallow depth (less than 5 feet) by glacial till. U.S. Soil Conservation Service (SCS) hydrologic soil groups that are classified as till soils include a few B, most C, and all D soils. See Chapter 3 for classification of specific SCS soil types. 1998 Surface Water Design Manual 9/1/98 ,6-69 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN: ON-SITE DRAINAGE SYSTEM The conveyance system for the site was designed for both the 25-year, 24-hour storm and the I 00-year, 24-hour storm. A backwater analysis sheet was generated for both the 25- year and I 00-year return period storms. Total flows from each basin and upstream tributary area using 15-minute time steps were calculated. The inputs to calculate the total flows were the same for the West Basin and Upstream Tributary Area (See Section 4 of this report) but, varied for the East Basin. The total flows calculated for the East Basin excludes the Stonn and Recreational Tracts (Tracts L & M) since these areas do not enter the conveyance system. The inputs used for the KCRTS analysis for the East Basin is summarized in the table below: REVISED EAST BASIN Total Area= 8.94 acres DEVELOPED CONDITIONS (<least! 5) GROUND COVER AREA(acre) Till-Grass (Landscaoing) 2.25 hnpervious 6.69 The West Basin flow frequency analysis is attached as dwest15.tsf. The total KCRTS 25- year return period flow and the!OO-year return period flow for the West Basin are 1.28 cfs and I. 79 cfs consecutively. The East Basin flow frequency analysis is attached as deast15.tsf. The East Basin Upstream Tributary flow frequency analysis is attached as upeastl 5.tsf. And the combination of both time series for onsite and upstream areas for the East Basin is attached as poste15.tsf. The total KCRTS 25-year return period flow and the I 00-year return period flow for the East Basin are 6.54 cfs and 9.06 cfs consecutively. For simplicity, large basin areas going to multiple catch basins were used. For the West Basin, it was simply assumed that the total flows for the entire basin enter all drainage pipe. Flows for the large areas within the East Basin were simply calculated as a portion of the overall 15-minute flows based on the area ratio. There will be four large basins delineated for the East Basin. See Catch Basin Subbasin Map on the following pages. The flows for each subbasin is calculated below. Subbasin Subbasin Percent 25-year Percent 100-year Return Area Area/East Basin Return Period Period Flow Flow Basin A 0.51 AC 0.51/8.94 = 5.70%*6.54 = 5.70%*9.06 = 0.52 cfs 5.70% 0.37 cfs Basin B 0.80AC 0.80/8.94 = 8.95%*6.54 = 8.95%*9.06 = 0.81 cfs 8.95% 0.59 cfs Basin C 3.87 AC 3.87/8.94 = 43.29%*6.54 = 43.29%*9.06 = 3.92 cfs 43.29% 2.83 cfs Basin D 3.76 AC 3.76/8.94 = 42.06%*6.54 =, 5.70%*9.06 = 3.81 cfs 42.06% 2.75 cfs Total 8.94AC 8.94/8.94 = 6.54 cfs 9.06 cfs 100% The tailwater elevations within the wetpond and wetvault were derived from the KCRTS outfall information (wout.tsf and eout.tsf). The tailwater elevations within the wetvault for the 25-year and 100-year return periods are El. 477.62 and El. 478.50 consecutively. The tailwater elevations within the wetpond for the 25-year and 100-year return periods are El. 457 .69 and El. 458.11 consecutively. The backwater analysis was performed to ensure that during the 25-year design storm, the maximum water surface elevation in each structure did not exceed an elevation equal to 0.5' less the rim and during the 100-year design storm, ensuring that if the maximum water surface elevation does exceed the rim, topography of the basin would allow the overflow to be conveyed to the next downstream catch basin or the topography would allow for ponding without causing structural damage. During the 25-year, the headwater elevations do not exceed 0.5' less the rim. During the 100-year, the headwater elevations exceed CB 3 and CB 31 rims. Overflow over CB 3 will simply drain to the next downstream catch basin. Drainage overflowing CB 31 will pond and overflow the crown of the road before jumping the curb and flow to the next downstream catch basin. BACKWATER CAl.ctn.ATIONS OBNA.'1:E: EVEl'\'DELL PREPARED BY: G.Bn,ob OB NUMBER: 04009 DESIG:'li STORM: 25 YEAR ENTRANCE ENTRANCE EXIT OUTLET INLET APPROACH BEND JUNCTION PIPE PIPE MANNING'S OUTLET U.'LET PIPE FLOW VELOCITY TAILWATER FRICTION HGL HEAD HEAD CONTROL CONTROL VELOCITY HEAD HEAD HEADWATER FROM TO FLOW LENGTH DIA. • ELEVATION ELEVATION AREA VELOCITY HEAD ELEVATION LOSS ELEVATIOS LOSS LOSS ELEVATIO N ELEVATION HEAD LOSS LOSS ELEVATION CB CB (CFS\ (FEET) =, VALUE (FEET) ~n ,=m <FrlSEC) (FEET) (FEET) (FEEn =•n (FEET) (FEET) (FEET) =•n <FFF.T) (FEET) <FEETI (FEETI RIMEL ,. 4 0.37 206 12 0.012 454.07 455.10 0.79 0.47 0.00 45&.57 O.D2 458.59 0.00 0.00 458.59 456.10 0.00 0.00 0.00 458.59 462.00 4 3 0.37 80 12 0.012 455.10 456.30 0.79 0.47 0.00 458.59 0.01 458.60 0.00 0.00 458.60 457.30 0.00 0.00 0.00 458.60 459.30 5A 5 6.17 " 18 0.012 448.50 453.01 1.77 3.49 0.19 457.69 0.17 457.86 0.09 0.19 458.14 454.51 0.12 0.17 0.09 458.28 463.41 5 58 3.42 90 15 0.012 453.34 456.00 1.23 2.79 0.12 458.28 0.21 458.50 0.06 0.12 458.68 457.25 0.12 0.00 O.Dl 458.57 465.56 5 6 2.75 50 12 0.012 453.51 459.42 0.79 3.50 0.19 458.28 0.25 460.42 0.10 0.19 460.71 460.52 0.19 0.25 0.00 460.77 463.15 6 7 2.75 24 12 0.012 459.42 459.66 0.79 3.50 0.19 4fiJ.77 0.12 460.89 0.10 0.19 461.17 460.81 0.19 0.25 0.00 461.23 463.15 7 8 2.75 44 12 0.012 459.66 459.88 0.79 3.50 0.19 461.23 0.22 461.46 0.10 0.19 461.74 461.04 0.19 0.10 0.00 461.65 463.36 8 9 2.75 142 12 0.012 459.88 462.15 0.79 3.50 0.19 461.65 0.71 463.15 0.10 0.19 463.44 463.30 0.19 0.01 0.11 463.36 466.16 9 10 2.75 26 12 0.012 462.15 462.83 0.79 3.50 0.19 463.36 0.13 463.83 0.10 0.19 464.12 463.97 0.00 0.00 0.00 464.12 466.33 9 II 2.75 102 12 0.012 462.15 464.50 0.79 3.50 0.19 463.36 0.51 465.50 0.10 0.19 465.79 465.65 0.19 0.18 0.11 465.88 468.23 II 12 2.75 16 12 0.012 464.50 464.66 0.79 3.50 0.19 465.88 0.08 465.96 0.10 0.19 466.24 465.81 0.00 0.00 0.00 466.24 468.73 II 13 2.75 53 12 0.012 464.50 465.56 0.79 3.50 0.19 465.88 0.27 466.56 0.10 0.19 466.85 466.71 0.19 0.22 0.00 466.88 469.30 13 14 2.75 24 12 0.012 465.56 465.80 0.79 3.50 0.19 466.88 0.12 467.00 0.10 0.19 467.28 466.95 0.19 0.25 0.00 467.34 469.30 14 15 2.75 183 12 0.012 465.80 471.29 0.79 3.50 0.19 467.34 0.92 472.29 0.10 0.19 472.58 472.43 0.19 0.14 0.00 472.53 474.76 15 16 2.75 26 12 0.012 471.29 471.55 0.79 3.50 0.19 472.53 0.13 472.66 0.10 0.19 472.95 472.70 0.00 0.00 0.00 472.95 475.08 58 17 3.42 32 15 0.012 456.00 462.98 1.23 2.79 0.12 458.28 0.08 464.23 0.06 0.12 464.41 46423 0.12 0.00 0.07 464.36 466.76 17 18 3.42 24 12 0.012 463.23 463.47 0.79 4.35 0.29 464.36 0.19 464.55 0.15 0.29 464.99 464.89 0.29 0.00 0.00 464.69 466.76 18 19 3.42 II 12 0.012 463.47 463.80 0.79 4.35 0.29 464.69 0.09 464.80 0.15 0.29 465.24 465.21 0.00 0.00 0.00 465.24 467.39 17 20 3.42 73 15 0.012 462.98 465.46 l.23 2.79 0.12 464.36 0.17 466.71 0.06 0.12 466.89 466.71 0.29 0.02 0.07 466.68 469.42 20 21 3.42 24 12 0.012 465.71 465.95 0.79 4.35 0.29 466.68 0.19 466.9S 0.1S 0.29 467.39 467.37 0.00 0.00 0.00 467.39 469.42 20 22 3.42 81 12 0.012 465.71 468.71 0.79 4.35 0.29 466.68 0.63 469.71 0.15 0.29 470.15 470.12 0.29 0.07 0.00 469.93 472.24 22 23 3.42 90 12 0.012 468.71 471.05 0.79 4.35 029 469.93 0.70 472.05 0.15 0.29 472.49 472.46 0.29 0.05 0.16 472.41 474.57 23 24 3.42 24 12 0.012 471.05 471.53 0.79 4.35 0.29 472.41 0.19 472.60 0.15 0.29 473.04 472.94 0.00 0.00 0.00 473.04 474.55 23 25 3.42 21 12 0.012 471.05 471.68 0.79 4.35 0.29 472.41 0.16 472.68 0.15 0.29 473.12 473.09 0.29 0.02 0.16 473.01 475.22 25 26 3.42 24 12 0.012 471.68 471.92 0.79 4.35 0.29 473.0I 0.19 473.19 0.1S 0.29 473.64 473.34 0.00 0.00 0.00 473.64 475.43 25 27 3.42 99 12 0.012 471.68 474.16 0.79 4.35 029 473.01 0.77 475.16 0.15 0.29 475.60 475.57 0.00 0.00 0.00 475.60 477.66 23 " 3.42 112 12 0.0]2 471.05 472.73 0.79 4.35 029 472.41 0.87 473.73 0.15 0.29 474.17 474.15 0.29 0.00 0.00 473.88 476.55 28 29 3.42 142 12 0.012 472.73 474.14 0.79 4.35 0.29 473.88 I.IQ 475.14 0.15 0.29 475.58 475.56 0.29 0.06 0.00 475.3."'i 479.07 29 30 3.42 28 12 0.012 474.14 474.28 0.79 4.35 0.29 475.35 0.22 475.56 0.15 0.29 476.0J 475.70 0.01 0.17 035 476.52 479.22 30 31 3.42 29 12 0.012 475.66 476.24 0.79 4.35 029 476.52 0.23 477.24 0.15 0.29 477.68 477.65 0.00 0.00 0.00 477.68 479.25 30 32 0.59 293 12 0.012 474.28 475.75 0.79 0.75 O.ot 476.52 0.0, 476.75 0.00 0.01 476.76 476.75 O.OI O.Ql 0.00 476.77 491.04 32 33 0.59 181 12 0.012 475.75 476.66 0.79 0.75 o.ot 476.77 0.04 477.66 0.00 0.01 477.67 477.66 0.01 0.00 0.00 477.67 486.52 33 34 0.59 67 12 0.012 476.66 477.00 0.79 0.75 0.01 477.67 0.02 478.00 0.00 0.01 478.0i 478.00 0.01 0.01 0.00 478.02 480.60 34 35 OS9 20 12 0.012 4TI.OO 477.20 0.79 0.75 0.01 478.02 0.00 478.20 0.00 0.01 478.21 478.20 000 noo uoo 47&.21 480.60 33 36 0.59 150 12 0-012 476.66 477.71 0.79 0.75 0.01 477.67 0.03 478.71 0.00 0.01 478.72 478.71 O.ot 0.00 000 478.71 483.81 36 36A 0.59 150 12 0.012 477.71 478.46 0.79 0.75 0.01 478.71 0.03 479.46 0.00 O.Ql 479.47 479.46 0.01 0.00 0.00 479.46 482.64 36A 37 0.59 89 12 0.012 478.46 478.91 0.79 0.75 O.QJ 479.46 0.02 479.91 0.00 O.OI 479.92 479.91 0.00 0.00 0.00 479.92 482.01 40A 40 1.28 16 12 0.012 470.02 475.19 0.79 l.63 0.04 477.62 0.02 477.64 0.02 0.04 477.70 476.19 0.04 0.01 C.02 477.69 482.10 40 408 1.28 16 12 0.012 477.94 478.26 0.79 1.63 0.04 477.69 0.02 479.26 0.02 0.04 479.32 479.26 0.00 0.00 0.00 479.32 481.74 40 41 1.28 IOI 12 0.012 475.19 475.70 0.79 1.63 0.04 477.69 0.11 477.80 O.Q2 0.04 477.86 476.70 0.04 0.05 002 477.90 482.87 41 42 1.28 66 12 0.012 475.70 476.16 0.79 1.63 0.04 477.90 0.07 477.97 0.02 0.04 478.03 477.16 0.04 o.os 0.00 478.04 478.99 42 43 1.28 34 12 0.012 476.16 476.50 0.79 1.63 0.04 478.04 0.04 478.08 0.02 0.04 478.14 477.50 0.00 0.00 000 478.14 478.99 41 44 1.28 189 12 0.012 475.70 484.02 0.79 1.63 0.04 477.90 0.21 485.02 0.02 0.04 485.08 485.02 0.04 0.00 0.02 485.06 490.12 44 45 1.28 30 12 0.012 4S4.02 487.02 0.79 1.63 0.04 485.06 0.03 488.02 0.02 0.04 488.08 488.02 0.00 0.00 0.00 488.08 490.12 44 46 1.28 78 12 0.012 4S4.02 484.41 0.79 1.63 0.04 485.06 0.08 485.41 0.02 0.04 485.47 485.41 0.04 0.00 0.02 485.45 487.83 46 47 l.28 22 12 0.012 484.41 484.63 0.79 1.63 0.04 485.45 0.02 485.63 0.02 0.04 485.69 485.63 0.00 0.00 0.00 485.69 487.83 46 48 1.28 35 12 0.012 484.41 484.76 0.79 1.63 0.04 485.45 0.04 485.76 0.02 0.04 485.82 485.76 0.00 0.00 0.00 485.82 487.84 44 49 1.28 172 12 0.012 484.02 487.98 0.79 l.63 0.04 485.06 0.19 488.98 0.02 0.04 489.04 488.98 0.04 o.os 000 489.06 491.81 '" '" ' " '" " 0.012 487.98 488.58 0.79 l.63 0.04 489.06 0.03 489.58 0.02 0.04 489.64 489.58 0.00 0.QO e.oo 489.64 491.78 BACKWATER CALCIJLATIONS OBJ'\AME: EVENDELL PREPARED BY: G.Brooks OB 1''UMBER: ..... DF.5IGN STORM: 100 YEAR EllriTR.0.CE E!'l.'TRANCE EXIT OUTLET INLET APPROACH BEl\'D JUNCilON PIPE PIPE MANNING'S OUI'LET INLET PIPE FLOW VELOOTY TAILWATER FRICTION HGL HEAD HEAD CONTROL CONTROL VELOOTY HEAD HEAD HEADWATER FROM TO FLOW LE.~GTH DIA. " ELEVATION ELEVATION AREA VELOCITY HEAD ELEVATION LOSS ELEVATION LOSS LOSS ELEVATION ELEVATION HEAD LOSS LOSS ELEVATION CB CB (CFS) (F"~ (IN) VALUE (FEET) (FEET) ,•nm (Ff/SEC) (FEET) (FEET) (FEETI =En (li'Ji'ET) (FEET) (FEET) (FEET) (FEET) (FEET (FEET) (FEET\ RIMEL 5B 4 052 206 12 0.012 454.07 455.10 0.79 0.66 0.01 459.79 0.04 459.83 0.00 0.01 459.84 4.56.10 O.Ql 0.01 0.00 459.84 462.00 4 3 052 80 12 0.012 455.10 456.30 0.79 0.66 0.01 459.84 0.01 459.85 0.00 0.01 459.86 457.30 o.oo 0.00 0.00 459.86 459.30 5A ' '·" " 18 0.012 448.50 453.01 1.77 4.83 0.36 458.11 0.32 458.43 0.18 0.36 458.98 454.89 0.23 0.33 0.17 459.25 463.41 5 '" 4.73 90 15 0.012 453.34 456.00 1.23 3.85 0.23 459.25 0.41 459.66 0.12 0.23 460.00 457.25 0.23 0.00 0.02 459.79 465.56 5 6 3.81 so 12 0.012 453.51 459.42 0.79 4.85 0.37 459.2.5 0.48 460.42 0.18 0.37 460.97 460.97 0.37 0.48 0.0) 461.09 463.15 6 7 3.81 24 12 0.012 459.42 459.66 0.79 4.85 037 461.09 0.23 461.32 0.18 0.37 461.87 461.26 0.37 0.48 0.00 461.98 463.15 7 8 3.81 44 12 0.012 459.66 459.88 0.79 4.85 0.37 461.98 0.42 462.41 0.18 0.37 462.96 461.48 0.37 0.19 0.00 462.78 46.U6 ' 9 3.81 142 12 0.012 459.88 462.15 0.79 4.85 0.37 462.78 l.37 464.15 0.18 0.37 464.70 463.75 0.37 O.Q2 0.20 464.55 466.16 9 IO 3.81 26 12 0.012 462.15 462.83 0.79 4.85 0.37 464.55 0.25 464.81 0.18 0.37 465.35 464.42 0.00 0.00 0.00 465.35 466.33 9 }I 3.81 102 12 0.012 462.15 464.SO 079 4.85 037 464.55 0.98 465.54 0.18 0.37 466.09 466.JO 037 034 020 46627 468.23 11 12 3.81 16 12 0.012 464.50 464.66 0.79 4.85 0.37 466.27 0.15 466.42 0.18 0.37 466.97 466.26 0.00 0.00 0.00 466.97 468.73 11 )3 3.81 " 12 0.012 464.50 465.56 0.79 4.85 0.37 466.27 0.51 466.78 0.18 0.37 467.33 467.16 0.37 0.42 0.00 467.39 469.30 13 14 3.81 24 12 0.012 465.56 465.80 0.79 4.85 037 467.39 0.23 467.62 018 0.37 468.17 467.40 0.37 0.48 0.00 468.28 469.30 14 IS 3.81 183 12 0.012 465.80 471.29 0.79 4.85 0.37 468.28 1.77 472.29 0.18 0.37 472.84 472.88 0.37 0.28 0.00 472.79 474.76 15 16 3.81 26 12 0.012 471.29 471.55 0.79 4.85 0.37 472.79 0.25 473.04 0.18 0.37 473.59 473.15 0.00 0.00 0.00 473.59 475.08 SB 17 4.73 32 15 0.012 456.00 462.98 1.23 3.85 0.23 459.25 0.14 464.23 0.12 0.23 464.58 464.23 0.23 0.00 0.13 464.48 466.76 17 18 4.73 24 12 0.012 463.23 463.47 0.79 6.02 O.S6 464.48 0.36 464.83 0.28 0.56 465.68 465.58 0.56 0.00 0.00 465.12 466.76 18 19 4.73 }} 12 0.012 463.47 463.80 0.79 6.02 0.56 465.12 0.16 465.28 0.28 0.56 466.13 465.90 0.00 0.00 0.00 466.13 467.39 17 20 4.73 73 15 0.012 462.98 465.46 ).23 3.85 0.23 464.48 0.33 466.71 0.12 023 467J)6 466.71 0.56 0.04 0.13 466.66 469.42 20 21 4.73 24 12 0.012 465.71 465.9S 0.79 6.02 0.56 466.66 0.36 467.0l 0.28 0.56 467.86 468.06 0.00 0.00 0.00 468.06 469.42 20 22 4.73 8) 12 0.012 465.71 468.71 0.79 6.02 0.56 466.66 ).20 469.71 0.28 0.S6 470.56 470.81 0.56 0.13 0.00 470.37 472.24 22 23 4.73 90 12 0.012 468.71 471.05 0.79 6.02 0.56 470.37 l.34 472.05 0.28 0.56 472.90 473.15 O.S6 0.10 0.31 473.00 474.57 23 24 4.73 24 ).2 0.012 471.05 47l..53 0.79 6.02 0.56 473.00 0.36 473.36 0.28 0.56 474.20 473.63 0.00 0.00 0.00 474.20 474.55 23 25 4.73 2) 12 0.012 471.05 471.68 0.79 6.02 0.56 473.00 0.31 473.31 0.28 0.56 474.16 473.78 O.S6 0.03 0.31 473.94 475.22 25 26 4.73 24 12 0.012 471.68 471.92 0.79 6.02 056 473.94 0.36 474.30 0.28 0.56 475.14 474.03 0.00 0.00 0.00 475.14 475.43 25 27 4.73 99 12 0.012 471.68 474.16 0.79 6.02 0.56 473.94 1.47 475.41 0.28 0.56 476.26 476.26 0.00 0.00 0.00 476.26 477.66 23 28 4.73 1)2 12 0.012 471.05 472.73 0.79 6.02 056 473.00 1.67 474.67 021! 0.56 475.51 474.84 0.56 O.ot 0.00 474.95 476.55 28 29 4.73 142 12 0.012 472.73 474.14 0.79 6.02 0.56 474.95 2.11 477.06 0.28 0.56 477.91 476.25 0.56 0.11 0.00 477.46 479.07 29 30 4.73 28 12 0.012 474.14 474.28 0.79 6.02 0.56 477.46 0.42 477.88 0.28 O.S6 478.72 476.39 0.02 0.32 0.68 479.70 479.22 30 31 4.73 29 12 0.012 475.66 476.24 0.79 6.02 0.56 479.70 0.43 480.13 028 0.56 480.98 478.34 0.00 0.00 0.00 480.98 479.25 30 32 0.81 293 12 0.012 474.28 475.75 0.79 1.03 0.02 479.70 0.13 479.83 O.Ql 0.02 479.86 476.75 0.02 0.02 0.00 479.86 491.04 32 33 0.81 181 12 0.012 415.15 476.66 0.79 1.03 0.02 479.86 0.08 479.94 O.Ql 0.02 479.97 477.M 0.02 0.00 0.01 479.96 486.52 33 34 0.81 67 12 0.012 476.66 477.00 0.79 1.03 0.02 479.96 0.03 479.99 0.01 0.02 480.01 478.00 0.02 0.02 0.00 480.02 480.60 34 " 0.81 20 12 0.012 477.00 477.20 0.79 1.03 0.02 480.02 o.ot 480.03 0.01 0.02 480.05 478.20 0.00 0.00 0.00 480.05 480.60 33 36 0.81 150 12 0.012 476.66 477.71 0.79 I.03 0.02 479.96 OJJ7 480.02 O.QJ 0.02 480.05 478.71 0.02 0.00 0.00 480.03 483.81 36 36A 081 ISO 12 0.012 477.71 478.46 079 1.03 002 480.03 0.07 480.10 0.01 0.02 480.12 479.46 002 0.00 000 480.11 482.64 36A 37 0.81 89 12 0.012 478.46 478.91 0.79 1.03 0.02 480.JI 0.04 480.14 0.01 0.02 480.17 479.91 0.00 0.00 0.00 480.17 482.01 40A 40 l.79 16 12 0.012 470.02 475.19 0.79 2.28 0.08 477.62 O.o3 477.65 0.04 0.08 477.78 476.19 0.08 0.01 0.04 477.75 482.10 40 40B 1.79 16 12 0.012 477.94 478.26 079 2.28 0.08 477.75 003 479.26 0.04 0.08 479.38 479.26 0.00 0.00 0.00 479.38 481.74 40 41 1.79 IOI 12 0.012 475.19 475.70 0.79 2.28 0.08 4TI.75 0.22 477.97 0.04 0.08 478.09 476.70 0.08 0.11 0.04 478.16 482.87 4) 42 l.79 66 12 0.012 475.70 476.16 0.79 2.28 0.08 478.16 0.14 478.30 0.04 0.08 478.42 477.16 0.08 0.11 0.00 478.45 478.99 42 43 1.79 34 12 0.012 476.16 476.50 079 2.211 0.08 478.45 007 478.52 0.04 0.08 47R64 477.50 0.00 000 0.00 478.64 478.99 41 44 1.79 189 12 0.012 475.70 484.02 0.79 2.28 0.08 478.16 0.40 485.02 0.04 0.08 485.14 485.02 0.08 0.00 0.04 485.10 490.12 44 " 1.79 30 12 0.012 484.02 487.02 0.79 2.28 0.08 48.'i.lO 0.06 488.02 0.04 0.08 488.14 488.02 0.00 0.00 0.00 488.14 490.12 44 46 1.79 78 12 0.012 484.02 484.41 0.79 2.28 0.08 485.10 0.17 485.41 0.04 0.08 485.53 485.41 0.08 0.00 0.04 485.50 487.83 46 47 1.79 22 12 0.012 484.41 484.63 0.79 2.28 0.08 485.50 0.05 485.63 0.04 0.08 485.75 485.63 0.00 0.00 0.00 485.75 487.83 46 48 1.79 " 12 0.012 484.41 484.76 0.79 2.28 0.08 485.50 0.07 485.76 0.04 0.08 485.88 485.76 0.00 0.00 0.00 485.88 487.84 44 49 l.79 172 12 0.012 484.02 487.98 0.79 2.28 0.08 485.10 0.37 488.98 0.04 0.08 489.10 488.98 0.08 0.11 000 489.13 491.81 ,o <O '" '° 12 0.012 487.98 488.511 0.79 :p~ 0.08 ·--489.13 0.06 489.58 0.04 0.08 489.70 489.58 0.00 0.00 000 489.70 491.78 Flow Frequency Analysis Time series File:dwest15.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.619 6 8/27/01 18:00 0.432 8 9/17/02 17:45 1. 28 2 12/08/02 17:15 0. 499 7 B/23/04 14 :30 0.689 5 11/17/04 5:00 0. 726 4 10/27/05 10:45 0.857 3 10/25/06 22:45 1. 79 1 1/09/08 6:30 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 1.79 1 100.00 0.990 1. 28 2 25.00 0. 960 0.857 3 10.00 0.900 0. 726 4 5.00 0.800 0.689 5 3.00 0.667 0.619 6 2.00 0.500 0.499 7 1.30 0.231 0.432 8 1.10 0.091 1. 62 50.00 0.980 Flow Frequency Analysis Time Series File:deast15.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 3. 18 6 8/27/01 18,00 2.22 8 9/17/02 17, 45 6.52 2 12/08/02 17,15 2.57 7 8/23/04 14, 30 3.51 5 10/28/04 16,00 3.71 4 10/27/05 10 ,45 4.40 3 10/25/06 22,45 9.03 1 1/09/08 6,30 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 9.03 1 100.00 0.990 6.52 2 25.00 0. 960 4.40 3 10.00 0.900 3.71 4 5.00 0.800 3.51 5 3.00 0.667 3.18 6 2.00 0.500 2.57 7 1. 30 0.231 2.22 8 1.10 0.091 8.19 50.00 0.980 Flow Frequency Analysis Time Series File,upeastl5.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.024 2 2/09/01 17,15 0.007 7 1/06/02 2,30 0.017 4 3/06/03 18,30 0.001 8 3/08/04 22,45 0. 011 6 1/05/05 7,30 0.018 3 1/18/06 20,15 0.015 5 ll/24/06 4, 15 0.039 l 1/09/08 9,30 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.039 1 100.00 0.990 0.024 2 25.00 0.960 0.018 3 10.00 0.900 0.017 4 5.00 0.800 0.015 5 3.00 0.667 0. Oll 6 2.00 0.500 0.007 7 l. 30 0.231 0.001 8 l.10 0.091 0.034 50.00 0.980 Flow Frequency Analysis Time Series File:postelS.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 3.18 6 8/27/01 18,00 2.22 8 9/17/02 17,45 6.54 2 12/08/02 17,15 2.57 7 8/23/04 14 ,30 3.51 5 10/28/04 16,00 3.71 4 10/27/05 10,45 4.40 3 10/25/06 22,45 9.06 1 1/09/08 6,30 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 9.06 1 100.00 0.990 6.54 2 25.00 0. 960 4.40 3 10.00 0.900 3.71 4 5.00 0.800 3.51 5 3.00 0.667 3.18 6 2.00 0.500 2.57 7 1. 30 0.231 2.22 8 1.10 0.091 8.22 50.00 0.980 Flow Frequency Analysis Time Series Filel:S:9.lif . .,tsf--,' Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return (CFS) (CFS) (ft) Period 0.120 2 2/09/01 20:00 0.222 G..,32 _ 1 100.00 0.032 7 12/28/01 18:00 a .120 6.54 2 25.00 0.086 5 3/06/03 22:00 0.107 5.87 3 10.00 0.030 8 B/26/04 7:00 0.087 5.07 4 5.00 0.057 6 1/05/05 15:00 0.086 5.01 5 3.00 0.087 4 1/18/06 23:00 0.057 3.91 6 2.00 0.107 3 11/24/06 7:00 0.032 3.29 7 1.30 0.222 1 1/09/08 11:00 0.030 2.77 8 1.10 Computed Peaks 0.188 7.41 50.00 c9-6~r l,uC'0Q_\.Q~.:: .e'..\-11of)·t 0.:::>4-_4,7.(p~; \ Ql) L~r \,'0 ~ (_\.L\J ;;c 41 I . 06 -t /. 4~ 4, e) ":() Prob 0.990 0.960 0.900 0.800 0.667 0.500 0.231 0.091 0.980 Flow Frequency Analysis _ Time series Fil~:eout.tsf Project Location':sea-Tac ---Annual Flow Rate (CFS) 0.673 0.164 0.505 0.148 0.177 0.408 0. 572 Peak Flow Rates--- Rank Time of Peak 2 7 4 8 6 5 3 1 2/09/01 20:00 12/29/01 10:00 3/06/03 22: 00 8/26/04 7:00 1/08/05 2:00 1/18/06 23:00 11/24/06 8:00 1/09/08 10:00 2.20 computed Peaks EOUT.PKS -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft)/;___; Period 2. 20 7 .1:v 1 100. oo 0.673 ,6~69 -2 C25.00 0.572 6.11 3 10:--00 0.505 5.81 4 5.00 0.408 5.47 5 3:00 0.177 4.55 6 2.00 0.164 3.87 7 1.30 0.148 3.19 8 1.10 1.69 7.06 50.00 0.990 0.960 0.900 0.800 0.667 0. 500 0.231 0.091 0.980 25-year water surface= ~51.0 + 6.69 = 457.69 100-year water surface= 451.0 + 7.11 = 458.11 Page 1 OFF-SITE DRAINAGE SYSTEM Some culverts along SE 1361h Street and 1601h Avenue SE were relocated, added, and/or replaced. Also, due to proposed shoulder installation along 1601 h Avenue SE, the existing ditch along the west side of the road was relocated behind the proposed shoulder. A tightlined bypass storm drainage was installed just upstream of the discharge location for the proposed wetpond and downstream past the proposed Nichols development. The off- site drainage system was sized to convey the 25-year and JOO-year flows calculated in the Level 3 Downstream Drainage Analysis by Haozous Engineering, dated August 26, 2002. See Section 6 of this report for a copy of the report. For simplicity and since some of the culverts that will be reconstructed for this project will be temporary, the Liberty Grove development frontage improvements will include installation of a new storm drainage system, those culverts were sized based on an assumed free flow condition through the culvert for the I 00-year, 24-hour peak flow. All other permanent culverts were initially analyzed to verify headwater elevations are no more than 2 times the diameter for 18" diameter pipe or less and no more than 1.5 times the diameter for pipes exceeding 18" for the 25-year peak flow per Section 4.3.1 and Section 1.2.4.1 of the 1998 KCSWDM. The headwater elevations were then checked to verify the headwater elevations are contained within the proposed ditch culvert system during the 100-year peak flow. The new temporary culvert that crosses under 1581h Avenue SE on the north side of 1361 h Avenue SE was sized based on the JOO-year flow rate from tributary area el delineated in the Level 3 analysis. The I 00-year flow rate is 7. IO cfs. The minimum culvert size at a slope of 1.1 % is a 15" to convey the I 00-year flow rate at freeflow conditions. Q(full) = 1.49/n* A *R213 *S 1/2, from nomograph fig. 4.2.1.F, velocity in pipe will be approx. 6.0 fps. The new temporary culvert that crosses SE 1361h Street along the west side of 1601h Avenue SE was sized based on the 100-year flow rate from tributary areas el and e2 delineated in the Level 3 analysis. The I 00-year flow rate is 20.33 cfs. The minimum culvert size at a slope of 0. 7% is a 24" to convey the I 00-year flow rate at freeflow conditions. Q(full) = 1.49/n* A *R213 *S 112 = (l .49/0.012)(1t/4*2 2 ) ( 112)213(0.001)11 2 = 20.56 cfs > 20.33 cfs. The new ditch that runs along the west side of 1601h Avenue SE was sized based on the JOO-year flow rate from tributary areas el, e2, and "exeast" delineated in the Level 3 analysis. The 100-year flow rate is 22.46 cfs. The ditch will not need to be rock-lined since the flows within a vegetated ditch would be less then 5 fps. See attached excel spreadsheet labeled 1601h Rock-Lined Ditch Analysis on the following pages. AV-ditch at a minimum slope of2.5% can carry the required.flow at 1.32' depth. The V-ditch will be designed with a depth of 1.5 '. The new pennanent culverts that nm along the west side of 1601h Avenue SE at the southern end of the site were sized based on the flow rates from tributary areas el, e2, and "ex east" delineated in the Level 3 analysis. The 25-yearand l 00-year flow rates are 18.32 cfs and 22.46 cfs consecutively. The minimum culvert size at a slope of 0.9% is a 24" to convey the 100-year flow rate at freeflow conditions. Q(full) = 1.49/n* A *R213 *S 112 = ( 1.49/0.0 l 2)(1t/4*2 2) (112f3 (0.009)112 = 23.31 cfs > 22.46 cfs. The culverts were checked for inlet control to verify headwater compliance with the 1998 KCSWDM. The. outlet is not submerged and therefore, does not affect the headwater elevation at the intake. The equations used for the inlet control analysis are listed on page 4-37 of the 1998 KCSWDM. 25-Year Peak Flow: Q!AD05 = !8.32/[(n/4)(2)2(2)05 ] = 4.12 > 3.5 ~ SUBMERGED CONDITION HW/D = c(Q/AD05 )2 + Y -0.5S Per Table 4.3.1.A: c = 0.0398 & Y = 0.67 ( circular cone with sq. edge with headwall) HW ID = 0.0398( 4.12)2 + 0.67 -0.5(0.009) = 1.34 < 1.5 ~ OK I 00-Year Peak Flow: Q/AD05 = 22.46/[(n/4)(2)2(2)05] = 5.06 > 3.5 ~ SUBMERGED CONDITION HW/D = c(Q/AD05)2 + Y -0.5S Per Table 4.3.1.A: c = 0.0398 & Y = 0.67 (circular cone with sq. edge with headwall) HW/D = 0.0398(5.06)2 + 0.67 -0.5(0.009) = 1.68 HW = 1.38*2 = 3.37' The tightlined system that runs along the west side of 1601h Avenue SE downstream of the most southerly junction catch basin that captures flows from the future Nichols development was sized based on the l 00-year flow rate from tributary areas el, e2, e3, and "exeast" delineated in the Level 3 analysis. The I 00-year flow rate is 23.38 cfs. The minimum culvert size at a slope of 1.0% is a 24". Q(full) = I .49/n* A*R213 *S 112 = (1.49/0.012)(1t/4*i2) (112/13 (0.01)112 = 24.57 cfs > 23.38 cfs. Since d_rainage is already in a tightlined system, it is not necessary to calculate the headwater elevation at the inlet. Also, the outlet is not submerged and therefore, does not affect the headwater elevation at the junction catch basin. I •••••••••••••• .. •••••• 16offi I{QGK-L-INE:t>• Pft¢H ANAJD¥$ts•••• <I DITCH DATA: BOTTOM WIDTH (FT)= 0.00 JOB NAME: EVENDELL LEFT SIDE SLOPE (L:1) 3.00 JOB#: 04009 RIGHT SIDE SLOPE (R:l 3.00 OPERATOR: J.A. Morin BOTTOM SLOPE (FT/FT 0.0500 DATE: 9/5/2004 MANNING'S n = 0.050 FLOW FLOW WETTED HYDRAULIC DITCH FLOW DEPTH AREA PERIMETER RADIUS CAPACITY VELOCITY (FEET) (SQ FT) (FEET) (FEET) (CFS) (FPS) 0.00 0.0000 0.0000 0.0000 0.000 0.000 0.05 0.0075 0.3162 0.0237 0.004 0.549 0.10 0.0300 0.6325 0.0474 0.026 0.871 0.15 0.0675 0.9487 0.0712 0.077 1.14] 0.20 0.1200 1.2649 0.0949 0.166 1.382 0.25 0.1875 1.5811 0.1186 0.301 1.604 0.30 0.2700 1.8974 0.1423 0.489 1.811 0.35 0.3675 2.2136 0.1660 0.738 2.007 0.40 0.4800 2.5298 0.1897 1.053 2.194 0.45 0.6075 2.8460 0.2135 1.442 2.374 0.50 0.7500 3.1623 0.2372 1.910 2.546 0.55 0.9075 3.4785 0.2609 2.462 2.713 0.60 1.0800 3.7947 0.2846 3.105 2.875 0.65 1.2675 4.1110 0.3083 3.844 3.033 0.70 1.4700 4.4272 0.3320 4.684 3.187 0.75 1.6875 4.7434 0.3558 5.630 3.337 0.80 1.9200 5.0596 0.3795 6.688 3.483 0.85 2.1675 5.3759 0.4032 7.861 3.627 0.90 2.4300 5.6921 0.4269 9.156 3.768 0.95 2.7075 6.0083 0.4506 10.576 3.906 1.00 3.0000 6.3246 0.4743 12.126 4.042 I. I 0 3.6300 6.9570 0.5218 15.635 4.307 1.20 4.3200 7.5895 0.5692 19.718 4.564 1.30 5.0700 8.2219 0.6166 24.410 4.815 1.32 5.2272 8.3484 0.6261 25.424 4.864 1.40 5.8800 8.8544 0.6641 29.743 5.058 1.50 6.7500 9.4868 0.7115 35. 751 5.296 1.60 7.6800 10.1193 0.7589 42.465 5.529 1.70 8.6700 10.7517 0.8064 49.917 5.757 1.80 9.7200 11.3842 0.8538 58.136 5.981 1.90 10.8300 12.0167 0.9012 67.152 6.201 2.00 12.0000 12.6491 0.9487 76.995 6.416 ,.. 6. SPECIAL REPORTS AND STUDIES: Included in this section are the postmaster approval; the Preliminary T.I.R. by Haozous Engineering., dated June 15, 2001; the Level 3 Downstream Drainage Analysis by Haozous Engineering., dated August 26, 2002; the Preliminary Geotechnical Engineering Report by US Land Development Associates, dated November 16, 2001; the Wetland Report by Habitat Technologies, dated October 28, 2002 (addendum) and May 15, 2001; the vault structural plans as prepared by Miles Consulting, dated May 2004, a letter from Bruce and Joyce Osgoodby (property owners on north side of SE 1361h Street), dated July 14'\ 2004, allowing permission to enter the property for installation of rockery and regrading of existing driveway; a letter from Bruce and Joyce Osgoodby, dated September 27'\ 2004, allowing permission to enter the property for reconstruction of keystone wall; transfer of density credit documentation; copy of Boundary Line Adjustment; copy of · recorded drainage easement. '" "· ·a (5) (\J 0 z: u :::: ~· C. 11'. ('. '··· :::. "· ,., "' t,i L~I ,,, "' t,'d t,02'0N I _, ,_ ., ~ • I R • II .. I -=-..P ... • • -~r--------------- JNI tJ~I53Q 32:10) Wd<;E:J t,002'£ '2:!dl:! ~ ·1 i • 3 ~!9 -· \ -.. -.:, ··--·- ~ . II ; ~\ • ~~ J:; . I i ·/ . II . r ----- • I > l• lra .. . . 13 -,.., ~ • . R . ;;, A ~-,1,}; .. .. J -'i ~ . t: = -~ .... ./ ;! . -:::_ -~ ' .,.1 Evendell Plat ,.~, 1· ' ...,... i . '.././ ,, .... ~ .·.:--. / Preliminary Technical Information Report Submitted to: King County DDES 900 Oakesdale Avenue S.W. Renton, WA 98055 . Prepared by: Haozous Engineering, P.S. 14816 SE 116th Street Renton, WA 98059 Tel. ( 425) 235-2707 Fax ( 425) 254-0579 June 15, 2001 /%f #§&gW 9§h di ii: RI,% '1th r#Ef§ ;. ¥· 0 TABLE OF CONTENTS ·''· 1. Project Overview ...................................................... : ........................................................ 1-1 2. Conditions and Requirements Summary ........................................................................... 2-1 3. Offsite Analysis ................................................................................................................. 3-1 4. Flow Control and Water Quality Facility Analysis and Design ........................................ 4-1 5. Conveyance System Analysis and Design ......................................................................... 5-1 6. Special Reports and Studies .............................................................................................. 6-1 7. Other Permits .................................................................................................................... 7-1 8. ESC Analysis and Design ................................................................................................. 8-1 9. Bond Quantities, Facility Summaries, and Declaration of Covenant ................................ 9-1 I 0. Operations and Maintenance Manual.. .......................................................................... 10-1 11. References ..................................................................................................................... 11-1 LIST OF TABLES Table I. Description of Downstream Conveyance System ................................................... 3-5 Table 2. Existing and Developed Site Basin Conditions ...................................................... 4-2 Table 3. Summary of Performance Standards ....................................................................... 4-3 Table 4. Wet Pond Sizing Calculations .............................................................................. .4-11 Table 5. Summary of Special Reports and Studies ............................................................... 6-1 Table 6. Summary of Other Permits Required ....................... : ........................................ : ..... 7-1 Table 7. Summary of Maintenance Requirements for Storm water Facilities ..................... 10-1 b D I D b LIST OF FIGURES Figure 1. TIR Worksheet. ...................................................................................................... 1-2 Figure 2. Vicinity Map .......................................................................................................... 1-5 Figure 3. Drainage Basins ..................................................................................................... 1-6 Figure 4. Soils Map ............................................................................................................... 1-7 Figure 5. Downstream Conveyance System .......................................................................... 3-4 Figure 6. Stormwater System Design .................................................................................... 4-6 Figure 7 A. Flow Duration Curves for RID -East Basin ...................................................... .4-7 Figure 7B. Flow Duration Curves for RID -West Basin .......... : ........................................... 4-9 Figure 8. Erosion and Sedimentation Control Plan ............................................................... 8-2 Figure 9. Site Improvement Bond Quantity Worksheet.. ...................................................... 9-2 Figure 10. Flow Control and Water Quality Facility Summary ............................................ 9-3 APPENDICES Appendix A. Downstream System Appendix B. Stormwater RID System Design Appendix C. Conveyance Calculations Appendix D. Hydrologic Model Documentation ii 1. Project Overview Project Description A summary of the Evendell Plat project is provided in the TIR Worksheet (Figure 1 ). This preliminary technical information report (TIR) addresses the design of stormwater facilities and the offsite drainage analysis for the Evendell Plat project. The Evendell Plat project is a proposed residential development located within the Renton Highlands area of unincorporated King County (Figure 2). The proposal for development includes building 75 single-family dwellings on approximately 12 acres. Road improvements along SE 136th Street are also proposed. The proposed site plan is provided in Figure 6 of Section 4. 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 consists of two basins. The topography of the east basin generally slopes from the northwest to the southeast (Figure 3). The topography of the west basin generally slopes from the east to the west. The elevation of the site ranges from about 494 feet (NA VD 88) in the north portion of the site to 456 feet in the southeast corner. The project is located east of 156th Avenue SE and is bordered by SE 136th Street on the north and by 160'h A venue SE on the east. Cover types on the site include a single-family residence, pasture, and forest (Photo I in Appendix A. I). A Class 2 wetland has been identified in the northeast portion of the site. Based on King County Soil Survey (U.S. Department of Agriculture, 1973) the site consists of Alderwood soils (Figure 4). Drainage from an approximately 0. 94-acre tributary sub basin adjacent to the west boundary of the easterly basin sheet flows onto the site (Figure 3). The easterly basin drains to a conveyance system along l 60'h A venue SE. The westerly basin drains to a conveyance system along 156th 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). Stormwater Design Under developed conditions, stormwater from the site and offsite road improvements will be collected and treated onsite to basic water quality standards. A combined wetpond/detention pond will be used to manage runoff in the easterly basin. A small wetvault will provide water quality treatment to a portion of SE 136th Street that bypasses the stormwater facility in the east basin. A vault followed by a biofiltration swale will be used to manage runoff in the westerly basin. Level 2 RID standards are required by the King County Flow Application Maps and recommended by Lower Cedar River Basin and Nonpoint Action Plan. Natural discharge locations from the site will be maintained at the outlet of the proposed stormwater facilities. 1-1 EvendeO Plat Preliminary TIR-June 2001 Figure 1. TIR Worksheet TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner: U.S. Land Development Associates, Inc. Address: Clo: Mike Romano Centurion Development Services · 22617 8th Dr. SE Bothell, WA 98021 Phone: (425) 486-2563 Project Engineer: Ed McCarthy, P.E. Company: Haozous Engineering, P.S. Address/Phone: 14816 SE 116th Street Renton, WA 98059 (425) 235-2707 Part 3 TYPE OF PERMIT APPLICATION ~ Residential ~ Grading Part 2 PROJECT LOCATION AND DESCRIPTION Project Name: Evendell Plat Location: West of 16oth Avenue SE and bordered by SE 136th Street on the north. Township: 23N Range: 5E Section: 14 Description: The proposal for development includes building 75 single-family dwellings on approximately 12 acres. Part 4 OTHER REVIEWS AND PERMITS D DFWHPA @ Wetlands ® National Pollutant Discharge Elimination System (NPDES) Stormwater Permit @ Forest Practices Class IV General Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: King County Drainaae Basin: Lower Cedar River Watershed; Ortina Hills subbasin Part 6 SITE CHARACTERISTICS D River: NIA D Stream: NIA D Critical Stream Reach: NIA D Depressions/Swales: N/A D Lake: NIA D Steep Slopes: N/A D Floodplain: NIA ® Wetlands: Onsite Class 2 Wetland D Seeps/Springs: NIA D High Groundwater Table: N/A D Groundwater Recharae: N/A 1-2 I Part 7 SOILS Soil Type Alderwood Slopes Moderate Part 8 DEVELOPMENT LIMITATIONS REFERENCE Ch 6 -Water Quality Requirements Ch 5 -Flow Control Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION ig) Sedimentation Facilities ig) Stabilized Construction Entrance ig) Perimeter Runoff Control ig) Cover Practices ig) Construction Sequence Part 10 SURFACE WATER SYSTEM Erosion Potential Erosive Velocities LIMITATION/SITE CONSTRAINT Onsite treatment -basic standards Level 2 R/D standards MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION ig) Stabilize Exposed Surface ~ Remove and Restore Temporary ESC Facilities ~ Clean and Remove AH Silt and Debris ~ Ensure Operation of Permanent Facilities Basin Water Qualirv Treatment Detention East Wetoond/Wetvault Level 2 Pond West Biofiltration swale Level 2 Vault Facility Related Site Design Considerations: Reference Facility Design Consideration 1-3 Part 11 STRUCTURAL ANALYSIS ~ Rockery> 4' High 0 Berms > 6': NIA Part 12 EASEMENTSffRACTS 0 Drainage Easement: NIA 0 Access Easement: NIA 0 Native Growth Protection Easement ~ Sensitive areas ~ Stormwater tracts Part 13 SIGNATURE OF PROFESSIONAL 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. 1-4 : :::, C • • .• D r. ! ---o-,. • SE••'' ··,, ,o \: \. . . ... 139 \' ' .-1 : ,! . ·tia,b~f, 118TH '! 'C p.,6;,~ \ / \,~o •\' \ -,. •o··. ~ ·,o SOURCE: USGS 7.5 x 15 Minute Series -Renton, Washington SCALE: 1 :25 000 TITT.E PAGE \~ .. ·.' Figure 2. Vicinity Map DATE 1-5 01/03/01 1,.i.\· v·.· ~---- 5C.'U: IN Fm 200 ._,,. I I I I I DATE NO. UI ... ~~,E---'iCii' ii" :::J u ~\: --\ l\t\ -' >( ~-·-;_ ()ii::_· ~e Dt -Jh. ( -~-~ "" , -;:;7. r \. • .J '<. 'i_,,.,,Jv l ,. r,.-.,., t C ! ,..,,.,N""'I, I.(' l~ L . I; I / Wh I \ \ "' jll\ [ \ / I + I \ ==!.IJL ... [ f ~ D c:::J ' 1il~~ \ll " ·\~~I uJ' 0~ '°">- ' " I· """~-01 '\ .. ' ~IJ. ·1.\.,. \.,. u,_ .\~· I ' .-,v \:: ::::::'1"'1 ;i;:_c [ [ ·1 I [ ~ I_,''·-''"'...,,,.,,,"-, l ' l.l • RE11SION BY ' [ r , ,. I r C LP -D 0 I, ")\ EVENDEL~ ast" fa3 AC) _.,so 0 0 (" <'"" <"> '""' ("" ,..., ""' '""t C [ <v....., \l,l'l .J \'' <.w~J ~~~~ Haozous Engineering CIVIL ENGINEERING 14816 SE 116TH ST, RENTON, \,/A 96059 42S-235•2707 ------------ O[Sl(J,l[D B'rl I DAT(: EJM 1/08/01 PftA'flM 11', --------·· --~v~s/01 EJM EVENDELL PLAT Figure 3. Drainage Basins PROJECT NO. SHEET 1-6 Of SCALE: 1 :24 000 1" = 2,000' TTTlE PAGE Figure 4. Soils Map DATE 1-7 01/03/01 2. Conditions and Reqiiireni~nts S'uininary ·. · · A summary of conditions and requirements for the project are presented in this section. The following is a summary of core and special requirements from the 1998 King County Surface Water Design Manual: Core Requirement 1: Discharge at the Natural Location The natural discharge locations from the site will be maintained at the outlets of the proposed stormwater facilities. · Core Requirement 2: Off-site Analysis A Level 1 downstream drainage analysis is presented in Section 3. Core Requirement 3: Runoff.Control Level 2 RID standards are required for the site: Core Requirement 4: Conveyance System The onsite stormwater conveyance system and offsite improvements will be designed to convey the 25-year storm. Core Requirement 5: Erosion/Sedimentation Control Plan ,..-:···;_::: : Proposed erosion/sedimentation.control procedures are described in Section 8. An erosion/sedimentation control plan (ESCP) will be developed for the project during engineering design. · · · Core Requirement 6: Mainteiiaiicea~d Operation The proposed systems for managing storm'Yater will be maintained and operated by King County. Recommended maintenance activi_ties are provided in Section 1 O. . . -' . - Core Requirement 7: Bonds and I.ial>iii{ · .. Bonds and liability requirements will be de~eloped for the project during engineering design (Section 9). 2-1 EvendeJI Plat Preliminary TIR-June WO/ 1. 1 .. ' Core Requirement 8: Water Quality As described in Section 5.E, basic water quality standards apply to the site. A basic wetpond will provide water quality treatment for stormwater collected from the site's east basin. A biofiltration swale will provide water quality treatment for stormwater collected from the site's west basin. Alternatively, a wetvault may be used to treat stormwater collected from the site's west basin. A small wetvault will provide water quality treatment for stormwater collected a portion of road improvements along SE 136th Street. Special Requirement 1: Other Adopted Area-Specific Requirements The site is within the Cedar River Basin. Basin-wide requirements have been recommended by the Lower Cedar River Basin and Nonpoint Action Plan that apply to the site. These requirements are covered by the 1998 King County Surface Water Design Manual Applications Maps. Special Requirement 2: Delineation of 100-Y ear Floodplain The site is not within a 100-year floodplain. Special Requirement 3: Flood Protection Facilities The project does not contain nor is it adjacent to a flood protection facility. Special Requirement 4: Source Controls Source controls are not proposed for the development. Special Requirement 5: Oil Control The proposed development does not meet the definition of a high-use site requiring oil control. 2-2 Evendell Plat Preliminary DR-June 2001 ' I I I 3. Offsite Analysis The site and project area are in two separate basins. The majority of the site is in the easterly basin. Topography in this basin slopes primarily from the northwest to the southeast towards 1601h Avenue SE. A smaller portion of the site flows the west. This includes the northwest and southwest comers of the site, as well as a portion of proposed road improvements along SE 136th Street. These portions of the site flow to the west towards 156th Avenue SE. A downstream drainage analysis for the site, including drainage routes along both 1601h Avenue SE and 1561h A venue SE, is presented in this section. The drainage courses from the site were assessed on O 1/05/01. Moderate rainfall occurred during the morning prior to the site visit. The downstream conveyance system is described below and illustrated in Figure 5. Further descriptions of downstream structures are summarized in Table 1. Upstream Drainage Drainage from an approximately 0.94-acre tributary subbasin adjacent to the site's western boundary sheet flows onto the site's easterly basin (Figure 3). Runoff from areas north of the site is collected in the roadside ditch along l Ss'h Avenue SE (Location 2 in Figure 5). Runoff collected in the ditch on the west side of 1581h Avenue SE is conveyed to the east through a 12- inch diameter culvert (Location 1) under the cul-de-sac of 158th Avenue SE. The culvert at Location I also conveys drainage from a section of ditch along the north side of SE 1361h Street (Location 30). The 12-inch diameter culvert discharges to an earth-lined ditch on the site's north boundary (Location 3, Photo 3 in Appendix A.I). Segments of the ditch show signs of minor erosion. The northerly ditch also collects runoff from the roadside ditch on the east side of 158th A venue SE and from properties to the north. The vegetation and dimensions of the northerly ditch change as it proceeds from west to east (Locations 4 and 5). At the northeast corner of the site, a ditch on the west side of 160th Avenue SE joins the system. The system subsequently jogs around a utility box (Location 6). The ditch continues along the east boundary of the site (Location 7). No scouring or erosion was observed in the grass-lined ditch along this segment. The road embankment on the west side of 160th Avenue SE is steep, but stable. A side channel from the onsite wetland merges with the roadside ditch at Location 8. (Photo 4 in Appendix A. I). A small amount of flow was observed exiting the wetland at the time of the site visit. The ditch continues along the east boundary of the site to the site's southeast comer. Downstream Drainage Course -1601 h Avenue SE Upon leaving the site's southeast comer, the grass-lined ditch continues in a southerly direction through 12-inch diameter driveway culverts (Locations IO through 13, Photo 5 in Appendix A. I). At a distance of about 660 feet from the site, a 12-inch diameter concrete pipe conveys drainage to the east side of 160th Avenue SE (Location 14). The site comprises approximately 17 percent of the tributary basin area at this point in the drainage system. Drainage is then conveyed through a 24-inch diameter CMP driveway culvert with a crimped end (Location 15). From Location 15, drainage is conveyed through a short section of ditch with accumulated sediment 3-1 Ew.ndeJJP/at Preliminary TIR-June 2001 (Location 16). At a distance of about 860 feet from the site, drainage flows through an 18-inch diameter pipe at the residence of 14028 -1601h Avenue SE (Location 17). A past drainage problem (Drainage Complaint No. 97-0423) was reported at this location. The complaint was not available but was related to overflow from the roadside ditch (Appendix A.2). The 18-inch diameter pipe discharges to an earth-lined section of ditch (Location 18). Minor erosion was observed at the outlet of the 18-inch diameter pipe. At a distance of about 1,000 feet from the site, drainage flows away l 60'h Avenue SE to the east, among trees on a forested parcel (Location 19). The channel is somewhat flat and braided after leaving the roadside ditch and passes through a ponded area (Location 20). The channel then becomes more well-defined (Location 21) and enters a 12-inch diameter pipe (Location 22) located near a horse corral. Drainage is then conveyed through a 12-inch diameter driveway culvert (Location 23) and then to an open channel. The open channel flows along the north boundary of residential Jots that are along SE 142nd Place. A segment of the channel has been reinforced with concrete blocks (Location 24). Drainage then enters an 18-inch diameter pipe that has a trash rack and concrete headwall inlet (Location 25). At Location 26, the channel turns to the south and has significant bank erosion at the bend. The site comprises approximately 9 percent of the tributary basin area at this point in the drainage system. The channel then flows down the hill (Location 27) towards SE 144th Street. A past drainage problem (Drainage Complaint No. 97-0206) was reported at Location 25 (Appendix A.2). The resident at 16046 -SE 142nd Place has had problems from runoff in the channel along his property. The 18-inch diameter pipe has likely been installed since the complaint was filed to reduce groundwater seepage from the ditch that was apparently compromising the performance of the homeowner's onsite sewage treatment system. The homeowner also stated in the complaint that he maintains the ditch long the north and east boundaries of his property by removing accumulations of debris and sediment. King County investigated the problem for the Neighborhood Drainage Assistance Program. Downstream Drainage Course -1561b Avenue SE A break in grade approximately 250 feet west of the intersection of SE 136th Street and!58th Avenue SE divides surface water flow to the east and west. From the grade break, drainage flows west along a shallow grass-lined ditch along the north side of SE 136th Street (Location 31 ). Road improvements end about 375 feet west of 158th Avenue SE, at which point the roa.dside ditch discharges to a grassy area in the road right-of-way (Location 31). There is no distinct flow path in the road· right-of-way and drainage likely reaches the ditch along 156th Avenue SE by sheet or shallow flow. At the intersection of SE 136th Street (Location 33, Photo 6 in Appendix A. I), the earth-lined ditch along 156th Avenue SE flows to the south. At a distance of about 150 feet south of SE l 36'h Street, drainage enters a series of Type I catch basins connected by segments of ditch and 12-inch diameter pipe (Locations 34 through 52). No signs of capacity problems were observed along the drainage route at these locations. At Locations 35 and 3 7, leaves and other debris have accumulated, presenting the potential for plugging downstream sections of pipe. 3-2 Evenddl Plat Preliminary TIR-Jime 2001 At Locations 42 and 43, drainage from SE 138'h Place enters the conveyance system. Runoff from the southeast corner of the site sheet flows towards the backyards of homes at the end of SE 138th Place. Runoff from this area of the site eventually drains to the conveyance system along SE 138th Place. A past drainage problem (Drainage Complaint No. 97-0107) was reported by the resident at 15641 SE 138 1h Place (Appendix A.2). Based on King County's record, the complaint was related to a change in drainage pattern due to a broken culvert at the cul-de-sac (Appendix A.2). At Locations 46 and 47, drainage from SE 139th Place enters the conveyance system. Downstream from Location 52, a grass-lined ditch conveys drainage to the south along a pasture (Location 53). At the lower end of the pasture (Location 54) the ditch flattens and it appears that high flow rates could flow onto a portion of the pasture. At Location 55, drainage enters a 12- inch diameter pipe. A past drainage problem (Drainage Complaint No. 97-0318) was reported at Location 55 by the resident at 14038 56'h Avenue SE (Appendix A.2). The complaint is a claim and was not available from King County. Based on King County's record, the complaint was related to flooding due to a plugged culvert (Appendix A.2). Downstream Drainage Complaints Drainage complaints along the downstream system were investigated at King County Water and Land Resource Division. Drainage Complaint Nos. 97-0423, 97-0206, 95-0107, and 97-0318 are along the drainage route and are described in the narrative above. A map showing the locations of residents that filed drainage complaints is provided in Appendix A.2. Copies of registered drainage complaints are listed in Appendix A.2. A summary of the drainage complaints is provided in Table A.I of Appendix A.2. 3-3 Evendeil Plat Preliminary 11R-Jwie 2001 -:~' -.··· ,,_ ·' -~-· ,',i::JI'. -·~. , _,r:;J._ • .. ,:::,-:. _-,;.//~·{·. _.D 'Q_ ' """ ""' "' 'Q S.P. 976093 (2) I i 9' mi Sl;S.fHi77011 j Ill m "61 e . s.P. 480029 .. I ~ e eJ ~· -1 G@~ar :i a/kn :: • -----{----+ ---;.:'.. @) @) @) \!i • • I~ 1: s,2.., 1~•S.E:.~ -135TH' ST.•"' • .. ,. s • 1 11~ 7 l 1·: i 2: • " ;;! 4 ° Cedar River ,,,2 15 ,~ i Ile I Watershed ~ -.. - • ;~ .1 C\ i@' 1 '°I'® Q,., .. .._(p,) q)~~.w.~J ~,' CEN,igs . ~N·,-\ ·~® \_ .u,,., 0 ". ( ~_EN TON _AVE.l $11 I ;t: c = e -· 40 I na 11. n" ""' ~ s:tz.! •ST """i3GTH ST. -f-+-Nor tl1J i~A@._ ~i 8 ,~ I. e iJl1 Q , ® *· 6) '. I~ •. ' . '1 . I ~ (3s , ~1 ~ ~ \ ,, I : f C CRE ~FIVE ~ :ii a ~~A -" -~ c1 ~ E ~ ~ ·J11trf31,, ,,g,11) r... ,, . I I j :: ~~ \. S.P. 8781:13 ~ ~ •. l' M- -f.[, '. (· . ..... ' """ I I SITE I \ : . 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' 143RD ST 8 '. ,,.,. )o' ..... *0 :ii -. . · -.. "' ~ 111,rru, 4 S • ''·-:-··,· M7 ULU 11Q.•1 ...... , ll(lil7 ,,,_ -;,oJ, ''.~'I -II: (I) (U. r-,.... PL1 ~ 0 6, ... ~ 1 -c ' R O l L N ) C I " N · 1 0. ~ 2 ' ___ ,,, ' ""' "' .I a ".',. i .\ ' ' -• : ' ' ~ ' ~ ' : .? ' ,:•J, '\ ~ .. ' Y---~~ ,1210,~ o.~1 5:'" :[i ~: •I I ® ' @ ® """ ® @ ® ' ' ' , .. ~ .... • z s:r·· ~· oo s / ,g5 ii' ~ " ~ ~ : n ·. ; a \ ~ , ~ \j !31 131 I I ~ -~ ii "(JlU i ~ !iii Ac ~ ~1S11 ' Cf@! 0 I< ~ la 1 ,l::l 8! J I I -J @-~ · @ . ><~ , .. " ~ I .; -·• .,_' -_.. "' .. _ -·· ~ , ------.i::.: .. ;.·. •.,, . ... s -~' -. ~ ••• -.. "'"'--J. --,; y· - --.l!.~E--i· -·-· -· -,_ · -. -· -· -· -· _-:=._ · -·,o_·.::S~E::.:.__·::::_·2{L.-,·,-:.I~ 44..:T.:..H:_._· =--·--· ::·.,,ii.cS.,T:-~-. -· -. -. -, --· 23 i t {N.L.SHULT~RD.) !JOT DEEOEO fJ,!! ' ' _ I • .. •. . .. . • . LEGEND Culvert Ditch Catch Basin yf',i,:.,· ,' /,,.)_ H iii!' Sheet Flow Location ID 11~0201\lJ C~IQ!~lcClfl.ll'IQ, I" .1 ~ ® SCALE: 1" = 300' rp Tl11.E Figure 5. Downstream Conve PAGE 3-4 DATE 6/11/01 = C7. Table 1. Description of Downstream Conveyance System Basin: Easterly basin draining to 1601 • Ave SE (including upstream areas) Site Visit on 01/05/01 Weather: Rain.l:'. 1~,{a.i/,g~,, -.-. ··· J)rlliil1jge .. · .. · • ;,\,J?f,j~age ... ·.. . ... Existi~g .· :, .. Qbserv,11ti?n(of}".'i~J,f ~w·Kll);:C · • Component Type,, •\ Component Problems · Inspector;Resource;t 1!lr~Jtltr \ Nanie/aitd ~ize '. ··,. ?r~rrlg.~tj.?n '. ... ,;)/ ~fJTui~ttt!tilifl rlil~~~~i i~1:!1~1i"l~1x '(.~~-~~~: ·,<E[·J};,;,:n: ~;;~~.:i}l~!~~!:\11 I~ii!rttf'i~I 56 58 2 3 4 5 Sheet flow I Pasture ar_ea drains I 2 j 'Yest boundary of towards site site Sheet flow 12-inch diameter CP Length= 90' Roadside ditch Width: 1.5' Depth: 2' Side slol'_e: 2: I North boundary ditch Width: 1.5' Depth: 1.5' Side slope: I: I North boundary ditch Width: 1.5' Depth: 3.0' Side slope: 2: l North boundary ditch Width: 2.0' Depth: 3.0' Side slope: 2: I Forested area I I I South portion of HW=I' Earth-lined ditch; east side of 1581h Avenue SE Earth-lined ditch Grass-lined ditch w/ briers Earth-lined ditch 2 4 3 2 2 site Northwest comer of site North of site I North boundary of site I North boundary of site I North boundary of site I Minor erosion I Somewhat undulating topography; runoff from south boundary of site flows south Conveys drainage from west ditch of 158th Avenue SE I Collects runoff from roadside ditches along 158th Avenue SE and areas to north of site Collects runoff from areas to north of site Collects runoff from areas to north of site Table 1 ( continued) Basin: Easterly basin draining to 160" Ave SE i~?~ti,~~i . . Drainage . . · ·.·.•·. l)rainage ·. ;ip;),{; ····Component Type, /i Component " ·::;,l; Name, and ~ize C;:{t1J;{y3rtion ·. 'ii.F, Type: sheefflow, swale, .. · ·, , •... ,idrairiage basiri, ·. · ~{~It --~run, cbanil~(PiPe:">---i : -~,y~g~~<1~~&,yeri;~_Cpth, f::·I&J?f ;' siZe: di8IlletCI'i: ~4th__~--::i.'/fu>~.bf:SCiisitiVe· area· . 6 I North boundary ditch I Dense briars 7 8 9 10 11 12 Width: 2.0' Depth: 3.0' Side slope: 2:1 Roadside ditch Width: 1.5' Depth: 2' Side slope: LS: I Side charmel from onsite wetland Width: 2' Depth: 1.5' Side slope: 2: 1 Roadside ditch Width: 1.5' Depth: 2' Side slope: 3:1 12-inch diameter CP Grass-lined ditch; west side of 158th Avenue SE Wetland Grass-lined ditch HW=l' Roadside ditch I Grass-lined ditch Width: 2' Depth: 1.5' Side slope: 3:1 12-inch diameter CMP I HW=l.5' I I Slope ):(%) 3 4 0.5 3 2 3 2 Disiance from Site Dischafge .. -· :-,-~:-';(?./;/· Existing Problems Potential Problems 1/4 mile=l .• 3. 2_0·ft···.-. r .. ·•.· constrict(ons, unde~ cap~city, pondmg, ·.,. (FI)\::\{YI'•·• overtoppmg, scounng, banksloughmg, · -· · .. ·· ··· ·· · sedimentation. incision, other .erosion Northeast comer of site East boundary of site No scouring or erosion; road embankment is steee but stable I East boundary of I None site East boundary of site 40 60-400 400 None I Observations of Field Inspector, Resoui}e{ R~:;:;:~tr;W;\;I~ tributary area, HkeUhood of : · · proble~)>.f ~~iJf{{Ji pathways, poti:iitial impacts' Collects runoff from areas to north; ditch jogs around utility box; ditch from west side of 160th Avenue SE _joins in I SmaU amount of flow observed v Table 1 ( continued) Basin: Easterly basin draining to 160" Ave SE lliltb~~;1~·: ~t~~~'.'A.. r~~~~f ,r':.~;r.r:J,, i, a~i(!f ~1 fii{fi'tl'.1 :'~}!Ji:f'~\}l Hli~~!~·:: 11lfI~l3,J,~1~;0i )(/tfliti~i!~t°$il>·Ii? 1~~~itfifi; 13 Roadside ditch Grass-lined ditch 3 420-660 Width: 2' 14 15 16 17 18 19 Depth: 1.5' Side slope: 2: 1 12-inch diameter CP Length= 40' HW=l.5' 24-inch diameter CMP I HW=l' Length= 20' Roadside ditch I Grass-lined ditch Width: 2' Depth: 1.5' Side slope: 2:1 18-inch diameter CMP I HW=l' Length= 80'. Roadside ditch I Earth-lined ditch Width: 3' Depth: 3' Side slope: 2:1 Braided channel I Forested 3 660 2 780 3 820-860 3 860 2 950-1,000 I 1,000-1, 100 Downstream end of culvert is crimped Some sediment at culverts Past drainage problem reported at this location; See Drainage Complaint No. 97-0423 Minor erosion at outlet of IS-inch diameter CMP Culvert crosses from west to east side of road Water flows east among trees Table 1 ( continued) Basin: Easterly basin draining to 160" Ave SE w?ffl;¥1~~I~JifJ1!~!~!~~~;~}l~~;['~:'1t1r,:~:~X~§:ffl ~.,f!~ ::~~~;~~~ r;~R!l~jt~cBJ;~;·,~~:1;~~~4t£~ti~ i\~I,£i:ii~~]g~~~~1·~ ~l:~;~;x~it;~1 20 Ponded area Forested, potential 0.5 I, 100-1,200 I Flow path through wetland area middle of ponded area 21 22 23 24 25 26 Channel Width: 2.5' Depth: l' Side slope: 2: I 12-inch diameter CMP 12-inch diameter culvert Channel Width: 2.5' Depth: 2.5' Side slope: Vertical 24-inch diameter culvert Channel Width: 3' Depth: 4' Side slope: I: I Earth-lined I 2 I 1,200-1,350 Earth-lined bottom; concrete block walls Earth-lined 1-2 1-2 2 3 I 1,350 I 1,450 I 1,4 70-1,600 1,600 1,660-1, 700 I Water likely backs up under hi flows I Potential overtopping of drivewa Past drainage problem reported at this location; See Drainage Complaint No. 97-0206 Highly eroded banks I Erosion likely to continue I Culvert passes under horse corral Culvert passes under driveway Culvert has trash rack and concrete headwall inlet Table 1 ( continued) Basin: Easterly basin draining to 160" Ave SE liJ~~!ii~f: ~iil~ti1.ifl~f ji[ija';r,;; .:::r.::ttwa,1~1111 1)~~1t}l-'~~~ttt_• '.i~i~~~~'. '11 ihlil:i;[-n{ll r,;.,t}.t:~i~it~~~~ilf t:~~~~!i~~iI 27 Channel Earth-lined 1,700-2,000 Eroded banks Erosion likely to Channel heads down hill Width: 3' continue towards SE 144th Street Depth: 4' Side slope: I: I Table 1 (continued) Basin: Westerly basin draining to 156'" Ave SE i)}]l,0~iii" ~lf''lJif~' "1~&; }f!~fij~f!ff~;' . ;;r,J:;~, 0liil 1¥,~~~iM re)~~~~'" ;i~,~~it~;; rl~f.r~i·~~~r:'! :fi;\~liiw~~;sEi~~r~ 57 Sheet flow Forested area 2 30 31 32 33 34 35 36 Roadside ditch. Width: 1.5' Depth: 1.5' Side slope: 3:1 Ditch Width: 0.5' Depth: 0.5' Side slape: 3:1 Sheet and/or shallow channel Roadside ditch Width: 2' Depth: 3.5' Side slope: 2:1 12-inch diameter CP 12-inch diameter CP 12-inch diameter CP Grass-lined ditch Shallow grass-lined ditch Grass area; no distinct flow path Earth-lined ditch HW=l' HW=l.5' HW=l.5' 2 2 3 5 4 4 4 of site Road improvement along SE 136th Street · Road improvement along SE 136th Street Road improvement along SE 136th Street 0-150 150 220 310 None Upstream end of culvert partially blocked with leaves Flows to east towards Location I Flows to grass area to west in road ROW Access to vacant lot Table 1 ( continued) Basin: 37 38 39 40 41 42 43 44 Westerly basin draining to 156'• Ave SE '.·:,~· Roadside ditch Earth-lined ditch 5 340-470 4-6 inches of Debris has Width: 2' leaves in bottom potential to block Depth: 2.5' of ditch downstream Side slope: 2: I culverts 12-inch diameter CP HW=l' 12-inch diameter CP I HW=l.5' crossing SE 137th Place Type I CB 12-inch diameter CMP in 12-inch diameter N12 out Type I CB -grate inlet 12-inch diameter N12 Type I CB 12-inch diameter N12 Type I CB 12-inch diameter Nl2 Type I CB 12-inch diameter N12 4 4 4 4 4 3 3 470 550 600 660 870 950 1,100 Upstream end of culvert partially blocked with leaves '---./ Table 1 ( continued) Basin: Westerly basin draining to 1561h Ave SE iJ:;Qcatjoa-•--_ Dr'1i11age• _ -__ --,'.\ Qrainage -•------Slope ,:Distaitcefrmn -------ObservationsofEie!dC !1Iiit!'.t ··-J?~f~ij;;,1rfe1[,: ;;f:{ijiij~1[{Jit i -.. --__ -Sjt_e ~isch-'rge ·--.-:. . }l)i ,f1~;&tiiii{il}~~i r!it~~~--:-~=~{&1:!,~!:~1 }~ilSt~~J---·,V+mil~J-~rwJI; :Mi~~;t;a~~~~~,rifi;?t~ii~fi~l~ 45 I 12-inch diameter CP \ \ 2 \ 1,240 \ \ \ Collects runoff from SE from east 13 9th Place 46 I Type I CB -grate inlet 47 48 49 50 51 52 53 54 12-inch diameter Nl2 Ill 12-inch diameter CP out Type I CB :=_grate inlet 12-inch diameter CP from east Type 1 CB -grate inlet 1_2-inch diameter N12 out 12-inch diameter N12 outlet 12-inch diameter CP 12-inch diameter CP Roadside ditch Width: 1.5' Depth: 2' Side sl()Jle:):f / •. ( Roadside ditch HW= I' HW= l' Grass-lined ditch Grass-lined ditch; ditch flattens out 3 3 I 2 3 3 I 3 3 3 2 1,240 1,290 ::::: =r-------, 1,460 I Half-filled with I sediment 1,470 1,520 1,550-1,750 1,750-2,000 I Collects runoff from SE 139th Place Water likely spreads out onto adjacent pasture u Table 1 ( continued) Basin: Westerly basin draining to 156'• Ave SE lil'°ii:J;!~~ii •;~-~~:., . i~~Jli; · :z~::! ~~ti~1 "~~~ii~i:~r t~~u:i J.i~-~~~; ;r~~~~u :;i{{~~1~ii~r:~1· 'i~1t.E~;i;;~~a.r~tfc :'1-~;~~~~1f1f. 55 12-inch diameter CP HW = I' 2 2,000 Past drainage problem reported at this location; See Drainage Complaint No. 97-0318 I 4. :Flow Control and Water Quality FacilityAnalysis and Design· Part A: Existing Hydrology The site consists of two basins, The topography of the east basin generally slopes from the northwest to the southeast (Figure 3). The topography of the west basin generally slopes from the east to the west. Cover types on the site include a single-family residence (Photo I in Appendix A. I), forest (Photo 2 in Appendix A.1 ), and pasture. A Class 2 wetland has been identified in the northeast portion of the site. Cover types and areas used in the stormwater design for existing onsite conditions are summarized in Table 2. Part B: Developed Site Hydrology The proposal for development includes building 75 single-family dwellings on about 12 acres. The proposed site plan is provided in Figure 6. Cover type areas for developed onsite conditions are summarized in Table 2. Under developed conditions, the developed portion of the site, including offsite road improvements, will consist of 4.53 acres of grass and 7 .23 acres of impervious area. Under developed conditions, stormwater from the site and road improvements will be collected and treated onsite to basic water quality standards. Stormwater will be managed separately in the east and west basins. In the east basin, stormwater from the site and a portion of improvements along SE 136th Street will be collected and managed in an onsite combined wetpond/detention pond. The outfall of the pond will discharge to the drainage ditch along the west side of 160th A venue SE. Stormwater from a 0.33-acre portion of SE 136'h Street will bypass the onsite stormwater facility, but will be treated to basic water quality standards with a small wetvault located near the intersection of SE 136th Street and 160th Avenue SE. The stormwater pond in the southeast comer of the site will be designed using a downstream point-of-compliance to account for the bypass from SE 136th Street. In the west basin, stormwater.from the site and a portion of improvements along SE 136'h Street will be collected and managed in an onsite detention vault and subsequently treated by a biofiltration swale. Stormwater from a 0.19-acre portion of SE 13 61h Street will bypass the onsite stormwater facility. The stormwater vault in the southwest comer of the site will be designed using a downstream point-of-compliance to account for the bypass from SE 1361h Street. Runoff from the existing impervious area of0.16 acre on SE 1361h Street will be treated onsite in lieu of the bypass. · · 4-1 EvendeJJ Plat Preliminary 11R-June 2001 Table 2. Existing and Developed Site Basin Conditions . Existing Conditions Subhasins KCRTS Till-forest Till-pasture Wetland Ti/I-grass Imperv Basin (AC) (AC) (AC) (AC)· (AC) East Basin exeast Site 7.54 · 1.74 --- SE 136th Street Improvements -0.47 --0.09 Subtotal 7.54 2.21 --0.09 West Basin exwest Site 0.44 1.12 --- SE 136th Street Improvements -0.29 0.07 Subtotal 0.44 1.41 --0.07 Grand Total 7.98 3.62 --0.16 Developed Conditions Suh basins KCRTS Ti/I-forest Till-pasture Wetland Till-grass lmperv Basin (AC) (AC) (AC) (AC) (AC) East Basin deveast Lots 3.79 4.82 RID 0.16 0.66 SE 136th Street Improvements -0.56 Subtotal ---3.95 6.04 West Basin devwest Lots 0.58 0.73 RID 0.10 SE 136th Street Improvements -0.36 Subtotal ---0.58 1.19 Grand Total ---4.53 7.23 Note: 0.19 acre of impervious of SE 136 Street improvements bypass the RID facility in the west basin. 0.33 acre of impervious of SE 136 Street improvements bypass the RID facility in the east basin. 4-2 Total (AC) 9.28 0.56 9.84 1.56 0.36 1.92 11.76 Total (AC) 8.61 0.82 0.56 9.99 1.31 0.10 0.36 1.77 11.76 ) Part C: Performance Standards A summary of flow control, conveyance, and water quality treatment performance standards for the project is presented in Table 3, below. Table 3. Summary of Performance Standards Cate2orv Performance Standard Source Flow Control • Level 2 RID • 1998 King County Surface Water Design Manual; Applications Map Conveyance System • Provide conveyance for • Surface Water Design Capacity developed 25-year storm Manual Section 1.2.4.1 Water Quality • Basic water quality treatment • Surface Water Design Treatment Menu using a wetpond in the east Manual Section 1.2.8.1; basin and a biofiltration swale Applications Map or wetvault in the west basin Source Control • None proposed Oil Control • The site does not meet the • Surface Water Design definition of a high-use site Manual Section 1.3.5 4-3 Evendell Plat Preliminary 11R-Jw,e 200/ Part D: Flow Control System KCRTS was used to design the proposed stormwater facilities. Procedures and design criteria specified in the 1998 King County Surface Water Design Manual were followed for hydro logic modeling. Descriptions of the stormwater systems and details of the design analysis are provided below. A plan view of the stormwater systems is provided in Figure 6. For stormwater facility designs, the reduced KCRTS time series data set was used for the Sea- Tac rainfall region with a correction factor of 1.0. Documentation of the KCRTS input and output including descriptions of executable files, reservoirs, and times series is provided in Appendices C and D. Under developed conditions, stormwater from the site and offsite road improvements will be collected and treated onsite to basic water quality standards. A combined wetpond/detention pond will be used to manage runoff in the easterly basin. A small wetvault will provide water quality treatment to a portion of SE 136 1h Street that bypasses the stormwater facility. A biofiltration swale will be used to manage runoff in the westerly basin. Level 2 RID standards are required by the King County Flow Application Maps and recommended by Lower Cedar River Basin and Nonpoint Action Plan. The natural discharge locations from the site will be maintained at the outlet of the proposed stormwater facilities. Stormwater from the development in the easterly basin will be managed with a combined wetpond/detention facility. Stormwater from the development in the westerly basin will be managed with a detention vault facility followed by a biofiltration swale. Level 2 RID standards are proposed for both facilities. The storm water facilities shown in Figure 6 meets Level 2 RID criteria and basic water quality requirements. Flow duration curves at the downstream point-of- compliance are provided in Figures 7 A and 7B. Peak flow rates for the downstream point-of-. compliance, under existing and developed site conditions follow Figures 7 A and 7B. The downstream point-of-compliance includes runoff from portions of SE 1361h Street that bypasses the stormwater facilities. The duration curves and peak flow rates; shown for existing and developed conditions, indicate that Level 2 RID criteria are met. The stormwater facility in the east basin requires approximately 117,770 cubic feet of live storage, excluding a factor of safety, to meet Level 2 RID standards. The stormwater facility in the east basin requires approximately l 7,92lcubic feet of live storage, excluding a factor of safety, to meet Level 2 RID standards. A factor of safety of 5 to IO percent will be added to the final design volume. Part E: Water Quality System Basic water quality standards apply to the site. A basic wetpond will provide treatment for the site's easterly basin. A small wetvault will provide treatment for a portion of road improvements along SE 1361h Street that bypasses the easterly stormwater facility. A biofiltration swale will provide treatment for the site's westerly basin. Alternatively, a wetvault may be used to treat storm water collected from the site's west basin. A treatment trade is proposed for storm water collected from the road improvement area along SE 136th Street in the site's westerly basin to account for a small area of the road improvement that bypasses the westerly stormwater facility. 4-4 Evenddl Plat Preliminary TIR-June 2001 Runoff from an area of existing pollution generating impervious surfaces equivalent to the area bypassed will be collected from SE 136th Street and treated onsite. · The required wetpool volumes for the treatment facilities were determined using equations provided in Chapter 6 of the 1998 Surface Water Design Manual. Basin areas, annual runoff volumes, Vb/Vr ratios, and required volume for the wetpond are given in Table 4. 4-5 EvendeJJ Plat Preliminary 11R-June 201)/ D D '· !~.-~·~·-·..;.;.,·..:.... • I • I • I • I - 'deveast/ I . SE 138TH YtAJfB QI !Al ny \IAHf:l- 1 \ un, x JO'L x 5-S'D QNSIDE DIM.) TOP OF Vl<.ILT-482-" • • I . RA1tR SURFICE-482.0 Ill ( . ear. DET.-4n .D )' • . )r __.-/ -~-----I• , --~l§.'!}1J!}.et1;Jt. 1_ 3(!th s~f:t~ ~ g ~· ~~\.E'.;::1-:;~~ ~ )--· ... r-·:-. -·=·-·-·,:'>.-"---... --.~ I 00 ..,, ___ _ . . - 3~·~8 ~ 9~- SJT-D;WESL ·t· . -1. --;; ----/,?,14\,.A{; 4' mbed (t'Jre { 4 V II . 7 Fen l, ....'._!,I -,.~_; i------·--i ·-·-· s ----Y 6 · ; 11 Offsite 4 AC ~ Area= 0.9 ,,lttt,.:" IL_I ""%~ 5'Waod~ ... _J L I I I ----==-1 ~ ~ _J ~ _L __J '_J Lot 7 I Rhse ~ .... I / . -......___ Y ,--.....! / . I -' ..... ~ND & I ~ /. t · . El llITffi-._ , ~ ~ I-. -4.::----t,1_9 AC . ~/~---1 ~-\ ·~c 47 · /i 51 j · i \ \ CtJ /I . ~ ~-\ . -;· -. -i-. . ..L. _.,., ·/. I o, . " ' ·~ . . ./ -"' ! tl _ . _ . _! 43 I 3!___,,, . . 37 '-., / "9-°.....__ "- ~ ~ ~. . . . 0 ' r I · · l _re. 1-·7 1 ! ~ I 41 I 4ifj 1 36 I 35 _/ ·v _ ~ J~--¥~~L~~!_:r~{=.J. ~-/ 34 _I\,. r· . -,; . 1, / r -r--,-y ·, ' _/ : . / ., . . • v 33 '- .~ Fil~u 56 1 75 ! 74 i 13 ,,,>iJ "i-__ ~ ·.,:~1'----/-/ .r--· . ! 32 l /; ': c:-=--~1 iv s1 y-~/-~!11--.-/-:f 30 . ~ -· -_;.-,-· _J .....c ( -I---. -. --1 l:5 l l 29; · /58 i ,59~1 i 71 J ~~1 ___ ,J~ _j_ a ___ / -TE -t-·-.. 7·--1 I / · __ . . ____L._ . ...J 1-8----~ /---·-·'-. ,a;e-! ! !~7~r= 61 y I y 68 I le.. ~ =-~ l80 . 611 , BOT,,(Ef.~ . .,L': _ . ·-;/.· -1_ /-: ~1-f----.:_; i ~-~"j i1~: g / t ,, • ~ PRC11. ~ 37 ·-·-· i _____ 1 . 100 , .S. -SF . .. 83 _i 64 j 65 ,1 ::.A . ' ~ __ =:=2_.1:=1 __ _ ·->.;_,· I~ '-,. --4 / fr {. _.,.. -~. Bar ~~--.--·:--re;.-:: ti;_.... -., . \ f. ast 1·38:!, p1.ree . I ence I . I I 19 · j 21 /. 22 · 23 ~l/f · i · 26 I \ . I I I "" ..., I .~::; '\1-1 , • 't ~I , _____ , ..... s Y\ -L .. -+--_ _j l r-~ . I • I • I • I • I • I • I • I ~ Y'-w :::E w I-I- --0: lllz _J ~j Q _J et: n. __; ' ,~5 w' 0 -<-z ~Ill w :::i; w > i a:: 0 ld 'O I- ~ ~ P.. ::I ' .. ' e I Ill bD i ! ~ .,g ' ' u i!i5 1.;; i:" ., !Bx ii:::c :..: s:f zS: !9_ J...~-.,.. § ' ~i:ili ! ,_, ...,,, I ,.. is 8 i g i I I D . N t!I w 1..:.: o ;:fi ~ I! crs _ V'I ir::r. = !~ io § ~1"1111 3 ~~Q I! ) 'iii u. ~ a, -"' 0:: ~ 0 ii: 0.7 --+--Existing -i3 -Developed 0.6 0.5 0.4 0.3 0.2 0.1 O+------+------+------+------+----...... ---l 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+OO Probability of Exceedence Figure 7A. Flow Duration·Curves for RID -East Basin. Duration curves are shown at the downstream point of compliance in the easterly basin. The pond is designed to meet Level 2 RID standards. 4-7 ) I. I Predeveloped Peak Flow Rates -East Basin Flow Frequency Analysis Time Series File:exeast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0. 64 5 2 2/09/01 18:00 0.891 1 100.00 0. 990 0.200 7 1/05/02 16:00 0.645 2 25.00 0.960 0.517 3 2/28/03 3:00 0. 517 3 10.00 0.900 0.037 8 3/24/04 19:00 0.508 4 5.00 0.800 0.303 6 1/05/05 8:00 0. 457 5 3.00 0.667 0.508 4 1/18/06 20:00 0.303 6 2.00 0.500 0. 457 5 11/24/06 4:00 0.200 7 1. 30 0.231 0.891 1 1/09/08 9:00 0.037 8 1.10 0. 091 Computed Peaks 0.809 50.00 0.980 Developed Peak Flow Rates -East Basin Flow Frequency Analysis Time Series File:poceast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0. 611 2 2/09/01 19:00 1.13 1 100.00 0.990 0.177 7 1/05/02 16:00 0. 611 2 25.00 0.960 0.517 3 3/06/03 20:00 0. 517 3 10.00 0.900 0.182 6 8/26/04 2:00 0. 472 4 5.00 0.800 0.173 8 1/05/05 8:00 0. 214 5 3.00 0.667 0.214 5 1/19/06 2:00 0.182 6 2.00 0.500 0. 472 4 11/24/06 6:00 0 .177 7 1.30 0.231 1.13 1 1/09/08 11: 00 0 .173 8 1.10 0. 091 Computed Peaks 0.955 50.00 0.980 4-8 Evendell Plat Preliminary 71R-June 2001 •• I_ L ·-- , 0.2 -+--Existing --El -Developed 0.18 0.16 0.14 El_ ~ 0.12 ~ Cl) -"' a:: ~ 0 li: 0.1 0.08 0.06 0.04 0.02 0 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+OO Probability of Exceedence Figure 7B. Flow Duration Curves for RID -West Basin. Duration curves are shown at the downstream point of compliance in the westerly basin. The pond is designed to meet Level 2 RID standards. 4-9 Predeveloped Peak Flow Rates -West Basin Flow Frequency Analysis Time Series File:exwest.t~f Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.138 2 2/09/01 18:00 0.235 1 100.00 0.990 0.059 7 1/05/02 16:00 0.138 2 25.00 0.960 0 .129 3 2/28/03 3:00 0.129 3 10.00 0.900 0.024 8 8/26/04 2:00 0.122 4 5.00 0.800 0.074 6 1/05/05 8:00 0.116 5 3.00 0.667 0.122 4 1/18/06 16:00 0.074 6 2.00 0.500 0.116 5 11/24/06 4:00 0.059 7 1. 30 0~231 0.235 1 1/09/08 6:00 0.024 8 1.10 0.091 Computed Peaks 0.202 50.00 0.980 Developed Peak Flow Rates -West Basin Flow Frequency Analysis Time Series File:pocwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.140 2 2/09/01 18:00 0.197 1 100.00 0.990 0.059 8 1/05/02 16:00 0.140 2 25.00 0.960 0.110 4 3/06/03 19:00 0.135 3 10.00 0.900 0.067 7 8/26/04 2:00 0.110 4 5.00 0.800 0.068 6 10/28/04 16:00 0.107 5 3.00 0.667 0.107 5 1/18/06 20:00 0. 068 6 2.00 0.500 0.135 3 11/24/06 4:00 o. 067 7 1. 30 0.231 0 .197 1 1/09/08 9:00 0.059 8 1.10 0.091 Computed Peaks 0.178 50.00 0.980 4-10 Evenddl Plat Preliminary TJR-.lwle 2001 East Basin Residential Lots/Onsite Road 0.00 3.79 4.82 8.61 9,018 3.0 27,053 RID Tract 0.00 0.16 0.66 0.82 1,082 3.0 3,245 SE 13 6th Street Improvements 0.00 0.00 0.23 0.23 353 3.0 1,059 !Total o.ooJ 3.95! 5.71 J 9.66! i 10,452 ! 31,357 I East Basin -SE 136th Street Improvements SE 136th Street Improvements 0.00 0.00 0.33 0.33 5071 3.0 I 1,520 I ._!T_ot_a_l ___ __,_ __ o._00:.J.J __ o;....o.;__o..1.J ___ O.;c.3.c..3 ._I ----'O:..C:.3c.c..J3 ! ~' __ 50_7~' 1,s20 I West Basin* Residential Lots/Onsite Road 0.00 0.58 0.73 1.31 1,368 3.0 4,105 RID Tract 0.00 0.00 0.10 0.10 154 3.0 461 SE 13 6th Street Improvements 0.00 0.00 0.17 0.17 261 3.0 783 i~T_ot_al ___ _._ __ o_.o__.oJ __ o_.5_8..._! ___ 1._oo_,.J __ .c...1.5__.8! l~ __ l,~78_3~! 5,349 i Mean annual stonn = 0.47 * Either a wetvault or biofiltration swale will be used to tre'!lt water in the west basin. 4-11 '. - I •. Stormwater RID System Conveyance The onsite stormwater system will be designed to convey the 25-year peak flow rate for conveyance systems upstream of the stormwater facility. A conceptual design of the conveyance system is shown in Figure 6 of Section 4. 5-1 Evende/J Plat Preliminary 71R-June 2001 6;··•specia!Reports'andStudies· :. A summary of special reports and studies conducted for the Evendell Plat is presented below. Table 5. Summary of Special Reports and Studies Study/Report Geotechnical/soils Wetlands Evendell Plat, King County, Washington. Wetland Delineation and Report Floodplains Groundwater Anadromous fisheries impacts Hydrology Level 1 Downstream Drainage Analysis (Section 3 Evendell Plat Preliminary Technical Information Report) Water quality Structural fill 6-1 Evenddl Plat Preliminary TJR-Jwie 2001 Date Conducted NIA June 2001 NIA NIA NIA January 2001 NIA NIA 9:,:onond Quantities;'FacilifySuminaries; and Declaration of Covenant · A bond quantities worksheet for the project will be prepared during final engineering for the submittal. A summary of onsite conveyance and water quality facilities is given in Figure I 0. None of the facilities will be privately owned or maintained. Therefore a declaration of covenant is not needed. 9-1 Evende/1 Plat Preliminary 11R-June 2001 Figure 10. Flow Control and Water Quality Facility Summary Development: Evendell Plat Date: 6-11-01 Location: King County Township 23N, Range 5E, Section 14 ENGINEER Name: Ed McCarthy Firm: Haozous Eneineerine, P.S. Address: 14816 SE I 16th Street Renton, WA 98059 Phone: (425) 235-2707 Developed Site: 12 Acres Number of detention facilities on site: 1 Combined Wetpond/R/D 1 Vault Downstream Drainaee Basins Lower Cedar River Number & type of water quality facilities on site: _I __ biofiltration swale (regular/wet/ or continuous inflow?) _I __ combined detention/WQ ponds __ flow dispersion trenches ___ c.ombined detention/wetvault ___ compost filter __ filter strip ___ landscape management plan DEVELOPER Name: Mike Romano (representing U.S. Land Develooment, Inc.• Finn: U.S. Land Development Associates, Inc. Address: Clo Centurion Development Services 22617 8th Dr. SE Bothell, WA 98021 Phone:/4251 486-2563 Number of lots: 75 single-family residences Number of infiltration facilities on site: 0 Immediate Major Basin Orting Hills Cedar River __ sand filter (basic or large?) ___ sand filter, linear (basic or large?) ___ sand filter vault (basic or large?) _! __ vault _2 __ energy dissipation structure(s) Basic pond (basic or large?) ___ oil/water separator (baffle or coalescing plate?) ___ catch basin .inserts: Manufacturer __________________ _ ___ pre-settling pond ___ pre-settling structure: Manufacturer __________________ _ __ flow-splitter catch basin DESIGN INFORMATION Easterly Basin SE 136'" Street Westerly Basin /Easterlv Basin) Water Oualitv Desi= Volume (CF) 31,400 5300 Biofiltration Swale Onsite Area (AC) 9.43 0.00 1.41 Offsite Area(AC) 0.56 0.33 0.36 Type of Storage Facility Combined Wetvault Vault Wetpond/R/D Reauired Live StoraQe Volume (CF) 118,000 NIA 18,000 Figure 10 ( continued) DESIGN INFORMATION .. Easterly Basin SE 136"' Street Westerly Basin /Easterlv Basin) Pre developed Runoff Rates 25-year (CFS)** 0.645 0.023 0.138 Post-RID Developed Runoff Rates 25-vear /CFS)** 0.611 0.069 0.140 ** Based on KCRTS I-hour peak rates for the proposed developed area. ) J()/OperationSand Maintenance Manual· · •· The conveyance and water quality facilities for the Evendell Plat will not be privately maintained nor do they contain non-standard features. The table below specifies the maintenance requirements for each component of the storm water facility being constructed. Applicable maintenance requirements, taken from the 1998 Surface Water Design Manual, are referenced to the pages that follow. Table 7. Summary of Maintenance Requirements for Stormwater Facilities Maintenance Requirement • No. I -Detention Ponds • No. 4 -Control Structure Restrictor • No. 5 -Catch Basins • No. 6 -Debris Barriers • No. 10 -Conveyance Systems • · No. 13 -Water Quality Facilities -Wetponds • No. 13 -Water Quality Facilities-Wetvaults • No. 13 -Water Quality Facilities -Biofilration Swales ]()..] Evendell Plat Preliminary 11R-June 2001 0. 1 -DETENTION PONDS General Trash & Debris Poisonous Vegetation Pollution Unmowed Grass/ Ground Cover Rodent Holes Insects Tree Growth Side Slopes of Pond Erosion Storage Area Sediment Pond Dikes Settlements Emergency Rock Missing Overflow/Spillway Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Any poisonous or nuisance vegetation which may constitute a hazard to County personnel or the public. Oil, gasoline, or other contaminants of one gallon or more Q.! any amount found that could: 1) cause damage to plant, animal, or marine life; 2) constitute a tire hazard; or 3) be flushed downstream during rain stonns. If facility is located in private residential area, mowing is needed when grass exceeds 18 inches in height. In other areas, the general policy is to make the pond site match adjacent ground cover and terrain as long as there is no interference with the function of the facility. Any evidence of rodent holes if facility is acting as a dam or benn, or any evidence of water piping through dam or berm via rodent holes. When insects such as wasps and hornets interfere with maintenance activities. Tree growth does not allow maintenance access or interferes with maintenance activity (i.e., slope mowing, silt removal, vactoring, or equipment movements}. If trees are not interfering with access, leave trees alone. Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Accumulated sediment that exceeds 10% of the designed pond depth. Any part of dike which has settled 4 inches lower than the design elevation. Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. /0-2 Trash and debris cleared from site. No danger of poisonous vegetation where County personnel or the public might normally be. (Coordination with Seattle-King County Health Department) No contaminants present other than a surface film. (Coordination with Seattle/King County Health Department) When mowing is needed, grass/ground cover should be mowed to 2 inches in height. Mowing of selected higher use areas rather than the entire slope may be acceptable for some situations. Rodents destroyed and dam or berm repaired. (Coordination with Seattle/King County Health Department) · Insects destroyed or removed from site. Trees do not hinder maintenance activities. Selectively cultivate trees such as alders for firewood. Slopes should be stabilized by using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. Sediment cleaned out to designed pond shape and depth; pond re- seeded if necessary to control erosion. Dike should be built back to the design elevation. Replace rocks to design standards. ::>. 4 -CONTROL STRUCTURE/FLOW RESTRICTOR General Trash and Debris · (Includes Sediment) Structural Damage Cleanout Gate Damaged or Missing Orifice Plate Damaged or Missing Obstructions Overflow Pipe Obstructions Manhole Catch Basin Distance between debris build-up and bottom of orifice plate is Jess than 1-1/2 feet. Structure is not securely attached to manhole wall and outlet pipe structure should support at least 1,000 lbs. of up or down pressure. Structure is not in upright position (allow up to · 10% from plumb). Connections to outlet pipe are not watertight and show signs of rust Any holes-other than designed holes-in the structure. Cleanout gate is not watertight or is missing. Gate cannot be moved up and down by one maintenance person. Chain leading to gate is missing or damaged. Gate is rusted over 50% of its surface area. Control device is not working properly due to missing, out of place, or bent orifice plate. Any trash, debris, sediment, or vegetation blocking the plate. Any trash or debris blocking (or having the potential of blocking) the overflow pipe. All trash and debris removed. Structure securely attached to wall and outlet pipe. Structure in correct position. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Structure has no hates other than designed holes. Gate is watertight and works as designed. Gate moves up and down easily and is watertight. Chain is in place and works as designed. Gate is repaired or replaced to meet design standards .. Plate is in place and works as designed. Plate is free of all obstructions and works as designed. Pipe is free of all obstructions and works as designed. See "Closed Detention SystemsM Standards No. 3 See MClosed Detention Systems' Standards No. 3 See MCatch Basins· Standards No. 5 See 'Catch Basins· Standards No. 5 10-3 'O. 5 -CATCH BASINS Structure Damage to Frame and/or Top Slab Cracks in Basin Walls/ Bottom SedimenU Misalignment Trash or debris of more than 1/2 cubic foot which is located immediately in front of the_ catch basin opening· or is blocking capacity of the basin by more than 10% Trash or debris (in the basin) that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking more than 1/3 of its height. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). Deposits of garbage exceeding 1 cubic foot in volume Comer of frame extends more than 3/4 inch past curb face into the street (If applicable). Top slab has holes larger than 2 square inches or cracks wtder than 1/4 inch (intent is to make sure all material is running into basiri). Frame not sitting flush on top slab, i.e., separation of more than 3/4 inch of the frame from the top slab. Cracks wider than 1 /2 inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer than 1 foot at the joint of any inlet/ outlet pipe or any evidence of soil particles entering catch basin through cracks. Basin has settled more than 1 inch or has rotated more than 2, inches out of alignment. 10-4 No Trash or debris located immediately in front of catch basin opening. No trash or debris in the catch basin. Inlet and outlet pipes free of trash or debris. No dead animals or vegetation present within the catch basin. No condition present which would attract or support the breeding of insects or rodents. Frame is even with curb. Top slab is free of holes and cracks. Frame is sitting flush on top slab. Basin replaced or repaired to design standards. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Basin replaced or repaired to design standards. 0. 5 -CATCH BASINS (CONTINUED) Catch Basin Cover !_adder Metal Grates (If Applicable) Vegetation Pollution Cover Not in Place Locking Mechanism Not Working Cover Difficult to Remove Ladder Rungs Unsafe Trash and Debris Damaged or Missing. Presence of chemicals such as natural gas, oil and gasoline. Vegetation growing across and blocking more than 10% of the basin opening. Vegetation growing in inlet/outlet pipe joints that is more than six inches tall and less than six inches apart. Nonflammable chemicals of more than 1/2 cubic foot per three feet of basin length. Cover is missing or only partially in place. Any open catch basin requires maintenance. Mechanism cannot be opened by on maintenance person with proper tools. Bolts into frame have less than 1/2 inch of thread. One maintenance person cannot remove !id after applying 80 lbs. of lift; intent is keep cover from sealing off access to maintenance. Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Grate with opening wider than 7/B inch. Trash and debris that is blocking more than 20% of grate surface. Grate missing or broken member(s) of the grate. NO. 6 DEBRIS BARRIERS (E.G., TRASH RACKS) Metal Trash and Debris Damaged/ Missing Bars. Bars are bent out of shape more than 3 inches. Bars are missing or entire barrier missing. Bars are loose and rust is causing 50% deterioration to any part of barrier. 10-5 No vegetation blocking opening to basin. ~o vegetation or root growth present. No pollution present other than surface film. Catch basin cover is closed Mechanism opens with proper tools. Cover can be removed by one maintenance person. Ladder meets design standards and allows maintenance person safe access. Grate opening meets design standards. Grate free of trash and debris. Grate is in place and meets design standards. Barrier clear to receive capacity flow. Bars in place with no bends more than 3/4 inch. Bars in place according to design. Repair or replace barrier to design standards. Pipes Open Ditches Catch Basins Debris Barriers (e.g., Trash Rack) Sediment & Debris Vegetation Damaged Trash & Debris Sediment Vegetation Erosion Damage to Slopes Rock Lining Out of Place or Missing (If Applicable). Accumulated sediment that exceeds 20% of the diameter of the pipe. Vegetation that reduces free movement of water through pipes. Protective coating is damaged; rust is causing more than 50% deterioration to any part of pipe. All vegetation removed so water flows freely through pipes. Pipe repaired or replaced. Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%. Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Accumulated sediment that exceeds 20 % of the design depth. Vegetation that reduces free movement of water through ditches. See "Ponds~ Standard No. 1 Maintenance person can see native soil beneath the rock lining. See ~catch Basins: Standard No. 5 See "Debris Barriers~ Standard No.6 /0-6 Trash and debris cleared from ditches. Ditch cleaned/ flushed of all sediment and debris so that it matches design. Water flows freely through ditches. See ·ponds· Standard No. 1 Replace rocks to design standards. See "Catch Basins· Standard No.5 See ·Debris Barriers" Standard No.6 0. 13-WATER QUALITY FACILITIES Trash and Debris lnleU Outlet Pipe Sediment Accumulation in Pond Bottom Oil Sheen on Water Erosion Settlement of Pond Dike/ Berm Rock Window Overflow Spillway Vegetation such as grass and weeds need to be mowed when it starts to impede aesthetics of pond. Mowing is generally required when height exceeds 18-inches. Mowed vegetation should be removed from areas where it could enter the pond, either when the pond level rises, or by rainfall runoff. Accumulation that exceeds 1 CF per 1000-SF of pond area. lnleU Outlet pipe clogged with sediment and/ or debris material. Sediment accumulations in pond bottom that exceeds the depth of sediment zone plus 6-inches, usually the first cell. · Prevalent and visible oil sheen. Erosion of the pond's side slopes and/ or scouring of the pond bottom, that exceeds 6-inches, or where continued erosion is prevalent. Any part of these components that has settled 4- inches or lower than the des~n elevation, or inspector determines dike/ berm is unsound. Rock window is clogged with sediment. Rock is missing and soil is exposed at top of spillway or outside slope. 10-7 Vegetation should be mowed to 4 to 5 inches in height. Trees and bushes should be removed where they are interfering with pond maintenance activities. Trash and debris removed from pond. No clogging or blockage in the inlet and outlet piping. Removal of sediment from pond bottom. Removal of sediment from pond bottom. Slopes should be stabilized by using proper erosion control measures, and repair methods. Dike/ berm is repaired to specifications. Window is free of sediment and debris. Replace rocks to specifications. ,-iO. 13-WATER QUALITY FACILITIES Wetvaults tM 'iiiterfan··· ?~~~~~~~i\\:i'Nii¥)t!;. Wetvault Trash/ Debris Accumulation Sediment Accumulation in Vault Damaged Pipes Access Cover Damaged/ Not Working Vault Structure Damaged Baffles Access Ladder Damage Trash and debris accumulated in vault, pipe or Trash and debris removed from inlet/ outlet, (includes floatables and non-vault. floatables), Sediment accumulation in vault bottom that exceeds the depth of the sediment zone plus 6- inches. lnleV outlet piping damaged or broken and in need of repair. Cover cannot be opened or removed, especially by one person. Vault: Cracks wider than 1/2-inch and any evidence of soil particles entering the structure through the cracks, or maintenance/ inspection personnel determines that the vault is not structurally sound. Baffles corroding, cracking, warping and/ or showing signs of failure as determined by maintenance/ inspection staff. Ladder is corroded or deteriorated, not functioning property, missing rungs, has cracks and/ or misaligned. 10-8 Removal of sediment from vault. Pipe repaired and/ or replaced. Pipe repaired or replaced to proper working specifications. No cracks wider than 1/4-lnch at the joint of the inlet/ outlet pipe. Vault is detennined to be structurally sound. Repair or replace baffles to specifications. Ladder replaced or repaired to specifications, and is safe to use as determined by inspection personnel. . _ .J. 13-WATER QUALITY FACILITIES Biofiltration Swales Biofiltration swale Sediment Accumulation on Grass Layer Vegetation Inlet Outlet Pipe Trash and Debris Accumulation Erosion/ Scouring When the grass becomes excessively tall (greater than 10-inches); when nuisance weeds and other vegetation starts to take over. lnleV outlet pipe clogged with sediment and/ or debris. Trash and debris accumulated in the bio-swale. Where the bio-sw"ale has eroded or scoured the bottom due to flow channelization, or higher flows. 10-9 No sediment deposits on grass layer of the bio-swale, which would impede filtration of runoff. Vegetation is mowed or nuisance vegetation is eradicated, such that flow not impeded. Grass should be mowed to a height between 4 inches and 9 inches. No clogging or blockage in the inlet and outlet piping. Trash and debris removed from bioswale. Bioswale should be re-graded and re-seeded to specification, to eliminate channeled flow. Overseeded when bare spots are evident. I t I 11. •References King County Department of Natural Resources, 1998. King County Surface Water Design Manual. Seattle. King County Department of Natural Resources, 1997. Lower 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. 11-1 Evendell Plat Preliminary 17R-June 2001 '. .· •Appendix.A: D.ownstream SyMelii Appendix A.I Photographs of the Downstream System Appendix A.2 Drainage Complaints Appendix A.3 Orting Hills Subbasin Map Evenddl Plat Preliminary 77R-.lune 2001 05/10/2004 15:08 2535390514 SDUNDBUILT HOMES PAGE 21 habitat type with the greatest number of observations noted along the edge between this upland forested habitat type and the mixed wetland areas. This habitat type also appeared to provide cover to many species that also used the adjacent areas, particularly the residential areas. A number of nests were observed onsite and appeared to have been used during the 2000 breeding season. A limited number of stumps and snag trees are present within this plant community. These stumps and snags appeared well utilized as feeding areas by a wide variety of avian species, particularly hairy woodpeckers, creepers, and Northern flicker. A few of these snags also exhibited a limited use by pileated woodpecker (Drpocopus pileatus). Mammal species observed within this habitat type included deer mouse (Peromyscus maniculatus), shrew (Sorex spp.), opossum (Didelphis virginianus), Douglas squirrel (Tamiasciurus douglasm, mountain beaver (Ap/odontia rufa), raccoon (Procyon lotor), and black tailed deer (Odocoileus hemionus). Freshwater Deciduous Wetland: A deciduous wetland area was identified to pass generally from north to southeast through the northeastern portion of the project site. This wetland represented less than 5% of the total project area, had been greatly modified by prior forest harvest activities, and was dominated by a young mixed forest composed of red alder, black cottonwood, and Pacific willow trees. Crown cover exceeded 50% in some areas where dense thickets of sapling red alder trees, Douglas spiraea, and salmonberry dominated. The northern portion of this area had been cleared and graded and .was dominated by herbaceous species. This grading has enhanced an existing swale that ran through the property. Avian species observed within this freshwater wetland habitat type included tree swallow, violet green shallow (Tachycineta tha//assina), barn shallow (Hirundo rustica), song sparrow, dark eyed junco, American crow, American robin, golden crown kinglet, house finch, Steller's jay, pine siskin, black-capped chickadee, rufous sided towhee, Northern flicker, pileated woodpecker, and hairy woodpecker. These avian species were noted to use the "edge" between the mixed wetland habitat type and the upland young conifer forest habitat type. Many of these avian species were feeding, nesting, and seeking cover either within the forested portions of this wetiand habitat type or within the adjacent upland forest plant community. This wetland plant community included a number of downed logs and a. slash pile. These habitat features were noted as heavily used as feeding areas, cover, and. perches. A number of small cavities were also noted to be used by swallows. Mammal species observed within this habitat type included deer mice, opossum, black tailed deer, and raccoon. Evendell -11 Welland/Wildlife Report -0006.! 05/10/2004 15:08 2535390514 SOLINDBUILT HOMES PAGE 22 Pacific tree frogs (Hy/a regilla) were also noted within this habitat type. As identified the apparent length of surface water ponding resulting from water retention by the wetland would be inadequate to provide spawning habitat for this species. MOVEMENT CORRIDORS As identified by onsite wildlife trials, small and medium size mammals appeared to be moving throughout the project site and into the adjacent areas. The larger of these trails (many of which are logging roadways and draglines) also appeared to be used by domestic cats, domestic dogs, horses, and neighbors. Wetland A also appeared to serve as a movement corridor for a wide variety of wildlife species. PRIORITY SPECIES Two wildlife species identified by the State of Washington as "Priority Species' were observed onsite during this assessment. Black tailed deer and ruffed grouse are noted by the State of Washington as a "priority species' because these species are regulated as "game" species. The project site may also provides suitable habitat for other game species such as mourning dove (Zenaida marroura) and band-tailed pigeon (Columba fasciata). STATE CANDIDATE SPECIES A single "State Candidate· species -the pileated woodpecker -was observed to utilize the forested wetland area along with the adjacent upland forested areas onsite. State candidate species are presently under review by the State of Washington Department of Fish and Wildlife (WDFW) for possible listing as endangered, threatened, or sensitive. WDFW has developed a list of recommendations for management of the pileated woodpecker that focused on the preservation of nesting habitat. As defined by WDFW the most popular nest trees are typically hard snags with bark and broken tops within riparian areas. , REGULATORY CONSIDERATION The proposed alteration of lands defined by various federal, state, and local authority rules and regulations as "wetlands" raises environmental concerns that are generally addressed in the development review process. These concerns center around the development's potential adverse impacts to the structure, function, value, and size of these "wetland" areas. Such adverse impacts may include a reduction in wildlife habitats, reduced surface water quality, reduced water retention, a reduced ground water recharge rate, reduced plant species diversity, and the reduction in the function and value of other associated wetland and non-wetland characteristics. Evendell-12 WetlandNVildlife Report • 00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 23 U.S. ARMY CORPS OF ENGINEERS -Section 404 Section 404 of the Clean Water Act (33 U.S.C. 1344) prohibits the discharge of dredged or fill material into ''Waters of the United States" without a permit from the Corps of Engineers (Corps). The Corps has jurisdiction over freshwater systems waterward from the ordinary high water line of a water body or waterward from the upland boundary of the adjacent wetland. The definition of fill materials includes the replacement of aquatic areas with dry land, grading which changes the surface contour of a wetland, and mechanized land clearing in wetlands. For the purposes of Section 404 permitting the Corps makes the final determination as to whether an area meets the wetland definition and would be subject to regulation under the Corps program. Currently the Corps has two specific types of permits which apply to wetland fill proposals. These two types are a series of specific Nationwide Permits and the Individual Permit. The Nationwide Permit process identifies specific categories of work that can be undertaken following a set of specific conditions applicable to each Nationwide Permit number. For example; NWP#12 allows for the limited, short term impacts to wetlands for the placement of utilities, and NWP#14 allows for a limited impact to wetlands as a part of the development of a roadway.crossing. The Corps has noted several times within information papers, documents, and workshops that a project proponent that places fill within a wetland without specific Corps authorization does so at the proponent's own risk. The Corps requires an Individual Permit where a proposed activities within an identified jurisdictional wetland area can not be.authorized under one of the Nationwide Permits. Within the Individual Permit process the Corps undertakes a much more in- depth review of the proposed project and the proposed impacts. The Corps must evaluate whether the benefits derived from the project outweigh the foreseeable environmental impacts of the project's completion. · KING COUNTY -"Environmentally Sensitive Areas" Ordinance 21A.24 • Wetland and Stream Classes King County regulates activities in and around wetland areas. Such regulations also require that an undisturbed native vegetation buffer be retained along the upland side of the identified wetland areas. To assist in this regulation the County has defined classes by which to regulate wetlands, streams, and their associated buffer area. These categories are based on such features as size; the presence of endangered or threatened plants, fish, or animals; regionally rare wetlands; wetlands of local significance for wildlife or stormwater functions; the number of wetland classes and subclasses; and percentage of open water. A Class 1 Wetland means a wetland assigned the Unique/Outstanding rating in the King County Wetlands Inventory, or any wetland which meets any of the following criteria: Evendell • 13 Wetland/Wildlife Report -00062 05/10/2004 15: 08 2535390514 SOUNDBUILT HOMES PAGE 24 '·-· 1. The presence of species listed by the federal government or state . as endangered, or threatened, or the presence of critical or outstanding actual habitat for those species; · . 2. Wetlands having 40% to 60% permanent open water in dispersed patches with two or more classes of vegetation; 3. Wetlands equal to or greater than ten acres in size and having three or more wetland classes, one of which is open water; or 4. The presence of plant associations of infrequent occurrence. A Class 2 Wetland means a wetland assigned the Significant #2 Rating in the King County Wetlands Inventory; or any wetlands which meet any of the following criteria: 1. Wetlands greater that one acre in size; 2. Wetlands equal to or less that one acre in size and having three or more wetland classes; 3. Wetlands equal to or less than one acre that have a forested wetland class; 4. The presence of heron rookeries or raptor nesting trees. A Class 3 Wetland means a wetland· assigned a Lesser Concern #3 Rating in the King County Wetlands Inventory, 1983, or uninventoried wetlands that area equal to or less than one acre in size and that have two or fewer wetland classes. A Class 3 Stream means those streams that are intermittent or ephemeral during years of normal rainfall and are not used by salmonids. • Wetland/Stream Alteration King County allows a limited amount of alterations to wetlands provided all impacts are mitigated pursuant to an approved mitigation plan. For example, on a site larger than 20 acres in size, up to three isolated wetlands may be altered by combining their functions into one or more replacement wetlands pursuant to an approved mitigation plan (21A.24.330.K). The County defines an "isolated wetland" as those Class 3 Wetlands whose total size is less than 2,500 square feet and which area hydrologically isolated from other wetlands or streams. o Roadway Improvements King County will allow a roadway to cross a wetland or associated buffer where the following are met (21A.24.330.N):. 1. King County determines that no alternative access is practical; 2. all crossings minimize impact to the wetland and provide mitigation for unavoidable impacts through restoration, enhancement, or replacement of disturbed areas; · Evendell • 14 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 25 3. crossings do not change the overall wetland hydrology; 4. crossings do no diminish the flood storage capacity of the wetland; and 5. all crossings are constructed during summer low water periods. a Required Buffers King County has established a standard buffer to be applied to a wetland or stream to assure protection of the wetland function and value. This buffer area is measured perpendicular to the defined wetland edge or perpendicular to the identified ordinary high water mark of a stream. WETLAND CLASS STANDARD BUFFER WIDTH 1 100 feet 2 50 feet 3 •. 25 feet King County aHows the standard buffer to be modified where such actions would provide additional protection to wetlands or enhance the wetland's functions (21A.24.320.B). Buffer averaging may be allowed as long as the total area contained in the buffer on the development proposal site does not decrease and the minimum width of the final buffer is not less than 65% of the standard buffer width. SELECTED ACTION PLAN The Selected Action Plan of the Evendell Residential Community focuses on the creation of independent lots suitable for the development of single-family homesites consistent with the King County Comprehensive Plan. An essential element of this process is the development of access roadways and utility corridors which both meet King County health and safety standards and meet the goal of avoidance and minimization of potential short-term or long-term adverse impacts to aquatic environments. A primary feature in the creation of these homesite lots will be the establishment of a protective buffer adjacent to the identified onsite wetland consistent with the King County Environmental Sensitive Areas Ordinance. The creation of these homesite lots will not require the adverse impact or placement of fill within identified wetland areas. To provide additional protection for the onsite wetland, the buffer in the northwest corner · will be increased by the addition of 15,495 square feet. Through averaging, the buffer on the west side of the wetland will be reduced to 32.5 feet, a total of 9,340 square feet. Through buffer averaging these unavoidable intrusions into the standard buffer areas will be fully compensated and will not adversely impact the adjacent wetland areas. The development of this residential community will require the creation of a public roadway access by extending the existing 1581h Avenue South roadway which presently Evandell -15 Wetland/Wildlife Report -00062 ' 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 25 ends at Southeast 136th. In addition, site development requires improvements to the existing right-of-way (SE 1361h Street -a. primary collector route for the area) which fronts the project along its northern boundary. This will require the unavoidable filling of the northern 200 square feet of Wetland A and the reduction of the buffer associated . with this area of the wetland by 4,649 square feet. Through restoration of the existing onsite wetland, additional of buffer area along the eastern side of Wetland A, and onsite erosion protections these unavoidable intrusions into the wetland and standard buffer areas will be fully compensated and will not adversely impact the remaining wetland area. ELEMENTS OF THE COMPENSATORY MITIGATION PLAN Site planning for the Evendell Residential Community project site has focused on the mandated hierarchy of wetland impact reduction: 1) avoidance, 2) minimization, and 3) compensation. These avoidance and ,minimization strategies included a site design to reduce impacts to onsite wetland systems. The total amount of wetland area to be unavoidably modified by this project equals 200 square feet. As compensation for this unavoidable impact to Wetland A resulting from the development of SE 136th Street approximately 4,000 square feet of existing degraded wetland area will be enhanced through the planting of native trees and shrubs. The presently degraded buffer adjacent to the restored wetland area will also be restored and enhanced. Through buffer averaging the final protective buffer will be established to ensure that there is no reduction in the total area of buffer onsite and that the final buffer enhances the on site wildlife habitats and greater long-term protection of the wetland. PROJECT ELEMENT IDENTIFIED IMPACT Reduction of the standard 50 9,340 sqft of buffer foot buffer along the western eliminated edge of Wetland A to 32.5 feet. Elimination of 4,649 square 4,649 sqfl of buffer feet of buffer along the eliminated northern edge of Wetland A to develop SE 136th Street. Elimination of 200 square feet 200 sqft of wetland of buffer along the northern eliminated edi::ie of Wetland A to develop COMPENSATION PROVIDED 10,000 square feet of buffer will be added to the eastern side of Wetland A. This addition of buffer will provide greater protection to the wetland through the addition of mature trees and a very dense vegetation communit~ 5,495 square feet of buffer will be added to the eastern side of Wetland A. This addition of buffer will provide greater protection to the wetland through the addition of mature trees and a very dense vegetation communitv The existing degraded part of Wetland A onsite will be enhancement with the olantina of native trees and shrubs. Evendelt-16 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 27 1 SE 136tn Street. DESCRIPTION OF THE COMPENSATORY MITIGATION PROGRAM 1. As compensation for the unavoidable impact to 200 square feet of onsite King County Class 2 Wetland a presently degraded area of wetland adjacent the existing homesite equal to 4,000 square feet will be restored. Wetland restoration will be accomplished through the planting of native trees and shrubs. In addition, site design will ensure that there will be no adverse changes in the existing wetland hydrology patterns (Attachment 1). 2. The buffer associated with the identified onsite wetland will be established and identified onsite. The width of the protective buffer area shall be averaged so the total square footage surrounding the buffer does not decrease and that additional protection to the wetland is provided. Along the western buffer boundary the buffer width will be reduced to 65% of the standard buffer width for a Class 2 Wetland, to 32.5 feet as measured perpendicular for the identified wetland boundary. For the eastern buffer boundary, the buffer width will be increased to a maximum of 100 feet, and will encompass the entire corner to the project site. Once identified the wetlands and associated buffers will not be adversely modified by future land use actions. 3. As a part of the development of the required roadway improvements the actual encroachment into buffer area of Wetland A will be held to the minimum necessary to meet County roadway requirements along the SE 1361h Street Corridor. Following placement of the roadway improvements the roadway side slope within the buffer areas will be seeded with the defined grass seed mixture (Attachment 1). 4. As compensation for the unavoidable encroachment into the buffer associated with Wetland A as a part of the development of SE136th Street the standard buffer along the east side of this wetland will be increased. This buffer width increase is designed enhance the . wetland's function through improved visual and auditory blockage from the street crossing and greater wildlife habitat opportunities. 5. As a part of the development of the required roadway improvements the actual . encroachment into buffer area of Wetland A will be held to the minimum necessary to meet County roadway requirements along the SE 1361h Street Corridor. Following placement of the roadway improvements the roadway side slope within the buffer areas will be seeded with the defined grass seed mixture (Attachment 1 ). 6. All onsite activities will be monitored by the onsite biologist. The onsite biologist shall identify planting locations and planting patterns within the restored wetland and buffer. Following the completion of onsite planting activities a "record-drawing" plan will be prepared and submitted to King County .. A five-year monitoring program will be undertaken to assure the success of the compensatory mitigation plan. A project Evendell-17 Wetland/Wildlife Report • 00062 ' 05/10/2004 15:08 2535390514 SOLINDBUILT HOMES PAGE 28 financial guarantees will also be implemented to assure that the proposed work is completed and is successful. 7. Temporary and long-term erosion control measures will be implemented. These measures include silt fencing during site preparation and wetland construction, and seeding of exposed soil areas. 8. The outer boundary of the wetland buffer will be marked and fenced to limit intrusion into these areas. GOAL AND OBJECTIVE OF THE MITIGATION PLAN The GOAL of the Compensatory Mitigation Plan is to fully compensate for the unavoidable adverse impact to 200 square feet of wetland area and to enact a buffer averaging program that provides greater protection to the onsite wetland. This wetland area meets the criteria for designation as a King County Class 2 Wetland and presently exhibits a low function and value rating. ·. The proposed restored wetland area will be within with the northern portion of Wetland A will provide full compensation for unavoidable project impacts while also enhancing the function and value of the wetland. Upon the completion of this mitigation plan there will be no net loss of King County regulated wetland functions or values, an increase in the potential for the buffer to protect aquatic habitats, and an increase in the potential to provide long- term protection of wetland and buffer areas through an enhancement of a degraded wetland. ' To achieve the defined GOAL, the following OBJECTIVES are defined: • Plant Community Structure A. The enhanced compensatory mitigation wetland area will total 4,000 square feet and will exhibit a scrubfshrub and sapling tree vegetation classes within five years following initial planting (palustrine, scrub/shrub, seasonally flooded -PSSC). • Natural Biological Attributes 8. The compensatory mitigation wetland and the associated buffer will include the placement of snags and downed logs which provide nesting and cover habitat for passerine birds common to the area within five years. PERFORMANCE CRITERIA Evendell-18 WeUand/Wildlife Report. 00062 05/10/2004 15:08 25353'30514 SOUNDBUILT HOMES PAGE 2'3 To establish whether the defined project OBJECTIVES have been met by the_wetland mitigation plan, the following PERFORMANCE CRITERIA have been established to apply to the compensatory mitigation wetland area. Objective A. The compensatory mitigation wetland area will total 4,000 square feet in size and will exhibit scrub/shrub and sapling vegetation classes within five years following initial planting (palustrine, scrub/shrub, seasonally flooded -PSSC). Performance Criteria: As defined by Canopy Coverage Method sampling (0.25 m2 plot frame) the emergent plant community within the 4,000 square feet of the compensatory mitigation wetland area will exhibit at least an 80% coverage within five years following initial planting. As defined by Line- intercept Method sampling the scrub/shrub and sapling vegetation class will exhibit at least a 50% aerial coverage within five years following initial planting in those areas not identified as open water. Performance Criteria: At the end of the first growing season 100% of the installed trees and shrubs will be alive and exhibit growth. Those species identified as dead will be replaced prior to the start of the second growing season. Performance Criteria: At the end of the fifth growing season 80% of the trees and shrubs (species combined) will be alive and exhibit growth. Objective B. The compensatory mitigation wetland and the associated buffer will include the placement of snags and downed logs which provide nesting and cover habitat for passerine birds common to the area within five years. Performance Criteria: A minimum of three (3) stumps (minimum 10 feet in length, minimum 20 inch diameter at the top, minimum 10 foot diameter at bottom of rootball) and a minimum of three (3) downed logs (minimum 20 feet in length, minimum 20 inch diameter at 10 feet above root collar, minimum 10 foot diameter at bottom of rootball) will be placed within the compensatory mitigation area to provide habitat for passerine birds common to the area. (Appendix B). Performance Criteria: The compensatory mitigation area will be used for cover by at least two species of passerine birds common to the area within five years of completion of construction of the mitigation area. This will be monitored through observations and photographs of individual birds and habitat utilization. MITIGATION REPLACEMENT/ENHANCEMENT Evendell • 19 WetlandM/ildlife Report • 00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 30 The selected mitigation area will make an improvement to the functions and values offered by the existing onsite wetland and buffer while also providing a wider range of functions and values not presently exhibited onsite. Primary features offered by the selected mitigation plan includes a higher functioning wetland area, greater water quality protection to downstream resources, greater opportunity for biofiltration of surface water, greater water storage capacity, greater diversity of plant species and plant community associations, greater diversity of wildlife habitats. Overall, the proposed mitigation plan will provide a higher quality and a wider range of functions and values per unit area that presently exiting onsite within Wetland A. The proposed mitigation plan offers the opportunity to replace existing low function wetland with an area of greater functions and values. In addition, provisions will be put into place that will allow for the long-term protection and preservation of the entire wetland mitigation area, together with monitoring to ensure that the plant communities and wetland hydrology features are established. SUMMARY TABLE OF WETLAND FUNCTIONAL BENEFITS MITIGATION ELEMENT WETLAND FUNCTION BENEFITS Establishment of a diverse plant community • Natural Biological Function and habitat features within the wetland and • Water Quality buffer areas. Enhancement of the mitigation wetland area • Hydrologic Support through selective site e)(cavation. • Stormwater & Floodwater Storage • Water Quality • Natural Biological Function • Groundwater Recharae Removal and management of invasive • Water Quality species. • Natural Bioloaical Function Use of temporary and long-term erosion • Water Quality control technolonv. SELECTED PLANT COMMUNITIES The plant communities and plants selected for the created wetland and restored/ enhanced wetland and buffer areas will be obtained as nursery stock. These selected species are native and commonly occur in the local area. The plant species are selected to increase plant diversity, match present onsite communities, increase wildlife habitats; and enhance the aquatic environment. NUMBER COMMON NAME LOCATION SCIENTIFIC NAME 20 Western red cedar (THP) Wetland and Thuia ollcata buffer PROPOSED PROPOSED INDICATOR SPACING (oc} SIZE STATUS 12-15ft 5 fl height FAG minimum Evendell-20 Wetland/WIidiife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES· PAGE 32 essential element during pre-construction site inspections and discussions. Onsite technical inspection during construction and planting activities will be implemented by the combined efforts of the project biologist and King County wetland staff. The project biologist will perform construction oversight and address minor unforeseen construction difficulties to assure that the intent of the buffer establishment plan is met. The project biologist shall also be responsible for assuring that the species and sizes of native plants selected and noted within the final planting plan are utilized during construction. The project biologist shall also be responsible for the placement of all trees and shrubs. If selected native species become unavailable, the project biologist will consult with King County wetland staff for substitute plant species to assure that the intent of the stream buffer establishment plan is met. Post-construction site inspection/ evaluation will include the preparation of a "record-drawings" which will be submitted to King County wetland staff. WATER QUALITY PROTECTIONS DURING CONSTRUCTION The project team will implement a wide range of water quality protective measures during and immediately following the construction of the compensatory mitigation area. This protective measures include the placement of appropriate silt fencing along the outer boundary of the buffer area to be established, short-term silt fencing adjacent to the specifically identified wetland and buffer excavation areas, work during the drier season of the year, the use of well maintained machinery, the seeding/mulching of all exposed soil surfaces within two weeks from the final completion of site excavation, and the irrigation of the wetland and buffer areas to ensure plant community establishment. In addition, best management practices as identified within the erosion control plan prepared for this project site will be used during the entire construction phase to protect water quality. CONSTRUCTION SEQUENCE TASK APPROXIMATE DATE OF COMPLETION Initial onsite team meeting to define final construction steps September 30, 2001 and oroiect team tasks. Onsite marking of wetland creation area and outer buffer October 15, 2001 boundaries. Placement of protective silt fencing and other erosion protections as needed . . Planting of wetland and buffer areas. Final construction report PROJECT MONITORING November 15, 2001 November 30, 2001 Evendell-22 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 33 Following the successful completion of the proposed compensatory mitigation plan a five-year monitoring and evaluation program will be undertaken. The purpose of this program is to assure the success of the selected mitigation as measured by an established set of performance criteria (see above). This monitoring will also provide valuable information on the effectiveness of mitigation procedures. STANDARDS OF SUCCESS Vegetation Sampling Methodology and Monitoring Schedule Permanent vegetation sampling plots will be located within each planting community in areas representative of the communities being sampled. These sampling plots will be located along specific transects and at stationary identified points. Observations and measurements will be recorded for all plant species in order of dominance based on the relative percent cover for each species within the various vegetation strata. Sampling for tree and shrub species will be completed in 30-foot radius sampling plots. Stratified methods will be used .to increase the precision of sampling data while also maintaining elements necessary for statistical inferences. The evaluation of the success of the enhancement program will be based on the expected cover percentages to be defined within the final compensatory mitigation plan and the selected 80% survival rate at the end of the fifth growing season following initial planting. The percent of aerial cover and the percent survival rate will be based on combined counts of existing and planted species during vegetation monitoring. Sample location will be shown on the design and the "record drawings" plans, and will correspond to identified photo points. Trees and shrubs will be visually evaluated to determine the rate of survivorship, health, and vigor of each plant. The categories to be used will include live, stressed, tip dieback, basal sprouts. not found, apparently dead, and dead. Vegetation Monitoring 1. Upon the completion. of initial planting and as a part of each monitoring period the project biologist will count the number of plants which were planted within the wetland and buffer areas. 'Plants will be identified to species and observations of general plant condition (Le., plant health, amount of new growth) are to be recorded for each plant. 2. At identified sample plots within the created wetland and the enhanced buffer areas the project biologist will. determine percent coverage of vegetation using the Canopy Coverage Method sampling (0.25 m2 plot frame) procedure for emergent species and by using the Line-intercept Method sampling procedure for the scrub/shrub and sapling tree species. 3. Within the entire mitigation area the project biologist will count the number of undesirable invasive plants and estimate the aerial coverage (as if the observer Evendell -23 Wetland/\Nildlife Report. 00062 • 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 34 were looking straight down from above) of these invasive plants. Undesirable plants include blackberries, Scot's broom, tansy ragwort, reed canarygrass, and other such plants listed in the Washington State Noxious Weed List 4. Within the entire mitigation area the project biologist will count the number of desirable "volunteer'' plants and estimate the aerial coverage of these plants. 5. The project biologist will take photographs that show the entire mitigation area. During the five-year monitoring period photos will be taken in the same direction and at the same location to provide a series of photos. These photos will show plant growth, plant species, and plant coverage. 6. Upon the completion of the initial project planting and upon the completion of each monitoring period the project biologist will prepare a report defining methods, observations, and results along with the date the observations were completed. Each report will be sent to King County wetlands staff. 7. The monitoring schedule is defined as: A. At the completion of initial project planting. This report will include a "record drawing" defining the species used, locations, and general site conditions. This report will also include a "lessons learned" section to assist in future monitoring and final project assessment. This "record drawing• and report will be provided to the County within two weeks after the completion of onsite planting. B. Twice a year for years one through three following the completion of initial · onsite planting. For each monitoring year, onsite monitoring will be completed once early in the growing season (late March to mid-Apdl} and once again near the end of the growing season (mid-September}. For each onsite monitoring activity a report will be prepared and provided to the County within two weeks after the completion of onsite monitoring. C. Once a year for years four and five following the completion of initial onsite planting. For each monitoring year, onsite monitoring will be completed once near the end of the growing season (mid-September}. A report will be prepared and provided to the County within two weeks after the completion of onsite monitoring. MONITORING YEAR YEAR~1 YEAR-2 YEAR-3 Vegetation Monitoring Sequencing . VEGETATION MONITORING On or about April 15, 2002 on or about Sept. 15. 2002 On or about Aoril 15, 2003 on or about Sept. 15, 2003 On or about Aoril 15 2004 SUBMITTAL OF MONITORING REPORT Report due Mav 25, 2002 Reoort due Oct. 15 2002 Report due Mav 25, 2003 Report due Oct. 15, 2003 RePort due May 15 2004 Evendell -24 Wetland/Wildlife Report • 00082 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 35 on or about Seo!. 15, 2004 Report due Oct. 15. 2004 YEAR-4 on or about Seo!. 15, 2005 Report due Oct. 15, 2005 YEAR-5 on or about Seot. 15. 2006 Reoort due Oct. 15, 2006 The last monitoring report dated October 15, 2006 will include notification to the County biologist that the monitoring program has concluded and that County review and site inspection is required for project analysis and release of the financial guarantee. This final report will also include a "lessons learned" section to assist and final project assessment and to potentially assist in the evaluation other mitigation projects. WILDLIFE OBSERVATIONS Observations of wildlife will coincide with the onsite activities undertaken as part of the Vegetation Monitoring Program. The onsite team will document the extent of bird species abundance, site utilization, nesting and feeding activities, and species diversity. In addition, documentation of terrestrial and aquatic reptiles, amphibians, and mammals observable without trapping will also be documented. Wildlife observations will be documented within the Vegetation Monitoring Reports noted above. VEGETATION MAINTENANCE PLAN Maintenance of the enhanced wetland and buffer plant communities may be required to assure the long-term health and welfare of the wetland's and buffer's environmental functions. Such maintenance would be identified during the monitoring period and undertaken only following discussion and coordination with King County wetland staff. The overall objective is to establish undisturbed plant communities that do not require maintenance. · Activities may include, but are not limited to, the removal of invasive non-native vegetation and the irrigation of selected areas. Established maintenance activities include the removal of any trash within the wetland and buffer. Temporary irrigation will be established (if necessary) to ensure one-inch of water from June through September of the first year following installation of the plantings. The need for temporary irrigation of these areas during subsequent years will be defined during the spring monitoring period. REMOVAL OF INVASIVE NON-NATIVE VEGETATION As a contingency, should the removal. of invasive non-native vegetation become necessary, the project proponent will contact King County wetland staff to establish and define specific actions to be taken. Resultant contingency plan activities will be implemented when the ongoing vegetation monitoring program indicates that plants listed in the Washington State Noxious Weed List, blackberries, Scot's broom, tansy ragwort, or reed canarygrass are becoming dominant in the community. Evendell -25 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 35 CONTINGENCY PLAN As a contingency, sh.ould the proposed compensatory plan fail to meet the performance criteria, the project proponent will undertake required remedial actions. Where plant survival is the failing component, the project proponent will replant and assure the success of this second planting which would be held to the same standard of success as measured by threshold criteria and monitoring processes. Should additional remedial actions be required, the project proponent will meet with King County wetland staff to establish and define actions to be taken to meet the desired goal of this program. PLANTING NOTES All plant materials shall be native to the Puget Sound Region. The onsite biologist shall inspect plant materials to assure the appropriate plant schedule and plant characteristics are met. The project proponent shall warrant that all plants will remain alive and healthy for a period of one-year following completion of planting activities. The project proponent shall replace all dead and unhealthy plants with plants of the same specifications. FINANCIAL GUARANTEE Financial guarantee will be provided for this project to ensure project completion and performance. This guarantee is defined using the standard King County Bond Quantity Worksheet (Appendix B). Evendell -26 Wetland/Wildlife Repor1 -00062 05/10/2004 15:08 ) 2535390514 ' l32ND ST l Q '""' r ::e ~~RD ST iJ 14~1 136TH :§45o--r--- SE 138TH PL {/ ~ §c ~ osa 139TH PL ~I~ o I I,_, §; I SE 141ST f ST . 8 "" SE 142ND f:'.::; SOUNDBUILT HOMES ~IT ' ,...,,SE I LIBER'(Y ~ HS I LtJ ' U'J' 1 I :;: ST ; "' ~ SE /i4,?f0 ,;i ;i ST ,-,_ PL i: SE 1'cr (i ~/-=-'~:C....'E;:.....;::.;lc...44TH ~! t 1:t 0li ; i 15900 i=: .,.,1 MID :i ... ' I IHIABB'f A 'ii li"'ECIH!NOIL~GRES fi~Mrre "ii Site V§cili'ility PAGE 38 05/10/2004 15:08 2535390514 ii-'\ :~ .• '<4 •.• · •• '! . . ·. \ ; ' ·. -l... \ ...... '-... ,j 't·· '•. -·· ........ _ . ,, ·~'"' .. ._..· .. IHI.AD BY A "if' Y!EeHNO!b@GUE~ <•;'• SOUNDBUILT HOMES PAGE 39 ~,.) \t .··~ . -~ ,.:• ,.· . .., ..... ~ . • _. __ _...._....J,... ---,-......... ' ~ \. ;, • ·;, \ Figure 2 NWD Resource Mapping fo 05/10/2004 15:08 ' '· 2535390514 I I I I I I I I I I f ---· IHIA~DTAT TECHNOLOGIES i I I I SOUNDBUILT HOMES PAGE 40 Figure 3 PHIS Resource Mapp&ng 05/10/2004 15: 08 2535390514 a.II' a . • • • .. •· • • . .. OR D-Q., o•· • • • .. AgC SOUNDBUILT HOMES . . • ---- 0 D°' a,~ .. ·o •• • • .. ~ .. ----- ( a • i+a· a-· a a • • a • • • • • • •• •· • &· .. • .. •• • • • • • • • ··o:· ]:•;,a -:.[__: .· ' a'D ~ D· . , .. Ila,· . .. · • • • • a . • • • • • Figure 4 D Soil Mapping PAGE 41 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 42 REFERENCE LIST Adamus, P.R., E.J. Clairain Jr., RD. Smith, and RE. Young. 1987. Wetland Evaluation Technique (WET); Volume II: Methodology, Operational Draft Technical Report Y-87, U.S. Army Engineer Waterways Experiment Station, Vicksburg. Mississippi. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. Office of Biological Services, U.S. Fish and Wildlife Service, U.S. Department of the Interior, FWS/OBS-79/31. Environmental Laboratory. 1987. "Corps of Engineers Wetlands Delineation Manual," Technical Report Y-87-1, US army Engineer Waterways Experiment Station, Vicksburg, Miss. Hitchcock. C.L, A. Cronquist. 1977. Flora of the Pacific Northwest. University of Washington Press. Seattle, Washington. · Horner, R.R. and K.J. Raedeke. 1989. Guide for Wetland Mitigation Project Monitoring. Washington State Department of Transportation. contract number GC8286, task 6. King County Department of Natural Resources. 1993. DRAFT Wildlife Management in King County: Issue Paper. Mikol, S.A. 1980. Field Guidelines for Using Transects to Sample Nongame Bird Populations. U.S. Fish and Wildlife Service publication FWS/OBS -80/58. Reppert. RT .. W. Sigleo, E. Stakhiv, L. Messman, and C. Meyers. 1979. Wetland Values -Concepts and Methods for Wetiand Evaluation. Research Report 79-R1, U.S. Army Corps of Engineers, Institute for Water Resources. Fort Belvoir, Virginia. U.S. Department of Agriculture, Soils Conservation Service. Soils Survey of King County Area Washington, Nov. 1973. Washington State Department of Ecology. 1997. Washington State Wetlands Identification and Delineation Manual. Publication Number 96-94. Washington State Department of Fisheries, Catalog of Washington Streams and Salmon Utilization, Volume 1., 1975 Evendell -28 Welland/WIidlife Report -00062 • 05/10/2004 15:08 2535390514 .•. ,_.. SOUNDBUILT HOMES APPENDIX A FIELD DATA FORMS Evendell-29 Wetland/Wilallfe Report -00062 PAGE 43 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 44 SAMPLEPLOT_S~P~1'--~~~~~- DATAFORM ROUTINE WETLAND DETERMINATION (1987 COE WETLANDS DEUNEATIOI\I MANUAL) Projec:t/Sile Applicant/Owner. Investigator: ... eve-"nd=el;..I __ ..;... ______________ Date: 17 July 2000 ~M::.:r.,.:.M;.;;i .. ke~R"'om __ an;;.;0::...,...--------------County: _P:.,i:;:;e.:.:rc:.::ec..._ ___ _ ..:.,:H:;ab::i:::la::.l .:.Te::;:ch::.::;n.:::ol=i::::es::... ________ _,, .... ----State: washington Have vegetation, soils, or hydrology been cfJSturbed? Is the area a potential Problem area? (If needed, explain on reverse) YES YES Community ID: Transect 10: Plot ID: SP1 VEGETATION (Note those species obsen,ed to have morphological adaptations to wetlands with an*) no nfn~n, Plant "Mcie" St""'u-ln"•~~•or I Do-inant P'ft"' Sne~•fts Stratum 1. 2. Acer macronhvllum Tree FACU 3. S:1n, Corvlus comuta Shrub FACU 4. Rubus snectabllls Shrub FAC+ 5. Rubus nrocera Shrub FACU 6. Rubus lacinatus Shrub FACU- 7. Pteridlum aauilium Herb FACU 8. 1 <>en:ent of Dominant species that are OBL, FACW, or 0% \C (except FAC.). lndude species noted (') as showing or .11orphological adaptations to wetlands --------------------------l I Describe Morphological Adaptations: Remarks: Near nraded roadbed liYDROLOGY Recorded Data (Descrtbe in Remarks): -Stream, Lake, or Tide Gage __ Aerial Photograph __ Other ~ No Recorded Data Available FIELD OBSERVATIONS: Depth of Surface Water: o• Depth to Free Water Pit: O • · · Depth to Saturated Sotl: ...;D;;.'_ Remarks: Deciduous forest Wetland Hydrology Indicators: -Inundated Saturated in upper 12" Water Marks Drift Lines Sediment Deposits Drainage Patterns in Wetlands ...!_ Oxidized Root Channels In Upper 12" Water-stained Leaves -Local Soil Survey Data -other (,Explain In Remarlls) • 05/10/2004 15:08 2535390514 lap Unit Name: AlderwoOd gravelly sandy raxonomy (Subgroup):Oystric Entlc Durochrepts Profile Description: Depth (Inches) Horizon Matrix Color (Munsell Moist) 0-18 10 YR 313 Hydric Son Indicators: Hlstosol --Histic Eplpedon Sulfidlc Odor ------Probllble Aquic Moisture Regime ---Reducing Conditions ---Gleyed or Low Chroma Colors ~emarks: . ,eld indicators of hydric soil NOT present WETLAND DETERMINATION Hydrophytf<: Vegetation Present? Hydrlc sons Present? Wetland Hydrology Present? Remarks: WETLAND CRITERIA NOT MET YES' YES YES SOUNDBUILT HOMES PAGE 45 SAMPLE PLOT $Pf ~--------Drainage Class: · Field Obsenrations Confirm Mapped Type Yes No Mottle Colors (Munsell Moist) MotUe Texture, Concretions None Abundance/Contrast Rh~pheres, etc. None Gra\relly loam Concretions ------High Organic Content in Surface Layer ---Organic Streaking ---Listed on Local Hydric Soils List ___ Listed on National Hydric Soils List ___ Other (Explain in Remaoo) Is this Sampling Point within a ~ Wetland? ~ Area appears to drain well following seasonal stonn events •• 05/10/2004 15:BB 2535390514 SOUNDBUILT HOMES PAGE 45 SAMPLE PLOT SP 2 --------- DAT A FORM ROUTINE WE11AND DETERMINATION (1987 COE WETLANDS DELINEATION MANUAL) Project/Site Applicant/Owner. Investigator. ___ Ev_e.,,.n_de_1..,1 -------------------Datil: 17 July 2000 Mr. Mike Romano Coumy: Pierce ----,,,_.,.....,....,..______________ -------- ....;,:H;;;a bi;;;" l;;;at;;..;.T e""ch=n~o l;.;;oga;i;.;;e s""--------------State: Washington Have vegetation, soils, or hydrology been disturbed? Is the area a potential Problem area? (If needed. explain on reverse) YES {Nd) YES '(!!J Community ID: Transect ID: Plot 10: SP2 VEGETATION (Note those species observed to have morphological adaptations to wetlands with an •1 On ,1nant Ptant !':nei-Jes s•-,..., lnrU,.-<itor I Oom;nant Plant S""cles Stratum Indicator 1. 2. Sao. Poculus trictrocaroa Shrub FAC 3. Carex obnu111a Hert, OBL 4. Juncus effusus Hert, FACW 5. 6. 7. 8. 1 Peroent of Dominant spacies that are OBL, FACW, or 100% \C (except FAC-). Include species noted (") as showing .,orphological adaptations to wetlands ---------------------------! I Describe Morphological Adaptations: Remarks: . swale depression on edae or homesite area HYDROLOGY Recorded Data (Describe in Remarks): -·Stream, Lake, orTide Gage __ . Aeriel Photograph Other X ""'N"""o-R-ecorded Data Available FIELD OBSERVATIONS: Depth of Surface Weter: o· Depth to Free Water Pit: o • Depth to Saturated Soll: D" -- Remarks: Depnissionlonal swale on edge of cleared homesita Next to slash pile and root ball ~and Hydrology Indicators: Inundated = Saturated lri upper 12" X Water Marks -Y-Drift Lines -Sediment Deposits -Y-Drainage Patterns in Wetlands -Oxidized Root Channels in UPJ)er 12 • l(°" Water-stained Leaves -Local Soll Survey Data -Other (Explain in Remari<S) 05/10/2004 15:08 2535390514 ap Unit Name: Alderwood gravelly sandy raxonomy (Subgroup):Dystrtc Entic Ourochrepts Profile Description: Depth (inches) Horizon Matrix Color (Munsell Moist) 0-6 10 YR2/1 6-18 10 YR 4/1 Hydrlc Soil Indicators: Histosot ---Histic Eplpedon ---Sulfldlc Odor _X'---Probable Aquic Moisture Regime --=--Reducing Conditions _x __ Gleyed or Low Chroma Colors "'emarks: rield indicators of hydric soil present WETLAND DETERMINATION Hydrophytic Vegetation Present? Hydric Soils Present? Wetland Hydrology Present? Remarks: WETLAND CRITERIA llllET NO NO NO SOUNDBUILT HOMES PAGE 47 SAMPLE PLOT SP 2 ,,,.;.'----------D ra In age Class: Field Observations confinn Mapped Type Yes No Mottle Colors (Munsell Moist) Mottle Texture, Concretions Abundance/Contrast Rhizospheres, etc. None None Gravelty loam 10YR3/2 PromJcommon Clay loam J{ Concretions ------High Organic Content in Surface Layer Organic Streaking ---Listed on Local Hydric Soils Lisi Listed on National Hydrie Soils List ------Other (Explain in Remarks) Is this Sampling Point within a ~ Wetland? · ~ Area appears to drain poorly following seasonal stonn events • 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 48 ··-·· SAMPLE PLOT SP 3 ---------- DATA FORM ROUTINE WEn.AND DETERMINATION (1987 COE WETLAll!DS DELINEATION MANUAL) Project/Site Applicant/Owner: Evendell Date: -:-:,.....,..,.,,--=------------------17 July 2000 Pierce Investigator. ~M-;r ·:--:M'."'i ... k e.,,...R~o m..._a "'no-,----------------County: ..... H ... ab .. it.;;;a;.;.t_.T.c..ech .... n .. ol .. og.,.l;.;;e.c..s ______________ State: Washington Have vegetation, soils, or hydrology been disturbed? Is the area a potential Problem area? (If needed, explain on reverse} YES 'No YES NO Community ID: Transect ID: Plot ID: SP3 VEGETATION (Note those species observed to have morphological adaptations to wetlands with an") Oomin"'nt Plant S""'"l"S Stratu"' I r I Don,;nant Pia"' ~-cles Stmum '""l""'Or 1. 2. Sao. Alnus rubra Shrub FAC 3. Carex obnuma Herb OBL 4. Phalarls arundinacea Herb FACW 5. Salix sitchensls Scrub FACW 6. 7. 8. J Percent of Dominant species that are OBL, FACW, or 100% C (except FAC-). Include species noted (j as showing Jrphological adaptations to wetlands --------------------------. I Describe Morphological Adaptations: Remarks: swafe domresslon on edge Of homesite al'l!11 HYDROLOGY _ Recorded Data {Describe in Remarks): --Stream, Lake, orT!de Gage Aerial Photograph --Other X No Recorded Data Available FIELD OBSERVATIONS: Depth of Surface Water. o· Depth to Free Water Pit O • _ Depth lo Saturated Soil: _O" ___ _ Remams: Depressionional swale on edge Of cleared llomeslte ~and Hydrology Indicators: Inundated Saturated in upper 12" -Y-Water Marxs -Y-Drift Unes -Sediment Deposits --;r-Drainage Patterns In Wetlands -Oxidized Root Channels in Upper 12 • x Water.stained Leaves Local Soll Survey Data -Other (E,cplain in Ramelb). 05/10/2004 15:08 2535390514 lap Unit Name: Afderwood gravelly sandy Taxonomy (Subgroup):Oystric Entic Durochrepts Profile Description: Depth (Inches) Horizon D-6 6-18 Hydric Soil Indicators: ---Histosof Histlc Epipedon ___ Sulfidlc Odor Matrix Color (Munseff Moist) 10YR2/2 10 YR 3/4 ___ Probable Aquic Moisture Regime Reducing Conditions ---Gleyed or Low Chroma Colors "!emarl!s: field Indicators or hydric soil not pl'l!Senl WETLAND DETERMINATION Hydrophytlc Vegetation Present? ~~ Hydrlc Soils Present? ~ .r. Wetland Hydrology Present? YES Remarks: WEn.AND CRITERIA NOT MET Sample plot on edge of defined wetland SOUNDBUILT HOMES PAGE 49 SAMPLE PLOT SP 3 ~--------Drainage Class: Field Obseivations Confirm Mapped Type Yes No Mottle Colors (Munsell MoisQ Mottle Texture, Concretions None None Abundance/Contrast Rhlzospheres, etc. None Gravelly loam none gravelly foam Concretions ------High Organic Content In Surface Layer Organic Streaking ---Listed on Local Hydric Soils List Listed on National Hydric Solis List ------other (Explain In Remalils) Is this Sampling Point within a ~ Wetland? Area appears to drain well following seasonal stonn events • 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 50 SAMPLE PLOT SP 4 _________ .;,__ Projeel/Site Applicant/Owner: Investigator: DATA FORM ROUTINE WETLAND DETERMINATION (1987 COE WETLANDS DELINEATION MANUAL) Evendell Date: ~~,..;,;..;-=-----------------_M,_,;;.;r. ~Mi::""-k e=-R-:'o m=a n .... o..,... ______________ County: ...... H.a_bi.tat:;...;;.T..;;.ech-=n;.;;o.;..;log""""ies..;;._ ______________ state: Have vegetation, soils, or hydrology been disturbed? Is the area a potentlal Problem area? YES NO YES NO Community ID: Transect ID: (If needed, explain on reverse) Plot ID: 17 July2DOO Pierce WaSllington SP4 VEGETATION (Note those species observed to have morphological adaptations to wetlands with an •1 On nlnant PJant 5.,.,r;es ~""'um lndlr<>+nr I Do-•--... Plant ,::.,ecies "'""um lnrlicator 1. 2. Sao. Alnus rubra Shrub FAC 3. Carex obnuota Herb OBL 4. Phalaris arundinacea Herb FACW 5. 6. 7. 8. J Percent of Dominant species that are OBL, FACW, or 100% .c (except FAC-). Include species noted (") as showing .orphologlcal adaptations to wetlands --------------------------; I Oesclibe Morphological Adaptations: Remarlls: swale depression on edae of homasite area HYDROLOGY Recorded Data (Deseribe in Remarks): __ Stream, lake, orTide Gage ___ Aerial Photograph Other X ...,N.,..o""'R,.-ecortled Data AvaHable FIELD OBSERVATIONS: Depth of Surface Water: o· Depth to Free Water Pit: 0 • Depth to Saturated Soil: o• --- Remarn: Depressionional swale on edge of creanid homesite Wetland HYl!rology lndlGStors: -Inundated Saturated in upper 12" -X-Water Mar1ts ,r--DriftUnes Sediment Deposits Y-Drainage Patterns in Wetlands -Oxidized Root Channels In Upper 12 • X--Water-Stained Leaves Local Soil Survey Data -Other (Explain In Remarlcs) • 05/10/2004 15:08 2535390514 ap Unij Name: Afderwood gravelly sandy , axonomy (Subgroup):Dystric Entlc Durochrepts Profile Description: Depth (inches) Horizon Matrix Color (Munsell Moist) 10 YR 211 6-18 10 YR 411 Hydric Soil Indicators: Histosol ------Histic Epipedon Sulfidic Odor -.---_;.:X:...__ Probable Aquic Moisture Regime ---Reducing Conditions ·X Gleyed or Low Chroma Colors Slemarlts: rield indicators of hydric soil present WETLAND DETERMINATION Hydrophytlc Vegetation Present? Hydric Soils Present? Wetland Hydrology Present? Remartcs: WETLAND CRITERIA MET NO NO NO SOUNDBUILT HOMES PAGE 51 SAMPLE PLOT SP 4 Drainage c"'r""ass--': :...__.;._ _____ _ Field Observations Comlrm Mapped Type Yes No Mottle COIOIS (Munsell Moist) Mottle T emu re. Concretions Abundance/Contrast Rhizospheres, etc. None None Graveffy loem 10YR 3/2 PromJcommon Clay loam X Concretions --''------High Organic Content In Surface Layer Organic streaking ---Listed on Local Hydric Soils Ust Listed on National Hydric Soils List ---Other (E,(plaln in Remarks) Is this Sampling Point within a ~ Wetland? lY Area appears to drain poorfy following seasonal storm events • 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 52 SAMPLE PLOT SPS Project/Site Applicant/Owner: Investigator: DAT AF O RNI ROUTINE WETLAND DETERMINATION (1987 COE WETLANDS DEUNEA TION MANUAL) Evendell Date: ...;;:;;;.;.;,;,.,...~----------------_M~r -~M:Cl':'k e:;"'R'.'::orn~a n:-'o~--------------County: _H:..:::;ab::::it:::at::.T.:..e::::c::.h:::n::::ol=l::::es:.__ _______ -,::,,~,-----State: Have vegetation, soils, or hydrology been disturbed? Is the area a potential Problem area? YES YES Community ID: Transect 10: (If needed, explain on reverse) Plot 10: --------- 17 July200D Pierce Washington SP6 VEGETATION (Note those species observed to have morphological adaptations to wetlands with an •J n" inant .,.,~,.. "'"ecles -· -· jn,ti~~•or I Domjnnnt Plant 5.,..,,;,._~ s lndi""'nr 1. 2. Alnus rubra Tree FAC 3. 4. 5_ Rubus r:,rocera Shrub FACU 6. Rubus laclnatus Shrub FACU- 7. Ptelidlum aaullfum Herb FACU 8. I Petcent of Dominant species that are 0Bl, FACW, or 25% C (except FAC-). Include species noted (") as showing . .:irphological adaptations to wetlands --------------------------; I Describe Morphological Adaptations: Remarlls: Cleared homesite area HYDROLOGY Recorded Dela (Describe In Remarks): -stream, Lake, or Tide Gage ___ Aerial Photograph Other ..L"""N.,..o-=R'""ecorded Data Available FIELD OBSERVATIONS: Depth of Surface Water. o· Depth to Free Water Pit: O • Depth to Saturated Soil: _o· __ --Rernartls: Deciduous forest WeUand Hydrology Indicators: Inundated Saturated in upper 12• ___ WaterMarks Drift Lines -Sediment Deposits -Drainage Pattems in Wetlands -Oxidized Root Channels In Upper 12 • ~ Water-stained Leaves -Local Soil Survey Data -other (Explaln in Remarks) 05/10/2004 15:08 2535390514 ap unn Name: Aklerwood gravelly sandy raxonomy (Subgmup):Oystric Entfc Dumchrepts Profile Description: Depth (inches) Horizon Matrix Color (Munsell Moist) 0-8 10YR 2/2 8-18 1DYR2/2 Hydric Soil Indicators: Histosol ------HistiC Eplpedon SuHldlc Odor ------Probable Aquic Moisture Regime Reducing Cond~ions Gleyed or Low Chroma Colors --- "emarll!I: rleld indicators of hydric soil NOT p1esent WEnAND DETERMINATION Hydrophytic Vegetation Present? Hydric Soils Present? Wetland Hydrology Present? Remarks: WETLAND CRITERIA NOT MET YES~ YES YES NO SOUNDBUILT HOMES PAGE 53 SAMPLE PLOT SP& ,,_ _______ _ Drainage Class: Field Observations Confirm Mapped Type Yes No Mottle Color.; (Munsell Moist) Mottle Texture, Concretions Abundanca/Contrast Rhlzospheres, etc. None None Gravelly loam 1DYR 5/8 FainVuncommon loam Concretions ------High Organic Content In Surface Layer Organic Streaking ---Listed on Local Hydric Soils List Listed on National Hydric Soils List ---Other (Explain in Remarks) --- Is this Sampling Point within a ~ Wetland? ~ Area appears to drain well following seasonal storm events .. 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 54 SAMPLE PLOT SP 8 ----------- DATA FORM ROUTINE WElLAND DETERMINATION (1987 COE WEn.ANDS DELINEATION MANUAL) Projed/Site Applicant/Owner. Investigator. _::Ev.:.:B~nd::B::;:1:..1 -----------------Date: 17 July 2000 ..:;.M~r-~M:::i:::.ke:.:.,:R:;:;om:.::::.a:.::no=----------------County: . -'P'-'i""erce=---- ..:..:H.::ab:::;11::a:.:.t .:...T:::ech=no::l:=i:::es:::... ______________ State: Washington Have vegetation, soils, or hydrology been disturbed? Is the area a potential Problem area? (If needed, explain on ll:!verse) YES YES Community ID: Transect ID: · Plot ID: SP 8 VEGETATION (Note those species observed to have morphological adaptations to wetlands With an") Domin·-• Plan• SMcies C>lrafu-lndf•-'Ao I Do • P'•-' "'-c;e .. s·---lnrllcator 1. 2. San. P""ulus Uiehocama Shrub FAC 3. 4. Juncus effusus Herb FACW 5. Rubus laciniatus Shrub FACU. 6. 7. 8. I Percent of Dominant species that are OBL, FACIN, or 66% C (except FAC-). Include species noted(") as showing .orphological adaptations to wetlands -------------------------1 I Describe Morphological Adaptations: Remarks: Sl"'ht deon,ssion on eciae Of homeslte area HYDROLOGY Recorued Data (Describe In Remarks): -Stream, Lake, or Tide Gaga __ Aerial Photograph __ Other . X No Recorded Data Available FIELD OBSERVATIONS: Depth of Surface Water. Cl" Depth to Free Water Pit O • Depth to Saturated Soil: o· , -Remams: Slight depression on edge of clea111d homesite Next to slash pile and root ball Watland Hydrology Indicators: -Inundated Saturated in upper 12" "'x Water Ma/ks Drift Unes Sediment OeposltS Drainage Patterns in Wetlands Oxidized Root Channels In Upper 12 • X Water-Stained Leaves = Local Soll Sur.,ey Data Other @!Plain in RemarltS) • 05/10/2004 15:08 2535390514 1ap Unit Name: Alderwood gravelly sandy . axonomy (Subgroup):Dystric Entic Durochrepts Profile Description: Depth (inches) Horizon MatriX Color (Munsell Moist) 10YR3/2 8-18 10YR4/3 Hydric Soil Indicators: Histosol -----HIS11c Epipedon Sulficlic Odor -----Probable Aqulc Moisture Regime ___ Reducing Conditions Gleyect or Low Chroma Colors --- Remarks: . ,eld indicators of hydric soil NOT present WE1\..AND DETERMINATION Hydrophytic Vegetation Present? Hydric Soils Present? Wetland Hydrology Present? G;)§3. YES . YES Remarks: WETLAND CRITERIA NOT MET SOUNDBUILT HOMES PAGE 55 SAMPLE PLOT SPB ,,,.----------0 rain age Class: Field Observations Confinn Mapped Type Yes No MotUe Colors (Munsell Moist) Mottle Texture, Concrations Abundance/Contrast Rhizospheres, etc. None None Gravelly loam None none loam Concretions ------High Organic Content in Surface Layer ___ Organic streaking ---Listed on Locel Hydric Soils List Listed on National Hydric Soils List ------other (Explain in Remartcs) Is this Sampling Point within a ~ Wetland? ~ Area appears to drain well following seasonal stonn events 05/10/2004 15:08 25353'30514 SDUNDBUILT HOMES PAGE 55 SAMPLE PLOT _S'-'P....;1~2------ DATA FORM Project/Sile Applicant/Owner: Investigator: ROUTINE WETLAND DETERMINATION (1987 COE WETLANDS DELINEATION MANUAL) Evendell Date: ~:--:-::::--::--------------------· ~M:"'.r.,..,M~i-=-ke'=""R-.o_m~a~no-.---------------County: _H_abit_._at_T_etlh_n_o_log...._le_s ______________ state: Have vegetation, soils, or hydrology been disturbed? Is the area a potential Problem area? YES ~ YES &}) Commun~y ID: Transect ID: (If needed, explain on reverse) Plot ID: 17 July 2000 Pierce Washington SP12 VEGETATION (Note thoae species obseM!d to have morphological adaptations to wetlands With an") nt Plant S . IMjl'<ltnr I l)Qminant Diani !':""'"'es !':lmtum lndl,....nr "' 1. 2. Alnus rubra Tree FAC 3. 4. 5. Rubus orocera Shrub FACU . 6. Rubus lacinatus Shrub FACU- 7. Pteridium ac:,ulfium Herb FACU 8. I <>ercent of Dominant species that are OBL, FACIN, or 25% c (except FAC-). Include species noted (") as showing .• orphologlcal adaptations to weflands --------------------------1 I Describe Morphological Adaptations: Remarks: Cleared homeslte area HYDROLOGY Recorded Data (Describe in Remarks): -Stream, Lake, or Tide Gage Aerial Photograph --other L No Recorded Deta Available FIELD OBSERVATIONS: Depth of Surface Water: o· Depth to Free Water Pit: O • Depth to Saturated Soil: .o.· _ Remam: Deciduous forest ~nd H'J(lrotogy Indicators: Inundated = Saturated In upper 12• Water Marks Drift Lines Sediment Deposits -Drainage Patterns in Wetlands -Oxidi;zed Root Channels in Upper 12" Water-stained Leaves -Local Soil Suivey Dafll -Other (Explain in Remarks) 05/10/2004 15:08 2535390514 lap Unit Name: Alderwood gravelly sandy faxonomy (Subgroup):Dystric Entic Durochrepts Profile Description: Depth (inches) Horizon Matrbt Color (Munsell Moist) 0-4 10YR3/2 4-18 10 YR 413 Hydric Soil Indicators: Hlstosol -----Histic Epipedon Sulfidic Odor ------Probable Aquic Moisture Regime ---Reducing Conditions ___ Gleyed or Low Chroma Colors ~emarlls: .·ield indicators of hydric soil NOT present WET1.AND DETERMINATION Hydrophytlc Vegetation Present? Hydric Soils Present? Wetland Hydrology Present? Remar1cs: WETLAND CRITERIA NOT MET SOUNDBUILT HOMES PAGE 57 SAMPLE PLOT SP12 ,,_ _______ _ Drainage Class: Field Obseivatlons Confinn Mapped Type Yes No Mottle Colors (Munsell Moist) Mottle Texture. Concretions None None Abundance/Contrast Rhizospheres, etc. None Gravelly loam None loam Concretions ------High Organic Content in Surface Layer Organic Streaking ---listed on local Hydric Soils Ust listed on National Hydric Soils List ---Other (Explain in Rernaril:s) --- Is this Sampling Point within a ~ Wetland? ~ Area appears to drain well followtng seasonal stonn events Herbs and Groundcovsrs I Scie11t.J.fJc Name C~on Na.me m,n Pric otv Unit P:rio Otv tlnit Px-io.lOtV 4" pot l dallon Seeds/ca. Achillea m:11letol!Om Ya.now 8 11, 52 Aa.aolutZis n,a-:aanarlta[ Peiarly everlast.11 s ?. 68 Arctoatat')nvJoa uva-u ltinniltinnick s. 2. 27 8 ll.28 Aruncus dJ. oi cu11 Goat I s beard $ ll ,54 s 33,28 Calt:ba oalust:r:fy Ma:reh trar.laold s 14 .19 s lO .'8 Dicsnt~a formosa Bleed.1na heart s 2,27 " lJ .22 S 122. B8 Ji¥JJlObJum aagust1lol F:lreveed s (;l, 44 PrauarJa ch11oc!UJ..lj".1.t Coast stra~et'Yy $ 2.27 $ 57.60 Gaum macro~n-1Jum B.ics-leaf a.vena • l.27 s 51. 20 HttraaJeum la»atum cow narsnin ~ 1.45 llum tenu.1ru: Pacific waterleaf s l.l7 ~ 17.92 Llnaaoa borealls Tlfintlower • a.21 ll l<J. 46 .L11i,l1n.1d Dolvnbvlluc1 Sier-leaf lupine • 6,72 LvsiicJdtan aimarja•11u Skunk cabbatH!I s ll .86 M~ia.nchemum djJatatt Wild lilV or the • 2.l7 NJ/IJlllUs =1e.tat:11s Yellcv monkev fl • l.27 $ 12B.00 uvoeotJJJ l tt• Bntall foraet~ma•not ' 2,.ee O..aat1thd sarmentosa Naur· Da..tslev IJ 12 .SB s 44,80 Oamor&Jza ahJlo.J:lS.t.fi' swaat aic&lv • •U.80 <bcalia o.rea&a.a Mood-sorrel $ 2,27 $ B9.60 .Petaa.tte:11 lr:tqidu• Coltsfoot $ 1),22 l'Ol~um naz,,iaar1a t.a-11 e thumb Jlot9ot11Ja trut1aoaa Bush DOCe.htilla smJlacJ.n» ~tellata so'.J.omon•s Star ~ ~. 27 Stach'Vs coolevaa areat b&conv S 102.40 ~u Jma ff"r4'1d.j.,/J o;r,a P'ringecup s 38 ,40 7ia~ella tr1lol.tata Poau1Uo<,rer ! 143,46 Tolmiea urens1es!J Pi,....,11-baak ula.nt & 2. ::Z7 $ 102.40 V1cl.a gJaball4 Stream violet a 2.27 weD-9oll<IQ11"1UtyWorlorhoetflnol.xll /Sansfflva Area• Bond Quantity worlllheet • Qtv Total c:'o•t s - s -• - $ . s . s . • . s . $ . s . 3 . ~ - s - A - s - s . s . $ - & -• . s . • . s . • - a . $ - $ - Page 4 llugusl e, 1998 co U1 ' >-.> co ' "' co co A >-.> U1 co CD "' U1 w lJ1 w Uj co lJ1 >-.> A 01 § ~ H r --{ ~ ll ~ a, "' 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 58 ·-.. -· APPENDIX B KING COUNTY BOND QUANTITY WORKSHEET Evendell-30 . Wetlend/Wildllfe Report -00062 0 @ ma kiogCcrwlty Deputw:01 ofOi:rtlopm.:ut '1td t!in:irotuutlli.d $mi:~ ,00 Od.ckiaJc AnmieSovthwtsl R,,,tun, WA ..OSS.1219 Da.t• ~ £ 2-CJ/oJ AppendixE: Bond Quantity Worksheet for Sensitive Area Mitigations il'.!Jj,2at_Jl'ga1 t<,,5/V/.// iNlJlOt Nll!Dbar, r.a~•J:imu con tao t;_ llamo, Add_reas, PL.Ul'1' MAT8RIA1.S , I I .t>lant Hatc,rJmJ orJ.ce• Jaolude Jsbar, J..asta.llat.ton. canUai:bora• 111,11.t'ln, ... and' aales t&X, bl.It d'an•t:. .ill("lUd• d1diwry, (1.281 ot 1rhoJ,,.hla pla, 'l'IIBIIS 8cientitlc Name: CotAll.otl Nal'ile Unit l'riC Otv Onlt Pl'ic1 Qty Onie Pr1at Qty unit ~i.a QtY '?ot•J. 4a uot l aallon J Qallon 5 a:allan ~oat. Ables 171"'4.0dJs• """and fir AcH· l?lo1Crol'.lb.Vllaa1 big leaf maple: $ IJ, S4 $ - Alnus robra Red alder $ ll .21 • - Arbutu~ menaJegjj Pacitic mad.rone s 14 .so $ . Betula oanvrj./ara :naaer b.irc:b $ 13 .~3 s . -Prsxinus la~ifolia Oreaon aeib ~ 13 .22 s 23.51 ·.:-/ ,.,N //'/ S 175 .a, .'( P1coa a1~qbeaais• Sitka bP21.!Ce 1 lJ .54 $ 24.lS t/ 5. 0(/ 2 <7 .i "ICO-oo P1nus coJltorta .. Shore aine ' ll . S-4 $ l4, 15 s . Plnu• montiaola• Heste:rn white ~ine ' lJ, 54 s ,4, lS • - .Po-•1us crermuojdss auait1na as~e'D s ~4.15 & - ».,m,1u, tr1choca:t11a black cottonwood $ ll .54 s '23.51 ~ . PruruJ.B eiura.tnata bitt6l" cherry ! lJ,.'!• ~ . #seudotsuaa men~le•! t'!.-.,,,,..tas !'ir $ l3 .s, G :U.51 • 44, 74 s . xaxus brevJtolia• Pac1fic yew • -,.. Tbuia altc:.aca• \olaatern r~~ ceda • 13 .54 ~ 23.SJ ~ 44. 74 17_/l •x-1~.-:,i,, Tsuqa hateronJJvlla• weete,:n h~mlock ~ 13 .54 s 2J.ea s 44.74 • . All pla.ot i,rl.t:aa see trom You~eh Corner NU:rserJ.J1s. 9ound Nati\l'e Plants, seorzrr Lake Growers, and wab.ash natives lt:ontaJ. and Abundant LJ~a lll'J:d Frostv Hollow (&eeds), I I I ! I I I I W<lb-BondQuan~tvl'lorbheotAnal.xll> Sensitive Areas Bond quantity Wllrl<She.tt Page I August 8, 1998 • (5) U1 ' ,... "' ' "' (5) "' " ,... U1 (5) CD "' U1 w U1 w U) "' U1 ,... " ~ ~ H c; I 0 m j U1 U) SHRUBS tll"llit Price Unit Pl:'ice Unit Price Schnt!fi.c Name C'omrm Name 4" -oot OtV 1 gallon Jtl/ • <1allot1 Acer circ.t..aa.tum vine maola s i3,S4 s 23.Sl AIDel analliu alaUol1 servlcebarrv $ ll .54 s .2'3.82 serberis a"'ultolium till Ore<1on ""'aa~ $ 24. lS se~berjs nervosa eh<>rt or-Oil ,1ra1 a .. ll. So Conius st"oJo.nj tera red~osier do......,ooC $ 13 .22 on 9 iJ,51 CO:n,J us aorauta haaalnut • ll .54 $ 23.51 et-ataarn•s doUalasJi blaolt hawtliom • lJ,22 0 lJ.51 aaultherla Bhalloa salal s 1,09 s 13, So H'olodtacus dJecolor ocean Al'.llt'aY s 13.54 9 33.51 Lo.nice.ra iovolucr.s.ta bl•alt twinherrv s 13 .Sf 7..(.1 • 22.97 MVrfca o4.le aweetgale n..zonan.ax horrJdus Devitra Olub s lJ. s, s 24,15 Phlladel<>hu• lei,isli mock orange $ ll.54 • a:2.87 J)bnocal"1'u.9 car,:t ta..r::u Pacific ninebark $ 13.:.U ., t? $ 2l, Sl 9ruaua viiaJaJana choke cherry I.Dvru9 ~USCII wstern craban1'1E s 13. 22 s 23.51 Rh&I!mUB nu.-ah.l aaa cascara. $ ll ,43 • 23.51 ~lld.l:'OJ'J ue ........ hu}jw, P•cltie rhodcdond.rad s U,19 k1bes br1cc~o•uM dtink. currant s 13. 22 R1bes lacustl'B pricklv currant .. $ 13 .86 Rlbes s~-·1neum r~d-t'lowering currant • u. e~ Ros• ..nmannca ma Wood rose • ll .34 s .2.4, 15 Rosa nutkana Noot.ka rose $ 13.54 s 13,51. Aosa tiiaoaa:i"na aluatered rose s lJ .54 6 22.87 ltum.Ja leucodel'llUs black raanhe:r...,r RUbu.s Mrvitlorus tJU.O!blebe....,..., !; 1:l,54 Rubus """ec:ta.bJ 1 j s sal111onberrv • ll .22 1~ • 23.51 SaJJx geve.rJana: aever willow $ 13.23 s 22.87 Salix hoaker1aaa l:looke:r•s willow s 12 ,91 $ 22,87 SalJx lasiaac!ra Paoitic willow s 13 . .2 s 2l.87 balJx •couJerla.na Bc:ouler willow B•llx sttc!u,JU1ts Sitka willow $ ll .22 2.0 6 22. 81 SalRbucus rao~6a n<I el~erberry s lJ.5-t • 23.51 Sorbus sttcbeasJa Caacad~ mountain ash 1.8'\ll'.IIOhoZJcarrMa alhua anowberry I s 13 .2l $ 23,51 V~cc1~jum ovatum eve...,re~n buckleber-1 ! 1.3. 96 VacclntuM aarv1£olJu rad hUcklebe,..,.,, I 5 2. 91 s lS.4'1 wab-BondQU1111~1YWorlwieotAtta1.,~ senSitlve Arees Bontl Quantity worltahset Total Oty Oth&l" ntv <:<in s - $ . • - a . $ 1/7() • le> s -• . $ - .s . ,I 1ff7-f/'0 $ - s . s - ··1:,,q $ tl 10-UJ s -• . $ - $ - s . s - $ . • . $ . s . ' . s -,..,, & U70 -21. !J . s . • - ii . $ Ul:7-"D s . $ - $ - $ - a - Paga :Z Augu,t a, 1998 • co lJ1 ...... ..... "' -~ "' "' "' A ..... lJ1 co (l) "' U1 w U1 w "' "' lJ1 ..... A ~ ~ H r -I a "' r'1 U) ';], Mi en "" Sedaes and Rushe• Scientific Ni!i'o18 Cormon Mam" Unit ttic Qtv ll'nit PricdQtV UnH Pric 4 11 hllt seeds/oz. l <,ollon crare,c aomos• BrJ.atlv eedne s 1.32 carex lent.tcular1s Shore se..,.,a $ 1.Jl Carex l tmnhve.t L\ITlnbV &-.rlne s l.32 carex cb.at.u:,t.a s1oua11.. ae4gi!!: s J.. 32 !; 19 .20 Ca rctx rostrata (utrj B&akl!d :sedge: $ 1. 12 Cilrex BtJ'l'ult'a Sawhea>c sedo:e s l.32 B1eoaharts ac1cularl BD!kerush Blaochar.ta t:tal12st.8'1s Cociaion Soikerush s l.Jl Jtuicua acumJ:natus 'l'atiered ru.sb s 1.32 ..n.tncUB artJaulatu~ Jointed ru11h 1"mau6 eftullutl (var. p,acltJ Soft 1.'\lBh s l.32 Ju..aous 11.t1BJfoJJ.us DaO"tJer leaf rueb s l.3l J\J.aCUB .-.--rJ.a Pointed ruab • 1. 06 s~:J.-11• ac1.1tu1 HardatsM bUln.teh • Ll> $ 2j, 04 Sci.mus marltimus Saltmarsh ln.tlzus1 s l. 32 Sej.rnua ln!crocarnua Snl&ll-rrtdted ll>ll • l.Jl Grasses Scientific Name COTnncn »tune unit Pric• Otv thlit. Pric• Otv Unit Pric 4i, got. 8eeda/o.z. 2 aal.lon AJoneCUl'IJB de£tUBl1S Short-awn fOlttail . Alooecurw, aen.lculat water foxtail s I. 00 aeabt.Ulo.:La 11vaj qachn ~eric:an aloucmgJ s ,.ao $ 3.04 Cal4tna,arnst1s canadfflJlfi B1ue1o.int reedrn-ass CJnaa latUol.la wciad reed J)elfi:thJ1 .-.,t,s Ca.tJSD1 t'.O TUtted hairg . .rasa s L06 s 9,60 al vmus glauaus Blue wil~ • 1, 36 Peacuca JdabOeGsiB Idal1a tescrue • l.52 Faetuca·rubra va~. r Red fe$'cue $ 4,79 Gltft".erja bore-lis (o )forthern mannacn.-aas s 1.60 Olvce.r-J.a elaca Tall nnmnaqrass I $ 1.45 s !.60 Pa.n1cum oaaideGtlle He•tern panic•CJras11 Ve.nu, SaJ. encJ.t 1c Name Coll'l!l1on JJaJne Unit Pric 01:v !init ~:ric Qty Di'lit hie 4 11 not l aallon 2 crallon Atb~lUIII tilJJl•f•mJ• ladv fena s ll,96 Sl•choum sp1caat deer f@:rn $ l). 86 Dl>"'fl'l"lnt;erls .. ~ ... sa shield te:rn s 13.St Polvatiahwn muaitum \re&tern sword ta>:n • 13.86 Pt6rJdJum an.•111aJ111 braoken web-iloodQ""'1Ul'/W<rbhootFTnll,xll SensltlVe Areas Bond quantity worN&heet Qtv OtY Tat.al Other Coat s . s . s - s . ~ . s . s . s . s . $ - s . s . $ . s . $ . Qtv Qty Total c:ose s - s - $ - $ - s - .!I ' s . " . ~ - s - $ - I; - Qty Qty Total C:..at $ - $ - •• - $ - $ - Pl!ge 3 Auaust B, 1998 • <S> (J1 "-... <S> "- "' "' <S> ,,. ... (J1 "' CD "' (J1 w (J1 w cl) <S> (J1 ... ,,. (J) ~ gi H r -l ~ ~ 0, ... INST ION COS'l's I LABOR. gnTJ'IPMBNT. OVEaimAt> ' l'Yllo I Unit J?iio Onit Corrt11o•t, vetJ41table, del!'\J'ered and B1'l' $ )1,88 <:'{ Deco11mactJrtO" t!ll/hardi:lan, ma.d.ium, to s 1. S1 (:y O.c:-.nacting till/ba.rdrMln, medJum, to s I. S1 ~ Pertiliae, slow release tablats, 30gm s 3.21 Baoh Rydraaeo4ing I s O.Sl S'i Latlor. rfAnera.l (land•eanjna) ~ 25.00 mi Labor, general lconatniction) $ 31.00 !Ill Labor, consUltilnt, suner1risina • 55.00 11B. t..lbor: Cona~ltant, on-site %B 4 des!nn ~ 95.00 Ill! Fl.ANTS, Petted, 4" diamattt, medium $ 0.68 racih PLANTS• ~ntaJn•r, l aallon. mediU111 s • 10. o, Bach PLAN't'.9; Container, 2 qallon, medium• $ 16.47 Bach I.. (1 6n Pt.Am'S, Container, 5 gallon, medill!n 1 s 2!'L3B Hach ~ ,, ,:,.- PLAlfTS1 Soed.i'""'· \..tr hand • 0,44 SY PLlll'lfS: Slins (wf.llo~, ~edwOSier) • ,l.Jl Sacb PI.Al'2"S • stakes ("1llow) $ 0 .96 Bach l\ental of decoffll'lact1ng machinery & on $ 70, tiS !lour eand, coarse bu.tlder•B, delivered and s 41. 06 CY Stak.ing 111ater1a1 (ee.e ~r t.xe.e) s 7, 00 B~cb SU.rvevina, line & arade 5 605.U DAY survev!ng, lot locat!on & lines $ 1, lSl.50 ACRa Survevina, toaograabioal s .:z,uo.oi;, ACl!S 1'111 f._. t,..,.,aoil, dillk: l:iarrow, 20MI cnetl)t-1 • 1, 02 Sl OTl£lrR COSTS -TmlOtJ'CJHOU'l' !!NITORINQ ~RR!OD ITI11>9 Unit Pr.ic:1 O'nlt 1n&neotion, annual $ 460, DO BACH Il'UhleCtiOJJ, final S 575. 00 SAC!! kaJntenanc:e, s61Di-ann.ual Maintenance. :a.nnual Noni tot'i ...... , annual I Wateri~o, in or "11ater 1 60' aaakar hos s l.62 MSF Irricaaticm -temnor• ~ $ 1.000.oc Acre trriqat10n • bUl'ied $ 4,soo.oa A.ore w•b· Borr1JQuanUtyWorkett6$Rt'lll,xl1 sensitive Al'IIIIS Bond Qllllntlty Wol'ltatleet ROirITl 'tOl:6l s . Ii . /J . s . /J . • - $ - s . g . $ '7kY. z.o e 1fL rrt ... O(} s . $ - $ - $ . s . s . s . s . • - 'l'Ot&l s ilbt70-CI; s S"7f-oo • . $ - s . s . Page S Augu.t B, 1998 • C, U1 ' .... C, ' "' C, CS) A .... U1 CS) 0:, "' U1 w U1 w U) CS) U1 .... A ~ ~ ~ H r -; ~ (J) ~ iii en w HABITAT STRUC'rll'lt'ZS fiaoludea deli~ervl I'l'BMS I Unit t:ost Unit faaoin11a (willcw) I 8a<:h Log,' (O!!id~~), w/ roo; wada, 16•-14• dia~., S 1,ooa.00 lilach tog~ (cedar) ~/o root vada, 1C'-2t~ diLtlll,, s 410.00 llacll r ....... o, tt/o root:. wad.a, u;n-:24 11 Uam., to• lm1 ~ 345.00 B'acn. I,oga v/ ~ot v&da, 161 ~2-t" dlaru., 40' Iona • 4.60,llC Jach Roc:kt1, omi-man $ 60, 00 Bacb iock.a, two-man 8 B5,00 Baell Root wads s tG3.00 l:l'ach Snawnlna t:11"&ve l, c,,...-e A .. 12.00 CY weir -log $ 1.,00.00 saoh Weir -adiUata.ble & 2.000.110 Ba.ch " ' WOodv debris, 14'""8 • 16l.OO Bath :l snaus · anchored S 400, 00 Bach ( SYl'"""S: -on site: ,(, "' SO.DO B'aCh ~ Snaas -i.........,,rted 9 800.00 ilach DOSIOff CONTROL HBNS I Unit Cos:t UnJ.t Backfill and COll'l.naction-ernbfm>tn\ent G 4, B9 CY Crushed au~faeinqi 1 l/4 1' minus $ 711.JO CY Ditch.Ina s 7.0l <:'/ llxc:&v.lCion. bulk s 1.30 . C't .. l &'ence, a!lt 9 1.20 LP !:JO (J Jllt.e Hash s 1.26' SY MUlch, bv hand, straw, 211 deec • 1,27 SY Mulch, bv hand, wood ch1va, 2" cle.tv $ l,25 SY r-tulch, bv maohJne, straw, 1 11 deeb · • o.n SY Pi'Oifln, tAffl'nor•'l"V, CPP, 6 u s 9.10 LP Pl1>lng, t-ora:rv. CPP, a• 5 l4, 00 tr fiDina, temnoraru, CPP, 12~ s l8. 00 LP Plastic covar1~, Eimn, tllick;, Sa.Ddbal'.I" • 2. 00 SY l.iD tao, machlnEI placed, alopes 8 J3.9e CT Rock constr. sntzance 100 1x1s 1 x11 $ l, 541,68 Kach Rock Const~. lnerance so 1 x1,1 Kl' $ 1,.271,14 a,,ch Sediment. ncnd :daer as11emblv ~ l,i9S.U Saoh Sediment t%a"ti -5 1 high bel"l!I 8 15.57 LP' s.u.meat trql, 5 1 high bU'III w/api.Uway incl • 59.~0 "" Sodding, lff deeD, lev@l grcund $ 5.24 SY 8ciddi.na, 1 1• de-, sl oaed around • 6.48 SY stra~ bales, nlace and remove $ •n.oo TOIi Tonsoil, delivered and enre4d s 3S.7J (:'{ I web-BandQU1ntt1YW0<iahoelflllol.lds SensJtlve ANISiS Bond Quantity Workshut .- rotu $ . $ . ~ . a . $ . $ . . -. $ lllf'r-CO /!,(!.On Tot41 s . $ . s . $ . 3 bOO-CO $ - s - $ - s - $ . $ . $ - s . $ . s - $ . s - ~ . s . $ - s - $ - $ . Paga6 August 8, 1999 co U1 ' >-' co .... N co co " >-' U1 co 0) "' U1 w U1 w Ul co U1 >-' " U1 I C H r --1 I ~ U) '1l ~ fT1 "' " G!NllltAL rTlOIB I Unit Cost unit 'I'otal Fenclnq1 chain lJnk, 6• biqh s 18 .89 LP s . rencina, ebatn lihk, corner posts S lll.17 Haen s . rencinQ, chain link, gate $ 277.'3 Bach $ . Penoin~. snl!t rail 31 htoh (l-~ail) ! 10.!4 LP a . i'encing, temtiorarv (NG!)b} s 1.30 t.r a - Slrm,s, se11sit1Vfl axes. boundarv s 2.5G !ach $ - STEEPS LOPS 'sLOPl!I rNSTABILrTY Wll.ITl!I-IN rTBMS O'l'HBR NOT3: All plant pric:ea ll'e tl'OII\ Storm Lake O:rowers, l'iabaah Natives, Fourth Co1ner, and sound tta.tlva Planta (containtt.ri) , and from i'ro~tv Hollow--and Abundant Lile (seeds) . lOt CONTI00211CY & MOBILIZl\'!'1011, TOTl\L, wal,•SondQuonlltvvtorb'-tFJn,l.m Sensitive Areas Band Quantity Worlltthee:t ~ IP~·-'i/1 $ /,l00").111. $1/37{,.JZ_ Paga 7 August 8, 1998 " CS) (J1 ' .... CS) ' "' CS) CS) " .... (J1 CS) OJ "' (J1 w (J1 w uJ CS) (J1 .... " § I ..... r -< I I o . 3' Cl "lJ ~ en (J1 _i_ --1 --'- _..._ --1. 05/10/2004 15:08 • I ,i: i' !,.. ... .... , ... ~ .. , ,.,, .qi ...... :,1 iZ! I .,. :,! ci! l;! -.:! .. I :S! 'Cl .,,. ... , I i i i i i ! - _,,,, l:DIMR"~. ~ .. -............ """"""" -- £j ~ '" l\l ~ .. 2535390514 SOIJNDBUILT HOMES S~ 1_/4 S14-T2JN-R5E PAGE 66 ~ ' -- I . R-4- I _@.J _@L -,r-I --=---r - J I _L __J U&IMI~--. --.. ....... Aoidl."' amm, ..,,,.... ----·-Zltfl',ftQ',.111!. _ .. _ ,.,,_ • I .. .. I _J SIQll'IIQ.111S11111lil. ... .. - --+- i J._ ....... oc CCUff'r ..... 'llilllmlllCTGI fCl,1 'Ol1111 AMt:IUl!Tl'lil!1*'1'111am ---------- I e SCAU:! 1~ • too' "'" 0 100 1 R-4 -ml9!Ulllatar-------~--=-4u, l. Cl\111), WEllAMD 'ILi. • 200 SO. tT. 'Z. ~ BUFFER Dl'rn.lmw.tt A. r!'f R.O.llf. • 4,940 SO. ,n, B. SY .l.O'f!I • 11.3-40 so. rr . I J, ~ eu~ A£PV.cDIENT/AVEJW..1NO AA£A • 1$,....0,5 SQ. fT. 4.. C:::::::> 8Ul"F'ER CNW.HCCMCNT ~ • d:S,000 SQ. F'T. (IF R£Q'D) {TO El£ SEl.ECTED Err BIQLOGIST) . :S.l.T. 'O' A. eu,nn AAF"A • !lD,o,:e SQ. FT • D, '¥£n..AHO ARD. • 1~09Cl2 so. FT. f'ERMET!R ROW Jl'f£J,. • 24.HJ SQ, ,T_ Nl!RIOR PUSUC R!Wl AR£A .• 5!.809 so. n. tn[l::IOR F'RIVATE ~ AAEII a 179'25 SO. FT. STORWWATER Oi!'OmON TRACT V .IJU:A. • 4,421 SQ, FT. S1'0RMWAT£R DtmlnOM 1MCT "'W" AR£,I, • 3S,BJ!i S:O. FT. REC~lJON nw:T '\." •~ .. 14,871 ~-n-. ~ o! r:Toa ~ ~£ OF' 1t,0 '!'&A WAnn SURr~ <S ' -r 0 1 i "" ., " ~ " .s II' •o .., ~ "' .. \ " "{ "'t •• 'o ~§1 ' -~ 1 ~i~ ~ ·~ i~ It \<' ~ .. -t 0 © .. ,:: • ·~ ~ Jr J! ~ I , I if "1-} ' ~ lt 1 h-, "' • -f' . " •o ., i :J ' '1 t ~ "' " "' tr f " 't ' ' ... r - I ~$ ·~~ i /J ~t ' " i l I :J < 3 i ~ .~ J ' •• ~ ~ ·o I • . ·-·-· ... ....• ,,__ ""i ---~ . Ff 1, J ~ I " .. );\ I ~ 'o ~3 I ~· "' ·9 <' ! "' ' ' - ''\,,,J;l./" l.Lt: .. ~ 9! ,.~----.-,1,rl-----hl ~l i 111---~--,i!t,_,:)-. ---,.aji ,. l-'r..ocl,l~F---. _-till-c \~ ... ''-llt-"1'WC.,,..,,.· ® 14----~f---'--lilr-,llr~ . I),~ :£'1 . ·~ :7.1 Jt-!-.. ""o=-,r.~=,.,_-.1_1,-t,s,-.""o::=-,,,_.-, -,h~ 1~ { =- :, J .. l· j I I 1 • I I .I II r1 .. ·11 'I lJ . I Ir ~1.1 !I 11 11 p.,=:::;,--iJ ..... · -.... 0 ·- V) "· II') . a:: c"' ::> Ill' 0 ::> I J: 0 .... >-N IX) . .... .... uJ I _,g§ g -' u.. a, <Cw I um~ I . ! ' 07/14/2004 13:07 2535390514 Bruce and Joyce Osgoodby 1345615~ Ave. SE Renton, WA. 98055 206-200-6612 Dear Bruce and Joyce Osgoodby: SOUNDBUILT HOMES Confirming our conversation today, you grant the developer permission to enter your prope ,ty for the purpose of installing a rockery on your South property line and re-grading your driveway to match the elevation of the new proposed roadway in the existing King County 136"' Ave. ROW. SBI Developing, LLC further agrees to re-gravel your driveway after the re-grading is completed and install a new 4ft tall chain link fence along top of the newly Installed rockery. Your signature below indicates your agreement to grant the developer of"Evendell'' permission to perform the worl< described above. We will do our best to minimize the impact to you during the construction and will communicate a timeline for construction to you as soon as one is defined. Your cooperation in this matter is greatly appreciated. Land Acquisition, Mgr. PAGE 02 - - 10/04/2004 17:10 2535390514 September 27, 2004 Bruce and Joyce Osgoodby 13456 156'11 Ave. SE Renton, WA. 98055 Dear Bruce and Joyce Osgoodby: SOUNDBUILT HOMES PAGE 02 Confinning our conversation today, you grant SBI Developing,LLC and its contractor to enter your property for the purpose of reconstructing a keystone wall located at the Southwest comer of your property. As discussed, we will step the wall back to your fence. Your signature below indicates your agreement to grant SBI Developing and its contractor permission to perform the work described above. Your cooperatkr11 in this matter is greatly appreciated. Respectfully, ~- Land Acquisition Mgr. .tJ/w<-U' 2 o ~l; Bruce Osgoodby ,J,, I - 09/01/2004 15:04 25353'30514 SDUNDBUILT HOMES PAGE 02 Recording Requested By And When Recorded Mail To:Mark Sollitto coNFORREll COP1 ~ .. ~· 2004,j!!~~i.~33 ~ ~iGl!"~~t ~~13 King County · ~:.A'~UNTY, "A Transfer of Development Rights Program Water and Land Resources Division · CONFORl'IED COPY 201 So. Jackson St., Suite 600 MS: KSC-NR-0600 Seattle. WA 98104 Transfer of Development Rights Certificate Number: 78 Fl'AGE881 OF 091 20 URBAN Development Rights Date Issued: .July 29, 2004 · Certificate Issued To: Name: SBI Developing LLC . Address: PO Box 73790 . City & Zip: Puyallup. WA 98373 This development right(s) is/are transferred from the following certified sending site, pursuant to K.C.C. 21A.37: Sending site file number: A98V011 o Granter: King County. a political subdivision of the State of Washington Parcel Numbers: 332305-9002: 332305-9062:282305-9101 This ce0rtifies that SBI Developing,LLC owns twenty (20) urban development rights removed from the sending site identified above; which has been qualified as a transfer of development rights sending site pursuant to K.C.C. 21A.3T. · Receiving site tax lots: 142305-9009 &142305-9022 ODES File# L01 P0016A & L03RE038 The official record of these development rights is maintained by King County.' If there Is any discrepancy between the number of rights identified on this certificate and the official record, the official record shall control. If any of the development rights Identified on this certificate are sold, conveyed or transferred, the person acquiring the rights shall within ten (10) business days deliver to the King County Transfer of Development Rights Program this original certificate. A new certificate in the buyer's name shall then be Issued. The development rights may be used only on a receiving site(s) that has/have been given final approval for additional residential density achieved through the transfer of development rights in accordance with King County Zoning Code (K.C.C . .21A.37). Approved by Representative of the King County Transfer of Development Rights Program lnteragency Review Comrrittae Signature ~ Certificate Number ~ Date 1Ssued ]I 29104 PagC! 1 of4 1)<, \ - - 09/01/2004 15:04 2535390514 SOUNOBUILT HOMES PAGE 03 STATE OF WASHINGTON) )SS. COUNTY OF KING ) I certify that I know or have satisfactory evide~ce that /iw,«:-5o, ~, f''-1=>. . is the person who appeared before me. an,d said person acknowledged that he signed this instrument on oath stated that he is authorized to execute the instrument and acknowled~ed it as the Program Manager, Transferable Development Rights Program of King County to be the free and voluntary act of such party for the uses and purposes mentioned In the Instrument. Dated: 7/-z_q/e'f State of Washington Residing at 1.4-/'S<.JAI My appointment expires r, /'S.,/o;; To Redeem Development Rights: . In applying for receiving site approval, the applicant shall provide the Department of Development end Environmental Services with either a copy of this certificate Issued In the name of the applicant or a copy of this certificate with a signed option to purchase these development rlght(s). For rec!='ivlng sites within incorporated municipal jurisdictions. the applicant shall provide the above documentation to the municipal jurisdiction and shall follow that jurisdiction's development application review process. · Before building permit issuance or before final plat or short plat recording. the applicant shall deliver the appropriate TOR certificates issued in the applicant's name to the Transfer of Development Rights Program. The applicant shall receive an extinguishment document showing that the development rights have been applied to an approved receiving site. The TOR Program shall.confirm forDDES or the municipal jurisdiction that the requirements of K.C.C. 21A.37 have beer. met. Certificate Number 78 Date Issued 7/ 29104 Page 2 of4 - -- - 09/01/2004 15:04 2535390514 Recording Requested By And . . When Recorded Mail To:Mark Somt,o ® '. SOUNDBUIL T HOMES CONfORIIED COPY 20@l~@)ijjlj!,(QJ)@)i53~ ICC w:IT'fR &, LAN ET"ISC e.ee :;,!!,zei~ ~:~,. KtNG COUNTV, UA. King County Transfer of Development Rights Program Water and Land Resources Division 201 So. Jackson St., Suite 600 MS: KSC-NR-0600 Seattle, WA 98104 COMFORHm COPY PAGE 04 Transfer of Development Rights Certificate Number: 79 PAGEH1 OF N1 8 URBAN Development Rights Date lssu~d: July 29, 2004 Certificate Issued To: Name: SB! Developing, LLC Address: PO Box 73790 City & Zip: Puyallup. WA 98373 This development right(s) ls/are transferred from the following certified sending site, pursuant to K.C.C. 21A.37: '; · ·· Sending site file number: A98V0110 Granter: King County. a po\itlcal subdivision of the State of Washington Parcel Numbers: 332305-9002: 332305-9062:282305-9101 ' ' This certifies that SBI Developing, LLC owns eight (8) urban development rights removed from the sending site Identified above, which has been qualified as a transfer of development rights sending site pursuant to K.C.C. 21A.37. Receiving site tax lots: 142305-9058 DOES File# L03P0015 The official record of these development lights is maintained by King County. If there is any discrepancy between the number of rights Identified on this certificate and the official record. the official record shall control. If any of the development rights identified on this certificate are sold, conveyed or transferred, the person acquiring the rights sh·all within ten (10) business days deliver to the King County Transfer of Development Rights Program this original certificate. A new certificate in the buyer's name shall then be Issued. The development rights may be used cnly on a receiving site(s) that has/have been given final approval for additional residential density achieved through the transfer of development rights in accordance with King County Zoning Code (K.C.C. 21A.37). Approved by Representative of the King County Transfer of Development Rights Program lnteragency Review Committee n{._~, Signatu~ ~ Certificate N1,1.mber 22 Date Issued 7/ 29/04 at Page I of4 !}<, : - - - 09/01/2004 15:04 2535390514 SOLJNDBUILT HOMES PAGE 05 STATE OF WASHINGTON) )SS. COUNTY OF KING ) I certify that I know or have satlsfactqry evidence that Mark s~mtto is ~h';' person who appeared before me, and said person acknowledged that he signed this ,nstrur:nent, on oath stated that he is authorized to execute the instrument and acknowledged ,t as the Program Manager, Transferable Development Rights Program of Ki~g County to be the free and voluntary act of such party for the uses and purposes ment101'\ed In the instrument. Dated: 7. /7-'i Ip "1' Tb Redeem Development Rights: State of Washington Residing at &.,,.rS7' • ,J M 0 y appointment expires coMw In applying for receiving site approval, the applicant shall provide the Department of Development and Environmental Services with either a copy of this certificate issued in the name of the applicant or a copy of this certificate with a signed option to purchase these development rlght(s). For receiving ·sites within Incorporated municipal jurisdictions, the applicant shall proy,ide tho above documentation to the municipal jurisdiction and shall follow that jurisdiction's development application review process. Before building permit issuance or before final plat or short plat recording, the applicant shall deliver the appropriate TDR certificates Issued In the applicant's name to the Transfer of Development Rights Program. The applicant shall receive an extlnguishment document showing that the development rights have been applied to an approved receiving site. The TOR Program. shall confirm for ODES or the municipal · jurisdiction that the requirements of K.C.C. 21A.37 have been met. Certificate Number 22 Date Issued 7/ 29/04 Page 2 of4 ,dNG COUNTY. WASHINGTON i'(®i ~g~a~~~~N~INE -Nl'l. _L03LOO 13 APPROVAL DEPARTMENT OF OEVELOPIAENT AND f/MRONMENTAI... SaMCES ~OAY o,\:.)J!I~, '"'* R ~TT\NG UNIT. LAND US£ SERVICES OMSION KlNG COUNTY DEPARTMENT Of fiSESSMDITS11,,J!,.... EXAMINED & ilPPROVECl THIS '?J:M-J_Of ~. 2'Xi!1 .::,..,tUlab.. 1f1J1~ th,,;,, KING COUITT'l' ASSESSOR Qfi'IID'~KJti!L.CIJJJtlljSSESSOR APPROVAL NOTES: THIS RfQUEST OUAUflES FOR EXrMFIION UNDER KCC 19A.2!!. IT DOES NOT GUAA./\NTEE THAT THE LOTS WILL BE SU1TABL£ FOR DE.VEl.OPMENT NOW OR IN lH£ fUIUR£. THE l£G.<J... lRAHSFER Of THE PROPERlY t.lUST &. DON( BY SEPARATE INSTRUMENT UNl£SS AU. LOTS tltRElN I\RE UNDER THE SAME OWNERSHIP. RECORDING NO VOL., f . .o.(;£ 11_lf/.2.01 I PORTION OF !Ylf 1/4 ol _§f)__ 1/'4, s.H. C~N .• fi_Q_f. .. W.M ,,, •. --.... DECLARATION Kt10Yr1 ~WI 81 lll!<SE l'll£SOml TW..T,'''E TH£ UMDERSIGNEtl"OWHE"R(S) Of lHE l.AllO -~ DO t£RESY MAKE A BOIJNOAAY UH[ ADJUSTMENT lHEREOf PURSlWff TO RCW 54.17(),10 Of TH£ p,',M:E,. N<1D ~T SAi() J.O.il/SlW:N"T IS~~ Tl£ FllEl:'. CONSENT~ IH• ~ M~,lHE OESIR£S Of TIIE OWNER{SJ IN 'fflNESS WHE!!EOf" WE W.~ SET OUR 11,1J,j1JS Al«l p:;~,.r.s ~ TO EIE TtlE GAAPHIC REPRfSfNTATXlN . ...-: ' -' '-· .. " 0 l,l.f\q,M,,,,,,_ ~·, , ,c/ifl, {v1' .. , I 1 ~YJO ~',!,f;! 2ffa,~• -~~· ,,,0,a, ' 1 •. ~-01"4-,,, ~-;,J ~" .... -::-:~~~~-. . . -.4, , . __ .... ~ ~~--P1i: ;;_;:"~:~r:li~~~a;',-!-"' -_/ /c ~~:,D·· ; .,. .... -;."'" STATE OF WASHtHSTOH. f ri:;::\--, \{-.. ~_)) ,,[c,;·~ On tnlll.day person•~,l'I appear':_11'1>atore.., ( \ ~'lj.l) RO!£R1 i... M.>.IR mo .CL'rtJER.1,E ~ • .•• ~--(~~ ,l to 1111 know11 tc be·"tfl.e. ln<1b.iduals dnc.1:\b•d in~-wha ··-'"'" •,t~ CDUNIY OF '°Pfe.tg,e._.. On tllh day p,rsondly eppHred befarq ae n,.V[) J... NYBUlM NflJ D£8RA L AUllSO :~:~~~j~d!~~ r~!~l~h::"ttrn:~o~: !_~~l'~~~;e~~;l'O:B .,,,·.· ./ ,,~"-,~ and voluntary act and deed, f<>r t/1.C"~·us _5 and_;P'urju.-.•· .-:·· ·'· J .,,~.~, .... ~--,..-" nar11n aentlon•a. L/-'.'-~ _:· tf :~"';.,:!, 7f.V}j" I"._ • :'7,~!-0.fr ~,;~tment -'/O-O~ . 4 c,· .f.~~'. _J:·'·' OLD LEGAL _.ri'EscRIPi'it>Ns l.OT " {PAACEI. 0423re ~-=· 103.~:D 6q ft ·-:·. ~hF~tt:~r~rn~\:ALF~rn™flW,tc;1~if'~~=~-~v~~~TCF~ElJ1.smu IWUIN fF r.6tn Avel..E.~ 1.5 (EEDED_f() KDCi 'CtU,TY Err i:t'EI) F£m«0 1.KEJ1 KD<Ai CllMfY IEXmlJ<O NJ. 1094<',Q; TIXiETl-ER WTTH i tof-~ EAmei1" FIFI nq£SS. E~ AN'.l urn..rrJES OVER. lKER Al'<l ACRES nE. NJITH 15 FEET CF Tt£ \EST .·.le7 FEET llS.flE.I.SlRBl FF04 M EAS'TtR.Y IW'loIN D' co..tITT RWJ RIGtT---{F-WAYl CF LOT 2 CF SiG!T PLAT tll. 87~\ill. AED:HEI \l'IE>I KlN> q:pllY FECCFql}I; l<l. 0002Zi0639. ~ Cf' KING CXU/TY, ~Tat ALSO TOOETl£R 11ritt ~ ~EXa.=.i13l\le e~· FCJl uuei EGFE$S AID UTlLITlEli OVER l.t«R llt(l ~ Tl£ =~~{tl~~,fi~~;c~IF~~T:~n£~~~k~:~~t;t, ~J:.y IF~ ~s?rir;:~·~I(}I J~}~,r~ 1am; PNG:'. !I E.l51":tJ4. LYIUi [.OSTE!I..Y CF THc ·.,.. .,· ,. SITUATE IN TI«:: COOl,I_IJ IF KDG, ST A TE CF ~OOTCtt :· . ~~;~=~y~~i=:={~:;;:.:=::;.::;:. ; E£GIW"IN3 H TI-£ SWf/£.0.ST c:i::ff,U! CR SAJO asT HAU'·.~ TIE !fJIIDIE51".~·Cf' TI-£ SQJlH"!'5T IJJ.tal:El:I .·: At<! nE TIU: PIJJl,ll IF 8Ei.J'.Ml.1N3; ~ tam, 2!1"21' asJ.'23.!lli fp,,..Mc.Q,G :i:1-£ EAST 13,£ IF SAID EA5T·c,,,,:· IWI a= TIE ,am-tESl' lJJ.l,RTER Cf' TI-E swn£I.Sl Cl.lAR1ER TFDa·rarnt 88'07~· !EST jl53.6J FEET TD TI-£ •. \ES"T UH: O" SAW EA.ST H,tU' fl' nE l'Ol'itlEST l1JolffiEil IF TI-£ SClfl1-EAST ~ TI£Hq;: SClJIH 0071'05" )€ST 525.82 FEET TO nE SWTH Lll>E CF SAID EAST Hl,Lf IF nE tam6ESJ Q.JAITT.EA CF ne-~ o.mmR; Ti-£1CE gJJJH 00"17:.S" E.l.f!T ~S4 FEET Allffi M &l!TH LDI: CF SAID EAST tJ,,\l.F CF n£ IOITHWE!,T•aJARTEi'I • CF TI-E roJTIV.ST lllWlTEFI TO TI-E Tfl.E POINT IF IJ":6ll'Ml·ll:. •;. ·:,· :. Al-0 fXCE>T C(UITY RWl CCJ,'\EYEll TO 1(11'<: CQfflY BY CEED fEClHEl !HER 1(1.',6 cn)IJ'f IEIRlOO tcJ .• ~ :: SllllllTE lN TIE co..tlTY IF K1Ni. STAIE CF IU.S1ThlJTC!~-·:,,.,,,., •....•• •' .·.· LANO SURV£YOR'S CERTIFICATE ··.·."·-···· RECORDER'S CERTifJCATE . _ 11:0, FILED FOfl RECORD nns ~ .... DAY OF l~ 20<:l!,\. AT ~M, LN BOOK .ti!Lorf ... ~ P~EJ!):/..AT rnt'RtauEST or lHIS aoUNDARY UHE ADJUSTMENT CORRECl\.Y REPR£SENTS A SURVEY MADE BY ME OR UNDER MY OIR£CTION IN CONFOIUAANCE WITI-I STATE ANO COUNTY STATUTES. G. PHIL SARGElfT ··~tic· lj .' .4~ JA,.,.,j ii..d"{~ ' .~ ··~twr:·tir··tffC"CIR ~ ..... g;_ C)Jl;p '1,,...Jl ,-ts--~ C. PHIL S,ISiCOlr ~414S llATE . 3>'. /:T 8 }~=~Ji:'t:~~~,~tTE~j) LE~~~,:-''o:?{RIPTION Tt-E EA5T l,ALf. al TI-E tollf6EST llWlTER IF JI£ .SClJTlEl,li"f"'lll.WlTER i.f' SECTICf<I 1o4. "ltVB-UP 23 IOffil. i:w,a; ·.-!I ~pt w.11, ::· --········;, ,. ' ,·:' -·.,. <' ·: .. ·.· :: -· .. ~ ~ Tli\~~·~~OOH; ~~~--Wt.RTEJI CF TIE Slffi£AST <l.LI.IIT6l (F SAID wtel:00 A~. ti-E-t,Qffll.;:~~ CF oi,"~ ~T WfftlEA CJ' TI£ IQUl1£ST •W.IRTER IF TIE oo.m-EAST aJ.\ATER; TfEtCE $'.lITH 00 1" IEST . .ut-G TIii: EAST L~ OF SAID !JllJTI-EASl QAATm. 135.65 FEET TO Il£ BE!l!NIDG CF SAW LIN:: t{Rftf111w.ea· !EST. eJAt.U.a. wm1 n£ IUnl-J LltE CF $.,I.ID samu.ST WARTEP. CF TI-E IOITT-tEST Wt.Rla>,d" Tl£ !?/llEII.S"J Q.W!Tm. 653.61 FEET TO TI-£ IEST LDE Cr SAID EAST KILE CF Tl£ IG'ITHEST WI.ATER CF lt£ 5Q/p£lsT IJ.l!fITTR .t,/,lJ Tl£ lEFN!NJS CF S,l."Dl tD-£. ~ ~ w.mr RllO ~ ro Koo ~-,,-ft:EEo llEO:FCEiJ lHEl l<INi a:urrr 1£CCRJW. 1-f:l. 2600004: 511\JAlE Jli TIE Ollm' Cf KOO STATE CF ~Teti. SURVEYOR'S NOTE Tl£ ~ l.f!.iAt. tEDll!'TID,t FOi LOT B HlS ti!{ lfillTEH lfi£IN WITH TI-£ lKID{J IF RlMlKI.TitG TIE PUSSiaE ' HIATUS aErlEEN TIE Sil/TH LDE IF TI-E PfU'EHiy IEfEIIII CESCRl!El AH) Tt£ r-amt LIIE OF Tl£ ~ \otltIQt .lll..OINS TO ti£ !lllIH. Tt-E P0SSIBD..rTY IF A HI.llll3 IS CIUEl BY A DlFFE1£>iT START1N3 POINT FOO Tr--E f.lllD>TIGI TO LOT a nw, Tl£ ACTUIJ.. oem i::e;i:m;,r~ FOO THAT EXCB>iI{J-J. nus ~ DE!DIIPT~ DE5D\T8f~ TI--£. tmll1 LIN= OF TtE EXW'TlCtl IN TtE SAtE HNffR .lS TtE CEel Fm THAT EX03>TU11. Tl£fEn' PRITECTINi Tt£ lMlcGITTY NO amu...,m CF TIE L£EAL IE5CRlPTI!),6_ _;···.,.EASEMENT, COVENANTS, AND RESTRICTIONS: /iROM ~~tiATWt!.?.Tl.E INSl.lWIC~ COMPANY SUBOIVISION GUARANTEE Ho. S70B90 ITEM 7. EASEHEMT: ·:.&RA.NTEE; KING ca.trrv WATER OISTRJCT No. 90 ":P11RPOSI":-•. ,IIATESI AND SEW£R MAll-fS ·Af!EA .&.FFEt':TqJl; NORTHERLY 30 FEET OF PARCEL B :-· :: RECORDED: J!;ILY i7, 1975, AECOAOING No. 7507170567 ,'!TEN 8 .• '1!:.i.SEHEHT1"''0RANTEE: KING" COONTY WATER DISTRICT Ho. 90 . PI.JtPOSE; 11µ9i AM> .• 5Ei1EB..H.l:INS ~A AfFEt;.tED: _t-llATHERLY 31)".fEj::T OF PARCEL A ,· •. 0CCORDED::: .J,l),.'1".17, 1975. AECORCl~tfG NO. 7507170570 ~ Al"ln.lD1ic, b)' 11...-c.. >1,:,. ITSf 9, EASEMENT: ·.'!:RANTEE::"-"PIJ!>,ET SOUNO POWER G LIGHT. 2.00+ P6'~ .,-ooc1<oo .. .. PURPOS2 .aecTRIC TRANSiqSSJON mr. OlSTRibUUON .,· AREA. :AfF¢rto; A~ COl'iloJf!t.>tTEO ovdl PAfll::EL If··.,.- · .. ·, ... ,· IE~~ FEElf!U#t#-:~J. 't995. RECDADIHS Na. !;\'62ji304·7'l. ITEM 10·. RI6H1."TQ MAKf"tECE'!isARY Ms OA'~II.LS UPom·Ttre:LANO .:·,,, .. :: .. H!iflEIH:tJESCAIBaJ, AS ESTAiltI.;'iHE[l Uf·'vOLUME 31 Of ··-·.,.t0MMISS100ER' S 'Ali;!;.Ql;IBS; •• PAGE .• 4".15. :;· .•• ·., ·., ••• AREA .t.f'l:f;CTEO: PARCEL tJ:._. '. ,. _/i:-:,,,/.'>' ~ Dry co Su;;~yin'g': 'i~t.: ~:~/ll;blo},ff-~u~11 Ll'}AdJ. "''.~'.'.i~ 12714 VALLEY AVENUE EAST DWN. BY •. . .• --·-· . SUMNER. WA 98390 Ls. .. '.JJ.~~/200-t :.: 20030\':f 253-826-0300 fox 253-826__:9703 CHKO. BY SCAl.f -°!>JiEET ,t:' P.S. 1·-10cr . . !._ •• OF 2 ~ COUNTY, WASHINGTON B~~JbARY LINE ADJUSTMENT i)j • " ~ AREA co, A Sa,..ci,• F••i I OCD ' NEW I"'""·" I .... RECORDlNC NO. VOL/;·J.GE 2-) l "•lOO' SCALE: ~ "'l NO . .L,03L0013 ,;•" . ·,· .. B oBUiS.lll 57a6!f,! "' 0 ,00 ,oo Center )i~-~-licn :i:~rner SectiQ1f 14, Dicosed .:' l~.,1,';'.,n PiP.e'.with B~~s ·"Fm VISITED" July, ZQD4 HElD P!"f referel")~d survey_-:{~) ::· . · ,_, 1-liJ«l(M; {-•' r I___:__ -~ - I ··i l.r. ,. ~ .., PORTION Of •NOTE: 'II£ /fOfflJ\ UNE OF tel lOT D IS QI SUIIM5DI, P£R DEEU. ll1E NOIITII IJNE OF IOI LOT A I:! P"""'-'A ,om, _, 3a FEET SOl/nl DF 1111: ElQslNI YDoltlMDIT UN[ 8"w<tR \Wl)O ~ l£ a, 1<11rtlt ~ s£. NW 1/• ot __§§._ 1/•. s . .11... T. 23 w.. R.Q.E.,W.M. ~J., .. , ... I I DBRJffHURST I ··,....... I ... ,, .. ,,,_ I , I I I :0~ VOL 166 PAC-E 74 r Bross Ccip in f lldi.,, I • ~~', I 6 J0 :t;';,~ c. G Pl.at, I , I · Concrete Cose pe -. ••. .-:• , .. ,, m@ ~ F--.. -366'60 CJ.II Found" o, ._ ~60 I LOT 1 I LUI' 1:5 ROS 9508099008 ,:.; ·-im~i-w ~~; --<::.'":i:.° --:_:;,-1·" · l,.p. ---------____ -~~ I I I ~i!tV:i~dComer .···;. m;~~-_.---' w w ---._::i. -.----_J Sect1onl4 -):_ -· .;.:· _:t1:_~~..:..ilifim_!__~-+}{( !,~}~_lfll.~~--. 11111''0.l'V 12~A9' RaoortCapw-=--\,j~ J.outh'!!!sJ. l36th-street ~ T ~ --....J " · __ .. /,,~"·:::::~ .,>Jv~'~?~ ~ :=~-} ~ --.-~. ~~~ c: _J ·: t ~,.;_-'"f ~ ~~· -~ ~ +---~¥' • ...._.. .. . ...,4.?!' .-.-.,,' ~1: \ .f' ·=t-t I {rj .. . , ~~ ·' ·' 5111 "1!1'.Jlt: &§~· .·.' _.,. .~· '?'--~ • c. -§· --i:·. I r -----1 -I ·-146l,,QID41 I I J :~:1':."' , __ ,:-· = tlllllAf$ l'UIUO ·:.:.:.,,_."'.'" !fhr ~~ ~ ~'llollllfll' .... ..ino""-1'JJf1'E>mn1 :·\ .ts,_ . -- -~~::::::~ ,.. .-:·-T-~ : ,.,,'. I DPlalt ~l ,._ leJ:15 ~lli! Lot 2 KCSP 878133 8001!250639 -~ .. El~~" [I!::·· .. ,,, ... L.of: B . 1• """'°"'. ' .. ;r· -.. ,,, i ~, ~ I J.i:_Jil'_ I ~ .. =:. I ~i ,: ··... CEDAR P.4.j'K ~ I ~ / ....... ,.. ~ ii ~)~/~ __ .j_·'~~L~7~A1Ji~g :!3 1 1 • • O.ICE!B..E .:.' 1".· -'~,. J.'. ~ · "n E'v.~dell U) I .. 8..EVAJIUN •68.B7 I,, l . := 7 PJ/(}J'osE. ,j/paf ,:.; Jl1 : .: 1 Lfu 2 ;:::;u~W:.:1:vn cotnRCJ. POrNr ME.NT;: 1 1 :' LOIPilOi'ii ,./ II) t:·'· EQUlPWEITT USED - .•. _,;_, .aAs1s OF ~ , , •• • •. :. ------1 JI • ~ I_ . .-·1 l~ON GTS 38 TOHL STATION ~ '··f .-· Wl. s SUAVE;--.' IS -BASED ON ... Plllc---VIIJUS SUR't'EY Of' ' ,ur Wt Ill-~" US! '""' "'111' -,~.., IJl:!o: HP-.esx cu TA CDLL.ECTOfl a:, mrn P!loPERn,.'.AEcoAO or SUfWJ;V. 11FN ~o8099008. 0 i<m1r : "'""''""' ~1: .,,,11'(,,:r '"""1,ll IF <Etr.r;:, " ·., -~· I I (1) t<l~_!(OCINTY."/'ilASHIN!ll~tl•'' \ _.:,: "1ti'l:6 !rtil : "I:! l f'ROC[OUR( US[O ..q I g .. -.,· .:' :. ;: ·. :.... .c FIELD TRAVER.SE I: ELECTAONrc DA1A CCll.U:CTION -•~, ...... -·a,..s1s Of BORING :( • .'··· .-/ .,,,•' 1·12 J<lli-~~-, .J I j 1-EETS OR EXCEEDS 3~2-1:.10-000 ,i ~ 8 MONUHENT!f:THE.~ESl;LIN£ CFc:rltE SOUTl-l!lAST_i;IUAIITE.A \ /7.!'~r.o. ~ v-. I Ci}~ ~ ~HI !1508099008. AOU'ffD"---ll;JB'-19.,s·· .:·· ,, ... , :_-. ·, ao _._..,,, f ~ 0 ,jli Of SECTIOl'I U AS "Stl()IIN {»-1 AECORI? ~ ~fEY. .• : F....i .._, I I I~ t® <> ._.. .-.-•• -~-·· -,:... -~---'"'--.. ~E~-... I ,;uJ:,~ REHREt.CE-~ll,wps _ •• ,.-·· :.·:"· .. ·.•• 1 :-.--,,.-{/ ""-·~·-,.-:s.;:-:=---;:=.:.::..t,._t-~7--.-_1:.:r--~ ~:.,~~~~~ICATED ::, ol <i:> PLAT Of cAliOl...wocd."JA1--7961i21105a5 ·: •. I ,7 . . -,. 1 • SET REBAR i.: CJ.P Ls, 62...."B/3~us q ., I" Pl.U Of ROSf G4RlEIIS. AfH 6?fi!Ol4 :. . ''· . lot 7 / .:· 4 8aoE.e,j w; I I •j FIR!:: HYDRANT ;;, ' (1) -;;; l< Pl.AT IF WILLll>l"S SONIY 51..0PES. AFR 55979&,-•.,r; J_•,•·:. ;: ~ > ,g Z ~COFll Of SIJRVET • .lFN 7Btl0'390U :... 1-<.pse .. / t_oo; / ~ rc"d ~¢6, ; I ~ ::~ ':-~A ~, -q:: I~ RECOFO OF SUHYEY. MN 9~eo99008 {lll ......... ,. -,,,,f'w9J(l.ixul f" ;: I ;J' I I Sur ,fl El.ECTRIC MOEH i:J ,...· <:>J •• ,,,,,~_, •• •V Si¥f~9"£"ii:!3'S• \• 1.(;J!nCO!li 0 PHONI:: OR CMI.£ PWEST.<L ~ :;:J I'.;; ---\ ~-;K-..x-,.-x, ~-><-if.~~ 1,. I 'tr CAS lolETER lLJI -a ~ SE t38Ui Place 1---1 .,. --l...4'H""......., •• ~:-.:;:·-~:i.~g!O""'Jill-....c;;;--ii I -=-~S~f~KcEORwlREFENcE ~, L.Q ----·;. ·."F•oce 8am • • 4-:;;.,., Wir~ IS f:llll~ -..=----..!j-IUTEFLli'IE ~, '"""I ~ ') _ / , · >.. . .} fncroqctieo • Fence f......t • J ""'7T77T> IIUILDINGS 2 I f\l 1 • L<ar·!I 1 foot· .: ., • ._ (M) MEASI.JRO) l:! !~ Gardens ' ' · ···-· ,.· ·' ,, , . .1 , , 1¥nl ,:;m ·'PROP . ·· . '•·-~ r ~ VOL 8:J PAGE 69[ Loi 10 I :· .:· . q!/Efl P.4-.r I J !.QT 3 . ' "\. Nicbnls Place .. · "5' Brass Cap m · I '-----~ J .W3POOJ-5 ·· •. .l.,. Concrete Ccse per+ ~--________________________ s~ _ _1__±_4t9 ~t:;;ti .( .. /./ ,/ f:}'. ,/. .,,> g;f;f:,:: .. ., ,. Sovtf 1/4 Corner CONC MON W/COPPER PLUG -------.-.• ~;,~25f7)2."-,,5WiF01~ ;, -:·/--7 • .-.• ~ --~ --· Section 14 VISITED Melrch, 1999 ·· .,. 253-626-0300 fox 253-626-9703 Mair/Nybloq_r']ounur§ Lfiit Adjushn,;it :· y :· __ ,· .;l-'·.,._,{ CHKO. f!( P.S. sou: 1°-H)O' -:f 200JO 12 K ~·~-i OF_../-2 08/18/2004 12:29 2535390514 AFTER RECORDING MAIL TO: Name Address City/State SBI Developing LLC PO Box 73790 Puyallup, WA 98373 Document Title(s) (for tran,actions contaned therein): SOUNDBUILT HOMES PAGE 02 ·-1. Temporary Construction Easement - Reference Number(s)·of Documents Assigned or released: Grantor(s): (ta,t nome first, then first name and mlddle lnltial) 1. Mair,.Robert 2. Mair, Oyderae [ ] Additional information on page of document Grantee(s): (Last name ftrst, then first name and middle ;nitia!J· L SBI Developing LLC, 2. . '· '!'•i ' :· li""RICAN L "t 0, ::\:) i nNIC ( 1--l Si.e.. I ( J Additional information on page of document Abbreviated Legal Description as follows: (I.e. lot/block/plat or sealon/toWMhip/range/quan,,r/quaiterJ Ptn of N 1/2 N 1/2 NW 1/4 NW 1/4 SE 1/4 Sec. 14 Twn 23 N R 5 E Assessor's Property Tax Paroel/ Account Number(s): 142305902207 [ X Complete legal description Is on page 4 and 5 of document ( ] I am requesting an emergency nonstandard recording tor an additional fee as provided in RCN 36.18.010, I understand the recording, processing requirements may cover up or otherwise obscure some part of the text of the original document. ote: 77,e AurJHr;r(Rer:on:fer will rely on /fie lnforrnabiii,'prov/deti on the fotm. aCCIJfl)cy or completeness of the indexing /nform,;uon provlrfed herein. Tile st,,ff will not read the document ID verify rM ] ---------·----------···-------· ·---·--1 ·J., ' -- - }o - 08/18/2004 12:29 2535390514 SOUNDBUILT HOMES PAGE 03 After recording return to: TEMPORARY CONSTRUCTION EASEMENT Reference#: NIA Granter: ROBERT MAIR and CL YDERA.E MAIR Grantee: SBI DEVELOPING, LLC t.egal Description: PTN ofNl/2 NI/2 NW l/4 NW V. SEl/4 SEC. 14 TWN 23 NR S £ Additio!lal Legal Description: Attachments l and 2 Assessor's Tax parcel ID#: 142305-9022-07 The Grantors, as named above, for and in consideration of mutual benefits, do hereby grant, bargain, sell, convey and warrant to the above named Grantee, its successors and assigns, a non-exclusive temporary construction easement for jlurposes of constructing, reconstructing, installing, enlarging, operating, maintaining, repairing and replacing an underground stonn drainage pipe and associated appurtenances over, under, through, across and upon the following described property in King County, Washington: That certain perfectly square area of land, in the southeastern most comer of the property described in Exhibit A ["Parcel A"], that has, as two of its sides, forty (40) feet along the south boundary line from the southeast comer of Parcel A and forty (40) feet along the east boundllr)' line from the southeast corner of Parcel A ["Temporary Easement Area"]. For the purpose of constructing, reconstructing, installing, repairing, replacing, enlarging, operating and maintaining.an underground storm drainage pipe and associated appurtenances, together with the right of ingress and egress thereto as required and approved by King County, for the purpose of providing drainage service to the property described in Exhibit B ["Property"). This easement is granted subject to the following tenns and conditions: I. Grantee agrees to use reasonable care not to damage any structures or utilities on Parcel A and agrees to immediately repair the same at Grantee's cost and expense if Grantee, or Grantee's agents damage Parcel A structures or utilities. Grantee further agrees to use reasonable care not to damage the landscaping on Parcel A or the T emporaty Easement Area and to return said landscaping to at least as good a condition as it was in on the date of this Amendment, prior to expiration of this Easement. ·;"I<, I .,....__ - 08/18/2004 12:29 2535390514 SOUNDBUILT HOMES PAGE 04 Construction Easement 2 2. Grantee further agrees to indemnify and defend Seller for any claims resulting from the acts or omissions of Grantee or GraTJtee's agents upon Parcel A. 3. This Temporary Construction Easement shall expire upon the date Grantee's construction of the storm system and related appurtenances is complete and Granter has signed a non-exclusive pennanent easement withi.n the Temporary Easement Area as are required by King County with respect to the actually constructed stonn water system and appurt.enances described above. Grantee agrees to use its best efforts to have such permanent easement area not exceed the south 18 feet of the east 25' feet of Parcel A, and to minimize any above ground appurtenances on Parcel A. Notwithstanding the foregoing, Granter shall .not be obligated to execute any permanent easement which so far exceeds the south 18 feet of the east 25 feet of Parcel A as to, (i) interfere with any structures or improvements located on Parcel A as of the date on which the easement is requested, or (ii) to materially diminish the fair market value of Parcel A This easement shall run with the Property, and shall be binding upon the parties, their heirs, successo.rs in ~~~ . -~. ,~ IN WITNESS WHEREOF, the Granter has caused this instrument to be executed thi,,JJ, day of July, 2004. C&Mt1:~;/~ ' Nla..,(,/), Robert Mair - - 08/18/2004 12:29 2535390514 SOUNDBUILT HOMES PAGE 05 Construction Easement 3 COUNTY OF ~Qv"C,Q. ) . ) ss STATEOFWASHlNGTON J . On this day ofJ:JJ · day o • ~ before me, the undersigned, a Notary Public; in and for the State of Was · , duly commissioned and sworn, personally appeared ROBERT and CL YDERAE MAIR, to me known to be the individuals described in, and who executed the within and foregoing instrument, and acknowledged that they signed the same as their free and voluntary act and deed for the uses and purposes therein mentioned. WITNESS my hand and official seal hereto affixed the day and year first above written. OT ARY PUBLTC in~ the State of Washington, residing ~~ .-::::: My Commission Expiresc= ?:Zs. - - - 08/18/2004 12:29 2535390514 Construction Easement SOUNDBUILT HOMES EXHIBIT A PARCEL A PAGE 06 4 . THE WESTERLY 199 FEET OF THAT PORTION OF THE NORTH HALF OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGES EAST, W.M., LYING EASTERLY OF THE EASTERLY MARGIN OF 156TH A VENUE S.E. AS DEEDED TO KJING COUNTY BY DEED RECORDED UNDER RECORDJNG NUMBER 1094243; TOGETHER WITH A NON-EXCLUSIVE EASEMENT FOR INGRESS, EGRESS AND UTILffiES OVER, UNDER AND ACROSS THE NORTH 15 FEET OF THE WEST 187 FEET (AS MEASURED FR.OM THE EASTERLY MARGIN OF SAID 156rn AVENUE S.E.) OF LOT 20F SHORT PLAT NO 878133, RECORDED UNDER I<ING COUNTY RECORDING NO. 8002250639, IN THE RECORDS OF KING COUNTY, W ASH!NGTON. SITUATE IN COUNTY OF KING, STATE OF WASHINGTON. ,J,, ' -- - 08/18/2004 12:29 2535390514 Construction Easement SOUNDBUILT HOMES EXHIBITB PROPERTY PAGE 07 5 THE EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHWEST QUARTER OF SECTION 14, TOWNSIDP 23 NORTH, RANGE 5 EAST, WILLAMETTE MERIDIAN, IN KING COUNTY, WASHINGTON; EXCEPT THAT PORTION OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SAID SECTION 14 DESCRIBED AS FOLLOWS: . BEGINNING AT THE SOUTHEAST CORNER OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER AS THE POINT OF TRUE BEGINNTNG; THBNCE NORTH 25 DEGREES 21 MINUTES EAST 523.99 FEET ALONG THE EAST LINE OF SATO EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER; THENCE NORTH 88 .DEGREES 7 MINUTES 58 SECONDS WEST 653.61 FEET TO THE WEST LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER; THENCE SOUTH 0 DEGREES 27 MINUTES 5 SECONDS WEST 525.82 FEET TO TliE SOUTH LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER. OF THE SOUTHEAST QUARTER; THENCE SOUTH 88 DEGREES 17 MINUTES 35 SECONDS EAST 653.84 FEET ALONG THE SOUTH LINE OF SAID EAST HALF OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER TO THE TRUE POINT OF BEGJNNTNG; AND EXCEPT COUN"fY ROADS, THAT PORTION OF THE NORTH HALF OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE NORTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSIDP 23 NORTH, RANGE S EAST, W.M., LYING EASTERLY OF THE EASTERLY MARGIN OF 1 S6rn A VENUE S.E. AS DEEDED TO KIING COUNTY BY DEED RECORDED UNDER RECORDING NUMBER I 094243; EXCEPT THE WESTERLY 199 FEET THEREOF, AS MEASURED FROM Tira EASTERLY MARGTNOF SATO 156TH AVENUE S.E., LYlNG SOUTHERLY OF THENORTH30 FEET THEREOF; TOGETHER WITH A NON-EXCLUSIVE EASEMENT FOR INGRESS, EGRESS AND UTILITIES OVER, UNDER AND ACROSS THE NORTH I 5 FEE; OF THE WEST 187 FEET (AS MEASURED FROM THE EASTERLY .MARGIN OF SAID 156TH A VENUE S.E.) OF LOT 2 OF SHORT PLAT NO 878133, RECORDED UNDER KING COUNTY RECORDING NO. 8002250639, RECORDS OF KING COUNTY, WASINGTON. ALSO TOGETHER WITH A NON-EXCLUSIVE EASEMENT FOR INGRESS, EGRESS AND IJfILITIES OVER, UNDER AND ACROSS THE SOUTH IS FEE OF THE EAST 22 FEET OF THE WEST 199 FEET, AS MEASURED FROM THE EASTERLY MARGIN OF SAID 156m A VENUEN S.E., OF THAT PORTION OF THE NORTH HALF OF THE NORTH HALF OF THE NORTHWEST QUARTER OF THE NORTHWEST QUARTER OF THE SOtrl'HEAST QUARTER OF SECTION 14, - 08/18/2004 12:29 2535390514 50UNDBUILT HOMES PAGE 08 Construction Easement 6 TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., LYING EASTER!. Y OF THE EASTERLY MARGiN OF SAID l 56TH A VENUE S.E. IN KING COUNTY, WASHINGTON. ~ CORE ~DESIGN !RECEIVED NOV 1 7 2004 KING COUNTY LAND USE SERVICES Core Design, Inc. 14711 N.E. 29th Place Suile #101 Bellevue, Washingfon 98007 425.885.7877 Fax 425.885.7963 TECHNICAL INFORMATION REPORT (T.I.R.) FOR EVENDELL KING COUNTY, WASHINGTON Prepared by: David E. Cayton, P.E. Date: November 8, 2004 Core No.: 04009 l O!'IRE.,6-12-t,? ,<· . . .LIi • (0-()~ . ENGINEERING PLANNING . SURVEYING ' I ( ) ( EASTBASJN The basin boundary delineated for the East Basin includes the development, SE 1361h Street east of the existing basin ridge, and a portion of 160th A venue SE. A portion of the shoulder additional along 1601h Avenue SE will not be included in the existing condition, i.e. not captured in the proposed drainage system, since an equal amount of existing asphalt will be included within the existing/developed East Basin and treated as pasture in the existing co_ndition. For the reasons stated above, detention does not need to account for the bypass area since existing asphalt will be treated in the place of the bypass impervious surfaces. The eastern portion of the site is 10.06 acres. The existing coverage is a combination of impervious surfaces associated with the existing residence, pasture, landscaping, lawn, and forest. The existing landscaping and lawn will be considered pasture per Table 3.2.2.C in the 1998 KCSWDM for existing developed areas with densities less than 4 DU/AC. The site is covered with 3.00 acres of pasture and 6.62 acres of forest. Existing impervious surfaces from the existing residence and outbuildings cover a total area of 0.44 acre. Per Table 3.2.2.E in the 1998 KCSWDM, the effective impervious fraction for the site is 0.40 for existing rural areas. The effective impervious area is therefore 0.40*0.44 acre= 0.18 acre. Pasture will be utilized for the non-effective impervious surfaces (0.44 acre-0.18 acre= 0.26 acre). The following information was used for generating time series and flow frequencies. EAST BASIN Total Area= 10.06 acres EXISTING CONDITIONS (exeast) GROUND COVER AREA(acre) Till-Forest 6.62 Till-Pasture (3.00 + 0.26) 3.26 Impervious 0.18 ( ; TRIBUTARY AREA CONDITIONS EAST BASIN The East Basin receives 0.36 acre of upstream drainage from forest area just west of the site. The following information was used for generating time series and flow frequencies. EAST UPSTREAM Total Area= 0.36 acre TRIBUTARY CONDITIONS (upsteast) GROUND COVER AREA(acre) Till-Forest 0.36 . . , ( f ) • I ; Flow Frequency Analysis Time Series File:exwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.128 2 2/09/01 18:00 0. 049 7 1/05/02 16:00 0.116 3 2/28/03 3:00 0.014 8 3/24/04 19:00 0.066 6 1/05/05 8:00 0.109 4 1/18/06 16:00 0.105 5 11/24/ 06 4:00 0. 216 1 1/09/08 6:00 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.216 1 100.00 0.990 0.128 2 25.00 0.960 0.116 3 10.00 0.900 0.109 4 5.00 0.800 0.105 5 3.00 0.667 0.066 6 2.00 0.500 0.049 7 1. 30 0.231 0. 014 8 1.10 0.091 0.187 50.00 0.980 Flow Frequency Analysis ) Time Series File:preeast.tsf L Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.698 2 2/09/01 18:00 0.999 1 100.00 0.990 0.238 7 1/05/02 16:00 0.698 2 25.00 0.960 0.580 3 2/28/03 3:00 0.580 3 10.00 0.900 0.060 8 8/26/04 2:00 0.559 4 5.00 0.800 0. 339 6 1/05/05 8:00 0.516 5 3.00 0.667 0.559 4 1/18/06 20:00 0.339 6 2.00 0.500 0.516 5 11/24/06 4:00 0.238 7 1. 30 0.231 0.999 1 1/09/08 9:00 0.060 8 1.10 0. 091 Computed Peaks 0.899 50.00 0.980 ( ( ---, Flow Frequency Analysis ) Time Series File:posteast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 94 6 2/09/01 2:00 3.90 1 100.00 0.990 1. 59 8 1/05/02 16:00 2.52 2 25.00 0.960 2.32 3 2/27/03 7:00 2.32 3 10.00 0.900 1. 73 7 8/26/04 2:00 2.08 4 5.00 0.800 2.08 4 10/28/04 16:00 2.06 5 3.00 0.667 2.06 5 1/18/06 16:00 1. 94 6 2.00 0.500 2.52 2 10/26/06 0:00 1. 73 7 1. 30 0.231 3.90 1 1/09/08 6:00 1. 59 8 1.10 0.091 Computed Peaks 3.44 50.00 0.980 ( ) { Flow Frequency Analysis ··, Time Series File:exeast.tsf ) Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.675 2 2/09/01 18:00 0.970 1 100.00 0.990 0.232 7 1/05/02 16:00 0.675 2 25.00 0. 960 0.564 3 2/28/03 3:00 0.564 3 10.00 0.900 0.060 8 8/26/04 2:00 0.541 4 5.00 0.800 0.329 6 1/05/05 8:00 0. 501 5 3.00 0.667 0.541 4 1/18/06 20:00 0. 329 6 2.00 0.500 0.501 5 11/24/06 4:00 0.232 7 1. 30 0.231 0.970 1 1/09/08 9:00 0.060 8 1.10 0.091 Computed Peaks 0. 872 50.00 0.980 ( ) ( ( ; f Flow Frequency Analysis Time Series File:upsteast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.023 2 2/09/01 18:00 0.006 7 1/06/02 4:00 0.017 4 2/28/03 3:00 0.001 8 3/24/04 20:00 0.010 6 1/05/05 8:00 0.018 3 1/18/06 20:00 0.015 5 11/24/ 06 6:00 0.029 1 1/09/08 9:00 Computed Peaks -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.029 1 100.00 0.990 0.023 2 25.00 0. 960 0.018 3 10.00 0.900 0.017 4 5.00 0.800 0.015 5 3.00 0.667 0.010 6 2.00 0.500 0.006 7 1. 30 0.231 0.001 8 1.10 0.091 0.027 50.00 0.980 ( { DEVELOPED CONDITIONS The developed basin ridge delineated and allowed per SWM Adjustment L02V0024 was regraded at a different location than what currently exists. See Existing and Developed Conditions Exhibit on the following pages. The relocation was logical based on the property boundary and basin ridge relationship. A small triangle of area adjacent to the existing basin ridge within the existing West Basin is currently located at the most southwestern end of the property. This triangle of area is approximately 300' from the West Basin located within the property boundary, therefore this small area will be conveyed to the East Basin in the developed condition and an equal amount of area within the existing East Basin located along adjacent to the basin ridge at the north end of the site will be conveyed to the West Basin. Since an adjustment was required to relocate the basin ridge, an automatic 10% safety factor was added to the detention calculations. The maximum impervious area per lot was calculated using the criteria in the 1998 King County Surface Water Design Manual page 3-27 and K.C.C.21A.12.030. The proposed development is urban residential. The site is R-6 zoning. The maximum impervious area per lot is 70%. WEST BASIN The lots within the West Basin cover a total area of 1.15 acres. Maximum Lot Impervious Area= 70%*1.15 acres= 0.81 acre West Basin Impervious Area Delineation Onsite road and sidewalk 0.49 acres Imoervious area oflots 0.81 acres Total imoervious area 1.30 acres The input used for the KCRTS analysis is summarized in the table below: WEST BASIN Total Area= 1.81 acres DEVELOPED CONDITIONS (devwest) GROUND COVER AREA(acre) Till-Grass (Landscaoin") 0.51 Impervious 1.30 21A.12.030 A. Densities and dimensions· residential zones . RESIDENTIAL z AURAL ...... ...... 0 N IIESEIM ... IDENTW. • • ' STANOAJmS RA-2.S ..... RA-10 ..... UR .. , 1M ~ ... .... .... ..... ...... 1171 Bao Donslty: G.2 G.2 0:1 .... ... 1 • • I 12 " .. .. ------..... ..... ..... -..... -..... --1211 (I) MSl . Hmdmum Dcn:sJty: OA OA • • 12 " 'Z1 ,. 72 o.o&Ung UnWAcro --..... ----·-...... Ml 121>1 (211) 1221 --..,. .... ...,. -75% -.... (2) (12) M21 (12) 01) {18} 01) (11) (11) (11) (11} (23) ( -Lot 120ft 135ft 135ft ·1Uft '5ft '6ft 30ft 30ft 30ft ,.. 30ft ,Oft 30ft -{7) m (9) --30ft "ft 30ft 30ft "'ft 20ft 10ft 10ft 10ft 10 ft 10ft 10R 10ft -(I) (9) ISi ISi m m (I) (I) .1'1 (I) (I) (I) (I) (3) ---9ft 10ft 10ft 10ft • ft 1ft 5ft Oft Sft 5ft Oft 'ft • ft -(I) (I) (I) (I) m m (1D) MO) 00) (1D) (3) 01) B&aoHolght 40ft ... 40ft ... ,,. 39ft "5ft ,. ft ,,. 00ft ... 80ft 00ft 14! "'5ft 49ft IGft ... 00ft 041 041 (141 (14) 041 I """""•m \ --"" 12.5% "" "" --75% ..,. ..,. ..,. -I -N-011 (11) 01) (11) (11) M<l I,.._...., -/ 01) (11) 01) (1t) \. -(II} ( 12·2 (King County 6-00) ) Flow Frequency Analysis Time Series File:devwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.361 6 2/09/01 2:00 0. 722 1 100.00 0.990 0.301 8 1/05/02 16:00 0.485 2 25.00 0.960 0.432 3 2/27/03 7:00 0.432 3 10.00 0.900 0.333 7 8/26/04 2:00 0. 399 4 5.00 0.800 0.399 4 · 10/28/04 16:00 0.384 5 3.00 0.667 0.384 5 1/18/06 16:00 0. 361 6 2.00 0.500 0.485 2 10/26/06 0:00 0.333 7 1. 30 0.231 0. 722 1 1/09/08 6:00 0.301 8 1.10 0. 091 Computed Peaks 0.643 so.co 0.980 ( ' ) ( ( ) ( EAST BASIN The lots within the East Basin cover a total area of 6.62 acres. Maximwn Lot Impervious Area= 70%*6.62 acres= 4.63 acres East Basin Imoervious Area Delineation Onsite road and sidewalk 2.06 acres Impervious area oflots · 4.63 acres Total imoervious area 6.69 acres The input used for the KCRTS analysis is summarized in the table below: . EAST BASIN Total Area= 10.06 acres DEVELOPED CONDITIONS (deveast) GROUND COVER AREA(acre) Till-Grass (Landscapin!!) 3.37 Imoervious 6.69 ' Flow Frequency Analysis I Time Series File:deveast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 1. 92 6 2/09/01 2:00 3.88 1 100.00 0.990 1. 58 8 1/05/02 16:00 2.52 2 25.00 0. 960 2.31 3 2/27/03 7:00 2.31 3 10.00 0.900 1. 73 7 8/26/04 2:00 2.08 4 5.00 0.800 2.08 4 10/28/04 16:00 2.05 5 3.00 0.667 2.05 5 1/18/06 16:00 1. 92 6 2.00 0.500 2.52 2 10/26/06 0:00 1. 73 7 1. 30 0.231 3.88 1 1/09/08 6:00 1. 58 8 1.10 0.091 Computed Peaks 3.42 50.00 0.980 ( ( ) ( { B. Detention Routing Calculations Per the Hearing Examiner's Conditions, the West Basin wetvault will mitigate for increased drainage flows from the developed West Basin utilizing Level 3 Flow Control. The East Basin wetpond will mitigate for increased drainage flows from the developed East Basin utilizing Level 2 Flow Control. All stormwater mitigation facilities will be designed according to the 1998 KCSWDM. Since an adjustment was required to relocate the basin ridge, an automatic 10% safety factor was added to the detention calculations. WEST BASIN The West Basin will utilize a wetvault to accommodate the required Level 3 Flow Control.· The West Basin wetvault (wvault.rdf) was sized based on the 1998 KCSWDM and KCRTS Computer Software Reference Manual. See attached KCRTS printouts. The wetvault per KCRTS will have a surface area of2,967 square feet and a depth of7.42 feet. To accommodate the required I 0% safety factor, the vault will be constructed with a surface area of 3,264 square feet (34 feet by 96 feet). West Basin Wetvault Overflow Elevation The primary overflow for the vault is the riser pipe within the control structure. The water surface elevation above the riser for the 100 year developed flow is calculated assuming all orifices are plugged. To pass the 100-year return period storm, 0.72 cfs, through a 12" overflow riser will require 0.47 feet of head (From Figure 5.3.4.H in the 1998 KCSWDM: Qweir = 9.739DH312 => 0.72 = 9.739(12/12)H312 => H = 0.18 feet). The primary overflow elevation would therefore, be equal to the elevation of the top of the riser plus the amount of head required to pass the 100-year return period storm, Elev. 478.47 + 0.18 feet= Elev. 478.65. The ceiling of the vault is located at elevation 459.0 and will accommodate the required overflow elevation. ,,.~--..._ , Retention/Detention Facility l.u\/f\L)LT. I)O(,, Type of Facility: Detention Vault Facility Length: 87.27 ft Facility Width: 34.00 ft Facility Area: 2967. sq. ft Effective Storage Depth: 7.42 ft Stage 0 Elevation: 4 71. 08 ft Storage Volume: 22016. cu. ft Riser Head: 7_39· ft Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 o.oo 0.81 0.048 2 3.60 1. 20 0.076 4.0 3 5.20 a.so 0.010 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs). (cfs) o.oo 471.08 89. 0.002 0.000 0.00 ( 0.01 471.09 119. 0.003 0.002 0.00 0.02 471.10 148. 0.003 0.002 0.00 0.03 4 71.11 178. 0.004 0.003 0.00 0.04 471.12 208. 0.005 0.004 0.00 0.05 471.13 237. 0.005 0.004 0.00 0.06 471.14 267. 0.006 0.004 0.00 0.07 471.15 297. 0.007 0.005 0.00 0. 21 471.29 712. 0.016 0.008 0.00 0.36 471. 44 1157. 0.027 0. 011 0.00 0.50 471. 58 1573. 0.036 0.013 0.00 0.65 471.73 2018. 0.046 0. 014 0.00 0.79 471.87 2433. 0.056 0.016 0.00 0.94 472.02 2878. 0.066 0.017 0.00 1. 08 472.16 3294. 0.076 0.019 0.00 1. 23 472.31 3739. 0.086 0.020 0.00 1. 37 472.45 4154. 0.095 0.021 0.00 1.52 472.60 4599. 0.106 0.022 0.00 1. 66 472.74 5015. 0 .115 0.023 0.00 1.81 472.89 5460. 0.125 0.024 0.00 1. 95 473.03 5875. 0 .135 0.025 0.00 2.10 473.18 6320. 0.145 0.026 0.00 2.24 473.32 6736. 0.155 0.027 0.00 2.39 473.47 7181. 0.165 0.027 0.00 2.53 473.61 7596. 0.174 0.028 0.00 2.68 473.76 8041. 0.185 0.029 0.00 2.82 473.90 8457. 0.194 0.030 0.00 2.97 474.05 8902. 0. 204 0.031 0.00 ( 3.11 474.19 9317. 0.214 0.031 0.00 3.26 474.34 9762. 0.224 0.032 0.00 3.40 474.48 10177. 0.234 0.033 0.00 3.55 474.63 10623. 0.244 0.034 0.00 . 3. 60 474.68 10771. 0.247 0.034 0.00 3.61 474.69 10801. 0.248 0.034 0.00 3.63 474. 71 10860. 0. 249 0.035 0.00 3.64 474. 72 10890. 0.250 0.037 0.00 3.65 474.73 10919. 0.251 0.039 0.00 3.66 474.74 10949. 0.251 0.041 0.00 3.68 474.76 11008. 0.253 0.045 0.00 3.69 474.77 1103 8. 0.253 0.046 0.00 3.70 474.78 11068. 0.254 0.047 0.00 3.84 474.92 11483. 0.264 0.054 0.00 3.99 475.07 11928. 0.274 0.060 0.00 4.13 475.21 12343. 0.283 0.065 o.oo 4.28 475.36 12789. 0.294 0.069 0.00 4.42 475.50 13204. 0.303 0.073 0.00 4.57 475.65 13649. 0.313 0.076 o.oo 4.71 475.79 14064. 0.323 0.080 0.00 4.86 475.94 14510. 0.333 0.083 0.00 5.00 476.08 14925. 0.343 0.086 0.00 5.15 476.23 15370. 0.353 0.089 0.00 5.20 476.28 15518. 0.356 0.090 o.oo 5.21 476.29 15548. 0.357 0.090 0.00 5.22 476.30 15578. 0.358 0.091 0.00 5.23 476.31 15607. 0.358 0. 092 0.00 5.24 476.32 15637. 0.359 o. 092 0.00 5.39 476.47 16082. 0.369 0.096 0.00 5.53 476.61 16498. 0.379 0.100 0.00 / 5.68 476.76 16943. 0.389 0.103 0.00 ( 5.82 476.90 17358. 0.398 0.106 0.00 5.97 477.05 17803. 0.409 0.109 0.00 6 .11 477.19 18218. 0 .418 0.112 0.00 6.26 477.34 18664. 0.428 0 .115 0.00 6.40 477.48 19079. 0. 438 0 .118 0.00 6.55 477.63 19524. 0.448 0.120 0.00 6.69 477.77 19939. 0.458 0.123 0.00 6.84 477. 92 20385. 0.468 0.125 0.00 6.98 478.06 20800. 0.478 0.128 0.00 7.13 478.21 21245. 0.488 0.130 0.00 7.27 478. 35 21660. 0.497 0 .133 0.00 7. 39 478.47 22016. 0.505 0.134 0.00 7.49 478.57 22313. 0.512 0.444 0.00 7.59 478.67 22610. 0.519 1. 010 0.00 7.69 478.77 22907. 0.526 1. 740 0.00 7.79 478. 87 23203. 0.533 2.530 0.00 7.89 478.97 23500. 0.539 2.820 0.00 7.99 479.07 23797. 0. 546 3.070 0.00 8.09 479.17 24094. 0.553 3.310 0.00 8.19 479.27 24390. 0.560 3.530 0.00 8.29 479.37 24687. 0.567 3.740 0.00 8. 39 479.47 24984. 0.574 3.930 0.00 8. 49 479.57 25280. 0.580 4.120 0.00 8.59 479.67 25577. 0.587 4.290 0.00 8.69 479.77 25874. 0.594 4.470 0.00 8.79 479.87 26171. 0.601 4.630 0.00 ( 8.89 479.97 26467. 0.608 4.790 0.00 8.99 480.07 26764. 0.614 4.940 0.00 9.09 480.17 27061. 0.621 5.090 0.00 • . l ( ( 9.19 480.27 27357. 0.628 9.29 480.37 27654. 0.635 Hyd Inflow Outflow Peak Target Cale Stage Elev 1 0. 72 0.22 0.22 7.42 478.50 2 0.36 ******* 0.12 6.54 477.62 3 0.37 ******* 0 .11 5.87 476.95 4 0.38 ******* 0.09 5.07 476.15 5 0.43 ******* 0.09 5.01 476.09 6 0.23 ******* 0.06 3.91 474.99 7 0.30 ******* 0.03 3.29 474.37 8 0.33 ******* 0.03 2.75 473.83 ---------------------------------- Route Time Series through Facility Inflow Time Series File:devwest.tsf Outflow Time Series File:wout Inflow/Outflow Analysis Peak InflOw Discharge: 0.722 CFS at Peak Outflow Discharge: 0.222 CFS at Peak Reservoir Stage: 7.42 Ft Peak Reservoir Elev: 478.50 Ft Peak Reservoir Storage: 22102. Cu-Ft 0.507 Flow Frequency Analysis Time Series File:wout'.tsf Project Location:Sea-Tac Ac-Ft 5.230 0.00 5.370 0.00 Storage (Cu-Ft) (Ac-Ft) 22102. 0.507 19496. 0.448 17498. 0.402 15128. 0.347 14956. 0.343 11683. 0.268 9839. 0.226 8260. 0.190 6:00 on Jan 9 in Year 8 11:00 on Jan 9 in Year 8 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Return Prob (CFS) (CFS) (ft) Period 0.120 2 2/09/01 20:00 0.222 7.42 1 100.00 0.990 0.032 7 12/28/01 18:00 0.120 6.54 2 25.00 0. 960 0.086 5 3/06/03 22:00 0.107 5.87 3 10.00 0.900 0.030 ·0 8/26/04 7:00 0.087 5.07 4 5.00 0.800 0.057 6 1/05/05 15:00 0.086 5.01 5 3.00 0.667 0.087 4 1/18/06 23:00 0.057 3.91 6 2.00 0.500 0.107 3 11/24/06 7_: 00 0.032 3.29 7 1. 30 0.231 0.222 1 1/09/08 11: 00 0. 030 2.77 8 1.10 0.091 Computed Peaks 0.188 7.41 50.00 0.980 Flow Duration from Time Series File:wout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.002 34644 56.497 56.497 43.503 0.435E+OO 0.005 4824 7.867 64.364 35.636 0.356E+OO 0.008 5399 8.805 73.169 26.831 0.268E+OO 0.012 3897 6.355 79.524 20.476 0.205E+OO 0.015 4088 6.667 86.190 13.810 0.138E+OO 0.018 2706 4. 413 90.603 9.397 0.940E-01 0.022 2069 3.374 93.977 6.023 0.602E-01 0.025 1286 2.097 96.075 3. 925 0. 393E-01 0.028 1042 1. 699 97.774 2.226 0.223E-01 0.032 703 1.146 98.920 1.080 0.108E-01 -·" ! ( 0.035 0.039 0.042 0.045 0.049 0.052 0.055 0.059 0.062 0.065 0.069 0.072 0.075 0.079 0.082 0.085 0.089 0.092 0.095 0.099 0.102 0.105 0.109 0.112 0.116 0.119 327 7 11 12 32 35 31 20 13 12 16 16 18 18 19 10 17 5 10 3 7 5 6 2 3 4 0.533 0. 011 0.018 0.020 0.052 0.057 0.051 0.033 0.021 0.020 0.026 0.026 0.029 0.029 0.031 0.016 0.028 0.008 0.016 0.005 0. 011 0.008 0.010 0.003 0.005 0.007 Duration Comparison Anaylsis Base File: exwest.tsf New File: wout.tsf 99.454 99.465 99.483 99.503 99.555 99.612 99.662 99.695 99. 716 99.736 99.762 99.788 99.817 99.847 99.878 99.894 99.922 99.930 99. 946 99.951 99.962 99. 971 99.980 99.984 99.989 99.995 Cutoff Units: Discharge in CFS 0.546 0.535 0.517 0. 497 0.445 0.388 0.338 0.305 0.284 0.264 0.238 0. 212 0.183 0.153 0.122 0.106 0.078 0.070 0.054 0.049 0.038 0. 029 0.020 0.016 0. Oll 0.005 0.546E-02 0.535E-02 0.517E-02 0.497E-02 0.445E-02 0.388E-02 0.338E-02 0.305E-02 0.284E-02 0.264E-02 0.238E-02 0.212E-02 0.183E-02 0.153E-02 0.122E-02 0.106E-02 0.783E-03 0.701E-03 0.538E-03 0.489E-03 0.375E-03 0.294E-03 0 .196E-03 0.163E-03 0. ll4E-03 0.489E-04 Cutoff 0.034 0. 041 0.048 0.056 0.063 0.070 0.078 0.085 0. 092 0.100 0.107 0.114 0.121 -----Fraction of Time--------------Check of Tolerance------- Base New %Change Probability Base New %Change 0.81E-02 0.71E-02 -12.1 j 0.81E-02 0.034 0.033 -1.4 0.59E-02 0.46E-02 0.34E-02 0.26E-02 0.19E-02 0.14E-02 0.96E-03 0.68E-03 0.41E-03 0.52E-02 0.45E-02 0 .33E-02 0.28E-02 0.23E-02 0.16E-02 O.llE-02 0.68E-03 0.47E-03 -11.1 I · 0. 59E-02 -2.8 j 0.46E-02 -2.4 j 0.34E-02 5.6 I 19.8 I 15.3 I 10.2 I 0.26E-02 0.19E-02 0.14E-02 0.96E-03 0.0 j 0.68E-03 16.0 j 0.41E-03 23.1 j 0.21E-03 -11.1 I 0.65E-04 0.00E+OO -100.0 I 0.21E-03 0.15E-03 0.26E-03 0.13E-03 0.15E-03 0.65E-04 Maximum positive excursion= 0.004 cfs ( 6.4%) occurring at 0.070 cfs on the Base Data:exwest.tsf and at 0.075 cfs on the New Data:wout.tsf Maximum negative excursion= 0.008 cfs (-18.7%) occurring at 0.043 cfs on the Base Data:exwest.tsf and at 0.035 cfs on the New Data:wout.tsf 0. 041 0.048 0.056 0.063 0.070 0.078 0.085 0. 092 0.100 0.107 0.114 0.121 0.034 0.048 0.055 0.066 0.075 0.081 0.086 0.092 0.102 0.109 0.113 0.119 -17.3 -1. 3 -1. 4 4.9 6.0 3.7 1. 3 0.0 2.3 1. 7 -0.6 -2.4 ( { 0 0 0- R ____ _ w'·:·,ut. du r + 1liton;iet.dur x N I 0 ~ * l 0 0 ,-.. if) <.O LL u ''-' Q; Q) '-oo _cq u <"') m ·-0 00 '-'+-,...._ '+, 8 ' d·+-"'--Prr_obTa_bril'01ty"TTErxrrc.e_e_d_en,c_e-.-,-,,-rn-,----,---,-T--r-r-t.,..,.,,---,---,--,--,-..,....,.TTT---.-.-"'-..'t!.-·....,...,.....,.. 10-4 VAULT FREQUENCY/ DURATION COMPARISON EVENDELL CORE PROJECT NO. 04009 1 \ ( ( 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: Detention Pond 3.00 H:lV 165. 00 ft ._/ 78.00 ft -"' 12870. sq. ft 25135. sq. ft 0.577 acres 6.15 ft 452.00 ft 109514. cu. ft 2.514 ac-ft V 6.15 ft 18.00 inches 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1. 75 0.206 2 4.00 3.00 0.358 6.0 3 5.10 2.00 0 .111 4.0 Top Notch Weir: None -·---Outflow Rating Curve: None 1:·15.r, o. i ' {.-; > Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 452.00 0. 0.000 0.000 0.00 0.02 452.02 258. 0.006 0 .011 0.00 0.04 452.04 516. 0. 012 0.016 0.00 0.05 452.05 645. 0.015 0.019 0.00 0.07 452.07 905. 0.021 0.022 0.00 0.09 452.09 1164. 0.027 0.025 0.00 0 .11 452.11 1425. 0.033 0.027 0.00 0.13 452.13 1685. 0.039 ·o. 030 0.00 0.15 452.15 1947. 0.045 0. 032 o.oo 0.27 452.27 3528. 0.081 0.043 0.00 0. 39 452.39 5131. 0 .118 0.052 0.00 0.51 452.51 6755. 0.155 0.059 0.00 0.63 452.63 8400. 0.193 0.066 0.00 0.75 452.75 10068. 0.231 0. 072 0.00 0.87 452.87 11757. 0.270 0.077 0.00 0.99 452.99 13467. 0.309 0.083 0.00 1.11 453.11 15200. 0. 349 0.088 0.00 1. 23 453.23 16955. 0.389 0.092 0.00 1. 35 453.35 18733. 0.430 0.097 0.00 1.47 453.47 20532. 0.471 0.101 0.00 1. 59 453.59 22355. 0.513 0.105 0.00 1. 71 453.71 24199. 0.556 0.109 0.00 1. 83 453.83 26067. 0.598 0 .112 0.00 1. 95 453.95 27958. 0.642 0 .116 0.00 2.08 454.08 30032. 0.689 0.120 0.00 2.20 454.20 31970. 0.734 0.123 0.00 2.32 454.32 33932. 0.779 0.126 0.00 Surf Area (sq. ft) 12870. 12899. 12928. 12943. 12972. 13002. 13031. 13060. 13090. 13266. 13444. 13623. 13803. 13984. 14166. 14349. 14533. 14718. 14904. 15091. 15279. 15468. 15659. 15850. 16058. 16252. 16446. st of ""f· 2.44 454.44 35917. 0.825 0.130 0.00 16642. 2.56 454.56 37926. 0.871 0 .133 o.oo 16838. 2.68 454.68 39959. 0.917 0 .136 0.00 17036. 2.80 454.80 42015. 0. 965 0.139 0.00 17235. 2. 92 454. 92 44095. 1.012 0 .142 0.00 17434. 3.04 455.04 46199. 1. 061 0.145 0.00 17635. 3.16 455.16 48327. 1.109 0.148 0.00 17837. 3.28 455.28 50480. 1.159 0.150 0.00 18040. 3.40 455.40 52657. 1. 209 0.153 0.00 18243. 3.52 455.52 54858. 1. 259 0.156 o.oo 18448. 3.64 455.64 57085. 1. 310 0.159 0.00 18654. 3.76 455.76 59335. 1.362 0.161 o.oo 18861. 3.88 455.88 61611. 1.414 0.164 o.oo 19069. 4.00 456.00 63912. 1.467 0.166 0.00 19278. 4.03 456.03 64491. 1. 481 0.169 0.00 19330. 4.06 456.06 65072. 1.494 0.176 o.oo 19383. 4.09 456.09 65654. 1. 507 0.189 o.oo 19435. 4 .13 456 .13 66433. 1.525 0.205 o.oo 19506. 4.16 456.16 67019. 1.539 0.225 0.00 19558. 4.19 456.19 67606. 1. 552 0. 249 0.00 19611. 4.22 456.22 68196. 1.566 0.275 0.00 19664. 4.25 456.25 68786. 1.579 0. 293 0.00 19717. 4.37 456.37 71165. 1.634 0.322 0.00 19929. 4.49 456.49 73569. 1. 689 0.347 0.00 20142. 4.61 456.61 75999. 1.745 0. 369 0.00 20356. 4.73 456.73 78455. 1. 801 0.390 0.00 20572. 4.85 456.85 80936. 1.858 0.408 0.00 20788. ( ' 4.97 456.97 83444. 1. 916 0.426 0.00 noo5. I 5.09 457.09 85978. 1. 974 0.443 o.oo 21224. 5.10 457.10 86190. 1.979 0.444 0.00 21242. 5 .12 457.12 86615. 1. 988 0.447 0.00 21279. 5 .14 457.14 87041. 1. 998 0.452 0.00 21315. 5.16 457.16 87468. 2.008 0.459 0.00 21352. 5.18 457.18 87895. 2.018 0.468 0.00 21388. 5.20 457.20 88323. 2.028 0.478 0.00 21425. 5.23 457.23 88967. 2.042 0.489 0.00 21480. 5.25 457.25 89397. 2.052 0.501 0.00 21517. 5.27 457.27 89828. 2.062 0.510 0.00 21553. 5. 39 457.39 92427. 2 .122 0.538 0.00 21774. 5.51 457.51 95054. 2.182 0.564 0.00 21997. 5. 63 457.63 97707. 2.243 0.587 0.00 22220. 5.75 457.75 100386. 2.305 0.609 0.00 22444. 5.87 457.87 103093. 2.367 0.630 0.00 22669. 5.99 457.99 105827. 2.429 0.650 0.00 22895. 6.11 458 .. 11 108588. / 2.493 0.669 0.00 23122. 6.15 458.15 109514. 2.514 0.675 0.00 23198. ----6.25 458.25 111844 \ 2.568 1.150 0.00 23389. 6.35 458.35 114192. \ 2.621 2. 010 0.00 23580. 6.45 458.45 116560. \ 2.676 3.120 0.00 23772. 6.55 458.55 118947. \ 2.731 4.430 0.00 23964. 6.65 458.65 121353. I 2.786 5. 910 0.00 24158. 6.75 458.75 123778. \. 2.842 7.350 0.00 24352. 6.85 458.85 126223. \ 2.898 7.890 0.00 24547. 6.95 458.95 128687. I 2.954 8.400 0.00 24742. 7.05 459.05 131171. \3. 011 8.870 0.00 24938. 7.15 459.15 133675. 3.069 9. 320 0.00 25135. 7.25 459.25 136199. 3·,?27 9.750 0.00 25333. \ '" ;,...., o't3, c.+ ' ' \ l i ;t ,,p/)"1--t--f!•t'~' 7,z 7, W"-0' ,< ) 7. 35 459.35 138742. 3.185 10.160 0.00 25531. 7.45 459.45 141305. 3.244 10.550 o.oo 25730. 7.55 459.55 143888. 3.303 10.930 0.00 25930. 7.65 459.65 146491. 3.363 11. 290 0.00 26131. 7.75 459.75 149114. 3.423 11. 64 0 0.00 26332. 7.85 459.85 151757. 3.484 11.990 o.oo 26534. 7.95 459.95 154421. 3.545 12.320 0.00 26736. 8.05 460.05 157104. 3.607 12.640 0.00 26940. 8.15 460.15 159809. 3.669 12.960 0.00 27144. Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft) l 3.90 ******* 2. 62 6.40 458.40 115486. 2.651 2 1.94 ******* 0.67 6.14 458.14 109398. 2 .511 3 1.96 0.58 0.58 5.60 457.60 96982. 2.226 4 2.32 ******* 0.50 5.25 457.25 89499·. 2.055 5 2.06 ******* 0.42 4.96 456.96 83147. 1.909 6 l. 22 0.17 0.20 4 .13 456.13 66386. 1. 524 7 1.59 ******* 0.16 3.61 455.61 56504. 1. 297 8 1. 73 ******* 0.14 2.92 454.92 44126. 1.013 ( I f Duration Comparison Anaylsis Base File: preeast.tsf New File: eout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change ,/ 0.170 0.82E-02 0.52E-02 -36. 7 I 0.82E-02 0.170 0.160 -5. B \/ 0.187 0.70E-02 0.44E-02 -36. 3 I 0.70E-02 0.187 0.164 -12.6 0.204 0.62E-02 0.38E-02 -3 8. 5 I 0.62E-02 0.204 0.165 -19.2 0.222 0.55E-02 0.37E-02 -32. 2 I 0.55E-02 0.222 0.168 -24.3 0 .239 0.50E-02 0.36E-02 -28.1 I 0.50E-02 0.239 0.174 -26.9 0.256 0.45E-02 0.35E-02 -22.7 I 0.45E-02 0.256 0.183 -28.4 0.273 0.40E-02 0. 34E-02 -13.5 I 0.40E-02 0.273 0.201 -26.4 0.290 0.36E-02 0. 34E-02 -5.5 I 0.36E-02 0 .290 0.248 -14.5 0.307 0. 31E-02 0.31E-02 0.5 I 0.31E-02 0.307 0.308 0.5 0.324 0.28E-02 0.29E-02 4.7 I 0.28E-02 0.324 0.339 4.6 0. 341 0.25E-02 0.27E-02 9.2 I 0.25E-02 0.341 0.361 5.8 0.358 0.23E-02 0.25E-02 10.8 I 0.23E-02 0.358 0.375 4.7 0.375 0.20E-02 0.23E-02 15.0 I 0.20E-02 0.375 0.387 3.3 0. 392 0.17E-02 0 .19E-02 9.6 I 0.17E-02 0 .392 0.399 1.9 0.409 0.14E-02 0.14E-02 3.5 I 0.14E-02 0.409 0. 412 0.7 0.426 0.12E-02 0.12E-02 -4.0 0.12E-02 0.426 0.422 -1. 0 0.443 O.lOE-02 0.99E-03 -1. 6 O.lOE-02 0.443 0 .441 -0.5 0.460 0.90E-03 0.90E-03 0.0 0.90E-03 0.460 0.464 0.9 0.477 0.82E-03 0.83E-03 2.0 0.82E-03 0.477 0.478 0.2 0.494 0.62E-03 0.72E-03 15.8 0.62E-03 0.494 0.519 5.0 0.511 0.52E-03 0. 64E-03 21.9 0.52E-03 0 .511 0.531 4.0 ( \ ! 0.528 0.39E-03 0.55E-03 41. 7 0.39E-03 0.528 0.560 6.0 0.545 0.33E-03 0.44E-03 35.0 0.33E-03 0.545 0.574 5.3 0.562 0.24E-03 0.38E-03 53.3 0.24E-03 0.562 0.594 5.7 0.579 0.20E-03 0.29E-03 50.0 0.20E-03 0.579 0.618 6.6 0.596 0.15E-03 0.23E-03 55.6 0.15E-03 0.596 0.639 7.1 0.613 0.13E-03 0.20E-03 50.0 0 .13E-03 0 .613 0.641 4.5 0.630 0. llE-03 0.15E-03 28.6 O.llE-03 0.630 0.649 2.9 0.648 O.llE-03 O.llE-03 0.0 0. llE-03 0.648 0.649 0.2 0.665 0.49E-04 0.65E-04 33.3 0.49E-04 0.665 0.668 0.5 0.682 0.33E-04 O.OOE+OO -100.0 0.33E-04 0.682 0. 671 -1.6 Maximum positive excursion= 0. 049 cfs 8. 3%) v' occuring at 0.590 cfs on the Base Data:preeast.tsf and at 0.639 cfs on the New Data:eout.tsf Maximum negative excursion= 0.073 cfs (-28.4%) occuring at 0.256 cfs on the Base Data:preeast.tsf and at 0 .183 cfs on the New Data:eout.tsf ( ( Flow Frequency Analysis Time series File:eout.tsf Project Location:sea-Tac ---Annual Flow Rate (CFS) 0.674 · 0.158 0. 503 0.142 0.204 0.424 0. 581 Peak Flow Rates--- Rank Time of Peak 2 7 4 8 6 5 3 1 2/09/01 20:00 12/29/01 10:00 3/06/03 22:00 8/26/04 7:00 1/08/05 3:00 1/18/06 23:00 11/24/06 8:00 1/09/08 10:00 2.61 computed Peaks EOUT.PKS -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft) Period 2.61 6.40 1 100.00 0.674· 6.15 2 25.00 0. 580v' 5. 60 3 10. 00 0.503 5.25 4 5.00 0.424 4.96 5 3.00 0.204"' 4.13 6 2.00 0 .158 3. 61 7 1. 30 0.142 2.92 8 1.10 1.97 6.35 50.00 Page 1 0.990 0.960 0.900 0.800 0.667 0.500 0.231 0.091 0.980 PREEAST.PKS ' I Flow Frequency Analysis Time series File:preeast.tsf Project Location:sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.698 2 2/09/01 18:00 0.999 1 100.00 0.990 0.238 7 1/05/02 16:00 0.698 2 25.00 0.960 0. 580 3 2/28/03 3:00 0. 580 , 3 10.00 0.900 0.060 8 8/26/04 2:00 0.559 4 5.00 0.800 o. 339 6 1/05/05 8:00 0. 516 5 3.00 0.667 0.559 4 1/18/06 20:00 0. 339,/ 6 2.00 0. 500 0. 516 5 11/24/06 4:00 0. 238 7 1.30 0.231 0.999 1 1/09/08 9:00 0.060 8 1.10 0.091 computed Peaks 0.899 50.00 0.980 ( ' f Page 1 . ) ( ) 0 <.D 0 X... ··,·-i, ·x.,: '>,, '><,, 'l >"<_\ E; 0 I .it , 1 j 1 11 ·f e> t,-, tT• "' t ··j l 1 1· X . .., ·--~ :1 ,_. . • l,. .. ~ ;-,<~~- ~+-oo-o-======-------·\_.-¥.--------------------0 ~.--., \ g+-----------------'*"i',i;:--·----------------~ r ~ v,O LL.. u . ._, ; \. .,\ ~ \~. If) 00 ------. "'J< ..co--1~---------------------~~·--·=·-~-------------... t-. 00 (/} ·-0 ··1 ··-.... "' .. --.;, ·--~ 0 '·1, 0 -Probability Exe eed en ce '1 o,-1-...£2...--,-ri -,....,: II :..,,-r~ .~ •. ,---.-~,r"T'TT" ,.-.,,--,-...--,-,,--,-,-,-,r,-r,Tr-,-.-,-r--r-r1 Tl Tl T1jjrT,--,-,1 ,1-'-r-1 T'I T'11 1rn1 j 10-~ 10-4 10-· 10-2 10·1 1 POND FREQUENCY/ DURATION COMPARISON _EVENDELL CORE PROJECT NO. 04009 { 448.0 Actual POND VOLUME CALCULATIONS CORE PROJECT NO. 04009 PROJECT NAME: EVENDELL INCREMENT AL VOLUME TOTAL VOLUME CF * = Total Live Storage in Pond **=Total Dead Storage in Pond 12..0 5"4. :::.;,: f~ V '-,/' o -1-.I-( "',lo~ i;; 6 \ __ ,--. 0 ?+ f-t·, 33>< ?t.. +· J. (Ufl3) / l.c ';,c _) -""\J L '2,, V 17). V). ""' {. ("ff B). >-/ "' { ( !, :; ?~f ,, 1-w-~--r)" 4-:: st "{,cn:i ~-F 152." 103>-t· -t. { (~2 .t 15") $ s-.• f,. ~SfJ7) 7 I :::. 1s.6 ~, 1-4086 + '56o 1 :;:., '2 S 3 SI s0 ft-· ) ( ) ( EAST BASIN The East Basin will utilize a wetpond to accommodate the required Level 2 Flow Control. The East Basin wetpond will receive runoff from the upstream tributary area as well as runoff from onsite. The upstream tributary area will be routed through the onsite storm drainage system to the wetpond. The allowable release rates will be established by the sum of the upstream tributary runoff plus the existing onsite runoff. The allowable release rate will be delineated as preeast.tsf and will be the sum of exeast.tsf + upsteast.tsf. The flows entering the wetpond will be the sum of the upstream tributary area and the developed site going to the pond. The total developed flows discharging to the pond will be delineated as posteast. tsf and will be the sum of deveast. tsf and upsteast.tsf. The East Basin wetpond (epond.rdf) was sized based on the 1998 KCSWDM and KCRTS Computer Software Reference Manual. See attached KCRTS printouts and attached pond volume calculation spreadsheet on the following pages. The stage-storage of the pond produced by KCRTS was utilized to calculate storage values at the elevations used to calculate the proposed wetpond that will actually be constructed onsite. The KCRTS interpolated storage values are listed below. Elevation Length x Width KCRTS Storage KCRTS Storage* 10% Safetv Factor 452 ]65' X 78' 0 0 454 177' X 90' 29,000 CF 31,900 CF 456 [89' X 102' 63,900CF 70,290 CF 458 201' X 114' 106,000 CF 116,600 CF Per the proposed Pond Volume Calculations spreadsheet on the following pages, the storage values at each delineated elevation is more than the required 10% safety factor storage values calculated above. The pond is therefore, adequately sized to accommodate the required 10% safety factor. ( East Basin W etpond Overflow Elevations The primary overflow for the pond is the riser pipe within the control structure. The water surface elevation above the riser for the 100 year developed flow is calculated assuming all orifices are plugged. To pass the 100-yearreturn period storm, 3.90 cfs, through a 18" overflow riser will require 0.47 feet of head (From Figure 5.3.4.H in the 1998 KCSWDM: Qweir = 9.739DH312 => 3.90 = 9.739(15/12)H312 => H = 0.41 feet). The primary overflow elevation would therefore, be equal to the elevation of the top of the riser plus the amount of head required to pass the 100-year return period storm, Elev. 458.15 + 0.41 feet= Elev. 458.55. The secondary overflow for the pond is the jailhouse weir located on the control structure catch basin. To pass the JOO-year return period storm at 0.41 feet of head, a minimum 4.60-foot wide jailhouse weir will be required. The jailhouse weir is analyzed as a notch weir using the following equation: Q = C (L-0.2H)H312 where Q = flow (3.90 cfs) C = 3.27 + 0.40 HIP H = head above weir (0.41 ft<= Use Same Head as Req'd Head Over Riser) P = depth of storage at weir (Elev. 458.15-Elev. 452.0 = 6.15 feet) L = length of the riser (ft) An emergency overflow spillway will be installed and constructed also as a 12-foot wide access road to the control structure. The emergency overflow/access road will be surfaced with asphalt. The emergency overflow spillway will be located at the primary and secondary overflow elevation 458.41. The 12' wide spillway can accommodate the 100-year return period flow of 3.90 cfs at a head of 0.2'. Q100 = C (2g)112 [(2/3)LH312 + (8/15)(Tan 8)H512 ] where Q100 = peak flow (3.90 cfs) C=0.6 G = 32.2 ft/sec 2 H = head above weir L = length of weir (12 ft) 8 = angle of side slopes (Tan 8 = 10) 3.90= 0.6 (2*32.2)112 [(2/3)(12)(H)312 + (8/15)(10)(H)512 ] H=0.2' ( ( C. Water Quality Volume Calculations Per the Water Quality Applications Map, Basic Water Quality Treatment shall be utilized to mitigate for the developed storm drainage flows. The wet portion of the wetpond and wetvault will satisfy this requirement. The required volume will be designed per KCSWDM Section 6.4.1.1. The following variables were used in the calculation: Volume Factor (f) = 3 Rainfall = 0.039 feet or 0.47 inches Area = developed basin Where A; = area of impervious surface ( sf) Atg = area of till soil covered with grass ( sf) Atf= area of till soil covered with forest (sf) A 0 = area of outwash soil covered with grass or forest ( sf) V, = [0.9A; + 0.25Atg + 0.lAtf+ O.OlAo] * (R/12) vb= f"Vr WEST BASIN Vb= 3*[(0.9)(1.30) + (0.25)(0.51)]0.039 * (43560sf/ac) = 6,613 CF The dead storage portion of the wetvault is 4.06' deep and has a surface area of 17 feet by 96 feet. The dead storage therefore, has a volume of 6,626 CF which exceeds the required 6,613 CF. A minimum flow path length to width ratio of 3: I is required for the wet portion of the vault. The average width is 17' and the length from inlet to outlet is 199'. The length to width ratio for the vault is therefore, 199'/l 7' = 11.7:1 which exceeds the required minimum 3: I. The sediment storage within the 1st cell was designed with l' of average storage and the sediment storage within the 2nd cell was designed with 0.5' of average storage with bottom slopes within the vault sloping toward the exterior walls. See email on the following pages for allowance to slope the bottom toward the exterior walls rather than towards the center. The average bottom elevation within the 1st cell is (465.44 + 465.59 + 466.29 + 466.44)/4 = 465.94. The top of the sediment storage within the 1st cell is elevation 467.02. The average storage depth within the l't cell is therefore, 467.02- 465.94 = 1.08' which exceeds the required 1' average. The average bottom elevation within the 2"d cell (following the 1st cell) is ( 466.94 + 466.09)/2 = 466.52. The top of the sediment storage within the 2"d cell (following the 1st cell) is elevation 467.02. The average storage depth within the 2"d cell (following the 1st cell) is therefore, 467.02 - 466.52 = 0.5 ', which is equal to the required 0.5' average. The average bottom elevation with the 2"d cell(detention only) is (471.00 + 470.15)/2 = 470.58. The top of the sediment ( ! i storage within the 2nd cell (detention only) is elevation 471.08. The average storage depth within the 2nd cell is therefore, 471.08-470.58 = 0.5', which is equal to the required 0.5' average. EAST BASIN Vb= 3*[(0.9)(6.69) + (0.25)(3.37)]0.039 * (43560sf/ac) = 34,980 CF The dead storage portion of the wetpond has a volume of37,31 l CF which exceeds the required 34,980 CF. See Pond Volume Calculations spreadsheet in Section 4B of this report. LENGTH TO WIDTH RATIO A minimum flow path length to width ratio of 4: 1 is required for the wet portion of the pond. (see the attached "Length to Width Ratio" exhibit). If this 4:1 ratio can be achieved then it is not required for the pond to have a dividing berm. The location of the flow path and and the location that the width of the pond is measured is at one half the water depth. The MWS of the dead storage is 452.0 and the pond bottom is 448.0. Therefore the travel path and width is measured at elevation 450.0 ( 452.0 + 448.0 / 2). The travel path at this point is 195 feet and the average width of the pond is 39'. This calculates to a length to width ratio of 5:1 (195/39 = 5.0) which is greater then the 4:1 required. ) ( t ' C· ·-----· />..\Jr,. ~1·101"1 0 '1 f;3 (j ':; q S' c,o ( t14 30 7"'1 sa • ;4q .. . ···45..'/•·'--·· -' -·-. --. -,f!~ -. -. "if ··----·· l . -· • ---···· ,f."if; .... ,_ . · 1,,: _,"'; lA C8 ; DETENTION POND PLAN st:AJL· ,-20· I f/; '\O' ,~s --3'\ -LS:o:=} 14·. I I: I I I ~A;S'T po"J~ .i C84 ,i~ I '' I I ( RE: Evendell Vault Revision Pagel of l CORE -Gina Brooks From: Hancock, Dave [Dave.Hancock@METROKC.GOVJ Sent: Tuesday, July 20, 2004 7:08 AM To: CORE -Gina Brooks Cc: Walken, Jerry; Wong, Wylie Subject: RE: Evendell Vault Revision Gina, I have discussed your proposed revision to the vault design for the plat of Evendell with staff, and have determined that sloping the floor towards the exterior walls will not impact our ability to maintain the systemin the future. Sediment removal will be available through the access ports, also located along the exterior of the vault. I would recommend that Wylie document this revision by approving a minor field change, so the revision will not be challenged when the project is inspected at later dates. If you need additional assistance please feel free. to e-mail me or call me at 206-296-8230. Dave Hancock -----Original Message----- From: CORE -Gina Brooks [mailto:grb@coredesigninc.com] Sent: Monday, July 19, 2004 1 :39 PM To: dave.hancock@metrokc.gov Subject: Evendell Dave, I am hoping you can help me document your approval of the vault design for Evendell in regards to the bottom sloping towards the exterior walls rather than the interior. Per Jerry Walken, ifl can get app,roval from maintenance for the sloping of the vault bottom towards the exterior walls then Comment 3 under Title "Sheet C4.32" of the 1st Review Comments will become non-applicable. Please reply to this email with your approval so that I may attach this email to my response letter for Wylie Wong's review. Thanks for your help. Gina R. Brooks, P .E. Core Design, Inc. 14711 NE 29th Place, Suite 101 Bellevue, WA 98007 425-885-7877 425-885-7963 (fax) 7/20/2004 KING COUNTY WATER QUALITY APPLICATIONS MAP EVENDELL CORE PROJECT NO. 04009 { l ( 6.4.1 WETPONDS -BASIC AND LARGE-MEI'HODS OF ANALYSIS FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES (FEET) ·'~ / . i. :; ' i :[" ,...-ii ·~~ 0.54" (0.045') [T?J Incorporated Area ......c:=::i River/Lake Major Road 0.47· (0.039') 0.47" (0.039') NOTE: Areas east of the easternmost lsopluvlal should use 0.65 inches unJess rainfaO data is avallable for the location of interest 24 The mean annual stonn Is a conceptual stonn found by dividing the annual precipitation by the total m.mber al stonn events per year 0.52" ( 0. 043 ' 6. S 6 • (0.047') LA 1.0 LA l.2 Q • 9 ... .,u,uu co,.nT () result, generates large.amounts of runoff. For this application, till soil types include Buckley and bedrock soils, and alluvial and outwash soils that have a seasonally high water table or are underlain at a shallow depth ·(less than 5 feet) by glacial till. U.S. Soil Conservation Service (SCS) hydrologic soil groups that are classified as till soils include a few B, most C, and all D soils. See Chapter 3 for classification of specific SCS soil types. 1998 Surface Water Design Manual 9/1/98 .6-69 . ·) Wetland Recharge Calculations ( i ( The following calculation compare the monthly volume of runnoff to the wetland before and after development. 4 lots have been selected to discharge roof and footing drains to recharge the wetland. Predeveloped Condition Total Upstream Area 54,000 sf Using the same relative landcovers as the east basin (see Drainage Report) Total Basin 10.06 Ac 6.62 Ac 3.26 Ac 0.18 Ac Therefore, Landcovers for Predeveloped Basin: Total Basin 1.24 Ac 0.82 Ac 0.40 Ac 0.02 Ac From WetPRE Timeseries, Total runoff for 8 Water Years = = 1.24 Ac % of Basin Forested 66% Pasture 32% Impervious 2% Forested % of Basin 66% Pasture 32% Impervious 2% Predeveloped Condition = 6.5 Ac-FT 2,949 cf/month Developed Condition Area east of wetland, unchanged in landcover Using the same relative landcovers as the east basin (see Drainage Report) Areas 0.38 Ac 0.25 Ac 0.12 Ac 0.01 Ac 4 Lots conveying to Wetland (Lots 34,35,37 and 38) Area (measured) 25,060 sf subract 4 driveways (20'x 30') 2400 sf Building Area 22,660 sf assume 70% buildings Total Basin (A+B) 15,862 sf 0.36 Ac 0.74 Ac 0.25 Ac 0.12 Ac 0.37 Ac = (A) . Forested Pasture Impervious = = (B) Forested Pasture Impervious From WetDEV Timeseries, Total runoff for 8 Water Years = Developed Condition = 0.38 Ac 0.58 Ac 0.52 Ac 8.7 Ac-FT 3,948 cf/month ( ·~ .. ~ . --o'"· cl ~ r • d 2-~) ?r(~eu ~ ~ l c-} .. . ·: ... ::'''':~~':'.(~~;.~~;;,:::,,r'!'"'"--~:.y;.~.-. -- -....;.., ... ·-··""'· =,;. ----- II' I '· I I ~~ ~ .,,> ·----,,.;_,_ \ I \ \ \ I \ \ ' ' ' I I, I ', I ~ \' ' \ \ ", I, .· '\ \ I .\, I l I i s L ! 1· ' ' , . 1! ; ( ' CORE DESIGN, INC. BELLEVUE WA 98007 Regarding Hearing Examiners Condition #19-a Core Project No: 04009 11/10/04 On Nov. 2, 2004, a field visit was performed to verify/review the drainage issue associated with the existing ditch in the vicinity of the easterly line of Lot 12, Rich Lea Crest (address 16046 S.E. 142nd Street). A drainage complaint was filed by the adjacent homeowner, Don Gregg, on Jan. 10, 1997 (complaint #97-206). A condition of approval of the Evendell Project includes stabilizing and re-grading approximately 50 to 100 feet of the existing channel to adequately resolve flooding that has occurred in this area. Based on field observations, this work appears to have been completed. See attached photos. The timing of the work performed is unknown, but probably occurred more than _one year ago as the ditch excavation has naturally re- vegetated. The ditch is now approximately 5' wide and 5' deep in this location, which is substantially larger than upstream or downstream of Lot 12. 04009 HE Condition 19a, 11/10/04, page I "'-. ~ ii ' ::;, ~--1 Sl n ii V. i~------ .~· '(' ·, . \; ., l Lo~ ft -rt e, w f=:Xt4771iv o· t>r1"dh' (\ j) .. { L-o Ole,..., l. WE,.,., e (!_f;.,._;,/?ftL,I IN£ i, i:-f= XI ~-r,w (,, i.:>l•CH /tLO.-.J6 '"tffc /J/Oft7H /JflO(t;f!7y ltrv'€ OF l-OT I-Z..1 fl-A-7 OF-r...1cH t.,fli t!flF'7T FfZ.01t1-N..€. COfl-~'-rt OF L-O, II, \:;:>t,c>-1 l"7 ftPf'~o)f.1,ri,1i7t;(.:-f ~' "PGfP., 5' vJ,1;>1: A7 ,,,.,~ ~07'?0M h..>1> lt11-/1?1 \JV I f7 fi-f'r7 -n,16 -?'<9f. • ( \ ·- ( 11/09/2004 17:19 2535390514 SOUNDBUILT HOMES PAGE 02 Issaquah School District No. 411 565 NW Holly Slraat • Issa ueh, WA 98027.-2899 • PhCl'le 425 837-7000 Janet N. Barry, Ed. D. November 7, 2004 Kurt WIison, Land Acquisition Manager SBI Developing, LLC. Box73790 Puyallup, WA 98373 RE: Pedestrian Access to LlbertyHigh School Dear Kurt: The proposed pedestrian connection ilia Trad "A' in the existing Liberty Lane subdivision has been reviewed and approved. · This should provide the necessary authprizatlon requested by King County and allow your design work to proceed. Let me know If you need anything else to continue the process. . If you need access to the school site to take measurements, gather information etc. contact the school ·office where you. will need to signsin and sign-out. Please forward design drawings to me as they are developed for review. and approval. Si Crawford D ctor of Ca pita I Projects Board of Dlractom Constance L Fletcher• Larry W. Ishmael • Marx Wamer • Michael Winkler• Jan Wold•eth Superintendent I •l60TH••brtc14••ANALYSlS•••~••ExlSTING••@•o0TFALL ' .. · .. ·.·.·.·.·.· ,',',',', .. ·.·.·:. ,','. ... ,', ,', ,',', .. ·.· .. '. ' . ' .·.·.· .. ,',', . ::.·.·: .·. ' : ...... ·,·.·' ·.·''. ·, .· ... ·.'. ' .. ·' ·. '·.· .. '.·.· .. ·.' .·'' .· .. ' . ·.· . .' DITCH DATA: BOTTOM WIDTH (FT) = 2.00 JOB NAME: £YENDELL LEFT SIDE SLOPE (L:1) 3.00 JOB#: 04009 RIGHT SIDE SLOPE (R:l 3.00 OPERATOR: S.R.B. BOTTOM SLOPE (FT/FT 0.0200 DATE: 10/9/2004 MANNING'S n = 0.050 FLOW FLOW WETTED HYDRAULIC DITCH FLOW DEPTH AREA PERIMETER RADIUS CAPACITY VELOCITY (FEET) (SQ FT) (FEET) (FEET) (CFS) (FPS) 0.00 0.0000 0.0000 0.0000 0.000 0.000 0.05 0.1075 2.3162 0.0464 0.058 0.543 0.10 0.2300 2.6325 0.0874 0.190 0.828 0.15 0.3675 2.9487 0.1246 0.385 1.049 0.20 0.5200 3.2649 0.1593 0.642 1.235 0.25 0.6875 3.5811 0.1920 0.962 1.399 0.30 0.8700 3.8974 0.2232 1.346 1.547 0.35 1.0675 4.2136 0.2533 1.796 1.683 0.40 1.2800 4.5298 0.2826 2.317 1.810 0.45 1.5075 4.8460 0.3111 2.909 1.930 0.50 1.7500 5.1623 0.3390 3.576 2.043 0.55 2.0075 5.4785 0.3664 4.321 2.152 0.60 2.2800 5.7947 0.3935 5.146 2.257 0.65 2.5675 6.1110 0.4201 6.054 2.358 0.70 2.8700 6.4272 0.4465 7.047 2.455 0.75 3.1875 6.7434 0.4727 8.129 2.550 0.80 3.5200 7.0596 0.4986 9.303 2.643 0.85 3.8675 7.3759 0.5243 10.570 2.733 0.90 4.2300 7.6921 0.5499 11.933 2.821 0.95 4.6075 8.0083 0.5753 13.396 2.907 1.00 5.0000 8.3246 0.6006 14.960 2.992 1.10 5.8055 8.9390 0.6495 18.300 3.152 1.20 6.7200 9.5895 0.7008 22.283 3.316 1.24 7.1230 9.8627 0.7222 24.100 3.383 1.30 7.6700 10.2219 0.7503 26.620 3.471 1.40 8.6800 10.8544 0.7997 31.431 3.621 1.50 9.7500 11.4868 0.8488 36.737 3.768 1.60 10.8800 12.1193 0.8977 42.556 3.911 1.70 12.0700 12.7517 0.9465 48.906 4.052 1.80 13.3200 13.3842 0.9952 55.805 4.190 1.90 14.6300 14.0167 1.0438 63.271 4.325 2.00 16.0000 14.6491 1.0922 71.322 4.458 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN: ON-SITE DRAINAGE SYSTEM The conveyance system for the site was designed for both the 25-year, 24-hour storm and the 100-year, 24-hour storm. A backwater analysis sheet was generated for both the 25- year and 100-year return period storms. Total flows from each basin and upstream tributary area using 15-minute time steps were calculated. The inputs to calculate the total flows were the same for the West Basin and Upstream Tributary Area (See Section 4 of this report) but, varied for the East Basin. The total flows calculated for the East Basin excludes the Storm and Recreational Tracts (Tracts L & M) since these areas do not enter the conveyance system. The inputs used for the KCRTS analysis for the East Basin is summarized in the table below: REVISED EAST BASIN Total Area= 8.94 acres DEVELOPED CONDITIONS (deast15) GROUND COVER AREA(acre) Till-Grass (Landscaoing) 2.25 Impervious 6.69 The West Basin flow frequency analysis is attached as dwest15.tsf. The total KCRTS 25- year return period flow and the JOO-year return period flow for the West Basin are 1.28 cfs and 1.79 cfs consecutively. The East Basin flow frequency analysis is attached as deast15.tsf. The East Basin Upstream Tributary flow frequency analysis is attached as upeast15.tsf. And the combination ofboth time series for onsite and upstream areas for the East Basin is attached as postel5.tsf. The total KCRTS 25-year return period flow and the 100-year return period flow for the East Basin are 6.54 cfs and 9.06 cfs consecutively. For simplicity, large basin areas going to multiple catch basins were used. For the West Basin, it was simply assumed that the total flows for the entire basin enter all drainage pipe. Flows for the large areas within the East Basin were simply calculated as a portion of the overall 15-minute flows based on the area ratio. RECEIVED NOi/ 1 7 'l004 KING COUNn' LANO USE SEHIJICES There will be four large basins delineated for the East Basin. See Catch Basin Subbasin Map on the following pages. The flows for each subbasin is calculated below. Subbasin Subbasin Percent 25-year Percent 100-year Return Area Area/East Basin Return Period Period Flow Flow Basin A 0.51 AC 0.51/8.94 = 5.70%*6.54 = 5.70%*9.06 = 0.52 cfs 5.70% 0.37 cfs Basin B 0.80AC 0.80/8.94 = 8.95%*6.54 = 8.95%*9.06 = 0.81 cfs 8.95% 0.59 cfs Basin C 3.87 AC 3.87/8.94 = 43.29%*6.54 = 43.29%*9.06 = 3.92 cfs 43.29% 2.83 cfs Basin D 3.76 AC 3.76/8.94 = 42.06%*6.54 = 5.70%*9.06 = 3.81 cfs 42.06% 2.75 cfs Total 8.94 AC 8.94/8.94 = 6.54 cfs 9.06 cfs 100% The tailwater elevations within the wetpond and wetvault were derived from the KCRTS outfall information (wout.tsf and eout.tsf). The tailwater elevations within the wetvault for the 25-year and 100-year return periods are El. 477.62 and El. 478.50 consecutively. The tailwater elevations within the wetpond for the 25-year and I 00-year return periods are El. 458.15 and El. 458.40, respectively. The backwater analysis was performed to ensure that during the 25-year design storm, the maximum water surface elevation in each strncture did not exceed an elevation equal to 0.5' less the rim and during the 100-year design storm, ensuring that if the maximum water surface elevation does exceed the rim, topography of the basin would allow the overflow to be conveyed to the next downstream catch basin or the topography would allow for ponding without causing strnctural damage. During the 25-year, the headwater· elevations do not exceed 0.5' less the rim. During the 100-year, the headwater elevations exceed the rims of CB 3, CB 30 and CB 31. Overflow at CB 3 will simply drain to the next downstream catch basin. Drainage overflowing CB 30 and CB 31 will pond and overflow the crown of the road before jumping the curb and flow to the next downstream catch basin. OFF-SITE DRAINAGE SYSTEM Some culverts along SE 136'h Street and ! 60'h Avenue SE are to be relocated, added, and/or replaced. Also, due to proposed shoulder construction along l 60'h Avenue SE, the existing ditch along the west side of the road will be relocated behind the proposed shoulder. A tightlined storm line will bypass stormwater from the ! 60'h roadside ditch · · and areas upstream of the project site down to the a discharge point near the ooutheast J,1.-oy..[/1-a.,,...,{· comer of the proposed Nichols development. Stormwater from the Evendell plat's stormwater pond will enter this system at the project site's southeast comer, upstream of the system's discharge point. The off-site drainage system was sized to convey the 25- year and I 00-year flows calculated in the Level 3 Downstream Drainage Analysis by Haozous Engineering, dated August 26, 2002. See Section 6 of this report for a copy of the report. The King County Backwater (KCBW) program was used to analyze the capacity ofthis entire system along 160'\ including the tightlined portion, the open channel and the culvert under 136'h Street. The output from the KCBW analysis follows at the end of this section. In order to determine a tailwater depth at the conveyance system's discharge point, the existing ditch downstream of this point was analyzed to determine the flow depth that would be realized to convey the I 00-year storm event flows. The flows provided in the Haozous report at node # 117 were used to analyze this system. The discharge from the Evendell detention pond will match the existing site discharge for the 25-year event, but will exceed the existing by 1.6 cfs for the I 00-year event. So, the total flow at the downstream discharge point will be: Q25 = 18.3 cfs and Q 100 = (22.5 + 1.6) = 24.1 cfs. In Section 3 of their report, Table l -Description of Downstream Conveyance System , describes the ditch in this area as having a 2' wide bottom, 1.5' of depth, 3: I sideslopes and a 2% slope. A Manning's 'n' value of0.050 was used to represent a "constructed channel with a clean bottom and brush on the sides". As shown on the attached spreadsheet titled J 6dh Ditch Analysis -Existing@ Outfall, the flow depth in the ditch would be 1.26 feet and the velocity 3.4 fps, when conveying the 100-year storm event flow of 25 cfs. The outfall has an invert elevation of 444.86, so the tail water elevation was determined to be 446.12, which was used for all of the KCBW analyses, both for the 25-year and 100-year events. Flows input into the KCBW program for each segment of the conveyance system were adjusted to account for the storm water contributed to the system by runoff from 160'h and from the Evendell pond discharge. The flows used were as follows: Downstream of Outfall lB: CB I to Outfall lB: Input to CB I from Pond: Input to CB I from l 60'h: CB IA to CB I and upstream: Qz-2 {cfs) 18.3 17.6 0.7 0.4 16.5 Q100 {cfs) 24.1 23.0 2.6 0.5 19.9 The same flow values calculated for the run from CB IA to CB 1 were used for the rest of the system upstream of CB IA, rather than attempting to approximate the gradually increasing flows that will enter the open channel due to runoff from 160'\ As shown on the KCBW program output that follows this report, the system of pipes, open channel and culverts proposed for the project's frontage on 1601 h Avenue SE will have adequate capacity to convey the design storm events. Additionally, the velocity in the open channel portion of this system is shown to be less than 5 fps, so grass lining is appropriate for this channel. Plat of Evendell -KCBW Program Output BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:04009bl.bwp Surcharge condition at intermediate junctions Tailwater Elevation:446.12 feet Discharge Range:17.6 to 23. Step of 5.4 [cfs] Overflow Elevation:461. feet Weir:NONE Upstream Velocity:3.4 feet/sec /lu.tfdl If, C.Jl I a PIPE NO. 1: 59 LF -24"CP @ 1.001 OVERFLOW-EL: 449.91 BEND: OUTLET: 444.86 INLET: 445.45 INTYP: 5 JUNC NO. l: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.00 Q(CFS) HW (FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 17.60 23.00 2.09 2.65 447.54 * 0.012 1.52 1.26 1.26 1.26 1.52 ***** 448.10 * 0.012 1.71 1.54 1.26 1.54 1.71 ***** 2.09 2.65 PIPE NO. 2: JUNC NO. 2: 239 LF -24"CP @ 1.801 OVERFLOW-EL: 454.77 BEND: OUTLET: 445.45 INLET: 449.75 INTYP: 5 0 DEG DIA/WIDTH: 6.0 Q-RATIO: 0.18 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 17.60 2.26 452.01 * 0.012 1. 52 1. 05 2.09 2.09 1. 52 ***** 2.26 23.00 2. 95 452.70 * 0.012 1. 71 1. 24 2.65 2.65 1. 71 ***** 2.95 c~ l . C--13 IA PIPE NO. 3: 291 LF -24 11 CP @ 2.841 OUTLET: 449.75 INLET: 458.00 INTYP: 5 Q(CFS) HW (FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 14. 92 2.04 460.04 * 0.012 1. 40 0 .. 84 2.26 2.26 1. 40 ***** 2.04 19.49 2.66 460.66 * 0.012 1.59 0.97 2.95 2.95 1.59 ***** 2.66 BACKWATER COMPUTER PROGRAM FOR OPEN CHANNELS Channel Data Filename:04009b3.bwc Tailwater from HW/TW File:04009bl.bwt Discharge Range:16.5 to 19.9 Step of 3.4 [cfs] STATION 0.00: INVERT= 461.00 FT EC=l.15 Q-RATI0=0.00 CROSS-SECTION DATA: DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) N-FACTOR 0.050 4.50 1.50 4.50 1.50 Q (CFS) Y1 (FT) WS ELEV. * YC-IN YN-IN Q-TW TW-HT N-Yl A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 1.17 462.17 * 1.17 1.15 16.50 0.00 0.050 4 .11 7.40 4.02 **************** 19.90 1. 26 RANGE EXCEEDED IN HW/TW FILE -DATA EXTRAPOLATED************* 462.26 * 1.26 1.23 19.90 o.oo p.oso 4.76 7.97 4.18 ****REACH NO. 1: STATION 110.00: CROSS-SECTION DATA: LENGTH= 110.00 FT INVERT= 466.00 FT AVG.GRADE= 4.55% **** EC=l.15 Q-RATI0=0.00 DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) N-FACTOR 0.050 4.50 1.50 4.50 1.50 Q(CFS) Yl (FT) WS ELEV. * YC-IN YN-IN YC-OT YN-OT N-Yl A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 19.90 1.16 1. 24 ****REACH NO. 2: STATION 203.00: CROSS-SECTION DATA: 467.16 * 1.17 1.16 1.17 1.15 0.050 467.24 * 1.26 1.24 1.26 1.23 0.050 4. 04 4.61 LENGTH= 93.00 FT INVERT= 470.00 FT AVG.GRADE= 4.30% **** EC=l.15 Q-RATI0=0.00 7.34 4.09 7.84 4.31 DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) 4.50 1.50 N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) 4.50 1.50 Q (CFS) Yl(FT) WS ELEV. * YC-IN YN-IN YC-OT YN-OT N-Yl N-FACTOR 0.050 A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 19.90 1.16 1. 24 471.16 * 1.17 1.15 1.17 1.16 0.050 471.24 * 1.26 1.23 1.26 1.24 0.050 4·. 04 4.61 7.34 4.09 7.84 4.31 ****REACH NO. 3: STATION 290.00, CROSS-SECTION DATA: LENGTH= 87.00 FT INVERT= 474.00 FT AVG.GRADE= 4.60% **** EC=l.15 Q-RATI0=0.00 DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) 4.50 1.50 N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) 4.50 1.50 Q(CFS) Yl (FT) WS ELEV. * YC-IN YN-IN YC-OT YN-OT N-Yl N-FACTOR 0.050 A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 19.90 1.17 1.26 475.17 * 1.17 l,.20 1.17 1.15 0.050 475.26 * 1.26 1.28 1.26 1.23 0.050 4.11 4.76 7.40 4.02 7.97 4.18 ****REACH NO. 4: LENGTH= 110.00 FT INVERT= 478.00 FT AVG.GRADE= 3.64% **** STATION 400.00, EC=l.15 Q-RATI0=0.00 CROSS-SECTION DATA: DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) 4.50 1.50 N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) 4.50 1.50 Q (CFS) Yl (FT) WS ELEV. * YC-IN YN-IN YC-OT YN-OT N-Yl N-FACTOR 0.050 A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 19.90 1.28 1. 38 479.28 * 1.17 1.28 1.17 1.20 0.050 479.38 * 1.26 1.38 1.26 1.28 0.050 4.92 5.71 8.10 3.36 8.73 3.48 ****REACH NO. 5: LENGTH= 30.00 FT INVERT= 478.75 FT AVG.GRADE= 2.50% **** STATION 430.00, EC=l.15 Q-RATIO=O. 00 CROSS-SECTION DATA, DIST/STAGE IS MEASURED FROM INVERT; N-FAC IS MEASURED BETWEEN STAGES LEFT(FT) STAGE(FT) 4.50 1.50 N-FACTOR 0.050 * * RIGHT(FT) STAGE(FT) 4.50 1.50 Q (CFS) Yl (FT) WS ELEV. * YC-IN YN-IN YC-OT YN-OT N-Yl N-FACTOR 0.050 A-Yl WP-Yl V-Yl ******************************************************************************* 16.50 19.90 1. 28 1. 38 480.03 480.13 ROUTING DATA RESULTS: STAGE (FT) DISCHARGE(CFS) 0.00 0.00 1.17 16.50 1.26 19.90 ROUTING DATA RESULTS, STAGE (FT) DISCHARGE(CFS) 0.00 0.00 1.17 16.50 1. 26 19.90 * 1.17 * 1.26 0.00 0.00 STORAGE(CU-FT) 0.0 1821. 2 2100.1 STORAGE(CU-FT) 0.0 1821.2 2100.1 File Opened for Writing:04009b3.bwt Save results to HW/TW file,04009b3.bwt File Opened for Writing:04009b3.RS1 Save results to Routing file:04009b3.RS1 1.17 1. 26 1.28 0.050 1.38 0.050 PERM-AREA(SQ-FT) 0.0 3228.9 3466.9 PERM-AREA(SQ-FT) 0.0 3228.9 3466.9 4.92 5.71 8.10 8.73 3.36 3.48 BACKWATER PROGRAM FOR ROUND/ARCH CULVERTS Tailwater from HW/TW File:04009b3.bwt Discharge Range:16.5 to 19.9 Step of 3.4 [cfs] Overflow Elevation:483.5 feet Weir:NONE Upstream Velocity:4. feet/sec CULV NO. 1: 94 LF -24"CP @ 0.80% OUTLET: 478.75 INLET: 479.50 INTYP: 3 TW DATA ADJUSTED BASED ON CROSS-SECTIONAL AREA Q-TOT(CFS) TW(FT) TW-ELEV(FT) Q-ADJ(CFS) AREA(SQ-FT) ******************************************************************** 0.00 0.00 478.75 0.00 0.00 16.50 1. 28 480.03 16.50 2.12 19.90 1. 38 480 .13 19.90 2.31 Q(CFS) HW (FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************************************************************************* 16.50 2.35 481.85 * 0.012 1. 47 1. 30 1. 28 1. 30 1.47 ***** 2.35 19.90 3.12 482.62 * 0.012 1. 61 1.50 1.38 1. so 1. 61 ***** 3.12 @ King County Road Services Division Department of Transportation KSC-TR-0222 201 South Jackson Street Seattle, WA 98104-3856 December 23, 2004 David E. Cayton 14711 NE 29°' Place, Suite IO I Bellevue, WA 98007 RE: Road Variance L04V0056 -Evendell Plat -Related File LO 1POO 16 Dear Mr. Cayton: Thank you for submitting your application for road variances from the King C::ounty Road Standards (KCRS). You requested variances from Sections 2.10, 5.11 and 2.13 of the KCRS concerning the intersection curb radius, clear zone and entering sight distance (ESD) at the intersection of SE 136th Street and 56th Avenue SE. We have reviewed your proposal and agree that the proposed 500 feet of ESD to the north (right) at the intersection will be acceptable. The 500 feet ofESD is the American Association of State Highway and Transportation Officials (AASHTO) manual minimum for the ten over posted design speed of 45 MPH. The proposed 25-foot curbs return radius at the northeast comer of the intersection is also acceptable given the property constraints. A 25-foot radius was previously allowed at the northwest comer of the intersection by a prior road variance. I approve a variance to allow the proposed 500 feet ofESD (to the north) with the condition that the applicant's engineer must certify that the 500 feet ofESD has been provided prior to construction approval. I also approve a variance to allow the 25-foot intersection curb return radius. The proposed minimum separation of three feet from the 25-foot inside turning radius to a short keystone wall at the northeast comer of the intersection is necessary due to property constraints. No sidewalk is required for this development along the north side SE 136th Street but a sidewalk will be provided along the south side.· The existing five foot paved walk on the east side 156th Avenue SE will be maintained. When the property abutting the northeast corner subdivides, a minimum 35-foot radius can be provided and the retaining wall moved to ?·5 feet from face of vertical curb. I approve a variance for the comer of the retaining wall at three feet from the intersection curb line. Note that the curb cannot be extended all the way around the northwest corner because the five-foot paved walk would be obstructed. The reduced 25-foot curb radius should extend as a stripe from the half delta to the edge of traveled way along 156°' Avenue SE. David E. Cayton December 23, 2004 Page2 The variance request for the 390 feet of westward ESD for the driveway at ST A 4+00 on SE 136th Street is also approved with the condition that the applicant's engineer must certify that 390 feet ofESD has been provided prior to construction approval. The 390 feet meets 2001 AASHTO for the design speed of35 MPH. A copy of staff's analysis, findings and conclusions is enclosed. If you have any questions, please feel free to contact Craig Comfort, Road Variance Engineer, Traffic Engineering Section, at 206-263-6109. Sincerely, Paulette Norman, P.E. County Road Engineer PN:CC:kc cc: James Sanders, P.E., Development Engineer, Land Use Services Division (LUSD), Department of Development and Environmental Services (DDES) Pete Dye, P.E., Senior Engineer, LUSD, DDES Linda Dougherty, Division Director, Road Services Division (RSD), Department of Transportation (DOT) Matthew Nolan, P.E., County Traffic Engineer, Traffic Engineering Section, RSD, DOT Fatin Kara, P.E., Supervising Engineer, Traffic Engineering Section, RSD, DOT Kris Langley, Senior Engineer, Traffic Engineering Section, RSD, DOT Craig Comfort, P.E., Road Variance Engineer, Traffic Engineering Section, RSD, DOT ® King County Road Bervioos Division Department of Transportation Traffic Engineering Section MS KSC·TR·0222 201 South Jackson Street Seattle, WA 98104 December 23, 2004 TO: Variance File FM: Craig Comfort, P.E., Road Variance .Engineer, Traffic Engineering Section RE: Road Variance L04V0056 -Evendell Plat-Related File LOIP0016 Applicant's Presentation: . l. Evendell is an approved 53-lot prelimin:'2' plat south of SE 136th Street and east of 156th Avenue SE. The plat frontage on SE 136 Street starts 197 feet east of 156th Avenue SE. The plat conditions require that SE 136th feet be improved to urban neighborhood collector standards and connected to 156th Avenue SE. Sidewalk is only required on the south side · of SE 136th Street. Presently, SE 136th Street is an unopened right-of-way (ROW) for several hundred feet east of 156th Avenue SE. 2. There is insufficient ROW at the northeast comer of the intersection of 156th Avenue SE and SE 136th Street to provide the minimum 35-foot radius required by the King County Road Standards (KCRS). An existing retaining wall north of the intersection will be moved a few feet back ( to the east) so that a minimum of 500 feet of entering sight distance (ESD) can be provided. A short two-foot keystone wall will be provided from a proposed concrete retaining wall around the intersection radius. ESD sightlines can extend over the two-foot wall. The 500 feet ofESD is the American Association of State Highway and Transportation Officials (AASHTO) minimum of the 45 MPH design speed on 156th Avenue SE (10 over posted speed limit of35 MPH). A 25-foot curb line radius is necessary because there are insufficient property rights to install the minimum 35-foot radius. The applicant has unsuccessfully made an attempt to secure the necessary ROW to construct the 35-foot radius. A power pole at the intersection will be moved 5.5 feet behind the curb line. 3. A 25-foot curb line radius was installed at the northwest corner by a recent development. The 25-foot radius was necessary due to property constraints. A road variance was processed to reduce the minimum radius from 35 feet to 25 feet. 4. A cut-retaining wall is proposed along the north side of SE 136th Street.· There will be 5.5 feet from the face of vertical curb to retaining wall along SE 136th Street but only 3 feet of clearance can be provided from the curb line to the wall at the intersection. No sidewalk is required on the north side· of SE 136th Street. The existing 5 foot paved walk along the east Variance File December 23, 2004 Page2 side of 156th Avenue SE can be maintained. A variance is requested for the clear zone that is less than 5.5 feet. 5. A variance is requested for 390 feet ofESD looking to the west from a proposed driveway on the north side of SE 136th Street at STA 4+00. A rockery along the entry to the · · driveway blocks sightlines. Staff's Findings and Conclusions: 1. Concurrence with the applicant's presentation. 2. The design of the curb return at the northeast intersection should stop the concrete curb at or prior to the half delta so that the 5-foot paved walk along the east side of 156th Avenue SE is not blocked. A pavement stripe can extend along the 25-foot radius from the end of curb to the existing edge of traveled way on 156th Avenue SE. 3. The applicant has coordinated with the property owner at the northeast corner of the intersection to move a retaining wall eastward onto the property. This will enhance sightlines for ESD. However a short wall less than two feet tall will remain at around three feet from the curb return radius. 8. ESC ANALYSIS AND DESIGN: Design of the erosion/sedimentation control plan was completed in conformance with Core Requirement #5 per the 1998 KCSWDM. Compliance with the 7 minimum requirements are summarized below. I. Clearing Limits: Clearing limits have been delineated on sheet C2.0l of the civil plans. The clearing limits extend only to those areas that will be disturbed during construction of the subject project. 2. Cover Measures: The Construction Sequence listed on sheet C2.0l of the civil plans specify specific times at which temporary and permanent cover measures will be installed. 3. Perimeter Protection: Per sheet C2.0l of the civil plans, silt fence will be used for perimeter protection. Silt fence will be installed along the perimeters of those areas that will be receiving silt-laden runoff. 4. Traffic Area Stabilization: A construction entrance will be installed. See sheets C2.0l and C2.3 l for location of construction entrance and detail. 5. Sediment Retention: The wetpond will be used for sediment retention. Sediment retention will be designed per the 1998 KCSWDM Appendix D. Surface Area: East Basin Q2 (posteast.tsf) = 1.94 cfs SA = 2080 sf/cfs * Q2 SA = 2080 sf/cfs * 1.94 cfs = 4,035 SF Available Wetpond SA (Elev. 458.5) = 120'x35'=4,200 SF> 4,035 SF=> OK Riser Diameter: The riser diameter will be 18". Emergency Overflow Spillway: The emergency overflow spillway as designed in Section 4B of this report will be installed as part of the erosion/sedimentation ponds. Dewatering Orifice: Ao= As(2h)05/(0.6*3600Tg05 ) D = 24(AJ3.14)05 Pond A0 = 4,200(2*2.0)°5/(0.6*3600*24*32.2°5 ) = 0.029 SF Pond D = 24(0.029/3.14)05 = 2.31" Use 2-3/8" ) 6. Surface Water Control: Interceptor swales will be used to direct all sediment- laden runoff to the sediment retention facility. See sheets C2.0I and C2.31 for location of swales and details. 7. Dust Control: A note on sheet C2.01 addresses the procedure for dust control should soils become too dry. Drainage Area: e-005 Hyd Method SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious Impervious Total 18.IOOOac 5.4000 ac 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 eS shallow Sheet eS 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 · 1n1v: 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 I 1.0000 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 CN Pervious 28.1000 ac 83.20 . Impervious 2.3000 ac 98.00 Total 30.4000 ac Pervious CN Data: Subbasin e-006 Perv 83.20 Impervious CN Data: Subbasin e5 Imperv 98.00 Pervious TC Data: 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 100% 1777.00 ft 2.00% Length: Slope: 0.00 ft 0.00% 0.1500 39.38 min 5.0000 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: 0.20 Intv: 10.00min TC 1.44 hrs 0.00 hrs 1.8000 ac Length: Slope: 300.00 ft 1.00% Coeff: 0.4000 Travel Time 86.31 min Drainage Area: ex_ east 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 11.1000 ac 81.80 2.10 hrs Impervious 0.5000 ac 98.00 0.17 hrs 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 10.00 min Appendix A.2. Subbasin Summary-West Basin Drainage Area: w-001 Hyd Method: SBUH Hyd Peak Factor: 484.00 Stonn 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 SCS Abs: Intv: TC 0.26 hrs 0.17hrs 2.3000 ac 0.6000 ac 0.20 10.00 min 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: SBUH Hyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area CN Pervious 14.5000 ac 86.00 Impervious 1.8000 ac 98. 00 Total 16.3000 ac Pervious CN Data: Subbasin w2 Perv Impervious CN Data: Subbasin w2 Imperv Pervious TC Data: Flow type: Description: Time Sheet None Entered Shallow None Entered Impervious TC Data: Flow type: Description: Time Fixed None Entered 86.00 98.00 Loss Method: SCS CN Number SCS Abs: Intv: TC 0.57 hrs 0.17 hrs 14.5000 ac 1.8000 ac 0.20 10.00 min Length: Slope: Coeff: Travel 300.00ft 1.70% 0.1500 31.85 min 585.00 ft 12.00% 11.0000 2.56 min Length: Slope: Coeff: Travel 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 0.17 hrs Total l.2000 ac Pervious CN Data: Subbasin w3 Perv 86.00 l.0000 ac Impervious CN Data: Subbasin w3 lmperv 98.00 0.2000 ac Pervious TC Data: Flow type: Description: Length: Slope: Coelf: Travel Time Sheet w3 sheet 300.00 ft 10.70% 0.1500 15.26min Channel w3 channel 272.00 ft 4.80% 17.0000 l.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 0.17hrs 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 ·1 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 w5 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: 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 0.17 hrs 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 0.70% 0.1500 45.42 min Shallow w6 shallow 613.00 ft 6.50"/o 11.0.000 3.64 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-007 Hyd Method: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 5.4000 ac Impervious 2.4000 ac Total 7.8000 ac Pervious CN Data: Subbasin w7 Perv Impervious CN Data: Subbasin w7 Pervious TC Data: Flow type: Description: Time Sheet w7 sheet Shallow w7 shallow Impervious TC Data: Flow type: Description: Time Fixed None Entered CN 84.50 98.00 84.50 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 1000 min TC 0.53 hrs 0.17 hrs 5.4000 ac 2.4000 ac Length: Slope: 300.00 fl 6.10% 655.00 fl . 6.10% Length: Slope: 0.00 fl 0.00% Coeff: Travel 0.2400 27.83 min 11.0000 4.02 min Coeff Travel I 0.0000 10.00 min ' Drainage Area: w-008 Hyd Method: SBUHHyd Peak Factor: 484.00 Stonn 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 0.17 hrs 9.0000ac Length: Slope: 300.00 ft 6.70% 1020.00ft 6.90% Length: Slope: Coeff: 0.4000 9.0000 Coeff Travel 40.33 min 7.19 min Travel 0.00 ft 0.00% 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 O.IOOOac 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 Loss Method: SCS CN Number SCS Abs 0.20 Intv: 10.00 min CN TC 84.00 0.38 hrs 98.00 0.17 hrs 84.00 1.8000 ac 98.00 O.IOOOac Length: Slope: Coelf: 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 Table 8.1. Hydrograph Routing -East Basin -2-Year Stonn ROUTEHYD [] THRU [Existing East] USING TYPE1A AND [2 yr] NOTZERO ACTUAL Size nVel Nel Reach Area Flow Full Q % Full nDepth CBasin / Hyd ac cts cfs ratio ft . flls 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-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-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 1 0 .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 Ell Loss Head Loss Loss Elev Rim El Fr Node To Node ft ft ft ft ft ft 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 NC129 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 , :I Table B.2. Hydrograph Routing -East Basin -10-Year Stonn ROUTEHYD U THRU [Existing East] USING TYPE1A AND [10 yr) NOTZERO ACTUAL Reach Area Flow Full a % 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 O-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 ---- 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 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 0-136 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 0-132 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- D-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 ----· D-125 92.2 20.1873 3470.27 0.01 0.4582 X-Sect 1.0267 ----- 0-124 92.2 20.03 549.84 0.04 0.4223 X-Seel 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 --- 0-121 122.6 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 -- 0-116 122.6 24.4971 27.9865 0.88 1.4271 X-Sect 5.1474 - D-115 122.6 24.4955 78.2241 0.31 1.6574 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 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 --- .. , 0-110 124.4 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 fl fl fl fl fl 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 'l-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 I ac els els. ratio ft ft/s ft/s ---------· D-Oum2 19.7 5.7736 122.33 0.05 0.5347 X-Sect 4.2649-e-001 D-Oum1 53.6 16.6641 122.33 0.14 0.9204 X-Sect 5.9522 --e-002 0-145 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 ·o.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 .4 735. 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 - 0-113 124.4 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 · June! HW Max El/ Loss Head Loss Loss Elev Rim El Fr Node To Node ft 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 ~-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 ' ·I Table 8.4. Hydrograph Routing -East Basin -SO-Year Stonn ROUTEHYD O THRU [Existing East] USING TYPE1A AND [50 yr] NOTZERO·ACTUAL nVel Nel Reach Area Flow Full Q % Full nDepth Size CBasin I Hyd ac cfs cfs ratio ft ft/s ft/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 --- 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-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 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 -100-Year Stonn ROUTEHYD [] THRU [Existing East} USING TYPE1A AND [100 yr} NOTZERO ACTUAL Nel Reach Area Flow Full Q % Full nDeplh Size nVel CBasin /Hyd ac cfs ratio ft ft/s ft/s --------- D-Dum2 19.7 7.1007 0.06 0.5932 X-Sect 4.5504 ·•·•· e-001 D-Dum1 53.6 20.334 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 1.95 -1 X-Sect 1.9538 ·-- P-117 65.2 22.46 3.41 -1 12" Diam 3.4132 8.3784 ex_east D-140 65.2 22.4518 . 0.18 0.8802 X-Sect 4.6208 -· D-139 65.2 22.4372 0.19 0.8757 X-Sect 4.9419 ·--· D-138 65.2 22.4229 0.24 1.1329 X-Sect 4. 756 ··•·• D-137 67.6 23.3927 0.08 0 .6862 X-Sect 7.4448 ·-·-e-003 P-116 67.6 23.3835 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 0-131 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 16" Diam 1.3421 13.34 0-128 92.2 31.$27 266.41 0.12 1.2034 X-Sect 6.1704 ··-· D-127 92.2 31.5932 1354.11 0.02 0.8449 X-Sect 2.6909 ·--· 0-126 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 -- 0-115 122.6 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 0-112 124.4 39.225 1134.16 0.03 0.9129 X-Sect 8.7019 •••.. ).111 124.4 39.1646 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---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 1-153 N-152 464.0445 --na--na---na-464.0445 464.17 .J-154 N-153 467.9954 --na---na---na--467.44 467.34 ' •I Table B.6. Hydrograph Routing -East Basin -Summary Table 2-Year 10-Year 25-Year SO-Year 100-Year Freeboard Free board Freetii:Jard 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 Overlop 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 Overlop Overtop D-121 N-124 N-123 Overlop 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 0-125 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 Overlop Overtop 0-128 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 Overlap 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 0-134 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 0-137 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 Overlap Overlop 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 Overlap 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 8.7. Hydrograph Routing -West Basin -2-Year Stonn ROUTEHYD O THRU [Existing West] USING TYPE1A AND [2 yr) NOTZERO ACTUAL nDepth Size nVel Nel CBasin / Hyd Reach D-021 D-020 P-016 D-019 D-018 P-015 D-017 D-016 P-014 D-015 D-014 P-013 D-012 D-011 D-010 P-012 P-011 P-010 P-009 P-008A P-008 P-007 P-006 P-005 P-004 D-009 D-008 P-003 D-007 D-006 P-002 D-005 D-004 D-003 D-002 D-001 P-001 Area Flow FullQ % Full ac cts cfs ratio 2.9 0.5767 215.99 0 2.9 0.5766 75.0242 0.01 19.2 2.8102 10.5228 0.27 19.2 2.8096 212.76 0.01 21.1 3.0333 251 .93 0.01 21.1 3.0325 7.7298 0.39 21.1 3.0318 138.18 0.02 21.1 3.0316 452.04 0.01 22.3 3.2439 7.9881 0.41 22.3 3.2432 160.64 0.02 22.3 3.2429 200 0.02 22.3 3.2423 10.6228 0.31 22.3 3.2413 290.67 0.01 22.3 3.2403 320.43 0.01 25.5 3.7564 1040.88 0 25.5 3.7551 7.0631 0.53 25.5 3.7536 6.9402 0.54 25.5 3.7521 8.217 0.46 25.5 3.7507 7.6431 0.49 27.7 4.1444 4.8684 0.85 31.5 4.8063 6.8722 0.7 31.5 4.8057 6.4104 0.75 31.5 4.8039 7.4569 0.64 39.3 6.248 9.9629 0.63 39.3 6.2406 7. 7824 0.8 39.3 6.2233 93.993 0.07 39.3 6.2231 112.96 0.06 39.3 6.2205 6.2952 0.99 39.3 6.2079 107.57 0.06 39.3 6.2077 964.56 0.01 39.3 6.204 6.1462 1.01 39.3 6.2035 --0 39.3 6.1864 44.3354 0.14 39.3 6.1853 313.41 0.02 39.3 6.1799 770.99 0.01 39.3 6.1797 146.32 0.04 48.3 6.7994 8.2043 0.83 Reh App Loss Head From Nod To Node fl ft Bend Loss ft N-002 N-003 N-004 N-005 N-001 373.6321 N-001 382.2466 -na- N-002 381.0999 -na-'- N-003 382.8899 -na- N-004 389.8769 --na- --na-- -na- --na- -na- ft 0.3321 X-Sect 0.3244 X-Sect 0.3529 12" Diam 0.6667 X-Sect 0.2382 X-Sect 0.4351 12" Diam 0.3561 X-Sect 0.254 X-Sect 0.4436 12" Diam 0.451 X-Sect 0.6317 X-Sect 0.3791 12" Diam 0. 6234 X-Sect 0.3609 X-Sect 0.5771 X-Sect 0.5186 12" Diam 0.5239 1Z' Diam 0.4742 12" Diam 0.4945 1 Z' Diam 0.709 12" Diam 0.6161 12" Diam 0.6459 12" Diam 0.5839 12" Diam 0.574 12" Diam 0.6778 12" Diam 0.6278 X-Sect 0.414 X-Sect 0.8091 12" Diam 0.5256 X-Sect 0.3936 X-Sect 0.8284 12" Diam 0.915 X-Sect 0.5256 X-Sect 0.5341 X-Sect 0.6454 X-Sect 0.4209 X-Sect 0.6946 12" Diam June! Loss ft HW Elev ft -na-- -na-- --na- --na- 380.5 380.43 382.3 389.8769 ft!s ft!s 3.0535 -- 2. 7143 ----- w-001 11.3425 13.398 w-002 4.1816 -- 5.8108 -ex_west 9.2462 9.8418 3.5277- 5.0894 - 9.6423 10.1708 w-003 3.7541 -- 4.3238 - 11.8787 13.5253 4.8101 - 4.0339 - 6.1421 --w-004 9.1309 8.9931 9.0097 8.8365 10.2249 10.4623 9.6859 9.7315 6.9597 6.1986 w-005 9.4657 8. 75 w-006 8.9569 8.162 10.0875 9.4945 13.3954 12.6852 w-007 11.0133 9.9088 2.79 ---- 6.2056 ---- 9.1373 8.0153 3.8357 ---- 8.1166 -- 8.9179 7.8256 2.1497 ---- 4.8288 --- 4.3358 --- 1.5651 - 7.1705 -- 11.6778 10.4461 w-008 Max El/ Rim El ft 380.4 380.33 382.2 390.25 .; 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.i2 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. 004 9 ------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 Stonn ROUTEHYD [] THRU [Existing West) USING TYPE1A AND [10 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd D-021 D-020 P-016 D-019 D-018 P-015 D-017 D-016 P-014 D-015 D-014 P-013 D-012 D-011 D-010 P-012 P-011 P-010 P-009 P-008A P-008 P-007 P-006 P-005 P-004 D-009 D-008 P-003 D-007 D-006 P-002 D-005 D-004 D-003 D-002 D-001 P-001 ac cfs cfs ratio ft ft/s ft/s 2.9 1.1262 215.99 0.01 0.4269 X-Sect 3.6099 ---w-001 2.9 1.126 75.0242 0.02 0.417 X-Sect 3.2085 --- 19.2 5.7252 10.5228 0.54 0.5258 12" Diam 13.6802 13.398 w-002 19.2 5.7243 212.76 0.03 0.8706 X-Sect 4.9958 ---- 21.1 6.2369 251.93 0.02 0.3597 X-Sect 7.2932 ----ex_west 21.1 6.2355 7.7298 0.81 0.6807 12" Diam 10.9508 9.8418 21.1 6.2346 138.18 0.05 0.5336 X-Sect 4.3923 - 21.1 6.2343 452.04 0.01 0.3664 X-Sect 6.4244 -- 22.3 6.6546 7.9881 0.83 0.6973 12" Diam 11.3797 10.1708 w-003 22.3 6.6534 160.64 0.04 0.6285 X-Sect 4.6707 -- 22.3 6.653 200 0.03 0.827 X-Sect 5.1746 ---- 22.3 6.652 10.6228 0.63 0.5735 12" Diam 14.2771 13.5253 22.3 6.6504 290.67 0.02 0.8162 X-Sect 5.757 -- 22.3 6.6488 320.43 0.02 0.516 X-Sect 5.0632 - 25.5 7.6794 1040.88 0.01 0.7546 X-Sect 7.3444 -w-004 25.5 7.6772 7.0631 1.09 -1 12" Diam 1.0869 8.9931 25.5 7.6747 6.9402 1.11 -1 12" Diam 1.1058 8.8365 25.5 7.6721 8.217 0.93 0.7657 12" Diam 11.8884 10.4623 25.5 7.6702 7.6431 1 0.8229 12" Diam 11.0927 9.7315 27.7 8.4447 4.8684 1.73 -1 12" Diam 1.7346 6.1986 w-005 31.5 9.6483 6.8722 1.4 -1 12" Diam 1.404 8.75 w-006 31.5 9.6459 6.4104 1.5 -112"Diam 1.5047 8.162 31.5 9.6425 7.4569 1.29 -1 12" Diam 1.2931 9.4945 39.3 12.2397 9.9629 1.23 -1 12" Diam 1.2285 12.6852 w-007 39.3 12.2337 7.7824 1.57 -1 12" Diam 1.572 9.9088 39.3 12.2305 93.993 0.13 0.867 X-Sect 3.43 -- 39.3 12.2302 112.96 0.11 0.5807 X-Sect 7.6019 --- 39.3 12.2269 6.2952 1.94 -1 12" Diam 1.9423 8.0153 39.3 12.2225 107.57 0.11 0.7439 X-Sect 4.7079 - 39.3 12.2223 964.56 0.01 0.5074 X-Sect 9.6143 -- 39.3 12.2172 6.1462 1.99 -1 12" Diam 1.9878 7.8256 39.3 12.2169 --0 0.915 X-Sect 4.2335 -- 39.3 12.207 44.3354 0.28 0.7349 X-Sect 5.8637 ---- 39.3 12.1945 313.41 0.04 0.7226 X-Sect 5.3815 - 39.3 12.1624 770.99 0.02 0.7234 X-Sect 1.7335 - 39.3 12.1621 146.32 0.08 0.5527 X-Sect 8.9201 -- 48.3 13.7386 8.2043 1.67 -1 12" Diam 1.6746 10.4461 w-008 Reh Loss App Head From Nod To Node ft ft Bend Loss ft Junct LOSS ft HW Elev fl Max El/ Rim El ft N-002 N-003 N-004 N-005 N-001 N-001 N-002 N-003 N-004 373.66 397.4953 -na- 381.0999 -na-- 382.8899 -na- 390.363 --na-- -na---na-- --na--na-- -na---na-- -na---na- 380.5 380.43 382.3 390.35 380.4 380.33 382.2 390.25 , ., 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 44 7 .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 --ila----na----na--466.8998 467.86 ·, Table 8.9. 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 D-021 D-020 ac cfs cfs ratio fl ft/s fl/s 2.9 1.4193 215.99 0.01 0.4655 X-Sect 3.8249 ---- 2.9 1.419 75.0242 0.02 0.4548 X-Sect 3.3995 --· CBasin / Hyd w-001 P-016 D-019 19.2 7.2941 10.5228 0.69 0.6125 12" Diam 14.4658 13.398 w-002 D-018 P-015 D-017 D-016 P-014 D-015 D-014 P-013 D-012 D-011 D-010 P-012 P-011 P-010 P-009 P-008A P-008 P-007 P-006 P-005 P-004 D-009 D-008 P-003 D-007 D-006 P-002 D-005 D-004 0,003 D-002 D-001 P-001 19.2 7.2903 212.76 0.03 0.9533 X-Sect 5.3071 ----- 21.1 7.9622 251.93 0.03 0.4124 X-Sect 7.8517 -----ex_west 21.1 7.9606 7.7298 1.03 0.849412" Diam 11.1952 9.8418 21.1 7.9596 138.18 0.06 0.6103 X-Sect 4.7161 -- 21.1 7.9593 452.04 0.02 0.4154 X-Sect 6.9302 ---· 22.3 8.4903 7.9881 1.06 0.8943 12" Diam 11.4571 10.1708 W"003 22.3 8.4889 160.64 0.05 0.7052 X-Sect 5.0142 ---- 22.3 8.4884 200 0.04 0.9062 X-Sect 5.4996 ----- 22.3 8.4872 10.6228 0.8 0.676 12" Diam 15.0227 13.5253 22.3 8.4854 290.67 0.03 0.8943 X-Sect 6.1186 ----- 22.3 8.4835 320.43 0.03 0.5836 X-Sect 5.4511 ---· 25.5 9.7892 1040.88 0.01 0.8265 X-Sect 7.8039 ---· w-004 25.5 9.7867 7.0631 1.39 -1 12" Diam 1.3856 8.9931 25.5 9.7842 6.9402 1.41 -1 12" Diam 1.4098 8.8365 25.5 9.7811 8.217 1.19 -1 12" Diam 1.1903 10.4623 25.5 9.7791 7.6431 1.28 -1 12" Diam 1.2795 9.7315 27.7 10.7564 4.8684 2.21 -1 12" Diam 2.2095 6.1986 w-005 31.5 12.2532 6.8722 1.78 -1 12" Diam 1.783 8.75 w-006 31.5 12.2295 6.4104 1.91 -1 12" Diam 1.9077 8.162 31.5 12.214 7.4569 1.64 -1 12" Diam 1.6379 9.4945 39.3 15.4537 9.9629 1.55 -1 12" Diam 1.5511 12.6852 w-007 39.3 15.439 7.7824 1.98 -1 12" Diam 1.9838 9.9088 39.3 15.4332 93.993 0.16 0.9703 X-Sect 3.6728 ---- 39.3 15.4329 112.96 0.14 0.6524 X-Sect 8.1307 ---- 39.3 15.4277 6.2952 2.45 -1 12" Diam 2.4507 8.0153 39.3 15.4211 107.57 0.14 0.8378 X-Sect 5.0372 --- 39.3 15.4209 964.56 0.02 0.5537 X-Sect 10.1896 ----- 39.3 15.4136 6.1462 2.51 -1 12" Diam 2.5078 7.8256 39.3 15.4133 ----0 0.915 X-Sect 5.3412 ----- 39.3 15.3973 44.3354 0.35 0.8232 X-Sect 6.2522 --- 39.3 15.3784 313.41 0.05 0.8043 X-Sect 5.7771 ----- 39.3 15.3305 770.99 0.02 0.749 X-Sect 1.8482 ---- 39.3 15.3302 146.32 0.1 0.61 X-Sect 9,5841 ---- 48.3 17.4789 8.2043 2.13 -1 12" Diam 2.1304 10.4461 w-008 Reh Bend Junct HW Max El/ Loss Loss Loss Elev Rim El From Nod To Node fl App Head fl fl fl fl fl N-001 N-002 N-001 N-003 N-002 N-004 N-003 N-005 N-004 373.66 412.2399 -na- 381.1 --na~ 382.8899 --na-- 390.6017 --na- -na---na--380.5 380.4 --na---na-380.43 380.33 -na---na--382.3 382.2 --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. 5 789 -----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 --ria----na----n.a--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 -SO-Year Storm ROUTEHYD O THRU [Existing West] USING TYPE1A AND [50 yr] NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin / Hyd 0-021 D-020 P-016 D-019 D-018 P-015 D-017 D-016 P-014 D-015 0-014 P-013 D-012 D-011 D-010 P-012 P-011 P-010 P-009 P-008A P-008 P-007 P-006 P-005 P-004 D-009 D-008 P-003 D-007 D-006 P-002 D-005 D-004 D-003 D-002 D-001 P-001 ac els els ratio ft · · · tus ft/s 2.9 1.5685 215.99 0.01 0.4833 X-Sect 3.9215 ---w-001 2.9 1.5683 75.0242 0.02 0.4722 X-Sect 3.4853 --- 19.2 8.0999 10.5228 0.77 0.6581 12" Diam 14.7787 13.398 w-002 19.2 8.0896 212.76 0.04 0.9912 X-Sect 5.4469 ----- 21.1 8.8435 251.93 0.04 0.4372 X-Sect 8.1008 ----ex_west 21.1 8.8417 7.7298 1.14 -1 12"Diam 1.1439 9.8418 21.1 8.8407 138.18 0.06 0.6463 X-Sect 4.8603 ---- 21.1 8.8404 452.04 0.02 0.4384 X-Sect 7.156 --- 22.3 9.434 7.9881 1.18 -1 12" Diam 1.181 10.1708 w-003 22.3 9.4262 160.64 0.06 0.7412 X-Sect 5.1673 ---- 22.3 9.4257 200 0.05 0.9425 X-Sect 5.6454 ----- 22.3 9.4245 10.6228 0.89 0.7329 12" Diam 15.2781 13.5253 22.3 9.4224 290.67 0.03 0.9301 X-Sect 6.2809 ---· 22.3 9.4204 320.43 0.03 0.6154 X-Sect 5.6241 --· 25.5 10.8663 1040.88 0.01 0.8595 X-Sect 8.0101 -w-004 25.5 10.8659 7.0631 1.54 -1 12" Diam 1.5384 8.9931 25.5 10.8622 6.9402 1.57 -1 12" Diam 1.5651 8.8365 25.5 10.8581 8.217 1.32 -1 12" Diam 1.3214 10.4623 25.5 10.8544 7.6431 1.42 -1 12" Diam 1.4201 9.7315 27.7 11.9326 4.8684 2.45 -1 12· Diam 2.4511 6.1986 w-005 31.5 13.5621 6,8722 1.97 -1 12" Diam 1.9735 8.75 w-006 31.5 13.5297 6.4104 2.11 -1 12" Diam 2.1106 8.162 31.5 13.5123 7.4569 1.81 -1 12"Diam 1.8121 9.4945 39.3 17.0801 9.9629 1.71 -1 12" Diam 1.7144 12.6852 w-007 39.3 17.0634 7.7824 2.19 -1 12" Diam 2.1926 9.9088 39.3 17.0568 93.993 0.18 1.0185 X-Sect 3.7809 -- 39.3 17.0564 112.96 0.15 0.6858 X-Sect 8.366 - · 39.3 17.0509 6.2952 2.71 -1 12" Diam 2.7086 8.0153 39.3 17.0435 107.57 0.16 0.8816 X-Sect 5.1838 ---·- 39.3 17.0432 964.56 0.02 0.5748 X-Sect 10.4477 -- 39.3 17.0355 6.1462 2.77 -1 12" Diam 2.7717 7.!)256 39.3 17.0353 ---0 0.915 X-Sect 5.9032 -- 39.3 17.0172 44.3354 0.38 0.8642 X-Sect 6.4254 -- 39.3 16.9961 313.41 0.05 0.8428 X-Sect 5.9539 - 39.3 16.9427 770.99 0.02 0. 7591 X-Sect 1.9232 - 39.3 16.9424 146.32 0.12 0.6369 X-Sect 9.8817 - 48.3 19.3916 8.2043 2.36 -1 12" Diam 2.3636 10.4461 w-008 Reh Bend Junct · HW Loss Loss Loss Elev From Nod To Node fl App Head fl fl fl fl Max El/ Rim El fl N-002 N-003 N-004 N-005 N-001 N-001 N-002 N-003 N-004 373.66 421.1453 -na-- 381.1 -na- 382.8899 -na-- 390.6621 --na-- -na- -na- --na- -na-- --na- --na-- --na- -na-- 380.5 380.43 382.3 390.35 380.4 380.33 382.2 390.25 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 r Table 8.11. Hydrograph Routing -West Basin -100-Year Stonn ROUTEHYD I] THRU [Existing West] USING TYPE1A AND [100 yr) NOTZERO ACTUAL Reach Area Flow Full Q % Full nDepth Size nVel Nel CBasin I Hyd D-021 D-020 P-016 D-019 D-018 P-015 D-017 D-016 P-014 D-015 D-014 P-013 D-012 D-011 D-010 P-012 P-011 P-010 P-009 P-008A P-008 P-007 P-006 P-005 P-004 D-009 D-008 P-003 D-007 D-006 P-002 D-005 D-004 D-003 D-002 D-001 P-001 ac cfs cfs ratio fl fl/s fl/s 2.9 1. 7191 215.99 0.01 0.5002 X-Sect 4.0124 --w-001 2.9 1. 7188 75.0242 0.02 0.4887 X-Sect 3.5662 - 19.2 8.9147 10.5228 0.85 0.7064 12" Diam 15.0315 13.398 w-002 19.2 8.8982 212.76 0.04 1.0272 X-Sect 5.5783 --- 21.1 9.7341 251.93 0.04 0.4611 X-Sect 8.3334 --ex_west 21.1 9.7323 7.7298 1.26 -1 12" Diam 1.2591 9.8418 21.1 9.7313 138.18 0.07 0.6809 X-Sect 4.9949 - 21.1 9.7309 452.04 0.02 0.4605 X-Sect 7.3672 - 22.3 10.3918 7.9881 1.3 -1 12" Diam 1.3009 10.1708 w-003 22.3 10.3745 160.64 0.06 0.7757 X-Sect 5.3102 - 22.3 10.3736 200 0.05 0.977 X-Sect 5.7823 - 22.3 10.3718 10.6228 0.98 0.7991 12" Diam 15.4151 13.5253 22.3 10.3694 290.67 0.04 0.9642 X-Sect 6.4331 - 22.3 10.3672 320.43 0.03 0.6459 X-Sect 5.7856 --- 25.5 11.9547 1040.88 0.01 0.8908 X-Sect 8.2036 -w-004 25.5 11.9546 7.0631 1.69 -1 12" Diam 1.6925 8.9931 25.5 11.9518 6.9402 1.72 -1 12" Diam 1.7221 8.8365 25.5 11.9391 8.217 1.45 -1 12" Diam 1.453 10.4623 25.5 11.8994 7.6431 1.56 -1 12" Diam 1.5569 9.7315 27.7 13.0768 4.8684 2.69 -1 12" Diam 2.6861 6.1986 w-005 31.5 14.8216 6.8722 2.16 -1 12" Diam 2.1567 8.75 w-006 31.5 14.7641 6.4104 2.3 -1 12" Diam 2.3031 8.162 31.5 14.7397 7.4569 1.98 -1 12" Diam 1.9766 9.4945 39.3 18.6376 9.9629 1.87 -1 12" Diam 1.8707 12.6852 w-007 39.3 18.6131 7.7824 2.39 -1 12" Diam 2.3917 9.9088 39.3 18.6037 93.993 0.2 1.0612 X-Sect 3.8828 -- 39.3 18.6034 112.96 0.16 · 0.7161 X-Sect 8.5744 -- 39.3 18.5959 6.2952 2.95 -1 12" Diam 2.954 8.0153 39.3 18.5866 107.57 0.17 0.9214 X-Sect 5.3133 --- 39.3 18.5863 964.56 0.02 0.5938 X-Sect 10.6766 ----- 39.3 18.5762 6.1462 3.02 -1 12" Diam 3.0224 7.8256 39.3 18.576 ---0 0.915 X-Sect 6.4371 ----- 39.3 18.5514 44.3354 0.42 0.9012 X-Sect 6.5778 ---- 39.3 18.5234 313.41 0.06 0.8774 X-Sect 6.1089 ---- 39.3 18.4536 770.99 0.02 0.7682 X-Sect 1.9897 -- 39.3 18.4532 146.32 0.13 0.6611 X-Sect 10.141 --- 48.3 21.1994 8.2043 2.58 -1 12" Diam 2.5839 10.4461 w-008 Reh Loss App Head From Nod To Node fl fl Bend Loss fl Jund Loss fl HW Elev fl Max El/ Rim El fl N-002 N-003 N-004 N-005 N-001 N-001 N-002 N-003 N-004 373.66 430.4121 -na-- 381.0999 -na- 382.8899 --na-- 390.6975 --na-- --na- -na-- -na- --na-- --na- --na- -na~ -na- 380.5 380.43 382.3 390.35 380.4 380.33 382.2 390.25 .·I 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---0 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 Ns032 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 fl fl fl ft fl 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 0-008 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 0-014 N-031 N-029 0.54 0.00 0.00 0.00 0.00 0-015 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 0-018 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 0-020 N-043 N-041 0.86 0.15. 0.15 0.15 0.15 D-021 N-044 N-043 1.67 0.98 0.96 0.96 0.98 .,, , Subsurface Exploratf on and Preliminary Geotechnical Engineering Report . EVENDELL PRELIMINARY PLAT. ,King County, Washington Prepared for U.S. Land Development Associates .. Pn;>ject No. KE01617A November 16, 2001 Associated Earth Sciences, Inc. November 16, 2001 Project No. KE01617A U.S. Land Development Associates c/o Centurion Development Services 226,17 8th Drive SE Bothell, Washington 98021 Attention: Mr. Mike Romano Subject: . Subsurface Exploration and Preliminary Geotechnical Engineering Report Evendell Preliminary Plat SE Renton-Issaquah Road (SR 900) and 148th Avenue SE King County, Washington Dear Mr. Rq_mano: We are pleased to present-the· enclosed copies of the above-referenced report.· This report- . summarizes the results of our subsurface exploration and geotechnical engineering study, and offers preliminary recommendations for design and development of the proposed project. We · have enjoyed working witl) you on 'this study and are confident that the reconimendations presented in this report will aid i.n a successful completion of your project. .If you should have any questions or if we can be of additional help to you; please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Bruce~· Principal Engineer BLO/da. -KE01617 Al -Projecu\2001611\KE\WP -W2K ! 91 I Fifth Avenue. Suite !00 • KirvJand. WA 98033 • Phone 425 827-770 I • Fax 425 827-5424 ,· 200 400 .:. z pww I SCALr, IN f"EtT Haozous Engineering CIVIL ENGINEERING 1'4816 SE U6TH ST, RENTON, 'wA '38059 '425-235-2707 8/12/02 "'"" .. FJM e/12;02 EVENDELL PLAT Land Use/Cover Types PROJECT NO. F1GURE 3 Pl J/ 1··. . , .. ,, 0 200 <00 M ft fi&iWiii"tlidj SCM.E IN FtET LEGEND a Co. tch Bo.sin P5 Pipe ID ltD-Yeo.r l Flooding Return Period y, ··-·.1 ,., i i. ! ,;:,.,i :·· I ,[ ,/i : .[ [!' ' ' l !' P117 ··-,~-Yeo.r l ,.. ., ., P116 12,,-Yeo.r I • P115 . ·: 12~Yecir'l . -, ,· \ PU~ 110-Yeo.r I , '· : p113f .. J2rr:Yeo.r I , , r-:G)Pf 11f-12--Y-e_o._r_j ~. 1 Plll • !10-Yeo.r j ;,'.!· .. ' ;_ .: ' ' ' ; · ... , .,:··· Haozous Engineering CIVD.. EMmu.EiWai 14816 IE 116TH ST, IIENTIIM, VA !IIIID9 U!9 l3S £)OJ OtSICN[D BY: ORA~ BY: DATE: 8/12/112 • f .• i !:: . P110; " .. ___ ... EVENDEU. PLAT Flooding Locations· PROJECT NO. rlCUl?E 4 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: SBUHHyd Peak Factor: 484.00 Storm Dur: 24.00 hrs Area Pervious 17.8000 ac Impervious 1.9000 ac 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 e I sheet Shallow e I shallow Channel e I channel Impervious TC Data: Flow type: Description: Fixed None Entered CN 85.70 98.00 85.70 98.00 Loss Method: SCS CN Number SCS Abs: 0.20 Intv: 10.00 min TC 0.98 hrs 0.17 hrs 17.8000 ac 1.9000 ac Length: Slope: 300.00 ft 1.70% 1484.00 ft 1.50% 950.00 ft I. I 0% Length: Slope: 0.00 ft 0.00% Coeff: TravelTime 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 Stonn 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 lntv: 10.00 min TC 1.01 hrs 0.17 hrs 26.9000 ac 7.0000 ac Length: Slope: 300.00 fl I. 70% 922.00 fl 1.60% 1824.00 fl 1.00% Length: Slope: 0.00 fl 0.00% Coeff: Travel Time 0.1500 31.85 min 11.0000 11.04 min 17.0000 17.88min Coeff: Travel Time I0.0000 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 0.17 hrs 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% 11.0000 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% 10.0000 10.00 min. ' ., 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: 10.00 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 0.9000ac 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: Coeff: Travel Time Fixed None Entered 0.00 ft 0.000/o 10.0000 10.00 min V Photo Number I Date of Photo: 01/05/01 Location: Existing single-family residence in north oortion of oarcel. Description: The site currently contains one single-family residence, shed, and lawn area. ~ .-. -.· .. ,. ... ::; i;1 w V Photo Number 2 Date of Photo: Location: Description: '/, I ~~ .. ,!~ "'i. ~~~~-·-~.r;;~-~·P¥::::::-~~ . .';}·-' ·"'~'''"", , • I ,,J· ~it~':t-!L \ !:-, 01/05/01 Northwest portion of parcel, looking south. Cover types on the site include mature forest, pasture, lawn, wetland, and a single-family home. Evendell Plat -Offsite Drainage System V Photo Number 3 Date of Photo: I 01/05/01 Location: Description: Location 1. in Figure 5, looking east A drainage ditch flows to the east along the north boundary of the site and turns south on the site's east boundar . ";;_':;_:CC_=c_.=~'---, -.;;;;;;;;.:::..--~---_-. V Photo Number 4 Date of Photo: Location: Description: 01/05/01 Location 8 in Figure 5, looking north. The open ditch along the east boundary of the site flows to the south along 160th A venue SE. .)·.;__: Evendell Plat -Offsite Drainage System / ..-------:::: V Photo Number 5 V Photo Number 6 Date of Photo: 01/05/01 Date of Photo: 01/05/01 Location: Location 11 in figure 5, looking south. Location: Location 33 in Figure 5, looking south. Description: After leaving the southeast corner of the site, Description: A drainage ditch flows to the south along the ditch along 160th A venue SE continues to 156th Avenue SE. The ditch has several flow to the south. . driveway and road culverts along its path. 41 Evendell Plat -Offsite Drainage System . Appendix A.2 Di:ainage Ct,gip~ainI~ Evende/1 Plat Preliminary 71R-June 2001 Table A.I. Summary of Downstream Drainage Complaints Colllplaint. ./Number . i/·.>>"· Date Property Owner Description of Complaint 89-0867 13802 1601" Avenue SE Drainage complaint not available. 95-0107 2/01/95 Steve Kohr . Broken culvert at entrance to cul-de-sac .. 15641 SE 1381h Place V 97-0206 1/10/97 Don Gregg Offsite flows impacting private property. 16046 SE l 42"d Place Backyard flooded with larger storms. Septic system operation impacted. Investigated for L/ Neighborhood Drainage Assistance Program. 97-0318 14038 561" Avenue SE Flooding due to plugged culvert. Drainage complaint is a claim and is not currently available. 97-0423 14028 160'" Avenue SE Roadside flooding -overflow of ditch along 160th Avenue SE. Drainage complaint not available. 98-0202 3/19/97 Paul Huff Drainage from neighbor impacting low area of 14312 160th Avenue SE private property. t,/ Evende/1 Plat Preliminary 11R -June 2001 :_-i · ! : I · I ·i I ' , I i ,· i >-.-·-·.·:1i ' .':L_i --~ .... , .•. _. ! .: . ' ., ·' , . . , ' . , _ _ ,_ J ! . ···1 ··,-'. '' . 1,.' ii i··,i !~ .. ·.1 I:· ' . i '· -----.--.-------- TITI.E . · . .t i. i·:·i_J! t·_..:'il ;--'. Drainage Complaints -From the Files of KCWLRD I f.' ' KlnU county Wallll' and llllid ll8suUn:8s llivlSloo , llr8lna!JII SUrvlcBS section Complalnt S8ardJ Printed: 12/28/00 7:36:58 AM " CmlqJlaint IYIII TYJJ8al ~ ·AmlrlslafProblmo -lllnls PaQB -Cmb 1914,-0095 C RIPRAP 15225 JONES RD ROCKS/DIKE/15219 JONES RD/CEDAR RIV 657A4 1974-0096 C RIPRAP 15224 JONES RD ROCK/DIKE/JONES RO/CEDAR RIVER 657A4 1974-0103 C 15631 JONES RD SE W/0 BACKFILUJONES RD 657A4 1974-0106 C DRNG 15005 JONES RD DITCH/ALONG CEDAR 657A4 197~128 C FLOG 16418 SE 145TH ST STORM SEWERS/BRIARWOOD S 65794 1976--0084 C 156TH PL SE/JONES RO DAMAGE ALONG RD/CEDAR RIVER AREA 657A4 1976-0091 C DEBRI 15463 SE JONES RD CEDAR RIVER 657A4 1979-0090 C DRNG 14406 162NOAVSE 65763 1980-0117 C DRNG 13405 158TH AVE SE 657ft2 1981-0316 C 15035 SE JONES RD DIKE JETfY/CEDAR RIVER 657A4 1982-0520 C FLOG 13612 160THAVE SE 65762 1982-0521 C FLOG 16426 SE 145TH PL BRlARWOOO AREA 65764 1963-,-0357 C DRNG 14827 SE JONES RD CHNL OVERFLO/MADSEN CRK 657A4 1983-0386 C ORNG 15243 SE 132ND ST DRNG DITCH/SE 132ND ST/152NO AVE SE 657A2 1983--0387 C FLOG 14063 171ST AVE SE BRIARWOOD AREA 65783 1984--0224 C FLOG 16211 SE 145TH ST 65784 1985--0710 E Fill 15035 SE JONES RD KG CTY NOT RESP-WlllnotENF 657A4 1986-0372 C VIOLATE 15817 SE JONES RO MOBILE HOME IN FLOOD PLAIN 657A4 1986-0372 E ILL DVLT 15817 SE JONES RD TO BALO FOR CM(CHK STAT BY CMOT). 657A4 1986-0378 C FLOG 13129 160THAVE SE BLOCKED DITCH 65782 1986--0437 C CULVERT 15252 SE 142ND PL INST ALLA TlON-NEEO CB 657A3 198e.o651 C FILLING 15045 SE JONES RD SEE 86-0745,1158 657A4 1986-0745 C Fill 15045 SE JONES RD ILLEGAL Fill-CEDAR RIVER 657A4 1986-0812 C EROSION 15421 SE JONES RO CEDAR RIVER 657A4 1986-1158 C FLOG 15059 SE JONES RD SEE: 86-0745 BRAMBLETT 86-0745 657A4 1987..()430 C TRFD TO SWM-FM/RO ORNG. 65782 1987..()430 ER OH/SWM DJV Pl Y. 65782 1987..()430 NOA OH/SWM DIV PLY. 65782 1987..()496 C DRNG 16423 SE 135TH ST SEEPAGE 65762 1987-0589 C SEE 87 -0430 WILSON. 65782 1987-0593 C DRNG 16904 SE 136TH ST DRNG ESMT WATER/DITCH NEEDS MAINT 65782 1987-1001 X FILL 16861 SE JONES RD ILLEGAL FILL IN FLOPLAlN 65784 1968-03n C DRNG 14250 161ST AVE SE HAZARDOUS PONO OHffO CM. 06/10/89 65783 1989-0020 C FILL 13400 168TH AVE SE NEAR ORNG CHNL 65782 1989-0086 C DRNG 14820 154TH PL SE INST ALLING DRAINAGE 657A4 1989-0863 C DRNG 13224 168TH AVE SE DITCH CLEANING/LOSING YARD 65782 1989-0867 Cl ORNG 13802 160TH AVE SE CL#12735 DUE APRIL 65782 Page 1 of 4 TffiE Drainage Complaints -From the.Files of KCWLRD '''°'.{' ?1'A:pp~~a:1!·.~ .. $)9rn1;ya?~f.WQ'$ysfr.mi Pesi@:,1:%·'.(Gft'i'C.•;:sYt'-'Y ',;{·/•\<'.' ... · Appendix B. l Stormwater Facility Control and Overflow Design Appendix B.2 KCRTS Pond Design Evendd/ Plat Preliminary 11R -June 2001 Evende/1 Plat Preliminary I1R-June 2001 I East Basin -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: Nwnber of orifices: Orifice * Height (ft) 1 0.00 2 5.50 3 5. 90 Top Notch Weir: Outflow Rating Curve: Hyd Inflow Outflow 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 Peak Pipe Diameter (in) 6.0 6.0 Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 3.53 1.10 7.60 459. 60 117770. 2.704 2 1. 74 0.58 7.13 459.13 107632. 2.471 3 2.09 0.50 6.65 4 58. 65 97838. 2.246 4 1. 7 4 0. 46 6.47 458.47 94092. 2.160 5 1. 84 0.21 5.72 457. 72 7 977 4. 1. 831 6 1.50 0 .11 3.30 455.30 39784. o. 913 7 1. 40 0.13 4.41 456.41 56865. 1.305 8 1. 09 0.14 5.11 4 57. 11 68 647. 1. 576 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Cale 1 1.10 0.16 ******** ******* 1.13 2 0.58 0.08 ******** ******* 0.61 3 0.50 0.09 ******** ******* 0.52 4 0.46 0.08 ******** ******* 0.47 5 0.21 0.09 ******** ******* .0. 21 6 0 .11 0.08 ******** ******* 0.18 7 0.13 0.07 ******** ******* 0.18 8 0.14 0.05 ******** ******* 0.17 Evenddl Pia/ Preliminary 11R-June 2001 West Basin -Retention/Detention Facility Type of Facility: Facility Length: Facility Width: Facility Area: Effective Storage Depth: Stage 0 Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice # Height (ft) 1 0.00 2 4.75 Top Notch Weir: Length: Weir Height: Outflow Rating Curve: Hyd Inflow Outflow Detention Vault 80.00 25.00 2000. 9.00 470.00 18000. 9.00 12.00 2 Diameter (in) 0.70 1.30 ft ft sq. ft ft ft cu. ft ft inches Full Head Discharge (CFS) 0.040 0.094 Rectangular 3.00 in 8.90 ft None Pipe Diameter (in) 4.0 Storage Peak Stage 8.96 Elev 478.96 477.61 476.91 476.00 476.07 473.11 472.40 473.97 (Cu-Ft) (Ac-Ft) 1 0.60 2 0.29 3 0.30 4 0.31 5 0.35 6 0.26 7 0.31 8 0.24 Hyd R/D Facility Outflow 1 0.15 2 0.11 3 0.10 4 0.08 5 0.09 6 0.02 7 0.02 8 0.03 0.15 0.11 0.10 0.08 0.09 0.02 0.02 0.03 Tributary Inflow 0.09 0.05 0.05 0.05 0.05 0.05 0.06 0.04 7. 61 6.91 6.00 6.07 3.11 2.40 3.97 Reservoir Inflow ******** ******** ******** ******** ******** ******** ******** ******** ---------------------------------- Route Time Series through Facility Inflow Time Series File:devwest.tsf Outflow Time Series File:rdoutw POC Time Series File:pocwest Inflow/Outflow Analysis Peak Inflow Discharge: 0.595 Peak Outflow Discharge: 0 .146 Peak Reservoir Stage: 8.96 Peak Reservoir Elev: 4 78. 96 CFS CFS Ft Ft 17921. 0.411 15219. 0.349 13815. 0.317 12009. 0.276 12133. 0.279 6214. 0.143 4797. 0.110 7942. 0.182 POC Outflow Target Cale ******* 0.20 ******* 0.14 ******* 0 .13 ******* 0 .11 ******* 0.11 ******* 0.07 ******* 0.07 ******* 0.06 at 6:00 on Jan 9 in at 11: 00 on Jan 9 in Peak Reservoir Storage: 17921. Cu-Ft o. 411 Ac-Ft Evendell Plat Preliminary 71R-Jime 200/ Year 8 Year 8 ,:·•,\pp?#if#.'¢. ··:<:~iiJ/~Y.?~!i?G~lc~I#,tjti;stl:ff'.:;;i't ;t,;tf[I/f;,;• C(,.,·.,' .''< .. Appendix C.J Stormwater System Conveyance Appendix C.2 KCRTS Time Series Calculations Appendix C.3 KCRTS Peak Flow Rates Evendell Plat Preliminary 11R-June 2001 Computing Interval Locations Computing Flow Durations Loading Time Series File:bywest.tsf Durations & Exceedence Probabilities to File:bywest.dur Evenddl Plat Preliminary 17R-June 2001 Analysis Tools Command RETURN to Previous Menu KCRTS Command eXit KCRTS Program ~ ~ €fl ~ ~ • Flow Frequency Analysis Time Series File:exeast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0. 645 2 2/09/01 18:00 0.200 7 1/05/02 16:00 0.517 3 2/28/03 3:00 0.037 8 3/24/04 19:00 0.303 6 1/05/05 8:00 0.508 4 1/18/06 20:00 0.457 5 11/24/06 4:00 0.891 l 1/09/08 9:00 Computed Peaks Flow Frequency Analysis Time Series File:exwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.138 2 2/09/01 18:00 0.059 7 1/05/02 16:00 0.129 3 2/28/03 3:00 0.024 8 8/26/04 2:00 0.074 6 1/05/05 8:00 0.122 4 1/18/06 16:00 0.116 5 11/24/06 4: 00 0.235 l 1/09/08 6:00 Computed Peaks Flow Frequency Analysis Time Series File:deveast.ts£ Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 1. 74 6 2/09/01 2:00 1. 40 8 1/05/02 16:00 2.09 3 2/27 /03 7:00 1. so 7 8/26/04 2:00 1. 80 5 10/28/04 16:00 1. 84 4 1/18/06 16:00 2.17 2 10/26/06 0:00 3.53 l 1/09/08 6:00 Computed Peaks Evendell Plat Preliminary TIR-June 2001 -----Flow Frequency Analysis------- -Peaks Rank Return Prob (CFS) Period _0.891 l 100.00 0.990 o·. 645 2 25.00 0.960 0.517 3 10.00 0.900 0.508 4 5.00 0.800 0. 457 5 3.00 0.667 0.303 6 2.00 0.500 0.200 7 1. 30 0.231 0.037 8 1.10 0.091 0.809 50.00 0.980 -----Flow Frequency Analysis------- -Peaks Rank Return Prob (CFS) Period 0.235 1 100.00 0.990 0.138 2 25.00 0.960 0.129 3 10.00 0.900 0.122 4 5.00 0.800 0.116 5 3.00 0.667 0.074 6 2.00 0.500 0.059 7 1.30 0.231 0.024 8 1.10 0.091 0.202 50.00 0.980 -----Flow Frequency Analysis------- -Peaks Rank Return Prob .(CFS) Period 3.53 1 100.00 0.990 2.17 2 25.00 o. 960 2.09 3 10.00 0.900 1. 84 4 5.00 0.800 1. 80 5 3.00 0. 667 l. 74 6 2.00 0.500 1.50 7 1. 30 0.231 l. 40 8 1.10 0.091 3.08 50.00 0.980 ( ~ ~Olf1& ~DESIGN Core Design, Inc. 14711 N.E. 29th Place Suite #101 Bellevue, Washington 98007 425.885.7877 Fax 425.885.7963 TECHNICAL INFORMATION REPORT (T.I.R.) FOR EVENDELL KING COUNTY, WASHINGTON ~J;~ft!f?Y~ ~P7f z-/-z t?/ 0 is- Prepared by: Gina R. Brooks, P.E. April 2004 Date: Revised: July 2004 Core No.: 04009 EX?IRcS 2-10-05 ,-..;u-oc::i, ENGINEER/NG PLANNING SURVEYING Flow Frequency Analysis Time Series File:devwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.294 6 2/09/01 2:00 0.240 8 1/05/02 16:00 0.354 3 2/27/03 7:00 0 .260 7 8/26/04 2 :·00 0.313 4 10/28/04 16:00 0.312 5 1/18/06 16:00 0.378 2 10/26/06 0:00 0.595 1 1/09/08 6:00 Computed Peaks Flow Frequency Analysis Time Series File:byeast.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.080 7 2/09/01 2:00 0.070 8 1/05/02 16:00 0.098 3 12/08/02 18:00 0.082 6 8/26/04 2:00 0. 097 4 10/28/04 16:00 0.085 5 1/18/06 16:00 0.120 2 10/26/06 0:00 0.156 1 1/09/08 6:00 Computed Peaks Flow Frequency Analysis Time Series File:bywest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.046 7 2/09/01 2:00 0.040 8 1/05/02 16:00 0.056 3 12/08/02 18:00 0.047 6 8/26/04 2:00 0.056 4 10/28/04 16:00 0.049 5 1/18/06 16:00 0.069 2 10/26/06 0:00 0.090 1 1/09/08 6:00 Computed Peaks Evenddl Plat Preliminary ITR-June 2001 -----Flow Frequency Analysis------- -Peaks Rank Return Prob (CFS) Period 0.595 1 100.00 0.990 0.378 2 25.00 0.960 0.354 3 10.00 0.900 0. 313 4 5.00 0. 80.0 0.312 5 3.00 0.667 0. 294 6 2.00 0.500 0. 260 7 1. 30 0.231 0.240 8 1.10 0.091 0.523 50.00 0.980 -----Flow Frequency Analysis--~---- -Peaks Rank Return Prob (CFS) Period 0.156 1 100.00 0.990 0.120 2 25.00 o. 960 0.098 3 10.00 0.900 0. 097 4 5.00 0.800 0.085 5 3.00 0. 667 0.082 6 2.00 0.500 0.080 7 1. 30 0.231 0.070 8 1.10 0.091 0.144 50.00 0.980 -----Flow Frequency Analysis------- -Peaks Rank Return Prob (CFS) Period 0.090 1 100.00 0.990 0.069 2 25.00 o. 960 0.056 3 10.00 0.900 0.056 4 5.00 0.800 0.049 .5 3.00 0.667 0.047 6 2.00 0.500 0.046 7 1.30 0.231 0.040 8 1.10 0.091 o .. 083 50.00 0.980 ' D Flow Frequency Analysis • Time Series File:poceast.tsf Project Location:Sea-Tac D ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period o. 611 2 2/09/01 19:00 1.13 1 100.00 0.990 0.177 7 1/05/02 16:00 0. 611 2 25.00 o. 960 0.517 3 3/06/03 20:00 o. 517 3 10.00 0.900 0.182 6 8/26/04 2:00 0.472 4 5.00 0.800 p 0.173 8 1/05/05 8:00 0.214 5 3.00 0.667 0.214 5 1/19/06 2:00 0.182 6 2.00 0.500 0. 472 4 11/24/06 6 :.00 0.177 7 1. 30 0.231 1.13 1 1/09/08 11 :00 0.173 8 1.10 0.091 Computed Peaks 0.955 50.00 0.980 1. Flow Frequency Analysis Time Series File:pocwest.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis~------ Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.140 2 2/09/01 18:00 0.197 1 100.00 0 .. 990 0.059 8 1/05/02 16: 00 0 .140 2 25.00 0.960 ' 0.110 4 3/06/03 19: 00 0.135 3 10.00 0.900 0. 067 7 8/26/04 2:00 0.110 4 5.00 0. 800 0. 068 6 10/28/04 16: 00 0.107 5 3.00 0.667 0.107 5 1/18/06 20:00 0. 068 6 2.00 0.500 0.135 3 11/24/06 4:00 0.067 7 1. 30 0.231 0.197 1 1/09/08 9:00 0.059 8 1.10 0.091 Computed Peaks 0.178 50.00 0.980 '. Evendell Plat Preliminary 71R-June 2001 b , • The following is a description of KCRTS input and output files used in designing the R/D facilities and conducting the downstream drainage analysis for the Evendell Plat. EXECUTABLE FILES basins.exc: This executable file creates time series for all contributing areas to J the downstream system . . tar.exc: This executable creates target duration files for R/D design. TIME SERIES FILES RID Design exeast.tsf: The site's easterly basin under existing conditions. Includes area of proposed road improvements along SE 136th Street. exwest.tsf: The site's westerly basin under existing conditions. Includes area of proposed road improvements along SE 136th Street. byeast.tsf: The portion of proposed road improvements along SE 136th Street in the easterly basin that bypasses the stormwater facility. bywest.tsf: The portion of proposed road improvements along SE 136th Street in the westerly basin that bypasses the stormwater facility. deveast.tsf: The site's easterly basin under proposed developed conditions. , Includes area of proposed road improvements along SE 136th Street. • devwest.tsf: The site's westerly basin under proposed developed conditions. Includes area of proposed road improvements along SE 136th Street. poceast.tsf: Time series for developed conditions at the site's easterly downstream point-of-compliance. pocwest.tsf: Time series for developed conditions at the site's westerly downstream point-of-compliance. Evendell Plat Preliminary JIR-June 2001 tare.tsf: Target duration easterly basin. tarw.tsf: Target duration westerly basin. RESERVOIRS rdeas.rdf: curve for the Based on the curve for the Based on the proposed R/D system for the site's following times series: exeast.tsf. proposed R/D system for the site's following times series: exwest.tsf. The Evendell Plat R/D facility managing stormwater from the easterly basin of the developed site, including an offsite road improvements. rdwes.rdf: The Evendell Plat R/D facility managing stormwater from the westerly basin of the developed site, including an offsite road improvements. GENERAL NOTES 1. Seatac regional rainfall runoff files with a scale factor of 1.0 were used in the hydrologic simulations. 2. R/D facilities were d_esigned with the 8-year data set. 1-hour peak flow rates were used for detention calculations. 3. 15-minute peak flow rates were used for conveyance calculations. 4. Gravel areas were modeled in KCRTS by assuming that 50 percent of the area is impervious and the remaining 50 percent are the same cover type as that surrounding the gravel area. ' Evendell Plat Preliminary 11R-June 2001 ~ ~ Evendell Plat Level 3 Downstream Drainage Analysis !EXPIRES: Submilled 10: King County DOES 900 0.akesdale A venue S. W. Renton, WA 98055 Prepared by: Haozous Engineering, P.S. 9957 171'1 Avenue SE Renton, WA 98059 Tel. (425) 235-2707 Fax (425) 254-0579 :August 26, 2002 ,•,; -~ ., " " /Engin@@rlng. 9957 17 r1 Avenue SE fa:x (./25/ 25./-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 DOES File No. Dear Mr. Romano: I!'. s. This 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 1361h Street are also proposed. Level 2 RID standards are being proposed for the onsite storm water 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, l 999). The site is located east of 1561h A venue 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 A venue 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, l 990). ., 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 13814 160th Avenue 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 I 60'h A venue SE and 1561h Avenue SE. The conveyance system along 1601h 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. 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 Stormshed™ 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'; e~terly 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 un/ts per acre. Land uses and cover types are shown in Figure 3. 11]1~_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 Alderwood 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 JOO-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-, JO-, 25-, 50-, and I 00-year storms design storms in the SBUH model. Modeling Results Details of each subbasin modeled in Stormshed are presented in Appendix A.1 for the easterly basin and in Appendix A.2 for the westerly basin. Model results for routing the design storm hydro graphs through the drainage networks are presented in Tables B. l 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 1601h A venue SE flood at a return period of2-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 B.12 and Figure 4 ). Conclusions Several flooding locations with return periods of 2°years were identified in the downstream conveyance systems. Flooding in the east basin that overtops and.inundates · I 60'h A venue SE is considered a severe road flooding problem by the King County 3 Surface Water Drainage Manual. Residential structures have been flooded at 14028 160th A venue SE and at 16046 SE 142•• 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 fr.om 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 Suiface Water Drainage Marnia/ (1998). We found no documentation indicating that 1561h 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 200 l ). · 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 1601h 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 1601h Avenue SE to eliminate road flooding. This would likely entail replacing driveway culverts P-117 and Ps 116 on the west side of 1601h Avenue SE, cross culvert P-115, and pipesP-114 ~nd P-113 on the east side of 1601h Avenue SE (Figure 4). For the severe erosion problem along the east boundary of the property at 16046 SE 142.a 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 Suiface 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 !fyou 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 ; .. , References Haozous Engineering, June 15, 200 I. Evendell Plat -Preliminary Technical Information Report. Renton, Wash. King County Department ofNatural Resources, 1998. King County Surface Water Design Manual. Seattle. King County Department of Natural Resources, 1997. Lower 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 ( continued) Reach ID Reach Pipe Dia. Manning's Length Upstr IE DwnstlE Slope Type (JN) n _(FT} (FT) (Ff} {%} 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 45f33 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 1ill-forest Till-pasture (AG (AG -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 Jmperv (AC} (AC) (AG 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. I 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 I .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 . l Table 4. Curve Numbers for Subbasius Subbasin Pervious Pen•ious lmpen• CN (AG (AG East Basin el 85.7 I 7.8 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.l 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 -· Travel Path Distances and Slopes for Pervious Land Areas Sheet Flow Delta Shallow Flow Delta· Channel Flow Delta Subbasin. Distance Elev. Slope Distance Elev. Slope Distance Elev. Slope (FI) (FI) (FT/FI) (FI) (FI) (FT/FI) (FI) (FI) (FT/FI) 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 J.O 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 0.100 322.0 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 I. Sumary of Surveyed Structures in Downstream System Reach ID Reach Pipe Dia. Manning's Length Upstr IE DwnstJE Slope Type (IN) n (FT). (FT) (FT) (%) East Basin D-1 JO X-Scction 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-Scction 0.035 12 411.86 411.25 5.28 D-114 X-Section 0.035 48 412.96 411.86 2.31 C.P:llO: 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 33 415.1 414.27 2.48 D-117 X-Section 0.035 24 415.34 415.l 1.01 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 1p:1 I J <::ircular 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 b-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 cr.:.111· ;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_,+lA, ,Circular · 24 0.024 21 439.59 439.l 2.37 D-132 X-Section 0.035 10 440.26 439.59 7.02 P=H5:? ',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 .r;l:16.:::, Circular <::)8 0.024 ,J8 . 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 ·-· .. (12 0.013 (18 · 452.9 •P-1.11, (Circular 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 JOO 466.72 462.79 3.92 .I 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 IO 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 13.1 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 using the SBUH method. 9i . -·, .. ~... . .. . . : .. -. : _; ·\. \ 'I : ::, SOURCE: USGS 7.5 x 15 Minute Series -Renton, Washington SCALE: 1 :25 000 TfilE Figure 1. Vicinity Map PAGE DATE 1-5 01/03/01 .. i_ .• C::0(1 4DO f:WM!i#ii\ m:: SCAl.£ IN F't£T td , ...... /f \':' \ \ \ia } , / u ! i ·, \ i.l ~ I ~ii/; \ )J ~1: lj ~ \ ·~ It IU \I! -~ : .d' \ ~ii ' .,\ uJ'' >!1 ·,,4:l \.'! \\ i=' ,. illl \ ~fi \'j'l. ;J1 t!,'. 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OF/, :Y-RTRl fT p;Qy \IARf° A • " \,\;,,:,)·::<. \ ' SITE IS St. OF TRIBUTARY AREA' '·-s:···· ,,, ··-.~,.•,.,o··-),,,, ... • Haozous Engineering CIVIL ENG~NG U816 SE U6TH ST, RENTON, VA ,eo::;, -235-2707 -·· . .,., .... 8/12/02 ...... .,, "'"' EJM 8/12/02 !i :· ,·,:? .. 1." ··,., 'ii\'" ·-,1,r,:~'\:t\f, e6· -'1 \ r1 .. , ~ .,..,.,-1 r .... .,, \ ,., ~~---~--~. L:~-~~>,:w,, .. ,.,, '"•,-.,., SITE IS 9% OF TRIBUTARY AREA PROJECT NO. EVENDELL PLAT. FlCURE Drainage Basins 2 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT: The bond quantities worksheet and facility summaries will be completed upon engineering plan approval. A Declaration of Covenant will be completed prior to engineering plan approval. Site Improvement Bond Quantity Worksheet @ King County Department of Development & Environmental Services 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 206-296-6600 TTY 206-296-7217 Project Name: Plat of Evendell Location: SE 136th St & 157th Ave SE Clearing greater than or equal to 5,000 board feet of timber? X yes If yes, Forest Practice Permit Number: (RCW76.09) Page 1 of 9 no L04GF042 For alternate formats, call 206-296-6600. Date: 10-Nov-04 Project No.: · L-0 / P 0-0 Lb Activity No.: Ul I f'tltl 16Afl83RE838 Lo4-~R oz.f Note: All prices include labor, equipment, materials, overhead and profit Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. R~n,.b.dd r tlffY~ ~/Y7 t1/3o/z.w1 04009BQW03.xls Check out the DOES Web site at www.metrokc.gov/ddes Unit prices updated: 02/12/02 Version: 04122/02 Report Date: 11/30/2004 Site Improvement Bond Quantity Worksheet EROSIONlS!tDIMENT eoNmeofilt}·•:•}·············· Backfill & compaction-embankment Check dams, 4" minus rock Crushed surfacing 1 1 /4" minus Ditching Excavation-bulk Fence, silt Fence, Temporarv (NGPE) . Hydroseeding Jute Mesh Mulch, by hand, straw, 3" deep Mulch, by machine, straw, 2" deep Piping, temporarv, CPP, 6" Piping, temporary, CPP, 8" Piping, temporary, CPP, 12" Plastic covering, 6mm thick, sandbagged Rip Rap, machine placed; slopes Rock Ccnstruction Entrance, 50'x15'x1' Rock Ccnstruction Entrance, 100'x15'x1' Sediment pond riser assembly Sediment trap, 5' high berm Sed. trap, 5' high, riprapped spillway berm section Seeding, by hand Sodding, 1" deep, level ground Sodding, 1" deep, sloped ground TESC Supervisor Water truck, dust control WRtTE.YNdl'EMSr!Miii Concrete Vault Page 2 of 9 04009BOW03.xls ESC-1 ESC-2 SWDM 5.4.6.3 ESC-3 WSDOT 9-03.9(3) ESC-4 ESC-5 ESC-6 SWDM 5.4.3.1 ESC-7 ESC-8 SWDM 5.4.2.4 ESC-9 SWDM 5.4.2.2 ESC-10 SWDM 5.4.2.1 ESC-11 SWDM 5.4.2.1 ESC-12 ESC-13 ESC-14 . ESC-15 SWDM 5.4.2.3 ESC-16 WSDOT 9-13.1(2) ESC-17 SWDM 5.4.4.1 ESC-18 SWDM 5.4.4.1 ESC-19 SWDM 5.4.5.2 ESC-20 SWDM 5.4.5.1 ESC-21 SWDM 5.4.5.1 ESC-22 SWDM 5.4.2.4 ESC-23 SWDM 5.4.2.5 ESC-24 SWDM 5.4.2.5 ESC-25 ESC-26 SWDM 5.4.7 I $ 5.62 CY-1 1500o) $ 67.51 Each I 161 $ 85.45 CY $ 8.08 CY 275 $ 1.50 CY 15000 $ 1.38 LF 2400 $ 1.38 LF $ 0.59 SY $ 1.45 SY $ 2.01 SY $ 0.53 SY I 500001 $ 10.70 LF $ 16.10 LF $ 20.70 LF I 2001 $ 2.30 SY $ 39.08 CY I 51 $ 1,464.34 Each $ 2,928.68 Each 1 $ 1,949.38 Each I 1 I $ 17.91 LF $ 68.54 LF $ 0.51 SY $ 6.03 SY $ 7.45 SY $ 74.75 HR I 101 $ I $120.000.00 1 Each 1 1 I ESC SUBTOTAL:· 30% CONTINGENCY & MOBILIZATI.ON: ESCTOTAL: COLUMN: Check out the DDES Web site at www.metrokc.gov/ddes -----·-- 11 84300 11 1080 1 2222 1 22500 1 3312 11 26500 11 4140 11 195 --11 --2929 1 I 1 1 I 1949 120000 $ 270,852.62 $ 81,255.79 $ 352,108.41 A Unit prices updated: 02/12/02 Version: 04/22/02 Report Date: 11/30/2004 v Site Improvement B .d Quantity Worksheet Backfill & Compaction-embankment GI· 1 $ 5.62 Backfill & Compaction-trench GI -2 $ 8.53 Clear/Remove Brush, by hand GI -3 $ 0.36 Clearing/Grubbing/Tree Removal GI -4 $ 8,876.16 Excavation -bulk GI -5 $ 1.50 Excavation -Trench GI -6 $ 4.06 Fencing, cedar, 6' high GI -7 $ 18.55 Fencing, chain link, vinyl coated, 6' hig GI -8 $ 13.44 Fencing, chain link, gate, vinyl coated, 2 GI -9 $ 1,271.81 Fencing, split rail, 3' high GI -1 $ 12.12 Fill & compact -common barrow GI -11 $ 22.57 Fill & compact -gravel base GI -1, $ 25.48 Fill & compact -screened topsoil GI -1· $ 37.85 Gabion, 12" deep, stone filled mesh GI -1, $ 54.31 Gabion, 18" deep, stone filled mesh GI -1 $ 74.85 Gabion, 36" deeo, stone filled mesh GI -1E $ 132.48 Grading, fine, by hand GI -11 $ 2.02 Grading, fine, with grader GI -1E $ 0.95 Monuments, 3' long GI -1! $ 135.13 !Sensitive Areas Sign GI -20 $ 2.88 Sodding, 1" deep, sloped ground GI -21 $ 7.46 Surveying, line & grade GI -2 $ 788.26 Surveying, lot location/lines GI -2'. $ 1,556.64 Traffic control crew ( 2 flaggers) GI -24 $ 85.18 Trail, 4N chipped wood GI -2! $ 7.59 Trail, 4" crushed cinder GI -2 $ 8.33 Trail, 4" top course GI -2 $ 8.19 Wall, retaining, concrete GI -21 $ 44.16 Wall, rockery GI -2! $ 9.49 Page 3 of9 SUBTOTAL ·KCC 27 A authorizes only one bond reduction. 04009BQW03.xls CY I I I 20001 11,240.001 150001 84,300.00 CY j 35oj 2,985.5~ 600j _5,118.ool 10501 8,956.50 SY Acre 2 17,752.32 2 17,75232L _9_L__ 79,885.44 ------ CY 5750 8,625.00' CY 400 __ 1,624.00 --·--650 ____ 2c639ool 11501 4,669.00 LF LF Each LF CY CY CY SY SY SY SY SY Each I 51 675.651 121 _1,621.56 Each SY Day I i I 788.261 21 1,576.521 1 I 788.26 Acre HR SY SY SY SF 1 2,5ool 110,400.00 SF 1125 10,676.251 -- 144,901.98 ___1tl,ij72.40 178,599.20 Check out the DDES Web site atwww.metrokc.gov/ddes Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 11/30/2004 Site Improvement 6, ..,.d Quantity Worksheet . . RoA61MPRovsMENT >·••••t•· AC Grinding, 4' wide machine < 1 OOOs\ AC Grindi/1g, 4' wide machine 1 ooo-2ood RI -2 $ 5.75 AC Grinding, 4' wide machine> 2000sJ RI -3 $ 1.38 Rl-4 $ 41.14 Barricade, tvpe I RI -5 $ 30.03 Barricade, tvpe Ill ( Permanent ) Rl-6 $ 45.05 Curb & Gutter, rolled RI -7 $ 13.27 Curb & Gutter, vertical Rl-8 $. 9.69 Curb and Gutter, demolition and dispos Rl-9 $ 13.58 Curb, extruded asphalt Rl-10 $ 2.44 Curb; extruded concrete RI -11 $ 2.56 Sawcut, asphalt, 3" deoth RI -1: $ 1.85 Sawcut, concrete, oer 1" depth RI -1· $ 1.69 Sealant, asphalt RI -14 $ 0.99 $ - Shoulder, gravel, 4" thick RI -1E $ 7.53 Sidewalk, 4" thick RI -1 $ 30.52 Sidewalk, 4" thick, demolitloh and disno~ RI -11 $ 27.73 Sidewalk, 5" thick RI ·H $ 34.94 Sidewalk, 5" thick, demolition and disnnc:: RI -20 $ 34.65 Sign, handiCap . RI -21 $ 85.28 Striping, per stall RI -2, $ 5.82 Striping, thermoplastic, ( for crosswalk Rl-23 $ 2.38 Striping, 4" reflectorized line RI -2' $ 0.25 Page 4 of9 SUBTOTAL *KCC 27A authorizes only one bond reduction. . 04009B0W03.xls \);®*itr\i\il,~(tI" SY SY SY LF LF LF 1 1 1 3300j _4_3,791.00 LF l 2sooJ _ 24,22s.ool LF LF LF LF LF LF SY SY SY I 11001 33,s72.ool 9251 28,231.00 SY SY SY Each Each SF I 120T 285.601 I I sol LF I 56001 1,400.001 59,482.60 72,022.00 Check out the DDES Web site at www_metrokc.gov!c/des -~.-! 119.00 119.00 Unit prices updated• 02/12/02 Version• 4/22/02 Report Date: 11/30/2004 Site Improvement E Jd Quantity Worksheet For KCRS '93, (additional 2.5" base) add RS -1 $ 3.60 AC Overtay, 1.5" AC RS -2 $ 7.39 AC Overlay, 2" AC RS -3 $ 8.75 AC Road, 2", 4" rock, First 2500 SY RS -4 $ 17.24 AC Road, 2", 4" rock, Qty. over 2500S RS -5 $ 13.36 AC Road, 3", 4" rock, First 2500 SY RS-6 $ 19.69 AC Road, 3", 4" rock, Qtv. over 2500 S 'RS -7 $ 15.81 AC Road, 5", First 2500 SY RS -8 $ 14.57 AC Road, 5", Qty. Over 2500 SY RS-9 $ 13.94 AC Road, 6", First 2500 SY RS-1 $ 16.76 AC Road, 6", Qtv. Over 2500 SY RS -1 1 $ 16.12 Asphalt Treated Base, 4" thick <S -1 $ 9.21 $ 11.41 $ 7.53 $ 21.51 PCC Road, 6", no base, over 2500 SY IRs -16 $ 21.87 Thickened Edge . IRS-1~$ 6.89 Page 5 of9 SUBTOTAL ·KCC 27 A authorizes only one bond reduction. 04009BQW03.xls \\\( r:r~ffii!llii\f SY I 35001 -12.600.001 27701 9,912.001 14501 SY SY SY 25oof 43,100.001 14501 - SY 27oJ. ___ 3,607.20j SY 2500 49,225.00 SY 1000 15,810.00 SY SY SY SY SY SY SY SY SY LF 1 1 l T T 6401 77,635.00 56,67_9.20 Check out the DDES Web site at www.metrokc.gov/ddes 5,220.00 _ 24,998.00 4,409.60 34,627.60 Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 11/30/2004 Site Improvement E Jd Quantity Worksheet lliRAfflAGE\ !@e!l@@-!~i!\AA\i#!ll/iiii!!/14/l!s\i\!!$i/MliW t IIi!J ifoi¢M&rt~~;:4J@~i!;iiiiii~¥i0Ji,lii~ii~~iiii.wiiivC!ii~i~,k~~~ii,li~~\iiiifa Access Road, R/D. I D -1 I $ 16.74 I SY Bollards -fixed I D-21 $ 240. 74 I Each Bollards -removable I D-3 I $ 452.34 j Each 2 481.481 I 452.34: * (CBs include frame and lid) CB T\/ne I D-4 $ 1,257.64 Each 12 15,091.68 22 27,668.08 CB Type IL D-5 $ 1,433.59 Each CB Type 11, 48" diameter D-6 $ 2,033.57 Each 8 16,268.56 9 18,302.13 for additional depth over 4' D-7 $ 436.52 FT 29 12,659.08 9 3,928.68 CB Type II, 54" dii3.meter D-8 $ 2,192.54 Each for additional depth over 4' D-9 $ 486.53 FT CB Type IJ, 60" diameter D-10 $ 2,351.52 Each 1 2,351.52 for additional depth over 4' D -11 $ 536.54 FT 536.54 CB Tvne II, 72" diameter D-12 $ 3,212.64 Each -- for additional depth over 4' D-13 $ 692.21 FT -- Through-curb Inlet Framework (Add) D-14 $ 366.09 Each 3 1,098.27 Cleanout, PVC, 4" D-15 $ 130.55 Each . Cleanout, PVC, 6" D-16 $ 174.90 Each Cleanout, PVC, 8" D-17 $ 224.19 Each Culvert, PVC, 4" D-18 $ 8.64 LF Culvert, PVC, 6" D-19 $ 12.60 LF Culvert, PVC, 8" D-20 $ 13.33 LF Culvert, PVC, 12" D-21 $ 21.77 LF Culvert, CMP, 8" D-22 $ 17.25 LF Culvert, CMP, 12" D-23 $ 26.45 LF Culvert, CMP, 15 .. D-24 $ 32.73 u Culvert, CMP, 18" D-25 $ 37.74 LF Culvert, CMP, 24" D-26 $ 53.33 LF Culvert. CMP, 30" D-27 $ 71.45 LF Culvert, CMP, 36" D-28 $ 112.11 LF Culvert, CMP, 48" D -29 $ 140.83 LF Culvert, CMP, 60" D-30 $ 235.45 LF ;culvert, CMP, 72" D-31 $ 302.58 LF Page 6 of9 SUBTOTAL 46,587.95 52,250.41 ... KCC 27A authorizes only one bond reduction. 04009BOW03.xls Check out the DDES Web site at www_metrokc.qovlddes I 2 2 11 3 17 . 53 481.48 904.68 13,834.04 6,100.71 7,420.84 2,351.52 9,269.70 40,362.97 Unit prices updated: 02/12/02 Version: 4/22/02 Report Dale: 11/30/2004 ' Site Improvement [ )d Quantity Worksheet ICulvert, Concrete, 8" D • 32 $ 21.02 Culvert, Concrete, 12" D-33 $ 30.05 Culvert, Concrete, 15" D • 34 $ 37.34 Culvert, Concrete, 18" D-35 $ 44.51 Culvert, Concrete, 24" D · 36 $ 61.07 Culvert, Concrete, 30" D • 37 $ 104.18 Culvert, Concrete, 36" D • 38 $ 137.63 Culvert, Concrete, 42" D • 39 $ 158.42 Culvert, Concrete, 48" D-40 $ 175.94 Culvert, CPP, 6"' D • 41 $ 10.70 Culvert, CPP, 8" D-42 $ 16.10 Culvert, CPP, 12" D • 43 $ 20.70 Culvert, CPP, 15" D-44 $ 23.00 Culvert, CPP, 18" D -45 $ 27.60 Culvert, CPP, 24" D. 46 $ 36.80 Culvert, CPP, 30" D-47 $ 48.30 Culvert, CPP, 36" D-48 $ 55.20 Ditching D-49 $ 8.08 Flow Dispersal Trench (1,436 base+) D • 50 $ 25.99 French Drain (3' depth) D • 51 $ 22.60 Geotextile, laid in trench, polypropylene D.· 52 $ 2.40 D. 53 $ 74.75 Mid-tank Access Riser, 48" dia, S dee1 D • 54 $ 1,605.40 Pond Overflow Spillwav D • 55 $ 14.01 Restrictor/Oil Separator, 12" D · 56 $ 1,045.19 Restrictor/Oil Separator, 15" D • 57 $ 1,095.56 Restrictor/Oil Separator, 18" D-58 $ 1,146.16 Riprao, placed D • 59 $ 39.08 Tank End Reducer (36" diameter) D-60 $ 1,000.50 Trash Rack, 12"' D-61 $ 211.97 Trash Rack, 15" D-62 $ 237.27 Trash Rack, 18" D-63 $ 268.89 'Trash Rack, 21" D· 64 $ 306.84 Page 7 of9 SUBTOTAL ·KCC 27 A authorizes only one bond reduction. 04009BQW03.xls LF LF LF LF LF LF LF LF LF LF 2700 LF LF 1 s1sl 10722.61 2181 45146.7 935 LF I sol 11 soj 73 1679 LF 165 LF I 5891 21675.2 LF LF CY I sol 404 LF LF SY HR Each SY 50 Each Each Each CY Each Each Each Each Each 33951.8 46825.7 Check out the ODES Web site at wwwmetrokc.qov!ddes _; 28890 19354.5 4554 700.5 1146.16 268.89 54914.05 Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 11/30/2004 \ Site Improvement E. Jd Quantity Worksheet No. Z' AC, 2" top course rock & 4" borrow PL -1 $ 15.84 SY 2" AC, 1.5" top course & 2.5" base cour PL -2 $ 17.24 SY 4" select borrow PL -3 $ 4.55 SY 1.5" to.e_ course rock & 2.5" base coursE PL -4 $ 11.41 .SY Wl-1 Each Con-crete Sidewalk Wl-2 $ 30.52 SY 140 4272.8 500 15.260.ool Grading Wl-3 .$ 5,000.00 LS 1 5,000.00 Concrete Stairs Wl-4 $ 5,000.00 LS I Metal Handrail Wl-5 $ 50.00 FT ---~ I Wl-6 Wl-7 Wl-8 Wl-9 \-\1-10 SUBTOTAL 4,272.80 20.260.00 SUBTOTAL (SUM ALL PAGES): 366,832.13 v' 296,609.71 / 30% CONTINGENCY & MOBILIZATION: 110,049.64 88,982.91 GRANDTOTAL: 476,881.77 • 385,592.62 _,, COLUMN: B C Page 8 of 9 "KCC 27A authorizes only one bond reduction. 04009BQW03.xls Check out the DDES Web site at www.metrokc.gov/ddes soJ 11 sol _/ 1,526.00 5,000.00 3,000.00 9,526.00 318,148.82 ./ 95,444.65 413,593.47 ,/ D E Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 11/30/2004 ' ·-' _, Site Improvement Bond Quantity Worksheet Original bond computations prepared by: Name: Plat of Evendell Date: 1 O-Nov-04 PE Registration Number: 33713 Tel. #: 425-885-7877 Firm Name: Address: Core Desill_n, Inc. 14711 NE 29th Place, Suite #101 Project No: LO/foolb ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS Stabilization/Erosion Sediment Control (ESC) Existing Right-of-Way Improvements PERFORMANCE BOND• AMOUNT (A) $ 352,108.4 · (8) $ 476,881.8 Future Public Road Improvements & Drainage Facilities (C) $ 385,592.6 Private Improvements (0) $ 413,593.5 Calculated Quantity Completed Total Right-of Way and/or Site Restoration Bond*r' (First $7,500 of bond• shall be cash.) Perfonmance Bond• Amount (A+B+C+D) =. TOTAL Reduced Performance Bond• Total *** Maintenance/Defect Bond• Total NAME OF PERSON PREPARING BOND• REDUCTION: (A+B) $ 828,990.2 (T) $ 1,628,176.3 Minimum bond" amount 1s $1000. BOND· AMOUNT REQUIRED AT RECORDING OR TEMPORARY OCCUPANCY••• (E) _;Se,..._~~~~~ T x0.30 $ 488,452.9 OR (T-E) $ 1,628,176.3 Use larger of Tx30% or (T~E) Date: * NOTE: The word •bond· as used in this document means any financial guarantee acceptable to King County . .. NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. PUBLIC ROAD & DRAINAGE MAINTENANCE/DEFECT BOND· (B+C) X 0.25 = $ 215,618.6 The iestoration requirement shall indude the totat cost for all TESC as a minimum, not a maximum. In addition, corrective work, both on-and off-site needs to be induded. Quantities shall reflect worse case scenarios not just minimum requirements. For example, If a salmonld stream may be damaged, some ·estimated costs for restoration needs to be reflected In this amount The 30% contingency and mobilization costs are computed in this quantity . ... NOTE: Per KCC 27A, total bond amounts remainln9 after reduction shall not be lesS than 30% of the original amount (T) or as revised by ITlajor design changes. SURETY BOND RIDER NOTE: If a bond rider is used, minimum additional performance bond shall be I $ 799,186.1 !(C+D}-E REQUIRED BOND• AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DOES Page 9 of 9 04009BQW03.xls Check out the ODES Web site at www.metrokc.gov/ddes Unit prices updated: 02/12/02 Version: 4/22/02 Report Date: 11/30/2004 SUBSURFACE EXPLORATION AND· PRELIMINARY GEOTECHNICAL ENGINEERING REPORT EVENDELL PRELIMINARY PLAT ,,. King County, Washington Prepared for: U.S. Land Development Associates c/o Centurion Development Services 22617 8"' Drive SE Bothell, Washington 98021 Prepared by: Associated Earth Sciences, Inc. 911 5"' Avenue, Suite 100 Kirkland, Washington 98033 425-827-7701 Fax: 425-827-5424 November 16, 2001 Project No. KE01617A Evende/1 Preliminary Plar King County, Washington Subsuiface Exploration and Preliminary Geotechnical Engineering Repon Project and Site Conditions I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION This report presents the results of our subsurface exploration and preliminary geotechnical engineering study for the proposed Evendell Preliminary Plat located at the intersection of SE 136th Street and 160th Avenue SE in King County, Washington (Figure I). The approximate locations of the explorations completed for this study are presented on the Site and Exploration Plan, Figure 2. 1.1 Purpose and Scope The purpose of this study was to provide subsurface data to be used in the preliminary design and development of the above-mentioned project. Our study included reviewing available geologic literature, excavating exploration pits, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface soils and shallow ground water conditions. Geotechnical engineering studies were also conducted to determine the type of suitable foundation, allowable bearing pressures, anticipated settlements, floor support recommendations, and drainage considerations. This report summarizes our current fieldwork and offers development recommendations based on our present understanding of the project. 1.2 Authorization Authorization to proceed with this study was granted by Mr. Mike Romano of Centurion Development Services on behalf of U.S. Land Development Associates. Our study was accomplished in general accordance with our scope of work letter dated September 24, 2001. This report has been prepared for the exclusive use of U.S. Land Development Associates and their agents, for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. 2.0 PROJECT AND SITE DESCRIPTION Our understanding of the proposed project is based on our discussions with Centurion Development Services, and on a plan sheet titled Plat of Evendell, dated May 20, 2001. The proposed project would include construction of a new plat. The new plat would include 75 new detached, single-family home sites, a recreation tract, two surface water detention tracts, and an existing area that has been identified as a wetland area that will remain. New paved November 16, 2001 ASSOCIATED EARTH SCIENCES, INC. MAMlda -KE0/617.AI -Projtm\20016/7\KE\IVP-i.v:?K Page I Evendell Preliminary Pia/ King Counry, Washington Subswface Explora/ion and Preliminary Geotechnica/ Engineering Repon Project and Site Conditions access roads, buried utilities, and other typical improvements are also planned. At the time this report was prepared, no grading plans were available; however, we assume that most of the project will be built near existing grades, without large excavation cuts or structural fills: . · Preliminary plat plans call for an open detention pond in the south detention tract, and a buried detention vault in the west detention tract. The project site is irregularly shaped, and approximately 12.4 acres in total area. The site is bordered to the north by SE 136"' Street, to the west by 160th Avenue SE, and to the south and west by existing residential development. Overall vertical relief across the site is on· the order of 35 feet, and areas in excess of 15 percent slope are not present, based on topographic information on the previously referenced plan sheet. No surface water was observed on site during our subsurface exploration. At the time of our field study, site vegetation consisted of mature evergreen and deciduous trees, with moderately dense undergrowth, pasture on the west and south parts of the site, and landscaping around the existing house on the north central part of the site. A wetland, mapped by others, was located in the northeast corner of the site. Existing site development included a home with outbuildings on the north central part of the site, a fenced pasture and several outbuildings on the west part of the site, and a fenced pasture on the south edge of the site. The existing house on the north central part of the site has an existing septic drainfield southwest of the house. 3.0 SUBSURFACE EXPLORATION Our field study included excavating 12 exploration pits to gain information about the site. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in the Appendix. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. Our explorations were approximately located in the field by measuring from known site features shown on the previously referenced site plan. The conclusions and recommendations presented in this report are based on the 12 exploration pits completed for this study. The number, location, and depth of the explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. Existing fill should be expected around the existing buildings and drainfield. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. November 16, 2001 ASSOCIATED EARTH SCIENCES, INC. MAM(da -K£0/6! 7AJ -Projtc1J\2CXJ/6171K£11VP -w:?K Page 2 Evende/1 Preliminnry Plat King County, Washington 3 .1 Exploration Pits Subsurface Exploration and Preliminary Geotechnical Engineering Repon Project and Site Conditions Exploration pits were excavated with a track-mounted backhoe. The pits pennitted direct, visual observation of subsurface conditions. Materials encountered in the exploration pits were studied and classified in the field by a geologist from our firm. All exploration pits were backfilled immediately after examination and logging. Selected samples were then transported to our laboratory for further visual classification and testing, as necessary. 4.0 SUBSURFACE CONDITIONS Subsurface conditions on the parcel were inferred from the field explorations accomplished for this study and a visual reconnaissance of the site. As shown on the field logs, the exploration holes generally encountered medium dense grading to very dense, silty sand with gravel interpreted as lodgment till. Topsoil thickness observed in our exploration pits varied from a minimum of approximately 0.5 foot to 1.2 feet. 4.1 Stratigraphy Natural soils observed in our exploration pits consisted of silty sand with gravel, trace cobbles, arid trace boulders interpreted as lodgment till. The till was observed to be loose to medium dense at the ground surface, and progressively more dense with increasing depth below the ground surface. The till was typically dense to very dense below approximately 5 feet in depth. The color of the till soils typically graded from brown near the ground surface, to mottled gray at a depth of 2 feet to 5 feet, to gray below approximately 5 feet. Lodgment till was deposited at the base of an active continental glacier, and was compacted by the weight of the overlying glacial ice. Till typically has high strength and low compressibility characteristics, and .is considered suitable for structural support with proper preparation. Till sediments typically contain a significant amount of silt, and are considered moisture sensitive. Moisture sensitive soils are prone to disturbance when wet, and typically perform best in construction applications when dry site and weather conditions prevail. Our interpretations of subsurface conditions are consistent with published information sources, as represented by the Washington State Department of Water Resources Water Supply Bulletin 28, Plate I, Geologic Map of Southwestern King County, Washington. This map indicates that the site is underlain by lodgement till. Although not encountered in our exploration pits, disturbed/fill soil is present, adjacent to the existing structures on the site and around any underground utilities. This non-structural fill is not considered to be suitable for foundation support. November 16, 2001 ASSOCIATED EARTH SCIENCES, INC. MA,\,f/tfa-K£0J6/7rl/ -Projtcts1'20016/7\KE!WP-w:?K Page 3 Evendell Preliminary Plat King County, Washington 4.2 Hydrology Subsurface Exploration and Preliminary Geotechnical Engineering Repon Project and Site Conditions Ground water seepage was encountered in exploration pit EP 0 8 near the interface between weathered till and till sediments. Wet soil conditions were also observed in exploration pit EP- 12 near the interface between weathered till and till sediments at a depth of 8 feet, though no free ground water was observed. The observed ground water conditions are interpreted to represent a perched ground water condition where vertical infiltration of surface water is impeded by lower permeability soils at depths. Ground water conditions should be expected to vary with changes in season, weather, on-and off-site land usage, and other factors. November I 6, 2001 ASSOCJATED EARTH SCIENCES, INC. MAM!da -KE0/6!7Al -Projrm\'2001617\KE\WP-W:!K Page 4 Evendell Preliminary Plat King County, Washington Subsurface Exploration and Preliminary Geotechnical Engineering Repon Design Recommendntions II. DESIGN RECOMMENDATIONS 5.0 INTRODUCTION Our exploration indicates that from a geotecill;iical standpoint, the parcel is suitable for the proposed development provided the recommendations contained herein are properly followed. The bearing stratum of dense lodgement till is located at approximately 1 foot to 2 feet below existing grades. Conventional spread footing foundations that bear on the medium dense lodgement till may be used for building support. 6.0 EROSION HAZARDS AND MITIGATION To mitigate and reduce the erosion hazard potential and off-site soil transport, we recommend the following: 1) All storm water from impermeable surfaces should be tightlined into approved storm water drainage systems or temporary storage. 2) Silt fences should be placed along the lower elevations of cleared and disturbed areas on the site. 3) Construction should proceed during the drier periods of the year or temporary erosion and sediment control plans should be developed if construction is to proceed during the winter months. Disturbed areas should be revegetated as soon as possible. 4) Soils that are to be reused around the site should be stored in such a manner as to reduce erosion. Protective measures may include, but are not necessarily limited to, covering with plastic sheeting or the use of hay bales/silt fences. 7.0 SITE PREPARATION Old foundations presently on the site that are under building areas or not part of future plans should be removed. Any buried utilities should be removed or relocated if they are under building areas. The resulting depressions should be backfilled with structural fill as discussed under the Structural Fill section. Site preparation of planned building and road areas should include removal of all trees, brush, debris, and any other deleterious material. Additionally, the upper organic topsoil and any fill . November 16, 2001 ASSOCIATED EARTH SCIENCES, INC. MAM Ida -KEOJ6/7AI -Projms\~0016/ 71K£1WP -\V2K Page 5 Evende/1 Preliminary Plat King County, Washington Subswface Exploration and Preliminary Geotechnica/ Engineering Repon Design Recommendations soils, if encountered, should be removed and any remaining roots grubbed. Areas where loose surficial soils exist due to grubbing operations, should be considered as fill to the depth of disturbance and treated as subsequently recommended for structural fill placement. Since the density and moisture content of the soil at the site are variable, random loose or wet pockets may exist, and the depth and extent of stripping can, therefore, be best determined in the field by the geotechnical engineer. Stripping depths are expected to be on the order of I foot, but are expected to vary locally. We recommend that building and roadway areas be proof-rolled with a loaded, tandem-axle dump truck to identify any soft spots. Soft areas should be overexcavated and backfilled with structural fill. In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, we anticipate that temporary, unsupported cut slopes in the till sedirn~nts can be planned at a maximum slope of lH:IV (Horizontal:Vertical). As is typical with earthwork operations, some sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times. 8.0 STRUCTURAL FILL All references to structural fill in this report refer to subgrade preparation, fill type, and placement and compaction of materials as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. Construction plans are preliminary at this stage and do not include site grading information or building footprint locations. However, placement of structural fill may be necessary in order to achieve the desired site grades in some areas. After overexcavation/stripping has been performed to the satisfaction of the geotechnical engineer, the upper 12 inches of exposed ground in building areas or areas to receive fill should be recompacted to 90 percent of the modified Proctor maximum density using ASTM:D 1557 as the standard. If the subgrade contains too much moisture, adequate recompaction may be difficult or impossible to obtain and should probably not be attempted before allowing the sub grade to dry/drain adequately. After recompaction of the exposed ground is tested and approved, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts with each lift being compacted to at least 95 percent of ASTM:D 1557 as the standard. Organic topsoil is not considered suitable for use as structural fill. Lodgement till soils may be used as structural fill if properly November 16. 2001 ASSOCIATED EARTH SCIENCES, INC. MAM/dtJ -KE0/617A/ -Projemr::OOJ617\K£l\VP-W2K Page 6 ) Evende/1 Preliminary Plat King County, Washington Subsu,face Exploration and Preliminary Geotechnica/ Engineering Repon Design Recommendations handled and moisture conditioned. In the case of roadway and utility trench filling, the backfill should be placed and compacted in accordance with applicable municipal codes and standards. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the location of the perimeter footings or roadway edge before sloping down at an angle of 2H: 1 V. The contractor should note that any proposed fill soils should be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the material 72 hours in advance of filling activities to perform a Proctor test and determine its field compaction standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Virtually all of the on-site soils are classified as moisture-sensitive, and were judged to be at or above optimum moisture for compaction. Thus, they should be considered suitable for reuse as structural fill only for dry weather and dry subgrade conditions. In addition, construction equipment traversing the till soils when wet can cause considerable disturbance. If fill is placed during wet weather above the till subgrades or if proper compaction cannot be obtained in these areas, a select import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction. A representative from our finn should inspect the stripped subgrade and be present during placement of structural fill to observe the work and perform a representative number of in- place density tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses and any problem areas may be corrected at that time. It is important to understand that taking random compaction tests on a part-time basis will not assure uniformity or acceptable performance of a fill. As such, we are available to aid the owner in developing a suitable monitoring and testing frequency. 9.0 FOUNDATIONS Spread footings may be used for building support when founded directly on structural fill placed as previously discussed or on medium dense to very dense, lodgement till soils. We recommend that an allowable bearing pressure of 2,000 pounds per square foot (psf) be used for design purposes, including both dead and live loads, for footings placed on till or approved structural· fill placed as discussed above. An increase of one-third may be used for short-term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost protection. All footings must penetrate to the prescribed bearing stratum, and no footing should be founded in or above organic, non-structural fill, or soft/loose soils. Footings should have a minimum width of 14 inches for I-story structures, with 2 inches of width added for each additional story. November 16. 2001 MAMlda -KE0/617,H -ProjwJIW0/617\KE\WP-W2K ASSOCIATED EARTH SCIENCES, INC Page 7 Evende/1 Preliminary Plat King County, Washington Subsurface Exploration and Preliminary Geotechnical Engineering Repon Design Recommendations The area bound by lines extending downward at lH: 1 V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of ASTM:D 1557. In addition, a l.5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the bearing soils. Anticipated settlement of footings founded as described above should be on the order of 1 inch or less. However, disturbed soil not removed from footing excavations prior to footing placement could result in increased settlements. All footing areas should be inspected by AES! prior to placing concrete to verify that the design bearing capacity of the soils has been attained and that construction conforms to the recommendations contained in this report. Such inspections may be required by the governing municipality. Perimeter footing drains should be provided as discussed under the section on Drainage Considerations. 10.0 FLOOR SUPPORT A slab-on-grade floor may be constructed directly ·on structural fill or medium dense, natural ground. Areas of slab subgrade that are disturbed (loosened) during construction should be compacted to a non-yielding condition. Where moisture migration through the floor slab is to be controlled, such as in occupied portions of the house, the floor should be cast atop a capillary break. The capillary break layer should consist of 4 inches of washed pea gravel covered with a polyethylene plastic vapor barrier. Based on American Concrete Institute recommendations, we also suggest placing a 2-to 3-inch layer of clean sand over the vapor barrier to protect the vapor barrier and to allow some moisture loss through the bottom of the slab to aid in the curing process. Sand should be used to aid in the fine-grading process of the subgrade to provide uniform support under the slabs. 11.0 DRAINAGE CON SID ERA TIO NS Traffic across the site soils when they are moist or wet will result in disturbance of the otherwise firm stratum. Therefore, prior to site work and construction, the contractor should be prepared to provide drainage and subgrade protection, as necessary. All perimeter footing walls should be provided with a drain at the footing elevation. Drains should consist of rigid, perforated, PVC pipe surrounded by washed pea gravel. The level of the perforations in the pipe should be set approximately 2 inches below· the bottom of the footing. The drains should be constructed with sufficient gradient to allow gravity discharge away from the building. Roof and surface runoff should not discharge into the footing drain system but should be handled by a separate, rigid tightline drain. In planning, exterior grades November 16, 2001 ASSOCIATED EARTH SCIENCES, INC. MAM!da -KE0/617,H -Projtc1sl~(X)/6/ 7'1KE\WP -W'.!K Page 8 ) Evende/1 Preliminary Plat King County, Washington Subsurface Exploration and Preliminary Geotechnical Engineering Repon Design Recommendntions adjacent to walls should be sloped downward away from the structure to achieve surface drainage. 12.0 PROJECT DESIGN AND CONSTRUCTION MONITORING At the time of this report, site grading, structural plans, and construction methods have not been finalized. We are available to provide additional geotechnical consultation as the project design develops and possibly changes from that upon which this report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the foundation depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of this current scope of work. · If these services are desired, please let us know and we will prepare a proposal. We have enjoyed working with you on this study and are confident that these recommendations will aid in the successful completion of your project. If you should have any questions, or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Melissa A. r.fagnuson, P.E. Senior Staff Engineer Attachments: Figure I: Figure 2: Appendix: November 16, 2001 Vicinity Map Site and Exploration Plan Exploration Logs MAM Ida -KEOJ6/7A I -ProftCIS\'2001617\KE\\VP -W2K Bruce L. Blyton, P. E. Principal Engineer ASSOCIATED EARTH SCIENCES, INC. Page 9 s f ' ' • i Associated ]~ la Earth Science5, Inc, ~ ~ ~ !.OOOFl'.l'.l -· PNl!cd l'rQm TO?OI Cl998 Wildfk:11nr Proda:ticns (www.lopo.tom) VICINITY MAP EVENDELL PRELIMINARY PLAT KING COUNTY, WASHINGTON FIGURE 1 DATE 11/01 • a ________________________________ __;,,:__;,,:_;,::_~;__ PROJ. NO. KE01617A .~ lbtonnce; c.-0.,.."*>!m*,._ S.-..C. .p ""' .,, ""' 20· R-4 90' I 90' ~ It; 2 . ~"' "" 25' ~ 0 1~. : J ffl~", 0 4 ~, (~ 90' rc-Jf fjJ EP-12\j~ CV tfJDffD1 WI I Jg"'II l Im\. I 7~'D ('dlOC tlM..) ~-= -.JUI mlllF>« -... ,..a a:JJDCf•4nJI IIU7tl(:l[J',OL•J0.2DDrJ ..-c,aa.--ts(&.ITCO'IM) @ R-4 @I _90' __ 6 -~ 103' ~() ~ ().//1~ "° ill llO. R-4 ~ x:,,,,, ' ~,,:::::::c:::,s:.;;;;;s ~ •' <>' :--~ : Wr. = 90· , , m~,, \\8 0 O u ! Q ~ 90• 99• • ,,· •I ~".-----'r----'i,,---t.;~ 8':, 11\ 47 103· 1ro· ~ 48 I I 1l ,,· I°!;! 46 52 '·. ,- ii1 ~ ~ ' . 1 61 fg ~· 1 43 ,,. ~I ~ ~ ,o· I ,.. ~: ·. i!] j-a ,oo· \ ~. 1,J: 1 : 1 : Ji. JS i JS ,·~------ i::: @ 34 '" . ......, "' .~ 12 i _,,._ 13 c @~ • .,. @ 14 ~ ,,. 'o 16 I 0 ~f ~ 18 ~ -----..,- ' ,, .,,... ati• l <>a.----.-·Ao' "'1: ""' -7 a9· . • ag' o •9' 40•- • 58 ~ 75·~4"' 73 1 · ;2 57 ,5· 45• ~ 72 95• 30 t ' 29 : " "' .,,. 58 ~I 58~ ~ 70;,;,,_ ~ 71 ~ as· ~~-~ya,-ll' cd"CDT. US£ ORl','EW.\T '-<l!J' :"-'1"" TRACT 1-1' / Ill 31 'o eo·o ea b:;; 118 ' ~ ' , .. ~ m a,· . i:'i 82 0 47' ,1.7" r'I tr1 ' -· < ,., I ) ~--,O' 0 i"' 31 '.i .1~· I 20· ~ ~ PRIVATE ACCESS ro IN m,.cr '(" I"' ,,-20 ,0: Iii EP-4 ~ 27 ~I 28 . ~ g 1...1.Q_' 205' R(CREATlOM .RA.CT 'K" I ~.868 Sf 2os· ~ ~~~=~\\ '" 17 ~ \ 64 J ea 1 ea / ' \\\ ' \) ; • ;9' ~83 "g l 'I;!, EP-/ \~ \\~! I 1·. D CT. / ',(C I 11, _ • 1 • . _,, , \\' 1 :wEP,.3 1 I § F ',! " ' ' " . , ' I I ~ ' // J; ·1 ,,." ·1 1 ':'· 'I ' I " " I ' ' J " d ' ~ o J , I ~"'I 24 ;; 2!5 •! \, . . ~ ' ;,I 22 ° ..., " I -.... ' -, r!l 9 ·-20 Ji 2 1 0 ! ·1 i , . . I ·o· ! J -~ N I 1 I I ' I . I "'O" I ~ ~OC{-.. ,.D , I I,. ,o ;;:"'=·= A , ' ' .. < • -··:,·-·. ·-<:f 1 • 0 • I ,o· ' · ~•;::-. ·•=g· ' < ~.'i!c.,,;;,,,,_ • ~ 120 f'EET ~"" ()v Isa) '-' Associated Earth Sciences, Inc. SITE AND EXPLORATION PLAN EVENDELL PRELIMINARY PLAT KING COUNTY, WASHINGTON ~~~~[(J '"°" cP '"°"' ()() -· "" <>' ,,p ""' ~".) cP "" "'"' ~ 0() R-4 LEGEND EP-1 [I Approximal e location of exploration pit FIGURE 2 DATE 11/01 PROJECT NO. KE01617A ~ ~ .. in g "' 0 z C 0. .., .. C :I! .. 0: ~ ill C .. 5 !! ~ . • "C C .. CD • G • 0 C) Well-graded gravel and GW gravel with sand, little lo no fines GP Poorly-graded gravel and gravel with sand, little ta no lines Silty gravel and silty GM gravel with sand Clayey gravel and GC clayey gravel with sand Well-graded sand and SW sand with gravel, little to no fines Poorly-graded sand SP and sand with gravel, little ta no fines SM SC Silty sand and silty sand with gravel Clayey sand and clayey sand with gravel Terms DP.scribing Relative Density and Consistency Density SPTC2\ilowsJfaot Coarse-Ve,y Loose Oto4 Grained Sails Loose 41D 10 Medium Dense 10 to 30 Test Symbols Dense 301050 Ve,yDense >50 G = Grain Size M = Moistl.Jre Coo1ent Consistency S~lows/foot A = Attert:lerg Limits C = Chemical Fone-Ve,y Soft Oto2 DD=DryD~ Son 2to 4 K = Permeability Grained Soils Me<flUrTI Sliff 4to 8 Sliff Sto 15 Ve,y Stiff 15 lo 30 Hard >30 Component Definitions Desaiptive Term Size Range and Sieve Number Boulders Cobbles Grava Coarse Gravel Fine Gravel Sand Coarse Sand Mecfrum Sand RneSand Larger than 12' :r ta 12' :r lo No. 4 (4.75 mm) 3• to 314" 314" to No. 4 (4. 75 mm) No. 4 (4.75 rm1) to No. 200 (0.075 mm) No. 4 (4.75 mm) to No. 10 (2.00 mm) No. 10 (2.00 mm) to No. 40 (0.425 mm) No. 40 (0.425 mm) to No. 200 (0.075 mm) Silt and Clay Smaller than No. 200 (0.075 mm) (J) Estimated Percentage Moisture Content Component Percentage by Dry -Absence of moisture, --l--'--lifrfl'n'il--1---------i Traca Few Little With Weight dusty, dry to the touch Sightly Moist -Perceptible rnoisnire ~ .. ;;; ~ ci z • .. • • .. c.. 1! 0 :::; Sil~ sandy silt, gravelly silt, ML silt with sand or gravel CL Clay of low to medium plasticity; silty, sandy, or gravelly clay, lean clay Organic clay or silt of low OL plasticity -Sampler Type Bastic silt, clayey silt silt 2.0" 00 with micaceous or Spla-Spoon diatomaceaus fine sand or Sampler IB'M--P's"'ill--,-,--,-----1 (SPT) Clay of high plasticity, sandy or gravelly clay, fat Bulk sample c!ay with sand or gravel MH CH <5 5 to 10 15 to 25 • Noo-prinary coarse constitlJents: ~ 15% • Fines content between 5% and15% Moist • Damp but no visible water Ve,y Moist -Water visible but not free draining Wet-Visible free water, usually from be/cw water table Symbols 81°""'6"' or porfun of s· I • • • Sampler Type Description 3.0" OD Spla-Spoon Sampler ,., Cemf!ftgrcut sunacaseal eentome .... 3.25" OD Split-Spoon Ring Sampler ·: nlleq:,adc wih ·: blank c:aslng •. sect!on • 3.ll" OD Thin-Wall Tube Sampler [mduding Shelby tube) Sa9tlfllld c:aslng orHyaotlp --pad< End cop i-•J Depth cf grcuncwater :i: ATD = Al time of dnlling Sl · Static water level (datll) (5) Combined uses symbols used for lines between 5% and 15% ~ns ot soib in :hi3 report ara based oo visu.aJ l'ield and/or labcr.lto,y observ:ation:s. whid1 induch~ den:sity/a,mistency, moistun, a::n:iition, grain size, nd pb5txity 83timate~ and should not be con:stn.Jed to imply fleMj or laboratory lasdnQ unloss pnJSentad hereil"I. ~uai andfor laboratory Ca55incadon methods cl ASTh1 G~2487 and 0-2488 wtmi u5ed a, an idnmtr\Catlon guide for !he Uoifted Soa Cla:s.:srtlcatlon S~ ?================================================= ll FlQJRE 0 j! . EARTI< "'-};c~S] ASSOCIATED ] , · ' SCIENCES, INC Exploration Log Key A-1 ~-----------------------------------------'--------- g ,5 a. Q) 0 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - __ LOG OF EXPLORATION PIT NO. EP-1 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read tqgether with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Grass Weathered Till Loose to medium dense, damp, reddish brown, SIL TY fine SAND, little fine gravel. (SM) Till Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND, some fine to coarse gravel, trace cobbles. (SM) Becomes very dense and less mottled. (SM) Bottom of exploration pit at depth 8 feet NO ground water seepage or caving. Elevation 467'. ~----------------------------------------------':! Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ASSOCIATED EARTH . SCIENCES, INC Project No: KE01617A November 2001 £ C. " 0 1 - _ LOG OF EXPLORATION PIT NO. EP-2 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read tqgelher with Ulat report for complete interpretaUon. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of lime. The data presented are a simptficalion of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff Weathered Till Loose to medium dense, moist, reddish brown, SIL TY fine to medium SAND, little fine gravel. (SM) 2 -l------~---------~T=il~I ---------------- Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND, some fine to coarse 3 -gravel, trace cobbles. (SM) 4 - 5 - 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Becomes very dense and Jess mottled. (SM) Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 465'. ~--------------------------------------'-------.; ~ 0 ~ ~ Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA .JI!!!:! fl.lf1I! ASSOCIATEO #&WJIIUfl ~~:g.~ES, INC li ____________ '------------------ Project No, KE01617A November 2001 g g_ " 0 _ LOG OF EXPLORATION PIT NO. EP-3 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read tqgetherwith that report for complete Interpretation. This summary applies only to the locaUon of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff 1 -Weathered Till 2 - 3 - 4 - 5 - 6 - 7 - 8 - g - 10 - 11 - 12 - 13 - 14 15 - 16 - 17 - 18 - 19 - Loose to medium dense, damp, reddish brown, SIL TY fine SAND, trace fine gravel. (SM) Till Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND, some fine to coarse gravel, few cobbles. (SM) Grades to moist to wet (no free water) to bottom of exploration pit. Grades to very dense and less mottled. (SM) Bottom of exploration pit at depth 14 feet No ground water seepage or caving. Elevation 458'. i-------------------------------------------,.; . J • 0 n ~ ~ Logged by: BWG Approved by: ---------------------------- Project No. KE01617 A November 2001 g 5 a. m 0 LOG OF EXPLORATION PIT NO. EP-4 This Jog is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete Interpretation. This summary applies only lo the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff 1 -1-----------------=-cc--,,=~-----------------Weathered Till 2 -Loose to medium dense, moist, reddish brown, SIL TY fine SAND, little fine gravel. (SM) 3 - Till 4 -Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND, little to some fine gravel. (SM) 5 - 6 -Very dense, damp, gray, SIL TY fine SAND, little fine gravel. (SM) 7 - 8 - 9 - 10 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit al depth 10 feet No ground waler seepage or caving. Elevation 464'. !!---------------------------------------------..; Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ~ SIASSOCIATEO .,~~ ~~~~ES, INC Project No: KE01617A November 2001 1 2 - 3 LOG OF EXPLORATION PIT NO. EP-5 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff Weathered Till Loose to medium dense, damp, reddish brown. SIL TY fine SAND, little fine gravel. (SM) Till Medium dense to dense, damp, mottled gray, SILTY fine to coarse SAND, some fine gravel. (SM) 4 - 5 - 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Becomes very dense and gray. (SM) Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 468'. g-~[J--------------------------------------N--------------------------------------------- ~ " ,_; ;;; ;; M ~ r Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ~ V,IASSOCIATEO 1&~11~~~'1:es, INC Project No, KE01617A November 2001 "---------------------------------------------- g £ 0. " 0 1 - 2 - 3 LOG OF EXPLORATION PIT NO. EP-6 This log is part of the report prepared by Associated Earth Sciences, Inc. {AESI) for the named project and should be read togettier with that report for complete interpretation. This summary applies only to the localion of this trench at the time of excavation. Subsurface condiUons may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff Weathered Till Loose to medium dense, damp, reddish brown, SIL TY fine SAND, little fine gravel. (SM) Till Medium dense to dense, damp, mottled gray, SIL TY fine SAND, little fine gravel, trace cobbles, 4 -trace boulders. (SM) 5 - 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Becomes very dense and gray. (SM) Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 474'. ~---------------------------------------------..; 1 j " :: w 0 M ~ ~ Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA JI!!! ~ASSOCIATED L~w81~~~'1:Es, INC Project No, KE01617A November 2001 --------------------------------- §: £ C. ., 0 LOG OF EXPLORATION PIT NO. EP-7 This log is part of Ule report prepared by Associated Earth Sciences, Inc. (AES!) for Ule named project and should be read together with that report for complete Interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface condiUons may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff 1 -1-------------~~-~~~-------------Weathered Till 2 -Loose to medium dense, damp, reddish brown, SIL TY fine SAND, some fine gravel. (SM) Till 3 -Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND, little to some fine to 4 -coarse gravel, trace cobbles. (SM) 5 - Becomes very dense and gray. (SM) 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 4 73'. ~----------------------------------------,:! i z ~ ~ ;! ~ 0 ~ Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ASSCICIATEO EARTIHI SCIENCES, INC Project No. KE01617A November 2001 la' _____________________________________________ _ = 0. w 0 __ LOG OF EXPLORATION PIT NO. EP-8 This log is part of the report,frepared by Associated Earth Sciences, Inc. (AESI} for the named project and should be . read togeUier with that repo for complete interpretation. This summary applies only to the locaUon of this trench·at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff 1 -.----------------------------~-----------Weathered Till 2 _ Loose to medium dense, moist, reddish brown, SIL TY fine to medium SAND, little fine gravel. (SM) 3 -+------------------T=u-1 ________________ _ Medium dense to dense, wet, mottled gray, SIL TY fine to coarse SAND, little to some fine gravel, 4 -trace cobbles. (SM) 5 - 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Becomes very dense and gray. (SM) Bottom of exploratlon pit at depth 9 feet Weak ground water seepage from 3'-6 developed after 1/2 hour. No caving. Elevation 476'. ~----------------------------------------------<j i 0 z 2 !'! ~ ;; M ~ Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA JS SI-ASSOCDATEO rAmA · EARTH ~ SCIENCES, INC Project No. KE01617A November 2001 ~---------------------------------------------- g £ a. m 0 LOG OF EXPLORATION PIT NO. EP-9 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read tqgether with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditlons may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Forest Duff 1 -Weathered Till Loose to medium dense, damp, reddish brown, SIL TY fine to medium SAND, trace fine gravel. 2 -(SM) Till 3 -Medium dense to dense, damp, mottled gray, SIL TY fine to coarse SAND with fine to coarse gravel, 4 - trace cobbles. (SM) 5 -Grades to very dense and gray. (SM) 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 482'. ij ____________________________________________ _ g Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ~ 4(t,if ASS0CBATEO l~ffl~~~~ES, INC Project No._ KE01617A November 2001 !;!----------------~---------------------------- 0 g 5 C. " 0 1 - __ LOG OF EXPLORATION PIT NO. EP-10 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI} for the named project and should be read togeUier with that report for complete interpretation. This summary applies only to the locaUon of this trench at the lime of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Grass Weathered Till Loose to medium dense, damp, reddish brown, SIL TY fine to medium SAND, little fine to coarse 2 _ gravel. (SM) 3 - 4 - 5 - 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Till Medium dense to dense, moist, mottled gray, SIL TY fine to coarse SAND, some fine to coarse gravel. (SM) Becomes very dense and gray. (SM) Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 492'. ~----------------------------------------------:! ! 1 ~ ~ M ~ Logged by: BWG Approved by: Project No0 KE01617A November 2001 ~---------------------------------------------- §: 5 0. " 0 __ LOG OF EXPLORATION PIT NO. EP-11 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report. for complete interpretation. This summary applies only to the location of this trench at the Ume of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil and Grass Weathered Till 1 -Loose to medium dense, damp, reddish brown, SIL TY fine SAND, little fine to coarse gravel. (SM) 2 - 3 4 - 5 - TIii Medium dense to dense, moist, mottled gray, SIL TY fine to coarse SAND with fine to coarse gravel, trace cobbles. (SM) Grades to very dense and gray. (SM) 6 - 7 - 8 - 9 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit at depth 9 feet No ground water seepage or caving. Elevation 488'. i-------------------------------------------,.; ~ 0 ~ • ~ Logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ~ ~ASSCCDATEC i.&~11~~~81:es. DNC Project No. KE01617A November 2001 ~------------------------------------------- g 5 C. Q) 0 _ LOG OF EXPLORATION PIT NO. EP-12 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this locaUon with the passage of lime. The data presented are a simplfication of actual conditions encountered. DESCRIPTION . Topsoil 1 -Weathered Till Loose to medium dense, damp, reddish brown, SIL TY fine lo medium SAND, few fine gravel. (SM) 2 - 3 - Till 4 -Medium dense to dense, moist to wet, mottled gray, SIL TY fine to coarse SAND, some fine to 5 - coarse gravel, trace cobbles. (SM) Becomes very dense, wet, and gray. (SM) 6 - 7 - 8 - 9 - 10 - 11 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit at depth 11 feet No ground water seepage or caving. Elevation 484'. ----z'fl---------------------------------------li---------------------------------------------..; j ~ ~ ~ ;;; 0 2 5 logged by: BWG Approved by: Evendell Preliminary Plat King County, WA ,/l!!!!_ 'lflljASSCCIA"ll"EC .l'A:Jl~~:l~es, INC Project No. KE01617A November 2001 ~--------------------------------------------- 05/10/2004 15:08 2535390514 HABITAT 1f'ECHN00.0Gl1ES October 28, 2002 Centurion Development Services 22617 -8111 Drive SE Bothell, Washington 98021 SOUNDBUILT HOMES RE: ADDENDUM to the Wetland Evaluation and Delineation Report, Wildlife Habitat Evaluation, and Conceptual Wetland Mitigation Plan for the Evendell Project Site Dear Mr. Romano, PAGE 02 Subsequent to the preparation of the "Wetland Evaluation and Delineation Report, Wildlife Habitat Evaluation, and Conceptual Wetland Mtfigation Plarf for the Evendell Project Site, (Habitat Technologies, May 2001) the Selected Action Plan has been modified. This addendum describes the changes from the original report. The Evendell Project Site is approximately 14 acres in total size and is located east of the City of Renton, King County, Washington. Onsite assessment of the project site following the procedures outlined in the Washfngton State Welfands Identification and Delineation Manual (Wash. Manual) end the Corps of Engineers Wetlands Delineation Manual (1987 Manual) resulted in the identification of one area (Wetland A) that exhibited hydric soils, wetland hydrology, and hydrophytic vegetation consistent with the established criteria of both the Wash. and 1987 Manuals. · The preliminary Selected Action Plan of the Evendell project site included the creation of independent lots suitable for the development of single-family homesites consistent with the King County Comprehensive Plan. Buffer averaging was to be used along the western boundary of the onsite wetland as a part of this lot creation. Selected Action Plan The Selected Action Plan of the Evendell project site focuses on the creation of independent lots suitable for the development of single-famfly homeaites consistent with the King County Comprehensive Plan (Attachment 1 - Preliminary Plat). An essential element of this process is the development of \ access roadways and utility corridors that meet both King County health and safety standards and the goal of avoidance and minimization of potential short- term or long-term adverse impacts to aquatic environments. wetlands, streams, flsheri°", wildllfe -mlt15ation and pamdttlng solutions P.O. Box 1088, Puyallup, Washingtan 98371 voice 253-845-5'119 fax 253-841-'1942 Evendell -1 00082 Wetfandl'NddTr!a Report ADDENDUM ,, 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 03 A primary feature in the creation of these homesite lots will be the establishment of a protective buffer adjacent to the identified onsite wetland consistent with King County Sensitive Area codes. The creation of these homesite lots will not require placement of fill within identified wetland areas or reduction of the standard buffer width as previously proposed. Site development requires construction of road improvements within existing unopened SE 136th Street right-of-way along the northern project boundary. This will require the unavoidable filling of the northem 200 square feet of Welland A • and reduction of the associat~ buffer by 4,649 square feet. In addition: in response to King County staff concems, the applicant has proposed constructing road frontage improvements along 160111 Avenue SE consisting of a paved shoulder and relocation of the drainage ditch.. This will require the unavoidable intrusion into 2,340 square feet of the buffer for Wetland A. As mitigation for the unavoidable loss of wetland and buffer associated with required road improvements, the wetland_buffer will be increased by the addition of 15,495 square feet of forested_area located in the northeast comer of the site between the eastern boundary of the wetland and 160th Ave. SE. Provision of this additional buffer fully compensates for the unavoidable · intrusions into the wetland and standard buffer areas and will not adversely impact the remaining wetland area. ELEMENTS OF THE BUFFER ADDITION AND WETLAND RESTORATION PLAN 1. The buffers associated with the identified onslte wetland will be established to the King County standard 50-foot width. Identified onsite wetland and associated buffers will nm be adversely impacted by future onsite land uses. 2. As a part of the development of the required roadway improvements the actual encroachment into buffer area of Wetland A will be held to the minimum necessary to meet County roadway requirements. Following placement of the roadway improvements the roadway side slopes within the buffer areas will be revegetated by seeding with an appropriate seed mixture. 3. As compensation for unavoidable encroachment into the north end of Wetland A, 400 square feet (a 2 to 1 ratio) of degraded wetland in the proximity of the edge of the roadbed will be enhanced through the planting af native trees and shrubs. This restoration will enhance wetland function by providing structural diversity in the plant community. 4. As compensation for unavoidable encroachment into the north end of the buffer associated with Wetland A and a portion of the buffer on the east side of WeUand A the standard buffer will be inc:eased to encompass the entire northeast comer of the property. This buffer width increase will enhance Evendell -2 OOD62 WellandN\/ildlife Report ADDENDUM ,, 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 04 wetland function relative to that provided by standard buffers through increased visual and auditory blockage from 1601h Ave. SE and greater conservation of wildlife habitat opportunities. !5. In order to protect the wetland and associated buffer erosion control Best Management Practices will be implemented during all phases of construction. These measures include sift fencing along the buffer prior to any onsite actions. In addition, an exposed areas will be seeded with low growing grasses upon the completion of onsite actions. 6. Alf activities related to the establishment of the buffer areas will be monitored by the project biologist. WETLAND RESTORATION AND BUFFER ENLARGEMENT PLAN The GOAL of the identified buffer addition plan is to ensure that proposed site development actions (i.e. the upgrading of an existing rigtrt-of-way roadway to meet King County health and safety standards) do not create a short-term or long-term adverse impact to the onsite wetlands or associated buffer areas. The total amount of King County jurisdictional wetland area to be unavoidably modified by this project equals 200 square feet. As compensation · for this unavoidable impact to Wetland A, 400 square feet (a 2:1 ratio) of remaining degraded wetland will be restored through the planting of native trees and shrubs. The total amount of King County jurisdictional buffer area to be unavoidably modified by this project equals 6,986 square feet. As compensation for this unavoidable impact to Wetland A, '15,495 square feBll (a 2.2:1 ratio) of area at the northeastern comer of the project will be dedicated to buffer area. The purpose of the Wetland Restoration Plan is two fold. Finst, to define the wetland restoration plan proposed as an element of the construction of the Evendell development. Second, to identify the objectives and criteria whereby the success of the completed wetland and buffer restoration plan will be determined. Evendell -3 00062 Wmland/Wlldlihl Report ADDENDUM 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 05 ·"'·-· HABITAT TECHNIOlOGIES WETLAND EVALUATION AND DELINEATION REPORT, WILDLIFE HABITAT EVALUATION, AND COMPENSATORY WETLAND MITIGATION PLAN EVENDELL RESIDENTIAL COMMUNITY King County, Washington Part of Section 14, Township 23 North, Range 5 East, W.M. prepared for Centurion Development Services 22617 -81h Drive SE Bothell, Washington 98021 prepared by HABITAT TECHNOLOGIES · P.O. Box 1088 Puyallup, Washington 98371-1088 253-845-5119 May 15, 2001 watl:.nds, stniams, fisheries, wildlife -mitigation and permitting solutions P.O. Box 1088, Puyallup, Washington 98371 voice 253-84S-5119 fax 253-841-1942 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 06 EXECUTIVE SlJMMARY The Evendell Residential Community is approximately 14 acres in total size and located to the east of the City of Renton, King County, Washington. The project site is comprised of two adjacent parcels; Parcel A of 11.5 acres, and Parcel B of 2.5 acres directly to the west of Parcel A. The Parcel A portion of the project site is dominated by a mature Douglas fir (Pseudotsuga menziesil) forest plant community on the periphery of the parcel that has been planted following prior forest harvest activities. A single- family dwelling is located in the northern portion of Parcel A. The center of Parcel A has been cleared and is dominated by a dense canopy of Himalayan blackberries (Rubus procera). The southern portion of Parcel A is dominated by active livestock pasture. Parcel 8 portion is dominated by an active livestock pasture which also contains a single-family dwelling and four associated buildings. 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 one 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 forest harvest activities and grading and was dominated by a mixture of deciduous trees and shrubs. This assessment, completed in accordance with King County regulations, included an evaluation of the function and value rating for the identified wetland, a classification of the wetland following the U.S. Fish and Wildlife methods, and an identification of the standard King County buffer width required for this·wetland. Onsite assessment also included an evaluation of the wildlife habitat availability and utilization. Species presence and habitat utilization were evaluated following the methods identified by Horner and Raedeke (1989) and within U.S. Fish and Wildlife Service Publication 80/58 (Mikol, 1980). In addition, the King County Wildlife Study Guidelines (Draft Wildlife Management in King County, Issue Paper, 1993) were followed to assure consistency with the King County permit process and documentation of habitat types. WETLAND SIZE ONSITE CLASSIFICATION KING COUNTY FUNCTION STANDARD (square feet) (USFWS) RATING ANO VALUE BUFFER RATING WIDTH A 17.162 PFOE, PEME 2 low 50 feet PFOE palustrme, forested, seasonally flooded/saturated PEME palustrlne, emergent, seasonally flooded The "habitat type" best represented within the site would be that of "young conifer upland forest -low understory. • This habitat type included three isolated freshwater wetlands and a mixed freshwater wetland drainage corridor. 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 07 PRIMARY HABITAT TYPES INCLUDED MINOR HABITAT TYPES Conifer Upland Forest Deciduous Forested wetland. . low understorv Aaricultural Lands Persistent Lowland Shrub The U.S. Army Corps of Engineers and King County, as well as a number of other local, state, and federal agencies, regulate activities in and around identified wetland and drainage corridor areas. Such regulations focus on the avoidance of adverse impacts to wetlands, streams, associated buffers and the mitigation of such impacts that cannot be avoided. King County has established criteria to categorize wetlands for purposes of regulation and the establishment of buffers. In addition, King County allows a limited amount of alterations to wetlands (i.e. isolated wetlands, roadway crossings) provided such impacts are mitigated pursuant to an approved mitigation plan. The Selected Action Plan of the Evendell project site focuses on the creation of independent lots suitable for the development of single-family homesites consistent with the King County Comprehensive Plan. Buffer averaging will be used along the western boundary of the onsite King County Class 2 Wetland (I.e. Wetland A) as a part of this lot creation. Such averaging will provide additional protection to wetlands and enhance the wetland's functions. In addition, improvements to the existing right-of-way (South 136th Street -a primary collector route for the area) which fronts the project along its northern boundary will require the unavoidable filling of the northern 200 square feet of Wetland A and the reduction of the buffer associated with this area of the wetland. Through restoration of the existing onsite wetland, addition of buffer area along the eastern side of Wetland A, and onsite erosion protections this unavoidable wetland intrusion will be fully compensated, will enhance onsite wildlife habitats, and will not adversely impact the remaining wetland area. The GOAL of the wetland mitigation and buffer averaging plan is to ensure that proposed site development actions (i.e. the improvement of an existing right-of-way to meet King County health and safety standards) do not create a short-term or long-term adverse impact to the onsite wetland or associated buffer areas. 05/10/2004. 15:08 2535390514 SOUNDBUILT HOMES PAGE 08 TABLE OF CONTENTS INTRODUCTION ............................................................................................................ 1 STUDY PURPOSE .................................................................................................... 1 SITE DESCRIPTION ................................................................................................... 1 BACKGROUND INF.ORMAilON ... , ................................................................................ 2 NATIONAL WETLAND INVENTORY MAPPING ......................................................... 2 STATE OF WASHINGTON PRIORITY HABITATS AND SPECIES ............................ 2 STATE OF WASHINGTON STREAM CATALOG ...................................................... 2 KING COUNTY SENSITIVE AREAS MAPPING ......................................................... 2 SOILS MAPPING ........................................................................................................ 2 AERIAL PHOTO ANALYSIS ...................................................................................... 3 ONSITE EVALUATION -WETLANDS ........................................................................... 3 WETLAND STUDY METHODS ................................................................................... 3 FIELD OBSERVATION .. , ............................................................................................ 4 ~ Vegetation ....................................................................................................... 4 cc Soils ................................................................................................................ 5 u Hydrology ........................................................................................................ 5 WETLAND AND STREAM DETERMINATION ............................................................... 6 WETLAND FUNCTION ANO VALUE ASSESSMENT .................................................... 6 ONSITE WETLAND VALUATION ............................................................................... 8 ONSITE EVALUATION -WILDLIFE .............................................................................. 9 WILDLIFE STUDY METHODS .................................................................................. 9 ONSITE HABITATTYPES ........................................................................ , .............. 10 PLANT AND ANIMAL SPECIES OBSERVATIONS ................................................ 10 MOVEMENT CORRIDORS ....................................................................................... 12 PRIORITY SPECIES ................................................................................................. 12 STATE CANDIDATE SPECIES ................................................................................ 12 REGULATORY CONSIDERATION .............................................................................. 12 U.S. ARMY CORPS OF ENGINEERS -SECTION 404 .............................................. 13 KING COUNTY -"ENVIRONMENTALLY SENSITIVE AREAS" ORDINANCE 21A.24 ............. 13 D Wetland and Stream Classes ........................................................................ 13 o Wetland/Stream Alteration ............................................................................. 14 D Roadway Improvements ................................................................................ 14 O Required Buffers ........................................................................................... 15 SELECTED ACTION PLAN ................................ ., ....................................................... 15 ELEMENTS OF THE COMPENSATORY MITIGATION PLAN ..................................... 16 DESCRIPTION OF THE COMPENSATORY MITIGATION PROGRAM .................... 17 GOAL AND OBJECTIVE OF THE MITIGATION PLAN ............................................. 18 PERFORMANCE CRITERIA ..................................................................................... 1 B MITIGATION REPLACEMENT/ENHANCEMENT ..................................................... 19 SUMMARY TABLE OF WETLAND FUNCTIONAL BENEFITS ................................. 20 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 09 SELECTED PLANT COMMUNITIES ........................................................................ 20 CONSTRUCTION INSPECTION ........... : ................................................................... 21 WATER QUALITY PROTECTIONS DURING CONSTRUCTION .............................. 22 CONSTRUCTION SEQUENCE ................................................................................ 22 PROJECT MONITORING ...................................................................................... 22 STANDARDS OF SUCCESS .................................................................................... 23 Vegetation Sampling Methodology and Monitoring Schedule ................................ 23 Vegetation Monitoring .............................................................................. : ............ 23 Vegetation Monitoring Sequencing ............................. : .......................................... 24 .WILDLIFE OBSERVATIONS .................................................................................... 25 VEGETATION MAINTENANCE PLAN ..................................................................... 25 CONTINGENCY PLAN ............................................................................................. 26 PLANTING NOTES ....................................................................... , ........................... 26 FINANCIAL GUARANTEE ........................................................................................ 26 FIGURESREFERENCE LIST ..................................... : ................................................. 27 REFERENCE LIST ....................................... ~ ............. ,.,u,, ........................ ,n,,, ................ 28 APPENDIX A,,,,~0&000,100,.,o,01,,,,,,,,,,,,,,,,,,,,.,,,,nooonu•u•••••••••••••n••••••••n1100,o,,no•u••••••••HOOIU 29 APPENDIX Bn.,, ................................................................................................................. 30 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 10 STANDARD OF CARE. Prior to extensive site planning, this document should be reviewed and the wetland boundaries verified by the appropriate resource and permitting agencies. Wetland boundaries, wetland classifications, wetland ratings, and all proposed wetland restoration and enhancement activities should be reviewed and approved by King County and potentially other regulatory staff. The above consultants have provided professional services that are in accordance with the degree of care and skill generally accepted in the nature of the work accomplished. No other warranties are expressed or implied.· The consultant is not responsible for design costs incurred before this document is approved by the appropriate resource and permitting agencies. Mark Heckert Senior Wetland Ecologist 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 11 INTRODUCTION This report details the culmination of activities and onsite evaluations undertaken to complete both a wetlands evaluation and a wildlife habitats assessment as an element of the planning and site development of the Evendell Project Site. The project area is approximately 14 acres in total size and generally located within a quickly urbanizing area east of the City of Renton, King County, Washington. The evaluation and delineation of onsite and adjacent wetlands; drainage corridors, and wildlife habitats is a vital element in the planning and selection of a site development action. The goal of this approach is to assure that planned site platting does not result in adverse environmental impacts to such areas. Wetlands are generally defined as "those areas of King County that are inundated or saturated by ground or surface water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions." (King County Environmentally Sensitive Areas). STUDY PURPOSE This purpose of this document is to present the results of the onsite assessment and evaluation of the wetland/drainage corridor areas and the wildlife habitats within the project area. Included within this report is an assessment of the proposed impacts and compensatory actions to be taken to ensure that proposed onsite actions do not adversely impact environmentally sensitive areas. This study was designed to accommodate site planning and potential regulatory actions. This report is suitable for submittal to federal, state, and local authorities for wetland boundary verification and permitting actions. SITE DESCRIPTION The project site is generally square in shape, approximately 14 acres in total size, and located within a rapidly urbanizing area generally east of the City of Renton, King County, Washington (Figure 1). The project site is comprised of two adjacent parcels; Parcel A of 11.5 acres, and Parcel B of 2.5 acres directly to the west of Parcel A. The Parcel A portion of the project site is dominated by a mature Douglas fir (Pseudotsuga menziesil) forest plant community on the periphery that has been planted following prior forest harvest activities. A single-family dwelling is located in the northern portion of Parcel A. The center of Parcel A has· been cleared and is dominated by a dense canopy of Himalayan blackberries (Rubus procera). The southern portion of Parcel A is dominated by active livestock pasture. Parcel B portion is dominated by an active livestock pasture which also contains a single-family dwelling and four associated buildings. Evendell -1 WetlandNVildlife Report. 00062 • 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 12 The project site is generally flat and rolling and a narrow drainage corridor area is present generally through the northeast corner of tlie Parcel A portion of the site. This narrow drainage corridor had been impacted by prior forest harvest actions (i.e. clearing, harvest, roadways, slash piles), and subsequent clearing and grading as part of homesite development activity. Surface drainage within this corridor is conveyed as overland flow to the southeast to the ditch that runs south along the western side of 1601h Avenue South. However, there is no evidence onsite of a continuous stream channel. BACKGROUND INFORMATION NATIONAL WETLAND INVENTORY MAPPING The National Wetland Inventory (NWI) mapping completed by the U.S. Fish and Wildlife Service was reviewed as a part of this assessment. This mapping resource did not identify any wetlands or drainage corridors on the project site. (Figure 2). STATE OF WASHINGTON PRIORITY HABITATS AND SPECIES The State of Washington Priority Habitats and Species (PHS) Mapping was reviewed as a part of this assessment. This mapping resource did not identify any Priority Habitats or Species onsite or within the immediate vicinity. STATE OF WASHINGTON STREAM CATALOG The State of Washington Stream Catalog for Puget Sound was reviewed as a part of this assessment. This mapping resource did not identify any streams within the project site. This mapping did identify the Green River to the south of the project site. The Green River was identified to provide habitat for a number of anadromous and resident salmonid fish species. KING COUNTY SENSITIVE AREAS MAPPING The King County Sensitive Areas Mapping was reviewed as a part of this assessment. This mapping resource did not identify any wetland areas or streams within or adjacent to the project site. (Figure 3). SOILS MAPPING A review of the mapping of soil types within the project area completed by the U.S. Soils Conservation Service (SCS) identified that the onsite soils consist primarily of Evendell -2 Welland/Wildlife Report -00062 . 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 13 Alderwood gravelly sandy loam (Soils Survey of King County Area Washington, Nov. 1973) (Figure 4). This soil is described as: AgC -Alderwood gravelly sandy loam: This series consists of moderately well drained soils that have a weakly consolidated to strongly consolidated substratum at a depth of 24 to 40 inches. This soil is on uplands and formed in glacial deposits. A typical pedon of Alderwood soils from O -12 inches is dark brown (10YR 4/3) gravelly sandy loam. From 12 to 27 inches the soil is grayish-brown (2.5YR 5/2) gravelly sandy loam with many medium, distinct mottles. This soil series is not listed as a hydric soil. AERIAL PHOTO ANALYSIS Recent aerial photos of the project site were used within the background data collection process. These aerial photos identified that a coniferous forest plant community which has been altered by prior forest harvest actions dominated the majority of the project site. A deciduous forest/shrub community was identified· to pass generally within a narrow corridor north to south through the central portion of the project site. This deciduous forest/shrub community appeared to continue offsite to the south until reaching the top of slope leading in the Green River Valley. A few small pockets also dominated by a deciduous foresVshrubs were present in the north-central and west central portions of the site. The project site was within an area of large-lot single-family homesites and a number of internal roadways were present through the site. ONSITE EVALUATION -WETLANDS WETLAND STUDY METHODS Presently accepted wetland identification is based on a three parameter criteria test as established within both the Corps of Engineers Wetlands Delineation Manual (1987 Manual) and the Washington State. Wetfands Identification and Delineation Manual (Wash. Manual). These criteria are: 1. A predominance of hydrophytic vegetation. 2. The presence of hydric soils, and 3. The presence of wetland hydrology. Initial onsite assessment and evaluation was completed during several site visits in June and July 2000. Specific identification of wetland boundaries was completed on July 17, 2000. Assessment transects were established on a north/south pattern through the project area. Wetland assessment within the project site followed the methods and procedures outlined in both the Wash. Manual and the 1987 Manual. Onsite assessment noted that there were no differences in the identified wetland boundaries as a result to using either the Wash. Manual or the 1987 Manual. Drainage corridors were Evendell -2 Wetland/Wildlife Report. 00062 ' . 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 14 assessed and identified in accordance with the criteria established by King County and the State of Washington Department of Natural. Resources (WDNR) Forest Practice Rules (WAC 222-16-030). The boundary between wetland and non-wetland areas was established by examining the transitional gradient between wetland criteria along transects through the site. Delineation was performed using the routine methodology for areas greater than five acres as detailed in the 1987 Manual. Field data sheets are provided in Appendix A. Identified boundaries were marked in the field with number flagging. These boundaries were then surveyed and made a part of the site plan mapping. FIELD OBSERVATION o Vegetation A mature coniferous forest plant community that had been planted following prior forest harvest actions dominated approximately two-thirds of the project site. The dominant onsite species was Douglas fir (Pseudotsuga menziesi1). These mature trees formed open stands across the treed portion of the site. Additional tree species occurring onsite included Western red cedar (Thuja plicata), Western hemlock (Tsuga heterophylla), big leaf maple (Acer macrophy/lum), red alder (A/nus rubra), black cottonwood (Populus trichocarpa), cherry (Prunus spp), and cascara (Rhamnus purshiana). The understory included a wide variety of shrubs and herb species including vine maple (Acer circinatum), salal (Gaultheria shallon), Oregon grape (Berberis spp.), hazelnut (Cory/us comuta), salmonberry (Rubus spectabilis), Scot's broom (Cytisus scoparius), Himalayan blackberry (Rubus procera), evergreen blackberry (Rubus /aciniatus), Pacific red elderberry (Sambucus racemosa), snowberry (Symphoricarpus a/bus), bracken fern (Pteridium aquilium), and sword fern (Polystichum munitum). Throughout the project site this plant community had been altered by prior forest harvest actions. This plant community was identified as non-hydrophytic (i.e. typical of non-wetlands). The central area of Parcel A was dominated by dense stands of Himalayan blackberry. This area had apparently been cleared of the tree canopy in the recent past, and the blackberry had colonized after the clearing. The plant community within the central drainage corridor (Wetland A) that was identified to generally pass from north to south through the site was dominated by a young, mixed deciduous forest and emergent plant community. This plant community had also been altered by prior forest harvest and grading actions which had removed the mature trees, created slash piles, and created an internal drag-road across this drainage. Observed tree species included sapling red alder, Western red cedar, black cottonwood, Oregon ash (Fraxinus latifolia), and Pacific willow (Sa/ix /asiandra). The understory was dense and included salmonberry, Douglas spiraea (Spiraea doug/asi1), Western crabapple (Pyrus fusee), Sitka willow (Sa/ix sitchensis), slough sedge (Carex obnupta),horsetail Evendell -4 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 15 (equisetum arvensis), buttercup . (Ranunculus repens), reed canarygrass · (Phalaris arundinacea), softrush (Juncus effusus), and lady fern (Athyrium filix-femina). This . plant association was identified as hydrophytic in character (i.e. typical of wetlands). • Soils As identified by numerous sample plots throughout the project site, the majority of 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 3/3) 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. The majority of the project site exhibited soil which would not be considered "hydric." Representative sample plots are identified on Figure 4. (Special note -many more sample plots were completed during the field assessment than are shown within Figure 4 or reported within Appendix A). · Sample plots within the defined drainage corridor that was identified to generally pass from north to southeast through the northeast corner of the site exhibited a mixed gravelly loam soil texture. These soils appeared to be mineral in character. Soils ranged in color from very dark brown (10YR 3/1) to dark grayish brown (10YR 4/2). Redoximorphic features were present and often very prominent. Soils within these areas exhibited "hydric" characteristics. o Hydrology Onsite hydrology appeared to be the result of seasonal stormwater runoff from onsite and adjacent properties. In addition, the pattern of surface water movement appeared to have been modified by prior land use activities. These activities have included the development of offsite homesites, the development of roadways and. utilities, and the placement of culverts. The general movement of surface water runoff across the site was generally to the south. The movement of surface water through the central drainage corridor did not form a continuous drainage pattern and no areas within these swales exhibited characters typical of a "stream." This area had also been impacted by an internal roadway and draglines and logging slash piles. Based on field indicators (i.e. water stained leaves, drift lines, surface water, soil saturation, oxidized root channels, wetland drainage pattern) this drainage corridor met the wetland hydrology criteria of the 1987 Manual and the Wash. Manual. Within an area located in the north-central portion of the site, directly south of the homesite and past the edge of the landscaping, pooled water was also documented. This area was in a small, isolated depression, and had been impacted by prior land use actions (i.e. root pull up, slash pile, compaction). However, based on field indicators (i.e. water stained leaves, drift lines, soil saturation, oxidized root channels, wetland Evendell. 5 Wetland/Wildlife Report • 00062 • 05/10/2004 15:08 2535390514 SDUNDBUILT HOMES PAGE 16 drainage pattern) these isolated depressions met the wetland hydrology criteria of the 1987 Manual and the Wash. Manual. WETLAND AND STREAM DETERMINATION Wetland determination was based on sample plots which contained hydrophytic vegetation, hydric soils. and wetland hydrology in accordance with the 1987 Manual and the Wash. Manual. Based on these methods one wetland area was identified onsite (Figure 4). No area was identified onsite to exhibit characters typical of a "stream" (i.e. a continuous pattern of surface water movement, either permanent or intermittent). WETLAND SIZE ONSITE CLASSIFICATION KING COUNTY FUNCTION STANDARD (square feet) (USFWS) RATING AND VALUE BUFFER . RATING WIDTH A. 17 .162srift PFOE, PEME 2 low 50 feet PFOE palustrine, forested, seasonally flooded/saturated PEME palustrine, emergent, seasonally flooded Wetland A: This wetland was identified within a topographic drainage that passed generally from the central northern boundary to southeast through the northeast corner of the project site. · This wetland complex was dominated by a young, mixed deciduous forest and emergent community that had formed following prior forest harvest and grading activities. This plant community was very dense in the southern end and open on the north end. This wetland complex exhibited shallow ponded surface water during the winter and early growing season as a result of topography, the internal logging road and draglines, a created berm, and an offsite roadway culvert. Soil saturation to the surface was noted to occur within a majority of this wetland complex into the early part of the growing season. As noted by a slash pile within this area forest harvest activities had been undertaken within this wetland complex. This wetland plant community ended adjacent to, but separated from. the roadside berm to 1601h Avenue South to the south. Wetland A was identified to meet the U.S. Fish and Wildlife SeNice (USFWS) criteria for classification as palustrine, forested, seasonally flooded(PFOC) and palustrine, emergent, seasonally flooded/saturated (PEME). Based on the young ·forested plant community this wetland complex was identified to meet the criteria for designation a King County Class 2 Wetland. WETLAND FUNCTION AND VALUE ASSESSMENT Wetlands are known to perform significant roles in the ecosystem, some of which are of immediate value to society. These roles vary greatly with the size, type, hydrology, vegetation, and location of wetland areas. Although the ecological functions performed by this wetland are complex. interrelated, and difficult to assess and quantify, methods Evendell-6 Welland/Wildlife Report -00062 05/10/2004 15:08 2535390514 5DUNDBUILT HOMES PAGE 17 have been developed for the U.S. Army Corps of Engineers (Adamus et al. 1987: Reppert et al. 1979). The functions provided by wetlands include hydrologic support, shoreline protection, stormwater and floodwater storage, water quality, groundwater recharge, and provision of wildlife habitat. The HYDROLOGIC SUPPORT FUNCTION is defined by the measure of hydrologic stability and environmental integrity which the wetland provides. This function is measured by the frequency of inundation and saturation by tidal actions, stream flow, runoff, and precipitation. Wetlands permanently inundated or saturated, or intertidal wetlands are valued as high. Medium valued wetlands are seasonally flooded or are open water systems that remain saturated during most of the growing season. Wetlands that are intermittently flooded or hydrologically isolated are considered of low value. The SHORELINE PROTECTION FUNCTION is defined by the measure of shielding from wave action, erosion, or storm damage which a wetland provides. This function is measured by the location and width of the wetland along shoreline areas, types of vegetation present, and the extent of development along the shoreline. A high value is given to wetlands along a shoreline that have a width greater than 200 yatds and dense woody vegetation. A medium value is given to a wetland with a width of 100 to 200 yards, sparse woody vegetation, and dense emergent vegetation. Wetlands less than 100 yards in width and emergent or lacking vegetation are considered of low value. The STORMWATER AND FLOODWATER STORAGE FUNCTION is defined by the ability of a wetland to store water and retard flow during periods of flood or storm discharge. Wetlands of larger size are generally considered to have greater ability to provide this function. In addition, wetlands nearer to urban or potentially develop-able areas are also considered to provide greater flood protections than wetlands which are in undeveloped areas. The WATER QUALITY FUNCTION is defined by the physical, biological, and chemical processes which wetlands provide to naturally purify water. This function removes organic and mineral particulates through natural filtration. In general, wetlands of greater size, more dense vegetation, and those which are close to point sources of pollution are considered to be of higher value. Wetlands which are small (<5 acres), lacking dense vegetation, and not close to point or non-point sources of pollution are considered of low value. The GROUNDWATER RECHARGE FUNCTION is defined by the interaction of the underlying geology and soils, and the surface topography. This function provides for the movement of surface water into groundwater systems. Important to this function is wetland size, period of inundation, and depth of standing water within the wetland. High value is given to permanently in.undated wetlands greater than 10 acres in size. Medium value is given to wetlands which are Evendell-7 WetlandNVildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 18 seasonally flooded and 5 to 1 O acres is size. Wetlands less than 5 acres in size, isolated, and temporarily saturated are considered of low value. The NATURAL BIOLOGICAL FUNCTION is defined by the complexity of physical habitats and biological species within the wetland area. The value given to a wetland depends upon its ability to provide habitat for nesting (spawning), incubation, feeding, rearing, and cover of aquatic and terrestrial animal and fish species. In addition, the ability of a wetland to provide support for varying food chains is an important element in value assessment. Wetlands of high species diversity, three or more habitat types, unique habitat features, large in size, and . associated with a permanent stream or tidal marsh are considered of high value. Wetlands with moderate species diversity, two habitat types, moderate in size, and associated with an intermittent stream or high salt marsh are considered of medium value. A low value is given to wetlands of low species diversity, small size, and isolated. These six functions are rated low, moderate, or high, based on the criteria outlined above. These criteria are guidelines compiled from Adamus (1987) and Reppert (1979) and professional judgment must be exercised in assessing these criteria. Overall values for a wetland are assigned, based on a synthesis of individual values. In addition to intrinsic functions, extrinsic functions are also recognized. These extrinsic functions provide social values that have indirect benefits to wetlands. Education and recreational opportunities are-most often mentioned as extrinsic functions. Associated values are often subjective and are thus difficult to evaluate. As such, these functions are not rated, but are nonetheless important when considering creation, restoration, or enhancement projects. ONSITE WETLAND VALUATION Following the function and value assessment process noted above Wetland A was rated as exhibiting a low rating: o Water Quality Benefits -This wetland was small, isolated, and had been impacte_d by prior forest harvest and clearing. This wetland appeared to retain less than 25% of the runoff which occurred within the local area. This wetland also exhibited a limited vegetation density as a result of prior forest harvest and grading. The primary water quality benefit provided by this wetland was a very limited amount of biofiltration of surface stormwater. o Stonnwater Storage -This wetland appeared within a topographic depression and had been impacted by prior land uses. This wetland was located in a rapidly developing part of King County. This wetland was small and exhibited a very limited ability to store stormwater. Evendell-8 Wetland/Wildlife Report -00062 05/10/2004 15:08 2535390514 SOUNDBUILT HOMES PAGE 19 o Hydrologic Support -This wetland appeared small, isolated, and to pond a limited amount of surface water early in the growing season. Evidence of seasonal ponding and saturation to the surface was limited. o Groundwater Recharge -This wetland appeared small, isolated, and to pond a limited amount of surface water early in the growing season. Evidence of seasonal ponding and saturation to the surface was limited. o Natural Biological Function -This wetland was small, isolated, and exhibited a very limited range of plant diversity and vegetation complexity. Available habitat was dominated to young deciduous trees. and a dense .shrub community. Unique habitat features (i.e. snags, fallen trees, mature trees along the wetland boundary) were absent. This wetland included a large slash pile resulting from prior forest harvest. ONSITE EVALUATION -WILDLIFE WILDLIFE STUDY METHODS The onsite assessment of wildlife species presence and available wildlife habitats was completed as a part of the onsite assessment of wetland characteristics. This assessment included both early morning and late afternoon observations. Species presence and habitat utilization were evaluated following the methods identified by Horner and Raedeke (1989) and within U.S. Fish and Wildlife Service Publication 80/58 (Mikol, 1980). In addition, the King County Wildlife Study Guidelines (Draft Wildlife Management in King County, Issue Paper, 1993) were also followed to assure consistency with the King County permit process and documentation of habitat types. Onsite activities documented observations of individual species presence, the general location of the species sighting, and the life history activity being undertaken. Sample stations were established within the site for these observations. This range of observations were documented because for many of the smaller, less mobile species (i.e. small mammals, amphibians) the project site may provide all of their life history requirements (nesting, cover, feeding, and reproduction) while for the more mobile species (i.e. waterfowl, songbirds, medium sized mammals) the project site may be used for only a few of the life history requirements. These more mobile species may depend more upon adjacent habitat for more critical habitat needs such as nesting and cover from predators. It is unlikely based upon the existing site conditions. coupled with adjacent land uses, that species which require large areas of undisturbed habitat would exist onsite. Evendell-9 Wetland/Wildlife Report • 00062 05/10/2004 15:08 2535390514 SDUNDBUILT HOMES PAGE 20 ONSITE HABITAT TYPES The site exhibited one primary habitat type that had been manipulated as a part of past land use activities. An upland coniferous forest plant community dominated this primary · habitat type. This plant community had been retained following prior forest harvest activities. Included within this primary habitat type were two additional habitat types. As defined by King County, the "habitat type" best represented within the site was "Conifer Upland Forest -low understory." The primary tree within this habitat type is Douglas fir that is 80 to 200 years old with a well developed understory. One additional habitat type was Persistent Lowland shrub. This upland habitat type has been manipulated and modified by prior forest harvest activities. In parcel B, and in the southern portion of.parcel A, the areas were developed into active pastures, and qualify as Agricultural lands under the County designation. The adjacent properties also exhibited similar land use actions along with the development of single family homesites. The "deciduous forested wetland" habitat type was identified as present within the central drainage corridor (Wetland A). This habitat type had also been impacted by prior forest harvest activities and adjacent land uses. This habitat type included young deciduous trees (i.e. red alder, black cottonwood, Oregon ash, Pacific willow) and a wide variety of shrubs and herbs (i.e. Douglas spiraea, salmonberry, willows, sedges, rushes, reed canarygrass, lady fern, buttercup). PRIMARY HABITAT TYPES INCLUDED IIIIINOR HABITAT TYPES Conifer Upland Forest Deciduous Forested wetland -low understory Aaricultural Lands Persistent Lowland Shrub PLANT AND ANIMAL SPECIES OBSERVATIONS Conifer Upland Forest: The majority of the 14-acre project site was identified to be dominated by a coniferous upland forest plant community. Total crown cover exceeded 60 percent. The primary tree species was Douglas fir that had been retained following prior forest harvest Additional tree species include Western hemlock, big leaf maple, western red cedar, hawthorn, cascara, black cottonwood, and red alder. The understory was dense and composed of a Wide variety of shrubs and herbaceous species. Avian species observed within this coniferous upland forest habitat type included tree swallow (Tachycineta bico/or'), song sparrow (Melospiza melodia), dark eyed junco (Junco hyemalis), American crow (Corvus brachynchos), American robin (Turdus · migratorius), golden crown kinglet (Regulus satrapa), bushtit (Psaltriparus minimus), house finch (Passerdomesticus), Steller's jay (Cyanocitta stellen), pine siskin (Cardue/is pinus), black-capped chickadee (Parus atricapillus}, brown creeper (Certhia americana), ruffed grouse (Bonasa umbel/us), varied thrush (/xoreus naevius), rufous sided towhee (Pipi/o erythrophtha/mus), Northern flicker (Colaptes auratus), and hairy woodpecker (Picoides villosus). These avian species were feeding throughout this Evendell -10 Wetland/Wildlife Report -00062 ~ rt:O!R?.& -~DESIGN Lo4fctf3~ DEVELOPMENT ENGINEER Comments: COMPLETE Date \ Core Design, Inc. 14711 N.E. 29th Place Suite #101 Bellevue, Washington 98007 425.885.7877 Fax 425.885.7963 TECHNICAL :U:NFORMA'fION REPOR'f ('f .:LR.) FOR EVENDELL KING COUNTY, WASHINGTON ' Prepared by: David E. Cayton, P.E. November 8, 2004 04009 Date: Core No.: Revised: December 1, 2004 ~NG/NEERING PLANNING SURVEYING ~ ~Of2Il -~DESIGN King County Department of Development and Environmental Services APPROVAL FOR SITE CONSTRUCTION ~ (z/10/04- Review Engfn ~ ENGACOMP DBtd DEVELOPMENT ENGINEER COMPLETE Date Comments: Core Design, Inc. 14711 N.E. 29th Place Suite #101 Bellevue, Washington 98007 425. 885.7877 Fax 425. 885.7963 LAND USE INSPECTION • SECTJON DECO 2 2004 RECEIVED TECHNICAL INFORMATION REPORT ('f .I.R.) Prepared by: Date: Core No.: Revised: FOR EVENDELL KING COUNTY, WASHINGTON David E. Cayton, P.E. November 8, 2004 04009 December 1, 2004 [ 9.'F.il€.16-i2~ di';;.. :J lt..-1-0'{ .ENGINEER ING Pl ANN I NG 5 UR VE YI NG E.VENDELL TABLE OF CONTENTS I. Project Overview 2. Conditions and Requirements Summary 3. Off-Site Analysis 4. Flow Control and Water Quality Facility Analysis and Design 5. Conveyance System Analysis and Design 6. Special Reports and Studies 7. Other Permits 8. ESC Analysis and Design 9. Bond Quantities, Facility Summaries, and Declaration of Covenant IO.Operations and Maintenance Manual