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Home My WebLink AboutLUA-06-020_MiscKennydale Cafe PRELIMINARY SURFACE WATER TECHNICAL INFORMATION REpORT January 19,2006 I8'JlRES J2 . z,? 0 e,,! Prepared by: LPD Engineering, PLLC 7936 Seward Park Avenue South Seattle, WA 98118 Contact: JeffLarnoureux (206) 725-1211 Prepared for: Pool Brothers Construction POBox 3023 Renton, W A 98056 Contact: Matt Pool (253) 405-3475 • TABLE OF CONTENTS SECTION I-PROJECT OVERVIEW ................................................................................................................................ . SECTION 2 -PRELIMINARY CONDITIONS SUMMARy ............................................................................................. . SECTION 3-OFF-SITE ANALySIS ................................................................................................................................... . SECTION 4-FLOWCONTROLAND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................... . SECTION 5 -CONVEYANCE SYSTEMS ANALYSIS AND DESIGN ......................................................... . SECTION 6 -SPECIAL REPORTS AND STUDIES ....................................................................................... .. SECTION 7 -OTHER PERMITS ....................................................................................................... . SECTION 8 -ESC ANALYSIS AND DESIGN ................................................................................ . SECTION 9 -BOND QUANTITIES/FACILITY SUMMARIEs/ DECLARATION OF COVENANT ..... . SECTION 10-OPERATIONS AND MAINTENANCE MANUAL ................................................................ . FIGURES D Figure I (a. b, c) TIR Worksheet ............................................................................................................................ . D Figure 2a Vicinity Map................. ....................................................................................... . .......................... . n Figure 2b Parcel Map.................... ........ ... ... . .................................................................................................... . U Figure 2c Existing Conditions Map ....................................................................................................................... . D Figure 3a Drainage Basin Map...... . ...................................................................................................... . IJ Figure 3b Developed Conditions Drainage System Map ..................................................................................... .. n Figure 4 (a. b) Soils Map and Legend .................................................................................................................. .. D Figure 5a OjfSite Analysis Drainage System Table................................................... .. ........................... .. D Figure 5 (b, c) OjfSite Downstream Drainage Map ............................................................................................ .. D Figure 6 (a, b) Stormwater Facility Summary Sheet .............................................................................................. .. D Figure 7 (a, b, c) Conveyance System Analysis and Sizing Table .......................................................... .. D • Appendix A Design Drawings ...... .. .................. . • Appendix B Geotechnical Report. .. ........... .. • Appendix C Design Calculations and Supporting Information -F t7 ./" C--1- Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Address -+:p.---'-:Ll;!'x"~..2$;L£.<....;:l'-r:-'4-"!:.li-"-'-'r-"'CJ" Phone __ ~~~~~Z-~2-~~ ______ _ Project Engineer .. ~~tf:. __ Jd,~<u'.JL~:.2:'-----_ com~y~L~~~~~~~~~ __ ~ Address Phone -'S-,-=""""-:-',-=-,,,?=.:,,::-~::-'--o~o--. PART 2 PROJECT LOCATION AND DESCRIPTION Project Name tr J1 Ii 1 ,/c... Ie- Location t Township '2--?/J Range GG Sadlon ~~5L-____ __ Project Size 12 ( '18 AC ,.pr--- Upstream Drainage Basin Size ---''f-\C---AC PART 3 TYPE OF PERMIT APPLICATION PART 4 OTHER PERMITS D Subdivision . o Short Subdivision D Grading ~ Commercial o Other _____________ _ D DOF/GHPA D COE404 D DOE Dam Safety D FEMA Floodplain D COE Wetlands PART 5 SITE COMMUNITY AND DRAINAGE BASIN Community Drainage Basin t c<. t. (, tJ,f( ~;, ;: ... ' : ! ~ /1 £ . PART 6 SITE CHARACTERISTICS -&1 --- Shoreline Management Rockery f~ f~ .... '7 Structurai Vaults Other HPA DRiver ________________________ _ D Floodplain _____________________ _ D Stream ____________________ _ o Critical Stream Reach o DepressionslSwales D Lake -__ -;-__ -,--,---,---,-__ ~ Steep Slopes d>k f/;" h· j .J/of~ o LakesidelErosion Hazard £: " ,f "'A I' f' 0 rJ PART7 SOILS Slopes ,'7 U-JIJ "'It' 4-r/ I ,'7 7 o Additional Sheets Attatched D Wetlands --____________________ _ D SeepslSprings '0 High Groundwater Table D Groundwater Recharge D Other Erosion Potential Erosive Velocities 1/90 [, '1 rI/e i Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PART 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT J:Zf Ch. 4 -Downstream Analysis D D D D D D AdditiorIaJ Sheets Attatched PART 9 ESC REQUIREMENTS MINIMLfv1. ESC REQUIREMENTS DURIN~ CONSTRUCTION Sedimell)tation Facilijies Stabiliz.id Construction Entrance Per·im"ter Runoff Control Cle,arh,d .ind Grading Restrictions Other D Tank ~Vault N la MINIMUM ESC REQUIREMENTS FOLLOWING CONSTRUCTION Stabilize Exposed Surface Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris Ensure Operation of Permanent Facilijies Rag Umils of NGPES Other Method of Analysis 513 v 1-1 D Energy Dissapator D Wetland D InfiHration D Depression D Flow Dispersal D Waiver CornpensationIMiligation of Eliminated Site Storage D Stream Brief Descripti(jIn of System Operation rl/U "a!. uI~ .. /- C'" -1 (,: D Regional Detention h-,<;/, ,It '1<-$'151,.."" Facility Relate!:! Site Umilations Reference . Facility Umijation D Additional Sheets Attatched PART 11 STilUCTURAL ANALYSIS (May require ,p"cial structural review) D Cast in Place Vault D Other r3' RetainingiWall D Rockery>4'High D Structural On Steep Slope PART 14 SIGNATURE OF PROFESSIONAL ENGINEER PART 12 EASEMENTSrrRACTS D Drainage Easement D Access Easement D Native Growth Protection Easement D Tract D Other I or a civil anglneer under my supervision have visited the site. Actual CJ' ./ Site conditions as observed were incorpor_ into this worksheet and the . J .... attatchments. ·To the best of my knowledge the information provided -;...d:~~~~~~~~~~ here is accurate. ~ 1 KV\ SECTION 1 This Storm Drainage Report addresses the eight core and five special requirements of the King County Surface Water Design Manual, 1990 (KCSWDM). A Level I downstream aualysis is also included, Note that this Storm Drainage Report is a conceptual preliminary report. The report will be finalized after site design has been finalized and prior to site development pennit Overview The proposed development is the construction of a multi-use 3 story mixed use building with associated parking, Given the topography of the existing site, a number of structural retaining walls will be included in the proposed design, To minimize the impact to the steeper portion of the site to the west, proposed improvements are located as far to the east of the property as is feasible, The building has been sited fronting the street as encouraged by land use to facilitate pedestrian access and enhance the aesthetic of the street Existing site The existing site slopes up from a low point along Lake Washington Blvd westerly towards the 1405 right of way. The slopes vary from 15% up to 40% and greater (Please note that a protected slope exemption has been granted for this project). The eastern portion of the site has an average slope of 17%. The site is in an Aquifer Protection Zone 2. The existing site is currently undeveloped. lbe site is vegetated with some large matnre trees, primarily 8" to 12", The site appears to be second growth with an under story of blackberry and other invasive vegetation. The site soils are brown, gravelly sand which appears to allow some infiltration; a soils investigation has not yet been done for the project, but will be prior to pennirting. Based on the surveyed topography and site observations, the existing site appears to drain via surface mnoff across Lake Washington Blvd. The roadway is super-elevated fronting the site and there is no ditch along the east side of the road. Proposed site The proposed development will construct approx. 12,000 sf of impervious area subject to vehicular use. Parking lot mnoff will be collected in catch basins and routed through a water quality treatment facility. Discharge from the water quality facility will join the tightlined drainage from the building downspouts and be routed to the existing storm drain which is located in the unimproved Morgan Ave. (NE lOth ST) right of way just north of the property. (See Figure 2-Vicinity Map). Based upon the King County Soil Survey maps the site soils are Alderwood and Kitsap soils (AKF) (See Figure 3a & 3b -Soils Map. Stormwater Improvements Per the City of Renton, the project is subject to the requirements of the 1990 King County Surface Water Design Manual with City of Renton Amendments. The project is located within a Zone 2 Aquifer Protection Zone, Based on these requirements, the project will provide a water quality treatment facility for mnoff from impervious areas subject to vehicular use. The project will create a negligible increase in peak rate mnoff so detention will not be required. See Section 2 and Section 4 below. E Q o " N o CO CO o I c o ~ i i t I /.ake Washingt.on ,jlliftl • , ;II \ rer .\ ~rOject -,.,.~ ',"'.c,'_---, o i~~~~-~~~:~~::~~;~;i;De;sc;r;Pt-~;on~~---:C ----------------~--~~~~~~~=·=·~":,,,·~-=··:-1K£-.~~e"~~nn'~--~~:.I---~d~r·~~;g~gr~~-~~c~.a~'Ie~e ~ LPDENGINEERlNG,PLLC Vicinity Map 2 ~ ~ 7936 SEWARD PARK AVENUE S. ~1:S:E~ATT~L~E~W~A:SH~'N~GT:O:N'~9~81~18~~~ __ ~ ______________________________________________ -L __________ __ ~ LH' 206.725,1211 FAX, 206.725,1211 IS part of . of Scale 1 :24 000 )< 'Vri /21 d q"./~ L a./<-,co ~ 5t/S /C-L 5 .. , 0/ >.t;;:;~·3°'·~to"o .;::-, '.. ,./ /" t:: .5 "C.- U. S. DEPARTMENT OF AGRICULTURE SOil CONSERVATION SERVICE SOIL LEGENO The fint (op;lol leller 15 the ..,irial one of Ihe soil nomoi!!. A SltcOl"ld capital lett~, A. 5, C, D, E, 0( F, indIcates t~ class of slope. Symbols without a slope letler ore r!,os<!' of nearly l",v .. 1 !'.ods. SYUBOL AgB AgC AgO "F AmB A",C Ao BeC BoD SoF Bh S' Bu Cb loA 10C 10D <pS KpC KpD K.C Mo NO<: Ng N' No p, Pk Pu Py RoC RoD RdC RdE R. Rh NAME Alderwood gravelly sandy loam. 0 to 6 po. ... c .. nt slopes AJder ..... ood grovelly sa",qy iOgm, 6 10 15 p!!'fce",r sJopo!s Alderwood grovelly SQndy loom. 15 fo 30 perce'" ,Jopes Alder .... ood and I(i.sop soils, ~ .. ry Meep Ar .. "'~. Ald .......... ood mater;",., 0'06 percenl slope ... Arenr~, Ald" ........ <><>d mo1erool, 6 to !::. percent "10,,,",5 * Ar ... ,,'s. E v ..... " m(lr ..... 'oJ- 8 .. ou,,, .. gravelly sandy loom, 6 to 15 perc.nt :s.l~s BeQ<Jsite graveUy .. GOd.,. loam, 15 to 30 percent 'Slopes Beausi ... gravelly !:Qndy loom, 40 to 75 percent slopes 3ell'I"l<Jham sd. loam 3,,~car ~d, loam Buckl .. ~ sil, IOQrn Coaslal Beaches Eadmon. sill loam Edgew'ck f,n .. sandy l()CIm E".,.rert gra"ell~ s<;Indy loom, 0 fa 5 p.ei'c...,.t slopes E .... er" " 9ra" .. lly sandy l()CIm, 510 15 ~c_1 $IO~5 E .... ~r .. tI gro ...... ll y s'lody IOQm, 15 r~ 30 perce-nt sloP<ts E"",e,.-Aldecwood g,ovelly sandy looms, 6 to 15 percent slapes Ind,onolo loomy f,ne $Clnd, 0 to./l pe-rcent SlClf.>Oi!5 Ind'onolCl loamy fine-sand, 41015 percent S/Clp$'S Indionola 100my f'ne sand, 15,030 percent slopes Kinop silt loam, 2 to 8 f.>Oi!rcent slOjlO!ls Kils"p sil. I<XIm, 8 10 15 percent slopes K"SOP sill IOQm, 1510 30 percen' $loP<ts Klaus gra"elly loamy sand, 610 15 piir'cer>t slClPGs Mix .. d alluvial rand NeilTon .... ery grayelly loomy SClnd, 2 to 15 perCent slopes N<.wberg sd, loam Nooksack silt 1000m NOI"mQ sandy lcom Orcas pea. Or-idia sib loam Ovoll grovelly loom, 0 to 15 percent slopes Oval/gravelly loom, 15 to 25 percen' slopes Ova/! gravelly loom, ./10 to 75 percenr slopes Pile huck loamy fine sand P·"ehuck fin.,. sandy 10000m Puge. s.if.y day loam Pvyo/Jup fine SQ'ldy loom RClgnQr fine sandy loam, 6 to 15 pMcenr slapes Rogno, fine sQndy loom, 151025 perc,",' slopes RagnQr-IndionalQ QSSOCiCltOon, sloping. Regnor-lndianalQ OSSOclOlion, mode-rotely STeep- R.nton S; I. I C>om Riyer-osh Solol sill 1000m SommrJmish silr lOam SeQrtle mlJCk Sm ShoJcOT mv.::J. Sn Si s >It IOQm So. Snohom'sh sil. loom Sr SnohomIsh slit iOQm, t"iel<: surfac:e .... orlOnl Su Sullon silt loom Tu Tukwila muc:k Ur Urban rond Wo Woodinvdl .. silT 10000m • The compos,hon of tht\fs,", ,m"~ SECTION 2 Conditions and Requirements Summary This section addresses the requirements set forth by the King County SUlface Water Management Design Manual (KCSWDM), 1998 Edition, Core and Special Requirements listed io Chapter I. I. Discharge at natural location (1.2.1): All flows from this project site will remaio io the natural draioage patterns withio a quarter mile downstream of the project. See the off site investigation included in Section 3 of this report. 2. Off-site Analysis (1.2.2): An off site investigation was preformed for this project and is included io Section 3 of this report. 3. Runoff Control (1.2.3): The project is within the Lake Washington E draioage sub basin and is not subject to special runoff volume controls. The proposed project site post-developed peak runoff rate for the 100 year, 24 hour duration design storm event is calculated to be less than 0.5 cfs more than the peak runoff rate for the existing site conditions so on-site nmoff control will not be required for the proposed project. The calculated peak runoff rate for the 100 year 24 hour duration design storm events are as follows: Existing 100 year peak ~ 0.38 cfs Post-Developed 100 year peak ~ 0.46 cfs Net change in 100 year peak rate ~ 0.08 cis The proposed project will result in surface water runoff from more than five thousand (5,000) square feet of impervious surface subject to vehicular use. Per COR code 4-6-030 E.3.b this impervious nmoff sbalI be treated prior to discharge with biofiltration measures. A biofiltration swale design was evaluated, but we are requesting that the City of Renton consider an alternative method of treatroent. See Section 4 of this report for additional information and justification. 4. Conveyance Facilities (1.2.4): The project includes a tight line conveyance system in the proposed parkiog lot that will collect onsite drainage and route it through the stormwater treatroent facility. Per City of Renton Code 4-6-030 E.3.g., any open channel may require a liner to prevent groundwater contamination. A complete conveyance analysis will be included in the fmal TIR. 5. Erosion/Sedimentation Control Plan (1.2.5): A full TESC plan will be included with the permit submittal and wilI be in accordance with the 1990 KCSWDM requirements. These plans will be considered the miuirnum for anticipated site conditions. The Contractor will be responsible for implementing the all TESC measures and upgrading as necessary. The TESC facilities in place prior to any clearing, grubbing or construction. 6. Maintenance and Operation (1.2.6): The final TIR will include maintenance and operations guidelines for all of the proposed draioage facilities, including the water quality treatroent facility and the conveyance system. 7. Financial Guarantees and Liability (1.2.7): This Core requirement is specifically required for a project constructed and permitted in King County and is not applicable for the City of Renton. City of Renton requires bonding for all street and drainage improvements. The Owner will post a bond equal to 120% of the estimated value of improvements~ prior to construction frontage improvements. An engineer's estimate of probable cost will be included in the permit submittal TIR. Special Requirements I. Critical Drainage Areas -Project is not within a designated critical drainage area. 2. Compliance With An Existing Master Drainage Plan -Project is not withio an area covered by an approved Master Draioage Plan. 3. Conditions Requiring A Master Drainage Plan -Project is not a Master Planned Development, a Planned Unit Development, a subdivision with at will bave more thao 100 lots, a commercial development that will construct more than 50 acres of impervious surface, or will not clear more thao 500 acres withio a draioage sub-basin so a Master Draioage Plan is not required. 4. Adopted Basin Or Community Plan -Project is not withio an area with an adopted plan. 5. Special Water Quality Controls -The project proposes discbarge to a conveyance system that eventually outfalls to a stream that runs through Gene Coulon Beach Park and discbarges to Lake Washington. See Section 3 Off Site Analysis. Water quality treatment for impervious area subject to vehicular use will be required as indicated by City of Renton codified amendments to the KCSWDM as noted above. 6. Coalescing Plat DillWater Separators -"lbe project will not construct more than 5 acres of impervious surface. 7. Closed Depressions -Proposed project ""ill not discharge runoff to an existing closed depression. 8. Use of Lakes, Wetlands or Closed Depressions for Peak Rate Runoff Control -The project will not use a lake, wetland or closed depression for peak rate runoff control. 9. Delineation of 100 Year Floodplain -The Proposed project site does not contain or abut a stream, lake, wetland or closed depression. 10. Flood Protection facilities for Type 1 and 2 Streams -The proposed project does not contain or abut a Class 1 or 2 that bas a flood protection facility. 11. Geotechnical Analysis and Report -A geotechnical analysis should not be required for the construction of the stormwater facilities, however a geotechnical study will be performed for the site and the Engineer will include information regarding draioage recommendations. A copy of the geotechnical study will be included in the fmal TIR. 12. Soils Analysis And Report -The soils analysis will be included in the geotechnical report noted above and the information will be included in the final TIR. SECTION 3 Off-site Analysis The following is the preliminary Level I downstream analysis. 1ms downstream analysis is based upon the following: • LPD Engineering, PLLC site investigation January 17, 2005 -The site was visited on a partly sunny day which followed a period of nearly 30 consecutive days of record amounts of rainfall. • Meeting with Arneta Heuninger, City of Renton Engineering Specialist, 10126/05 and 11/23/04. • Review of City of Renton as-built records including Pinnacle at the Bluffs Grading and Drainage, Grading and Drainage, as built drawings (1/30/02). • Review of Project topographic survey by SadlerlBarnard. Existing condition The subject property is currently undeveloped. There is an existing abandon building foundation on the site. The site is vegetated with what appears to be second growth with an under story of blackberry and other invasive vegetation. The site is bounded to the east by Interstate Highway 405 right of way, to the north by unimproved SE IlOth St (Morgan St) right of way on the west by Lake Washington Blvd right of way and on the south by a privately owned parcel that is currently being used for vehicle storage and an espresso stand. The existing site slopes up from a low point along Lake Washington Blvd westerly towards the 1405 right of way. The slopes vary from 15% up to 40% and greater (Please note that a protected slope exemption has been granted for this project). The eastern portion of the site has an average slope of 17%. The site is in an Aquifer Protection Zone 2. Developed condition The proposed discharge point for runoff from tbe site is an existing storm drainage CB located in the unimproved Morgan St right of way inunediately north of the proposed development. The path of drainage from there is described as follows (See Figure 4a -Off Site Analysis Drainage System Table, Figure 4b Off- site Drainage Map): • From the Existing type 2 drainage catcbbasin the flow is conveyed west across the Lake Washington Blvd right of way in an approx. 70' 15" PVC pipe. • The 15" pipe outfalls west of the Lake Washington Blvd right of way to a rip rap lined channel that conveys the flow south along the railroad tracks. The channel is armored with 4" to 6" spalls. Channel is approximately 2' -3' wide, 18" deep, with 3:1 side slopes. The channel is approximately 120 If. • Flow in the Channel flows into a 24" CMP culvert which conveys the water west under the railroad tracks, through a catcbbasin, into another 24" CMP pipe to an outfall to "John's Creek". • John's Creek is a stream reach that flows through Coulon Beach Park to discharge into Lake Washington. Existing and Predicted Problems The downstream conveyance system within 'I, mile of the proposed development property is in good condition with no indications of drainage problems observed. OFF·SITE ANALYSIS DRAINAGE SYSTEM TABLE , Surface Water Design Manual, Core Requirement #2 Basin: b Subbasin Name: Subbasin Number: c.t, C</i/i<: ( L1Table.doo 1112/92 .. N "' <£0 o I ,- o , - ~'~:::::::::::::::~~D ;CSC -;;;;r;p;hO;n =============~===~~~~K~~e~nn~~~Y1d~~~;~g ~~r ~~~~C~a~fI~e ; LPD ENGINEERING , eLL e Off-Site Analysis 1-h :l 1936 SEWARD PARK AVENUE s. g l ;s:~:n~LE~~wA~SH~'N~GI~ON:9:8~"~8 ~~ __ ~ ________________________________________ L-________ ~ i!! LH' 206.725.1211 FAX, 106.))5.1211 SECTION 4 Detention and Water Quality Analysis and Design Preliminary drainage drawings are included in Appendix A. Detention As noted in the core requirements section of this report, the project is subject to the negligible increase in peak rate runoff exemption and detention is not required for the project. See the attached preliminary drainage calculations. Water Quality Treatment As noted in the core requirements section of this report, water quality treatment is required to treat the runoff from the impervious areas subject to vehicular use. LPD Engineering wrote a letter to the City of Renton (10/27/06) requesting a drainage requirement adjustment to aliow an alternative method of treatment. A copy of the letter is attached and a summary of the key issues is included below. In coordination with City planners the Owner and Architect have arrived at a preliminary design that sites the building near Lake Washington Blvd. The building location was chosen to minimize the impact to the steep slopes on the eastern portion of the site and to facilitate pedestrian access and enhance the aesthetic of the street. The Architect is proposing a landscaped plaza area with outdoor seating multiple access points to the sidewalk along Lake Washington Blvd. The most feasible location for a biofiltration swale is in the space proposed for the plaza area. Siting the swale here would create restrictions and possibly safety issues for pedestrians in area that intends to encourage pedestrian activity. A prelirninary biofiltration swale design was performed to verify that if required, a swale could be constructed in front of the building. We request an adjustment of the drainage be granted to allow an underground water quality treatment facility in lieu of a biofiltration swale on this site. Options include a wet vault or the Stormwater Managemen~ Inc.'s Stomtfilter treatment system Our preferred method is the Stomtfilter treatment system based on its performance and long term maintenance advantages. Washington State Department of Ecology has approved use of the proposed Stomtfilter Treatment System as a basic stormwater treatment practice for total suspended solids (TSS) removal and King County has approved the System for basic water quality treatment. The proposed Stomtfilter will be maintained by the Owner under a long term maintenance agreement with the manufacturer. A water quality vault would also be maintained by the Owner as required by the City. SECTION 8 TESC Analysis and Design Project plans include a Preliminary Temporary Erosion and Sedimentation Control (TESC) design (See Preliminary Design Documents Appendix A). Included in that design is the TESC measures to be utilized include the following: • Construction Access Pads • Perimeter Siltation Control Measures • Temporary interceptor Swales • Temporary Sediment Pond -Sediment Pond sizing calculations are included in Appendix C. The implementation of the TESC plan and construction maintenance, replacement and upgrading of the TESC facilities sball be the responsibility of the contractor per the contract documents. The TESC facilities will be construction prior to and in conjunction with all clearing and grading activity and is a manner which sediment or sediment laden water does not leave the project site, enter the drainage system or violate applicable water standards. The TESC measures shown on the plan are considered the mininrum requirements for anticipated conditions. During construction the contractor sball be responsible for upgrading these facilities as necessary. APPENDIXA Preliminary Design Documents , ; ! i ! I ! ~ ! i I z "0 -" m ~ ~ o --' N N '" C ~ o E " o C ,,-,=, CeL o u (/) W e-' ~ o "'Z ~ 00 0 1-< ~ >-Z ~ ~~ Ii -0:: ~ u~ j f g, ~ 11 '§ " !\@ ii ( ~ II ~ I J ~i:1 , 1, '·1 ! , ! ! ! i ! / ,I ! i ,/ , '( , , ! ! ! \ , , / , t i J j , / " s.; , d ? / , , r ! " " " / " " '" " I Z-e- I ........ , , ~:. R:'11660.00·~ "-, '","' ~ "-"'-...D:OCT19·IU," _~;:: ,~ , -~, ~ -~ , , '. '" " " ", "-, ", " -''', 20 0 10 20 40 '~~' ! ~ " " " "-\ {l, " "~"" "'" " , "'" 8 "e-"'., ~, ' ' , ~ ~ '~" '/ "'.', \ , " "",00 " '," 0, '" " ~ \ 'c. , ' re91 '" ", '" ' , ... 2.:. (XilO'17"\ _ j .~".<> ". "-', '~\\" 7\, 'OW"", , / " I 0057 " "'" ',-j 0 00'090Cl" ',-'-... ~ ", Scale 1'-20' -, \-'''''''' , L 3OB6" \ '--. '-..., ".... ¥. ~ '""' "-_____ "-\ ___ _ ""'OOOS, \" ,,' " ", '. ,,_, , ___ ,_ '_ !, '\"" ""-' ~ , "'" , 'R '''" , " '" ____ , __ _ !! ""'" '"." ~ , "" ".' '\" -- ",' " ",. '''''''-' , \ ~ ", , ','. \". \' \', ---~\," ~"', ., ,,I,~-- \C7 '" \" """ \i ' ,', '-, , -'%. --" , " '. , \ ''",'" -, \ '\, \ '. I"~, "', _, ' \\ "" ---\, "~~,\, ',,\ '<: -$C", '_', \ .,r!J \ t?,/ \' Surveyor S\DlEFHWi'NMD &: ASSOC. N:. 12714 VALLEY OC E. SUITE B SIJI,INElt "" g8l9O (253) 82&--8135 COHT,I.CT: WICE LUNA Site Benchmark R{R SPIKE SET IN POWER POLf AT SOUTHWEST CORNER Of SITE Ei._SI.60 Legal Description Vertical Datum mY Of REIfTON BENCHIIAA1( '2177 J.5" BRISS IXSK AT "TH£ NW COiHR OF CON:. ~E OF SlGNN.. BRIlGE AT 1HE R/R C!IOSSIm A1 lItE NORTH OOIW«:E OF CClU.0tI PARk EL= J7.~ fEET ~ 88 Basis of Bearing RECORD {f SU1i\{Y IS RECORDED UIf[£R RECORDIHG NUIIBER 9901159OOJ. R[COR(lS or THE kING COlI~ AIJOO"CfI (ROS) NORTH 75 rn OF LOTS 312 THROLCH 315 OF THE PlAT Of r:tl HII..U.1AH's LJ.KE WASHINGTON GAAOCN or EDEN, tMSION NO.5, RECQWED IN VOl.IJI.IE 11, ~ 8J RECORDS OF KING COUNl'(, WASHINGTON. TOGETHfR WITH l}£ SOUTHERIJ 30 FITT OF MORGAN AVE. (TO BE Wu,lED) \ " \ \ ,_4~\., ',,\ '" ~'" \ 1'., .', _'<\ __ , ' \, ,'t:,\ \,,', ',\,I'~~_,,,,, '. __ \,,~ \ '," \'\'. , ""\" , " \ . ',' -'-...", ~\-,.., '\ '\ "-" \.-I ----"t>_ -'--9!r-~ \' ,\\,\, ",'<~\ " "'" \ Q/ C) ;.;\ ~ ~ ." ~ ;;;:, , I"~ " ' , , --\ \\ --:\ • I ~ \ \ ,," ",,", ,', / ,. ~~ --- \ ~ ;\ "'\~'''')( • I i "i> _~,_ \-,' ' ', •. ", ,,-.. \~ \ " \ ~' ;' S. >, (r. , \ , '''' ," .'~, "" " ! -' ,_. .>,.~ ~/ .\ , " " . \ ;,- /~,: \!, \ /.' " 1" ----_ . ..-' - ·k-s_. --.,' / ')/:/ . / \ , \ \ \ \ " \i~>'\\ "'" ~ " , .~ \ \ \ , ~~\,=---.---.:. " ':~.-='-': \ ~ \ " ~,;,=n~:~-':~"--~:;;;~~~!=Cc. ~ -'-,'/ ) >' \ " \ \ \ \ / "-/ :#4 \_-,_.,1 / , , / if' \ , .. \--~ \ \ "-\, \ \ ~\/ /. / ) ~ 'Q ------'--~~ ---- ~~~ ~ p~S~ . _ ftC' _, Ii t A ! r • \ \". 1 ~ . --r-------,-'-- I 'F~.~!J .~7{ f·;5!~ ------'--~ --[X ~--'-"-dk."riiiir \ Checked for Compliance ta City $tandw:d \\ ... 50~ ----~ . ----- . \~~----- li ... ~ " -e---; Lake Washington Blvd ~~' Construction Sequence T. BEfORE ~ CONS1RUCllON M DEVELOPNEIfI AC'rMJY, -. PRECONSffiUCTlOH MEETlNG t.lUST BE HaD BElWEEN 1HE CITY Of RENTON, THE AI'f'I.I:mT AND 1HE N'Pl.Jc.wIS CO"'5'1RlIC"J"O; REPRESENTATh'[. 2. \ofRIfY \£RTIC.I,L Nl) tlORllOlIUL LOCAlJONS OF .IJ.L EXISTING UNDERGROUND ununES. CONTACT AU lfTlJTY CI)I,IPJ,NIES THAT w.Y BE EffEClED EI'I' THE PROPOSED OONSTRUCTKlN. THE 0Nf: CALL NUIoIBER IS 1-1300-424-5555. 3. IIlAINTAIN AI...!. EXlSTNJ tml/lY SERIIICES DURING COHSTRucnoo. VERIFY CRADES PR(JR TO~. f'"l--'G CI.£AR1NG Lt.IllS, 5. INSTALl. STAIIIL1Zfl) CONS1RUC1!ON ENTRANCE. 6, mTAlJ. nrrm FNlRIC FEHC:E: AS tlllIO,ITD ON PlAN 7. INSTAll. 0FfS/J[ ~TCH BASIl PRoTEci1ON 8. CLEAR a: GRUB AREAS OF 111: SIT[ 1ll BE ROJGH GfWlEO Of flUID. 9. CO!€lRIJ:T SEDIMO/T IImRW"lOR SWN.£S AND CHECIC D.+.IIS. 10. IIDIO\'[ Ut/SUrT.I&.E B£ARIHG WiJERW. AS REQIJIRfll 11. GRADE Ah'!l PlACE AlXU'TAIlf FIJ. '5 REc,uRED ANO COMPACT ACCESS DRIVE SUB-GfWlE AS IIOCATED ctj 1HE D~. IHSTAU. S1t:m1 COtM'!'AtICE SYSTOI. DIRECT ill SURfACE WATER TO THE PROf'OS(D CATCH BASIN. t.() I./NCCJIlln.LID SURfACE ~TER S~ BE IUOWED TO l£A\IE THE SITE AT mt DIE DUR!HG TI£ GRAtMNG OPERKIIONS. USE Cl.TCH BASIN SEDlWENT fllITRS TO CAPTURE SEDIWEN'T PRIOR TO ascHAAG[ 12. INSTAll. N£W lJIlJIlES PER THE WIrIIGS . A. WET TN'S TO THE cr.y OF RENTON WATER S'I'STEN StIAU. BE w.oE BY A CITY APf'RO'I{D S~. a THE em OF ROlT(ltj SKAu IISTAU. Tt£ OOMES11C WATER WfJERS. 13. fljlS/1 GRID[ SITE AND CONS1JK.ICT ASPIW.T PAYING AREAS. ACtESS ORMS SlDEWJiKS, CURBS AND c;JJTlERS. 14. COII'UTE STABIlIZATION .. ACaJRlWI! IiTTH lANOSCIPE PLANS . 15. REIOJE EXCiSS EXCAVATED 1MlD!W.S, TRo\SH (lEBR5, AND WASTE: UATEllWS .+.ND DISPOSE Of IN HI AUTHORIZED LOC.I.TION A1 t.W) COST TO M OWNER. 16. CLfAH SlORt.I OIIAINItGE SYSlDI or AI..L SEDIWlI HID DEa'iIS. 17. RD/O'v'[ TDIF'ORAI!Y E~ CONJROL fACIUTIES WHEN sm: IS COiolPlETEl.Y ST,lBUZED. Erosion Control Notes I. BEFORE »1'1 CXWiTRUCTION (JII:EVELOf'I,IOO A::TMTY OCC~, A PRf-CONSTRVCOCW IIEETlHG IoIUST !£ tHO WITH THE CfIY !)<" ~ DEPAIm.!DiT 0'" PU~C '/KIRIG. D£SIG~ E~GINE£~. All. UI,(f!S or CLEARING .'.NO A~Eo\S OF VEGETATION PRESDNATIOU IS PRESCRIBED 011 THE PlAN SHALL BE Cl.£\RLY FlAGGED IN THf FlELC AND OBSEfN[D DURING CDNSTRUC'TK>N. 3. ALL R[QUIREO SEDiIiENTATION"~ROSI~ CONTROL F,lCIl.IT]ES MUST BE CONSTRUCTED .'.NO IN Of'ERATlON PRIOR TO I)NIJ ClfARlNG ~DjOR OTHER COOSTRUCTION TO INSURE TI\I.T sm~ENT w)EN WATER DOES NOT ENiER THE AATURN. IJRAlNAGE SYSTEIi. AU EROSKlN AND SEDII.tENT FACIUTlES SWil BE ),!AlmA/NED IN A SATISfACTORY COtlDl1lON UNTil SUCH TIlliE THAT CLEARING mojOR CONSTRUCTION IS cOl.tPlITED mD POTEIiTW. FOR OH-SITE ffiGS/ON fIAS PASSED. THE Ir.rPLfljENWW, w.rNTHW,lCE, REPlACEUENT AND AOOITIDNS TO £ROSj()NjSEDlIoiENTATI<W CONTROL SYSTEi6 SHAll. B[ "THE RESPCNSIBlliTY or THE PERIITl!E. 04. "THE EROSION oW) SEDIllOOATIlN CONTRa. 5YSTEI.IS D£Pl'TEO ON THIS DRAWING AAf. IKTEHOCD 10 BE IINlMUIi REQIJIREWOOS 10 IftIT Ho'OCIPATED SITE ~ IS CONSJROC"TKlN PROGRESSES oW) U~ OR SE.IS01W. CXlItlIIIOHS OO"ATE, "THE PfR!.IffIII SIIAL.L HffiCIPATE THAJ t.l)RE EROSDH oW) SEDlilfNTAlK:'t1 CCM1!Cl f.-lClJT(S WILL HE NECESSARY TO INSUIE 00II1'l.ETE SIL1A"OON CQIlJR(t ON 11£ PROPOSED SITE. MN> THE COURSE Of ~, IT S/WJ. HE TI£ 0Bl.lGIJ00 AI() ~ Of THE PERM11TII m ,I£l()f!fSS Mrr NEW ~ ffil.T w.y BE CREATED BY HIS ACTMTIS NIO 10 PROIIDE ADOITIOtW. fACll.lJ1(5, OIlER HID ABO'I'E II,"IIUI R[QUIREIoIOOS, AS w.y IJ[ h'E£OED TO PROTECT A£l...W:8oIf PROPERTIES JHI WNER OUIUJY or THE REC£MNG OR.I.I'i'oGE SYSTEII. 5. APPRWAI. or lHS f'lNI IS ~ EROSKlN/SEIlIIOOA~ CONTROL ~Y. IT DOES NOT CONSTITlJIE NI Ii'PRWAL OF S"r0Rl0l DRAtW?E [(SIGN, SIZE hOR I.DCATIOtoI or PIPES, RESTRlCTORS, CKlHNELS, OR R~f~. 6. DlRING THE TIllE P£ROO OF III1vnIBER I THRQ\X;H WrRCH 31. AU PROJECT DmlJRBED SOIL AREAS GREATER "fI-Wj 5,000 SIlUARE FEEf, THIIT ARE TO BE LffT l.IIffIOOI(£D fOR IIORE nWI "!WEl.\IE (12) I{lURS, SIWl. B£ CO'.{RED BY !.IULeii, S()()()I,I,t, DR PlASOC CCJl.'E1i'1NG. 7. IN JoH( KO WHICH HAS 8EEH SfRiPf'EQ Of Y£GflATICIN HlD Wf/ERE NO FURTHER M;)RK IS ANOOPATED FOR A PER100 Of 30 !».YS OR WORE. All IlISIURBED ARfAS IoIUST BE IIIMID!ATELY STABJJ.JmI wrrn I.tIl.CHING, GRASS PI.JHfN> OR OTHER o\."PROYED EROSK»I CONTRa.. TREi\n.ENT APPl.ICABlE TO "THE TIllE Of \'IN! N QI.JESTIOH. GRASS SUOII«; AU»£ WIU.. BE ACCEPrf&E ONLY DlRING THE t.IONTHS Of N'RIl lHRO..IGH SEPIDIBER 1NQUSiV£. SEEDIIIG /MY PROCEED, HCtfEVER, Wl£N&R IT IS N THE INTERESI Of THE PERN1TTrE, BUT IoItIST BE AI.IGI.ENTID \WTH "UlCItNG. NElTING, OR OTHER lREATWENT N'PRO.£D B'!' THE CITY or RfNTOH. OUTSIDE THJ:: SPECIF[!) TillE PERIOD. 8. fOR AU EROSOI,/SEOO£NTA1D1 tcmRO!. PONDS WHERE THE DEIJl STI:)f!N;E DEPTH EXCEEDS 6 INCHES, A FOCE, II WINMUII Of 3 FIEf IIIlH IS REQIIftD, WIIH :3:1 SlOE Sl.CPE.S A"''''.'''' BE Uo:I\Il£' CONSJ"WCTION EHlRANCE, 2-4' X 50' X 8" Dr +-10 6-INCH 0IJN!R't SPN..l.S SIW..L Of IIEH(:UI..AR lNt1iESS HID EGRESS TO THE CONSTRUCTION 511£. VG\l!l1": -..........,."'"-'"~.~-- f~ ",",If~ .f'~'C>"\"':.>' 6~)-"'<'1i~ "IS;, 1 " 1322 Lake fOO1AES pw~-.~ ! / I / / / I / / ( , ( / ; ! / ( ; I ; / I / UDld S81)'I'ln PUD "'0 A.LIJ I I \ ., I I I , \ ,Ql=.L / I I I I I I I ; / . >;. ,~ \0' \ r II • 0 c ,0 " \ : E 0 \ u \ '. :E ~ \. • ~ 0 l\ l' u APPENDIXB Design Calculations and Supporting Information ~Q!mwate~6~ Size and Cost Estimate Kennydale Cafe -Stormwater Treatment System Renton, WA Information provided: • Total contributing area = 0.61 acre • Impervious area = 0.43 acre • Water quality flow, Qwq (60% of 2-yr) = 0.126 cfs • Peak hydraulic flow rate, Qpeak = 0.46 cfs • Presiding agency = City of Renton,WA Assumptions: • Media = ZPG cartridges • Per cartridge flow rate = 15 gpm • Drop required from RIM to outlet = 2.3' minimum Size and cost estimates: The Storm Filter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate associated with the design storm. The water quality flow rate was calculated by using KCRTS and provided to Stormwater360. The StormFilter for this site was sized based on treatment flow rate of 0.126 cfs. To accommodate this treatment flow rate. Stormwater360 recommends using a steel four-cartridge CatchBasin StormFilter (see attached detail). The estimated cost of this size system is $13,900, complete and delivered to the jobsite. The contractor is responsible for setting the CatchBasin Storm Filter and all external plumbing. The steel CatchBasin StormFilter has an internal bypass capacity of 1.0 cfs, which does not exceed the peak flows from this site. The leaders in the storm water industry, Stormwater Managemen~ Inc. and Vortechnics. Inc .. have unN.ed as Stormwater360 n• -the comprehensive provider of stormwater solutions. With an unparalfe/ed product Ifne and unma/c;hed customer support team under one umbrella, Stormwater360 has the treatment option to meet your water quality goals. @Z005 Stormwater360 11/17/2005 lIellgdon www.stormwater360.com 12021-6 NE Airport Way, Portland OR 97220 Toll-free: 800.548.4667 Fax: 800.561.1271 OUTLET STUB (SEE NOTES 405) 10" ~~~~~~_WE~I~R~WTA~LL~~~~~~~--~-L--~~ ____ ~~~ OVE~F G" INLET STUB (OPTIONAL) (SEE NOTE5 405) 4-CARTRIDGE CATCHBASIN -PLAN VIEW INLET GRATE OUTLET STUB REINFORCING BARS (SEE NOTE G) ED ~ Ei~~~~~(5.E.E.N.O.TE~5~4~'~5~)~~~~~~~~~ ...... ~~~~~ 2 1/2" <02005 Stonnwater360 CLEANOUT ACCE55 PLUG ON WEIR WALL 3'-8" 2'-8' 3'-8" 1-----IN5IDE -----I-~INSIDE ---I-----IN5IDE ~~--I 10'-1 " OUTSIDE 4-CARTRIDGE CATCHBASIN -SECTION VIEW CONCRETE COLLAR (SEE NOTE G) 5 TORM FI LTER CARTRI DGE (TYP) (5EE NOTE 2) UNDERDRAIN MANIFOLD THE 5TORMWATER. MANAGEMENT 5tormFII,er® U.s. PATENT No. 5,322,629, No. 5,707,527, No. 10,027,1039 1>.10. b,G49,048, No. 5,1;24,5710, AND OTHER U.5. AND FOREIGN PATEN75 fENDING § STEEL CATCHBASIN STORMFILTER DRAWING ~!.mwater36a ~-=".,..,..,------,_P_LA_N_A.,.-N_D_S_E_CT_IO_N_V_I_EW_S----,. __ ..----,--,,1~, roc STANDARD DETAIL - 4 CARTRIDGE UNIT www.atonnlljafllr38G,com DATE: 11101105 SCALE: NONE FILE NAME: CBSF4-S-DTl DRAWN: MJW CHECKED: ARG C200S Stormwat<r360 PER.MANE~' POOL ELEVATION VARIES 2'-3 5/B" MAX. ~[- INLET STUB 7 (OPTIONAL) (5EE NOTE5 4;' 5) 2' IN51DE 2'-0 1/2" f--OUTSIDE-I OUTLET 5TUB (5EE NOTE5 4;' 5) 2"0 OUTLET PIPE FROM UNDERDRAIN 4-CARTRIDGE CATCHBASIN -SECTION VIEW 3'-9' 1'-';" CAR,RIDGE 5UPcORT (TYP) L--__ '-__ ...J ...1 LlPTING EYE (TYP OF 4) ELEVATION 4-CARTRIDGE CATCHBASIN -SECTION VIEW THE 5TORMWATER MANAGEMENT StormF'lter® U.S. PATENT No. 5,322,G29, No. 5,707,527, No, G,027,G39 No. G,G49,048, No. 5,G24,57G, AND OTHER U.s. AND FOREIGN PATENTS FENDING ~.!.mwate~§) STEEL CATCHBASIN STORMFIL TER SECTION VIEWS STANDARD DETAIL - 4 CARTRIDGE UNIT DRAWING 2 www.Atoi •• lW.ter3lO.com ~~~~~~~~ __ -,~~~~~~ ______ -,~~~~~~~m~ DATE: 111{11105 SCALE: NONE FILE NAME: CBSF4-S-DTL DRAWN: MJW CHECKED: ARG GENERAL NOTES I) STORM FILTER BY STORMWATER3GO; WEST, PORTLAND, OREGON (800) 548-4GG7; EAST, 5CARBOROUGH, ME (877) 907-8G7G; MID-ATLANTIC ELKRIDGE, MD (8GG) 740-3318. 2) FILTERS TO BE 51 PHON-ACTUATED AND 5ELF-CLEANING. 3) 5TEEL 5TRUCTURE TO BE MANUFACTURED OF ! /4 INCH STEEL PLATE. 4) 5TORMFILTER REQUIRES 2.3 FEET OF DROP FROM RIM TO OUTLET. INLET 5HOULD NOT BE LOWER THAN OUTLET. INLET (IF APPLICABLE) AND OUTLET PIPING TO BE SPECIFIED BY ENGINEER AND PROVIDED BY CONTRACTOR. 5) CBSF EQUIPPED WITH 4 INCH (APPROXIMATE) LONG STUBS FOR INLET (IF APPLICABLE) AND OUTLET PIPING. STANDARD OUTLET STUB 15 8 INCHES IN DIAMETER. MAXIMUM OUTLET STUB IS 15 INCHE5 IN DIAMETER. CONNECTION TO COLLECTION PIPING CAN BE MADE USING FLEXIBLE COUPLING BY CONTRACTOR. G) FOR H-20 LOAD RATING, CONCRETE COLLAR IS REQUIRED. CONCRETE COLLAR WITH QUANTITY (2) #4 REINFORCING BARS TO BE PROVIDED BY CONTRACTOR. 7) ALL 5TORMFILTERS REQUIRE REGULAR MAINTENANCE. REFER TO OPERATION AND MAINTENANCE GUIDElINES FOR MORE INFORMATION. 4-CARTRI DGE CATCHBASI N STORMFILTER DATA STRUCTURE I D XXX WATER QUALITY FLOW RATE (ds) XXX PEAK FLOW RATE « I ds) XXX RETURN PERIOD OF PEAK FLOW ( cs) XXX CARTRIDGE FLOW RATE ( I 5 OR 7.5 qpm) XX MEDIA TYPE (CSF, PERLITE, ZPG) XXXXX RIM ELEVATION XXX.XX' PIPE DATA, I.E. DIAMETER INLET STUB XXX.XX' XX" OUTLET STUB XXX.XX' XX" CONFIGURATION OUTLET 1001:1001 INLET SLOPED LID YE5INO SOLID COVER YES\NO NOTES/SPECIAL REQUIREMENTS, ACCESS COVE~ --... (TYP) '\ ~ INLET GRATE 02005 Stonnwab:r360 """"f.~-''-'.''''''''''\'--'' .•••• :7";...-. ; .. -'-•. ' .~, ___ --./-... -.-::,-,-;.,-.... -"-'."--'-•• ·A~· -T'---;;-. ~-.--'-"---~.-~:'-'. '.-"--'" "0' .'--"';" ".' .. '\ . ~ .. ~'mX'" <~' ..• "';;:"""',:.,+-. I:::.~: I II~"~, INsf] I:~IM II~ .' .. ' I ~· .".' : .... ;.-........ : .. < ... : ..... ,. ,..". ,. . ,'. , : .... '.'; -' :.. .' .:. '. . '~':. • .... ..., .. '.~,;" /'';; '~;" .... < •.. ~ .. '.- 4' INSIDE RJM 2'-4" INSIDE RIM 10'-5" OUTSIDE RIM 4' INSIDE RIM 4-CARTRIDGE CATCHBASIN -TOP VIEW THE 5TORMWATER MANAGEMENT StormFllter® U.s. PA.TENT No. 5,322,G2~, No. 5.707,527. No. b.027,G3~ No. ':;,1049,045, No. 5,1024,5710, AND OTHER U.s. AND FOREIGN PATENTS PENDING §) STEEL CATCHBASIN STORMFIL TER DRAWING gpLmwater360 TOP VIEW, NOTES AND DATA ,3" STANDARD DETAIL - 4 CARTRIDGE UNIT ~D~A=TE~,,~,ro~,-ro~5'1~:s~CA~L~E'~N=ON~E------~IF=IL~E~~-M-E-'C-B=SF~"'=-=DR~--------O=IIDAA--W-N-'M-Jw--I~c-H=EC=K~ED~'A~R~G~ www.storlnWlltw38O.com , --._-'----------------------- ------------ (j,'f.,1 d J(t~..fV/l ~ IJI'//<-~I I 4 (1 10 /::-{ s vJ,/) yvz I 1 ih~( .. k -g 7 lr~ il,6! Av- 4; ~ tJ,18 Av- If/ = tJ I 4-3 lTu - 15 Jr/ Ih I ,0(/ ?'l/l d wl ~ U1' r v ---'--_--l-~~~-=-----'--=------"--.J---'--"'-----------------'------------____+~ ----- I ~'-0"'1---"1:..-- Il-r ; iiI' / tJ, (/ I /l-r.-- ,4 f .;:: tI ~r'F'~J-. I) ! {l:/ {/c:: fJE ~ (;L;~ - "-f;,o I S~ 00% (j~/) lor; J <) ?-/ b l--r .66--=(IOS-('O ) -=---f-r;' 5:::0-v10 (5 t.. ~(((/zJ tel"? r,) r! t:-Vi I) /(/ () j) 3{;o ;!J;/c; LF e ~~ [,070 Lj::::: ,j' J, ~ 1/ " .. «'/ f/,,/ ::!. -/37- 1/ I -l-----------, i Cd /1£, {j?'/~ ,c,l:;i> I I I 11/16/05 4 :41 :45 pm Preliminary Storm Drainage LPD Engineering, PLLC Coughlin, Porter, Lundeen Inc. Kennydale Cafe Calcs page 1 ===================================================================== BASIN ID: 100yrdev SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TyPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet L: TcReach -Channel L: PEAK RATE: 0.46 cfs BASIN ID: 100yrex SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TyPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet L: TcReach -Shallow L: PEAK RATE: 0.38 cfs BASIN ID: 10yrdev SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TyPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet L: TcReach -Channel L: PEAK RATE: 0.33 cfs BASIN SUMMARY k./ NAME: Kennydale cafe -eJ(il!i~ilig 0.61 Acres TYPE1A 3.90 inches 10.00 min BASEFLOWS: AREA .. : CN .... : TC .... : 0.00 cfs PERV 0.18 Acres 89.00 5.37 min 0.20 100.00 350.00 VOL: ns:0.2400 p2yr: 2.00 kC:42.00 s:0.1300 0.17 Ac-ft TIME: s:0.5000 480 min NAME: Kennydale cafe -existing 0.61 Acres BASEFLOWS: 0.00 cfs TYPE1A PERV 3.90 inches AREA .. : 0.61 Acres 10.00 0.20 100.00 215.00 VOL: min CN .... : 89.00 TC .... : 5.96 min ns:0.2400 p2yr: 2.00 kS:8.00 s:0.2100 0.14 Ac-ft TIME: s:0.5000 480 min de...-- NAME: Kennydale cafe -exi:!!~i1I9 0.61 Acres BASEFLOWS: 0.00 cfs TYPE1A PERV 2.90 inches AREA .. : 0.18 Acres 10.00 0.20 100.00 350.00 VOL: min CN .... : 89.00 TC .... : 5.37 min ns:0.2400 p2yr: 2.00 kc:42.00 s:0.1300 0.12 Ac-ft TIME: s:0.5000 480 min IMP 0.43 Acres 98.00 5.36 min IMP 0.00 Acres 0.00 0.00 min IMP 0.43 Acres 98.00 5.36 min 11/16/05 4 :41 :45 pm Preliminary Storm Drainage LPD Engineering, PLLC Coughlin, Kennydale Calcs Porter, Cafe Lundeen Inc. page 2 ===================================================================== BASIN ID: 10yrex SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TyPE .... : PRECIPITATION .... : TIME INTERVAL .... : BASIN SUMMARY NAME: Kennydale cafe -existing 0.61 Acres BASEFLOWS: 0.00 cfs TYPEIA PERV 2.90 inches AREA .. : 0.61 Acres 10.00 min CN .... : 89.00 TC .... : 5.96 min ABSTRACTION COEFF: 0.20 TcReach -Sheet L: 100.00 TcReach -Shallow L: 215.00 PEAK RATE: 0.25 cfs VOL: s:0.5000 ns:0.2400 p2yr: 2.00 ks:8.00 s:0.2100 0.09 Ac-ft TIME: 480 min de./' eKistipg BASIN ID: 25yrdev SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TYPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet TcReach -Channel PEAK RATE: 0.40 BAS IN ID: 25yrex SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TYPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: NAME: Kennydale cafe - 0.61 Acres TYPEIA 3.40 inches 10.00 min BASEFLOWS: AREA .. : CN .... : TC .... : 0.00 cfs PERV 0.18 Acres 89.00 5.37 min 0.20 L: 100.00 L: 350.00 cfs VOL: ns:0.2400 p2yr: 2.00 kc:42.00 s:0.1300 0.15 Ac-ft TIME: s:0.5000 480 min NAME: Kennydale cafe -existing 0.61 Acres BASEFLOWS: 0.00 cfs TYPE1A PERV 3.40 inches AREA .. : 0.61 Acres 10.00 min CN .... : 89.00 TC .... : 5.96 min TcReach -Sheet L: 0.20 100.00 215.00 ns:0.2400 p2yr: 2.00 ks:8.00 s:0.2100 0.12 Ac-ft TIME: s:0.5000 TcReach -Shallow L: PEAK RATE: 0.32 cfs VOL: 480 min IMP 0.00 Acres 0.00 0.00 min IMP 0.43 Acres 98.00 5.36 min IMP 0.00 Acres 0.00 0.00 min 11/16/05 4:41:45 pm Preliminary Storm Drainage LPD Engineering, PLLC Coughlin, Kennydale Calcs Porter, Lundeen Inc. Cafe page 3 ===================================================================== BASIN ID: 2yrdev SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TyPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet L: TcReach -Channel L: PEAK RATE: 0.21 cfs BASIN ID: 2yrex SBUH METHODOLOGY TOTAL AREA ....... : RAINFALL TYPE .... : PRECIPITATION .... : TIME INTERVAL .... : ABSTRACTION COEFF: TcReach -Sheet L: TcReach -Shallow L: PEAK RATE: 0.14 cfs BASIN SUMMARY NAME: Kennydale cafe - 0.61 Acres TYPE1A 2.00 inches 10.00 mln BASEFLOWS: AREA .. : CN .... : TC .... : d-e ./ e7:iSLiIIg 0.00 cfs PERV 0.18 Acres 89.00 5.37 min 0.20 100.00 350.00 VOL: ns:0.2400 p2yr: 2.00 kC:42.00 s:0.1300 0.08 Ac-ft TIME: s:0.5000 480 min NAME: Kennydale cafe -existing 0.61 Acres BASEFLOWS: 0.00 cfs TYPE1A PERV 2.00 inches AREA .. : 0.61 Acres 10.00 min CN .... : 89.00 TC .... : 5.96 min 0.20 100.00 215.00 ns:O.2400 p2yr: 2.00 ks:8.00 s:0.2100 0.05 Ac-ft TIME: s:0.5000 VOL: 480 min 117 i-.) IMP 0.43 Acres 98.00 5.36 min IMP 0.00 Acres 0.00 0.00 min Page I of I Proposed Areas Date: 11-15-2005 Time:11:13:13a . ··QIUrlj~ Layer Description impervious vehicle-use Asphalt Pavement . . lIllpervlous Building Basin Area: 26562 Sf (.61 Ac) Pervious Area: 7883 Sf (.18 Ac) [29.68%] Impervious Area: 18679 Sf (.43 Ac) [70.32%] Layer Description Layer Block Quantity Imp DeJ?th Area Sf(Ac) Volume Volume (sq.m.) (cu. ft.) (cu.yd.) Yes 6 11938(.3) 5969.1 221.1 Yes I 6740(.2) 561.7 20.8 Length (ft.) Description Drawing performed on:Z:\LPD Engineering PLLCIProjects\Pool Brothers ConstructionlKennydale Cafe Lake Washington CommerciallDesign IAreas\Lake _ Base.dwg By:Leland Note: All information calculated from objects in drawing. Drawing must be draw accurately for information to be reliable. file:IIZ:\LPD Engineering PLLClProjectslPool Brothers ConstructionlKennydale Cafe La... 1111512005 .e :0 ;0 Permeability is moderatelY rapid in the surface layer ,and subsoil ·and very slow in the substratum. Roots penetrate easily to the consolidated substra- tum. where they tend to mat on the surface. Some roots enter the substratum through cracks. Water moves on top of the substratum in winter. Available water capacity is low. Runoff is slow to medium~ and the hazard of erosion is moderate. This soil is used for timber, pasture, berries, and row crops, and for urban development. Capability unit IVe-2; woodland group 3d!. Alderwood gravelly sandy loam, 0 to 6 percent slopes (AgB).--This soil is nearly level and undulating. It is similar to Alderwood gravelly sandy loam, 6 to 15 percent Slopes, but in places its surface layer is 2 to 3 inches thicker. Areas are irregular in shape and range from 10 acres to slightly more than 600 acres in size. Some areas are as much as IS percent included Norma, Bellingham, Tukwila, and Shalcar soils, all of which are poorly drained; and some areas in the Vicinity of Enumclaw are as much as 10 percent Buckley soils. Runoff is slow, and the erosion hazard is slight. This Alderwood soil is used for timber. pasture, berries, and row crops, and for urban development. Capability unit IVe-2; woodland group 3d2. Alderwood avelly sandy loam, 15 to 30 ercent slopes (AgD) .--Depth to the su stratum in this 5011 varies within short distances, but is commonly about 40 inches. Areas are elongated and range from 7 to about 250 acres in size. Soils included with this soil in mapping make up no more than 30 percent of the total acreage. Some areas are up to 25 percent Everett soils that have slopes of 15 to 30 percent, and some areas are up to 2 percent Bellingham, Norma, and Seattle soils, which are in depressions. Some areas, especially on Squak Mountain, in Newcastle Hills, and north of Tiger Mountain, are 25 percent Beausite and OVall soils. Beausite soils are underlain by sandstone, and Ovall soils by andesite. " Runoff is medium, and the erosion hazard is severe. The slippage potential is moderate. This Alderwood soil is used mostly for timber. Some areas on the lower parts of slopes are used for pasture. Capability unit VIe-2; woodland group 7 ----- Alderwood and Kitsa~ soils~ very steep (AkF).-- This mapping unit is a out 50 percent Alderwood gravelly sandy loam and 25 percent Kitsap silt loam. Slopes are 25 to 70 percent. Distribution of the soils varies greatly within short distances. About 15 percent of some mapped areas is an included, unnamed, very deep, moderately coarse textured soil; and about 10 percent of some areas is a very deep, coarse-textured Indianola soil. Drai1l8.ge' and pomeability vary. Runoff is rap to-YerJ"""rapid; and the erosion hazard is severe a very severe. The slippage potential These soils are used for timber. unit VIle-I; woodland group 2dl. 10 Arents~ Alderwood Material Arents, Alderwood material cons ists of Ale soils that have been so disturbed through uri ization that they no longer can be classifiet the Alderwood series. These soils, however, many similar features. The upper part of thl to a depth of 20 to 40 inches, is brown to d brown gravelly sandy loam. Below this is a brown, consolidated and impervious substratw Slopes generally range from 0 to 15 percent. These soils are used for urban developrnen Arents, Alderwood material, 0 to 6 perc en (AmB). -In many areas this soil is level~ as result of shaping during construction for ur facilities. Areas are rectangular in shape range from 5 acres to about 400 acres in siz Representative profile of Arents, Alderwo material, a to 6 percent slopes, in an urban 1,300 feet west and 350 feet south of the no corner of sec. 23, T. 25 N.) R. 5 E.: o to 26 inches, dark-brown (lOYR 4/3) gravel sandy loam, pale brown (lOYR 6/3) dry; massive; slightly hard, very friable, sticky, nonplastic; many roots; mediun abrupt, smooth boundary. 23 to 29 inc thi ck. 26 to 60 inches, grayish-brown (2.5Y 5/2) lH conSOlidated to strongly consolidated till, light brownish gray (2.5Y 6/2) , common, medium, prominent mottles of ~ bro\m (lOYR 5/6) moist; massive; no r( medium acid. Many feet thick. The upper, very friable part of the soil to a depth of 20 to 40 inches and ranges frc grayish brown to dark yellowish brown. Some areas are up to 30 percent included that are similar to this soil material, but shallower,or deeper over the compact substr and some areas are 5 to 10 percent very gra Everett soils and sandy Indianola soils. This Arents, Alderwood soil is moderatel drained. Permeability in the upper, distur material is moderately rapid to moderately depending on its compaction during construe The substratum is very slowly permeable. R penetrate to and tend to mat on the surface consolidated substratum. Some roots enter substratum through cracks. Water moves on ~he substratum i~ winter. Available water 15 low. Runoff IS slow, and the erosion ha Slight. This soil is used for urban development. pability unit IVe-2; woodland group 3d2. Arents, Alderwood material, 6 to IS perc slopes (AmC).--This soil has convex slopes. are rectangUlar in shape and range from 10 about 450 acres in size. October 27, 2005 City of Renton PlanninglBuilding/Public Works 1055 S Grady Way Renton, W A 98055 Attention: Arneta Henninger Re: Kennydale CaJtf 1322 Lake Washington Blvd Dear Arneta: LPD Engineering, PLLC This letter is to follow-up our conversation yesterday regarding the stonn water quality treatment for the proposed commercial development at 1322 Lake Washington Blvd in Renton. Attached is a preliminary site layout sketch. Existing site The existing site slopes up from a low point along Lake Washington Blvd westerly towards the 1405 right of way. The slopes vary from 15% up to 40% and greater (Please note that a protected slope exemption has been granted for this project). The eastern portion of the site has an average slope of 17%. The site is in an Aquifer Protection Zone 2. Proposed development The proposed development will be a 3 story mixed use building with associated parking. Given the topography of the existing site, a number of structural retaining walls will be included in the proposed design. To minimize the impact to the steeper portion of the site to the west, proposed improvements are located to the east as much as possible. The building has been sited fronting the street as encouraged by land use to facilitate pedestrian access and enhance the aesthetic of the street. Storm drainage Per on our conversation, I understand that the proposed stonn drainage design shall be required to meet requirements ofthe 1990 King County Surface Water Design Manual (KCSWDM). Based on these requirements it appears that the project will be required to provide basic water quality treatment for the runoff from impervious areas subject to vehicular use (over 5,000 sf proposed). Per KCSWDM and City of Renton Code it appears that the only approved method of basic water quality treatment is a biofiltration swale. We request an adjustment of the drainage be granted to allow use ofthe Stonnwater Management, Inc.'s Stonnfilter treatment system in lieu of a biofiltration swale on this site. Although a biofiltration swale could be sited in the landscaped area between the proposed building and the right of way, on the downstream portion of the site, we believe the use of a Stonnfilter would result in a superior design due to the following: I. The only practical spot for a biofiltration swale given the site topography is on the eastern end of the site adjacent to the Lake Washington Blvd. right of way. A proposed swale would have to be located parallel to the sidewalk along the property frontage. The slope along the sidewalk here is approximately 5% which is typically too steep for a biofiltration swale. The swale will require grading some steep slopes, possibly retaining walls or rockeries LPD Engineering 7936 Seward Park Avenue South, Seattle, Washington 98118 Phone/Fax: (206) 725-1211 which could create restrictions or safety issues for pedestrians in the area that we are trying to encourage pedestrian activity. 2. The use of an underground stormwater quality treatment facility will allow the full width of the buffer between the right of way and the building to be landscaped, which could provide an enhancement to the community and the aesthetic of the building. 3. Water quality treatment -Washington State Department of Ecology has approved use of the proposed Stormfilter Treatment System as a basic stormwater treatment practice for total suspended solids (TSS) removal (please see the attached Ecology memorandum, or refer to the following link: http://www . ecy. wa. gov/programs/wq/ stormwa lcr/newtechluse designations/stormfilter guld.pdf Our proposed design would be in accordance with Ecologies requirements. Attached is a sketch of the preliminary site layout. Please consider the information outlined above and let us know if the City of Renton will consider the use of a Stormwater Management Inc.' s Stormfilter Treatement System in lieu of a biofiltration swale for basic water quality treatment. Please let me know if you need further information or if you have any questions. Thank you for your consideration of our request n , ~tne ng, PLLC Jeff Lamoureux PE LPD Engineering 7936 Seward Park Avenue South, Seattle, Washington 98118 Phone/Fax: (206) 725-1211 Geotechnical Engineering Water Resources Environmental Assessments and Remediation Sustainable Development Services Geologic Assessments Associated Earth Sciences, Inc. CtJ~'f'trt7'!f:if ~t'll'f q/JeIWC6' Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report KENNYDALE CAFE Renton, Washington Prepared for Pool Brothers Construction, LLC/ HearthStone Homes, LLC Project No. KE04520A February 27,2006 Associated Earth Sciences, Inc. February 27, 2006 Project No. KE04520A iliw~~~ eetehrafil1J 251jears o(.S'ervice Pool Brothers Construction, LLC/HearthStone Homes, LLC P.O. Box 3023 Renton, Washington 98056 Attention: Mr. Matt Pool Subject: Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Kennydale Cafe 1322 Lake Washington Boulevard North Renton, Washington Dear Mr. Pool: We are pleased to present the enclosed copies of the above-referenced report. This report summarizes the results of our subsurface exploration, geologic hazard, and preliminary geotechnical engineering studies and offers recommendations for the preliminary design and development of the proposed project. Our recommendations are preliminary in that building plans/construction details have not yet been finalized. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. If you should have any questions or if we can be of additional help to you, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington ~!HA" Kurt D. Merriman, P.E. Principal Engineer KDMIJi./ KE04520A2 Projecls\20040520\KE\WP Kirldand Office· 911 FdihAvenue, Suite 100· Kirkland, WA 98033· P 1(425) 827-7701. F I (425) 827-5424 Everen Office· 2911 1/2 HewinAvenue, Suite 2· Lvemt, WA 98201 • P 1(425) 259-0522· F 1(425) 252-3408 \v\v\,\;ac.sgeo,cofll SUBSURFACE EXPLORATION, GEOLOGIC HAZARD, AND PRELIMINARY GEOTECHNICAL ENGINEERING REPORT KENNYDALE CAFE Renton, Washington Prepared for: Pool Brothers Construction, LLCI HearthStone Homes, LLC P.O. Box 3023 Renton, Washington 98056 Prepared by: Associated Earth Sciences, Inc. 911 5th Avenue, Suite 100 Kirkland, Washington 98033 425-827-7701 Fax: 425-827-5424 February 27, 2006 Project No. KE04520A Kennydale Cafe Renton, Washington 1.0 INTRODUCTION Subsuiface Exploration. Geologic Hazard, and Preliminary Geotechnical Engineering Repon Project and Site Conditions I. PROJECT AND SITE CONDITIONS This report presents the results of our subsurface exploration, geologic hazard, and preliminary geotechnical engineering study for the proposed Kennydale Cafe to be located at 1322 Lake Washington Boulevard North in Renton, Washington. Our recommendations are preliminary in that building plans/construction details have not yet been finalized. The approximate location of the subject site is shown on the Vicinity Map, Figure 1. The property boundaries and the locations of the explorations conducted at the site, as well as other pertinent site features, are shown on the Site and Exploration Plan, Figure 2. In the event that any changes in the nature, design, or locations of the structures are planned, the conclusions and recommendations contained in this report should be reviewed and modified, or verified, as necessary. 1.1 Purpose and Scope The purpose of this study was to provide subsurface data to be used in the preliminary design and development of the above-mentioned project. Initial site exploration was conducted during the month of September 2004 and consisted of excavation of five exploration pits within the central portion of the site. Our current study, as outlined in our February 6, 2006 proposal, included a review of available geologic literature, drilling of two exploration borings, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow ground water conditions. Data obtained during our September 2004 exploration is used as a part of this report. Geotechnical engineering studies were also conducted to assess the types of suitable foundations, allowable foundation soil bearing pressures, anticipated settlements, basement/retaining wall lateral pressures, floor support recommendations, and drainage considerations. This report summarizes our previous and current fieldwork and offers preliminary development recommendations based on our present understanding of the project. I. 2 Authorization Verbal authorization to proceed with this study was granted by Mr. Matt Pool of Pool Brothers Construction, LLC/HearthStone Homes, LLC. Our recent study was accomplished in general accordance with our scope of work dated February 6, 2006. This report has been prepared for the exclusive use of Pool Brothers Construction, LLC/HearthStone Homes, LLC and their agents for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTIld, KE04520A2 -Projecrsl20040520lKEIWP Page 1 Kermydale Cafe Renton, Washington 2,0 SITE AND PROJECT DESCRIPTION 2.1 Site Description Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Project and Site Conditions The subject site is located at 1322 Lake Washington Boulevard North in Renton, Washington. The site is currently vacant; however, based on the existence of concrete basement walls and charred remains of wood flooring and walls within the western portion of the site, it appears that the site has previously been occupied. The site is bounded on the north by vacant land, on the south by a vehicle storage yard, on the east by Interstate 405 (1-405), and on the west by Lake Washington Boulevard North. The site ascends toward the east from the western property line. Slope gradients range from approximately 15 percent within the western portion of the site to in excess of 40 percent within the eastern portion of the site. Overall topographic relief across the site is on the order of 100 feet. Midway up the slope within the central portion of the site, what appears to be an unimproved path or roadway extending in a northeasterly direction across the slope face was observed. No information regarding construction of this feature was available to us, but it appears as if it may have been created by north-south excavation across the slope face. The area is now partially overgrown with blackberry vines and deciduous trees. Vegetation within the western portion of the site in the vicinity of the previously existing structure consists of blackberry vines. A single pine tree exists adjacent to the southwest corner of the remaining foundation. Vegetation across the central and eastern portions of the site consists of a moderate coverage of deciduous trees with brush and blackberry vines comprising much of the understory. 2.2 Proposed Construction It is our understanding that project plans include construction of a four-unit townhouse above a 3,200 square foot restaurant. The lower-level, daylight restaurant will be excavated into the existing hillside above Lake Washington Boulevard North. Based on Sheet A8 "Elevations" and on Sheet A9 "Details" dated January 6, 2006 by Rick Anderson, Architect, a split-level parking lot is to be created upslope from the proposed structure. Access to the parking area will be via a paved driveway extending upslope from Lake Washington Boulevard North along the south side of the proposed structure. The western (lower) portion of the parking lot is at an elevation approximately 10 feet above Lake Washington Boulevard North. The eastern (upper) portion of the parking lot is at an elevation approximately 30 feet above adjacent Lake Washington Boulevard North. A four-car garage is to be built within the northeast portion of the upper parking lot. Retaining walls to a height of 15 feet are anticipated. February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTIJd -KE04520A2 -ProjectsI20040520IKEIWP Page 2 Kennydale Caje Renton, Washington 3.0 SUBSURFACE EXPLORATION Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report ProjeCi and Site Conditions Previous site exploration consisted of excavation of five exploration pits during the month of September 2004 to evaluate near-surface conditions within the "roadway" feature within the central portion of the site. The exploration pit logs are resubmitted as a part of this report. Current exploration consisted of advancement of two exploration borings; one within the lower portion of the site and one midway upslope in the vicinity of the proposed cut for the eastern parking lot wall. The various types of sediments, as well as the depths where the characteristics of the sediments changed, are indicated on the exploration logs presented in the Appendix. It should be noted that the depths indicated on the attached logs where conditions changed may represent gradational variations between sediment types in the field. Our explorations were located in the field relative to topographic information provided to us. The approximate locations of the explorations are shown on the Site and Exploration Plan, Figure 2. The conclusions and recommendations presented in this report are based, in part, on the exploration pits excavated during our earlier (September 2004) exploration and on our current borings. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. 3.1 Exploration Pits The exploration pits completed during September 2004 were excavated with a track-mounted excavator provided for our use. The exploration pits permitted direct, visual observation of subsurface conditions. Materials encountered in the exploration pits were studied and classified in the field by a geotechnical engineer from our firm. All exploration pits were backfilled immediately after examination and logging. Selected samples were then transported to our laboratory for further visual classification and testing, as necessary. The exploracion logs presented in the Appendix are based on [he field logs and inspection of the samples secured. 3.2 Exploration Borings The exploration borings were completed by advancing a hollow-stem auger with a portable drill rig subcontracted to us. During the drilling process, samples were obtained at 2.5-to 5- foot-depth intervals. The borings were continuously observed and logged by a geotechnical engineer from our firm. The exploration logs presented in the Appendix are based on the field logs, drilling action, and inspection of the samples secured. February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld -KE04520A2 -Projects12004()5201KE1WP Page 3 Kennydale Caje Renton, Washington Subsuiface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Project and Site Conditions Disturbed, but representative samples were obtained by using the Standard Penetration Test (SPT) procedure in accordance with American Society for Testing and Materials (ASTM):D 1586. This test and sampling method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance ("N") or blow count. If a total of 50 blows are recorded within one 6- inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N -value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached boring logs. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing, as necessary. 4.0 SUBSURFACE CONDITIONS Review of the regional geologic map entitled Draft Geologic Map of King County, Washington by Derek Booth, Ralph Haugerud, and Jill Sacket (December 27, 2002) indicates that the area of the subject site is underlain by pre-Fraser deposit soil. Our interpretation of the sediments encountered in our exploration pits and borings is in general agreement with the regional geologic map. Subsurface conditions at the project site were inferred from the field explorations accomplished for this study. Additional regional geologic information was provided through review of applicable geologic literature. As shown on the attached exploration logs, sediments encountered in our exploration pits and borings generally consisted of pre-Fraser deposits overlain by topsoil/disturbed soil. The following section presents more detailed subsurface information organized from the youngest to the oldest sediment types. 4.1 Stratigraphy Topsoil/Disturbed Soil A surficial layer of topsoil/disturbed soil was encountered in the explorations at the site. This surficial soil consisted generally of a brown to dark brown mixture of silt and sand in a loose condition. The topsoil/disturbed soil layer ranged in thickness from approximately 1 to 5 feet. Due to the low density observed, the existing topsoil/disturbed soil layer is not considered suitable in its existing condition for foundation or pavement support. Based on site grades shown on the project plans provided to us, these materials will be removed from within the building areas as part of site grading and excavation activity. February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld -KE04520A2 -Projeclsl20040520lKEI WP Page 4 Kennydale Cafe Remon, Washington Pre-Fraser Deposits Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Project and Site Conditions Beneath the surficial soil, sediments consisting of weakly to moderately oxidized silts and fine to coarse sand with faint to prominent laminations were encountered. These sediments are interpreted to be pre-Fraser deposits. Based on the relatively fine-grained nature of the soils encountered, these soils were likely deposited in a low-energy environment, such as a lake, and are therefore referred to as lacustrine deposits. The upper, approximately 2 to 3 feet of these deposits were observed to be in a weathered, relatively loose condition, not considered to be suitable for foundation or pavement support without recommended remedial densification, as described herein. Below the weathered zone, the lacustrine deposits were observed to be in a dense to very dense condition and are considered suitable for support of foundation loads and pavement support with proper preparation. Lacustrine deposits are composed primarily of silt and fine sand, considered highly moisture-sensitive, and are highly prone to disturbance when wet site or weather conditions exist. Vigilance will be required when foundation bearing soils composed of lacustrine deposits are exposed to prevent disturbance and resulting increased costs for removing the disturbed soils and restoring suitable support conditions. 4.2 Hydrology No ground water seepage was encountered during our September 2004 exploration. Lenses of very moist to wet soil were encountered below a depth of approximately 5 feet in both exploration borings advanced during our February 2006 exploration. This is consistent with a type of ground water seepage known as interflow. Interflow consists of surface water that infiltrates through relatively permeable soils and becomes trapped or perched atop underlying, low-permeability surfaces or layers. Perched zones of ground water may also occur within pre-Fraser deposit soil in areas where these sediments exhibit increases in permeability due to localized grain size variations. Ground water measured within exploration borings EB-I and EB-2 after completion of drilling was encountered at a depth of 18 feet below lowest adjacent ground surface. No monitoring wells were installed during our current exploration program. It should be noted that the occurrence and level of ground water seepage at the site may vary in response to changes in season, precipitation, irrigation, and other factors. Perched and interflow seepage should be expected during the wetter winter and spring months and following periods of heavy or sustained precipitation. February 27, 2006 ASSOCIATED EARm SCIENCES, INC. MT/ld " KE0452DA2 -Projects\20040520IKE\ WP Page 5 Kennydale Caje Renton, Washington Subsurface ExploraJion, Geologic Hazard, and Preliminary Geotechnical Engineering Repon Geologic Hazards and Mitigations II. GEOLOGIC HAZARDS AND MITIGATIONS Based on information obtained from the City of Renton's web site http://rentonnet.org/MapGuide/maps/ParceLmwf , the project is in an area of mapped erosion hazards, moderate landslide hazards, and regulated slopes ranging from 15 to < 90 percent. The hazards and regulated slopes are discussed in the following sections and recommended mitigation measures presented in conformance with the Renton Critical Areas Ordinance No. 5137. The following discussion of potential geologic hazards is based on the geologic, slope, and shallow ground water conditions as observed and discussed herein. 5.0 LANDSLIDE HAZARDS AND RECOMMENDED MITIGATION Observation of site slopes revealed no evidence of instability or past landslide activity. Unweathered, dense to very dense soil underlying the surficial stratum at the site is not considered likely to be mobilized due to relatively high strength related to density. Based on site observation, it is our opinion that the soils (to a depth of approximately 2 to 8 feet) across the surface of the site slopes possess a moderate potential for shallow slumps. The risk of shallow soil movement within the surficial soil increases substantially following extended periods of wet weather or during moderate to large seismic events. The potential for shallow surficial slope instability will be reduced by proper site drainage, retaining wall construction, impact wall construction, and placement of a debris fence along the top of the impact wall, as discussed later in this report. In our opinion, the proposed development will not adversely affect existing site hazards. The proposed improvements may eliminate or stabilize some of the landslide hazard and steep slope areas. As designed, the parking area provides a "buffer" of approximately 100 feet between steep slope areas and the proposed habitable structure. In our opinion, no additional buffers from the existing steep slopes or landslide hazard areas are necessary or recommended provided recommendations contained in this report are followed during construction and maintenance of the planned improvements. The uppermost wall of the upper parking area should be designed with an additional 4 feet of height (freeboard) above the retained slope. This freeboard will act as an impact wall to impede soil slumps reducing the potential for damage to the proposed structures. Some soil may slough over the freeboard and debris fence along the upslope side of the upper park ing lot if accumulated debris is not periodically removed from the behind the wall. It is possible that the wall could be overtopped during a worst case slide or seismic event. Debris fencing should be installed along the top of the impact wall. The debris fence should consist of a 4-foot-high cyclone fence above the 4-foot structural impact wall mentioned above. Access for small February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld -KE04520A2 -ProjeczsI20040520IKEIWP Page 6 Kennydole Cafe Renton, Washington Subsurface ExploraJion, Geologic Hazard, and Preliminary Geotechnical Engineering Repon Geologic Hazards and Mitigations equipment should be provided to maintain the area behind the catchment wall free from debris and maintain intended function. As with all slopes, surface drainage should be properly controlled and directed away from sloping areas. Downspouts from roofs should be tightlined into suitable storm water drainage systems. At no time should fill be pushed over the top of banle Uncontrolled fill over tops of slopes may promote landslides or debris flow activity. 6.0 SEISMIC HAZARDS AND RECOMMENDED MITIGATION Earthquakes occur in the Puget Lowland with great regularity. The vast majority of these events are small and are usually not felt by people. However, large earthquakes do occur as evidenced by the 1949, 7.2-magnitude event; the 1965, 6.5-magnitude event; and the 2001, 6.8-magnitude event. The 1949 earthquake appears to have been the largest in this region during recorded history and was centered in the Olympia area. Evaluation of earthquake return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. Generally, there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and 4) ground motion. The potential for each of these hazards to adversely impact the proposed project is discussed below. 6.1 Surficial Ground Rupture The nearest known fault trace to the project site is the Seattle Fault located approximately 7 miles to the north. Recent studies by the U.S. Geological Survey (e.g., Johnson et aI., 1994, Origin and Evolution of the Seattle Fault and Seattle Basin, Washington, Geology, v. 22, pp. 71-74; and Johnson et aI., 1999, Active Tectonics of the Seattle Fault and Central Puget Sound Washington -Implications for Earthquake Hazards, Geological Society of America Bulletin, July 1999, v. 111, n. 7, pp. 1042-1053) have provided evidence of surficial ground rupture along a northern splay of the Seattle Fault. The recognition of this fault splay is relatively new, and data pertaining to it are limited with the studies still ongoing. According to the U. S. Geological Survey studies, the latest movement of this fault was about 1,100 years ago when about 20 feet of surficial displacement took place. This displacement can presently be seen in the form of raised, wave-cut beach terraces along Alki Point in West Seattle and Restoration Point at the south end of Bainbridge Island. The recurrence interval of movement along this fault system is still unknown. although it is hypothesized to be in excess of several thousand years. Due to the suspected long recurrence interval, the potential for surficial ground rupture is considered to be low during the expected life of the proposed structures. February 27, 2006 ASSOCIATED EARTH SCIENCES. INC. MTlld -KE04520A2 -ProjectsI20040520\KE\WP Page 7 Kennydale Cafe Renton, Washington 6.2 Seismically Induced Landslides Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Geologic Hazards and Mitigations The potential risk of damage to the proposed development by seismically induced landsliding is discussed in Section 5.0. In general, ground motion associated with strong seismic shaking significantly increases the risk of shallow landsliding within the surficial site soil. 6.3 Liquefaction Liquefaction is a temporary loss in soil shear strength that can occur when loose granular soils below the ground water table are exposed to cyclic accelerations, such as those that occur during earthquakes. The observed site soils were generally dense and are not expected to be prone to liquefaction. A detailed liquefaction analysis was not completed as a part of this study, and none is warranted, in our opinion. 6.4 Ground Motion Based on the encountered stratigraphy, it is our opinion that any earthquake damage to the proposed structures, when founded on suitable foundation bearing strata in accordance with the recommendations provided in this report, would be caused by the intensity and acceleration associated with the event and not any of the above-discussed impacts. Design of the project should be consistent with 2003 International Building Code (lBC) guidelines. In accordance with the 2003 IBC, the following values should be used: Site Class C (Table 1615.1.1) Ss = 138% (Figure 1615[1]) SI = 48 % (Figure 1615[2]) 7.0 EROSION HAZARDS AND MITIGATION The sediments underlying the site generJlly contain silt and sand and will be sensitive to erosion, especially in the sloping portions of the site. In order to reduce the amount of sediment transport off the site during construction, the following recommendations should be followed. I) Silt fencing should be placed around the lower perimeter of all cleared area(s). The fencing should be periodically inspected and maintained, as necessary, to ensure proper function. 2) To the extent possible, earthwork-related construction should proceed during the drier periods of the year, and disturbed areas should be revegetated as soon as possible. Temporary erosion control measures should be maintained until permanent erosion control measures are established. February 27, 2006 ASSOCIATED EARTH SCIENCES. INC. MTJld -KE0452DA2 -Projectsl20040520lKEIWP Page 8 Kennydale Cafe Renton, Washington Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Geologic Hazards and Mitigations 3) Areas stripped of vegetation during construction should be mulched and hydroseeded, replanted as soon as possible, or otherwise protected. During winter construction, hydroseeded areas should be covered with clear plastic to facilitate grass growth. 4) If excavated soils are to be stockpiled on the site for reuse, measures should be taken to reduce the potential for erosion from the stockpile. These could include, but are not limited to, covering the pile with plastic sheeting, the use of low stockpiles in flat areas, and the use of straw bales/silt fences around pile perimeters. 5) Interceptor swales with rock check dams should be constructed to divert storm water from construction areas and to route collected storm water to an appropriate discharge location. 6) A rock construction entrance should be provided to reduce the amount of sediment transported off-site on truck tires. 7) All storm water from impermeable surfaces, including driveways and roofs, should be tightlined into approved facilities and not be directed onto or above steeply sloping areas. February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. Mflld -KE04520A2 -Projeclsl20040520lKF 1WP Page 9 Kennydale Cafe Renton, Washington Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations III. PRELIMINARY DESIGN RECOMMENDATIONS 8.0 INTRODUCTION Our exploration indicates that, from a geotechnical engineering standpoint, the proposed project is feasible provided the recommendations contained herein are properly followed. The bearing stratum ranges in depth beneath existing ground surface from approximately 2 to 8 feet. Conventional shallow foundations and standard pavement sections should perform well with proper subgrade preparation in most areas. 8.1 Site Preparation Site preparation of building and pavement areas should include removal of existing foundations, trees, brush, debris, and any other deleterious materials. All existing fill around the pre-existing structure should be removed from within building/pavement areas. Existing septic systems should be decommissioned in accordance with Renton Health Department requirements and removed from beneath any areas where structures or paving are planned. If any water wells exist on-site, they should be decommissioned by a licensed well driller in accordance with Washington Administrative Code (WAC) Section 173-160. If any heating oil storage tanks or other similar structures are present on-site, they should be decommissioned and removed in accordance with applicable Washington State Department of Ecology (Ecology) regulations. Any depressions below planned final grades caused by demolition activities should be backfilled with structural fill, as discussed under the Structural Fill section. Organic topsoil should be removed from areas where new buildings, paving, or other structures are planned. After stripping, remaining roots and stumps should be removed from structural areas. All soils disturbed by stripping and grubbing operations should be recompacted as described below for structural fill. Once excavation to sub grade elevation is complete, the resulting surface should be proof-rolled with a loaded dump truck or other suitable equipment. Any soft, loose, or yielding areas should be excavated to expose suitable bearing soils. The subgrade should then be compacted to at least 95 percent of the modified Proctor maximum dry density as determined by the ASTM:D 1557 test procedure. Structural fill can then be placed to achieve desired grades, if needed. 8.2 Site Disturbance Some of the on-site soils contain substantial fine-grained material that makes them moisture- sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld ~ KE04520A2 -Projectsl20040520lKE1WP Page 10 Kennydale Caft! Renton, Washington Subsuiface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Repon Preliminary Design Recommendations disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. 8.3 Winter Construction Based on the high in-situ moisture content of site soils observed during our February 2006 exploration, it may be necessary to dry a significant portion of site soils during favorable dry weather conditions to allow them to be reused in structural fill applications. If construction takes place in winter, drying is not expected to be feasible, and we anticipate that most or all of the site soils will be unsuitable for structural fill applications. Even during dry weather, site soils excavated for installation of buried utilities might not be suitable for utility backfill under paving or other structures. We recommend budgeting for backfill of buried utility trenches in structural areas with select, imported structural fill. If earthwork will be completed during winter months, we recommend budgeting to construct all structural fills with select, imported fill materials. For summer construction, significant, but unavoidable effort will be needed to scarify, aerate, and dry site soils to reduce moisture content prior to compaction in structural fill applications. Care should be taken to seal all earthwork areas during mass grading at the end of each workday by grading all surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils that will be reused in structural fill applications should be covered whenever rain is possible. If winter construction is expected, crushed rock fill could be used to provide construction staging areas. The stripped sub grade should be observed by the geotechnical engineer, and should then be covered with a geotextile fabric, such as Mirafi 500X or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer at least 10 inches thick in areas where construction equipment will be used. If desired, planned roadways can be paved with asphalt treated base (ATB) for construction staging, as described in the Pavement Recommendations section of this report. 8.4 Temporary Cut Slopes In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, we anticipate that temporary, unsupported cut slopes in the topsoil or disturbed/weathered pre-Fraser deposit soil can be planned at 1.5H:IV (Horizontal:Vertical) or flatter; temporary, unsupported cut slopes in the dense, unweathered, pre-Fraser deposit soil can be planned at IH:IV or flatter. These slope angles are for areas where ground water seepage is not encountered and assume that surface water is not allowed to flow across the temporary slope faces. If ground or surface water is present when the temporary excavation slopes are exposed, flatter slope angles will be required. As is typical with earthwork operations, some sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. In addition, WISHAfOSHA regulations should be followed at all times. February 27, 2006 ASSOCIATED EARTH SCIENCES. INC. MTlld -KE04520A2 + Projects\20040520IKEIWP Page 11 Kennydale Cafe Renton, Washington 9.0 PERMANENT SLOPES SubsU/jace Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations Permanent slopes proposed for the site should be planned at a gradient no steeper than 2.6H:IV. As with all slopes, surface drainage should be properly controlled and directed away from sloping areas. Downspouts from roofs should be tightlined into suitable storm water drainage systems. At no time should fill be pushed over the top of bank. Uncontrolled fill over tops of slopes may promote landslides or debris flow activity. 10.0 STRUCTURAL FILL Structural fill may be necessary to establish desired grades. All references to structural fill in this report refer to subgrade preparation, fill type, placement, and compaction of materials, as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. After stripping, planned excavation, and any required overexcavation have been performed to the satisfaction of the geotechnical engineer/engineering geologist, the exposed ground surface should be recompacted to 90 percent of ASTM:D 1557. In lieu of recompaction in areas where the subgrade contains too much moisture, we recommend that the stripped subgrade be overlain by an engineering stabilization fabric, such as AMOCO 2002 (or equivalent), with the edges of the fabric overlapped in accordance with the manufacturer's recommendations. A minimum of 12 inches of clean, free-draining structural fill compacted to a minimum of 95 percent of ASTM:D 1557 should be placed over the fabric. The structural fill should then be proof-rolled with a loaded dump truck to pretension the fabric and identify any soft spots in the fill. Upon completion of proof-rolling, additional structural fill should be placed, if necessary, to obtain desired grades. After recompaction of the exposed ground is tested and approved, or a free-draining rock course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts with each lift being compacted to 95 percent of ASTM:D 1557. In the case of roadway and utility trench filling, the backfill should be placed and compacted in accordance with codes and standards acceptable to the governing agency. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the locations of the perimeter footings or roadway edges before sloping down at a maximum angle of 2H: IV. Fill placed on slopes steeper than 5H: 1 V should be benched into dense till or suitable bedrock during grading to establish a good contact and minimize the potential for development of a slip plane. Benches should expose at least 4 feet (vertical) of strata acceptable to the geotechnical engineer or geologist. All fills proposed over a slope should be reviewed by our office prior to construction. February 27, 2006 ASS()ClATED EARTH SCIENCES, INC. MTlld -KE04520A2 -ProjecHI200405201KEIWP Page 12 Kennydale Cafe Renton, Washington SubsU/tace Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations The contractor should note that any proposed import fill soils must be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the material at least 72 hours in advance to perform a Proctor test and determine its field compaction standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No.4 sieve size) should be considered moisture-sensitive. Use of moisture-sensitive soil in structural fills should be limited to favorable dry weather and dry subgrade conditions. The on-site soils contained substantial amounts of silt and are considered highly moisture-sensitive when excavated and used as fill materials. We anticipate that due to mixing of soils as they are excavated, most excavated site soils will require aeration and drying prior to compaction in structural fill applications. Construction equipment traversing the site when the soils are wet can cause considerable disturbance. If fill is placed during wet weather or if proper compaction cannot be obtained, a select, import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus NO.4 sieve fraction and at least 25 percent retained on the No.4 sieve. 1l.0 FOUNDATIONS Spread footings may be used for building support when they are founded on approved structural fill placed as described above, or on suitable native stratum prepared as recommended in this report. Where existing fill is present below final grades, it should be removed and replaced with structural fill, which is also suitable for foundation support. Footings may be designed for an allowable foundation soil bearing pressure of 3,000 pounds per square foot (psI), including both dead and live loads. Footings supported entirely on unweathered, pre-Fraser deposit soil may be designed for an allowable foundation soil bearing pressure of 5,000 psf, including both dead and live loads. An increase of one-third may be used for short -term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost protection. However, all foundations must penetrate to the prescribed bearing stratum, and no foundations should be constructed in or above loose, organic, or existing fill soils. In addition, all footings must have a minimum width of 18 inches. Anticipated settlement of footings founded as recommended should be on the order of ')4 inch or less with differential settlement of 12 inch or less. However, disturbed material not removed from footing trenches prior to footing placement could result in increased settlements. All footing areas should be inspected by AESI prior to placing forms and steel to verify that the foundation subgrades are undisturbed and construction conforms to the recommendations February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTIld -KE04520A2 -Projecrsl20040520IKE\ WP Page 13 Kennydale Cafe Renton, Washington Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations contained in this report. Such inspections may be required by the City of Renton. Perimeter footing drains should be provided, as discussed under the section on Drainage Considerations. It should be noted that the area bounded by lines extending downward at IH: 1 V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of ASTM:D 1557. In addition, a 1.5H: 1 V line extending down and away from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the bearing soils. 12.0 FLOOR SUPPORT If crawl space floors are used, an impervious moisture barrier should be provided above the soil surface within the crawl space. Slab-on-grade floors may be used over medium dense to very dense native soils, or over structural fill placed as recommended in the Site Preparation and Structural Fill sections of this report. Slab-on-grade floors should be cast atop a minimum of 4 inches of pea gravel or "clean" crushed rock to act as a capillary break. The floors should also be protected from dampness by covering the capillary break layer with an impervious moisture barrier at least 10 mils in thickness. 13.0 DRAINAGE CONSIDERATIONS We observed ground water at a depth of 18 feet below ground surface in exploration borings EB-I and EB-2. Lenses of wet soils were observed in exploration borings EB-l and EB-2 suggesting the possibility of interflow within relatively permeable soil above less permeable soil. Therefore, prior to site work and construction, the contractor should be prepared to provide temporary drainage and subgrade protection, as necessary. All footing walls, basement walls, and retaining walls should be provided with a drain at the footing elevation. Drains should consist of rigid, perforated, polyvinyl chloride (PVC) pipe surrounded by washed pea gravel. The level of the perforations in the pipe should be set at the bottom of the footing at all locations, and the drain collectors should be constructed with sufficient gradient to allow gravity discharge away from the buildings. In addition, all foundation walls taller than 3 feet should be lined with a minimum, 12-inch-thick, washed gravel blanket that ties into the footing drain. The gravel blanket should extend up the back of the wall to within 1 foot of finished grade where less permeable soil can be used as a cap over the drain rock to reduce infiltration of surface water. Roof and surface runoff should not discharge into the footing drain system, but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to foundations should be sloped downward away from the structures to achieve surface drainage. FebrUilry 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld -KE04520A2 -Projeclsl20040520lKEIWP Page 14 Kennydale Cafi! Renton, Washington Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations 14.0 CAST-IN-PLACE RETAINING WALLS AND BASEMENT WALLS Walls that are free to yield laterally at least 0 1 percent of their height should be designed using "active" equivalent fluid pressures. Fully restrained, rigid walls that cannot yield should be designed using "at-rest" equivalent fluid pressures. The following table provides appropriate active, at-rest, and passive equivalent fluid pressures (and associated friction coefficients) for the anticipated project wall design conditions. For walls located adjacent to areas that are subject to vehicle traffic, a surcharge equivalent to 2 feet of retained soil should be added to the wall height in determining lateral design forces. Active At-Rest Passive Backslope Equivalent Equivalent Equivalent Conditions Fluid Pressure Fluid Pressure Fluid Pressure Friction Rock/Soil Type (Horizontal: Vertical) (pcf)' (pel) (pel) Coefficient Topsoil! Horizontal 50 70 200 0.20 disturbed soil Topsoill 2H: 1 V maximum 80 95 200 0.20 disturbed soil Structural fill Horizontal 35 55 300 0.35 Structural fill 2H: 1 V maximum 65 80 300 0.35 Unweathered Horizontal 30 50 350 0.40 pre-Fraser deposit soil Unweathered 2H: 1 V maximum 60 75 350 0.40 pre-Fraser deposit soil * pef -pounds per CUblC foot Lateral loads for footings may be designed using a combination of lateral sliding resistance along the bottom of footings and passive earth pressure against the sides of footings. Lateral sliding resistance may be determined by mUltiplying the dead load by the coefficient of friction listed for the appropriate stratum in the table presented above. Passive earth pressure (passive equivalent fluid pressure) should be assumed to be zero at the surface of the bearing stratum and may be assumed to increase with depth in bearing stratum at the rate indicated in the table. Lateral bearing and lateral sliding resistance may be combined. A II backfill behind walls or around foundation units should be placed as per our recommendations for structural fill and as described in this section of the report. Where east- in-place retaining walls face structural fill, the backfill should consist of on-site or imported granular fill compacted to 90 percent of ASTM:D 1557 using light compaction equipment only. A higher degree of compaction is not recommended, as this will increase the pressure acting on the wall. A lower compaction may result in settlement of slab-on-grades or other improvements placed above the walls. Thus, the compaction level is critical and must be tested by our firm during placement. Surcharges from adjacent footings, heavy construction equipment, or sloping ground (where not indicated) must be added to the above values. Februnry 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlid -KE04520A2 -Projecrsl20040520lKE1WP Page 15 Kennydale Cafe Renton, Washington Perimeter footing drains and wall backdrains discussed under Drainage Considerations. 14.1 Impact Walls Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations should be provided for all retaining walls, as In order to mitigate the potential risk of damage to the proposed structures by shallow-seated landsliding, we recommend that the retaining walls proposed for the upslope side of the upper parking lot be extended a minimum of 4 feet above the adjacent ground surface to act as a catchment for landslide debris that may come off of the upper slope. For design purposes, we estimated that a small debris flow could impact the proposed wall with a dynamic force of 500 pounds per horizontal foot of wall. This value assumes a debris flow with a mass of 125 pounds per cubic foot (pcf) traveling at a velocity of 6 feet per second. It must be understood that estimating the depth and speed of a debris flow is not an exact science. The structural engineer should note that no factors of safety were applied to our calculations; rather, we expect that the designer will apply an appropriate factor of safety to such a scenario. Our assumptions were based on the thickness of the weathered soil unit encountered on the slope above the proposed parking lot. However, future debris flows may vary from those estimated. As such, the owner must understand and accept the risk of building at the base of a slope and that future slope failures may damage the parking lot/garage and/or parked vehicles. Debris fencing should be installed along the top of the impact wall. The debris fence should consist of a 4-foot-high cyclone fence above the 4-foot structural impact wall mentioned above. Access for small equipment should be provided to maintain the area behind the impact wall free from debris and maintain intended function. The temporary cut to be made in surface soil exposed on the existing easterly ascending slope east of the proposed upper parking lot should be restored as soon as possible following wall construction to minimize the risk of surficial soil movement. Restoration may be accomplished by placement of structural fill in conformance with the recommendations presented in this report. 15.0 PAVEMENT RECOMMENDATIONS The proposed parking lot and access drive will either be constructed on undisturbed, dense native soils, or on structural fill placed am] compacted on top of these suitable native soils. Preparation of pavement sub grade areas ;hould follow the recommendations of the Site Preparation and Structural Fill sections of this report. The proposed subgrade, whether it is dense native soils or compacted structural fill, should have a minimum density of 95 percent based on the ASTM:D 1557 test procedure within the upper foot below the pavement section. Because much of the on-site soil encountered during exploration appeared to be above optimum moisture content at the time of our exploration program, remedial sub grade preparation might be required below the paving. Remedial preparation measures could include removal of some February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlid -KE04520A2 -Projecrsl20040520lKEIWP Page 16 Kennydale Cafi Renton, Washington Subsuiface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations of the existing site soils below the planned pavement section and restoring the planned subgrade elevation with select, imported structural fill, treating the native soil sub grade with Portland cement to stabilize the wet soils, or aeration and drying of existing soils prior to compaction of the road subgrades. We recommend that the final determination of how to prepare the road subgrades be made at the time of construction when weather and field conditions are known. Where roadways are built near the crest of a slope, such as the western edge of the upper parking lot, all fill beneath the roadway and within the roadway embankment should be properly keyed into the suitable native soils and compacted to 95 percent of ASTM:D 1557, as discussed in the previous section. Subsequent to compaction or recompaction, the subgrade should be proof-rolled with a loaded dump truck. Any deflecting areas or soft spots detected during proof-rolling should be excavated and replaced with properly compacted structural fill. Upon completion of any recompaction and proof-rolling, a pavement section consisting of 2V2 inches of asphalt concrete pavement (ACP) underlain by 4 inches of 1 \4-inch crushed surfacing base course is recommended for car parking areas. In driveway areas, a heavier section, consisting of a minimum of 3 inches of ACP underlain by 6 inches of 1 \4-inch crushed rock base course is recommended. The upper 1 inch of 1 \4-inch crushed rock can be replaced with 1 V2 inches of 5 Is-inch crushed rock as a leveling course, if desired. The crushed rock course must be compacted to at least 95 percent of the maximum density. All depths given are compacted depths, All paving materials, base course materials, and placement procedures should comply with suitable standard specifications, such as the Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal Construction, or other suitable specifications. All structural fill and all native subgrades less than 4 feet below fmished grade for a planned roadway should be compacted to 95 percent of the modified Proctor maximum dry density, as determined by ASTM:D 1557. Prior to structural fill placement or to placement of base course materials over native subgrades, the area should be proof-rolled under the observation of AESI with a loaded dump truck or other suitable equipment to identify any soft or yielding areas. Any soft or yielding areas should be repaired prior to continuing work, Depending on construction staging and desired performance, the crushed base course material may be substituted with ATB beneath the final asphalt surfacing. The substitution of ATB should be as follows: 4 inches of crushed rock can be substituted with 3 inches of A TB, and 6 inches of crushed rock may be substituted with 4 inches of ATB. ATB should be placed over a suitable native or structural fill sub grade compacted to minimum 95 percent minimum density, and a 1112-to 2-inch thickness of crushed rock to act as a working surface. If ATB is used for construction access and staging areas, some rutting and disturbance of the A TB surface should be expected, The general contractor should remove affected areas and replace them with properly compacted ATB prior to final surfacing, February 27, 2006 ASSOCIATED EARTH SCIENCES, INC. MTlld -KE04520A2 -Projeclsl20040520lKEIWP Page 17 Kennydale cafe Renton, Washington Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report Preliminary Design Recommendations 16.0 PROJECT DESIGN AND CONSTRUCTION MONITORING At the time of this report, site development plans, site grading plans, structural plans, and construction methods have not been finalized and the recommendations presented herein are preliminary. We are available to provide additional geotechnical consultation as the project design develops and possibly changes from that upon which this report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the foundations for buildings and of new pavement depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of the current scope of work. If these services are desired, please let us know and we will prepare a cost proposal. We have enjoyed working with you on this study and are confident that these recommendations will aid in the successful completion of your project. If you should have any questions or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Maire Thornton, P.E. Senior Project Engineer Attachments: Figure 1: Figure 2: Appendix: February 27, 2006 Vicinity Map Site and Exploration Plan Exploration Logs MTlld -KE04520A2 -ProjectsI20040520IKEIWP r ! I EXPIRES 11/20/ or Q Kurt D. Merriman, P.E. Principal Engineer ASSOCIATED EARTH SCIENCES, INC. Page 18 ~ N ~ A ~ a N ~ NO SCALE ~ a ~ " ~ m Associated Earth ~ c ~ ~ ~ Ii a N ~ <I Sciences, Inc. ~ 0 BJL T L~iJi.;i,H VICINITY MAP KENNYDALE CAFE RENTON, WASHINGTON , '" :'~~ , !~ '; ,Q FIGURE 1 DATE 2106 PROJ. NO, KE04520A ;:. ,/ ,00 30' -/ ~" ~ :: fOke Iros,,:., . //1/7910/7 t .ll 1 ~~ ~ SCALE: " = 30' ~ ~ Reference: Rick Anderson Architect, Floor Plan A1 #0205 -Dated 7-22-05 ""6's& -$? ..,./ U/Vd - / '.~ 10 ~./ / $/, /0 <l ~~ ~J" ? ?" -- ./ - ~ APPROXIMATE LOCATION OF EXPLORATION PIT TYP (09104) "'-. --- APPROXIMATE LOCATION OF EXPLORATION BORING TYP (02106) ~=================================================== t ASloclated Earth Sclencel, Inc. ~~ i ~ ~ [Ji ~ SITE AND EXPLORATION PLAN KENNYDALE CAFE RENTON, WASHINGTON FIGURE 2 DATE 2106 PROJ. NO. KE04520A APPENDIX LOG OF EXPLORATION PIT NO. EP-1 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read tqgether with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simptfication of actual conditions encountered. DESCRIPTION Topsoil Loose, dry 10 damp, dark brown, silty fine SAND, root hairs. 1 - 2 - - - - - - - - - - - - - - - - - - - - --Pre FraserDeposlt - ---- - ---- - - - - - - - - - --- Medium dense to dense, damp, light brown, SILT, consolidated, horizontal stratification. 3 -,-Dense-;-darrip,-gray,line-to coarse SAND wlth-gravefand-cobbies. horfzo-ntalstratificatlon.-- - - --- 4 -1 5 - 6 Bottom of exploration pit at depth 6 feet No ground water/seepage. Slightly caving within sand. 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - ~ 20 ~--------------------------------------------------------------------------------------------,c I ~ ~ ~ ~ ~ ~ ~ M ~ r Logged by: MT Approved by: Pool Brothers-Lake Washington Boulevard-Renton Renton, WA Associated Earth Sciences, Inc. ~~~[J4~ Project No. KE04520A September 2004 ~--------------------------------------------------------------------------------------------- 1 - LOG OF EXPLORATION PIT NO. EP-2 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage oftime. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil Loose, dry to damp, dark brown, silty fine to medium SAND, root hairs. 2 -L ____________________________________________________ _ I Pre Fraser Deposit 3 --l i 4 -Medium dense to dense, damp, light brown, SILTSTONE, horizontal stratification. 5 - 6 - 7 - 8 9 - 10 - 11 - 12 13 14 15 - 16 - 17 18 - 19 i Bottom of exploration pit at depth 8 feet No ground water/seepage. No caving. 8--~2~O-------------------N ____________________________________________________________ __ '"' ~ '" ~ ~ M t; Logged by: MT Approved by: Pool Brothers-Lake Washington Boulevard-Renton Renton, WA Associated Earth Sciences, Inc. ~~~~~ Project No. KE04520A September 2004 ~--------------------------------------------------------------------------------------- g R '" o LOG OF EXPLORATION PIT NO. EP-3 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read togetner with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered, DESCRIPTION Topsoil 1 -Loose, dry to damp, dark brown, silty fine to medium SAND. 2 - 3 -------------------------------------------------------Pre Fraser Deposits" Weathered 4 -Medium dense, damp, light brown, fine sandy SILT, silty fine SAND, few root hairs. 5 -I--- - - - - - - - - - - - - - - --Pre-Fraser-Deposits --:: Unweathered-- - - - - - - - - - - - - - --- 6 -Dense, damp, light brown to light gray, SILTSTONE. 7 - 8 ~---------------------- 9 - 10 - 11 - 12 - 13 - 14 15 -- 16 17 - 18 - 19 - Bottom of exploration pit at depth 8 feet No ground water/seepage. No caving. § 20 ~--------------------------------------------------------------------------------------- ~ Pool Brothers-Lake Washington Boulevard-Renton ~ Renton, WA ~ ~ Logged by: MT Approved by: Associated Earth Sciences, Inc. ~~~~~ Project No. KE04520A September 2004 ~ -------------------------------------------------------------- LOG OF EXPLORATION PIT NO. EP-4 --------------------------------------,-- This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplfication of actual conditions encountered. DESCRIPTION Topsoil 1 ,=-oS'~Ld...rYJQ. ,!a..r:np,_d~r!5 QrQ""n-,-~I!y .!i,,-eJ~fl2~!Y'!l§~f'!.~ !.oQ~h~i~,--______________ ...J Pre Fraser Deposits 2 - Medium dense to dense, damp, light brown to gray, SANDY GRAVEL with cobble, stratified. 3 - 4 5 - 6 -Sandier at 6'. 7 - 8 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Dense, moist, light gray, fine sandy SILT. Bottom of exploration pit at depth 8 feet No ground water/seepage. No caving. ~~~o---------------------------a :--------------------------------------------------------------------------------------- "" ~ ~ ~ ~ ~ " ~ <l M := Logged by: MT Approved by: Pool Brothers-Lake Washington Boulevard-Renton Renton, WA Project No. KE04520A September 2004 Associated Earth Sciences, Inc. ~~~~~ ~--------------------------------------------------------------------------------------- LOG OF EXPLORATION PIT NO. EP-5 r----,------------~ -------------------------,----0 This log is part of the report prepared by Associated Earth Sciences, Inc. (AESI) for the named project and should be read together with that report for complete interpretation. This summary applies only to the location of this trench at the time of excavation. Subsurface conditions may change at this location with the passage of time. The data presented are a simplficatlon of actual conditions encountered. DESCRIPTION Topsoil 1 -Loose, dry to damp, dark brown, silty fine to medium SAND, roots. 2 - r-----------------------------------------------------Pre Fraser Deposits· Weathered 3 - Medium dense, damp, light gray, fine sandy SILT, few roots. 4 - 6 -~Dense, damp, light gray, SILTSTONE. 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - Bottom of exploration pit at depth 6 feet No ground water/seepage. No caving. r §-~20r------------------------------------:--------------------------------------------------------------------------------------- M ~ Logged by: MT Approved by: Pool Brothers-Lake Washington Boulevard-Renton Renton, WA Associated Earth Sciences, Inc. ~~~[!j~ Project No. KE04520A September 2004 ~--------------------------------------------------------------------------------------- Associated Earth Sciences, Inc. Exploration Log ~ ~ n [!i 0 Project Number I Exploration Number I Sheet KE04520A EB-1 1 of 1 Project Name Kennj'dale Cafe Ground Surface Elevation (ft) Location Renton WA Datum i'JIA Driller/Equipment CN Drillin~ Date StarUFinish 219106,219106 Hammer Weight/Drop 14Q# /30' Hole Diameler (in) - g ~ ~ = * w u-0 .-0 ",Ie .!1 '<=.0 Iii 1 Blows/Foot '" .<= 0. o.E --'w f-a s E i"» 5:E" ~ '" :;; .!!.Q '" T ro ClU) ~Ill .<= 0 U) 0 i5 DESCRIPTION t) 10 20 30 40 S-1 Topsoil/Disturbed Soil 3 ""~ Moist, dark brown to orange·brown, silty fine SAND, organic roots. 4 4 S-2 Moist to very moist, light orange-brown, fine to coarse SAND. 2 "". 3 3 l-S r-0La.!l9~ @i!1a1LofL $taiDing-.at~Q[It9._cL few_rOi)~. ______________ S-3 4 "" Pre-Fraser Deposit 4 Very moist to wet, olive-brown, fine to very fine SAND, trace silt 3 I S-4 Very moist to wet, olive-brown, very fine SAND with silt, horizontal 3 "'" stratification. 7 B 1-10 I S-5 Wet with depth, stratified horizontal lenses of orange oxidation. 4 "'" B 7 S-6 Wet, olive-brown to gray, fine to medium SAND to fine sandy SILT, 7 horizontal stratification. 13 29 ,. 15 Wet, olive, fine SAND with silt, horizontal light orange oxidation zones. S-7 23 33 66 33 S-8 Wet, olive-brown, SILT/fine SAND to wet, gray, medium to coarse SAND, :!. 23 slight orange oxidation. 32 7. 44 20 Wet, gray, medium to coarse SAND. 33 S-9 0/ 501 " S-10 Wet. ara.v. fine to coarse SAND to wet olive-brown, SILT. 0/ 501 " Bottom of exploration boring at 23 feet I-25 30 I 35 I ~ I • I 2 I • I Sampler Type (ST); rn 2" 00 Split Spoon Sampler (SPT) 0 No Recovery M -Moisture Logged by: MT rn 3" 00 Split Spoon Sampler (D & M) Il Ring Sample '¥-Water Level () Approved by: ~ Grab Sample 0 Shelby Tube Sample.t: Water Level at time of drilling (ATD) Associated Earth Sciences, Inc. Exploration Log ~ ~ ~ ~ ~ ---- Project Number I Exploration Number I Sheet KE04520A EB-2 1 of 1 Project Name K!lnn~dale Cafe Ground Surface Elevation 1ft) Location Renton WA ----Datum tIIllI Driller/Equipment CN Drillin~ Date Start/Finish 219106,219106 Hammer WeighUDrop 140# 13Q' Hole Diameter (in) ---- c ~ = ~ g '" <>-0 ;; ., .-0 =~ .,!!1 Blows/Foot ~ ~ 0. ~"" --'~ I-o.E ~-~ ~ 15. S E I!!,., 5:~ .!.Q ~ ~ T '" CJUl 0 gal 5 0 Ul DESCRIPTION u 10 20 30 40 0 ~ Disturbed Soil 1 S-l Wet, olive-brown, silty fine SAND. 1 ""2 1 [ S-2 Wet. olive-brown, silty fine SAND. 2 ""6 2 4 5 [ --------------------------------- S-3 Pre-Fraser Deposit 6 1"11 Wet, olive-brown, silty fine SAND to fine SAND, faint horizontal 6 stratification. s [ S-4 Wet, olive-brown, fine SAND, trace silt, faint horizontal stratification. 7 ""34 I Very moist. gray, medium to coarse SAND. 13 21 10 [ Wet, olive-brown, fine SAND, trace silt, faint horizontal stratification. 5-5 • "" 7 20 27 , 15 [ Very moist, olive and gray, fine SAND/SIL T and coarse SAND, faint 5-6 16 "" 7 horizontal stratification, interbedded. 23 24 Gravelly at 17'. '" 20 Bottom at exploration boring at 20.5 feet 25 30 35 I , , , , , ~ I • 2 . -Sampler Type (ST): rn 2" 00 Split Spoon Sampler ISPT) 0 No Recovery M -Moisture logged by: MT rn 3" 00 Split Spoon Sampler 10 & M) IJ Ring Sample '¥ Water Level 0 Approved by: '~ Grab Sample [] Shelby Tube Sample.!. Water Level at time of drilling (A TO)