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LAROSA Technical Information Report February 11. 2014 Revised,April15.2014 Prepared for Conner Homes 846-108th Avenue NE. Suite 200 Bellevue. WA 98004 Submitted by ESM Consulting Engineers. LLC 33400 8'" Avenue S. Suite 205 Federal\'iay. YiA 98003 253.838.6113 tel 253.838.7104 fax www.esmcivil.com February 11, 2014 Revised: April 15, 2014 Approved By: City of Renton TECHNICAL INFORMATION REPORT FOR LAROSA Prepared for: Conner Homes 846-10811> Avenue NE, Suite 200 Bellewe, WA 98004 Prepared by: ESM Consulting Engineers 33400 811> Avenue S, Suite 205 FederalWay,WA 98003 Job No. 1670-004-013 Date TABLE OF CONTENTS 1. PROJECT OVERVIEW................................................................................................................................................................................. 1-1 2. CONDITIONS AND REQUIREMENTS SUMMARY .................................................................................................... 2-1 3. OFF-SITE ANALYSIS.................................................................................................................................................................................... 3-1 4. FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS AND DESIGN ............................. 4-1 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................................................. 5-1 6. SPECIAL REPORTS AND STUDIES........................................................................................................................................... 6-1 7. OTHER PERMITS............................................................................................................................................................................................ 7-1 8. CSWPPP ANALYSIS AND DESIGN............................................................................................................................................. 8-1 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT... 9-1 1 0. OPERATIONS AND MAINTENANCE MANUAL.......................................................................................................... 10-1 UST OF FIGURES 1.1 Vicinity Map 1.2 Existing Site Conditions 1.3 Proposed Site Conditions 1.4 Soils Map 3.1 KCGIS Parcel Reports/Environmental Hazards 3.2 Offsite Analysis Downstream Flowpath 4.1 Pond Predeveloped/Developed Tributary Areas Appendix A: Appendix B: Appendix C: Appendix 0: Appendix E: Appendix F: APPENDIX KCRTS Pond Sizing Output Geotech Reports prepared by Earth Solutions NW Conveyance Analysis Operations and Maintenance Manual Bond Quantity Worksheet/Declaration of Covenant/Facility Summary StormFilter Manhole and StormGate Calculations and Worksheets 1. PROJECT OVERVIEW The proposed L.aRosa Project is a 21-lot plat located between S 27'h Street and S 29th Street in the City of Renton, WA The project is 4.15 acres in size and incorporates four parcels numbered 008700-0070, 008700-0075, 008700-0080, and 008700-0081, all of which are zoned R-8. See Figure 1.1 for the Vicinity Map. The existing site consists of two single-family dwellings with gravel driveways and a few small structures. All structures on site will be demolished. The existing site is relatively flat (mean slope of about 7%, 10% max slopes on site) and slopes down generally from the southeast comer of the property towards the northwest. The pervious portions of the parcels are generally lawn except the northwest corner of the site, which is forested. See Figure 1.2 for the Existing Site Conditions. The proposed 4.15 acre project site consists of 21 residential lots and one storm drainage tract All 21 residential lots will have new single-family dwelling units. The project is zoned R-8 and the lots will be 4,500 SF minimum. For access, the project will construct a road through the project, extending S 281h Street (on the east side of the project) to a new intersection at Benson Road S. See Figure 1.3 for the Proposed Site Conditions. The stormwater detention will be provided with a detention pond in the storm facility tract located in the northwest corner of the site. Water quality will be provided with a StormFilter Manhole, following the detention pond. The detention pond/StormFllter will discharge to the northwest to an existing large roadside ditch in Benson Road S in the project frontage. See Section 3 for the Level 1 Downstream Analysis. According to the Geotech Report by Earth Solutions NW, the soils on site are predominantly native weathered and unweathered glacial till deposits. See Figure 1.4 for the Soils Map. Based on the City of Renton's Flow Control Application Map, the project site is in the Flow Control Duration Standard (Forested Conditions) area The site requires basic water quality treatment. The project will be subject to Full Drainage Review per the City of Renton 2009 Surface Water Design Manual Amendments and the 2009 King County Surface Water Design Manual (2009 KCSWDM). The City of Renton 2009 Surface Water Design Manual Amendment and the 2009 KCSWDM will collectively be referred to as the "2009 Surface Water Design Manual". 1-1 KING COUNTY. WASHINGTON. SURFACE WATFR DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR} WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner Conner Homes Phone ___________ _ Address 846-108th Ave NE, Suite 200 Bellevue, WA 98004 Project Engineer Brianne Gast field, PE Company ESM Consulting Engineers Phone 253 -83 8 -6113 Part 3 TYPE OF PERMIT APPLICATION • Landuse Services <Subdivisoo I Short Subd. I UPD D Building Services MIF I Commerical I SFR D Clearing and Grading D Right-of-Way Use D Other Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review Cl:bill) I Targeted (circle): Large Site Date (include revision dates): Date of Final: NIA Part 6 ADJUSTMENT APPROVALS I Part 2 PROJECT LOCATION AND DESCRIPTION Project Name _L_a_R_o_s_a ______ _ ODES Permit# _________ _ Location Township _2_3N ___ _ Range _s_E _____ _ Section 29 -'------- SiteAddress 2724 Benson Road S Renton, WA 98055 Part 4 OTHER REVIEWS AND PERMITS D DFWHPA 0 COE404 D DOE Dam Safety D FEMA Floodplain D COE Wetlands D Other __ _ D Shoreline Management • Structural ~aultl __ D ESA Section 7 Site Improvement Plan (Engr. Plans) Type (circle one): @1 Modified Small Site I Date (include revision dates): Date of Final: N/A Type (circle one): Standard I Complex I Preapplication / Experimental I Blanket Description: (include conditions in TIR Section 2) N/A Date of Annroval: 2009 Surface Water Design Manual 2 l/9/2009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yest@ Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : ~S~o~o~s~C~r~e~e~k _______ _ Special District Overlays:------------------------ Drainage Basin: Black River Stormwater RequirementsFlow Control Duration Standard (Forested) /Basic W( Part 9 ONSITE AND ADJACENT SENSITIVE AREAS D River/Stream ________ _ D Steep Slope ---------D Lake 0 Erosion Hazard _______ _ D Wetlands __________ _ D Landslide Hazard ______ _ D Closed Depression --------D Coal Mine Hazard ______ _ 0 Floodplain -----------D Seismic Hazard _______ _ 0 Other ___________ _ D Habitat Protection ______ _ D __________ _ Part 10 SOILS Soil Type Slopes Erosion Potential Alderwood 6% to 15% D High Groundwater Table (within 5 feet) D Sole Source Aquifer D Other D Seeps/Springs D Additional Sheets Attached 2009 Surface Water Design Manual 3 1/9/2009 KING COUNTY, WASl-IINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION I SITE CONSTRAINT a Core 2 -Offsite Anal~sis D Sensitive/Critical Areas D SEPA D Other D D Additional Sheets Attached Part 12 TIR SUMMARY SHEET lnrovide one TIR Summarv Sheet oer Threshold Discharoe Area) Threshold Discharge Area: (name or descriotion) Existing Roadside Ditch Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 1 Offsite Analysis Level: (2)1213 dated: September 19, 2013 Flow Control Level: 1 /CJ) I 3 or Exemption Number (incl. facility summary sheet) Small Site BMPs Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor:John Peterson Contact Phone: 425-646 -9280 After Hours Phone: Maintenance and Operation Responsibility: Private I( Public) If Private, Maintenance Loo Reauired: Yes I No Financial Guarantees and Provided: Yes I <r:I9) Liabilitv Water Oual ity Type: u:iasic)/ Sens. Lake / Enhanced Basicm I Bog (include facility summary sheet) or Exemption No. Landscape Manaqement Plan: Yes I No Soecial Reauirements {as annlicablel Area Specific Drainage Type: CDA I SDO I MDP I BP I LMP I Shared Fae. I None Reauirements Name: Floodplain/Floodway Delineation Type: Major I Minor I Exemption I ~ 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: N/A Source Control Describe land use: N / A (comm.lindustrial landuse) Describe any structural controls: 2009 Surface Water Design Mauual 4 1/912009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site: Yes Ui£_) Treatment BMP: Maintenance Agreement: Yes Kl'§:) with whom? Other Drainaae Structures Describe:stormFilter Manhole willb e used for Water Quality following detention. A Stormgate flow splitting structure will be used to route hiqh flows around the StormFilter. Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION • Clearing Limits • Stabilize Exposed Surfaces • Cover Measures • Remove and Restore Temporary ESC Facilities • Perimeter Protection • Clean and Remove All Silt and Debris, Ensure • Traffic Area Stabilization Operation of Permanent Facilities • Sediment Retention • Flag Limits of SAO and open space • Surface Water Collection preservation areas D Other D Dewatering Control • Dust Control • Flow Control Part 14 STORMWATER FACILITY DESCRIPTIONS /Note: Include Facilitv Summarv and Sketch) Flow Control T"ne/Descriotion Water Qualitv T"ne/Descriotion • Detention Basic/Pond D Biofiltration D Infiltration D Wetpool D Regional Facility • Media Filtration 3asic/StormFilter D Shared Facility D Oil Control D Flow Control D Spill Control BMPs D Flow Control BMPs D Other D Other 2009 Surface Water Design Manual 5 1/9/2009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS II Drainage Easement l:J Cast in Place Vault Iii Covenant l:J Retaining Wall l:J Native Growth Protection Covenant • Rockery > 4' High II Tract l:J Structural on Steep Slope l:J Other l:J Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorpor~t into this worksheet and the attached Technical Information Report. To the best of my knowtedg e information provided e is accwate , ---',{(_, . ' Lh /_~I'--· 2009 Surface Water Design Manual 1/9/2009 6 S 1881H ST S 27TH ST S 1881H ST Figure 1.1 Vicinity Map 1-2 n Figure 1.2 Existing Site Conditions 1-3 f'Lf~AW ~iH jiH r? ,., 1 ·' ~ rH I c.. ~ ~" ~" 0 -::' ~ .. , ~ CD '-St~~; ~ H~rn (1l {l m 0 ~ ~ \ ~ ~; I ' 0 -• ~ ;~q; e; I h,-, -" 0 d-,~ • _. ; ~H - "' ' "! 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C C• ,, ~~ 0 o: 0 ~ . (, -, ,' / r- "'' t. ,-, m ::: ~ ;'~ \ .. .'::'' ~. I ,/- 1_-7··,:, I -,-le'. . ,' ,.,,~· --I ' ' ! \ '_.. I 11 / I 111 ,, !11 ;I I,, ,, ,, " " '' <"<•1 if i y / . / / ,. -, ,C,1J m> cl ;o ,,('") /, ', ', C •, " " 0 _, u f-'k<).1::.. T 'JMJ( LaRosa \I iC r:::_r\J;:\ HILL':?, 2,S'JS.',7 / J_ ---I -, 71·1 0 '2 I; .J __ 1--u ,, ,, o, m 0 ,~· N 0 0 m / i~';~· " 1,, g~ ~; G In• R ,, ,- -< ; I /,_,; :;f_i __ ; ', I -~· / ;' ' : 1 , ·'I .,., . ' , "3, 0 ,o, ru > .. '-'G g~ ci> J 0 :f ~ 'o ru ,, I~ 1u, \r "'1··' ,o ,, ' ('I), " 00 .c~~ ,o " ,---- ! I I, k h ·~ I'" 'O n ,,, ,, 0 1, ,, I ii,/ -1r ,, I ,, ' ,, I I' 1 I ~--:--1 I I 1 I ~ ! : : ~ ~ ~ f i~ I :.:---I 11 ;,,. l!I 11 '!' ,·Y:"" r·-- ""'' / Ji, /r;t.' ., ., » ~ ~· s"'' ~ ~-,,I ,,, I ., :: (/) N 'l ! -; i~ ,, -g .> 0 '~' X m s>J r: 6 \' i;:¢· Ill 9 ~ ,;:.1 8 ,,; ,!': S C 0 ~l ~ ~ ~ ~ ; ~ g t : ! ; l !, ~ j c" ,~. ,", ~ J ' ' ' *0{199:r;)~ ' ' l), I '' 0 I i ~ C --, ,-,- ~ ·u i t-=, ' ~G r 1,m I G) m z 0 '~I T =: :n ? 0 m 0 ,o :; ,_- c ;s , 0 0 " m ~ '': ~ '" g '" ,, C 8 ;:=', ,,r ci > C o r ;o !1.1 z -~ ' rn -~ , < 0 > I "' r : q II ; g 'iJ Fi ,.f j,j \.~ ~ ,-, a ,., ,, 1i h t ~ r- (/) N ::: :r ~ JJ m m -; a ~ ~ 8 ' " ,, ~ ,., _;J :.::;: l'l ,~· 7 ~i - \) lti jT -, ? " I ::i )> ~ JJ -I 0 z 0 -n i m z ~ '" 0 -n (/) m g 0 z Jll ~ :n I\) "' z JJ Gl !11 "' m ,s z Gl 8 C z -~ ~ )> Figure 1.3 Proposed Site Conditions 1-5 \ \ \ ', "' ~-"' ~-I ' •. -, ' $~ ''"'--"'.s-o,,·. "' I I ru,.,,o-;, • V -9. <,,,,,, o...,o .s-, // ,/ A PORTION OF THE NW 1/4 OF SECTION 29, TWP. 23 N., RGE. 5 E, KING COUNTY, WA - S 27TH STREET r~cSlO[NTIAL ACC[S'i) Tf, I -.T, 21) -',. ~ --' '," I ,~'·-: , I I / /1 / \\\ \\_ \ rl!!il' , .. --.._ ():IST11,1G STPUCIUC'f TO !3[ ;;>EMOVEC 6 26' PPIVIIE AC:ESS f"ASOAENT 13 -\!.L 12 14 I I /~ORT~~--li~~ ALLEY I I ,-- \ I I 9 I I S ~~~~,.,~~~,~iT L-- I'· __ _ fc'ct ,o I ~I~- -1 = / rr\r ~, I I I 10 -\ \I , ' ffl I __,., -\ , _JI I~ . m:, ~-I I ii\'~ 11 C::\, ~~ 15 \ \ \ / ' /·--------. ; 1·~-'', -'- -~. ~· n SCALE: 1" • 40' r-..--· -__ """"'l 40 20 0 ~0 BO LEGEND CONTOUR INTERVAL,.. 1' t XISIII-IC SIORM DRMJAGE fXISIIW; C.:MJIIAPY '.-itWFP [X1Sllt·IG WA'"I'/ MAll'i ---SP--t~ FROPOSi::C-12"" SViPM CP/\1'·1/\C[ ----8-----PROPOSED &'"t S/\i11~t.P, SEWEP ----•----1-'POPJSEc-6-t WA-EP M/\111 • FIRE hYDPANl * STREET LIGHT PPOP05ED i_(ll I IIJf eu1,_D1tJG SETBACK LIIJ[ R~v,s1CNC, .. o.locsc•,M,c,N,'D"' I ;y I-, --- 0 -c;, i * ·-w ... ,. ~~ ~~ z• wf:r.., ~g zoo• -< '::; ~~ d $~ z8~ ~'i "" m (/) w :::i: 0 I a: w z z 0 0 E 0 ~ ·, ·a E • • " -~ n J''"' ~ ti ju' § z S' ~ z <x: ~ CJ) '?:. 0 i=! a: ::, <! : _J c§ "' ~ w ~ ~ 0 Sc " jt)[l ~o., "b:·s'-,c,,-~·.; ,'l'-C~ ~WC, NAM' J[Sl(;e<U\ ~y BIJG ~<,WN B'a cP ~H[CK(c' 9Y ~' 1C125/2UlJ DAH er --- PR,,JT FIG 1.3 1 ::JF 1 C,HCfT", Figure 1.4 Solls Map 1-7 - 47" 27 22' N § ill "' )<l ~ ; ! ; ; m 47" 27 13" N u, 3 "' ~ ~ 3 "' ~ 560140 560180 560220 560260 560140 560180 560220 560260 Map Scale: 1: 1,8 10 if printed on A landscape (11" x 8.5") sheet Custom Soil Resource Report Soil Map 560300 560340 560300 560340 ----=====--------c::========Melers 0 25 50 100 150 o--·so==1=ioo----·2icoo====:::i300Feet Map projectioo: Web Mercata-Comer coordinates: WGS84 Edge tics: IJTM Zone lON WGS84 ~ N ~ A 8 560380 560420 560460 560500 560380 560420 560460 560500 3 ~ :: ~ 3 ~ -;... ~ § ~ )sl ~ ! ~ ~ I s! 47" 27 2Z'N ~ 47" 2713"N Custom Soil Resource Report Map Unit Legend King County Area, Washington (WA633) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgC Alderwood gravelly sandy loam, 6.8 ' 6 to 15 percent slopes ---------------------- Totals for Area of Interest 6.8 ------------------ Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components_ They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements_ The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. 10 100.0% 100.0% 2. CONDITIONS AND REQUIREMENTS SUMMARY Review of the 8 Core Requirements and 6 Special Requirements This section describes how the project will meet the 2009 Surface Water Design Manual's Core and Special Requirements. Core Requirement No. 1 Discharge at the Natural Location In the existing conditions, the site drains to the west, towards a roadside ditch and culvert system on the east side of Benson Road S. The ditch and culvert system ultimately discharges to the northwest corner of the project site, and continues along Benson Road S. The proposed detention/water quality pond will discharge to the northwest corner of the site, which is the natural discharge location for the project site. Core Requirement No. 2 Off-site Analysis A Level 1 Downstream Analysis was performed by ESM on September 19, 2013. See Section 3 for the offsite analysis. Core Requirement No. 3 Flow Control Based on the City of Renton's Row Control Application Map, the project site is in the Row Control Duration Standard (Forested Conditions) area. See Section 4 for Flow Control Analysis and Calculations. Core Requirement No. 4 Conveyance System The stormwater drainage conveyance system will be sized to convey the 25 year design storm event and to contain the 100 year design storm event. A detailed Conveyance System Analysis and Design is provided in Section 5 and Appendix C. Core Requirement No. 5 Erosion and Sediment Control The proposed project will include clearing and grading for the 21 single-family units, associated roadways, and pond area. The two existing units and their associated driveways and accessory structures will be demolished. Erosion and sediment controls will be provided to prevent, to the maximum extent possible, the transport of sediment from the project site to downstream drainage facilities, water resources, and adjacent properties. The Temporary Erosion and Sedimentation Control (TESC) Plans will be shown on the final construction plans and additional information is provided in Section 8 of th is report Core Requirement No. 6 Maintenance and Operations The Operations and Maintenance Manual is provided in Appendix D. Core Requirement No. 7 Financial Guarantees and Uablllty All drainage facilities constructed or modified for projects will comply with the financial guarantee requirements as provided in the City of Renton Bond Quantities Worksheet. The Bond Quantities Worksheet, Declaration of Covenant, and Facility Summaries are provided in Section 9 and Appendix E. Core Requirement No. 8 Water Quality The site does not meet the requirements for enhanced treatment in the 2009 Surface Water Design manual, therefore Basic Water Quality treatment will be provided. Treatment for the pollution generating surfaces will be provided by a StormFilter manhole following the detention pond. See Section 4 for more information. 2-1 Special Requirement No. 1 Other Adopted Area-Specific Requirements There are no master drainage plans, basin plans, salmon conservation plans, stormwater compliance plans, flood hazard reduction plan updates, or shared facility drainage plans for this project. Special Requirement No. 1 does not apply. Special Requirement No. 2 Flood Hazard Area Delineation There is no 100-year flood plain associated with a large body of water (i.e. lake or stream) on the site or adjacent to the site. Special Requirement No. 2 does not apply. Special Requirement No. 3 Flood Protection Facilities The project lies outside any pre-defined flood plain. Special Requirement No. 3 does not apply. Special Requirement No. 4 Source Control The project is a residential subdivision and is not subject to this requirement. Special Requirement No. 4 does not apply. Special Requirement No. 5 Oil Control The project does not have a "high-use site characteristic" and is not a redevelopment of a high-use site. Special Requirement No. 5 does not apply. Special Requirement No. 6 Aquifer Protection Area According to the "Groundwater Protection Areas in the City of Renton" map, the project site is not in an Aquifer Protection Area. Special Requirement No. 6 does not apply. 2-2 3. OFF-SITE ANALYSIS Task 1: Study Area Definition and Maps Figure 1.2 shows the existing site conditions. Figure 3.2 shows the extent of offsite analysis and the downstream flow path from the site. Task 2: Resource Review • Flow Control Map According to the City of Renton Flow Control Application Map, the site is in a Flow Control Duration Standard (Forested Conditions) area. • Soil Survey Map According to the Geotech Report prepared by Earth Solutions NW on September 10, 2013, the geologic map of the area indicates the site is underlain by glacial till (Qvt) deposits throughout the site. The native soils observed at the test pit locations are generally consistent with glacial till. • King County iMap According to the King County GIS Viewer (iMap), the project is NOT in any of the following areas: o Streams & 100 year floodplains o Erosion Hazard Areas o Seismic Hazard Areas o Landslide Hazard Areas o Wetlands According to Figure 4-3-050Q3a(i) in the Renton Municipal Code, a portion of the north parcel is located in a moderate Coal Mine Hazard Area. However, Earth Solutions NW, LLC has evaluated the site and determined that there is no evidence of a coal mine hazard area on site. Please see Earth Solutions' report in Appendix B. • City of Renton 2009 Surface Water Manual Amendments There are "sensitive" slopes onsite in the northwest comer of the property, however this area will be re-graded to be below 25%. According to the Reference 11 in the City of Renton 2009 Surface Water Design Manual Amendments, the project is NOT in any of the following areas: o Aquifer Protection Areas o Groundwater Protection Areas • Road Drainage Problems None noted • Wetlands Inventory There are no recorded wetlands on or near the site. • Migrating River Study None noted 3-1 City of Renton Coal Mine Hazard 11 ~====:;o;::::::=========================.i:-==============~ ~ ~ '<t (:, 0 0 0 2640 !~ ~ : Not es None 11 34 1307 0 0 67 WGS_ 1984_ Web_Mercator_Auxiliary_Sphere 1405 134 Feet City of Renton {) Finance & IT Div is io n 1409 1417i 1~13 Legend City and Co unty Boundar y Other [: J City of Renton Addresses P a r ce ls Coalmine HIGH D MODERATE UNCLASSIFIED ?' P r i m::irv I nfo rmatio n Tec hno l ogy · GIS RentonM apSupport@Re ntonwa .gov 4/15/2 0 14 1505 1 511 1517 1523 160 1 1607 Th s rnao 1s a user generated static output from an Internet mappings te and' ,s for reference only Data layers tha t appear on lh1s map may oi may riot be accurale, current, 01 other1.·1se rebable T HIS MAP IS NOT TO BE USED FOR NAVIGATION City of Renton Regulated Slopes N o t es I I None II 0 111 34 0 67 134 Feet WGS _ 1984_ Web _Mercato r_ Au xiliary_ Sphere City of Rento fl {) Finance & IT Division Leg end City a nd Co u nty Bou ndary Other r:J City of Renton Addresse s Parcels Slo pe City of Renton ">15% & <=25% >25% & <=40% (Se nsitive ) • >4 0% & <=90% (Protected) a >90% (Protected) Informati o n Technology -G IS RentonMapSupport@Rentonwa.gov 4/15/2014 This map 1s a use r generated siatic output fr om an Internet mapp.ng site and 1s for reference 0·1ly. Da:a layers t hat appea' on this map may or may net be accurate cu rrent. or olherwise reliable THIS M AP IS N OT TO BE US ED FO R NAVIGATI ON d Landslide, N otes . Aquifer. Eros ion , Fl:s 'Wetlands Sensitive Areas . t d Shoreli ne , Strea , Se ismic, REg ula e 11 0 67 II O . Sphe~ 134 tor Auxiliary_ Web Merca -WGS_1984_ - L egend ty Boundary City and Coun Other :-· ! City of Renton l ,J Add resses Parcels . ones ·rer Protection Z Aqu 1 D Z one 1 Zone 1 M odified D E rosion v;;i Fl oodway d A reas (100 1&.1 d Hazar D Special Floo yea r flood) Landslide • VERYHIGH • HIGH • MODERAT E UNCLAS SIFED Figure 3 .1 KCGIS Parcel Report/Environmental Hazards 3-2 ~ King County King County D is tricts and D evelopment Conditions for parcel 0087000080 Black River v-,. ,J Parcel number 0087000080 Drainage Basi n Address 16424 BENSON RDS ~ Jurisdiction Ren ton -Zipcode 98055 PLSS NW -29 -23 -5 ~ Kroll Map page 601 L atitude 47.45546 ' Thomas Guide page 656 Longitude -122.20133 Electoral Districts Congressional district Legislative d istrict RNT 11-1 012 District 5 , (206) 296-1005 9 • Fire district Water distric t Sewer district Water & Sewer district does not apply does not apply does not apply Soos Creek Wate r & Sewer District Park s & Recreation d istrict does not apply School district Hospital district Public Hospital District No. 1 Rural King County Library System No Seattle school board district d oes not apply (not in Seattle) Rural li brary district District C ourt elec tora l district Southe ast Tri bal L ands? King Countypla nning and designat ions NA, check with jurisdiction No ne does not apply Urban does n ot apply Soos C reek Yes Fores t Production district? Ag ri cultu ra l Production district? Coal mine h azard s? Erosion hazards? Landslide hazards? Seismic hazards? None mapped None mapped None mapped 100-year flood pla in? Wetlands at th is parcel? ? do es not apply 333 does not apply No No No None mapped None mapped None mapped This report was generated on 9/2712013 3 :12:02 PM C ontact us at ©2010 King County lQ King County Ki ng County D is tricts and D ev elo pme nt Co ndition s for pa rcel 00 8 7000081 Parcel number 0087000081 Dra inage Basin Address Not Avai lab le Jurisd iction Renton -Zipcode 98055 PLSS Kroll Map page 601 Latitude Thomas Guide page 656 Longitude 'ff Electoral Di stri cts RN T 11-1 0 12 District 5, (2 06) 296·1 005 Black River NW-29-23 -5 47.45552 -122.19947 F ire d istrict Wa ter d istrict Sewer dist r ict d oes no t apply does not appl y does not apply "' Congressional district Legislative district School district 9 Water & Sewe r district Soos C reek W at er & S ewer Dist ric t • Pa rks & R ecr eation district d oe s not apply Hospita l d istrict Sea ttle school board district does no t apply (not in Seattle) Rural library d istrict Public Ho spital D istrict No . 1 Rura l King County Library System No District Court electoral district So utheast T rib al La nds? Ki ng County plan ni ng and designations Coal mine hazards? Erosion hazards? L andslide hazard s? Seismic hazard s? NA, check w ith jurisdictio n None does not appl y Urban d oes not apply Soos Creek N o ne m apped None mapped None m apped N one mapp ed Forest Production district? Ag ricu ltura l Production district? 100·year flood plain? Wetlands a t this parcel? does not appl y 333 does not apply No No No N one map ped None map ped None map ped This report was genera ted on 9/27/2013 3:13:23 PM Contact us a t © 20 10 King County l4 King County King County Districts and Development Conditions for parcel 0087000075 ----------- Parcel number Addre ss Ju risdiction Zipcode 0087000075 Drainage Bas in Black River 2724 BENSON RD S Renton -98055 Kroll Map page 601 Thomas Guide page 656 E Electora l Districts Congressional district Legislative district PLSS Latitude Longitude RNT 11-1012 District 5 , (206) 296-1005 9 • NW-29 -23 -5 47.45516 -122.20074 Fire district Water district Sewer district Water & Sewer d istrict doe s not apply does not apply does not apply Soos Creek Water & Sewer District Park s & Recreation d ist ric t does not apply School district Hospital district Public Hospital District No. 1 Rural King County Library System No Seattle school board district does not apply (not in Seattle) R ura l li brary district District Court electoral d istrict Southeast Triba l Lands? Kin_g County plann ing_ and designations NA , check w ith jurisdiction None does not apply Urban does not apply Soos Creek None mapped None mapped None mapped None mapped Forest Production district? Agricu ltural Production district? Coal mine hazard s? Erosion hazards? Landslide hazards? Seismic hazards? 100-year flood plain? We tl ands at this pa rcel? ? does not apply 333 does not apply No No No None mapped None mapped None mapped This report was generated on 9/27/2013 3:45:35 PM Contact us at © 2010 King County b King County King Coun ty Di stricts and Development Cond itions for parcel 0087000070 Parcel number 00870 000 70 Drainage Basin Black River Address Not Ava ilable Jurisdiction Renton Zipcode 98055 Kroll Map page 601 T homas Guide page 656 f' Electoral District s Congressional district Legisla tive district School district -P LSS Latitude Longitude RNT 11-101 2 District 5 , (206) 296-1005 9 • NW-29 · 23 • 5 47.45485 -122.20002 Fire district Water district Sewer district Water & Sewer district does not apply does not apply does not apply Soos Creek W ate r & Sewer Distric t Parks & Recreation district does not apply Hospital district Seattle schoo l board d is trict does not apply (not in Seattle) Rural library district Public Hospital District No. 1 Rural King County Library System No District Court electoral district So utheast Triba l Lands? '=-Kil}_g County planning an_sl desig natio.i:is Coal mine hazards? Erosion hazards ? Landslide h aza rds? Seismic hazards? NA, check with jurisdiction None does not apply Urban does not ap ply Soos Creek None mapped None m a pped None mapped None mapped Forest Production d istrict? Agricultu ra l Production district? 100-year fiood plain? Wetlands at this parcel? ? does not apply 333 does not apply No No No None mapped None mapped None mapped T his report was generated on 9/27/2013 3:15 :49 PM Co ntact us a t © 2010 King County Downstream Drainage Complaints There are no downstream drainage complaints w it h in the last 10 years. Th e on ly drainag e complaint in the downstream path is number is 2001-0026 and is on parcel #2923059105. It is a request for drainage info rmati on, and was c losed on 2001-01-26. Rec Complaint Proble Typ e Recd Close Address PIN Comments No m Date Date 1 2001-0026 DDM C 1/11 /2001 1/26/2001 1641 5 292305910 REQU EST FOR INFORMATION OF EX BENSON 5 DRAI N GE ACROSS PVT PROP. RD SYST EM APPEARS TO BE C ITY OF RE NTON . This does n ot pertain to fl ood ing or any drainage system problem ; therefo re the project s ite would not impact any d ownstream drai nage complaints. 3 -7 Task 3: Field Inspection (Level 1 Inspection) A Level 1 Downstream Analysis was completed by ESM Consulting Engineers on September 19, 2013. The pro ject sits at the t op of th e Ro ll ing Hills Su bbasin. The project site is at a h igh point, and very little flow is anticipated to flow o n site. A portion of th e road to the east (S 281h St.) will flow onto the project site o n the road. This area will be conveyed through the pro posed detention /water quality pond. There is a portion of t he uphill frontage road th at naturall y drains through the project's existing frontage . This area will be collected and detained and treated in the proposed dete ntion/water quality pond. Task 4: Drainage Description and Problem Descriptions According to iMap, the entire project si te is in the Black Ri ver (King County WRIA #9) basin. Black River is located to the northwest of the project s ite, and is tributary to the Duwamish Waterway. In general, th e si te fl ows fr o m th e south east to the northwest. The low point of the s ite is in the northwest corne r of th e property, and d ischarges to an ex is ting roadside d itc h to the north along the east side of Benson Road S. From here th e fl ow continues north for about 140 feet un t il it enters a Type 2 catc h bas in via a c ulvert in the roadside ditc h. Th e catc h basin flows to the north through a series of catc h basin s with solid lid s located in the planter st rip parallel to Benson Road S. It appears to enter a Type 2 catch basin located at the e nd of a swale, at th e south east corner of the intersection of S 261 h Street a nd Benson Road S. Fro m here the flow en t ers a stormwater system located in the flowline of Benson Road S (there is s idewalk and c urb a nd gutter o n both s id es of Benson Road S from here to the north). The c atch bas in s in Benson Road S appear to be Type 2 structures, and also relatively deep. Th e exact direction of flow was diffi c ult t o determine, but it appears the flow conti nues in the piped system north on Benson Road S. This is a fully built out road with a p ipe and catch basin system in the flowline. The proposed project will discharge to the downstream system at a lower rate than currently existi ng. It will match the historical predeveloped flows, which are till forested cond itions. T he c urrent site is mainly lawn, two residences, and gravel driveways, th erefo re it is cu rrently discharging much more than historical predeve lo ped flows. Task 5: Mitigation of Existing or Potential Problems All runoff from the si te will be collected in a p iped storm system and directed to the proposed combined detention/water quality pond. From th ere, runoff w ill be discharged at the Flow Control Duration Standard (Forested Conditions) into the existing storm drainag e syst em in Benson Road S. 3-8 Figure 3.2 Offsite Analysis Downstream Flowpath 3-9 I ' "' l \ ,._ --i 9' I J • ,-I (I> ----'! ' s ,a·. •, -,_. -' - ,' .,---- ,._::_ _____ _ ·-..... .\ '. ... -;:/ r . ;,,r;.i,<~~ >=='-- 'r'1-"_l• ___ ,--. _: .. .,.i~--'-_-- ·:-· ----:>-:-:..-- -' '---, ··-- --; F \ ,_ _.,· '. ->-~=-.c.:· _-.:. __ --:-·- ~·~' . . •.. -: .... .!_ .. Y __ ,,~hl.1~,,~.. --.~· .. ·.··· ··.·····. ~ .. -· -•• _, ~} -§;~ --=. ( --<- -O> ~ -', ••• ~~.--~ -_.,-~:,,~~-:--,-;.... ~ ,: ... . , ~.:CF ,~5ac~~:;:~~ :.:.=~------- J.,.-._ -~---... --- 1a.. .. l _:1 __ -- •• ' --- ----,-,·,.·· ---- <_,-~-~--', ._ - '~ ~:~~0~~~~;-:~·· ----JIIL:'- I 11 -( ( -.,,~- -.. _ I·, i. I I. •, I \ I r I I I Photo 1. View to the east towards the alley and offsite properties. The east side of the site is app rox imately level with the neighboring property. Photo 2. View to the southeast towards the alley and corner of the project. The east side of the site is approximately level with the neighboring property and flows to the west. Photo 3. View offsite to the east of the intersection of the proposed alley and SE 165th St SE 1651h St. will be extended and brought through the project to Benson Road S. Photo 4. View to the west side of the property, from the east The project site slopes generally from east to west Photo 5. View al o ng the frontage looking towards the north on Benson Road S. The stormwater runoff from Benson Road Sand from the property is conveyed by a well defined, grass lined ditch. Photo 6. The runoff continues north on Benson Road S along the property frontage and reaches a culvert running underneath an existing gravel driveway. Photo 7. View of the culvert under the southernmost project driveway and continuation of the roadside ditch. Photo 8. The roadside ditch meets with a 12"0 CPP culvert. Photo 9. Continuation of the roadside ditch north along the frontage before entering a 12"0 RCP culvert under the northern existing gravel driveway. Photo 10. The 12"0 RCP culvert running under the project's north existing gravel driveway. Photo 11. Continuation offsite to the north of the roadside ditch in Benson Road S. Photo 12. Further c ontinuation to the north of the roadside ditch in Benson Road S. Photo 13. Further continuation to the north of the roadside ditch in Benson Road S. Photo 14. The roadside ditch enters into a 12"0 CPP culvert with a debris cage installed. Photo 15. The 12"0 CPP culvert enters this catch basin. It is a type 2 catch basin with a debris cage installed on top. Photo 16. View inside the type 2 catch basin, facing north. Row from the roadside ditch/culvert enters from the south. There is another inlet pipe from the eas~ S 27yth St Photo 17. Flow from the type 2 catch basin enters a catch basin with a solid lid, located in the landscaped area behind the sidewalk Photo 18. Flow continues to another catch basin with a solid lid. From here, the flow enters a type 2 catch basin with a debris cage installed on top. Photo 19. View looking east into the type 2 structure with the debris cage. Flow from the solid lid structure enters from the south (left side of the picture). There is an additional inlet on the north side of the structure (right side of the picture) that captures part of the Benson Road S runoff. This structure discharges to the west (top of the picture) across the street. Photo 20. Row crosses the street into a CB located in the flow line of Benson Road S. This CB is a type 2 CB and is deep. It was difficult to see all the way down to see in which direction flow headed. Water cou ld be heard running in the structure, and it appeared to be heading to the north along Benson Road S. Photo 21. Flow c ontinues north on Benson Road S to the north into this CB. Water could be heard running through the structure, similar to the upstream type 2 CB. Photo 22. Flow continues north on Benson Road S to the north into this CB. Water could be heard running through the structure, similar to the upstream CB. Photo 23. Flow continues north on Benson Road S to the north into this CB. Water could be heard running through the structure, similar to the upstream CB. The endpoint of the arrow is the point that is about ~ mile downstream from the project site. 4. FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS AND DESIGN 4. 1 Existing Site Hydrology The existing site consists of two single-family dwellings with associated gravel driveways, along with a few small detached structures. All structures on site will be demolished. The existing site is relatively flat (mean slope of about 7%, less than 10% max slopes on site) and slopes down generally from the southeast corner of the property towards the northwest. The pervious portions of the parcels are generally lawn except the northwest corner of the site is forested. According to the geotechnical report prepared by Earth Solutions NW, the soils on site are glacial till. See Figure 1.4 for the Soils Map. This report shows that the site is generally underlain with Till soils, which are incapable of infiltration. Therefore Till soils are used in the KCRTS model, with the entire predeveloped area being modeled as Till Forest. Approximately 2.32 acres of upstream area drains onto the site from the south (along Benson Road S) and the east (the area on the east side of the alley). To the east is a roadway cul-de-sac with nine lots and to the south is one lot. From inspection of available aerial data, these lots were modeled as 40% impervious. The right-of-way is modeled as 75% impervious. The predeveloped basin for the LaRosa project includes frontage along Benson Road S and the alley on the east side of the project TABLE 4.1 Pr D I peel Trlb e-eveo utary Ar ea SUBBASIN TOTALAREA TILL FOREST (Ac) (Ac) LaRosa + FrontaQe + Alley 4.78 4.78 TOTAL 4.78 4.78 See Figure 4.1 for a visual representation of the predeveloped tributary area 4.2 Developed Site Hydrology The project will create 21 single family lots with associated roadway, sidewalk, driveways, roof areas, landscaped yards, and a detention pond and StormFilter Manhole. There will be one drainage area within the project According to the zoning code, the maximum impervious area allowed by the City of Renton Zoning Code 4-2-11 QA for R-8 zoned lots is 75%. However, per City of Renton 1.2.3.3, the site will utilize Flow Control BMP C2.9 Reduced Impervious Surface Credit, and reduce on- site allowable impervious area by 10%. Therefore, building rooftops and impervious areas (driveway, porch, patios) are modeled as 65% impervious. Right of Way areas a modeled as 70% impervious. The detention pond and Storm Filter Manhole are located in the northwest comer of the site. The detained/treated runoff will discharge to the existing roadside ditch along the east side of Benson Road S, which is the site's natural discharge location. The frontage improvement area, along with a portion of the proposed roadway, and a portion of the alley on the northeast side of the site will be unable to be captured by the pond and will be treated as bypass area, based on elevation. However, a portion of the 4-1 upstream frontage along Benson and the alley southeast of the property will drain onto the project. These areas will be treated and detained, which will offset the area on the frontage that is not able to be collected by the proposed system. These bypass areas total 0.26 acres in size. Essentially, the portion of the upstream frontage and upstream alley being detained will be added to the developed basin, while the portion not treated will be removed. In addition to the above, a portion of S 281h Street will be routed through the combined detention/water quality pond. This flow will be treated but will flow through the storm drainage pond and will not be detained, it will be sized as the same flow in the pre and post developed scenarios .. TABLE4.2 D dP dD eve ope on etalned Area SUBBASIN TOTAL IMPERV. TILL AREA AREA(Ac) GRASS (Ac) {Ac) LaRosa 4.78 2.94 1.84 Offsite Area 2.32 1.04 1.28 TOTAL 7.10 3.98 3.12 The total bypassed area is 0.26 acres of ROW area. According to KCRTS (sized as 70% impervious), the 100 year flow rate is 0.097 els, which is less than 0.1 els; therefore compensatory mitigation is not required. However, upstream area equal to the bypass area (0.26 acres) will be treated and detained, so it will not be modeled as bypass area The upstream area 100 year flowrate is 0.718 els. The onsite, developed, 100 year flow rate is 1.69 els. Therefore, the 100 year offsite ftowrate is less than 50% of the 100 year developed flowrate, and is acceptable per the 2009 Manual Section 1.2.3.2.F. See Figure 4.2 for a visual representation of the Developed Tributary Area 4.3 Perfonnance Standards Performance Standards for flow control design use the KCRTS Methodology with hourly time steps as described in Section 4.4 below. Runoff files for the existing, proposed, and bypass conditions were created using the historic KCRTS time series data sets for the SeaTac Rainfall Region with a Correction Factor of 1.0. The site requires basic water quality treatment. Water quality will be satisfied with a StormFilter Manhole, which will follow the detention pond. 4-2 4.4 Flow Control System The pond was sized per the requirements in the 2009 Surface Water Design Manual. Per the City of Renton's Flow Control Application Map, the project site is in the Flow Control Duration Standard (Forested Conditions) area This standard requires the site to match the durations of high flows at their predevelopment levels for all flows from one-half of the 2 year peak flow up to the 50 year peak flow. The offsite flows being routed through the pond are not subject to flow control, therefore the offsite flows will be added to the predeveloped and developed flows. Predevcombined = predev (onsite) + offsite flows Devcombined = dev (onsite) + offsite flows The target flows are calculated as follows: 50% 2 year: 50% of the 2 year from predev (onsite) + offsite 2 year 50 year: predev 50 year + offsite 50 year The pond's inflow will be modeled using the devcombined time series and the pond's outflow will be the rdout time series. This rdout time series will match the Flow Control Duration Standard (Forested Conditions). KCRTS v6.0 was used to design the proposed pond. Procedures and design criteria specified in the 2009 Surface Water Design Manual were followed for the hydrologic and hydraulic modeling. The KCRTS pond sizing output is included in Appendix A There will be no net downstream effect after development An equivalent upstream area will be detained and treated to negate the bypass area. Upstream offsite areas, which were previously undetained and untreated, will be treated and released in the site's natural discharge point The KCRTS output models the required detention volume as 36,936 cubic feet of storage, with 6.0 feet of detention. The proposed pond provides 38,906 cubic feet of storage, which results in a construction factor of 5.3%. 4-3 Figure 4.1 Pond Predeveloped/Developed Tributary Areas 4-4 . --~ -z ' 0 ~ ~ § > } .1l ~ r .; g <{ ~ >-f-z ::J 0 0 (.'.} z i w I.!) w (.'.} a: z CY) (\J a.: ~ f- (j) (\J z 0 i== 0 w (/) u.. 0 s:t" ' ..... ~ z w I f- u. 0 z 0 i== a: 0 a. <{ + e ~ 0 ., ;... 0 I st ...J <( ~ > I! w r- w ~ I! ...J 0 :) <( 0 0 r- (/) z 0 (.) .,,np,1,j·")l"I .-<,ll)..>!>P~Ol I JUilwil~ovol"'I 1:>ilre,d I l'>p O.y, :> end ~u u .Oc ~-CIJ 6 .. !~ilAJf'S, ;.)V01 fiv;,;)~u:~u] v•:J UJO::>"l!/\!::>WSW.M.MM ~:=~~ !~&;~ Jl<llilo\.l -?•1Ye)OlJ l ~l @ I GI coooa vM ·.<l!M 10,opo.aJ 1;1=*=1 SOZ Ollr'IS ·s OJt,,V 418 OOt,CC 0 1 1 s1c1 33N l ~N3 ~N I .L H i s NO o e \ / NO~NIHS'IIM 'v'.3Hv' 91~ .A.~vin s1~1 03d013/\303~d GNOd N01N3~ .:10 ,WO ~ B a ..- VSOl::IVl I J; ~ C') (9 ~ ~ u::: 0 S3V\JOH 0 t:13NNOO .. ..: ~ ~~ ~ Q "" I I I I I I I r-1 u < "' '"! "' <( .: .:. <( 0: z <( ~ z (I) iii w < C) >-- 0 ~ w 0.. 0 g ::, 5= 6 0 8 !': Vl z " 0.. 0. ::, §1~~ "6"512Un)I >!JOI'.) :i 9 PilllO!d If!/ IZ I, tlOl /tL/,.. :,:,iln;i.:, b•P'90-N]\1'l!'Q 1.1•il\i 10\P00\0£;1\seo~-'6.:\•oo.il\S~]\ \ : .. ,j \ r-.i.'r i ) .::.:).ss 8 . \:;Ji'. \ LEGEND ~ O(VELOPED BASlfJ AREA ~ UPSTREAM Of FSITE BAS~ AREA ITJI] BYPASS BASIN AREA ~ UPSTREAM BYPASS BASl h AR[A TRACT A S T O R M D RAINAGE FACILILTY OE IENIION REQUIRED . DETENTION PRO-.,,DED. 36.935 er 36.906 er 4.78 AC /.57 AC 0 .26 AC 0.26 A: N O T~E~=~~~~~~~- OffSITE AREA: ONSITE AREA: "REATED. BlJ I NO" DETAINED IPEAT[D Al'<D DET AINED T RACT A .r (STORM DRAI NAGE) // / \, y A PORTI ON O F T H E NW 1 /4 OF SECT ION 29, TWP . 23 N., RGE. 5 E, KING COUNTY, WA ~5'( PJ:.\SS LPSTREAM BYPASS BAS~ I I '-.... SCAL E : 1 " -4 0' ~--111111111111\ -LO 20 0 ,o CON TOUR I N TERVAL -1' !JPSTF<E;:.\i\;I 8'( P.t\SS 80 n B;:.\slf,J ~l RFv 1S 1CNS e,#() OCSCD1PT,OO.,,/O,O.T( 0 Y - ~t fi ~ *~ ~ -.. ;;~ . UJ * ~.'.'.'-~, .'=.'<I ' . C!-C 0 ~* ~ ~ ~ z _ ~ ~! ;; -z •o u_1;,., oC r (!l •o z ~:l; ?g' ;:~~ E t~ ,~ ....I >,.:. J, ..... < ~ 0 ;~! (.) ;] z g~ ·:; c;f ·u -U<'>u. E "' I II) 3 ' ~ •• •' ~ ' 0 r ~ l,J.1.!. ·> ~ uo_ z ~ z 'i: :2 3: ~ a:: <( (/) >-w a:: ~ ~ ~ ::::, 0 Cl) CD ii:: I 0 I- a: a: Cl w w Cl. z ~ 0 ...J z ..J w 0 G'.i 0 0 0 z 0 Cl. z 0 !z w "' u_ 0 ~ u JOO NO.: 1'5'0-00A-0 1:! owe NAU[· ~-06 DES•CNED BY· enc DRAWN AY '" CH(CK [O DY: °'" 10/;>R/101.J ~or PRI NT· FIG 4.1 2 or 3 ShECTS LEGEND ~ DEVELOPED OASIN AREA 4 . ·5 AC ~ UPSTREAM OFFSITE BASIN Al-'fA 2.32 AC OJI] BYPASS BASIN AREA O 26 AC ~ UPSTREAM OYPASS BASIN AREA O ,r, AC TRACT A STORM DRAINAGE FACILILTY DETENTION REQ UIRED, Dt H Nl ION PROVIDED: 36.935 Cf 38.906 Cf NOTE: OFFSITE APEA· 0NS1Tf ARE A I P[AI FD. BUT fJ OT OCTA 'JED TREATED AND DETAINED A PORTION OF THE NW 1 /4 OF SECTION 29, T WP. 23 N., RGE. 5 E, KING COUNTY, WA n SCALE: 1 " -4 0 ' r-..""'*.,,J 40 2 0 0 40 80 CONTO UR I NTERVAL -2 ' r.tC V ISIONS ..0 0CSClll1PT10<-1i0AT( .. I-~ ~ I- I-t--~ ~ I- -~i ~~ . ' ~E ~ -;:~ 't "* ~~ .. a:-. 0 ~-i~ ~ z _ ~! s -C - Z" W ~M ' C .;1 8 ( "" z"'" ~· ~~~ tf ...J > ,.:. E ~j -,< «-0 VIV ~.:;: 0 tl u,.;_ z g[ ·;; J~ 2~~ ·u -E II) m '! ~ ;,: ' ·, ;,: .. .. ;,: .I: 0 r• w' .? g v~ z § z I V) < ~ _J (j) <( a:: w ~ w ~ ~ 0 Cf) ~ I 0 ~ er: 0:: a: <( w 0 z ~ w a. z _J 0 0 _J w 0 G'.i 0 z 0 'z uJ Q:'. u. 0 ~ <.) .J0D NO IE,10-~ owe NPMC: l'P -06 DCSICN EO ev ~ OHAWN BY. '" C+i(Cl<CO BV: ~ OAfl. 10/2a/70U DAT[ Of" PRINf: FIG 4.1 3 0' 3 s.~rns 4.5 Water Quality Facility The project site requires basic water quality treatment. This treatment will be provided by a StormFilter Manhole following detention. Additionally, there will be a Stormgate flow splitting structure before the StormFilter to route flows that are above the water quality flow rate around the StormFilter Manhole. See Appendix F for the StormFilter and Stormgate calculations and worksheets. 4-6 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN A conveyance analysis was performed for the mainline storm drainage systems and the rooftop conveyance systems. The StormSHED results provided in Appendix C demonstrate that the pipe networks function per the requirements of the 2009 Stormwater Manual for peak storm conveyance. The proposed conveyance system's parameters are as follows: Backwater was analyzed using StormSHED 3G proprietary software, using the rational methodology to analyze each sub-basin area. The project is not located near a location with an IDF curve table created, therefore the IDF values for Seattle are used. The outlet system was sized using a fixed flow of the 100 year, 15 min developed storm, to model the maximum ftow rate possible through the pond outlet structures. Developed Land Uses used: Lawn (c=-0.25) Pavement and roofs (c=0.90) Rainfall Data Used: 25 year: 3.40 in 1 00 year: 3.90 in The time of concentration is set at the 2009 Stormwater Manual minimum, 6.3 minutes, to add conservatism to the system design. The system was designed to convey the 25 year storm with no capacity or backwater issues. Additionally, the system was tested with the 100 year storm to determine that no flooding or backwater would occur, even with overcapacity in pipes. Naming Convention used in StormSHED: • Drainage basins are referred to as "Basins" • Catch basins are referred to as "Nodes" • Pipes are referred to as "Reaches" The StormSHED output is located in Appendix C and includes the following: • Conveyance Analysis Table • Contributing Drainage Areas Table • 25 year conveyance analysis • 100 year conveyance analysis 5-1 6. SPECIAL REPORTS AND STUDIES Following are the reports and studies referenced for the proposed development: • Geotechnical Engineering Report, by Earth Solutions NW, LLC, dated September 10, 2013. (Appendix B) • Geotechnical Engineering Report [Coal Mine Hazard Area], by Earth Solutions NW, LLC, dated September 24, 2013. (Appendix B) 6-1 • 7. OTHER PERMITS The National Pollutant Discharge Elimination System (NPDES) pennit has been submitted to the Washington DOE and is pending approval.. This project also requires the following pennits: Building Permits Clearing & Grading Pennits 7-1 8. CSWPPP ANALYSIS AND DESIGN The permanent LaRosa pond will be used as a temporary sediment pond during construction. For this calculation, the tributary area is assumed to be fully built out The total contributing area to the proposed sediment pond is the same as the combined developed area, 7.08 acres. STEPS: 1.l Obtain the discharge rate for the 2-year/24 hour (15-minute) developed storm. Total Area= 7.08 acres Impervious Area = 4.04 acre Pervious Area = 3.04 acres Forest Area = 0.00 acres 02-1sm1n = 2.14 cfs (calculated using KCRTS) 2.) Determine the Surface Area (SA) required at the top of the pond with 1' of freeboard. SA = 010-15 m;n (2080) = 2.14 * 2080 = 4,451 sf Minimum pond surface area is 4.451 sf. (6,250 provided) 3.) Sizing the Dewatering Mechanism: a.) Principal Spillway (Riser Pipe) The diameter shall be the minimum necessary to pass the pre-developed 10-year, 24-hour design storm. Use Figure 5.3.4.H (KCSWDM) to determine this diameter (h = one foot). O,o-1Sm1n = 0.663 cfs Per Figure 5.3.4.H, the minimum riser diameter is 10 inches to convey this flow rate. However, a 12" riser pipe will be used. b.) Emergency Overflow Spillway The emergency overflow spillway shall convey the 100 year, 15-minute developed design storm. Minimum spillway width Nvl is 6.00 feet. 1) Determine minimum spillway width: W = Q,oo-15mrn 2.4H (3.21)(H'1') 0100-15m;n. 7.92 cfs H • 0.50 ft 8-1 (Equation 5-3 from KCSWDM) (Calculated using KCRTS) 4.l W = 7.92 fi ---~,.,~ 2.4(0.5) = 5.78 (3.21)(0.5 ,. ) Use 6.0 feet for spillway width c.) Dewatering Orifice 1.l Size the dewatering orifice (1" minimum diameter) per the following equation from the KCSWDM: A = A,(2h)os 0 (0.6)(3600)(T)(g 0 5 ) Where: Ao = orifice area (square feet) A. • pond surface area (square feet) H = head of water above the orifice (riser height in ft) T = dewatering Time (T = 24 hours) g = acceleration of gravity A = (4.451)(2(8.5))05 0 (0.6)(3600)(24)(32.2'") A 0 = 0.062sf 2.) Convert Orifice Area tAo) to Diameter (D) in inches D = 24~( 0.~ 62 ) = 3.37in Use 3-3/8" diameter for the dewatering orifice. Per the KCSWDM, the perforated pipe shall be a minimum of 2 inches larger than the orifice sizes. Use 6" diameter for the perforated pipe. Sediment Pond Summary: Basin Area= Developed Inflow 1 Oyr/24hr (15 min) • Pre-developed 1 Oyr/24hr • Surface area required = Emergency spillway width - 7.08 acre 7.92 els 0.663 els 4,451 sf 6.0 ft Refer to Appendix A for flow rate analysis 8-2 9. BOND QUANTITIES AND DECLARATION OF COVENANT The Bond Quantities, Declaration of Covenant, and Facility Summary sheets are provided in Appendix E. 9-1 10. OPERATIONS AND MAINTENANCE MANUAL The Operations and Maintenance Manual is provided in Appendix D. I 0-1 APPENDIX A KCRTS Pond Sizing Output LaRosa Pond KCRTS Output Pre-Developed Land Use Condition 4.78 0.00 o.ocoooo c.co 0.00 0.000000 C.00 0.00 0.000000 C.00 0.00 0.000000 0.00 0.00 0.00 0.00 predev.t.sf ST 1. 008000 0.00 0.00 0.00 0.00 0.000000 0.000000 0.000000 0.000000 Flow Frequency Analysis Ti~e Series Fiie:predev.tsf Project Location:Sea-Tac Ti~l Forest TL.! Pasture TJ lJ Gra~s Outwas:', Fcrcst Outwash Pasture Outwash Grass Wetland Impervious LogPearson III Coefficients Mean= -0.938 StdDev= 0.233 Skew= -0.148 ---Annual Peak F:ow Rates--------Flow Frequency Analysis------- Flow ?ate (CFS) 0 .142 0.276 0.303 0.096 0.074 0.107 0. 189 0.160 C. 125 0. :_33 0.109 0.203 0 .110 0.066 0.088 0.109 0.077 0.084 0.187 0.111 0.108 0.092 0.074 0.226 0 .100 0.108 0. 163 0.100 0.012 0.087 0.052 0. J 4 0 0.077 0.140 0.136 0.091 0.044 0.234 0.188 0.071 0.045 Rank 16 5 2 32 42 28 9 '.3 21 20 24 8 23 44 36 25 40 38 Ii 22 26 34 41 7 30 27 12 29 50 37 46 18 39 17 19 35 48 6 10 43 47 '::'ime of Peak 2/16/49 22:00 3/03/50 16:00 2/09/51 1/30/52 1/18/53 1/06/54 2/07/55 12/20/55 12/09/56 1/16/58 1/24/59 11/20/59 2/24/61 1/03/62 JI /25/62 I/ 0 I/ 64 11/30/64 1/06/66 1/19/67 2/03/68 12/03/68 1/13/70 12/06/70 2/28/72 1/13/73 1/15/74 12/26/74 12/03/75 3/24/77 12/10/77 2/12/79 12/15/79 12/26/80 10/06/81 1/05/83 1/24/84 2/11/85 1/18/86 1 i/24 /86 1/14/88 4/05/89 18:00 9:00 19:00 5:00 21:00 17: 00 15:00 20:00 2:00 21: 00 15:00 2:00 15:00 19:00 12:00 3:00 14:00 23:00 19:00 23:00 8:00 3:00 5:00 2:00 23:00 17:00 20:00 17:00 8:00 8:00 4: 00 15:00 8:00 11: 00 6:00 21:00 4:00 12:00 16: 00 --Peaks Rank Return Prob (CFS) Period 0.322 I 89.50 0.303 2 32.13 0.288 3 19.58 0.282 4 14.08 0.276 5 10.99 0.234 6 9.01 0.226 0.203 0.189 0.188 0.187 0.163 0 .160 0.157 0.146 o.:42 0.140 0.140 0.136 0.133 0.125 0 .111 0 .110 0.109 0.109 0 .108 0.108 0.107 0.100 0.100 0.098 0. 096 0.094 0.092 0.091 0.088 0.087 0.084 0.077 0. 077 0.074 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 7. 64 6.63 5. 86 5.24 4.75 4. 34 3.99 3.70 3.44 3.22 3.03 2.85 2. 70 2.56 2. 44 2.32 2.22 2 .13 2.04 I. 96 I. 89 I. 82 I. 75 I. 70 I. 64 I. 59 I. 54 I. 4 9 I. 45 1. 41 1. 37 1.33 1.30 1.27 1. 24 0.989 0. 969 0.949 0.929 0.909 0.889 0.869 0.849 0.829 0.809 0. 789 0. 769 o. 749 0. 729 0. 709 0.690 0.670 0.650 0.630 0.610 0.590 0.570 0.550 0.530 0.510 0.490 0.470 0.450 0.430 0.410 0.390 0.370 0.350 0.330 0.310 0. 291 0. 271 0.251 0.231 0. 211 0.191 0.322 1 0.787 4 0.094 33 0.098 31 0.027 49 0.146 15 0.288 3 0.157 14 0.055 45 Comp'.1ted Peaks Computed Peaks Computed Peaks Computed Peaks Computed Peaks Computed Peaks Comput.ed Peaks Comput.ed Peaks 1/09/90 9:00 4/05/91 2:00 1/27/92 17:00 3/73/93 0: 00 3/03/94 3:00 2/19/95 20:00 2/09/96 I: 00 1/02/97 9:00 1/07/98 10:00 Developed Land Use Condition 0.074 0. 071 0.066 0. 055 0.052 0.045 0.044 0.027 0.012 0.380 C.333 0.288 0.228 0.215 0.182 0 .117 0.077 42 1.21 43 1.18 44 1.15 4 5 1. 12 46 1.10 4 ·1 1. 08 48 1.05 4 9 1. 03 50 1.01 100.00 50.00 25.00 10.00 8.00 5.00 2.00 1. 30 8.171 0.151 0. 131 0. 111 0. 8 9 J 0. 071 0.051 C.031 0. 011 0.990 0.980 0. 960 0.900 0.875 0.800 0.500 0.231 ·O. CO 0.00 1. 84 C.00 0.00 0. 00 0.00 2.94 0.00 0.00 0.00 0.00 0.00 0.00 o.oc o.oc 0.000000 Till Forest 0.000000 TilJ Pasture 0.000000 Till Grass 0.000000 Out.wash Forest. 0.000000 Out.wash Pasture 0.000000 Out.wash Grass 0.000000 Wetland 0.000000 Impervious dev. t.;:;f ST 1.000000 Flow Frequency Analysis Time Series Fi:e:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Rate (CFS) 0.888 1. 48 0.909 0.707 0.678 0.826 0.852 0.832 0.989 0.868 0.646 0.837 0.741 0. 73] 0.740 0.828 0. 742 o. 748 1.14 1. 23 0.682 0. 754 0. 720 1.12 Rank Time of Peak 21 2/16/49 21:00 2 3/03/50 16:00 20 2/09/51 2:00 40 10/15/51 13:00 45 3/24/53 15:00 27 12/19/53 19:00 23 11/25/54 2:00 25 11/18/55 15:00 15 12/09/56 14:00 22 12/25/57 16:00 47 11/18/58 13:00 24 11/20/59 5:00 36 2/14/61 21:00 38 11/22/61 2:00 37 12/15/62 2:00 26 12/31/63 23:00 35 12/21/64 4:00 34 1/05/66 16:00 7 11/13/66 19:00 5 8/24/68 16:00 43 12/03/68 16:00 33 1/13/70 22:00 39 12/06/70 8:00 8 2/27/72 7:00 LogPearson III Coefficients Mean= -0.063 StdDcv= 0.110 Ske· ..... = 0. 4 32 -----Flow --Peaks (CFS) 1. 57 1. 48 1. 44 1. 42 1. 23 1. 23 1. 14 1. 12 1. 09 1. 05 1. 02 1. 02 1. 02 1. 00 0.989 0. 969 0. 963 0.953 0.940 0.909 0.888 0.868 0.852 0.837 Frequency Analysis------- Rank Retu~n Prob Period 1 89.50 0.989 2 32.13 0.969 3 19.58 0.949 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 14.08 10.99 9.01 7.64 6.63 5.86 5.24 4.75 4.34 3.99 3.70 3. 4 4 3.22 3.03 2.85 2.70 2.56 2. 44 2.32 2.22 2.13 0.929 0.909 0.889 0.869 0.849 0.829 0.809 0.789 0.769 0.749 0. 729 0.709 0.690 0. 670 0.650 0.630 0.610 0.590 0.570 0.550 0.530 O.E64 0.802 1.05 0. 681 0.791 1.09 0.953 0. 969 1. 02 1. 42 1. 00 0.800 0.685 0.963 1. 23 0.543 0.703 l. 57 i.44 0.779 0.507 0.589 0.776 1. 02 0.940 1. 02 16 28 10 44 30 9 18 16 11 4 14 29 42 17 6 49 41 3 3' 50 48 32 12 19 13 Comput.ed Peaks Compui::.ed Peaks Computed Peaks Computed Peaks Computed Peaks Compuled Peaks Computed Peaks Computed Peaks 1/13/73 11/28/73 12/26/74 12/02/75 8/26/Fi 9/17/78 9/08/79 12/14/79 11/21/80 10/06/81 2:00 9:00 23:00 20:00 2:00 2:00 15:00 21: 00 11: 00 0:00 10/28/82 16:00 1/03/84 I :00 6/06/85 1/18/86 I 0/2E/86 11/11/87 8/21/89 ]/09/90 11/24/90 1/27 /92 11/01/92 11/30/93 11/30/94 2/08/96 22:00 16:00 0:00 0:00 17:00 6:00 8:00 15:00 16:00 22:00 4:CO 10:00 l/02/97 6: 00 lC/04/97 15:00 0.832 0.8~8 0.826 0.802 0.800 0.791 0.779 0. 776 0. 754 0. 748 0. 742 0. 741 0. 740 0. 731 0. 720 0.707 0.703 0.685 0.682 0.681 0.678 0.664 0. 64 6 0.589 0.543 C.507 1. 69 1.54 1. 39 1.21 1.17 1. 06 0.850 0. 711 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Bypass Land use Condition (for flow rate purposes) 0.00 0.00 0. 08 0.00 0.00 0.00 0.00 0.18 bypass.ts£ ST 1. 000000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.000000 Till Forest 0.000000 Till Pasture 0.000000 Till Grass 0.000000 Out.wash Forest 0.000000 Outwash Pasture 0.000000 Out.wash Grass 0.000000 Wetland 0.000000 Impervious 1. 9E 1. 89 1. 82 1. 7 5 1. 70 1. 64 1. 59 1. 54 1. 49 l. 45 ; . 4] l. 37 i. 33 l. 30 1. 27 1. 24 1. 21 1. 18 1.15 1.12 1.10 1. 08 1. 05 1. 03 1. 01 100.00 50.00 25.00 10.00 8.00 5.00 2.00 1.30 0 .. )10 0.490 0.470 0.450 0.430 0.410 0.390 0.370 0.350 0.330 0.310 0.291 0. 271 0.251 0.231 0.211 0.191 0.171 0.151 0.131 D .111 0.091 0.071 0.051 0.031 0. 011 0.990 0.980 0.960 0.900 0.875 0.800 0.500 0.231 Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Sea-Tac LogPearson III Coefficients Mean= -1.293 StdDev= 0.106 Skew= 0.463 ---Annual Flow Rate (CFS) 0.052 0.084 0.052 0.043 0.040 0.048 0.050 0.049 Peak Flow Rates--- Rank Time of Peak 21 2/16/49 21:00 2 3/03/50 16:00 20 2/09/51 2:00 40 10/15/51 13:00 44 3/24/53 15:00 27 12/19/53 19:00 23 11/25/54 2,00 24 11/18/55 15:00 -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.090 1 89.50 0.989 0.084 0.083 0.083 0.073 0. 073 0.067 0.066 2 3 4 5 6 7 8 32 .13 19.58 14.08 10.99 9.01 7.64 6.63 0. 969 0.949 0.929 0.909 0.889 0.869 0.849 0.0 8 1 12/09/56 14:CO U.064 9 S.86 C.829 0. (I 1 2 12/25/57 16:00 0.061 10 5.24 C.809 0.0 8 4 ll/:8/58 13:CO 0. 0 E c, 11 4.75 C. 789 0. QL,9 20 11/20/59 5:CO 0. 068 12 4. 34 C. 769 0.044 36 2/14 /61 21:00 0.060 13 3.99 0.749 0.043 38 11/22/61 2:00 0.058 H 3.70 0.729 0.044 37 12/15/62 2:00 0.058 15 3.44 0.709 0.049 26 12/31/63 23:00 0.058 16 3.22 0.690 0.044 34 12/21/64 4:00 0.056 17 3.03 0.670 0.044 35 1/05/66 16:00 0.056 J 8 2.85 0.650 0.067 7 11 /13/66 19:00 0.054 19 2.70 0.630 0.073 5 8/24/68 16:00 0.052 20 2.56 0.610 0 . .J40 43 12/03/68 16:00 0.052 21 2.44 0.590 C.044 33 1/13/70 22: 00 0.051 22 2.32 0.570 0.042 0 :2/05/70 9:00 0.050 23 2. 22 0.550 0. 0 6i:: 9 2/27/72 7:00 0.049 24 2. 13 0.530 0.039 46 1/13/73 2:00 0.049 25 2.04 0.510 0.047 29 11/28/73 9:00 0.049 26 l. 96 0. 4 90 0.061 1 0 12/26/74 23:00 0.048 27 1. 89 0.470 0.040 45 12/02/75 20:00 0.048 28 1. 82 0. 4 5 0 0.048 28 8/26/77 2:00 0.047 29 1. 75 0. 430 0.066 8 9/17/78 2:00 0.04"/ 30 1. 70 0.410 0.058 16 9/08/79 15:00 0.046 31 1. 64 0.390 0.056 17 12/14/79 21:00 0.046 32 1. 59 0.370 0.060 11 11/21/80 11:00 0.044 33 1. 54 0.350 0.083 3 10/06/81 0:00 0.044 34 1. 4 9 0.330 0.060 12 10/28/82 16:00 0.044 35 1. 4 5 0. 31 0 0.047 30 :/03/84 1:00 0.044 36 1.41 0.291 0.041 42 6/06/85 22:00 O.C44 37 l. 37 0. 271 0.056 18 1/18/86 16:00 0.043 38 l . 33 0.251 0. 073 6 10/26/86 0:00 C.043 39 1.30 0.231 o. o:n 49 11/11/87 0:00 0. 0 4 3 40 1.27 0.211 0. 04 3 39 8/21/89 17:00 0.042 41 1. 24 0. 191 0.090 1/09/90 6:00 0.041 42 1.21 0.171 0.083 4 11/24/90 8:00 0.040 43 1. 18 0.151 C.046 32 1/27/92 15:00 0.040 44 1. :s 0.131 O.C31 50 '.1/01/92 16:00 0.040 45 l. 12 0 .111 0.036 48 11/30/93 22: 00 0.039 46 1.10 0.091 0.046 31 11/30/94 4:00 0.038 47 1. 08 0.071 0.058 14 2/08/96 10:00 0.036 48 1. 05 0.051 0.054 19 1/02/97 6:00 0.033 49 1. 03 0.031 0.060 13 10/04/97 15:00 0.031 so 1. 01 0. 011 Computed Peaks 0.097 100.00 0.990 Computed Peaks 0.089 50.00 0.980 Computed Peaks 0.081 25.00 0. 960 Computed Peaks 0.070 10.00 0.900 Computed Peaks 0.068 8.00 0.875 Computed Peaks 0.062 5.00 0.800 Computed Peaks 0.050 2.00 0.500 Computed Peaks 0.042 l . 30 0.231 Offslte Land Use Condition 0.00 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 1. 28 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 1. 04 0.00 0.000000 Impervious offsite.tsf ST 1.000000 FlO' .... ' ::::equency Analysis LogPearsc:1 III Coefficients Time Series F le:offsite.tsf Mean= -0.463 StdDev= 0.122 Project Locut on:Seu-Tac Skew= 0.398 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 0.361 20 2/16/49 21: 00 0.681 89.50 0.989 0.659 2 3/03/50 16:00 0.659 2 32. 13 0. 969 0.383 19 2/09/51 2:00 0.612 3 19.58 0.949 0.266 42 10/15/51 13: 00 0.570 4 14.08 0.929 0.266 43 3/24/53 15:00 0.481 5 10.99 0.909 0.332 26 12/19/53 19:00 0.478 6 9.01 0.889 0.335 24 11/25/54 2:00 0.466 7 7. 64 0.869 0.334 25 12/20/55 17:00 0.455 8 6.63 0.849 0.405 13 12/09/56 14:00 0.442 9 5.86 0. 829 0.346 22 12/25/57 l 6: 00 0. 436 10 5.24 0. 809 0.253 46 11/18/58 13:00 0. 417 11 4.75 0.789 0.339 23 11/20/59 5:00 0.412 12 4.34 0.769 0.299 34 2/} 4 /6] 21:00 0. 405 13 3.99 0.749 0.284 39 11/22/61 2:00 0.404 14 3.70 0. 729 0.301 33 12/15/62 2:00 0.403 15 3.44 0.709 0.3?9 28 12/31/63 23:00 0.397 16 3.22 0.69C 0.292 38 12/21/64 4:00 0.389 17 3.03 0.67C 0.298 35 1/05/66 16: 00 0.386 l 8 2.85 0.650 0. 455 8 11/13/66 19:00 0.383 19 2. 70 0.630 0. 481 5 8/24/68 16:00 0.361 20 2.56 0.610 0.274 41 12/03/68 16:00 0.347 21 2. 4 4 0.59C 0.301 32 1/13/70 22:00 0.346 22 2.32 0.570 C.292 37 12/06/70 8:00 0.339 23 2.22 0.550 0.478 6 2/27 /72 7:00 0.335 24 2 .13 0.530 0.262 44 1/13/73 2:00 0.334 25 2.04 0.510 0.329 27 11/28/73 9:00 0. 33;;:: 26 1. 96 0.490 0.442 9 ;2/26/74 23:00 0.329 27 1. 89 0. 4 70 0.275 40 12/02/75 20:00 0.329 28 1. 82 0.450 0. 296 36 8/26/77 2:00 0. 322 29 l. 7 5 0.430 0.417 11 9/22/78 19:00 0. 311 30 I. 70 0.410 0.347 21 9/08/79 15:00 0.302 31 1. 64 0.390 0.397 16 12/14/79 21:00 0.301 32 1. 59 0.370 0.403 15 11/21/80 11: 00 0.301 33 1. 54 0.350 0.570 4 10/06/81 0:00 0.299 34 1. 49 0.330 0.386 18 10/28/82 16:00 0.298 35 1. 45 0.310 0. 322 29 1/03/84 1:00 0. 296 36 1. 41 0.291 0.260 45 6/06/85 22:00 0.292 37 1. 37 0. 271 0. 4 0 4 14 1/18/86 lE: 00 0.292 38 1. 33 0.251 0. 4 66 7 10/26/86 0:00 0.284 39 1. 30 0.231 0.202 49 1/14/88 0:00 0. 275 40 1. 27 0. 211 0.249 47 8/21/89 17:00 0. 274 41 1.24 0.191 0.681 1 1/09/90 6:00 0.266 42 1.21 0.171 0.612 3 11/24/90 8:00 0.266 43 1.18 0.151 0.311 30 1/27/92 15:00 0.262 44 1.15 0 .131 0.188 50 12/10/92 6:00 0.260 45 1. 12 0 .111 0.218 48 11/30/93 22:00 0.253 46 1.10 0.091 0.302 31 11/30/94 4: 00 0.249 47 1. 08 0.071 0.436 10 2/08/96 10: 00 0.218 48 1. 05 0.051 0.389 17 1/02/97 6:00 0.202 49 1. 03 0.031 0.412 12 10/04/97 15:00 0.188 50 1. 01 0. 011 Computed Peaks 0. 718 100.00 0.990 Computed Peaks 0.650 50.00 0.980 Computed Peaks 0.584 25.00 0. 960 Computed Peaks 0. 4 99 10.00 0.900 Computed Peaks 0.482 8.00 0.875 Com::iu:.cd Peaks Corr,puted Peak.s Computed Peaks 0. 4 33 0.338 0.277 ;J. 00 2.00 1. 30 C.800 0.500 0.231 As stated in Section 4, the predeveloped and developed flows have been combined with the offsite flow (which is flow-through, no detention requirements). Predevcombined Flow Frequency Analysis predev.tsf + offsite.tsf = predevcombined.tsf Flow Frequency Analysis LogPearson III Coefficients Time Series File:predevcombined.tsf Mean= -0.370 StdDev= 0.145 Project Location:Sea-Tac Skew= 0.510 ---Ann,..1al Flow Rate !CFS) 0.491 0.936 0. 596 0.349 0.309 0.410 0. 489 0.495 0.524 C.396 C.317 0.507 0.377 0.285 0.378 0.415 0.341 0.378 0.550 0.482 0.370 0.378 0. 367 0.674 0.341 0.378 0.604 0.374 0.297 0. 419 0.348 0.478 0.412 0.708 0.387 0. 396 0.262 0. E18 0.550 0.261 0.249 0. 965 0.854 0.372 Peak F~ow Rates--- Rank ~ime of Peak 16 2/16/49 21,00 2 3/03/50 lE:00 9 2/09/51 14:00 38 1/30/52 s,oo 43 3/24/53 15,00 24 12/19/53 19:00 17 2/07/55 17:00 15 12/20/55 17:00 13 12/09/56 14:00 26 12/25/57 16:0C 42 1/26/59 20,00 14 11/20/59 21:00 32 2/14/61 21,00 45 11/22/61 2:00 28 l2/15/62 2:00 21 12/31/63 23,00 40 12/21/64 4,00 29 1/05/66 16,00 10 ]/19/67 14,00 18 5/24/68 16:00 35 12/03/68 16,00 30 1/13/70 23,00 36 12/06/70 8:00 6 2/27/72 7,00 41 1/13/73 2:00 31 11/28/73 9,00 8 12/26/74 23:00 33 12/02/75 20,00 44 8/26/77 2,00 20 9/22/78 19:00 39 9/08/79 15:00 19 12/14/79 21:00 23 11/21/80 11:00 4 10/06/81 15,00 27 10/28/82 16:00 25 1/03/84 1,00 47 6/06/85 22,00 7 1/18/86 16,00 11 11/24/86 3:00 48 1/14/88 12,00 49 8/21/89 17,00 1 1/09/90 6:00 3 11/24/90 8:00 34 1/27/92 16,00 -----Flow Frequency Analysis------- --Peaks Rank Return Prob (CFS) Period 0.965 89.50 0.989 0.936 0.854 0.708 0.704 0.674 0.618 0.604 0.596 0.550 0.550 0.536 0.524 0.507 0.495 0. 4 91 0.489 0.482 0.478 0.419 0.415 0.412 0.412 0.410 0. 396 0. 396 0.387 0.378 0.378 0.378 0.378 0. 377 0.374 0. 372 0.370 0.367 0. 361 0.349 0.348 0.341 0.341 0.317 0.309 0. 297 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 32.13 19.58 14.08 10.99 9.01 7. 64 6.63 5.86 5.24 4. 'i :J 4.34 3.99 3. 70 0. 969 0.949 0.929 0.909 0.889 0.869 0.849 0.829 0.809 0.789 0.769 0.749 0. 729 3.44 0.709 3.22 0.690 3.03 0.670 2.85 0.650 2.70 0.630 2.56 0.610 2.44 0.59C 2.32 0.57C 2.22 0.55C 2.13 0.530 2.04 0.510 1.96 0.490 1.89 0.470 1.82 0.450 1.75 0.430 1.70 0.410 1.64 0.390 1.59 0.370 1.54 0.350 1.49 0.330 1.45 0.310 1.41 0.291 1.37 0.271 1.33 0.251 1.30 0.231 1.27 0.211 1.24 0.191 1.21 0.171 1.18 0.151 1.15 0.131 0. :>)9 " ,,o 3/22/93 22:00 0.285 ~5 1 ' ,, 0.111 0.219 50 ll/30/9J n:oo 0. 21S9 46 :i_. 10 0.091 0.361 37 2/18/95 20: 00 0.262 4'/ 1. OB 0.071 0.784 5 2/08/96 10:00 0. 7 61 48 1. 05 0.051 0. S3E 12 1/02/97 6:00 0.249 4 9 l. 03 0.031 0.412 22 10/04/97 15:00 0.219 50 1. 01 0. 011 Cor.iputed Per.1ks 1. cs 100.00 0.990 Computed Peaks 0.926 50.00 0.980 Computed Peaks 0.809 25.00 0. 960 Computed Pea Ks O.E64 10.00 0.900 Computed Peai<:s 0.636 8.00 0.875 Computed Peaks 0.559 5.00 0.800 Computed Peaks 0.414 2.00 0.500 Computed Peaks 0.329 1..30 0.231 Devcombined Flow Frequency Analysis dev.tsf + offsite.tst = devcombined.tsf Flow Frequency Analysis Log Pearson III Coef:'.:icie:-its Time Series File:devcombined.tsf Mean= 0.083 StdDev= 0. 113 Project Loca tic·n: Sea-~ac Skew= C.405 ---Annual Peak Flow Rates--------Flow Frequency P..nalysi s------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob !CFS) (CFS) Period 1. 25 21 2/16/49 21:00 2.25 1 89.50 0.989 2 .14 2 3/03/50 16:00 2.14 2 32.13 0. 969 1. )9 20 2/09/51 2:00 2.05 3 19.58 0.949 C.972 40 10/15/51 13:00 1. 99 4 14.08 0.929 0.944 45 3/24/53 15:00 1. 72 5 10. 99 0.909 1. 16 25 12/19/53 19:00 1 . 69 6 9.01 0.889 1.19 23 11/25/54 2:00 1. 60 7 7. 64 0.869 1.16 26 11/18/55 15:00 1. 59 8 6.63 0.849 1. 39 14 12/09/56 14:00 1. 50 9 5.86 0.829 1. 22 22 12/25/57 16:00 1. 4 9 10 5.24 0.809 0.899 47 11/18/58 13:00 1. 45 11 4. 7 5 0.789 1.18 24 11/20/59 5:00 1. 43 12 4.34 0.769 1. 04 35 2/14/61 21:00 1. 42 13 3.99 0.749 1. 01 38 11/22/61 2:00 1. 39 14 3. 70 0.729 J • 0 4 36 12/15/62 2:00 1. 39 15 3. 44 0.709 1.16 27 12/31/63 23:00 1. 37 lE 3.22 0.690 1. 03 37 12/21/64 4:00 1. 37 17 3.03 0. 670 1. 04 34 1/05/66 16:00 1. 33 18 2.85 0.650 1. 59 8 11/13/66 19:00 1. 30 19 2.70 0.630 1. 72 5 8/24/68 16:00 1. 29 20 2.56 0.610 0.956 41 12/03/68 16:00 1. 25 21 2, 4 4 0.590 1. 06 33 1/13/70 22:00 1. 22 22 2.32 0.570 1. 01 39 12/06/70 8:00 1.19 23 2.22 0.550 1. 60 7 2/27/72 7:00 1. 18 24 2.13 0.530 0. 925 46 1/13/73 2:00 1.16 25 2.04 0.510 1.13 28 11/28 /7 3 9:00 1.16 26 1. 96 0.490 1. 50 9 12/26/74 23:00 1. 16 27 1.89 0.470 0.956 42 12/02/75 20:00 1.13 28 1.82 0.450 1. 09 31 8/26/77 2:00 1.12 29 1. 7 5 0.430 1. 49 10 9/17/78 2:00 1. 09 30 1. 70 0.410 1. 30 19 9/08/79 15:00 1. 09 31 1.64 0.390 1. 37 16 12/14/79 21: 00 1. 08 32 1.59 0.370 1. 42 13 11/21/80 11: 00 1. 06 33 1.54 0.350 1. 99 4 10/06/81 0:00 1. 04 34 1. 4 9 0.330 1. 39 15 10/28/82 16:00 1. 04 35 1.45 0.310 1.12 29 1/03/84 1:00 1. 04 36 1.41 0.291 0.945 44 6/06/85 22: 00 1. 03 37 1.37 0. 271 1 . 37 17 1/18/86 16: 00 1.01 38 l. 33 0.251 1. 69 6 :0/26/86 U:00 1.01 39 1-. 30 0.23] 0. 73.5 49 11/11/87 0:00 0. 972 40 1. 27 0. 211 0.952 43 8/21/89 17:00 0.956 41 l. 24 0. 1 91 2.25 1 1/09/90 6: 00 0.9~,6 42 1. 21 0.1n 2.05 3 11/24/90 8:00 0.952 43 1.18 0. 151 1. 09 30 1/27/92 15:00 0.945 44 1.15 0. 131 0.690 50 11/01/92 16: 00 0.944 45 1.12 0 .111 0.807 48 11/30/93 22:00 0.925 46 1.10 0.091 1. 08 32 11/30/94 4:00 0.899 47 1. 08 0.071 1. 45 11 2/08/96 10:00 0.807 48 1. 05 0.051 1.33 18 1/02/97 6:00 0.735 49 1. 03 0.03: ::. . 43 12 10/04/97 15:00 0.690 SC 1. 01 0.011 Computed Peaks 2.39 100.00 0.990 Computed Peaks 2. 16 50.00 0.980 Computed Peaks 1. 98 25.00 0. 960 Computed Peaks 1. 71 :i.o. oo 0.900 Computed Peaks 1. 65 8.00 0.875 Computed ?eaks 1.50 5.00 0.800 Computed Peaks 1.19 2.00 0.500 Computed Peaks 0.988 1. 30 0.231 Devcombined 15 min Flow Rates Flow t:::equency Analysis LogPearson I :i: I Coefficients T:me Series F1le:dev15comblned.tsf Mean= 0.361 Std Dev== 0. 164 Project Location:Sea-Tac Skew= 1.384 ---Annual Peak Plow Rates--------Flew Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob (CFS) (CFS) Period 3 .19 9 2/16/49 17: 45 9 . l 1 1 89.50 0.989 4.30 5 3/03/50 15:00 5.48 2 32.13 0. 969 1. 8 6 35 8/27/51 18:00 4.88 3 19.58 0.949 2.18 28 10/17 /51 7: 15 4 . 4 4 4 14.08 0. 929 1. 58 43 9/30/53 3:00 4.30 5 10.99 0.909 1. 81 38 :2/19/53 17:30 3.66 6 9.01 0. 889 1.53 46 7 /30/55 21: 15 3.29 7 7.64 0.869 2.29 20 10/04/55 10:00 3.22 B 6.63 0. 84 9 2.20 25 12/09/56 12:45 3 .19 9 5.86 0.829 2.03 32 1/16/58 10:00 2.71 10 5.24 0.809 2.59 14 10/18/58 19:45 2. 67 11 4.75 0.789 2.61 13 10/10/59 22:00 2. 62 12 4.34 0. 769 2.20 26 2/14/61 20:15 2.61 13 3.99 0. 749 1. 83 37 8/04/62 13:15 2.59 14 3.70 0. 729 1. 79 39 12/01/62 20:15 2.47 15 3.44 0.709 l. 40 48 6/05/64 15:00 2. 41 16 3.22 0.690 2.07 30 4/20/65 19:30 2.40 17 3.03 0.670 1. 39 49 1/05/66 15:00 2.38 18 2.85 0.650 2.40 17 11/13/66 17:45 2.35 19 2.70 0.630 4.88 3 8/24/68 15:00 2.29 20 2.56 0.610 2. 14 29 10/20/68 12:00 2.29 21 2.44 0.590 1. 28 50 1/13/70 20:45 2.23 22 2.32 0.570 1. 55 45 12/06/70 7:00 2.23 23 2.22 0.550 3.29 7 12/08/71 17:15 2.20 24 2. 13 0.530 1. 84 36 4/18/73 9:30 2.20 25 2.04 0.510 2.23 22 11/28/73 8:00 2.20 26 1. 96 0.490 2.38 18 8/17/75 23:00 2.19 27 1. 89 0.470 1. 64 42 10/29/75 7:00 2.18 28 1. 82 0.450 1. 50 47 8/23/77 14:30 2 .14 29 1. 7 5 0.430 2.67 11 9/17/78 1:00 2.07 30 1. 70 0.410 3.66 6 9/08/79 13:45 2.06 31 1. 64 0.390 2.62 12 12/14/79 20:00 2.03 32 j_. :;.g 0.370 2, 4 7 15 9/21/81 8:00 2.03 33 1. 54 0.350 .5. 4 8 / ·, 0/05/81 22:15 1. 94 34 1. 49 0.330 ,, ., -~ L, L-.., 23 10/28/82 16: 00 1. 8 6 35 1. 45 0.310 1. 70 40 1/02/84 23:30 1. 84 36 1. 41 0.291 1. 58 44 6/06/85 21:15 1. 83 37 : . 37 0.271 2.35 19 10/27/85 10:45 1. 81 38 1.33 0.251 2.71 10 10/25/86 22:45 1 . 7 9 39 1. 30 0.231 2. 19 27 5/13/88 17:30 1. 70 40 1. 27 0, 211 2.03 33 8/21/89 16:00 1. 69 41 1. 24 0, 191 3.22 8 1/09/90 5:30 1. 64 42 1. 21 0, 171 2. 20 24 4/03/91 20:15 1. 58 43 1.18 0.151 : . 69 4 1 1/27/92 15:00 1.58 44 1.15 0. 131 2.06 31 6/09/93 12:15 1.55 45 1.12 0. Ill 1. 94 34 11/,7/93 16:45 :.53 46 1.10 J. 091 2.29 21 6/05/95 ,7:00 1. 50 47 1. 08 0.071 2.41 16 7 /19/96 19:30 1. 40 48 1. 05 0.051 9.11 1 12/29/96 11: 4 5 1. 39 49 1. 03 C.031 4. 4 4 4 10/04/97 1 4 : 1 5 1. 28 50 1. 01 0.011 Computed Peaks 7.90 100.00 0.990 Computed Peaks 6.38 50.00 0.980 Computed Peaks 5. 14 25.00 0.960 Computed Peaks 3.81 10.00 0.900 Corr.puted Peaks 3.59 8.00 0.875 Computed Peaks 3.00 5.00 0.800 Computed Peaks 2 .11 2.00 0.500 Computed Peaks 1. 72 1. 30 0. 231 Rows used for Target Duration Curve Calculatlon 50% of 2 year predev.tsf + 2 year offsite.tsf 0.059 + 0.338 = 0.397 els <--first interval 50 year flow: 50 year predev.tsf + 50 year offsite.tsf 0.333 + 0.650 = 0.983 els Interval Size: (50 year -first interval)/35 (0.983 -0.397)/35 0.0167 LaRosa Pond Facility Retention/Detention Facility Type of Facility: Side Slope: Pond Bottom Length: Pond Bottom Width: Pond Bottom Area: Top Area at 1 ft. FB: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Detention Ponci. 3.00 H:lV 108.00 ft 30.00 ft 3240. sq. ft 10800. sq. ft 0.248 acres 6.00 ft 0.00 ft 36936. cu. ft 0.848 ac-ft 6.00 ft 18.00 inches 2 Full Head Pipe Orifice# Height (ft) 0.00 5.20 Diameter (in) 2.50 l. 7 5 Discharge (CFS) 0.415 0.074 Diameter (in) 1 2 Top Notch Weir: Rectangular Length: 7.00 in Wej r Height: 5. 75 ft Outflow Rating Curve: None Stage Elevation Storage (ft) (ft) (cu. ft) (ac-ft) 0.00 0.00 0. 0.000 0.03 0.03 98. 0.002 0.05 0.05 16 3. 0.004 0.08 0.08 262. 0.006 0 .10 0 .10 328. 0.008 0. 13 0 .13 428. 0.010 0.16 0. 16 529. 0.012 0.18 0 .18 597. 0. 014 0. 21 0. 21 699. 0. 016 0.33 0.33 1115. 0.026 0. 44 0.44 1507. 0.035 0.56 0.56 1946. 0.045 0.68 0.68 2398. 0.055 0. 80 0.80 2863. 0.066 0.91 0.91 3300. 0.076 I. 03 1. 03 3790. 0.087 1. 15 1.15 4292. 0.099 1. 27 I. 27 4807. 0.110 I. 38 I. 38 5291. 0.121 I. 50 I. 50 5832. 0 .134 1. 62 1. 62 6386. 0.147 I. 7 4 I. 7 4 6954. 0.160 I. 86 I. 8 6 7 536. 0.173 I. 97 I. 97 8081. 0 .186 2.09 2.09 8690. 0.199 2.21 2.21 9312. 0.214 2.33 2.33 994 9. 0.228 2.44 2.44 10545. 0.242 2.56 2.56 11209. 0.257 2.68 2.68 11888. 0. 273 2.80 2.80 1258 i. 0.289 4. 0 Discharge Percolation (cfs) (cfs) 0.000 0.00 0. 027 0.00 0.039 0.00 0.047 0.00 0.055 0.00 0. 061 0.00 0.067 0.00 0. 072 0.00 0.077 0.00 0.097 0.00 0 .113 0.00 0.127 0.00 0.140 0.00 0. 151 0.00 0.162 0.00 0.172 0.00 0.182 0.00 0.191 0.00 0.199 0.00 0.208 0.00 0.216 0.00 0.223 0.00 0.231 0.00 0.238 0.00 0.245 0.00 0.252 0.00 0.259 0.00 0.265 0.00 0.271 0.00 0 .277 0.00 0. 283 0.00 Surf Area (sq. ft) 3240. 3265. 3281. 3306. 3323. 3348. 3373. 3390. 3415. 3517. 3611. 3715. 3820. 3925. 4023. 4131. 4240. 4350. 4451. 4563. 4676. 4790. 4905. 5011. 5128. 5246. 5365. 5475. 5596. 5718. 5841. 2.91 :.91 13230. 0.304 0.289 0.00 5954. 3.03 3. 03 13952. 0.320 0.295 0.00 6079. ::J .15 3.15 14E89. 0.337 0.301 0.00 620:J. ."l. 27 3. 2 7 154 41. 0.354 0.306 o.oc 6333. 3.38 3.38 16144. 0.371 0.312 0.00 6450. 3.50 3. 50 16926. 0.389 0.317 0.00 6579. 3.62 3.62 17723. 0.407 0.323 0.00 6709. 3.74 3.74 18536. 0.426 0.328 0.00 6840. 3. 8 6 3.86 19365. 0.445 0.333 0.00 6972. 3.97 3.97 20139. 0.462 0.338 0.00 7095. 4 . J 9 4.09 20998. 0.482 0.343 0.00 7229. 4. 21 4.21 21874. 0.502 0. 34 8 0.00 7364. 4. 33 4.33 22765. 0.523 0.353 0.00 7500. 4 . 4 4 4. 4 4 23597. 0.542 0.357 0.00 7626. 4.56 4.56 24521. 0.563 0.362 0.00 7764. 4.68 4.68 25461. 0.585 0.367 0.00 7904. 4. 8 0 4. 80 26418. 0.606 0. 371 0.00 8 0 4 4. 4.91 4. 91 27310. 0. 627 0.376 0.00 81 73. 5.03 5. 03 28299. 0.650 0.380 0.00 8316. :J. 15 5.15 29305. 0. 673 0.385 0.00 8459. 5.20 5.20 29730. 0.683 0.387 0.00 8519. 5.22 5.22 29900. 0.686 0.388 0.00 8543. 5.24 5.24 30072. 0.690 0.390 0. OD 8567. 5.25 5. 25 30157. O.E92 0.394 0.00 8579. 5.27 5.27 30329. 0. 696 0.399 0.00 8603. 5.29 5. 29 30501. 0.700 0. 406 0.00 8628. 5.31 5.31 30674. 0.704 0.413 0.00 8652. 5.33 5.33 30848. 0.708 0.421 0.00 8 67 6. 5.35 5.35 31021. 0.712 0.424 0.00 8700. :.:, . 36 5. 36 31108. 0. 714 0. 426 0.00 8712. 5. 48 5.48 32163. 0.738 0.441 0.00 8859. 5.60 5.60 33234. 0.763 0.454 0.00 9006. 5.72 5.72 34324. 0.788 0. 4 65 0.00 9154. 5.75 5. 75 34599. 0.794 0. 4 68 0.00 9191. 5.78 5.78 34875. 0.801 0.481 0.00 9229. 5.81 5.81 35153. 0.807 0.503 0.00 9266. 5.84 5.84 35431. 0.813 0.530 0.00 9303. 5.88 5.88 35805. 0.822 0.5€0 0.00 9353. 5.91 5.91 36086. 0.828 0.594 0.00 9391. 5. 94 5.94 36368. 0.835 0.630 0.00 9429. 5.97 5.97 36651. 0.841 0.668 0.00 9466. 6.00 6.00 36936. 0.848 0.709 0.00 9504. 6 .10 6.10 37893. 0.870 1.180 0.00 9630. 6.20 6. 20 38862. 0.892 2.030 0.00 9757. 6.30 6.30 39844. 0.915 3.130 0. 00 9885. 6.40 6.40 40839. 0.938 4.430 0.00 10014. 6.50 6.50 41847. 0.961 5.910 0.00 10143. 6.60 6.60 42868. 0.984 7.340 0.00 10273. 6. 70 6.70 43902. 1. 008 7.880 0.00 10404. 6.80 6.80 44949. 1. 032 8.380 0.00 10535. 6.90 6.90 46009. 1. 056 8.850 0.00 10667. 7.00 7.00 47082. 1. 081 9.290 0.00 10800. 7.10 7.10 48169. 1.106 9. 710 0.00 10934. 7.20 7.20 49269. 1.131 10 .110 0.00 11068. 7.30 7.30 50382. 1.157 10.500 0.00 11203. 7.40 7.40 51509. 1.182 10.870 0.00 11339. 7.50 7.50 52650. 1.209 11.230 0.00 11475. 7.60 7.60 53804. 1. 235 11.580 0.00 11612. 7.70 7.70 54972. 1.262 11. 920 0.00 11750. 7.80 7. 80 56154. 1.289 12.240 0.00 11889. 7.90 7.90 57350. 1.317 12.560 0.00 12028. 8.00 8.00 58560. 1 . 34 4 12.870 0.00 12168. Hyci 1 2 3 4 5 6 7 8 I:-iflow l. 99 2.05 1. 29 1. 18 1. 28 1. 37 1. 49 0.69 Oi;tflow Target * + * • + • -I C.87 ******* +****** ******* C-:ilc 1. 02 0.81 C.80 C.57 0.53 0.38 0.31 0. 29 ?eak Sr.age 6. 07 6.02 6.02 5.89 5.84 4.90 3.38 2.88 Route Time Series through Facility Elev 6.07 6.02 6.02 5.89 5. 84 4.90 3.38 2.88 SLorage ;C-..1.-Ft) (P..c-Ct) 37567. 0.862 37151. 0.853 37130. 0.852 35913. 0.824 35472. 0.814 27227. 16125. 13038. 0.625 0.370 0.299 Inflow Time Series File:devcombined.tsf Outflow Time Series File:rdout Inflow/Outflow Analysis Peak Inflow ~ischarge: Peak Outflow Discharge: Peak Reservoir Stage: Peak Reservoir Elev: 2.26 CFS at 6:00 on Jan 1.02 CFS at 16:00 on Oct 6. 07 Fl 6. 07 Ft 9 in 1990 6 in 1981 Peak Reservoir Storage: 37567. C·c.1.-Ft 0. 862 Ac-Fl Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---A~nual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFSi 0. 31c 0.337 a.sos 0.281 0.290 0.288 0. 371 0.333 0.336 0.322 0.299 0.573 0.316 0.256 0.306 0.299 0.325 0.265 0.355 0.280 0.315 0.300 0.313 0.381 0.287 0.269 0.362 0.300 0.249 0.312 0.263 0.376 23 14 4 42 37 38 11 17 15 21 31 6 22 47 27 32 20 45. 13 43 24 29 25 9 39 44 12 2/17/49 3/04/50 2/09/51 1/30/52 9/30/53 1/06/54 2/07/55 11/02/55 12/09/56 1/16/58 10/19/58 11/20/59 11/20/60 1/02/62 11/25/62 1/01/64 11/24/64 1/05/66 1/19/67 2/04/68 12/03/68 1/14/70 12/06/70 2/28/72 12/26/72 1/15/74 12/27/74 0:00 3:00 19:00 10:00 16:00 7:00 23:00 23:00 17: 00 21:00 8:00 22:00 16:00 23:00 15:00 20:00 9:00 18:00 17:00 0:00 21: 00 1:00 12:00 7:00 6:00 4:00 3:00 30 12/02/75 23:00 48 8/24/77 0:00 26 9/23/78 11:00 46 11/19/78 8:00 10 12/15/79 10:00 LcgPearson III Coefficients Mean= -0.462 StdDev= 0.149 Skew= 1.784 -----Flow Frequency Analysis------- --Peaks --Rank Return Prob (CFS) (ft) Period 1.02 6.07 1 89.50 0.989 0.848 6.03 2 32.13 0.969 0.815 6.02 3 19.58 0.949 0.805 6.02 4 14.08 0.929 0.680 5.98 5 10.99 0.909 0.573 5.89 6 9.0~ 0.889 0.533 5.84 7 7.64 0.869 0.467 5.74 8 6.63 0.849 0.381 5.06 9 5.86 0.829 0.376 4.90 10 5.24 0.809 0.371 4.80 11 4.75 0.789 0.362 4.56 12 4.34 0.769 0.355 4.38 13 3.99 0.749 0.337 0.336 0.334 0.333 0.331 0.329 0.325 0.322 0.316 0.316 0.315 0.313 0.312 0.306 0.304 0.300 0.300 0.299 0.299 3.95 3.93 3.88 3.86 3.81 3. 75 3.68 3.61 3.48 3. 4 7 3. 4 6 3. 41 3.38 3. 27 3.22 3.13 3.12 3. 11 3 .11 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 3. 70 3.44 3.22 3.03 2.85 2.70 2.56 2. 44 2.32 2.22 2 .13 2.04 1. 96 1. 89 1. 82 1. 7 5 1. 70 1. 64 1. 59 0. 729 0.709 0.690 0.670 0.650 0.630 0.610 0.590 0.570 0.550 0.530 0.510 0.490 0.470 0.450 0.430 0.410 0.390 0.370 0.292 36 11/21/SC 13:00 0.29E 3.06 33 1. 54 0.3SC 1. J2 !C/C6/8: 16: 00 0.293 3.0C 34 I. 4 9 0.330 0.331 18 l/CS/83 10:00 0.292 2.97 35 1. 4 .s 0.310 0.283 ·1 C 1/24/84 i2: 00 0.292 2. 96 36 I. 41 0. 291 0.3C4 £8 6/07/85 7:00 0.290 2.94 37 1. 37 0. 271 0. 4 67 8 1/18/86 22:00 0.288 2.89 38 1.33 0.251 0.533 7 11/24/86 7:00 0.287 2.88 39 1.30 0.231 0.282 41 1/14 /88 14:00 0.283 2.80 40 1.27 C. 211 0.230 49 L/05/88 18:00 0.282 2. 78 41 1. 24 0.191 0.680 5 l/09/90 11: 00 0.281 2. 75 42 I. 21 0 .1 71 0.815 3 11/24 /90 15:00 0.280 2.75 43 1.18 0.151 0.292 35 i/27 /92 19:00 0.269 2.53 44 I. 15 0 .131 0. 296 33 3/23/93 1:00 0.265 2. 4 3 45 1.12 0 .111 0.215 50 12/01/93 15:00 0.263 2. 41 46 1.10 0.091 0.329 19 12/27/94 6:00 0.256 2.28 47 1. 08 0. 071 0.848 2 2/09/96 2:00 0.249 2.16 48 1. 05 0.051 0.334 16 3 /19 / 97 14:00 0.230 1. 84 49 1. 03 0.031 0.293 34 10 /3 0 / 97 9:00 0.215 1. 61 50 1. 01 0. 011 Computed Peaks 1.15 6.09 100.00 0.990 Computed Peaks 0.918 6.04 50.00 0.980 Comput.ed Peaks 0. 7J3 6.01 25.00 0. 960 Compu:ed Peaks 0.543 5.86 10.00 0.900 Computed Peaks 0. 513 5.82 8.00 0.875 Computed Peaks 0. 431 5.40 5.00 0.800 Computed Peaks 0.314 3. 42 2.00 0.500 Computed Peak~ 0.267 2.48 1. 30 0.231 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CD? Exceedence Probability CFS '/; 0.014 344713 78.702 78. 702 21. 298 0.213E+OO 0.043 31026 7.084 85.785 14.215 0.142E+OO 0.071 17321 3.955 89.740 lJ.260 C.103E+OO 0.100 13468 3.075 92.815 7.185 0.719E-01 0.128 9871 2.254 95.068 4.932 0.493E-01 0.157 7 500 1. 712 96.781 3.219 0.322E-01 0.185 5127 1.171 97.951 2.049 0.205E-01 0.214 3442 o. 786 98.737 1. 263 0.126E-01 0.242 2255 0.515 99.252 0. 748 0.748E-02 0.271 1278 0. 292 99.544 0.456 0.456E-02 0.299 907 0.207 99. 751 0.249 0.249E-02 0.328 524 0 .120 99.870 0.130 0 .130E-02 0.356 246 0. 056 99.926 0.074 0.735E-03 0.385 179 0.041 99.967 0.033 0.326E-03 0.413 28 0. 006 99.974 0.026 0.263E-03 0.441 23 0.005 99.979 0.021 0.210E-03 0.470 47 0. 011 99.990 0.010 0.103E-03 0. 4 98 9 0.002 99.992 0.008 0.822E-04 0. 527 4 0.001 99.993 0.007 0. 731E-04 0.555 6 0.001 99.994 0.006 0.594E-04 0.584 7 0.002 99. 996 0.004 0.434E-04 0.612 2 0.000 99. 996 0.004 0.388E-04 0.641 0.000 99. 996 0.004 0.365E-04 0.669 2 0.000 99.997 0.003 0.320E-04 0.698 7 0.002 99.998 0.002 0.160E-04 0.726 1 0.000 99.999 0.001 0.137E-04 0.755 1 0.000 99.999 0.001 0.114E-04 0.783 0 0.000 99.999 0.001 0.114E-04 0.812 2 0.000 99.999 0.001 0.685E-05 0.840 0.000 100.000 0.000 0.457E-05 0.868 1 0.000 100.000 0.000 0.228E-05 0.897 0 0.000 100.000 0.000 0.228E-05 0.925 0 0.000 100.000 0.000 0. 228E-05 Cl. 9S4 C.982 1.0: C 0.000 0.000 0.000 180.000 lC0.000 lC0.000 0.000 0.000 o. Joe, '~------------------- s .._::\~- •."-. \ ~ "-... " R 11 • ~ i ~ N ~ ~ s s 10 ., 10 ., Duratio~ Comparison Anaylsis Base File: predevcombined.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS __ ____ Probeb*ly Ea:OOOOllllee 0.228E-:JS 0.228c-0S 0.228c-C5 10 ·1 -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New './:Change Probability Base 0.396 0.36E-03 0.29E-03 -19.2 I 0.36E-03 0. 396 0.440 0.22E-03 0.21E-03 -6.1 I 0.22E-03 0. 4 40 0.484 0 .14E-03 0.94E-04 -33.9 I 0.14E-03 0. 484 0.528 0.84E-04 0.73E-04 -13.5 I 0.84E-04 0.528 0.571 0.64E-04 0.53E-04 -17.9 I 0.64E-04 0. 571 0.615 0.39E-04 0.39E-04 0.0 I 0.39E-04 0.615 0.659 0.25£-04 0.34E-04 36.4 I 0.25E-04 0.659 0.703 0.21£-04 0.16£-04 -22.2 I 0. 21E-04 0.703 0.746 0.14E-04 0.14E-04 0.0 I 0.14E-04 0.746 0.790 0.14E-04 0. llE-04 -16. 7 I 0.14E-04 0.790 0.834 0.14E-04 0.46E-05 -66.7 I 0.14E-04 0.834 0.878 0.68E-05 0.23E-05 -66.7 I 0.68E-05 0.878 0. 921 0.46E-05 0.23E-05 -50.0 I 0.46E-05 0.921 0. 965 0.23E-05 0.23E-05 0. 0 I 0.23E-05 0. 965 Maximum positive excursion= 0.083 cfs ( 8.9%) occurring at 0.936 cfs on the Base Data:predevcombined.tsf and at 1.02 cfs on the New Data:rdout.tsf Maximum negative excursion= 0.096 cfs (-11.3%) occurring at 0.846 cfs on the Base Data:predevcombined.tsf and at 0.750 cfs on the New Data:rdout.tsf New {Change 0.381 -3.9 0. 433 -1.6 0. 459 -5.2 0. 4 93 -6.6 0.534 -6.5 0.626 ] . 8 0.679 3.1 0.693 -1. 4 0.750 0. 5 0.750 -5.0 0.750 -10.0 0. 813 -7.3 0.847 -8.0 1. 02 5.7 nxu, du, lafl)Ol ~u· 10' APPENDIXB Geotechnical Reports Earth Solutions NW, LLC Earth Solutions NWLLc Geotechnical Engineering Geology Environmental Scientists Construction Monitoring GEOTECHNICAL ENGINEERING STUDY PROPOSED ROSA PLAT 2724 BENSON ROAD SOUTH RENTON, WASHINGTON ES-2972 PREPARED FOR CONNER HOMES GROUP, LLC c/o WESTPAC DEVELOPMENT September 10, 2013 Kyle R. Campbell, P.E. Principal GEOTECHNICAL ENGINEERING STUDY PROPOSED ROSA PLAT 2724 BENSON ROAD SOUTH RENTON, WASHINGTON ES-2972 Earth Solutions NW, LLC 1805 -136111 Pl. Northeast, Suite 201 Bellevue, Washington 98005 Ph: 425-449-4704 Fax: 425-449-4711 Toll Free: 866-336-8710 Important Inf ormalion About Your Geotechnical Engineering Report Geotechnical Services Ara Performed for Specific Purposes, Pars•, and Projects Geotechnical engineers stlllciure their services to meet the specific needs of their clients. A geotechnical engineering study conducted for a civil engi- neer may not fulfill the needs of a construction contractor or even another civil engineer. Because each geolechnical engineering study is unique, each geotechnical engineering report is unique, prepared solelyfor the client. No one except ycu should rely on your geotechnical engineering report without first conferring with the geotechnical engineer who prepared it. And no one -not even you-should apply the report for any purpose or project except the one originally contemplated. 1111d the ~ Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only. A Geol8cllllcal Enllnll":r' Is Based on A u-.. Sat al Pl'ljlct Factors Geotechnical engineers consider a number of unique, project-specific fac- tors when establishing the scope of a study. Typical factors include: the client's goals, objectives, and risk management preferences; the general nalure of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates oth- erwise, do not rely on a geotechnical engineering report that was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse, • elevation, configuration. location, orientation, or weight of the proposed structure, • composition of the design team, or • project ownership. As a general rule, always inform your geotectmical engineer of project changes----€ven minor ones-and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed. Subsurface COndltions can Cllanga A geotechnical engineering report is based on conditions that existed at the time the study was pertormed. Do not rely on a geotechnical engineer- ing reportwhose adequacy may have been affected by: the passage of time; by man-made events. such as construction on or adjacent to the site; or by natural events, such as floods, earthquakes, or groundwater fluctua- tions. Alw.iy.s contact the geotechnical engineer before applying the report to determine tt tt is still reliable. A minor amount of additional testing or analysis could prevent major problems. Most Geotechnlcal FlndingS Ar• Prllealolal Oplnllns Stte exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are 1aken. Geotechnical engi- neers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface condttions may differ---rometimes signmcanfty- from those indicated in your report. Retaining the geotechnical engineer wllo developed your report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions. A Report's RIICtllllllellda Are Not Flnal Do not overrely on the construction recommendations included in your report. Those recommendations are not final, because geotechnical engi- neers develop them principally lrom judgment and opinion. Geolechnical engineers can finalize their recommendations only by observing actual subsurtace conditions revealed during construction. The geotechnical engineer who developed your report cannot assume responsibi/il'j or liability for the report's recommendations if that engineer does not perform construe/ion observation. A Geotechnical Engineel'ing Report Is M]act to Misinterpretation Other design team members' misinterpretation of geotechnical engineering reports has resulted in costly problems. Lower that risk by having your geo- technical engineer confer with appropriate members of the design team after submitting the report. Also retain your geotechnical engineer to review perti- nent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering report. Reduce that risk by having your geotechnical engineer participate in prebid and preconstruction conferences, and by providing construction observation. Do Not R•aw the Engineer's Logs Geotechnical engineers prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize thiJt separating logs from the report can elevate risk. GiVe Contracturs a Cmnlllete Report and Guldaoca Some owners and design professionals mistakenly believe they can make contractors liabfe for unanticipated subsurtace conditions by limtting what they provide for bid preparation. To help prevent costly problems, give con- tractors the complete geotechnical engineering report, bu/preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with the geotechnical engineer who prepared the report (a modest fee may be required) and/or to conduct additional study to obtain the specific types of information they need or prefer. A prebid conference can also be valuable. Be sure contrac- tors have sufficient time to pertorm additional study. Only then might you be in a posttion to give contractors the best infonmation available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipaled condttions. Read Rasp111Biblilr Pl'ovlsions Closely Some clients. design professionals, and contractors do not recognize that geotechnical engineering is far less exact than other engineering disci- plines. This lack of understanding has created unrealistic expectations that have led to disappointments, claims, and disputes. To help reduce the risk of such outcomes, geotechnical engineers commonly include a variety of explanatory provisions in their reports. Sometimes labeled 'limitations" many of these provisions indicate where geotechnical engineers' responsi- bilities begin and end, to help others recognize their own responsibiltties and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenviro1111enta1 Concerns Are Not Covered The equipment, techniques, and personnel used to pertorm a geoenviron- mental study differ significantly from those used to pertorm a geotechnical study. For that reason. a geotechnical engineering report does not usually relate any geoenvironmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated environmental problems have led to numerous project failures. If you have not yet obtained your own geoen- vironmental information. ask your geotechnical consultant for risk man- agement guidance. Do not rely on an environmental report prepared for someone else. Obtain Professional Assisladt:e To Deal with Mold Diverse strategies can be applied during building design, construction, operation, and maintenance to prevent significant amounts of mold from growing on indoor surtaces. To be effective, all such strategies should be devised for the express purpose of mold prevention, integrated into a com- prehensive plan, and executed With diligent oversight by a professional mold prevention consultant. Because just a small amount of water or moisture can lead to the development of severe mold infestations, a num- ber of mold prevention strategies focus on keeping building surtaces dry. While groundwater, water infiltration, and similar issues may have been addressed as part of Ille geotechnical engineering study whose findings are conveyed in-this report, the· geotechnical engineer in charge of this project is not a mold prevention consultant; none afUle ,ervices p,r- farm,d In t:onnecllon with Ule geotet:hnlcal engineer's study were dnigned or conducted tor the purpose of mold preven- tion. Proper Implementation of U,11 fllt:DRl1111111dations ,:omn,yed in this report will not of ttseN be sutfit:/fHlt to prewnt mold from growing in or on 1h11 stmcture Involved. Rely, 111 Your ASFE--Memller Geoblcllnclal · Englnaer for Addlliui181 Anllllllcl Membership in ASFE/The Best People on Earth exposes geotechnicat engineers to a wide array of risk management techniques that can be of genuine benerrt for everyone involved with a construction project. Confer with you ASFE-member geotechnical engineer for more infomnation. 8811 Colesville Road/Suilll 6106, Silver Spring, MD 20910 Telephone: 301/565-2733 Facsimile: 301/589-2017 e-mail: info@asfe.org www.asfe.org Gapynght 20041/y ASFE. Inc. OUpllcat/on, reproducffon, or copying ol tl!ls docJJ,,,.., In wflo/8 or In part. by any means whatsoe1111r, is striclly prollll>ited, 8X£8J11 wilf1 ASFE's spocitlc written ponnission. Excerpting, quoting. or otherwis, 6JllncJJng wording tram lflis docJJment is perm/llet1 only wftl! the BXf)r&SS written parmlssion of ASFE, 111d only 111< purposes of scholarly resean:h or book l'Bviflw. Only members of ASFE may us, thW document as a complement to or as an element of a geol6chnfcal m,gmeering ,sport Any other firm, lndlvfdual, or other entity that so uses this document without belna an ASFE membsr could bs cammnt;ng negligent or lnt8fTtionaf (fraudulent) misrepr&srmtation. IIGEf\06045.0M September 10, 2013 ES-2972 Conner Homes Group, LLC c/o WestPac Development 7449 West Mercer Way Mercer Island, Washington Attention: Mr. Peter O'Kane Dear Mr. O'Kane: Earth Solutions NW LLC • Ceotechnical Engineering • Construction Monitoring • Environmenlal Sciences Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Geotechnical Engineering Study, Proposed Rosa Plat, 2724 Benson Road South, Renton, Washington". Based on the results of the geotechnical investigation, the proposed residential development is feasible from a geotechnical standpoint. The soil underlying the site consists predominantly of native weathered and unweathered glacial till deposits. The proposed residential structures can be supported on conventional foundations bearing on competent native soils generally encountered at depths of one to two feet below existing grade or structural fill placed as part of the site grading activities. Recommendations for foundation design, earthwork, and other pertinent geotechnical recommendations are provided in this report. A site plan was not available at the time of this report. If you have any questions regarding the content of this geotechnical engineering study, please contact us. Sincerely, EARTH SOLUTIONS NW, LLC . ()'I). ~0 Watson, E.1.-d ineer 1805 -136th Place N.E., Suite 201 • Bellevue, WA 98005 • (4251 449-4704 • FAX 1425) 449-4711 TABLE OF CONTENTS ES-2972 PAGE INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . ... 1 General .................................................................... ...... 1 Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Surface............ .. . . .. ... . .. ... ... ... . .. .. .... ... ... ... ... ... ... ... ...... ... . .. . 1 Subsurface....................................................................... 2 Geologic Setting....................................................... 2 Groundwater...................................................................... 2 DISCUSSION AND RECOMMENDATIONS ....................................... 2 General... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. . .. . .. . .. . . . . .. . . . . . . . . . . . . . . . . . . . 2 Site Preparation and Earthwork............................................ 3 Temporary Erosion Control....................................... 3 In-situ Soils .............................................................. 3 Structural Fill Placement........................................... 3 Subgrade Preparation............................................... 4 Foundations..................................................................... 4 Slab-on-Grade Floors......................................................... 5 Seismic Considerations......................... . .. . .. .. .. . . . .. . . .. . . . . . .. . . .. .. 5 Excavations and Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 6 Utility Trench Backfill......................................................... 6 Drainage........................................................................... 6 Retaining Wall .................................................................. 7 Pavement Sections............................................................ 7 LIMITATIONS.............................................................................. 8 Additional Services............................................................ 8 Earth Solutions NW. LLC GRAPHICS Plate 1 Plate 2 Plate 3 APPENDICES Appendix A Appendix B TABLE OF CONTENTS Cont'd ES-2972 Vicinity Map Test Pit Location Plan Typical Footing Drain Detail Subsurface Exploration Test Pit Logs Laboratory Test Results Grain Size Distribution Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED ROSA PLAT 2724 BENSON ROAD SOUTH RENTON, WASHINGTON ES-2972 INTRODUCTION General This geotechnical engineering study was prepared for the proposed residential development to be constructed off of Benson Road South Renton, Washington. The approximate location of the subject property is illustrated on the Vicinity Map (Plate 1 ). The purpose of this study was to develop geotechnical recommendations for the proposed project. The scope of services for completing this geotechnical engineering study included the following: • Subsurface exploration consisting of observing, logging and sampling four test pits excavated within accessible areas of the development envelope; • Engineering analysis; and, • Preparation of this report. Project Description The subject site is located southeast of the intersection Benson Road South and South 27th Street in Renton, Washington. The subject site consists of four adjoining tax parcels totaling approximately 4.2 acres. Existing structures onsite include two houses. A cursory review of an available geologic map indicates the site is underlain by Vashon subglacial till (Qvt). We understand the existing structures will be removed and the site will be redeveloped into residential lots, access roads, and associated utility improvements Surface The existing vegetation consists of tree cover concentrated near the northwest corner of the site and a large grass field for the remainder of the site. Site topography descends northwest at a moderate slope, with approximately forty feet of elevation change across the site. The topography surrounding the two existing single-family structures suggest fills of up to four feet were placed during construction of the buildings. Earth Solutions W>/, LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 Subsurface ES-2972 Page2 An ESNW representative observed, logged and sampled four test pits excavated at the site for purposes of assessing soil and groundwater conditions. The approximate locations of the test pits are illustrated on the Test Pit Location Plan (Plate 2). Please refer to the test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Topsoil was encountered to depths of approximately six inches. Fill was encountered at test pit location TP-4 to a depth of about one foot below existing grade. Chunks of old concrete foundation were also observed in fill areas at TP-4. Fill consisted primarily of medium dense silty sand with varying amounts of gravel (Unified Soil Classification SM). Native soils underlying the topsoil and fill were comprised primarily of dense to very dense silty sand with gravel (SM) associated with weathered and unweathered glacial deposits. Soil relative density generally increased with depth. In general, dense conditions were encountered at depths up to three and one-half feet below existing grades. Geologic Setting The geologic map of the area identifies glacial till (Qvt) deposits throughout the site and surrounding area. Based on the results of the subsurface investigation, the soils observed at the test sites are generally consistent with the glacial till. Groundwater No seepage was observed at test pit locations (August 2013). However, groundwater seepage should be expected in site excavations, given the observed soil conditions. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. DISCUSSION AND RECOMMENDATIONS General Based on the results of our study, the residential development on the subject site is feasible from a geotechnical standpoint. The proposed residential structures can be supported on competent native soil generally encountered at depth of one to two feet below existing grades or on structural fill placed as part of the site grading activities. Where fill areas are proposed, compaction of the existing fill soils to structural fill specifications described later in this study will be necessary. This study has been prepared for the exclusive use of Conner Homes Group, LLC, and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Earth Solutions NW, LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 Site Preparation and Earthwork ES-2972 Page 3 Site preparation activities will likely include removing the existing structure and associated improvements from the development envelope, establishing clearing limits and installing temporary erosion control measures. The primary geotechnical considerations during the proposed site preparation and earthwork activities will involve the overall cut and fill activities, structural fill placement and compaction, underground utility installations, and final building and pavement area subgrade preparation. We anticipate the mass grading will utilize a balanced approach, with cut soils used as structural fill elsewhere on-site. Temporary Erosion Control Temporary erosion control measures should include, at a minimum, silt fencing placed along the downslope perimeter of the construction envelope, and a construction entrance consisting of quarry spalls to minimize off-site soil tracking and to provide a firm surface. Surface water must not be allowed to flow over, or collect above, temporary or permanent slopes. Interceptor drains or swales should be considered for controlling surface water flow patterns. ESNW should observe the erosion control measures, and provide supplement recommendations for minimizing erosion during construction. In-situ Soils From a geotechnical standpoint, the silty sand deposits encountered at the test pit locations are generally suitable for use as structural fill provided the soil moisture content at the time of grading allows compaction to the levels specified below. The moisture sensitivity of the silty sand deposits anticipated to be exposed during grading activities can generally be characterized as moderate to high. Due to the moisture sensitive nature of the silty sand soil, successful use of the soil will largely be dictated by the moisture content at the time of placement and compaction. If the on-site soils cannot be successfully compacted, the use of an imported soil may be necessary. Imported soil intended for use as structural fill should consist of a well graded granular soil with a maximum aggregate grain size of six inches, and a moisture content that is at or near the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of 5 percent or less defined as the percent passing the #200 sieve, based on the minus three-quarter inch fraction. Structural Fill Placement In general, areas to receive structural fill should be sufficiently stripped of organic matter and other deleterious material. Overstripping of the site and proposed fill surfaces should be avoided. ESNW should observe cleared and stripped areas of the site prior to structural fill placement. Earth Solutions NW, LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 ES-2972 Page4 Structural fill is defined as compacted soil placed in foundation, slab-on-grade, and onsite roadway areas. Fills placed to construct permanent slopes and throughout rockery, retaining wall, and utility trench backfill areas are also considered structural fill. Soils placed in structural areas should be placed in maximum 12 inch lifts and compacted to a relative compaction of 90 percent, based on the maximum dry density as determined by the Modified Proctor Method (ASTM D-1557-02). In pavement areas, the upper 12 inches of the structural fill should be compacted to a relative compaction of at least 95 percent. City, county, or other jurisdiction compaction requirements may supercede the above recommendations in right-of-way areas. Subgrade Preparation Following site stripping and removal of the existing structural improvements, cuts and fills will be completed to establish the proposed subgrade levels throughout the site. Existing fill placed during the construction of the existing structures may need to be compacted to the requirements of structural fill, depending on field conditions. ESNW should observe the subgrade during the initial site preparation activities to confirm soil conditions and to provide supplemental recommendations for subgrade preparation, if necessary. The process of removing the existing building structure may produce voids where the old foundations are removed, and where basement or crawl space areas may have been present. Thorough restoration of voids from old foundation and basement areas must be completed as part of the overall subgrade and building pad preparation activities. The following guidelines for preparing the building subgrade areas should be incorporated into the final design: • Where voids and related demolition disturbances extend below the planned subgrade level, restoration of these areas should be completed. Structural fill should be used to restore voids or unstable areas resulting from the existing building removal. • Re-compact or overexcavate and replace areas of existing fill (if present) exposed at the building subgrade elevation. ESNW should confirm subgrade conditions and the required level of re-compaction or overexcavation and replacement during the site preparation activities. Overexcavations should extend to competent (medium dense) native soils and replaced with structural fill. • ESNW should confirm overall suitability of the prepared subgrade areas following the site work activities. Foundations The proposed residential structures can be supported on conventional spread and continuous footings bearing on competent native soil or structural fill. We anticipate competent native soil suitable for support of foundations will generally be encountered at depths of one to two feet below existing grades. Building pad fill areas should be compacted to the specifications of structural fill previously described in this report. Where loose or unsuitable soil conditions are encountered at foundation subgrade elevations, compaction of the soils to the specifications of structural fill, or overexcavation and replacement with structural fill may be necessary. Eanh Solutions r-rw. LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 For design the following parameters can be used for the foundation design: • Allowable soil bearing capacity • Passive earth pressure • Coefficient of friction 2,500 psf 350 pcf 0.40 ES-2972 Page 5 The passive earth pressure value provided above assumes the foundations are backfilled with structural fill. A factor-of-safety of 1.5 has been applied to these passive resistance and friction values. For short term wind and seismic loading, a one-third increase in the allowable soil bearing capacity can be assumed. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of approximately one-half of an inch. The majority of the settlements should occur during construction, as dead loads are applied. Slab-On-Grade Floors Slab-on-grade floors for residential structures should be supported on competent native soil or structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free draining crushed rock or gravel should be placed below the slab. The free draining material should have a fines content of 5 percent or less (percent passing the #200 sieve, based on the minus three-quarter inch fraction). In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If a vapor barrier is used it should consist of a material specifically designed for that use and be installed in accordance with the manufacturer's specifications. Seismic Considerations The 2009 International Building Code specifies several soil profiles that are used as a basis for seismic design of structures. If the project will be permitted using the 2009 IBC, based on the soil conditions observed at the test sites, Site Class D, from table 1613.5.2, should be used for design. The 2012 IBC recognizes ASCE for seismic site class definitions. If the project will be permitted under the 2012 IBC, in accordance with Table 20.3-1 of ASCE, Minimum Design Loads for Buildings and Other Structures, Site Class D, should be used for design. In our opinion, liquefaction susceptibility at this site is low. The relative density of the site soils and the absence of a uniform, shallow groundwater table is the primary basis for this designation. Earth Solutions t-lW, LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 Excavations and Slopes ES-2972 Page 6 The Federal and state Occupation Safety and Health Administration (OSHA/WISHA) classifies soils in terms of minimum safe slope inclinations. Based on the soil conditions encountered during our fieldwork, fill, weathered native soil and where groundwater is exposed would be classified by OSHA/WISHA as Type C. Temporary slopes over four feet in height in Type C soils should be sloped no steeper than 1.5H:1V (Horizontal:Vertical). Dense glacial till soils would be classified by OSHA/WISHA as Type A. Temporary slopes over four feet in height in Type A soils should be sloped no steeper than 0.75H:1V (Horizontal:Vertical). Temporary slopes steeper than the OSHA/WISHA guidelines detailed above may be acceptable depending on the actual conditions exposed during grading activities. ESNW should observe temporary and permanent slopes to confirm that the inclination is appropriate for the soil type exposed, and to provide additional grading recommendations, as necessary. If temporary slopes cannot be constructed in accordance with OSHA/WISHA guidelines, temporary shoring may be necessary. Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with an appropriate species of vegetation to enhance stability and to minimize erosion. Utility Support and Trench Backfill In our opinion, the soils observed at the test pit locations are generally suitable for support of utilities. Excessively loose, organic, or otherwise unsuitable soils encountered in the trench excavations should not be used for supporting utilities. In general, the on-site soils observed at the test pit locations should be suitable for use as structural backfill in the utility trench excavations, provided the soil is at or near the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soils may be necessary at some locations prior to use as structural fill. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable specifications of the County or other applicable jurisdiction or agency. Drainage Groundwater seepage was not encountered at the time of our fieldwork (August 2013). However, the presence of perched groundwater seepage should be anticipated during site excavations, particularly in the late fall, winter, spring and early summer months. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve interceptor trenches and sumps, as necessary. In our opinion, the proposed residential structures should incorporate footing drains around the outside perimeter of the foundations. A typical footing drain detail is provided on Plate 3 of this report. Surface grades adjacent to structures should slope away from the structures at a gradient of at least 2 percent. Earth Solutions WV, LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 Retaining Walls ES-2972 Page 7 Retaining walls should be designed to resist earth pressures and applicable surcharge loads. The following parameters can be used for preliminary retaining wall design: • Active earth pressure (yielding condition) 35 pcf (equivalent fluid) • At-rest earth pressure (restrained condition) 55 pcf • Traffic surcharge (passenger vehicles) 70 psf (rectangular distribution) • Passive pressure 250 pcf (equivalent fluid) • Coefficient of friction 0.40 • Seismic surcharge 6H* (yielding condition) 14H* (restrained condition) 'Where H equals the retained height Additional surcharge loading from foundations, sloped backfill, or other loading should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. ESNW should review any retaining wall designs to verify that appropriate earth pressure values have been incorporated into design and to provide additional recommendations. Retaining walls should be backfilled with free draining material that extends along the height of the wall, and a distance of at least 18 inches behind the wall. The upper one foot of the wall backfill can consist of a less permeable (surface seal) soil, if desired. A rigid, perforated drain pipe should be placed along the base of the wall, and connected to an approved discharge location. Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications previously detailed in this report. It is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas containing unsuitable or yielding subgrade conditions will require remedial measures such as overexcavation and thicker crushed rock or structural fill sections prior to pavement. For lightly loaded pavement areas subjected primarily to passenger vehicles, the following preliminary pavement sections can be considered: Earth Solutions ~. LLC Conner Homes Group, LLC c/o WestPac Development September 10, 2013 ES-2972 Page 8 • Two inches of hot mix asphalt (HMA) placed over four inches of crushed rock base (CRB), or; • Two inches of HMA placed over three inches of asphalt treated base (ATB). For relatively high volume, heavily loaded pavements subjected to occasional truck traffic, the following preliminary pavement sections can be considered: • Three inches of HMA placed over six inches of CRB, or; • Three inches of HMA placed over four inches of ATB. The HMA, ATB and CRB materials should conform to WSDOT specifications. All soil base material should be compacted to at least 95 percent of the maximum dry density. Final pavement design recommendations can be provided once final traffic loading has been determined. City of Renton road standards may supersede the recommendations provided in this report. LIMITATIONS The recommendations and conclusions provided in this geotechnical engineering study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test sites may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if variations are encountered. Additional Services ESNW should have an opportunity to review the final design with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. Earth Solutions NW, LLC ·~ ••• (.:··.-:. \ !J:1. "' )i~ ... . ·, . • ' J,. J ~- at ~ .......... -·---.;---,, . C " ~ . l ., - "' J '' ,., :-1!'• ~ . ----·-M ___ }1_11 Reference King County. Washington Map 656 By The Thomas Guide Rand McNally 32nd Edition [ OTE: This plate may contain areas of color. ESNVV cannot be espo_nsible for any subsequent misint_erpretation of the information esult1ng from black & white reproductions of this plate. --------------------- Drwn. GLS Vicinity Map Rosa Property Renton, Washington Date 08/29/2013 Proj. No. Checked sew Date Aug. 2013 Plate ., 2972 ~. ! : I i • I I ' --, '\.. s:,,,,-,.;1 'T.'il(/ I I I ! ' : e \ "· I 1:121:1t s:s1-;-1 .. --•-I I ! I --\1: I TP-1 1 ·: 'Y)_ LEGEND TP-1-!-Approximate Location of I ESNW Test Pit, Proj. No. ES-2972, Aug. 2013 ---1 I I Subject Site '--- 4 Proposed Lot Number NOTE: The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the approximate test locations relative to the approximate locations of existing and / or proposed site features. The information illustrated is largely based on data provided by the client al the time of our study. ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. __ J -•- ITP-2 . S. 28TI I SJ. i :sl r, ,'/1 21 I ['.1 1(51 ____ -I ' ""TP-4 !-I I h I I ', I I I 11 \ "" : --16---1 J!_ 12 \\ • ', I I I I TP-3 ~-----'-------· Not -To -Scale Test Pit Location Plan Rosa Property Renton, Washington Drwn. GLS Date 08/29/2013 Proj. No. 2972 Checked sew Date Aug. 2013 Plate 2 Slope ... 2" (Min.) Perforated Rigid Drain Pipe (Surround with 1" Rock) NOTES: • Do NOT tie roof downspouts to Footing Drain. • Surface Seal to consist of 12" of less permeable, suitable soil. Slope away from building. LEGEND: Surface Seal; native soil or other low permeability material. 1" Drain Rock SCHEMATIC ONLY-NOTTO SCALE NOT A CONSTRUCTION DRAWING • Drwn. GLS FOOTING DRAIN DETAIL Rosa Property Renton, Washington Date 09/10/2013 Proj. No. 2972 Checked sew Date Sept. 2013 Plate 3 Appendix A Subsurface Exploration ES-2972 The subsurface conditions at the site were explored by excavating four test pits at the approximate locations illustrated on Plate 2 of this report. The test pit logs are provided in this Appendix. The subsurface exploration was completed in August 28, 2013. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. Earth Solutions NW, LLC Earth Solutions NWLLc SOIL CLASSIFICATION CHART MAJOR DIVISIONS SYMBOLS TYPICAL GRAPH LETTER DESCRIPTIONS COARSE GRAINED SOILS MORE THAN 50% OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE FINE GRAINED SOILS MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE GRAVEL AND GRAVELLY SOILS MORE THAN 50% OF COARSE FRACTION RETAINEO ON NO. 4 SIEVE SAND AND SANDY SOILS CLEAN GRAVELS (LITTLE OR NO FINES) GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINES) CLEAN SANDS (LITTLE OR NO FINES) SANDS WITH MORE THAN 50% FINES OF COARSE FRACTION PASSING ON NO. 4 SIEVE (APPRECIABLE SILTS AND CLAYS SILTS AND CLAYS AMOUNT OF FINES) UQUIOUMIT LESSTHAN50 UQUIOUMIT GREATER THAN 50 HIGHLY ORGANIC SOILS GW WELL-GRADED GRAVELS, GRAVEL- SAND MIXTURES, LITTLE OR NO FINES POORLY-GRADED GRAVELS, GP GRAVEL-SAND MIX11JRES, LITTLE OR NO FINES GM SIL TY GRAVELS, GRAVEL -SAND - SILT MIX11JRES GC CLAVEY GRAVELS, GRAVEL -SANO- CLA V MIXTURES SW WELL-GRADED SANDS, GRAVELL V SANOS, LITTLE OR NO FINES SP POORLY-GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES SM SIL TY SANDS, SAND -SILT MIXTURES SC CLAYEY SANDS, SAND-CLAY MIXTURES INORGANIC SIL TS ANO VERY FINE ML SANDS, ROCK FLOUR, SIL TY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PlASTICITY INORGANIC CLAYS OF LOW TO CL MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SIL TS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SANO OR SILTY SOILS CH INORGANIC CLAYS OF HIGH PLASTICITY OH ORGANIC CLAYS OF MEOIUMTO HIGH PLASTICITY, ORGANIC SILTS PT PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. • Earth Solutions NW TEST PIT NUMBER TP-1 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Conner Homes Grou.Q -PROJECT NAME Rosa Propertv -·--- PROJECT NUMBER 2972 PROJECT LOCATION ~ Washington ------ DATE STARTED 8128/13 COMPLETED 8128/13 GROUND ELEVATION 435 ft TEST PIT SIZE ---------------- EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION -----·-------·-·-------------· ---· LOGGED BY sew CHECKED BY sew AT END OF EXCAVATION - NOTES Depth of Topsoil & Sod 6": forest duff AFTER EXCAVATION - w 0.. 0 :,: ~ffi r,; ~8 frig wm TESTS c_i MATERIAL DESCRIPTION _,::; <Ji ~_, Cl 0..::, ::i ::; z C) < ti) 0 •ps1 ~~ 0.5 TOPSOIL, scattered roots 4~,§ Tan silty SAND with gravel, medium dense, damp - SM -partially cemented --MC=6.30% 3.0 432.0 ------- Gray silty SANO with gravel, dense, moist - MC=9.40% -becomes very dense _L_ SM -scattered cobbles . ~ >-. MC=S.80% a_s 426.5 Test pit tenninated at 8.5 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 8.5 feet. • Earth Solutions NW TEST PIT NUMBER TP-2 1805136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone; 425-284-3300 CLIENT Conner Homes Group ""··----PROJECT NAME Rosa Property . ··---·------ PROJECT NUMBER 2972 PROJECT LOCATION Renton, Washington --·--,------ DA TE STARTED 8128/13 COMPLETED 8128113 '" ·-·. GROUND ELEVATION 453 ft TEST PIT SIZE ------ EXCAVATION CONTRACTOR J'!'!!_ Excavatinn GROUND WATER LEVELS: EXCAVATION METHOD ---... -·-----· ---ATTIME OF EXCAVATION -··------------.. -----------. LOGGED BY sew CHECKED BY sew AT END OF EXCAVATION ---- NOTES Depth of Topsoil & Sod 6": grass AFTER EXCAVATION -- w n. 0 ~g ~ffi ui il:8 wm TESTS cj MATERIAL DESCRIPTION ...J::i: ui ~_, 0 a.::, :; ~z (!I Cl) 0 TPS '' TOPSOIL, scattered roots 0.5 452.5 L Brown silty SAND with gravel, medium dense, damp SM -becomes dense C . MC=7.20% L . ~ 3.0 450.0 ---Gray sity SAND with gravel, dense, moist -<1cattered cobbles L-2..... SM C . . C MC= 10.40% 8.0 #5.0 Test pit terminated at 8.0 feet below existing grade. No groundwater enoountered during excavation. Bottom of test pit al 8.0 feel. • Earth Solutions NW TEST PIT NUMBER TP-3 1805136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Conner Homes GrouJ:!i PROJECT NAME Rosa Pro~ertv - PROJECT NUMBER 2972 -PROJECT LOCATION Renton Was~!ngton -----------• :c::c~--==----·----C....-. DATE STARTED 8128113 COMPLETED 8128/13 GROUND ELEVATION 451 ft TEST PIT SIZE ------ EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION ------------.-----------~- LOGGED BY sew CHECKED BY sew __ -~-AT END OF EXCAVATION ---------- NOTES De~th ofTo~soil & Sod 6": thick grass AFTER EXCAVATION - w n. u :,:: ~ffi c6 j: Cl ~g wm 0 _,::. TESTS "! ~g MATERIAL DESCRIPTION 0 n.::, ::!:z ::, Cl i'i 0 "PSI ~· •, ' 9.5 TOPSOIL, roots 450.5 ------. --·--· Brown silty SANO with gravel, medium dense; damp " SM f-- 3.0 -becomes moist 446.0 r -MC= 12.10% ~ -Gray silty SAND with gravel, dense, moist -partially cemented ~---scattered cobbles SM r . -becomes very dense . MC= 9.20% 7.5 443.5 Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 7.5 feet. • Earth Solutions NW TEST PIT NUMBER TP-4 1805136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Conner Homes Group _____ ··-·· PROJECT NAME Rosa Proi!!!rlv PROJECT NUMBER 2972 PROJECT LOCATION Renton" Washington _ ···-----__ ·---··---· -----------------·--------------... ------·-------~_:.,;__ DATE STARTED 8128113 COMPLETED 8128/13 GROUND ELEVATION 45011 TEST PIT SIZE ·-- EXCAVATION CONTRACTOR NW Excayatlng GROUND WATER LEVELS: EXCAVATION METI-IOD AT TIME OF EXCAVATION ---. ---------------·----·---------· ------ LOGGED BY sew CHECKED BY sew AT END OF EXCAVATION - NOTES _Depth of Topsoil & Sod 6": grass -----AFTER EXCAVATION ----_,, ____ -----·--------------- w :,: ~ ffi en u :i: (!) ~g wlD TESTS u n.o MATERIAL DESCRIPTION _,~ cn ~_, 0 n.:::) ::i ~z (!) V) 0 SM (Conctete obstruction -moved excavation 3' west) Brown silty SAND, medium dense, moist (Fill}, concrete chunks a -1.0 449.0 Brown silty SAND with gravel, medium dense, moist -MC= 8.80% SM --~~ 447.0 G,ay silty SAND with gravel. dense, moist --MC= 11.80% -partially cemented __L SM -scattered cobbles --becomes very dense -- MC= 10.50% 7.5 442,5 Test pit temninated at 7.5 feet below existing grade. No groundwater encounterad during excavation. Bottom of test pit at 7.5 feet. AppendixB Laboratory Test Results ES-2972 Earth Solutions NW, LLC • Earth Solutions NW GRAIN SIZE DISTRIBUTION 1805 -136th Place N.E., Suite 201 Bellevue, WA 98005 . Telephone: 425-284-3300 CLIENT Conner Homes GrOUQ LLC PROJECT NAME Rosa PROJECT NUMBER ES..2972 PROJECT LOCATION Renton U.S. SIEVE OPENING IN INCH~S I U.S. SI.VE NUMBERS I HYDROMETER 6 4 3 2 1 6 1 1123/B 3 4 6 B10 1416 20 30 40 50 60 ,oo 140200 100 I '( I I I I l I ~ 95 ~ ~ 90 ~~ 85 "" ~ ~ l'., 80 \ 75 ' \ r,_ \ 70 \ '~ 1--65 ~ :x: (!) 60 ~ ~ ~ >-55 '@ ID a: w 50 \\ z ii: 'z 45 \ w ~ 40 w 0. 35 30 25 20 15 10 5 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND SILT OR CLAY coarse fine coarse medium I fine Specimen Identification Classification LL PL Pl Cc Cu 0 TP-1 2.0ft. USDA: Brown Sandy Loam. uses: SM. 12] TP-3 3.0ft. USDA: Brown Loam. uses: SM. " TP-4 7.5ft. USDA: Brown Gravelly Sandy Loam. uses: SM. Specimen Identification D100 D60 D30 D10 %Silt %Clay 0 TP-1 2.0ft. 19 0.194 44.0 12] TP-3 3.0ft. 19 0.212 44.9 " TP-4 7.5ft. 37.5 0.278 36.9 EMAIL ONLY Distribution ES-2972 Conner Homes Group, LLC c/o WestPac Development 7449 West Mercer Way Mercer Island, Washington 98040 Attention: Mr. Peter O'Kane Earth Solutions NW, LLC September 24, 2013 ES-2972.02 Conner Homes Group 846 -1081h Ave Northeast, Suite 205 Bellevue, Washington 98005 Attention: Mr. Kyle Kittelman Subject: Preliminary Coal Mine Hazard Evaluation Proposed Residential Development 2724 Benson Road South Renton, Washington Reference: Earth Solutions NW, LLC Geotechnical Engineering Study ES-2972, dated September 10, 2013 Dear Mr. Kittelman: Earth Solutions NW LLC • Geotechnical Engineering • Constru(.tion Monitoring • Environmental Sciences In accordance with your request, Earth Solutions NW, LLD (ESNW) has prepared this letter providing a summary of our preliminary coalmine hazard evaluation for the subject property. Records Review The subject property is located along the east side of Benson Road South in Renton, Washington. This general area has been identified as a potential coal mine hazard area due to historic mining records. We reviewed maps K32a through K32e of the King County Coal Mine Maps inventory. Based on review, it appears that the Benson Mine was located north of the subject site about 400 feet. The majority of the mining activity appears to have been located north of South Puget Drive and to the east of Benson Road South. Summary and Opinion Based on our review of readily available coal mine maps for the area, in our opinion, the subject site is not located within a coal mine hazard area. Consistent with section 4-3-050 J1e of the Renton Municipal Code, the site should be classified as a Low Coal Mine Hazard area. LIMITATIONS The recommendations and conclusions provided in this letter are professional op1nrons consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test site locations may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this preliminary geotechnical summary if variations are encountered. 1805 -136th Place N.E., Suite 201 • Bellevue, WA 98005 • (425) 449-4704 • FAX 1425) 449-4711 Conner Homes Group September 24, 2013 ES-2792.02 Page 2 We trust this geotechnical summary meets your current needs. If you have any questions, or if additional information is required, please call. Sincerely, EARTH SOLUTIONS NW, LLC Kyle R. Campbell, P.E. Principal Earth Solutions NW, LLC APPENDIXC Conveyance Analysis StormShed 3G N--003 N--023 N-022 _-..llf---PP-O-Oi<,.,--,;:----P-Oi,,----".: .. ,~--t>-o''l P-0ie N-018 N 17 N-020 N-010 On Site Conveyance System Layout Report: Rosa I Event lrrecip (in) I ~-;;i:24 i~; ,--2.00 __ _ 1,-oy~~r I 2.90 12s year I 3 .40 1100 year I 3.90 Reach Records Record Id: P-004 !section Shape: Circular !Uniform Flow Method: Manning's !coefficient: 0.012 jRouting Method: IT·-ra-ve_l_T-im_e_S_h-ift-lContributing Hyd i_D_n_N-od_e ________ ,l~--N--0-0_3 ___ 1UpNode N-004 :Material I unspecified -IS-iz_e _____ _ 24 in Diam IEnt Losses I !Length I lup Invert I I I Min Vel I Max Vel I I 2.00 ft/s I 15.00 ft/s I lorop across MH I Record Id: P-005 !section Shape: !uniform Flow Method: I !Routing Method: I !onNode I !Material I IEnt Losses I !Length I 93.00 ft 416.64ft Groove End w/Headwall lslope Ion Invert Conduit Constraints Min Slope I Max Slope I 0.50% I 2.00% I 0.00 ft IEx/Infil Rate Circular Manning's !coefficient: Travel Time Shift !contributing Hyd N-004 lupNode unspecified lsize Groove End w/Headwall 24.00 ft ls1ope 0.69% i 416.00 ft Min Cover 3.00 ft I 0.00 in/hr I 0.012 I I N-005 I 18 in Diam I 17.96% lup Invert I 421.45 ft Ion Invert I 417.14ft - I I Conduit Constraints I I Min Vet I Max Vet I Min Slope I Max Slope I Min Cover I I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft lorop across MH i 0.00 ft IEx/Infil Rate I 0.00 in/hr Record Id: P-006 !Section Shape: I Circular I 1 · Manning'; --lc~eftici;~t;--- ------------- 0. 012 ,- !Uniform Flow Method: !Routing Method: 1 Travel Time Shift !contributing Hyd I lonNode I N-004 lupNode I N-006 I Material I unspecified lsize I 18 in Diam IEnt Losses I Groove End w/Headwall !Length I 54.00 ft lstope I 8.44% lup Invert I 426.01 ft Ion Invert I 421.45 ft I Conduit Constraints I Min Vel ,----·-Max Vel I Min Slope I Max Slope i Min Cover j2.00ft/s r 15.00 ft/s I 0.50% i 2.00% I 3.00 ft lorop across MH I 0.00 ft !Ex/Infil Rate I 0.00 in/hr Record Id: P-007 !section Shape: Circular !uniform Flow Method: Manning's !coefficient: I 0.012 !Routing Method: Travel Time Shift !contributing Hyd I lonNode N-006 lupNode I N-007 !Material unspecified lsize I 18 in Diam IEnt Losses Groove End w/Headwall !Length I 37.00 ft lstope I 5.81% lup Invert I 428.16 ft Ion Invert I 426.01 ft I Conduit Constraints I Min Vel I Max Vel I Min Slope I Max Slope I Min Cover I 1 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00ft ii lorop across MH 0.00 ft IEx/Infil Rate j 0.00 in/hr I Record Id: P-008 !Section Shape: ,--····-Circular j 'lu_n_U_o_rm_F_lo_w_M_e-th_o_d_:_I Manning's 'lc-o-ef_fi_c-ie-n-t: ___ 'l--o-.0-12 __ , ]Routing Method: 'I ---T-r-av_e_l _T-im_e_S_h-ift ___ lcontributing Hyd ,--- 'jo_n_N-od_e______ N.007 jUpNode [N-008 ···· [Material ··· ·----·_ .. _ .. _I Closed Conduits, Concrete Pipe !Size I 12 in Diam ]Ent Losses j Groove End w/Headwall , j ]Length / 33.00 ft !Slope j 5.27% Jup Invert J~---4-3_0_.4_0_ft--·--1·0-n-In_v_e-rt--·-·· 1 428.66 ft Conduit Constraints Min Vel [ · -M;~ Vel Min Slope J Max Slope Min Cover i 2.00 ft/s 'I -15-.-00_ft_/s--,---·-0.50%. -·1 ····2.00% ___ 1 3.00 ft J :=====::;:::::,=.::-cc .. 'C'C .. =====;====·=· ........ -- jDrop across MH · I 0.00 ft ]Ex/Infil Rate I 0.00 in/hr Record Id: P-009 ]section Shape: Circular [uniform Flow Method: I Manning's ]coefficient: I 0.012 !Routing Method: . !contributing Hyd I Travel Time Shift lonNode N-008 jUpNode I N-009 [Material Closed Conduits, Concrete Pipe ]Size I 12 in Diam ]Ent Losses Groove End w/Headwall ]Length 107.00 ft lslope I 5.16% Jup Invert 435.92 ft Ion Invert I 430.40 ft I Conduit Constraints I Min Vel I Max Vel I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft lorop across MH I 0.00 ft IEx/Infil Rate I o.oo in/hr Record Id: P-010 !section Shape: Circular !uniform Flow Method: I Manning's I coefficient: I 0.012 !Routing Method: I Travel Time Shift !contributing Hyd I iDnNode ______ ----,-------N-009 --------rUpNode I N-010 I Material I Closed Conduits, Concrete Pipe lsize I 12 in Diam IEnt Losses I !Length I lup In~ert ---r 11- ------------------------ I I -·--- Min Vel Max Vel I 2.00 ft/s I 15.00 ft/s 1Drop across MH I Record Id: P-011 !section Shape: jUniform Flow Method: iRouting Method: lonNode I Material IEnt Losses !Length lup Invert I I Min Vel I Max Vel I 2.00 ft/s I 15.00 ft/s lorop across MH Record Id: P-012 !section Shape: !uniform Flow Method: Groove End w/Headwall 131.00ft lslope I 3.94% 441.08 ft . ,----- jDn Invert I 435.92 ft ---------------------------------------------------------------. ------- Conduit Constraints I ·-· --· - r . ------. - r --·-------------------------- Min Slope Max Slope Min Cover I 0.50% I 2.00% I 3.00 ft 0.00 ft IEx/Infil Rate I 0.00 in/hr Circular ' Manning's I coefficient: i---0.012 I Travel Time Shift !contributing Hyd I I N-007 IUpNode I N-011 I unspecified lsize I 18 in Diam I Groove End w/Headwall I 56.00 ft ls1ope I 3.23% I 429.97 ft Ion Invert I 428.16 ft Conduit Constraints I Min Slope I Max Slope I Min Cover I 0.50% I 2.00% I 3.00 ft I 0.00 ft IEx/lnfil Rate I 0.00 in/hr Circular Manning's /coefficient: 0.012 I I rRouting Method: Travel Time Shift !contributing Hyd r-- IDnNode N-011 iupNode I N-012 !Material Closed Conduits, Concrete Pipe !size I 12 in Diam !Ent Losses Groove End w/Headwall !Length 51.00 ft [Slope r--9.24% iup Invert 435.18 ft Ion Invert I 430.47 ft 11 Conduit Constraints I 11 Min Vel I Max Vel I Min Slope I Max Slope I MinCover=1 11 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft !Drop across MH I 0.00 ft IEx/Infil Rate I 0.00 in/hr Record Id: P-013 !section Shape: Circular I ,------------,-----------',------,-------iu -~ Fl M h d M . ' le ffi . 0 012 m orm OW et o : annmgs oe 1c1ent: !Routing Method: I Travel Time Shift !contributing Hyd I IDnNode ---~--~--~ ---· -r------I I N-012 UpNode N-013 !Material I !size - Closed Conduits, Concrete Pipe I 12 in Diam !Ent Losses I Groove End w/Headwall jLength I 25.00 ft !slope I 0.52% !Up Invert I 435.31 ft ion Invert I 435.18 ft I Conduit Constraints I Min Vet I Max Vel I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft !Drop across MH I 0.00 ft fEx/lnfil Rate [ 0.00 in/hr Record Id: P-014 f section Shape: Circular funiform Flow Method: I Manning's f coefficient: I 0.012 !Routing Method: I Travel Time Shift !contributing Hyd I fDnNode I N-012 iupNode I N-014 !Material I unspecified [size I 12 in Diam [Ent Losses [Length jup Invert I I Min Ve! 12.00ft/s I I jorop across MH Max Vet 15.00 ft/s I 201.00 ft I 445.25 ft I Groove End w/Headwall [slope [on Invert ------- Condnit Constraints I Min Slope I Max Slope I I 0.50% I 2.00% I --· -· I 0.00 ft [Ex/Infil Rate --·----~---- Record Id: P-015 [section Shape: --- Circular ]Uniform Flow Method: I Manning's I coefficient: 5.01% I 435.18ft - I Min Cover 3.00 ft I 0.00 in/hr 1 0.012 !Routing Method: I Travel Time Shift !contributing Hyd ,----.--------------------1 !DnNode N-014 jUpNode I N-015 !Material I Closed Conduits, Concrete Pipe jsize j 12 in Diam jEnt Losses I Groove End w/Headwall !Length I 23.00 ft [Slope 10-:-5 2 o/; - fup1nvert r 445.37 ft jon Invert I 445.25 ft r Conduit Constraints I Min Ve! I Max Ve! I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft [Drop across MH I 0.00 ft [Ex/Infil Rate I o.oo in/hr Record Id: P-016 !section Shape: Circular juniform Flow Method: Manning's !coefficient: I 0.012 [Routing Method: Travel Time Shift [contributing Hyd I jDnNode N-014 [UpNode I N-016 !Material unspecified !size I 12 in Diam jEnt Losses Groove End w/Headwall jLength 34.00 ft lsiope I 3.00% [up Invert 446.27 ft jon Invert I 445.25 ft ----I i M~n-V-el --·--Ma~-~el I c~~:~:o~:nstrrntsMax Slope I Min c_ OV;=II_ I 2.00 ft/s 1s.oo ft/s I o~so% -r ---2.00% -I 3.oo ft =J r ---------~-------------------··--- 1Drop across MH j Record Id: P-017 [section Shape: Circular [Uniform Flow Method: I Manning's [coefficient: 10.012 [Routing Method: I Travel Time Shift [contributing Hyd I [DnNode I N-016 [UpNode I N-017 [Material I unspecified [size I 12 in Diam [Ent Losses I Groove End w/Headwall Len th g I 106.00 ft isto e p 1.50% ~[u_p_I_n-ve_r_t -------1 447.86 ft iDn Invert 446.27 ft ' Conduit Constraints I I Min Ve! Max Ve! Min Slope Max Slope Min Cover I 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft [Drop across MH 0.00 ft [Ex/Infil Rate I 0.00 in/hr Record Id: P-018 [section Shape: Circular [uniform Flow Method: I Manning's [coefficient: I 0.012 [Routing Method: I Travel Time Shift [contributing Hyd I [DnNode I N-014 [UpNode I N-018 [Material [ Closed Conduits, Concrete Pipe [size [ 12 in Diam [Ent Losses I Groove End w/Headwall [Length I 205.00 ft [Slope I 1.41% [up Invert I 448.14 ft [on Invert I 445.25 ft I Conduit Constraints I Min Vet I Max Vel I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft ]Drop across MH ___________ o_.O_O_ft=~----_ -----_~1i~_E=x-/_I=n-fi_1-l_R=-a-t=e===----,j-o-._-OO i;/h~-1 Record Id: P-019 ]section Shape: Circular juniform Flow Method: I ]coefficient: r----~----- Manning's 0.012 1--------Routing Method: I Travel Time Shift ]contributing Hyd I jDnNode I N-018 jUpNode I N-019 jMaterial j Closed Conduits, Concrete Pipe jsize j 12 in Diam I --·~ IEnt Losses Groove End w/Headwall 1----------- Length I 33.00 ft !Slope I 3.39% jup Invert I 449.26 ft Jon Invert I 448.14 ft -------..... - Conduit Constraints I Min Vel I Max Vel I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% 1----3.00 ft--- jDrop across MH I 0.00 ft ]Ex/lnfil Rate JQ.00 in/hr Record Id: P-020 Jsection Shape: Circular Juniform Flow Method: I Manning's ]coefficient: I 0.012 jRouting Method: I Travel Time Shift ]contributing Hyd I jDnNode I N-009 jUpNode I N-020 ]Material I unspecified ]size I 6 in Diam jEnt Losses I Groove End w/Headwall ]Length I 20.00 ft jslope I 9.10% jup Invert I 438.24 ft jon Invert I 436.42 ft I Conduit Constraints I Min Vel I Max Vel I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft ]Drop across MH I 0.00 ft ]Ex/Infil Rate I 0.00 in/hr Record Id: P-021 !section Shape: !uniform Flow Method: jRouting Method: ----------- jDnNode !Material jEnt Losses jLength jup Invert I ,I Min Vet I Max Vet ii 2.00 ft/s I 15.00 ft/s ' jorop across MH - Record Id: P-022 jsection Shape: juniform Flow Method: jRouting Method: jonNode jMaterial [Ent L;s~es jLength jup Invert I I Min Vet I Max Vel I 2.00 ft/s I 15.00 ft/s jorop across MH Record Id: P-023 jsection Shape: juniform Flow Method: jRouting Method: I I I i I I I I I I I I I I Circular Manning's !Coefficient: I 0.012 Travel Time Shift jcontributing Hyd I jUpNode ---·-- I N-011 N-021 unspecified jsize 16-;~-Diam Groove End w/Headwall 22.00 ft jstope I 11.64% 433.53 ft Jon Invert I 430.97 ft Conduit Constraints i Min Slope I Max Slope i Min Cover 0.50% I 2.00% I 3.00 ft 0.00 ft jEx/Infil Rate j 0.00 in/hr -------·--- Circular Manning's !coefficient: ·· 1--0.012 Travel Time Shift jcontributing Hyd I N-011 jUpNode I N-022 unspecified [si~----I 6 in Diam Groove End w/Headwall 43.00 ft jstope I 5.60% 433.38 ft Jon Invert I 430.97 ft Conduit Constraints Min Slope I Max Slope I Min Cover 0.50% I 2.00% I 3.00 ft 0.00 ft /Exllnfil Rate I 0.00 in/hr Circular I , ______________ , Manning's /coefficient: --------------! Travel Time Shift jcontributing Hyd 0.012 lonNode I Material IEnt Losses ~-----·--.. -· ngth lup Invert I I I Min Ve! I Max Vet I 2.00 ft/s I 15.00 ft/s jorop across MH Record Id: P-024 jsection Shape: !uniform Flow Method: jRouting Method: jonNode jMaterial [EntL~;s-;;---· --------- jLength I N-015 lupNode I N-023 I unspecified jsize I 6 in Diam I Groove End w/Headwall I 17.00 ft jstope I 2.18% ,---446.24 ft jon Invert I 445.87 ft Conduit Constraints i ---1--------~I Miu Slope Max Slope Min Cover I 0.50% I 2.00% I 3.00 ft I 0.00 ft jEx/Infil Rate I 0.00 in/hr Circular r··--------Manning's jcoefficient: I 0.012 I Travel Time Shift jcontributing Hyd I I jUpNode I ... N-019 N-024 I unspecified jsize I 8 in Diam I Groove End w/Headwall I 13.00 ft jstope I 1.62% [Up Invert 449 97 ft jon Invert j 449 76 ft 1 11 Conduit Constraints I Min Vet I Max Ve! I Min Slope I Max Slope I Min Cover I 2.00 ft/s I 15.00 ft/s I 0.50% I 2.00% I 3.00 ft jorop across MH I 0.00 ft jEx/Infil Rate I 0.00 in/hr Node Records Record Id: N-003 jDescrip: I jrncrernent jo.10 ft jstart El. j4 I 6.50 ft jMax El. j42 l.50 ft jv oid Ratio j 100.00 j I f jcondition jProposed jStructure Type jCB-TYPE 2-48 jEnt Ke jGroove End w/Headwall (ke=0.20) jChannelization jNo Special Shape !catch lo.oo ft !Bottom Area 112.5664 sf IMH/CB Type Node Record Id: N-004 loescrip: !Increment lo. IO ft I ~-ta-rt-El-. l417:64_ft____ ---~,M_a_x-El-. --cj4-2-8.-14_ft ___ l j~V-o-id_R_a-ti-o 'jl-00 ___ 00______________ 1 ~---~---------,----~----1 jcondition jProposed ]Structure Type lcB-TYPE 2-48 jEnt Ke jGroove End w/Headwall (ke=0.20) jchannelization jNo Special Shape 1Ca-i~h ___ l0:00_ft ______ jBottom Area j12.5664 sf IMH/CB Type Node __________________ _ Record Id: N-005 jDescrip: !Increment j0.10 ft I ~IS-ta_rt_E_l._~j42-l-.9-5_ft ________ jMax El. j428.45 ft I ----------------~----- jvoid Ratio jl00.00 I jcondition jProposed !Structure Type !CB-TYPE 2-48 jEnt Ke jGroove End w/Headwall (k~0.20) jchannelization jNo Special Shape !Catch [0.00 ft-jBottom Area j 12.5664 sf IMH/CB Type Node Record Id: N-006 joescrip: I !Increment 10.10 ft jStart El. j426.51 ft jMax EL j43 l.5 l ft [Void Ratio I 100.00 I I i I condition jProposed jstructure Type [CB-TYPE 2-48 jEnt Ke !Groove End w/Headwall (ke=0.20) !channelization [No Special Shape !catch 10.00 ft jBottom Area jl2.5664 sf jMH/CB Type Node Record Id: N-007 loescrip: I !Increment 10.10 ft ~IS-ta_rt_E_l._~l42-8-.6-6_ft ________ :Max El. 1433.66 ft Iv oid Ratio I 100.00 ~--1 r !condition !Proposed I structure Type l~C-B--T_Y_P_E 2-48 ]Ent Ke !Groove End w/Headwall (ke=0.20) I channelization INo Special Shape !Catch lo.oo ft !Bottom Area I 12.5664 sf IMH/CB Type Node Record Id: N-008 loescrip: --~~~;~;~;-. · 10.ioft !start El. 1430.40 ft iMax El. 1435.40 ft lvoid Ratio ~ll-00-.0-0 ________ _ r ~-----rcondition [Proposed . l~St_ru_c-tu-re_T_yp_e !CB-TYPE 2-48 IEnt Ke !Groove End w/Headwall (ke=0.20) !Channelization INo Special Shape !catch lo.oo ft !Bottom Area 112.5664 sf !MH/CB Type Node Record Id: N-009 loescrip: I [Increment 10.10 ft !start El. 1435.92 ft IMax El. 1440.92 ft lvoid Ratio 1100.00 I I r !condition !Proposed [structure Type lcB-TYPE I IEnt Ke !Groove End w/Headwall (ke=0.20) !channelization INo Special Shape [catch [o.oo ft !Bottom Area [3.97 sf IMH/CB Type Node Record Id: N-010 loescrip: [Increment lo. IO ft !start El. ~l44-l-.0-8_ft ________ l~M-a_x_E_l. ___ l~4-46-.-08_ft ___ , IVoid Ratio 1100.00 r !condition [Proposed !structure Type lcB-TYPE 1 [Ent Ke [Groove End w/Headwall (ke=0.20) [Channelization [No Special Shape [Catch [0.00 ft [Bottom Area [3.97 sf [MH/CB Type Node Record Id: N-011 ri:i~;;ip: -r----------------~ncrement [o.Jo_ft __ _ [Start El. ,_[43_0_.4_7_ft _______ [~M-ax_E_l_. --,-[4-35_.4_7_ft __ [Void Ratio [ 100.00 r ------[condition ,-[P_ro_p_o-se_d ________ [Structure Type [CB-TYPE 2-48 [Ent Ke [Groove End w/Headwall (ke=0.20) [channelization [No Special Shape [catch j0.00 ft ]Bottom Area j 12.5664 sf jMH/CB Type Node Record Id: N-012 1Descrip: ]Increment [o. IO ft I j~St-art-El-. -r-[4-35-.-18_ft ________ 'JM-ax_E_l. __ j440.18 ft j rv-;;;-,TR.rti~~-0-0.00___ r ------,--------r r[C-o-nd-i-ti-on-'jp_r_o_po_s_e_d _________ ,j_St_ru_c-tu_r_e _T_yp_e [CB-TYPE 2-48 ]Ent Ke ]Groove End w/Headwall (ke=0.20) ]Channelization ]No Special Shape [Catch [0.00 ft [Bottom Area [ 12.5664 sf [MH/CB Type Node Record Id: N-013 Joescrip: ]Increment jo.10 ft ,-[S-ta_rt_E_L_j,-43_5_.3_l_ft ________ lMax El. ]440.18 ft jVoidRatio]!00.00 -----r-----·r ]Condition [Proposed j,-S-tru_c_t-ur_e_T_yp_e_ r[C_B ___ T_Y_P_E_l __ [Ent Ke [Groove End w/Headwall (ke=0.20) ]channelization ]No Special Shape [Catch [0.00 ft ]Bottom Area [3.97 sf [MH/CB Type Node Record Id: N-014 loescrip: !Increment lo. IO ft !start El. ~144-5-.2-S_ft ________ l~M-a-x -El-. --,l-45-0-.0-6-ft---i lvoid Ratio l~H-l0-.0-0---------~----,------·j !condition !Proposed !structure Type !CB-TYPE 2-48 !Ent Ke ra;:;~~E~dw/Headwali°(k~20)1Cha~~ti~~[No Special Shap~ I !catch lo.OO ft !Bottom Area 112.5664 sf IMH/CB Type Node I Record Id: N-015 [oescrip: I !Increment 10.10 ft !Start El. 1445.37 ft !Max El. 1450.06 ft rv---i--oid Ratio I 00.00 T---I r I condition !Proposed !structure Type lcB-TYPE I !Ent Ke !Groove End w/Headwall (ke=0.20) !channelization !No Special Shape !catch 10.00 ft ,- jBottom Area 13.97 sf IMH/CB Typ~Node · Record Id: N-016 loescrip: I !increment rom ____ _ !start El. 1446.27 ft IMax El. 1451.27 ft !Void Ratio I 100.00 I I r !condition !Proposed !structure Type lcB-TYPE I !Ent Ke !Groove End w/Headwall (ke=0.20) !channelization !No Special Shape !catch lo.oo ft !Bottom Area 13.97 sf IMH/CB Type Node Record Id: N-017 loescrip: !Increment lo. IO ft !start El. ~l44-7-.8-6_ft ________ l~M-a-x -El-. --,l-45-2-.8-6-ft---i Iv oid Ratio I 100.00 r ----- !condition !Proposed !structure Type lcB-TYPE 1 IEnt Ke loroove End w/Headwall (ke=0.20) !channelization INo Special Shape lcatch lo.OO ft !Bottom Area 13 .97 sf IMH/CB Type Node ---------·---·-·------------·----- Record Id: N-018 loescrip: lrncrement lo.10 ft jstart El. j448.14--ft --· ---jMax El. 1455.07 ft IVoid Ratio ~110-0-.0-0________ r !condition !Proposed j~St_ru_c-tu-re_T_yp_e·/rc-B--T-Y_P_E_l -- IEnt Ke loroove End w/Headwall (ke=0.20) !Channelization INo Special Shape rc~t~h --10:oo_ft____ -----······· ·· ·· rB~ii~~ :,;,.~~;; ~.-97 ;f----- IMH/CB Type Node Record Id: N-019 loescrip: !Increment lo. l O ft !start El. /449.26 ft ------,,------------~-----------· 1Max El. 1454.26 ft !Void Ratio [100.00 r l~C-on-d-it-io-n-rlP_ro_p_o-se_d ________ rls-tr-uc-t-ur_e_T_yp_e_'l~c-B--T-Y_P_E_l -- IEnt Ke loroove End w/Headwall (ke=0.20) /channelization INo Special Shape lcatch lo.OO ft !Bottom Area 13.97 sf IMH/CB Type Node Record Id: N-020 loescrip: I lrncrement lo. IO ft !start El. /438.24 ft !Max El. 1443.24 ft [voidRatio/100.00 j j I I condition IEnt Ke /catch !Proposed ~IS-tru-c-tur_e _T_yp_e_'I_C_B--T-Y_P_E_l __ !Groove End w/Headwall (ke=0.20) !channelization INo Special Shape lo.OO ft !Bottom Area 13.97 sf ~IM_H_/_C_B_T_y-pe-N-od_e ________ . ----·--·-·--·---·-· J Record Id: N-021 loescrip: I Increment 10.10 ft !Start El. 1433.53 ft IMax El. [438.53 ft [v~IaiatT~l100-.oo--I !condition l~P_ro_p-os_e_d ________ 'l~st_ru_c-tu_r_e _T_yp_e_"lc_B ___ T_Y_P_E_l __ IEnt Ke !Groove End w/Headwall (ke=0.20) !channelization INo Special Shape lcatch lo.oo ft !Bottom Area -13.97 sf IMH/CB Type Node Record Id: N-022 [Descrip: ;Increment lo.10 ft !start El. 1433.38 ft IMax El. ·--[437.38_ft __ - Iv oid Ratio I 100.00 I r !condition !Proposed !structure Type [CB-TYPE I IEnt Ke !Groove End w/Headwall (ke=0.20) [chan~elization [No Specia-1--S-ha_p_e lcatch lo.oo ft !Bottom Area 13.97 sf [MH/CBTypeNode ------- Record Id: N-023 loescrip: !Increment [0.10 ft !start EL[ ~44_6_.2_4_ft ________ l~M_a_x_E_l. __ .~[4-50-.-74_ft ___ , [Void Ratio 1100.00 I !condition [Proposed !structure Type [CB-TYPE 1 IEnt Ke [Groove End w/Headwall (ke=0.20) !Channelization [No Special Shape [Catch lo.oo ft !Bottom Area 13.97 sf IMH/CB Type Node Record Id: N-024 loescrip: I !Increment lo. IO ft l~St_art_E_l. _rl4-4-9.-97_ft _______ lMax El. 1453.47 ft l~V-oi_d_R-at1-·0·~11-00-.0-0--------rl----l r !condition !Proposed !structure Type ~lc_B_-T_Y_P_E--1-- IEnt Ke !Groove End w/Headwall (ke=0.20) !channelization !No Special Shape !catch lo.oo ft !Bottom Area 13.97 sf IMH/CB Type Node Contributing Drainage Areas Record Id: B-005 Design Method F' I IDF Table: ------------. ----.... --------- I I R,tio,,1 Design Method IDF Table: i I Design Method I R,tioMI IDF Table: .. "" .. - Design Method I .,,,,,,, IDF Table: Design Method I Ra<Joru,J IDF Table: Design Method I R,tiooal IDF Table: Design Method I R,tiooal IDF Table: Design Method I R,tiooal IDF Table: SeattleRecord Id: B-006 . .. SeattleRecord Id: 8-007 SeattleRecord Id: B-008 -----. -· .. --·-·"'·-·-------·--· -----... SeattleRecord Id: B-009 SeattleRecord Id: B-010 SeattleRecord Id: B-011 SeattleRecord Id: B-012 SeattleRecord Id: B-013 - J SeattleRecord Id: B-014 Design Method Rational IDF Table: -------....... J i I Ratioofil r SeattleRecord Id: B-015 ' i I Design Method IDF Table: Design Method I lu<ioMI I IDF T•ble, SeattleRecord Id: B-016 -I R,;,~~1 I SeattleRecord Id: B-017 Design Method IDF Table: ·--- I r,:o,,1 I ----- SeattleRecord Id: B-018 Design Method IDF Table: I ' I --.. . .. ------------------,. ------____ J Design Method 1 .. ,,00,l IDF Table: Se•ttl•Reronl Id, 8--019~ -- I Ra<ioo•I SeattleRecord Id: B-020 Design Method IDF Table: --------·-·-·-··· I I R.,ioo,I SeattleRecord Id: B-021 I Design Method IDF Table: I '"'""'"' SeattleRecord Id: B-022 Design Method IDF Table: I R,<iom,J SeattleRecord Id: B-023 Design Method IDF Table: I Rotiooal SeattleRecord Id: B-024 Design Method IDF Table: ROUTEHYD [] THRU [Rosa] USING (100 yr] AND [Seattle] NOTZERO RELATIVE RATIONAL Rational Method analysis Reach ID Area (ac) TC (min) i (in/hr) Flow (cfs) Full Q Full ratio nDepth Size nVel (ft/s) fVel (ft/s) CArea (cfs) (ft) P-024 0.37 6.3 3.209 0.8809 1.6703 0.5274 0.3441 8 in Diam 4.8474 4.7859 B-024 12in P-019 0.51 6.3447 3.1966 1.1971 7.1297 0.1679 0.2768 Diam 6.7592 9.0778 B-019 12in P-018 1.38 6.4261 3.1745 2.746 4.5952 0.5976 0.5571 Diam 6.1067 5.8507 B-018 P-023 0.36 6.3 3.209 0.852 0.8999 0.9467 0.3877 6 in Diam 5.2156 4.5832 B-023 12in P-015 1.51 6.3543 3.194 2.9289 2.7908 1.0495 0.8732 Diam 4.0256 3.5533 B-015 12in P-017 0.51 6.3 3.209 1.0766 4.7399 0.2271 0.3239 Diam 4.8867 6.035 B-017 12in P-016 0.87 6.6615 3.1129 1.7899 6.7032 0.267 0.3528 Diam 7.2278 8.5348 B-016 12in P-014 3.89 6.9856 3.0333 7.2678 8.6624 0.839 0.7016 Diam 12.3463 11.0294 B-014 12in P-013 0.13 6.3 3.209 0.292 2.7908 0.1046 0.2179 Diam 2.3114 3.5533 B-013 12in P-012 4.15 7.2569 2.971 7.6592 11.7611 0.6512 0.5879 Diam 15.951 14.9747 B-012 P-022 0.52 6.3 3.209 1.2306 1.4423 0.8532 0.3557 6 in Diam 8.2382 7.3458 B-022 P-021 0.51 6.3 3.209 1.2018 2.0795 0.5779 0.2728 6 in Diam 10.9709 10.5906 B-021 18in P-011 5.21 7.3102 2.9592 9.9324 20.5135 0.4842 0.7362 Diam 11.5114 11.6083 B-011 12in P-010 0.68 6.3 3.209 0.921 7.6808 0.1199 0.2342 Diam 6.5776 9.7796 B-010 P-020 0.19 6.3 3.209 0.4444 1.8386 0.2417 0.1672 6 in Diam 7.7249 9.3641 B-020 12in P-009 0.98 6.6319 3.1204 1.5758 8.7902 0.1793 0.2865 Diam 8.4777 11.1921 B-009 12in P-008 1.08 6.8423 3.0678 1.7655 8.8867 0.1987 0.3023 Diam 8.815 11.3148 B-008 18in P-007 6.33 7.3913 2.9414 11.6524 27.5053 0.4236 0.6817 Diam 14.914 15.5648 B-007 18in P-006 6.41 7.4326 2.9325 11.7901 33.1576 0.3556 0.6176 Diam 17.1849 18.7633 B-006 18 in P-005 0.11 6.3 3.209 0.2343 48.3538 0.0048 0.0752 Diam 7.0615 27.3627 B-005 24in P-004 6.52 7.485 2.9213 11.9583 20.3857 0.5866 1.1013 Diam 6.7447 6.489 HGL Analysis From To Node HG El (ft) App (ft) Bend (ft) Junct Loss Adjusted Max El (ft) Node (ft) HG El (ft) 426.3 No approach losses at node N-006 because inverts and/or crowns are offset. N-004 N-003 426.7901 0.6912 0.6581 0.0115 426.7686 428.14 N-006 N-004 428.5084 ------0.0699 ------428.5784 431.51 N-007 N-006 430.6006 ------0.683 0.0675 431.3511 433.66 No approach losses at node N-012 because inverts and/or crowns are offset. N-011 N-007 432.364 1.4767 0.6114 0.3398 431.8385 435.47 N-012 N-011 438.7616 ------0.115 0.0443 438.9209 440.18 N-014 N-012 448.5255 ------0.3272 0.1551 449.0078 450.06 N-018 N-014 450.2673 0.0361 0.0144 ------450.2457 455.07 No approach losses at node N-024 because inverts and/or crowns are offset. N-019 N-018 450.3205 0.3649 0.3143 ------450.2699 454.26 N-024 N-019 450.6559 ------------------450.6559 453.47 No approach losses at node N-023 because inverts and/or crowns are offset. N-015 N-014 449.3991 0.2924 0.0061 ------449.1128 450.06 N-023 N-015 449.7951 ------------------449.7951 450.74 N-016 N-014 449.1773 0.0292 0.002 ------449.1501 451.27 N-017 N-016 449.2672 ------------------449.2672 452.86 N-013 N-012 438.9249 ------------------438.9249 440.18 N-022 N-011 434.9167 ------------------434.9167 437.38 N-021 N-011 435.0346 ------------------435.0346 438.53 N-008 N-007 431.514 0.0625 0.0119 ------431.4634 435.4 N-009 N-008 436.6714 ------0.0053 0.2185 436.8951 440.92 N-010 N-009 441.624 ------------------441.624 446.08 N-020 N-009 438.7489 ------------------438.7489 443.24 N-005 N-004 426.769 ------------------426.769 428.45 Conduit Notes Reach HWDepth HW/D Q (cfs) TWDepth De (ft) Dn (ft) Comment (ft) ratio (ft) P-004 10.7901 5.3951 11.96 10.3 1.2426 1.1013 Outlet Control P-006 2.4984 1.6656 11.79 5.3186 1.3058 0.6176 SuperCrit flow, Inlet end controls P-007 2.4406 1.6271 11.65 2.5684 1.2998 0.6817 SuperCrit flow, Inlet end controls P-011 4.204 2.8027 9.93 3.1911 1.2154 0.7362 Outlet Control P-012 3.5816 3.5816 7.66 1.3685 0.9818 0.5879 SuperCrit flow, Inlet end controls P-014 3.2755 3.2755 7.27 3.7409 0.9781 0.7016 SuperCrit flow, Inlet end controls P-018 5.0174 5.0174 2.75 3.7578 0.7106 0.5571 Outlet Control P-019 2.1805 2.1805 1.2 2.1057 0.4613 0.2768 Outlet Control P-024 0.6859 1.029 0.88 0.5099 0.445 0.3441 SuperCrit flow, Inlet end controls P-015 4.1487 4.1487 2.93 3.7578 0.7342 0.8732 Outlet Control P-023 3.9257 7.8515 0.85 3.2428 0.4535 0.3877 Outlet Control P-016 3.9273 3.9273 1.79 3.7578 0.5697 0.3528 Outlet Control P-017 2.9972 2.9972 1.08 2.8801 0.4364 0.3239 Outlet Control P-013 3.7449 3.7449 0.29 3.7409 0.2225 0.2179 Outlet Control P-022 1.5367 3.0733 1.23 0.8685 0.487 0.3557 SuperCrit flow, Inlet end controls P-021 1.5046 3.0092 1.2 0.8685 0.4859 0.2728 SuperCrit flow, Inlet end controls P-008 2.854 2.854 1.77 2.6911 0.5656 0.3023 Outlet Control P-009 0.7514 0.7514 1.58 1.0634 0.5329 0.2865 SuperCrit flow, Inlet end controls P-010 0.544 0.544 0.92 0.9751 0.4025 0.2342 SuperCrit flow, Inlet end controls P-020 0.5089 1.0179 0.44 0.4751 0.3398 0.1672 SuperCrit flow, Inlet end controls P-005 9.629 6.4193 0.23 9.6286 0.178 0.0752 Outlet Control ft !47'. C,:lj • 4 5784 tt 449 7951 tt 438 9249 tt 44gij 28 ft 434.9167 ft i ; \"' 11 , .;pai a,-'.-•"'-ft-,,~,..,,,.~,~1;;--"...,;~---,,f,~ .. .-;,~;;----~"~'~':"rn '~ o,, ' 0346 ft 438 148'9 ft N-OUTLET • .",'\ \ \ \ N--002B P--002B Pond Outlet I Layout Report: Outlet I Event IPrecip (in) 12 yr 24 hr I 2.00 i1oyear I 2.90 l2s year I 3 .40 1100 year I 3.90 Reach Records Record Id: P-001 ]Section Shape: Circular j ~--------~-----------~-------~----, !Uniform Flow Method: Manning's !coefficient: 0.012 I -iR_o_u_ti-ng_M_e-th_o_d_: ___ , ___ T_ra_v-el_T_i_m_e_S_h_ift ___ lcontributing Hyd fDnNode N-OUTLET iupNode f N-001 I Material ~C-Jo-s-ed_C_o_n_d_u_it-s,-C-o-n-cr_e_te-P-ip_e_jSize j 18 in Dian1 I_E_n_t_L_o-ss-es_____ Groove End w/Headwall !Length 43.00 ft ls1ope I 2.00% iup Invert 413.72 ft j_D_n_I_n-ve_r_t ___ T 412.86 ft 8 ====-c·:_:_::·======c=o=n=d=UI=.t=C=o=n=st=r=ai=n=ts============;I Min Vel Max Vel Min Slope Max Slope Min Cover I .00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft lorop across MH 0.00 ft IEx/Infil Rate I 0.00 in/hr Record Id: P-002A !section Shape: Circular I !uniform Flow Method: Manning's I coefficient: I 0.012 I !Routing Method: Travel Time Shift !contributing Hyd I lonNode N-001 iupNode I N-002A !Material Closed Conduits, Concrete Pipe lsize I is in Diam IEnt Losses Groove End w/Headwall !Length 31.00 ft ls1ope 5.97% !up Invert 415.57 ft Ion Invert I 413.n ft [ Conduit Constraints I Min Vet -"·--·-· Max Vet Min Slope Max Slope Min Cover I 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft !Drop across MH 0.00 ft IEx/Infil Rate I 0.00 in/hr Record Id: P-0028 !section Shape: Circular r---------------------r --------------------1 Uniform Flow Method: Manning's Coefficient: I 0.012 !Routing Method: I Travel Time Shift !contributing Hyd I !OnNode I N-STORMGA TE lupNode I N-002B iMaterial I Closed Conduits, Concrete Pipe lsize I 1s in Diam 11-~------~--~---, Ent Losses Groove End w/Headwall !Length I 42.00 ft fsiope I 0.50% lup Invert I 420.41 ft Ion Invert I 420.20 ft I Conduit Constraints I Min Vet I Max Vel I Min Slope I Max Slope I MioCm,=11 1--------i-------- I I 2.00 ft/s 15.00 ft/s I 0.50% 2.00% 3.00 ft ~[o_r_o_p_a_c_ro_s_s _M_H ___ ~ _____ o._o_o_ft ____ ~IE_x_l_In_fi_d_R_a_te __ ---'-1 _o_.oo in/hr I Record Id: P-STORMGATE !section Shape: Circular !uniform Flow Method: I Manning's !coefficient: I 0.012 !Routing Method: I Travel Time Shift !contributing Hyd I lonNode I N-002A [UpNode IN-STORMGATE !Material !closed Conduits, Concrete Pipe [size I 18 in Diam !Ent Losses I Groove End w/Headwall !Length I 11.00 ft !slope I 42.09% lup Invert I 420.20 ft Ion Invert I 415.57 ft I Conduit Constraints I Min Vet I Max Vet I Min Slope I Max Slope I Min Cover 11 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft !Drop across MH 0.00 ft IEx/Infil Rate 0.00 in/hr Node Records Record Id: N-001 !Increment ' 10.10 ft loescrip: rs1~rtE1.--f41-3.-72ft ___ _ ------ 0:M-ax_E_I_. --1417.28 ft !Void Ratio 1~10-0-.0-0---------,----- !condition !Existing !Structure Type lcB-TYPE 2-48 IEnt Ke ]Groove End w/Headwall (ke=0.20) ]Channelization INo Special Shape ]Catch j0.00 ft ]Bottom Area ]12.5664 sf IMH/CB Type Node ---------------------------------- Record Id: N-002A joescrip: ]Increment Jo. IO ft --------- 1st a rt El. ]415.57 ft ]Max EL [420.57 ft -iV-oi_d _R_atJ-.o-j~I-00-.0-0 ________ [ ---------,--------r ]Condition ]Existing !structure Type lcB-TYPE 2-48 IEnt Ke !Groove End w/Headwall (ke=0.20) ]Channelization ]No Special Shape lcatch j0.00 ft !Bottom Area 112.5664 sf IMH/CB Type Node Record Id: N-002B jDescrip: I !Increment j0.10 ft ]Start EL ]420.41 ft ]Max EL ]427.20 ft ]Void Ratio I 100.00 I I r ]condition ]Existing ]Structure Type lcB-TYPE 2-48 ]Ent Ke ]Groove End w/Headwall (ke=0.20) ]Channelization jNo Special Shape ]Catch jo.oo ft ]Bottom Area 112.5664 sf jMH/CB Type Node Record Id: N-OUTLET i;:;-::----. 1--~--------------~ 1ucscnp: I Increment lo. IO ft !start El. 1412.86 ft _M_a_x_E_l. ___ ~l4-14-.-66_ft ___ , Iv oid Ratio I 100.00 I !condition !Existing !structure Type !Dummy IEnt Ke !Groove End w/Headwall (ke=0.20) !channelization ~IN_o_S_p-ec-ia_l_S_h-ap-e !Catch lo.OO ft !Bottom Area I0.00 sf IMH/CB Type Node Record Id: N-STORMGATE !Descrip: I I Increment 10.10ft !Start El. /420.20 ft IMax El. /425.00 ft Iv oid Ratio/ 100.00 I I r I condition /Existing jStructure Type /CB-TYPE 2-48 /Ent Ke !Groove End w/Headwall (ke=0.20) !Channelization INo Special Shape lcatch 10.00 ft !Bottom Area 112.5664 sf IMH/CB Type Node Licensed to: Engenious Systems, Inc. Appended on: Tuesday, April 15, 2014 9:18:24 AM ROUTEHYD [] THRU [Outlet] USING (100 year] AND[] NOTZERO RELATIVE Fixed Flow Gravity Analysis using fixed flowrates Reach ID Flow (cfs) Full Q Full ratio nDepth Size nVel (ft/s) fVel (ft/s) CFlow (cfs) (ft) 18in P-002B 7.9 8.0683 0.9791 1.2028 Diam 5.2013 4.5657 7.9 18in P-STORMGATE 7.9 74.0274 0.1067 0.3298 Diam 27.4272 41.8909 0 18in P-002A 7.9 27.8742 0.2834 0.5465 Diam 13.5728 15.7735 0 18in P-001 7.9 16.1366 0.4896 0.7409 Diam 9.081 9.1315 0 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss Adjusted Max El (ft) (ft) HG El (ft} 414.36 N-001 N-OUTLET 415.4488 ------0.0309 ------415.4798 417.28 N-002A N-001 417.3048 ------0.0495 ------417.3543 420.57 N-STORMGATE N-002A 421.989 ------0.0113 ------422.0002 425 N-002B N-STORMGATE 422.5739 ------------------422.5739 427.2 Conduit Notes Reach HW Depth (ft) HW/D Q (cfs) ratio TWDepth De (ft) Dn (ft) Comment (ft) P-001 1.7288 1.1525 7.9 1.5 1.0897 0.7409 SuperCrit flow, Inlet end controls P-002A 1.7348 1.1565 7.9 1.7598 1.0897 0.5465 SuperCrit flow, Inlet end controls P-STORMGATE 1.789 1.1926 7.9 1.7843 1.0897 0.3298 SuperCrit flow, Inlet end controls P-0028 2.3739 1.5826 7.9 1.8002 1.0897 1.2028 Outlet Control 414 36 ft • 422 0002 ft 422 5739 ft 7-90 c1s---1•a-----------• 7 90 els APPENDIX D Operations and Maintenance Manual KING COUNTY, WASHIKGTON, SURFACE WATER DESIGN MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 1 -DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed General Trash & Debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Poisonous Vegetation Any poisonous or nuisance vegetation which may No danger of poisonous vegetation or Noxious Weeds constitute a hazard to County personnel or the where County personnel or the public. public might normally be. Coordination with Seattle-King County Health Department Contaminants and Oil. gasoline, or other contaminants of one gallon No contaminants present other than Pollution or more, or any amount found thal could: a surface film. (Coordination with 1) cause damage to plant, animal, or marine life; Seattle/King County Health 2) constitute a fire hazard; or 3) be flushed Department) downstream during rain storms. Unmowed If facility is located in private residential area, When mowing is needed, Grass/Ground Cover mowing is needed when grass exceeds 18 grass/ground cover should be inches in height. In other areas, the general mowed to 2 inches in height. policy is to make the pond site match adjacent Mowing of selected higher use areas ground cover and terrain as long as there is no rather than the entire slope may be interference with the function of the facility. acceptable for some situations. Rodent Holes Any evidence of rodent holes if facility is acting Rodents destroyed and dam or berm as a dam or berm, or any evidence of water repaired. (Coordination with piping through dam or berm via rodent holes or Seattle/King County Health other causes. Department) Insects When insects such as wasps and hornets Insects destroyed or removed from interfere with maintenance activities. Mosquito site. Mosquito control: Swallow complaints accompanied by presence of high nesting boxes or approved larvicide mosquito larvae concentrations (aquatic phase). applied. Tree Growth Tree growth threatens integrity of berms acting Trees do not hinder maintenance as dams, does not allow maintenance access, or activities. Harvested trees should interferes with maintenance activity (Le., slope be recycled into mulch or other mowing, silt removal, vactoring, or equipmenl beneficial uses (e.g., alders for movements). If trees are a threat to berm firewood). integrity or not interfering with access, leave trees alone. 2005 Surface Water Design Manual -Appendix A 1/24/2005 A-I APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 1 -DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Side Slopes of Pond Erosion Eroded damage over 2 inches deep where cause Slopes should be stabilized by using of damage is still present or where there is appropriate erosion control potential for continued erosion. measure(s): e.g., rock Any erosion observed on a compacted berm reinforcement, planting of grass, embankment. compaction. If erosion is occurring on compacted berms a licensed civil engineer should be consulted to resolve source of erosion. Storage Area Sediment Accumulated sediment that exceeds 10% of the Sediment cleaned out to designed designed pond depth. pond shape and depth; pond reseeded if necessary to control erosion. Liner Damage Liner is visible and has more than three %-inch Liner repaired or replaced. (If Applicable) holes in it. Pond Bem,s (Dikes) Setllement Any part of berm that has settled 4 inches lower Dike should be built back to the than the design elevation. Settling can be an design elevation. indication of more severe problems with the berm or outlet works. A licensed civil engineer should be consulted to determine the source of the settlement. Emergency Tree Growth Tree growth on emergency spillways create Trees should be removed. If root Overflow/Spillway blockage problems and may cause failure of the system is small (base less than 4 and Berms over 4 benn due to uncontrolled overtopping. inches) the root system may be left feet in height. Tree growth on berms over 4 feet in height may in place. Otherwise the roots should be removed and the berm restored. lead to piping through the berm which could lead A licensed civil engineer should be to failure of the berm. consulted for proper berm/spillway restoration. Emergency Rock Missing Only one layer of rock exists above native soil in Replace rocks to design standards. Overflow/Spillway area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. 1/24/2005 2005 Surface Water Design Manual -Appendix A A-2 APl'EKDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL. CONVEYANCE. AND WQ f ACII.ITJES NO. 4 -CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component 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 working properly 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 1124/2005 A-5 APPENDIX J\ MAINTFNAI\CF. RFQUIRFMFNTS 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 Y., 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 1 /3 the No trash or debris in the catch depth from the bottom of basin to invert the basin. lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outlet pipes free of trash or more than 1/3 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 % 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 Top slab is free of holes and cracks. or cracks wider than X inch (intent is to make 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 % inch of the frame from the top slab. Cracks in Basin Cracks wider than 1h 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 1h inch and longer than 1 foot No cracks more than 1/4 inch wide at at the joint of any inleUoutlet pipe or any the joint of inleUoutlet pipe. evidence of soil particles entering catch basin through cracks. SettlemenU 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 inleUoutlet pipe joints that No vegetation or root groi.,111:h is more than 6 inches tall and less than 6 inches present. apart. Pollution Nonflammable chemicals of more than 1h cubic No pollution present other than foot per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only 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 % 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 maintenance person. sealing off access to maintenance. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, Ladder meets design standards and misalignment, rust, cracks, or sharp edges. allows maintenance person safe access. 1/24/2005 2005 Surface Water Design Manual -Appendix A A-6 APl'L:NlllX A MAIN IENANCL REQUIREMENTS FOR FLOW CONTROi.. C:ONVEYANC:F. AND WQ FACILITIES NO. 5 -CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed Meta! Grates Unsafe Grate Grate with opening wider than 7/e inch. 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. 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 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 o/. 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 or 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 it 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 1/.i 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 % 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 1/24/2005 A-7 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL CONVEYANCE. AND WQ 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 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 See "Detention Ponds" Table No. 1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design standards. Place or Missing (If the rock lining. Applicable). N0.11-GROUNDS (LANDSCAPING) Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component 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 V..1 ater Design Manual -Appendix A 1/24/2005 A-9 APPENDIX i\ Mi\lNTENA'ICE REQlllREME'ITS FLOW CONTROL CONVEY i\NCE. AND WQ FACILITIES NO. 12 -ACCESS ROADS Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintena nee is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which could square feet (i.e., trash and debris would fill up damage tires. one standards size garbage can). Blocked Roadway Debris which could damage vehicle tires (glass Roadway free of debris which could or metal). damage tires. Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet. high. Any obstruction restricting the access to a 10-to Obstruction removed to allow at 12-foot width for a distance of more than 12 feet least a 12-foot access. or any point restricting access to less than a 10- foot width. Road Surface Settlement, Potholes, When any surface defect exceeds 6 inches in Road surface uniformly smooth with Mush Spots, Ruts depth and 6 square feet in area. In general, any no evidence of settlement, potholes, surface defect which hinders or prevents mush spots, or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are more Road surface free of weeds taller Surface than 6 inches tall and less than 6 inches tall and than 2 inches. less than 6 inches apart within a 400-square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disposal Pavement petroleum hydrocarbons. in keeping with Health Department recommendations for mildly contaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. 1/24/2005 2005 Surface Water Design Manual -Appendix A A-10 APPEN!)JX A MAINTENANlT, RLQLJIREMENTS FLOW CONTROL CONVEYANCE. AND WQ FACILITIES NO. 24 -CATCHBASIN INSERT Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Catch Basin Inspection Inspection of media insert is required. Effluent water from media insert is free of oils and has no visible sheen. Sediment When sediment forms a cap over the insert No sediment cap on the insert Accumulation media of the insert and/or unit. media and its unit. Trash and Debris Trash and debris accumulates on insert unit Trash and debris removed from Accumulation creating a blockage/restriction. insert unit. Runoff freely flows into catch basin. Media Insert Water Saturated Catch basin insert is saturated with water, which Remove and replace media insert no longer has the capacity to absorb. Oil Saturated Media oil saturated due to petroleum spill that Remove and replace media insert. drains into catch basin. Service Life Exceeded Regular interval replacement due to typical Remove and replace media at average life of media insert product. regular intervals, depending on insert product. 1/24/2005 2005 Surface \\later Design Manual -Appendix A A-20 APPENDIX E Bond Quantity Worksheet Declaration of Covenant Facility Summary Sheet Site Improvement Bond Quantity Worksheet S15 Web date: 02/22/2013 l:.Q King County Department of Permitting & Environmental Review 35030 SE Douglas Street, Suite 210 Snoqualmie, Washington 98065-9266 206-296-6600 TIY Relay 711 Project Name: Rosa Meadows Location: 2724 Benson Road S, Renton, WA 98055 Clearing greater than or equal to 5,000 board feet of timber? ~~~~~~~yes If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 li-wks-sbq.xls x no For alternate formats, call 206-296-6600. Date: 2/12/2014 Project No.: Activity No.: Note: All prices include labor, equipment, materials, overhead and profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. Unit prices updated: 02/12/02 Version: 11/26/2008 Report n .. 1 .. : 2/1?/?n14 Site Improvement Bond Quantity Worksheet S15 Web date: 0212212013 Reference# EROSION/SEDIMENT CONTROL Number Backfill & compaction-embankment ESC-1 Check dams, 4" minus rock ESC-2 SWDM 5.4.6.3 Crushed surfacing 1 1/4" minus ESC-3 WSDOT 9-03.9(3) Ditching ESC-4 Excavation-bulk ESC-5 Fence, silt ESC-6 SWDM 5.4.3.1 Fence, Temporary (NGPE) ESC-7 Hydroseeding ESC-8 SWDM 5.4.2.4 Jute Mesh ESC-9 SWDM 5.4.2.2 Mulch, by hand, straw, 3" deep ESC-10 SWDM 5.4.2.1 Mulch, by machine, straw, 2" deep ESC-11 SWDM 5.4.2.1 Piping, temporary, CPP, 6" ESC-12 Piping, temporarv, CPP, 8" ESC-13 Piping, temporary, CPP, 12" ESC-14 Plastic covering, 6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2) Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4. 1 Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 Sediment trap, 5' high berm ESC-20 SWDM 5.4.5.1 Sed. trap, 5' high, riprapped spillway benn section ESC-21 SWDM 5.4.5.1 Seedinq, by hand ESC-22 SWDM 5.4.2.4 Sodding, 1" deec, level around ESC-23 SWDM 5.4.2.5 Sodding, 1" deep, sloped ground ESC-24 SWDM 5.4.2.5 TESC Supervisor ESC-25 Water truck, dust control ESC-26 SWDM5.4.7 WRITE-IN-ITEMS •••• /see oaae 91 Page 2 of9 li-wks-sbq.xls Unit Price Unit Quantitv $ 5.62 CY 6750 $ 67.51 Each 60 $ 85.45 CY 142 $ 8.08 CY 230 $ 1.50 CY 6500 $ 1.38 LF 1400 $ 1.38 LF $ 0.59 SY 5500 $ 1.45 SY 400 $ 2.01 SY 400 $ 0.53 SY $ 10.70 LF $ 16.10 LF 100 $ 20.70 LF $ 2.30 SY $ 39.08 CY 25 $ 1,464.34 Each $ 2,928.68 Each 1 $ 1,949.38 Each 1 $ 17.91 LF $ 68.54 LF $ 0.51 SY $ 6.03 SY $ 7.45 SY $ 74.75 HR 120 $ 97.75 HR 120 Each ESC SUBTOTAL: 30% CONTINGENCY & MOBILIZATION: ESCTOTAL: COLUMN: #of .O.nnllcattons Cost 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 37935 4051 12134 1858 9750 1932 3245 580 804 1610 977 2929 1949 8970 11730 $ 100,453.96 $ 30,136.19 $ 130,590.15 A Unit prices updated: 02/12102 Version: 11/2612008 R"port n,.1 .. : 211?1?n14 GENERAL ITEMS No. Backfill & Compaction-embankment GI -1 Backfill & Compaction-trench GI -2 Clear/Remove Brush, bv hand GI -3 Clearing/Grubbing/Tree Removal GI -4 Excavation -bulk GI -5 Excavation -Trench GI -6 Fencina, cedar, 6' hiah GI -7 Fencing, chain link, vinyl coated, 6' hiah GI -8 Fencing, chain link, gate, vinyl coated, 2 GI -9 Fencina, split rail, 3' hiah GI -10 Fill & compact -common barrow GI -11 Fill & compact-a ravel base GI -12 Fill & compact -screened topsoil GI -13 Gabion, 12" deep, stone filled mesh GI -14 Gabion, 18" deea, stone filled mesh GI -15 Gabion, 36" deep, stone filled mesh GI -16 Gradinq, fine, bv hand GI -17 Gradina, fine, with arader GI -18 Monuments, 3' Iona GI -19 Sensitive Areas Sian GI -20 SoddinQ, 1" deep, sloped Qround GI -21 Survevinq, line & qrade GI -22 Survevina, lot location/lines GI -23 Traffic control crew ( 2 flanners ) GI -24 Trail, 4" chinned wood GI -25 Trail, 4" crushed cinder GI -26 Trail, 4" top course Gl-27 Wall, retaininQ, concrete GI -28 Wall, rockery GI -29 Page 3 of 9 *KCC 27 A authorizes only one bond reduction. li-Wk!'.-sbq.xls Site Improvement Bond Quantity Worksheet Web date: 12102/2008 s,-,-,.-.,. ~,.--~,·--,~·,..,t' Existing Future Public Right-of-Way Right of Way & Drainage Facilities Unit Price Unit Quant. Cost Quant. Cost $ 5.62 CY 500 2,810.00 $ 8.53 CY $ 0.36 SY $ 8,876.16 Acre 0.35 3,106.66 $ 1.50 CY 500 750.00 $ 4.06 CY $ 18.55 LF $ 13.44 LF $ 1,271.81 Each $ 12.12 LF $ 22.57 CY $ 25.48 CY $ 37.85 CY $ 54.31 SY $ 74.85 SY $ 132.48 SY $ 2.02 SY $ 0.95 SY $ 135.13 Each $ 2.88 Each $ 7.46 SY $ 788.26 Dav $ 1.556.64 Acre $ 85.18 HR $ 7.59 SY $ 8.33 SY $ 8.19 SY $ 44.16 SF $ 9.49 SF SUBTOTAL 6,666.66 ' " ~ '-"'' Private Quantity Completed Improvements (Bond Reduction}* Quant. 6250 4.15 6000 450 1 250 21500 7 5 2.65 1200 Quant. Cost Complete Cost 35,125.00 36,836.06 9.000.00 6,048.00 1.271.81 5,642.50 20,425.00 945.91 3.941.30 4,125.10 11.388.00 134,748.68 Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n~te: 211'>nn14 I ROAD IMPROVEMENT No. AC Grinding, 4'wide machine< 1000sv RI -1 AC Grinding, 4'wide machine 1000-200 RI -2 AC Grinding, 4' wide machine> 2000sv RI -3 AC Rernoval/Disposal/Reoair Rl-4 Barricade, tvoe I RI -5 Barricade, type Ill (Permanent) RI -6 Curb & Gutter, rolled RI -7 Curb & Gutter, vertical RI -8 Curb and Gutter, demolition and disposa RI -9 Curb, extruded asphalt RI -10 Curb, extruded concrete RI -11 Sawcut, asphalt, 3" depth RI -12 Sawcut, concrete, per 1" depth RI -13 Sealant, asphalt RI -14 Shoulder, AC, ( see AC road unit price ) RI -15 Shoulder, gravel, 4" thick RI -16 Sidewalk, 4" thick RI -17 Sidewalk, 4" thick, demolition and disoos RI -18 Sidewalk, 5" thick RI -19 Sidewalk, 5" thick, demolition and dispos RI -20 Sian, handicao RI -21 Strioina, oer stall RI -22 Striping, thermoplastic, ( for crosswalk ) RI -23 Striping, 4" reflectorized line RI -24 Page 4 of9 *KCC 27A authorizes only one bond reduction. li-wks-sbq.xls Site Improvement Bond Quantity Worksheet Web date: 12/02/2008 Existing Right-of-way Unit Price Unit Quant. Cost $ 28.00 SY $ 15.00 SY $ 7.00 SY $ 67.50 SY $ 30.03 LF $ 45.05 LF $ 17.00 LF $ 12.50 LF $ 18.00 LF $ 5.50 LF $ 7.00 LF $ 1.85 LF $ 1.69 LF $ 1.25 LF $ -SY $ 15.00 SY $ 35.00 SY $ 29.50 SY $ 38.50 SY $ 37.50 SY $ 85.28 Each $ 5.82 Each $ 2.38 SF $ 0.25 LF SUBTOTAL Future Public Right of Way & Drainaae Facilities Quant. Cost 150 4,200.00 150 10,125.00 600 7,500.00 600 1,110.00 600 750.00 350 12,250.00 40 10.00 35,945.00 Private Bond Reduction* Improvements Quant. 1100 600 800 550 Quant. Cost Comnlete Cost 13,750.00 21,000.00 1,904.00 137.50 36,791.50 Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n::ite: 2/1 ?l?n14 Site Improvement Bond Quantity Worksheet Web date: 121021200s Unit Price Unit ROAD SURFACING (4" Rock = 2.5 base & 1.5" top course) For KCRS '93, (additional 2.5" base) add RS-1 AC Overlay, 1.5" AC RS-2 AC Overlav, 2" AC RS -3 AC Road. 2", 4" rock, First 2500 SY RS-4 AC Road, 2", 4" rock, Qty. over 2500SY RS-5 AC Road, 3", 4" rock, First 2500 SY RS-6 AC Road, 3", 4" rock, Qty. over 2500 SY RS-7 AC Road, 5", First 2500 SY RS-8 AC Road, 5", Qty. Over 2500 SY RS-9 AC Road, 6", First 2500 SY ,s -1 AC Road, 6", Qty. Over 2500 SY ,s -11 Asphalt Treated Base, 4" thick RS -1, Gravel Road, 4" rock, First 2500 SY RS -1, Gravel Road, 4" rock, Qty. over 2500 SY RS -1, PCC Road, 5", no base. over 2500 SY ,s -1 PCC Road, 6", no base, over 2500 SY ,s -1 Thickened Edge RS-1 Page 5 of 9 *KCC 27 A authorizes only one bond reduction. li-wks-sbq.xls $ 3.60 SY $ 11.25 SY $ 15.00 SY $ 21.00 SY $ 19.00 SY $ 23.30 SY $ 21.00 SY $ 27.60 SY $ 25.00 SY $ 33.10 SY $ 30.00 SY $ 20.00 SY $ 15.00 SY $ 8.50 SY $ 27.00 SY $ 25.50 SY $ 8.60 LF SUBTOTAL Existing Future Public Right-of-way Right of Way & Drainage Facilities Quant. Cost Quant. Cost For '93 KCRS ( 6.5" Rock= 5" base & 1.5" top course) 500 11,650.00 11,650.00 Private Bond Reduction* Improvements Quant. 2500 Quant. Cost Complete Cost 58,250.00 58,250.00 Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n~te: 2/1?/?/l14 Site Improvement Bond Quantity Worksheet Web date: 12/02/2008 I Unit Price Unit DRAINAGE (CPP = Corrugated Plastic Pipe, N12 or Equivalent) Access Road, R/D D -1 Bollards -fixed D-2 Bollards -removable 0-3 * (CBs include frame and lid) CB Type I D-4 CB Tyoe IL D-5 CB Type II, 48" diameter 0-6 for additional depth over 4' D-7 CB Type II, 54" diameter 0-8 for additional depth over 4' D-9 CB Type II, 60" diameter 0 -10 for additional depth over 4' 0 -11 CB Tvpe II, 72" diameter D -12 for additional depth over 4' 0-13 Through-curb Inlet Framework. (Add) D-14 Cleanout, PVC, 4" D-15 Cleanout, PVC, 6" 0-16 Cleanout, PVC, 8" D-17 Culvert, PVC, 4" D -18 Culvert, PVC, 6" 0 -19 Culvert, PVC, 8" D -20 Culvert, PVC, 12" 0 -21 Culvert, CMP, 8" 0 -22 Culvert, CMP, 12" 0 -23 Culvert, CMP, 15" 0 -24 Culvert, CMP, 18" D -25 Culvert, CMP, 24" 0 -26 Culvert, CMP, 30" 0 -27 Culvert, CMP, 36" D -28 Culvert, CMP, 48" 0 -29 Culvert, CMP, 60" D -30 Culvert, CMP, 72" D -31 Page 6 of 9 *KCC 27 A authorizes only one bond reduction. li-wk<:.-c:bq.xlc: $ 21.00 SY $ 240.74 Each $ 452.34 Each $ 1,257.64 Each $ 1,433.59 Each $ 2,033.57 Each $ 436.52 FT $ 2,192.54 Each $ 486.53 FT $ 2,351.52 Each $ 536.54 FT $ 3,212.64 Each $ 692.21 FT $ 366.09 Each $ 130.55 Each $ 174.90 Each $ 224.19 Each $ 8.64 LF $ 12.60 LF $ 13.33 LF $ 21.77 LF $ 17.25 LF $ 26.45 LF $ 32.73 LF $ 37.74 LF $ 53.33 LF $ 71.45 LF $ 112.11 LF $ 140.83 LF $ 235.45 LF $ 302.58 LF SUBTOTAL Existing Future Public Private Bond Reduction'" Right-of-way Right of Way Improvements & Drainage Facilities Quant. Quant. I Cost Quant. I Cost Quant. Cost Complete Cost For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe. 350 4 3 3,772.92 6 5 10,167.85 4 1 20 3 13,940.77 7,350.00 1,809.36 7,545.84 8,134.28 2,351.52 3,498.00 672.57 31,361.57 Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n~te: 2J1?nn14 DRAINAGE CONTINUED No. Culvert, Concrete, 8" 0-32 Culvert, Concrete, 12" 0-33 Culvert, Concrete, 15" 0 -34 Culvert, Concrete, 18" 0 -35 Culvert, Concrete, 24" 0 -36 Culvert, Concrete, 30" 0 -37 Culvert, Concrete, 36" 0 -38 Culvert, Concrete, 42" 0 -39 Culvert, Concrete, 48" 0 -40 Culvert, CPP, 6" 0 -41 Culvert, CPP, 8" 0 -42 Culvert, CPP, 12" 0 -43 Culvert, CPP, 15" 0 -44 Culvert, CPP, 18" 0 -45 Culvert. CPP, 24" 0-46 Culvert, CPP, 30" 0-47 Culvert. CPP, 36" 0-48 Ditchina 0-49 Flow Dispersal Trench (1,436 base+) 0-50 French Drain (3' depth) 0-51 Geotextile. laid in trench, polypropylene 0-52 Infiltration pond testinq 0-53 Mid-tank Access Riser, 48" dia, 6' deep 0-54 Pond Overflow Soillwav 0-55 Restrictor/Oil Separator, 12" 0-56 Restrictor/Oil Separator, 15" 0 -57 Restrictor/Oil Separator, 18" 0-58 Riprap, rlaced 0-59 Tank End Reducer (36" diameter) 0-60 Trash Rack, 12" 0-61 Trash Rack, 15" 0-62 Trash Rack, 18" 0-63 Trash Rack, 21" 0-64 Page 7 of9 *KCC 27A authorizes only one bond reduction. 1;_ .. ,1,.,_cbq.x\c::: Site Improvement Bond Quantity Worksheet Web date: 12/02/2008 Existing Right-of-way Unit Price Unit Quant. Cost $ 21.02 LF $ 30.05 LF $ 37.34 LF $ 44.51 LF $ 61.07 LF $ 104.18 LF $ 137.63 LF $ 158.42 LF $ 175.94 LF $ 10.70 LF $ 16.10 LF $ 20.70 LF $ 23.00 LF $ 27.60 LF $ 36.80 LF $ 48.30 LF $ 55.20 LF $ 8.08 CY $ 25.99 LF $ 22.60 LF $ 2.40 SY $ 74.75 HR $ 1,605.40 Each $ 14.01 SY $ 1,045.19 Each $ 1,095.56 Each $ 1.146.16 Each $ 39.08 CY $ 1,000.50 Each $ 211.97 Each $ 237.27 Each $ 268.89 Each $ 306.84 Each SUBTOTAL Future Public Right of Way & Drainage Facilities Quant. Cost 280 5796 165 4554 10350 Private Bond Reduction'"" Improvements Quant. Quant. Cost Complete Cost 700 14490 240 6624 93 3422.4 20 280.2 1 211.97 1 268.89 25297.46 Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n~te: 2/1?/?014 Site Improvement Bond Quantity Worksheet Web date: 12/02/2008 I Unit Price Unit PARKING LOT SURFACING No. 2" AC, 2" top course rock & 4" borrow PL-1 $ 21.00 SY 2" AC, 1.5" top course & 2.5" base cou PL-2 $ 28.00 SY 4" select borrow PL -3 $ 4.55 SY 1.5" top course rock & 2.5" base course PL-4 $ 11.41 SY UTILITY POLES & STREET LIGHTING Utility Pole(s) Relocation I UP-1 Lump Sum Street Light Poles w/Luminaires UP-2 Each WRITE-IN-ITEMS (Such as detention/water auality vaults.) No. Wl-1 Each Wl-2 SY Wl-3 CY Wl-4 LF Wl-5 FT Wl-6 Wl-7 Wl-8 Wl-9 Wl-10 SUBTOTAL SUBTOTAL (SUM ALL PAGES): 30% CONTINGENCY & MOBILIZATION: Page 8 of 9 *KCC 27 A authorizes only one bond reduction. I;"'""' "'bq.X1" GRANDTOTAL: COLUMN: Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements & Drainas:.e Facilities Quant. Quant. I Price Quant. I Cost Quant. I Cost Complete Cost Utility pole relocation costs must be accompanied by Franchise Utility's Cost Statement 1 15 78.552.43 23,565.73 102,118.15 B C 286.449.21 85.934.76 372,383.97 D E Unit prices updated: 02/12/02 Version: 11/26/08 Repnrt n,=,te: ?11 ?1?n14 Site Improvement Bond Quantity Worksheet Web date: 12/02/2008 Original bond computations prepared by: Name: Brianne Gastfield Date: 2/11/2014 PE Registration Number: Tel.#: 253-838-6113 Firm Name: ESM Consultin~ineers, LLC Address: 33400 8th Ave S, Suite 205, Federal Way_, WA 98003 Project No: ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND' PUBLIC ROAD & DRAINAGE Stabilization/Erosion Sediment Control (ESC) Existing Right-of-Way Improvements Future Public Right of Way & Drainage Facilities Private Improvements Calculated Quantity Completed Total Right-of Way and/or Site Restoration Bond*/*' (First $7,500 of bond* shall be cash.) Performance Bond* Amount (A+B+C+D) = TOTAL Reduced Performance Bond* Total ••• Maintenance/Defect Bond* Total NAME OF PERSON PREPARING BOND' REDUCTION: (A) (B) (C) (D) (A+B) (T) AMOUNT $ 130,590.1 $ $ 102,118.2 $ 372,384.0 $ 130,590.1 $ 605,092.3 Minimum bond' amount 1s $2000. BOND' AMOUNT REQUIRED AT RECORDING OR TEMPORARY OCCUPANCY ••• I (E} $ T x 0.30 $ 181,527.7 OR (T-E) $ 605,092.3 Use larger of Tx30% or (T-E) Date: • NOTE: The word "bond" as used in this document means a financial guarantee acceptable to King County. *"' NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. MAINTENANCE/DEFECT BOND' (B+C) x 0.25 = $ 25,529.5 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. REQUIRED BOND• AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DOES Page 9 of 9 Check out the DDES Web site at www.kingcounty.gov/permits I i_wlrc.,_sbq. vie., Unit prices updated: 02/12/02 Version: 11/26/08 R1>port n:at<>: 2/1?1?n14 RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF STORMWATER FACILITIES AND BMPS Grantor: --------------- Grantee: King County Legal Description:------------------------------ Additional Legal(s) on: ___________________________ _ Assessor's Tax Parcel ID#:--------------------------- IN CON SID ERA TION of the approved King County ____________ permit for application No. relating to the real property ("Property") described ---------- above, the Grantor(s), the owner(s) in fee of that Property, hereby covcnants(covcnant) with King County, a political subdivision of the state of Washington and its municipal successors in interest and assigns ("King County" and "the County", or "its municipal successor"), that he/she(they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 Form Revised 12/12/06 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: I. 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 pcrmit(s) #: ______________ . Stormwater facilities include pipes, swales, tanks, vaults, ponds, and other engineered structures designed to manage stormwater on the Property. Stmmwater 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 stormwatcr runoff on the Property. 2. King County 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 King County Code ("KCC") 9.04.120 or relevant municipal successor's codes as applicable. This right of ingress and egress, right to inspect, and right to perform required maintenance or repair as provided for in Section 3 be low, shall not extend over those portions of the Property shown in Exhibit "A." 3. If King County determines that maintenance or repair work is required to be done to any of the stormwater facilities or BMPs, the Director of the Water and Land Resources Division or its municipal successor in interest ("WLR") shall give notice of the specific maintenance and/or repair work required pursuant to KCC 9.04.120 or relevant municipal successor's codes as applicable. The Director shall also set a reasonable time in which such work is to be completed by the Owners. Ifthc above required maintenance or repair is not completed within the time set by the Director, the County 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 County's intention to perform such work. This work will not commence until at least seven (7) days after such Form Revised 12/ 12/06 2 notice is mailed. If, within the sole discretion of the WLR Director, 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 King County 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 WLR Director or equivalent municipal successors official may take measures specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair work completed hy the County 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. lflegal action ensues, the prevailing party is entitled to costs or fees. 6. The Owners arc hereby required to obtain written approval from the King County WLR Director prior to filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated stonnwater 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 King County and its Form Revise<l 12/12/06 3 municipal successors and assigns. This Declaration of Covenant shall run with lhe land and be binding upon Grantor(s), and Granlor's(s') successors in interest, and assigns. 10. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and King County or the municipal successor that is recorded by King County in its real property records. Forni Revised 12/12/06 4 IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of Stonnwatcr Facilities and BMPs is executed this __ day of _________ , 20 __ GRANTOR, owner of the Property GRANTOR, owner of the Property ST A TE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: -------------------·tome 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 Form Revised 12/12/06 Printed name Notary Public in and for the State of Washington, residing at My appointment expires _________ _ 5 KING COUNTY. WASIIINGTON. SURFACE WATER DESIGN MANUAL STORMWATER FACILITY SUMMARY SHEET Number -------- DDES Permit (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Overview: Project Name LaRosa -----·---------------------- Downstream Drainage Basins Major Basin Name Immediate Basin Name Flow Control: Duwamish -Green River Black River ------------ Date 2014-04-15 LaRosa Pond Flow Control Facility Name/Number ______________ _ Facility Location NW corner of the overall site ------------------ 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: 1 ponds ponds vaults tanks --- tanks trenches ------ Control Structure Location West side of Pond Type of Control Structure ______ 6_· _o_o_f_t_. _____ Number of Orifices/Restrictions 3 Size of Orifice/Restriction: No. J 2 · 50 in· No.2 1.75 in. No.3 7.00 in. (weir) No. 4 -------- Flow Control Duration Standard (Forested) Flow Control Performance Standard ______________ _ 2009 Surface Water Design Manual 1 119/2009 KING COUNTY, WASil!N(iTON. SURFACE WATER DESIGN MANUAL Live Storage Volume _3_8_' 9_0 _6 _c_f_. __ 5.3% Number of Acres Served Number of Lots 7.10 ac 21 Depth --------- 6.00 ft. ----- Dam Safety Regulations (Washington State Department of Ecology) Reservoir Volume above natural grade ______ _ Depth of Reservoir above natural grade ______ _ Facility Summary Sheet Sketch Volume Factor of Safety All detention, infiltration and water quality facilities must include a detailed sketch. ( 11 "x 17" reduced size plan sheets may be used) 2009 Surface Water Design Manual 2 1/9/2009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MAt,;UAL Water Quality: Type/Number of water quality facilities/BMPs: biofiltration swale large) above --- (regular/wet/ or continuous inflow) large) ___ combined detention/wetpond --- ( wetpond portion basic or large) combined detention/wetvault ___ filter strip ___ flow dispersion ---farm management plan ___ landscape management plan ---oil/water separator (baffle or coalescing plate) Liner? --------- X catch basin inserts: ------ Manufacturer Contech ___ sand filter (basic or large) sand filter, linear (basic or --- ___ sand filter vault (basic or sand bed depth, ___ (inches) stormwater wetland --- X stonn filter --- ___ wetpond (basic or large) wetvault --- ___ Is facility Lined? If so, what marker is used -------------------- ___ pre-settling pond ___ pre-settling structure: Manufacturer -------------------- __ x_ high flow bypass structure ( e,g,, flow-splitter catch basin) source controls --- Design Information Water Quality design flow __ o_,_3_2_c_f_s ________ _ Water Quality treated volume (sandfilter) _______ _ Water Quality storage volume (wetpool) Facility Summary Sheet Sketch 2009 Surface Water Design Manual 3 1/9/2009 KING COUNTY, WASl\11\GTON, SURFACE WATER DESIGN MANUAL All detention, infiltration and water quality facilities must include a detailed sketch. ( 11 "x 17" reduced size plan sheets may be used) 2009 Surface Water Design Manual 4 1/9/2009 ~ ' ~ l "' (/) 0 a: <ti ..J A PORTION OF THE NW 1/4 OF SECTION 29, TWP. 23 N., RGE. 5 E, KING COUNTY, WA CB f2A, --...;;,~ 2 43·,. 1 W sc1_11:' '.''.·'~flllC LID IJ-1 E,;i1 I LC3 ~E~ 3 ~~.~;~ ,- 9 lH1S Sll[[T, I STORMF'ILTER-MANHOL~ 'h · 13~1); "3 C:=130204.:.-g • '>ff F'PO~ _C: St-~ET 1"1'·1~ CB #ZB. -(p( 2-4e";i _' OVEF'l::;w '.,ffUCTLP[ W .C.EECC "°'I l-1=15910E ·s r -·, .OC2D85 . .36 SEE P~Jf-11' IHl'.o SIIC:[~ I ~g~~L Fg;c:~clt~f l \ I :0\1-u; I ~,\ . L '~ ... , ,, " STORMGATE. MANHOLE . ',// ·," 1 1--·u11,:,.-c ·,' '"-.. ' -1.·L>;C.:-, --1 '- ('I I I , Sl_f ... F8F.Lt lrll:-0 :+: [-r .... I_ ~l.~1-S[[PAr;-_·:;,M;-~ 2E~ CE-AIL T•II:, _,11[':l '· / '-1 1: :E~~/ ,, :i w ; :,~"¥ I~:::~ .'.:~?~e.c: 1 ~1.llril'.''.Of.'_[T . -· --------, (!· (:' l.~.P~}i~~ ~I:':· SHE::T @·~;, 1 e-., H'C~'L[ :1-c:E- (J, 1;:: LF 1 ,:/'q T '~ 'cH f.-'-':)FIL[ -,115 ~nEE"i ,-4,1 ·~ LC. IP."\'> SL• ' -SC:E :0;:!0f 1 L~ THIS °'-If fl :3_ ~;[ -~p~ftE '.~l~'S SHf c I (~-, ~~[L~f'~t1~~'.: ·~:EET Pl.-( ,'f', 11 Lf", 1 2··; 'ii '.J SEE PPO~l..f SHEET Pl1-(J.J =~.;.," ,I~~ t J::,. -H'S S1-LET . cy l:s A • , ""'· ·-...., ~'v.: ,, / ·," ,, .s'o --. ~. It, I:,, -, • Tl) ', '5'~ '---"-...., :CB #5 S'.:E SHEET ":'-'1" Pf~ -'_i\l-1 ----t -...'.TJI=---. l_~' 11 i--·.~11,_;,' ~!l_~I-;,~,_., ~. ,-:,,~i_l;!,~.~,-~' .~,-~,,~u_~,-:J~,,~,-~,.-~'q-;;.ll_~·-~. ;.1~, ,~_;;ii ,~_< .. , =-11 I=--. 'e'-"1~- -'ll=Ll.!· 1lfl~-~-·----Cal 2 WOl'trg D&yv 8',fr,r9 YOU Dig 811 vtittm Under;rOl.l'ld Location Cenler (O.MT.ND.ORWA) 1-1/7'· CK'-'S•l[D 5L'<i'ACE-/ JCP C(/LJRSE 2-' /2'' CRLSI-EC-S\;<;~ACE GASE COUFSE POND ACCESS ROAD "01 TO 3CALE CSSU.L CQ~S<"Tl~<O EH<11t.1•::~ &> 1 ~ i==t::iFcn ~=::•,mo><ou,•, 1 • I IS' I. I '"°""'"'"Y·#t"'""'" v.ww.e~-r,c";1.ccn, ;:~,,.'·;~.::" I "'°'·""';;:;•·"•-o, ""'"'"' "'""""" ""'"' ,.,,,,,._,.., ,..,-.,..,_ ,,,.,..,_,,.. ·~· ~-"""' ,~ ... ,.-, .. +."-~ ESM JOB #1670-004-013 I CB #6 '.'EE S·JC:[T ,-f '~EPCE'·I~ I I I I - I -- / OV[PFLCW W_'; / ELEV=42~ 20 I B ------- '.::;-· ,·'-... CB #7 ~/ SEE SHEET PD-Uj ,. ~ [LA'·' BACKf ~ I ;i J /'?=~"' ( I~) '-._ _ _}_/ ' / ANTI-SEEPAGE COLLAR DETAIL tJCT TO SCALE t-1() P[VISIOM A / 8> -f'f'U,IECT GC:i_.'1[,A'<· ,- I I 11 1 1 ~ I 111 2 L-...;. 1-- ----6-· =-,_,,,; 21 "' n SCALE: 1" -20' ~..J 70 1 Q D 440 430 425 420 C.~1 ~"1' ii~ .z"" ' ,'--'I m, I ' ' I ' ' I ' ' I ' ' 11 LF. ·5"i st, @ 5~4) :J~% \ I/' ./, i I ,0 e·:,r 1c """"'I '° F~IJ·:C: - LF. Hf'ii, ~·=· -c,=0~ N-HI SEEP--' CO, I AP SEE :,CTAIL Tr:IS SHEET 435 430 425 420 415 410 3+00 1;:' PCliG --------+ l,C,:[C·~· POA~ f! fV-.'..'.'8.J(, / [:,:15T1t1G 0R\)lll•1D-._ rmm Fc:11r:E ----' / i 12' PC:Hf, r--,r--,\((ESS °CA: fLEv=i20.cc, rm,:<. ,,,, [:_'.:v~.12~:r)~, r, '. ~., ~·~'f 1. -,T~•f'M.' t'CI I[ · 11 : f I ,, 1 fl.· 3--~•.'.:0'.Z _;~r ,~, '·f ;: r,f-)t,}- ',,':=; 1:::, ·,,[- i•: TF•,\'.:,t 1 I r;IC-. .'1 u ;,·.i·,r ';\' IE-; '.'.C·--2·0 If =--l rn·si I[-I 2--l H~ H~ ffW 4+60 POND CROSS SECTION 8-13 SCALE: E, •Sl111C ,:-~().JI 11; ;;,,:::,1,10 c,_,T _~T .-v-·1r·A:;~p:i-c.~ E. = .<.7:-1.'.:.D. Hf'c '-/ "">>._ vrr-r :::£S ,:;·1 W.':,. ELEV~-1:::E '.:J \ ( ',\·/, )I;:;, --1 <I 1 ~, f-'"· I I'. ~/ ~~EV=-'-20_:,:, 1-PP0P03[L Gr:-t,D[ 415 srnni::;.I.TE MAIJhOI f TG=•12:C.•)Q ::;G TYP:: 2 f.::to :_-UI. SF~11.:TJPt ·1-1 81~X:AGE 410 1+00 1[=47[; 7(1 12"'\l 1[=42C 20 18°·\l C_[ #_LA,_ TfP[ 2-48"0 w/sr:111J LO(' :-JC LIC TG=-420.S- C-'115.5~ 'E'"~ 1+40 TG=42C.8C 1[-'-2050 'E."~ '.;8 #2B, T'!P_[ 2--:'>_8'',;, CVEFF_DW Sl"IJCILJRE 'w/0'.:BF<IS C,\G[ TG=42 7.20 ll~420.•11 113··.z. 1+80 2+20 2+60 PON[) CROSS SECTION A-A SCALE: ~.=;::-~o:;z· 3+00 4+00 435 430 425 420 415 410 440! 430 425 420 415 410 _m_ __ CHCKf J ro~· ·~0MPLl,\'iC[ :;1T· ~.-.csr,~-N'D'.", POND VOLUMES CETD·ffl0~1 'G:;L. PED 3b,1J.1b CF Pr'CVIDEC 35.::!06 CF Cal 2 Working D8}'8 Belore You Dig 811 Ulllin ~d Location Co,n\or {D.MT,1£1.0R. WA} DC><><[t,'BNQ 1·-20· ~ !R CITY Clf PEIHC•J La Rosa I {)-4;15/201,4,I POND A PLAN, CROSS SECTIONS & DETAILS"-"' ""'"''.,.,.. PN-01 1----------"2':_~e> .. f'lc~n,ng :Bu i,Jin~/F'~bl,c l'/,;,rk~ C-t"r,'. llAlf I APPF ,. 17 "'·.lJ APPENDIX F StonnRlter Manhole and Stonngate Calculations and Worksheets Ct1>NTECH' ENGINEERED SOLUTIONS CONTECH Stormwater Solutions Inc. Engineer: Date Site Information Project Name Project State Project Location Drainage Area, Ad Impervious Area, Ai Pervious Area, Ap % Impervious Runoff Coefficient, Re Upstream Detention System Peak release rate from detention, 0,e~ase peak Treatment release rate from detention, O,e,ease ,,eat Detention pretreatment credit (from removal efficiency cal cs) Mass loading calculations Mean Annual Rainfall, P Agency required % removal Percent Runoff Capture Mean Annual Runoff,V, Event Mean Concentration of Pollutant, EMC Annual Mass Load, M,otal Filter System Filtration brand Cartridge height Specific Flow Rate Number of cartridges -mass loading Mass removed by pretreatment system, MP"' Mass load to filters after pretreatment, M,,.,,1 Estimate the required filter efficiency, E,." Mass to be captured by filters, M,,e, Allowable Cartridge Flow rate, O,art Mass load per cartridge, M,art (lbs) Number of Cartridges required, Nmass Treatment Capacity Determine Critical Sizing Value Number of Cartridges using Oce~ase tceat, N11ow Method to Use: SUMMARY Treatment Flow Rate, cfs Cartridge Flow Rate, gpm Number of Cartridges Determining Number of Cartridges for Systems Downstream of Detention EJJ 4/10/2014 Rosa Meadows Washington Renton 7.10 ac 3.98 ac 3.12 56% 0.55 1.17 cfs 0.32 cfs 50% 38 in 80% 90% 488,763 ft 3 70 mg/I 2134.58 lbs StormFilter 27 in 1.00 gpm/ft' 1067.29 lbs 1067.29 lbs 0.60 640.37 lbs 11.25 54.00 lbs 12 0.30 cfs 13 HYDRAULIC 0.32 11.3 13 1 of 1 C(>NTECH' ENGINEERED SOLUTIONS StormGate Hydraulic Calculations Prepared by Eli Jefferson April 11, 2014 Preparer Initials AS Project Name: Structure ID: Site Flow Rates Treatment Flow, Qtreat Peak Flow, Qpeak StormGate Size System Type Manhole Diameter Weir Wall Length, Lwa11 Weir Length, Lweir StormGate Hydraulic Calculations StormGate System Info: Invert In Elevation, IE In Invert In Pipe Diameter Low Flow Invert Out Elev, OutLOw Low Flow Pipe Diameter, DLow Low Flow Orifice Dia meter, 0 0 Orifice Type Area of Orifice, Ao Invert Out Elevation, IE Out Invert Out Pipe Diameter Low Flow through Orifice StormGate Weir Elev Rosa Meadows 201 0.32 cfs 7.90 els Manhole 4.00 ft 4.00 ft 3.00 ft Provided by the Engineer Provided by the Engineer =Manhole Diameter Length of StormGate adjustable weir 420.20 ft Provided by the Engineer 18 in Provided by the Engineer 420.20 ft Provided by the Engineer 8 in Provided by the Engineer ~--5-in-~!Selected by CONTECH Stormwater Solutions plate Selected by CONTECH Stormwater Solutions 0.14sf =Pi*D0 2 /4 420.20 ft Provided by the Engineer 18 in Provided by the Engineer 0.32 els =0.61•11o•(2•g•(Weir Elev-(Out,0 w+Do/24)))'" 420.64 ft 420.64 hidden, to round to nearest 100th Check Weir Elev> Top of Orifice OK StormGate During Peak Flow: WSE downstream, WSEd-peak Is SG Weir Elev< WSEd-peak: Weir Coefficient, C Qpeak Head loss over Weir, H Upstream WSE in SG at Qpeak Flow through Orifice @ Peak No.of Flowspreaders in StormFilter Check Flow through Orifice Additional StormGate Elevations: Rim Elevation Floor Top of Weir Wall Total depth Top of Pipe Elevation Check if Surcharged Conditions OK 0.00 ft 3.33 7.90 els 0.81 ft Assuming Free Discharge Check for submerged weir conditions =(C*Lwe/H 1 ·5)+(C*(Lwa11·lweir)*(H-6/12) 1 · 5 ) ~4~2~1~.4~5~ft~~l=SG Weir Elev+ H 0.68 els 1 OK 425.00 ft 418.97 ft 421.14 ft 6.03 ft 421.70 ft OK =0.61.A'(2•g•(WSEpeak -(Ou\~ +Do/24))) 112 =Check that Flow through Orifice @ Peak < 1.80cfs * No. of Flowspreaders Provided by the Engineer =Lower of (StormGate Weir Elev -20") or IE Out =StormGate Weir Elev + 6" =Rim -Floor =IE In+ Pipe Diameter If Pipe is surcharged, Engr to confirm design 12021-8 NE Airport Way Portland, OR 97220 ©2006 CONTECH Stormwater Solutions contechstormwater.com Phone: 800-548-4667 Fax: 503-258-3190 1 of 1