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Home My WebLink About03396 - Technical Information Report � i r�-� i e.l o� ��-I�'1�r�S m a p� "' Th L ' e and � n g City of Renton, WA _ .. T�CHNICAL INFORMATION REPORT Prepared for . Fairfield Development - Triad ]ob No. 05-071 • • , � _ 3,3 �� The Landing —Technical Information Report • The Landing TECHNICAL INFORMATION REPORT City of Renton, Washington Prepared For: Fairfield Development L.P. 5510 Morehouse Drive, Suite 200 � San Diego, CA 92121 Issued: June 22, 2006 �! Revised: November 7, 2006 Revised: February 2, 2007 Revised: December 19, 2007 �� °FDW 8��GrP Prepared By: �wt� ��a9`� Sheri Murata, P.E. ,� a �O� 8 41846 ,�'�� `�ONA��bti ��°�� Reviewed By: EXPIRES: 11/12/Oq � Mark Reeves, P.E. December 19,2007 � Job#05-071 /T�T p 71 11\lt�lJ SSOCIa'ES � The Landing-Technical Information Report Table of Contents 1 PROJECT OVERVIEW................................................................................... 1-1 Appendlxt................................................................................................................................ 1-3 2 PRELIMINARY CONDITIONS SUMMARY..................................................... 2-1 3 OFFSITE ANALYSIS...................................................................................... 3-1 3.1 Task 1: Study Area Def/nition and Maps....................................................................... 3-1 3.2 Task 2: Resource RevJew...............................................................................................3-1 3.3 Task 3: Fie/d/nspection.................................................................................................. 3-3 3.4 Task 4: Orainage System Descrlptlon and Problem Screening.................................. 3-4 3.5 Task 5: M/tigat/on............................................................................................................ 3-4 Appendlx3................................................................................................................................3-5 4 FLOW CONTROLJVNATER QUALITY DESIGN.............................................. 4-1 4.1 SCSUH/SBUH Method.....................................................................................................41 4.2 ExJst/ng CondiUons.........................................................................................................41 4.3 Proposed Conditlons......................................................................................................42 4.4 Water QualJty Treatment.................................................................................................42 4.5 Detentlon..........................................................................................................................43 Append)x 4................................................................................................................................4-4 5 CONVEYANCE ANALYSIS............................................................................ 5-1 Appendix5................................................................................................................................5-4 6 SPECIAL REPORTS AND STUDIES .............................................................6-1 7 OTHER PERMITS........................................................................................... 7-1 8 TESC ANALYSIS AND DESIGN .................................................................... 8-1 Appendix8................................................................................................................................8-2 9 BOND QUANTITIES, FACILITY SUMMARY AND DECLARATION OF COVENANT ........................................................................................................... 9-1 9.1 Bond Quantities............................................................................................................... 9-1 ' 9.2 Facility Summarles.......................................................................................................... 9-1 9.3 Declaratlon of Covenant................................................................................................. 9-1 Appendix9................................................................................................................................9-2 10 OPERATIONS AND MAINTENANCE .......................................................... 10-1 Appendix10............................................................................................................................ 10-2 , December 19,2007 � Job#05-071 T,o�� The Landing—Technical Information Report 1 PROJECT OVERVIEW The proposed project is the construction of 885 apartments (between Phase 1, the south pazcel and Phase 2, the north parcel), two pazking garages with a total of 1,600 parking stalls, 15,000 SF of retail space and 6,000 SF for a clubhouse/leasing office on approximately 7.8 acres. The construction of a new street, N 10�' Street and the realignment of Logan Avenue N and Park Avenue N will be completed by the City. The site is bounded by Garden Avenue N on the east, Park Avenue N on the west,NE Park Dr on the north and N 10�' Street on the south. It is located in the City of Renton on the south end of Lake Washington. (Refer to the Vicinity Map located below). In general,the site lies within Section 8, Township 23 North, Range 4 East W.M. in King County, Washington. D � I W Z �Cl u�cc ~ w�srrwcrcw z �� tiE ran+sr Sl TE NF 00 RK eo.�r uuna+ �� 0 P A eotx+c p� REN ipN PLANI V� > , -� � �2� 2 2 z y a � � H an+sr 900 ,� � � Q Q � i 8 UEDAR Y � R1YfN �SI lRAK V � � 2 � MUANGPCE N 6lH SI Q A/RPOW! �OAR RIY£R O I �I �1 rrra� � � acHrav Q 1lf4£ORIAL N 5 ST V �P '{ H$STADW4l ��Q. 5 � � �0� 900 �cinitv Man Not to Scale The existing site consisted of an asphalt parking lot scattered with small planter islands. The pavement has since been removed and the site has been cleazed. To the east of the site is another existing pazking lot, a concrete mixing plant, and Fry's Electronics. To the west of December 19,2007 � 1-1 Job#05-071 T7j��j��y�j�J � •ssoci,res � The Landing—Technical Information Report the site is the Boeing Renton Facility. To the south are unoccupied Boeing properties and to the north is Gene Coulon Park. December 19,2007 � 1-2 Job#05-071 T�D A550:1+'ES i� The Landing—Technical Information Report Appendix 9 TIR Worksheet i December 19,2007 � 1-3 Job#05-071 T�� f�SSOCI�TFS / King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner: Project Name: I FF Development L.P The Landing II Address Location: I 5510 Morehouse Drive. Suite 200 Township 23 N i� San Diego, CA 92121 Range 5 E �', Phone: Section 8 ! �858)457-2123 j Project Engineer: � Mark Reeves, PE , Company: Triad Associates '' Address/Phone: 425-821-8448 '� Part 3 TYPE OF PERMIT part 4 OTHER REVIEWS AND PERMITS ' APPLICATf ON ' ❑ Subdivision ❑ DFW HPA ❑ Shoreline ' ❑ Short Subdivision Management , ❑ Grading ❑ COE 404 ❑ Rockery � Commercial ❑ DOE Dam Safety ❑ Structural Vaults �Other Multi-Familv ❑ FEMA Ffoodplain ❑ Other ❑ COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community Drainage Basin , Lower Cedar Drainage Basin I Part 6 SITE CHARACTERISTICS :, I ' � ' ❑ River ❑ Floodplain ❑ Stream ❑ Wetlands ❑ Critical Stream Reach ❑ Seeps/Springs ❑ Depressions/Swales ❑ High Groundwater Tabie ❑ Lake ❑ Groundwater Recharge ❑ Steep Slopes � Other None Part 7 SOILS Soil Type Slopes Erosion Potential Erosive Velocities Fill N/A N/A N/A Postglacial Sand N/A NIA N/A Postqlacial Silt & N/A N/A N/A � Or4ainic Deaosits N/A N/A N/A Alluvial Sand ❑ Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION /SITE CONSTRAINT � Ch. 3—Offsite Analvsis See Geotechnical Report by Geotech Consultants Inc. ❑ ❑ ❑ ❑ ❑ ❑ Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION � Sedimentation Facilities � Stabilize Exposed Surface � Stabilized Construction Entrance � Remove and Restore Temporary ESC Facilities � Perimeter Runoff Control � Clean and Remove All Silt and Debris ❑ Clearing and Grading Restrictions � Ensure Operation of Permanent Facilities � Cover Practices � Flag Limits of SAO and open space � Construction Sequence preservation areas ❑ Other � Other � Part 10 SURFACE WATER SYSTEM � �� ❑ Grass Lined Channel ❑ Tank ❑ Infiltration Method of Analysis i � Pipe System � Vault(StormFilter) ❑ Depression SBUH ', ❑ Open Channel ❑ Energy Dissipater ❑ Flow Dispersal Compensation/ ❑ Dry Pond ❑ Wetland ❑ Waiver Mitigation of Eliminated Site ❑ Wet Pond ❑ Stream ❑ Regional Storage Detention N�A I � !� Brief Description of System Operation Water puality treatment will be provided by two 3-Cartrid9e �� StormFilter CatchBasin StormFilters will be used for Road A(Private RoadL '� Facility Related Site Limitations I Reference Faciliry Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTSITRACTS ❑ Cast in Place Vault ❑ Drainage Easement ❑ Retaining Wall ❑ Access Easement ❑ Rockery>4' High ❑ Native Growth Protection Easement ❑ Structural on Steep Slope ❑ Tract � Other ❑ Other 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. �� 2/ m�t ��✓ �z/��/o7 Si ned/Date The Landing—Technical Information Report 2 PRELIMINARY CONDITIONS SUMMARY CORE REQUIREMENTS These core requirements are based on the 1990 King County Surface �1Vater Design Manual and the City of Renton amendments. However, the water quality facility has been designed per the 2001 Department of Ecology Stormwater Management Manual far Western Washington. (2001 DOE Manual) Core Requirement 1 —Discharge at the Natural Location The proposed project will continue to utilize the site's current discharge point to Lake Washington via an existing 54"pipe in Garden Avenue to Johns Creek. Core Requirement 2—Offsite Analysis A Level 1 downstream has been completed and is located in Section 3 Core Requirement 3—Runoff Control No detention is required for this project since the receiving water is Lake Washington. More than 5,000 SF of replaced impervious area will be subject to vehicular traffic. Two Catchbasin StormFilters will be used for water quality treatment, even though the replaced impervious area added is less than one acre (See Special Requirement#5: Special Water Quality Controls). Core Requirement 4—Conveyance System All onsite storm drainage systems will be sized to convey the 25-year storm. Core Requirement 5—Temporary Erosion and Sediment Control Best Management Practices (BMPs)t�minimize the transport of sediment to drainage facilities, water resources, and adjacent properties will be implemented for this project. Core Requirement 6—Maintenance and Operation December 19, 2007 � 2-1 Job#05-071 TRIAD � The Landing—Technical Information Report The Water Quality vault will be on private property and therefore privately maintained. Core Requirement 7—Bonds and Liability All drainage facilities will be constructed with the bond and liability requirements of the city of Renton. SPECIAL REQUIREMENTS No Special Requirements are required as part of this project. � . I December 19,2007 � 2-2 Job#05-071 TR�D , ASSOf1AiE5 � The Landing—Technical Information Report 3 OFFSITE ANALYSIS ' 3.9 Task 1: Study Area Definition and Maps The project site is bounded by Garden Avenue N on the east, Park Avenue N on the west and � N l Oth Street (new street to be constructed) on the south. It is located in the City of Renton on the south end of Lake Washington. Currently the site is an asphalt parking lot with a few small planter islands which drains east to a 24-inch diameter pipe and then a 54-inch diameter pipe in Garden Avenue N. T'he pavement has since been removed and the site has been cleazed. Runoff flows north crossing Park Avenue N. and continues along the east side of Lake Washington Blvd. It then flows west under Lake Washington Blvd and the railroad tracks into Johns Creek before flowing through Gene Coulon Pazk and into Lake Washington. This site lies within Basin V in Figure 3.2-2 from the Boeing Renton Comprehensive Plan Amendment EIS. Basin IV and portions of Basin VII mainly consisting of impervious surfaces also flow north into Johns Creek. 3.2 Task 2: Resource Review • Adopted Basin Plans and Finalized Drainage Studies This site is part of the Lower Cedar River Basin Plan which was last updated in January 2001. There are no areas of concern within the North Renton sub-basin of the project. • Basin Reconnaissance Summary Reports See Appendix 3.3 • Critical Drainage Area Maps This site is not within a critical drainage area. • Flood plain/floodway (FEMA) maps The site is within Zone C, which indicates areas of minimal flooding. December 19,2007 � 3-1 Job#05-071 T�D ASSOfIATES _ The Landing—Technical Information Report • Excerpt from Boeing Renton Preliminary Draft EIS dated July 8, 2003 Figure 3.2-2 shows the project site as part of Basin V draining to Garden Avenue N. and north to Johns Creek before discharging to Lake Washington � Excerpt from the Ciry of Renton Comprehensive Plan dated February 20, 1995, amended July 27, 1998 The City of Renton Comp Plan shows the site in the North Renton subbasin. • Sensitive Area Folio o Coal Mine Hazard The site is not within a Coal Mine Hazard o Erosion Hazard The site is not within an Erosion Hazard I o Flood Hazard '� The site is not within a Flood Hazard �II o Seismic Hazard I�' The site is within a Seismic Hazard zone and will be addressed during the i, final engineering for the site. o Landslide Hazard The site is not within a Landslide Hazard. � US Department of Agriculture, King County Soils The soils group is Ur, or Urban Land which means that the"soil has been modified by disturbance of the natural layers with additions of fill material several feet thick to accommodate lazge industrial and housing installations." (King County Soils Map) • Wetland Inventory Maps December 19,2007 � 3-2 Job#05-071 /T�� . , . SSOCI�TES J The Landing—Technical Information Report There are no wetlands in or near the project site. 3.3 Task 3: Field lnspection There were no problems encountered during the resource review. A site visit was completed on September 19, 2005. The skies were partly sunny with an approximate temperature of 70 degrees Fahrenheit. There were no obvious signs of problems such as flooding or erosion during the site visit. Silt and vegetation was observed in culverts prior to discharge into the park area which could limit capacity. However, Table 3.3.1 below surrunarizes drainage problems observed by City staff and Boeing employees. Table 3.3.1 Drainage Problems �; �,>> Park Ave N Flooding observed due to water bubbling up from catch basins. ln 2004 the street was closed for a maximum of 2 hours durin a hea rainstorm. - Boeing Guard Shack Flooding encroached upon the Boeing Guard Shack near the entry gate. This occurred twice last ear in Nov-Dec Johns Creek CulveR The four parallel culverts at the entry and discharge end have been in "full" mode with ve etation and siltation occu in ca aci . In the past there have also been reports of flooding in Gene Coulon Park from Johns Creek. The existing site conditions consist of an asphalt pazking lot with scattered planter islands throughout the area. The site is relatively flat with slopes no greater than 1%. The subsurface conditions consist of 5-15 feet of fill, which is underlain by highly variable, discontinuous layers of soft and loose alluvial and lacustrine soils extending to depths of 40- 110 feet below ground surface. Beneath the soft and loose soils is a dense to very dense sand. The existing site drains east to Garden Avenue N. and flows north where it enters a series of open channels, culverts, and stilling ponds. Table 3.3.2 gives the approximate culvert diameters along the drainage path from upstream to downstream before entering Gene , Coulon Park. December 19,2007 � 3-3 Job#05-071 Ti�l�-�D SSOCIATES �_ The Landing—Technical Information Report Table 3.3.2 Approximate Culvert/Pipe Sizes Garden Ave N North 72" Crossing Lake Washington Blvd West 4-48" 1 —84" Crossing the Railroad West � -72� 2—24" Crossing driveway off Lake Washington Blvd North 3—60"z before Gene Coulon Park South Entrance of Gene Coulon Park North 3 -60"'' �Culvets were not measured,just approximated from a distance Z These Culveu are partially fiiled with silt and should be cleaned out. Once the flows enter Johns Creek it flows in for approximately 1,000 feet in a shallow, five foot wide channel before discharging to the south end of Lake Washington. 3.4 Task 4: Drainage System Description and Problem Screening There are no problems or increased flooding anticipated because there isn't a significant increase in runoff between existing and proposed conditions since the existing site consists mainly of asphalt. Also, some of the existing problems were also eliminated by the 72-inch diameter pipe installed in Gazden Avenue N. All on-site conveyance will also be sized for the 25-year storm. 3.5 Task 5: Mitigation The only mitigation proposed for this project is a wet vault for water quality treatment. December 19,2Q07 � 3-4 Job#05-071 /T�� , . SSOCIaTES � The Landing—Technical Information Report Appendix 3 Site Map w/Property Lines and Topography Map Assessor's Map Basin Reconnaissance Summary Report FEMA Map E.rcerpt from Boeing Renton Preliminary Draft EIS Excerpt from City of Renton Comprehensive Plan Sensitive Area Folio King County Soils Map Wetland Inventory Map December 19,2007 � 3-5 Job#05-071 Ti�l[-�D , SSOfIATES __ i � � �..._x-._�:,:�,., ��. ,�,, ,,,, � i , . �'� ,, o _.i.. . r`r' � 1. � -� `Y. 3 � a=. ��e � � L4�� , : j Y*s��r; ��A3a R � � i c€ ° «� 'V �� _^_. ( �`�` tsR`�� saYi k � �� S �x - .i0"�}� i � � �l,. . •` I. 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RECONNAISSANCE REPORT NO. 13 LOWER CEDAR CREEK BASIN � JUNE I937 Natural Resources and Parks Division and Surface Water Management Division King County, Washington King County F�ecutive Tim Hill King County Council Audrey Gruger, District 1 Cynthia Sullivan, District 2 Bill Reams, District 3 Lois North, District 4 Ron Sims, District S Bruce Laing, District 6 Paul Barden, District 7 Bob Grieve, District 8 Gary Grant, District 9 i DCD�tbment of Public Works P�rl�. Plao�iat and Reaouraa Don LaBelle, Director Jce Nagel, Director Srufaoe Water Managemeot Div�iou Natural R�esouioes and Parl�a Division Joseph J. Simmler, Division Manager Russ Cahill, Division Manager Jim Krs�mer, Assistant Division Martager Bill Jolly, Acting Division Manager Dave Clark, Manager, River � Water Derek Poon, Chief, Resour�ces Planning Section Resouree Section Bill Eckel, Manager, Basin Planning Progam Larry Gibbons, Manager, Project Management and Design Section Cootnbuting Staff Contnbutin6 StafE Doug Chin, Sr. Engineer Ray Heller, Project Manager 8c 'Team L.eader Randall Parsons, Sr. Engineer Matthew Clarfc, Project Manager Andy l,ev�ue, Sr. Engineer Robert R Fuerstenberg. Biologist dt ?eam l.eader Bruce Barker, Engineer Matthew J. Bruengo, Geologist Arny Stonkus, Engineer L.ee Benda, Geotogist Itey Staiger, Engineer Denk Booth, Geologi�t Pete Ringen, Engineer Dyanne Shaldon, Wetfands Biologist Cindy Baker, Earth Scientist Di Johnson, Planning Support Technician Robert Radek, Planning Support Technician Randal Bays, Planning Suppon Technician Fred Bent(er, Planning Support Technician � Coo.Kulting StafE Mark Hudson, Planning Support Technician Sharon Clausen, Plunning Support Technician Don Spencer, Associate Geologist, Earth David Truax, Pl�nning Support Technician Consultants, Inc. Brian Vanderburg, Plsnning Support Technician John Bethel, Soil Scientist, Earth Carolyn M. Byerly, Technic�l Writer Consultonts, Inc. Susanna Hornig, Technicul Writer Virginia Newmon, Graphic Artist Marcia McNulty, Typesetter Mildred Miller, Typesetter Jaki Reed, Typesetter Lela Lira, Of[ice Technician Marty Co�, Office Technician P:CR - - i TABLE OF CONTENTS �II I. SUMMARY 1 II. INTRODUCTION 1 III I ii III. FINDINGS IN LOWER CEDAR RIVER BASIN 2 A. Overview of Basin 2 B. Effects of Urbanization 4 C. Specific Probkms 5 1. Drainage and fiooding probkms 5 2. Damage to property 6 3. Destruction of habitat 6 IV. RECOMMENDATIONS FOR ACTION - 7 A, Reduce landslide hazards 7 B. Reducc erosion aad tlooding 7 C. Prcvent futun erosion and flooding with appropriate analysis, 8 planniag. and policy development D. Stop present (and prevent future) damage to habitat - 8 by addressing specific problems in stream systems V. MAP 11 APPENDICES: APPENDIX A: Estimated Costs A-1 ' APPENDIX B: Capital Improvcment Project Ranking B-1 APPEDDIX C: Detailed Fndings and Recommendations C-1 � ; � I. SUMMP�RY ' The Lower Cedar River Basin, in southwest King County, is unique in i[s development pat- terns and the associated environmental problems that appear throughout the basin. Except for the ciry of Renton and areas on the Cedar River Valley floor, most of the development in the basin has occurred on the upland plateaus. Most of this development is recent and primarily residential. In addition, the plateau is the site of numerous sand and gravel mining operations and, in the southern uplands, an abandoned coal miae. Peat is also being mined north of Otter Lake. In some ereas livestock are being raised on small farms; there are no major crop-retated agricuttural activities in the basin. Tt�e effects of development are most apparent where storm drainage is routed arer the vaUey walLs. Impetviws sur[aoes oa t6e platean 6a�e � tbe zate aod volume of abocm tuoot� � i� su6stantial e�osioa. ailtat�oo. and floodio� bclar. In addi- tion, eroeion and �oe �sMc dam�ed oc deatnoyed habitat in maoy t�utariea, threatening the suivival of fish. Habitat and water quality throughout the basin are atso threatened by _ the filting of wetlaada and the presence of i�r�e amoants of domestie 4ash in some atceams. The nconnaissance team noted that the Peterson Creek system has ao far remained in its natural, nesrly pristine condition. Maintaining this quality should be a high priority in future basin planniag capital project programs. ' Recomroendations in the Lawer Cedar River Basia include 1) dc�nin6 and 000atruaing appr�atefy aiaod R/D and aher dninage facilitie� 2) cataMishinE atricter had use poGcie�s regarding floodplains, wetlands, and gravel minia� 3) oonductin6 mon deta�od and oomprehenaiva hydisulic/6y�drnlopc analyses of propo�d developments; and 4) pnventing �e to tbe oatuwl d�nag�e sy� The 6eld team also recommends � �atorio� the 6abitat af a�veral t�ntuies (�.6., cleaning gravels, reve�etating stnam banks, aad diversifying streambeds for spawning and rearing) as well as � praoctina ihe neuty p�i�tiae qnality of Petetaon Crx�. II. �IRODUGTION: Hiatory uod Goals of the Program In 1985 the King County Counal approved funding for the Ptanning Division (naw called the Natural Resources and Parks Division}, in coordination with the Surface Water Manegement Division, to conduct a reconnaisaance of 29 major drainage basins located in King Counry. The effort began with an initial im+estigation of three basins -- Evaas, Soos, and Hyleboa Cneks — in order to determine cxisting and potentiel surface water problems and to recommend action to mitigate and preve�t these problems. These initial investiga- tions used available data end new field observations to examine geology, hydrology, and habitpt conditions in each basin. Findings froro these three basins led the King County Council to adopt Resolution 6018 in April 1986, calling for nconnaissana to be rnmpleted on the remaining 26 basins. Tt�e Basin Reconnaissance Program, which was subsequently established, is now an important ele- ment o[ surface water manegement. The goals of the progrAm are to provide useful data with regard to 1) critical problems needing immediate solutions, 2) basin characteristics for use in the preparation of detailed basin management plans, and 3) capital costs nssociated with the early resolution of drainage and problems. The reconnaissance reports are intended to provide an evaluation of present drainage con- ditions in the County in order to transmit informAtion to policymAkers to aid them in developing more detailed regulatory measures and specific capitel improvement plans. They are not intended to ascribe in any conclusive manner the causes of drainage or erosion P:LC 1 L,ower Ced�r River Basin (continued) problems; instead, they are to be used as initial sunreys from which choices for subsequent - detailed engineering and other professional environmental analyses may be made. Due to the limited amount of time available for the field work in each basin, the reports must be viewed as descriptive environmental aarratives rather than as �nal engineering conclusions. Recommendations contained in each report provide a description of potential mitigative measures for each particular basin; these measures might provide maximum environmentAl protection through capital project construction or developroent approval conditions. The appropriate extent of such measures will be decided on a case-by-case basis by County offi- eials respona�'ble for nwiewing applications for permit appravals and for chooaing aroong competing projects for public construction. Nothing in the reports is intended to substitute for a more thorough environmental and engineering analysis po6sible on a site-specific basis for any proposal. �. FIIVDQIGS IN IAWER CEDAR R[VER BA.SQ�1 The field reconnaissanco of Lower Cedar River Basin was conduct�d in January 1937 by Robert R Fuerstenberg. biologist; Bruce L Barker, engineer, and L.ee Benda, geologist. Their �ndings and recommendations are presented here. A Overvicw o[ L,ow�cr Codar River Basin The lawer Cedar River Basin is located in southw-est King County and is ?7 squAre mites in area. It extends southeast f�om=the mouth of the Cedar River on Lake Washington to approximately river mik 14.0. The boundary to the northeast is marked by a ridgetop connecting the city of Renton to Webst�r and Franklin Lakes; the boundnry co the southwtist n,ns along Petravitslcy Roa�d to Lake Youngs. Renton is thc ortly incorporateQ arta in the basin. Other populfltion centers include Faiiwood, Maplewood Heights, and Mapla Valky. Except for the city of Renton, most of the resideatial concentrations are located on the upland plateaus ovedooking the CCdar River Valley. These upland developmenta are recent compared to the smallcr established mmmunities on the valley floor. The basin lies within portions of three King County planning areas: Nev��c�stk in the northeau (which includes Renton), Tahoma-Reven Heights in the east, and Soos Creek (the largest of the three) in the w�st. Rural areas er.ist on the valley floor on both sides of the Low�er Cedt►r River� [rom - approximately river mile 5.50 to 13.00. These are limited to postureland for horses, cows, And some sheep and several small "u•pick" fruit and ve�tAble [arms. Similar oreas Are located on the southern uptonds ebave the reach [rom river mile 5.50 to 7.00 �nd in the L,�ke Desire-Otter L.�fke ar�a. 'The plateau is also the site of s�nd pnd gr�vel mining operntions and, in the southern uplands, of the obAndonad Fire King Conl Mine. PeAt deposits eaist west of Lake Desiro And nonh and south of Otter Lnke, and peat mining is being carried out north of Otter Lt�ke. Pr�sent zoning allows for urban and suburban densities throughout much of the bosin, p�rticulurly on the uplend plateaus and in the Cedar River VAlley from its mouth to appoaimAtely river mile 6.50. Population projections for the yenr 2000 in the three pinnnign nreus containing the Low�r Cedar BAsin are over 311,000; An incre�se of 47 P:LC 2 . Lo++�er Cedar River Bflsin (continued) percent from the present. Most of this growth w•ill occur in the Soos Creek Planning Area. Dominant goological and seomorphic features. The geology of the Lower Cedar River Basin is diverse. Geological formations exposed along the valley include sedimentary rocks, undifferentiated older glacial dri�t, extensive gmund moraine deposits, rocent alluvium along the Cedar River, and landslide depcuits along the river and its tribu- taries. The sedimentary rocks, composed of moderately dipping sandstones, con- glomerates, mudstones, and shales, are exposed locally along the cliffs of the Cedar River Valley near the mouth of the Cedar River. In addition, the Renton formation, composed of sandstonas, roudstones, and shales with periodic deposits of coal, is also expoaed along the lawer portion of the Lower Codar River Valley. Undifferentiat�d glacial deposits found here art compoaed of three or roore till sheets, glacio-fluviel sand and gravel, glacio-lacustrine clay, and sand, and non-glacial sand, cluy and thin peat. These lie over the sedimentary rocic formations and are best eaposed in cro�.s-section along the clitfs of the main valley and major tributaries. "The morphology of the Lower Cedar River Basin is domina�ed by the valley formed Mr the Codar River. Valky walls an steep cliffs formed by landslides in glacial sedi- � ments. A once extensive and meandering River, which created a wide vallcv floor as it cut its way westv►ard, the Cedar today is diked [or moat of its length through the laver vallry. A narraw but extensive band oi landslide deposits exists along the steep clif[s of the main river and its major tributaries. The landslide dcposits consist of deformed blocks of glacial sediments and colluvium derived From slides or mass flawage, such as landslides and debris flows. Recent alluvial deposits fiU the valley and � major tributaries. Small, composite, alluvial debris fans exist at the mouths ot th� largest tributaries. Closed depressions, principally in the uplands, have lacustrine and peat deposits. The Law�er Cedar Rivcr Valley has a high potential for erosion due to steep slopes and the existence of a clay layer that pmmotes soil failures. [n addition, the confined nature of tributary channels behveen steep hillsloprs promotes bank erosion during high flows. Numerous recent landslides are evident along cli[fs of many of the steep tributaries and along the main stero of the Cedar River. These have been accelernted by the removal of vegetation and the routing of concentratW storm flows over steep slopes in areas where development has occumd. Hydrologic and hydsaulic ebaracteriatics. The Cedar River Basin is composed of a compl�x drninnge netvrrork mnsisting of the CedAr River and 17 tributaries. The Inrger tributaries begin in lakes or wetlends on the bluffs and flow through relatively flut, stable chnnnels to the edge of the Cedar River Valley, then plunge down to the valley floor through steep, erodible mvines. Tributaries of this typ� such ns Tributary 0.'�04 : (with headwaters at Wetland 3111) and Tributary 0323 (which begins at L,�ke Desire), aiti found on the south side of the Cedar River, Another type of tributary collects sutfnce runoff from urbonized �r��s, pF►sturel�nd, and wood�d araas. Tributaries 030� 0307, and 0312 are examples of this type ot tributnry. - They are intermittent (depending on rainfatl), shorter in I�ngth, flow through sht�llower chAnnels thAt are steeper at the bluffs and transport more materi�l during times of P:LC 3 Lower Cedar River Basin (continued) high flaws. Some of the wotst problems located during field investigation (sce Appendix C for a lull listing) occur on this type oF tributary. Catchments 5, 6, and 12 have very iafiltrative soils. Urban developments hvae utilized ; R/D poinds to effectively infiltrate aU urban runoff before it reaches the valley I hillstopes. The infiltrated runoff then reappears as springs. I Two large lakes (Desire aad Otter� together with four smaller ones (Shady, Peterson, Webster, and Franda) lie in the southeaat third of the basin. Numerous large wetland areas exist in thia aectioa sa weU. 'fhe field team identifiod 10 potential wetland sites that had not been previousty tdentified in the Sensitive Areas Map Folio (SAMF). The system of lakea and wetlanda in this area effectivety buffers the high flows draining to these tributaries. Habilat cbaracberistka. With few eaooeptiotu, usable Ctsh babitat exists only in peren- nial streams (i.e., Trib. 0302, 0304, 0305, 0328, and possibty 0308). In other streams (e.g., Trib. 0303 and 0310� steep Sradienta preclude fish use. Steep gradients also reduce fish use ia the perennial systems (except for Trib. 03�). Habitat is in various siages of d�gradation in these systems; pools are being Clled and gravels and debris shift regularly. In Tributary 0328 (Petersoa Crcek� however, habitat diversity is extensive, and the channel is not seriously degraded. At this location the field leam . obsernd at least three species of salmoaoids. In general, the most diverse and least diststurbed habitat in a tributary system occurs in the large w�etland areas in the southeast third of the basin. Usabk habital for anadromous C�sh is found in the low-gradient portions of stceaws where channels cross the Cedar River Valley tloor. In these reaches, hawever, onty spawning habitat is likely to be availeble, as the pools aad woody debris necessary for succe.ssful rearing either do not exisi or are quita limited. Faocellent spav►ming and rearing areas exist where pools and rifflea are extensive, instream caver and bank vegetation are intact, and diversiry of habitat types ia abundant. B. EEfects of Uibaniutioo in tbe Besin Flooding, eroaion, and the degradation of habitat associated with development in the Lower Cedar Rver Basin an most apparent wbere development has eliminated vege- tation along the edges of the valley and where storrowater has been routed down channels and swales. The removal of vegetation, such as trees, abave and below the - edges of valley walLs, as well as the discharging of uormw�ater over the valley wall, has resuhed in tension cracks and landslides that are endangering some houses. The sedi- ments from these failures are depositing in streams and on valley floors and damaging �sh habitat and private property. Discharging stormwater from increased impervious areps into steep tributary channels and swales is seriously destebilizing channels and valley wulls; this in turn results in channel downcutting, bank erosion, and landslides. The sediments from these problems often degrnde Fish habit�t and settle out on pri- vate property along the valley floor. Two serious instances of development•relAted erosion occurred during the November 1936 storm: 1) culverts rerouting the streAm were plugged, causing the formation of a new chennel that destroyed portions of roads on Tributary 0314; and 2) new, uncom- P:LC 4 Lower Cedar River Basin (continued) pacted fill adjacent to new residences near collection point 5 was washed partly away during the storm, causing landsliding and guUying. Future problems wiU be similar to these, as commercial and residential developments increase flow rates and volumes by decreasing natural storage and infiltration. This is eapected to oocur iF wetlands on the upper plateau are encroAched upon or lost (e.g., on Trib. 0304 at RM 2.30 and on Trib. 0304A at Rm 1.60). The presen+ation of wetlands and streambank vegetation and the attenuation of storm flaws are essential in this basin. G Specif'�c Probkms Identified The steep valley sideslopes through which streams pass and the o[ten dense upland development result in a number o[ similar problems that npeat th�mselves throughout the l�ower Cedar River Basin. The most signiCcant o[ these are outlined and discussed below. 1. D:ainage aud floodina probkr� are ofteu t6e n3ult of acv�cral 000ditioo� a Undctsmed culvetia and inadequate entranoe structutes. The most notable area is on Tributary 0306 at river mile .30, where a culven here w-as blocked by debris carried dawnstream by the stream and caused erosion and flooding of Fair+��ood Golf Course. The bbckage was compounded by the fact that the culvert was undersized; the problem will worsen as flows increase from upstream development. b. Setiais instt+cam eivsion aod aubsequeat downstream aodimeotation. These have been caused by three main factors: 1) runoff from residential developmenta on the bluffs above the valley, ?) mmpacted pastureland du� co livestock, and 3) runoff From impervious areas oripnating at gravel pits. These problems will continue and worsen until mitigative measures are taken. (Se�:Appendix C for specific exaroples.) c. Underaized rechannelizod atreams. Tributaries on the vallev floor are too small to carry the increased flows originating in developed residential areas Along the top of the bluffs. For er,ample, Tribwnry 0302 at river mile .25, the channel along Maplewood Golf Course, overtops nnd floods during storms. d. Coaatn�ction in wetland and floodp{ain areas, Many of th� w�etlands on the south side of the Cedar River an peut bog�, and rouds built through them continue to settle each yeAr, increasing the amount of pooding on �he rond. For example, the road crossing with 'Tributary 0323B north of L�►ke Desire will experi�nce more severe flooding as the road settles. e. Discharging of stormwater at t6e top of ateep baaks. At river mile 2.?0 on : the Cedor River, a trniler park (constn,cted on the edge of the cliff) diseherges its drainage dowr the valley w�ll. Incrensed flows erode the � steep valley, depositing sediments on the valley floor, blocking chann�ls nnd cnusing flooding. These problems will eventunlly stabilize, but only nfter a large quantity ot soil has b�en eroded. P:LC S L.ower Cedar River Basin (continued) 2 Damage to propetty ia btiag caused by three facto�a: a Landslides aad potential landslides. Landslides are accelerated by the removal of vegetation on steep slopes in preparation for residentiat I construction and/or by the routing of storm flows over hi{Islopes. For ezample, a Iar�ee landslide has already occurred in the front yard of a resi- dence on the Cedar River at river mile 7.80. I b. Sodimeatatioa (from landslides). Sedimentation end channel and bank ero- sion are damapna privatc property along the valley fioor (Trib. 0299 and I 0310). c. F'loodioa duria6 sforms. Elooding has been bmught on by the effects of davetopment and aasociated changes to the natural drainage systems in the basin. (See 'B" above.) 3_ Datmction of habitat is beins caused by four oonditioos a. Sodimentation of pods and riftks and cementinS of grav�els These problems, the c�esult of severe erosion and the transport of bedload material, have been caused by upland developments in the basin and the � presence o[ associated impeivious surfaces, which increase the rate and quantity of suriace zunoff. Sedimentation and oementing of gravels in streambeds destroy aatural spav�-ning and craring habitat. On Tributary 0307 at river mile .40 and Tributary 0305 at river miles .95, 1.'�0, and 1.70, recent high 8aws have eroded the streambed at least one foot, contributing to a serious siltation problem downstream. Heaw bedload transport is evi- �ient in all systems of the basin except Tributary 0328. In Tributary 0_';03 at river anile �� fine sediments are accumulating in gravels thut may be used by resident fish. In Tributary 0304 between river miles .95 and 1.20, pools aro being Clkd by sends and gravels and rearing habitat is being rapidly lost. b. (�aanalaatioo of atream bocls. Loss of habitat through channelization has occurnd in all the major streams of the basin, but mast noticeably in thosc reaches that cross the valky floor. These reaches lack habitet diversity, reducing fish use for spawning and rearing. Channelization has damaged or destroyed. habitat in several reaches that were on��e heAvily used by fish; � these include Tnbutary 0302 between river mile .'i0 and 40, Tributery 0,'�W between river miles .OS and .18, Tributary 0305 between river mile .30 And .75, and Tributary 0328 from river roile 1.10 to 1.40. These systems �annot ufford a further reduction of habit�t and still remain vi�►ble fishery resour- ces. c. The accumulation of tzas6 in stream bods. This problem occurs in close proximity to residential areas. Trnsh degrades water quality and is visu�lly unpleasant. Tires, appliances, furniture, and other trash have been thrown into Tributarv 030? at river miles 1.00 and 1.10 and in TributArv 0303 at river mile .35. P:LC 6 Lower Cedar River Basin (continued) d Wetland encroacLmeo� Encroachment destroys habitat and elimin�tes natural water filtration and storage for surface runoff. Ex�mples of this problem were observed on Tributary 0304 at river mile 2.30, Tributary 0�03 at .80, and Tributary 0304A at river mile 1.80. Many wetlands have already been completely lost through filling, for example on Tributarv 0306A at river mile .55. Suspected violations werc forwarded to Building and Land Development for enforcement. IV. RF.00�iDATiONS EAOR ACl'ION The primary recommendations for action in the Lawer Cedar River Basin addresses current scwere problems related to erosion, habitat destruction, and flooding. Prevention of ihese problems will be accomplished by controlling locations and densities of new development and providing adequate R/D facilities for stormwater. A. Reduoe landslide 6a�tdt by: 1. Induding seasitiv�e area�t not pnviously mappod ao tLe Seositive A�+eas Map Fo1io (SANQ�} See Appendix C for a full listing of sensitive areas. 2 Eatablishing building setbac�a abnS diffs and native grow�th protection easements along steep ravines. 3. D'tqoo�uraSin� or eliminating the rarting of atotmw�ater w�er difts, unless adequate tightline systems can be constructed to rnnvey flor�s in a safe, nonerosive manncr to the bottom of cliffs. 4. DeQeasin6 pcak Ebwa by constructing target R/D facilities to lessen th� landslide and erasion occurnnce along tributary slopes. B. Reduoc erosion and tlooding in tbe basie by impiwina wrfaoe .vater manaaement: 1. Direc�t the FaNities Maaagemeat 5eetion of tbe Suttaoe Water Maoagement Division to evaluate aosting atorm�etention sod oonveyance fadlities to deter- mine whether they are properly sized to meet curnnt standards. Evaluation should begin with all singlaoriCce R/D facilities. 2 Coasider ar�aa other t6an w�etlaoda aa regiooal atorm-detention facilities. TributAry 0300 at river mile .43 is the site for a pmposed dam, for exnmple. 3. Util'roe e�sting lo�ver qnatity wetlands (those ratod other t6an #1) at regional storm�detentioo fac�ities. Wetlands 3102 and 3142 muld provide more live storage, for exampl�. 4. Review chanael and culvert capacity for oomrying existing and future ruoof[, and establish floodplAin areas in regions of slight grndi�nt for eaisting And future runoff conditions. 5. Prorootc the inf'tltratioo o[ surfeoe water thtougfi the usc of retentioo facilitics and open channeLs inslead of pipat where the soil and slope conditions permit. : Collection points 5, 6, and 12 on plateaus have such soil conditions. P:LC 7 L,ower Cedar River Basin (continued) G Prevent future problema o[ eivsioo and flooding wit6 appropriate analysis, planning, � and poliry ciev�ebpmeat �lated to suifaoe water management: 1. Conduct a detaikd, oomprel�enaiMe hydraulic/hydrologic analY� � �Y ProP�d deeelopmenls to determine impacts on the drain�ge courses downstream. This is especialty critical for areas on the upper bluffs and pla�eau, which drain over steep, sensitive banks above the Cedar River. 2 Cooduet a atu�dp o[ tbe impact of locatins iafiltration ponda utilized near the edge of the bluffa to datermine their effect on seepage facxs on the lawer face of �he btuf[s. This might be aa�omplished with a rnmputer-based numerical model of the groundwater flow. 3. Raryire the te�ttliniu� of ttorm dtainage down stoep or sensitive sbpcs when tbev cannot be dincted away from the slopes. "This is done by piping the flow dawn the slope and discharging it at the bottoro with adequnte energy dissipation. Many of the intermittent tributaries flawing dawn the banks should be tightlined as urban development increases flow ro them. 4. Consttuci oar RJD poods�vith Cdter berms to improMe vratcr quaGry and rodue� fine aediment lo�ds New R/D ponds should have hvo aUs with gravel-berm filters and vegetated svales at the intet and oudet. Consider Tributaries 0304� 0304A, 0302, and 0303 as sites for this type of facility in order enhunce water - quality. S. Mainqin mtunl veSetatioo ou atreaaubaalca and floodplains This is especit�lly important for relativety flat channels flowing on the plateau before they reach the staep bluffs baause thaSe channels and their floodplains will attenuate flo�+s during times of heavy ronoff. 6. Maintain buEfer sreas araund w�etlaads. Many of the tributaries on the south side of the Cedar River headwater at wetlands. These wetlands act as natural stomg� areas during storms. 7. Reevah�ate KinE �otY P�7► ��6 P�rmittin6 for g�avcl mining on steep, sensitive slopea. 8, Indude the city of Rentioa in Euture interfocal agar,ements for planning and capi- - tal improvement projects whera city and county interests overlap. D. Eliminate praent damage to habitat and preveot future damag� by addressing spocific probkms in t6e atream ayatema. The following activities should be coorciinaied among King County, the Muckleshoot Indian Tribe, nnd St�te Departments of Fisheries and Gome: 1. Reduce damaging atotm flowa with gr�ater d�tention volume and lower release rates at upstreAm developmen�s. 2 Impkmeot reatoration projects on Tributnries 0304 (nver mile .00-.20), Tributary 0305 (river mile .20-.80� TributAn� 0303 (river mile .25-.35), and TributAry 03?3 (river mile 1.10 -1.40): P:LC 3 L.ower Cedar River Basin (continued) a. On Tnbutary 0304: Clean streambed gravels, add habitat and bed-control weirs, and plant bank vegetation for shade. b. On Tnbutary QiOd: Construct a new channel and mave stream from road- side channei to its new location on adjacent lands. Implement a full rrstoratioa project to pravide channet meanders, habitat structures, pool/riffle enhancement, streambed gravel replacement, and revegetation. c. On T�ud�y aiO3: Mo�ro atream [rom present channel to a location further north, away from the roadside. It nlocatfon is not possible, these minimum ataps shoutd b� taken: Add habitat structun to existing channel with root maases, detlectors, boulder cluatera, and otder feature� rcvegetate channel _ banka with ahrubs and smap tree� enhance stream crossing,c with bot�omless P�P� arcGea. d. Oa Tnbuta�y Q328 (Pese�soe t�oek� Add habitat structure by roplacing che straight, shortened channel with a more natural, meandering one; place habitat siructnres (such as root masses, deflectors, caver logs, and boulder clusters) througbout the channet; and revegetate banks with shrubs common to adjacent riparian zones (salmonberry, ninebark, or dogwood, for example). 3. Protoct the Petetson Croek syatem (Tnb. Qi28) in ita present, near-priatinc statc. This wil! inetude not only the restoration outlined in section A above, but also the adoptan of Iand use management ngulations to prevent future habitat destruction: s. Protect aU e�w�eWnds w�ithia tbe aubcatchmenta of Petetaoo Geel�. Employ wetland buffers at ksat 100 fcet wide without ezception. b. R�esttict dav�dopment in the aitic�l headovater aa+ea (draio�e, habitat, wrater 9�7) �O� bY � �'R Otter Lake, and Peteraoo Lake bo rurat de�. c. pesi�Oate and proted atrea�ide maoa�ement �ooes of at least 100 feet from the ordinary high-water mark (OHWM) along the main stem of the creek. Use 25 feet from the OHWM on tributaries. d Presern [bodptaias and thdr [oreats for dynamic retention of sediments anC water. a Reatrict vegetation removal in atnamside%retland maaagemeat zones. f. S'iu R/D facilitiea to atore th� 100-year atorm at a two-�o-Gve-yeAr release rate. Use the two-0ell type oE pond with a forebay, a gravel filter, and a vegetnted swale outflaw where feasible. & Regulate more closely a11 aeptic tank and drain-[ield inatapatioos, as well as maintenance schedules, particularly in the Lake Desire, Otter I.eke, and � Peterson Leke drainage areas. P:LC 9 L,ower Cedar River Basin (continued) h. Work with t6e State Department of Eoology to estabtis6 minimum strearo- [law requirements for Pererson Creek and Lake Desire tributary. 4. Dev�elop and promote p�blic �tion and involvement programs for basin awareness. Work with schoola, emironmental groups, and the civic and business communities to mnduct educational and restoration programs. . � P:LC 10 , APPEND[X A � ESTIMATEU COSTS: PROPOSED CAP[TAL JMpROVEMENT PRQTECTS LOWER CEDAR CREGK BA51N " �ndicatas project was 7denutisa by Surfaoa Water Managertient oKce priw to reconnaissanoe_ NOTE: All proje�ts are Iocsted o� map included in this ►epoA. Projcct Collect. Estimatcd Costs Number Point Project Duscription Prol+lem Addressed and Comments 3105• 30 Enhanoe ?�0' of Trih. 0305 from Miti�atas flooding of King 5115,000 Cedar River to Elliot Bridge. County park land. (NOTE: This project was psoposcd by Sur(ace Water Management, is in the design phase, and will be mnstructed by 1489.) 3109' 10 Secuve casements to wettand located Better utilizas wotland's storage $18G,000 in Cascade Park a�d oonstruct a berm capacity to address peak flaws from at the outlet. Replace e�asting surrounding ufian area. catch f+asint with oantrol atructures. Project ishould I�e justified hy a basin study. Wetlancf ratod �2 (Thi�s wetland witl requirc furlhcr biological cvaluation befonc R/D dc�ign and construction.) P:LC.APA A-1 Project Collect. ' Estimated Costs Number Pant Proiecl Descrip�ion Prohlem l�ddn,.�ed and CommCnts 3111 Secure easemcnts to outlet to Fr�ncis Will provide additionai storage 3175,000 (Wetland Lake and 1100' of channel from lake to mitigsttc antic.tipatcd [uture 31:i6) to SE 184th St. (:onstn�ct a weir to incrca�d pows. rnisc lake kv�et 1', and enhance 1100' of Trib. 0317. Should t►e jwstit"�ed by a basin plan. Wctland rated #1. (This wctland will rcquire furihcr biological evaluation heforo R/D d�ign and constroction.) 3113 19 Sccurc eascmcnt for outkt to wetland Will providc additional storagee $117,000 (Wctland and replace existing wcir with a for unticiputed future peak flo�ws. 3143) c�rtcrete-slotted woir. Should be justified by a basin plan. Wetland rnted �?. (Thir, wetland will require furiher biological evalnation betoro R/D design and mnatnuution. 3114' Sccure casement to Wctland 3150 and Addresse� unticiputed increasses in 5134,000 (Wetland con�stnict u oontainment berm and flow causeJ by d�welopment. 3150) control siructuro nt the oudct. Project should be justified�by a , basin plan. Wetland rated �Z ("1'hi.t wetland will r+equire further biologic�l cwaluation l+�[orc; R/D d�ign and con.uruciton.) 3115 18 IauaU detention pond and 1.000' Miti�tes severo crosion and 5361.000 of tightline. Project is indcpen- flooding during times of high dently justifiabk. flows. P:LC.APA A-2 projcct Col�ect. Estimated Ca�ts Numl+cr Point Proicct Dciscription Prot+lem Addreascd and Comments 31Ih 31 Rai4e existing road embankment Miti�tas seasonal flooding of I�ke S7;i,000 ?-4'. Projcct should be indepen- Desire Ur. SE caused by road bed dently jagtiC�at►le. (Refer to settling in the peat bog. Roads Div�sion.) 3117 16 Instalt 1,400' of tightline, a Mitigates severe erosioo. sediments 5501,000 scdimcnt trap, and 700' of channel deposit�:�1 on County roads� and [rom Joncs Rd. to Codar Rivcr. tloocling during times of high Projcct is independcntly justi- [lows. �ablc. 3118 l0 In.stall :;(l0' of 3b" culvert, a new WiU prevent blocka8e of rulvert 537,000 inlet structure, manhok, And catch and tbe aoeompatrying tlooding and bsi.�in. Project is independently erosion of Foinvood Golf Course and ju.stiCabk. mobik home park below. 3119 4 Construct a de�ention dam and Project location i� ideal bu�use 5159,000 control structure in a deep it addreaRes pava from a Iarge channel'vAd section of Trib. reRidential aroa t+efore they reach 0_'i00. Projoct is independently tbe atcep, �nsitive area ncxt to �� justiC�abk. the Cednr RivCr. 31'?0 15 Constn,ct a scdimcntation pond and Miti�tcas Cloocii�g o[ residance And �1G3,000 1,000' of channel from Jon� Rd. to sediment dcpasition on Jones Rd. Ccdar Rivcr. Projcct is indepen- dcntly justiGablc. P:I_C.APA q.3 Project Collect. Estimated Casts Numt+�r Point Proi�ct Description Arobkm Addn..�sseQ and Comments 31�1 � Sccure easement to wetland and con- Addresscs incret�.s�d Fiows in Trib. 5371,000 (Wctland struct a rnntainmem herm and co�crete 0:�04 und 0:�04A from n�idential 3iO3) wc;ir at ouUet. Project sNouki be developments. justified by a basin plan. Wetland ratod �2. E3iolo�ical axsesament is neoded to assure that thix project does not decrease habitat values. 3122 11 Porchase exi�sting ponds on Faitwood Mitigat�s flooding and erasion S34?,000 Golf Course and expand to provide downstream. p+eater pow detention. Project is independeMly justifiable. P:LC.APA A-0 ' I APPENDIX B CAPITAL IMPROVEMENT PROJECT RANKING LOWER CEDAR RIVER BASIN Prior to the Lower Cedar River Basin field reconnaissance, 12 projects had been identified and - ratcd using the C[P selection criteria devetoped by the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Following the reconnaissance, 13 projects remain proposed for this area. They include eight new, previously unidenti�ed and unrated projects. These displace seven previously selected projects, which were eliminated based on the consensus of the recon- nnissance team. Projects were eliminated for several reasons: two sites w-ere annexed by the city of Renton, tv`o projecta were found to be unnecessary, two sites were categoriud as �1 wetlands (and aro'ineligible� and one project was determined to be inf�asible. The previous SWM capital improvement project list for the Lawer Cedar River Basin had an esti- mAted cost of 5�710,000, while the revised Jist increases to an estimated mst of 52,784,000. This 3 . percent increase in estimated capital costs is due to the addition of projccts after the reconnaissance. The follav�ing table summarizes the scores and costs Eor the CIPs propos�d for the Lower Cedar River Basin. These projects were rated acoording to previously established SWM Program �ti�en Advisorp Committee criteria. The projeas ranked below are those for which the Crst rating question. ELEMENT 1: "GO/NO GO," could be answ�ered affirmatively. Projects with scores of 100 or higher can be considered now for merging into the "live' CIP list. RANK PROJECT NO. SCORE COST ' 1 3132 103 5342,000 2 3113 90 87,000 3 31'?0 75 163,000 4 3109' 67 186,000 5 3121 65 371,000 6 3117 60 SO1,000 7 3115 60 361,000 8 3116 55 73,000 9 3114' 28 134,000 10 3111• 25 175,000 11 3112' 17 117,000 12 3119' 15 159,000 13 3105 12 115,000 TOTAL 52,784,000 ` Projects proposed prior ro the Reconn�issance Progrnm ' P:LC.APB B-1 APPENDIX C DETAILED FINDINGS AND RECOMMENDAT[ONS �LOWER CEDAR RIVER BASIN • aD nems �iseea neie s.e �ocaeed on fina dkplar rtmpa in ihe offioes of Surtace Water ManaqMnw�t, &dldiny arW Land Develop��anR ar►d Baei�+ Planning- Trib. & Collect. Existing AnticipatCd Item' River Milc Point Cate�ory Prop. Proi. Conditions and Pcvblems Conditions and Problems Recommeadations 1 -- 5 Geology Gullying and lsindslides in Continued erosion. Recompact fill, revegetate, unoompacted fill in new and drain adequately. dtvelopment near edge of steep hillslope. 2 -- 18 Geology Small landslide has formed None (natural failure). None. debris flow (11/86), Sedimcntation in yard of resideoce. 3 0?99 4 Geology Landslides in sedimcatary Natural failure. None. RM 2.G rodc in cutbanks adjaoent to railroad. 4 0299 16 Geology Drainage from residentia! Increasing erosion. Provide adequatc R/D to RM 9.65 area is c+osulting in attenuate flaws. gullying in swale. P: LC.APC G1 � .. . _.,.�\ I Trib. 8c Collect. Eadstiag Anticipated Item River Mile Point Cat_e�ory Prop. Proi. Coriditions and Problems Conditions and Probkras Recoromendations 5 0299 18 Geobgy Horse farm in uplands has Continued high erosion and Develop R/D at horse farm RM 121 c�eated e�cteasiv�e imper- sedimentation. to attenuate peak flows. vious surfacas, nsulting See Project 3115. in channel soo�ur, bank ero�ion, landslides, and sedimentation at mouth of basin. Residonce overcome with sodiment. 6 — 13 Geology �� terrain for sale Site of future mass emsion. Prohibit dcvelopment here. by realtors. High risk for Notify Building and Land landslidas, flooding (from Developmont. Add area to I spring,$). SAMF. 7 -- 7 Geology Large-scak Iaadsiaes Natural prooess. None. adjaixnt to Cedar River due to springs and cutting of toesbpes by streama Appeara to be na[ural. 8 -- 2 Geology Gutlying in vaUry wall, Unknown. None. poBsibty from natura! springs. 9 -- 14 Geology Landalide debsis flow from Fxi.uing tension etackc Revegetatc hillslope with residence on SE 147th PI., indicate future instebility. trees and shrubs. Renton. P: LC.APC C.2 Tn'b. & Collect. F.�dsti�g Anticipeted Item River Mile Point Cate�oN Prov. Proi. Conditions and Problems Conditions and Probkms Recommendations 10 0299.1A 21 Hydrnlogy 3116 Frequent ftooding of Road located on top of peat Elevate the road 3-4' by RM .08 munty roed cauaed by !ow bog and will oontinue to flling on top of the road embunkment. settle, aggravating flooding prexni road embankment. problem. Also stabilize embankmcnt. 11 0300 4 Gcology F�ctensive channel and Problems will oontinuo. Pravide adequace R/D in RM .00-.4Q bank erosion and numerous uplands. (See Projccc landslidea due to 3119.) dcvebpnunt-nlated stormwatcr. 12 0300 - 4 Hydrology 3119 Developmant-related peak Increased crosion on Construct detention dam in flows have caused sig- hillslopes bebw. deep, channeli�ed reach of nit'kant bank eroaion. Trib. 0300. I 13 0300 4 Hydrology 3109 Collection point 4 has Degradation of Trib. 0300 Constn�ct berm and standard RM 1.40 been nearty mmpletely from RM .42 downst:+sam. Thie oontrol atructure at outlet urbaniud. section is very�ateep and to Wetland 3120 in �',ascade susoeptibk to erosion. Park. 14 0302 6 Geology Channel duwncutting and �ll oontinue at same lavel Coatrol storm flows from RM .50 bank erosion. or increaae. upta�ds. 25 0302 6 Geology Bank erosion (medium den- Increasing erasion wit6 Pravide adequate R/D in RM .80-1.00 sity) at meanders end iacs+oaaing flow from devel- uplanda as area develops. - obatructions. oproents. P: LC.APC C-3 Trib. & Collect. Ezisting Anticipated Item River Mile Point � Prop. Proi. Conditions and Pr'ot�lems Conditions and Probbms Recommendations 16 0_302 6 Geology Gvlly eroaion from broken None. Culvert has bcen None. culverts. repaircd. 17 0302 6 Geology Severe guUy crosion Continued erosion. Tightline 8ows to RM .60-.80 creating small valleys muin stem. from dayligfit cufverts. 18 0.302 6 Habitat Stream channeled plong While fish now usc this Add habitat diversity RM35 golf oourse t+oad. No reach, lack of habitat will (e.g., structures, overhead owrhead cover. No habi- eventually reduoa popula- v�egetation). Gain tat diversity. tions. easement to restore mean- ders, if postible. 19 0302 6 Hydrology Tributary drains down Problem will woraen as Construct detention dam RM .45 ateep bluffs on north development upBtream upstrcam of golf course. side of Cedar RiMer, continues. carrying debris and flooding Maplewood Golf Course. 20 0302 6 Habitat Water supply dam. Full As impoundment fills, stosm- Dradge pond and maintain RM .SO barier to upstream water will floed over bank. it as sodimenc cacch. migratio�. Impoundmcnt Structure may fail. , is 611ing with sodiment. ?1 030? 6 Habitat Severc.gullying from right Will conti�ue to erode until - Tightline downslope. RM .90 bank oorre�ated metal reaches till tayer. - Add velocity attenuator at pipe. Heavy sediment strcam. deliMery to atream. P: L,C.APC C-4 Trib. & Collect. Facisting Anticipated Item Rivcr Mile Point Cat�e ry Prop. ProL Conditiona and Problems Conditions aod Problema Recommendations 22 0302 6 Habitat Trash in strcam (auto, Area adjacent to corridor, - Remove trash. RM 1.00 titcs, appliances). will oontinue to collect - Distribute educational trash and debris. Further materials to streamside worsaning of water qualiry, residents. sedimentation, erosion. - Cite vivlators, if problem Persists• 23 0302 6 Habitat Trash in strcam. Water Area adjacent to oorridor, - Remave trash. RM 1.10 quality pmblem, will cootinue to oolkct - Distribute educational unaightly. trash And debris. Further materials to streamside worsening of water quality. residents. - Cite violatois, if problem persists. 24 0303 6 Geoloay Factenaive bank erosion in Nonc. Increase R/D volumes, slaw relcasc upper portions of tribu- rate to nonerosive levels_ cary. 35 0303 6 Habitat Habitat suitable for resi- Scdiments will eventuslly - Control atormwater volumcs RM .25 dent fjsh. Sediment accu- caver grayelis. Habitat and discharge rates from mulating. will beoomo unsuitabk for devebpments. fiAh uae. - Manually clean gravels whe� necessary. 36 0303 6 Habitat Trash and litter in Further decreases in water - Remove trash and litter. RM 35 channel affecting water quality. - Distributc educational materials quaGty, causing erosion. to streamside residents. - C'ite violators, if problem Persist-�. P: LC.APC GS Trib. & Colkxt. Fxittin� Anticipated Irem Rivcr Mile Point CateLvrv Pt+oA. Proi. Conditions and Prohlems Condieion.s and Probbms Recommendations 27 0_304 7 Habitat Landslides contributing Sediment will continue to Maintain riparian corridor RM .40 sediment to channel. Heavy entor system until tandslidc with setbadcs at least 50' daposition in pools, at stabilius. from tops of banks. obatructions, even in riffles. 2$ o304 8 Habitat Horses have access to Further decreases in water - Enoourage residents to fence RM 2.10 stream, causing some bank quality, bank erosion likeiy. channal back 1�' from ordinary detesioration and pos.�ibly high-arater mark. affecting water quality. - limit acoess co livwsrock to one or two points along stream. 29 0304 8 Hydrology Floodi�tg eauaed by failing Problem will mntinue until - Problem referred to Main- RM 230 R/D at 176th St. & 146th ouHet structure is tenanoe section of Surface Ave SE modified. Water Managcment Division. 30 0_304 8 Habitat Encroachment oocurring Wetlaod likely to be - Require encroaching �lls RM ?40 along all boundaries of reducod slowly until it is to be removed. this headwater wetland. compktely dest:+ayed. Lo�t - Establish specific buffer of atorage, �Itration, around this wctland. organic produetion, and - Enforce sensitive areas wildliCe habitat. ordinancas and regula- tions. 31 0.304 7 Gcology Several gullies due to Probtem will oontinue. • Tightline drainage. RM _80 daylight cufverts; a few hav�e rooent Iandalidas. P: L.C.APC C-6 Tnb. & Colkct. Existing ' Anticipated Item River Mile Point Cate�.rorv Pnop. Proi. Conditiais aod Problems ConGitions and Problems Recommendations 3? 0_304 7 Habitat Extensive riffle (to RM Gravels risk becoming - Enhance habitat by addi- RM .00 .15. Crcek channeled. No cemented. Few resting areas tion of woody dcbris i❑ woody debris, little bank for upstream migrating fish. stream. vegetation. Steelhead, - Rtvegetate bank. coho spawners here. - Enhanc� pool/riffle rAtio. 33 0304 7 Habitat Debris jam may t+e a Debris witl continue to - Selectivety remov�e debris RM .ZO partial migration barrier. accumulata Channel witt to allow fish passage. ' likely divert or jam will - Scabiliu largc woody fail, re{easing accumulated debris. sediment. 34 0304 7 Habirat Debria jam. Bed drops 3' Debris will oontinue to - Selectively rcmove debris RM .62 over jam and sediment, aecumulate. Channet will to aUav fish passage. forming anadromous likely divert or jsm will - Stabilize largc woody barrier. fail, releasing aavmulatad debris. sediment. 36 0304 7 Habitat Water turbid; oily shean Water quuliry will oontinue - Educau residents about RM .80 and oaor pnsent. Storm to doclina as runoff and haw to maintain water quatity. dreins empty directly into waate anter stream. • Mark storm drains with stream. "Dump no oil" si�ns. - Emphasize recycling of oil. 37 0304A 7 Iiydrology 3102 Fxiating forested wetland Additional storag+e could be Construct a proportional weir RM 130 pro�+ides detention for utiliud by conatructing and bcrm at wetland outlet. Trib. 0304A and 0304 in becm and weir at outlet. Project could be used instead heavity developod area. This could be done to atten- of Projec.K 3107 to rpesern the uate increased peak flows #1 ratea w�ctland (where project as upstream area d�vebps. w�ould be built). P: LCAPC C-7 Trib. & Coilect. Existing Anticipated Item Rivcr Milc Point Cate�orv Ptvp. Proi. Cooditans and Prohlcros Conditions and Problems Reoommendacions 38 0304A 18 Hydrology 3115 Runoff generated on top of Flooding will continue as - Construct detention pond RM .40 bluffs on southwest sidc long as land use remains the at top of bluffs. of Cedar River is causing same on top of bluffs or - Tightline drainage down eevere bank crosion, until mitigating moasures bluffs, rhen channelize ;t tlooding pnd debris flows are taken. Runoff origin- to an existing ditch onto aev�eral residences ates from highly compactod aloag�ide SR 169. of valky floor. pastureland on uplands. - Prev�ent simiiar probiems eLgewhere with lar�d use regulatio�s, including prov"tsions for preservation of vegetation buffers near tops of cliffs. 39 0305 10 Geology Fxtensive bank erosion, Susocptible to increases Attenuate high tlows. pe�rtiy due to subsurface with increasing storm tlow. clay layer and laodalide ��PoB�PhY• 40 0_'i05 10 Geology Local aevere bank Problam will oontinue. E�dsting rodc-fillcd RM 1.10 ernsion. pbiona are defleccing flow. 41 0_'i0S 10 Geology Extensive chaanel down- Continucd Crosion. Attenuate high flows with RM ?10. cutting and bank erasion. adequate R/D. (R/D 1.75 � currently exists.) 42 Q'i05 10 Geology Sev�eral guUies and asso- Erosion will coniinuc. TightGne culv�crts. RM 215- ciated laodslides due to 1.75 dayligfit culverts on atcep slopos adjaoent to chan- nels. P: L.C.APC C-8 Trih. & Collect. Fxi�sting Anticipated Item River Mile Point Cu�r_v Pinp. Proi. Conditions and Problems Conditions and Problems Rocommendations 43 030.5 10 I-Iabitat Madsen Crcek in ditch along Potentinl for fuel entry in- Acquire 30' easement away RM .'30 SE Jones Rd. Heavy silt; to creak. Further decreases from roadside. Construcc road runoff; water quality in water quality atn be ea- new stream channel. adversety affected. pected. 44 U305 10 Habitat Creek in ditch along south Further decreases in water Acquirc 30' easomcnt away RM 35 side of SR 169. Heavy quality can be expected. from roadsida Construa inputs of oils, anti- Potential for sutos to enter new stream channel. freezes, heavy metals, channet. Lack of habitat. organic pollutants likely. Sand, silt from roudside (of SR lb9) enters ulso. 45 0305 RM .00- 10 Hydrology 3105 Section of Trib. 0305, Flooding will continue. Construct and enhance ?�00' of .40 RM .00-.40 is experiencing (Sae Appondix A, Projoct channel through uodcveloped ' extensive flooding. 3105.) King County Park Land. 46 0305 10 Habitat Channeliud along dri- Further siltation, water Aoquire tasamenr move RM .50 vaway, lacks hubitat quality dc�radation can be crxk fran driveway diveraity. Driveway sscdi- anticipated. L,adc of habitat 10-15'. Add meanders and menta enter channel, and � procludos optimum seltnonid habitat structures to oil plaeed on drivewny use. increase divcrsity. entens stream. 47 0305 10 Habi[at Channelized tributs►ry Little salmonid asc Add structures to increax RM .6S lacks habitat diversity, anticiputod. Spawning And diversity in stream. cover for satmonids. rearing success limited Manually clean gravels by Gravels mmpacted. (unless reach is restored). churning them. P: LC.APC C-9 Trib. & Collect. Fxisting Anticipated Item River Mife Point C'.ate�orv Prov. Proi. Conditiorus and Problems Conditions and Problems Rocommendations 48 0305 10 Habitat Good apswning riffies occur Increased flows may cause Control flaws into system RM .9d here. Vr-3' gwvets, faw gravcl bar mavcmant. fivm devclopcd arcas fines. not c�ompect. High Suitabk gravels may be upstream. If necessary, flawis are moving material, tran&poried davnatc+eam to add bed oontrols to hold however. unwsable areas for spawning grav�els or 'Wee" struc- salmonids. tures to recruit them. 49 0:�05 10 Habitat Severe bank cutting and Further em�ion/scouang can Control high flows by RM .95 eroeion occurs hore. Bed be expected. Channel increasing upper basin R/D scauring evident. Reach deterioration will continue. facilities, lowering subject to high, rapid Flows appeat to be ganerated discharge rates to stream. flows. at developments. 50 0305 10 Nabitat Much woody debris Debris jams will oaur with Control upstream flaws RM 1.20 movement and numcrous groater troquency ais flavs with �resater R/D volumc, dcbria jams. Reach is increAse. Sediments will lowor discharge rates. subject to fiigh, rapid build up and channel will Sclectively remove debris. [lows. divert. 51 0_';OS l0 Habitat Chant�el ero�ion, bank � Furthcr channel deteriora- - Increase R/D capacity. RM 1.70 failures, downcutting oc- tion may be expectod. Sitt, - Decrease discharge rates. curring. Reach subject to aand trunxport to mairstem high, rapid flaws. will incrcase. 5? 030b 10 Geology Failure of manhole during IYot Applicahle. Repair manhole. RM .40 11/86 atorm has resulted in gully erosion. P: L,C.APC C-10 Trib. & Collect. Exiatiog Anticipated Item River Mile Point C'�te�ory Prop. Proi. Conditions and Problems Conditions and Problcm.4 Recommendations 53 0.306 10 Geology Channel downcuttin�, bank Erossion will inerease. Clay Further increase in ronoff RM .20 eroaion and several layer in valley makes area should be attenuated; this landslides, due both from sensitive to landslides. is a sensitive channel. increased stora� flows and development along edge. 54 0306 10 Geology Undersized eulvert in arti- Possible fiA failure: L.alce Enlarge the corregated RM 30 rcial C�ll in golf course ponded behiad culvert ia metal pipe and/or threstens to build lake and in 1981 and threatened oonstruct adequate trash possibly avertop bank the fU. rack. Brcach flood pc�ssible. 55 0306 11 I�Iabitat Ch�nnel subject to high, Further chaanel damage can Increase R/D capacity, RM ?5 damapng flows. Erosion be expected. Sediment decrease discharge ratc. eviderit. transport dovvnstream will continue. SG 0306 10 Geology Downcutting� bu�k erasion Will continue or increase in Attenuate atorm flows. RM .30-.45 and landslides. future. S7 0_306 Hydrology 3118 Trib. 0306 oonnects with Problem will woraen as - Replace existing pipes RM -30 las�e tributary at manbole devalopmenc upstream with lasgcr d;amecer pipes here. Dcbris from 0.306 mntinues. (if dawnstream analysis cloF,s this manhole, cnusing atlowys for increased flows). severe erosion of Fairwood - Install new inlet struc- Golf Course. tures with trash racks. 58 0306A 11 Hydrotogy 31�2 Existing small ponds on Area upstream is developing - Aoquire easements for ponds RM 130 0306A are overtopped and quickly, thus worseniag the and additional area around ponds reoeive considerable silt problem. and coastruct detention pond. during high flows. The - L,ocation is ideal for addressomg ponds are located on peak flaws before they reach Fainvood Golf Course. the sensitive Cedar Reiver bluffs. P: LC.APC C-11 Trib. & Collect. Existing AntiCipated Item Rivcr Mile Pant Cate�ory Prop. Proj. Conditiot�s and Problems Conditions and Ps+obkms Recommeadatiorts 59 O;OGA 11 Habitat Some uaable habitat exists Further habitat deterioration - Increase R/D capacities. RM � for resident salmonids. likely. Channel erosion will - Decresse discharge rates. Water quality is poor. iocrease. - Encourage use of 2�e11 Channel aubject to high detention ponds, swales. flows. - Prohibit �ping of existiag wetlands, ponds in upper basin. 60 O�i07 1? Geology Extensive bank erosion at increased eroaion wiq - Mitig,ate dtvelopmcnt- RM .10-.40 all meanders and obstrue- result with increased flovvs. rClated high flows. tions (trees, cars) due - Provide adequate R/D. to incraased flows from development. 61 0307 12 Gcology Stream eroding toes of � Inereasing ero�ion with - Mitipte development RM .10-.60 slopes roaulting in ipercasing tlows. related high flows. landslide failures. - Pmvide adequate R/D. 62 0307 12 Habitat Stream channel pushad to Fa+osion witl worsea ss - Inerease R/D capacity at RM 30 0� side of ravine for stream flowa increaee. all delivery points. roa�way. High anergy May threaten road baalc at - Reduce release rate belvw syatem. Much bank cutting, toe of slope. channel scour lev�el. scdimcnt tra�usport, dcbris movement. 63 030'7 13 Hydrology Area on top of bluffs near Infiltration sites shouid Construct retention faci- RM .60 Trib. 0307 bas excxlle�t be uscd whenever poasible. lities for new develop- infiltrative capacity. Tbese would pravido ground- ments in area at these sites. water rechargt. P: LCAPC C-12 Trib. & Collect. Existing Anticipated Item River Mile Point Catefeorv Prop. Proi. Conditioas and Prot+lems Conditions and Proble�as Recommendations I, 64 0309 15 Habitat Subjoct to heavy, rapid Erosion, deposition wiQ - Control storm flows RM .10 flovvs. Channel ei+osion, increase. Scdiments will upstream. deposition bats migration. migrate down�stroam, craating - Control v�olume and discharge a water quality problem. rates. 65 0310 1S Geotogy Sedimentation upstream from Continued sedimentation. - See "Hydrologic and hydraulic RM .60 culvert due to debris and characteristics" section in u�dersi�ed cuivert. New this report. corregated metal pipe con- tinuea to p�ss water through. 6G 0310 15 Goology Severe erosion below ContinurA erosion and - Install energy dissipator RM .OS cutv�ert, aevare sedimen- sedimentation. bolow oornptcd mecal pipe. tation in reaidence yard. - Faccavate cha�nel through yard where origina! channel was locat+ed. 67 0310 15 Geology RAad diainag�e forming gully Continuod erosiqn. Reroute draiaage. Refer probkm RM 1.50 adjauent to road; road bed to Rosds Maintenance. in danger. 68 0310 15 Habitat 31� Corregated metal pipe is Problam will continue. Rei�tall corregated metal RM .2S anadnomous t+arrier. pipe et or below bed level. P: LC.APC C-13 Trib. & Coltcct. Existing � Anticipated Item River Mile Point CatC�ory Prop. Proi. Conditions and Prohlems Conditiorus and Probkms Rernmmendations 69 0310 15 Hydrology 3120 Cxisting channal draining Frcqucnry and scvcriry of Constn�ct detention pond RM .40 of[ bluf(s on north side problem will worsen as on upstream side of Jones o[ Codar River, causing devebpment on bluffs Rd, to trap sediments, and flooding of residences and increases. enhance 1,000' of crcek debris flows onto Jones Rd. from Jonos Rd. to Cedar during peak tlows. River. 70 0310 15 Habitat Corregated metal pipe Problems will mntinue and Remove rtew and old pipes; RM .60 outlet approximately worsen as outfall v�locities replace at lawer level 9' above bed I�wel. will scour bed and banks. with oversized pipe with Compkte barrier to fish. � Upstream has recent (11/36) trash rack. OId culverta at bcd level deposition up to 4' deep. are plug�ed. 71 0311 13 Geotogy Crully eroeion in drainage Continued acaelerated ero- If possibk, enlarge R/D RM 1.70 �wale due to out[low of sion. prior to its outict in thc wetland that partly seems wetland. to act as an R/D facility. 72 0314A 16 Hydrology 3117 Severe erosion, flooding, Problem will be aggravated - Tightline drainage between RM 20 damage to County And as area above develops. deteation ponds in gravel pit. private roads from - Construct detention pond increased runoff from next to Jones Rd. ro trap gravel pit operations on sedimenta. hillaide. - Construct channel from Joaes Rd. to Cedar River. 73 0314A/ 16 Geology Inadequate R/D� pluggad Not appticabla. See hydrology comment 0314Ii culv�ct causod by extcn- above. RM .10..40 siv�e channel and bank eroaioe aad tandslides. Water haa cut a new channel. P: L.C.APC C-14 I I Trib. & Colfect. Fxisting Anticipatcd [tem River Mile Point Caic�orv Prop• Proi. Condidons and Pr'oblems Conditions and Probiems Reoommendations , 74 0317 Hydrology 3111 Francis Lake is only Trib. 0317 Qaws through - Constn�ct proportioeal I RM 1.60 hydraulic control [or steep area downslream of weir at outlet. Trib. 0317. lake. [f area around Francis - Enhana 1,100' from L,ake develops, increasod Francis Lake to SE 184th St. , peak tlows could cause sev�ere ' damage to Trib. 0317 irt the steep regio�. 75 0320 Hydrology 3114 Existing forested wetland if surrounding area uiban- Construct containment berm RM 2.40 with (arge amount of un- izes, this would be a good and control structure at ulilized atorage. Wctland sitc to attenuate peak outlet of wctlaod (if bio- currently destains Claws on flows. logical analysis permics). Trib. 0320. 7G 0318 19 Habitat Ssilmonid parr in many Decroax in water quslity Establish and maintaen RM .]0 pools. Larg�e pools up to with increasing dev�ebp- adequate buffers, 100' 1.75' deep. Somc depoasi- ment. Loss of habitat. from ordinary high-water tion in poola, bchind Decrease in [ish use. mark or 25' from top fo obst�ctions. . slope break, whichever is greater. 77 0�32 19 Habitat Salmonid use apparent from System is mostly in natural - Maintain adequate stream RH( .35 carcasses. Sockeye, mndition. As development mrridor buffers. Chinook apawnerx. Some increase.�, higher flaws and - Reduoe discharge ratcs to sodimentatioo ocrurring. worse water quality can be pre�evebpmenc levels. ezpecteA. Prevent clearing, grading within buffers. P: LGAPC G15 Trib. 8i Collcct. Existing Anticipated Item River Milc Panc Catc�ory Prop. Proi. Gondicions and Problems ConditionS and Probkms Recommendations 7g 03?8 19 Geology Medium-0ensity landslides Nonc. Limit dcvelopment in the RM .50 and high-dcnsity bank basin. erosion occurring due to natural causes. 'I'his indi- cates channel and valley sensitiv�e ro effects of davelopment. (Sensitivity due ro clay layer. Basin hasts some o[ beat fish habitat in upper reaches.) 79 0:;28 19 I�labicat Signi[icant salmonid use ScAimentation from upstream Maintain leave strips RM .70 throughouc. Sockaye reach possibk. Adjacent adjacent to stream at Rpawnera, carcaasea prosent. davelopment will tikely least 100' from ordinary Coho, steelhead parr in reduce divaraity and qualiry high-water mark. Restrict pools. E�ocellent habitat of habitat. uae/dcvelopment within this for apavming and rearing streamside management zone. (a redd site). Much diversity -- mo�t exemplary in basin. Channeliud reach. Uniforcn May cause thermal problems Re.store stream habitat SO 0328 19 Habitat channel, no habitat diver- as water temperatures riee. thraughout: add structure, RM 1.10 sity. Heavy sond deposition. No useful habitat. div�ersity, bank vegetation, 1.40 I�ttk overhead canopy or and canopy. Cosc should be bank vegetation. borne by party(ies) who channelized ihis reach. 81 03?8 19 Hydrology 3112 L,ake Pateison is amall, Lake provides good peak t7ow Replace weir at outlet RM 1.40 open�vater wetland with a attenuution and wiI! beoome with a higher weir in weir at outkt. morc impoRant as upstream ofder to gain additional tributary area develops. storage. P: LC.APC G16 1 KEY TO MAP 500•Year Flood Boundary 100•Year Flood Bou�dary io�e DesiRnatlons+W Ith Due of IdendRcaUon e.g.,12(2/74 100•Ye��Flood Boundary 500•Yenr Flood Boundary B�se Flood Elevatlon Une 513 With Ei�vatlon In feeN• NATIONAI FLOOD INSURANCE PR06RAM Base Flood Elevatfon in Feet 1EL987) Where U�I/orm Withln Zone�• EIev�Uon Referonce Mark RM7X �'�� R{ve►Mlle •M 1.6 �•Reterenced to the Natbn�i Geodetk Vertlpl D�tum of 1929 f 100D INSURANCE RATE MAP •EXPLANATION OF ZONE DESIGNATIONS ZONE EXPIANATION A Areu of 100�year f1ooA; base flood elevations and C1TY OF tlood huud factoR not determined. AO Areas of 100-year shallow floodin6 where depths RENTON, WASHINGTON ire betwan one(1)and throa(3)feet;aven{edepths of Inund�don ore shown,but no flood huard /actors arc determined. KING COUNTY A►, Arou ar ioo-r��• �+�now n�e��g Wh��e a�en: are betwan one (1 j and throe (3) feer base fiood elevatlons arc shown, but no flood huud faeton an determined. A7-A30 Areas of 100-year flood; base flood eleratlons and flood huard fxton determined. PANEL 2 OF 5 A� Areu o� ,00-y��. r�� o be protected by flood protection systam under wnstrocdo�; base flood (SEE MAP INDEX FOR PANELS NOT PHINTED) elevaUOnS �nd flOod haZafd�(ittOR nOt dCIC►ml�Cd. B Areas betwaen Ifmits of the 100-year flood and S00- year flood;or ceruln arou subjeet to 106ysar flood- ing with�veraje depth:less than one(1�foot or whero the cont�ibutin�dralnage area Is less than ona squue mile;or areu protectad by levees trom the base flood. Medlum shadfo C Areos of minim�l flooding.(No shading) D Are�s of undeurtnined, but poulble, ood huards. V Are�s o( lU0-yeir wubl flood with veloclty (w�ve action);bue fiood elevatbns and flood h�:�rd hctors not determined. V7•V30 Areu of 100•ye�r couul flood with vclocity (w�ve acdon);bue flood olev�doAs and flood huard tutors determfoed. COMMUNITY•PANEL NUMBER 530088 0002 B NOTES TO USER EFFECTIYE DATE: �«<�� are�s�ot In the specl�l flood hazard arc�s(zones A�nd V) �uy be protected by flood control structures. MAY5� �98� Th�s m�p !:for flood i�sur�nco purposos only;It does not neces- s�rlly show �II areas sub�nct to flooding In the community or all alanlmetrtc fcatures outsldc speelal flood haz�rd are�s, For qd�olning map panels, see scparatcly printcd Indcx To M�p P�nels. federel emergency management agency I �II federal insurance administration � I � INITIAL IDENTIFICATION: , ,�.�� ` JUNE 7,1974 �� I � I ,.� z � �; � � J i � �� ;- � �� ; ,�� f � �� ,� � , �� ' QOPP� +r� �, P Gj �� .y� 1� , �--�. �/4 � o � \ ,� / Q��f ` � / �'�� ''^\. ; .��; , '.;rF:... ��,��, LAKE � ' WASHI.NGTON '� .�o�' �yG ; ¢�� ' BJ i \ � C � \�N �� pt�7EGT � ��i �` '�� `�\ � �� ,,,� , s�-rE �� \� j' \ cti \�> ��'', � ,� � � i \ Z Z \ ` � \`,\ V� � � zorvEc Q \;� \� u � \\ . , �, �� , ;. ,, t T Q' � \ t �� `� � �'��\ ,� � t �\ �� '� �� N H N S � . 1 _•--•+-+-+ I \�' .i �� \ , � , j , , ,, - _ �- �' LEGEND � F.- _ i'�....v_.--�`" `� � �f �a;�� E A R R � � E h ��9'-�-�'�, ,ti % cw�an. 43� �s ��•k�r� C�is1NA� 8,4SIN �fn . " � a _ C � �"��. - "� � - � � MAJCfl STORM DRNN UNE � m W - � ..� �- '�_ �3�• " � •• ar�iu pE ��+ - � '' -- _ FLOOD PL�IN BOUNOARY � y � c.w�cm: �a�tts eou+o�xr/ � �f..— - - ' cW.w�iwtto.s�rs �y � u r.a n h o�_- - - � � . . aulrx�ys �'� FLOW DIREC110N c y= _ ,,, . cw�oir. a�az �N � G� _ __.�-- ---- -�.�,`--_--" � ��o- � �JO�ES: m° E Q -::_:_.. ' , � �., o �� = �� _ - � 1 ,� BASIN ' �wtt o.e� 1. S£E TAB�� xx FOR SURFACE WAlER �"� –• .:�ti. - -- i ' �� - Oug�ti/6 QUANIITIES FLOVANG TO EACH WTFALL FOR � c.w�am a:� T}{E 6 MONT}i TO 10p YEAR DESIGN STORAIS _ --- � r, � ` > _ qrtFAL� _ . N f�1!" i� �- 1;.} G1PAp1Y:0.5 CfS � _._ s 21' ` � `t i� _ ` ' \ iFAll/B f -" ,� � -'1 �� i GPAQTT: 0.5 CFS i .\,; �i� I��1 � �"^ � {•�� I' ,,y ��' � ' I `' � \ OU1FN1�9 �F i� �� '; _ - I � �— '�, � � BASIN 2 �- �" • ��°'� xa� WA911NGTON I . . - � i .�'�� ti , � All/{C i ; I - I� BASIN 6 _ ;� _ �+ , _ " � ��,� �� i `: � s= au��u r, i `E �;' _ : i _ � " i � , - .. � : CX�OIY: I.f cfT - ' � - - _� - -- ;� - . � _ .. �: � : � ° _ " J ._ . ..f -: _ - - ,- �, �. _. - � - ` ; ,..... _ � _ �ll . .. ' �, : . - , r �� ,r'��AJ. �. � �+. •�� '� �' 1 � i`}"" Y � ; _ ` , ::� c � i - _ \ - � � �� J £.r �� ,, ,~ � �� y,J"' , G /`+�� - � , LOGAN AVE N a�- � - — -- - '� � - �- � t�-� i� �� `!� s.� ' F � s ' ` ; y!� �,� � (�` � ' . .. . . -- _ - " 1 �__ ._ .- . � _ � . . -__.. '. — � _ -- - ... ' � � � . � � :� . BuRN�rrAvE N. ------ _ -.�-_.. .... . _- -�' �' _'`� ',S,'`"� �� - `� N � r: �� -: �— - - _ � _ _ .� _ ��•� �-- BASIN 3 M 3 r ` � ., , r - _. • - , - - -_ -� - ;,� � �` °' t , � � . _ �; ' - ' .: 1? . �:l i.'� ,.�`', ',eb . ouliul p2 � � - � \. � ' � WILLIAMS AVE N � _ - ♦ \ - �s' "' '- ��mr: sc as tL � x � - � �\ ` s' � y i � l/1 - � _- - 'N_�_ a► , -, _ _ � �:. `:. ., �;� c - WELLS AVE N � _ _ � _� ':y,' �:� � ' ' _ _-..:�a: O 200� 400� 800� = - ;. , . 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It Ap2--3 to 8 inches, gray (SY S/1) silty clay '_oum, � s used for pasture. Capability unit IIw-3� light bro:+nish gray (2.5Y 6%2) dry; nany, � r and ciassification. fine, prominent, dark reddish-brown (5YR 3/3 and 3/4) mottles and common, fine, prominent Urban Land mottles of strong brown (7.SYR 5/6) and red- dish yellow (7.5YR 6/6) dry; moderate, fine ; and very fine, angular blocky structure; hard, Urban laz:d (Ur) is soil that has been modified by friable, sticky, plastic; common fine roots; isturbance of the natural layers with additions of inedium acid; abzvpt, wavy boundary. 4 to 6 � ill material several feet thick to accommodate large inches thick. � ndustrial and housing installations. In che Green D21g--8 to 36 inches, gray (5Y S/1) silty clay loaz^, iver Valley the fill ranges from about 3 to more gray (5Y 6/1) dry; common, fine, prominent, han 12 feet in thickness, and from gravelly sandy brown (7.5YR 4/4) mottles and medium, pmmi- oam to gravelly loam in texture. nent mottles of brownish yel.low (lOYR 6/6) dry; The erosion hazard is slight to moderate. No 25 percent of matrix is lenses of very dark � apability or woodland classification. brown (lOYR 2/2) and dark yellowish-brown (lOYR 3/4) peaty muck, brown (7.5YR 4/2) dry; masslve; hard, firm, sticky, plastic; few fine Woodinville Series roots; medium acid; clear, smooth boundary. 30 to 40 inches thick. � The Moodinville aeries is made up of nearly level B22g--38 to 60 inches, greenish-gray (SBG 5/1) silt nd gently undulating, poorly drained soils that loam, gray (SY 6/1) dry; fex, fine, prominent r 'orn�ed �nder grass and sedgas, in alluvium, on stream sottles of brownish yellow (lOYR 6/6) dry; ottaos. Slopes are 0 to 2 percent. The annual massive; hard, very friable, slightly sticky, �recipitation rangas fraa 35 to SS inches, and the slightly plastic; strnngly acid. ,ean annual air temperature is about 50 F. The iost-free season is about 190 days. Elevation The A horizon ranges frow dark grayish brown to •anges from a6out sea level to about 85 feet. gray and fro. silt loaie to silty clay loam. The B In a representative profile, gray silt loam, horizon ranges fron gray and grayish broxn to olive iliy clay loam, and layers of peaty muck extend to gray and greenish gray and from silty clay loam to depth of about 38 inches. This is underlain by silt loam. In places there are thin lenses of very reenish-gray silt loam chat extends to a depth of fine sandy loam and loamy fine sand. Peaty lenses •0 inches and more. are common in the B horizon. These lenses are thin, Woodinville soils are used for row crops, pasture, and their canbined thickness, between depths of 10 .nd urban development. and 40 inches, does not exceed 10 inches. Soils included with this soil in mapping make up nville silt loam (Wo) .--This soil is in elon- no more than 25 percent of the total acreage. Some loc y s aped areas that range from 5 to areas are up to 15 percent Puget soils; some are �p iearly 300 acres in size. It is nearly level and ` to 10 percent Snohomish soils; and some areas are up ;ently undulating. Slopes are less than 2 percent, to 10 percent Oridia, Briscot, Puyallup, Newberg, � Representative profile of Woodinville silt loam, and Nooksack soils. .n pasture, 1,700 feet south and 400 feet west of Permeability is moderately slow. There is a sea- .he north quarter corner of sec. 6, T. 25 N., R, 7 sonal high water table at or near the surface. In •• • drained areas, the effective rooting depth is 60 inches or more. In undrained areas, rooting depth 1p1--0 to 3 inches, gray (5Y S/1) silt loam, grayish is restricted. The available water capacity is brown (lOYR SJ2) dry; coimaon, fine, prominent, high. Runoff is slow, and the hazard of erosion is dark reddish-bro�+n (5YR 3/4) and reddish-brown slight. Stream overflow is a severe hazard unless (SYR S/4) mottles; moderate, medium, crumb flood protection is provided (pl. III, top). structure; hard, friable, sticky, plastic; This soil is used for row crops, pasture, and many fine roots; medium acid; clear, smooth urban development. 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' ft.11FA1.11�N��( � ,� ,� .�� `G � � +': a�► ��i�f��'� �i f�V Jf� �f��i�� t: �I� r re�:•� ib��.� ��j �te .+,�..��.,,� _ „ ,,,.�f ,,�� r ,,, ..�.��',� � �t �� ' ` , � `�, � :,� � ,..�; xE :u�� , ;�► i�ilfli�1c�+.�'/ � ��• _ �t��` w ,;: r �:� �fr� � . . ` �t�i�lffl/t��!��,.��►v��E��.-' � ` � ,,�\�I4�.�i��7 ';;� � �` r -_.1u`•�� 1 et •� �! '�' �.;��U��`d�e*�.:9�A �� h ,'� ��1?tc. _'�� ` '\ � / f'�:a�:.".: � � •. ��4 � .� The Landing—Technical Information Report 4 FLOW CONTROL/WATER QUALITY DESIGN All hydrologic analysis and facility design is based on the 2001 Department of Ecology Stormwater Management Manual for Western Washington, instead of the 1990 King County Surface Water Nlanual as required per the Site Plan Revie�v. 4.1 SCSUH/SBUH Method The Santa Barbara Urban Hydrograph (SBUH) and Soils Conservation Service Unit Hydrograph (SCSUH) method are both based on an SCS Curve Number and use basic SCS equations for computing soil absorption and precipitation excess. The SBUH method however, directly computes a runoff hydrograph without the intermediate step of computing a unit hydrograph. Stormshed software was used for all runoff calculations. � 4.2 Existing Conditions The existing conditions consist of a 7.8 acre asphalt parking lot with several planters II scattered throughout the site. There is existing storm drains consisting of catch basins, pipe and a storm vault. The site is relatively flat with slopes no greater than 1%. Table 4.2.1 shows the existing site conditions and Table 4.2.2 shows the existing 2-yr, 10-yr and 100-yr, 24-hour runoff rates. Table 4.2.1 Existing Landuse Landuse Area(AC) Impervious 7.44 Grass 0.39 Table 4.2.2 Existing Runoff Rates 2-yr 10-yr 100-yr 3.42 5.14 7.03 D,ecember 19,2007 � 4-1 Job#05-071 T�� s�o��.r�, � The Landing—Technicai Information Report 4.3 Proposed Conditions ' The pr.oposed project w-ill construct a total of 885 apartments, 1,600 parking spaces, 15,000 SF of retail, and 6,000 SF for a clubhouse/leasing office. In between the northern and southern complex there will be a vehicle court, serving as the main access points to the parking garages and connect Garden Avenue N and Park Avenue N. Roadway improvements include realigning Park Avenue N and Logan Avenue N. and constructing a new street,N. 10`�' Street which will connect Garden Avenue N. and Park Avenue N. Garden Avenue N will also potentially be widened by four feet. The storm drainage system will consist of catchbasins and storm drain pipe. Runoff from the eastern half of N l Oth Drive will get treated by a StormFilter and discharged to the existing storm drain in Garden Ave N. Runoff from the western half of N l Oth Drive will get treated by a StormFilter and discharged to the existing storm drain in Park Ave N . Table 4.3.1 shows the developed site conditions and Table 4.3.2 shows the developed 2-yr, 10-yr and 100-yr, 24-hour runoff rates. Table 4.2.1 Developed Site Conditions Landuse Area(AC) Impervious 6.77 Grass 1.06 Table 4.2.2 Developed Runoff Rates (Entire site, Phl and Ph2) 2-yr 10-yr 100-yr 3.24 4.90 6.75 4.4 Water Quality Treatment The only area that will be treated is the Private Road (N l Oth Drive). The parking garage tloors will drain to the sanitary sewer, so no stormwater treatment is required. As part of the �ehicle court, 0.53 ac of impervious area and 0.13 ac of pervious area will be added. Two 3- Cartridge StormFilters will be used for water quality treatment. The Stormfilters have each been sized to treat the developed 6-month, 24-hour storm event and have an internal bypass with a m�imum flo�v of 1.0 cfs. For the East StormFilter the 100-year developed storm December 19, 2007 � 4-2 Job#05-071 Ti�1tiD , ASSOCI+TES �� II The Landing—Technical Information Report event is 0.27 cfs and the VVest Storm Filter a 100-year developed storm event is 0.29 cfs so a separate high flo�� bypass ��ill not be necessar}- for either StormFilter. 4.5 Detention No detention is required for this project, since there ��-i11 be direct dischar��e to Lake Vl'ashington. December 19,2007 � 4-3 Job#05-071 TRIAD . , �,-E, �� The Landing—Technical Information Report Appendix 4 Developed Conditions E,rhibit Stormshed Results StormFilter Cost Estimate December 19,2007 � a-4 Job#05-071 TD T n 71 i\lt�1J 5s��,-E� � �� - ... _ _ _, � . . . i �.�.Y / � - . . �,a.�:.��i- . �. e I / � 1 y� 1 U1 � 1'" � , �� : � - „ . 0 �� m / � ��A, r i � N � -�" '� ` �---� t „ ,,./. .��. � I � $ ,�_- , . �-'"' ;,�'� , � , , � � , , e � Y � � � . / I. � a , � �.�.i� � �1. - �I �`_l.r-�'Qm � ` i .. . . . �M' �' I m .,T _�--.. .� - ' i � � � � � 1 � 9� e,� : ,z✓`� _ `:`. � � � � � - , � __ �.,y--�. -�-w��- - �.,,t! ,.� ' � - _ , - � , i"�"� � � �, � = i 1—,r' / x i � I � I , i ��, 1 ; I � � , i � / � � 9I PH 2 I 3.1 AC I _�" J ' � _ ^ � i � ,� � � � :� � \ �'.. A � '�' � � o � � � 8 I � �n � I � �J� I � I � � �I N s W }r ; � � � � g �-� ,;, � � ' � ,! � i � � F � � m x � , i � � � � �� `� \ � � � � i � � � � � �_ � `. � 1'= ' � l � — ---� � / ,�9� a( S. I � �'\ — � — —� —T \ — � '' ''M1 /' � - / /h , � 1 ' � .l N � ? 4� � `t o � '� 1 1 + � �� f ' � - � � , 2_ Y I� � � '� � � � � - � � � s , � . Q ¢ WATER QUAUTY TREATMENT AREA WATER QUALITY TREAT)b/ENT AREA ' � � `� � i � 0.032 AC c� : 0.026 AC �. I il ` �� . � � y� - f � ��y( . .��. : / ,�.' .8 �. �. .�. .. /(/ ti� • -)s. � / 1 4 I � I � PH 1 � 3.1 AC � � � � � ; � � �, I,/ �r� � � f R � / .- � �, '; , , I� � �1 ; ' , � , , � � 0 e ' - � _� —1 — . , .�� - __ �_ ___ . , ' -e � � �� - ; -� __. _ m,` � ,. -— -- „_-� .r , . ,_. ... >.�, . ,. . : . . � r ... � - Y (? � sr ---.- � � ��yT �— ------- _.� � . . . . `_ ' . .`__ � � N ..-------�+'----_'' —r——_ d "`� \"�\`'— � N 10 t TSH R ET (FUTUR 66. z: � 5�� 1 BA�O . _ '�-_��_.. .is+--'.__-�ov�: . o� - ��`- va�OQ —'•e = '� ►----_'__'_� , �_�_�1 -+��_ . . � H . �_ ---� ti_ �-�t— � . . � .. �� . . ' � g � . � � � �` .pt�-,�� . . . � ' - _ . � _+DW'.~-- � i� . � � m � REYRf�BY: D�TC � � �� , �� b � �n �N �' � DEVELOPED CONDITIONS EXH/BlT ` �� & � �� o O �,� � F � � � �� FA/RF/ELD RES/DENTIAL, LLC � �� „ c� �s � THE LAND/NG � �� W CITY OF RENTON, WASH/NGTON Stormshed Summary ' Ex Event Summary �E� ne t Peak Q (cfs)�Peak T (hrs) Hyd Vol (acft) Area (ac) Niethod!Raintype I 6mo �3484 i, 7.83 0.7767 7.8200 SBUH ;TYPE 1 A f I 2 yr 3.4227 7.83 1.1342 7.8200 rSBUH TYPEIA I 5 yr 4.1861 � 7.83 1.3914 7.8200 SBUH TYPEIA 10 yr 5.1364 7.83 j 1.7140 7.8200 SBUH TYPE 1 A I 25 yr 6.0832 7.83 �.0375 7.8200 SBUH TYPEIA �100 yr 7.0274 7.83 � 2.3614 7.8200 SBUH TYPE 1A Record Id: Ex !Design Method SBUH Rainfall type TYPElA jHyd Inri� 10.00 min Peaking Factor 484.00 � Abstraction Coeff 0.2Q Pervious Area (AMC 2) 0.39 ac DCIA 7.43 ac i Pervious CN �90.00 DC CN 98.00 Pervious TC 4.09 min DC TC 4.26 min IPervious CN Calc � Description j SubArea Sub cn I Planters 0.39 ac � 90.00 � Pervious Composited CN (AMC 2) 90.00 Pervious TC Calc I Type Description Length Slope Coeff Misc TT Sheet Smooth Surfaces.: 0.011 20.00 ft 2.00% 0.0110 inoo m�n Sheet Smooth Surfaces.: 0.011 110.00 1.00% 0.0110 ?•00 2.18 � ft �� m min ; , � � Channel Other streams, man-made 425.00 0.50% 0.0120 1.49 � ' (cont) channels and pipe ft ��min � Pervious TC 4.09 min Directly Connected CN Calc � Description SubArea � Sub cn --- ------------- As halt --------_ --- 7.43 ac ------ -_____I I �--- p �----------- ' 98.00 --- ��, � DC Composited CN (AMC 2) j 98.00 III _ ---J i Directly Connected TC Calc � ' Type Description Length i SI po e Coeff Misc TT i - -- - 165.00 r---- - 2 00 3.02 --- ; �Sheet Smooth Surfaces.: 0.011 �ft 1.00%�.0110 in �in I; � - - - � Channel Other streams, man-made 355.00 1.24 ! 0.50% 0.0120 ' (cont) channels and pipe ft � min � Directly Connected TC � 426min � Dev Event Summary Event Peak Q (cfs)iPeak T (hrs) Hyd Vol (acft} Area (ac) Method jRainty ep 6mo 2.2067 � 8.00 0.7450 7.8300 SBUH TYPElA 2 yr �3.2404 � 5.00 1.0975 7.8300 SBUH TYPE 1 A 5 yr 3.9796 _ 8.00 � 1.3523 7.8300 SBUH TYPEIA 10 yr 4.9029 � 5.00 1.6727 7.8300 SBUH TYPEIA � 25 yr 5.8251 8.00 1.9945 7.8300 SBUH TYPEIA 100 yr 6.7458 � 8.00 2.3173 7.8300 SBUH TYPEIA Record Id: Dev �Design Method SBUH �Rainfall type TYPEIA Hyd Intv 10.00 min �Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area (AMC 2) 1.06 ac DCIA �6.77 ac 'Pervious CN 90.00 �C CN 98.00 _ _ _ . _ ____ _ _ _ _ _ _ . Pervious TC 6.30 min DC TC 6.30 min^ Pervious CN Calc Description SubArea Sub cn Planters 1.06 ac 90.00 Pervious Composited CN (AMC 2) 90.00 Pervious TC Calc Type �Description Length Slope Coeff Misc TT -- -- �__. ----- ------- _ - - __ _ -- _ �Fixed �--- -- i -- ----- I6.30 min Pervious TC r 6.30 min Directly Connected CN Calc Description �_- SubArea � Sub cn �'�,I j�-- Asphalt r 6.77 ac �-- - 98.00 ; DC Composited CN (AMC 2) 98.00 ''� Directly Connected TC Calc Type � Description Length Slope Coeff Misc �TT ; Fixed 6.30 min Directly Connected TC 6.30min WQ-To Garden Event Summary Event Peak Q (cfs) Peak T(hrs) Hyd Vol (acft) Area (ac) Method �aintype' 6mo 0.0856 8.00 0.0291 0.3200 SBUH TYPE 1 A �' , 2 yr 0.1275 8.00 0.0433 0.3200 SBUH TYPEIA '' 5 yr 0.1576 8.OQ 0.0536 0.3200 SBUH TYPEIA ' 10 yr 0.1953 8.00 0.0666 0.3200 SBUH TYPEIA 25 yr 0.2330 �8.00 � 0.0797 0.3200 SBUH TYPE 1 A 100 yr 0.2708 8.00 , 0.0928 0.3200 SBUH TYPE 1 A � Record Id: WQ-To Garden Design Method SBUH Rainfall type �TYPE 1 A ; __ _ Hyd Intv 10.00 min IPeaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.07 ac DCIA 0.25 ac 'Pervious CN 90.00 DC CN 98.00 � Pervious TC 6.30 min DC TC 6.30 min � Pervious CN Calc : Description SubArea Sub cn ' ;� Planters 0.07 ac �90.00 � Pervious Composited CN (AMC 2) 90.00 ' Pervious TC Calc --- -------- .---- -- i � Type Description Length �Slope � Coeff � Misc j TT �i � Fixed In Pipe � 6.30 min � i� Pervious TC 6.30 min � � � Directly Connected CN Calc � Description I SubArea � Sub cn � Asphalt � 0.25 ac 98.00 DC Composited CN (AMC 2) � 98.00 - _ . Directly Connected TC Calc _� Type Description Length Slope � C f Misc TT I Fixed Pipe Flow 6.30 min Directly Connected TC 6.30min I WQ-To Park Event Summary Event Peak Q (cfs) Peak T (hrs) Hyd Vol(acft) Area (ac) Method jRaintype 6mo 0.0934 8.00 0.0317 0.3400 SBUH TYPEIA 2 yr 0.1381 �8.00 0.0469 0.3400 SBUH TYPEIA 5 yr 0.1701 8.00 0.0579 0.3400 SBUH TYPEIA 10 yr 0.2102 8.00 �0.0717 0.3400 SBUH TYPEIA 25 yr 0.2503 8.00 0.0857 0.3400 SBUH TYPEIA � 100 yr 0.2904 8.00 0.0996 0.3400 SBUH TYPEIA Record Id: WQ-To Park Design Method SBUH Rainfall type TYPE 1 A Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.06 ac DCIA 0.28 ac I Pervious CN 90.00 DC CN 98.00 Pervious TC 6.30 min DC TC 6.30 min Pervious CN Calc I - --- --- -- -- ---- - -- ------ - -- _ _---- - - _ _ - -- -- --- -- -- ----- - - --- -- --- Planters 0.06 ac � 90.00 I I�' Pervious TC Calc Type Description Length Slope Coeff � Misc �TT Fixed ',In Pipe � �6.30 min � Pervious TC ( 6.30 min i;, _,-I Directly Connected CN Calc 'I Description SubArea � Sub cn �� --'I Asphalt 0.28 ac 98.00 ' DC Composited CN (AMC 2) 98.00 Directly Connected TC Calc ' � Type �escription � Length Slope Coeff Misc TT ' -�� Fixed Pipe Flow � 6.30 min I'I � Directly Connected TC 6.30min 'I'�, Licensed to: TRIAD Associates TESC Event Summarti� , E�t �,Peak Q (cfs) Peak�T (hrs) �,Hyd Vol (acft) �Area (ac) ��ethod Raintype; � 6mo 0.6630 8.13 i 0.3211 7.8000 SCS TYPEIA � � 2 year 1.4373 � 8.11 i 0.5891 7.8000 SCS TYPEIA I 5 year 2.2202 �� 8.11 0.8532 7.8000 SCS TYPEIA �� 10 year 3.0534 � 8.11 1.1320 7.8000 SCS TYPEIA �� 25 year 3.9215 '� 8.09 �1.4207 � 7.8000 SCS TYPE1 A � 100 year 4.8101 8.09 1.7167 � 7.8000 SCS TYPEIA Record Id: TESC Design Method SCS Rainfall type TYPEIA Hyd Intv 10.00 min Peaking Factor � 484.00 Abstraction Coeff 0.20 ' Pervious Area (AMC 2) , 0.00 ac DCIA _ 7.80 ac � - ----� --- -- i Pervious CN � 0.00 DC CN 87.00 ! Pervious TC � 0.00 min �DC TC 21.40 min � ; Directly Connected CN Calc ' � -- -- ---------- � Description , SubArea 'i Sub cn Exposed Soil � 7.80 ac 87.00 � DC Composited CN (AMC 2) �--- 87.00 Directiv Connected TC Calc � ' Type Description Length Slope Coeff Misc � TT Sheet 0.05 W Fields of Loose Soil Surface.: ft 0.00 1.00% 0.0500 n00 mlin 0 �- Directly Connected TC _ _ _ 21.40min I CB Event Summary ��' Event Peak Q (cfs) Peak T (hrs) �Hyd Vol (acft) Area (ac) Method Raintype I �� 6mo 0.1790 8.00 j 0.0608 0.6600 SBUH TYPEIA ; 2 yr � 0.2656 8.00 0.0902 0.6600 SBUH TYPE 1 A � 5 yr 0.3277 8.00 �0.1115 0.660� SBUH TYPE 1 A ' 10 yr 0.4055 8.00 0.1384 0.6600 SBUH TYPEIA j 25 yr 0 4834 8.00 r 0.1654 0.6600 �BUH TYPE 1 A � 100 yr 0.5611 8.00 0.1925 , 0. 66 00 SBUH �TYPE A1 I Record Id: CB I Design Method � SBUH jRainfall type ',r TYPEIA j Hyd Intv 10.00 min Peaking Factor 484.00 ' Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.13 ac DCIA �0.53 ac Pervious CN 90.00 DC CN 98.00 Pervious TC 6.30 min DC TC 6.30 min I' Pervious CN Calc Description SubArea Sub cn '� �- Landscaping 0.13 ac 90.00 Pervious Composited CN (AMC 2) 90.00 � � - - - - -- --— -- ---- _ _ - -- Per��ious TC Calc � � _- —----- --- ! Type Description Length Slope �Coeff ': Misc i TT ' ------ — _ �. Fixed �— � �6.30 min � Pervious TC � 6.30 min � -- — -- - -- ---- . ------- --- - ---- ---- --- _ _ _ ----- '� Directl Connected CN Calc , ), , --- - � Description SubArea � Sub cn Pavement/Side�valk 0.53 ac 98.00 � � --I.._- ------ DC Composited CN (AMC 2) � 98.00 Directly Connected TC Calc , -�--------- ; � Type Description Length Slope Coeff �Misc � TT ' - - -- ------ ---------- Fixed � � �6.30 min �� Directly Connected TC __ _ � 6.30min , Licensed to: TRIAD Associates - -- -- ---- --- ------- - -- - --- - - - - ---- - _ - - --- _ _ -- _ _ _- _ -- �-- -- - - -- Pervious TC Calc -- ---- Type � Description ; Leng h Slope Coeff I 1��1isc I TT �; Fixed I 6.30 min i�� Pervious TC 6.30 min I� -------- -- -- _---- -- � Directly Connected CN Calc '� - - --i I Description SubArea ; Sub cn Pavement/Side��-alk � 0.53 ac � 98.00 DC Composited CN (AMC 2) 98.00 �i . _- - _ _ _ _ I� Directly Connected TC Calc � I �i T p Description i Length Slope Coeff Misc TT � � � � � Fixed � r- �� I 16.30 min ; Directly Connected TC 6.30min i --�---- Licensed to: TRIAD Associates Ph2-Roof Event Summarv Event�Peak Q (cfs) Peak T (hrs) Hyd Vol (acft) Area (ac)��Method �Rainty�pe��; � 6mo 0.9576 8.00 0.319� � 3.1400 � S UB H jTYPE1A � 2 yr 1.3788 � 8.00 0.4642 3.1400 SBUH ;TYPEIA : � 5 yr � 1.6769 8.00 0.5681 � 3.l 400 SBUH TYPE 1 A '� � 10 yr � 2.0472 8.00 0.6983 3.1400 SBUH TYPE I A yr � 2.4158 8.00 0.8286 3.1400 SBUH TYPEIA 25 �� 100 yr 2.7832 8.00 ; 0.9590 3.1400 SBUH �TYPE�l Record Id: Ph2-Roof Design Method SBUH ,Rainfall ty�pe i TYPE 1:� '' Hyd Intv 10.00 min Peaking Factor 484.00 � � Abstraction Coeff r 0.20 Pervious Area (AMC 2) 0.00 ac DCIA 3.14 ac Pervious CN 0.00 DC CN � 98.00 � Pervious TC 0.00 min DC TC 6.30 min � Directiv Connected CN Calc - -- - ------ -- -. ; �—— - - _ _- --------- - ; Description SubArea Sub cn �--------- � � Roof 3.14 ac � 98.00 DC Composited CN (AMC 2) � 98.00 Directly Connected TC Calc y pe � Description � Length Slope � Coeff I�Misc � TT j Fixed Pipe Flo«� 6.30 min i Directly Connected TC �.30min Licensed to: TRI:�D ��ssociates w��%��ewu� ='�'''�'' ' �="- Size and Cost Estimate ^�flRMWATER —� SOLUTIONS iNc. Prepared by Lora Leligdon on January 93, 2007 The Landing — Stormwater Treatment System Renton, WA Information provided: • Garden Avenue N • Total contributing area = 0.32 acre • Impervious area = 0.25 acre • Water quality flow, QWq = 0.09 cfs • Peak hydraulic flow rate, Qpeak= 0.27 CfS • Park Ave N • Total contributing area = 0.34 acre • Impervious area = 0.28 acre • Water quality flow, Qwq = 0.09 cfs • Peak hydraulic flow rate, QPeak= 0.29 Cfs • Presiding agency = City of Renton Assumptions: • Media = ZPG cartridges Per cartridge flow rate = 15 gpm ' Drop required from RIM to outlet = 3.3' minimum Size and cost estimates: The StormFilter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate ' associated with the design storm. The water quality flow rate was calculated by using the SBUH method and provided to CONTECH Stormwater Solutions Inc. ' Garden Ave N ' The StormFilter for this site was sized based on treatment flow rate of 0.09 cfs. To accommodate this ', treatment flow rate, CONTECH Stormwater Solutions recommends using a deep steel three-cartridge �'I CatchBasin StormFilter (see attached detail). The estimated cost of this size system is $13,240, complete and delivered to the jobsite. The contractor is responsible for setting the Catch6asin StormFilter and all external plumbing. The steel CatchBasin StormFilter has an internal bypass capacity of 1.0 cfs, which does not exceed the peak flows from this site. Park Ave N The StormFilter for this site was sized based on treatment flow rate of 0.09 cfs. To accommodate this treatment flow rate, CONTECH Stormwater Solutions recommends using a deep steel three-cartridge CatchBasin StormFilter (see attached detail). The estimated cost of this size system is $13,240 complete and delivered to the jobsite. The contractor is responsible for setting the CatchBasin StormFilter and all external plumbing. The steel CatchBasin StormFilter has an internal bypass capacity of 1.0 cfs, which does not exceed the peak flows from this site. �02006 CONTECH Stormwater Solutions 12021-B NE Airport Way,Portland OR 97220 Page 1 of 1 contechstormwater.com Toll-free: 800.548.4667 Fax:800.561.1271 TS-P026 The Landing —Technical Information Report 5 CONVEYANCE ANALYSIS All conveyance systems are designed in accordance with the 1990 King County Surface Water Design Manual (KCSWDM). Peak flows have been computed using the SBUH method per City direction and conveyance calculations were completed using StormCAD. Structures for pipe systems must be demonstrated to provide a minimum of 0.5' of freeboard between the hydraulic grade line and the top of the structure for the 25-yr peak rate of runof£" The table below shows the tributary area and 25-yr peak draining to each catchbasin that receives surface flows. Please see the Catch Basrn Areas Exhibit at the end of this section. Area Flow Sub Source of Impervious Pervious 25-yr basin Peak Drainage (ac) (ac) cfs CB1A SE quad of R�of 0.79 0.00 0.61 C62 NE quad of Roof 0.77 0.00 0.59 C65 East half of N 0.29 0.07 0.26 10 Dr West half of N C 66 �pm p� 0.24 0.06 0.22 C68 NW quad of Roof 0.90 0.00 0.69 StormCAD was used to determine the hydraulic grade line (HGL) at each catch basin for the 25-yr peak flowrate. For area draining east to Gaxden Ave N, a starting tailwater elevation of 27.25 was used for the backwater analysis. (This was taken from the Final EIS by BHC Consultants in Garden Avenue at the existing catch basin approximately 220' north of the intersection with N 10`� St.) For area draining west to Park Ave N, a starting tailwater elevation of 26.58 was used for the backwater analysis. (Tailwater provided by the City.) The private road (N lOth Drive) ties into two public streets, Garden Ave N to the east and I Park Ave N to the west and is thus constrained by their elevations. The lowest rim elevation on N lOth Drive is 26.60, which is already only 0.02' higher than the starting tailwater elevation in Park Ave N, therefore 0.5' of freeboard cannot be achieved. The hydraulic grade lines takes into account the drainage from the Fairfield site, so there will be slightly more freeboard than what is reported. Please note that the table below summarizes the amount of December 19,2007 � 5-1 Job#05-071 TiV1-1D .SSOCIATES �/ The Landing -Technical Information Report freeboard at the upstream catch basin. Please see the end of this section 1or detailed convevance calculations. Upstream Upstream Upstream Downstream Length Slope Pipe Structure Total Node Node (ft) (ft/ft) Diameter Ground Hydraulic Flow (cfs) Elevation (ft) Grade (ft) CB5 C64 39 0.006 12 inch 27.50 27.30 0.06 CB4 CB3 21 0.005 12 inch 27.60 27.30 0.11 CB3 C62 18 0.006 12 inch 27.70 27.30 0.11 CB2 C61 78 0.005 12 inch 29.00 27.30 0.70 C61A CB1 146 0.006 12 inch 31.00 27.31 0.61 C61 EXCB 47 0.006 24 inch 29.24 27.25 1.88 CB6 C67 42 0.007 12 inch 26.60 26.68 0.22 CB7 C68 12 0.006 12 inch 26.85 26.68 0.22 C68 C69 38 0.021 12 inch 27.08 26.68 0.22 CB9 EXCB#P-21 12 0.084 12 inch 28.33 26.67 0.76 EXCB#P-21 EXCB#P-20 52 0.007 12 inch 27.14 26.64 1.30 The proposed conveyance system will have minor amounts of surcharge at CB7 due to such high initial tailwater condition in Park Ave N. However, if CB6 were to overtop in N l Oth Drive at the intersection with Park Ave N, it will have a safe overflow path. Once the hydraulic grade line lowers, it will eventually drain to the proposed storm system in N l Oth Drive or overflow and drain to the storm drain systems on Park Avenue N. Roof drainage has also been included in the table above. The northeast quadrant discharges to CB2, the southeast quadrant discharges to CB 1 A, and the northwest quadrant discharges to EXCB#P-21. The southwest portion of the roof discharges to CB 10,just south of the retail portion of Phl. With a finished floor of 29.16 and a hydraulic gradeline of 26.4�, there is 2.71' of freeboard, which is more that adequate in the 25-year storm event. Phase 2 Conveyance Using the SBUH method, the roof area of Phase 2 will have a 25-year peak flow of 2.42 cfs, which will be split between CB12 and CB13. CB16 will discharge to SDMH #L-28 on Logan Ave N. The 25-year tailwater elevation at this catch basin is approximately 26.11. A flow of 2.5 cfs will generate a headwater of about 3.96 ft with 2.36' of freeboard, so the connection at CB 12 will have more than enough freeboard in the 25-year storm event. CB 13 will discharge to an existing catch basin on Garden Ave N approximately 100' south from December 19,2007 � 5-2 Job#05-071 T�D ,ss��,E> / The Landing —Technical Information Report the intersection of Garden Ave N and Logan Ave N. The 2�-year tailwater elevation here is approximately 26.59. A flow of 2.5 cfs will generate a headwater of about 2.01 ft with 4.39' of freeboard, so the connection at CB 13 will have more than enough freeboard in the 2�-year storm event. Refer to the Pipe Culvert Analysis in Appendix � for detailed calculations. , December 19, 2007 � 5-3 Job#05-071 'I'i�ll-�D � ♦SS�CIATE� 'I The Landing —Technical Information Report Appendix 5 Catch Basin Areas E�hihit Stormshed Summary Pipe Culvert Analysis— Phase 1 S6��%"Ro��Uutlet Pipe Culvert Analysis—Phase 2 N Roof Oartlet Pipe Cttivert:9nalysis—Phase 2,'�'E Roof Oartlet December 19,2007 � 5-4 Job#05-071 TRIAD �,�!,_�,-�, Stormshed Summary Ex Event Summary Event Peak Q (cfs) �Peak T (hrs) jHyd Vol (acft) �rea (ac) �ethod jRaintype i 6 0 � 2.3484 -- 7.83 ---�---0.7767 7.8200 SBUH rTYPEIA � � 2 yr 3.4227 �7.83 1.1342 �8200 SBUH ;TYPE 1 A ; 5 yr 4.1861 7 83 1.3914 7.8200 � SBUH I TYPE I A � 10 yr 5.1364 ; 7.83 1.7140 �7.8200 ' SBUH TYPEIA ; � �25 yr 6.0832 '� 7.83 2.0375 7.8200 ' SBUH 'TYPE 1 A I , 100 yr� 7.0274 8 2.3614 �7.8200 SBUH TYPE1 A ' Record Id: Ex --- -----� - - -- - rDesign Method SBUH jRainfall type ; TYPE 1 A � Hyd Intv �i 10.00 min Peaking Factor i 484.00 i �- - ; I �Abstraction Coeff 0.20 ;Pervious Area (AMC 2) j 0.39 ac ;DCIA ' 7.43 ac -r-- Pervious CN �90.00 �DC CN i 98.00 ' �--- Pervious TC 4.09 min DC TC � 4.26 min ! Pervious CN Calc ' � Description � SubArea Sub cn �� Planters , 0.39 ac ; 90.00 Pervious Composited CN (AMC 2) � 90.00 �� ---- --- ------- Pervious TC Calc � Type �Description �Length �Slope � Coeff I Misc TT � - r �--- 2 00 0.42 �heet Smooth Surfaces.: 0.011 20.00 ft 12.00% 0.0110 in min i 'Sheet Smooth Surfaces.: 0.011 �10.00 i 1.00% 0.0110 n00 ,mi n 'Channel Other streams, man-made 425.00 � o �� '1.49 (cont) channels and pipe ft 0.50/0 0.0120 min , Pervious TC � 4.09 ! min '; --� Directly Connected CN Calc _i Description SubArea Sub cn � Asphalt 7.43 ac � 98.00 � DC Composited CN (AMC 2) � 98.00 � Directly Connected TC Calc - - _- --- Type Description Length i Slope Coeff j Misc TT ' Sheet Smooth Surfaces.: 0.011 ft�.00 � � i �-- ----- - o ;2 00 3.02 , � � �1.00/0 0.0110 . ' ' �in min i i�Channel Other streams, man-made �355.00 'p.50% �0.0120 I i 1.24 � (_--.------ � �,;(cont) �channels and pipe ,�it ,� ; ;min �. - - ---- __ ___� �I Directly Connected TC ;4.26min Dev Event Summary Event Peak Q (cfs) Peak T (hrs) �Hyd Vol (acft);Area (ac) Method (Raintype� 6mo 2.2067 8.00 0.7450 7.8300 � SBUH ;TYPE 1 A � 2 yr 3.2404 8.00 1.0975 7.8300 SBUH ,TYPE 1 A � 5 yr � 3.9796 8.00 � 1.3523 7.8300 � SBUH �,T EPY lA 10 yr � 4.9029 , 8.00 1.6727 7.8300 j SBUH !TYPEIA � 25 yr ;� � 8.00 1.9945 , 7.8300 SBUH ;TYPE 1 A 100 yr, 6.7458 8.00 i 2.3173 j 7.8300 , SBUH TYPE 1 A 'j Record Id: Dev _ �------ -_ __--- - �Design Method '; SBUH Rainfall type TYPE 1 A �Hyd Intv 10.00 min IPeaking Factor ', 484.00 �-- : , � j Abstraction Coeff j 0.20 , I Pervious Area (AMC 2) 1.06 ac jDCIA � 6.77 ac � I Pervious CN 90.00 IDC CN �98.00 j Pervious TC 630 min jDC TC 6.30 min Pervious CN Calc I Description � SubArea r Sub cn ��I Planters 1.06 ac 90.00 � Pervious Composited CN (AMC 2) 90.00 - II� Pervious TC Calc I; , Type Description Length Slope ! Coeff M s�c TT .__ _------- -- --__- - _-- -- - - --- --- _ - -- i - � - -- --- I --- - - -- _ _ _ _ -- �_ -__ Fixed 6.30 min i� ;i Pervious TC , 6 30 min ; ,! � - -- - -----------:...-_ � Directly Connected CN Calc ----- -- -- --- -- ------- --__ _ _ ; j Description � SubArea j Sub cn ;- ---- ----- --- -- --__ _ _ -- � Asphalt � 6.77 ac - --r- 98.00 ,� DC Composited CN (AMC 2) i 98.00 - - -; -- ---- ------ ----- ------ -----i --- --. ---- --- Directly Connected TC Calc � Type Description Length Slope Coeff ; Misc � TT �� Fixed � � �.30 min Directly Connected TC �6.30min -- � TESC Event Summary � E ev nt ,Peak (cfs) Peak T (hrs) Hyd Vol(acft) Area (ac) Method ;Raintype; � 6mo i 0.6630 8.13 0.3211 7.8000 � CS S �TYPE 1 A I ! 2 year j l.4373 8.11 0.5891 ! 7.8000 '� SCS �TYPE 1 A �'� � 5 year 2.2202 8.11 0.8532 '�. 7.8000 � SCS �TYPE 1 A i 10 year � 3.0534 � 8.11 ; 1.1320 7.8000 ;�SCS jTYPEIA � , 25 year j 3.9215 �8.09 r 1.4207 j 8000 ; SCS ;TYPE 1 A '�100 year 4.81 O 1 8.09 1.7167 � 7.8000 ! SCS 'TYPE 1 A ' Record Id: TESC Design Method SCS �Rainfall type TYPEIA � Hyd Intv 10.00 min IPeaking Factor � 484.00 , ;Abstraction Coeff j 0.20 � jPervious Area (AMC 2) �0 00 ac DCIA 7.80 ac jPervious CN 0.00 DC CN � 87.00 i Pervious TC 0.00 min �DC TC � 21.40 min-I � Directly Connected CN Calc _ Descript�on �SubArea ; Sub cn ; � � Exposed Soil 7.80 ac 87.00 � DC Composited CN (AMC 2) � 87.00 , - ------ ----- _--- _ : Directly Connected TC Calc �Type; Description I Length Slope � Coeff ; Misc � TT � ' S�et Fallo��v Fields of Loose Soil Surface �420.00 1.00% 0.0500 �?-00 �1.40 ,0.05 iit �� !in min ' ' � !,� Directly Connected TC _21.40min �' - -- --___ CB Event Summary Event Peak Q (cfs) Peak T (hrs) Hyd Vol (acft)�Area (ac)iMethod 'Raintype i 6mo r 0.1790 8.00 �0.0608 i 0.6600 � SBUH TYPEIA j ( 2 yr i 0.2656 � 8.00 ( 0.0902 ; 0 6600 ; SBUH TYPE 1 A ',I � ; 5 yr ; 0.3277 � 8.00 0.1115 ; 0. 66 00 ', S UB H TYPEIA I ; 10 yr ; 0.4055 ; 8.00 i 0.1384 �0.6600 � SBUH TYPEIA ! � 25 yr ! 0.4834 ; 8.00 0.1654 0.6600 I SBUH ;TYPEIA 100 yr�0.5611 , 8.00 0.1925 0.6600 j SBUH :TYPE 1 A � Record Id: CB iDesign Method ! SBUH 'IRainfall type j TYPEIA �',Hyd Intv '; 10.00 min iPeaking Factor ' 484.00 � �Abstraction Coeff i 020 '�Pervious Area (AMC 2) � 0.13 ac 'DCIA 0.53 ac ;Pervious CN �40.00 iDC CN j 98.00 Pervious TC 6.30 min jDC TC � 6 30 min ', ----�'. � Pervious CN Calc ; Description SubArea Sub cn i i Landscaping �-0.13 ac � 90.00 Perviaus Composited CN (AMC 2) 90.00 Pervious TC Calc Type ( Description f Len�gth Slope Coeff ; Misc I TT �Fixed , ' �6.30 min � Pervious TC � 6.30 min Directly Connected CN Calc Description SubArea Sub cn _ _ _ _-- - - - - . _ -_ _ � Pavement�'Sidewalk � 0.53 ac � 98.00 DC Composited CN (AMC 2) 98.00 Directly Connected TC Calc �I Type � Description Length Slope � Coeff � Misc � TT -__ __,___ _ __ _ j Fixed � � 6.30 min Directly Connected TC j 6.30min Phl-Roof Event Summary jE nev t!Peak Q (cfs)�Peak T (hrs) IHyd Vol (acft) �;Area (ac) Method �Raintype � 6mo� 0.9637 8.00 � 0.3215 I 3.1600 i SBUH TYPE 1 A ' 2 yr �1.3876 � 8.00 � 0.4672 3.1600 � SBUH i TYPE 1 A ; 5 yr 1.6875 8.00 0.5717 ; 3. 61 00 I-SBUH I TYPE 1 A � yr � 2.0603 � 8.00 �0.7027 3.1600 I SBUH - I 10 ;TYPEIA � 25 yr 2.4312 8.00 �9 3.1600 SBUH TYPE 1 A �100 yr 2.8009 8.00 I 0.9652 3. 61 00 S UB H�TYPE 1 A � - - -- -- - ---- � Record Id: Phl-Roof Design Method ; SBUH �Rainfall type j TYPE 1 A r--- 'Hyd Intv i 10.00 min Peaking Factor 484.00 ! Abstraction Coeff 0.20 � Pervious Area (AMC 2) ��ac ;DCIA 3.16 ac Pervious CN 0.00 DC CN � 98.00 'Pervious TC i 0.00 min DC TC r 6.30 min Directly Connected CN Calc Description � SubArea � Sub cn � Roof 3.16 ac � 98.00 � DC Composited CN (AMC 2) 98.00 �I'! Directly Connected TC Calc � ; Type �Description Length Slope � Coeff Misc TT Fixed Pipe Flow 6.30 min �I Directly Connected TC 6.30min , Ph2-Roof Event Summary �Event Peak Q (cfs) Peak T (hrs) ,Hyd Vol (acft) Area (ac) �Method :Raintype i I 6mo �9�76 08 0 I 0.3195 3.1400 SBUH :TYPEIA ; I 2 yr 1.3788 8.00 ! 0.4642 3.1400 � SBUH 'TYPEIA ; -- -- -- - � 5 yr � 1.6769 � 8.00 0.5681 � 3.1400 SBUH TYPE l A � 10 yr j 2.0472 8.00 0.6983 � 3.1400 � SBUH ;TYPE 1 A � 25 yr ; 2.4158 8.00 j 0.8286 �3.1400 j SBUH j TYPE 1 A � 100 yr� 2.7832 � 8.00 �0.9590 � 3.1400 �SBUH �TYPEIA i Record Id: Ph2-Roof � � --------- iDesign Method I SBUH ,Rainfall type ; TYPEIA ' ;Hyd Intv j 10.00 min Peaking Factor j 484.00 Abstraction Coeff 0.20 ; �Pervious Area (AMC 2) 0.00 ac DCIA 3.14 ac �iPervious CN 0.00 DC CN ��98.00 �' Pervious TC 0.00 min DC TC i 6.30 min -_- -_ j Directty Connected CN Calc ;� Description � SubArea ' Sub cn �� Roof � 3.14 ac ; 98.00 � i � DC Composited CN (AMC 2) 98.00 � � Directly Connected TC Calc ' �-, I Type � Description I, Length � Slope i Coeff ; Misc � TT Fixed Pipe Flow I6.30 min Directly Connected TC �6.30min 'i PH1-SW.txt Phase 1 - sw Roof Quadrant PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE 7anuary 11, 2007 ------------------- PROGRAM INPUT DATA DESCRIPTION VALUE -------------------------------------------------------------------------------- Culvert Diameter (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 FHWA Chart Number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 FHWA Scale Number (Type of Culvert Entrance) . . . . . . . . . . . . . . . . 1 Manning's rtoughness Coefficient (n-value) . . . . . . . . . . . . . . . . . . . 0.012 Entrance �oss Coefficient of Culvert opening. . . . . . . . . . . . . . . . 0. 5 Culvert �ength (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 znvert Elevation at �ownstream end of Culvert (ft) . . . . . . . . . . 21.28 Invert Elevation at Upstream end of Culvert (ft) . . . . . . . . . . . . Z1.35 Culvert slope (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 Starting Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.65 zncremental Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 Ending Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 Starting Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.23 incremental Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0 Ending Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.23 COMPUTATION RESULTS Flow Tailwater Headwater (ft) Normal Critical �epth at outlet Rate �epth znlet outlet �epth �epth outlet velocity (cfs) (ft) Control Control (ft) (ft) (ft) (fps) -------------------------------------------------------------------------------- 0.65 5.23 0.46 5.18 0.28 0.34 1.0 �.83 0.66 5.23 0.46 5.18 0.28 0.34 1.0 0.84 0.67 5.23 0.47 5.18 0.28 0.34 1.0 0.85 0.68 5.23 0.47 5.18 0.28 0.34 1.0 0.87 0.69 5.23 0.48 5.18 0.29 0.35 1.0 0.88 0.7 5.23 0.48 5.18 0.29 0.35 1.0 0.89 0.71 5.23 0.48 5.18 0.29 0.35 1.0 0.9 0.72 5.23 0.49 5.18 0.29 0.35 1.0 0.92 0.73 5.23 0.49 5.18 0.29 0.36 1.0 0.93 0.74 5.23 0.5 5.18 0.3 0.36 1.0 0.94 0.75 5.23 0. 5 5.18 0.3 0.36 1.0 0.95 -------------------------------------------------------------------------------- HYDROCALC Hydraulics for windows, version 1.2 Copyright (c) 1996 �odson & Associates, Inc. , 5629 FM 1960 west, Suite 314, Houston, Tx 77069 Phone: (281)440-3787, Fax: (281)440-4742, Email :software@dodson-hydro.com All Rights Reserved. Page 1 PH2-N.tXt Phase 2 - C612 PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE I 7anuary 26, 2007 I ------------------- PROGRAM INPUT DATA DESCRIPTION VALUE -------------------------------------------------------------------------------- culvert oiameter (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 FHWA Chart Number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 FHWA scale Number (Type of Culvert Entrance) . . . . . . . . . . . . . . . . 1 Manning's Roughness Coefficient (n-value) . . . . . . . . . . . . . . . . . . . 0.012 Entrance �oss Coefficient of Culvert opening. . . . . . . . . . . . . . . . 0. 5 Culvert �ength (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.0 znvert Elevation at �ownstream end of Culvert (ft) . . . . . . . . . . 21.83 znvert Elevation at Upstream end of Culvert (ft) . . . . . . . . . . . . 22.18 culvert slope (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01 starting Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 5 zncremental Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 Ending Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. 5 Starting Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.93 Tncremental Tailwater oepth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0 Ending Tailwater Depth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.93 COMPUTATION RESULTS Flow Tailwater Headwater (ft) Normal Critical Depth at outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocit (cfs) (ft) Control Control (ft) (ft) (ft) (fps� -------------------------------------------------------------------------------- 0. 5 3.93 0.4 3.6 0.24 0.29 1.0 0.64 0.6 3.93 0.44 3.6 0.27 0.32 1.0 0.76 0.7 3.93 0.48 3.61 0.29 0.35 1.0 0.89 0.8 3.93 0.52 3.62 0.31 0.37 1.0 1.02 0.9 3.93 0.55 3.63 0.33 0.4 1.0 1.15 1.0 3 .93 0. 59 3.64 0.35 0.42 1.0 1.27 1.1 3.93 0.62 3.65 0.37 0.44 1.0 1.4 1.2 3.93 0.66 3.67 0.38 0.46 1.0 1.53 1.3 3.93 0.69 3.68 0.4 0.48 1.0 1.66 1.4 3.93 0.72 3.7 0.42 0.5 1.0 1.78 1.5 3.93 0.76 3.72 0.43 0.52 1.0 1.91 1.6 3.93 0.79 3.74 0.45 0.54 1.0 2.04 1.7 3.93 0.82 3.76 0.46 0.55 1.0 2.16 1.8 3.93 0.85 3.78 0.48 0.57 1.0 2.29 1.9 3.93 0.88 3.8 0. 5 0.59 1.0 2.42 2.0 3.93 0.92 3.83 0. 51 0.6 1.0 2. 55 2.1 3.93 0.95 3.85 0. 53 0.62 1.0 2.67 2.2 3.93 0.98 3.88 0. 54 0.63 1.0 2.8 2.3 3.93 1.01 3.9 0. 56 0.65 1.0 2.93 2.4 3.93 1.04 3.93 0. 57 0.66 1.0 3.06 2.5 3 .93 1.07 3.96 0.59 0.68 1.0 3.18 HYDROCALC Hydraulics for windows, version 1.2 Copyright (c) 1996 �odson & associates, Inc. , 5629 FM 1960 west, Suite 314, Houston, Tx 77069 Phone: (281)440-3787, Fax: (281)440-4742, Email :software@dodson-hydro.com Page 1 PH2-NE.tXt Phase 2 - CB13 PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE 7anuary 26, 2007 -------------- PROGRAM INPUT DATA DESCRIPTION VALUE -------------------------------------------------------------------------------- Culvert �iameter (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.83 FHWA Chart Number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 FHWA scale Number (Type of Culvert Entrance) . . . . . . . . . . . . . . . . 1 Manning's Roughness Coefficient (n-value) . . . . . . . . . . . . . . . . . . . 0.012 Entrance Loss Coefficient of Culvert opening. . . . . . . . . . . . . . . . 0. 5 Culvert �ength (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.0 znvert Elevation at Downstream end of Culvert (ft) . . . . . . . . . . 25.6 znvert Elevation at upstream end of Culvert (ft) . . . . . . . . . . . . 25.8 culvert Slope (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0091 Starting Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 5 zncremental Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 Ending Flow Rate (cfs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. 5 Starting Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.86 rncremental Tailwater �epth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.03 Ending Tailwater Depth (ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.46 COMPUTATION RESULTS Flow Tailwater Headwater (ft) Normal critical �epth at outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) Control Control (ft) (ft) (ft) (fps) -------------------------------------------------------------------------------- 0. 5 0.86 0.43 0.69 0.27 0.31 0.83 0.92 0.6 0.89 0.48 0.73 0.29 0.34 0.83 1.11 0.7 0.92 0.52 0.78 0.32 0.37 0.83 1.29 0.8 0.95 0.57 0.83 0.34 0.4 0.83 1.48 0.9 0.98 0.61 0.88 0.37 0.42 0.83 1.66 1.0 1.01 0.65 0.93 0.39 0.44 0.83 1.85 1.1 1.04 0.69 0.98 0.41 0.47 0.83 2.03 1.2 1.07 0.74 1.04 0.43 0.49 0.83 2.22 1.3 1.1 0.78 1.1 0.45 0.51 0.83 2.4 1.4 1.13 0.82 1.16 0.48 0.53 0.83 2. 59 1.5 1.16 0.86 1.23 0. 5 0.55 0.83 2.77 1.6 1.19 0.91 1.3 0. 52 0.57 0.83 2.96 1.7 1.22 0.95 1.37 0. 54 0.59 0.83 3.14 1.8 1.25 1.01 1.44 0.56 0.6 0.83 3.33 1.9 1.28 1.06 1.51 0.59 0.62 0.83 3. 51 2.0 1.31 1.1 1.59 0.61 0.63 0.83 3.7 2.1 1.34 1.15 1.67 0.64 0.65 0.83 3.88 2.2 1.37 1.21 1.75 0.67 0.66 0.83 4.07 2.3 1.4 1.27 1.83 0.7 0.68 0.83 4.25 2.4 1.43 1.34 1.92 0.76 0.69 0.83 4.44 2.5 1.46 1.4 2.01 0.83 0.7 0.83 4.62 -------------------------------------------------------------------------------- HYDROCALC Hydraulics for windows, version 1.2 Copyright (c) 1996 �odson & Associates, Inc. , 5629 FM 1960 west, Suite 314, Houston, Tx 77069 Phone: (281)440-3787, Fax: (281)440-4742, Email :software@dodson-hydro.com Page 1 The Landing—Technical Information Report 6 SPECIAL REPORTS AND STUDIES A geotechnical report completed by Geotechnical Consultants Inc. has been submitted separately. December 19,2007 � 6-1 Job#05-071 T�D � ♦SS�CIaiEs _ The Landing—Technical Information Report 7 OTHER PERMITS Not applicable, all required permits will be a part of a separate submittal. December 19,2007 � 7-1 Job#05-071 T�� , . SSOCIAtES _ The Landing —Technical Information Report 8 TESC ANALYSIS AND DESIGN Phase 1 A temporary erosion and sedimentation control (TESC j plan �vas submitted on Au�ust 16, 2006 as part of the Rough Grading Plan. The erosion control measures consists of 6' high fencing around the entire site (Ph 1 and Ph 2), two temporary construction entrances, and a stockpile/staging area sunounded by silt fencing. Phase 1 will be excavated with a 1% slope towards Park Ave N. A sump and gravel filter will be located on the northwest corner of Phase 1, collecting construction runoff and pumping it to a temporary sediment pond (162'x82'x7') on the north side of N lOth Drive. Treated storm water will be discharged east to Garden Ave N and flow north in the existing 54" storm drain system. The sediment pond sizing calculations are included at the end of this section. If the sediment pond does not meet the w�ater quality standards set forth by the NPDES permit, a Baker Tank may be required to provide adequate treatment. Phase 2 A temporary erosion and sedimentation control (TESC) plan ��-ill be submitted as part of the , Phase 2 Construction Permit Application. It is anticipated that a settling trap will be used on the west side of the site and pumped to a Baker Tank located just south of Logan Avenue and discharge to CB 16. December 19,2007 � 8-1 Job#05-071 1'�AD �'�� - The Landing—Technical Information Report Appendix 8 Sediment Pond Sizing December 19,2007 � 8-2 Job#05-071 T=,�� The Landing—Technical Information Report 9 BOND QUANTITIES, FACILITY SUMMARY AND DECLARATION OF COVENANT 9.1 Bond Quantities The Bond Quantity has been included in Appendix 9. 9.2 Facility Summaries The Facility Summary Sheet has been included in Appendix 9. 9.3 Declaration of Covenant Not applicable. December 19,2007 � 9-� Job#05-071 'I`i�lt-�D �S+SOCIaTES / _ _ The Landing —Technical Information Report Appendix 9 Bond Quantiry Faciliry Summary Sheet December 19,2007 � 9-2 Job#05-071 Ti�l�-�D . SSOCIATES _ � Site Improvement Bond Quantity Worksheet O King County Department of Development 8�Environmental Services 900 Oakesdale Avenue Southwest Renton,Washington 98055-1219 For alternate formats, call 206-296-6600. 206-296-6600 TTY 206-296-7217 Pro)ect Name: The Landing (Ph 1 and Ph2) Date: 1/15/2007 �ocat;on: Renton, WA Project No.: 06-213 (Triad Proj Number) Activity No.. Note: All prices include labor, equipment, materials, ovefiead and Clearing greater than or equal to 5,000 boa�d feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. yes X no j If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 Unit pnces up : 02/12/02 V� �4/22/02 �r� n,...a n......a:a...,�.. t`Isn�4 ni�thn AACC Wnlr-�•YFn s� �• ••inntin4�nnv/r1�Ioe RPn�rt nat�---.��i�nm Site Improvement Bond Quantity Worksheet . � � ,. . Unit ; k � ' #of . . . . .. Y ...�. ,. . . .. � �•'' . ,, , .. ; . `? 4'-. .';�-.. 'f ....: ; _ . . � f=.a:��Refe'rence�l°` � .;. ,p�ice�R�;.i Unrt :'; ....Quant� �`� •'�-.Appi�cations . Gost •:: EROSIO.N/SEDIMENT C.ONTROL„�;'..� ,,�;.: Numtier� ,,;"�' ;• -` `: ." ��'" ` �' ' ` "'`^ ' ,, -.�... :�,:s�= �; �=��'.�,.. ��:: �; E3ackfll 8 compaction-embankment ESG1 $ 5.62 CY Check dams, 4" minus rock ESG2 SWDM 5.4.6.3 $ 67.51 Each Crushed surfacing 1 1!4" minus ESC-3 WSDOT 9-03.9(3) $ 85.45 CY Ditching ESC-4 $ 8.08 CY Excavation-bulk ESC-5 $ 1.50 CY 9400 1 14100 Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 1360 1 1877 Fence,Temporary(NGPE) ESC-7 $ 1.38 LF Hydroseeding ESC-8 SWDM 5.4.2.4 $ 0.59 SY Jute Mesh ESC-9 SWDM 5.4.2.2 $ 1.45 SY Mulch, by hand, straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.01 SY Mulch, by machine, straw, 2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY 1500 1 795 Piping,temporary, CPP, 6" ESC-12 $ 10.70 LF Piping,temporary, CPP, 8" ESC-13 $ 16.10 LF Piping, temporary, CPP, 12" ESC-14 $ 20.70 LF 407 1 8425 Plastic covering,6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 2.30 SY 4700 1 10810 Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each 2 1 5857 Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each 1 1 1949 Sediment trap, 5' high berm ESC-20 SWOM 5.4.5.1 $ 17.91 LF Sed.trap, 5'high, riprapped spiliway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF 480 1 32899 Seeding, by hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Sodding, 1"deep, level ground ESC-23 SWDM 5.4.2.5 $ 6.03 SY Sodding, 1"deep, sloped ground ESC-24 SWDM 5.4.2.5 $ 7.45 SY TESC Supervisor ESC-25 $ 74]5 HR Water truck dust control ESC-26 SWDM 5.4.7 $ 97.75 HR :, . , . .. , . ,,w , . , .. _ -. _ ::. .. .. ,: _: _ . . �. , ,,, .. Each Construction Fencin $ 3.00 2320 1 6960 ESC SUBTOTAL: $ 83,672.64 30%CONTINGENCY 8 MOBILIZATION: $ 25,101.79 ESC TOTAL: $ 108,774.43 COLUMN: A Page 2 of 9 Unit prices uF : 02J12/02 V 04/22/02 �in n�__�n.._.�a:�....�., !"AwnD n�rl iMe A11GC WoM��I*o s* wuau mo*m/rr nnv/rlrloc Reoort Dat�_ .�15/2007 Site Improvement Bond Quantity Worksheet -; Existlng ;-Future.Public Pfirate • Quantity Completied . - *''�` , Righf-of-Way Road I p vements Improvements (Bond Reduction)• - .d x f<:.;, +3 " � � ,� ' k _ � -, � ,;E�Oralna e,F.acilidea� ` n =='-�3 ;�`,.n,,. Quant . ; .. ,,. ., - , _ ,.. ,: - , : . � . ,- . _. ... ...,.. �._.., c.-. '1.� .:-: �., ' ., " -_ s: .r ..,-�_..ti.. �, �..F . .,.,. :.�::.,�;,..w ,.�„ ,.� ..,�,,. � •t=-i'tt".�Y'- Y .a..., ... �.... .. . ... . . . ...., Backfill 8 Com adion-embankment GI-1 $ 5.62 CY Backfill&Com action-trench GI-2 $ 8.53 CY Clear/Remove Brush,b hand GI-3 $ 0.36 SY C�earin /Grubbi ree Removal GI-4 $ 8,876.16 Acre Excavation-bulk GI-5 $ 1.50 CY Excavation-Trench GI-6 $ 4.06 CY Fencin ,cedar,6'hi h GI-7 $ 18.55 LF Fencin ,chain link,vin coated, 6'h' h GI-8 $ 13.44 LF Fencin ,chain link, ate,vin coated, 2 GI-9 $ 1,271.81 Each Fencin ,s lit rail,3'hi h GI-1 $ 12.12 LF Fill 8 com act-common barrow GI-11 $ 22.57 CY Fill&com act- ravel base GI-t $ 25.48 CY 2800 71,344.00 Fill&com act-sc.�eened to soil GI-1 $ 37.85 CY Gabion, 12"dee ,stone filled mesh GI-1 $ 54.31 SY Gabion,18"dee ,stone filled mesh GI-1 $ �4.85 SY Gabion,36"dee ,stone filled mesh GI-1 $ 132.48 SY Gradi ,fine,b hand GI-1 $ 2.02 SY Gradin ,fine,with rader GI-1 $ 0.95 SY 37900 36,005.00 Monuments,3'lon GI-1 $ 135.13 Each Sensitive Areas Si n GI-2 $ 2.88 Each Soddin ,1"dee ,slo round GI-21 $ 7.46 SY Surve ,line 8 rade GI- S 788.26 D Surve 'n ,lot IocatioMines GI-2 $ 1,556.64 Acre Traffic control crew 2 fla ers GI-2 $ 85.18 HR Trail,4"chi wood GI-2 $ 7.59 SY Trail,4"crushed cinder GI-2 $ 8.33 SY Trail,4"top course GI-2 $ 8.19 SY Wall,retainin ,concrete GI-2 $ 44.16 SF Wall,rockery GI-2 $ 9.49 SF Page 3 of 9 SUBTOTAL ��9•� Unit prices u� ' 02/12/02 4/22/02 ,.., ,�authorizes on�y one bond reduction. ._ _ . _ .. . n�--�-•...�_ nn�c�ui_�_�._..� ........,.«..w..r........./.�.Ie� RPnnrt f1ar� 1/15/7OO7 Site Improvement Bond Quantity Worksheet ,�. ., :ExfsHng Future Public Privaba- gond:Reduction' : . . e Right=of-way �Road Improverr�nffi Improvem�erHs -- - - ...�� -�n � Y'�, :B�Dralna e.Facili'ties: ;}-: ,: 4 - Quanf_ - �, - . ,.. .� , - •�+ � � ROAD�IMPROY�EMENT' . , No . ., ', .,. `',. . ,,_: . .. . _ :" ,r,* ,. ,. • y..:�, ,, ;:. ; , _ . .�., . . .,,,,., , _ .v � .,.. i � :i£� AC Grindin ,4'wide machine< 1000s RI-1 $ 23.00 SY AC Grindin ,4'innde machine 1000-200 RI-2 $ 5.75 SY AC Grindin ,4'wide machine>2000s RI-3 $ 1.38 SY AC Removal/Disposal/Repair RI-4 $ 41.14 SY Barricade, pe I RI-5 $ 30.03 LF Barricade, III(Permanent RI-6 $ 45.05 LF Curb&Gutter,rolled RI-7 $ 13.21 LF 125 1,658.75 Curb 8 Gutter,vertical RI-8 $ 9.69 LF 600 5,814.00 Curb and Gutter,demolition and dis osa RI-9 $ 13.58 LF Curb,extruded as halt RI-10 $ 2.44 �F Curb,extruded concrete RI-11 $ 2.56 lF 105 268.80 Sawcut,as hait,3"depth RI-12 $ 1.85 LF Sawcut,concrete,per 1"de th RI-13 $ 1.69 LF Sealant,as halt RI-14 a 0.99 LF Shoulder,AC, (see AC road unit rice) RI-15 5 - SY Shoulder, ravel,4"thick RI-16 $ 7.53 SY Sidewalk,4"thick RI-17 $ 30.52 SY 550 16,786.00 Sidewalk,4"thick,demolition and dis os RI-18 $ 27.73 SY Sidewalk,5"thick RI-19 $ 34.94 SY Sidewalk,5"thick,demolition and dis o RI-20 $ 34.65 SY Si n,handica RI-21 $ 85.28 Each Stri in , r stall RI-22 $ 5.82 Each Stri in ,thermo lastic, for crosswalk RI-23 $ 2.38 SF Striping,4"reflectorized line RI-2 $ 0.25 LF Page 4 of 9 SUBTOTAL 24,527.55 Unit prices u� 02/12/02 �authorues only one bond reducGon. _„ 4/22/02 �,,..,__�,...__.�. ._�_ �...--a-•...�_nn��ui_�-��-. ..�.�.'��I�4��../JJ�� DnnA Il�ti �ii�i�nm Site Improvement Bond Quantity Worksheet - Existing, Future Public - � Private ;.>Bond Reduction• ' � Right-of-way,: ' Roadlmprovomenta ;`�Ylmprovements .�; " "'�'�-.�' '� . : „ . � � .:;. . �.. - :;� , ., ,_ , ,... _ .. _.v .,:: :_. � ,._ .; - . _ .:� �.eS�,:'i�. <:.. �Quant,� '" # -��b'Dralna e'FacilFtlas-. � - �+�::✓"~ - "swt� ,�.:_ t. . ., ..,� _ RQA[3�SU:R�ACIN ._ . ,,;T ... ., . . .,, .. ; ,, .,._ - •, - -._� ,. ,;�. , _ ..... , ,, ,. .. For KCRS'93,(additional 2.5"base)add RS-1 $ 3.60 SY AC Overia , 1.5"AC RS-2 $ 7.39 SY AC Overia ,2"AC RS-3 $ 8.75 SY AC Road,2",4"rock,First 2500 SY RS-4 $ 17.24 SY AC Road,2",4"rock,Q .over 2500SY RS-5 S 13.36 SY AC Road,3",4"rock,First 2500 SY RS-6 $ 19.69 SY 2500 49,225.00 AC Road,3",4"rock,Q .over 2500 SY RS-7 $ 15.81 SY 50 790.50 AC Road,5",First 2500 SY RS-8 $ 14.57 SY AC Road,5",Q .Over 2500 SY RS-9 $ 13.94 SY AC Road,6",First 2500 SY S-1 $ 16.76 SY AC Road,6",Q .Over 2500 SY S-1 $ 16.12 SY As halt Treated Base,4"thick S-1 $ 9.21 SY Gravel Road,4"rock,First 2500 SY S-1 $ 11.41 SY 2500 28,525.00 Gravel Road,4"rock,Q .over 2500 SY S-1 $ 7.53 SY 50 376.50 PCC Road,5",no base,over 2500 SY S-1 3 21.51 SY PCC Road, 6",no base,over 2500 SY S-1 S 21.87 SY Thickened Edge S-1 $ 6.89 LF Page 5 of 9 SUBTOTAL 78,917.00 Unit pnces u �� 02/12/02 A authorizes only one bond reduction. 4/22/02 �... .,.. ...._ ... .. n�.__a�...�� nncc��u��-�u....� ..............�...L......../.d.J.... Annnrt flo._ �/1�f7M7 Site Improvement Bond Quantity Worksheet , ' Exist3ng ; Future;Public., •Private BonA`Reduction' A� Right=of way>: �4 Road Improvements: Improvements , .�.:_ . _ , . _ , . , , ,�. . ,. : _ , .. ,;' . Y.,,y� � . . i� � ,�8 Faclltdea "' .�.'- � Quant, .. ,, _ . .-. ' -'+: .. ,..z r)1 . :,, � .�.�r "` relne e. D �� '�,r' .�„a'. '' t , . ,; , :.,,... �v-- .. . - - DR�A1�4C .. .. . .. .. .. . _, - - - Access Road,R/D D-1 $ 16.74 SY Bollards-fixed D-2 $ 240.74 Each Bollards-removable D-3 $ 452.34 Each '(CBs inGude frame a�d lid) CB Type I D-4 $ 1,257.64 Each 7 8,803.48 CB T pe IL D-5 $ 1,433.59 Each CB T pe II,48"diameter D-6 $ 2,033.57 Each 8 16,268.56 for additional depth over 4' D-7 $ 436.52 FT 22 9,603.44 CB T e II,54"diameter D-8 $ 2,192.54 Each for additional depth over 4' D-9 $ 486.53 FT , CB T pe II,60"diameter D-10 $ 2,351.52 Each for additional depth over 4' D-11 $ 536.54 FT CB T pe II,72"diameter D-12 $ 3,212.64 Each for additional depth over 4' D-13 $ 69221 FT Throu h-curb Inlet Framework Add) D-14 $ 366.09 Each 2 �32��8 Cleanout,PVC,4" D-15 $ 130.55 Each Cleanout,PVC,6" 0-16 $ 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" 0-20 $ 13.33 LF Culvert,PVC, 12" D-21 $ 21.77 LF Culvert,CMP,8" D-22 $ 17.25 �F CutveR,CMP, 12" D-23 $ 26.45 LF Culvert,CMP, 15" D-24 $ 32.73 l.F 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 of 9 SUBTOTAL 35,407.66 Unit prices u �� 02/12/02 _ A authorizes only one bond reduction. 4/22/02 �,,..,__�,,..--•�---'- rti....�....��..,nnce w N��fsa s� ....._...+.et..,1�.-....v/rlrlec RPnnrt fla,.. 1/�5/2007 Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction' Right-of-way Road Improvements Improvemer� - DRAINAGECONTINUED : . :. ;; . -.,� �.; ..•bDrainage.Facilities ..: ��` -f Quanti ;,.r . ��p .. -.. ,. .. .-q '.. 3:. '... _ � - - �~, tr:G�4: „(.•... �� ..� r k' „3� `�1 Culvert,Concrete,8" D-32 $ 21.02 LF Culvert,Concrete, 12" D-33 $ 30.05 LF Culvert,Concrete, 15" D-34 $ 37.34 LF Culvert,Concrete, 18" D-35 $ 44.51 LF Culvert,Concrete,24" D-36 $ 61.07 LF Culvert,Concrete,30" D-37 $ 104.18 LF Culvert,Concrete,36" D-38 $ 137.63 LF Culvert,Concrete,42" D-39 $ 158.42 LF Culvert,Concrete,48" D-40 $ 175.94 LF Culvert,CPP,6" D-41 $ 10.70 LF 22 235.4 Culvert,CPP,8" D-42 $ 16.10 LF �� 2�3.� Culvert,CPP, 12" D-43 $ 20.70 LF 379 7845.3 Culvert,CPP, 15" D-44 $ 23.00 LF Culvert.CPP. 18" D-45 $ 27.60 LF Culvert,CPP,24" D-46 3 36.80 LF Culvert,CPP,30" D-47 $ 48.30 LF Culvert,CPP,36" D-48 $ 55.20 LF Ditchin D-49 $ 8.08 CY Flow Dis ersal Trench 1,436 base+ D-50 $ 25.99 lF French Drain 3'de th D-51 $ 22.60 LF Geotextile,laid in trench, o ro ne D-52 $ 2.40 SY Infiltration pond testin D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'dee D-54 $ 1,605.40 Each Pond Overflow S i1Mra D-55 $ 14.01 SY Restndor/Oil Se arator, 12" D-56 $ 1,045.19 Each Restrictor/Oil Se aretor, 15" D-57 $ 1,095.56 Each Restrictor/Oil Separator,18" D-58 $ 1,146.16 Each Ri rap, laced D-59 $ 39.08 CY Tank End Reducer 36"diameter D-60 S 1,000.50 Each 7rash Rack, 12" D-61 $ 211.97 Each Trash Rack, 15" D-62 $ 237.27 Eactt Trash Rack,18" D-63 S 268-89 Each Trash Rack,21" D-64 $ 306.84 Each Page 7 of 9 SUBTOTAL 83�4 Unit prices u� '� 02/12/02 ,. ,�authorizes only one bond reduction. ... 4/22/02 .... _ . ., ... . i...--�' -..�.�._ �n�n ui�►��i.� �. ..�.�..�....�..�...��.,a�.�.... GnnnA fln.. 1/��,/')(1(17 Site Improvement Bond Quantity Worksheet � Exiating :,ir Future Public Private Bond^Reduction• �- Right-of-way � Road,lmprovements � Improvemer�ts .,� -,� .,�r.::� � :' wz�, .�:.^^�,fi� �,b Dralna e PacilftJes � ��,c�K; ' .��: �"Y Quaqt. ,,,�^ , , - - - t.��..;�. _ F.;. . .... . . .. .� ..... ....y_ . . ,� - ��'. No. 2"AC,2"to course rock 8 4"borrow PL-1 $ 15.84 SY 2"AC, 1.5" to course 8 2.5"base cou PL-2 $ 17.24 SY 4"select borrow PL-3 $ 4.55 SY 1.5"top course rock 8 2.5"base course P�-4 $ 11.41 SY (Such as detention/water ual' vaufts. No. 3 Cartrid e Catchbasin StortnFilter WI-1 a13,250.00 Each 2 26,500.00 WI-2 SY WI-3 CY 12"dia Ductile Iron Pi WI-4 3 42.00 LF 190 7.980.00 WI-5 FT WI-6 WI-7 WI-8 WI-9 vh-to SUBTOTAL 34,480.00 SUBTOTAL(SUM ALL PAGES): 289,035.61 30%CONTINGENCY 8 MOBILIZATION: 86,710.68 GRANDTOTAL: 375,746.29 COLUMN: B C D E Page 8 of 9 Unit pnces uE 02/12/02 .._ �authorizes only one bond reduction. 4/22/02 -- - ... .. . n�.__� _....�_ nn�c�ui_�._ts�..� ..............w..�........./.I.Is� ao..�,�►na,. ,i��i�nm Site Improvement Bond Quantity Worksheet Original bond computations prepared by: Name: The Landing (Ph 1 and Ph2) �ate: 1/15/2007 PE Registration Number: 41846 Te1.#: 425-821-8448 F�rm Name: Triad Associates Address: 12112 115th Ave NE Kiricland,WA 98034 Pr,ojea No: 06-213(Triad Proj Number) ROAD IMPROVEMENTS 8 DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBLIC ROAD 8 DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND' REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control(ESC) (A) $ 108,774.4 TEMPORARY OCCUPANCY"' Existing Right-of-Way Improvements (B) $ - Future Public Road Improvements&Drainage Facilfies (C) $ - Private Improvements (D) $ 375,746.3 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond'J" (A+B) $ 108,774.4 (First$7,500 of bond'shall be cash.) Performance Bond*Amount (A+B+C+D) = TOTAL (T) $ 484,520.7 T x 0.30 $ 145,3562 OR mimum n amount is . Reduced PerfoRnance Bond'Total"' (T-E) $ 484,520.7 Use larger o x or - (B+C)X Maintenance/Defect Bond'Total 0.25= $ - NAME OF PERSON PREPARING BONO'REDUCTION: Sh@fl MUfetB Date: 1/1 S/2007 '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►estorallon bonds to be combined when both are required. The restoration requirement shall indude the total cost for all TESC as a minimum,not a maximum. In addition,corrective worlc,both on-and off-site needs to be inGuded. Quantities shall reflect worse case scenarios not just minimum requirements. For example,ff a salmonid sVeam 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 remeining after reduetio�shall not be less than 30°�of the original amount(T)or as revised by major design changes. SURETY BOND RIDER NOTE: (f a bond rider is used,minimum additional performance bond shell be $ 375,746.3 (C+D)-E REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES ..�f 9 Unit prices upd� 02/12/02 Check out the DDES � �at www.metrokc.aov/ddes Ve 4/22/02 �,- �__a n..__.:...._�_ Rnnnr4 llatc ,��i�nm }�I�JG COU:�1T1', �1'ASHINGTON, $URFACE 1'�'A"CfiR DESIGV :�IAhU,aL STORl��1WATER FACILITY SUNiMARY SHEET Development: The Landin� Date: Februarv 2, 2007 Location: Renton, WA(area bounded bv Logan Ave N, Park Ave N, N 10`h St Garden Ave � ENGINEER: Triad Associates DEVELOPER Name: Mark Reeves, P.E. Name: Mazk Faulkner Firm: Triad Associates Firm: Fai�eld Residential Address: 12112 115th Avenue NE Address: 1109 I S' Ave , Suite 402 Kirkland, WA 98034 Seattle, WA 98101 Phone: 425 821-8448 Phone: 206 624-4464 Developed Site: 6.7 Acres Number of lots: N/A Number of detention facilities on site: Number of infiltration facilities on site: 0 ponds 0 ponds 0 vaults 0 vaults 0 tanks 0 tanks Flow control provided in regional facility(give location) n/a No flow control required n/a Exemption number Downstream Draina e Basins Immediate Ma'or Basin Johns Creek Cedar River Number&type of water quality facilities on site: 0 biofiltration swale (regular/wet/or 0 sand filter (basic or large?) continuous inflow?) 0 sand filter, linear(basic or large?) 0 combined detention/WQ pond 0 sand filter vault (basic or large?) (WQ portion asi or lazge?) 0 combined detention/wetvault 0 stormwater wetland 0 compost filter 0 wetpond (basic or large?) 0 filter strip 0 wetvault 0 flow dispersion 2 Catchbasin StormFilter 0 farm management plan 0 landscape management plan 0 oil/water separator (baffle or coalescing plate?) 0 catch basin inserts: Manufacturer 0 pre-settling pond 1998 Surface Water Design Manual 9/l/98 1 KING COUNTY, Vb'.ASHINGTON, SLRFACE «'ATER DESIGN h1ANUAL , 0 pre-settling structure: Manufacturer_ 0 flow-splitter catchbasin DESIGN INFORMATION 1NDIVIDUAL BASIN Wetpool Water Quality Design Volume(Vb) N/A I Water Quality treated volume or wetpond(Vr) N/A DESIGN TOTAL INDNIDUAL BASIN INFORMATION, cont'd Drainage basin(s) To Garden To Pazk C D Onsite area 0.32 ac 0.34 ac Offsite area N/A N/A Type of Storage N/A N/A Facili Live Stora e Volume N/A N/A Predeveloped Runoff 2-year 3.42 cfs Rate 10- ear 5.14 cfs ' 100- eaz 7.03 cfs �evelo d runoff rate 2- ear 0.76 0.79 10- ear 1.17 1.21 100- ear 1.59 1.64 T e of restrictor N/A N/A Size of No. 1 N/A N/A orifice/restriction No. 2 No. 3 No. 4 FLOW CONTROL& WATER QUALITY FACILITY SUMMARY SHEET SKETCH All detention, infiltration and water quality facilities must include a sketch per the following criteri a: 1. Heading for the drawings should be located at the top of the sketch(top right-hand corner). The heading should contain: • North arrow (point up or to left) • D9# • Plat name or short plat number � Address (nearest} � Date drawn(or updated) • Thomas Brothers page, grid number � Label CBs and MHs with the plan and profile designation. Label the control structure in writing or abbreviate with C.S. Indicate which structures provide spill control. 3. Pipes-- indicate: 911/98 1998 Surface W'ater Design Manual 2 The Landing —Technical Information Report 10 OPERATIONS AND MAINTENANCE The applicable portions of the operating and maintenance manual from the 1990 King County Surface Water Manual and the operating and maintenance manual from Contech Stormtivater Solutions has been included in Appendix 10. � December 19,2007 � 10-1 Job#05-071 TR�D ,s�:��,r-_, ! The Landing —Technical Information Report Appendix 90 Portion of Appendix A -1l�laintenance Requirements for Privately;ifuintained Facilities (1990 KCSWM) Stor�mFilter• Operations and.tiiaintenance .�tifanual December 19.2007 \ 10-2 Job#05-071 Ti�T A i> 1 i\lt'�L ♦SSOCIaTES /_ K1NG COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL I ) NO. 5 - CATCH BASINS I M,Inbn,no� conaMlo�s vMh.e Maln�nano. Raula Exp.ol�d Compor�n D�Not N NNd�d VYh�n Mainb+uino�Is P�►fornNd (3enera! Tra�h�Deb�is Tnth a Mbri�of mon tt►an 1/2 cublo No traah or debrit locabd Immedtatsly In (�1ud�s foot wNoh Is{ooat�d imm�dla�y ln �hoM hont o1 catch basln op�r►Inp. S�dlm�nt) of tlN atoh bain op�ninp or is bloolc n� o.proity a e�Nn ay mon th.n �ox. , T�ath or dNxls Qn tM bak►�tlut No Vatf►a d�is In 1M oatch baeln. ' �xoMd�1/S 1M d�plh trom 1M botEom ' a bain a irrwrc a tn.�ow�st pip.Uto ' «out ol th.b�Mn. , Ta�h«tl.aa In.ny rd.t cr ouq.t plrk Inbe and oua.c ptpes frs.ol aael,or blookkp nwr�1Mn 1/3 of its Mipht dsbrit. Daid aetlmNs or wp�ldion lhat oould No d�ad ar�ktuds or wqetatlon Pns�nt p�e�aN odorf thtt wo��ld o�uN v�tthk�1M calch batln. oompaM�b or d�+0�row pw�(�•p•, �� o.poWb a�arbao..xw�inp t cubio No oondiuon pnanc wl,�a�vroutd sterace toot In volurt►�. ot wpport tM brMdin�ot Inascb or rod«►ts. Shuctural Damage CanM of 1rart��xt�nda mon tlan 3/4 Frams Is evsn wNh aub. 10 Fram��nd/a Mch pat cutb ho�iMo.1M s1rMt Qf Top S�ab appuwbNl• Top dab Ms hoNs IarpK than 2 rquan Top siab is frea of hoks and cxacks. {ncMs a aada wW�r than 1/4 k�oh , pnbnt is b mak�sun all maE�rlal b ' rurwfin�in�o UN Dilln). Fnrtw not sktlnp ttwh on Eop tlab,i.�.. Fram�b sitUnp flush on top slab. ap�ratlon ot mor�Mwi 3/4 kx:h d th� trvr�1rom ttw top Nab. Cracics in 8asin A'acb wklM tt►an 1/2 Moh and laip�r BaNn roptawd or npairod to dalpn w.u./eonom b,.n 9+..t.�r+�►w+d�no.a.o+�pwna.. .tand.rds. .nN��rp o�oh baan thrarp++«aoks.or mdnM��p�r�on�udp�s riat struatun Is umax�d. Crecla wW�r then 1 2 ktch and IorpK No aacks mon th�n 1/4 Inch vvid�at th� u�.n 1�ooe ae n,.p�in a.ny in�.t/o�a.c bMt of InNe/a,uet pips. pip�u u►y ww«�o.a.op paroa.. �rrt�rkp oatoh ba�ln thraph oaoki. S�tthmsnt/ Ba�ln has�ettNd mon than 1 inch or has Basin nplaced a repaind M deaipn Misall�nment rotabd mon tl►an 21nch�s out of st�ndarda. alipnm�nt. Fln Hezard Pree�na o1 chemloal�wch as�aturel No ilammabls ch�mloale prsaent. flaa�dl�u�d pa�olir�. Vspetatio� Wp�pidon prowln��s end blodcln� No wpetaMon blocklnp op�ninp to baeln. mon than 10'!�of iM basln op�►Inp. VpNatbn�rowinp in inl�t/oud�t pip� No vepetetlon or root prwvth pressnt joiMa that�e mon than tlx IncM�WI and lett thut�Ix IncMa apart. PoIIuNon NoMlammable chtmloala o1 mon than No pollutlon present other than suAace 1/2 cub{c}001 per thrse teet oi basin tilm. length. J -" - NG COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL �. 5 • CATCH BASINS (Contlnued) � � Mal�no� CadNlon�Wh�n M�MrMnano� R�wles Exp�oMd Canpon�et D�Not 1� NNd�d Wh�n M�N�ano�la P�MrnMel Gedt eaaln Cowr Cowr Not In Plaa Cawr b mlak�p or onN Wrt►aIN in plao�. Gtoh basln oowr i�dos�d. My op�n a�oh b.�in nqukss m�inbnar►o�. Lookinp �A�oFunlNn Cannot b�op�rnd by oM M�ohaniWn op��wNh propK tools. �A�ohanlwn Not m�►Mnano�p�non wNh prop�r foola. Wbrkk�p Bolb inb ham�h�w Na Muu�t/Z inch of Mwwd. (�ov�r DiMioult to On�mak�nano�p�ton orwtot nrt�ow C�o+rK can b�nmowd by or►� FMnww Nd NMr applyMp 80 ba.of I�kM�M Is malr►bnana p�non. la�p oowr irom�Mp o1f�oo�t� malnMn�na. Ladd�� laddN RunQa LaddK It Wlah dw brt�funQs. Ladd�r mNb dNlpn at�ndaN��nd llnsah rMtMpr�r►�nt,nat.or�olcs, �ha rp allows mak�l�ano�pK�on sd�aoo�a. � IrNtal Cirabs (3raM wMh op�ninp wldw than 7/8 kx:h. Cxat�op�ninflt mNt detl�n �tandards. (H�PP�I Ttash and D�bris Trdh and d�b�is that b bbdckp mor� Grab hN.of traah and dsbris. u,.n 2ox a pral.axtao.. D�msped or (3nb mfsalnp u brok�n rr►�mber(s)ot Grats b in plaw and mests dsalpn Mseinp tM pat�. atendarda. C � � A-6 1/�) KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL - NO. 10 - CONVEYANCE SYSTEMS (Pipes & DltChes) l � MalnMnano� Con�11oM WhM QAalnttnano� R�sult�Exp�cbd c,ompa+.M a�.ot a N«a.a wn«,M.Inan.no.�. w�orm.a p{p�s S�dim�M d�O�br{s AooumuUbd wdim�nt that�xo�edt 209i Plp�cNan�d ol dl s�dlm�M�r►d debris. of tM dlarn�b►o(tM pip�. WpNNlon �tlon that nduoa 1n�mov�ment of /lll vp�atlo�nmowd w wata Aows watsr tlNouph PIPa. fnNY lhrou0h P�P�a• D�map�d ProMotlw oodk►p b cl�map�dt rust It Plp�npaind or nplao�d. owNrp rrlon fhan 60%dtbr{ontlon eo .�►v«e a v+p.• Any d�nt 11►�It..d�awa 1M oroa acuon Plp�np�k�d a nptao�d. wR of plp�Cyy moa�Man 20li. Op�n DttcMs T►afh�D�brl� Tfa�h e1d d�bris�xoNda 1 oublo foot Tra�h and d�bris oNand irom dfb11». p�r��000 wuw�..c a a�ea,.�d aop... 3�dlrtwnt /Ioowrx�Md»dMrnrM tlut�xoNdt 20% Dilch cNarNd/11usMd of aN»dtrr�nt and d tl»daipn d�p�lh. d�bris w that k maLoMs d�tlpn. Vp�tatfon Wp�fatlor►lhat nd��fiw mowrr►�M of YVat�r Aows fnNy th�ouph ditcMs. vr�br tlx�ouph diloMt. Erwlon Damap�Lo SN'Ponds'SLndard No. t SM'Ponds'Shu�dud No. 1 �Ws Rook Unfn�Out of Mvnt�nanw p�non can ses natiw soil Rsplaw roeks to d�sifln standard. Pfao�or Missinp (N b�rnath tM rodc Ik►fnp- ��l � Catch Basins SN'Caeoh Basf�s'Sfandard No.S Ss�'Gtch 8asir►s'Standard No.6 D�bris Barrbts SN'O�brff Barri�rs'Star�dard No.6 SN'Debris BarrlKa'Standud No.6 (�.fl..Trash F�ck) J A-11 1� KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL _. 11 - aROUNDS (Landscaping) Mainbnano� Condltlona Wh�n A/alnl�nano� R�autb Exp�al�d � Cpmpon�nt O�Not Is Nwd�d �MI�M� IAaln�nan�1� PKform�d (3�n�n1 1NMds VW�dt prowinp M mor�than ZO%of ths W�ede pnter�t in Nse than 5%of ths (NonPofaono��) tand�oap�d a�na(trsa and thrub�only). land�oaped arsa. 8abty Haz�rd My pr�wnw ot pobon Ny or otl�r No poleonout wpetatton pnsant In a po{wnous wp�Non. land�aap�d usa. Tn�h or Litbr P�P�►,au►�bottly,lqalNn�mon fhan t Arsa clsar ot Iltar. � aibio toot within a i�nd�pap�d ana(vses and thrubt only�of 1,OOQ squar�iMt. Tnes.nd sh�ubs ama0. umDs ot p#ra a v.�.or.Iu�t awt ar. Tr«s and thn,b�w�u,aa uun sx or a,e 2a�7i d 1M�1oW Wqap�of�� eotd foliap�whh�plk a broken Iimt». - thrub. Tn�a or MrvOs th�t haw b�►blown Trs�a eF►nib in ptaa hs�of InJury. down or knodnd ov�r. • Tn�s or Mxubs whfd►w not ad�qu�bly Tn�a shrob In pisa and adequaisly wppori�d or an N�ninp over�caudnp wpport�d;remow any dead a dtssased ucpown d tM roott. Vess. � � A-12 l� Stormwater36� Operation and Maintenance AOWIEQ7 Cs�ary Catc h Bas i n Storm F i IterTM either by sheet flow from a paved surface or from an inlet pipe discharging directly to the unit vault. The inlet chamber is equipped lmportant: These guldellnes should be used with an internal baffle, which traps debris as a part of your sTte stormwater and floating oil and grease, and an overflow management plan. weir. While in the inlet chamber, heavier solids are allowed to settle into the deep sump, while lighter solids and soluble Overview pollutants are directed under the baffle and The CatchBasin StormFilterT"" (CBSF) into the cartridge chamber through a port consists of a multi-chamber steel, concrete, between the baffle and the overflow weir. or plastic catch basin unit that can contain Once in the cartridge chamber, polluted up to f�ur StormFifter cartridges. The steel water ponds and percolates horizontally CBSF is offered both as a standard and as through the media in the filter cartridges. a deep unit. Treated water collects in the cartridge's center tube from where it is directed by an The CBSF is installed flush with the finished under-drain manifold to the outlet pipe on grade and is applicable for both constrained the downstream side of the overtlow weir lot and retrofit applications. It can also be and discharged. fitted with an inlet pipe for roof leaders or similar applications. When flows into the CBSF exceed the water quality design value, excess water spills The CBSF unit treats peak water quality over the overflow weir, bypassing the design flows up to 0.13 cfs, coupled with an cartridge bay, and discharges to the outlet intemal weir overflow capacity of 1.0 cfs for pipe. the standard unit, and 1.8 cfs for the deep steel and concrete units. Plastic units have Applications an internal weir overflow capacity of 0.5 cfs. The CBSF is particularly useful where small flows are being treated or for sites that are Design Operation flat and have little available hydraulic head The CBSF is installed as the primary to spare. The unit is ideal for applications in receiver of runoff, similar to a standard, which standard catch basins are to be used. grated catch basin. The steel and concrete Both water quality and catchment issues CBSF units have an H-20 rated, t�a�c- can be resolved with the use of the CBSF. bearing lid that allows the filter to be Retro-Fit installed in parking lots, and for all practical purposes, takes up no land area. Plastic The retrofit market has many possible units can be used in landscaped areas and applications for the CBSF. The CBSF for other non-t�afflc-bearing applications. can be installed by replacing an existing catch basin without having to "chase the The CBSF consists of a sumped inlet grade,"thus reducing the high cost of re- chamber and a cartridge chamber(s). piping the sto�m system. Runoff enters the sumped inlet chamber www.stormwater360.com Toll-free:800.548.46fi7 1 of 2 02005 Stortnwater360 CatchBasin SlormFilter Operetlon end Maintenance Guldelines Maintenance Guidelines Materials required include a lifting cap, Maintenance procedures for typical catch vactor truck, and fresh filter cartridges. basins can be applied to the CatchBasin Contact Stormwater360 for specifications i StormFilter (CBSF). The filter cartridges and availability of the lifting cap. The vactor contained in the CBSF are easily removed truck must be equipped with a hose capable and replaced during maintenance activities of reaching areas of restricted clearance. according to the following guidelines. The owner may refresh spent cartridges. Refreshed cartridges are also available from 1. Establish a safe woricing area as per Stormwater360 on an exchange basis. typical catch basin service activity. Contact the maintenance department at Stormwater360 (503) 240-3393 for more 2. Remove steel grate and diamond plate information. cover(weight� 100 Ibs. each). Maintenance is estimated at 26 minutes of 3. Tum cartridge(s) counter-clockwise to site time. For units with more than one disconnect from pipe manifold. cartridge, add approximately 5 minutes for each additional cartridge. Add travel time 4. Remove 4" center cap from cartridge as required. and replace with lifting cap. 5. Remove cartridge(s)from catch basin by hand or with vactor truck boom. 6. Remove accumulated sediment via vactor truck (min. clearance 13"x 24"). 7. Remove accumulated sediment from cartridge bay. (min. clea�ance 925" x 11") 8. Rinse interior of both bays and vactor remaining water and sediment. 9. Install fresh cartridge(s)threading clockwise to pipe manifold. 10. Replace cover and grate. 11. Return original cartridges to Stormwater360 for cleaning and media disposal. Media may be removed from the filter cartridges using the vactor truck before the cartridges are removed from the catch basin structure. Empty cartridges can be easily removed from the catch basin structure by hand. Empty cartridges should be reassembled and returned to Stormwater360, as appropriate. www.stormwater360.com Toll-free:800.548.4667 2 of 2 02005 Sbomiweter360 CatchBesin StormFilter Operedon end Mei�tenance Guidelines