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03565 - Technical Information Report - Drainage
41 m STORM DRAINAGE REPORT (Including Downstream Analysis) Talbot Road Townhomes Location: 4701 Talbot Road South Renton,WA 98055 a.k.a. ICC. PARCEL 312305-9090 June 3, 2011 By Hagenson Consultants, LLC Seattle, Washington 98136 HC Job No. 201013 CITY OF RENTON Renton File No. LUA08-017 RECEIVED • OCT 1 0 2011 cF Q (g' "'Asti/4/ PLAN REVIEW -73O 21823 F �FCISTEc SS/ONAL iv1�� CITY OF RENTON RECEIVED OCT 0 7 2011 BUILDING DIVISION 3545 TABLE OF CONTENTS A. Core and Special Requirements Analysis p9.7 B. Technical Information Report I. Project Overview Py if II. Preliminary Conditions Summary PA 11 III. Off-site Analysis(Appendix) IV. Proposed Drainage Improvements Pg 2s V. Conveyance Systems Analysis and Design VI. Basin and Community Planning Areas py `° VII. Other Permits Py ` VITT. Erosion/Sedimentation Control Design P� �D IX. Bond Quantities Work Sheet, Retention/Detention Facility, P5 3 Summary Sheet and Sketch, and Declaration of Covenant,Declaration of Covenant Prohibiting Leachable Metals X. Maintenance and Operation Manual Appendix -Porous Pavement Design and Miscellaneous -Geotechnical Study -Drainage Adjustment Application Letter -Emails supporting detention tank design TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PART I PROJECT OWNER AND PART 2 PROJECT LOCATION PROJECT ENGINEER AND DESCRIPTION Project Owner:Orion Investments,LLC ProjectName:Townhomes Address P.O.BOX 5757 Location:4701 Talbot Road South Bellevue,WA 98006 Renton,WA 98055 Project Engineer:Harold Hagenson, PE Township:23N Hagenson Consultants,LLC 6484-48t Ave SW,Seattle,WA 98136 Range:5E Ph 206-938-6168 Section:31 Fax 206-938-7645 Email:H.Hagenson@comcast.net i' \I. A TYPE OF PERMIT APPLI(:ATION PART 4 OTHER REVIEWS AND PERMITS 1- Subdivision DF W Hl'A Shoreline Management E Short Plat I— COE 404 r Rockery cc/Grading 1— DOE Dam Safety 1 Structural Vaults 1- Commercial 1•" FEMA Floodplain 1— Other IV Other ---Multi-family I-" COE Wetlands PART 3 sITF COMMUNITY AND DRAINAGE BASIN Community Renton Drainage Basin Black River PART 6 SITE CHARACTERISTICS i River 1 Floodplain 1- Stream r Wetlands Critical Stream Reach r Seeps/Springs 1— Depressions/Swales A High Groundwater Table 1` Lake 1- Groundwater Recharge 1- Steep Slopes 1— Other PART - SOIJ.ti Soil Type Slopes Erosion Potential Erosive Velocities Alderwood Gravelly Sandy Loam 6- 15% Slight AT Additional Sheets Attached TOWNHOMES-TIR PAGE 3 OF 29 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET P R I S DEVELOPMENT LIMITATIONS REFERENCE I.!MI I ATION/SITE CONSTRAINT =Downstream Analysis RI Additional Sheets attached P \RT ') I:St RI;t)t IREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION Sedimentation Facilities Fro Stabilize Exposed Surface rj Stabilized Construction Entrance J Remove and Restore Temporary ESC Facilities ✓ Perimeter Runoff ControlI✓ Clean and Remove All Silt&Debris • Clearing&Grading Restrictions r Ensure Operation of Permanent Facilities 507 Cover Practices r Flag Limits of SAO and Open Space Preservation Areas 1 Construction Sequence r Other ✓ Other PART 10 SURFACE WA I I R '•,l STEM Grass Lined ChannelTank r Infiltration Pipe System r Depression Method of Analysis: Open Channel r Energy Dissipater KCRTS Level 2 r Wetland r Flow Dispersal r Dry Pond r Waiver r Wet Pond r Stamm r Regional Detention Brief Description of System Operation: The system will include detention tank,zpg stormfilter and CDS pretreatment. The tank outlet will tie to dispersal trench at the northwest corner of the property. Facility Related Site Limitations Reference I Facility I,imitation P kR 11 I S 1 RUCTURAL ANALYSIS P.kR F 12 EASEMENTS/TRACTS I Drainage Easement r Retaining Wall r Access Easement I— Rockery>4'High r Native Growth Protection Easement I— Structural on Steep Slope r Tract ✓ Retaining Wall r 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. 4C� f/1 r r ► /V(11('i Signed/Date TOWNHOMES-TIR PAGE 4 OF 29 KING COUNTY. WASHINGTON. SURFACE WATER DESIGN MANUAL STORMWATER FACILITY SUMMARY SHEET DDES Permit Number I (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Overview: Project Name 741_23/51 20A1) i JWAI D E Date 2-4-!i Downstream Drainage Basins Major Basin Name 2 LA LIZ. RIVER Immediate Basin Name PAUT9EiL cJ1.iEv Flow Control: Flow Control Facility Name/Number I Facility Location UNDER_ P A VIMEL ILEAn -MU k311l) If none, Flow control provided in regional/shared facility (give location) No flow control required Exemption number General Facility Information: Type/Number of detention facilities: Type/Number of infiltration facilities: ponds ponds vaults tanks tanks trenches Control Structure Location sDM1111 - NDflM4 l3F 14Aht.jLa_ fl AD Type of Control Structure 5+''2' M 14 Number of Orifices/Restrictions Size of Orifice/Restriction: No. 1 0.410 IN No. 2 D . No. 3 No. 4 Flow Control Performance Standard LEVEL 1Z- MMLI.1 WiLif71DAI S '/2-2 774W) S� 2005 Surface Water Design Manual 1/1/05 1 KING COUNTY. WASHINGTON. SURFACE WATER DESIGN MANUAL Live Storage Volume 0,1 u , F- Depth p . 2. F' Volume Factor of Safety Number of Acres Served 0, 9 c Number of Lots Dam Safety Regulations(Washington State Department of Ecology) Reservoir Volume above natural grade Depth of Reservoir above natural grade Facility Summary Sheet Sketch All detention, infiltration and water quality facilities must include a detailed sketch. (11"x 17" reduced size plan sheets may be used) 4TrA046-V I/1/05 2005 Surface Water Design Manual 2 KING COUNTY. .WASHINGTON, SURFACE WATER DESIGN MANUAL Water Quality: Type/Number of water quality facilities/BMPs: biofiltration swale sand filter(basic or large) (regular/wet/or continuous inflow) sand filter, linear(basic or large) combined detention/wetpond sand filter vault (basic or large) (wetpond portion basic or large) sand bed depth (inches) combined detention/wetvault stormwater wetland filter strip V; storm filter 7 P& M LDArr t,4 flow dispersion wetpond (basic or large) farm management plan wetvault landscape management plan Is facility Lined? oil/water separator If so, what marker is used above (baffle or coalescing plate) Liner? catch basin inserts: Manufacturer pre-settling pond pre-settling structure: Manufacturer high flow bypass structure (e.g., flow-splitter catch basin) source controls Design Information Water Quality design flow D.1 D5 CF Water Quality treated volume (sandfilter) Water Quality storage volume (wetpool) Facility Summary Sheet Sketch 2005 Surface Water Design Manual 1/1/05 b �0 LID I RIA. ._0.1 - I. RIM = 138.0 OVERFLOW EL = 146.88 RII IE = 135.5 IE OUT = 138.22 COPPER RIDGE APARTMENTS I 1E( KC PARCEL NO. 3123059041 SITE N15'22'w 4.34'y 41,361 ±sq.ft. 0.94 acres N = 162650.65 6' WOOS BOARD FENCE E = 1298948.43 31, T- t 23N, R-5E, W.M. - N6901 00 ' I s "+ , •6.30 o• �. ....., ' - -- — , _ i _ �'C jjj C 58 � ` - & r > Ir"iiii. 7 -IA :111 II Z fri LIJ OF 15% SLOPE o g I DISPERSAL a,. all a 1 PER STD r e PLAN 224 f 1 f s I d U 1 $ A t I CJ — I f , v Y 3 iy 5 �J� :1,....1 l 1d :!:j; PORONC150N /k RIDGE APARTMENTS 11:1 J PCP) f ' . . f i , I DEL NO. 3123059153 in 0o 'co 10 00 11+00 di I . 111 I TA OT LANE.a ,r I a M I 12+00 N 89.58' 00" W 1 oSTA 1 83.33 H.H v II N® I _ S MH 2 �I _ 3w �I1le1:111w. /�� Sav CO z . �..���.;� -12®2,4%(PCP) (PCP) lN - • — I�� p I — _ SIE ' IZ 3 �11'IIi'S�■-'l� W H r a V - - — O _ m I cs 8LF-1. 01.2X ��� .. _ _ z ' II 1z iii ZPG H 60 o Si.,77-. 1 - 1-: c5 -- I- I I N N = 1 9.501 # O Z ,F RI ' 149.36 ,ji i = 1 20 14' ,g 3 F- W z IE 1 .00 IN N 11LF ig"O 1.5": • - p g il I ami `' i- 14 .7 OUT /bo' �i CD 0 W/LOCK L Q W t F.77."01.5X z l "IM = 14 .45 O (n I I M wti •,•'. lE = 145 03 0 Ja Q .,a - W cn w NI: .. 11111111111111111111. ---i 8L --'s..� .. w..w.w+w� F... 1/2, NW 1/4 \ mLi) 411 S 4_R-5E, W.M. 3 cc) Q Q I inch = 30 ft. APARTMENTS 00' BOARD Evct - N88.58'52111 , ` r 3123059153 STM CB#5 N88.58'52" 249.36' _ / I I eNCE CORN IS -TYPE I S46'16'W 1.35' RIM = 149.3 STM CB#4 IE = 146.3 TYPE I RIM = 149.3 IE OUT = 146.21 1 t� COPPER RIDGE APARTMENTS KC PARCEL NO. 3123059153 I () A. CORE AND SPECIAL REQUIREMENTS ANALYSIS This section of the TIR is intended to meet agency specific requirements for a report addressing all Core and Special Requirements of the 2005 King County Surface Water Manual and the Renton Surface Water Manual Addendum. Core Requirement 1. Discharge at the Natural Location The discharge location from the existing and developed site is identical. Currently,the site slopes westerly at up to 19%. General drainage patterns run from the site toward the adjoining multi-family development on parcel 3123059153. A 50 foot dispersal trench will release drainage near the westerly property line. A 12 inch diameter storm pipe is stubbed to the westerly property line,but there is no easement and the adjacent property owners have refused to allow the development to connect to this line by refusing to grant the easement. Core Requirement 2. Offsite Analysis A level one-offsite analysis is required and is provided in section III of the Technical Information Report(TIR). Core Requirement 3: Flow Control Per City of Renton Flow Control Applications Map, the site lies in a Conservation (level 2) flow control area. A detention tank is proposed to mitigate increased storm water runoff Porous concrete is proposed for much of the impervious road and driveway surfaces. Storm water modeling is achieved using Washington State Western Washington Hydraulic Model (WWHM3) since it facilitates modeling porous concrete surfaces and is recommended by the Washington State Low Impact Development Manual (2005). Section 1.2.3.3 (KCSWM pg 1-44)requires flow control BMP's be applied to individual lots. Per Section 5.2.1.3, and Table 5.2.1A, since the lot is greater than 22,000 s.f. and the impervious fraction is greater than 45%(approximately 66%for this project)then Large lot/High impervious bmp's are required. Normally,Full Dispersion,(see KCSWM Appendix C,page C-24) is required,but since this site is small and will be densely developed,the required native growth flow lengths are not available. If full dispersion is not possible,then full infiltration must be used if feasible(see pg. C-38). Feasibility is based on the presence of 4 to 6 feet of cobbles,coarse or medium sands which are not indicated in the project geotech report. The Geotechnical Engineering Study by Pioneer Engineering, Inc.,page 4, dated 7/3/07 (see appendix) indicates "The...soils are generally...not in support of stormwater infiltration." Limited infiltration(per KCSWM Appendix C.2.3 is also not feasible given the character of the soils. The project geotech report indicates the soils conditions as 8-12 inches of topsoil...underlain by 18 to 22 inches of fill underlain by Ablation and Lodgement Tills, medium dense with oxide staining indicative of perched groundwater conditions. Although KCSWM generally allows infiltration in fill if it was placed in accordance with geotechnical recommendations and percs greater than 8 inches per hour,this fill was placed long ago under unknown conditions. Therefore, site and/or roof downspout limited infiltration is not suitable for the site. If full roof dispersion nor full infiltration is feasible,then mitigation BMPs must be applied. (See pg. 5-6 and C-14, including a selection of limited infiltration(pg C-23),basic dispersion(pg. C- 49-51),rain garden, pervious pavement, rainwater harvesting or reduced site impervious coverage covenants and native growth credits. (pg 5-6 and C-52 to C-71). Our conclusion for a BMP design strategy is that since full dispersion and full infiltration and limited infiltration are not possible, we propose to provide permeable pavement(porous concrete pavement)on 8, 661 square feet. Table 5.2.1A requires BMPs on 10%of the 41,382 s.f. site or 20%of the 27,486 s.f. target impervious area whichever is less. This goal is met at 20%of the site and 31% of the target impervious area. A second geotechnical report by Pioneer Engineering, Inc., dated 12/6/2010 was done in support of the use of porous concrete pavement(PCP) and determined relative infiltration rate 10.11 in/hr, including a safety factor of 3 (measured 0.33 in/hour). Roof drains will be tight-lined to the detention tank. See Section IV of the TIR for details. Core Requirement 4: Conveyance System A conveyance analysis is included in section V. Core Requirement 5: Erosion and Sedimentation Control Preliminary Erosion Control Systems are recommended in Section IX of the TIR. A CSWPP is also provided in Section IX. A separate ESP Plan has been prepared for the Final Construction Document Phase. Core requirement 6: Maintenance and Operations A maintenance and operations manual sections has been included in Section X of the TIR. Core Requirement 7: Financial Guarantees and Liability The proposed project will include improvements to 130th P1 SW. Therefore, per paragraph 1 of KCSWM 1.2.7,financial guarantees are required and provided herewith. See Section IX. Core Requirement 8: Water Quality The Renton Surface Water Manual(Pg1-63)requires that runoff from multifamily projects must meet the enhanced basic water quality menu unless otherwise exempt. A Drainage Adjustment Application Letter is attached to the TIR(see Appendix)to request the City to allow the use of an enhanced water quality treatment exception specified in Section 1.2.8.1 (pg 1.-69)of the 2009 KCSWDM. The project is vested to the 2005 KCSWDM;however,the 2009 manual added an exception#4 in Core Requirement No.8 which allows commercial projects to reduce the enhanced water quality treatment requirement to basic water quality treatment provided they meet the conditions therein. Per the 2009 KCSWM,section 1.2.8.1 (pg 1-69)Exceptions: 4.The Enhanced Basic WQ menu as specified above for treating runoff from a commercial land use may be reduced to the Basic WQ menu if all of the following criteria are met: a)No leachable metals(e.g.,galvanized metals)are currently used or proposed to be used in areas of the site exposed to the weather,AND b)A covenant is recorded that prohibits future such use of leachable metals on the site(use the covenant in Reference Section 8-Q),AND c)Less than 50%of the runoff draining to the proposed treatment facility is from any area of the site comprised of one or both of the following land uses: •Commercial land use with an expected ADT of 100 or more vehicles per 1,000 square feet of gross building area. •Commercial land use involved with vehicle repair,maintenance,or sales. The project proposes no leachable metals exposed to weather(note potential galvanized metal storm drains must have treatment 1 asphalt lining inside and out). A covenant prohibiting leachable metals is included in section IX. None of the runoff draining to the proposed treatment facility is from a commercial land use(the site is multi-family) nor from a commercial land use involved with vehicular repair,maintenance or sales. Although the site is Mult- family,for traffic comparison purposes,ADT for the site is approximately 144(based on 8 vehicles/day/home, ASSHTO Trip Generation Manual). The total square footage for each unit is approximately 2000 square feet,and there are 18 units so there is 144ADT/(2x18)=4 vehicles/1000 square feet of building area which meets the requirement. The Drainage Adjustment Application Letter also requests the City to allow the use of a Stormfilter ZPG media cartridge basic water quality treatment facility as specified in Section 6.1.1 (pg 6-5)of the 2009 KCSWDM. Additionally,the Drainage Adjustment requests the City to allow the use of a CDS concentrator made by Contech® for use as pre-treatment for the proposed stonnfilter ZPG media cartridge system The City indicated in prior conversations and 5/26/11 e-mail from Allen Quynn,Renton Project Manager,that they would consider these aforementioned adjustments provided the proponent can demonstrate that the project meets the requirements specified under Section 6.2 of the City of Renton Amendments to the 2009 King County Surface Water Design Manual which allows the City,through an adjustment process,to consider treatment facilities that have been given a general use designation through the Washington State Department of Ecology's Technical Assessment Protocol—Ecology(TAPE)program. The Department of Ecology has given CDS a general use designation for pretreatment(see appendix). The Drainage Adjustment Application to the Renton Development Services Division addresses the following: 1. Produces a compensating or comparable result that is in the public interest,AND 2. Meet the objective of safety,function,appearance,environmental protection and maintainability based on sound engineering judgment. Hagenson Consultants response to the above conditions is as follows: The proposed water quality system produces a compensating or comparable result that is in the public interest. The 2009 KCSWM includes water quality treatment methodology and technology that has evolved since the 2005 KCSWM. Projects with relatively low trip generation and automotive use(compared with high use retail sites)are now known to generate lower levels of heavy metals and other pollutants and are therefore eligible for exception from enhanced basic water quality requirements. The ZPG media cartridge system has been adopted by the 2009 KCSWM after extensive testing and has been accepted as demonstrating adequate performance to meet the Basic Water Quality Performance Goal of removal of 80%of TSS(total suspended solids)per 2009 KCSWM 6.1.1 (pg 6.4). yp) The CDS concentrator made by Contech®for use as pre-treatment has been demonstrated to meet the KCSW pretreatment performance goal of 50%removal of TSS(2009 KCSWM 6.5.1,pg 6-103). This performance level is documented in"General Use Level Designation for Pretreatment(TSS)for Contech Construction Products,Inc. CDS System"(see Appendix). It should be noted that the CDS concentrator is approved for pretreatment use by the Washington State Department of Ecology to meet the requirements of their current stormwater manual. The proposed water quality system meets the objective of safety,function,appearance,environmental protection and maintainability based on sound engineering judgment. 1. Safety. The system consists of below grade manholes with standard accessibility and presents no greater safety dangers than comparable devices which are accepted under the current storwmater code. 2. Function. As addressed in the above discussion,the proposed system meets the treatment goals. 3. Appearance. Since the systems are below grade,they appear as manhole covers and do not differ from comparable accepted devices. 4. Environmental protection. Since their function is"environmental protection"and the proposed system meets the treatment goals,there is no reduction in environmental benefit. 5. Sound Engineering Judgment. The proposed system is accepted in either the 2009 KCSWM and/or the current Washington State DOE Stormwater Manual. Special Requirement#1: Other adopted area-specific requirements. The site is located in the Panther Creek sub-basin of the Black River Basin. Special Requirement#2: Floodplain/Floodway delineation The project does not contain nor is adjacent to a stream, lake,wetland or closed depression. The project is not listed in a floodplain per FEMA mapping. Therefore,this requirement does not apply to the site. Special Requirement#3: Flood Protection Facilities The project contains no streams nor flood protection facilities. Therefore,this requirement does not apply to the site. Special Requirement#4: Source Controls Commercial, industrial and multifamily projects are subject to this requirement and must meet the requirements of the KC Storm water Pollution Prevention Manual. Activity Sheet A-8 of the KCSPPM requires that solid waste and food waste is stored in a leak proof container with solid lids and that the vessels are inspected for leaks periodically. Garbage service will be provided by the City of Renton and the vessels will be provided and inspected and replaced as necessary by them. • I. PROJECT OVERVIEW The Proposed Development consists of an 18 unit townhome project located at 4701 Talbot Road South approximately 0.95 acres. Existing Zoning is RM-F. The proposed residential development does not require Frontage Road Improvements since the road is fully improved with curb,gutter and sidewalk.Site design criteria are based on the 2005 King County Storm Drainage Manual along with the City of Renton Surface Water Manual Addendum as adopted by the City at the time of the pre- application conference. IL PRELIMINARY CONDITIONS SUMMARY The property has an existing single-family residence with landscaped yard. The house and all site improvements will be demolished with the exception of the existing retaining wall lying on the easterly property line. Existing grades slope generally towards the west at about 10% average. Drainage from the site is sheet flows westerly onto the adjoining multi-family parcel and then travels to the westerly in pipe conveyance systems to SR 167 Panther Creek drainage system. Site slopes vary between 2 and 12 percent. Site soils are classified in SCS mapping as Alderwood gravelly sandy loam (AgC), 6 to 15% slopes, hydrologic class C, till soils. Alderwood series have slow permeability;runoff potential is slow to medium and a moderate to server erosion hazard.There are no indications of closed depressions on the property. A review of available information indicates there are no floodplains, wetlands, aquifer protection areas,liquefiable soils,steep slopes,erosion hazards,landslide hazards nor coal mine hazards on the site nor in the immediate area. ____ `-=~ ___- t j :/ \I\ 1 -Center ,,,,,7/ . 1:,— 11:<>1 : 's 1 ' / ii %, S 180th St S 43rd St , co , :alb / ,,.___I--__7--, I i ,, __.. / /// 1/e,4.//4:1 Il ii-i 11' (...____ s 45ii_cor , . ____11-4117 //:, i ( I___ ii k)" S 47th St 0 IL / -I _ ilt__.-------//— -' * --' ncor-4 i _ SE 185th PI / / ,/,..r.,.._lir___1( 1 6---4 Ili Fis•t ...__. il) __.54 I (44- 1 r ' t. , 1r( ( ----.'-g-- `- / I > j - / / �- � / --��1� x�`"U7 �ooy�' Umpd�u@2O07H�VTEU`* -�� �| - King County Districts and Development Conditions for parcel number 3123059090 Page 1 of 2 IF HOME NEWS SERVICES DIRECTORY CONTACT i Search KCGIS Center King County , Always at your service www.KingCounty.gov/GIS KCGIS Parcel Reports King County Districts and Development Conditions for parcel Districts and Development 3123059090 „`" Conditions Report Find Your Council District Parcel number 3123059090 Drainage Black River -� ` Find Your Watershed Address — Not Basin ' _ -- Available Available Watershed Duwamish .-ire„ W KCGIS Center Jurisdiction Renton River Zipcode 98055 WRIA Duwamish-Green L Kroll Map page 603 —PLSS SE-31-23-5 I Thomas Guide 686 Latitude 47.43728 ti page — King County GIS Center Longitude -122.21366 f} , King Street Center t r � - 201 S.Jackson St. e 'r, Suite 706 �r='', Seattle,WA 98104 11 giscenter(a)kingcounty.gov . ; 1 I +47.59909 N -122.33136 W Electoral Districts +47° 35'56.72" Voting district RNT 113535 Fire district - does not apply -122°19'52.90" King County Council district District 5,Julia Water district does not apply Patterson Sewer district does not apply (206)296 1005 1= i Water&Sewer district does not apply Parks&Recreation does not apply Congressional district 9 _ district Legislative district 11 Hospital district Public Hospital District School district Renton#403 No.1 Seattle school board district does not apply(not in Rural library district does not apply Seattle) Tribal Lands? No District Court electoral district Southeast — King County planning and critical areas desi•nations King County zoning NA,check with Water service planning area does not jurisdiction apply P-Suffix conditions None Roads MPS zone 340 ' Comprehensive Plan Transportation Concurrency does not ------------ Urban Growth Area Urban Management apply Unincorporated Area Council does not apply Forest Production district?-__—`_ No Agriculturaldistrict? No Creek Production n Ck _ _ _ Community Planning Area soo __ Coal mine hazards? None mapped Rural clearing limits apply? __ No Erosion hazards? None mapped Critical aquifer recharge area? None Landslide hazards? None mapped — — ppm 100-year flood plain? None Seismic hazards? None mapped mapped Wetlands at this parcel? —_ — None mapped http://www5.kingcounty.gov/kcgisreports/dd_report.aspx?PIN=3123059090 8/19/2010 King County Districts and Development Conditions for parcel number 3123059090 Page 2 of 2 ` 19 Related resources King County Assessor:.9Real Property Report King County Assessor:Quarter Section Map (PDF format requires Acrobat) King County DDES: (for unincorporated areas only) King County Treasury Operations:Property Tax Information for this property King County Recorders Office: King County Recorders Office:Scanned images of surveys and other map documents. Open iMAP to this property (requires a high speed intemet connection) Open Parcel Viewer to this property (any connection speed,but less features than iMAP) Search Address or parcel number: Go I Reset ❑ search by condo name example address:8621 428TH AVE SE I example parcel number:0942000860 This report was generated on 8/19/2010 5:51:11 PM Home Privacy I Accessibility I Terms of use I Search Contact us at giscenter(a)kingcounty.gov. Links to external sites do not constitute endorsements by King County.By visiting this and other King County web pages,you expressly agree to be bound by terms and conditions of the site. ©2010 King County http://www5.kingcounty.gov/kcgisreports/dd_report.aspx?PIN=3123059090 8/19/2010 Icing Uounty Department of Assessments: eReal Property Page 1 of 2 f\OS HOME NEWS SERVICES DIRECTORY CONTACT Search c. 9c�,t.; King County Department of Assessments Awan atY""zur°-e Fair,Equitable,and Understandable Property Valuations 111111111111111111111111 You're in:Assessments»Online Services»eReal Property SHARE Home --- - ----- New Search Property rax Bill I Map This Property[Glossary of TermsT Area ReportJ PropertyDetail Quick answers L._.._ ._._ Reference Links: Property tax assessments Taxpayer assistance PARCEL • King County Taxing Districts Codes and • Online services Parcel Number 312305-9090 Levies(.PDF) Reports.data Name ORION INVESTMENTS LLC Forms Site Address • King County Tax Links News room Legal E 300 FT OF N 1/2 OF N 1/2 OF N 1/2 OF NW 1/4 OF SE 1/4 LESS CO RD • Property Tax Advisor Contact us BUILDING 1 • About us • Washington State Year Built 1963 Department of Site map Building Net Square 2850 Revenue(External Footage link) Department of Construction Class WOOD FRAME • Washington State Assessments Board of Tax 500 • Fourth Avenue. Building Quality AVERAGE Suite ADM-AS-0708. Appeals(External Seattle,WA 98104 Lot Size 44866 link) - Present Use Single Family(Res • • Office Hours: Use/Zone) • Board of Mon..Tue.,Wed..Fri Appeals/Equalization 8:30 AM to 4:30 PM Views N Thu.9:30 AM to 4:30 PPA Waterfront • Districts Report TEL:206-296-7300 TOTAL LEVY RATE DISTRIBUTION • iMao FAX 206-296-5107 -- - TTY:206-296-7888 • Recorder's Office Tax Year:2010 Levy Code:2100 Total Levy Rate:$11.12066 Total Senior Rate:$7.30275 • Send us mail Scanned images of ,_,.,,,,1.*,,.s1 ;,,._, surveys and other 1 i map documents Hcspaat.0.53290 4.79,', • EMS.C.30000.2.10% Flood.0.10 514.0-95`1'. I ferry.0.70348-0.02% City.2.71184.24.39% • COnsoridatcc..`.211.9.33.48'%, 34.33%Voter Approved TAX ROLL HISTORY Valued Tax Appraised Land Appraised Imps Appraised Taxable Land Taxable Imps Taxable Year Year Value Value Total Value Value Total 2010 2011 $358,900 '$48,100 $407,000 $358,900 $48,100 $407,000 2009 2010 $358,900 $53,700 $412,600 $358,900 $53,700 $412,600 2008 2009 $129,000 $228,000 $357,000 $129,000 $228,000 $357,000 2007 2008 $123,000 $205,000 $328,000 $123,000 $205,000 $328,000 2006 2007 $123,000 $205,000 $328,000 $123,000 $205,000 $328,000 2005 2006 $123,000 $205,000 $328,000 $123,000 $205,000 $328,000 2004 2005 $72,000 $207,000 $279,000 $72,000 $207,000 $279,000 2003 2004 $72,000 $207,000 $279,000 $72,000 $207,000 $279,000 I 2002 2003 $70,000 $193,000 $263,000 $70,000 $193,000 $263,000 2001 2002 $67,000 $170,000 $237,000 $67,000 $170,000 $237,000 2000 2001 $64,000 $153,000 $217,000 $64,000 $153,000 $217,000 1999 2000 $60,000 $131,000 $191,000 $60,000 $131,000 $191,000 1998 1999 $57,000 $111,000 $168,000 $57,000 $111,000 $168,000 1997 1998 $0 $0 $0 $52,000 $103,000 $155,000 1996 1997 $0 $0 $0 $36,000 $103,400 •$139,400 1994 1995 $0 $0 $0 $36,000 $103,400 $139,400 1992 1993 $0 $0 $0 $42,000 $103,400 $145,400 1990 1991 $0 $0 $0 $38,500 $94,900 $133,400 1988 1989 $0 $0 $0 $30,600 $69,500 $100,100 1986 1987 $0 $0 $0 $32,400 $61,100 $93,500 1984 1985 $0 $0 $0 $26,000 $62,800 $88,800 1982 1983 $0 $0 $0 $26,000 $62,800 $88,800 Updated:July 9,2010 http://info.kingcounty.gov/Assessor/eRealProperty/Dashboard.aspx?ParcelNbr=3123059090 8/19/2010 i . 'r.Y .Kf 5- �- d� �f Y 3 i f r fe- ,P &' t a i Ilr • w N e. , ff P 1 .i , a t y� . .� 9 tC ,� - _ 2 �r l i' :/// 7. t Ti, { � 1. ,j b n 4 'y ' ` '''' NI W.�" M ..->a..u�.,Ay.. 'x _..._:,:„.i,,,/.... , .„ , , , , 4., I. ♦ f t . -. - 1 w-i+,4 � ' - jLL ,_4. IIII ! '...,.1,f^a us'rw;»w, 'erR j L 551. —� t�" L Iiiiii.Mnli iC.I 2310 King Counly.. fes _ c; 37y i U f!jogger btjpoljodaef elpold:jt In bqli bt!cf f o!dpn gjrhelcz!Ljoh!Dpvotz!t rbgjgpn Ibhnbgf i!pgt pvedf t l boeljt!1 vclf dJrp!d bohf!xju pvuopydf/ILjoh Dpvotz!n bl f t lop!sfqsf t f:otbtjpot!prix bszbot$t-If ygsf t t I psjn mil e-!bt hpl bddvd3dz-!dpn J!Lquilt of t t-!yn f oaf t t-!puyhi J hp!u f!vt f!pgt vci yowl bypo/ U jt!epdvn f oujt!opdjod oef elgostvtf!bt!b!tvenf z!gfpevc joh!Dpvotz!t i brdopdcf lybcrh!grslboz!hf of Matt of dlbnljoel9 du!jodjef ocbnlp9dpotf rvf oybm . 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''-t'''' ry r4 — -a £` 4. 7 -ie _-.;:4.R'"1 sk r Ren LO fIS I „:4,,,_`.•.,,t,,,,,„,,,4_,:- _.1,1i ':' •.... { y.. + j � ! mY'� Fig 1 jq 'IV { -2 i' -...4;;3,-._- -.1.t.1,-..4,-.,....:4„_04., 5 j jpi 9r 4' _ort �`#? t74'.y ..•7-.--...v..47,7::-.:.7.- 'r ="17...1.4.-.. 7,: 4'. 4, C'-'4.' • I.' — --.22 ,ws� r IS..Ss lS ix 1 - y .' •,.4.0,,,,,s.-°' r l�•k11 T 1 _ ri -,..-0 ::: se' . IA 'fi` } 4 t . 1• iiIIR 4 Ft” aa. h k' ..-;:r"..,;',:'''''',.-IF,:. :.,W i. ' �Y `.: 't� yx t ; � ,WS- arty .. Y S ■ ..... aufat.+ ._,.. ,,,..,.. $Pi {C12010KmgCovnly.?;,�Yi ....___ . . ..,..\, . ....,,_.4,,,,,...,, ,.i.1, 9.. J�, ... -- ��. _4, _2 , - t ti' ",", itr ik:air: •�1 ,� pn --.e-��.�...� _ ��_ ��The information included on this map has been compiled byKingCount staff from a vane of sources and is subrect to change without notice.King' County makes no representations or warranties,express or implied,as to accuracy,completeness,timeliness,or rights to the use of such information. This document is not intended for use as a survey product King County shall not be liable for any general,special,indirect,incidental,or consequential a damages including,but not limited to,lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of King County this map or information on this map is prohibited except by written permission of King County. Date:8/19/2010 Source:King County iMAP-Property Information(http:f/www.metrokc.gov/GIS/iMAP) i MAP Legend M. Highlighted Feature Parcels ! R 98 Re5Klenttai.48DU oar acre I -� County Boundary n Parks 'a0 - Nctghtsarhaee Business L_I x Mountain Peaks Unincorporated KC Zoning CB •-CommunityBusiness Highways A,10-Agricutturai.ane DU per 10 acres j RB Ragtunal business Forest Production District , A-35-Agrecutturat.ana DU mar 35 ares Boundary F Forest I-industrial Agricultural Production M • MI metal .I °Mer District Boundary RA-25-Rural Area.-anti DU per 5acres 2007 Color Aerial Photos 1..6inI RA 5 Rural Area.ana DU oar5acres 2007 Color Aerial Photos i.12in) pf Urban Growth Area Line RA•10• Rural Area.one DU per 10 acres Incorporated Area UR Urban Resets.one DU per 5 acres Streets R-1 -Restdentwl.one DU per acre Highway R•4 Resilential.4 DU per acro Astlrrais R-6•Residents 6 DU per acre Local R•9•Ressutent at.9 DU per acro Lakes and Large Rivers R•12 Resent tat.12 0 U per acre Streams i 5,18• Residential.18 DU per acre Tribal Lands R.2l-Residentsal.24 DU per acre (cont( ( 1 -The information included onthis map has been compiled by King County staff from a variety of sources and is subject to change without notice.King County makes no representations or warranties,express or implied,as to accuracy,completeness,timeliness,or rights to the use of such information. This document is not intended for use as a survey product.King County shall not be liable for any general,special,indirect,incidental,or consequential a damages including,but not limited to,lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of King County this map or information on this map is prohibited except by written permission of King County. Date:8/19/2010 Source:King County iMAP-Property Information(http://www.metrokc.gov/GISAMAP) 3 III. OFF-SITE ANALYSIS (LEVEL ONE DOWNSTREAM DRAINAGE ANALYSIS) OFFSITE DRAINAGE ANALYSIS Task 1 (2005 KCSWM Pg 2-10) Study Area Definition and Maps The study area extends from the site to 1/4 mile downstream from the site as shown on the included mapping. A parcel report and map are included as well as Imap topography,City of Renton Storm Drain Inventory Mapping,and Imap drainage complaint mapping. Task 2 Resource Review - Basin Plans-A check with Public Works Staff indicates there is no Panther Creek Basin Plan. - Drainage Studies-No specific studies were available at the time of this report. - Basin Reconnaissance Summary Reports—None Available. - Critical Drainage Areas-A review of online mapping and Public Works Resource Mapping indicates there are none for this area. - FEMA maps—A review of FEMA mapping indicates no floodplain within the study area. - Other Offsite Analysis Reports-A check with Public Works Staff indicates there are none for this area - Sensitive Areas Folio—Imap Sensitive Area Mapping is included herewith and there is nothing noted within the study area. - DNRP Drainage Complaints and Studies-A review of King County Imap and discussions with Public Works indicate there are no downstream drainage complaints within'/ mile downstream. Since none were available,no specific complaints were obtained based on their proximity to and/or location within the study area,as well as their specific dates(note complaints older than 10 years are not included per footnote,page 2-11)nor was a summary table included at the end of section. - Road Drainage Problems.None reported other than those listed under drainage complaints. - USDA SCS soils mapping. The Geotechnical Engineering Studies by Pioneer Engineering,Inc.dated 7/3/07 and 12/3/10 indicates about 2 to 3 feet of fill over much of the site underlain by till soils with very light groundwater evidence in some exploration holes at about 3 feet of depth. Site soils are classified in SCS mapping as Alderwood gravelly sandy loam(AgC),6 to 15%slopes,hydrologic class C,till soils. Alderwood series have slow permeability;runoff potential is slow to medium and a moderate to server erosion hazard. - Wetlands Inventory—none noted in Imap. - Migrating River Studies—None reviewed,no river in proximity. Task 3 Field Inspection Field Inspections were performed on February 9,2010. Weather conditions were clear skies. Task 4 Drainage System Description and Problem Description The upstream area lying generally east of the site consists of fully developed Talbot Road South with curb,gutter and storm drains. Drainage from these upstream areas is collected and conveyed in the street storm system, such that the site constitutes the top of the sub-basin. Therefore, it is evident that normal precipitation on the upstream areas do not impact the site in neither its' existing nor developed condition. A review of the City's Website,City Public Works 5th floor Resource Maps,and King County Imap shows that the study area lies within the Panther Creek sub basin of the Black River. 25) Hagenson Consultants conducted a field reconnaissance on February 9, 2011 to conduct field observations and report any substantive issues with regard to the downstream conditions. Our reconnaissance included inspection of the downstream drainage network for a distance in excess of '/ mile. The system consists of 12" to 24" diameter storm pipes, catch basins and open channel ditches with ditch depths varying between 2 and 3 feet. We observed no evidence of flooding, scouring, erosion or deposition, other than normal sediment deposition in catch basins. An offsite Analysis Drainage System Table(98 KCSWM ref 8-B) is included summarizing findings Research of current drainage complaints or problems for the downstream area included review of KC I-map drainage complaints and a meeting with City Public Works engineer Mr.Gary Fink to review City drainage complaint records. No complaints were found and a copy of the Imap and an e-mail from Mr. Fink are included to substantiate this finding. Task 5 Mitigation of Existing or Potential Problems. Our conclusions are. (1)Continued maintenance of the existing public storm drains is important to prevent future flooding. (2) Meeting the storm water flow control and water quality code requirements can effectively mitigate impacts from proposed developments. This practice effectively limits flows and pollutants to pre-developed levels.(3)Installation of a dispersal trench will mimic existing sheet flow patterns. DDW1ki S►f aj ALJALisis Mar'PiJii2 Z[ C) tv is. isig I3NE - 31 11. P14575 ,.. ___ / 1440! 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Subbasin Number: Symbol e Drainage _. g Slope Distance Component Type, Existing YP , Component Potential Observations o field Name and Size from site Problems Problems see mapDescri.tion dlschar,a inspector, resource Type:sheet flow,swale, drainage basin,vegetation, ° 'A reviewer or resident stream,channel,pipe, cover,depth, �0ml=1,320 ft. constrictions,under capacity,ponding, pond;Size:diameter, P type of sensitive overtopping,flooding,habitat or organism tributary area,likelihood of problem, surface area area,volume g overflow pathways,potential impacts destruction,scouring,bank sloughing, 11\ nillIllIllIllIllIl sedimentation,incision,other erosion 1lM IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII INIMI S►4rC—TFLptN GRAsS Ip 7C), NIWE _S C bt)R LIS PERSAL Tea-1RM K eat). a ' C 12" TO IS"_0'50 CDAILRETc t CMP ! roln 1100' c- � I g"Tb 2f"-kr-5-0 - ALU6611�v ±ISAc 771/f3 AQr+,q CONCPE>; d LMP 21'O401. 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Henninger Subject: Drainage Complaint History- Renton Parcel#3123059090 Good Afternoon Hal, Thank you for coming in this afternoon. I am sending this e-mail as confirmation of our investigation of drainage issues within a%mile radius of Renton parcel#3123059090, located at 4701 Talbot Rd S. A review of King County and City of Renton drainage complaint records indicate no reported drainage issues within this area. Please feel free to contact me if you have further questions. Best Regards, Gary Fink City of Renton Utility Systems Division - Surface Water Utility Phone:(425)430-7392/Fax:(425)430-7241 GFink(a,RentonWa.gov Lity of r I r 1 IV. PROPOSED DRAINAGED IMPROVEMENTS Flow Control Per City of Renton Flow Control Applications Map.,the site lies in a Conservation (level 2) flow control area. A detention tank is proposed to mitigate increased storm water runoff. Porous concrete is proposed for much of the impervious road and driveway surfaces. Storm water modeling is achieved using Washington State Western Washington Hydraulic Model (WWHM3) since it facilitates modeling porous concrete surfaces and is recommended by the Washington State Low Impact Development Manual(2005).The porous concrete areas are modeled as a separate infiltration pond with a bottom area equivalent to the area of the paving and a storage volume based on the void space in the sub-base and porous concrete which is equivalent to the depth of paving and sub-base rock x 20%. The model then accepts overflow for the design storms from the porous concrete (if any) and combines it with the impervious areas and routes it through the detention tank. Catch basins are added in the porous concrete areas as necessary to insure that any overflows are intercepted and conveyed to the storm water detention system. Software provided by the porous concrete paving institute was used to design the porous concrete paving section (see attached in appendix). Section 1.2.3.3 (KCSWM pg 1-44)requires flow control BMP's be applied to individual lots. Per Section 5.2.1.3, and Table 5.2.1A, since the lot is greater than 22,000 s.f and the impervious fraction is greater than 45%(approximately 66%for this project)then Large lot/High impervious bmp's are required. Normally,Full Dispersion, (see KCSWM Appendix C,page C-24) is required, but since this site is small and will be densely developed,the required native growth flow lengths are not available. If full dispersion is not possible,then full infiltration must be used if feasible (see pg. C-38). Feasibility is based on the presence of 4 to 6 feet of cobbles, coarse or medium sands which are not indicated in the project geotech report. The Geotechnical Engineering Study by Pioneer Engineering,Inc.,page 4, dated 7/3/07 (see appendix) indicates "The...soils are generally...not in support of stormwater infiltration." Limited infiltration(per KCSWM Appendix C.2.3 is also not feasible given the character of the soils. The project geotech report indicates the soils conditions as 8-12 inches of topsoil...underlain by 18 to 22 inches of fill underlain by Ablation and Lodgement Tills, medium dense with oxide staining indicative of perched groundwater conditions. Although KCSWM generally allows infiltration in fill if it was placed in accordance with geotechnical recommendations and percs greater than 8 inches per hour, this fill was placed long ago under unknown conditions. Therefore, site and/or roof downspout limited infiltration is not suitable for the site. If full roof dispersion nor full infiltration is feasible, then mitigation BMPs must be applied. (see pg. 5-6 and C-14, including a selection of limited infiltration(pg C-23), basic dispersion(pg. C- 49-51),rain garden,pervious pavement,rainwater harvesting or reduced site impervious coverage covenants and native growth credits. (pg 5-6 and C-52 to C-71). 2(; Our conclusion for a BMP design strategy is that since full dispersion and full infiltration and limited infiltration are not possible, we propose to provide permeable pavement(porous concrete pavement)on 8, 661 square feet. Table 5.2.1A requires BMPs on 10%of the 41,382 s.f site or 20%of the 27,486 s.f target impervious area whichever is less. This goal is met at 20%of the site and 31%of the target impervious area. A second geotechnical report by Pioneer Engineering,Inc., dated 12/6/2010 was done in support of the use of porous concrete pavement(PCP)and determined relative infiltration rates of 0.11 in/hr, including a safety factor of 3 (measured 0.33 in/hour). Roof drains will be tight-lined to the detention tank. Installation of a dispersal trench for stormwater outflow at the property line will mimic existing sheet flow patterns. The applicant approached the adjacent property owners to obtain an easement to connect to the existing 12"storm drain lying west of the proposed development,but was denied the easement. 100 year flows are less than 0.5 cfs, so a 50 foot long trench is used as recommended in the KCSWM Detail figure 4.2.2.N Water Quality Treatment The Renton Surface Water Manual(Pgl-63)requires that runoff from multifamily projects must meet the enhanced basic water quality menu unless otherwise exempt. A Drainage Adjustment Application Letter is attached to the TIR(see Appendix)to request the City to allow the use of an enhanced water quality treatment exception specified in Section 1.2.8.1 (pg 1.-69)of the 2009 KCSWDM. The project is vested to the 2005 KCSWDM;however,the 2009 manual added an exception#4 in Core Requirement No. 8 which allows commercial projects to reduce the enhanced water quality treatment requirement to basic water quality treatment provided they meet the conditions therein. (See Core Requirement 8 for additional discussion). The Drainage Adjustment Application Letter also requests the City to allow the use of a Stormfilter ZPG media cartridge basic water quality treatment facility as specified in Section 6.1.1 (pg 6-5)of the 2009 KCSWDM. Additionally,the Drainage Adjustment requests the City to allow the use of a CDS concentrator made by Contech® for use as pre-treatment for the proposed stormfilter ZPG media cartridge system The proposed Water quality System,based on the Drainage Adjustment,consists of ZPG media cartridge system preceded by CDS concentrator made by Contech®for use as pre-treatment. 5.2.1 INDIVIDUAL LOT BMP REQUIREMENTS 11 FIGURE 5.2.1.A FLOW CHART FOR DETERMING INDIVIDUAL LOT BMP REQUIREMENTS Is the project on a sitellot Yesti . Is it feasible and smaller than 22,000 square feet? applicable to implement full Yes No further BMPs to Apply one or more of the following to impervious area 1 dispersion for the required. Note: roof area as per Any proposed >10%of site/lot for site/lot sizes<11,000 stand 220%ofSection C.2.1? connection of roof site/lot for site/lot sizes between 11,000 and 22,000 sf(For downspouts to projects located in critical aquifer recharge areas these No local drainage o impervious area amounts double): system mustaee 1. Limited Infiltration(Section C.2.3) Is it feasible via perforated • 2. Basic Dispersion(Section C.2.4) and applicable pipe connection 3. gain Garden (Section C.2.5) to implement per Section 4. Permeable Pavement(Section C.2.6) No full infiltration Yes C.2.11. • 5_ Rainwater Harvesting(Section C2.7) '.- 10.i frun the r of roof per No, 6. Vegetated Roof(Section C.2.8) A 7. Reduced Impervious Service Credit(Section C.2.9) Section C.2.2? 8. Native Growth Retention Credit(Section C2.10) 1 If Is the project on a site/lot 22,000 square feet Yes Is it feasible and or larger with impervious surface applicable to implement coverage of 45%or less? full dispersion on all YesImi No further BMPs target impervious required. Note: surface as per Any proposed connection of roof One or more of the following BMPs must be implemented Section C.2.1? downspouts to local No for that portion of target impervious surface not addressed Noi with full dispersion or with full infiltration of roof runoff: drainage system 1. Full Infiltration(Section C.2.2 or Section 5.4) Is it feasible and applicable to must be via — 2. Limited Infiltration (Section C.2.3) 41No implement full infiltration of perforated pipe 3. Basic Dispersion (Section C.2.4) the roof runoff as per connection per 4. Rain Garden(Section C.2.5) Section C.2.2 or Section 5.4? Section C.2.11. 5. Permeable Pavement(Section C.2.6) Yes Yes A 6. Rainwater Harvesting(Section C.2.7) ,� Is there any remaining target 7. Vegetated Roof(Section C.2.8) Is impervious not No 8. Reduced Impervious Service Credit(Section C.2.9) addressedpu with full surfacedispersion or 9. Native Growth Retention Credit(Section C2.10) with full infiltration of roof runoff? The project must be a sitellot 22,000 square feet Is it feasible and or larger with impervious surface ivapplicable to implement coverage of more than 45%? full dispersion on all target impervious No surface as per Projects with impervious area greater than 45%and equal to or '/ Section C.2.1? less than 65%one or more of the following must be applied to an impervious area greater than or equal to 20%of the site or 40%of Yes the target impervious surface whichever is less OR for projects greater than, 5%impervious one or more of the followingmust be No further BMPs applied to an impervious area greater than or equal10°/of site required. Note: or 20%of target impervious surface,whichever is : Any proposed 1. Full Infiltration (Section 5.4) connection of roof 2. Limited Infiltration (Section C.2.3) downspouts to 3_ Basic Dispersion(Section C.2.4) local drainage 4. Rain Garden(Section C.2.5) system must be _ Permeable Pavement(Section C.2.6) via perforated 6. Rainwater Harvesting(Section C.2.7) pipe connection 7. Vegetated Roof(Section C.2.8) per Section 8. Reduced Impervious Service Credit(Section C.2.9) C.2.11. 9. Native Growth Retention Credit(Section C2.10) 2005 Surface Water Design Manual 1/24/2005 5-11 i frt .Y '-'41;14,4:-`t!.;`1",4A 11 T Sii=`c arc t 4� t $ e �P1TS }/ 111 i / Na?�<nr y. s4''tr+i,1 "'t''‘'It.'"i. ._ I• .ip a- .Pt'. T, { R D �s ' -4011i, tr.-40 %, i r -..'.....':,:., 1 -- :,:i-, :4,..tr' \ 1 �e y7 ».Westin u,t �!— / : . A 41,0",e1.4or ' . . ' -', - -:-„, -111,1 '''' NONtiii ,,•....4,;,k, '' !, [ , 11, li .-- i , i 1,,,,,t,,4, ,, 4:.,_ mp**1-1 11 Nr-"v1 ' ' . r rr,... ;. .,.,..,. .,,,,,,,,,-;_.. ..;,..... .. ., 1 i.. 1 ,,,ws,.i. „,.. . .. ., i .t.,4.. , „ „7...,.„. , , , ....., ... „,„•,.... ,., .. . .,,:..,:,,, - ,„,:: ,. ,„ . i ! , ,,,,,,-.., .„ ...e.:, , - , . ,,,444,-,,, s 'S f .bmf ^5S 1 i .1i 'I . ,-*„,..t+, Y, \ . f i� � � A Opti 19Brc 3.2.2 KCRTS/RUNOFF FILES METHOD—GENERATING TIME SERIES ';3, I TABLE 3.2.2.B EQUIVALENCE BETWEEN SCS SOIL TYPES AND KCRTS SOIL TYPES SCS Soil Type SCS KCRTS Soil Notes Hydrologic Group Soil Group Alderwood (AgB,AgC,AgD) C Till >L Arents,Alderwood Material (AmB, AmC) C ? Till Arents, Everett Material (An) B Outwash 1 Beausite(BeC, BeD, BeF) C Till 2 Bellingham (Bh) D Till 3 Briscot(Br) D Till 3 Buckley (Bu) D Till 4 Earimont(Ea) D Till 3 Edgewick(Ed) C Till 3 Everett(EvB, EvC, EvD, EwC) A/B Outwash 1 Indianola (InC, InA, InD) A Outwash 1 Kitsap(KpB, KpC, KpD) C Till Klaus (KsC) C Outwash 1 Neilton (NeC) A Outwash 1 Newberg(Ng) B Till 3 Nooksack (Nk) C Till 3 Norma (No) D Till 3 Orcas(Or) D Wetland Oridia (Os) D Till 3 Ovall (OvC, OvD, OvF) C Till 2 _ Pilchuck (Pc) C Till 3 Puget(Pu) D Till 3 Puyallup (Py) B Till 3 Ragnar(RaC, RaD, RaC, RaE) B Outwash 1 Renton (Re) D Till 3 Salal (Sa) C Till 3 Sammamish (Sh) D Till 3 Seattle (Sk) D Wetland Shalcar(Sm) D Till 3 Si(Sn) C Till 3 Snohomish(So, Sr) D Till 3 Sultan(Su) C Till 3 Tukwila (Tu) D Till 3 Woodinville (Wo) D Till 3 Notes: 1. Where outwash soils are saturated or underlain at shallow depth (<5 feet)by glacial till, they should be treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King County DNRP shows bedrock soils to have similar hydrologic response to till soils. 3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water table. In the absence of detailed study, these soils should be treated as till soils. 4. Buckley soils are formed on the low-permeability Osceola mudtlkwv. Hydrologic response is assumed to be similar to that of till soils. 2005 Surface Water Design Manual 1/24/2005 3-25 SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS "_. � FIGURE 3.2.2.A RAINFALL REGIONS AND REGIONAL SCALE FACTORS ST 1.0 ST 1.0/ ST 1.1 _ LA 0.8 LA 0.9 LA 1.0 LA 1.2 E 1 -4M , . rt SNONOUISN Co UNIT .1:TI 1 _ I + JI;11 1--- PI' ; ' L. rf 0 Ti W REQ 0N,i1; I / ' 1, 5 ' q 1111, ,:i' ftim..• * 1144,17? 520 ,,k,Adl i 2 i AII • la. API_._ ,MILL J�I . . 1 Illpe; to LI • "l $ , f .I HAM i °ELI.EYAJE , w1/4, - - trrii,,,.„,„." - Ilk lam SEATTLE DD -\ , ; \ d!mromA17"-- lholk 1 v r:�r . i )►LV1Gr, �'� • — 1� .6G 't 1_ .`t r� 11 1iavail.,moll , . iiiiipo 1gNDndaor, I 1m 51, I----- Q �� k, Rs-, 1F2 � LANDSBURG 1 1!Et �. x sII5t— ' ' ll.11* s... IL ._ , ` �_M'Yt,,jS 4°- .tk\ ) .: , it- .k iii, ST 1.1 DD t la �; "'�► io 1 1 _ QI-dok 6 PIl NCE COUNTY 1 r ST 1.0 "° ST 1.0/ hr Rainfall Regions and LA 0.8 =4 1 Regional Scale Factors LA 0.9 - � LA =� Incorporated Areae LA 1.0 1.2 --c= River/Laken Major Road° ° 1/24/2005 2005 Surface Water Design Manual 3-22 6.4.1 WETPONDS—BASIC AND LARGE—METHODS OFANAL)MS ra IFIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES(FEET) ST 1.0 ST 1.0/ LA 1.2 ST 1.1 ,.... LA 0.8 LA. 0.9 LA 1.0 _ac S.COY«rr r F � {�i - "' fir--..iIry sd III r a at f1 litiC . r, 41,, ..,„,3 7,14. ilk 1111411A 1 rte� _�'a tl ; illiwo 11 5, 1 A/ 1L�116 ►"'T!✓.��i�. ..k._ir..4,44- 10,..v";,,t-- •seattF s, I. .. ,. ,�� � :5 !Wilk ximea'15' L Er ., �> i-�: i I :L Q am lel., i , __ iii/iiiiiki , 1. .!1' ‘ .71"latifrAlk = i' Illiti fl1111'41111.14 C:3 r'!�1 . JiI( 5') 1• (0.039') ilium Ilv'whi L=am Incorporated Area P .rte River/Lake 0.47" — Major Road (0.039') 0.52" ► INOTE:Areas east of the easternmost isopluvial should use 0.65 (0.043') 0.56" 0.65" inches unless rainfall data is available for the location of interest (0.047') (0.054') aE The mean areaal storm is a conoepttml storm found by dtvimn9 the annual Pin by the total number of dorm events per year result,generates large amounts of runoff. For this application,till soil types include Buckley and bedrock soils, and alluvial and outwash soils that have a seasonally high water table or are underlain at a shallow depth(less than 5 feet)by glacial till. U.S. Soil Conservation Service(SCS)hydrologic soil groups that are classified as till soils include a few B,most C,and all D soils. See Chapter 3 for classification of specific SCS soil types. 2005 Surface Water Design Manual 6-71 1/24/2005 8I-84ROAD "r® uff �1/4////l S7DQ/y DeTELITION VES141 ,4LDEI11.11 SD/LS - 71PE . 7/LL 5 riZS73Tr[s. i P2EDE%1EthP 0.9€AL-F0212ES7A-MIL,oStaPPt EY.<x <J6 '. POST Del ELD PED PEQ I/Ont Glass 141140 LAID SLADE = D, 31(1 AL 0.;19'AL c IMPEILdIIOS , ZDDF = 13.114 f- D .30LAL ' 1_ J i 5��L'.ZIjS•r 1� = 1(#?�f_ ) 9:7 ) r 506fD7 = _ 0.3$At Ro4DS = (0851P= 0,/3714j 1J210OuJarg = Casu * ; b.1 ,4 AL cAroTAL = 0,2g1A4. 1 M tbllr Fo_Acmo suttoft.114PLLll S= (7,0/AL o.b31/D.9S=10770 ToTp,L. = 0.q5,- P012,003 Ltilic12eirE ,AAD = 43I41= O.3q AL Pon.ag (9U[.JLe7 DQIUEw4q= 43471e, v, Dqq AL SuA772iJizi= O,Iggpc A•Srnm 1 Ave) IZoAr1 = 2vI PZo. = I Sogsf : (3.0354(. S1Ja.1D7K=7OiI . Peg, 40R14sr= G?• .02AL I I ;3P' _ f)r -T-A $.2.i.t�- ihurttr. 4171;u,L 10 8 of sl?E Q$l, Zo 0 14lA+r6vy I Pett'meth P40041c; = 0. fgbA { O'14tb/t1 q - 2 D. `ro of sirs / DIL o, /c1%,b3i = 1.4 90 6f k-er-i :eru ittav 1/614- , tong 97" 4ga/10w rvo (tufa/oL ) f ZS 'p = 31if1L r'IP?.d/j'/ 71631 o 1° -J/5 -111.7 sem/ r )1-? d 7'0 0 �� ' °/ ')107 0207d ill 71gf/71 14,07� c7 0200 .0 =71G) 0oh (tri-o2 log 2040 - 9!1,0474 :25 7 9491-9c'4g madolaA9a. �►e ,j •17a1 107-11075 37111. '0171`+ -11113 c7 m9 0(- 2946') 1111h! 9 e? I x /1-421,4.10371J,'73315 '11711t7 .cLWE7 1173V , !L I X ,,AI I , WPt1 71t011, (low kro j tys-v ) '?1h1�1,j rtmagi.aa 4i.. c Q /C! (VW 511 7JkI 9.1! 'mart bw?! Iwo? q/rl w¢ V t (hN 'X17 Q7 7d J,114j J'tr7 fl 47 5n0�0c1 -°LMj k tt' ganaffr1273Zl Nl/a? -14/11W II 'O fZr• ee '..'?f 3OQ& 91/ /ZI Z'lq.d' CJZI(15 51 1111/fYl if"0 = 321/111'1 - i (SORItil w)i f Sit ) 'QN /C 9 rwrsvv 7J4 31v)-91-e1517 3 y. ®tt'•'fT) 357110-) 9J r j L7.'0 = 41'4. =`/O Z X#11 =tIdalf Qr1od c-0-rQe1 . „cif c 1 x'0r"r 6t1 11075a:4 7/. J_ ?'hep CLFQA °I Q Z 141 3711 ( ' a17 ,i b n Q,wIv wyg7 s oucd 7130( "S Q10A 'k G Z /!VI 313-ir Iit7 5067164 -tadaa 'i L HJ. a- cerianui 1roonla Ts9Z01-0510)- ,tibxtih =35 /11 '5 =��71t1- W aifd T'WXZ 911T turn O ifiatIZUWJAit flV ytt ltd Nit any I ( 'v?b('0 = s I' h ) . V fl � �,W 0/7)Ijaw { ch urri ft 1 t-Ia JO monad tJ c -Tumittmi 0367Dow/s "7 .5 0, 3,2aCi t Wtl nit41 3a cr '5N15 c gnrFx4j aQI.1-111 a w mu. Qbo) � l and Use Report For 1 Developed Mitigated ervious Land Areas Basin 1 C- Lawn- Mod 0.319 apervious Land Areas 4 Basin 1 Basin #2 ROADS MOD 0.057 0.099 ROOF TOPS FLAT 0.302 DRIVEWAYS MOD 0.035 0.099 SIDEWALKS FLAT 0.038 . 1.7 :771 0.)1% 015 Western Washington Hydrology Model PROJECT REPORT coject Name: 1 ite Address: City sport Date : 2/11/2011 age Seatac Lata Start : 1948/10/01 Data End 1998/09/30 :ecip Scale: 1.00 i}Th 3 Version: 2EDEVELOPED LAND USE Name Basin tpass: No ..-roundWater: No arvious Land Use Acres Forest, Mod .95 Impervious Land Use Acres .ement Flows To: _irface Interflow Groundwater name Basin 1 Bypass: No :oundWater: No DQrvious Land Use Acres Lawn, Mod .319 Impervious Land Use Acres ZOADS MOD 0.057 )OF TOPS FLAT 0.302 .JAIVEWAYS MOD 0.035 SIDEWALKS FLAT 0.038 .ement Flows To: irface Interflow Groundwater Tank 1, Tank 1, —Me Tank 1 Tank Name: Tank 1 .mensions ..,epth: 9ft. Tank Type : Arched .dth : 14 ft. eight : 9 ft. Length : 80 ft. "'.scharge Structure a Q f+ rifice 1 Diameter: 0.875 in. Elevation: 6 ft. Element Flows To: "utlet 1 Outlet 2 Tank Hydraulic Table Stage(ft) Area(acr) Volume(acr-ft) Dschrg(cfs) Infilt(cfs) 0.000 0.000 0.000 0.000 0.000 .100 0.005 0.000 0.002 0.000 .200 0.008 0.001 0.002 0.000 u.300 0.009 0.002 0.003 0.000 0.400 0.011 0.003 0.004 0.000 .500 0.012 0.004 0.004 0.000 .600 0.013 0.005 0.004 0.000 0..700 0.014 0.007 0.005 0.000 ..- AP IIAK'OR 5 a. - 1,?S°lo X 29h(D,t44,71 = b.Do50S x.800 0.015 0.008 0.005 0.000 .900 0.015 0.009 0.005 0.000 I'"C EKY. 612t,,it IMO 4 b.7= l3$,9 z. .000 0.016 0.011 0.006 0.000 1.100 0.017 0.013 0.006 0.000 ' .200 0.017 0.014 0.006 0.000 .300 0.018 0.016 0.006 0.000 .400 0.019 0.018 0.007 0.000 1.500 0.019 0.020 0.007 0.000 " .600 0.020 0.022 0.007 0.000 .700 0.020 0.024 0.007 0.000 ..800 0.021 0.026 0.007 0.000 1.900 0.021 0.028 0.008 0.000 .000 0.021 0.030 0.008 0.000 .100 0.022 0.032 0.008 0.000 4.200 0.022 0.034 0.008 0.000 2.300 0.022 0.037 0.008 0.000 .400 0.023 0.039 0.009 0.000 .500 0.023 0.041 0.009 0.000 4.600 0.023 0.044 0.009 0.000 2.700 0.024 0.046 0.009 0.000 .800 0.024 0.048 0.009 0.000 .900 0.024 0.051 0.009 0.000 3.000 0.024 0.053 0.010 0.000 -1 .100 0.024 0.055 0.010 0.000 .200 0.025 0.058 0.010 0.000 .300 0.025 0.060 0.010 0.000 3.400 0.025 0.063 0.010 0.000 ' .500 0.025 0.065 0.010 0.000 .600 0.025 0.068 0.011 0.000 ,700 0.025 0.070 0.011 0.000 3.800 0.025 0.073 0.011 0.000 " .900 0.025 0.075 0.011 0.000 .000 0.026 0.078 0.011 0.000 2.100 0.026 0.081 0.011 0.000 4.200 0.026 0.083 0.011 0.000 300 0.026 0.086 0.012 0.000 400 0.026 0.088 0.012 0.000 4.500 0.026 0.091 0.012 0.000 4.600 0.026 0.093 0.012 0.000 700 0.026 0.096 0.012 0.000 800 0.026 0.099 0.012 0.000 4.900 0.026 0.101 0.012 0.000 5.000 0.026 0. 104 0.012 0.000 100 0.025 0.106 0.013 0.000 200 0.025 0.109 0.013 0.000 5.300 0.025 0.111 0.013 0.000 R 400 0.025 0.114 0.013 0.000 500 0.025 0.116 0.013 0.000 600 0.025 0.119 0.013 0. 000 5.700 0.025 0.121 0.013 0. 000 _ v .800 0.025 0. 124 3 0. 000 o.D(+2GF5 2yJL O** D� •41IAA.6c .900 0.024 0. 126 0.013 0. 000 F- IV SS- -_-_- mAL+ 5.9-- 144,12 .200 0.024 0.134 0. 023 0.000 .300 0.024 0.136 0. 025 0.000 0.400 0.023 0.138 0. 027 0.000 6.500 0.023 0.141 0. 028 0.000 .600 0.023 0.143 0. 030 0.000 .700 0.022 0.145 0.031 0.000 6.800 0.022 0.147 0.032 0.000 .900 0.022 0.150 0.034 0.000 .000 0.021 0.152 0.035 0.000 .100 0.021 0.154 0.036 0.000 7.200 0.021 0.156 0. 037 0.000 '.300 0.020 0.158 0.038 0.000 .400 0.020 0. 160 0.039 0.000 .500 0.019 0.162 0.040 0.000 b. 0401a.(5 7.600 0.019 0.164 0.041 0.000 --- 25 H(L 1Akli-plS(-ugllaG Eteu -;-.700 0.018 0.166 0.042 0.000 J .800 0.017 0.167 0.042 0.000 138.22 -7•4 1/45,0.2. -TIN, .900 0.017 0.169 0.043 0.000 04W.Afta4.. 8.000 0.016 0.171 0.044 0.000 .100 0.015 0.172 0.045 0.000 .200 0.015 0.174 0.046 0.000 0.300 0.014 0.175 0.047 0.000 8.400 0.013 0.177 0.047 0.000 .500 0.012 0.178 0.048 0.000 .600 0.011 0. 179 0.049 0.000 s.700 0.009 0.180 0.049 0.000 8.800 0.008 0.181 0.050 0. 000 .900 0.005 0.181 0.051 0. 000 .000 0.000 0.182 0.308 0.000 9.100 0.000 0.000 0.778 0. 000 Me Basin 2 Bypass: No roundWater: No Pervious Land Use Acres npervious Land Use Acres ROADS MOD 0.099 DRIVEWAYS MOD 0.099 Lement Flows To: _irface Interflow Groundwater Trapezoidal Pond 1, Trapezoidal Pond 1, Name Trapezoidal Pond 1 )ttom Length: 93ft. )ttom Width: 93ft. Depth : 0.27ft. volume at riser head : 0.0518ft. ifiltration On ifiltration rate : 0.33 Infiltration saftey factor : 0.33 - ,de slope 1: 0 To 1 Lde slope 2: 0 To 1 __de slope 3: 0 To 1 Side slope 4: 0 To 1 .scharge Structure .ser Height: 0.26 ft. Riser Diameter: 10000 in. cement Flows To: Pond Hydraulic Table 3tage(ft) Area(acr) Volume(acr-ft) Dschrg(c£s) Infilt(c£s) .000 0.199 0.000 0.000 0.000 u.003 0.199 0.001 0.000 0.022 0.006 0.199 0.001 0.000 0.022 .009 0.199 0.002 0.000 0.022 .012 0.199 0.002 0.000 0.022 0.015 0. 199 0.003 0.000 0.022 x.018 0.199 0.004 0.000 0. 022 .021 0.199 0.004 0.000 0.022 .024 0.199 0.005 0.000 0.022 0.027 0.199 0.005 0.000 0.022 ^.030 0.199 0.006 0.000 0.022 .033 0.199 0.007 0.000 0.022 .036 0.199 0.007 0.000 0.022 0.039 0.199 0.008 0.000 0.022 - .042 0.199 0.008 0.000 0.022 .045 0.199 0.009 0.000 0.022 ...048 0.199 0.010 0.000 0.022 0.051 0.199 0.010 0.000 0.022 .054 0.199 0.011 0.000 0.022 .057 0.199 0.011 0.000 0.022 u.060 0.199 0.012 0.000 0.022 0.063 0. 199 0.013 0.000 0.022 066 0.199 0.013 0.000 0.022 069 0.199 0.014 0.000 0.022 u.072 0.199 0.014 0.000 0.022 0.075 0.199 0.015 0.000 0.022 ,078 0.199 0.015 0.000 0.022 ,081 0.199 0.016 0.000 0.022 0.084 0.199 0.017 0.000 0.022 n .087 0.199 0.017 0.000 0.022 .090 0.199 0.018 0.000 0. 022 .093 0.199 0.018 0.000 0. 022 0.096 0.199 0.019 0.000 0.022 ^ .099 0.199 0.020 0.000 0.022 102 0.199 0.020 0.000 0.022 105 0.199 0.021 0.000 0. 022 0.108 0.199 0.021 0.000 0.022 - .111 0.199 0.022 0.000 0.022 114 0.199 0.023 0.000 0.022 .,.117 0.199 0.023 0.000 0.022 0.120 0.199 0.024 0.000 0. 022 123 0.199 0.024 0.000 0.022 126 0.199 0.025 0.000 0.022 u.129 0.199 0.026 0.000 0. 022 0.132 0.199 0.026 0.000 0. 022 135 0.199 0.027 0.000 0. 022 138 0.199 0.027 0.000 0. 022 u.141 0.199 0.028 0.000 0.022 0.144 0.199 0.029 0.000 0. 022 147 0.199 0.029 0.000 0.022 150 0.199 0.030 0.000 0.022 0.153 0. 199 0.030 0.000 0.022 n 156 0.199 0.031 0.000 0. 022 159 0.199 0.032 0.000 0. 022 162 0.199 0.032 0.000 0. 022 0.165 0.199 0.033 0.000 0. 022 • 168 0.199 0.033 0.000 0. 022 171 0.199 0.034 0.000 0. 022 174 0.199 0.035 0.000 0. 022 0.177 0.199 0.035 0.000 0. 022 180 0.199 0.036 0.000 0. 022 183 0.199 0.036 0.000 0. 022 .,.186 0.199 0.037 0.000 0. 022 0.189 0.199 0.038 0.000 0. 022 192 0.199 0.038 0.000 0. 022 " .201 0.199 0.040 0.000 0.022 .204 0.199 0.041 0.000 0.022 .,.207 0.199 0.041 0.000 0.022 0.210 0.199 0.042 0.000 0.022 .213 0.199 0.042 0.000 0.022 .216 0.199 0.043 0.000 0.022 u.219 0.199 0.043 0.000 0.022 0.222 0.199 0.044 0.000 0.022 .225 0.199 0.045 0.000 0.022 .228 0.199 0.045 0.000 0.022 u.231 0.199 0.046 0.000 0.022 0.234 0.199 0.046 0.000 0.022 .237 0.199 0.047 0.000 0.022 .240 0.199 0.048 0.000 0.022 0.243 0.199 0.048 0.000 0.022 x.246 0.199 0.049 0.000 0.022 .249 0.199 0.049 0.000 0.022 .252 0.199 0.050 0.000 0.022 0.255 0.199 0.051 0.000 0.022 ^.258 0.199 0.051 0.000 0.022 .261 0.199 0.052 0.257 0.022 .264 0.199 0.052 2.053 0.022 0.267 0.199 0.053 4.753 0.022 " .270 0.199 0.054 8.116 0.022 MITIGATED LAND USE ANALYSIS RESULTS .ow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) year .=-70.024295 year 0.03789 _J year 0.04529 25 year y0.052829 year 0.057313 )0 year y0.061002 Flow Frequency Return Periods for Mitigated. POC #1 ,turn Period Flow(cfs) year 0 5 year 0 11 year 0 i year 0 _J year 0 100 year 0 nearly Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 150 0.028 0.000 51 0.054 0.000 1952 0.060 0.000 1953 0.019 0.000 54 0.014 0.000 .55 0.021 0.000 1956 0.037 0.000 ' Q57 0.031 0.000 58 0.024 0.000 59 0.026 0.000 1960 0.021 0.000 "'61 0.037 0.000 62 0.022 0.000 -63 0.013 0.000 1964 0.017 0.000 65 0.021 0.000 ' 968 0.037 0.000 r��' )69 0.022 0.000 \ IL%) _370 0.022 0.000 1971 0.017 0.000 )72 0.016 0.000 3.73 0.045 0.000 1974 0.019 0.000 1975 0.021 0.000 )76 0.032 0.000 )77 0.020 0.000 1978 0.002 0.000 1979 0.017 0.000 )80 0.010 0.000 )81 0.029 0.000 1982 0.015 0.000 1983 0.029 0.000 )84 0.027 0.000 )85 0.017 0.000 1986 0.009 0.000 1987 0.046 0.000 )88 0.039 0.000 )89 0.014 0.000 1990 0.009 0.000 ' 191 0.063 0.000 392 0.055 0.000 _993 0.018 0.000 1994 0.020 0.000 )95 0.005 0.000 )96 0.029 0.000 1397 0.057 0.000 1998 0.052 0.000 )99 0.011 0.000 Ranked Yearly Peaks for Predeveloped and Mitigated. POC #1 ink Predeveloped Mitigated 0.0632 0.0000 2 0.0600 0.0000 1 0.0566 0.0000 0.0552 0.0000 0.0545 0.0000 6 0.0520 0.0000 0.0461 0.0000 0.0445 0.0000 0.0390 0.0000 10 0.0374 0.0000 0.0368 0.0000 ' 0.0368 0.0000 .3 0.0320 0.0000 14 0.0315 0.0000 i 0.0292 0.0000 i 0.0289 0.0000 1! 0.0289 0.0000 18 0.0282 0.0000 0.0265 0.0000 i 0.0259 0.0000 21 0.0238 0.0000 22 0.0218 0.0000 ! 0.0217 0.0000 0.0215 0.0000 25 0.0214 0.0000 ')ti 0.0214 0.0000 0.0209 0.0000 0.0209 0.0000 29 0.0203 0.0000 ^1 0.0197 0.0000 0.0194 0.0000 ... 0.0186 0.0000 33 0.0182 0.0000 0.0172 0.0000 7 0.0169 0.0000 3 0.0164 0.0000 J9 0.0159 0.0000 40 0.0155 0.0000 0.0153 0.0000 '. 0.0142 0.0000 43 0.0141 0.0000 44 0.0126 0.0000 i 0.0106 0.0000 i 0.0100 0.0000 47 0.0091 0.0000 48 0.0089 0.0000 ) 0.0051 0.0000 0.0020 0.0000 )C #1 ie Facility PASSED ie Facility PASSED. r.i.ow(CFS) Predev Dev Percentage Pass/Fail 0.0121 3776 0 0 Pass 0126 3491 0 0 Pass 0131 3247 0 0 Pass 0.0135 3037 0 0 Pass 0.0140 2832 0 0 Pass 0144 2635 0 0 Pass 0149 2453 0 0 Pass 0.0153 2274 0 0 Pass x .0158 2130 0 0 Pass .0163 2000 0 0 Pass .0167 1885 0 0 Pass 0.0172 1776 0 0 Pass " .0176 1678 0 0 Pass .0181 1585 0 0 Pass _ .0185 1491 0 0 Pass 0.0190 1397 0 0 Pass - .0194 1319 0 0 Pass .0199 1238 0 0 Pass ....0204 1187 0 0 Pass 0.0208 1114 0 0 Pass .0213 1056 0 0 Pass .0217 1004 0 0 Pass u.0222 954 0 0 Pass 0.0226 902 0 0 Pass .0231 861 0 0 Pass .0236 818 0 0 Pass 0.0240 775 0 0 Pass 0.0245 738 0 0 Pass .0249 710 0 0 Pass .0254 669 0 0 Pass 0.0258 643 0 0 Pass ^.0263 616 0 0 Pass .0267 586 0 0 Pass .0272 566 0 0 Pass 0.0277 533 0 0 Pass 0281 508 0 0 Pass .0286 474 0 0 Pass _ .0290 452 0 0 Pass 0.0295 432 0 0 Pass " .0299 418 0 0 Pass .0304 391 0 0 Pass .,.0309 372 0 0 Pass 0.0313 354 0 0 Pass .0318 340 0 0 Pass .0322 322 0 0 Pass u.0327 305 0 0 Pass 0.0331 282 0 0 Pass .0336 273 0 0 Pass .0350 232 0 0 Pass .0354 222 0 0 Pass ,.0359 211 0 0 Pass 0.0363 206 0 0 Pass .0368 197 0 0 Pass .0372 189 0 0 Pass u.0377 182 0 0 Pass 0.0382 174 0 0 Pass .0386 168 0 0 Pass .0391 159 0 0 Pass 0.0395 155 0 0 Pass x.0400 151 0 0 Pass .0404 145 0 0 Pass .0409 143 0 0 Pass 0.0413 135 0 0 Pass n.0418 127 0 0 Pass .0423 120 0 0 Pass .0427 113 0 0 Pass 0.0432 109 0 0 Pass ".0436 107 0 0 Pass .0441 96 0 0 Pass -0445 89 0 0 Pass 0.0450 83 0 0 Pass .0455 75 0 0 Pass .0459 72 0 0 Pass .,.0464 63 0 0 Pass 0.0468 61 0 0 Pass .0473 58 0 0 Pass .0477 52 0 0 Pass u.0482 49 0 0 Pass 0.0486 47 0 0 Pass .0491 43 0 0 Pass .0496 39 0 0 Pass 0.0500 34 0 0 Pass x.0505 31 0 0 Pass .0509 29 0 0 Pass .0514 26 0 0 Pass 0.0518 25 0 0 Pass n.0523 23 0 0 Pass .0528 21 0 0 Pass .0532 21 0 0 Pass 0.0537 20 0 0 Pass ".0541 18 0 0 Pass .0546 17 0 0 Pass ...0550 14 0 0 Pass 0.0555 13 0 0 Pass - .0559 12 0 0 Pass .0564 9 0 0 Pass ..0569 7 0 0 Pass 0.0573 7 0 0 Pass iter Quality BMP Flow and Volume for POC 1. i-line facility volume: : .,`_ -fee- i-line facility target flow: J cfs. Adjusted for 15 min: 0 cfs. ,, f-line facility target flow: 0 cfs. ijusted for 15 min: 0 cfs. Perind and Impind Changes Vo changes have been made. This program and accompanying documentation is provided 'as-is' without warranty of any kind. The entire risk regarding m performance and results of this program is assumed by the user. Clear Creek Solutions and the Washington State apartment of Ecology disclaims all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable for any damages whatsoever (including without limitation to damages for loss of iciness profits, loss of business information, business interruption, and the like) arising out of the use of, or Talbot Road Townhomes 2-11-11 80 LF-110"x 171" arch cmp Orf#1 =0.46 inch diameter Orf#2 =0.875 inch diameter @ 6 feet above invert 10" diameter Riser Performance Curve-Level II- match durations%2-2 thru 50 year events ijj Fle Vex hi* Dd12 -mvp kt.; x;11;,1,:4 Juni •5E0POC1Pei*ed Caftan 219.88 a id as _ F01o710251 0501 0801 - --- __ 311f9C1MIgaedOxv 0.0121 3716 2875 A 0.0126 3491 1919 F0.0131 3247 1309 `9 10.0135 3037 786 0 10,0140 2832 630 10144 2635 607 803 0149 2453 594 0 0.0153 2274 580 0.0158 7130 575 t ate _-_._-._--_--__ 0.0163 2000 569 0.0167 1885 558 0.0172 1776 552 0.0176 1678 547 10E4 10E•3 1E2 111-1 1 10 pp 0.0101 1585 538 0.0185 1191 530 Percent T1me Exceeding 0.0190 1397 523 0.0194 1319 513 0.0199 1238 501 Duatimr iPonFourq I W94.0* I Mph I Wanaductoi 0.0204 1187 495 0.0208 1114 485 0.0213 1056 474 �l 1P1.01111PDJLYEVAPW/ENSEN414ISE DuahnBare 0.0217 1004 465 33 2SEATACSEE WORD RLE EUETFCPREM4TADOCAFk aor IT17 Mir ii- :Lb 0.0222 954 458 OY151G1 Prdre.ln e1 or via,' .:,. ._.` 0.0226 902 435 71114$a10F0C1 S f0G19 0.0231 861 419 0.0236 818 910 lOD3V0�tIALLOUTLETS M4�ed i IOW 1STAGE M9igdtd 0.0240 175 401 1032141 A1100T1ETS Mid 0.0245 138 388 0.0299 710 378 9JDalmdtFbrl Stage)Parol Evv POC1 0.0254 669 368 0.0258 643 360 0.0263 616 346 0.0267 586 337 0.0272 566 324 A 0977 111 116 _ 2/11/2011 4:40 PM i aitiotcritet Dt013•Tabotionn,., ®- pa(a�reane 1 "'..; r 7;^.�a:` 's �' 4 r 7- '�]GM 44 Graphic showing peak flows predeveloped (501)flows and post developed mitigated outflow from detention tank(801) Graphic Shows Post Developed Inflow to Detention Tank (701)for conveyance sizing FP Ed Wm jd rt _1 - _D Irl J iD POLI Pedcvekced Fier Frequency I! 1DE 1 I Ul irrbwmPOci o 1oq 4YS1 0501 0701 0881 BQ POC1 M .:flay 2 Tear = 0.0243 0.1261 8.014!`1 A 5 Year = 0.0379 0.1579 0.0225 10 Year = 0.0453 0.1790 0.0296 0 IE 25 Year = 0.0528 0.205 t 0.0408,'j, 50 Year = 0.0573 0.2257 0.0509 I 190 Tear= 0.6610 0.2460 0.0626' 0 Yearly Peaks -,,�ddddeAAAAA6AaAAaAa 1949 0.0282 0.1315 0.0185' T�I SaCdaA,A,,,uEdahgew� A a 1958 0,0545 0.2200 0.0130' 0000000 1951 0.0600 0.1359 0.0465 . 000y„,A.,,, coo" 1952 0.0186 0.1028 0.0097 1953 0.0142 0.0983 0.0115: 0 0pppp00°° 1954 0.0209 0.1214 0.0121 1 fl 21 31 6150 60 10 80 90 99 1955 0.0368 0.1256 0.0122 o ���.rty 1956 0.0315 0.1217 0.0173 utautatre1957 0,0238 0.1459 0.0121:I 1958 0.0259 0.1273 0.0125 Daaba Poafaqsrq 141160 R1da04h Wej144°11 1959 0.0214 0.0953 0.0109 1.980 0.0374 0,1241 0.0400 if alwAs 1961 0.0217 0.1089 0.0129 7 1PN/6111PDIY EW6'WUE119ER+WISE Li 1962 0.0126 0.1061 0.0092 3 BEMACSEEWORDELUEFFlPERATODOCR41 1963 0.0171 0.1087 0.0120 :±''` 1964 0.0214 0.1238 0.0121 t�n,,at7i;'1u,G ? 1965 0.0159 0.1092 0.0205 21 N-;re.: '. 1030Val1AU.0UTETS1.09d c 1966 0.0164 0.1101 0.0113 I1D7IVa11ma* 1967 0.0368 0.1659 0.0124 1ln2Tai1f11DII11FTSacid 1f 1968 0.0218 0.1848 0.0114 1969 0.0215 0,1011 0.0110 Alakkeh JJ Exp PIICt 1970 0.0170 0.1107 0.0115 1971 0.0155 0.1062 0.8126 1972 0.0445 0.1660 0.0355 1973 0.0194 0.0983 0.0148 1974 0.0209 0,1176 0.0126_ 1a're 0 arm 0 1567 a 1111a 2111I2011 4:56PM t 1 � [010wietioen 1 441-143 1 IF]Paforma6eone _ P ' ° r� 436PM SECTION 5.3 DETENTION FACILITIES Riser Overflow The nomograph in Figure 5.3.4.H may be used to determine the head(in feet)above a riser of given diameter and for a given flow(usually the 100-year peak flow for developed conditions). ._ FIGURE 5.3.4.11 RISER INFLOW CURVES7 100 - — 1 72 54 48 H4420.00 //01, 36 33 30 000 27 r 0•0 24 r y o / 21 =IF cto u 18 10 15 N — u i a a /1",10111 �/ f /FI 12 — 011111 10 0.1 HEAD IN FEET(measured10 from crest of riser) Qwe4,=9.739 DHS Q. 10=3.782 D2H112 Q in cfs,D and H in feet Slope change occurs at weir-orifice transition 1/24/2005 2005 Surface Water Design Manual 5-48 1 �f _ I I LOCI ER- C Uits / it .s/4v ?171"lieor a-GRP 3'66 (-bite EoQ #S DiSr utharo) rlor Zoog 164Jrust 5 1 T i wlu. L 4 IjZ OV ZPG FiL? F,t440) 81 DS G, . -- „ ?rte_< ru W - gwh.tty srbtAi = ;5% of 2 Lig PeYeLateco Pet, 11-(4213 titer Aps, ICG,SGuM PPS h i i ( 2q/ $lvawi S I P, 4,-/o3) W Q rizoi c-rGTi 15/hi704,, .57#F1- S6tl-77K. 1.0 sutr- FA4n2 Av-PciztvoOD FQoM sfe 57h-7417Ic.S. - pe1tvio9i TI'- ut'u0G$pE = 0.3 fq<}o - )/4 ?..yooj -* 04;1 a(- -Fvow, ?rtuvrpur Fou rxo,nss I!L DEv : 0,301 cps 10oy0-pev = 0.9osGF3. toei) ST oncy= x 0.10( = 0./o5" cfs I I i I 1 /f-, Talbot Road-Water Quality Storm Run using KCRTS with 15 minute Time Steps Note: predev conditions using 1 hour time steps also included for reference only KCRTS Program...File Directory: C:\KC_SW DM\KC_DATA\ [C] CREATE a new Time Series ST 0.00 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 0.32 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.63 0.00 0.000000 Impervious dev.tsf T 1.00000 F [C] CREATE a new Time Series ST 0.95 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 0.00 0.00 0.000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.00 0.00 0.000000 Impervious predev 1 hour timesteps.tsf T 1.00000 T [T] Enter the Analysis TOOLS Module [P] Compute PEAKS and Flow Frequencies predev 1 hour timesteps.tsf predev 1 hour timestep.pks [P] Compute PEAKS and Flow Frequencies dev.tsf dev 15 min time step.pks [R] RETURN to Previous Menu [X] eXit KCRTS Program n '?' . ..v... jda King County Runoff Time Series Progrea Yasies 0.00 lll files nil be read/nittee in the Forking Directory Directory:C:\kc_swdm\aetput F KCBTS Command CREATE a new Time Series • Pradectioo of Moil Tine Series Project!oration: Sea-Tac Ccepeting Series dev.tat liegianai Scale Factor 1.00 Data Type:Reduced Creating 15-emote Time Series File loading Time Series File:C:1C SSDNC DATA\5RGl5R.rnf 8 gill Grass 0.32 acres Scaling yr: 8 Loading Tie Series File:C:\KC_SFDNC DATA\STEI15B.rnt 8 Inpervious 0.63 acres Adding Yr: 8 Total Area: 0.9S acres !Peek Discharge: 0.905 CFS at 6:30 an Jan 9 is Year 8 Storing Time Series File:dev tsf B Time Series Capital KITTS Comnaad CRATE a nes Time Series Productis of Runoff Time Series Project location•Sea-Tac Gauping Series predev 1 hoar tinesteps.tot Regional Scale Factor 1.00 Data Type•Reduced Creating bhp Tine Series File Loading Time Series FoIe:C.\BC_SRDINC DATIv"ITF60F.rnf 8 ill Forest 0.95 acres Scaling Fr: 8 Total Area: 0.95 acres Discharge: 0.077 CFS at 9:00 on Jan 9 in Year 8 Storing Tie Series File:predev 1 hour tinesteps.tsf 8 1, • E Tie Series Comooted . Kam Cammand Enter the Analysis TOOLS fladele Analysis Tools Conmand k�a•rtnofaha,�_Carast et_Htat. ®amcaDaxe[q.., jKc lmsf2•ujco,,, pF"+ ° 1 � 6!4,33P1 Jia Analysis lam Couand agate PEAKS and Flo,Frequencies loading Stage/Discharge c,rve.predev 1 hour tiresteps.tsf Flo,Frequency Analysis Tine Series File:predev 1 hon tiieste{s.tsf Project Irratuon:Sea-Tac Frequencies&Peaks saved to File:predev 1 hoar tirestep.pks Analysis Tools Conant' Canpute PEALS and Flo,Fos/uncles loading Tine Series file:dev.tsf 8 Flo,Frequency Analysis Tine Series File:dev,tsf Project location:Sea-lac Frequencies&Peaks saved to File.dev 15 un tine step.pks ; "".77- w. ._.+.i'}«.- ..b. ;: .7_*.,.: z:: i,®��'`-��;,, jTire Series File:prekv 1 hour tiiesteps.tsf Project locatinSeea-Tec -Annual Peak Flow Rates- -Flo!Frequency Analysis- Flow nalysis-Flo,Rate Rank Tire of Peak --Peaks-- Rank Return Pleb (CFS) (CFS) Period 0.060 2 2/09/01 18:00 0.077 1 100.00 0.990 0.016 7 1/06/02 3:00 0.060 2 25.00 0.960 0.044 4 2/28/03 3:00 0.046 3 10.00 0.900 0.002 8 3/24/04 20:00 0.044 4 5.00 0.800 0.027 6 1/05/05 8:00 0.039 5 3.00 0.667 0.046 3 1/18/06 20:00 0.027 6 2.00 0 600 0.039 5 11/24/06 4:00 0.016 7 1.30 0.231 0.077 1 1/09/08 9:00 0.002 8 1.10 0.091 Corpated Peaks 0.071 50.00 0.980 Flo,Frequency Analysis Tine Series Fil:45 Project lccation:Eea-ac -Annual Peak Flu Rates- -Flow Frequency Analysis- Fla Rate Rank Tine of Peak --Peaks-- Rank Return Prob (aS) (CFS) Period 'Obyt 0.301 6 8/27/01 18:00 0 905 1 100.00 0.990 0.212 8 1/05/02 15:00 (lb 2 25.00 0.960 4-- 15'1/L PTV, OAQ..Lvktt,C4Lc� 0.638 2 12/08/02 17:15 0.4 3 10.00 0.900 0.242 1 8/23/04 14:30 0.357 4 5.00 0.800 0.357 4 11/17/04 5:00 0.357 5 3.00 0.667 0.357 5 10/27/05 1045 0.301 6 2.00 0.500 2yti 1af,4t 0.419 3 10/25/06 22.45 0.242 1 1.30 0.231 ,1 0.905 1 1/09/08 6.30 0.212 8 1.10 0.091 Carpeted Peaks 0.816 50.00 0.980 u k Moamf 1002,,, ,KC 1➢1512 i.,. , }3 Q'.; r �' 4: FK Cw stud l E W<aCW1 l Oaonefl 14L„ I .3,p4 Flow Frequency Analysis Time Series File:predev 1 hour timesteps.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Frequency Analysis Flow Rate Rank Time of Peak -- Peaks-- Rank Return Prob (CFS) (CFS) Period 0.060 2 2/09/01 18:00 0.077 1 100.00 0.990 0.016 7 1/06/02 3:00 0.060 2 25.00 0.960 0.044 4 2/28/03 3:00 0.046 3 10.00 0.900 0.002 8 3/24/04 20:00 0.044 4 5.00 0.800 0.027 6 1/05/05 8:00 0.039 5 3.00 0.667 0.046 3 1/18/06 20:00 0.027 6 2.00 0.500 0.039 5 11/24/06 4:00 0.016 7 1.30 0.231 0.077 1 1/09/08 9:00 0.002 8 1.10 0.091 Computed Peaks 0.071 50.00 0.980 Flow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Frequency Analysis Flow Rate Rank Time of Peak -- Peaks-- Rank Return Prob (CFS) (CFS) Period 0.301 6 8/27/01 18:00 0.905 1 100.00 0.990 0.212 8 1/05/02 15:00 0.638 2 25.00 0.960 0.638 2 12/08/02 17:15 0.419 3 10.00 0.900 0.242 7 8/23/04 14:30 0.357 4 5.00 0.800 0.357 4 11/17/04 5:00 0.357 5 3.00 0.667 0.357 5 10/27/05 10:45 0.301 6 2.00 0.500 0.419 3 10/25/06 22:45 0.242 7 1.30 0.231 0.905 1 1/09/08 6:30 0.212 8 1.10 0.091 Computed Peaks 0.816 50.00 0.980 Av%1\/TCAtJ® Size and Cost Estimate STORMWATER SOLUTIONS INC. Prepared by Kathryn Thomason on May 19, 2011 Talbot Road Townhomes - Stormwater Treatment System Renton, WA Information provided: • Structure ID = Basic Enhanced • Total Area (acre) = 0.95 0.95 • Percent Impervious = 66 66 • Water Quality Flow, WQF (cfs) = 0.105 0.105 • Peak Flow, Q100 (cfs) = 0.905 0.905 • Cartridge Height(inches) = 18" 18" • Media Type = ZPG CSF • Cartridge Flow Rate (gpm) = 7.5 15 Assumptions: • Drop required from inlet to outlet = 2.3' minimum • Presiding agency = City of Renton Size and cost estimates: The StormFilter is a flow-based system, and therefore, is sized by calculating the water quality flow rate associated with the design storm. The water quality flow rate was calculated using 35% of the developed 2-year flow rate from KCRTS. Water Structure Quality Approximate No. of Estimated ID Depth Cartridges System Size Media Cost Flow Type Basic 0.105 6' 7 72" Manhole ZPG $27,200 Enhanced 0.105 6' 4 60" Manhole CSF $20,200 The estimated costs are for complete systems delivered to the job site. This estimate assumes that the vault is 6 feet deep. The final system cost will depend on the actual depth of the units and whether extras are specified. The contractor is responsible for setting the StormFilter systems and all external plumbing. Typically the precast StormFilters have internal bypass capacities of 1.8 cfs. If the peak discharge off the site is expected to exceed this rate, we recommend placing a high-flow bypass upstream of the StormFilter system. CONTECH Stormwater Solutions could provide our high-flow bypass, the StormGate, which provides a combination weir-orifice control structure to limit the flow to the StormFilter. The estimated cost of this structure is $4.000. The final cost would depend on the actual depth and size of the unit. ©2006 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-P027 `r!l►f.r•: wA!li SFORMWATER___-, SizingEstimate J7OLunONS INC. Provided by Kathryn Thomason on May 19, 2011 Talbot Road Townhomes Renton, WA Site information: Structure ID Area % Impervious Water Quality Peak Flow (acres) Flow(cfs) (cfs) Presettling 0.95 ac 66% 0.105 0.905 CDS System Sizing: The CDS Stormwater Treatment System is a high-performance hydrodynamic separator. Using patented continuous deflective separation technology, the CDS system screens, separates and traps debris, sediment, and oil and grease from stormwater runoff.The indirect screening capability of the system allows for 100% removal of floatables and neutrally buoyant material without blinding. Flow and screening controls physically separate captured solids, preventing re-suspension and release of previously trapped pollutants The CDS model was selected based on WADOE GULD approval using a 2400 micron screen. Water Quality CDS Treatment System Recommended CDS Model Flow(cfs) Flow(cfs) Estimated Price Presettling CDS20154 0.105 0.7 $6,900 Maintenance: Like any stormwater best management practice, the CDS system requires regular inspection and maintenance to ensure optimal performance. Maintenance frequency will be driven by site conditions. Quarterly visual inspections are recommended, at which time the accumulation of pollutants can be determined. On average, the CDS system requires annual removal of accumulated pollutants. ©2006 CONTECH Stormwater Solutions 11835 NE Glenn Wading Drive Portland,OR Page 1 of 1 contechstormwater.com Toll-free:800.548.4667 Fax:800.561.1271 V. CONVEYANCE SYSTEMS ANALYSIS AND DESIGN Since project is less than 1 acre,then conservatively, Using the Rational Method as a quick check: A=0.95 acre Area Impery=66%=0.63 acre, Area Pervious=0.95-0.63=.32 Cave=(0.63 ac x 0.9)+(0.32 ac x 0.2)=0.631 (Cn lawn/landscape=0.2) I25=2.5" Q=CIA=0.631 x 0.95 x2.5=1.49 cfs A 12" smooth bore(n=0.012) @ 2% slope yields 5.5cfs 5.5 cfs>1.49 cfs : o.k. • full flow velocity= 8.5fps which exceeds 3fps : o.k. Note: 1.49 CFS compares conservatively with WWHM3 model results indicating 0.257 CFS as peak 25 year inflow to detention tank. 1.49 CFS compares conservatively with KCRTS model results indicating 0.638 CFS as Peak 25 year runoff from developed conditions using 15 minute time steps(See Water Quality Design Section for reference model output data). A backwater analysis has been prepared using Hydraflow Software by Intellisolve for the 25 year conveyance analysis using 0.638 CFS as the inflow on all upstream structures, which is a very conservative approach, but which demonstrates the adequate conveyance capacity. Tailwater elevations were included to reflect the dispersal trench (el 138.0) and the 25 year water surface elevation in the detention tank(145.82). Hydraflgw Plan View - 1 4 E 28 q, -T Project file: 2011-06-04.stm No. Lines: 8 06-02-2011 Hydraflow Storm Sewers 2003 (—"If)) v��� 1 SE...vr r Jf11C Prod. rile: 201 i-uo-04.stm E Iev (ft) Line 1 - CD-116 ko M H#1 r ,,anhole 151.00 151.00 147.00 147.00 143.00 143.00 133.00 139.00 �1 69 135.00 - 135.00 131.00 131.00 0 5 10 15 20 25 30 35 40 45 50 55 60 85 70 75 80 Reach (ft) Hydraflow Storm Sewers 2003 v a 01 Slaw er . . af..air Prod. rne: 2011-uc5-04.srm C05 Hi 7D c-0"41 Elev. (ft) 158.00 155.00 152.00 Ln. 7 Ln. 8 Ln:6 — — (in) 8 (in) -1214.0 ---------------149.00 ----� —111111r- 146.00 _ — 143.00 0 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2003 .tO1Ili Sewer . . Oflle Prof. rile: 2011-ub-04.stm Elev. (ft) 155.00 - 152.00 -In:2-Ln:.3 12(m)12(in) (m} 149.00 146.00 143.00 — - 140.00 0 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2003 Storm Sewer Summary Report Page 1 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL , Minor Dns No. rate size length EL Dn EL Up slope down up loss line (cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) No. 1 CB-1116 to MH#1 0.64 12 c 58.0 135.50 138.22 4.690 138.00 138.56 0.12 End 2 MH#2 to ZPG 1.28 12 c 8.0 142.60 142.70 1.250 145.82* 145.83* 0.04 End 3 ZPG to CDS 1.28 12 c 2.0 145.00 145.03 1.500 145.87 145.87 0.05 2 4 CDS to CB#4 0.64 12 c 36.0 145.03 146.21 3.278 145.92 146.55 0.12 3 5 C8#4to CB#5 0.64 8 c 18.0 146.21 146.30 0.500 146.66 146.74 0.11 4 6 CDS to CB#3 0.64 12 c 11.0 145.03 145.20 1.545 145.92 145.92 0.02 3 7 CB#3 to CB#2 0.64 12 c 56.0 145.20 146.56 2.429 145.94 146.90 0.12 6 8 C13#2 to CB#1 0.64 8 c 22.0 146.56 147.00 2.000 147.01 147.38 0.15 7 Project File: 2011-06-04.stm Number of lines: 8 Run Date: 06-02-2011 NOTES: c=circular; e=elliptical; b=box; Return period= 25 Yrs.; *Indicates surcharge condition. Hydraflow Storm Sewers 2003 ..•tori„ Jewer Muicsuoll Page 1 Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Gmd/Rim Elev Line ID coeff (I) flow full Line To Incr Total incr Total Inlet Syst Size Slope Up Dn Up Dn Up Dn Une (ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft) 1 End 58.0 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.64 7.71 1.77 12 4.69 138.22 135.50 138.56 138.00 150.10 138.00 CB-#6 to MH#1 2 End 8.0 0.00 0.00 0.00 0.00 0.00 0.0 1.6 0.0 1.28 3.98 1.63 12 1.25 142.70 142.60 145.83 145.82 149.51 149.51 MH#2 to ZPG 3 2 2.0 0.00 0.00 0.00 0.00 0.00 0.0 1.6 0.0 1.28 4.36 1.79 12 1.50 145.03 145.00 145.87 145.87 149.45 149.51 ZPG to CDS 4 3 36.0 0.00 0.00 0.00 0.00 0.00 0.0 0.2 0.0 0.64 6.45 1.80 12 3.28 146.21 145.03 146.55 145.92 149.30 149.45 CDS to CB#4 5 4 18.0 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.64 0.85 2.58 8 0.50 146.30 146.21 146.74 146.66 149.30 149.30 CB#4 to CB#5 6 3 11.0 0.00 0.00 0.00 0.00 0.00 0.0 1.3 0.0 0.64 4.43 0.96 12 1.55 145.20 145.03 145.92 145.92 149.50 149.45 CDS to CB#3 7 6 56.0 0.00 0.00 0.00 0.00 0.00 0.0 0.2 0.0 0.64 5.55 1.88 12 2.43 146.56 145.20 146.90 145.94 150.35 149.50 CB#3 to CB#2 8 7 22.0 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.64 1.71 2.83 8 2.00 147.00 146.56 147.38 147.01 150.35 150.35 CB#2 to CB#1 Project File: 2011-06-04.stm Number of lines:8 Run Date: 06-02-2011 NOTES: Intensity= 102.61 /(Inlet time+ 16.50)^0.82; Return period= 25 Yrs. Hydraflow Storm Sewers 20031 VI. BASIN AND COMMUNITY PLANNING AREAS (NA) VII. OTHER PERMITS (N.A.) VII. EROSION/SEDIMENTATION CONTROL DESIGN Esc Plan Analysis and Design Erosion Control BMP's shall consist of a construction limits,rock construction entrance,silt fencing and catch basin protection for downstream facilities. A full ESC design is provided as Sheet C3 of the construction documents. Construction Phasing — In order to prevent erosion and trap sediments within the project site, the following BMPs will be used approximately as shown on the ESC plan and in the order described below: • Clearing limits will be marked by fencing or other means on the ground. • The catch basin insert shown on the plans shall be installed. •At the driveway area the rocked construction entrance shall be installed. •Runoff will not be allowed to concentrate and no water will be allowed to point discharge onto the slopes. • Silt fencing will be placed along slope contours at the down-slope limit of clearing. • Temporary cover measures will be used as required per the ESC notes for wet-season construction. • Sediment trap and ditch conveyance are included for the project. •Construction Schedule—The project construction will initiate in the summer of 2011 and will take approximately three to 6 months to complete. SWPPS (Surface Water Pollution Prevention Plan) Project Description- The Proposed Development consists of redevelopment an existing parcel with an existing home into a total of 18 townhome units. The site is located at 4701 Talbot Road South, in Renton,Washington. The site consists of a total of 0.95 acres and is currently developed as a single-family residence,concrete and gravel parking area and landscaped yard. The proposed development will create 27,533 s.f. of new impervious surface. �o( The Geotechnical Engineering Studies by Pioneer Engineering, Inc. dated 7/3/07 and 12/3/10 indicates about 2 to 3 feet of fill over much of the site underlain by till soils with very light groundwater evidence in some exploration holes at about 3 feet of depth. There are no indications of closed depressions on the property. The proposed residential development requires no Frontage Road Improvements for Talbot Road South. The anticipated volumes of grading cut and fill that are proposed are as follows: Cut< 800 cy Fill<3,500 cy Erosion Specialist. The project civil engineer may be contacted in the event that construction observation is required. Contact information is as follows: Civil Engineer: Hagenson Consultants, LLC 6484-48`"Ave SW Seattle, WA 98136 Contact: Hal Hagenson, P.E. Ph: 206-938-6168 Email: H.Hagenson@Comcast.net Existing Site Conditions:The property has an existing single-family residence,concrete&graveled drive area with landscaped yard. Existing Grades slope generally towards the west. Site slopes vary between 2 and 10 percent. There are no indications of closed depressions on the property. Adjacent Areas: There are no immediate adjacent areas, including streams, lakes, wetlands, residential areas and roads that might be affected by the construction project. Drainage from the site Sheet flows westerly towards the adjacent developed multi-family parcel. Critical Areas- There are no critical areas in the site vicinity that would be impacted by the development. Soil: The Geotechnical Engineering Studies by Pioneer Engineering, Inc. dated 7/3/07 and 12/3/10 indicates about 2 to 3 feet of fill over much of the site underlain by till soils with very light groundwater evidence in some exploration holes at about 3 feet of depth. Site soils are classified in SCS mapping as Alderwood gravelly sandy loam (AgC), 6 to 15% slopes, hydrologic class C,till soils. Alderwood series have slow permeability; runoff potential is slow to medium and a moderate to server erosion hazard. Potential Erosion Problem areas: The site is slopes moderately with alderwood soils which have moderate to severe erosion hazard. Twelve Elements— Refer to the attached erosion and sedimentation control plan for each BMP and its location. Construction Phasing: In order to prevent erosion and trap sediments within the project site, the following BMPs will be used approximately as shown on the ESC plan and in the order described below: • Clearing limits will be marked by fencing or other means on the ground. •The catch basin insert shown on the plans shall be installed. • At the driveway area the rocked construction entrance shall be installed. •Runoff will not be allowed to concentrate and no water will be allowed to point discharge onto the slopes. • Silt fencing will be placed along slope contours at the down-slope limit of clearing. • Temporary cover measures will be used as required per the ESC notes for wet-season construction. • Sediment retention and flow control will be accomplished in the onsite detention tank, which will be cleaned before final acceptance. •Construction Schedule—The project construction will initiate in the summer of 2011 and will take approximately three to 6 months to complete. Financial Ownership Responsibilities: Bond information is provided in the TIR. Engineering Calculations: There are no required calculations. IX. BOND QUANTITIES WORK SHEET,RETENTION/DETENTION FACILITY SUMMARY SHEET AND SKETCH,AND DECLARATION OF COVENANT } g Completed by: BMP Implementation itle: 1.1 s r; Date: .,`j 1 Develop a plan for implementing each BMP. Describe the steps necessary to implement the BMP (i.e., any construction or design),the schedule for completing those steps(list dates),and the • - •n s res.. sible for im•lementation. Scheduled Milestone and Person ,: BMPs Description of Action(s) Completion Date(s) r Responsible for Required for rL.,.._ 1722lementation Action Good 1. .._ �.... a P Housekeeping in ,' i �; b t P i7 Preventive 1. C Maintenance 2 t. Ili .4 „ j 3. 4 r Spills 1, N Prevention �® I jand 2. E Emergency k I Cleanup L h k 3. 1 r. Inspections 1. i 2. 1 ,x 3 2005 Surface Water Design Manual (CSWPP =ones) 1/1/2005 Page 1 JQC ID , I Tre T RIM = pod.1 , RIM = 138.0 OVERFLOW EL = 146.88 IE = 135.5 IE OUT = 138.22 COPPER RIDGE APARTMENTS �C KC PARCEL NO. 3123059041 j FENCE CORN. IS SITE / N15'22'W 4.34' 41,361 ±sq.ft. acres / � N 162650.65 E = 1298948.43 ( I r / 6' WQOP BOAR1� �EhaCE N89'O1'001Y 247.99' i1, T-23N, R-5E. W.M. 3 ' CI .... _ 6 .t f 58 _ '_ . L i 1.-.1 I- / I ,,°' 30' OF 15% SLOPE - I o 0 -- — — 1 PER STD DISPERSAL ' -- PLAN 224 I~I a = 1 1 • / Z.J f nl I I CT7ll�liif � — 5� .- e x .30.—,. - ' . POROUS ONC RIM. '150.35 ., 1 �ol i - • PVMNTI 1 IE. OUT.= 147.Q. .. : • 1t4477 RIDGE APARTMENTS N litt (PCP)I _ (PC ) - ` ;EL NO. 3123059153 'S '� + r� ., 00 .I 11+00 a I I 12+00 � INT STA-10+70:q -. 1 a M if---1A-13110' 00 W i 1_ 2 TAL.8OT LANE i N N 4::/ STA 1183.33 H.H ' N® `a�: / S MH 2 ca_ III - SAN Co z • i..06..'_.`' �. .�wC v S6LF-12 ®2. e(PCP) (PCP) Q f i f: 133.11-\ ...di - - Lij�m I / F __ c`i N -- 8LF 12`'®1 2X �i P 1 -1).51,:,,,, �, l ` _ I^ --- STM` ' W i s cB,` - TYPE I z rzi ZPG H 6'0 .�' ',TYPE E 1 r RIM 1` 5 0 /- I /. cv a l . •,Rlly( 1" 9.50 - IE a^ 14 6 ' _ _ I- Z )-.I f i - 1- RIM 149.36 IE •= 15.20 - W z M IE 145.00 IN 7,,,,,- ' CDS MH/432°0®W/LO KIN Lam •< 1.1.1 0 14 .7 OUT 1.S6 RIM = 145.45 f O � 0 d 2LF-1 m 01.5% 00 z ' IE = 145 03 a cr Q / ` M w (11 11R ill `�\ '-�1-='J I 181E-8-0 0.• ~pw / E. 1/2, NW 1/4 J CO W / F' I. R-5E, W.M. 3 w -- 1 inch = 30 ft. 3 w / 41 APARTMENTSX — 3123059153 W p STM CB#5 N88'58'52'W 249.36' � FENCE CORM. IS TYPE 1 ' I 546'16'W 1.35' RIM = 149.3 /� I G STM CB#4 IE = 146.3 /� f TYPE I 4,1 1'. RIM = 149.3 1E OUT = 146.21 1 1 ;I I, COPPER RIDGE APARTMENTS �J KC PARCEL NO. 3123059153 et Site Improvement Bond Quantity Worksheet Original bond computations prepared by: Name: Talbot Road Townhomes Date: 3-Jun-11 PE Registration Number: 21823 Tel.#: 206-938-6168 Firm Name: Hagenson Consultants, LLC Address: 6484-48th Ave SW, Seattle, WA Project No: LUA 08-017 ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND* PUBLIC ROAD&DRAINAGE AMOUNT BOND*AMOUNT MAINTENANCE/DEFECT BOND* REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESC) (A) $ 5,776.7 TEMPORARY OCCUPANCY*** Existing Right-of-Way Improvements (B) $ 1,544.0 Future Public Road Improvements& Drainage Facilities (C) $ - Private Improvements (D) $ 251,310.1 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond*/** (A+B) $ 7,320.7 (First$7,500 of bond*shall be cash.) Performance Bond*Amount (A+B+C+D) = TOTAL (T) $ 258,630.8 T x 0.30 $ 77,589.2 OR Minimum bond*amount is$1000. Reduced Performance Bond*Total*** (T-E) $ 258,630.8 Use larger of Tx30%or(T-E) (B+C)x Maintenance/Defect Bond*Total 0.25= $ 386.0 NAME OF PERSON PREPARING BOND*REDUCTION: Date: *NOTE: The word"bond"as used in this document means any financial guarantee acceptable to King County. **NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition,corrective work,both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example,if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. ***NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. SURETY BOND RIDER NOTE: If a bond rider is used, minimum additional performance bond shall be $ 251,310.1 (C+D)-E REQUIRED BOND*AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 Site Improvement Bond Quantity Worksheet Unit #of Reference# Price Unit Quantity Applications Cost EROSION/SEDIMENT CONTROL Backfill & compaction-embankment $ 5.62 CY Check dams, 4" minus rock SWDM 5.4.6.3 $ 67.51 Each Crushed surfacing 1 1/4" minus WSDOT 9-03.9(3) $ 85.45 CY Ditching $ 8.08 CY Excavation-bulk $ 1.50 CY Fence, silt SWDM 5.4.3.1 $ 1.38 LF 663 1 915 Fence, Temporary(NGPE) $ 1.38 LF Hydroseeding SWDM 5.4.2.4 $ 0.59 SY Jute Mesh SWDM 5.4.2.2 $ 1.45 SY Mulch, by hand, straw, 3"deep SWDM 5.4.2.1 $ 2.01 SY Mulch, by machine, straw, 2" deep SWDM 5.4.2.1 $ 0.53 SY Piping, temporary, CPP, 6" $ 10.70 LF Piping, temporary, CPP, 8" $ 16.10 LF Piping, temporary, CPP, 12" $ 20.70 LF Plastic covering, 6mm thick, sandbagged SWDM 5.4.2.3 $ 2.30 SY Rip Rap, machine placed; slopes WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance, 50'x15'x1' SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929 Sediment pond riser assembly SWDM 5.4.5.2 $ 1,949.38 Each Sediment trap, 5' high berm SWDM 5.4.5.1 $ 17.91 LF Sed.trap,5'high,riprapped spillway berm section SWDM 5.4.5.1 $ 68.54 LF Seeding, by hand SWDM 5.4.2.4 $ 0.51 SY Sodding, 1" deep, level ground SWDM 5.4.2.5 $ 6.03 SY Sodding, 1" deep, sloped ground SWDM 5.4.2.5 $ 7.45 SY TESC Supervisor $ 74.75 HR _ Water truck, dust control SWDM 5.4.7 $ 97.75 HR WRITE-IN-ITEMS **** (see page 91 Catch Basin Protection $ 100.00 Each 6 1 600 ESC SUBTOTAL: $ 4,443.62 30% CONTINGENCY& MOBILIZATION: $ 1,333.09 ESC TOTAL: $ 5,776.71 COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 04/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 sire Improvement Bona Quantity vVorKshee Existing Future Public Private Quantity Completed Right-of-Way Road Improvements Improvements (Bond Reduction)* &Drainage Facilities Quant. Unit Price _ Unit Quant. Cost Quant. Cost Quant. _ Cost Complete Cost GENERAL`ITEMS Backfill&Compaction-embankment $ 5.62 CY _ 3500 19,670.00 Backfill&Compaction-trench $ 8.53 CY Clear/Remove Brush,by hand $ 0.36 SY Clearing/Grubbing/Tree Removal $ 8,876.16 Acre Excavation-bulk $ 1.50 CY 500 750.00 Excavation-Trench $ 4.06 CY Fencing,cedar,6'high $ 18.55 LF Fencing,chain link,vinyl coated, 6'high $ 13.44 LF Fencing,chain link,gate,vinyl coated, 20' $ 1,271.81 Each Fencing,split rail,3'high $ 12.12 LF Fill&compact-common barrow $ 22.57 CY Fill&compact-gravel base $ 25.48 CY Fill&compact-screened topsoil $ 37.85 CY Gabion, 12"deep,stone filled mesh $ 54.31 SY Gabion, 18"deep,stone filled mesh $ 74.85 SY Gabion,36"deep,stone filled mesh $ 132.48 SY Grading,fine,by hand $ 2.02 SY Grading,fine,with grader $ 0.95 SY 2000 1,900.00 Monuments,3'long $ 135.13 Each Sensitive Areas Sign $ 2.88 Each Sodding,1"deep,sloped ground $ 7.46 SY 500 3,730.00 Surveying,line&grade $ 788.26 Day 3 2,364.78 Surveying,lot location/lines $ 1,556.64 Acre Traffic control crew(2 flaggers) $ 85.18 HR 16 1,362.88 Trail,4"chipped wood $ 7.59 SY Trail,4"crushed cinder $ 8.33 SY Trail,4"top course $ 8.19 SY Wall,retaining,concrete $ 44.16 SF 80 3,532.80 Wall,rockery $ 9.49 SF 140 1,328.60 Page 3 of 9 SUBTOTAL 34,639.06 Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 mite Improvement Boma Quantity vVorKsheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost ROAD IMPROVEMENT - AC Grinding,4'wide machine< 1000sy $ 23.00 SY AC Grinding,4'wide machine 1000-2000sy $ 5.75 SY AC Grinding,4'wide machine>2000sy $ 1.38 SY AC Removal/Disposal/Repair $ 41.14 SY Barricade,type I $ 30.03 LF Barricade,type III(Permanent) $ 45.05 LF Curb&Gutter,rolled $ 13.27 LF Curb&Gutter,vertical $ 9.69 LF 602 5,833.38 Curb and Gutter,demolition and disposal $ 13.58 LF 36 488.88 Curb,extruded asphalt $ 2.44 LF _ Curb,extruded concrete $ 2.56 LF Sawcut,asphalt,3"depth $ 1.85 LF Sawcut,concrete,per 1"depth $ 1.69 LF Sealant,asphalt $ 0.99 LF Shoulder,AC, (see AC road unit price) $ - _ SY Shoulder,gravel,4"thick $ 7.53 SY Sidewalk,4"thick $ 30.52 SY Sidewalk,4"thick,demolition and disposal $ 27.73 SY Sidewalk,5"thick $ 34.94 SY 20 698.80 Sidewalk,5"thick,demolition and disposal $ 34.65 SY Sign,handicap $ 85.28 Each Striping,per stall $ 5.82 Each Striping,thermoplastic,(for crosswalk) $ 2.38 SF Striping,4"reflectorized line $ 0.25 LF Page 4 of 9 SUBTOTAL 1,187.68 5,833.38 Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 bite Improvement Bona Quantity vVorksheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost --- -- - --- - ROAD SURFACING (4"Rock=2.5 base& 1.5"top course) For' u.5" ;d=5'base& 1.5"top course) For KCRS'93,(additional 2.5"base)add: $ 3.60 SY AC Overlay, 1.5"AC $ 7.39 SY AC Overlay,2"AC $ 8.75 SY AC Road,2",4"rock,First 2500 SY $ 17.24 SY AC Road,2",4"rock,Qty.over 2500SY $ 13.36 SY AC Road,3",4"rock, First 2500 SY $ 19.69 SY AC Road,3",4"rock,Qty.over 2500 SY $ 15.81 SY AC Road,5", First 2500 SY $ 14.57 SY AC Road,5",Qty. Over 2500 SY $ 13.94 SY AC Road,6", First 2500 SY $ 16.76 SY AC Road,6",Qty.Over 2500 SY $ 16.12 SY Asphalt Treated Base,4"thick $ 9.21 SY Gravel Road,4"rock, First 2500 SY $ 11.41 SY Gravel Road,4"rock,Qty.over 2500 SY $ 7.53 SY PCC Road,5",no base,over 2500 SY $ 21.51 SY PCC Road, 6",no base,over 2500 SY $ 21.87 SY Thickened Edge $ 6.89 LF Page 5 of 9 SUBTOTAL Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 site Improvement Bona Quantity vIorresheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost DRAINAGE (CPP=Corrugated Plastic Pip , i Access Road, R/D $ 16.74 SY Bollards-fixed $ 240.74 Each _-.---------------- Bollards-removable $ 452.34 Each '(CBs include frame and lid) CB Type I $ 1,257.64 Each 6 7,545.84 CB Type IL $ 1,433.59 Each CB Type II,48"diameter $ 2,033.57 Each 1 2,033.57 _ for additional depth over 4' $ 436.52 FT 7.3 3,186.60 CB Type II,54"diameter $ 2,192.54 Each 1 2,192.54 for additional depth over 4' $ 486.53 FT 7.5 3,648.98 CB Type II,60"diameter $ 2,351.52 Each for additional depth over 4' $ 536.54 FT CB Type II,72"diameter $ 3,212.64 Each for additional depth over 4' $ 692.21 FT Through-curb Inlet Framework(Add) $ 366.09 Each Cleanout, PVC,4" $ 130.55 Each Cleanout, PVC,6" $ 174.90 Each Cleanout,PVC,8" $ 224.19 Each 8 1,793.52 Culvert, PVC,4" $ 8.64 LF Culvert, PVC,6" $ 12.60 LF Culvert, PVC, 8" $ 13.33 LF 329 4,385.57 Culvert, PVC, 12" $ 21.77 LF Culvert,CMP,8" $ 17.25 LF Culvert, CMP, 12" $ 26.45 LF Culvert,CMP, 15" $ 32.73 LF Culvert,CMP, 18" $ 37.74 LF Culvert, CMP,24" $ 53.33 LF Culvert,CMP,30" $ 71.45 LF Culvert, CMP,36" $ 112.11 LF Culvert,CMP,48" $ 140.83 LF Culvert,CMP,60" $ 235.45 LF Culvert,CMP,72" $ 302.58 LF I Page 6 of 9 SUBTOTAL 24,786.61 Unit prices updated: 02/12/02 `KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 site Improvement t3ona Quantity vVorKsheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements DRAINAGE CONTINUED &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost Culvert,Concrete,8" $ 21.02 LF Culvert,Concrete, 12" $ 30.05 LF Culvert,Concrete, 15" $ 37.34 LF Culvert,Concrete, 18" $ 44.51 LF _ Culvert,Concrete,24" $ 61.07 LF - J Culvert,Concrete,30" $ 104.18 LF Culvert,Concrete,36" $ 137.63 LF Culvert,Concrete,42" $ 158.42 LF Culvert,Concrete,48" $ 175.94 LF Culvert,CPP,6" $ 10.70 LF Culvert,CPP,8" $ 16.10 LF 40 644 Culvert,CPP, 12" $ 20.70 LF 221 4574.7 Culvert, CPP, 15" $ 23.00 LF Culvert,CPP, 18" $ 27.60 LF Culvert,CPP,24" $ 36.80 LF Culvert, CPP,30" $ 48.30 LF Culvert,CPP,36" $ 55.20 LF Ditching $ 8.08 CY Flow Dispersal Trench (1,436 base+) $ 25.99 LF 50 2735.5 French Drain (3'depth) $ 22.60 LF Geotextile,laid in trench,polypropylene $ 2.40 SY Infiltration pond testing $ 74.75 HR Mid-tank Access Riser,48"dia, 6'deep $ 1,605.40 Each Pond Overflow Spillway $ 14.01 SY Restrictor/Oil Separator, 12" $ 1,045.19_ Each 1 1045.19 Restrictor/Oil Separator, 15" $ 1,095.56 Each Restrictor/Oil Separator, 18" $ 1,146.16 Each Riprap,placed $ 39.08 CY Tank End Reducer(36"diameter) $ 1,000.50 Each 2 2001 Trash Rack, 12" $ 211.97 Each Trash Rack, 15" $ 237.27 Each Trash Rack, 18" $ 268.89 Each Trash Rack,21" $ 306.84 Each Page 7 of 9 SUBTOTAL 11000.39 Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 one Improvement Bona Quantity vVorKsheet Existing Future Public Private Bond Reduction` Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit _ Quant. Price Quant. Cost Quant. I Cost Complete Cost - ------- ------------ PARKING LOT SURFACING 2"AC,2"top course rock&4"borrow $ 15.84 SY 2"AC, 1.5" top course& 2.5"base course $ 17.24 SY 4"select borrow $ 4.55 SY 1.5"top course rock&2.5"base course $ 11.41 SY WRITE-IN 4TEMS AC Road 4"CI B over 6"Crushed Road $ 22.00 SY 280 6,160.00 7"Porous Conc over 9"Crushed Road $ 33.00 SY 479 15,807.00 5"PCC Driveway over 4"crushed rock Driveway $ 25.00 SY 1 168 4,200.00 7"Porous Conc over 9"Crushed Driveway $ 33.00 SY 483 15,939.00 110"x 171"Arch CMP 5 x 1 corrug. 10 gage $ 470.00 LF 85, 39,950.00 SDS Settling Facility $ 7,500.00 EA. 1 7,500.00 ?PG Stormfilter $27,500.00 EA. 1 27,500.00 SF LF LF SUBTOTAL 117,056.00 SUBTOTAL(SUM ALL PAGES): 1,187.68 193,315.44 30%CONTINGENCY&MOBILIZATION: 356.30 57,994.63 GRANDTOTAL: 1,543 98 251,310.07 COLUMN: B C D E Page 8 of 9 Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 4/22/02 2011-06-03 KC BOND QUANTITY WORKSHEET Report Date: 6/6/2011 RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY RENTON, WA 98057 DECLARATION OF COVENANT PROHIBITING USE OF LEACHABLE METALS Grantor: d Z I ON I M UU SN Eun. LL L Grantee: City of Renton Legal Description: 141,.; eltS1 301 FEE'( Of /4E ND2714 '/L Of 1E4t: N02111 V2. OF 1!/E I i0iLiIkIJrsi 114 OP '1146 50oii6mi 1/4 LASS CO ROAD ( 44. StwARE 110 I .03 A(sltsl. Additional Legal(s)on: Assessor's Tax Parcel ID#: 13 12- 1)0q• q D IN CONSIDERATION of the approved City of Renton DC UC-LDPMUf 1 MADAM permit for application file No.LUA/SWP 0 - 014 relating to real property legally described above,the undersigned as Grantor(s),declares(declare)that the above described property is hereby established as having a prohibition on the use of leachable metals on those portions of the property exposed to the weather for the purpose of limiting metals in stormwater flows and is subject to the following restrictions. The Grantor(s)hereby covenants(covenant)and agrees(agree)as follows: no leachable metal surfaces exposed to the weather will be allowed on the property. Leachable metal surfaces means a surface area that consists of or is coated with a non-ferrous metal that is soluble in water. Common leachable metal surfaces include,but are not limited to,galvanized steel roofing,gutters,flashing, downspouts,guardrails, light posts,and copper roofing. City of Renton or its municipal successors shall have a nonexclusive perpetual access easement on the Property in order to ingress and egress over the Property for the sole purposes of inspecting and monitoring that no leachable metal is present on the Property. This easement/restriction is binding upon the Grantor(s),its heirs,successors,and assigns unless or until a new drainage or site plan is reviewed and approved by the City of Renton or its successor. IN WITNESS WHEREOF,this Declaration of Covenant is executed this day of ,20 GRANTOR,owner of the Property GRANTOR, owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me known to be the individual(s)described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed,for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 . Printed name Notary Public in and for the State of Washington, residing at My appointment expires RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OR RENTON 1055 SOUTH GRADY WAY RENTON, WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF STORM W A T E R FACILITIES AND BMPS Grantor: 0/10 1d Il\iUesTMCI.C(S.L L L Grantee:City or Renton Legal Description: �>k�'f 13 D 0 !%! DP Tlkl: ND 2�f 112. o F 71fi �I/b2 1/z EF lite hiDECV- 1 1/4 bi 11h SO01- AST 1/4 L8SS CO ibno L44, btb cta Oa-t& feel 1 .DS AcIL51 Additional Legal(s)on: Assessor's Tax Parcel ID#: 2 �:'O - g D q D IN CONSIDERATION of the approved City or Renton VCVELOPPItia i&b:Whi,l(.3 permit for application file No.LUA/S WP C)23' DI—4- relating to the real property("Property") described above,the Grantor(s),the owner(s)in fee of that Property,hereby covenants(covenant)with the City or Renton,a political subdivision of the state of Washington,that he/she(they)will observe,consent to,and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 below with regard to the Property,and hereby grants(grant)an easement as described in Paragraphs 2 and 3. Grantor(s)hereby grants(grant),covenants(covenant),and agrees(agree)as follows: 1. The Grantor(s)or his/her(their)successors in interest and assigns("Owners")shall at their own cost,operate,maintain,and keep in good repair,the Property's stormwater facilities and best management practices("BMPs")identified in the plans and specifications submitted to King County for the review and approval of permit(s)#: . Stormwater facilities include pipes,swales,tanks,vaults,ponds,and other engineered structures designed to manage stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices,native vegetated areas,permeable pavements,vegetated roofs,rainwater harvesting systems,reduced impervious surface coverage,and other measures designed to reduce the amount of stormwater runoff on the Property. 2. City or Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct other activities specified in this Declaration of Covenant and in accordance with RMS 4-6-030. This right of ingress and egress,right to inspect,and right to perform required maintenance or repair as provided for in Section 3 below,shall not extend over those portions of the Property shown in Exhibit"A." 3. If City of Renton determines that maintenance or repair work is required to be done to any of the stormwater facilities or BMPs,City of Renton shall give notice of the specific maintenance and/or repair work required pursuant to RMC 4-6-030. The City shall also set a reasonable time in which such work is to be completed by the Owners. If the above required maintenance or repair is not completed within the time set by the City,the City may perform the required maintenance or repair,and hereby is given access to the Property,subject to the exclusion in Paragraph 2 above,for such purposes. Written notice will be sent to the Owners stating the City's intention to perform such work. This work will not commence until at least seven(7)days after such notice is mailed. If,within the sole discretion of the City,there exists an imminent or present danger,the seven(7)day notice period will be waived and maintenance and/or repair work will begin immediately. 4. If at any time the City of Renton reasonably determines that a stormwater facility or BMP on the Property creates any of the hazardous conditions listed in KCC 9.04.130 or relevant municipal successor's codes as applicable and herein incorporated by reference,The City may take measures specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair work completed by the City as described in Paragraph 3 or any measures taken by the County to address hazardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the County within thirty(30)days of the receipt of the invoice for any such work performed. Overdue payments will require payment of interest at the current legal rate as liquidated damages. If legal action ensues,the prevailing party is entitled to costs or fees. 6. The Owners are hereby required to obtain written approval from City of Renton prior to filling,piping,cutting,or removing vegetation(except in routine landscape maintenance)in open vegetated stormwater facilities(such as swales,channels,ditches,ponds,etc.),or performing any alterations or modifications to the stormwater facilities and BMPs referenced in this Declaration of Covenant. 7. Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery,or three(3)days after mailing by Certified Mail, return receipt requested. 8. With regard to the matters addressed herein,this agreement constitutes the entire agreement between the parties,and supersedes all prior discussions,negotiations,and all agreements whatsoever whether oral or written. 9. This Declaration of Covenant is intended to protect the value and desirability of the real property described above,and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s),and Grantor's(s')successors in interest,and assigns. 3 10. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records.IN WITNESS WHEREOF,this Declaration of Covenant for the Inspection and Maintenance of Stormwater Facilities and BMPs is executed this day of ,20 . GRANTOR,owner of the Property GRANTOR,owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me known to be the individual(s)described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed,for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 Printed name Notary Public in and for the State of Washington, residing at My appointment expires X. MAINTENANCE AND OPERATIONS MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL.CONVEYANCE,AND WQ FACILITIES NO. 3-DETENTION TANKS AND VAULTS Maintenance Defect or Problem Component Conditions When Maintenance is Needed Results Expected When Storage Area Maintenance is Performed Plugged Air Vents One-half of the cross section of a vent is blocked Vents free of debris and sediment at any point with debris and sediment. Debris and Sediment Accumulated sediment depth exceeds 10%of All sediment and debris removed the diameter of the storage area for V2 length of from storage area. storage vault or any point depth exceeds 15%of diameter. Example:72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than'A length of tank. Joints Between Any crack allowing material to be transported into All joint between tank/pipe sections Tank/Pipe Section facility. are sealed Tank Pipe Bent Out of Any part of tank/pipe is bent out of shape more Tank/pipe repaired or replaced to Shape than 10%of its design shape. Vault Structure design. Damage to Wall, Cracks wider than 1/2-inch and any evidence of Vault replaced or repaired to design Frame,Bottom, soil particles entering the structure through the and/or Top Slab cracks,or maintenance inspection personnel specifications. determines that the vault is not structurally sound. Damaged Pipe Joints Cracks wider than%:-inch at the joint of any No cracks more than'V4-inch wide at inlet/outlet pipe or any evidence of soil particles the joint of the inlet/outlet pipe. entering the vault through the walls. Manhole Cover Not in Place Cover is missing or only partially in place.Any Manhole is closed. open manhole requires maintenance. Locking Mechanism Mechanism cannot be opened by one Not Working maintenance person with proper tools.Bolts into Mechanism opens with proper tools. frame have less than%inch of thread(may not apply to self-locking lids.) Cover Difficult to One maintenance person cannot remove lid after Cover can be removed and Remove applying 80Ibs of lift. Intent is to keep cover from reinstalled by one maintenance sealing off access to maintenance. person. Ladder Rungs Unsafe King County Safety Office and/or maintenance Ladder meets design standards. person judges that ladder is unsafe due to Allows maintenance person safe missing rungs, misalignment,rust,or cracks. access. Large access Gaps,Doesn't Cover Large access doors not flat and/or access hole Doors closes flat and covers access doors/plate Completely not completely covered. NOTE however that hole completely. grated doors are acceptable. Lifting Rings Missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to remove lid. Rusted or lid. 1/24/2005 2005 Surface Water Design Manual—Appendix A A-4 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Component Results Expected When Maintenance is Performed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (Includes Sediment) orifice plate is less than 1.5 feet. Structural Damage Structure is not securely attached to manhole Structure securely attached to wall wall and outlet pipe structure should support at and outlet pipe. least 1,000 lbs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 10%from plumb). Connections to outlet pipe are not watertight and Connections to outlet pipe are water show signs of rust. tight;structure repaired or replaced and works as designed. Any holes—other than designed holes—in the Structure has no holes other than structure_ designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 50%of its surface area. Gate is repaired or replaced to meet design standards. Orifice Plate Damaged or Missing Control device is not workingproperly pro eri due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions and potential of blocking)the overflow pipe. works as designed. Manhole See"Detention Tanks See"Detention Tanks and Vaults"Table No.3 See"Detention Tanks and Vaults" and Vaults" Table No.3 2005 Surface Water Design Manual–Appendix A A-5 1/24/2005 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL.CONVEYANCE.AND WQ FACILITIES NO. 5-CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash&Debris Trash or debris of more than %z cubic foot which No Trash or debris located (Includes Sediment) is located immediately in front of the catch basin immediately in front of catch basin opening or is blocking capacity of the basin by opening. more than 10%. Trash or debris(in the basin)that exceeds 'Is the No trash or debris in the catch depth from the bottom of basin to invert the basin. lowest pipe into or out or the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outlet pipes free cf trash or (r more than /a of its height debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.. methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Structure Damage to Corner of frame extends more than 3/,inch past Frame is even with curb. Frame and/or Top curb face into the street(If applicable). Slab Top slab has holes larger than 2 square inches or cracks wider than '4 inch(intent is to make Top slab is free of holes and cracks. sure all material is running into basin). Frame not sitting flush on top slab,i.e.. Frame is sitting flush on top slab. separation of more than'S inch of the frame from the top slab. Cracks in Basin Cracks wider than 54 inch and longer than 3 feet. Basin replaced or repaired to design Walls/Bottom any evidence of soil particles entering catch standards. basin through cracks,or maintenance person judges that structure is unsound. Cracks wider than V2 inch and longer than 1 foot No cracks more than '/,inch wide at at the joint of any inlet/outlet pipe or any the joint of inlet/outlet pipe. evidence of soil particles entering catch basin through cracks. Settlement/ Basin has settled more than 1 inch or has rotated Basin replaced or repaired to design Misalignment more than 2 inches out of alignment. standards. Fire Hazard Presence of chemicals such as natural gas,oil No flammable chemicals present. and gasoline. Vegetation Vegetation growing across and blocking more No vegetation blocking opening to than 10%of the basin opening. basin. Vegetation growing in inlet/outlet pipe joints that No vegetation or root growth is more than 6 inches tall and less than 6 inches present. apart. Pollution Nonflammable chemicals of more than'/cubic No pollution present other than foot per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missingonly or partially in place.Any Catch basin cover is closed open catch basin requires.maintenance. Locking Mechanism Mechanism cannot be opened by on Mechanism opens with proper tools. Not Working maintenance person with proper tools. Bolts into frame have less than%2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 lbs.of lift;intent is keep cover from 1 maintenance sealing off access to maintenance. person. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, Ladder meets design standards misalignment,rust, cracks, or sharp edges. allows maintenance person safe access. 1/24/2005 2005 Surface Water Design Manual--Appendix A A-6 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL.CONVEYANCE.AND WQ FACILITIES NO. 5-CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed I Results Expected When Component f J Maintenance is performed Metal Grates Unsafe Grate Grate with opening wider than '13 inch. i Grate opening meets design (If Applicable) Opening standards. Trash and Debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. Damaged or Missing. i Grate missing or broken member(s)of the grate. Grate is in place and meets design standards. NO. 6- DEBRIS BARRIERS (E.G.. TRASH RACKS) Maintenance Defect or Problem Condition When Maintenance is Needed I Results Expected When Component Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20% Barrier clear to receive capacity of the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than%inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50% Repair or replace barrier to design deterioration to any part of barrier. standards. NO. 7-ENERGY DISSIPATERS Maintenance Defect cr Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed. External: Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design standards. Rock area five square feet or larger,or any exposure of native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that t Sediment design depth. matches design_ Not Discharging Visual evidence of water discharging at Trench must be redesigned or Water Properly concentrated points along trench(normal rebuilt to standards. condition is a"sheet flow"of water along trench). Intent is to prevent erosion damage. Perforations Plugged. Over'A of perforations in pipe are plugged with Clean or replace perforated pipe. debris and sediment. Water Flows Out Top Maintenance person observes water flowing out Facility must be rebuilt or of"Distributor"Catch during any storm less than the design storm or redesigned to standards. Basin. its causing or appears likely to cause damage. Receiving Area Over- Water in receiving area is causing or has No danger of landslides. Saturated potential of causing landslide problems. Internal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to'A or Replace structure to design Post. Baffles,Side of original size or any concentrated worn spot standards. • Chamber exceeding one square foot which would make structure unsound. 2005 Surface Water Design Manual—Appendix A 1.24/700; A_7 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL.CONVEYANCE.AND WO FACILITIES NO. 10-CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sediment and diameter of the pipe. debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. Any dent that decreases the cross section area f Pipe repaired or replaced_ of pipe by more than 20%. Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion Damage to See"Detention Ponds"Table No. 1 Slopes See"Detention Ponds"Table No. 1 Rock Lining Out of Maintenance person can see native soil beneath Replace rccks to design standards. Place or Missing(If the rock lining. Applicable). NO. 11 -GROUNDS (LANDSCAPING) Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected petted When Maintenance is Performed General Weeds Weeds growing in more than 20%of the Weeds present in less than 5%of (Nonpoisonous,not landscaped area(trees and shrubs only). the landscaped area. noxious) Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation present in vegetation. landscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic Area clear of litter. foot within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% broken which affect more than 25%of the total of total foliage with split or broken foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of injury. knocked over. Trees or shrubs which are not adequately Tree or shrub in place and supported or are leaning over, causing exposure adequately supported;remove any of the roots. dead or diseased trees. 2005 Surface Water Design Manual—Appendix A A-9 1/24/2005 APPENDIX •9461'+.',14.514Pn (fr4Q)-5 '7)-y1/2Q41Q�73,-/ c #Y71715`/ 7 ;r-{v5 '4o sz1 h�17 S f 0-1-9.117 (9/55 J O 1 A ¢.L 'no7 35(1 41rffVti,-• °k C&- In F q yd1-1 Ott: h 1 71??q -mm4 d° 40 7 y) ,i1 •t�Inc� li -11)5110a.5 htzt Z- /7C1SL 'e'r44'Vc0 70040d u1Q7 j9 f2f vae?l 473 099 •Ar'74 vwnrald 3 SO 1 (ki f 01119 11444 "PS44777/12,/c ) O•Z=?lam L-7navA sria) $ L Q151- 'm k/ '2,0I2 (11??) 7z44,JCfnn nvs h:7/5"' h bl = 74/#0 91 x I IO/J ►1n d'sdt-l -2 Pklaccd_ ()W Zil 4,iticc ? 13a) lw rd17I cb?hi 2, Newt L rd171 b( Thkv 2noaJ 90,c1ry a Vo3j. 0) 24Q:, 3" y 9rytio 0417.9 lamasv a'1 N07 coOVQci at-b-b i ca no (/z «4a-,)qi,. ,-ru-i A33 StreetPave Pavement Design & Analysis Software American Concrete Pavement Association Report for Concrete Pavement Design Project Name: Talbot Road Townhomes Route: Location: Renton, Washington Project Description: Residential 18 unit townhome project Owner/Agency: Y and L Investment Design Engineer: Hal Hagenson, P.E. Recommended Concrete Pavement Design Cross-Section Thickness 6.5 in Joint Spacing 11.38 ft Dowel Bars N/A subgrade Effect of Rounding on Thickness Exact design thickness = 6.4 in Theoretical Life of Rounded-Up Concrete Thickness Rounded-Up Thickness 26 years @ 85% reliability Reliability of Rounded-Up Concrete Thickness 6.5 in 88.2% reliability for 20-year design Expected Life of Rounded-Down Concrete Thickness Rounded-Down Thickness 7 years @ 85% reliability Reliability of Rounded-Down Concrete Thickness 6 in 66.1% reliability for 20-year design Inputs Design Life 20 years Traffic Traffic Category: Residential Total Number of Lanes 2 Direction Distribution 50 Design Lane Distribution 100 ADTT 3 per day (average daily truck traffic, two-way, all lanes) Truck Traffic Growth 2% per year '1/41/.11111 4•40•C,1D11A C.,n i.,<m• 41n1 Llnnoncnn D C Orme' nf4 StreetPave Pavement Design & Analysis Software American Concrete Pavement Association Support Conditions Subgrade: CBR (California Bearing Ratio) 7 or R-Value (Resistance Value) 11 Resilient Modulus of the Subgrade 7640 psi MRSG (psi) = 1941.488 * CBR A (0.6844709) MRSG (psi) = 2165.935 * e A (0.0343507 * R-value) Subbase: Layer 1 = Not Selected Modulus = 0 psi Thickness = 0 in Layer 2 = Not Selected Modulus = 0 psi Thickness = 0 in Layer 3 = Not Selected Modulus = 0 psi Thickness = 0 in Composite Modulus of Subgrade Reaction (K-value): k = 394 psi/in Concrete Properties Flexural Strength (Modulus of Rupture, MR) = 375 psi Modulus of Elasticity = 2531250 psi Modulus of Elasticity (E) =6750 x MR Design Features Load Transfer Devices (Dowel Bars) Needed? No Diameter= N/A Edge Support? No (widened lane, tied concrete shoulder, or curb& gutter) '1/1.1/01-111 )•l o•g')Dm.i of StreetPave Pavement Design & Analysis Software American Concrete Pavement Association Reliability Specified Reliability = 85% Allowable Percent Cracked Slabs at End of Design Life = 25% Fatigue & Erosion Calculations Traffic Category:Residential Fatigue Analysis Erosion Analysis Axle Axles per Expected Stress Allowable Fatigue Allowable Erosion Load,kips 1000 Trucks Repetitions Ratio Repetitions Consumed Power Repetitions Consumed Single Axles 22 0.96 31 0.862 132 23.28 89.135 131826 0.02 20 4.23 135 0.788 386 35.01 73.666 225218 0.06 18 15.81 505 0.714 1671 30.22 59.67 408374 0.12 16 38.02 1214 0.639 13235 9.17 47.147 801694 0.15 14 56.11 1791 0.564 280267 0.64 36.098 1762428 0.1 12 124 3959 0.488 32863042 0.01 26.522 4633775 0.09 10 204.96 6544 0.411 unlimited 0 18.418 17153746 0.04 8 483.1 15424 0.333 unlimited 0 11.788 184177966 0.01 6 732.28 23379 0.254 unlimited 0 6.631 unlimited 0 4 1693.31 54062 0.174 unlimited 0 2.948 unlimited 0 Tandem Axles 36 4.19 134 0.576 153604 0.09 61.926 367592 0.04 32 69.59 2222 0.516 4295544 0.05 48.929 720214 0.31 28 68.48 2186 0.455 584548720 0 37.461 1576573 0.14 24 39.18 1251 0.394 unlimited 0 27.523 4105983 0.03 20 57.1 1823 0.332 unlimited 0 19.113 14819790 0.01 16 75.02 2395 0.269 unlimited 0 12.232 139609108 0 12 139.3 4447 0.205 unlimited 0 6.881 unlimited 0 8 85.59 2733 0.14 unlimited 0 3.058 unlimited 0 4 31.9 1018 0.073 unlimited 0 0.765 unlimited 0 0 0 0 0 unlimited 0 0 unlimited 0 Tridem Axles 52 0 0 0.558 366625 0 43.731 997719 0 46 0 0 0.497 15424773 0 34.222 2072177 0 40 0 0 0.436 unlimited 0 25.877 5026039 0 34 0 0 0.374 unlimited 0 18.696 16161810 0 28 0 0 0.312 unlimited 0 12.68 109259557 0 22 0 0 0.249 unlimited 0 7.828 unlimited 0 16 0 0 0.184 unlimited 0 4.14 unlimited 0 10 0 0 0.119 unlimited 0 1.617 unlimited 0 4 0 0 0.05 unlimited 0 0.259 unlimited 0 0 0 0 0 unlimited 0 0 unlimited 0 Total Fatigue Used: 98.47 Total Erosion Used: 1.12 7111 V)/)11 4•10•G')Onn D,n, 1 of 1 Effect of k-value on Thickness 8 84 8 U) 76 CD C.) .0 7.2 I- 6.8 6.4 6 5U 100 150 200 250 300 350 400 450 500 550 600 k-value, psi/in. r agc i vi J Hal Hagenson From: David A. Clark[dclark@clarkarchitects.com] Sent: Wednesday, August 22, 2007 3:36 PM To: 'Hal Hagenson' Subject: RN:Aerial Ladder more From: Brian Wiwel [maitto:bwiwel@ci.seatac.wa.us] Sent Monday, March 05, 2007 8:00 AM To: David A. Clark Subject RE: Aerial Ladder Platform weights. Weights are estimated in-service weights Front GVWR= 19,040# Rear GVWR= 50,600# Total GVWR=69,640 The truck would have a single front axle with single tires and tandem rear axles with dual tires Front tire contact area will be 115.8 sq inches per tire and the rear tires each will be 83.0 sq inches per tire. Spacing between the tandem axles will be 52 inches and spacing from front axle to first tandem axle will be 229 inches, and spacing from front axle to second tandem axle will be 281 inches. Brian. Brian Wiwel, Assistant Chief City of SeaTac Fire Department 2929 South 200th Street SeaTac, Washington 98198 206-973-4500 Bwiwel@ci.seatac.wa.us From: David A. Clark [mailto:ddark@clarkarchitecls.com] Sent: Friday, March 02, 2007 3:03 PM To: Brian Wiwel Subject: FW: Aerial Ladder 8/22/2007 PIONEER ENGINEERING, INC. Geotechnical Engineering •Earth Science •Water Resources December 6, 2010 Mr. Yan Lifshaz Libros Construction, Inc. P. 0. Box 53046 Bellevue, WA 98015 Subject: Design Parameters for Percolated Concrete Pavement (PCP) Proposed Talbot Road Townhomes 4701 Talbot Road South Renton, Washington PEI Project No. G715P Dear Mr. Lifshaz: At your request, Pioneer Engineering, Inc. (PEI) has completed on-site infiltration and California Bearing Ratio (CBR) tests and based on the test results provides recommendations for design parameters of PCP. It is our understanding that the PCP would be constructed in the community driveway at the subject site in Renton, Washington. A site plan is shown on Figure 1. CBR Testing CBR is a penetration test determined as the greater ratio value of the test resistance at 0.1-inch and 0.2-inch penetrations to the standard resistance of crushed rock at the corresponding penetrations. It provides an index value generally used to design a pavement section. The soil (weathered till; silty sand) sample was placed and sealed in two 5-gallon buckets, carefully transported for testing. It was tested in general accordance with the procedures designated as ASTM D1883, adopting the compactive efforts of a modified proctor at or near the sample's optimal moisture content. The test specimen was compacted by a mechanical hammer with compactive efforts at 50, 25 and 10 blows per layer, after the sample had been soaked in water for 96 hours and its swelling amount measured. The test results indicate that CBR values of 42.2, 22.5 and 7.4 corresponding to 100, 95.1 and 90.3 percent of compaction, respectively. We recommend that the CBR value of 7.4 be used for relatively undisturbed P. 0.Box 33628,Seattle,WA 98133 Phone: (206)427-9118 •Fax: (206)306-2982 December 6,2010 Design Parameters for Percolated Pavement PEI Project No.G715P Page 2 subgrade. A CBR value of 21.8, after an empirical factor of 92.5 percent of energy correction applied to covert the compactive efforts of the modified proctor to the standard proctor, should be used to model the same soils when used as engineered fill over suborade. On-Site Infiltration Tests Field infiltration tests were conducted in general accordance with the procedures outlined in the Surface Water Design Manual, published in September, 1998 by Department of Natural Resources, King County, Washington, with reference to the updated 2005 version. The testing mythology is derived from the EPA test guideline of the "Falling Head Percolation Test Procedure" in the publication On-Site Wastewater Treatment and Disposal Systems released in 1980. Hand-dug holes with a diameter of 6 inches by 16 inches deep into the firm native soils (test soils) which would be used as subgrade for PCP. The bottom of each hole was first placed with 2-inch-thick clean pea gravel of 1/2 to 3 inch in size, and then tap water was carefully dispersed into the hole for a substantially long period of time to soak the test soils at a minimum hydraulic head of 12 inches. The hole was then filled up to have a hydraulic head of 6 inches and the water level drop measured over elapsed time to determine the infiltration rate of the test soils. The test is continued until two consecutive drops of water levels vary no more than 1/16 inch within a 90-minute period. Based on the test results, we recommend that an infiltration rate of 0.11 in/hr, including a factor of safety of 3, be employed for PCP design. r. Respectfully sub '�_,,� w ,aw PIONEER ENGIt�^It . ,4c :, - a n p ,- z * 35226 r' i► _ NAL Joseph Wu, P.a SS/zoI,- Consulting Geotechnica �ngmeer ---" Figure 1 - Site Plan PIONEER ENGINEERING, INC. PIONEER ENGINEERING, INC. Geotechnical Engineering •Earth Science •Water Resources July 3, 2007 Mr. Yan Lifshaz Y & L Enterprises, LLC DRAFT P. O. Box 5757 Bellevue, WA 98008 Subject: Geotechnical Engineering Study Proposed Duplex Buildings 4701 Talbot Road South Renton, Washington PEI Project No. G715 Dear Mr. Lifshaz: At your request, we have completed a geotechnical engineering study for the proposed development at the subject address in Renton, Washington. The general location of the site is shown on Figure 1 - Vicinity Map. The proposed development would consist of nine duplex residential buildings and an access driveway. Each duplex building would likely be a three- story, wood-framed structure with an attached garage for an individual dwelling unit. The concrete slabs of the garage and bonus space would be supported on grade. OVERVIEW According to a topographic survey plan, prepared by Poggemeyer Design Group, dated August 17, 2005, the site is located in a portion of the NE quarter of Section 17, Township 23 North, Range 5 East, W.M., Washington. The legal description of the site is as follows: LOTS 1 AND 2, BLOCK 1, SMITHER'S SIXTH ADDITION TO THE TOWN OF RENTON, ACCORDING TO THE PLAT THEREOF, RECORDED IN VOLUME 26 OF PLATS, PAGE 47, IN KING COUNTY, WASHINGTON. PURPOSE AND SCOPE OF SERVICES The purpose of this geotechnical engineering study is to characterize the subsurface soil and groundwater conditions by test pit excavations, and use such information obtained to provide recommendations for the proposed development of new residential dwelling units. To achieve the purpose, the scope of our services specifically comprises the following items: P. O. Box 33628,Seattle,WA 98133 Phone: (206)427-9118•Fax: (206)306-2982 July 3,2007 Geotechnical Engineering Study PEI Project No.G715 Page 2 1. Conduct subsurface exploration with five test pits to a depth of about 10 feet or to bearing soils, whichever is reached first. The soils encountered are visually classified. 2. Review geologic and soil conditions at the site based on a published geologic map. 3. Address geologic hazards and mitigation measures, as required. 4. Prepare a written report to address our findings and conclusions of this study, and provide geotechnical recommendations for site preparation and grading, engineered fill, excavation and slope, foundation support, and drainage systems, etc. It should be noted that our geotechnical recommendations are based on the soil conditions encountered in test pits, and our engineering analyses, experience and engineering judgment. The conclusions and interpretations in this report, however, should not be construed as a warranty of the subsurface conditions. Soil and groundwater conditions stated in this report may vary from those actually encountered during construction. If variations appear then, we should be retained to re-evaluate the recommendations of this report, and to verify or modify them in writing prior to proceeding with the subsequent work on site. INVESTIGATIONS SUMMARY Subsurface conditions at the site were explored with five test pits to depths varying from 6.5 to 10 feet on June 28, 2007, using a track-mounted excavator (John Deere 135C) owned and operated by Behnke & Sons Excavating, LLC. Locations of test pits are determined by tape measurements with reference to the existing surface features shown on the provided topographic survey plan. They should be considered as only accurate to the measuring method used. Approximate locations of test pits are shown on Figure 2. The subsurface exploration was continuously monitored by an engineer from our firm who documented the soil and groundwater conditions encountered, maintained a log of each test pit, and observed pertinent surface features. The final test pit logs represent our interpretations of the subsurface conditions encountered in the pits. The stratification lines on the logs indicate the approximate boundaries between soil types, and the actual transitions may be more gradual in the natural geologic setting. The soils encountered by the pits were visually classified in general accordance with Unified Soil Classification System (USCS) as shown on Figure 3. PIONEER ENGINEERING,INC. July 3.2007 Geotechnical Engineering Study PEI Project No.G715 Paee 3 SITE CONDITIONS LOCATION AND SURFACE CONDITIONS The site is a developed property, situated near the toe of a regional slope descending westerly to the floodplain of Green River. It is about trapezoidal in shape, bounded to the east by Talbot Road South, and adjoins properties on the other three sides. It is measured about 166 feet along Talbot Road South and about 248 and 249.4 feet, respectively, in depths, encompassing an area of about 0.95 acre. Currently, there are a two-story, single-family residential building and a detached garage occupying approximately the central portion of the site, accessed by a concrete ramp from Talbot Road South. An additional earth access ramp is located near the SE corner of the site. An existing rockery is lined along the east property boundary to support a minor cut and two access ramps of up to about 4 feet in height. The ground surface within the site is fairly flat. sloping down westerly at an average gradient of 9.6 percent. Landscaped grass is the dominant vegetative cover mantling over the open space, with a few clusters of deciduous trees and individual mature coniferous trees located along the north property line and in the interior of the site. GEOLOGIC SETTING Geologic Map of the Renton Quadrangle, King County, Washington, by D. R. Mullineaux, published by U. S. Geological Survey in 1965, was referenced for the geologic and soil conditions at the site. According to this publication, the surficial soil unit at the site is mapped as Ground Moraine Deposits (Qgt). As described in this publication, Ground Moraine Deposits consist mostly of thin Ablation Till over Lodgment Till. Lodgment Till is generally a compact, coherent, unsorted mixture of sand, silt, clay, and gravel; locally termed as "hardpan." Ablation Till is of similar soil composition but less coherent and compact. SUBSURFACE SOIL CONDITIONS In general, test pits first encountered 8 or 12 inches of landscaping topsoil and lawn grass, underlain by 18 to 22 inches of fill consisting of brown, silty, fine sand with a trace of coarse PIONEER ENGINEERING,INC. July 3.2007 Geotechnical Engineering Study PEI Project No.6715 Page 4 gravel in a loose condition. With the exception of the relic topsoil underlying fill in Test Pit 1 (TP-1), a thin layer of Ablation Till was observed to underlie fill in the remaining pits. Ablation Till was composed of grayish brown, silty, fine to medium sand with a trace of fine gravel and .......... occasional cobble. The soil mass in this soil unit generally contained some orange staining indicative of oxidation. Underlying_Ablation Till to the termination_depths in all pits was Lodgment Till of a similar soil composition as Ablation Till but denser, slightly cemented and no orange staining contained. Detailed information for the subsurface conditions explored in test pits is presented on Figures 4 to 6. GROUNDWATER CONDITIONS Very-light to light groundwater was encountered at a depth of 3 feet in two of five test pits. The water appears to be the infiltrated storm runoff perching above the less permeable Ablation Till. The amount and flow rate of groundwater generally decrease with time while advancing into drier months (generally between April 1 and September 31 of a year). In general, groundwater levels fluctuate with seasons, depending on the amount of precipitation and surface runoff, denseness of vegetative cover on the ground, purpose of land use, and other factors. DISCUSSIONS AND CONCLUSIONS Based on the soil and groundwater conditions encountered in our subsurface exploration, it is our opinion that, from a geotechnical engineering viewpoint, the site is suitable for the proposed development of duplex residential buildings. Conventional spread footings bearing on medium- dense Ablation Till, on dense Lodgment Till, or on engineered fill with proper compaction efforts should be able to provide adequate support for the proposed buildings. The above two till soils, t_._ however, are generally.of low to very-low permeability in the natural state, and they are not in support for the installation of a stormwater infiltration system to discharge the collected stormwater. According to Liquefaction Susceptibility for the Renton 7.5-Minute Quadrangle, Washington by Stephen P. Palmer, Henry W. Schasse and David K. Norman, published by Washington State Department of Natural Resources in 1994, the liquefaction susceptibility of the site is mapped in a Category III zone of low risk. This mapping is in agreement with our conclusion that the prevailing existence of strong till soils underlying the site and lack of a shallow, constant PIONEER ENGINEERING, INC. July 3.2007 Geotechnical Engineering Study PEI Project No.G715 Page 5 groundwater table would minimize the potential risk of liquefaction to occur at the site during seismic events. RECOMMENDATIONS SITE GRADING AND EARTHWORK Site preparation should include clearing and grubbing of vegetative cover, installation of temporary erosion control measures, removal of demolishment debris, and stabilization of the exposed subgrade. Prior to starting construction activities, a filter fence should be installed along the lower boundary of the construction limits; the entrance, parking, and loading areas for construction vehicles should be paved with a layer of 12 inches thick quarry spalls (2 to 4 inches in size) to guard against the sediments migrating into lower neighboring properties or being tracked onto the public roadway. A layer of non-woven geotextile or a filter bag should be inserted into each stormwater inlet in the downstream area outside the construction limits. The above implementations serve as temporary erosion/sediment control measures during construction, and they must remain in place until construction is complete. Clearing of ground includes stripping and grubbing of all surface vegetation within the construction limits. Occasional overexcavation may be required when encountering the root ball zone of a mature tree or localized weak soil pockets. The overexcavation should be backfilled with engineered fill and compacted to a non-yielding condition, following the recommendations stated in ENGINEERED FILL AND COMPACTION. The landscaping and relic topsoil and fill over the site generally contain organic and other deleterious substances and are unsuitable for reuse in areas to withstand loads. They should be stockpiled separately from the soils qualified to be used as engineered fill. After the topsoil, fill, weak surficial soils and demolishment debris have been removed, the exposed subgrade soils should be proof-rolled to a non-yielding state by a fully-loaded dumptruck or other proper heavy construction equipment. Any pumping or weaving spot during proof-rolling should be re- compacted, or excavated to firm native soils and backfilled with engineered fill and stabilized with adequate compaction. PIONEER ENGINEERING,INC. July 3.2007 Geotechnical Engineering Study PEI Project No.G715 Page 6 ENGINEERED FILL AND COMPACTION Engineered fill (or structural fill) is a term of describing the material placed under footings, on- grade floor slabs and pavements, or used to construct embankments. Its composition generally compromises but occasionally combines excellent engineering properties of shear strength, permeability, and compressibility to serve design functions, depending upon areas of usage and weather conditions when used. Engineered fill should be free of demolition debris, and organic and other deleterious substances. It should consist of clean soils and meet the gradation criteria specified below: U. S. Standard Sieve Size Percent of Passing by Dry Weight 4 in. 100 No. 4 75- 100 No. 200 3-70 The on-site excavated till soils generally contain a relatively high content of fines (soil particles passing through the U.S. No. 200 sieve based on the fraction of the same material passing through the U.S. No. 4 sieve) and are difficult to compact to attain the required soil density if used in the wet weather. Proper compaction efforts should be applied to the engineered fill using a vibratory compactor. Cement or lime admixture may be used to condition the moist content in soils, in conjunction with aeration. Engineered fill should be placed no more than 10 inches per loose lift, compacted to meet the required dry soil density determined by ASTM D1557 (Modified Proctor Method) as follows: 1 Applicable Area Maximum Dry Soil Density Under Footings 95% Under Parking and Driveway 95%for upper 3 feet, 90% below Under on-Grade Floor Slab 95%for upper 2 feet, 90% below Foundation Wall Backfill 95%for upper 2 feet, 90% below Utility Trench Backfill 95%for upper 4 feet, 90% below PIONEER ENGINEERING,INC. July 3.2007 Geotechnical Engineering Study PEI Project No.G715 Page 7 CUT and FILL SLOPES Unsupported temporary cut slopes should not be greater than the limits specified by local, state, and federal government safety regulations if worker have to perform the construction work in the foundation and utility trenches. We estimate that up to about 16 feet of excavation and about 8 feet of fill will be required to establish a relatively level foundation pad for all buildings. Temporary cuts should be sloped no steeper than 1 H:1 V in the existing and relic topsoil and fill; 3/4H:1 V in Ablation or Lodgment Till. The lower 4 feet may be cut vertically into dense Lodgment Till. The above recommended inclinations of excavations are based on the assumption that no groundwater is encountered during excavation. If groundwater is encountered then, the grading work should be halted immediately and engineer be informed to re-evaluate slope stability. Proper remedial measures may be taken to stabilize the cut slope. Exposed temporary cut slopes should be covered with plastic sheets to minimize surficial erosion and sloughing by storm runoff when rain is anticipated. Fill should be placed keying into Ablation or Lodgment Till deposits with benches at a 4-foot width and 1-foot rise, followed by adequate compaction. Permanent fill or cut slopes should have an inclination no steeper than 2H:1 V. We recommend that the grading work for foundations be started and completed in drier months to minimize the adverse effects by precipitation. FOUNDATION SUPPORT Foundations of each proposed duplex building should be bearing on Ablation Till or on Lodgment Till or on adequately-compacted engineered fill placed over either one of these two till soils. For footings constructed as recommended above, our design criteria for spread footing foundations are summarized in the following: Allowable soil bearing pressure should be no more than 1,750 psf on medium-dense Ablation Till; not exceeding 2,250 psf on dense Lodgment Till; no more than 1,750 psf on engineered fill with adequate compaction placed over either one of the above two till deposits. Minimum depth to bottom of perimeter footing below adjacent exterior finish grade should be at least 18 inches to reduce the risk of the foundation damage by the frost effect. PIONEER ENGINEERING,INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G715 Page 8 Minimum width of continuous footings should be 16 inches; minimum width of individual footings should be 24 inches. Foundation and detention vault walls restrained to displace and rotate at the top are considered unyielding and should be designed for a lateral soil pressure under an "at-rest" condition. A lateral soil pressure of 45 pounds per cubic foot (pcf) of Equivalent Fluid Density (EFD) should be used for designing foundation walls, assuming the backfill is well-drained and level. The friction force between the foundation and the subgrade, and the passive soil pressure acting on the under-grade portion of the foundation provide resistance to lateral loads. For the better development of lateral resistance, the foundation must be poured directly against firm, undisturbed Ablation or Lodgment Till deposits, or directly against adequately-compacted engineered fill. We recommend that a passive soil pressure of 360 pcf of EFD be used for calculating lateral resistance, based on the assumption that the backfill is level or ascending. A coefficient of friction of 0.60 may be used to calculate the friction force between the foundation and subgrade soils. These two soil parameters are unfactored and ultimate values, and proper factors of safety should be applied for design purposes. The foundation wall should be designed to have a minimum factor of safety equal to 1.5 against sliding and overturning failures. SEISMIC CONSIDERATIONS The design of residential buildings should be in compliance with the specifications and standards stated in 2003 International Building Code (2003 IBC), with reference to 2003 International Residential Code (2003 IBC). Based on the 2003 IBC, the site is located in a zone of Seismic Design Category D (Seismic Design Category D2 in 2003 IRC) with a classified Site Class D. Proper factors of safety should be applied to the spectral response acceleration values derived from 2003 IBC. The seismic design parameters are based on the search (Longitude: -122.2095, Latitude: 47.4608) results from a USGS website (http://egint.cr.usgs.gov/eq-men/html/lookup-2002-interp- 06.html) and listed below: Regional Earthquake Ground Motion for the 0.2-Second (Short Period) Spectral Response Acceleration (2% Probability of Exceedance in 50 Years) Ss= 1.41 g PIONEER ENGINEERING,INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G7]5 Page 9 Regional Earthquake Ground Motion for the 1-Second Spectral Response Acceleration (2% Probability of Exceedance in 50 Years) S1= 0.48 g Property Coefficient Fa as a Function of Property Class and Mapped Spectral Response Acceleration at a Short Period(Ss) Fa= 1.00 Property Coefficient F, as a Function of Property Class and Mapped Spectral Response Acceleration at a 1-Second Period(Si) F„= 1.60 RETAINING STRUCTURES As addressed in the above CUT AND FILL SLOPES section, we estimate that a fill slope of about 8 feet in height is required to create a considerably level building pad for the proposed buildings. As a result, a retaining structure should be constructed along the boundary of the approximately western half of the site to support the fill slope. We recommend that a segmental block wall with geogrid reinforcements be used as a retaining structure to serve this engineering purpose. General design and installation guidelines for segmental block walls are addressed in the following: Select fill is the material used in the geogrid-reinforced area behind the wall. This fill should have the plasticity index less than 20 for the particles passing the U.S. No. 200 sieve by weight, and the particle distribution (gradation) as specified as follows: Particle Size(U. S.Sieve) Passing By Weight(%) 2 inches 100 inch 75- 100 No. 40 0- 60 No. 200 0-35 Select fill should be placed no more than 10 inches per lift in loose state, compacted to at least 95 percent of the maximum dry density determined by ASTM D1557 (Modified Proctor Method) for the top 2 feet, and no less than 90 percent for the remaining. The top 18 inches of this fill may be replaced with topsoil for landscaping. PIONEER ENGINEERING, INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G715 Page 10 Drain fill is the material placed in front of and/or beneath the reinforced soil matrix (select fill and geogrid reinforcements) to collect and drain the water accumulated behind blocks, and its gradation should be in compliance with the following criteria: Particle Size(U. S. Sieve) Passing By Weight(%) 1 inch 100 inch 75- 100 No. 4 0- 10 No. 40 0-5 No. 200 3 Max. Drain fill should be placed no more than 10 inches per lift in loose state, compacted with a vibratory compactor to a non-yielding condition. The keyway trench should be excavated to bearing soils with an allowable bearing capacity no less than 2,000 psf, and the wall installation should start immediately after completion of the keyway trench excavation. The soils exposed on the bottom of the keyway trench should be compacted to a non-yielding condition using a vibratory compactor, followed by the placement of a minimum of 6-inch-thick base course consisting of 5/8-inch crushed rock with the same compaction efforts. The drain fill should be placed at least 12 inches in thickness behind the wall up to the capping topsoil as shown on Figure 7. The first course of blocks should be set on the crushed rock base and have a toe embedment of at least 8 inches. Each course of blocks should be set back at a 1H:8V facing inclination with a level backslope and frontslope. A minimum 4-inch- diameter, rigid, perforated PVC pipe should be installed along the heel of the keyway trench. This drain pipe should have a proper gradient to generate flow by gravity, and the drainline should be tightlined to discharge to a designated stormwater drainage system. Due to the specific characteristics of each product (geogrids and corresponding concrete blocks), the design of a segmental block wall should follow the standards and specifications in the manufacturer's design manual. We recommend soil parameters (unit weight = 120 pcf, cohesion = 0, angle of internal PIONEER ENGINEERING,INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G715 Page 11 friction = 30°) be used in designing such a structure. A minimum factor of safety equal to 1.5 should be applied to the structural design against sliding and overturning failures. FLOORS The on-grade floor slab should be placed on firm, undisturbed native soils prepared as stated in the SITE GRADING AND EARTHWORK and ENGINEERED FILL AND COMPACTION sections of this report. For the unheated areas such as garages, storage rooms or tool sheds, the on- grade floor slab should be placed directly on a capillary break which is composed of a minimum 4-inch-thick layer of free-draining 5/8-inch crushed rock containing no more than 5 percent of fines by weight passing the U.S. No. 200 sieve. We recommend that a durable vapor retarder, a 6-mil (0.006 inch) plastic membrane, be placed over the capillary break to keep moisture from migrating upwards. For the heated areas, an additional layer of Styrofoam may be placed between the slab and capillary break for provision of better insulation. Where applicable, the ground surface in the crawl space (under-floor) should be free of vegetation, organic material, and construction debris. The exposed soils in the crawl space should be covered with a continuous vapor retarder with a maximum permeance rating of 1.0 perm in accordance with ASTM E96. The foundation wall should provide proper openings for the cross-space ventilation in the crawl space, if a mechanical ventilation system is not to be installed. PAVEMENTS Adequate preparedness would provide better bearing and drainage conditions of the pavement subgrade for a satisfactory installation. We recommend that a flexible pavement section be composed of 3 inches of Asphalt Concrete (AC) over 6 inches of Crushed Rock Base (CRB), or 3 inches of AC over 4 inches of Asphalt Treated Base (ATB). A rigid pavement section consisting of 5 inches of concrete over 5 inches of adequately compacted 2-inch-minus CRB may be used as an alternative. Perco-Crete or similar products may be used in the parking and driveway to reduce the impervious area. PIONEER ENGINEERING,INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G715 Page 12 UTILITIES The primary concern for utility trench backfilling is to prevent settlements along the alignments, particularly in paved areas. It is important that each section of the utility line be adequately supported by the bedding material. This material should be hand tamped to ensure support is provided around the pipe haunches. Engineered fill should be carefully placed and hand tamped to at least 12 inches above the crown of the pipe before any mechanical or vibratory compaction equipment is brought into use. The remainder of the trench backfill should be placed and compacted as stated in ENGINEERED FILL AND COMPACTION. DRAINAGE The finished ground around each building should be graded such that surface water is directed away from it. Water should not be allowed to stand within the building limits or in areas where foundations, on-grade slabs or pavements are to be constructed. We recommend that the ground be sloped at a minimum gradient of 3 percent for a distance of at least 10 feet away from the building except in paved areas. Storm runoff on the impervious surfaces (roof, paved driveway and parking, and deck) collected by downspouts and/or captured by catch basins should be tightlined to discharge to a stormwater drainage system. Roof downspout drainlines should not be connected to the footing drain system. Sufficient cleanouts should be installed at strategic locations to allow for regular maintenance of the footing system and downspout drainlines. A footing drain system should be installed along the perimeter of each building to prevent the buildup of hydrostatic pressure behind the foundation wall. This drainage system should consist of a 4-inch-diameter, rigid, perforated PVC pipe with its invert placed slightly below the bottom of the footing. The drain pipe should be wrapped with a layer of durable non-woven geotextile, bedded on at least 3 inches thick clean pea gravel (2-inch to 5/8-inch in size) and covered at least 6 inches of the same material. The drain pipe should have a sufficient gradient to generate flow by gravity. A dampproofing coating composed of a bituminous coating, or 3 pounds per square yard of acrylic modified cement, or 1/8-inch coating of surface-bonding mortar in compliance with ASTM C887, should be applied to the under-grade portion of the foundation wall. A typical footing drain system is illustrated on Figure 8. PIONEER ENGINEERING,INC. July 3,2007 Geotechnical Engineering Study PEI Project No.G7I5 Page 13 GEOLOGIC HAZARDS With the integrity of the underlying soil conditions and absence of a shallow, steady groundwater table, the risk of geologic hazards such as a landslide hazard, erosion hazard or seismic hazard at the site is practically negligible. ADDITIONAL FIELD SERVICES We recommend that PEI be retained to perform a general review of the final design and specifications of the proposed development, and to verify that our geotechnical recommendations have been properly interpreted and incorporated into the design plans and construction documents. We also recommend PEI be retained to provide monitoring services for geotechnical aspects of the construction work of this project. This is to observe compliance with the design concepts, specifications or recommendations and to allow for design changes in the event subsurface conditions differ from those anticipated prior to start of construction. Respectfully submitted, PIONEER ENGINEERING, INC. Joseph Wu, P.E. Consulting Geotechnical Engineer Attachments: Figure 1 -Vicinity Map Figure 2 - Site and Exploration Plan Figure 3- USCS Chart Figures 4 to 6 - Test Pit Logs Figure 7 -Typical Segmental Block Wall Figure 8 -Typical Footing Drain System PIONEER ENGINEERING, INC. t J I __ �'E 4 , ‘ ....3\sti i ! i 1 I .41 ‘) i _cii,' . s C ` LilIra i PROJECT ‘ :au:4111:110111111t SITE :1.,.J . ii1( -. Ail . 1.- ,, 1RDIL' 7///// ...,.. r...< [1,31P(__ ._, I' ' f � 7 ER -10-i 14 __..... ._._ 1 lit -_ f . 1 6.: . H Ll.....f ...K N ED VICINITY MAP PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering Earth Science Water Resources RENTON, WASHINGTON PROJ. NO. G715 DATE 6/29/07 FIGURE 1 'K: lY '`s ' \\ 4~`V f N00 3546'E 1062 +..51,15 dap.ea" bud TP-1 ---�. - ' -- s' a g. . ,. \� -__ -- ~ l ---0.-_,I /�— el \\\._._z_, TP-4 \\_"`*--- ��--- -- — —t_ ,q _TP-2v �__—__ ----TP-5 - .-, _ 01 ft _\ ----•••-.__ p••• tip" -nf • „ --1 TP- ; .�4R. - ,��. , _. r— r timet—` • TALBGT FID. .• _ . ---. L , EDz Scale: 1”=60' SITE AND TEST PIT LOCATIONS PLAN PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering • Earth Science . Water Resources RENTON, WASHINGTON PROJ. NO. G715 DATE 6/29/07 FIGURE 2 UNIFIED SOIL CLASSIFICATION SYSTEM MAIN DIVISIONS GROUP GROUP NAME SYMBOL GRAVEL CLEAN GW WELL-GRADED GRAVEL,FINE TO COARSE GRAVEL COARSE-GRAINED MORE THAN 50%OF GRAVEL GP POORLY-GRADED GRAVEL SOILS COARSE FRACTION RETAINED GRAVEL WITH GM SILTY GRAVEL ON THE NO.4 SIEVE FINES GC CLAYEY GRAVEL MORE THAN 50%RETAINED SAND CLEAN SW WELL-GRADED SAND,FINE TO COARSE SAND ON THE NO.200 SIEVE MORE THAN 50%OF SAND SP POORLY-GRADED SAND COARSE FRACTION PASSING SAND WITH SM SILTY SAND PASSING NO.4 SIEVE FINES SC CLAYEY SAND FINE-GRAINED SILT AND CLAY INORGANIC ML SILT,SANDY SILT SOILS LIQUID LIMIT LESS CL LEAN CLAY THAN 50% ORGANIC OL ORGANIC SILT,ORGANIC CLAY MORE THAN 50%PASSING SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY,ELASTIC SILT THE NO.200 SIEVE LIQUID LIMIT CH CLAY OF HIGH PLASTICITY, FAT CLAY 50%OR MORE ORGANIC OH ORGANIC SILT,ORGANIC CLAY HIGHLY ORGANIC SOILS PT PEAT NOTE: SOIL MOISTURE INDICATORS: 1. FIELD CLASSIFICATION BASED ON VISUAL EXAMINATION DRY-ABSENCE OF MOISTURE,DUSTY,DRY TO OF SOIL IN GENERAL ACCORDANCE WITH ASTM D2488. THE TOUCH. 2. SOIL CLASSIFICATION USING LABORATORY TESTS IS SLIGHTLY MOIST-TRACE MOISTURE,NOT DUSTY. BASED ON ASTM D2487. MOIST-DAMP,BUT NO VISUAL WATER. 3. DESCRIPTIONS OF SOIL DENSITY OR CONSISTENCY ARE VERY MOIST-VERY DAMP,MOISTURE FELT TO BASED ON INTERPRETATION OF BLOW-COUNT DATA, THE TOUCH. VISUAL APPEARANCE OF SOILS,AND/OR TEST DATA. WET-VISUAL FREE WATER OR SATURATED, USUALLY SOIL IS OBTAINED FROM BELOW WATER TABLE. USCS CHART PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering• Earth Science• Water Resources RENTON, WASHINGTON PROJ.NO. G715 DATE 6/29/07 FIGURE 3 TEST PIT NO. TP-1 Logged By: JW Date: 6/28/07 Ground Elev. 475.0' ± Depth Sam'le (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. 8"Landscaping topsoil and lawn grass. SM Brown, silty,fine SAND,trace coarse gravel, loose, moist. (FILL; SM Dark Brown,silty,fine SAND,organics,trace coarse gravel, loose. moist. (RELIC TOPSOIL?) _ SM Grayish brown,silty,fine to medium SAND,trace fine gravel 5 occasional cobble,some orange staining,medium-dense,moist. B 1 (ABLATION TILL) SM Grayish brown,silty,fine to medium SAND,trace fine gravel occasional cobble,slightly cemented,dense, moist. (LODGMENT TILL) 10 Test pit terminated @ 10 ft,no groundwater encountered during test pit excavation TEST PIT NO. TP-2 Logged By: JW Date: 6/28/07 Ground Elev. 480.0' ± Depth Sample (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. 12"Landscaping topsoil and lawn grass. SM Brown, silty,fine SAND,trace coarse gravel, loose, moist. (FILL SM Grayish brown,silty,fine to medium SAND,trace fine gravel occasional cobble, some orange staining,medium-dense,moist. (ABLATION TILL) 5 SM Grayish brown,silty,fine to medium SAND,trace fine gravel occasional cobble,slightly cemented,dense, moist. (LODGMENT TILL) Test pit terminated @ 6.5 ft, no groundwater encountered during test pit excavation LEGEND: SS-2"O.D.Split-Spoon Sample GROUNDWATER: Seal ST-3"O.D.Shelby-Tube Sample Water Level B - Bulk Sample ❑Observation Well Tip TEST PIT LOGS PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering Earth Science• Water Resource RENTON, WASHINGTON PROJ.NO. G715 DATE 6/29/07 FIGURE 4 TEST PIT NO. TP-3 Logged By: JW Date: 6/28/07 Ground Elev. 488.5' ± Depth Sample (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. 8"Landscaping topsoil and lawn grass. — SM Brown, silty,fine SAND,trace coarse gravel, loose, moist. (FILL; • SM Grayish brown,silty,fine to medium SAND,trace fine gravel occasional cobble,some orange staining,medium-dense, moist. (ABLATION TILL) SM Grayish brown,silty,fine to medium SAND,trace fine gravel 5 occasional cobble, slightly cemented, dense, moist. B 1 (LODGMENT TILL) Test pit terminated @ 6.5 ft, no groundwater encountered during test pit excavation TEST PIT NO. TP-4 Logged By: JW Date: 6/28/07 Ground Elev. 477.5' ± Depth Sample (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. cyo 12"Landscaping topsoil and lawn grass. — SM Brown, silty,fine SAND,trace coarse gravel, loose, moist. (FILL; SM Gray,silty,medium SAND,trace fine gravel, medium-dense moist. A_BLATION_TILL? SM Grayish brown,silty,fine to medium SAND,trace fine gravel occasional cobble, some orange staining,medium-dense, moist. 5 (ABLATION TILL) _ SM Grayish brown, silty,fine to medium SAND,trace fine gravel occasional cobble,slightly cemented,dense, moist. (LODGMENT TILL) -Some rock fragments @ 6 to 8 ft. 10 Test pit terminated @ 10 ft,light groundwater encountered @ 3 ft during test pit excavation LEGEND: SS-2"O.D.Split-Spoon Sample GROUNDWATER: 0 Seal ST-3"O.D.Shelby-Tube Sample Water Level B - Bulk Sample 0 Observation Well Tip TEST PIT LOGS PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering Earth Science Water Resource RENTON, WASHINGTON PROJ.NO. G715 DATE 6/29/07 FIGURE 5 TEST PIT NO. TP-5 Logged By: JW Date: 6/28/07 Ground Elev. 480.5' ± Depth Sample (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. 8"Landscaping topsoil and lawn grass. SM Brown,silty,fine SAND,trace coarse gravel, loose, moist. (FILL) SM Grayish brown,silty,fine to medium SAND,trace fine gravel, occasional cobble, some orange staining,medium-dense, moist. (ABLATION TILL) 5 SM Grayish brown, silty,fine to medium SAND,trace fine gravel, occasional cobble,slightly cemented,dense, moist. (LODGMENT TILL) -Some rock fragments @ 5 ft. Test pit terminated @ 6.5 ft, very-light groundwater encountered @ 3 ft during test pit excavation. TEST PIT NO. Logged By: Date: Ground Elev. Depth Sample (N) W USCS Soil Description Blows/ Other Test ft. Type No. ft. 5 10 LEGEND: SS-2"O.D.Split-Spoon Sample GROUNDWATER: Seal ST-3"O.D.Shelby-Tube Sample Water Level B - Bulk Sample El Observation Well Tip TEST PIT LOG PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering Earth Science• Water Resource RENTON, WASHINGTON PROJ.NO. G715 DATE 6/29/07 FIGURE 6 STANDARD BLOCK r FINISH GRADE I 1 18"MAX.TOPSOIL H COMPACTED 12"MIN. SELECT NON-WOVEN ON-SITE SOILS I• FILL GEOTEXTILE FINISH GRADE 1 X 4 GEOGRID 8"MIN. t 1�� • 6"MIN. r 5/8"CLEAN 7. DRAIN FILL CRUSHED ROCK 4"MIN.PERF.PVC PIPE WRAPPED WITH NON-WOVEN GEOTEXTILE NOT TO SCALE Notes: 1. The keyway trench of the segmental block wall shall be excavated to firm undisturbed native soils with a minimum allowable bearing capacity of 2,000 psf. 2.The installation of the block wall shall start immediately after completion of keyway trench excavation. 3. A minimum thickness of 6 inches of clean 5/8-inch crushed rock shall be placed over the adequately-compacted subgrade to form a leveling pad, and the rock be compacted to a stable condition with a vibratory compactor. 4. The block wall shall have a minimum toe embedment of 8 inches and each course of blocks be set back at a 1 H:8V or steeper facing inclination. 5. The wall shall be designed to have a minimum factor of safety equal to 1.5 against sliding and overturning failures. TYPICAL SEGMENTAL BLOCK WALL PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering • Earth Science • Water Resources RENTON, WASHINGTON PROJ. NO. G715 DATE 6/29/07 FIGURE 7 Foundation Wall Slope to Drain Dampproofing Coating Non-Woven Geotextile Engineered Fill • 6"Min. ir Slab 2"to 5/8"Clean Pea Gravel •' 4"-Diameter Min. Perforated,e orated, ___ Capillary Break PVC Drain Pipe with Positive 3"Min. Gradient to Discharge Not to Scale Notes: 1. Engineered fill should consist of clean,granular soils with individual particles no larger than 4 inches in size,and contain no organic and other deleterious substances. 2. Engineered fill should be placed in lifts no more than 10 inches thick in loose state,and be compacted within one percent of its optimal moisture content to attain the maximum dry density determined by ASTM D1557 (Modified Proctor Method). 3. The top 2 feet of engineered fill should be compacted to at least 95 percent of its optimal dry density,and 90 percent for the remaining area. 4. The capillary break should consist of a minimum 4-inch-thick layer of free-draining 5/8-inch crushed rock containing no more than 5 percent by weight passing the No.200 sieve. A 6-mil plastic membrane may be placed over the capillary break as a vapor retarder. 5. The dampproofing coating should consist of 3 pounds per square yard of acrylic modified cement, 1/8 inch coat of surface-bonding mortar in compliance with ASTM C 887. TYPICAL FOOTING DRAIN SYSTEM PIONEER ENGINEERING, INC. PROPOSED DUPLEX BUILDINGS 4701 TALBOT ROAD SOUTH Geotechnical Engineering• Earth Science• Water Resource RENTON, WASHINGTON PROJ. NO. G715 DATE 6/29/07 FIGURE 8 Hal Hagenson From: Scott, Mike [scottm@contech-cpi.com] Sent: Monday, January 31, 2011 10:48 AM To: h.hagenson@comcast.net Subject: FOLLOW UP ON YOUR INQUIRY FROM CONTECH CONSTRUCTION PRODUCTS Attachments: PDW-Stormwater Storage.docx Hal: Thanks for contacting us. I believe that we have talked before and provided information to you on some past projects. Regarding your current inquiry, here is a copy of your message and my comments (in red): I'm interested in using a 110" x 171"arch cmp for a stormwater detention tank. I was not able to find min cover requirements in your data. I'm assuming this would require 5X1 corrugations but if 3X1 is available I'd also like the min cover data for that as well. I'm interested in H2O traffic loads as it will be placed under a concrete paving section consisting of 7" of porous concrete on 9" gravel base (1.5 inch minus). Hal: The size you are calling out is not in our standard CMP design manual. However,we do make a 171" X 110" pipe arch (a 144" round pipe arched to those dimensions). That is the largest sized pipe arch in CMP that we make. For larger sizes we would recommend using plate structures if you need to use the pipe arch shape. From the NCSPA Corrugated Steel Pipe Design Manual and the Handbook of Steel Drainage and Highway Construction Products (Page 261 in the Green Book)we can obtain the Height-of-Cover Limits for pipe arch shapes. Please note that 171x110, in both 5x1 and 3x1 needs to be 10ga. Material. Minimum cover is 30" (you know the difference between asphalt and concrete when it comes to minimum cover—dimension should be from the top of pipe to the bottom of flexible pavement or to the top of rigid pavement). From the information in your message it doesn't appear that you would meet minimum cover requirements with the proposed design. Maximum cover is 19'. If you are trying to specify this it should be with 5X1 corrugations. This will cover H2O and H25 live loads. Please keep in mind that hauling this size pipe will require pilot cars, which will impact freight charges when considering costs delivered to the jobsite. We would need two pilot cars for this wide of load. For two pilots it is$180.00 out the door and $1.80 per mile. We will need more information regarding layout and fittings as well as risers, etc.to provide a cost estimate if you decide that this is what you want to use. We also should ask more questions regarding the application before making a recommendation. Please see the attached Project Design Worksheet and let us know more about the site conditions and application. We also would appreciate knowing a project name if possible. I would be happy to talk with you over the phone or meet with you to discuss this project in more detail. Just let me know. Thanks, Mike Scott project Consultant Field Marketing CONTECH Construction Products Inc. 19706 9th Place West I Lynnwood, WA 98036 Off: 425-835-0440 I Mob: 206-979-8732 I Fax: 425-835-0480 scottml(a�contech-cpi.com www.contech-cpi.com 1 fir HAGENSON PLO CONSULTANTS, LLC 6484—48th Ave.SW Seattle,WA 98136 Ph.(206)938-6168 Fax(206)938-7645 Email: H.Hagenson@comcast.net May 31,2011 Attention:Allen Quynn City of Renton 1055 South Grady Way Renton, WA Re: Talbot Road Townhomes, City No U100046 Dear Sir: We are writing to request a Stormwater Drainage Adjustment for the Subject Project. The Renton Surface Water Manual (Pg1-63) requires that runoff from multifamily projects must meet the enhanced basic water quality menu unless otherwise exempt. This Drainage Adjustment Application Letter is intended to request the City to allow the use of an enhanced water quality treatment exception specified in Section 1.2.8.1 (pg 1.-69) of the 2009 KCSWDM. The project is vested to the 2005 KCSWDM; however, the 2009 manual added an exception #4 in Core Requirement No. 8 which allows commercial projects to reduce the enhanced water quality treatment requirement to basic water quality treatment provided they meet the conditions therein. Per the 2009 KCSWM, section 1.2.8.1 (pg 1-69) Exceptions: 4. The Enhanced Basic WQ menu as specified above for treating runoff from a commercial land use may be reduced to the Basic WQ menu if all of the following criteria are met: a) No leachable metals(e.g., galvanized metals)are currently used or proposed to be used in areas of the site exposed to the weather,AND b)A covenant is recorded that prohibits future such use of leachable metals on the site(use the covenant in Reference Section 8-Q),AND c) Less than 50%of the runoff draining to the proposed treatment facility is from any area of the site comprised of one or both of the following land uses: •Commercial land use with an expected ADT of 100 or more vehicles per 1,000 square feet of gross building area. •Commercial land use involved with vehicle repair, maintenance, or sales. The project proposes no leachable metals exposed to weather (note potential galvanized metal storm drains must have treatment 1 asphalt lining inside and out). A covenant prohibiting leachable metals is included in section IX. None of the runoff draining to the proposed treatment facility is from a commercial land use (the site is multi-family) nor from a commercial land use involved with vehicular repair, maintenance or sales. Although the site is Mult-family, for traffic comparison purposes, ADT for the site is approximately 144 (based on 8 vehicles/day/home, ASSHTO Trip Generation Manual). The total square footage for each unit is approximately 2000 square feet, and there are 18 units so there is 144ADT/(2x18)=4 vehicles/1000 square feet of building area which meets the requirement. • Page 2 May 31,2011 The Drainage Adjustment Application Letter also requests the City to allow the use of a Stormfilter ZPG media cartridge basic water quality treatment facility as specified in Section 6.1.1 (pg 6-5) of the 2009 KCSWDM. Additionally, the Drainage Adjustment requests the City to allow the use of a CDS concentrator made by Contech®for use as pre-treatment for the proposed stormfilter ZPG media cartridge system The City indicated in prior conversations and 5/26/11 e-mail from Allen Quynn, Renton Project Manager, that they would consider these aforementioned adjustments provided the proponent can demonstrate that the project meets the requirements specified under Section 6.2 of the City of Renton Amendments to the 2009 King County Surface Water Design Manual which allows the City, through an adjustment process, to consider treatment facilities that have been given a general use designation through the Washington State Department of Ecology's Technical Assessment Protocol — Ecology (TAPE) program. The Department of Ecology has given CDS a general use designation for pretreatment (see appendix). The Drainage Adjustment Application to the Renton Development Services Division addresses the following: 1. Produces a compensating or comparable result that is in the public interest, AND 2. Meet the objective of safety, function, appearance, environmental protection and maintainability based on sound engineering judgment. Hagenson Consultants response to the above conditions is as follows: The proposed water quality system produces a compensating or comparable result that is in the public interest. The 2009 KCSWM includes water quality treatment methodology and technology that has evolved since the 2005 KCSWM. Projects with relatively low trip generation and automotive use (compared with high use retail sites) are now known to generate lower levels of heavy metals and other pollutants and are therefore eligible for exception from enhanced basic water quality requirements. The ZPG media cartridge system has been adopted by the 2009 KCSWM after extensive testing and has been accepted as demonstrating adequate performance to meet the Basic Water Quality Performance Goal of removal of 80% of TSS (total suspended solids) per 2009 KCSWM 6.1.1 (pg 6.4). The CDS concentrator made by Contech® for use as pre-treatment has been demonstrated to meet the KCSW pretreatment performance goal of 50% removal of TSS (2009 KCSWM 6.5.1, pg 6-103). This performance level is documented in "General Use Level Designation for Pretreatment (TSS) for Contech Construction Products, Inc. CDS System" (see Appendix). It should be noted that the CDS concentrator is approved for pretreatment use by the Washington State Department of Ecology to meet the requirements of their current stormwater manual. The proposed water quality system meets the objective of safety, function, appearance, environmental protection and maintainability based on sound engineering judgment. 1. Safety. The system consists of below grade manholes with standard accessibility and presents no greater safety dangers than comparable devices which are accepted under the current storwmater code. 2. Function. As addressed in the above discussion, the proposed system meets the treatment goals. 3. Appearance. Since the systems are below grade, they appear as manhole covers and do not differ from comparable accepted devices. • Page 3 May 31,2011 4. Environmental protection. Since their function is"environmental protection" and the proposed system meets the treatment goals, there is no reduction in environmental benefit. 5. Sound Engineering Judgment. The proposed system is accepted in either the 2009 KCSWM and/or the current Washington State DOE Stormwater Manual. We respectfully ask that the City issue the requested Drainage Adjustment. Sincerely, 4A-e.-ee2- kl-L7*"1A-'" Hal Hagenson, P.E. Hagenson Consultants, LLC Hal Hagenson From: Allen Quynn [aquynn@Rentonwa.gov] Sent: Thursday, May 26, 2011 1:07 PM To: 'Hal Hagenson' Subject: RE: Talbot Townhomes Hi Hal, I have reviewed your May 20, 2011 email to Hebe Berdardo requesting to use the CDS concentrator made by Contech® for use as pre-treatment for the proposed ZPG and CFS stormfilter cartridge system required for enhanced treatment on your project. Section 6.2 of the City Amendments to the 2009 King County Surface Water Design Manual allows the City, through an adjustment process,to consider treatment facilities that have been given a general use designation through the Washington State Department of Ecology's Technical Assessment Protocol—Ecology(TAPE) program. The Department of Ecology has given CDS a general use designation for pretreatment. To obtain approval,you must submit a written request for an adjustment to the Renton Development Services Division that address the following: 1. Produces a compensating or comparable result that is in the public interest, AND 2. Meet the objective of safety,function, appearance, environmental protection and maintainability based on sound engineering judgment. In your email,you had also requested the City consider granting you an adjustment to allow the use of an enhanced water quality treatment exception specified in Section 1.2.8 of the 2009 KCSWDM. The project is vested to the 2005 KCSWDM; however, as you pointed out,the 2009 manual added an exception#4 in Core Requirement No. 8 which allows commercial projects to reduce the enhanced water quality treatment requirement to basic water quality treatment. The City will consider the use of this exception provided you can demonstrate the project can meet the requirements specified under Exception No.4 in Section 1.2.8 of the 2009 KCSWDM. You can submit both adjustment requests as part of one request letter. Additional information on the adjustment processes can be found in Section 1.4 of the City amendments to the 2009 KCSWDM. Please feel free to email or call me if you have any questions. Allen Quynn, P.E. Project Manager City of Renton Surface Water Utility Engineer 425-430-7247 aquynn@rentonwa.gov From: Hal Hagenson jmailto:h.hagenson@comcast.netl Sent: Thursday, May 26, 2011 1:06 PM To: Allen Quynn Subject: FW: Talbot Townhomes Ha! Hagensor From: Hal Hagenson [mailto:h.hagenson©comcast.netl Sent: Thursday, May 26, 2011 1:05 PM 1 WASHINGTON STATE DEPARTMENT 0E ECOLOGY July 2008 (Update February 2010) (Updated to reinstate CONTECH CDS Oil Control PULD model name change) GENERAL USE LEVEL DESIGNATION FOR PRETREATMENT (TSS) AND PILOT USE LEVEL DESIGNATION FOR OIL CONTROL For CONTECH Construction Products Inc. CDS* System Ecology's Decision: Based on the CONTECH Construction Products Inc. (CONTECH)application submission for the CDS® System and recommendations by the Technical Review Committee(TRC),Ecology hereby issues the following use designations for the CDS technology: 1. General Use Level Designation (GULD)for pretreatment use, as defined in the Ecology Stormwater Management Manual for Western Washington Volume V,(a)ahead of infiltration treatment,or(b)to protect and extend the maintenance cycle of a basic or enhanced treatment device (e.g.,sand or media filter). This GULD applies to 2400 micron screen CDS®units sized per the table below at the Water Quality design flow rate as determined using the Western Washington Hydrology Model (WWFIM). The following table shows flowrates associated with various CDS models: Washington State System Sizing CDS Model ID Previous Model ID Flowrate (cfs) CDS 2015 PMIU20-15 0.7 CDS 2015-4 PMSU20-15 0.7 CDS 2015-5 PMSU20-15 0.7 CDS 2020 PMSU20-20 1.1 CDS2025 PMSU20-25 1.6 CDS3020 PMSU30-20 2 CDS3030 PMSU30-30 3 CDS4030 PMSU40-30 4.5 CDS4040 PMSU40-40 6 CDS3020-D PSWC30-20 2 CDS3030-D PSWC30-30 3 CDS3030-DV PSW30-30 3 CDS4030-D PSWC40-30 4.5 CDS4040-D PSWC40-40 6 CDS5042-DV PSW50-42 9 CDS5640-D PSWC56-40 9 CDS5050-V PSW50-50 11 CDS5653-D PSWC56-53 14 CDS5668-D PSWC56-68 19 CDS5678-D PSWC56-78 25 CDS7070-DV PSW70-70 26 CDS 10060-DV PSW 100-60 30 CDS 10080-DV PSW l 00-80 50 CDS100100-DV PSW100-100 64 *Specially designed CDSTM may be approved by Ecology on a site-by-site basis. 2. The pretreatment GULD has no expiration date, but it may be amended or revoked by Ecology. 3. Pilot Use Level Designation (PULD) for oil and grease treatment. This PULD applies to 2400 micron screen CDS® units sized per the table above at the water quality design flow rate as determined using the Western Washington Hydrology Model (WWHIM). 4. The oil and grease PULD expires September 1,2012 unless extended by Ecology. 5. All designations are subject to the conditions specified below. 6. Properly designed and operated CDS®systems may also have applicability in other situations(example: low-head situations such as bridges or ferry docks),for TSS and oil/grease removal where,on a case-by-case basis, it is found to be infeasible or impracticable to use any other approved practice. Jurisdictions covered under the Phase I or II municipal stormwater permits should use variance/exception procedures and criteria as required by their NPDES permit. 7. Ecology finds that the CDS®,sized according to the table above,could also provide water quality benefits in retrofit situations. Ecology's Conditions of Use: CDS®systems shall be designed,installed,operated and maintained to comply with these conditions: 1. CDS®Systems must be designed,assembled,installed,operated,and maintained in accordance with Contech's applicable manuals and documents and the Ecology decision and conditions specified herein. Ecology recommends the inspection and maintenance schedule included here: CDS Maintenance&Insped 2. Discharges from the CDS®System shall not cause or contribute to water quality standards violations in receiving waters. 3. On or before September 1,2010, Contech shall submit a QAPP that meets the TAPE requirements for attaining a GULD for oil treatment. 4. Contech shall complete all required testing and submit a TER on oil and grease removal for Ecology review by March 1,2012. 5. Contech may request Ecology to grant deadline or expiration date extensions,upon showing cause for such extensions. Applicant: CONTECH Construction Products, Inc.,Manufacturer and Vendor Applicant's Address: 11835 NE Glen Widing Drive Portland,OR 97220 Application Documents: • Contech Construction Products Inc.Application to: Washington State Department of Ecology Water Quality Program for General Use Level Designation—Pretreatment Applications and Conditional Use Level Designation—Oil Treatment of the Continuous Deflective Separation(CDSTM)Technology(June 2007) • Strynchuk, Royal, and England, "The Use of a CDS Unit for Sediment Control in Brevard County". • Walker,Allison, Wong, and Wootton, "Removal of Suspended Solids and Associated Pollutants by a CDS Gross Pollutant Trap", Cooperative Research Centre for Catchment Hydrology,Report 99/2, February 1999 • Allison, Walker,Chiew,O'Neill, McMahon, "From Roads to Rivers Gross Pollutant Removal from Urban Waterways", Cooperative Research Centre for Catchment Hydrology,Report 98/6,May 1998 Applicant's Use Level Request: General use level designation as a pretreatment device in accordance with Ecology's 2005 Stormwater Management Manual for Western Washington. Applicant's Performance Claims: Based on laboratory trials,the CDSTM System will achieve 50%removal of total suspended solids with d50 of 50-µm and 80%removal of total suspended solids with d50 of 125-µm at 100% design flow rate with influent concentrations near 200 mg/L. The CDSTM system equipped with standard oil baffle and the addition of oil sorbent is effective in the control of oil and can maintain the TPH level below 10 mg/L for applications in typical urban runoff pollution control. Technical Review Committee's Recommendation: The TRC fmds that: • The CDSTM system, sized per the table above, should provide, at a minimum, equivalent performance to a presettling basin as defined in the most recent Stormwater Management Manual for Western Washington, Volume V, Chapter 6. Findings of Fact: 1. Laboratory testing was completed on a CDS2020 unit equipped with a 2400 micron screen using OK-110 sand(d50 of 106-µm)at flowrates ranging from 1 to 125%of the design flowrate(1.1 cfs)with a target influent of 200 mg/L. Laboratory results for the OK-110 sand showed removal rates from about 65%to 99%removal with 80%removal occurring near 70%of the design flowrate. 2. Laboratory testing was completed on a CDS2020 unit equipped with a 2400 micron screen using"UF"sediment(d50 of 20 to 30-µm)at flowrates ranging from 1 to 125%of the design flowrate(1.1 cfs)with a target influent of 200 mg/L. Laboratory results for the"UF" sediment showed removal rates from about 42%to 94%removal with 80%removal occurring at 5%of the design flowrate. 3. Laboratory testing was completed on a CDS2020 unit equipped with a 4700 micron screen using OK-110 sand(d50 of 106-µm)at flowrates ranging from 1 to 125%of the design flowrate(1.1 cfs)with a target influent of 200 mg/L. Laboratory results for the OK-110 sand showed removal rates from about 45%to 99%removal with an average removal of 83.1%. 4. Laboratory testing was completed on a CDS2020 unit equipped with a 2400 micron screen using"UF"sediment(d50 of 20 to 30-µm)at flowrates ranging from 1 to 125%of the design flowrate(1.1 cfs)with a target influent of 200 mg/L. Laboratory results for the"UF" sediment showed removal rates from about 39%to 88%removal with an average removal of 56.1%. 5. Laboratory testing was completed on a CDS2020 unit using motor oil at flowrates ranging from 25%to 75%of the design flowrate(1.1 cfs)with influents ranging from 7 to 47 mg/L. Laboratory results showed removal rates from 27%to 92%removal. A spill test was also run at 10%of the design flowrate with an influent of 82,000 mg/L with an average percent capture of 94.5% 6. Various field studies were completed by independent parties in California,Florida, and Australia. Field studies showed the potential for the unit to remove oils and grease and total suspended solids, and gross solids. A spill test was also run at 10%design flowrate with an influent of 82,000 mg/L with an average percent capture of 94.5%. 7. CDS Technology has over 6,200 installations in the United States and Canada with over 1,380 installations in Washington and Oregon. Technology Description: A technology description can be downloaded from the company's website. Recommended Research and Development: Ecology encourages Contech to pursue continuous improvements to the CDSTM system.To that end,the following actions are recommended: 1. Conduct testing to quantify the flowrate at which resuspension occurs. 2. Conduct testing on various sized CDSTM units to verify the sizing technique is appropriate. 3. The system should be tested under normal operating conditions, such that the swirl concentrator is partially filled with pollutants. Results obtained for"clean"systems may not be representative of typical performance. Contact Information: Applicant Contact: Sean Darcy (800)548-4667 darcys@contech-cpi.com Applicant website: www.contechstormwater.com Ecology web link: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/index.html Ecology: Douglas Howie Water Quality Program (360)407-6444 douglas.howie@ecy.wa.gov