No preview available
HomeMy WebLinkAbout03652 - Technical Information Report NELSON PLAT LUA 11-088 NE 12TH STREET and MONTEREY AVENUE NE Renton, Washington TECHNICAL INFORMATION REPORT June 25, 2012 Revised August 8, 2012 Prepared for: Signature Custom Homes of WA, LLC Anthony Hines P.O. Box 1910 Milton, Washington 98354 (253) 606-1370 office Submitted/Prepared by: L. O _�_ Offe Engineers, PLLCVo wAs Darrell Offe, P.E. - � 13932 SE 159th Place Renton, Washington 98058-7832 ' • (425) 260-3412 office '' J.Sf, (425) 227-9460 faxg� QIS10 T t �\ , ,�A �`S-/ONAL EXPIRES 3 ea,S7 Project Description The proposed Nelson Plat is an approved 9 lot single family residential subdivision situated on an existing lot with a total area of 1.63 acres. The property is located on the north side of NE 12th Street, at the extension of Monterey Avenue NE. The current site address is 2008 NE 12th Street. The existing use of the parcel is a single family residence situated in the middle of the property with a large looping driveway circling the house. The remaining property is lawn with scrubs located on the property line. The existing house and outbuilding are proposed to be removed for this development. The properties to the south, north, and east are developed as single family. The properties to the west are large lots with single family homes. The proposed development will allow access from Monterey Avenue from the north and connect with NE 12th Street to the south. Frontage improvements along NE 12th are proposed and include landscaping, sidewalk and curb/gutter improvements. The dedication of Monterey Avenue NE is proposed as part of this project. The existing King County Tax Parcel number is 334390-2520. There are no sensitive areas on this site. The steepest slope is approx. 10% near the southwest corner of the property. The soils on the site have been identified by a Geotechnical Engineers as "clean sands"suitable for infiltration. A copy of the Geotechnical report has been attached to this report. - 7 - Review of Resources Resources reviewed for this project include: City of Renton existing and potential flooding and erosion data, utility system maps, FEMA maps, sensitive areas folios, USDA sols reports, King County Soils Survey, wetland inventory maps, Renton erosion maps, and Renton landslide maps. Critical Drainage Area Map • John's Creek / Lake Washington Watershed Flood plain/floodway (FEMA) Maps • There is no mapped floodplain in the immediate area per the available FEMA map. Sensitive Areas • Streams and 100 Year Flood Plains—There are no streams or floodplains on the project. • Erosion Hazard Areas—There are no landslide hazard areas on this project. • Landslide Hazard Areas—There are no designated sensitive slopes on or adjoining the property. • Seismic Hazard Areas—The area is not mapped as a seismic hazard area. • Coal Mine Hazard Areas — The property does not appear to be located within a designed coalmine hazard area. • Groundwater Protection Areas - The project area is within the City of Renton Zone 2 aquifer protection area. U.S. Department of Agriculture, King County Soils Survey • The soils on the site are classified as Indianola loamy find sand (INC), between 4% to 10% slopes. These soils types are described in the Soil Survey of King County Area, Washington (Soil Conservation Service [SCS], 1973). INC soils are typically excessively drained soils with the water table more than 80 inches deep. Normally a sandy layer is present at 30 to 60 inches deep. A soils report was conducted by S&EE, Inc., Dr. CJ Shin a geotechnical engineer. Part of the conclusion of the report, provides an infiltration rate is 3.0 inches per hour with a factor of safety of 3, the rate is 1.0 inches per hour for the sandy material. Therefore individual lot BMPs will be used as part of this project. - 7 - Flow Control / Water Quality design — The project would be required to meet the 2009 KC Drainage Manual (Modified by the City of Renton) for design and sizing. Field Inspection Offe Engineers has visited the site on several occasions during the past two months. The most resent visit occurred the morning of June 20, 2012. The ground slopes from the north east corner to the south west corner, along NE 12th Street. The drainage flows into an existing conveyance system in NE12th. The downstream system was walked from the CB on Ne 12th to the west. A portion of the downstream system was no visible due to heavy vegetation cover and steep slopes. This downstream area was to the west of Lincoln Place NE and NE 12th Street intersection. This area of the downstream was not visible for inspection from above or below, near Park and I-405. It will be assumed that the system is functioning adequately for capacity due to the gradient; however since no visible inspection was made, Offe Engineers will hold the developed condition 100 year flow rate to match existing conditions Review of the 8 Core Requirements and 5 Special Requirements of the 2005 King County Surface Water Design Manual Offe Engineers has reviewed the Core and Special Requirements in Chapter 1 of the King County Surface Water Design Manual, and addresses each of the requirements as follows: Core Requirement No. Z —Discharge at Natural Location The current property has one point of discharge; southwest corner if runoff does occur from the property. The existing site currently sheet flows across the property to the southwest property corner. It accumulates in the southwest corner and runs into NE 12th where the runoff is collected into an existing conveyance system. The proposed drainage system will collect the runoff from the new road and convey to this point. On each lot, infiltration dry- wells of trench drains will be used to mitigate future runoff. Core Requirement No. 2—Offsite Analysis The upstream areas of the project site includes three single family homes to the east on NE 12th and homes to the north along Monterey. The homes to the east, along NE 12th slope towards 12th. There does not appear to be any point of discharge from these properties on the Nelson Plat. The area appears to have well drained soils reducing or eliminating runoff from entering the property. The development to the north, on Monterey, intercepts the runoff into a vault located in the middle of the street and an infiltration pipe lying along the east side of Monterey Avenue NE. No runoff is entering the Nelson property from the north. C - 7 - ( Core Requirement No. 3—Flow Control The property is located within the City of Renton, peak flow rate control standards — (existing site conditions). The storm water runoff form the 7 of the lots are proposed to be mitigated by using infiltration BMP's — gravel filled trench or dry wells. The other two lots are proposed to use perforated pipe connection together with impervious coverage restrictions. By providing these BMP's, the existing and developed conditions have been analyzed as part of this report and it has been determined no further storm water flow controls are required. All the proposed runoff of the road way onsite will be collected and conveyed to the storm water system then discharge into the existing system within NE 12th . Core Requirement No. 4—Conveyance System The proposed on-site conveyance improvements will include curb, catch basins and a pipe network for collection of surface runoff from landscape, driveways, roadways, and sidewalks. Storm water conveyance calculations have been provided as part of this report. The proposed runoff was analyzed at the 100 year event— 15 minute intervals. This is greater than the required 25 year event, since the property is small and the conveyance system has plenty of grade, a larger storm event was chosen to prove no overtopping occurs at even the 100 year event. There are no storm structures that overtop at 100 year event; most structures have 2 feet of free board. Core Requirement No. 5—Erosion and Sediment Control A Temporary Erosion and Sediment Control Plan implementing the Best Management Practices will be designed as part of the final engineering plans for the project in accordance with City of Renton requirements. The temporary pond facility has been sized using the 2 year— 15 minute interval storm event. The calculations for the temp. pond are included within this report. Core Requirement No. 6—Maintenance and Operations The Maintenance and Operations for the Nelson Plat include both a public and private system. Within this report are the maintenance requirements for the facilities being installed as part of the plat and the facilities to be installed as part of the residential building permits. Core Requirement No. 7—Financial Guarantees and Liability The Financial Guarantees and Liabilities will be required prior to the project being finalized by the City of Renton. Bond Quantity worksheets are provided within this report. Core Requirement No. 8— Water Quality The project is not required to provide water quality facilities. The project does not exceed 5,000 square feet of new PGIS (pollution generating impervious surface). Special Requirement No. 1 —Adopted Area-Specific Requirements There is no special overlay or requirements within the City of Renton that affect this property. Special Requirement No. 2—Floodplain/Floodway Delineation This requirement does not apply. - 7 - ( Special Requirement No, 3—Flood Protection Facilities This requirement does not apply. Special Requirement No. 4—Source Controls This requirement does not apply because the project is located in the basic water quality treatment area. Special Requirement No. 5—Oil Control This requirement does not apply. - 7 - DRAINAGE CALCUAL TIONS-refer to attached "breakdown of basin" PRE-DEVELOPED DRAINAGE The drainage from the existing site currently sheet flows towards southwest corner, which is the low area of the site. The existing site area is characterized by lawn, a circular asphalt driveway, a large house and stand-alone garage. There are no drainage improvements on the site. The property fronts along NE 12th and abuts the southerly end of Monterey Ave to the north. The existing site conditions were modeled as: Imperious Area: 0.08 acres (house/garage/walkways) P.G.I.S. Asphalt driveway: 0.24 acres Grass: 1.31 acres The existing drainage analysis was performed using the "KCRTS" hydrology software and its summary tables and charts are attached for reference. The methods outlined in the 2005 King County Surface Water Drainage Manual were used as guidelines. Existing Modeling: 2 year peak flow: 0.09 cfs 10 year peak flow: 0.12 cfs 100 year peak flow: 0.25 cfs total area: 1.63 acres DEVELOPED DRAINAGE The developed project runoff will consist of the existing roadway (Monterey) and two lots (lot 5 and 6). These two lots will utilize perforated pipe connection to the roadway conveyance system. Based upon the setback requirements for infiltration, the proposed dry wells and trench will reduce the building envelopes on these lots below the owner's desire. The rest of the lots will utilize full infiltration and therefore be removed from the runoff modeling, per the 2009 Manual. The Developed Condition includes: Impervious Area: 0.37 acres Grass: 0.61 acres Developed Modeling: 2 year peak flow: 0.10 cfs 10 year peak flow: 0.13 cfs 100 year peak flow: 0.22 cfs _ 7 - � Comparison of Runoff:- Condition unoffCondition 2 year event 10 year event 100 year event Existing 0.09 cfs 0.12 cfs 0.25 cfs Developed 0.10 cfs 0.13 cfs 0,22 cfs DIFFERENCE 0.01 0,01 -0,03 Conclusion Based upon the above comparison of runoff, the proposed project DOES NOT require storm water flow control. WATER QUALITY REQUIREMENTS: The existing condition consists of 0.24 acres <10,300 sq. feet> of Pollution Generating Imperious Surfaces (PGIS) from the asphalt driveway. The developed condition would consist of 0.15 acres <6,540 sq. feet> of proposed Monterey and NE 12th widening. This would be a net REDUCTION of PGIS of -3,760 square feet which is less than the threshold of adding 2,000 new square feet. Therefore the project DOES NOT water quality treatment. Proposed Mitigation: Several items have been proposed to mitigate the reduction of storm water impacts from this project and are included within the construction plans: (A) Reduction of 3,760 square feet of PGIS by means of the road modification to Monterey Avenue NE and the elimination of the existing asphalt driveway/parking areas; (B) Infiltrating runoff from 7 of the proposed 9 lots by: a. Infiltration Dry wells b. Infiltration trenches (C) Providing perforated storm pipe connections for lots 5 and 6 to the new storm system (D)Provide impervious area restrictions to Lots 5 and 6 AND (E) Reducing the amount of impervious area runoff as to reduce the 100 year storm event below the existing condition. C - 7 - ( APPENDIX A- CALCULATIONS 1. Temp. pond sizing Z. Storm water runoff(existing/developed) 3. Conveyance / backwater analysis B- PROPOSED BMP's C- MAINTENANCE OF BMP's D- BOND QUANTITY WORKSHEET E- OFF SITE ANALYSIS F- GEOTECH REPORT c A - CALCULATIONS f ( 1 — Temp. pond sizing ,G�/! Area .1 Till Forest 0.00 acres _ � (QZ) Till Pasture 0.00 acres Till Grass 1.63 acres (9, 099V&I Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass 0.00 acres _ 2 (o. #6) Wetland 0.00 acres Impervious 0.00 acres,, e)' �.� Total ------ 1.63 acres' z 2V . f 7 Scale Factor : 1.00 15-Min Reduced A, .- 4,Hob-9.,,A rr Edit Flow Paths I Time Series: TESC »I I Compute Time Series 4 f'(C 16-6)W ��� "`-� Modify User Input I A, A co27 File for computed Time Series [.TSF] _ I _ (3.4 6(3.71 rrgG .HeIp/Flet:1CCHTS �7.112_<1 Flow Frequency Analysis Time Series File: tesc. tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- w, Flow Frequency Analysis Flow Rate Rank Time of Peak "`- - Peaks - - Rank Return Prob (CFS) N (CFS) Period 0. 193 4 2/09/01 12: 45 0 .823 1 100.00 0.990 0. 092 7 1/06/02 1 :00 0 .512 2 25 . 00 0 .960 0. 357 3 12/08/02 17: 15 0.357 3 10.00 0.900 0.031 8 8/26/04 1 :00 0.193 4 5 . 00 0.800 0 .512 2 11/17/04 5:00 0 5 3 .00 0.667 0. 145 6 1/18/06 15:00 ' 6 2. 00 0.500 0. 151 S 11/24/06 1 :00 ' I ' 7 1 . 30 0.231 0.823 1 1/09/08 6 : 30 0.031 8 1 .10 0. 091 Computed Peaks 0.720 50 .00 0 .980 4[ 1 i 2 — Storm water runoff BREAKDOWN OF BASINS June 15, 2012 Existing Site Conditions Total P.G.I.S. Outwash Area Impervious Asphalt Grass Forest Notes SITE 1,63 ac 0.08 ac 0,24 ac 1.31 ac 0.00 ac KCRTS Input Parameters 1,63 ac Developed Site Conditions SITE Total Max. Design Outwash Area Impervious Impervious Grass Forest Notes Public R/W 10,457 sf - 2,150 sf 1,767 sf 0 sf (2150)Sidewalk including frontage P.G.I.S. 6,540 sf (5900)Pavement plus D/W's(640) Lot 1 10,291 sf 4,000 sf 0 sf 6,291 sf 0 sf Full Infiltration Design for House&D/W Lot 2 5,838 sf 4,000 sf 0 sf 1,838 sf 0 sf Full Infiltration Design for House&D/W Lot 3 6,337 sf 4,000 sf 0 sf 2,337 sf 0 sf Full Infiltration Design for House&D/W Lot 4 5,782 sf 4,000 sf 0 sf 1,782 sf 0 sf Full Infiltration Design for House&D/W Lot 5 6,862 sf 4,000 sf 4,000 sf 2,862 sf 0 sf Perf. Pipe Release Lot 6 4,778 sf 3,583 sf 3,583 sf 1,195 sf 0 sf Perf. Pipe Release Lot 7 6,635 sf 4,000 sf 0 sf 2,635 sf 0 sf Full Infiltration Design for House&D/W Lot 8 6,002 sf 4,000 sf 0 sf 2,002 sf 0 sf Full Infiltration Design for House&D/W Lot 9 7,954 sf 4,000 sf 0 sf 3,954 sf 0 sf Full Infiltration Design for House&D/W Total(Sq.Feet) 70,936 sf 35,583 sf 16,173 sf 26,663 sf 0 sf Totals(Acres) 1.63 ac 0.37 ac 0.61 ac 0.00 ac KCRTS Input Parameters Maximum Impervious calculation-R-8(75%)for lots 1-9 OR 4,000 square feet WHICHEVER is less. Referenco.e 11-A , 7c r 0.: 41.' il �� �� ' , Flow Control Standards 666 1114 ,R Peak Rate Flow Control Standard(Existing Site Conditions) ,' Flow Control Duration Standard(Existing Site Conditions) -111f 11 �S .. ,,,,,„r,„„. Flow Control Duration Standard(Forested Conditions) .••.k'. T..-.q F 1.......�Renton City Limits 4. , Pik C.:3PotentialAnnexationArea a• i 1A. )638th SI \- ��j e .144 aN 3S11)St II %N33rd PI 57 '9P W31Si Y \P F '- - ).J' to W " •\\ 41h 51 NE 25th SI � e Afilh 7k��[ SI iQ d ..11 SI NE 20th Pt i • W < ■■ 02 \411' �� i 1 G ` Wim' ��Irii . ` � �` 1 e �, p �fry n �y E, ikii� el��l `•, , - - ,:•�' � ;u, Fmm__'Al 6E 12th S1 9YmS <� gir : © .�,i_q �'I r'h s, NI'81h si SE 12ph ' 1' g 2 �� �r. NE lib Si z.. e1• SW,20th St , ''_� Il,lt� ���1� I - _' `•,�,, f Y, h PI Z. w 1 ` S_,2,..q S J'� ,,$ 11 1 Li.19 '� ,ice \SE 2" PI '1i1/ii �1't. ��e Em��,._ y .] . N 40,,,, :,,.r_�r`r r 4th 51 .0 w W I t Ltite1r'1,1 q /-_JI •,-- 1 • I —+�Fy�a 1 a'`�:•1 s, .r_,i I Mr h+ ,I' c Nr i��a-;I '�' _ S- :2nd.,I 4-�)., r -.- t'-' ' 71L&_...,"I 53rd Si .,7H yf,,,, IL‘''',. St 3,dP�..1 11 -..�umi { i IIsm \��AA�l,,,,__ n a!p '169 L,5`St -S _ - 71 ii, `d -• e m 1406 _ I >~l'ry, k�- a '1"- , I �� N- _o a .,.•�ml g �%l s ,;.gid 5 y W,p. w \ 9 ��'° ..4 L' • Ra ` Fr- A. 1• ,2 y k'S0 Q� � Me N Vel Rd Cotler R. i C.' S23rt1$Iw SE 1601St -,59th P' ... tt ; = W .--TT ; "SF7B' - e..-. 16gp PI i C p N w a M m < . N ' • i.L W a. SW 27th Si p N < a' b m �. . ca 1� wO s u u ry ` 6 a i' ! . _ 332nd S7�..2. $ ��''� < SE a •68th Sl 1 I W SC 1tOI[ LL m 3 SW134th •' 16 _ :,i, �,° m • -96th PI S'E 172nd PI "s ostco D 1 S W 39th St �6- Pd m.vi m w 1. i < s�� P tYooa SW4Int St m i W F� 1 << u 61, P\ Lica '„ /.-..-..- Ni 1� . , SA�� •-gym o SE 160th St SE 11�h SE Pe v Aia'R am! -fQ ' a a S: / SE 1e4m St - .\_Rd e t,5 3 _46... T, -,841h P,,lEi.,..14, S 188th St n n ',..,_° / 'b SE 1B710-81- - _ . 19gh Y m m w t • W SE IV �� SE 188th St '" _ S 190th St; rn "' eY 44 d. y . • ..__... �' 1611St w S 3T,.-moi 4.... m _Q S 55th Si r .. W. ...._ <.W m: W ,� �P 19z�d°` m 164th St ! . m 960 E x m learn Q: '.D. m 1 ¢'L <' ,. - -- - -_.. '.m s 290th St > - rn a -{J4•...-..-..-. -.- -, SE tooth Sim ¢' • d ' d m 01 a o Q r s a < Q r ° o w o a' y o m t SE 204th.r g� w•Nt-_ 5 m 'n: :0'*c SE 208th St� •S�,bm.t,SI '�f < _ S a 1 0 _ -- Flow Control Application Map + Printed 1/14/2010 0 1 2 Miles EXISTING CONDITIONS -- RIM=268.22' 0^_' RIM=269.23' IE 12"CPP E=264.87' cm12"N/S IE 12"CPP S=264.82' D • 4 CTR CHNL=256.73' D W W V BLE �� I ' of RIM 2MP N SURVEY SS ,S IE 36'CMP N 262.04' SUMP=257.52' I5.V , . di . N D1jIYEWAY .it 13RIVEWAY.-. WOOD FENCE p ) •y: 000 FENCE 3 t4-'-,OT l2� `•.... . DL#1 DL#2 •-.,, ;0.5' A WOOD FENCE • AL 5 0.T • ��•� COR.S 0.4' BAR W/CAP I / 000 FENCE �� ""'—' . mm ammo• •• ' —WAI NGER S 0.7' ' ? c WOOD FENCE COR v r �' C ON SO.TXE0.9' . 1.3'EDGE CON . 17.67 • F a UND MAG 1NASHER / FOUND MAGANASHERDR STRONG 15986 f 10.57 4R STRONG 15966/ ON-LINE CORW0 DFENCE \ !, I ) . /8/20/2011 / 8/20/2011 GR/0.5� GARAGE i/ ( S 8'X E 0.1' ACCEPTED / ACCEPT FEN a / \ V * I N GRASS\1 I / / i / ! ONI 1 V \ 1 1 a FEN 1 W.c t v1 I ® /'OIL LOG I o : \' ' / z AP•ROXIMATE LOCATION n 11PE CITY OF RE1�ON / / D T$ I I j / GRASS�274 r N / Ili2"AP�LE I I N �^ / FOUI `` 102"A I I I ��� SOIL2LOG ® 0.2 N ` 8/20/ I\t I I ' I / SSCO FE ah \ W e'1APPLE 2"APPLE I / I :OF /GFE=275.1DRIVELV, , Or JI II I I HOUSE_ 2"APPLF� ' 2STORYr� �� � ODFEDAc'll��)`_-130 ' I w�11FE=278.328,3 , �- I � a I I S s=�fie/ iGPL CATE �c ENI F I 1 I I DRIVEWAY �I 7 4 �J I GFE=267.50 �� � a I N *441tiN 1/1- i O I I �i�� s �_ I, r')1?'(/ I I 11 1 c � \ {' 1 $ � I 1 a LOTS s J F 1 I y*� 11$3.4 '� AREA = 70,742 SQ. FT. ..il ° # I VI \o g 1 \ I \ N \ \\ 1 "2 ACRES \ #',' I 1 ,3,-, I 123.1,\ \\ GRASS .?...> I ni 1 I,' \ Z N ?k- A \ 1 �\ ER POLE 11 1 ~ \ \0 \ \\ \y c . tli i FanU 1"k N� \ GRASS \ N \ * GRASSiiit :...,. ... k i�"1" i f AQPROXIMA+LOCATION 0 \ \ ''i:W! PE CITY OF ENTON , Li. k \ SEWER ASBUIL(S `cp„..1 e \ I \ \ ° \ SOIL LOG \ I 1 1"i m _ •::"47,::,"::. SOIL L G AP li = 1�— \ \ \ 'BUND 1/D REBAR W/ AP �1 v."':+ SDMH \ \ LS 0.5525 OY R 20"PR F. RIM=255.4 0\�3 W II 17 0. \,11II IE 12"CMP W\\53.60' \ \ \ 8/20/201/..., ' •'� 8. 41,1•1114/11 ifs Ala.0.4.1r.16. �lett MlSl�.eg' --,2*>r, iiitac ,it40.0D,1�:�.Om.,.��..L-/.1 20"P - ���..• I 111111110111111 :*AILA.. -- _ _ Co, mop W S o ` •3 SS E . � 89°33 252.26' S-S—�� SS� Nd a`tr � ._. N TBMB 455.97'(MEAS.) \ L. FVC FVC i� CRASS 4�fik, Ns, *Via.41 DRIVEWAY �1 r�RIVEVJP SIG `HCR (F. HCR -- — — — — — — EXISTING CONDITIONS Liind Usik6ununaly U xl r Area J Till Forest 0.00 acres Till Pasture 0.00 acres Till Grass 0.00 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass 1.31 acres Wetland 0.00 acres Impervious 0.32 acres Total 1 1.63 acres Scale Factor : 1.00 Hourly Reduced Time Series: Pre-Dev Nelson »I Compute Time Series Modify User Input File for computed Time Series [.TSF] _ i, . c.., Flow Frequency Analysis Time Series Fil_ : .re-dev nelson. ts Project Location:Sea- - ---Annual Peak Flow Rates--- Flow Frequency Analysis Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0 . 119 3 2/09/01 2 :00 0 . 245 1 100 .00 0. 990 0 .068 8 1/05/02 16 :00 0. 154 2 25 .00 0 .960 0 . 154 2 2/27/03 7 : 00 0 . 119 3 10 .00 0 .900 0 .080 7 8/26/04 2 : 00 0. 116 4 5 .00 0 .800 0 . 095 5 10/28/04 16 :00 0 .095 5 3 .00 0.667 0.086 6 1/18/06 16 :00 0 .086 6 2 .00 0 . 500 0 . 116 4 10/26/06 0 : 00 0.080 7 1 . 30 0 .231 0 . 245 1 1/09/08 6 :00 0.068 8 1 . 10 0 . 091 Computed Peaks 0. 215 50 .00 0 . 980 41 I ► G, I I PROPOSED CONDITIONS ) DRIVEWAY DROP W/O LANDSCAPE STRIP - MATCH EX. DRIVEWAY WIDTH - 2 LOCATIONS POUR BACK TO EX. CONCRETE DRIVEWAY ) 16' DRIVEWAY DROP W/LANDSCAPE STRIP - 6 LOCATIONS I \\\�\\\\\\ / , 1 ) 16' DRIVEWAY DROP W/O LANDSCAPE STRIP - 3 LOCATIONS I ����\��� l > -. N00.30'33•E I >,-, I I • •• K -�I 3 V 276 7' .30' FOUND CONCRETE MON IN CASE WITH I lr•Firunirlirkiracr-anzr- 274 " h1 1 2 BRASS DISK AND PUNCH AT O , wINTERSECTION OF N.E. 14TH ANO k �� B MONTEREY AVE. N.E. N.,0 •+ s o DOWN 0.6' 2 N 187048.36 1 2:1 � E 1304459.92 I 1 * t i I EL 283.09 1 9 * . 272 y 8/16/2011 1 N,0‘ 8 ` STA. 0+00 0' „• • ti \ _27s ROCKERY DRAIN `V DRIVEWAY EXTENSION. �- ` : ,• . ' .-�_ - CONNECTION ROCKERY DRAIN r REuovE Excess /(TYP,) CONNECTION \--4,‘:.,1' , ASPHALT 1 STA. 4+00.0 9.42'1 ._._ 6 Me.) HC I • CB1, TYPE-1 �,0� cjl':'RIM=266.14ROCKERY DRAIN I 268 �0� ci: w UNE IE-263.14, 12" I - _ D" IE=263.64, 6" I --- i I.;; N MONTEREY--AVS_ E-----�'_ '"` `` ai- -- DOWNSPOUT CONNN PLUS CONNECTION I PERE, PEIj1. PERF. PIPE 2+00 I 3+00 414161411%/6 I,= Ail u— i , R=200.0' 40 �� tir ,e - � � 6 RIGIDI Z ..„. .. PVC ,� pi- :....- -, ©—— a. 4 © ,:: 4 .� 1p` '� iES i Vic: \ �. GUTTER & SIDEWALK 2015. 12" N-12 LF 12'- _ s�'C'.J n N « GRIND AND 2.OVERLAY I ''0 RT. SIDE O PLAT 0 -1Li i- M i2 OSr S+OO �� 24LF. 12" N-12 4 TO PUT BOUNDARY I ' 1; BOUNDARY 4.78 01 ,_ _ I:1 �� OS=3.33X &&Ef55. SIDETµCURe/GlJT1ER s N� I; * 2 ,;51LF._. �'� •:MONTEREY AVENUI Z -4- n> i.ALONG I DRIVEWAY �' L4 - _..STA. 4+00.0 9.42'• \., © d Ic"6 m "� REMOVE EXCESS ---- - : 2, TYPE/-. STA. 5+06.0 9.42'RT. 'c:° v I 00. u ASPHALT I RIMt2661i-26 C8'3, TYPE-1 1 4 DELTA i1- • ' IE=79?94 CB 4, TYPE-IL0, INT'X MOlk 2262 RIM=261.47 J2)\ I I'" IE=257.97, 12" RIM=259.60 60 HP STA.=5+8 IE=256.60,-t2" STA.=4+5 I \ — I, IE=256,10 1,vp,vi/ 2 SS--- SS a ----=�5 \I: - c 91: W - e'o. i l EE-12111.Yr �---\,7-0• /\- -u- 9E ABANDONED-Kr PLACE u — 0•4°W-RE(-AVEVE NC. ! _ , • STA 5+1C - ....iv G.4t. :.----....z.Olt #= `r� e��� = 7R�•�±tlrM► 00get�1.fSOIMO 'ilk° �.. 0 • RM72555 � N00'30'36"E__ -- 271.31' -4015:, 12" N-12 OS-5.70X H 30' �,1 , 1E...253.88/JUST TO FINAL GRADE ' / STA. 5+09.0, 32.0'RT. CB 6, TYPE-1 ** — FULL INFILTRATION FLOW CONTROL BMP'S ARE REQUIRED W/OUD LOCKING UD L 1ti. \Ex. CB- UTILIZING SEVERAL OPTIONS SEE SHEET 5 FOR TWO OPTIONS. RIM=256.60 RIM=255.4; SEE STORM WATER NOTES (2). IE=253.82, 12" 1E-253 60, IE=253.60, L DEVELOPED CONDITIONS {{b .. ,-......-... �J Q Lard Use taa+ ; Area Till Forest 0.00 acres' Till Pasture 0.00 acres Till Grass 0.00 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass 0.61 acres Wetland 0.00 acres Impervious 0.37 acres -Total ---- 1 0.98 acres Scale Factor : 1.00 Hourly Reduced Time Series: Developed Nelson »I Compute Time Series Modify User Input File for computed Time Series [.TSF] C 17' ;:Help /Files.KCRTS .___ , ----„ -0,.,--„,`' i Flow Frequency Analysis Time Series File:developed nelson.tsf Project Location:Sea-Tac d-' ---Annual Peak Flow Rates--- - Flow Frequency Analysis Flow Rate Rank Time of Peak - Peaks - Rank Return Prob (CFS) (CFS) . Period 0 . 109 5 2/09/01 2 :00 0. 219 1 100 . 00 0 .990 0 .079 8 1/05/02 16 :00 0 . 135 2 25.00 0 .960 0 . 135 2 2/27/03 7 :00 0 . 134 3 10.00 0 .900 0 .092 7 8/26/04 2 :00 0. 109 4 5.00 0 . 800 0 . 109 4 10/28/04 16 :00 0. 109 5 3.00 0 .667 0.098 6 1/18/06 16 :00 0.098 6 2.00 0 .500 0. 134 3 10/26/06 0:00 0.092 7 1 . 30 0.231 0.219 1 1/09/08 6 :00 0.079 8 1 .10 0.091 Computed Peaks 0 . 191 50. 00 0 .980 41 I k r 3 — Conveyance/ backwater analysis STORMWATER CONVEYANCE BACKWATER CALCULATION SHEET (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Barrel Entrance Entrance Pipe 100 year Pipe Outlet Inlet Barrel Barrel Velocity TW Friction HGL Head Segment Q Length Pipe "n" Elev Elev Area Velocity Head Elev Loss Elev Loss CB to CB (cfs) (ft) Size Value (feet) (feet) (sq. feet) (fps) (feet) (feet) (feet) (feet) (feet) ex.CB - #6 0.48 11 12" 0.012 253.60 253.82 0.79 0.61 0.01 254.31 0.0022 254.31 0.00 #6 - #4 0.48 40 12" 0.012 253.82 256.10 0.79 0.61 0.01 254.42 0.008 254.43 0.00 #4 - #5 0.48 24 12" 0.012 256.10 257.40 0.79 0.61 0.01 256.70 0.0048 256.70 0.00 #4 - #3 0.48 51 12" 0.012 256.10 257.97 0.79 0.61 0.01 258.00 0.008 258.01 0.00 #3 - #2 0.48 104 12" 0.012 257.97 262.94 0.79 0.61 0.01 258.57 0.0048 258.57 0.00 #2 -#1 0.48 20 12" 0.012 262.94 263.14 0.79 0.61 0.01 263.54 0.000 263.54 0.00 (14) (15) (16) (17) (18) (19) (20) (21) Exit Outlet Inlet Approach Bend Junction Head Control Control Velocity Head Head HW RIM ELEV Loss Elev Elev Head Loss Loss Elev UPSTREAM (feet) (feet) (feet) (feet) (feet) (feet) (feet) CB 0.01 254.33 254.42 0 0 0 254.42 256.60 OK.! 0.01 254.44 256.70 0 0 0 256.70 259.60 OK/ 0.01 256.72 258.00 0 0 0 258.00 260.40 OK.! 0.01 258.02 258.57 0 0 0 258.57 261.47 OK.! 0.01 258.59 263.54 0 0 0 263.54 266.14 OK.! 0.01 263.55 263.74 0 0 0 263.74 266.14 OK.! CONVeYA t G C ? �' ' " J x1 2iArea Till Forest 0.00 acres Till Pasture 0.00 acres Till Grass 0.00 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass 0.61 acres Wetland 0.00 acres Impervious 0.37 acres 09E0Total -- -- 0.98 acres Scale Factor : 1.00 15-Min Reduced it Flow Paths Time Series: Conveyance Check Nelson >>I Compute Time Series Modify User Input I File for computed Time Series (.TSF] j t Help/Hies-.t:£FiT5 . , i .,. p x 1 1 Flow Frequency Analysis Time Series File:conveyance check nelson. tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Frequency Analysis Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) Period �\J1 0. 176 6 8/27/01 18 :00 0 . 483 1 100 . 00 0 .990 1E: 0. 123 8 9/17/02 17 :45 . . 2 25 . 00 0 .960 0 . 341 2 12/08/02 17 :15 0 . 239 3 10 .00 0.900 • 0 . 142 7 8/23/04 14 :30 0. 197 4 5 .00 0.800 `0() 0 . 187 5 10/28/04 16 :00 0. 187 5 3 .00 0 .667 0 . 197 4 10/27/05 10 :45 0. 176 6 2 . 00 0 . 500 0 . 239 3 10/25/06 22 :45 0 . 142 7 1 . 30 0 .231 ' . i / i 0 . 483 1 1/09/08 6 : 30 0. 123 8 1 . 10 0.091 Computed Peaks 0 .435 50. 00 0.980 :4i 1 I. L. r• 4.3.1 CULVERTS—METHODS OF ANALYSIS I FIGURE 4.3.1.B HEADWATER DEPTH FOR SMOOTH INTERIOR PIPE CULVERTS WITH INLET CONTROL —180 -10,000 - - —168 —8,000 EXAMPLE (1) (2) (3) ENTRANCE TYPE -156 -6,000 D=42 Inches (3.0 feet). - 6. - - 13=120 els SQUARE EDGE WITH .-144 -5,000 - 5' - HEADWALL -4,000 HW HW -132 - T _ _(feet) 4. g, -3,000 (1) 2.5 e.8 — 5. 120 (2) 2.1 7.4 - - - I I - -2,000 (3) 2.2 7.7 4. .. - I I -108 - - 3 Jiawnaagan/ 'D in feet _ - -96 -1,000 _ PLAN (1) GROOVE END WITH - -800 -y _-_y � HEADWALL —84 - /��-- - 2. - 2_ -600 -500 : _ I _. I - 2. -72 —aoo o - - - i i —N.- -300 �(pj/ _ - - 1.5 - 1.5 I U U) : / - Z —60 V -200 w — 1.5 - - PLAN (2) Z - / 1-- - GROOVE END -54 E . - - PROJECTING W _� /W _100 0 - - a\�I J / ET —80 _ - / V �2 V -60 I- — 1.0 _ 1.0 ' // O LU U. S0 HW SCALE ENTRANCE G _ 1.0 - _ // ' -40 D TYPE re FW- —36 —30 (1) Square edge with I- — .9 - .9 %7 (3) —33 - headwall — '9 - et EI 7 Q _20 (2) Groove end with W - —30 - headwall 2 — •8 — .8 (3) Groove end '8 —27 _ projecting - .. - -10 — —24 _8 — .7 -6 To use scale (2) or(3) project - - 21 •-5 horizontally to scale (1), then - —4 use straight Inclined line through D and 0 scales, or reverse as / \ — .6 — .6 _3 illustrated. _ 6 -18 = 111.111 -2S - - -15 - \/ 1.0 1 o. i1, �/ rV L 2 � I .46 2009 Surface Water Design Manual 1/9/2009 4-45 4.3.1 CULVERTS—METHODS OF ANALYSIS I FIGURE 4.3.1.F CRITICAL DEPTH OF FLOW FOR CIRCULAR CULVERTS — 120 .3,000 — 114 —0.99 _ — 108 =2,000 — 102 = - - 96 =1,000 — 90 - — — � _ =0.90 500 _ — 78 400 I -0.80 —72 300 - •6 =200 —0.70 —60 = 00 —0.60 — 54 - . w = —48 a 50 - o 40 0 _ 0.50 O co L. 30 � _ —42 0 -20 0 _ ' �C j� w - w - ° = 0.40 �_ lil — 36 = _ O• - 33 - Q2T =1.• - 0• � 1 Flo — 30 r 5 gA3 C D —0.30 4 — 27 I- v - CL>"CD•49 CI Pr) dc —24 =2 + — f _ — 0•II T - — 21 - - 1 Note: For all cross-sectional - shapes, do can be calculated by —0.20 —18 trial and error knowing that the J quantity(Q2T/gA3)=1.0 at critical depth. —15 1 EXAMPLE \. D = 66 inches, Q = 100cfs do/D - Ratio =0.50 12 do= (0.50)(66 inches)=33 inches±(12 inches/ft) dc=2.75 feet I 2009 Surface Water Design Manual 1/9/2009 4-49 SECTION 4.2 PIPES,OUTFALLS,AND PUMPS FIGURE 4.2.1.F NOMOGRAPH FOR SIZING CIRCULAR DRAINS FLOWING FULL -1,000 - -900 - -800 .0001 - -700 -2.0 -600 .0002 - 500Minimum _ 0003 Allowable - =400 .0004 .0001 - .0005 Velocity .0006 (Flowing -3.0 -300 -120 .0008 .0002 Full) _ N .001 -108 a .0003 - = o - .0004 200 =88 � .002 .0005 -4.0 -84- -78 c4 .0006 - - -72 0 .003 .0008 _ -66 .004 .001 100 -60 0006 0 _5.0 .005 - _90 -54 www .008 .002 o 0 = -80 -48 01 0 / V -6.0 -70 w .003 c w = _ -60 U- 42 .004 w = 7.0 .02 _ .005 O - 0 _50 -36 uz -33 .03 .008 aw. w -8.0 =40 -30 w .04 .010 O w - Lu r a -27 cn u_ -9.0 1� < -30 ET_ 24 .008 .020 Z -10.0 _ = O -21 .10 co .7. Z..3.030 v E =20 -18040 O - w - w w _ 2 -15 .060 - a _ - o .080 - -12 .100 --10 -10 - 9 SAMPLE USE -8 - _ -7 -8 24"dia.CMP @ 2%slope yields -20.0 -6 17cfs @ 5.4 fps velocity = 5 -6 (n=0.024) _ =4 Values per Manning's equation = = Q=(1.49 ) AR2/3 S 1/2 - _3 n -30.0 z. This table can be converted - to other"n"values by applying - -2 formula: _ -40.0 - Q1 = n2 Q2 n1 -1 1/9/2009 2009 Surface Water Design Manual 4-22 B — PROPOSED BMP's C.2.2 FULL INFILTRATION I FIGURE C.2.2.0 TYPICAL DRYWELL INFILTRATION SYSTEM Roof Downspout House Catch Basin (Yard Drain) / / --f/ Roof flow Downspout O DRY WELL 48 Inch Diameter Hole Filled with PLAN VIEW 11/2-3"Washed Drain Rock NTS Roof Downspout Mark Center of Hole with 1"House Overflow or Other mpepaensPVC I , Splash Block Topsoil Flush with Surface 1'min. Fine Mesh Screen Min.4"dia. ‘o }.�k.• ;�%og! PVC Pipe �NIDXa• ' •�' pio Catch Basin oo (Yard Drain) 'k,' Varies i�. 48 Inch Diameter g- Sides of Hole 4 Hole Filled with ]; Lined with .g� 11/2-3"Washed Filter Fabric Drain Rock 15'min. �! Min. 1'above Seasonal DRY WELL High Groundwater Table SECTION NTS 2009 Surface Water Design Manual—Appendix C 1/9/2009 I C-47 7- DRY - WELL INFILTRATION DETAIL C.2.11 PERFORATED PIPE CONNECTION ❑ TEXT OF INSTRUCTIONS Your property contains a stormwater management flow control BMP(best management practice)called a "perforated pipe connection,"which was installed to reduce the stormwater runoff Impacts of some or all of the impervious surface on your property. A perforated pipe connection is a length of drainage conveyance pipe with holes in the bottom,designed to"leak"runoff,conveyed by the pipe, into a gravel filled trench where It can be soaked Into the surrounding soil. The connection Is Intended to provide opportunity for infiltration of any runoff that is being conveyed from an impervious surface(usually a roof)to a local drainage system such as a ditch or roadway pipe system. The size and composition of the perforated pipe connection as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. The soil overtop of the perforated portion of the system must not be compacted or covered with impervious materials. IFIGURE C.2.11.A PERFORATED PIPE CONNECTION FOR A SINGLE FAMILY RESIDENCE random fill 6" \/\/\/\\\\/\/\/ 6" filter fabric 17° o o p . 0 6 pert pipe 18"min g17°ova o a°av° o° v ° a ° 1 /z" s/a"washed rock aoa oDDa°C°Coo 09 ° v0 °vO4 O ° O a a D n 1 F. h 24" min--.II TRENCH X-SECTION NTS slope to road drainage system 2'X10' level trench wiped pipe PLAN VIEW OF ROOF NTS 2009 Surface Water Design Manual Appendix C 1M2009 C-81 PERF. PIPE CONNECTION BMP DETAIL C.2.2 FULL INFILTRATION IFIGURE C.2.2.A TYPICAL TRENCH INFILTRATION SYSTEM -roof drain PLAN VIEW NTS ,r—4"rigid or 6"flexible perforated pipe I J infiltration trench sump w/solid lid PLAN VIEW roof drain NTS overflow 4"rigid or 6"flexible splash block `� perforated pipe J 6" 6" y • i it, ° • / °Q� -—level --- d� !' 5EX 4 washed rock L j 4o Q o 00 " it �;in 5.0'min 12" ;' I 112"-3(4" '.--i -' 0* o p d: 1'min "me, °..SZ_9__A a °ter, finemeshCB sump w/solid lid Lvaries - A filter fabric i compacted backlill 6" 111111111.1r sy 4"rigid or 6'flexible °°o• ► .70' perforated pipe 24" .°p o�Q°p • a p4• o 0 12 "1l v° op V G pv , washed rock p o o °Clop 1 t/2"-3/4" • o o�p ° a Imo—24" SECTION A NTS 2009 Surface Water Design Manual-Appendix C 1/9/2009 C-45 I INFILTRATI ❑ N TRE \ CH DETAIL C - MAINTENANCE APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60%of the depth from the Sump of catch basin contains no bottom of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than 1/2 cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Comer of frame extends more than%inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than%inch. Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab. separation of more than%inch of the frame from the top slab. Cracks in walls or Cracks wider than%inch and longer than 3 feet, Catch basin is sealed and bottom any evidence of soil particles entering catch structurally sound. basin through cracks,or maintenance person judges that catch basin is unsound. Cracks wider than 1/2 inch and longer than 1 foot No cracks more than 1/4 inch wide at at the joint of any inlet/outlet pipe or any evidence the joint of inlet/outlet pipe. of soil particles entering catch basin through cracks. Settlement/ Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than%-inch at the joint of the No cracks more than%-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the catch basin at the joint of the inlet/outlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than'/-inch at the joint of the No cracks more than'%-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 1 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-9 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Metal Grates Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design (Catch Basins) standards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design Any open structure requires urgent standards. maintenance. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Botts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and Remove cover/lid after applying 80 lbs.of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual—Appendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 6 -CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20%of the diameter of the pipe. Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes. water through pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective Protective coating is damaged;rust or corrosion Pipe repaired or replaced. coating or corrosion is weakening the structural integrity of any part of pipe. Damaged Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%or is determined to have weakened structural integrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris Geared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all sediment accumulation design depth. and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards. place or missing(If area 5 square feet or more,any exposed native Applicable) soil. 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-11 RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY RENTON,WA 98057 DECLARATION OF COVENANT FOR MAINTENANCE AND INSPECTION OF FLOW CONTROL BMPS Grantor: Grantee: City of Renton Legal Description: Additional Legal(s)on: Assessor's Tax Parcel ID#: IN CONSIDERATION of the approved City of Renton(check one of the following)❑ residential building permit, ❑ commercial building permit, ❑ clearing and grading permit, ❑ subdivision permit,or ❑ short subdivision permit for Application File No.LUA/SWP relating to the real property("Property")described above,the Grantor(s),the owner(s)in fee of that Property,hereby L covenants(covenant)with City or Renton, a political subdivision of the state of Washington,that he/she(they)will observe,consent to,and abide by the conditions and obligations set forth and described in Paragraphs 1 through 8 below with regard to the Property. Grantor(s)hereby grants(grant), covenants(covenant),and agrees(agree)as follows: 1. Grantor(s)or his/her(their)successors in interest and assigns("Owners")shall retain, uphold, and protect the stormwater management devices,features,pathways, limits,and restrictions,known as flow control best management practices("BMPs"),shown on the approved Flow Control BMP Site Plan for the Property attached hereto and incorporated herein as Exhibit A. 2. The Owners shall at their own cost,operate,maintain,and keep in good repair,the Property's BMPs as described in the approved Design and Maintenance Details for each BMP attached hereto and incorporated herein as Exhibit B. 3. City or Renton shall provide at least 30 days written notice to the Owners that entry on the Property is planned for the inspection of the BMPs. After the 30 days,the Owners shall allow the City of Renton to enter for the sole purpose of inspecting the BMPs. In lieu of inspection by the City,the Owners may elect to engage a licensed civil engineer registered in the state of Washington who has expertise in drainage to inspect the BMPs and provide a written report describing their condition. If the engineer option is chosen,the Owners shall provide written notice to the City of Renton within fifteen days of receiving the City's notice of inspection. Within 30 days of giving this notice,the Owners,or the engineer on behalf of the Owners, shall provide the engineer's report to the City of Renton. If the report is not provided in a timely manner as specified above,the County may inspect the BMPs without further notice. 4. If the City determines from its inspection,or from an engineer's report provided in accordance with Paragraph 3,that maintenance,repair,restoration,and/or mitigation work is required for the BMPs, The City shall notify the Owners of the specific maintenance,repair,restoration,and/or mitigation work (Work)required under RMC 4-6-030. The City shall also set a reasonable deadline for completing the Work or providing an engineer's report that verifies completion of the Work. After the deadline has passed,the Owners shall allow the City access to re-inspect the BMPs unless an engineer's report has been provided verifying completion of the Work. If the work is not completed properly within the time frame set by the City,the City may initiate an enforcement action. Failure to properly maintain the BMPs is a violation of RMC 4-6-030 and may subject the Owners to enforcement under the RMC 1-3, including fines and penalties. 5. Apart from performing routine landscape maintenance,the Owners are hereby required to obtain written approval from the City or Renton before performing any alterations or modifications to the BMPs. 6. Any notice or approval required to be given by one party to the other under the provisions of this Declaration of Covenant shall be effective upon personal delivery to the other party, or after three(3) days from the date that the notice or approval is mailed with delivery confirmation to the current address on record with each Party. The parties shall notify each other of any change to their addresses. 7. This Declaration of Covenant is intended to promote the efficient and effective management of surface water drainage on the Property,and it shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s')successors in interest and assigns. 8. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City of Renton that is recorded by King County in its real property records. r IN WITNESS WHEREOF,this Declaration of Covenant for the Maintenance and Inspection of Flow Control BMPs is executed this day of ,20 GRANTOR, owner of the Property GRANTOR, owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me known to be the individual(s)described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed,for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 New Printed name Notary Public in and for the State of Washington, residing at My appointment expires C.2.2.4 USE OF DRYWELLS FOR FULL INFILTRATION Drywells are gravel filled holes as opposed to trenches and therefore may allow for a more compact design in areas where the depth to the maximum wet-season water table is relatively deep (e.g., 6 feet or greater). Figure C.2.2.0 on page C-47 illustrates the specifications for drywell infiltration systems as outlined below: 1. When located in coarse sands and cobbles, drywells must contain a volume of gravel equal to or greater than 60 cubic feet per 1,000 square feet of impervious surface served. When located in medium sands, drywells must contain at least 90 cubic feet of gravel per 1,000 square feet of impervious surface served. 2. Drywells must be at least 48 inches in diameter and deep enough to contain the gravel amounts specified above for the soil type and impervious surface area served. 3. The gravel used for drywells must be 11/2-inch to 3-inch washed drain rock. The drain rock may be covered with backfill material as shown in Figure C.2.2.0 (p. C-47) or remain exposed at least 6 inches below the lowest surrounding ground surface. 4. Filter fabric (geotextile) must be placed on top of the drain rock (if proposed to be covered with backfill material) and on the drywell sides prior to filling with the drain rock. 5. Spacing between drywells shall be a minimum of 10 feet. 6. Drywells must be setback at least 15 feet from buildings with crawl space or basement elevations that are below the overflow point of the drywell. C.2.2.5 USE OF GROUND SURFACE DEPRESSIONS FOR FULL INFILTRATION Ground surface depressions (also called "infiltration depressions") are another option for full infiltration SECTION C.2 FLOW CONTROL BMPs other types of soils or fill materials if designed by a civil engineer in accordance with the infiltration facility standards in Section 5.4 of the SWDM. b) For purposes of determining whether full infiltration of roof runoff is mandatory as outlined in Section C.l.3,the depth of soil to the maximum wet season water table or hardpan must be at least 3 feet. For any optional or mandatory application of full infiltration,the depth of soil to the maximum wet season water table or hardpan must be at least 1 foot below the bottom of a gravel filled infiltration system and at least 3 feet below the bottom of ground surface depression used for full infiltration. 2. For purposes of determining whether full infiltration of roof runoff is mandatory as outlined in Section C.1.3,one of the following infiltration devices must be used in accordance with the design specifications for each device set forth in Sections C.2.2.3,C.2.2.4,and C.2.2.5. Note:full infiltration may be possible using other types and sizes of infiltration devices if designed by a civil engineer in accordance with the infiltration.facility standards in Section 5.4 of the SWDM. • Gravel filled trenches(see Section C.2.2.3,p.C-42) • Drywells(see Section C.2.2.4,p.C-43) • Ground surface depressions(see Section C.2.2.5,p.0-43) 3. A minimum 5-foot setback shall be maintained between any part of an infiltration device and any structure or property line. Larger setbacks from structures may be specified in the design specifications for each infiltration device. Infiltration devices may not be placed in sensitive area buffers. A 50-foot setback is required between an infiltration device and a steep slope hazard area or landslide hazard area(this may be reduced if approved by a geotechnical engineer or engineering geologist and DDES). 4. Infiltration devices are not allowed in critical area buffers or on slopes steeper than 25%(4 horizontal to 1 vertical). Infiltration devices proposed on slopes steeper than 15%or within 50 feet of a landslide hazard area or steep slope hazard area must be approved by a geotechnical engineer or engineering geologist unless otherwise approved by the DDES staff geologist. 5. For sites with septic systems, infiltration devices must be located downgradient of the primary and reserve drainfield areas. DDES permit review staff can waive this requirement if site topography clearly prohibits subsurface flows from intersecting the drainfield. 6. The infiltration of runoff must not create flooding or erosion impacts as determined by DDES. If runoff is infiltrated near a landslide hazard area,erosion hazard area,steep slope hazard area,or a slope steeper than 15%,DDES may require evaluation and approval of the proposal by a geotechnical engineer or engineering geologist. C.2.2.3 USE OF GRAVEL FILLED TRENCHES FOR FULL INFILTRATION Gravel filled trenches(also called"infiltration trenches")are a good option where the depth to the maximum wet-season water table or hardpan is between 3 and 6 feet. Figure C.2.2.A(p.C-45)and Figure C.2.2.B(p.C-46)illustrate the specifications for gravel filled trench systems as outlined below: 1. When located in coarse sands or cobbles,infiltration trenches must be at least 20 feet in length per 1,000 square feet of impervious surface served. When located in medium sands,infiltration trenches must be at least 30 feet in length per 1,000 square feet of impervious surface served. 2. Maximum trench length must not exceed 100 feet from the inlet sump. 3. The trench width must be a minimum of 2 feet. 4. The trench must be filled with at least 18 inches of 3/4-inch to 1'/2-inch washed drain rock. The drain rock may be covered with backfill material as shown in Figure C.2.2.A or remain exposed at least 6 inches below the lowest surrounding ground surface as shown in Figure C.2.2.B. 1/9/2009 2009 Surface Water Design Manual—Appendix C C-42 SECTION C.2 FLOW CONTROL BMPs 3. The depression overflow point must be at least 6 inches below any adjacent pavement area and must be situated so that overflow does not cause erosion damage or unplanned inundation. 4. The depression side slopes must be no steeper than 3 horizontal to 1 vertical. 5. Spacing between multiple infiltration depressions shall be a minimum of 4 feet. 6. Infiltration depressions must be setback at least 15 feet from buildings with crawl space or basement elevations that are below the overflow point of the infiltration depression. 7. Infiltration depressions may be any size or shape provided the above specifications and the minimum requirements in Section C.2.2.1 are met. 8. The ground surface of the infiltration depression must be vegetated with grass or other dense ground cover. C.2.2.6 MAINTENANCE INSTRUCTIONS FOR FULL INFILTRATION If the full infiltration flow control BMP is proposed for a project,the following maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.3 (p. C-18). The intent of these instructions is to explain to future property owners,the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum;DDES may require additional instructions based on site- specific conditions. Also,as the County gains more experience with the maintenance and operation of these BMPs,future updates to the instructions will be posted on King County's Surface Water Design Manual website. ❑ TEXT OF INSTRUCTIONS Your property contains a stormwater management flow control BMP (best management practice)called luit "full infiltration,"which was installed to mitigate the stormwater quantity and quality impacts of some or all ` of the impervious surfaces on your property. Full infiltration is a method of soaking runoff from impervious area(such as paved areas and roofs) into the ground. If properly installed and maintained,full infiltration can manage runoff so that a majority of precipitation events are absorbed. Infiltration devices, such as gravel filled trenches, drywells, and ground surface depressions,facilitate this process by putting runoff in direct contact with the soil and holding the runoff long enough to soak most of it into the ground. To be successful,the soil condition around the infiltration device must be reliably able to soak water into the ground for a reasonable number of years. The infiltration devices used on your property include the following as indicated on the flow control BMP site plan: ❑ gravel filled trenches, ❑ drywells, ❑ ground surface depressions. The size, placement, and composition of these devices as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. Infiltration devices must be inspected annually and after major storm events to identify and repair any physical defects. Maintenance and operation of the system should focus on ensuring the system's viability by preventing sediment-laden flows from entering the device. Excessive sedimentation will result in a plugged or non-functioning facility. If the infiltration device has a catch basin, sediment accumulation must be removed on a yearly basis or more frequently if necessary. Prolonged ponding around or atop a device may indicate a plugged facility. If the device becomes plugged, it must be replaced. Keeping the areas that drain to infiltration devices well swept and clean will enhance the longevity of these devices. For roofs, frequent cleaning of gutters will reduce sediment loads to these devices. 1/9/2009 2009 Surface Water Design Manual—Appendix C C-44 D - BOND QUANTITY WORKSHEET Site Improvement Bond Quantity Worksheet Original bond computations reL—;doName: 4VA d 11 -o V b Date: i(1(f,'� ea , rZQ 12_PE Registration Number: �i�4 ro 0 -_ Tel.#: �-?S •ZeO ••2A-12— 412FiFirm rm Name: O la Address: W7 _- QL�� Project No: f ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND*,** PUBLIC ROAD&DRAINAGE AMOUNT MAINTENANCE/DEFECT BOND'," Stabilization/Erosion Sediment Control(ESC) (A) $ \1/ - Existing Right-of-Way Improvements (B) $ 7,G Future Public Road Improvements&Drainage Facilities (C) $ 1t-2' Private Improvements (D) $ i gco - Construction Bond*Amount (A+B+C+D) = TOTAL (1) $ 14 ` C./ Minimum bond'amount is$1000. Maintenance/Defect Bond'Total 0.20= $ NAME OF PERSON PREPARING BOND'REDUCTION: Date: 'NOTE: The word"bond"as used in this document means any financial guarantee acceptable to the City of Renton. **NOTE:All prices include labor,equipment,materials,overhead and profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY RDSD Page 1 of 1 Unit prices updated:2/12/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet Existing Future Public Private Quantity Completed Right-of-Way Road Improvements Improvements (Bond Reduction)* &Drainage Facilities Quant. Unit Price ' Unit Quant. I Cost Quant. Cost Quant. 1 Cost Complete Cost GENERAL ITEMS No. Backfill&Compaction-embankment GI-1 $ 5.62 CY 0.00 0.00 0.00 0.00 Backfill&Compaction-trench GI-2 $ 8.53 CY 0.00 0.00 0.00 0.00 Clear/Remove Brush,by hand GI-3 $ 0.36 SY 0.00 0.00 0.00 0.00 Clearing/Grubbing/Tree Removal GI-4 $8,876.16 Acre 0.00 0.00 0.00 0.00 Excavation-bulk GI-5 $ 1.50 CY 0.00 r,j'2 '7 j 0.00 I U2 R` 0.00 0.00 Excavation-Trench GI-6 $ 4.06 CY 0.00 0.00 0.00 0.00 Fencing,cedar,6'high GI-7 $ 18.55 LF 0.00 0.00 0.00 0.00 Fencing,chain link,vinyl coated, 6'high GI-8 $ 13.44 LF 0.00 0.00 0.00 0.00 Fencing,chain link,gate,vinyl coated, 2( GI-9 $ 1.271.81 Each 0.00 0.00 0.00 0.00 Fencing,split rail,3'high GI-10 $ 12.12 LF 0.00 0.00 0.00 0.00 Fill&compact-common barrow GI-11 $ 22.57 CY 0.00 0.00 0.00 0.00 Fill&compact-gravel base GI-12 $ 25.48 CY 0.00 0.00 0.00 0.00 Fill&compact-screened topsoil GI-13 $ 37.85 CY 0.00 0.00 0.00 0.00 Gabion, 12"deep,stone filled mesh GI-14 $ 54.31 SY 0.00 0.00 0.00 0.00 Gabion, 18"deep,stone filled mesh GI-15 $ 74.85 SY 0.00 0.00 0.00 0.00 Gabion,36"deep,stone filled mesh GI-16 $ 132.48 SY 0.00 0.00 0.00 0.00 Grading,fine,by hand GI-17 $ 2.02 SY 0.00 0.00 0.00 0.00 Grading,fine,with grader GI-18 $ 0.95 SY 0.00 7if) .-2 0.00 C(t �/�� 0.00 0.00 Monuments,3'long GI-19 $ 135.13 Each 0.00 an 0.00 0.00 0.00 Sensitive Areas Sign GI-20 $ 2.88 Each 0.00 0.00 0.00 0.00 Sodding, 1"deep,sloped ground GI-21 $ 7.46 SY 0.00 0.00 r 0.00 0.00 Surveying,line&grade GI-22 $ 788.26 Day 0.00 0.00 Li- � �1 �/% 0.00 0.00 Surveying,lot location/lines GI-23 $ 1,556.64 Acre 0.00 0.00 ,-j977 J'.t9 „.-}e7-77 l 0.00 0.00 Traffic control crew(2 flaggers) GI-24 $ 85.18 HR 0.00 0.00 0.00 0.00 Trail,4"chipped wood GI-25 $ 7.59 SY 0.00 0.00 0.00 0.00 Trail,4"crushed cinder GI-26 $ 8.33 SY 0.00 0.00 0.00 0.00 Trail,4"top course GI-27 $ 8.19 SY 0.00 0.00 0.00 0.00 Wall,retaining,concrete GI-28 $ 44.16 SF 0.00 0.00 0.00 0.00 'Wall,rockery Cl-29 $ 9.49 SF 0.00 0.00 MU, 4;1(10.00 rl`� .00 0.00 Page 2 of 7 SUBTOTAL 0.00 0.00 0.00 0.00 Unit prices updated: 2112/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit ' Quant. I Cost Quant.J Cost Quant. I Cost Complete Cost ROAD IMPROVEMENT No. AC Grinding,4'wide machine<1000sy RI-1 $ 23.00 SY 0.00 0.00 0.00 0.00 AC Grinding,4'wide machine 1000-2000 RI-2 $ 5.75 SY 0.00 0.00 0.00 0.00 AC Grinding,4'wide machine>2000sy RI-3 $ 1.38 SY 0.00 0.00 0.00 0.00 AC Removal/Disposal/Repair RI-4 $ 41.14 SY (20 ,k - 1 0.00 0.00 0.00 0.00 Barricade,type I RI-5 $ 30.03 LF / 0.00 0.00 0.00 0.00 Barricade,type III(Permanent) RI-6 $ 45.05 LF 0.00 0.00 0.00 0.00 Curb&Gutter,rolled RI-7 $ 13.27 LF 0.00 `0.00 0.00 0.00 Curb&Gutter,vertical RI-8 $ 9.69 LF -IC70 7 0.00 J 47 0.00 0.00 0.00 Curb and Gutter,demolition and disposal RI-9 $ 13.58 LF ,` 0.00 0.00 0.00 0.00 Curb,extruded asphalt RI-10 $ 2.44 LF 0.00 0.00 0.00 0.00 Curb,extruded concrete RI-11 $ 2.56 LF �f� r`r r � 0.00 0.00 0.00 0.00 Sawcut,asphalt.3"depth RI-12 $ 1.85 LF /e f7 "1 p/2 0.00 0.00 0.00 0.00 Sawcut,concrete,per 1"depth RI-13 $ 1.69 LF 0.00 0.00 0.00 0.00 Sealant,asphalt RI-14 $ 0.99 LF 7c70 4A yG7g7 0.00 0.00 0.00 0.00 Shoulder,AC, (see AC road unit price) RI-15 $ - SY 0.00 0.00 0.00 0.00 Shoulder,gravel,4"thick RI-16 $ 7.53 SY 0.00 _,....., 0.00 0.00 0.00 Sidewalk,4"thick RI-17 $ 30.52 SY JR kv 0.00 te5 $t V 0.00 0.00 0.00 Sidewalk,4"thick,demolition and disposa RI-18 $ 27.73 SY 0.00 / 0.00 0.00 0.00 Sidewalk,5"thick RI-19 $ 34.94 SY 0.00 0.00 0.00 0.00 Sidewalk,5"thick,demolition and dispose RI-20 $ 34.65 SY 0.00 0.00 0.00 0.00 Sign,handicap RI-21 $ 85.28 Each 0.00 0.00 0.00 0.00 Striping,per stall RI-22 $ 5.82 Each 0.00 0.00 0.00 0.00 Striping,thermoplastic,(for crosswalk) RI-23 $ 2.38 SF 0.00 0.00 0.00 0.00 Striping,4"reflectorized line RI-24 $ 0.25 LF 0.00 0.00 0.00 0.00 Page 3 of 7 SUBTOTAL 0.00 0.00 0.00 0.00 Coe Unit prices updated:2/12/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. Unit Price Unit Quant. I Cost Quanta Cost Quant. I Cost Complete Cost ROAD SURFACING (4"Rock=2.5 base&1.5"too course) For'93 KQRS(6.5"Rock=5"base&1.L'too course) For KCRS'93,(additional 2.5"base)add:RS-1 $ 3.60 SY 0.00 0.00 0.00 0.00 AC Overlay, 1.5"AC RS-2 $ 7.39 SY 0.00 0.00 0.00 0.00 AC Overlay,2"AC RS-3 $ 8.75 SYK_ ,�. 0.00 0.00 0.00 0.00 AC Road,2",4"rock, First 2500 SY RS-4 $ 17.24 SY Vi '�f� 0.00-rip *`y ct 0.00 0.00 0.00 AC Road.2",4"rock.Qty.over 2500SY RS-5 $ 13.36 SY 0.00 0.00 0.00 0.00 AC Road.3",4"rock, First 2500 SY RS-6 $ 19.69 SY 0.00 0.00 0.00 0.00 AC Road,3",4"rock,Qty.over 2500 SY RS-7 $ 15.81 SY 0.00 0.00 0.00 0.00 AC Road,5",First 2500 SY RS-8 $ 14.57 SY 0.00 0.00 0.00 0.00 AC Road.5",Qty.Over 2500 SY RS-9 $ 13.94 SY 0.00 0.00 0.00 0.00 AC Road,6", First 2500 SY RS-1C $ 16.76 SY 0.00 0.00 0.00 0.00 AC Road,6",Qty.Over 2500 SY S-1' $ 16.12 SY 0.00 0.00 0.00 0.00 Asphalt Treated Base,4"thick RS-1'4 $ 9.21 SY 0.00 0.00 0.00 0.00 Gravel Road,4"rock, First 2500 SY IRS-1C $ 11.41 SY 0.00 0.00 0.00 0.00 Gravel Road,4"rock,Qty.over 2500 SY RS-1z $ 7.53 SY 0.00 0.00 0.00 0.00 PCC Road.5",no base,over 2500 SY RS-1t $ 21.51 SY 0.00 0.00 0.00 0.00 PCC Road, 6",no base,over 2500 SY RS-1E $ 21.87 SY 0.00 0.00 0.00 0.00 Thickened Edge �S-1i $ 6.89 LF 0.00 0.00 0.00 0.00 Page 4 of 7 SUBTOTAL 0.00 0.00 0.00 0.00 yi 10 41;4127 Unit prices updated:2112/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction' Right-of-way Road Improvements Improvements &Drainage Facilities Quant. 'Unit Price Unit Quant. 1 Cost Quant./ Cost Quant. I Cost Complete Cost DRAINAGE (CPP=Corruoated Plas is Pioe N12 or Eauiv lent) For Culvert prices, Average of 4'cover was assumed.Assume perforated PVC is same price as solid pipe. Access Road. R/D D-1 $ 16.74 SY 0.00 0.00 0.00 0.00 Bollards-fixed D-2 $ 240.74 Each 0.00 0.00 0.00 0.00 Bollards-removable D-3 $ 452.34 Each 0.00 0.00 0.00 0.00 '(CBs include frame and lid) CB Type I D-4 $1,257.64 Each - ( 119.7e, 0.00 7 A 0.00 0.00 0.00 CB Type IL D-5 $1,433.59 Each 0.00 0.00 0.00 0.00 CB Type II,48"diameter D-6 $2,033.57 Each' 0.00 0.00 0.00 0.00 for additional depth over 4' D-7 $ 436.52 FT 0.00 0.00 0.00 0.00 CB Type II,54"diameter D-8 $2,192.54 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D-9 $ 486.53 FT 0.00 0.00 0.00 0.00 CB Type II,60"diameter D-10 $2,351.52 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D-11 $ 536.54 FT 0.00 0.00 0.00 0.00 CB Type II,72"diameter D-12 $3,212.64 Each 0.00, 0.00 0.00 0.00 for additional depth over 4' D-13 $ 692.21 FT 0.00 0.00 0.00 0.00 Through-curb Inlet Framework(Add) D-14 $ 366.09 Each 0.00 0.00 0.00 0.00 Cleanout, PVC,4" D-15 $ 130.55 Each 0.00 0.00 0.00 0.00 Cleanout, PVC,6" D-16 $ 174.90 Each 0.00 0.00 0.00 0.00 Cleanout, PVC,8" D-17 $ 224.19 Each 0.00 0.00 0.00 0.00 Culvert, PVC,4" D-18 $ 8.64 LF 0.00 WIP I 0.00 0.00 0.00 Culvert, PVC,6" D-19 $ 12.60 LF 0.00 telt # vZfet!) 0.00 0.00 0.00 Culvert,PVC, 8" D-20 $ 13.33 LF 0.00 0.00 0.00 0.00 Culvert,PVC, 12" D-21 $ 21.77 LF CO grik \,"?( 0.00 z7 CW:15 0.00 0.00 0.00 Culvert.CMP,8" D-22 $ 17.25 LF 0.00 0.00 0.00 0.00 Culvert,CMP, 12" D-23 $ 26.45 LF 0.00 0.00 0.00 0.00 Culvert,CMP, 15" D-24 $ 32.73 LF 0.00 0.00 0.00 0.00 Culvert,CMP, 18" D-25 $ 37.74 LF 0.00 0.00 0.00 0.00 Culvert,CMP,24" D-26 $ 53.33 LF 0.00 _ 0.00 0.00 0.00 Culvert,CMP,30" D-27 $ 71.45 LF 0.00 0.00 0.00 0.00 Culvert,CMP,36" D-28 $ 112.11 LF 0.00 0.00 0.00 0.00 Culvert,CMP,48" D-29 $ 140.83 LF 0.00 0.00 0.00 0.00 Culvert,CMP,60" D-30 $ 235.45 LF 0.00 0.00 0.00 0.00 Culvert,CMP,72" D-31 $ 302.58 LF 0.00 0.00 0.00 0.00 Page 5 of 7 SUBTOTAL f t120)--,- 0.00 0.00 0.00 0.00 60 Unit prices updated: 2/12/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 r- r Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction* Right-of-way Road improvements Improvements DRAINAGE CONTINUED &Drainage Facilities Quant. No. Unit Price Unit Quant. I Cost Quant.I Cost Quant. I Cost Complete Cost Culvert,Concrete,8" 16-31 3 n.62 EF b 0 0 0 Culvert,Concrete, 12" D-33 $ 30.05 LF 0 0 0 0 Culvert,Concrete,15" D-34 $ 37.34 LF 0 0 0 0 Culvert,Concrete,18" D-35 $ 44.51 LF 0 0 0 0 Culvert,Concrete,24" D-36 $ 61.07 LF ' 0 0 0 0 Culvert,Concrete,30" D-37 $ 104.18 LF 0 0 0 0 Culvert,Concrete,36" D-38 $ 137.63 LF 0 0 0 0 Culvert,Concrete,42" D-39 $ 158.42 LF 0 0 0 0 Culvert,Concrete,48" D-40 $ 175.94 LF 0 0 0 0 Culvert,CPP,6" D-41 $ 10.70 LF 0 0 0 0 Culvert,CPP,8" D-42 $ 16.10 LF 0 0 0 0 Culvert,CPP, 12" D-43 $ 20.70 LF 0 0 0 0 Culvert,CPP, 15" D-44 $ 23.00 LF 0 0 0 0 Culvert,CPP, 18" D-45 $ 27.60 LF 0 0 0 0 Culvert,CPP,24" D-46 $ 36.80 LF 0 0 0 0 Culvert,CPP,30" D-47 $ 48.30 LF 0 0 0 0 Culvert,CPP,36" D-48 $ 55.20 LF 0 0 0 0 Ditching D-49 $ 8.08 CY 0 0 0 0 Flow Dispersal Trench (1,436 base+) D-50 $ 25.99 LF - French Drain (3'depth) D-51 $ 22.60 LF 0 0 0 0 Geotextile,laid in trench,polypropylene D-52 $ 2.40 SY 0 0 0 0 Infiltration pond testing D-53 $ 74.75 HR 0 0 0 0 Mid-tank Access Riser,48"dia, 6'deep D-54 $1,605.40 Each 0 0 0 0 Pond Overflow Spillway D-55 $ 14.01 SY 0 0 0 0 Restrictor/Oil Separator, 12" D-56 $1,045.19 Each 0 0 0 0 Restrictor/Oil Separator, 15" D-57 $1,095.56 Each 0 0 0 0 Restrictor/Oil Separator, 18" D-58 $1,146.16 Each 0 0 0 0 Riprap,placed D-59 $ 39.08 CY 0 0 0 0 Tank End Reducer(36"diameter) D-60 $1,000.50 Each 0 0 0 0 Trash Rack, 12" D-61 $ 211.97 Each 0 0 0 0 Trash Rack,15" D-62 $ 237.27 Each 0 0 0 0 Trash Rack, 18" D-63 $ 268.89 Each 0 0 0 0 Trash Rack,21" D-64 $ 306.84 Each 0 0 0 0 Page 6 of 7 SUBTOTAL 0 0 0 0 Unit prices updated:2/12/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 e Site Improvement Bond Quantity Worksheet Existing Future Public Private Bond Reduction* Right-of-way Road Improvements Improvements &Drainage Facilities Quant. lUnit Price Unit Quant. I Price 'Quant.J Cost Quant. I Cost Complete Cost PARKING LOT SURFACING No. 2"AC,2"top course rock&4"borrow PL-1 $ 15.84 SY 0 0 0 0 2"AC, 1.5" top course&2.5"base cour5 PL-2 $ 17.24 SY 0 0 0 0 4"select borrow PL-3 $ 4.55 SY 0 0 0 0 1.5"top course rock&2.5"base course PL-4 $ 11.41 SY 0- 0 0 0 WRITE-IN-ITEMS (Such as detention/water quality vaults.) No. WI-1 Each 0 0.00 0.00 0.00 WI-2 SY 0 0.00 0.00 0.00 WI-3+ CY 0 0.00 0.00 0.00 WI-4 LF 0 0.00 0.00 0.00 WI-5 FT 0 0.00 0.00 0.00 WI-6 0 0.00 0.00 0.00 WI-7 0 0.00 0.00 0.00 WI-8 0 0.00 0.00 0.00 VVI-9 0 0.00 0.00 0.00 vo-10 0 0.00 0.00 0.00 SUBTOTAL 1/ r�0.00 ,{ 0.00 �J�j 0.00 0.00 l SUBTOTAL(SUM ALL PAGES): "/ 71_✓ kt L( ealk 0.00 -6 . / V .00 0.00 / 30% CONTINGENCY&MOBILIZATION: 0.00 0.00 0.00 0.00 GRANDTOTAL: 0.00 0.00 0.00 0.00 COLUMN: B C 13 E Page 7 of 7 .,..--- 4r Zo, co/ 414E2itkCCD ,, m #2?Z,6 Unit prices updated:2/12/02 Version:4/22/02 REF 8-H BOND QUANTITY WORKSHEET.xls Report Date: 1/19/2010 E - OFF SITE ANALYSIS l i r OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT#2 NELSON PLAT JUNE 20,2012 Basin: Lake Washington Subbasin Name: John's Creek Subbasin Number: Symbol Drainage Drainage Slope Distance Existing Potential Observations of field Component Type, Component from site Problems Problems inspector, resource Name, and Size Description discharge reviewer, or resident see map Type:sheet flow,swale, drainage basin,vegetation, % '/.ml=1,320 ft. constrictions,under capacity,ponding, tributary area,likelihood of problem, stream,channel,pipe, cover,depth,type of sensitive overtopping,flooding,habitat or organism overflow pathways,potential impacts pond;Size:diameter, area,volume destruction,scouring,bank sloughing, surface areasedimentation,incision,other erosion A Sheet Flow Open grassed area from 6% Sta.0 None None None observed site sheet flows to CB at CB collects runoff the SW corner of property from Street—no on NE 12th Street. blockage problem B Pipe Flow 12"conveyance pipe from 6% Sta 0+00'- None None Adequate grade and size of pipe NE12th to the west to 7+50' to handle flows. Lincoln Place—before entering pond on southerly end of Jones Ave. C Pond Overgrown flat Sta 7+50' None None None observed D Pipe Flow Flow continues >20% Sta 7+50'— Was not able to N/A Based upon slope and size of Not observed downstream of the pond in 18+50' access structures downstream pipe,there appears to large pipe flowing towards down slope. Pipe be plenty of capacity for existing outlet area under NE Park system part of conditions. Drive and Lake Wash. City of Renton Blvd. Storm Water Utility inventory maps. E Open Channel System Pipe from hill side Sta. 18+50— Channel being None Good conveyance channel daylights into open channel 26+50 maintained near railroad crossing/NE Park Dr/Lake Wash Blvd , F - GEOTECH REPORT REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED 9-LOT PLAT RENTON,WASHINGTON S&EE JOB NO. 1116 OCTOBER 21,2011 S&EE gdece SOIL&ENVIRONMENTAL ENGINEERS,INC. 16625 Redmond Way,Suite M 124,Redmond,Washington 98052,(425)868-5868 October 21,2011 Mr.Phil Kitzes PK Enterprises 23035 SE 263`d Street Maple Valley,WA 98038 Report Geotechnical Investigation Proposed 9-Lot Plat 2008 NE 12th Street,Renton, WA We are pleased to present herewith our Report of Geotechnical Investigation for the referenced project. Our services were authorized by Mr.Phyllis Nelson on August 1,2001,and have been provided in accordance with our proposal dated July 29,2011. We appreciate the opportunity to provide our services. Should you have any question regarding the contents of this report or require additional information,please call. Very truly yours, SOIL&ENVIRONMENTAL ENGINEERS,INC. G1ENG • " 4 J ''` o -2/—// 28166 C.J. Shin,Ph.D.,P.E. '3610NAL EtyG NOv. 2.0/ L CC: Mr. Steve Lee 1116rpt S&E E TABLE OF CONTENTS Section Pagc 1.0 INTRODUCTION 2.0 SCOPE OF SERVICES 3.0 SITE CONDITIONS 2 3.1 SURFACE CONDITIONS 2 3.2 GEOLOGIC INFORMATION 2 3.3 COAL MINE,LANDSLIDE AND EROSION HAZARDS 2 3.4 TEST PIT FINDINGS 3 4.0 CONCLUSIONS AND RECOMMENDATIONS 3 4.1 GENERAL 3 4.2 SPREAD FOOTING 3 4.3 LATERAL EARTH PRESSURES 4 4.4 SITE PREPARATION,STRUCTURAL FILL AND DRAINAGE 6 4.5 SITE INFILTRATION 7 4.6 TEMPORARY AND PERMANENT EXCAVATIONS 7 4.7 SLAB SUPPORT 8 4.8 FLEXIBLE PAVEMENT 8 4.9 SEISMIC CONSIDERATIONS 9 4.10 ADDITIONAL SERVICES 9 5.0 CLOSURE 10 FIGURE 1: SITE LOCATION MAP FIGURE 2: SITE AND EXPLORATION PLAN FIGURE 3: SURCHARGE LOAD ON SUBSURFACE WALLS APPENDIX A:FIELD EXPLORATION LOGS AND KEY 1 I l6rpt i S&EE REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED 9-LOT PLAT RENTON,WA for Mr. Phyllis Nelson 1.0 INTRODUCTION We present in this report the results of our geotechnical investigation for the proposed development. The site is located at the current address of 2008 NE 12th Street in Renton,Washington. A site location map is shown in Figure 1 and a site and exploration plan is shown in Figure 2,both are included at the end of this report. We understand that the proposed development will involve 9 single-family lots,a new road,a storm water detention vault,and infiltration trenches. For the purpose of this study,we have assumed that the structural load of future houses will be typical of residential homes. 2.0 SCOPE OF SERVICES The purpose of our geotechnical investigation is to develop geotechnical recommendations regarding site preparation and foundation support. Specifically,our services included: 1. Exploration of soil and groundwater conditions underlying the site by the excavation of 4 test pits. 2. Review of published'information about potential coal mine and landslide hazards. 3. Recommendations regarding type of foundation support. 4. Recommendations regarding active and at-rest earth pressures to be used for the design of retaining structures. 5. Recommendations regarding passive soil resistance and coefficient of friction for the resistance of lateral loads. 6. Recommendations regarding temporary and permanent cut slopes. 7. Recommendations regarding support for slab-on-grade. 1116rpt S&EE 8. Recommendations regarding pavement design. 9. Recommendations regarding type of soil for seismic design. 10. Recommendations regarding site preparation, including removal of unsuitable soils, suitability of onsite soils for use as fill,fill placement techniques,and compaction criteria. 11. Five copies of a written geotechnical report containing a site plan, test pit logs, a description of subsurface conditions,and our findings and recommendations. 3.0 SITE CONDITIONS 3.1 SURFACE CONDITIONS The property is located in a residential area. NE 12th Street borders the site to the south and single-family residences border the site to the east,north and west. The site surface is relatively flat. Currently,a single- family occupies the site. At the time of this report,the majority of the site surface is covered with grass lawn. 3.2 GEOLOGIC INFORMATION Published geologic information (Generalized Geologic Map of Northwestern King County, Washington State Department of Natural Resources) indicates that the site area is underlain by Recessional Stratified drift(Qvr). The material is mainly a light-gray sand with gravel. 3.3 COAL MINE,LANDSLIDE AND EROSION HAZARDS Coal mine hazards map prepared by City of Renton, Public Works Department, Technical Services,May 21, 2009 indicates no known mine at the site. Sensitive Areas Map published by King County indicates no landslide or erosion hazards at the site. 1116rpt 2 S&EE 3.4 TEST PIT FINDINGS The subsurface conditions underlying the site were explored by the excavation of 4 test pits,TP-1 to TP-4. The approximate test pit locations are shown on Figure 2. Details of the field exploration program and the test pit logs are included in Appendix A. Our test pits reveal that the site is covered by a few inches of topsoil and is underlain by sands. The sands are brown and gray in colors and are generally medium dense to dense. Judging from its color,constitution and density,we believe that these materials are native soils identified as the stratified drift in the geologic map. No groundwater was encountered in any test pit. 4.0 CONCLUSIONS AND RECOMMENDATIONS 4.1 GENERAL It is our opinion that the proposed development is feasible from a geotechnical standpoint. We believe that conventional spread footings can be used for foundation support. 4.2 SPREAD FOOTING Spread footings should be founded on native sands that are at least medium dense. Recommendations for footing design and construction are presented below. Allowable Bearing Loads: Footings may be designed using an allowable bearing load of 3,000 psf(pounds per square feet). This value includes a safety factor of at least 3,and can be increased by one-third for wind and seismic loads. Settlement: Interior column footings designed in accordance with the above recommendations are expected to experience approximately 1/2 inch of total settlement. Continuous wall footings should experience settlement of about 1/4 to 1/2 inch. Differential settlement between adjacent footings is expected to be about 1/4 inch. The settlement will occur rapidly,essentially as the loads are applied. Lateral Resistance: Lateral resistance can be obtained from the passive earth pressure against the footing sides and the friction at the contact of the footing bottom and bearing materials. The former can be obtained using an equivalent fluid density of 250 pounds per cubic foot(pcf),and the latter using a coefficient of friction of 0.5. These values include a safety factor of 1.5. 1116rpt 3 S&EE Footing Near Slopes: For any footings near slopes of 15 percent or steeper,the bottom of the footing must be positioned in such a way that the horizontal distance from the outside footing edge to the slope face is at least 10 feet. Footing Construction: All footing subgrades should be observed by an engineer from our office. Our engineer will confirm the bearing capacity of the subgrade material and provided recommendation for subgrade preparation, if necessary. If our test pits coincide with the future footing locations,the upper 4 feet of the backfill in the test pits should be removed and then backfilled with structural fill. All exterior footings should be founded at least 18 inches below the adjacent finished grade to provide protection against frost action,and should be at least 18 inches in width to facilitate construction. 4.3 LATERAL EARTH PRESSURES Lateral earth pressures on retaining walls or permanent subsurface walls,and resistance to lateral loads may be estimated using the following recommended soil parameters: Equivalent Fluid Unit Weight(PCF) Coefficient of Friction Active At-rest Passive Native Soils or 40 50 25() 0.5 Structural Fill Note: Hydrostatic pressures are not included in the above lateral earth pressures. The active case applies to walls that are permitted to rotate or translate away from the retained soil by approximately 0.002H,where H is the height of the wall. This would be appropriate for a cantilever retaining wall. The at-rest case applies to unyielding walls,and would be appropriate for walls that are structurally restrained from lateral deflection such as basement walls,utility trenches and pits. 1116rpt 4 S&EE SURCHARGE INDUCED LATERAL LOADS 1) Additional lateral earth pressures will result from surcharge loads from floor slabs or pavements for parking that are located immediately adjacent to the walls. The surcharge-induced lateral earth pressures are uniform over the depth of the wall. Surcharge-induced lateral pressures for the "active"case may be calculated by multiplying the applied vertical pressure(in psf)by the active earth pressure coefficient(Ka).The value of Ka may be taken as 0.3.The surcharge-induced lateral pressures for the"at-rest"case are similarly calculated using an at-rest earth pressure coefficient (Ko)of 0.5. For surcharge loads that are not adjacent to the wall,the induced lateral earth pressure will depend on the magnitude of the surcharge and the distance from the wall. Such induced lateral load can be estimated using the equations shown on Figure 3. 2) The slope-induced lateral earth pressure can be accounted for by increasing the effective height of the wall by one-half the slope height. For back slope continues beyond a horizontal distance equal to the height of the wall,only the part of slope-rise within this horizontal distance should be considered. 3) The traffic-induced lateral earth pressure can be accounted for by increasing the effective wall height by 2 feet. SEISMIC INDUCED LATERAL LOADS Seismic induced lateral loads should be included for the design of retaining walls with imbalanced lateral loads. The dynamic force can be assumed to act at 0.6 H above the wall base. The magnitude can be calculated as 8H(psf),a uniform load over wall height H. BACKFILL IN FRONT OF RETAINING WALLS Backfill in front of the wall should be structural fill. The material and compaction requirements are presented in Section 4.4 of this report. The density of the structural fill can be assumed to be 130 pounds per cubic feet. BACKFILL BEHIND RETAINING WALLS Backfill behind the wall should be free-draining materials which are typically granular soils containing less 1116rpt 5 S&EE than 5 percent fines(silt and clay particles)and no particles greater than 4 inches in diameter. The backfill material should be placed in 6 to 8-inch thick horizontal lifts and compacted to at least 95 percent of the maximum density in accordance with ASTM D-1557 test procedures. Care must be taken when compacting backfill adjacent to retaining walls,to avoid creating excessive pressure on the wall. DRAINAGE BEHIND RETAINING WALLS Rigid,perforated,PVC drainpipes should be installed behind retaining walls. Drainpipes should be at least 4 inches in diameter,covered by a layer of uniform size drain gravel of at least 12 inches in thickness,and be connected to a suitable discharge location. An adequate number of cleanouts should be installed along the drain line for future maintenance. 4.4 SITE PREPARATION, STRUCTURAL FILL AND DRAINAGE Site preparation should begin with stripping vegetation and topsoil of the structural areas including the driveway,building and slab. The subgrades should then be thoroughly proof-rolled using heavy construction equipment. Areas which are found to be loose or soft,or which contain organic soils should be over-excavated. An engineer from our office should observe the proof-rolling and evaluate the over- excavation requirements. After stripping,over-excavation and excavation to the design grade,the top 12 inches of the native soils should be re-compacted to at least 92%of their maximum dry density as determined using ASTM D-1557 test procedures(Modified Proctor test). Structural fill can then be placed in the over-excavation and fill areas. The structural fill materials should meet both the material and compaction requirements presented below. Material Requirements: Structural fill should be free of organic and frozen material and should consist of hard durable particles,such as sand,gravel,or quarry-processed stone. The on-site sandy soils are suitable for structural fill. These soils are moisture-sensitive and should be moisture- conditioned to+1-2%from their optimum moisture contents prior to use. Suitable imported structural fill materials include silty sand,sand,mixture of sand and gravel (pitrun),and crushed rock. The use of quarry spalls and crushed recycled concrete should be evaluated by our engineer. All structural fill material should be approved by our engineer prior to use. 1116rpt 6 S&EE Placement and Compaction Requirements: Structural fill should be placed in loose horizontal lifts not exceeding a thickness of 6 to 12 inches,depending on the material type,compaction equipment, and number of passes made by the equipment. Structural fill should be compacted to at least 95% of the maximum dry density as determined using the ASTM D-1557 test procedures. SITE DRAINAGE The site surface should be graded so that surface water is directed away from the structural areas. Standing water should not be allowed. Final site grades should be sloped away from the building unless the area is paved,or yard drains installed to collect surface runoff. 4.5 SITE INFILTRATION It is our opinion that infiltration to the native sands is feasible. Based on our field observation and experience with the material,we recommend an infiltration rate of one inch per hour. We believe that this value includes a safety factor of at least 3. Setback from Structures: Infiltration facilities can cause local mounting of groundwater table. This mounting may result in seepage at ground surface in the neighboring properties or facilities. To mitigate such risk,we recommend that the infiltration facilities be located at least 15 feet from any structures. 4.6 TEMPORARY AND PERMANENT EXCAVATIONS When temporary excavations are required during construction,the contractor should be responsible for the safety of their personnel and equipment. The followings cut angles are provided only as a general reference: For temporary excavations less than 3 feet in depth,the cut bank may be excavated vertically. For temporary excavations greater than 3 feet in depth,the cut should be sloped no steeper than 1H:1 V(one horizontal to one vertical). Flatter slopes for all temporary cuts may be required if seepage occurs. All permanent slopes should be no steeper than 2H:1 V. Water should not be allowed to flow uncontrolled over the top of any slope. Also,all permanent slopes should be seeded with the appropriate species of vegetation to reduce erosion and maintain the slope stability. 1116rpt 7 S&EE 4.7 SLAB SUPPORT Assuming that the site is prepared per recommendations presented in Section 4.4 of this report,all slabs can be soil-supported. We envision that the slab subgrade will be disturbed and loosened by construction activities at the time of slab construction. We therefore recommend that the slab subgrade be proof-rolled prior to concrete placement. Any wet and loose areas should be over-excavated and backfilled with structural fill. In order to promote uniform support and provide a capillary break,we recommend that slabs be underlain by a 6 mil.vapor barrier over a 4-inch thick layer of free draining gravel. 4.8 FLEXIBLE PAVEMENT We recommend that the subgrade for flexible pavement be prepared in accordance with the recommendations presented in Section 4.4 SITE PREPARATION. Based on the subsoil conditions,we believe that the prepared subgrade will have a California Bearing Ratio(CBR)of at least 12. We therefore recommend the following flexible pavement sections for light and medium traffic conditions: Light traffic(Daily EAL=5 or less): 2 inches asphaltic concrete over 4 inches base course Medium traffic(Daily EAL=20 to 80): 3 inches asphaltic concrete over 6 inches base course The base course should be compacted to at least 95 percent of the maximum dry density as determined by ASTM D-1557 test method. The material should meet WSDOT aggregate specification 9-03.9(3)and have the following gradation: Sieve Size Percent Passing 1 1/4-inch 100 5/8-inch 50-80 1/4-inch 30-50 US No.40 3-18 US No. 200 7.5 max. %Fracture 75 min. 1116rpt 8 S&EE 4.9 SEISMIC CONSIDERATIONS We recommend that Site Class C as defined in the 2009 IBC be considered for the building design. The site is underlain by dense soils. As such,the liquefaction potential is negligible. 4.10 ADDITIONAL SERVICES Additional services may be required during the design and construction of the project. We envision that these additional services may include the following: 1. Review of design plans. 2. Provision of construction monitoring services.The tasks of our monitoring service typically include the followings: 2.1 Monitoring of site preparation. 2.2 Monitoring of foundations installation. Our representative will confirm the capacity of the foundation bearing soils,and will assist the contractor in evaluating the over-excavation requirements,if any. 2.3 Monitoring the placement and compaction of structural fill. Our representative will confirm the suitability of the fill materials,perform field density tests,and assist the contractor in meeting the compaction requirements. 2.4 Monitoring the installation of subsurface drains. Our representative will confirm that these drains are installed in accordance with our recommendations. 3. Other geotechnical issues deemed necessary. 1116rpt 9 S&EE 5.0 CLOSURE The recommendations presented in this report are provided for design purposes and are based on soil conditions disclosed by field observations and subsurface explorations. Subsurface information presented herein does not constitute a direct or implied warranty that the soil conditions between exploration locations can be directly interpolated or extrapolated or that subsurface conditions and soil variations different from those disclosed by the explorations will not be revealed. The recommendations outlined in this report are based on the assumption that the development plan is consistent with the description provided in this report. If the development plan is changed or subsurface conditions different from those disclosed by the exploration are observed during construction,we should be advised at once so that we can review these conditions,and if necessary,reconsider our design recommendations. S&EE tetw+ m { .. - ':,-‘,..;:---p, x N ork hear i'reek Hifi-Novelty Fi Waste East alt e 4 Kirkland Q Hit- ill r'` A fit C'• m m s�u:h Redmond ori C) Yarrow Pant �' I:�.`Ga, S20 Hunts Poant _ .SafTlfTlr�1Y11Sf1 ri Clyde Hill a Ames Lake Lake R' tS c^heal Washington Medina } �h p e�.e, e C) rJe2s1 e`. Seattle - Bellevue c �, a , * L8 e imtaw, 202 e Sernmerrim 4 , " I r tPlBeaux Arts Mercer V stage coP, island Eastgate —a- ei Providence a. rt .nw ic Point ff a *taXe++caf1 u74 �� Boeing Feld k ng Newcastle enae t � ,� Inferna;ch inir r, r,t Ialu White gg C.at creek s [V✓ Issaquah re..rrteruy Center eon,,aa, Coni ar g00 a ,r„� h4pimtain Q q t Bryn tir 4 L""'J 'e Mawr-Skyway r'"mss* squak Mauntein West Tiger �aln-�r; State Park ��. ,.`& Creea. MOrantafrt ,,Af14v-Ire "#t East Renton Natural Area T�hwila Renton Seanursr 6unen tw urr,oai Highlands Gr Arpai Mirrormont 4iritilcta: SeaTac Maple Cascade-Farrwood Heights-Lake Tx:rr a Desire Normandy $ inr a.cc,ti Park <.i,ra Benson!-u Cedar tl,,t .“I East ` �� Hobart hri. Htft-Mendran �. Des Moines ` ` _,-,Er;; E 2,6t ± o SEX;24th Sr s o 4 aemws enrth n SL 210th St Vi114gfi Kent h Uro60h __ McPI 02011 Google- S&EE Figure 1 Site Location Map '.--' FENCE CE ‘,._.,. 2 ' - \ S 07' . - 44 Al 1.3' EDGE CO17.67; FOUND MAG/WASHER IWALL -7STRONG 15986 ON-LiNE t , t \ I ) t.„ COR. WO D FENCE 1 Po \ S 4'X 1 _ 8/20/2011 G ACCEPT:p. --- R'(.. GARAGE /0 ,,,N, 1-' GRAM/\ 1 ----- -___ ----- -..1 i / ., 1 1 tio ; ° IF --_, \fi I \, TP-4;r c5a? 11 1 i- -** /1J1',," R ------ --......,,. 4t / C) I C.Q;71 .17 ------.2.-- o -- - — --___ z APPROXIMATE LOCATION P , = PEirciftILANTON /ig / 1,1 GRASS__,--2 14---- --- -111 -- _ -- - _SF - , _ - -----_.;...?.. I In ,,1) 'N 2" APLE I / . °I / -- % APPLE / (47. — -S- TP-2 \ 1 T I )6 1 , ,,,:, i ssco \ 0 , . , _....._.. ,FE=275. ilk -----\ le I 1 11 \ ° , IN 1 iivx .,,,vE14,A4 .......:. ‘ 0 1 2" APPLE . 0 1 HOUSE I e- —i--- 4 — c',1•7 • -'' - _ .ODOMED I cv fs) --4 1 42 1811/ g),/ .*.''0..* ' i 1 i uGP LpCAIT: ii * Ill . \ ) 61 I S- -'----- • 1 cvli j . ....,WA Y • UT=267.5•74 . - I I ENC11-_,.., I 0 11, . i 2.;r , .m •. --. . •,.; 1 ..0 / ?• ' i -- t , 0'4 ‘ 4 , il 6 1 m i r.j)1 P-1 1 N •Illtt Z.1/4 1 Csi iir , "•„;,4/ \ CNI \ i --\A-I : 9 o- 1 gl),rl' \ \ , . c4k:f \ -LOT-+— _ _ .........__ ___ --6-\ r Pre, \ 111, I * 1 2 2 ri'-' i i AREA'-= 70,742 SQ. FT. \\, . -•* 'illi\.*: \ '1 '2 .. AC ES . I 14 \ E 8 m V°,)7) 1 N t irk , .N. /w4 \ \ GRASS - I 1 \ 1 4 1\ ik'2 \ N i LA - 1 K. \ <7, ,s., II --, 0 ',. f..1..,,, I -:=1 I's ..-. \ , OP•,,, ti, ,s, _ -- _.., , I ir . • \ ....,_. „_•, \ G . ,---)•,„,.•.•, \ \ *, ,RASS \ © DRAINAGE ' , 7,)1 , , 1 TRACI'oxik4A' , ':'40,tr, , \ \ \ \ \ \ _ , L, CITY 0 '11:"`?C=‘-t 1 \ \ I 11 I\ I ': -3 SEWER ASBI . t.) ‘7_,. 0 • • TP-1,\ ''-'; •,. \\ 1 \ .1: II\ \ •u 4 l \ 0 I , • „ 11 it: \ Im. 0 \\ , I \ I II , 11 • . \ ...• II I TP-3 \ I \ F•UND 1;(2" REBAR VN/CAP I .S\NO. 5525 pYLER ,, 20 :, 1 . a I \ l'• I A{idyl = z I . si ...., lit. \ 6 \ \ . \ ''\ 1' . / \IF 12" C . Q• i . ii• io•N\ - - k,„, 1 / • pep tt./111 ...„,' - w . r -Cr-Alt 1111111 _Allrib / k.";zr'% . .11111;f li±.10. '''.-A al ANSI- . .:'• 2( . INNEViiiVAIIIIIIMINITir - l:V%:,%7reirilligkirliKSIEWIMMIIMALIRAIMINISMIMINIIIIIMMIIIIIMA7.- ' ‘1111111111P .'ret•W.7;,7--,;>•.< I "- •,• ' r*.: \ '' ' DI ?MTD ,4%., i C. .•.nut:,• + moo NE 12th Street m• ••• nom. A .... _ . ...... 30 15 0 30 60 • N Reference:DGrading&Roadway Plan by Prefered Engineering, LLC, 6/28/11 I S&EE Figure 2 TP-1: Test pit number and approximate location Job no. 1116 Site and ExplorationPlan 00 - . m=0.1 \` 0.2 �'N �' \ 1 0.2 _ \ m=0.6 \ \\ m=0.5- I m.o. m=o.7 / 04 M=0.3 X04 �' • � N / m= � 0.4 N / � C u_0.6 // 0 0.6 o /7m R ' / m WOR J // -J P // 0.1 .60H > 0.2 .78 .59H > / 0.3 .60H i 0.4 .78 .59H 0.8 / 0.5 .56H 0.8 / 0.6 .45 .48H 0.7 .48H ///!/ / I.0o .2 .4 .6 .8 I.0 Ip0 .5 1.0 1.5 H2 VALUE OF °H (0-L ) VALUE OF aH (- ) POINT LOAD Qp Q X=mH P 1 LINE LOAD 0L Z=nI H MI pH FOR m < 0.4 WAk XunH crH( H )- 0.20n H crH �L (0.16+n2)2 R FOR m.0.4: Z=nH PH: 0.550 ( H2)= 0.28 n2 L H (016�n2)3 a' I__ m)0.4: ' - FOR m )0.4: H � �r H _ 1.28m2n H2 _ pI77m2n2 R111 H (�) (m2+n2)2 �H (Q ) (m2+n2)3 RESULTANT P = 0.64QL 0H =vHCOS2(I.19) . . , crti PRESSURES FROM LINE LOAD QL -J 6 _,X a ' (BOUSSINESQ EQUATION MODIFIED BY EXPERIMENT) 3 wv vH rX=mH SECTION A-A PRESSURES FROM POINT LOAD Op (BOUSSINESQ EQUATION MODIFIED BY EXPERIMENT) eference: Foundations and Earth Structures, Design Manual 7.2, Department of the Navy, May 1982 Calculation of Surcharge Loads on Subsurface Walls Figure 3 APPENDIX A FIELD EXPLORATION AND LOGS The soil conditions underlying the project site were explored by the excavation of 4 test pits on August 15, 2011. The approximated test pit locations are shown on Figure 2-Site and Exploration Plan which is included at the end of this report. The test pits were excavated with a Case 580 backhoe. A representative from S&EE was present throughout the exploration to log the subsurface soil conditions. All test pits were backfilled with the excavated soils. The backfill were placed in 2-foot thick lifts and compacted with the backhoe bucket. Test pit logs are presented in this appendix. A chart showing the Unified Soil Classification System is included at the end of this appendix. I t l6rpt S&EE co w o w a . o � Test Pit TP-1 30 U E a 0 m S E j Soil Description —0 SP 3-inch thick topsoil with grass roots _ SP Gray and brown fine to medium sand with trace silt(dry to damp)(medium dense) !iPJee�ee�" 2_�:ane: —g SP Gray fine to medium sand (moist)(medium dense to dense) —10 Test pit completed at a depth of 10 feet. No groundwater was encountered during excavation. Client: Mr.Phyllis Nelson Exploration Method: Case 580 backhoe Exploration Date: August 15,2011 Ground Elevation: 272 feet Figure A-1 S&EE Proposed 9-Lot Plat Job No,1116 a > o .c o Test Pit TP-2 Cr o m ;c J Soil Description —0 , SP 3-inch thick topsoil with grass roots SP Brown fine sand(dry)(medium dense) SP Gray fine to medium sand (dry to damp)(medium dense to dense) —6 -damp to moist and dense below 9 feet —10 Test pit completed at a depth of 10 feet. No groundwater was encountered during excavation. Client: Mr.Phyllis Nelson Exploration Method: Case 580 backhoe Exploration Date: August 15,2011 Ground Elevation: 276 feet Figure A-2 S&EE Proposed 9-Lot Plat Job No.1116 10 0 E phi k a ° Test Pit TP-3 >U w Z k a v a O UU cco 0 ciii O m _ c Soil Description O , SP :i42,- 3-inch thick topsoil with grass roots SP Brown fine sand(dry)(medium dense) i1 -i=5: ejiPi: — SP Grayish brown fine to medium sand (dry to moist)(medium dense to dense) —6 ...........:...... — -moist and dense below 9 feet '-'--- Test pit completed at a depth of 10 feet. No groundwater was encountered during excavation. Client: Mr. Phyllis Nelson Exploration Method: Case 580 backhoe Exploration Date: August 15,2011 Ground Elevation: 258 feet Figure A-3 S&EE Proposed 9-Lot Plat Job No.1116 o 2 Test Pit TP-4 _a io Oct a °'ct fa- 0 0 m __ Soil Description 0 SP 3-inch thick topsoil with grass roots SP Brown fine sand(dry)(medium dense) SP Grayish brown fine to medium sand,trace silt&trace fine to medium gravel (damp)(very dense) 6 Test pit completed at a depth of 6 feet. No groundwater was encountered during excavation. • • Client: Mr. Phyllis Nelson Exploration Method: Case 580 backhoe Exploration Date: August 15,2011 Ground Elevation: 264 feet Figure A-4 S&EE Proposed 9-Lot Plat Job No.1116 UNIFIED SOIL CLASSIFICATION SYSTEM w . W DESCRIPTION MAJOR DIVISIONS N L. UJ GW WELL-GRADED GRAVELS OR GRAVEL-SAND MIXTURES, CLEAN 0 LITTLE OR NO FINES w Q • POORLY-GRADED GRAVELS OR GRAVEL-SAND MIXTURES, GRAVELS z m w GP (LITTLE OR J 4 p z w ¢y _j • LITTLE OR NO FINES NO FINES) LU I 0 a y > Q w SILTY GRAVELS,GRAVEL-SAND-SILT 5 F W c,W ti y c,W GM GRAVELS � • _ MIXTURES WITH FINES 0 'a o LU 1_1 <N • GC CLAYEY GRAVELS,GRAVEL-SAND-CLAY (APPRECIABLE °S I W Z o 8 0, MIXTURES AMOUNT OF FINES) R- SW WELL-GRADED SAND OR GRAVELLY SANDS, CLEAN o a z 0 Iz LITTLE OR NO FINES psov 'it) W a, w SANDS ,,.z0 & U) IT-m ,w SP POORLY-GRADED SANDS OR GRAVELLY SANDS, (LITTLE OR -°z w N> Ct w Lu ,o LITTLE OR NO FINES NO FINES) C/) 1154 5 o ; Q Fc' 0 0 Z =��w ay o SI Pf SM SILTY SANDS,SAND-SILT MIXTURES SANDS Q ,w w,,, a 0 w fn p -I WITH FINES - oar 5N Wo ' SC CLAYEY SANDS,SAND-CLAY MIXTURES (APPRECIABLE 202 2 o D % N W AMOUNT OF FINES) CO CO-1 INORGANIC SILTS,VERY FINE SANDS,ROCK FLOUR,SILTY OR i ML CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY N w d • CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,GRAVELLY SILTS & CLAYS — w N N CLAYS,SANDY CLAYS,SILTY CLAYS,LEAN CLAYS > a LIQUID LIMIT LESS THAN 50 U) w 8 F ORGANIC SILTS AND ORGANIC SILT-CLAYS OF LOW D �' o w OL PLASTICITY Z o MH INORGANIC SILTS,MICACEOUS OR DIATOMACEOUS FINE =a ~ 1 SANDY OR SILTY SOILS,ELASTIC SILTS I INORGANIC CLAYS OF HIGH PLASTICITY,FAT I CID 1! CH CLAYS SILTS & CLAYS Z W W LIQUID LIMIT GREATER THAN 50 0 a __ OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, , LL ORGANICSILTS IIIPT PEAT AND OTHER HIGHLY ORGANIC SOILS HIGHLY ORGANIC SOILS Ni DEPTH OF STANDARD PENETRATION TEST DEPTH OF UNDISTURBED(SHELBY TUBE)SAMPLE 2 DEPTH OF GROUNDWATER DURING DRILLING SOIL CLASSIFICATION CHART I AND KEY TO EXPLORATION LOG S&EE