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HomeMy WebLinkAboutSWP272913(2) i 1 ERRICO SHORT PLAT 1 Technical Information ' Report May 17, 2001 Owner/Developer: Joe Pruss Basic Ventures Inc. 21305 NE 6th Place Redmond, WA 98074 r Prepared by: Robert Stewart ' Reviewed by: ' Jennifer A. Steig, P.E. ETERSON � `3������ '11�� (C O N S U LT I N G jORAL EXPIRES 09/09/02 ' 4030 LAKE WASHINGTON BLVD,NE,SUITE 200 KIRKLAND,WASHINGTON 98033 PCE Job No. BAVE-0001 r r ' TABLE OF CONTENTS rI. PROJECT OVERVIEW 1 H. CONDITIONS AND REQUIREMENTS SUMMARY 4 TASK 1: STUDYARF-4 DEFINITION&NL4PS 8 ' TASK 2:RESO URCE REVIEW 8 TASK 3:FIELD INSPECTION 12 TASK 4:DRAINAGE SYSTEM DESCRIPTIONAND PROBLEM SCREENING 13 rIV. FLOW CONTROL AND WATER QUALITY ANALYSIS AND DESIGN 14 Existing Site Hydrology 14 Developed Site Hydrology 15 rStorage Facility 17 IV. CONVEYANCE SYSTEMS ANALYSIS AND DESIGN 18 VI. SPECIAL REPORTS AND STUDIES 18 VII. OTHER PERMITS 18 r VIH. ESC ANALYSIS AND DESIGN 18 r IX. BOND QUANTITIES,FACILITY SUMMARIES AND DECLARATION OF COVENANT 19 XI. OPERATIONS AND MAINTENANCE MANUAL 19 1 1 r Peterson Consulting Engineers Page i 1 FIGURES Figure 1: Vicinity Map 3 Figure 2: Site Map 4 Figure 3: Basin Map 9 Figure 4: SCS Soils Map 11 Figure 5: Existing Conditions Map 17 Figure 6: Developed Conditions Map 18 APPENDIX A Water Works Output (Developed and Existing Flow Rates) 2 year, 10 year, and 100 year isopluvials SCS western Washington curve numbers Hydrologic soil group table for King County rRiser Inflow Curve APPENDIX B King County Level One Tables and Maps APPENDIX C King County Drainage Basin Map King County Community Planning Areas Sensitive Area Folio Maps (Landslide, Seismic, Erosion, Coalmine, Streams and 100-Year Floodplains and Wetlands) APPENDIX D Geotechnical Report APPENDIX E Maintenance Guidelines for Storm/Conveyance System Peterson Consulting Engineers Page ii Technical Information Report for Errico Short Plat Mav 17, 2001 I. PROJECT OVERVIEW Project: Errico Short Plat PCE Job Number: BAVE - 0001 �I Site Area: The site consists of 26,572 Square feet—0.61 Acres. Site Location: The site is located within the City of Renton on the south side of NE 24t' Street, and east of Aberdeen Avenue, (see Figure 1: Vicinity Map). More specifically, the site is located within SE '/4 of Section 5, Township 23 North, Range 5 East, W.M. Existing Adjacent Development: Existing development adjacent to the site includes the following: North—NE 24"' Street ' East— Single Family Residential South— Single Family Residence West— Single Family Residence Pre-developed Site Conditions: The existing site runoff patterns are generally from east to west on the entire site. The slopes range from 0 - 6%, mostly flat through out the site. An existing single- family residence is located on the northern portion of the site. The ground cover ' consists of mostly poorly maintained lawn (acting as a pasture / meadow) on the remaining portions of the site. Peterson Consulting Engineers Page I Technical Information Report for Errico Short Plat Mav 17, 2001 Post-developed Site Conditions: The proposal is to construct 3 lots with associated roads and utilities. (See Figure 2: Site Map). Runoff patterns from the developed site will be similar to the existing conditions. The runoff from the proposed roads will be conveyed via tightline system on the west side of the property, then north to the to the NE 241h Street storm drainage system. The runoff from the roof drains will also be conveyed using the NE 241' Street storm drainage system. See Section IV for a detailed discussion and calculations. Peterson Consarlting Engineers Page 2 F7 MAY CREEK PARK ' NE 28th ST NE 28th ST ' KENNYDALE LINOS PARK NE 24th ST o COUL ON Z BEACH NE 20th ST SITE ■ z � Zo VICINITY MAP ERR/CO SHORT PLAT SEC. 5, TWP 23 N., RGE. 5 E., W.M. D WN. BY: DATE: JOB NO. x 4030 Lake Washington k LETERSON Blvd. N.E., Suite 200 BMD 5117101 GAVE-000l SULTING Kirkland, WA 98033 Tel (425) 827-5874 CHKD. BY.' SCALE: FIGURE: `c Fax (425) 822-7216 RS NSA 1 SEC 5, TWP.23N,, RGE. 5E, W.M. m 1 N. E 24'#h S T 1323.06 4444444a4444 N89'07'09'E 26' — � — --j--- 160.OS FOUND MON ' FOUND MON — — — — — — I IN CASE IN CASE Kph 30' -- - --- 1 _ 122.57 o � oWe 1p1 m�mZS ZiZ _ � 2 0 40' SCALE. 1"" = 40' _ Vic I ti vzi I ' 26' INGRESS, EGRESS AND o N 1 UTILITY EASEMENT i I v- Q ZW 3 g w I U- ! I._ CL Z L6 h (� N ' 0 W L.Lj ; Q I N Uj o I' o oI I;o w cr - z z I 111 I i1� ; I < I N89°7 332"E 122.55 STAMP N0T VALID UNLESS SIGNED AND DATED �+ T CONSULTING NGC �7 20th I . CONSULTING NE 20 th S T. 4030 Lake Washington o — FOUND MON Blvd. N.E., Suite 200 o _ FOUND MON -.._,-, _ _ _.-, .. I N CASE Kirkland,WA 96033 - Tel (425)827-5874 m IN CASE Faa (425) 622-7216 1'f JDBNUMBER ^I t V/^ FIGURE tl -0D01 n 2 h 6j Technical Information Report for Errico Short Plat Hav 17, 2001 II. CONDITIONS AND REQUIREMENTS SUMMARY CORE REQUIREMENTS: Core Requirement # 1: Discharge at the Natural Location The proposed conveyance system will be release at the natural discharge point for the project. Core Requirement# 2: Off-Site Analysis See Section III of this report. Core requirement # 3: Runoff Control ' See Section IV of this report for detailed discussion and calculations regarding detention. It was found after competing the calculations in section IV, that a detention system is not ' necessary per the exemption in the 1990 KCSWDM 1.2.3-5, See Section IV. Core Requirement# 4: Conveyance System The proposed conveyance system will collect and contain the stormwater from the site. Core Requirement # 5: Erosion/ Sediment Control Plan In accordance with the City of Renton Standards, a temporary erosion control plan will be ' designed and provided at the time of preparation of the construction documents. ' Core Requirement # 6: Maintenance and Operation See Section XI of this report. Core Requirement # 7: Bonds and Liability A bond quantities worksheet will be completed after first review. The project owner will provide bonding as required by the city of Renton. Peterson Consulting Engineers Page 5 i Technical Information Report for Errico Short Plat Mav 17, 2001 ' SPECIAL REQUIREMENTS: ' Special Requirement # 1: Critical Drainage Areas The project is not designated in a critical drainage area or in an area included in an adopted master drainage plan, lake management plan or shared facility drainage plan. Special Requirement#2: Compliance with an Existing Master Drainage Plan The project is not designated in a master drainage plan, therefore no special requirement is needed. Special Requirement# 3: Conditions Requiring a Master Drainage Plan The project is not designated in a master drainage plan; therefore no special conditions are required. Special Requirement#4: Adopted Basin or Community Plan The project is located in the Cedar River Basin and East Lake Washington sub-basin but is ' not subject to any specific requirements per the plan. 1 Special Requirement # 5: Special Water Quality Controls Water quality will does not need to be provided according to the 1990 KCSWDM (sec 1.3.5 Special Requirement #5 — Special Water Quality Controls). Water quality only needs to be provided if more than 1 acre of impervious surface is being added, and our site is only adding approximately 0.17 acres of new impervious. Special Requirement # 6: Coalescing Plate Oil/Water Separators The proposed project is not subject to this requirement. Special Requirement # 7: Closed Depressions ' The proposed project does not contain any closed depressions. Peterson Consulting Engineers Page 6 Technical Information Report for Errico Short Plat May 17, 2001 Special Requirement# 8: Use of Lakes, Wetlands or Closed Depressions for Peak Runoff Control The proposed project is not subject to this requirement. Special Requirement # 9: Delineation of 100-Year Floodplain The proposed does not lie with in a 100 year flood plain, therefore the project is not subject to this requirement. Special Requirement# 10: Flood Protection Facilities for Type 1 and 2 Streams The proposed project is not subject to this requirement. Special Requirement # 11: Geotechnical Analysis and Report See Appendix D for the geotechnical report. Special Requirement # 12: Soils Analysis and Report The proposed project is not subject to this requirement. Peterson Consulting Engineers Page 7 Technical Information Report for Errico Short Plat Mav 17, 2001 III. OFF-SITE ANALYSIS TASK 1: STUD YAREA DEFINITION& MAPS The 0.61-acre site is located on the south side of NE 24`h St, and east of Aberdeen AVE NE, in the City of Renton, Washington. More generally, the site is located in the SE '/4 and NE '/4 of Section 5, Township 23 North, Range 5 East W.M., in King County, Washington (see Figure 1: Vicinity Map). The site is in the Cedar River Drainage Basin and East Lake Washington Sub-basin as defined in the King County Basin Reconnaissance Program Summary Volume I (see King County Drainage Basins Map in Appendix "C"). ' UPSTREAM DRAINAGE ANALYSIS There is approximately .28 acres of upstream area tributary to the site (see Figure 3: Basin Map). This contributing area is coming from the lots located to the east and southeast of the site. TASK 2: RESOURCE REVIEW Support documentation for the following items may be found in the Appendix. Community Plan The site is located in the Newcastle Community Planning Area (see Community Planning map in Appendix"C"). Adopted Basin Plan /Basin Reconnaissance Summary Report tThe site is located in the Cedar River Basin and East Lake Washington Sub-basin. No basin reconnaissance report could be found for this basin. Critical Drainage Area The site is not located in any of the Critical Drainage Areas as identified in the 1998 King County ' Surface Water Design Manual. Peterson Consulting Engineers Page 8 i I b Ld Q ■ Q I /' - a � 1 a N 1 c • � o II� I � o N N N ['n I 1 252.3 1 1 9s �/3 85 &S l6- -1' 1 1 6.1 / e UPST1 0 C0�'[+tlZ4VTrNh ARe� J _ 130 / ' l . 23 2 35 25 �. --- 12 �L! —— —— h iz9.52 &3 ^�28 So 2 34 26 2-4-- Sim, W �, /30 W Z [� a 33 27 Q r w � 03 8pr [' 4 4 3A 75' ��T 31 30 29ca 0� 5 Q 2 I t! -40 _ , ---- -- $ N.E. 30 23RD \ 0; 40 o✓ 69 g447 �j 47 10 11 12 13 Ih 14 0J5 16, iii. 61- - - 1 6. 53.07 s. �� 109 m n .-1�'- n tl c n co �wc_�c 1 1 BASIN MAP ERRICO SHORT PLAT SEC. 5, TWP 23 N., RGE. 5 E., W.M. D WN. B Y.• DA TE: JOB NO. m� 4030 Lake Washington o ETERSON Blvd. N.E., Suite 200 BMo 1//7/01 BA vE-0001 CONSULTING Kirkland, WA98033 W Tel(425) 827-5874 CHKD, BY. SCALE: FIGURE: Fax(425) 822-7216 RS N/A 3 Wo �s Technical Information Report for Errico Short Plat May 17, 2001 Sensitive Area Folio The King County Sensitive Areas maps dated 1990, revealed that the site was not located in hazard areas, such as, landslide, coal mines, erosion and seismic. The site does not contain any 1 classified wetlands or streams (see Appendix"C" for maps). SCS Soil Survey The soils on the site, per the SCS Soils mapping, are LnC — Indianola Finny Sand Loam, (see Figure 4: SCS Soils Map). Wetlands Inventory There are no classified wetlands on-site. Peterson Consulting Engineers Page 10 u• m �• II ' � `' ,{l aJ��..� r� .�Q�� n _"�,t ,., '�I li ' ,...�/�nf,l). 1S'•s''�r , w�i'• k .�•I •�-: !.lSrT l�. ——, � ...r PAW.".^.� ._ - - .L1 .: -1- S IS SYMBOL NAME If" i 1 ' AL f I .,,,,.1 , hy� _ i Bit t .�., f nt s, F:v.ten ,00tw,nl• -'�. Y•I'r4 ,� Net. Beoos,te g elly,.•n•dy t•x,•„ / 1 ti, I,;— /.Q'` t.ieD Hemrs ne gra elly Bondy Irron, i , tiV p.. - + Lars •• F^ 4. •� .. Paf Beaasiie gd 01y Bondy 1-.o,n, ll n I'+, ,-.nt •.,I),x•:: A Q - INI'3Y i Bf, Bellingham s+I loom :' u ;`.,••• . •- �7r J Br Briscot silt loam B. Backley silt loam } - j �i •Bty(,�. Cb Catstol Beaches I• Ea Eorlmont silt loom Ed Edgewick fine sandy loam i h a ,tecy EvB Everett gravelly sandy loom,0 to 5 percent slopes 2s1+4 � J`• r 1i 1. EvC Everett gravelly sandy loon, >to 15 percent slopes E,D Everett gravelly sand) I nm, 1 to 30 per cent l• ...' Ew!. Everen-A lder:.orj y a -JI ,..ms F,t„ i`•tw.•.em slol I ,,-rr Q',� 'W` +•;:; ��" .- InA Indtonolo loony i,ne sand, "1 to n art slopes. °•• •AgC p= '—'�InC Indianola loomy fine sand, 4 tc 15 percent slopes 1 U Indianola loamy fine sand, I'to 30 percent elope fir' y3. I ll oIt f I ..> ` , !. -.�I f `s,,,'. Y _•rrr +� AkF ,1'r 71�.ri�'+ h __. � "i_.t. •, ,,' • i • 5 — rI► a 14ArnQ. az a:S` �R. � � •irti�� � 1. '.nI•+ I .�j �s .Ur j • j rr = Litt 11r ' SCS SOIL SURVEY MAP ERRICO SHORT PLAT SEC. 5, TWP 23 N., RGE. 5 E., W.M. D WN. B Y. DA TE: JOB NO. ro� 4030 Lake Washington ETERSON Blvd. N.E., Suite 200 BMD s/7/01 GAVE-0001 CONSULTING Kirkland, WA98033 z 1 Tel(425)827-5874 CHKD. B Y. SCALE: FIGURE: �o Fax(425)822-7216 RS N/A 4 n' Technical Information Report for Errico Short Plat Alay 17, 2001 TASK 3: FIELD INSPECTION �j A site visit was made on January 23, 2001, during a clear and sunny day. The site contains one ■ single-family residence and two sheds, with grass lawn surrounding the home and sheds. A gravel driveway serves as access to the buildings from 24"' Street. The topography of the site slopes to the west, (see Figure 2: Site Map). No visible downstream drainage problems were observed at the time of the field observation. Peterson Consulting Engineers Page 12 Technical Information Report for Errico Short Plat May 17, 2001 TASK 4: DRAINAGE SYSTEM DESCRIPTION AND PROBLEM SCREENING Please reference KC Level 1 Tables and Downstream map in Appendix"A". DRAINAGE SYSTEM DESCRIPTION Please reference the drainage system table and location map found in Appendix "A". Drainage from Basin "A" sheet flows west to the edge of the property. Where it enters a catch basin containing a 6-inch pipe. The catch basin appears to drain to the west through a 6-inch pipe under neighboring lots to the east side of Aberdeen Avenue N.E. Unable to find the end of the pipe, it is assumed it connects to the storm drainage system on Aberdeen Avenue N.E. Flow then enters Aberdeen Ave N.E. drainage system where new storm and sewer construction is m progress (point B). The new construction will divert all the flow to the north starting from the corner of 16th Street and Aberdeen. Flow will proceed to the north on Aberdeen until reaching 24th Street. Once at 24th Street, flow will then turn east for approximately 250 feet (point Q. Flow is then diverted northerly under the Kennydale Lions Park(point D) and continues in that drainage system until discharging into May Creek. No visible downstream drainage problems were observed at the time of the field investigation. t Peterson Consulting Engineers Page 13 Technical Information Report for Errico Short Plat Mav 17. 2001 IV. FLOW CONTROL AND WATER QUALITY ANALYSIS AND DESIGN The calculations are based on the 1990 King County Surface Water Design Manual (KCSWDM) requirements. The flow rates are based on the SBUH Methodology for level pool routing using the City of Renton's design standards. Precipitation 2-Year—2.0 inches 10-Year—2.9 inches 100-Year— 3.9 inches *See Appendix B or 2, 10, and 100-year isopluvials DETENTION CALCULATIONS Existing Site Hydrology The existing site runoff patterns are generally from east to west on the entire site. The slopes range from 0 - 6%, mostly flat through out the site. An existing single-family residence is located on the northern portion of the site. The ground cover consists of maintained lawn on the remaining portions of the site (see Figure 5: Existing Conditions Map). The curve numbers used for the detention calculations are based on Hydrologic Group A soils (see Table 3.5.213 in Appendix A). Total Area= 0.90 Ac (includes offsite runoff onto site) Pervious Area=Lawn - 0.79 Ac @ CN= 65.0 Impervious Area= Residence and driveway - 0.11 Ac @ CN= 98.0 Time of Concentration= 24.48 min Reach= 240.0' sheet flow @ 2%, `ns' = 0.15 Peterson Consulting Engineers Page 14 Technical Information Report for Errico Short Plat May 17, 2001 ' Flow Rates Using the existing hydrographs, the allowable release rates for the site were determined in accordance with the 1990 KCSWDM standards. The allowable release rates are as follows. 2-year Flow Rate= 0.04 efs 10-year Flow Rate = 0.07 efs 100-year Flow Rate= 0.15 efs Developed Site Hydrology The proposal is to construct 3 lots with associated roads and utilities. (See Figure 2: Site Map). Runoff patterns from the developed site will be similar to the existing conditions. The runoff from the proposed roads will be conveyed via tight line system on the west side of the property, then north to the to the NE 2e Street storm drainage system. The runoff from the roof drains will also be conveyed using the NE 241h Street storm drainage system (see Figure 6: Developed ' Conditions Map). The total area in the developed conditions needed to be detained is 0.90 acres. The site area was divided into pervious and impervious areas. The impervious area was modeled using an SCS curve number of 98 (concrete, asphalt, roofs). The pervious area was modeled using an SCS ' curve number of 68 (grass, landscaping). Total Area= 0.90 Ac (includes offsite runoff onto site) Pervious Area= Lawn— 0.63 Ac @ CN= 68.0 Impervious Area= Residence and driveway—0.27 Ac @ CN= 98.0 Time of Concentration(pervious and impervious)= 6.33 min(minimum allowed) Reach= 240.0' sheet flow @ 2%; `ns' = 0.15 Flow Rates Peterson Consulting Engineers Page 15 Technical Information Report for Errico Short Plat May 17, 2001 Using the existing hydrographs, the allowable release rates for the site were determined in accordance with the 1990 KCSWDM standards. The allowable release rates are as follows. 2-year Flow Rate = 0.11 cfs 10-year Flow Rate= 0.19 cfs 100-year Flow Rate= 0.33 cfs EXEMPTIONS DETENTION Detention does not need to be provided according to the 1990 KCSWDM (sec 1.2.3 Core ' Requirement #3 —Runoff Control). If the difference between the flow rates for the 100 year existing and 100 year developed are less 0.5 cfs then detention does not need to be provided. The difference between the flow rates for our site is 0.18 cfs (developed rate— existing rate = 0.33 — 0.15 = 0.18 cfs). Therefore no detention needs to be provided. WATER QUALITY Water quality will does not need to be provided according to the 1990 KCSWDM (sec 1.3.5 Special Requirement#5 — Special Water Quality Controls). Water quality only needs to be provided if more than 1 acre of impervious surface is being added, and our site is only adding approximately 0.17 acres of new impervious. Figure 6: Existing Conditions Map Peterson Consulting Engineers Page 16 SEC.5, TWP.23 N., RGE. 5 E., W.M. m i y N.E. 24th ST' JIJ.06 _ 2VQaaQaaaaaa N89117'09 E I80.05 + Y_ _ -. ID .�.-'.� FOUND MON --`` CASE /N .. ' 122.57 _ 0 40' rya,— ` 1 s1� x .` 5 '_Ay SCALE: 1" = 40" � ./ t ( Q. Hti^ ^ o t H I Lli O Q ��Jwl - 2W L L --J i {3 Q h V W� # 1 11 , 'ENe r 0 Q$ 15'UnL EASEMENT I Q _ = REC.NO.8908110851 ^, Wca 41 _.2 0rc � I I � _T 10'Unurr N89'13'32"E 122.55 EASEMENT i I STAMP NOT VALID EA SEMENT �o'unurr Unurr J� UNLESS SIGNED AND DATED EA -- EASEMENT }' ETERSON o '0ONSULTING I UN NE 20th ST. W NE 20th ST. — o _ h�W� Fou D MOV 4030 Lake Washington ' FIX/ND Al /N CA5E Blvd. N.E., Suite 200 O OV ,'- o IN Cps i Kirkland, WA 98033 j Tel (425)827-5874 m Fax (425) 822-7216 JOB NUMBER G711 D^'V/c_000 I FIGURE C ' SEC.5, TWP.23 N.,RGE.5 E, W.M, 6 m f � - N ` a 1 •f1 I� ,.�P - I 1 282._. T ' PTV ' MAITExiSTING WATER WATER MAIN i (TY'.)/i LINE I ,Iy� (TrP'J T I +OD ) I ✓„ ip+pp a _ _24 th S T_ n — — —s N. 12+00 1J2J 06 6+p4.6F 4 J/� N89Y17'p9.E - 9.00 �I /Y E. 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I ROM TYPE 11-54' w 4 W VANfO CRA 7E ---------- SNDE SEWER.-- CLEANouT mI 2+J1.16 ON g i (IYP.) 1 6"I£i274.6 '1 i ' ^� I ( O IK 6lE 272.6 /-1,\ I i l 1, O v I -i" I I BSBL �I I (1)BEL •DEC 2 1Lij f-WATER SERNEE.CAP ! 1 CLEANWT J m Y ( 6N FIELD T1P.LOCATION / .... .... O 0 I � � Z I I 6"IE 271.5; .-- ROOF DRAIN----- SYST I O . -——————————— - ,� pLF, I OLL EXISTING rkEE TO NN'b BE REMOVED IMPER 140US V 19'URL EASEMENT I 1. (Typ-) I I ;,j EXISTING 4,588t S.F. REC.NO.8908110851 I PROPOSED 11,868t S.F. Z I I EXISTING SIDE—SENER TO BE REMOVED I LANDRESTSCAPING IN G ' m h I I 90E fSEWER G�1n ' KIND --- ----- I 10, .._.......- I i07 I SHALL -----CONNECT HERE- ._ __..._ .... �� _ram 77 IO•UTILITY ' EASEMENT 1 EASEMENT'' _ o'UTILIrr ___ EASEMEN r S7AMPNOrVALID 8'IE 264.63 8"lE I UNLESS SIGNEDAND DATED 270.I3 • .CANNERY S E - .. CANNERY S EX.. .. SANITARY SEWER SANITARY SE"CON ' o VERIfYACTOR TO �ITRAC70R TO ETERSON V 2 8"IE 264 J3 i� NE 20th ST. '=a � SAI'7MYSE* _ NE 20th ST. o r�u .CONTRACTOR TO FOUND MDN C:O N S U LT I N G FOUND"ON h I VERIFY ..., .. ._..... IN CASE IN CASE 4030 Lake Washington 0o Blvd, N.E., Suite 200 Kirkland,WA 98033 ' m Tel (425) 827-5874 Fax (425) 822-7217218 ti W oB NUMBER BA VE-OOO 1 FIGURE n� Technical Information Report for Errico Short Plat Mav 17, 2001 V. CONVEYANCE SYSTEMS ANALYSIS AND DESIGN ' The discharge from the entire project site, plus expected upstream development, was estimated to be 0.15 cfs during the 100-year storm event. Haested Methods, Inc. computer software was utilized to determine the full flow capacity of the project's conveyance system piping at the minimum slope. The minimum pipe slope within this project is 1.0% and can convey 3.56 cfs (see ' below), the pipe can convey 20 times more than the 100-year developed storm can produce. 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W.v,..........4 ....... ...Y.4i.}}:•.,-.%v::::i::if•i::.i:.v::�:•r:'4i'-}:. }:?::::-..":�'.....:.......................r... : ....... nr ........ -,A'•rin.,.,,v .r. f 4v.,Ih U // ...,:�. yf,.r:. .r...i,. .» ...r.._-.. .., :,;.- ••.::•:--. .....v-rent .n..../... }i'..-.-.n.x......... .... ..... ...-_---....- �4yy:.{•:•??:i,ir:.F..L'ry":.::.,:�r:.::.:.....--r4.v N f-3r,,....,. -r .. ' VI. SPECIAL REPORTS AND STUDIES ' See Appendix D for geotechnical study. VII. OTHER PERMITS No permits are required at this time. VIII. ESC ANALYSIS AND DESIGN ' Several standard erosion control procedures will be utilized by the contractor to minimize the amount of erosion and sedimentation perpetuated by the construction of the site. Some of the Peterson Consulting Engineers Page 18 Technical Information Report for Errico Short Plat Mav 17, 2001 measures include a rock-lined construction entrance, filter fence, and standard ground cover practices for the temporary ditches will contain all the sediment runoff this small site gives off. A construction sequence will also be used to minimize the impacts of the construction to onsite erosion. ' IX. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION ' OF COVENANT Will be submitted after the first review. ' XI. OPERATIONS AND MAINTENANCE MANUAL The storm drainage elements requiring maintenance attention include the type 1 and 2 catch basin, storm conveyance lines, and also the detention pipe. Appendix E contains general operating and maintenance guidelines for the proposed storm drainage system. Peterson Consulting Engineers Page 19 A „ W ^ a 4/23/01 8 : 42 :5 am Peterson Engineering Consulting page 1 ' BASIN SUMMARY BASIN ID: ex02 NAME: Existing 2-year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 79 Acres 0 . 11 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 65 . 00 98 . 00 TC. . . . . 24 .48 min 6 . 33 min ' ABSTRACTION COEFF: 0 . 20 TcReach Sheet L: 240 . 00 ns : 0 . 1500 p2yr: 2 . 08 s : 0 . 0200 PEAK RATE: 0 . 04 cfs VOL: 0 . 03 Ac-ft TIME: 480 min ' BASIN ID: ex10 NAME: Existing 10-year SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . . 0 . 79 Acres 0 . 11 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 65 . 00 98 . 00 TC. . . . : 24 . 48 min 6 .33 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 240 . 00 ns : 0 . 1500 p2yr: 2 . 08 s : 0 . 0200 PEAK RATE: 0 . 07 cfs VOL: 0 . 05 Ac-ft TIME: 480 min BASIN ID: ex100 NAME: Existing 100-year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 79 Acres 0 . 11 Acres ' TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 65 . 00 98 . 00 TC. . . . . 24 . 48 min 6 . 33 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 240 . 00 ns : 0 .1500 p2yr: 2 . 08 s : 0 . 0200 PEAK RATE : 0 . 15 cfs VOL: 0 . 10 Ac-ft TIME: 480 min 4/12/01 1 : 34 : 50 pm Peterson Engineering Consulting page 1 ' BASIN SUMMARY=====_______________________ ' BASIN ID: dev02 NAME: Developed 2-year SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . . 0 .63 Acres 0 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 . 00 TC. . . . : 6 .33 min 6 . 33 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 240 . 00 ns : 0 . 1500 p2yr: 2 . 08 s : 0 . 0200 ' PEAK RATE : 0 . 11 cfs VOL: 0 . 05 Ac-ft TIME: 480 min BASIN ID: dev10 NAME : Developed 10-year ' SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 63 Acres 0 . 27 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 . 00 TC. . . . : 6 .33 min 6 . 33 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 240 . 00 ns : 0 . 1500 p2yr: 2 . 08 s : 0 . 0200 PEAK RATE: 0 . 19 cfs VOL: 0 . 09 Ac-ft TIME: 480 min BASIN ID: dev100 NAME: Developed 100-year ' SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 90 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 63 Acres . Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 988 . 0000 TC. . . . . 6 . 33 min 6 . 33 min ' ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 240 . 00 ns: 0 . 1500 p2yr: 2 . 08 s : 0 . 0200 PEAK RATE: 0 .33 cfs VOL: 0 . 14 Ac-ft TIME: 480 min • paw, PON�j Wig �, i�►�, tip, ,��� ,,,�� �.���� � 1 IVA I��sti f by 1 J Aimwift mom ON ►� �. , � ►,,� ,►. �/ ALA �LM �� • ON �..'kF . a{ PAP D L� • wA�:� � 0 Q k • Z�--;! irAW� ice' .I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL (2) CN values can be area weighted when they apply to pervious areas of similar CN's (within 20 CN points). However, high CN areas should not be combined with low CN areas (unless the ' low CN areas are less than 15% of the subbasin). In this case, separate hydrographs should be generated and summed to form one hydrograph. ' FIGURE 3.5.2A HYDROLOGIC SOIL GROUP OF THE SOILS INKING COUNTY a HYDROLOGIC HYDROLOGIC ' SOIL GROUP GROUP' SOIL GROUP GROUP* Alderwood C Orcas Peat D Arents, Alderwood Material C Oridia D ' Arents, Everett Material B Ovall C Beausite C Pilchuck C Bellingham D Puget D Briscot D Puyallup B ' Buckley D Ragnar B Coastal Beaches Variable Renton D Earimont Silt Loam D Riverwash Variable Edgewick C Salal C Everett A/B 'Sammamish D Indianola Seattle D itsap Shacar D Klaus C Si Silt C Mixed Alluvial Land Variable Snohomish D Neilton A Sultan C Newberg B Tukwila D Nooksack C Urban Variable Normal Sandy Loam D Woodinville D HYDROLOGIC SOIL GROUP CLASSIFICATIONS ' A. (Low runoff potential). Soils having high infiltration rates, even when thoroughly wetted, and consisting chiefly of deep, well-to-excessively drained sands or gravels. These soils have a high rate of water transmission. B. (Moderately low runoff potential). Soils having moderate Infiltration rates when thoroughly wetted, and consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. C. (Moderately high runoff potentiai). Soils having slow Infiltration rates when thoroughly wetted, and consisting chiefly of soils with a layer that impedes downward movement of water, or soils with moderately ' fine to fine textures. These soils have a slow rate of water transmission. D. (High runoff potential). Soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a hardpan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water transmission. 4 From SCS, TR-55, Second Edition, June 19M. Exhibit A-1. Revisions made from SCS, Soil Interpretation Record, Form #5, September 1988. r i ' 3.5.2-2 11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 3.5.2B SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1A rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY ' HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands 74 82 89 92 Meadow or pasture: i s 1'3 65 78 85 89 Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 94 ' Open spaces, lawns, parks, golf courses, cemeteries, landscaping. d good condition: grass cover on 75% uVer'opf or more of the area L-4 80 86 90 fair condition: grass cover on 50% to 75% of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, roofs, etc. 98 98 98 98 Open water bodies: lakes, wetlands, ponds, etc. 100 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion ' 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 ' 7.0 DU/GA 56 Planned unit developments, % impervious condominiums, apartments, must be computed ' commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering ' Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. 3.5.2-3 11/92 �4 W ^ 126.15 I /26.15" /26 92 /.G i7 .., 139 62.... ._-.. __ � - e^°12 SA 15 71 F' 542n P2 1 2-36 � %� 80 z �t�7L7, 4 _ 110 2 O do 01 20' 1 22 DO71. 1 2 Z ---- e - I o of ' 2 I o ------ -- :�� ' 2� I zt _ N.E. 25 J _ I I ` 2 15 7 76 I 1 1 312 "1I 33 b ° I �=� I /0/jz 57I I Z4H '� a I - -- I I, -----I---- � 0 ----III I - -- /c: ct33 - -�-f-----I R401�, � - o�II - 403 g_ Q 1 I I I I I I 1" I 3 1 I I 2 ./ lO/.33 2.3 52.3 /30 i 674/ ��p 8S/6 -15 �� � .62 60 + 7 -- - ^ 23 2 ,/ I (4 j 35 25 L 24 I� �' -�I 21 93 ry /a9 sz s� `V z9z 5 4 0 r2� o 28 � 2 W R 34 26 23 223 _ w Jl. 117, 0 33 27 c 7166 1os /s Q 22 I Q .. _ w �� ,- s Y, s) F� �s N.E. 23RD ST. o �J o `V c ` - 2 5^ eo f..� 22 �/ 4 � IK 5 T' � 21 1T ck: m r_ ESM w ^ ,f1 y3 Q 7s r�.o5 zs Q lU �' 9 2 LJ$ 31 30 /zo L11 m /,a 5 20 212M 6° ;4 I 225 Q 1 16 7B. 68.m �� /d4 61102 48z1 \v ^ ec tFA 1.6 280 N ------ z 2 1 2 Il N.E" 23RD ST 6a a 23.28 _ 1---- 1 rse7� 8 69 }-47 &,1> la'RAIN Y i 47 r FMY ,!S 09 l of Iwo I Is. I 13 14 1, /10 II 12 � a ate I 14 Q 4.6 J9.,3 /05.1 103.11 / 6. 53.07 63.Og 17 /0928 11014 _ $ N.E. 22ND $ ST./s 4 5 ti S.P. -45'78 < I o 9 8 0 m • �ti3 � R� °�. `� /74.46 /35.3J 135. I 12 v P o b (C) I !Ps m \}. 6 b N i z to 5 J4�'7 N O I 211 C/ O O I 21I33 o 2 V23 d. , = ==- r6.zz rez� z g .W7, II234 I,^ //0 a 2 210 p o % 2 2 /74.46 1.79 f/0(24tt_.la 3 21®� R 14 I' 5 50 16/26 /74.45 21 I �951.t4�s Nh 8 ,jp I -- un a N.E. Z tiW h ^ i I 4 tl of ' =. 21 0 13 4 2 01 21ST ST. � ; 9 li------ 13 N 4 .38 Z ^ fy5L24 ^e I �y 6 , n ' ;6 O II1 4� (13) ,s Ii 4L 161.26 5 I 5 25 z N 7 I. Q /5 12 -�.39 m I I.L. /l537 10� / / u�I I� ,'14 3 6 I I 6 2 I7 1 J1• mll0 71. I I I Iz6 15 - ti `n4.44 4 15 �r31 t� i 11 m (A) //. s o 7 20 5 )20p4 10 7 2 0 ` I - 14O�,V5C ZI 1, 3�R�� 10^ /l53.�J I v o "?I 'I 13 >, b, 12 -+-'1 ^' " 16 � so � 1 R m m 20 Q v _ EJM W y! ' I O V 2 I O �� J p U 2flofI 90 60 C Il0- 99.87-0 160 1 66./5 n76 78 ,� u 75.75 17444 37 r nO l �l Tu r 60 `. ?o G . .' � . 1343 I `1 1 60 96.3 /oo So /o2.s4� 16.9 St/ I /S- 59.7z I I I 19 -3 33 ,� el �4 i 11 513 11/16 1 N / 1 11,` N F9 1021. t 1901 _-- --- I IF390, I � I OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Cedar River Subbasin Name: East Lake Washington Subbasin Number: "A" Symbol t]rafnag� ra�na a Mope Datinc Ex;sttrig Potenti; I Ibservat�ons cif field �nf T Grn raertEr©r�rt sits Pobi�rr�s Pbtem� nspc#©ra resaurce Pd onion yP :► p° Name ar�d 5t�e; De;srtptian drschar a weir,or d tbevl area,aikeiRr3 ;vfrvbl er, r art:ue at�vn, °� lrr�9 :: , �: .: : cvnatr�vt+ons ur�dercapacrty pQh9 aRype.;sheetvw suvaEe,:: -:.; ,;: in i9Wditti trabilat ar or 2r%srrt overflavr pa#hv✓ays,pc3te bal�mpaats ;; nd saver< . h; f sensttty@ c�uertoPR .9 9a stream,chanri : surtace:atea area,uo�u�ne Size diameter. . desfre] tEan sr ouruhg hark slou ping 'sed�rx+erttetian.iicistorx other emsCon A Site Sheet flow 1% 0 None None No erosion exists. B Aberdeen AVE Concentrated flow n/a 150 — 300 None None No erosion exists. Catch Basin and Drainage System C 24" St NE Catch Concentrated flow n/a 300 — 550 None None No erosion exists. Basin and Drainage System D Kennydale Lions Concentrated flow n/a 550 - 1100 None None No erosion exists. Park Catch Basin and Drainage System 98-4\inBO4 W � � � � �■ � i � r i � � � � � � � � � y, v . Kind C,o«nty Drainage Basin Map CAS U m( TTLE ' - Site 5 -° i U MET »>v 1 A• 1 rn C, >U Gw SO R Z -- - NG«> •`\~! �� ' � `.. Lover ¢ _ /^�'�..,. Oa Mars 1' --='-i--`- •— -` t> '�! Tj 1. '`-,' DRAI NAB u Ww CITY Was Ilk IV/ a.. 2.' 0 i it • "POf4�. dYMOT. s ,E Iwo Ali •-'` r wW—W f �rrim rEFT ,•e WA �� m ✓4- I�t!'i�,' i i,�1\_J ���o-'i•�e� �)1 I iJr�� ��` � !J .�� y� j'�¢'"."�?-t —, . / •.�11 -� tt � _, \_ �� �BSI � I.I 7� {�\ � - ,��' 1 J 1 �Ji Frr�-1��'-_�T- �S .:;;-i y,• r / ' + 4�rs�*�t.,st � � �...� �-1.1 F �-�-�t-I f u :.i, ` t �{�' `It_.. � /i � Y.: '-• .. - _,/'. 1 } Yt 1 + #— 1 site - {' �r i_- Tom•,: I ri 'iI. 1 ���`•\`, • .� I� 1� `Imo. I !t� � I tt._�, s` / �'�il� z �� \I�sr \�f� K'� � , �• t .. R F,. •Y �� r4 .�llid(h �, Po.' �� ��1 \,4 \ -1 '1 1.1 -F: .� t \ _'� �- ,` � �� - ` fir. � .:Sy �•" 1 F I t. �i," 'K + r L�CJ y - ` T 36 F + -I \ _1 •) Landslide Hazard Duwamish Areas } g 14� ,o , r--T r�T �"". I 117 A. i_'` -- t.! t ' �"% •s - i 4 1 I 1 q\ I 1r -+ I AL :.c a `� \ .•_ �'!�. _1�I I I (1/,- �}'-. R '1 I ',� .;il f' / I 14 1 �s, Site -� I r- -t I `4t4t,L'c i��,, „•, a t�/ 1'\�'I,•�. M t T 1 i '�i t 1, �t � \ �,t •-j". � i: b � �,� Y � �1:1 �'' it ' � !" \ \ � 9 1. �J \.�• 1 k 1 C • ' ,..a.' � +,_ •` _ , I y I ,ert' t.;`� �t'`'''''gY{t.., r.]�H _.I . AA t i .. y let 71 ST n- \ l'i•.,•. /C ///��� \j s have had additional min- Wa� Mine Hazard Duwamish t recent map was filed with w n Department of Natural Re- / development that occurs Areas ea� 2' /'13 o areas should preceded x3,��1 , dy to confirm or deny the 114 itional subsurface tunnels. 9 •jqU I 12 "{-a.. 1 I I ! tX �: \`�r-••'t!; / {It I ( f i 1 - i i !/ \ `�!(;• tijt����'rl�l�.jl� ti-,-` ��✓�.i� S•. ♦. iJ � t\r� �. `�������ryy��'� 1i1-�1�1�}: 7 'rI�:'!`: �•.i .'a ti >2- f a 7 1 i- i Site r' t '' � j f-yr. �y t♦ � .T "yll •l ` i '` ` 1 J i 4 I R'it[� � :: li ... � E c .. '• fir, N .•.. , ! � I � , 1 r � - \ .�" tip% ...Rs � L ,; i. 1 •ri} - � t.j• xs'.t I II --- w `tc r. v -- — \tT is 1�•,\. Il nd landslide hazard maps forSeismic Hazard entalseismic hazard areas. DUWa1111Sf1andslide areas are susceptible 9 earthquakes. Other seismic .._ as not shown on this map are Areas 2j 13} Inderlain by Iacustrine sediments; '1 �• i ptible to liquefaction. ,g 141 $ to-- 1 6" 11- 7 2, } r;TN ^ ­. I yM u 71 .1_' t ) ' l T 1 j 1 1 ✓1 if ",j -I Sit( 'H' " _ 1 1' ]' i 1l '�: I+ ,, ,� �` z!il�}.///l ' C �'i L'i� •�f .. { V r 1 I s�� �.� �� fit_ r. �, �� ,p � •. 1 _ _ ti?�, � t •1'i a� LIM— �• J r Site t IL \ 1 4 �>ss `� +�,• t.E. !l � - \ .is. i_'1i i`1 fys.� - � �! R y :�r `�\t. ,1 °. � ` `:.,�1 _,� ,t F Poi' -�'.,, ���t'+� .1■1 ,,��� •;�{ � � �� �• 1 •. t�ky--, i _ ,y,s t>t-3 ,ham 1�- � '4f;.� /. t •.r (.rY ., �.^ '. � ,.i„{� ..r , '� -�•`,2; �• ti � 'tom+` �v � •,� i' �L.—T_ 25 ,,IM t -., � ' a�-- � a� ,� is _ ���1�•(��.)�� ,` f Erosion Hazard Duwamish Areas s �7 � ,ta • y;y IU PI17 ;. f- E 5\ >u { 1 r `\t , , .•' l ^,l f 3,�I`T:�` Al f-�'{ r r,i \��.0 7• s�l'a 4i � I I� / ,{.�, i� .. I � �- iL � �t � ��'- t�t - - AA Y C�-•`�� � •_•i�, ��' � T_— •Z �: �It / � IJI��, ��� ' la_1 4. iK\t�Y� •�.-�`�./���\�� r t w ll y Y Site - I :.:� '•- {ram :.tea. r\ `_./ � � '! �• , CAD it I, I i � .•a�t �, .�, f.,...- 1. I� \14tr. � t. } ♦t •., '. I .'1T,. � , t \-l4' � A '1 Y\1 t .� �l� � Ij tT � ��•- 9 1 1 `' ` f «1 fr •,.:�r..�, III .,#�� � / I �. }; � •1 I` ,-! ���� ... �<- ndred-year floodplains extend be. Streams and 100- -� Class 1 Duwamish else shown on maps. Hood In- t-•-t-�� Class 2(with salmonids) cc Rate Maps do not always show the _tl Ulain lit the headwaters of sl rea,r\5. Class 2(perennial;salmonid '' •mot' ' '13' Year Floodplains use undetermined) e ..:+' 3 14j • • • • • Class 3 • 5 ;10_1 ``` 100-Year Floodpiains _ _ _ Unclassified "e ai2�, Me[teCr`-,1�6uyH'k'>_'�. '_ V r �1 � I � 1'Y i r L.�1 q!t � r.tit F r * �� ,y y. "•+ '! - r t ;� 4 I 1:1" {:y. fi.'-affa�yy 34 i'krh a.. :/IS .t. .e.'.ryr Ye '' i 1 L ••t L t, ]n1 1, - {�� �i tip I ,�/1 x�• � �r�����ii� 1 ' } / ��i �I/`.. i, I /' 1 - ,/, �' �•• t• l+ < \ � i S71''{J 1 i ^L ♦!: fs'�. S :, i I �) � ��� ! J � / 11 iT,1'y(?.t.i t ". l• � i ' '"Y� lJ- 1-♦ I J t g.' .,is` 1' 1.f. l 1 t ( � '"' � �L 1. •'.{ L � 1.� `• � I�Y� _,J-1�"�'��_�{17'�1�r i��'.$� 'y��.� �i y�,r;1 �Y � l l' �I � s .. ��'.,;'�`;`b�t��`!�.!� t• � ,i-�11 ,1 c�_J - � ..`.X 1. t a fC J .{ T I I , t 'ft1a}a fL ,,� EjMcrcerlstand 1, 'I rt:,. �J�. ;!' _I 1 y C\Oal Creek f l i g 1+1 7s ! Lake t k.: 1 JI 8shg ngton I 1 f t ' tl r�• r ','1, �,,..�I ' I "' .,,r�'.;i �}�.- �.�� ��.\.... -+ 1 Jl `',` �Y..,�.s�„ ., . H `}I J�.• t.-i; •\{v �. � �„ _ _ Cam. i.: � � I f� sib. r•� � - � I r 'T�YJr�. �; � '�. ! Cam..- ! � �'� r•('�"�A ♦r � in 1,�� l�.IV � '/� - u L+e �' 1 '- F - (/fir .d f„.. �, iJ•_ � -1 d'+ k� t �1 �jY -281 • I � LL \- 1 t �.�4f� Site t - F ♦ E� ifl // v. b k iJ 3kCA'I Tf � 1t1�� 'r(�y`;'r• *t�w����M � �� ,:�{,�'Y /`f ,1-1 �T��t- �f ;, y /f I v I t + r 1 /r,, � y`f - + n►V R' l.�• Rai. r �. ,.n �:rr"-1� -a �. .. 20 r 1 W 6 21 o �: '• ' ' := per.. �•—� �I / (' bq _ s i ,` I l'J f itc s 1 :,arco wetland- e>:eept those With al: �` r�4��y'��c DuWamish •b'• designalinn are included in trle Wetlands 1Ld. s Wetlands atrly Wetlands Inveltlury llhc of Wetlands designated "a" have Open Water 2 13 'r:fied on the site by a variety of .;s. wetlands designated "U" arc i ILA 9 14 In tale U.S. Fish and Wildlife SCfI'ICC Basin Boundaries 10 ,nta IFcllands Int•errlory, but lheh luca- 6 11 tno not been field verified. Sub-basin Boundaries ay be gaps in the numbering se -111,in Ind ivI du at drainage basins. fl n wA � v r � � � � � � � r � � � i � � '� � r � Zlover Zeman Associatps,.Lqg. G:otechni4cal and Environmental Consuking J-919 February 13,2001 Skyline Properties 606— 120'11 Avinnue NE. Suite D-204 3ellovue,"Kashingtoyl 93(Y)5 Subject: Repipm of(jeotechni-cal Services Soil Assessment for Infiltration Trenches Emoo Short Plat--NE 24'h Street ReI11014 WashhIgtoll D V ear mr, Wolter: This 11.0our mport,ppesonts the results of our gcotechni4zal wit xssessment at the proposed Emzico short A:it cn NE 241h Street in Renton, Washington The purpose of our services was to assist in. soil types relative to the design and construction of stormwater infiltration ire-ne-hes. 'Mis evaluation was completed in general accordant:e with our proposal for Servikizes"No, .P-956'1 dated Airtuary 23,2001, The 1�wld li.xrk,;mbl­n for this suidy in6jded Ott;� cxc4veai-,-m of fom- (4) yc st phs in the a p"Yrtio'. of Ehe rark"Del'."V Crract A. and southi-vtst jxyrtion of Lot 2), Till approximaze ld.-Uuom of .e t­sl 'A's are Oiavvi. it, Fig-tire I Site. and Exp]OTdticni Plan). The test pits %-vere area: ed o Z ,,k as the selected infi'tratior, trench locations. The test plts U! b,, adin , cUvm l Fbu 5 200 A pti ti of ZZA ot--"A;-rv;;d 11w exC-;1-va,,Jr)ns wid ioi:g,,d soil cotiditions. Select soil sumplest -wm c-olj4cted aml to C'ur fol :es.-ilig' Tops.-cm typically torsisti',AW of loose -sand and sillty sm'.(! was t r, be:_" it "0 time I ; _1� sl- p ts. This topsoil zone extended to depths ranging i.rom 1-1-*A to approXi illa tCl V L's fmt. The soils observed 1,-)a.low the topsciii and j:hij-i t1w 3.is r,:?'...1 u-Ifil'tratior. zone. eonsist,_-d of twe principal soil types. Laose to :it "'MrO tle-iI3� ' IV n e, ura; rind wA trace to some. sitt and t-mce gravel wa.s ent;ountered in TP and'IT-4, and as an lay,r betwcen a m(-dimms%;JT Y" "".-s! 11it 1111-21. The ;,,mO -umt extended to depths of'4 an'd 4.` !Cet in test pits "rp-i I Z, L ij.,V f'1 L lovit— -anay sill was Ile prodmnnaa �. od .YPe obscr (.-Lt in tilt' CC t. p�mwncnt ecoundwater table was tintar:v cxTcr;d-,d din'-, (A' thc cycavation,s 'n t.c fV3 m tittle of.excavation, 14',tior sil-ep-.-ige was obF,,.ry ed in tillst pit'r'P- ':11­1�-.":.'z'l1' 1,1" f. Low; of the rest pits tint aliacl-,td 'to this rcpurt. 1 3 IN J-919 Geotectinival Sorviczs Feb'alary 13, 2001 Er-1co Short.Plzt Page 2 Renton.Wallu'rAVOO Portions of tfie two representative soil types recovered From the test pits were returned to out 1,aborai-o-ni for grain size; distribution testing. The results of the grain-size ainaly-ses are attached to tl ;s never", CONCLUSIO;NS AND RECOINMENDATIOINS The resides of the test pit explorations and grain size distribution testing indicate that -a layerec) Soil ho.,.cn with sand above silt is present in the proposed infiltration -areas on the )IMperty. B,,i-,:d oo the results of the groin size distribution tests, ere recomniend that the upper sand zono bo OamAfied as SA IUD according to the Unit.-Id States Department of Agriculture; (USDA) tcxtura n1mgqil.xr classification system. The lower sandy silt should be classified as SIM' LOM.1, This StUT LOAM is anticipamed to be at, 01, within 3 feet. of the base of and is c�ynqidereA the type that will contro) the infiltration � cbiracteri.s.,;c,.; u-,Jiltration trenches. \tti bt�t Vk' rec'milmend that the infiltration trenches be designed according to the King County Surf MA. No 3 ace Water Deslgr Manual based on a USDA soil type of SILT LO perrnanent groundwater table was observed in the test pits to the maximum exploration depth of 10.5 feet Wow die su.-face. We un.derstand that the base of the trenchesw-:11 be on the order of 3 to 5 feet belo-vv the Cxkt'C;1g � ;und ;surface. Ther_-R).re, it is our opinion that there will be a mininnim 3eparation of I b-ltweep. uh� bottoyn of the infiltration iTcrichcs wrid t1he pcn-nvRent grotind S F OF I HA V-i RE P, this repon for Lisse. by Sk,ylim Properties ;w.d other mel 'b proi.e;:t team )r ,Iessgru and ccnstrw,:tion of tisc propose-i swmnvau�r infiltratior, trencties at tbe E 24"" 'tree W t 'n Renton. as*.tington, This in'tot -tna tion can bQ Utilized for .r n tim- Inum.1,_4 ktl'se3siaiz Soil t cs4 infiltration trenches. Ypc.s for he d ;n of slonnwitter infi,ItT belt th". 1} td zn!.erpl'fwtatioms sbou-I'd no-I bo, onst-,ied as a warunty of the subsurface thit ofscope. ;schedule and bimlgcl., OLV services have been execated in a !y ac,..QpE­d pnwke�_,in this a-a at the Eirne the report was prepaid. No wam.nty, ­t, 'thlcr expres.;or implied,should b!'- undrentitood, ns!t Leman �sci .4r?s_inc.. (W.)77 i Y10-L W Fe,&Liary 13,2001 (,.rrico Short Mai Rclikon,wash-(ligion We trust thig miformmuc)n meets your present needs. If you have any questions or if we can bee or ffiettler please caill. Respectfully submitted, ZIPPER ZMMAN ASSOCIATES, MC. Timothy B.. Roberts, P.G. Project Engin-ler T; arnes B. Thomlmon, Pl.. Principal .-Nit:Achments: 'FigklT 1,Sile and Exploration Plan T,',,6up;t Logs(TP--.I through TP-4) r� rr r rs rr r� r► r r r r r � rr r r r` rr r� t EXPLANATION 'j"P_� •r.: :.�'ttt Rttit9bCtE►1'Ifs iit)f,4'a::twIc S(?C'2Cif]p. : 1 r LOT� f `t 1 HODU E f 1 E i [( fT f � i 'CI�.AC.T A L,S!"L:✓f.AN.`,ODJ it'll)i41101,t["V 40C M0ViDEJ B; 11T-a SON'CONSULTANTS,UNDA",'tS1 � � I i ZEINIAN 1SS0C:IATES,L'�C. i exc,3CCTNO. 1-9f9 ERRICO SHORT PLAT EZA7 F'Et3{:l RAY?4Ys RENTON,WAS1•IM+_if 0N. �:Rt� `i41F?'v"t'AL fZ3tA i4":9Y' i;!'i I TE,AND PLANT i fi:Ticu Shop r 919 IZ.�r33J7i, �� Test Pit Lug Pale t .)e t l e i ti'latarial Ue..gjp_in#1 Sample No- (YO-0.8 lk,o -w,moist, djurk brown, silty,fine St!.ND with aLrurrdalit tine roots. Lori e to medlunn derse, moist,mo►ttIcd orargc4m)-sr; tiro SAND S-1@2.5' With t.:ac a alit, 3.0-k.0 >le iiutr >tiff, inoi:;t to wet,mottled sandy SILT. _. Tcq.psi„ornpl led at 9.0 feet on 215./0 L 'qO ;'"o"rtndwater s t°page observed. Uept:h !?`;; l' .gate-nal Descrititto.i S'lp__. -oosfv, YF.4ttS:, .lt:z;l'. !'r(11'r ',, i#�ty', fin,; S-A� d.l) with :1bimilant tine root3. No 0',1-.3.11! stiff, t---wi St, mottled orange-brown,fine.SAND Nvith trace:silt, S-1( 2.11' _. +.C''•-6,1"! Med"ttni '!c-n,C', 1Ci!zSt, mottled orargQ-brrwn, fl-n SAND with 6,0-10,5 i1'tt:iltFum, `:tiff, nini:? to wet, inotdcd oral 8-2'C?6.l K, t :t (:(;ri`at) ,.._01 i}f (t..`3 i.l:Ct prjtt.fir'{;(,i.1r V-cpa.j' g-: ;)bseed at feet. I-t))9 RVATOO,WA Test Pit Lxmz Loose, moist, dark brown, ailq,., fine SANT) with ablindiult.fint.- foots, jopsoll) lla-loao Sfill" moist.Ino.alled Orange-brown to light brown, st>Lcly SILT. S-J. 4.5, et�t .pit completed, at 10.0 fee:on 1 510l. g-rcnind-water seepage observed. Ezs—tP—it M-4 -i te Material DcFcriWi(,,n S�qnp,- -th tf-;ice sil- And fibmidart -is it lul. -,A�o m.c. stiff� moi.;t, ligj'-xt brow-n,San& SIL,7L AS coutpleted at 10.5 -feet oa 2ii.M. GRAIN SIZE DISTRIBUTION ASTNI0422 �:IZE OF n-Ps-rNiNG 1PI AChES U.8,STANOARD SIEVE SIZE HYDPOMETER fy I 1J.2' IT 4 40 40 00 IM 20's ........... ........... ........... t w ce z uj ............... !wl 4 .......... 4- 4 w I till i i ' i_ _.i � '!I, }�I ti ' 1 ! ....I....... GRAIN SIZE IN MILLIMETERS Silt 1CI13Y ............ CRAVEL W 10 F!N=-�-)4AAE0 peptrl (faet) 11 wisium o,"s) .,19,; 'Q) Description ND son _trace grave!. 7JPPF-R ?P.M AN' ASS00ATE5, INC. i PROJECT NO: -Pi�19 PRO.!E(;T r-lAME; UArE OF TE-ST14G 2,'WO-1 Erna)Sho:,Plat"N'TAL 044 T 41- GRAIN SIZE DISTRIBUTIONASTIV, 0422 c;!ZF OF OP6,N'NG ftt 4 14CHES U.S.STANDARD SIEVE SIZE s HYDROMETER i.2- T r 1 117" 14- 4 i9 20 40 fij iW 2W 1()0— It ........... 4-+--- ao- i It 4 .......... 'H ............ ............... ........... cr. .17. w t -30— .......... w Ix 4 4-4. Lu 4 .......... T j; 1.00 0.10 0.01 "1 GRAIN SIZE IN MILLIMETERS ............... tkiirn AAND FINE GPAJ\W D %) 20 w 74 Sandy SILT wit): j trace qravol. N41 A IN A 3 0 C A INC NAME: ZIPPER TES-TPR�TECT 4�-7, Errk--,Sho'(1 Plat j NNIENTAL �I w tAPPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 5-CATCH BASINS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash&Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located (Includes Sediment) located immediately in front of the catch basin immediately in front of catch opening or is blocking capacity of the basin by basin opening. more than 10 I Trash or debris(in the basin)that exceeds 1/3 the No trash or debris in the catch depth from the bottom of basin to invert the lowest basin. pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outlet pipes free of more than 113 of its height. trash or debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which volume would attract or support the breeding of insects or rodents. Structure Damage to Comer of frame extends more than 3/4 inch past Frame is even with curb. Frame 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 wider than 1/4 inch(intent is to make sure cracks. all material is running into basin). Frame not sitting flush on top slab,i.e.,separation Frame is sitting flush on top of more than 3/4 inch of the frame from the top slab. slab. Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin replaced or repaired to Bottom any evidence of soil particles entering catch basin design standards. through cracks,or maintenance person judges that structure is unsound. 1 Cracks wider than 1/2 inch and longer than 1 foot No cracks more than 1/4 inch at the joint of any inlet/outlet pipe or any evidence wide at the joint of iniet/outlet _ of soil particles entering catch basin through pipe. cracks. Sediment/ Basin has settled more than 1 inch or has rotated Basin replaced or repaired to Misalignment more than 2 inches out of alignment. design standards. 1998 Surface Water Design Manual A-5 9/1/98 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 5-CATCH BASINS (CONTINUED) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed + Fire Hazard Presence of chemicals such as natural gas,oil and No flammable chemicals gasoline. present_ Vegetation Vegetation growing across and blocking more than No vegetation blocking opening 10%of the basin opening. to basin_ Vegetation growing in inlet/outlet pipe joints that is No vegetation or root growth more than six inches tall and less than six inches present. apart. Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place.Any open Catch basin cover is closed catch basin requires maintenance. Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper Not Working person with proper tools.Bolts into frame have less tools. than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 lbs.of lift;intent is keep cover from maintenance person. sealing off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs,misalignment, Ladder meets design standards Unsafe rust,cracks,or sharp edges. and allows maintenance person safe access. Metal Grates Grate with opening wider than 7/8 inch. Grate opening meets design (If Applicable) standards. Trash and Debris Trash and debris that is blocking more than 20%of Grate free of trash and debris. grate surface. >� Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets Missing. design standards. NO. 6 DEBRIS BARRIERS (E.G.,TRASH RACKS) Maintenance Defect Condition When Maintenance is Needed Results Expected When Components Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20%of Barrier clear to receive capacity the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than 3/4 inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50%deterioration Repair or replace barrier to to any part of barrier. design standards. 9/1/98 1998 Surface Water Design Manual A-6 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 7- ENERGY DISSIPATERS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Components Maintenance is Performed. External: Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design Rock area five square feet or larger,or any exposure of standards. native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that it Sediment design depth. matches design. Not Discharging Visual evidence of water discharging at Trench must be redesigned or Water Properly concentrated points along trench(normal condition rebuilt to standards. is a"sheet flow"of water along trench). Intent is to prevent erosion damage. Perforations Over 1/2 of perforations in pipe are plugged with Clean or replace perforated pipe. Plugged. debris and sediment. Water Flows Out Maintenance person observes water flowing out Facility must be rebuilt or Top of"Distributor" during any storm less than the design storm or its redesigned to standards. Catch Basin. causing or appears likely to cause damage. Receiving Area Water in receiving area is causing or has potential No danger of landslides. Over-Saturated of causing landslide problems. Internal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to 1/2 or Replace structure to design Post.Baffles,Side original size or any concentrated worn spot standards. of Chamber exceeding one square foot which would make structure unsound. Other Defects See"Catch Basins"Standard No.5 See"Catch Basins"Standard No. 5 1998 Surface Water Design Manual 9/1/98 A-7 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 10-CONVEYANCE SYSTEMS (PIPES & DITCHES) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sediment diameter of the pipe. and debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged; rust is causing Pipe repaired or replaced_ more than 50%deterioration to any part of pipe. Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%. Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through through ditches. ditches. Erosion Damage to See"Ponds"Standard No. 1 See"Ponds"Standard No. 1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design Place or Missing(If the rock lining. standards. Applicable). Catch Basins See"Catch Basins:Standard No.5 See"Catch Basins"Standard No.5 Debris Barriers See"Debris Barriers"Standard No.6 See"Debris Barriers"Standard (e.g.,Trash Rack) No.6 NO. 11 -GROUNDS(LANDSCAPING) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growing in more than 20%of the landscaped Weeds present in less than 5% (Nonpoisonous) area(trees and shrubs only). of the landscaped area. Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation vegetation. present in landscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter. within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than broken which affect more than 25%of the total 5%of total foliage with split or foliage of the tree or shrub. broken limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of knocked over. injury. Trees or shrubs which are not adequately supported Tree or shrub in place and or are leaning over,causing exposure of the roots. adequately supported;remove any dead or diseased trees. 1998 Surface Water Design Manual 9/1/98 A-9 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 12-ACCESS ROADS/EASEMENTS Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which square feet i.e.,trash and debris would fill up could damage tires. one standards size garbage can. Blocked Roadway Debris which could damage vehicle tires(glass Roadway free of debris which or metal). could damage tires. Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet high. Any obstruction restricting the access to a 10 to Obstruction removed to allow at 12 foot width for a distance of more than 12 feet least a 12 foot access. or any point restricting access to less than a 10 foot width. Road Surface Settlement, Potholes, When any surface defect exceeds 6 inches in Road surface uniformly smooth Mush Spots,Ruts depth and 6 square feet in area. In general,any with no evidence of settlement, surface defect which hinders or prevents potholes,mush spots,or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are Road surface free of weeds taller Surface more than 6 inches tall and less than 6 inches than 2 inches. tall and less than 6 inches apart within a 400- square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disposal Pavement petroleum hydrocarbons. in keeping with Health Department ' recommendations for mildly contaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches hinder maintenance access. in height or cleared in such a way as to allow maintenance access. i 9/1/98 1998 Surface Water Design Manual A-10 e