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Prelim Storm Drainage 01-29-07i ' ~RE~IMINARY STORM DRAlNIAGE REPORT Yelm RV/Boat &Mini-Storage 1 Between Crystal Springs Road S.E. and Rhoton Road S.E. Yelm, Washington RE~~-VED FEE ~ 5 2007 ~~. n ~~`~ d Prepared for: Randy Weber 25720 - 217th Avenue S.E. Maple Valley, WA 98038 January 29, 2007 Our Job No. 72433 GHAG `'1-I~ ~Z ~~ ~ ci y Rr~','z~~ ? s~< ~1 U-, ~g, ~,Nr' ENGIN~~ CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 FAX BRANCH OFFICES • OLYMPIA, WA • TACOMA, WA • SACRAMENTO, CA • TEMECULA, CA www.barghausen.com } TABLE OF CONTENTS 1.0 PROJECT OVERVIEW Figure I -Vicinity Map Figure 2 -Soils Map 2.0 EXISTING CONDITIONS SUMMARY AND ANALYSIS OF REQUIREMENTS 2.1 Analysis of the Minimum Requirements 3.0 OFF-STTE.ANALYSIS 3.1 Study Area Definition 3.2 Upstream Drainage Analysis 3.3 Field Inspection 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrology C. Performance Standards D. Flow Control System E. Water Quality System F. Conveyance System Analysis and Design 5.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN 6.0 SPECIAL REPORTS AND STUDIES 7.0 OTHER PERMTI'S 8.0 OPERATIONS AND MAINTENANCE MANUAL 9.0 BOND QUANTITIES 12433.OOI.doc ' 1.0 PROJECT OVERVIEW The proposed Yelm RVBoat &Mini-Storage development has a gross site area of 7.57 acres located in a portion of the Northwest quarter of Section 19, Township 17 North, Range 2 East, Willamette Meridian, City of Yelrn, Washington. More specifically, the project is located west of Rhoton Road S.E. and to the east of Crystal Springs Road. Please refer to the vicinity map (Figure 1) for a more accurate depiction of the project location. The proposed Yelm RVBoat &Mini-Storage project proposes to construct 11 storage buildings and an associated office building. The development will include RV parking spaces on the south and west sides of the site. In addition, frontage improvements on the west side of Rhoton Road S.E. will include a 7-foot landscaping strip and a 5-foot concrete walk. The project proposes to infiltrate stormwater runoff through a series of infiltration trenches. Stormwater treatment will be provided for the parking lot runoff through VortSentry Manhole ' filtration units. All stormwater facilities will be designed in accordance with the City of Yelm and the 1992 Department of Ecology Stormwater Management Manual. G 1 12433.OOl.doc 1 1 1 1 1 1 1 1 1 1 1 FIGURE 1 VICINITY MAP Scale: Horizontal: N.T.S. 4 ~ n-`stn m Z ,~ - o i <r~ 1 se MQ ENC~Ng Vertical: N/A 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES P:112000s1124331exhibitlstorm drainage112433 vmap.cdr For: Job Number YELM RV/BOAT &MINI-STORAGE 12433 YELM, WASHINGTON Title: VICINITY MAP DATE: 1 /17/07 REFERENCE: Thomas Guide (2006) FIGURE 2 SOILS MAP REFERENCE: USDA, Natural Resources Conservation Service LEGEND: 65 =McKenna gravelly silt loam, 0-5% slopes 110 =Spanaway gravelly sandy loam, 0-3% slopes 113 =Spanaway stony sandy loam, 3-15% slopes Scale: FOI:' Job Number Horizontal: N.T.S. Vertical: N/q YELM RV/BOAT &MINI-STORAGE 12433 ~,Ha V 18215 72ND AVENUE SOUTH YELM, WASHINGTON 4 ~-- stn KENT, WA 98032 m Z (425) 251-6222 Titl@: _~ (425) 251-8782 THURSTON COUNTY y°p<r~~AV 60° CIVIL ENGINEERING, LAND PLANNING, ~ha g„G~N6' SURVEYING, ENVIRONMENTAL SERVICES SO I L S U RVEY MAP DATE' 1!17/07 P:112000s1124331exhibitlstorm drainage112433 soil.cdr 2.0 EXISTING CONDITIONS SUMMARY AND ANALYSIS OF REQUIItEMENTS 2.1 Analysis of Minimum Requirements Minimum Requirement No. 1: Preparation of Preliminary Storm Drainage Report. ,~ Response: This Preliminary Storm Drainage Report has. been prepared in accordance with the 1992 Washington State Department of Ecology (DOE) Stormwater Management Manual for the Puget Sound Basin. Minimum Requirement No. 2: Construction Stormwater Pollution Prevention (SWPP). ' Response: A SWPP Plan is not required since the project proposes to infiltrate all Stormwater from the site. Minimum Requirement No. 3: Source Control of Pollution. Response: There are no required source controls for this project. Minimum Requirement No. 4: Preservation of Natural Drainage Systems and Outfalls. Response: The Stormwater from the site will be infiltrated on site as in the pre-existing condition. Minimum Requirement No. S: On-Site Stormwater Management. Response: A series of infiltration trenches have been designed to infiltrate the 100-year developed storm. ,. Minimum Requirement No. 6: Runoff Treatment. Response: VortSentry manhole filtration units will be used on site to meet runoff treatment requirements. Minimum Requirement No. 7: Flow Control. Response: This project is proposing drainage facilities that will retain and infiltrate Stormwater runoff in accordance with the 1992 Stormwater Management Manual for the Puget Sound Basin methodology. Minimum Requirement No. 8: Wetlands Protection. 1 Response: There are wetlands adjacent to the development, but they will not be disturbed. Minimum Requirement No. 9.• Basin/Watershed Planning. Response: No special basin watershed planning is necessary for the site. 12433.OOl.doc Minimum Requirement No. 10: Operation and Maintenance. Response: An operation and maintenance manual consistent with the provisions in 1992 Stormwater Management Manual for the Puget Sound Basin will .be provided for all proposed stormwater facilities and BMPs. ,7 ' 12433.OO1.doc .. 3.0 OFF-SITE ANALYSIS . 3.1 Study Area Definition The enclosed Figure 1 (Vicinity Map) shows the location of the proposed development. The site has relatively moderate slopes with a high point near the center of the site. Stormwater on the eastern portion of the site drains eastward into a ditch on Rhoton Road S.E. Stormwater on the Western portion of the site drains to Yelm Creek, which is located approximately 200 feet west of the proposed development. 3.2 Upstream Drainage Analysis ,' Based on the site visit, there is very little upstream drainage onto the site. Runoff from the east is captured in the existing ditch on Rhoton Road S.E., and the upstream runoff, if any, from the -south and west is captured in Yelm Creek. 3.3 Field Inspection There were no problems that were reported or observed during inspection of the site. Based on the site investigation and general knowledge of the area, there are no known erosion or flooding problems that will occur, or be aggravated as a result of this development. f 12433.00 l.doc I J .,-~ GGU I VV tan _ t ''~ I M UN AI ARE CO RT ~ 2 ~ 1 2 38 4 S 6 aS-BB 63008272 ~ r'~ ~ 210 00 1 r_ ,- _ i ssem n zlo3oo a' ~~ ~,~ 219'900 i 220103 ! - SS008255YL 210600 ~ 3 AKERS ADDITION t , ' 3 210800 ®203 r a s' ~ , 33 a 3 a I z+aas' I a~ 5 1 e ~ a s G 5 ~ MCF 0204 220600 i a r ,B t ! B ~ ~ ,6 210403 0 5s6o36 210404 i 220700 , 3 t ~, ~~ 8 .220205 ~ „ ,a ,3 ,a ,5 i I i 5 6 ' 23'0204 I , ~ IE I ~ BLA ~ ~~ S7- 6 s 230205 ~ 240101 `037 240100 230400 6 I B SPAEN ~ I co9lF 0 { t6 ] ; `\ 3 w~/ G~ I s z SITE 240203 i10 2 // ' _ . t a 6 ~ ; 240200 2ao2o1 ' ' ~ z3ozol 230100 ~ \ 240202 i ~ ~ i ~ i ~] 6 ~ I / ' , ~ ~'~. 232400 ~ / / . „b ~ i i O.h_~+ 231201 z3o,o] 1 i ~' 240300 i ,' \ ~ i /i/ /i sF.._ ~ i ~ \ \ i /. \ ~! \ `Ry t ' / MC KENNA IRRIGP 231200 ! a 240600 ~~ 240500 / ss-6m, \ / ~ ,2 ' ,~ 310200 // /~ _._._._._._._.__._._. ~tRiNNPN -- --+.o i~'• 310100 \\ ~yJ~~./ t \ \ P. z 11 z0,00 ~~\ '~ ~ 3 t8 \ ~\~i' y'` t 3 ;.\ , ~ ° ~4, ~ 5 / i ~ t ~ \ e o ~ \ \~ 310300 / ' FOP SS028304 6 ' ~3® ; + /FF 00500 \ toso ~.~' s's1~$63 / /! o B n / ] ofz •. \~\ i \C~O~ i 316603 ~ < / t5 C t ,9 50 /' 6 6 \ ~ / / 3101404 / / / \.~,T 3 ~! O \ i3 to x. i] ~ \ ~ / 5 \~(f~ B ' /' { 18 ~(K 00200 ~G M a a i '\ 30 60 ~. / / , a,oaos hk~' 010 ~ ~ \ \ i a x, ,0 9 /;~ \"~j~ 2 t 0Q~ g300 /C`"' 00300 /'/~.\ ~X'/ .t ~'a~ y \ II 1 i~~CC` O ', \ i' , a: '\.\ ~ t ~O t ~'~'/ ' \\~L"QQt 5i'~ 00300 ~.•\ x, i ,~. ~ . , t , 2 ~, \'R( fitA-8033 t 2 /~~ f0 a/~/~~\ Ot000 6 ~ ]o '~ \~ ^ tt s /a0o1o0 \~ \ 3 , .' / // \~'FRo 0 _ ~C'~'~ // /.\Y+a 0. i' . / 3 ~ \~ o REFERENCE: Thurston, Washington Map ID: 17-2E-19 Scale: Fp/° Job Number ' Horizontal.• N.T.S. VeRical: N/A YELM RV/BOAT &MINI-STORAGE 12433 GH'gV 1821572ND AVENUE SOUTH YELM, WASHINGTON ~ -j `4F KENT, WA 98032 ~' ~. Q1 ` Z (425) 251-6222 Title: ~ ;'~ _ (425) 251=8782 ASSESSOR MAP . ~~ '~~'W\ ,. <r ~ 6p CIVIL ENGINEERING, LAND PLANNING, ~N~ eNO,Ng SURVEYING, ENVIRONMENTAL SERVICES DATE: 1/17/07 P:112000s1124331exhibitlsto7m drainage112433 amap.cdr 1 . ~`~" ~~~' LEGEND , y FLOODWAY AREAS•IN ZONE AE ~q' ~ ~ Q ~c`P~ T~~Y a OTHER FLOOD AREAS A~ SJ. 9 ZONE X Areas of SW-year flood; areas of 100-year 4 ~c~ Flood with average depths of less than 1 foot or ~ with drainage areas less than 7 square mile; ,~ ~, $ '~ c and areas protected by levees- from 100-year fl d L,_ t ,~r~ `~ oo . ~ A ~~~' OTHER AREAS ZONE X Areasdeterminedtbbeoutside500.yearflood- sp9~ Sri ~~ plain. REFERENCE: Federal Emergency Management Agency (Portion of map 530310 0001 A -June, 1999) Vertical: N/A 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES Scale: Horizontal: N.T.S. ~GHAv~ ~ ` ~~ Z +~ - c _ u s ~a° i ~r~'vc eNaNebo- Fp/° Job Number YELM RV/BOAT &MINI-STORAGE 12433 YELM, WASHINGTON Title: FEMA MAP DATE: 1 /17/07 P:112000s1124331exhibitlstorm drainagel12433 fema.cdr ""!,._~`,. ~ ;,fit :., <~z ~Pumi _-~ --~.. `~ gar..,-- -,._.;': "~`, _ E~---- _ , sew , o ;1 i ~q .y's I _. I~ ~ ~ •( ~' ~~~ ' ~ Mo: _' • '' ~ ~ • ~ • Pd't 2 ~ ~ I _ - ._ ~~ ' r _ y~ ~I ~~~~ 181~Ctiy_ _ ~ ~ saa .--~ ~~ I29 ~ __ ' .- ~ .. ' _~ ~ '~ ~~`.'- - _ `v ' ~, - Gotl Cours 1 ` ` ~ • ~ Saltier - ~` - _ --l=aloe ~'; i'~`` t' ~ ~=---~ ~ •- -~` !,;~ ~ `1; -- . is ~ ,-- - ~~ ~ ~'`- J ~'J~~ i s `~". ~. 1 .~,-_- r , ~. ..,_, REFERENCE: www.topo.com (2006) Scale: Horizontal: N.T.S. Vertical: N/A ~HA U ~ S 18215 72ND AVENUE SOUTH 4 nI" ~ KENT, WA 98032 m ' Z (425) 251-6222 o ,~ (425) 251-8782 ? _~ ~ ~~ p~r l ~p°~ ' ~ CIVIL ENGINEERING, LAND PLANNING, ha eNO~a ' SURVEYING, ENVIRONMENTAL SERVICES I- •' • ... .t:~ - . . , ~~ 2f1 c. _1 • 'f~29 ~' ~`~% ~~ ~"`;/ ---' /-p/° Job Number YELM RV/BOAT &MINI-STORAGE 12433 YELM, WASHINGTON Title: TOPOGRAPHIC MAP DATE: 1 /17/07 P:112000s1124331exhibitlstorm drainage112433 topo.cdr t ~`4 I J aye REFERENCE: Thurston County Map Scale: Horizontal: N.T.S. Vertical: N/A GHAV ~ 18215 72ND AVENUE SOUTH ~ ~-/ ~ KENT, WA 98032 Q~ - ~ Z (425) 251-6222 0 0 (425) 251-8782 =p ~ gp°~ ~<r , 6 ~ CIVIL ENGINEERING, LAND PLANNING, '~'6 g,q G~N SURVEYING, ENVIRONMENTAL SERVICES P:112000s1124331exhibitlstortn drainagel12433 sens.cdr :, ,./~r +~~ ~ Parcels , .. ~ ,5 ~' ., ;~,` ~ ,..;:;. Roads Stnaams Watei 13od~s Wetlands _ 2+J05 Aerial Phoios (-pJ'; Job Number YELM RV/BOAT &MINI-STORAGE 12433 YELM, WASHINGTON Title: :~ _ _~ SENSITIVE AREAS MAP DATE: 1/17/07 1 - __ 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ~, A. Existing Sate Hydrology The site is currently covered with pasture and trees. The site has relatively moderate slopes on the developable portion of the site ranging from 0 to 3 percent. The site has a high point near the center of the site. Stormwater on the eastern portion of the site drains eastward into an existing ditch on Rhoton Road S.E. Stormwater on the western portion of the site drains to Yelm Creek. B. Develo ed Site H drolo P Y gY Stormwater runoff from the roofs will be tightlined directly to infiltration trenches through either an 8-inch or 6-inch drainpipe. Runoff captured from the parking lot will be conveyed to VortSentry water treatment manhole units prior to the infiltration trenches. C. Performance Standards The 100-year developed storm event will be infiltrated on site in a 24-hour period. The infiltration rate used to design the trenches is 20 inches/hour. D. Flow Control System The developed 100-year storm event will be infiltrated on site. The 1992 Stormwater Management Manual for the Puget Sound Basin methodology was used to meet the volume retention design requirements. . E. Water Quality System Eight VortSentry water treatment manhole units have been proposed to treat pollutants. F. Conveyance System Analysis and Design Runoff from the site will be captured in a series of catch basins and roof drains and tightlined to the proposed infiltration trenches. The conveyance system will be designed to pass the 100-year storm according to 1992 Stormwater Management Manual for the Puget Sound Basin. 12433.OO1.doc Page 1 of 2 Appended on: 16:26:23 Saturday, January 06,,2007 LPOOLCOMPUTE [DUMMY] SUMMARY using Puls Start of live stora e: 3LtS.000U tt Event Match Q (cfs) Peak Q (cfs) Peak Stg (ft) Vol (cf) Vol (acft) Time to Empty 100 year 0.0000 0.1389 328.6968 209.05 0.0048 24.50 Running P:\\12000s\\12404\\engineering\\STORMSHED\\DUMMY Report.pgm on Saturday, January 06, 2007 Summary Report of all Detention Pond Data Event Precip (in) 2 year 2.5000 10 year 3.5000 100 year 5.0000 BASLIST2 [DEVELOPED] Using .[TYPE 1 A] As [ 100 year] [DEVELOPED] Using [TYPElA] As [100 year] LSTEND Peak Q Peak T Peak Vol (ac- Area BasinID Event (cfs) (hrs) cf) (ac) Method/Loss Raintype PEDII 100 I I 0.2693 I I 7.83 0.0855 II 0.23 II SBUH/SCS1~ElA EVELOPEDII 100 II 0.2693 ~~ 7.83 BASLIST [TYPElA] AS [100 year] DETAILED [DEVELOPED] LSTEND Record Id: DEVELOPED 0.0855 II 0.23 II SBUH/SCS IITYPEIA Design Method SBUH Rainfall type TYPE 1 A Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 0.00 ac~ DCIA 0.23 ac Pervious CN 0.00 DC CN 95.37 Pervious TC 0.00 min DC TC 2.80 min Directly Connected CN Calc Description SubArea Sub cn file://P:\12000s\12404\engineering\STORMSHED\12433INFILTRATION .html 1/22/2007 Page 2 of 2 Impervious surfaces (pavements, roofs, etc) I 0.23 ac 98.00 DC Composited CN (AMC 2) 98.00 Directly Connected TC Calc Type Description Length Slope Coeff Misc TT Sheet Smooth Surfaces.: 0.011 150.00 ft 1.00% 0.0110 2.00 in 2.80 min Directly Connected TC 2.80min HYDLIST SUMMARY [ 100 year out] LSTEND HydID Peak Q (cfs) Peak T (hrs) Peak Vol (ac-ft) Cont Area (ac) 100 year out 0.1389 7.67 0.0855 0.2300 STORLIST [INFILTRATION] LSTEND Record Id: INFILTRATION Descrip: Prototype Record Increment 0.10 ft Start El. 328.0000 ft Max El. 330.0000 ft Length 60.0000 ft Width 5.0000 ft Length ssl O.OOv:lh Length ss2 O.000Ov:lh Width ss 1 O.OOv: l h Width ss2 O.000Ov: l h Only consider bottom area for infiltration DISCHLIST [INFILTRATION] LSTEND Record Id: INFILTRATION Descrip: Prototype Structure Increment 0.10 ft Start El. 328.0000 ft Max El. 330.0000 ft Infiltration rate 20.0000 in/hr WP Multiplier 1.00 Licensed to: Barghausen Engineers file://P:\12000s\12404\engineering\STORMSHED\12433INFILTRATION .html 1/22/2007 ,~ ~-~ `, ~~~ .'~ ~. \ '~. ~:° >, ~r ~_ >: ~; ~~ No. I Date By Ckd. Appr. I Revision Job Number Scale: ~.G'F~q~~1 18215 72ND AVENUE SOUTN Designed CRJ T1tI6: 12433 m~' i ~`~ K4 NT, WA-98032 Drawn CRJ CATCHMENT AREAS Horizontal ( 25)25 6222 Checked CMV 1 =100 Sheet ~ . ~ (425)251-8782 FAX °y ? Approved HPCi Vertical For: `~~, 5' CIVIL ENGINEERING, LAND PLANNING, <r,~c ~~~ suRVEYINC, ENVIRONMENTAL sERVICES Date1 19 07 YELM MINI-SELFSTORAGE + BOAT/RV 1 of 1 ENG\N . EXPLANATION OF CALCULATIONS Void Ratio: 40% Volume of Runoff per 10000 SF (see highlighted 209.05 CF portion of attached calculations) Trench Surface Area Required per 10000 SF 300 SF Trench Depth: 2 FT Trench Width for building roof runoff: 5 FT Trench Width for parking lot runoff: 10 FT Sample Calculation: Parking. Lot Trench: Trib Area 12000 SF Void Ratio 40% Trench Width 10 FT Trench Depth 2 FT Volume Required = (12000SF / 10000 SF) * 209.05 CF = 250.86 CF Area Required = (12000 SF /10000 SF) " 300 SF = 360 SF Length = (360 SF / 10 FT) = 36 FT Volume Provided = 36 FT * 10 FT ` 2 FT '` .40 = 288 CF YELM MINI-SELFSTORAGE 8~ BOAT/RV 3#:12433 1 /15/2007 TRENCH VOLUME NEEDED PER 10000 SF: 209 CF rTRENCH AREA NEEDED PER 10000 SF: 300 SF VOID RATIO: 40% CATCHMENT AREA AREA VOL REQ. AREA REQ. (SF) 1 11250 235 337.5 2 8969 187 269.07 3 5101 107 153.03 4 6110 128 183.3 5 4816 101 144.48 6 10864 227 325.92 7 5004 105 150.12 8 4379 92 131.37 9 4239 89 127.17 10 10275 215 308.25 11 4022 84 120.66 12 3772 79 113.16 13 3748 78 112.44 14 9186 192 275.58 15 6989 146 209.67 16 5769 121 173.07 17 5839 122 175.17 18 14144 296 424.32 TRENCH REQUIREMENTS DIMENSION TRENCH DESIGN TRENCH TR1B. AREA AREA (SF) VOLUME REQ. (CF) L W AREA PROV.(SF) VOL. PROV. (CF) 1 (15-18) 32741 982 684 100 10 1000 800"' 2 (7-14 44625 1339 933 135 10 1350 10f30" 3(1-6) 47110 1413 985 145 10 1450 1160 ' YELM MINI-SELFSTORAGE & BOAT/RV JOB#: 12433 1 /15/2007 TRENCH VOLUME NEEDED PER 10000 SF: 209 CF ' TRENCH AREA NEEDED PER 10000 SF: 300 SF VOID RATIO: 40% BUILDING AREA VOL REQ. (CF AREA REQ. SF) A 4500 94 135 B 9350 195 280.5 C 11950 250 358.5 D 9800 205 294 E 3400 71 102 F 3200 67 96 G 3200 67 96 H 3400 71 102 I 10700 224 321 J 11950 250 358.5 K 10700 224 321 OFFICE 1050 22 31.5 TRENCH R EQUIREMENTS DIMEN SIONS TRENCH DESIGN TRENCH TRIB. AREA AREA SF) VOLUME REQ. (CF L W AREA PROV. SF VOL. PROV. (CF) BACK B 4675 140 98 30 5 :> 1.50. ,:,~ ~;1.20',~' -<- B&C 10650 320 223 70 5 351 281; C&D 10875 326 227 72 5 ~ 359 ` ' '' V'?87`-~:~' T''` D,E,&F 9900 297 207 65 5 ~_~ 327. ~-r; ,.261,.. -.:. I, G,&F 10150 305 212 67 5 335 `268=' I&J 11325 340 237 75 5 '+,. _ 374; w; ~ ;~299,~; ';:d J&K 11325 340 237 75 5 37~ _ ,299~,,, BACK K 5350 161 112 35 5 ~'~ ~ ~'' 177 ~' ~ ~ ~ ~:~`1~41 ~ ~- -"~ H 3400 102 71 22 5 ;~, 1 1.2 ,gp ; ~; ~._- A,OFFICE 5550 167 116 37 5 1 g3 147 1 S.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN A Construction Stormwater Pollution Prevention Plan is not required since the project proposes to infiltrate all runoff. 1 12433.OO1.doc 6.0 SPECIAL REPORTS AND STUDIES The following special reports and studies are included: • Preliminary Infiltration Evaluation prepared by Earth Solutions NW LLC dated November 16, 2006 12433.OO1.doc n November 16, 2006 ES-0632 Mr. Randy Weber c% Thomas Construction 23713 Southeast 264th Street Maple Valley, Washington 98038 Subject: Preliminary Infiltration Evaluation Proposed Yelm Self Storage ' Crystal Springs Road Northwest Yelm, Washington l Z ~3~ ., Earth Solutions NW L.LC • Geotechnical Engineering • Construction Monitoring • Environmerital Sciences Dear Mr. Weber: '` -'' As requested, Earth Solutions NW, LLC (ESNW) has prepared this letter summarizing our preliminary infiltration evaluation for the subject site. ' Project Description We understand plans include developing the subject site with a self storage facility and associated improvements. Runoff generated from site development will be directed to a storm pond located in the northwestern portion of the site and will be allowed to infiltrate into the :underlying native soils. We anticipate grading will be relatively minimal, with cuts and fills of less than five feet required to achieve design elevations. If the move design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this letter. A representative of ESNW was on-site on September 28, 2006 to explore subsurface soil and groundwater conditions at locations within the proposed storm pond area and general development area of the property. Our fieldwork consisted of observing and fogging a total of four test pits and performing textural analyses of representative soil samples. 2881 152nd Avenue NE • Redmond, WA 98052 • (425) 284-3300 • FAX (425) 284-2855 • Toll Free (866) 336-8710 Mr. Randy Weber ES-0632 c/o Thomas Construction Page 2 November 16, 2006 ': SITE CONDITIONS Surface The site is located in the east of the .intersection. of Crystal Springs Road Northwest and Coates ' Street Southeast in Yelm, Washington. The subject site is roughly rectangular in shape, and is bordered to the north and south by developed parcels, to the east by Rhoton Road and to the west by Crystal Springs Road Northwest. Topography across the site relatively level, descending very gently to the west leading to the Yelm Creek. The site is largely vacant and vegetation throughout the majority of the site consists of field grass, with sparse trees. ' Subsurface We excavated three test pits within. the proposed storm pond area and one in the general area of site development and we have attached the field logs to this letter for reference. The soils at our test sites consisted primarily of loose to medium dense poorly graded sand and gravel (Unified Soil Classification SP-SM and GP) recessional outwash deposits. The available eolo is ma of the area identifies recessional outwash ravel Q o throu hout the 9 9 p 9 ( 9 9) 9 site and surrounding areas. The Thurston County SCS map indicates the majority of the site is 'nderlain by outwash deposits (Map Unit 110, Spanaway gravelly sandy loam). The soil conditions observed at our test sites generally correlates with the geologic map and soil survey designations. ' Groundwater No groundwater was observed at the time of our fieldwork (October 20, 2006) at our test sites located within the proposed storm pond area which were advanced to a maximum depth of ten feet below existing grades. We understand that previous exploration .pits excavated during record- breaking precipitation in 2005 were observed to have standing water at a depth of approximately five feet below existing grades. In our opinion, based on the soil and groundwater conditions encountered during our fieldwork (October 2006) the previous standing water was likely perched and may have been partially confined by excavated and disturbed soils. In our opinion the past standing water conditions do not reflect the overall site soil drainage characteristics nor does it represent the seasonal groundwater table. However, groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity; the time of year, and soil conditions. In general,. groundwater flow rates are higher during the wetter, winter months. ,~ '. Earth Solutions iVW, iLC i Mr. Randy Weber ES-0632 c/o Thomas Construction Page 3 ' November 16, 2006 ' PRELIMINARY INFILTRATION EVALUATION Our infiltration evaluation consisted of textural analyses of representative soils to assist in ' characterizing the soils to provide appropriate design infiltration rates conducted in accordance with the 1992 DOE Stormwater Management Manual. Our test sites were located within the proposed infiltration pond area. Textural Analyses ' Textural analyses were performed on representative soil samples collected from the test sites at variable depths. The textural classifications were performed in accordance with the USDA sieve method. This classification differs from the USCS classification method in that the sand fraction of ' the sample is based on the minus #10 sieve fraction as opposed to the minus #4 sieve fraction used for USCS classification. ' The native till soils encountered in these test pits consisted of extremely gravelly sandy loam, extremely gravelly loamy coarse sand and extremely gravelly coarse sand, based on the USDA textural classification. ' Infiltration Recommendations ' :n our opinion, based on the soil and groundwater conditions observed at our test sites and the "results of our laboratory analyses, an infiltration rate of 20 inches per hour can be used for design. This rate is relatively conservative given the coarse nature of the soils encountered during our ' fieldwork. No groundwater was observed at ~ the time of our fieldwork (October 2006). However, designs should provide a minimum of three feet of separation between the pond bottom and the .seasonal high water table. Due to the lack of a groundwater table within the upper approximately ten feet of the site soil deposits, in our opinion the pond bottom can be situated at a maximum depth of seven ' feet below existing grades. A representative of ESNW should observe the final infiltration elevations to see that soil conditions ' are as anticipated. Based on conditions encountered, modifications to the infiltration design may be necessary: LIMITATIONS The recommendations and conclusions provided in this infiltration evaluation are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions m this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test sites may exist, and may not ..become evident until construction. ESNW should reevaluate the conclusions in this infiltration `valuation if variations are encountered. Earth Solutions tJVV, LLC Mr. Randy Weber ES-0632 c/o Thomas Construction Page 4 November 16, 2006 -- We trust this letter meets your current needs. If you have any questions or require additional `~ information, please call. Sincerely, EARTH SOLUTIONS NW, LLC ' ~~, el, , Project Geologi ' ~ R. CA,t,~ -lam aF w~sy, eE` y' ~~ -~ '~ ,p~~ ~ -~SIFx~ ~t)1b~o6 Kyle R. Campbell, ~~~' ' Principal txr~a ~ ~ ~ - 9~ a8 Attachments: Plate 1 -Vicinity Map Plate 2 -Test Pit Location Plan Test Pit Logs ~~) ' Earth Solutions MN, LLC 857H LW SF ~!~ COUi~'TY ~ j esTl; alp s~ - - -- 89fN AV SF I ~~t--- 84T;~i o = Ai( SC i #OL{y_ RCRRiC~ C7 sE cT sr` o ` oanrrAV __ _ CARLA ° c``.~A Sf - CT S[ o `~4' `~ '~ h ~~ U 2 rd~.Ri~.t3- ~; - -- -- _- t^ ;: ~ -- - - --- ~_ - -- s~ ~ ~ CANA: Ri, I ~\ a - lift ti': El! c r DR S` aixt ~ U2 tiF O I - CRVSTAL nf~rs~¢: /. 9380 AV SE 5'Rr.GJF - ' `c. „ :~ -. C? Sv, ~, z s: o CJF=ia RI-0T6;V ~ i 51 _ 44Th ~~ ,Fir SF '~ st SE __ AV SE ~? ''-'3N; CI SF c~x.L tR;r._ i r t• y 1 - - - _ ~ PELF; ~(/ ~`. ~, ,~ - - -- - -----~ I,~\i Y G~1~. ~ `~ a~ \ ~/ ~ f ~ h Q • - - - - kD e' v ~F? N7 Sf ~ 5 •TST `~.aS.r` ~ LO.dGiS12E ~ y~Si, ~~~! cT~r. N` ti4'~ ';i C-` ~ ~ y'`En~~ ~~ ~ T/fs~ i!;SQUHL~Y PQ~ «.~ys '~ ~ ?~ si ca RO •. GOL` COUP.S'< )>:~ P.,O\ JTO S C~F~(f~ uv~,,~'F `("- `L'am .~Q' ~~ T aci',~1~/~ ~~ 1!j`. ~~. _ w ~ Ad's, I O - 6 SF E L't7:.Hlk 1 . ~K i ~ ~~ I I h`C , ~E t L / / s~ FS R N t ~ 1p4TH I ~~s ~ ~041H b,y SF ~ . 1C4T11 A\i ~~ / ~ F `;~,~.. 4`.` ",~c}a ^ ?L Sc ~ ~EVElN TER4h 'r!Y SC L . .! is -- rat ~ ice' ~: ]DSTH AV SE \ ~ vv, 14~ ~ • rrr,:e~z~ r-E ' ~> .. T1;7 I uu ins sT %_, ~ ~~~ ~ SN -_ ~ <a ~fORGE HD SE / ~ ~ o I n ~~° I .K Reference: Pierce County Map 931 By Thomas Brothers Maps Dated 2007 NORTH NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information resulgng from black & white reproductions of this plate. Y ~' 1 1 I~ ~~~ ... _. ~~~• f j o s R 0 ~i ~ `~~ ` #4 Vicinity Map Proposed Mini-SelfStorage & Boat/RV Yelm, Washington Drwn. GLS Date 11/15/2006 Proj. No. 0632 Checked SSR Date Nov. 2006 Plate 1 C 3J0 Aso _. I TP-1 _ I TP-3 ~ ~"~ I RV t Boat Parking -~ -r-TP-0 -' I RV t Boat Parking TP-2 Mini Storage Units Mini Storage Units ~JO i3U 0 0 75 150 300 1" =150' Scale in Feet ~." ~ LEGEND TP-1-~-Approximate Location of I ESNW Test Pit, Proj. No, ES-0632, Oct. 2006 Subject Site ^ Proposed Building Existing Building c~ 0 cm co ~ _ aa~o corn o~c 0 L J~~ d C_ N~ ~ } H ~ 0 a 0 a ~l f NOTE; The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the Drwn. By approximate test locations relative to the approximate locations of GLS e~asting and I or proposed slte features. The information illustrated Checked By is largely based on data provided by the client at the time of our study, ESNW cannot be responsible for subsequent design changes SSR or interpretation of the data by others, Date 1111512006 NOTE; This plate may contain areas of color, ESNW cannot be Proj, No. responsible for any subsequent misinterpretation ofthe information resulting from black & white reproductions of tltis plate. 0632 Plate 2 z f~ C~ U ,s5 ;;o ~~ ~ ~~~ ~.•o 7JG `V cn V~. a~o:a5 ~~o s~, Earth Solutions IOIWLL~ SOIL CLASSIFICATION CHART SYMBOLS TYPICAL MAJOR DIVISIONS GRAPH LETTER DESCRIPTIONS • G~ WELL-GRADED GRAVELS, GRAVEL - MIXTURES LITTLE OR NO GRAVEL GRAVELS ~ ~ , ~ AND ~ ES GRAVELLY SOILS ' ° O° ; ~° POORLY-GRADED GRAVELS, (LITTLE OR NO FINES) o O~o 0 GP GRAVEL -SAND MIXTURES, LITTLE O tJ o O OR NO FINES COARSE a GRAINED ° GRAVELS WITH °~ °° ° 0 G~ stLTYGRAVELS,GRAVEL-SAND- SOILS MORE THAN 50 ~ FINES ° ~ SILT MIXTURES OF COARSE o FRACTION RETAINED ON NO. 4 SIEVE (APPRECIABLE ~.`. CLAYEY GRAVELS, GRAVEL -SANG - AMOUNT OF FINES) CLAY MIXTURES MORE THAN 50oA SAND CLEAN SANDS SW WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES OF MATERWL IS AND LARGER THAN SANDY N0.200 SIEVE SIZE SOILS (LITTLE OR NO FINES) SP POORLY-GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES RE TH ° SANDS WITH SM SILTY SANDS, SAND -SILT MO AN 50 ,6 FINES MIXTURES OF COARSE FRACTION PASSING ON NO. 4 SIEVE (APPRECIABLE S+`. CLAYEY SANDS, SAND -CLAY AMOUNT OF FINES) MIXTURES INORGANIC SILTS ANO VERY FINE ML SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY SILTS INORGANIC CLAYS OF LOW TO FINE AND LIQUID LIMIT `.L MEDIUM PLASTICITY, GRAVELLY GRAINED CLAYS LESS THAN 50 CLAYS, SANDY CLAYS, SILTY SOILS CLAYS, LEAN CLAYS oL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY .MORE THAN 50% OF MATERIAL IS ~ M}~ INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SMALLER THAN SILTY SOILS NO. 200 SIEVE s¢E SILTS AND LIQUID LIMIT `.H INORGANIC CLAYS OF HIGH CLAYS GREATER THAN 50 PLASTICnY ®I'I ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS , HIGHLY ORGANIC SOILS ... •` ~~ ~' ~~ ~"~ PT PEAT, HUMUS, SWAMP SOILS WITH ~~~ ~~~~ ~~~~ ~~, HIGH ORGANIC CONTENTS. DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. Earth Solutions NW, LLC TEST PIT NUMBER TP-1 2881 152nd Avenue N.E. ~ ~ Redmond, WA 98052 PAGE 1 OF 1 Telephone: 4252843300 Fax: 4252842855 CLIENT Randy Weber PROJECT NAME Proposed Mini-SeffStoraae & Boat/RV ~ PROJECT NUMBER 0632 PROJECT LOCATION Yelm. Washington DATE STARTED 10/28/06 COMPLETED 10/28/06 GROUND ELEVATION 332 ft TEST PIT S12E EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION - LOGGED BY RJ CHECKED BY RJ AT END OF EXCAVATION - NOTES Depth of Topsoil 8 Sod 6": grass AFTER EXCAVATION - ~ w ~w ~ _ " a ~ a j TESTS ~ ~ p MATERIAL DESCRIPTION QZ = O ~ ~~ 0 SM '~ '• 5 Brown silty SAND with gravel, loose, moist : 0 MC = 14 60% . 331. 5 . Q° Brown poorly graded GRAVEL with sand, loose, moist ~ .. O ° MC = 1.30 /o o p° -trace mottling ~ Q ° ~° ~ O ° Q° -contains cobbles 5 0 0 GP 0 ° Q° { ~~ MC = 3.10% oO~ ° Q° o ~ MC=3.70% 0 o~° Fines = 1.90°k 0 p ~ [USDA Classfication: extn:mety gravelly sandy LOAM] 0 0 10 0 10.0 322.0 Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 10.0 feet. m ~~ ° 'a c~ f`! JJ f Qm W Z W C9 Earth Solutions Nw, LLC TEST PIT NUMBER TP-2 2881 152nd Avenue N.E. Redmond, WA 98052 PAGE 1 OF 1 Telephone: 4252843300 Fax: 4252842855 CLIENT _Randv Weber PROJECT NAME --Proposed Mini-SetfStoraae & Boat/RV 1 PROJECT NUMBER 0632 PROJECT LOCATION Yelm. Washington DATE STARTED 10/28/06 COMPLETED 10/28/06 GROUND ELEVATION 330 ft TEST PIT Sl2E EXCAVATION CONTRACTOR Client Provided GROUNDWATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION - LOGGED BY RJ CHECKED BY RJ AT END OF EXCAVATION - NOTES Depth of Topsoil 8 Sod 6": grass. AFTER EXCAVATION - w 1 o~ ~~ ~ g TESTS ~ ~ U a 0 J MATERIAL DESCRIPTION ~ Z ~ ~ . 0 ' Brown silty SAND wfth gravel, loose, moist SM : MC = 4 40% ' ' ` 1'0 329.0 . '~ Brown well graded GRAVEL with sand, loose, moist to wet ' MC = 12.50°.b ~ Fines =1.20°~6 • ~' ~~ [USDA Classification: extremely gravelly coarse SAND] GW •'. ' t • 5 .'. • ~ ~ ~ l ` MC = 3 20% g'~ 324.0 ~ ' . . ° Q° Brown poorly graded GRAVEL with sand, loose, moist 0 0 Q [USDA Classfication: extremely gravely loamy coarse SAND] GP o p Q I O O° I O Q 10 . MC = 4.20% a 10.0 320 Fines = 3.00% .0 Test pit temrnated at 10.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 10.0 feet: ~' o Z d ," ) m z C ..s a 'a w z i~ Earth Solutions Nw, LLC TEST PIT NUMBER TP-3 2881 152nd Avenue N.E. ~ Redmond, WA 98052 PAGE 1 OF 1 Telephone: 4252843300 Fax: 4252842855 CLIENT Randv Weber PROJECT NAME Proposed Mini-SeffStoraae & Boat/RV `; PROJECT NUMBER 0632 PROJECT LOCATION _Yelm, Washington DATE STARTED 10/28/06 COMPLETED 10/28!06 GROUND ELEVATION 330 ft TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION - LOGGED BY RJ CHECKED BY RJ AT END OF EXCAVATION - NOTES Depth of Topsoil 8 Sod 6": grass ~ AFTER EXCAVATION - w _ Q ~ ~W ~ g TESTS ~ ~ U ~ p MATERLAL DESCRIPTION Z ~ U N 0 ~ Brown silty SAND with gravel, loose, moist SM : . MC = 10 20% _ ' ` 1'0 329.0 . '• Brown weN graded GRAVEL with sand, loose, moist MC =1.40% ~ ~ •'• MC =1.90% Fines = 0.20% ~~ [USDA Classification: extremely gravelly loamy coarse SAND] °'. ' • 5 MC = 5.00% .'• Fines = 3.80°k GW ~ ~ [USDA Classification: extremely gravelly loamy coarse SAND] ~• ' • •'. ' ! °'. ' ~ •'. 10 10.0 320.0 MC = 3.70% Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 10.0 feet. Earth Solutions NW, LLC TEST PIT NUMBER TP-4 2881 152nd Avenue N.E. PAGE 1 OF 1 Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855. CLIENT Randv Weber PROJECT NAME Proaosed MiniSelFStoraae 8 Boat/RV ': PROJECT NUMBER 0632 PROJECT LOCATION Yelm, Washington DATE STARTED 10/28/06 COMPLETED 10!28/06 GROUNO ELEVATION 331 ft TEST PR SIZE EXCAVATION CONTRACTOR. Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION - ' LOGGED BY RJ CHECKED BY RJ AT END OF EXCAVATION - NOTES Depth of Topsoil 8 Sod 6": crass AFTER EXCAVATION - w } F- W ~ U o ~ ~ g TESTS ~ ~ O ~ MATERIAL DESCRIPTION o_ ~ aZ ' O 0 ~ Brown silty SAND with gravel, loose, moist SM : - .• •= • 1.0 330.0 ' ' o • Brown well graded GRAVEL with sand, loose, moist MC = 2.30% : ~ e'° ' : MC = 1.80% `~ 5 '. GW ~~ ~ 1 ~ ~ ._. ~ ~ MC = 1.70% ~ °'• ' ' ° ®• 10 ~ 10.0 321 0 . Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. Bottom of.test pit at 10.0 feet. ~~ o 1 ~ ~ a' c~ fV pl O I W Z W Earth Solutions Nw, LLC GRAIN SIZE DISTRIBUTION ~ 2881 152nd Avenue N.E. ' ' Redmond, WA 98052 Telephone: (425) 284-3300 Fax: (425) 284-2855 . CLIENT Randy Webber PROJECT NAME Yelm Self Storage PROJECT NUMBER. ES-632 PROJECT LOCATION Yelm U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER C7 m Q: w z F- Z w U W a 6 4 2 1 3/4 1/23!8 3 4 6 810 1416 20 30 40 50 60 100140200 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 100 10 1 0.1 0.01 0.00 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY Specimen Identification ~ • TP-01 ~ 8.Oft. USDA: Brown extr m TP-02 2.5ft. USDA: Brown extrE o • TP-02: 10.Oft. USDA: Brown extrr 3 * TP-03 3.Oft. USDA: Brown e o TP-03. 5.Oft. USDA: Brown extrE Specimen Identification D100 D60 ~ • TP-01 8.Oft. 37.5 16.217 ~ ~ :~ m TP-02 2.5ft. 75 21.227 W Z ~ TP-02. 10.Oft * TP-03 3.Oft. 37.5 37.5 22.437 22.016 O TP-03. S.Oft. 37.5 13.012 Classification LL PL PI Cc Cu ely gravelly sandy loam, USCS: GP 1.31 2.64 Ily gravelly coarse sand, USCS: GW 2.62 11.05 ~I y gravelly loamy coarse sand, GP 3.40 19:72 emely gravelly coarse sand, GP 1.27 3.91 ply gravelly loamy coars e sand, GW 2.48 36.87 D30 D10 %Gravel %Sand %Silt %Clay 11A21 6.15 92.5 5.5 1.9 10.331 1.921 82.5 16.3 1.2 9.316 1.138 81.3 15.7 3.0 12.55 5.625 92.4 7.5 0.2 3.374 0.353 65.7 30.5 3.8 7.0 SPECIAL REPORTS AND STUDIES • Fire Marshal`s Fire Hydrant Locations Approval • Right-of--Way Use Permit 12433.OOl.doc 8.0 OPERATIONS AND MAINTENANCE MANUAL 1 12433.OOl.doc 9.0 BOND QUANTITIES.