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20100129 Stormwater Report 03032011STORMWATEI~ TECI~NICAL INFOI~I~IATIOI'~T REP'OIZT FOIE AMERICA' S CREDIT ~iTNION YELli~T BI~ANCI~ YELIVI, WASI~INGTON Decembe~° 2010 Prepared Por: Arr~erica's Credit ~Tnion P.O. fox 3333 r ort Lewis, ~A 9433 Preps red ~y Jacqueline A. Byron, P.E., Design Engineer Kathleen 1VI. Myron, P.E., Design Engineer Approved ~y: Timothy D. IJoI_derman, P.E., Principal REPOT #1©1h4.10 This analysis is based on data and records either supplied to or obtained by Sound Engineering, Inc. These documents are referenced within the text of the analysis. This analysis has been prepared utilizing procedures and practices within the standard accepted practices of the industry. SOUND ENGINEERING, INC. ~ ' ' ~~ ~ ~~ ~ Y:eoad__o__a®~_®__e__m ~ ~ ~~'~~~ TABLE OF CONTENTS Page 1.0 Project Overview ..................................................................................................... .................. l 1.1 Project Location and Minimum Requirements .................................................... ..................1 1.2 Project Description ................................................................................................ .................3 2.0 Existing Conditions Summary .................................................................................. .................3 3.0 Off-Site Analysis ...................................................................................................... .................4 4.0 Permanent Stormwater Control Plan ........................................................................ ................. 5 4.1 Pre-developed Site Hydrology .............................................................................. .................5 4.2 Developed Site Hydrology ................................................................................... .................5 4.3 Performance Standards and Goals ........................................................................ .................6 4.4 Flow Control System ............................................................................................ .................6 4.5 Water Quality System ........................................................................................... .................7 4.6 Conveyance System Analysis and Design ............................................................ ................. 8 5.0 Discussion of Minimum Requirements .................................................................... ................. 8 6.0 Operation and Maintenance Manual ......................................................................... .................9 7.0 Special Reports and Studies ..................................................................................... .................9 8.0 Bond Quantities Worksheet ....................................................................................... ................9 Appendix A General Exhibits A-1 Vicinity Map A-2 Assessors Map A-3 High Hazard Groundwater Map Appendix B Geotechnical Report Appendix C Basin and Infiltration Trench Calculations C-1 Basin Map C-2 WWHM calculations Appendix D Water Quality Treatment D-1 Water Quality Calculations D-8 Contech Stormwater Solutiai~s Stormfilter details Appendix E Conveyance Calculations Appendix F Maintenance and ®perations Manual Appendix G Stormwater Pollution Prevention Plan (SWPPP) $EI Appendix H November 12, 2010 letter to Tami 1yIerrimar~ SEI 1.0 PROJECT OVERVIEiN 1.1 Project Location and Minimum Requirements This report accompanies the civil engineering plans for the America's Credit Union Yelm Branch project, as submitted to the City of Yeim. The site address is 415 E Yelm Ave, Yelm WA, 98567 Legal Description of Property: That portion of the southeast quarter of the southwest quarter of Section 19, Township 17 north, Range 2 east of the Willamette Meridian, described as follows: Beginning at the most northerly corner of tract conveyed to Oscar C. Swanson and wife by deed recorded under Recording No. 384965, being a point on the southerly line of Yelm Avenue, i 97 feet, more or loss, northwesterly of its intersection with the east line of said subdivision; Thence northwesterly along said scutl-~erly line of Yelm Avenue 120 feet, more or less, to the northeast corner of tract conveyed to Axel Carlson and wife by deed recorded in Volume 199 of Deeds, page 632; Thence southwesterly along the easterly Line of said Carlson tract and along the easterly line of tract conveyed to Axel Carlson and wife by deed recorded in Volume 135 of Deeds, page 17, a distance of 345.3, more or less, to the northwesterly corner of said 5~,~/arson tract; Thence along the boundary of said Swanson tract easterly 142 feet, more or less, and northeasterly 235 feet, more or less, to the point of beginning; Excepting therefrom that portion conveyed to the CitS~ of Yelm by instrument recorded under Recording No. 3418624; In Thurston County, Washington. Parcel No.: 22719342800 Property Zoning: C-1 See the associated topographic boundary survey as submitted with the plan set. Also see the vicinity map provided within Appendix `A'. SI All storm drainage requirements have been designed according to the 2005 Stormwater Management Manual for• Western Washington. Stormwater runoff from the developed site will be collected and conveyed via tightlined systems to infiltration trench beds. Prior to release into the trenches, pollution generating surface runoff is designed to be conveyed through a biofiltration Swale (Sub Basin 1) and a "Contech" Stormwater Solutions Stormfilter catch basin (Sub Basin 2). Minimum requirements as listed in Volume 1 of the 20C5 Stormwater Management Manual for Western Washington are: 1. Preparation of Stormwater Site Plans 2. Construction Stormwater Pollution Prevention (SWPPP) 3. Source Control of Pollution 4. Preservation of Natural Drainage Systems and Outfalls 5. On-site Stormwater Management 6. Runoff Treatment 7. Flow Control 8. Wetlands Protection 9. Basin/Watershed Planning 2 S'- 10. Operation and Maintenance 1.2 Project Description The total site area is 34,045 square feet (0.782 acresl. The proposal is to construct a 4,380 square foot building housing a credit union and coffee house. The development will include stormwater facilities, utilities, roadways, parking areas, and landscaped areas. Approximately 17,026 square feet will consist of asphalt pavement and concrete walkways, with 11,661 square feet of landscaped areas. The proposed parking area will consist of 20 parking stalls, i of which is a handicapped stall. Two Type 1 driveway approaches are proposed for access from Yelm Avenue to the site. The proposed storm drain system onsite has been broken into two sub basins which will collect and convey all pollution generating stormwater nmoff from the paved areas to a biofiltration Swale (Sub Basin 1) and a Stormfilter catch basin by Contech Stormwater Solutions (Sub Basin 2) for water quality treatment, then to the associated infiltration beds. Runoff from non-pollution generating surfaces will be collected and conveyed directly to the infiltration beds. 2.0 EXISTING CONDITIONS SUMMARY The project parcel is bordered to the north by Yelm Ave East (SR 507) and to the east, west, and south by residential properties: The majority of the site is relatively flat (slopes of <1%). The southwest corner of the site slopes 2% to 3%. An existing residence with SEI detached garage is located in the north and central portions of the site. An abandoned shed is located in the south portion of the site. Vegetation in the north and central portions of the site consists of lawn grass, ornamental trees and shrubs, and fruit trees. Conifer trees are along the west boundary of the site and Lombardy Poplars are located in the south portion of the site. Due to this flat topography of the site, the majority of the runoff infiltrates onsite, with a small portion of the runoff sheet flowing to the southwest corner. A Geotechnical study was performed by E3RA, Inc., see Appendix `B'. 3.0 OFF-SITE ANALYSIS Due to the flat topography of the site and the highly permeable soils found onsite, it is likely that much of the existing runoff infiltrates and is conveyed via subsurface flows. Currently, a WSDGT Swale and infiltration trench are located along the frontage of the site. Stormwaier runoff from Yelm Avenue is conveyed to the infiltration trench via two curb breaks. Stormwater entering the northwesterly curb break drains into the westerly portion of the Swale where it then flows to an existing catch basin approximately 5 feet to the west. Stormwater entering the southeasterly curb break flows to the easterly portion of the Swale where it ponds, infiltrates and eventually flo~x~s to the west. As discussed in the November 12, 2010 letter from Sound Engineering, Inc. to Tami Merriman at the City of Yelm, it was determined from a site investigation that the function of the Swale is for conveyance only, with. very little or no treatment occurring (see appendix "G" for letter). To facilitate the installation of the new driveways, the existing curb breaks must be relocated and a new catch basin installed: The relocated curb breaks and the new catch SEI basin will be located such that the s~.~~ale will continue to function as it does currently. The existing catch basin will be preserved; the RIM elevation will be raised to the driveway finished grade elevation and a solid lid will be added. 4.0 PERMANENT STORMIlIr'ATER CONTROL PLAN 4.1 Pre-developed Site Hydrology In the pre-developed condition, the site is mostly flat, sloping slightly (2% to 3%) in the southwest corner. The majority of the runoff likely is infiltrated onsite. 4.2 Developed Site Wydrology The developed site is broken into two sub basins: The first sub basin (Sub Basin 1 j is located in the northwest and southern sections of the site. Stormwater runoff generated by roadway, sidewalk, and parking areas will be collected and conveyed to a biofiltration Swale for water quality treatment. Flow is then conveyed to an infiltration trench system which consists two beds each 71' long x 6' wide. Roof runoff from the building will be conveyed directly to the infiltration system, bypassing the biofiltration swale since it does not require treatment. The second sub basin (Sub Basin 2) is located in the northeast section of the site. Stormwater runoff generated by roadway, sidewalk, and parking areas will be collected and conveyed to a Contech Sto~mwcrter Solutions Stormfilter catch basin housing one cartridge for water quality treatment. Flow is then conveyed to an infiltration trench bed #2 which is 14' long x ~' wide. Roof runoff from the drive-thru canopy will also be conveyed to bed #2, as well runoff from the landscaped area. Both the roof and landscape SEI runoff will bypass the Stormfilter catch basin since it does not require treatment. See Appendix 'C' for basin exhibits and trench calculations; see Appendix 'D' for water quality calculations and Stormfilter details. 4.3 Performance Standards and Coals Infiltration trench bed facilities will be implemented in accordance with minimum requirement #5 On-site Stormwater Management Vol. 1 sec. 2.5.5 of the 2005 D.O.E. Stormwater Management Manual for Western Washington. The biofiltration Swale and Contech Stormwater Solutions Stormfilter will be implemented in accordance with minimum requirement #6, Runoff Treatment Vol. 1 sec 2.5,6 of the above referenced manual. This satisfies the required "Basic treatment" facilities per Vol. 1 sec. 4.2. 4.4 Flow Control System Storm runoff generated by proposed impervious surfaces onsite is designed to be infiltrated within the previously discussed infiltration trench beds. Doing so satisfies on- site stormwater management requirements for flow control. Three test pits were dug in the north, central, and south portions of the site to accurately analyze the groundwater elevations throughout the site. No evidence of groundwater was observed in any of the test pits, alI of which extended down to a depth of 9 feet. Note that the site is located outside of the Thurston County High Hazard Groundwater area (see Appendix `A'). Based on these cbservations, the minimum 5' separation required between the bottom of the infiltration trenches and the seasonal high water mark will be SEI maintained. See Appendix `B' for Geotechnical analysis of test pit findings, and refer to the grading and drainage plans for trench elevations. The infiltration beds were sized using the Western Washington Hydrology Model Version 3 (WWHM3), see Appendix `C'. The geotechnical analysis indicated that rapidly permeable gravelly sand underlies the site. Based on this analysis, along-term infiltration rate of 10 in/hr was used to size the trenches. This rate was obtained by assuming the maximum long-term rate (10 in/hr) listed in Table 3.7 Vol. III p. 3-76 of the 2005 D.O.E Stormwater Management Manual,for Western Washington. Due to high permeability of the exisiing soils, ±he infiltration trenches are designed for flow control only; see the water quality system section for treatment facility design. 4.5 Vlfater Quality system A biofiltration Swale (Sub Basin 1) and a Contech Stormwater Solutions Stormfilter catch basin (Sub Basin 2) were chosen to treat the Stormwater runoff from the traveled area (travelways, parking stalls, sidewalks) of the developed site. Runoff collected from roofs will bypass the water quality system and be routed directly to the infiltration trench beds. Each of the infiltration trenches is preceded by either the biofiltration Swale or the Stormfilter catch basin for the pollution generating surface runoff. The cartridge count for the Stormfilter cartridge was calculated using WWHM3 to generate the target water quality 15 minute flow rate, then by applying the following equation: (Treatment flow)(449gpm/cfs / 7.5 gpm/cart.) _ # cartridges 7 ~_ ~ ~I See Appendices'C' and `D'. 4.6 Conveyance System Analysis and Design Conveyance calculations have been performed and can be found in Appendix `E'. 5.0 DISCUSSION OF MINIMUM REQUIREMENTS The Minimum Requirements have been addressed as discussed below. 1. Preparation of Stormwater Site Plans: Included herein. 2. Construction Stormwater Pollution Prevention Plan (SVJPPP): Included herein (See Appendix 'G ). 3. Source Control of Pollution: As prescribed in the ?005 Stormwater Management Manual for Western Washington, and included herein. (See Appendix 'F). 4. Preservation of Natural Drainage Systems and Outfalls: Tlie project does not abut a natural drainage system or outfall, flow control is designed as infiltration. 5. On-Site Stormwater Management: Onsite infiltration trenches have been sized in accordance with the 2005 Stormwater Management Manual for Western Washington. 6. Runoff Treatment: A biafiltration swale and a SPormfilter catch basin will be provided. 7. Flow Control: runoff is designed to infiltrate onsite. S. Wetlands Protection: N,iA 9. Basin/Watershed Planning: NlA 10. Operation and Maintenance: Included herein. (See Section 6.0) SEI 6.0 OPERATION AND MAINTENANCE MANUAL An operation and maintenance manual is included with this report, see Appendix `F', and can serve as a stand-alone guide to the property owner upon completion of the project. 7.0 SPECIAL REPORTS AND STUDIES Not applicable. 8.0 BOND QUANTITIES VIIORKSHEET To be submitted at final plan approval. SOUND ENGINEERING, INC. Jacgzteline A. Byron, P.E., Design Engineer Kathleen M. Byron, P.E., Design Engineer Timothy D. Holclerman, P.E. Pr°incipal SEI APPEl~T~IX A General Exhibits SCI Project: America's Credit Union Yelm Branch Location: 415 E Yelm Ave, Yelm ILIA ~/icini#y i>iiap ~~ ~~{~ ~~~ ~~ ~. ~ r .~ ~`~~ ~~ ~- ~~ Y LM c'~ CITY ~~ R y~ 5 ~~ ~~~ ~~ ~s~-1-E t7 HRAN -MEMOftLAL" PAR v~ 1G4TH AVE SE / ~ 104TH AVE SF - ~ J YELM TERRA, WA SE 105TH WAY SE "~ Project: America's Credit Union Yelm Branch Location: 415 E Yelm Ave, Yelm WA Accessor's Map ~~r ~~~ 64420901300 64420900700 s ~ ,~ 64420900800 -r ~ 7 l ''~4 64420901100 ~ •ti. "~+ h k .q ~, 0 - 64420900900 ~... _ ~ ~ - 41200 ~y ~' ~ `. 22719340300 + ,~ - - p. ~^°v5 jG '' f, ~ 3 s ~4 { _'~ 22719341901 _ ~ r`~. • ~ • 22119341300 ,• l , *' , 22719343100 , ' •~' -, ~~'rf 22719341900 '9y~ 22719342500 `rE 22719342200 ;' '' , ~'~j 22719342401 - 64420800100 22719342202 64420800500 22719342400 22719342201 - 64420800600 22719342600 64420800700 22719342402 64420700400 22719342800 y~ _ '~~ 22719342700 ti 64420700600 `~_. g 22719343003 64420700700 64420701000 f' 22719343000 22719342900 i` 22719343002 64420700900 22719343001 Site Location 22719340500 22719340600 22719342901 2: '~- Project: Location: F~ Fti 4 6~ America's Credit Union Yelm Branch 415 E Yelm Ave, Yelm WA High Hazard Groundwater Map tiFS~`~ s 4~F ~ ~.~:._ i Qy r Z`~~ V4 kr ~4c~~ S~ d' RG~ sr a`` ~F~~ F~ S~ `~ q 4~5~~ ~ ,.---.. o~'°ap~ y~` ~'~ I S S tP SE .. 9~ ~'., M~, ~" a`` ~ Q4 ~~~ ~i`~ Q~ *~~ °j 4i4`~SE T / 9,Q ~< ys I~ F (I _NE 7 '~, __ _ . w '. ~ '~ ~9i oqC 94F Sf a Site Location High Groundwater Hazard Area Ref. Thurston County GeoData Center AyE SE_~ _! a N a a ".~~` ~~~~l~l ~~1~ Geotechnical Report SEI GEOTECHNICAL REPORT AMERICA'S CREDIT UNION YELM BRANCH 415 EAST YELM AVENUE YELM, WASHINGTON Submitted to: America's Credit Union PO Box 33338 Ft. Lewis, Washington 98499 Submitted by: E3RA, Inc. 201-160th street South Suite 401 Tacoma, Washington 98448 November 9, 2007 T07278 ~~ ~ SABLE OF CONTENTS Page No. 1.0 SITE AND PROJECT DESCRIPTION ............. ......................................................................1 2.0 EXPLORATORY METHODS ........................... ......................................................................1 2.1 Test Pit Procedures .............................. ......................................................................2 3.0 SITE CONDITIONS ......................................... ......................:...............................................3 3.1 Surface Conditions ............................... ......................................................................3 3.2 Soil Conditions ..................................... ...................................................................... 3 3.3 Groundv~ater Conditions ...................... ......................................................................3 3.4 Seismic Conditions .............................. ......................................................................3 3.5 Liquefaction Potential ........................... .........:............................................................3 3.6 Infiltration Conditions .:.......................... ......................................................................4 4.0 CONCLUSIONS AND RECOMMENDATIONS ......................................................................4 4.1 Site Preparation ................................... ......................................................................4 4.2 Spread Footings ................................... ......................................................................6 4.3 Slab-on-Grade Floors ........................... ......................................................................7 4.4 Drainage Systems ................................ ......................................................................7 4.5 Asphalt Pavement ............................... ...................................................................... $ 4.6 Structural Fill ......................................... ......................................................................9 5.0 RECOMMENDED ADDITIONAL SERVICES ... ...................................................................10 6.0 CLOSURE ......................................................... ...................................................................11 List of Tables Table 1. Approximate Locations and Depths of Explorations ....................................................................... 2 List of Figures Figure 1. Topographic and Location Map Figure 2. Site and Exploration Plan APPENDICIES APPENDIX A Soils Classification Chart and Key to Test Data .........................................................................................A-1 Logs of Test Pits TP-1 through TP-3 ................................................................................................ A-2...A-4 PO Box 44890 Tacoma, WA 98448 253-537-9400 253-537-9401 Fax ~3 November 9, 2007 T07278 America's Credit Union P.0. Box 33338 Fort Lewis, Washington 98499 Attention: Ken Leonard Subject: Geatechnical Repart America's Credit Union Yelm Brancl`i 415 East Yelm Avenue Yelm, Washington Dear Mr. Leonard: E3RA is pleased to submit this report presenting our geotechnical evaluation for the proposed America's Credit Union Branch to be located at 415 East Yelm Avenue in Yelm, Washington. The purpose of our evaluation is to provide geotechnical recommendations and conclusions concerning the construction of a one story bank building and to provide general recommendations regarding onsite infiltration of stormwater. This report has been prepared for the exclusive use of America's Credit Union, and their consultants, for specific application to this project in accordance with generally accepted geotechnical engineering practice. 1.0 SITE AND PROJECT DESCRIPTION The proj ect site is located on the south side of East Yelm Avenue in downtown Yelm, Washington, as shown on the enclosed Location Map (Figure 1). The site is in an area of mixed commercial and residential use that is gradually evolving into exclusively commercial usage. The site fronts East Yelm Avenue for a distance of 112 feet and extends south from the roadway about 250 feet. We understand that the new Credit Union Building will be one-story supported on grade with aslab-on-grade floor. The area surrounding the new building will be used for paved parking, drive up banking, and site access. 2.0 EXPLORATORY METHODS We explored surface and subsurface conditions at the proj ect site on October 10, 2007. Our exploration program comprised the following elements: A surface reconnaissance of the areas to be developed; Three test pits (designated TP-1 through TP-3) advanced across the site; and ll~ November 9, 2007 T07278/America's Credit Union Geotechnical Report A review of published geologic and seismologic maps and literature. E3RA, Inc. Table 1 summarizes the approximate functional locations and termination depths of our subsurface explorations, and Figure 2 depicts their approximate relative locations. The following sections describe the procedures used for excavation of test pits. TABLE 'i APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Termination Depth Exploration Functional Location (feet) TP-1 North site 9 TP-2 Central Site 9 TP-3 South site 9 Elevation datum: Unavailable The specific number and locations of our explorations were selected in relation to the existing site features, under the constraints of surface access, zmderground utili~y conflicts, and budget considerations. It should be realized that the explorations performed and utilized for this evaluation reveal subsurface conditions only at discrete locations across the prof ect site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recom<Ynendations contained in this report to reflect the actual site conditions. 2.1 Test Pit Proeedw•es Our exploratory test pits were excavated with atrack-mounted excavator by an operator from Rockcrest Construction under contract to E3RA. An engineering geologist from our firm observed the test pit excavations and logged the subsurface conditions. The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in each test pit, based on our field classifications. Where a soil contact was observed to be gradational or undulating, our logs indicate the average contact depth. We estimated the relative density and consistency of the in-situ soils by means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the approximate depths of any sidewall caving or groundwater seepage observed in the test pits. The soils were classified visually in general accordance with the system described in Figure A-l, which includes a key to the exploration logs. Summary logs of the explorations are included as Figures A-2 through A-4. ~~ November 9, 2007 T07278/ America's Credit Union Geotechnical Report 3.0 SITE CONDITIONS E3RA, Inc. The following sections present our obser=aations, measurements, findings, and interpretations regarding, surface, soil, groundwater, seismic, liquefaction, and infiltration conditions. 3.1 Surface Conditions The project site and nearby areas are relatively level. Asingle-family residence with detached garage currently occupies the north and central portions of the site. An abandoned shed occupies the south portion of the site. Vegetation on the central and north portions of the site consists of lawn grass, ornamental trees and shrubs, and fruit trees. Several Lombardy Poplars grow on the south part of the site. A line of conifers grow along the west boundary. No other signs of surface flow were noted ir. the vicinity of either the pond or planned buildings. No seeps or springs were observed. 3.2 Soil Conditions Soils conditions on the site are relatively uniform, Generally, we observed about 1 foot of sod and topsoil overlying, to a depth approximately 4 feet, loose, dark brown, silty fine sand, which, in the upper foot or so, contained abundant roots. In all of our test pits, we observed loose to medium dense recessional glacial outwash consisting of gravelly sand with scattered cobbles and few fines underlying the silty fine sand layer, which extended to a depth of 9 feet. .The enclosed exploration logs (Appendix A) provide a detailed description of the soil strata encountered in our subsurface explorations. 3.3 Groundwater Conditions At the time of our reconnaissance and subsurface explorations (October 9, 2007), we did not observe groundwater in any of our test pits, all of which extended to a depth of 9 feet. We did not observe indications of seasonal high groundwater, such as soil mottling, in any of our explorations. We do not expect that groundwater will be encountered during site excavation. 3.4 Seismic Conditions Based on our analysis of subsurface exploration logs and our review of published geologic maps, we interpret the onsite soil conditions to correspond with a seismic site class D, as defined by Table 1613.5.5 of the 2006 International Building Code (IBC). 3.5 Liquefaction Potential Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by shear strains, as could result from an earthquake. Research has shown that saturated, loose, fine to medium sands with a fines (silt and clay) content less than about 20 percent are most susceptible to liquefaction. Our onsite subsurface explorations did not reveal saturated (or potentially saturated), loose, silty sand layers or lenses. ~~ November 9, 2007 E3RA, Inc. T07278/America's Credit Union Geotechnical Report 3_6 Infiltration Conditions The silty sand layer, ~~~hich underlies a surficial mantling of topsoil and extends down to depths of 3 to 4 feet, is comprised of loose, silty fine sand and is slowly to moderately permeable. The underlying glacial outwash layer, observed at depths below 3 to 4 feet, is comprised of loose to medium dense gravelly sand witl-i few fires and is rapidly permeable. 4.0 CONCLUSIONS AND RECOIVIlVIIINDATIONS Plans call for the construction of a r~ew Credit Union Building, pa ved parking and roadways, and possibly onsite stormwater infiltration. We provide these general conclusions and recommendations: Feasibility: Based on our field explorations, research, and analyses, the proposed structure and pavement appears feasible from a geotechnical standpoint, provided the recommendations presented in Section 4 are followed. Foundation O tp ions: VJe recommend conventional spread footings that bear on the sandy glacial outwash layer that was observed at depths below 3 to 4 feet. Because this layer is somewhat loose, we recommend that subgrade soils be vigorously compacted prior to the placement of forms and rebar. Spread footing recommendations are provided in Section 4. Floor Options: We recommend slab-on-grade floors for the new credit union building. Floor subgrade soils that will be exposed after the stripping of organic surficial soils are somewhat loose. For this reason, we recommend that floor subgrades be vigorously surface compacted, using vibratory drum roller or other heatry-duty compaction device, before floors are constructed. Recommendations for slab- on-grade floors are provided in Section 4. infiltration Conditions: Rapidly permeable gr'aweily sand underlies the site, and, based on our observations of subsurface conditions, seasonally high groundwater does not rise to within 9 feet of existing grades. For these reasons, the site is amenable to onsite infiltration of stormwater The following sections present our specific geotechnica"t conclusions and recommendations concerning site preparation, spread footings, slab-on-grade floors, drainage, asphalt pavement, and structural fill. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard Plans cited herein refer to WSDOT publications M41-10, Standard Spec fcations for Road, Bridge, and Municipal C031st1"L1CtI:Jn, and M21-O1, Standard Plans for Road, Bridge, and Municipal Construction, respectively. 4.1 Site Preparation Preparation of the project site should involve erosion control, temporary drainage, clearing, stripping, cutting, filling, excavations, and subgrade compaction. Erosion Control: Before new construction begins, an appropriate erosion control system should be installed. This system should collect and filter all surface water runoff through either silt fencing or a series of properly placed and secured straw bales. We anticipate a system of berms and drainage ditches around construction areas will provide an adequate collection system. If silt fencing is selected as a filter, this fencing fabric should meet the requirements of WSDOT Standard Specification 9-33.2 Table 3. In addition, silt fencing should embed a 4 ~~ November 9, 2007 E3RA, Inc. T07278/ America's Credit Union Geotechnicai Report should embed a minimum of 6 inches belovY~ existing grade. If straw baling is used as a filter, bales should be secured to the ground so that they wilt not shift under the weight of retained water. Regardless of the silt filter selected, an erosion control system requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has shifted above ground stLrface should be replaced or repaired as soon as they are identified. Temporary Drainage: We recommend intercepting and diverting any potential sources of surface ornear-surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Based on our current understanding of the construction plans, surface and subsurface conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff: Clearing and Strippi~: After surface and near-surface water sources have been controlled, the construction areas should be cleared and stripped of all topsoil. Our explorations indicate that about 1 foot of topsoil overlies the site, but abundant roots extend down to 2 feet below the sr~rface in isolated areas. Where encountered, root rich soils will also have to be removed. Site Excavations and Utility Trenches: Based on our explorations, we expect that excavations will encounter medium dense sandy soils. Site soils can be excavated using standard excavation equipment. Dewaterin~: Our site explorations did not encounter groundwater, nor do we expect that significant quantities of groundwater will be encountered during site excavation. However, if groundwater is encountered, we anticipate that an internal system of ditches, sumpholes, and pumps will be adequate to temporarily dewater excavations. Temnorarv Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper than 1'/zH:1V (horizontal to vertical) and should conform to ti~'ashingtor~ Industrial Safety and Health Act (WISHA) regulations. Sub~rade Compaction: Exposed subgrades for footings and floors should be compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed within a subgrade should be overexcavated and replaced with a suitable structural fill material. Site Filling: Our conclusions regardil-~g the reuse of onsite soils and our comments regarding wet-weather filling are presented subsequently. Regardless of soil type; all fill shoui_d be placed and compacted according to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent per the American Society for Testing and Materials (ASTM) D-1557. 5 November 9, 2007 E3RA, Inc. T07278/ America's Credit Union Geotechnicai Report should embed a minimum of 6 inches below existing grade. If straw baling is used as a filter, bales should be secured to the ground so that they will not shift under the weight of retained water. Regardless of the silt filter selected, an erosion control system requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has shifted above ground stLrface should be r eplaced or repaired as soon as they are identified. Temporary Drainage: We recommend intercepting and diverting any potential sources ofsurface ornear-surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Based on our current understanding of the construction plans, surface and subsurface conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff. Clearing and Stripping: A fter surface and near-surface water sources have been controlled, the construction areas should be cleared and stripped of all topsoil. Our explorations indicate that about 1 foot of topsoil overlies the site, but abundant roots extend down to 2 feet below the s?u-face in isolated areas. Where encountered, root rich soils will also have to be removed. Site Excavations and Utility Trenches: Based on our explorations, we expect thai excavations will encounter medium dense sandy soils. Site soils can be excavated using standard excavation equipment. Dewaterin~: Our site explorations did not encounter groundwater, nor do we expect that significant quantities of groundwater will be encountered during site excavation. however, if groundwater is encountered, we anticipate that an internal system of ditches, sumpholes, and pumps will be adequate to temporarily dewater excavations. Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper than 1 %2H:1 V (horizontal to vertical) and should conform to Washington Industrial Safety and Health Act (WISHA) regulations. Subgrade Compaction: Exposed subgrades for footings and floors should be compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed within a subgrade should be overexcavated and replaced with a suitable structural fill material. Site Fiilin~: Our conclusions regardinng the reuse of onsite soils and our comments regarding wet-weather filling are presented subsequently. Regardless of soil type; all fill sho~2ld be placed and compacted according to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent per the American Society for Testing and Materials (ASTM) D-1557. 5 November 9, 2007 E3RA, Inc. T07278/America's Credit Union Geotechnical Report Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural fill: Surficial Organic Soils: Topsoil, duff, sad, or other organic soils are not suitable for use as structural fill under any circumstances, due to high organic content. Consequently, these materials can be used only for non-structural purposes, such as in landscaping areas. Upper Sil Fine Sand: The upper silty fine sand layer, which underlies the topsoil layer and extends down to depths of 3 to 4 feet, is sensitive to moisture content variation and will be difficult to reuse during wet weather conditions. Native Glacial Outwash Gravelly Sand: i`'his soil, encountered below depths of 3 to 4 feet, is relatively insensitive to moisture content variations and will provide a good source of structural fill. Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H:1 V. For all soil types, the use of flatter slopes (such as 21/2H:1 V) would further reduce long-term erosion and facilitate revegetation. Slope Protection: We recommend that a permanent berm, Swale, or curb be constructed along the top edge of all permanent slopes to intercept surface flow. Also, a Hardy vegetative groundcover should be established as soon as feasible, to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could be armored with quarry spans or a geosynthetic erosion mat. 4_2 Spread Footings In our opinion, conventional spread footings will provide adequate support for the proposed buildings if the subgrades are properly prepared. We offer the following comments and recommendations for purpose of footing design and construction. Footing Depths and Widths: For frost and erosion protection, the base of all exterior footings should bear at least 18 inches below adj acent outside grades, whereas the base of interior footings need bear only 12 inches below the surrounding slab surface level. To reduce post-construction settlements, continuous (wall) and isolated (column) footings should be at least 18 and 24 inches wide, respectively. Bearing_Subgrades: Footings should bear on in-situ native soils that have been surface compacted or on properly compacted (compacted to a uniform derrsily of at least 95 percent (ASTM D-1557) structural fill Subgrade Observation: All footing subgrades should consist of firm, unyielding, native soils or structural fill materials. Footings should never be cast atop loose; soft, or frozen soil, slough, debris, existing uncontrolled fill, or surfaces covered by standing water. We recommend that an E3RA representative observe the condition of all subgrades before any concrete is placed. 6 November 9, 2007 E3RA, Inc. T07278/ America's Credit Union Geotechnical Report Bearing Pressures: In our opinion, for static loading, footings that bear on properly prepared subgrades can be designed for a maximum allowable soil bearing pressure of 3,000 pounds per square foot (psf). A one-third increase in allowable soil bearing capacity may be used for short-term loads created by seismic or wind related activities. Footin~Settlements: Assuming that footings are based on properly prepared subgrades, we estimate that total post-construction will not exceed 1 inch. Differential settlements for comparably loaded elements may approach one-half of the actual total settlement over horizontal distances of approximately 50 feet. Footing Backfill: fio provide erosion protection and lateral load resistance, we recommend that all footing excavations be backfilled on both sides of the footings and stemwalls after the concrete has cured. Either imported structural fill or nonaorganic onsite soils can be used for this purpose, contingent on suitable moisture content at the time of placement. Regardless of soil type, all footing backfll soil should be compacted to a density of at least 90 percent (ASTM D-1557). Lateral Resistance: Footings that have been properly backfilled as recommended above will resist lateral movements by means of passive earth pressure and base friction. We reconunend using an allowable passive earth pressure of 250 pcf (equivalent fluid weight} and an allowable base friction coefficient of 0.35. 4.3 Slab-On-Grade Floors In our opinion, soil-supported slab-on-grade floors can be used in the proposed structures if the subgrades are properly prepared. We offer the following com~rnents and recommendations concerning slab-on-grade floors. Subgrade Conditions and Observation: All soii-supported slab-on-grade floors should bear on firm, unyielding soils or on suitable, properly compacted structural fill soils. VIWe recommend that the condition of all subgrades and overlying layers be observed by an E3RA representative before atiy fill or concrete is placed. Floor Subbase: After removal of topsoil and root-rich soils which currently cover the site, we recommend that floor subgrade soils be vigorously surface-compacted prior to floor construction, Capillary Break: To retard the upward wicking of groundwater beneath the floor slab, we recommend that a capillary break be placed over the subgade or subbase. Ideally, this capillary break would consist of a 4-inch- thicklayer ofpea gravel or other clean, uniform, well-rounded gravel, such as "Crravel Backfill for Drains" per WSDOT Standard Specification 9-03.12(4). Alternatively, angular gravel or crushed rock can be used if it is sufficiently clean and uniform to prevent capillary wicking. Vapor Barrier: We recommend that a layer of durable plastic sheeting (such as Crosstuff, Moistop, or Visqueen) be placed directly between the capillary break and the floor slab to prevent ground moisture vapors from migrating upward through the slab. During subsequent casting of the concrete slab, the contractor should exercise care to avoid puncturing this vapor barrier. Vertical Deflections: Due to elastic compression of subgrades, soii-supported slab-on-grade floors can deflect downwards when vertical loads are applied. In our opinion, a subgrade reaction modulus of 250 pounds per cubic inch can be used to estimate such deflections. November 9, 2007 T07278/America's Credit Union Geotechnicai Report E3RA, Inc. 4.4 Drainage Systems We offer the following recommendations and comments for drainage design for construction purposes. Perimeter Drains: We recommend that the planned buildings be encircled with a perimeter drain system to collect seepage water. This drain should consist of a 4-inch-diameter perforated pipe within an envelope of pea gravel or washed rock, extending at least 6 inches on all sides of the pipe, and the gravel envelope should be wrapped with filter fabric to reduce the migration of fines from the surrounding soils. Ideally, the drain invert would be installed no more than 8 inches above the base of the perimeter footings. Subfloor Drains: Based on site soil and groundwater conditions, we do not recommend the use of subfloor drains. Discharge Considerations: If possible, all perimeter drains should discharge to a municipal storm drain, sewer system, or other suitable location by gravity flow. Check valves should be installed along any drainpipes that discharge to a sewer system, to prevent sewage backflow into the drain system. Runoff Water: Roof-runoff and surface water runoff should not discharge into the pez~imeter drain system. Instead, these sources should discharge into separate tightline pipes and be routed away from the building to a storm drain or other appropriate location. Gradintr and Capping: Filnal site grades should slope downward away from the building so that runoff water will flow by gravity to suitable collection points, rather than ponding near the building. Ideally; the area surrounding the building would be capped with concrete, asphalt, or low-permeability (silty) soils to minimize or preclude surface-water infiltration. 4_5 Asphalt Pavement Since asphalt pavements will be used for the driveways and parking areas we offer the following comments and recommendations for pavement design and construction. Sub~rade Preparation: After removal of the topsoil and root-rich soils, all soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be overexcavated to a depth of 12 inches and replaced with a suitable structural fill material. All structural fill should be compacted according to our recommendations given in the Structural Fill section. Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 9~ percent (ASTM D-1557), and all soils below 2 feet should be compacted to at least 90 percent. Pavement Materials: For the base course, we recommend using imported crushed rock that is, for drainage purposes, free of fines. For the subbase course, we recommend using imported, clean, well-graded sand and gravel, such as recommended in Section 4.6. Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete pavement over a crushed rock base course. Using the estimated design values stated above, we recommend using the following conventional pavement sections: November 9, 2007 T07278/America's Credit Union Geotechnical Report E3RA, Inc. fNinimum Thickness Pavement Course Parking Areas Asphalt Concrete Pavement 2 inches Crushed Rock Base 4 inches Granular Fill Subbase (if needed) 12 inches High Traffic and Driveway Area: 3 inches 6 inches 18 inches Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an E3RA representative be retained to observe the compaction of each course before any overlying layer is placed. For the subbase and pavement course, compaction is best observed by means of frequent density testing. For the base course, methodology observations and hand-probing are more appropriate than density testing. Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described pavement sections present our minimum recommendations for an average level of performance during a 20-year design life; therefore, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about 10 years. Thicker asphalt and/or thicker base and subbase courses would offer better long-term performance, but would cost more initially; thinner courses would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. 4.6 Structural Fill The term "structural fill" refers to any placed under foundations, retaining walls, slab-on-grade floors, sidewallcs, pavements, and other structures. Our comments, conclusions, and recommendations concerning structural fill are presented in the following paragraphs. Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock, well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit-run"), and miscellaneous mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing the parent materials, are also potentially useful as structural fill in certain applications. Soils used for structural fill should not contain any organic matter or debris or any individual particles greater than a'oout 6 inches in diameter. Fill Placement: Clean sand, granulithic gravel, crushed rock, soil mixtures, and recycled materials should be placed in horizontal lifts not exceeding 8 inches in loose thickness and each lift should be thoroughly compacted with a mechanical compactor. Compaction Criteria: Using the IVlodified Proctor test (ASTM D-1557) as a standard, we recommend that structural fill used for various onsite applications be compacted to the following minimum densities: November 9, 2007 E3RA, Inc. T07278/ America's Credit Union Geotechnical Report Fili Application Minimum Compaction Footing subgrade and bearing pad 95 percent Foundation and subgrade wall backfill 90 percent Slab-on-grade floor subgrade and subbase 95 percent Pavement base and subbase 95 percent Pavement subgrade (upper 2 feet) 95 percent Pavement subgrade (below 2 feet) 90 percent Subar'ade Observation and Compaction Testing: Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this report. The condition of all subgrades should be observed by geotechnical personnel before filling or construction begins. Also, fill soil compaction should be verified by means of in-place density tests performed during fill placement so that adequacy of soil compaction efforts maybe evaluated as earthwork progresses. Soil Moisture Considerations: The suitability of soils used for structural fill depends primarily on their grain-size distribution and moisture content when they are placed. As the "fines" content (that soil fraction passing the U.S. No. 200 Sieve) increases, soils become more sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm, unyielding condition when the moisture content is more than 2 percentage points above or below optimum. For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve. 5.0 RECOMIVIENDED ADDITIONAL SERVICES Because the future performance and integrity of the structural elements will depend largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced geotechnical personnel should be considered an integral part of the construction process. Consequently, we recommend that E3RA be retained to provide the following post-report services: • Review all construction plans and specifications to verify that our design criteria presented in this report have been properly integrated into the design; • Prepare a letter summarizing all review comments (if required by the City of Yelm); • Check all completed subgrades for footings and slab-on-grade floors before concrete is poured, in order to verify their bearing capacity; and • Prepare apost-construction letter summarizing all field observations, inspections, and test results (if required by the City of Yehn). 10 ~~ PJcvemb2r 9, 2007 ~34A, !r,c T072?8/ America's Cradit Unior Geoff°chr~icai gopori b.0 CLOSURE T'he conclusions and recommendations presented in this report are based, in part, on the explorations that we observed for this study; therefore, if variations in the subgrade conditions are observed at a later time, we may need to modify this report to reflect those changes. Also, because the future peI•£ormance and integrity ofthe project elements depend largely on proper initial site preparation, drainage, and constraction procedures, monitoring and testing by experienced geoteclmical personnel should be considered an iniegral part of the construction process. E3RA is available to provide geotechnical morutoruig of soils throughout construction. We appreciate the opportunity to be of service ou this project. If you have any questions regarding this report or airy aspects of the project, please feel free to contact our office. S hicerely, James E Brigham, P.E. Principal Engineer FER:JEB:jm TACO\\Tacoma-serverljob files\2007 JOB FILES\T07278 AMERICAS CREDIT IJI`IION YELM1T07278 America`s Credit Yelm Report.doc Four copies submitted 11 ~~ Fred E. Rennebaum, L.E.G. Senior Geologist TYPO! map pr7nted nn 10/09/07 from "Untitled,tpo" 122°37,000' UPI 122°36,000' UV t~Ga84122°35,000' Ulu ti f ~ O ~_ ~~ ., .~~ s ~ I ~~- ~ ,, f ,fir • ', / _ ~ : ~ ` ,- ~ - .! 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AMERICA'S CREDIT UNION -YELM BRANCH FIGURE 1 P.O Bax 44890 TOPOGRAPHIC AND LOCATION MAP T07278 Tacoma, WA 98448 YELM, WASHINGTON ~l~(- o `° ~ o ~, ti ~~ O ~- I- f N ~ o ~ W W J ~ W ~ o m Q U, ~ W ~ LW U c n. ~ ~ N ~ W Z I H U m ~ m ~ W J E m ~ ~ Q 7- U7 U U -~ ti o ~ ~ W } o .J m ~ W m o ~ ~ ~ Z Z ~ W ~ ~ U LLI O W (n ~ W E- ~ ~ ~ ~ ^ ^ U d' ~1' Ci C!3 a~0 ~ ~ ~ ~ O r ~ ~ ~ ~ ~ ~ O ~ ~ L O r~ (DO RS1~l~M M M ~ ~ ~ ~- M i ~ O ~ ~ `~- gJ ~ O ~ (U6 ~ tMf? .oQG~ ~ e ~ ~ N (n l-- N N ~ ~~ a ~ ' ~ ' F- W ti ~ l , ~ N W ~ ~ O S W l~ M I ~ ~ N ~ ~ Q [Y . ,~' H ~ ~~ .§g~ ,~ ~ ~ F- o w Q ~ S H r~ o G O (/l ~ W zQ°~ o> z gw3cr V) ~ OS Q Qa Z C") p a O V) W W Ca Z >- ~ i W F4 Q ~ ~ } } Q ~C W _ ~ 5 > W M ~ ~ Q W ~ ~ ~ O ~ ~ L7~ ~q O d Ca W -~ O W Z W i-- Ca F - ~ Q ~ ~ G ~ Q Q p_i J W ~ ~-~~ d! L7 W H Q q~, WE- w?d?-cn F-~~~ aoQ~a z~s~=,c~ ~_ APPEIV®I~C A S®ILS CLASSIFICATI®N CHART ANC IdCEY T® TEST DATA ANA L®~S ~F TEST PITS MAJOR DIVISIONS TYPICAL NAMES CLEAN GRAVELS GW ~'~~` WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES GRAVELS '` '~ WITH LITTLE OR ~ NO FINES Gp .b;~°~ POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES MORE THAN HALF p. p: COARSE FRACTION V'M o o SILTY GRAVELS, POORLY GRADED GRAVEL-SANDSILT O o IS LARGER THAN N0 4 SIEV GRAVELS WITH MIXTURES o N z ~ . E OVER 15% FINES GC CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY MIXTURES Q ~ _ °.°° w ~ CLEAN SANDS SW °e°<°>° WELL GRADED SANDS, GRAVELLY SANDS ~ SAND ~ `o O S WITH LITTLE OR NO FINES Sp •: ~' •:' POORLY GRADED SANDS, GRAVELLY SANDS ~ MORE THAN HALF COARSE FRACTION IS SMALLER THAN SM •" ." SILTY SANDS, POOORLY GRADED SAND-SILT MIXTURES SANDS WITH N0.4 SIEVE OVER 15% FINES SC '' CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, ML SILTY OR CLAYEY FINE SANDS, OR CLAYEY SILTS WITH SLIGHT PLASTICITY m SILTS AND CLAYS INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GL GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, '~ o LIQUID LIMIT LESS THAN 50 LEAN CLAYS O o _ _ o ~ OL - ORGANIC CLAYS AND ORGANIC SILTY CLAYS OF LOW w v = PLASTICITY z ~- - ~ = MH INORGANIC SILTS, MICACEOUS OR DIATOMACIOUS FINE ~ m SANDY OR SILTY SOILS, ELASTIC SILTS ~ _ _ z ~ SILTS AND CLAYS w ° ~ CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS LIQUID LIMIT GREATER THAN 50 OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS HIGHLY ORGANIC SOILS Pt ~, ~~~, PEAT AND OTHER HIGHLY ORGANIC SOILS 8 Modified California RV R-Value ® Split Spoon SA Sieve Analysis Pushed Shelby Tube SW Swell Test m Auger Cuttings TC Cyclic Triaxial ® Grab Sample TX Unconsolidated Undrained Triaxial Sample Attempt with No Recovery TV Torvane Shear CA Chemical Analysis UC Unconfined Compression CN Consolidation (1.2) (Shear Strength, ksf) CP Compaction WA Wash Analysis DS Direct Shear (20} (with % Passing No. 200 Sieve) PM Permeability ~ Water Level at Time of Drilling PP Pocket Penetrometer 1 Water Level after Drilling(with date measured} 0 a c7 of 3 Z N Z Z Z Z Q C7 J SOIL CLASSIFICATION CHART AND KEY TO TEST DATA Figure A-1 ~~~ ~~ E3RA, inc TEST PIT NUMBER TP-1 9802 - 29th Ave West, Suite 8102 Everett, Washington 98204 PAGE 1 OF 1 E3RA~~~ . Telephone: 425-356-3372 Figure A-2 Fax: 425-356-3374 CLIENT America's Credit Union PROJECT NAME Yelm Branch PROJECT NUMBER T07278 PROJECT LOCATION Yelm Washington DATE STARTED 10/10/07 COMPLETED 10/10/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Rock Crest Construction GROUND WATER LEVELS: EXCAVATION METHOD Track-mounted excavator AT TIME OF EXCAVATION -- LOGGED BY FER CHECKED BY JEB AT END OF EXCAVATION -- NOTES AFTER EXCAVATION -- w ~ 0= U F- W V? _ w~ ~ g ~ Q O ~ MATERIAL DESCRIPTION o ~ z j ~ ' ~ Q 0.0 '-"•: •` . Sod and silty sandy topsoil d ..~; ~ 1 ~ ri • ~T ~J . ~ .Q _ a w (SM) Dark brown silty fine sand with trace gravel (loose, damp) m :V ~ SM ;~. L .'' 9 •: • ~ . 2.5 ' • ~ •'. 3.0 (SP) Light brown gravelly sand with trace silt and scattered cobbles (loose to medium dense, moist) (Glacial Outwash) e ~_ L J C u J J 5.0 i 0 3 i SP :?~. 7.5 ::••. 9.0 No caving observed No groundwater seepage observed The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 9.0 feet. ~,~~ E3RA, Inc __ TEST PIT NUMBER TP-2 9802 - 29th Ave West, Suite 8102 Everett, Washington 98204 PAGE 1 OF 1 E3R ~, , ~~ Figure A-3 Telephone: 425-356-3372 Fax: 425-356-3374 CLIENT America's Credit Union PROJECT NAME Yelm Branch PROJECT NUMBER T07278 PROJECT LOCATION Yelm Washington DATE STARTED 10/10/07 COMPLETED 10/10/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Rock Crest Construction GROUND WATER LEVELS: EXCAVATION METHOD Track-mounted excavator AT TIME OF EXCAVATION -- LOGGED BY FER CHECKED BY JEB AT END OF EXCAVATION -- NOTES AFTER EXCAVATION -- w a >- ~ ~"- w ~ U S w ~ ~ g ~ ¢ O MATERIAL DESCRIPTION o Z ¢ I ~ ~ 0.0 ' ~: •` Sod and silty sandy topsoil • i :~: ~ti ~ ri _ ~i•~r4 .1.0 _ (SM) Dark brown silty fine sand with trace gravel and abundant roots to 2 feet (loose, damp) n ll O V SM J " 2.5 ~ ''. 3.0 (SP) Light brown gravelly sand with trace silt and scattered cobbles (loose to medium dense, moist) (Glacial Outwash) i i i i i i 5.0 SP 7.5 No caving observed No groundwater seepage observed The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 9.0 feet. c c q c 0 c s z u 3 a E3RA, Inc TEST PIT NUMBER TP-3 9802 - 29th Ave West, Suite 8102 E3~q,~~ Everett, Washington 98204 PAGE 1 OF 1 Telephone: 425-356-3372 Figure A-4 Fax: 425-356-3374 CLIENT America's Credit Union PROJECT NAME Yelm Branch PROJECT NUMBER T07278 PROJECT LOCATION Yelm_, Washington DATE STARTED 10/10/07 COMPLETED 10/10/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Rock Crest Construction GROUND WATER LEVELS: EXCAVATION METHOD Track-mounted excavator AT TIME OF EXCAVATION -- LOGGED BY FER CHECKED BY JEB AT END OF EXCAVATION - NOTES AFTER EXCAVATION - w = aw ~ v o ~ a ~ ~ ~ O MATERIAL DESCRIPTION ¢z ~ ~ 0.0 '-": •` ; Sod and silty sandy topsoil ~ : ~ • . i :~, r; J /j ~.Q (SM) Dark brown silty fine sand with trace gravel (loose, damp) n u 0 V SM 2.5 i ~ • 3.0 i i i (SP) Light brown gravelly sand with trace silt and scattered cobbles (loose to medium dense, moist) (Glacial Outwash) i 5.0 SP 7.5 No caving observed No groundwater seepage observed The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot. Bottom of test pit at 9.0 feet. c ~~ 6MP'(OL-8-Zl ahMS) 3-t~O104\s6u~MOJp\0~•{,O`0~\6ui~aaui6u3 punos\:p - wogt~l - OIOZ '60 ~a0 Western Washington Hydrology Model PROJECT REPORT Project Name: Site Address: City . Report Date Gage Data Start Data End Precip Scale: WWHM3 Version: SB1-IT 415 E Yelm Ave Yelm 12/6/2010 Lake Lawrence 1955/10/01 2008/09/30 0.86 PREDEVELOPED LAND USE Name SB1-PREDEV Bypass: No Groundwater: No Pervious Land Use Acres A B, Forest, Flat .702 Impervious Land Use Acres Element Flows To: Surface Interflow Name SB1-DEV Bypass: No Groundwater: No Pervious Land Use Acres A B, Lawn, Flat .22~ Impervious Land Use Aares ROOF TOPS FLAT 0.103 PARKING FLAT 0.373 Groundwater Element Flows To: Surface Interflow Groundwater SB1 Infiltration Trench, SB1 Infiltration Trench, Name SB1 Infiltration Trench ~~ Bottom Length: 142ft. Bottom Width Eft. Trench bottom slope 1: 0.001 To 1 Trench Left side slope 4: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer 0 Pour Space of material for first layer Material thickness of second layer 0 Pour Space of material for second layer Material thickness of third layer : 0 Pour Space of material for third layer Infiltration On Infiltration rate 20 Infiltration saftey factor 0.5 Discharge Structure Riser Height: 1.1 ft. Riser Diameter: 10 in. Element Flaws To: Outlet 1 Outlet 2 0 0 0 Gravel Trench Bed Hydraulic Table Stag®(f t) Area(acr) Volume(acr-ft) Dschr (efs) Inf9.lt(efs) 0.000 0.020 0.000 0.000 0.000 0.013 0.020 C.000 0.000 0.197 0.027 0.020 C.001 0.000 0.197 0.040 0.020 0.001 0.000 0.197 0.053 0.020 0.001 0.000 0.197 0.067 0.020 0.001 0.000 0.197 0.080 0.020 0.002 0.000 0.197 0.093 0.020 0.002 0.000 0.197 0.107 0.020 0.002 0.000 0.197 0.120 0.020 0.002 0.000 0.197 0.133 0.020 0.003 0.000 0.197 0.147 0.020 0.003 0.000 0.197 0.160 0.020 0.003 0.000 0.197 0.173 0.020 0.003 0.000 0.197 0.187 0.020 0.004 0.000 0.197 0.200 0.020 0.004 0.000 0.197 0.213 0.020 0.004 0.000 0.197 0.227 0.020 0.004 0.000 0.197 0.240 0.020 0.005 0.000 0.197 0.253 0.020 0.005 0.000 0.197 0.267 0.020 0.005 0.000 0.197 0.280 0.020 0.005 0.000 0.197 0.293 0.020 0.006 0.000 0.197 0.307 0.020 0.006 0.000 0.197 0.320 0.020 0.006 0.000 0.197 0.333 0.020 0.007 0.000 0.197 0.347 0.020 0.007 0.000 0.197 0.360 0.020 0.007 0.000 0.197 0.373 0.020 0.007 0.000 0.197 0.387 0.020 0.008 0.000 0.197 0.400 0.020 0.008 0.000 0.197 ~`~ 0.413 0.020 0.008 0.000 0.197 C.427 0.020 0.008 0.000 0.197 0.440 0.020 0.009 0,000 0.197 0.453 0.020 0.009 0.000 0.197 0.467 0.020 0.009 0.000 0.197 0.480 0.020 0.009 0,000 0.197 0.493 0.020 0.010 0.000 0.197 0.507 0.020 0.010 0.000 0.197 0.520 0.020 0.010 0.000 0.197 0.533 0.020 0.010 0,000 0.197 0.547 0.020 0.011 0.000 0.197 0.560 0.020 0.011 0.000 0.197 0,573 0.020 0.011 0.000 0.197 0.587 0.020 0,011 0.000 0.197 0.600 0.020 0,012 0,000 0.197 0.613 0.020 0.012 0.000 0.197 0.627 0.020 0.012 0,000 0.197 0,640 0.020 0.013 0.000 0.197 0.653 0,020 0.013 0,000 0.197 0.667 0.020 0.013 0.000 0.197 0.680 0,020 0.013 0,000 0.197 0,693 0.020 0.014 0.000 0.197 0.707 0.020 0.014 0,000 0.197 0,720 0,020 0,014 0,000 0.197 0,733 0,020 0.014 0.000 0.197 0,747 0.020 C.015 0.000 0.197 0 760 0.020 0.015 0,000 0.197 0.773 0.020 0.015 0.000 0.197 0.787 0.020 0,015 0.000 0.197 0.800 0.020 0.016 0.000 0.197 0,813 0.020 0.016 0.000 0.197 0.827 0.020 0.016 0.000 0.197 0.840 0,020 0.016 0.000 0.197 0,853 0.020 0.017 0.000 0,197 0,867 0.020 0,017 0.000 0.197 0.880 0.020 0.017 0,000 0.197 0.893 0.020 0.017 0.000 0.197 0.907 0,020 0.018 0,000 0.197 0.920 0.020 0,018 0,000 0.197 0.933 0.020 0.018 0.000 0.197 0.947 0,020 0.019 0.000 0.197 0.960 0.020 0,019 0.000 0.197 0.973 0.020 0.019 0.000 0.197 0.987 0.020 0.019 0.000 0.197 1.000 0,020 0,020 0.000 0.19'1 1.013 0.020 0.020 0.000 0.197 1.027 0,020 0,020 0,000 0.197 1,040 0.020 0.020 0.000 0.197 1.053 0,020 0.021 0,000 0.197 1.067 0.020 0.021 0.000 0.197 1.080 0,020 0.021 0,000 0.197 1.093 0.020 0.021 0.000 0.197 1.107 0.020 0.022 0.004 0.197 1.120 0.020 0.022 0.023 0.197 1,133 0.020 0.022 0.049 0.197 1.147 0.020 0.022 0.082 0.197 1.160 0.020 0.023 0,119 0.197 c-~} 1.173 0.020 0,023 0,161 0.197 1.187 0,02p 0.023 0,207 0,197 1.200 0,020 0.023 0,257 0,197 MI2'TGA`~ED LAND tJ aE ANALXSTS RESULTS Flow Frequency Re~uxn Periods for Predeueloper~, Ptah #1 Return Period Flow(c~'s) 2 year 0.001063 5 year 0.002951 1~ year 0,005442 25 year 0,011115 5U year 0,018255 1~0~0 year 0 , 029205 Flow Frequency Return Periods For Mitigated, POC #1 Return Period Flow(ofs3 2 year 0 5 yeax p lc~ year p 25 year p 5~ year p 100 year 0 Xearly Pea~ta ~'or Predeueloped and Ma.tigated, PDT #1 year Predeuelo ed Ma,ti ated 19.57 0,003 0,000 1958 0,001 0.000 1959 a,001 0,000 1960 0,001 0.000 1961 0,001 0,000 1962 0,003 0,000 1963 0,001 0,000 1964 0.001 0,000 1965 0,001 0,000 1966 0,001 0,000 1967 0,001 0,000 1968 0,001 0.000 1969 0-,001 0,000 1970 0,001 0,000 1971 0,001 0,000 1972 0,005 0.000 1973 0,007 0.000 1974 0,001 0,000 1975 0,002 0,000 1976 0,001 0,000 1977 0,001 0,000 1978 0,001 0,000 1979 0,001 0.000 1980 0,001 0,000 1981 0,001 0.000 C-S 19$2 0,001 0..000 1983 0,001 p,00p 19$9 0.001 0.000 19$5 0,001 0,000 19$6 0,001 0.000 1987 0,001 0.000 19$8 0.001 0,000 19$9 0,001 0,000 1990 0,001 0.000 1991 0,009 0,000 1992 0,006 0,000 1993 0,001 0,000 1999 0,001 0,000 1995 0,001 0,000 199E 0,003 0,000 1997 0,00$ 0,000 199$ 0,006 0,000 1999 0,001 0,000 2000 0,001 0,000 2001 0,001 0,000 2002 0,000 0,000 2003 0,003 0,000 2009 0,001 0,000 2005 0,036 0.000 2006 0,006 0,000 2007 0,026 0,000 2008 0,011 0,000 2009 0.001 0,001 ~~~e~. X~arly k~~a7~s ~c~x ~.reci~v~l,vge~l ~.z~d Mitis~a~~s~, k~U~ ~~ ~~~ ~x~es~,~v~loped Ma.~iga~~~i. 1 0,0369 0,000$ 2 0,0257 0,0000 3 0,0110 0,0000 9 0,00$5 0.0000 5 0,0079 0,0000 6 0,0062 0,0000 7 0,0061 0,0000 $ 0 , 00.56 0 , 0000 9 0,0096 0,0000 10 0,0090 o,0ooa 11 0.0005 0,0000 12 0,00.35 0.0000 13 0,0030 0,0000 19 0,0025 0,0000 15 0,0019 0..0000 16 0,0019 0,0000 17 0,0013 0,0000 18 0,0013 0,0000 19 0,0010 0,0000 20 0,0012 0,0000 21 0,0009 0,0000 22 0,0008 0,0000 23 0,0008 0,0000 29 0,000$ 0,0000 25 0,0006 0,0000 C~ b 26 0.0006 0.0000 27 0.0006 0.0000 28 0.0006 0.0000 29 0.0006 0.0000 ~ 30 0.0006 0,0000 31 0.0006 0,0000 ~ 32 0.0006 0.0000 33 0.0006 0.0000 34 0.0006 0,0000 ~ 35 0.0006 0.0000 36 0.0006 0.0000 37 0.000'0 0,0000 38 0.0006 0.0000 39 0.0006 0.0000 40 0.0006 0,0000 41 0.0006 0.0000 42 0.0006 0.0000 ~ 43 0.0006 0.0000 44 0.0006 0.0000 45 0.0006 0.0000 46 0.0006 0.0000 47 0.0005 0,0000 48 0,0005 0.0000 l 99 0,0005 0.0000 50 0.0005 0.0000 51 0.0005 0,0000 52 0.0005 0.0000 ` 53 0,0005 0.0000 ~~ #~ ~ The Facility PASS &D The Facility PASSED- ~ Flow(CFS) Pxedev Dev Pexcentage PassjFail . 111 O~pp05 691 2 0 Pass 0,0007 148 2 1 Pass 0.0009 120 0 0 Pass i 0,0011 97 0 0 Pass 0,0012 80 0 0 Pass 0,0014 61 0 0 Pass 0,0016 51 0 0 Pass 0.0018 1) 48 0 0 Pass 0.0020 44 p 0 Pass - 0.0021 38 0 0 Pass ~ 0,0023 37 0 0 Pass 0.0025 34 0 0 Pass 0.0027 32 0 0 Pass 0,0029 30 0 0 Pass 0,0030 28 0 0 Pass 0.0032 26 0 0 Pass 0.0034 25 0 0 Pass 0.0036 21 0 0 Pass 0.0038 19 0 0 Pass 0,0039 18 0 0 Pass 0.0041 l 16 0 0 Pass c.-~ a.aa~8 16 a p Pass a,aa4.5 14 a a Pass a.aa~p 13 a a Pass a,aa48 11 a a Pass a.aa.~a ~ a a ~~,~,~ a.a0~2 9 a a Pass a, aa.~~ ~ a a ~~~~ a ~ aa.~~ ~ a a Pass a.aa57 8 a a Pass a,aa~9 7 a a Pass a,aa61 ~ a a Pass a,aa~a .~ a a ~~~~ a,aa~~ ~ a a ~~~~ a,aa~~ 5 a a Pa~~s a.aa~8 5 a a Pass a,aa7a ,~ a p Pass a.aa72 5 a a Paa,s a,aa73 a a a Paa~ a.aa7~ ~ a a Pais a.aa77 4 a a Pass a.aa7Q ~ a a Pa~~ a,aaul ~ a a Pais a.aQ82 ~ a a Pass a,a08~ ~ a a :Pass a,aas~ a a a ~~~~ a,aaaa ~ a a ~~~~ a.aa89 3 a a Pa~s~ a.aa91 3 a a Pa,s,s a.aa~~ ~ a a Pa~~ a.aa~.~ a a a Pais a,aa~7 ~ a a Pass a,aa~a a a a Pa~~ a.,alaa 3 a a Pais a.a1a2 ? a a Pass a,a1a9 ~ a a Pais a,a1a~ ~ a a Pass a.a1a7 ~ a a Pass a,a1a~ ? a a Pass a,a111 2 a a Pais a,a11~ 2 a a Pais a,a11~ 2 a a Pang a,a11~ 2 a a Pass a,a11$ 2 a a Pa~~ a.Q12a 2 a a Pa~~ a,a122 2 a a Pa,s~ a,a123 2 a a Pa~~ a,a12~ 2 a a Pass a,a127 2 a a Pass a.a12~ 2 a a Pass a,a1~1 2 a a Pa~~ a,a1~2 2 a a Pass a.a1~4 2 a a Pass a,a1~~ 2 a a Pa~~ a.a13~ 2 a a Pais a. a1~#a 2 a a Pa~s~ a,a141 2 a a Pass O.a143 2 a a Pa~~ c-8 0.0145 2 0 0 Pass 0..0147 2 0 0 Pass 0.0149 2 p 0 Pass 0.0150 2 0 0 Pass 0.0152 2 0 0 Pass 0.0154 2 0 0 Pass 0,0156 2 0 0 Pass 0.0157 2 0 0 Pass 0,0159 2 0 0 Pass 0.0161 2 0 0 Pass 0..0163 2 0 0 Pass 0.0165 2 0 0 Pass 0.0166 2 0 0 Pass 0,0168 2 0 0 :Pass 0.0170 2 0 0 Pass 0,0172 2 0 0 Pass 0.0174 2 0 0 Pass 0.0175 2 0 0 Pass 0.0177 2 0 0 Pass 0.0179 2 0 0 Pass 0.0181 2 0 0 Pass 0,0183 2 0 0 :Pass t9a~ex Quala~y ~kiP k'lsax~ azad +7c1?am~ ~'cax ~O~ ~. On-laa~ a'a~ala~X vralzau~e,; Q acre-Eeek Ozz-lama ~acala~y ~axg~~ ~lQ~v : Q . (J ]. ~~s . .Adax~~kad fox la ~ni,zz: ~ s~~s . ~~'~-lazz~ ~'a~ala~~ fiax~a~ ~los~; U cis. ,Ad~?a~~~~l ~'ox l~ >xtzzx: ~ ~~'~, ~~x.lz~~ az~d ~znp],x~~. ~haz~c~~s ~~ ck~ang~s hart" b~;eza ma~~. ^thi,7 ~;x<~c~ran~ and ac.uampanyi.n:~ dac.utnenkaxl.an i. ~yrc~v7,cieci 'a.a-i,' ;v.iklta~~ warxainry ca arty k.i,ttd, `Plie en~7,re xirk reyax•c:~inc~ rtie s~r~rrUrmrtnc;~: az3,i r.~?r~a.],ts cst r„itiU px~cac~z~am ira ;~r~u~am~cl day ~hP u.aer•, C,l,eax C;:xeek upl.u~icjn.~ aztci khe i~7a~sttin~zazt .~ka~e Ae~arknienx <~t Ec.<)1c;~y cii:>c,luims all. ~zarxuntiez;, eikhex~ ex~xeUZ;eci Ux im~ilieci, 3.ns:luding buz npX 11mitPCi ~p i.rn~~ller~ sNa.rranT;ie., aF ~ra~ram and ac:c;c7mpany.l.nc~ dcyc.uncenzaki,Un, Tn nc> avenk ;;t,a11 !,"l,Ar~x l:cePk ~c>1~ai;i,gn~ acid/car zhP INa,stiint~~Un uzaire p~~r~x°~mPztY, cif Eca1c>gy YEA li,,~b1r: tvx arty ciamur~r:r, wit;~tzpPv?x (inc. l.u~d.lzty ~ii~tiau~ ],.l.ntiY.~ric>n tc~ cianiay~s E<~r 1c>c>c; of buuin~;~u pecit~,t., 7,<~tsr; OF b!az~i,nez~~ in~c~xma~l.an, bu~inr:at~ inZerxu~s?:ic~n, anci rte like) arirtincx Uuk ar zhe u.~e c>r, c>r inaYsi,Zl.ty to u ~e Zttis pxUrizam even i.f Clear Cx•eek Sc~luticjnE~ Ur Gltc: ylactiin:~~an Szure ue~~arzmenk <~f Eu<j].ci~y ha.~ been <advi~eci csE ttic: pUC;tsi,fa2lizy yr ~?ac;tt dattu~c~er. ~~ Western Washington Hydrology Model PRO.JEAR' REPAR'I' Project Name: SB2-IT Site Addrass, 915 E Ye1m Ave pity Ye1m Report Aate 12/6/2Q1fJ Gage Lake La;arence Rata Start , 1955/1Q/p1 Aata End 2pp8/Q9/3p Precip Scale, p.86 WWHM~ version: PREAEVET.~OPEA T,AND USE Name SB2-PRBDEV Bypass; No GxoundWatex. No Pexvxoi~s nand Use Acres ,~ ~, Forest, Flat .4$ Tmpex~rious T~ans~ Use Acres Element Floes ~o~ S~zx~ace xnter~low Name SB2-BB~T Bypass ~ 2~c Gxo~zx~d~latex ; Nc~ Pexvio?as z,ans~ Use Acres A ~, Lawn, Flat , t~37 Tmpexvious T,and Use Acres RoAF 1'QPS FT,Fl~'I' ~ , d~22 PARfCING FT,AI' t~ , X21 Gxo~ndwater Element Flows Toy Suxfaca xnter~low Groa~n~.watar SB2 InFiltratic~n Trench, SB2 Infiltratiran Trench, Noma SB2 In~iltratic~n Trench C-~ b Bottom Length: 14ft. Bottom Width : Eft, Trench bottom slope l: 0.001 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer : 0 Pour Space of material for first layer : 0 Material thickness of second layer 0 Pour Space of material for second layer : 0 Material thickness of third layer : 0 Pour Space of material for third layer : 0 Infiltration CJn Infiltration rate : 20 Infiltration saftey factor : 0,5 Discharge Structure Riser Height: 1.1 ft. Riser Diameter: 10 in. Element Flows To: outlet 1 Outlet 2 Grauel Trench Bed Hydraulic Table Stag®(ft) ~r~a(a~x) Volv~ixie(a~x-Et) A~ahxa(~ta) ZnEi,lt(~£a) 0.000 0.002 0.000 0.000 0,000 0.013 0.002 0.000 0.000 0.019 0.027 0,002 0.000 0,000 0,019 0.040 0.002 0,000 0.000 0.019 0,053 0,002 0,000 0.000 0.019 0.067 0.002 0.000 0.000 0.019 0.030 0.002 0,000 0,000 0,019 0.093 0.002 0.000 0,000 0.019 0.107 0.002 0,000 0,000 0,019 0,120 0,002 0,000 0,000 0.019 0,133 0.002 0,000 0,000 0,019 0.147 0.002 0,000 0,000 0,019 0.160 0,002 0.000 0,000 0.019 0.173 0.002 0,000 0,000 0.019 0,187 0.002 0,000 0.000 0.019 0,200 0,002 0,000 0.000 0,019 0,213 0,002 0,000 0,000 0.019 0,227 0.002 0,000 0,000 0.019 0.240 0.002 0,000 0,000 0.019 0.253 0.002 0,000 0,000 0.019 0.267 0.002 0,001 0,000 0,019 0.280 0,002 0,001 0.000 0.019 0.293 0.002 0,001 0.000 0,019 0,307 0.002 0,001 0.000 0.019 0.320 0.002 0.001 0,000 0,019 0.333 0.002 0.001 0,000 0.019 0.347 0.002 0,001 0,000 0.019 0.360 0,002 0,001 0,000 0.019 0.373 0.002 0.001 0.000 0.019 0.387 0.002 0,001 0,000 0.019 0.400 0.002 0.001 0.000 0.019 ~~ 0.413 0.002 0.001 0.000 0.019 0.427 0.002 0.001 0,000 0,019 0.440 0.002 0.001 0,000 0.019 0.453 0,002 0.001 0,000 0.019 0,467 0.002 0.001 0.000 0.019 0.480 0.002 0,001 0.000 0.019 0.493 0.002 0.001 0,000 0.019 0.507 0.002 0.001 0.000 0.019 0.520 0.002 0,001 0.000 0,019 0.533 0.002 0.001 0.000 0.019 0.547 0.002 0.001 0.000 0.019 0,560 0.002 0.001 0.000 0.019 0.573 0,002 0,001 0,000 0.019 0.587 0,002 0,001 0.000 0.019 0.600 0.002 0,001 0.000 0.019 0,613 0.002 0,001 0.000 0.019 0.627 0,002 0,001 0.000 0.019 0.640 0.002 0,001 0.000 0.019 0.653 0.002 0,001 0,000 0.019 0.667 0.002 0,001 0.000 0.019 0.680 0,002 0,001 0,000 0.019 0,693 0.002 0,001 0.000 0.019 0.707 0.002 0,001 0.000 0,019 0,720 0.002 0,001 0.000 0.019 0.733 0,002 0,001 0,000 0,019 0,747 0.002 0,001 0.000 0.019 0.760 0.002 0,001 0.000 0,019 0.773 0,002 0,001 0.000 0.019 0,787 0,002 0,002 0.000 0.019 0.800 0,002 0,002 O,OGO 0.019 0,813 0,002 0,002 0,000 0,019 0,827 0.002 0,002 0.000 0.019 0.840 0,002 0,002 0,000 0.019 0,853 0.002 0,002 0.000 0,019 0,867 0.002 0.002 0,000 0,019 0,880 0.002 0,002 0,000 O.C19 0,893 0,002 0.002 0.000 0.019 0,907 0.002 0,002 0.000 0,019 0,920 0.002 0,002 0,000 0.019 0,933 0.002 0,002 0.000 0,019 0,947 0,002 0,002 0,000 0,019 0,960 0.002 0.002 0.000 0.019 0,973 0.002 0,002 0,000 0.019 0.987 0.002 0.002 0.000 0.019 1,000 0.002 0,002 0,000 0.019 1.013 0.002 0,002 0.000 0.019 1,027 0,002 0,002 0,000 0.019 1,040 0.002 0.002 0.000 0,019 1.,053 0.002 0,002 0,000 0.019 1,067 0.002 0,002 0.000 0.019 1.080 0.002 0,002 0.000 0.019 1,093 0.002 0.002 0.000 0.019 1.107 0,002 0.002 0.004 0.019 1,120 0.002 0.002 0.023 0.019 1.133 0.002 0,002 0.049 0.019 1.147 0.002 0,002 0.082 0.019 1.160 0.002 0,002 0.119 0.019 ~°" t 1.173 0.002 0.002 0.161 0.019 1.187 0.002 0.002 0.207 0.019 1.200 0.002 0.002 0.257 0.019 MITIGATED LAND USE ANALYSIS RESUT,TS Flaw Frequency Return Periods far Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.000121 5 year 0.000336 14 year 0.00062 25 year 0.001267 54 year 0.00208 144 year 0.003328 Flaw Frequen cy Return Periods far Mitigated. P9C #1 Return Period Flow(cfs) 2 year p 5 year 0 14 year 0 2b year p 50 year p 140 year 0 Yearly Peaks far Predeveloped and Mitigated, PrJC #1 Year Predevela ed Miti ated 1957 0,000 0.000 1958 0,000 0.000 1959 0,000 0,000 1960 0,000 0,000 1961 0,000 0,000 1962 0.000 0.000 1963 0,000 0.000 1964 0,000 0.000 1965 0,000 0.000 1966 0.000 0.000 1967 0.000 0.000 1968 0,000 0,000 1969 0.000 0,000 1970 0,000 0.000 1971 0.000 0.000 1972 0,001 0.000 1973 0.001 0.000 1974 0.000 0.000 1975 0.000 0,000 1976 0.000 0.000 1977 0.000 0.000 1978 ~ 0.000 0.000 ' 1979 0.000 0.000 1980 0,000 0.000 1981 0.000 0.000 ~~ 6 1982 0.000 0,000 1983 0.000 0,000 1984 0.000 0,000 1985 0.000 0,000 1986 0.000 0,000 1987 0.000 0,000 1988 0.000 0,000 1989 0.000 0.000 1990 0.000 0,000 1991 0.000 0,000 1992 0.001 0,000 1993 0,000 0.000 1994 0.000 0.000 1995 0.000 0.000 1996 0.000 0,000 1997 0,001 0,000 1998 0.001 0.000 1999 0.000 0.000 2000 0.000 0.000 2001 0,000 0.000 2002 0.000 0.000 2003 0.000 0.000 2004 0,000 0.000 2005 0 004 0,000 2000 0,001 0,000 2007 0.003 0.000 2008 0.001 0.000 2009 0,000 0,000 Ranked, Yearly Peaks For Pre~ievel4ped az~d, Mitiga~e~i. PQ~ #1 Rank Predevelc~ped Miti~a~ed 1 0.0042 0,0000 2 0.0029 0.0000 3 0.0013 0,0000 4 0.0010 0,0000 5 0,0008 0,0000 6 0.0007 0.0000 7 0,0007 0,0000 8 0,0006 0,0000 9 0,0005 0,0000 10 0.0005 0.0000 11 0.0004 0,0000 12 0.0004 0,0000 13 0,0003 0,0000 14 0.0003 0,0000 15 0.0002 0,0000 16 0,0002 0,0000 17 0.0002 0,0000 18 0.0001 0.0000 19 0.0001 0.0000 20 0.0001 0,0000 21 0,0001 0,0000 22 0.0001 0.0000 23 0.0001 0.0000 24 0.0001 0.0000 25 0.0001 0,0000 Gl~ 26 0.0001 0.0000 27 0.0001 0.0000 28 0.0001 0.0000 29 0.0001 0.0000 30 0.0001 0.0000 31 0.0001 0.0000 32 0.0001 0.0000 33 0.0001 0.0000 34 0.0001 0.0000 35 0.0001 0.0000 36 0.0001 0.0000 37 0.0001 0.0000 38 0.0001 0.0000 39 0.0001 0.0000 40 0.0001 0.0000 41 0.0001 0.0000 42 0.0001 0.0000 43 0.0001 0.0000 44 0.0001 0.0000 4~ 0.0001 0.0000 46 0.0001 0.0000 47 0.0001 0.0000 48 0.0001 0.0000 49 0.0001 0.0000 50 0.0001 0.0000 51 0.0001 0.0000 52 0.0001 0.0000 53 0.0001 0.0000 POC #1 The Facility PASSED The Facility PASSED. Flow(CFS) Predev Dev Percentage Pass/Fail 0.0001 757 0 0 Pass 0.0001 149 0 0 Pass 0.0001 120 0 0 Pass 0.0001 97 0 0 Pass 0.0001 80 0 0 Pass 0.0002 61 0 0 Pass 0.0002 52 0 0 Pass 0.0002 48 0 0 Pass 0.0002 44 0 0 Pass 0.0002 38 0 0 Pass 0.0003 37 0 0 Pass 0.0003 34 0 0 Pass 0.0003 32 0 0 Pass 0.0003 30 0 0 Pass 0.0003 28 0 0 Pass 0.0004 26 0 0 Pass 0.0004 25 0 0 Pass 0.0004 21 0 0 Pass 0.0004 19 0 0 Pass 0.0004 18 0 0 Pass 0.0005 16 0 0 Pass C- t 5 0.0005 16 0 0 Pass 0.0005 15 0 0 Pass 0.0005 13 0 0 Pass 0.0006 11 0 0 Pass 0.0006 9 0 0 Pass 0.0006 9 0 0 Pass 0.0006 9 0 0 Pass 0.0006 9 0 0 Pass 0.0007 8 0 0 Pass 0.0007 7 0 0 Pass 0.0007 6 0 0 Pass 0.0007 5 0 0 Pass 0.0007 5 0 0 Pass 0.0008 5 0 0 Pass 0.0008 5 0 0 Pass 0.0008 5 0 0 Pass 0.0008 5 0 0 Pass 0.0008 5 0 0 Pass 0.0009 4 0 0 Pass 0.0009 4 0 0 Pass 0.0009 4 0 0 Pass 0.0009 4 0 0 Pass 0.0009 4 0 0 Pass 0.0010 4 0 0 Pass 0.0010 3 0 0 Fass 0.0010 3 0 0 Pass 0.0010 3 0 0 Pass 0.0010 3 0 0 Pass 0.0011 3 0 0 Pass 0.0011 3 0 0 Pass 0.0011 3 0 0 Pass 0.0011 3 0 0 Pass 0.0011 3 0 0 Pass 0.0012 3 0 0 pass 0.0012 3 0 0 Pass 0.0012 3 0 0 Pass 0.0012 3 0 0 Pass 0.0012 3 0 0 Pass 0.0013 2 0 0 Pass 0.0013 2 0 0 Pass 0.0013 2 0 0 Pass 0.0013 2 0 0 Pass 0.0013 2 0 0 Pass 0.0014 2 0 0 Pass 0.0014 2 0 0 Pass 0.0014 2 0 0 Pass 0.0014 2 0 0 Pass 0.0014 2 0 0 Pass 0.0015 2 0 0 Pass 0.0015 2 0 0 Pass 0.0015 2 0 0 Pass 0.0015 2 0 0 Pass 0.0015 2 0 0 Pass 0.0016 2 0 0 Pass 0.0016 2 0 0 Pass 0.0016 2 0 0 Pass 0.0016 2 0 0 Pass C_1 ~ 0.0017 2 0 0 Pass 0.0017 2 0 0 Pass 0.0017 2 0 0 Pass 0.0017 2 0 0 Pass 0.0017 2 0 0 Pass 0.0018 2 0 0 Pass 0.0018 2 0 0 Pass 0.0018 2 0 0 Pass 0.0018 2 0 0 Pass 0.0018 2 0 0 Pass 0.0019 2 0 0 Pass 0.0019 2 0 0 Pass 0.0019 2 0 0 Pass 0.0019 2 0 0 Pass 0.0019 2 0 0 Pass 0.0020 2 0 0 Pass 0.0020 2 0 0 Pass 0.0020 2 0 0 Pass 0.0020 2 0 0 Pass 0.0020 2 0 0 Pass 0.0021 2 0 0 Pass 0.0021 2 0 0 Pass Water Quality HMP Flow and Volume for P00 1. On-line facility volume: 0 acre-feet On-line facility target flow: 0.01 cfs. Adjusted for 15 min: O.C013 efs. Off-line faoility target Flow: 0.0011 efs. Adjusted for 15 min: 0.0011 cfs. Perlnd and Tmplnd Changes No changes have been made. This program and accompanying documentation is provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by the user. Clear Creek Solutions and the Washington State Department of Ecology disclaims all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions or the Washington State Department of Ecology has been advised of the possibility of such damages. c-~~ APPENDIX D Water Quality Treatment SEI Western Washington Hydrology Model PROJECT REPORT Project Name: SB1-WQ Site Address: 415 E Yelm Ave City Yelm Report Date 12/5/2010 Gage Lake Lawrence Data Start 1955/10/01 Data End 2008/09/30 Precip Scale: 0,86 WWHM3 Version: PREDEVELOPED LAND USE Name SB1-PREDEV Bypass: No Groundwater: No Pervious Land Use Acres A B, Forest, Flat .375 Impervious Land Use Acres Element Flows To: Surface Tnterflow Name SB1-DEV Bypass: No Groundwater: No Pervious Land Use Acres Impervious Land Use Acres PARKING FLAT p.373 Groundwater Element Flows To: Surface Tnterflow Groundwater MITIGATED LAND USE ~~ ANALYSIS RESULTS Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.000565 5 year 0.001568 10 year 0.002891 25 year 0.005906 50 year 0.009699 100 year 0.015518 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.155544 5 year 0.211319 10 year 0.252235 25 year 0.308654 50 year 0.354234 100 year o.4oz963 ~- Sub basin 1 100-yr flow rate Water Quality BA7P Flow and Volume for POC 1. On-line facility volume: 0.0542 acre-feet On-line facility target flow: 0.01 cfs. Adjusted for 15 min: 0.0645 afs. ~ Sub basin 1 1Nater Quality flow rate Off-line facility target flow: 0.0366 efs. Adjusted for 15 min: 0.0366 afs. Perlnd and Imglnd Changes No changes have been made. This program and accompanying documentation is provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by the user. Clear Creek Solutions and the Washington State Department of Ecology disclaims all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentati.or.. In no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions or the Washington State Department of Ecology has been advised of the possibility of such damages. ®~ America's Credit Union Sub Basin 1 Biofiltration Swale Calculations INPUT DATA O ~ 0.0645; cfs From WWHM report, WQ section S ~j_ 1.5~% Assumed slope y (depth) f~ (yin ' Assumed depth (2" max if mowed frequently, 4" max if mowed infrequently) Side slope 3 3:1 n 0.24; Manning coefficient residence time 9i min For continuous inflow K k ~ 2.2; From 2005 DOE, voL V, Figure 9.6a (Ratio of SBUH Peak/WQ Flow DESIGN RESULTS bottom width = 2 ft Use bottom width = ~ ft top width = 4 ft Top width at water surface Area = 1 ft2 Flow area velocity = 0.14 ft/sec < 1 ft/sec [OK] length = 100 ft (calculated L = 76 ft) CHANNEL STABILITY Q __0644741 j cfs 1.6 x 100-year W WH M flow rate (2005 DOE, vol. V, p. 9-11) Vmax ~ 3~ fUsec n (trial) ~ 0.047 trial Manning's n for high flow condition VR (approx.) _ ~ 2 ft2/sec From 2005 DOE, vol. V, Figure 9-7 STABILITY RESULTS VR (actual) = 1.97 ft2/sec R = 0.52 ft T= 7ft Velocity = 3 fUsec <= 3 ft/sec [OK] depth = 10 in (includes 0.5' of freeboard) Q (capacity) = 1.83 ft3/sec > .6447408 cfs [OK] D-3 SBUH PeakIWWHM On-Line 15-min WQ Flow Ratio vs 6-Month Precipitation for 0% to 100°lo Impervious Areas 4.5 4.0 R 3.5 a t 3.0 0 2.5 - {K) 2.0 ~~ 1 5 6-month 24-hr storm = 72% of 2- r 24-hr storm = 0.72 x 2.1" = 1.51" 1.0 0.5 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 6-month, 24-hr precipitatian {72% of 2-year), Inches Figure 9.6a - Ratio of SBUH PeakNVQ Flow SBUH Peak/WWHM Off-Line 15-min WQ Flow Ratio vs 6-Month Precipitation for 0% to 100% Impervious Areas 8.0 R 7.0 t 6.0 i 5.0 0 {K) 4.0 3.0 2.0 1.0 - i 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 6-month, 24-hr precipitation {72% of 2-year), Inches Figure 9.6b - Ratio of SBUH PeaktWQ Ftow 4) Reduce the developed surface area to gain space for biofiltration. 5) Increase the longitudinal slope. 9-1 D Volume V - Runoff Treatment BMPs February 2005 -~ STORMWATNR MANAGNh1~NT MANUAL FOR TH); PUG~T SOi7ND BASIN Tao ~a3 ~a~ ia~ 49 ~P. {'~ = ~~ ~.~ ~' ~~, ~ ~ 25 m 25 n ~~ o w c~ ~ ca ttttnsa r~ ~ m ~~~~: • ~ 2 ~ ~ GAEL s~ r~ OLGA ,~ \ ` ` ~ . s~1 iry"' , ~ ffb FRIDAY HARE R ) l ~ )n ~ ' PORT STA LEY Z~ C~ / ~ R( 11 T ~ ;~ as ~~~ ~~>3-___ i / I5 ERETT~ `2~~; ', . ~ ti S a5 '~ ~ s aT _ s~ ' ~~ ~. .f ~," '~ •5 ~i e~t~ .. 3 D5 ~~ :~ ~ ~.. ~ ~\~. 3 a5 r ' ~~ - ~ . 47 °°` - - .9 ~', ••~ HB RDE N `'~ ~ ~ 0 ' - 3D - ~ ~ v ~ a 4U ° CENT e , ~ a i4'~ 2t) a ~ ~ O ~. ~ ~ ~ ~' 1D YAIU ~' ao t ~ ., 35 4~~~ ~ iaDArr ~ 3 2 L- • ~' ~s t lll~r~DU~II~~ U ©~ ~n ._. ~ •35 ~ e K . ~ -- RPL 66 E N E to o l0 20 3o no , - ~ '~~ ~ '~ ~ r z •~°, PARES ~i ~ i ` ~ ~ j i L'rhD ~ `~~' 25~,~ ~ i^- NOAH AYLAS 2, Voluma IX ISOPLW1Al•S F 2.1'R 2Q-FIR PRECIPIT'ATI N IN Preporod by U.S. Dopor4man4 oP C morce TENTHS ®F A lNOH NationolOceanlcondAtmonphorie ministrutlon Notionol lVenthar Sorvico, Officn of Hydrology Proporcd 4or U.S. Dnportmen4 of A riculture, Solt Conoervotion Service, Enginoor ng Division ~a~ ins Paz 22~ p -5 Western Washington Hydrology Model PROJECT REPORT Project Name: SB2-WQ Site Address: 415 E Yelm Ave City Yelm Report Date 12/5/2010 Gage Lake Lawrence Data Start 1955/10/01 Data End 2008/09/30 Precip Scale: 0.86 WWHM3 Version: PREDEVELOPED LAND USE Name SB2-PREDEV Bypass: No Groundwater: No Pervious Land Use Acres A B, Forest, Flat .021 Impervious Land Use Acres Element Flows To: Surface Tnterflow Groundwater Name SB2-DEV Bypass: No Groundwater: No Pervious Land Use Impervious Land Use PARKING FLAT Acres Acres 0.021 Element Flows To: Surface Tnterflow Groundwater MITIGATED LAND USE p~~ ANALYSIS RESULTS F1pw Frequency Return Periods for Return Feripd Flpw{cfs) 2 year 0.000032 5 Year 0.000088 10 year 0.000163 25 year 0.000333 50 Year 0,000596 100 year 0.000879 Flow Frequency Return Periods fpr Predeveloped. POC #1 Mitigated. POC #1 Return Feripd Flpw(cfs) 2 Year 0.008757 5 year 0.011897 10 year 0.014201 25 yeax 0.017377 50 yeax 0,019943 100 yeax 0,022687 water Quality HMP Flgm and vglume Eqr PAC 1. Online facility vglume; O.p03 acre-feet On-line (agility target flaw: 0,01 cfa, Adjusted fqr 15 min: 0.0036 cfs. ~l,lb ~~Sif1 2 U1l~t~r ~u~lity flow r~t~ Aff~line Facility target flaw: 0,pg2 cfs. Adjusted far 1S min: 0,002 cP:s. Pexlnd and Im~alnd Ohanges No chane~es have been made. This program and accompanying documentation is provided 'as-is' without warranty of any kind, The entire risk regarding the performance and results of this program is assumed by the user. Clear Creek Solutions and the Washington State Department of Ecology disclaims all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. 1n no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable for any damages whatsoever {including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions or the Washington State Department of Ecology has been advised of the possibility of such damages. # of Stcrr~filter partridges req'd =1NC~ flca~v{cfs) x (~4~ gpm/cfs) / {7,~ gprr~/cartridge) = 0.~0~~ x ~~9 / 7.5 = Q.22 ~-~ use 1 cartridge `~ B C 2 OUTLET STUB (SEE NOTES 4~5) 10" 6" OVERLAP • '.o' ~ A n p' q 9 4 A •• •9 U1EIR NJALL o a: • Q• .e .~ ~ : .. ~ ~•.p •. ,• . q• . . I I 1•' • -•. SCUM BAFFLE • o o.: a • A A .D 4 1 G A A> A , •'A , .. e. .- ~ ••• •9,. P ~. .. • ~ ~ 0. q• . s . r. n L `A ' ~% 9 . •QA q•• s, G 4 • q •. 'p M .Q ~ q , • Q 9 , INLET STUB REINFORCING BARS (OPTIONAL) - (5EE NOTE 6) (5EE NOTES 4~5) 1-CARTRI®GE CAT~HBASIN - Pl-AN VIEW 1 1 ~ ~ ACCESS COVER INLET GRATE ~ pPENiNG t- 2 !/2" o" ~~ • oA . 4' n ~I' - CONCRETE COLLAR OUTLET 5TUB (SEE NOTE 6) (SEE NOTES 4~5) / ~ ~ ~ STORMFILTER CARTRIDGE (TYP) CLEANOUT ACCE55 (SEE NOTE 2) PLUG ON WEIR WALL UNDERDRAIN MANIFOLD IN51DE IN51DE 4'-4 3/4" OUT5IDE Tt1E STORMWATER MANAGEMENT 1-CARTRIDGE CATCHBASIN - SECTION VIEW A 9CormPilter~ U.S. PATENT No. 5,322,629, 1 No. 5,707,527: Nv. 6,027,639 No. 6,6B9,Oh8, No. 5,624,S76, AND OTFIER U.S. AND FOREIGN ©2006 CONTECH Stomlwater Solutions PATENTS PENDING A~V~CA1..1® STEEL CATCHBASIN ST©RMFILTER DfzaWlNc f>i ~1-~ ~ i~:7 STORMWATER PLAN AND SECTIION VIEWS ~ SOLUTIONS STANDARD DETAIL - 1 CAR°fRIDGE UNIT 13 contechstormwater.com DATE: 11/01/05 SCALE:NONE FILENAME:CBSFIS-DTL DRAWN:MJW CHECKED:ARG 0 4"OJ OPENING PERMANENT POOL ELEVATION I I' VARIES 2'-3 5/8" MAX. INLET STUB {OPTIONAL) (SEE NOTES 4~ 5) OUTLET STUB (SEE NOTES 4~ 5) 2'-0 112" ~ ~- 2"(d OUTLET PIPE OUTSIDE PROM UNDERDRAIN TRIDGE CATCI-(BASIN -SECTION VIEW >~1 2'-3 5/8" LIFTING EYE (TYP OF 4) ~ PERMANENT 3~_g~~ POOL ELEVATION - - _..~ CARTRIDGE I '-6" SUPPORT (TY1P) 1 1-CARTRIDGE CATCNBASIN -SECTION VIEW C 2 THE STORM WATER MANAGEMENT StarmFlter~ U.S. PATENT No. 5,322,629, No. 5,707,527, No. 6,027,639 No. 6,649,048, Na. 5,624,576, AND Oif1ER U.S. AND FOREIGN ©2006 CONTECH Stolmwater Solutions PATENTS PENDING A~~~ITCAL~® STEEL CATCHBASIN STORMFILTER DRAWIN( SECTION VIEWS 2 STORMWATER SOLUTIONS STA~9DARD DETAIL - 1 CARTRIDGE UNIT ti3 contechstormwateccom DATE: 11/01/05 SCALE:NONE FILE NAME:CBSFIS•DTL DRAWN:MJW CHECKED:ARG D~~ GENERAL NOTES I) STORMFILTER BY CONTECH STORM WATER SOLUTIONS; PORTLAND, OR (800) 548-4667; SCARBOROUGH, ME (877) 907-8676; ELKRIDGE, MD (866) 740-33 18. 2) FILTERS TO BE SIPHON-ACTUATED AND SELF-CLEANING. 3) STEEL STRUCTURE TO BE MANUFACTURED OF I/4 INCH STEEL PLATE. 4) STORMFIL.TER REQUIRES 2.3 PEST OF DROP FROM RIM TO OUTLET. INLET SHOULD NOT BE LOWER THAN OUTLET. INLET (IF APPLICABLE) AND OUTLET PIPING TO BE SPECIFIED BY ENGINEER AND PROVIDED 8Y CONTRACTOR. 5) CBSF EQUIPPED WITH 4 INCH (APPROXIMATE) LONG STUBS POR INLET (IF APPLICABLE) AND OUTLET PIPING. STANDARD OUTLET STUB IS S INCHES IN DIAMETER. MAXIMUM OUTLET STUB IS 15 INCHES IN DIAMETER. CONNECTION TO COLLECTION PIPING CAN BE MADE USING FLEXIBLE COUPLING BY CONTRACTOR. 6) FOR H-20 LOAD RATING, CONCRETE COLLAR IS REQUIRED. CONCRETE COLLAR WITH QUANTITY (2) #4 REINFORCING BARS TO BE PROVIDED BY CONTRACTOR. 7) ALL STORMFILTERS REQUIRE REGULAR MAINTENANCE. REFER TO OPERATION AND MAINTENANCE GUIDELINES POR MORE INFORMATION. INLET GRATE I -CARTRIDGE CATCfBASIN STORMFIL.TER DATA STRUCTURE ID XXX WATER QUALITY FLOW RATE (cfs) X.XX PEAK FLOW RATE (< I cfs) X.XX RETURN PERIOD OF PEAK FLOW (rs) XXX CARTRIDGE FLOW RATE { i 5 OR 7.5 m) XX MEDIA TYPE (CSF, PERLITE, ZPG) XXXXX RIM ELEVATION XXX.XX' PIPE DATA: I.E. DIAMETER INLET STUB XXX.XX' XX" OUTLET STUB XXX.XX' XX" CONFIGURATION OUTLL-T~ pUTLET '--cr-'--=' '-='~~ INLET INLET SLOPED LID YES\NO SOLID COVER YES\NO NOTES/SPECIAL REQUIREMENT5: ACCESS COVER • y•. a ~ A9 9 ~ q • • 4. •~ 9' 9 ' ~ 9 9 . r4 ~. 9 4 . ;~ ' (j I •; INSIDE RIM .'o: IUI a qq •a . A V ,~ _ . A .q. p. ,. •,Q d 9' .. V q • 9 q "d • q 9 • 4 q. A. A. a. 2'-4" 2'-4° INSIDE RIM INSIDE RIM TIIESTORMWA7EKMANAGEPAENT 4'-8 3/4" StormFdker® OUTSIDE RIM U.S. PATENT No. 5,322,629, 1-CARTRIDGE CATCHBASIN -TOP VIEW 1 Na. 6,609,Ok8, No. 5,62,576, q AND OTt1EP U.S. AND FOREIGN X2006 CONTECH Stormwater Solutions 3 PATENTS PENDING A~_ ~ITC'AIJ® STEEL CATCHBASIN STORMFILTER DRAWINt STORNNVATER TOP VIEW, NOTES AND DATA 3 SOLUTIONS~~ STANDARD DETAIL - 1 CARTRIDGE UNIT 3/3 COnteChstoflTlw2feGC.Om DATE: 11/01/05 SCALE:NONE FILE NAME:CBSF1S-DTL DRAWN:MJW CHECKED:ARG ~~ ~ V ~~ii, tom. ~% ~ ®° G®®ftiS ~d®9JG®9 ®~d®®@J® S®fVC. • Size and Cost Estimate Prepared by Kathryn Thomason on December 9, 2010 America's Credit Union -Stormwater Treatment System Yelm, WA Information provided: • Total contributing area = 0.021 acre • Impervious area = 0.021 acre • Water quality flow, QWq = 0.0036 cfs • Peak hydraulic flow rate, Qpeak = 0.023 cfs • Presiding agency =City of Yelm, WA Assumptions: • Media = ZPG cartridges • Cartridge Height = 18" • Cartridge Flow Rate = 7.5 gpm • Drop required from RIM to outlet = 2.3' minimum Size and cost estimates: The StormFilter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate associated with the design storm. The water quality flow rate was calculated by using WWHM and provided to CONTECH Stormwater Solutions Inc. The StormFilter for this site was sized based on treatment flow rate of 0.0036 cfs. To accommodate this treatment flow rate, CONTECH Stormwater Solutions recommends using a steel single-cartridge CatchBasin StormFilter (see attached detail}. The estimated cost of this size system is $5,400, complete and delivered to the jobsite. The contractor is responsible for setting the CatchBasin StormFilter and all external plumbing. The steel CatchBasin StormFilter has an internal bypass capacify of 1.0 cfs, which does not exceed the peak flows from this site. ©2008 CONTECH Construction Products Inc. 11835 NE Glenn ceding Dr., Portland OR 97220 Page 1 of 1 www.contech-cpi.com Toll-free: 800.548.4667 Fax: 800.561.1271 TS-P026 ~~~~ APPENDIX E Conveyance Calculations SEi America's Credit Union -Conveyance Calculations for 12" Pipe Project Information Project America's Credit Union Project # 10104.10 Pipe 12" ADS N-12 Input Data Mannings Coefficient 0.012 Channel Cross-section Circular Channel Slope 0.005000 ft/ft Depth 1 ft Diameter 12 in Results Discharge 2.73 cfs Flow Area 0.79 ft2 Wetted Perimeter 3,14 ft Hydraulic Radius 0.25 ft Top Width 6.32E-0$ ft Critical Depth 0,71 ft Percent Full 100 Critical Slope 0.009404 ft/ft Velocity 3.48 ft/sec Velocity Head 0.19 ft Specific Energy 1.19 ft Froude Number 1.74E-04 Maximum Discharge 2.94 cfs Full Flow Capacity 2.73 cfs > 0.403 cfs OK Flaw is subcritical Equafions obtained from: Mays, Stormwafer Collection Systems Design Handbook (2041), Chapter 3 Lindeburg, Civil Engineering Reference Manua! (2006), Chapter 18 The critical 12" pipe is the pipe upstream of the biofiltration Swale, which is sloped at 0.5%. Fora 12" pipe sloped at 0.50% the full flow capacity is calculated to be 2.73 cfs. The 100-yr flow rate for the critical pipe is 0.403 cfs (see Appendix D). This flow rate is well below the full flow capacity. ~` America's Credit Union -Conveyance Calculations for 8" Pipe Projecf Information Project America's Credit Union Project # 10104.10 Pipe 8" ADS N-12 Input Dafa Mannings Coefficient 0.012 Channel Cross-section Circular Channel Slope 0.005000 ft/ft Depth 0.666667 ft Diameter 8 in Results Discharge 0.92 cfs Flow Area 0.35 ft2 Wetted Perimeter 2.09 ft Hydraulic Radius 0.17 ft Top Width 4.21 E-08 ft Critical Depth 0.46 ft Percent Full 100 Critical Slope 0.010401 ft/ft Velocity 2.66 ft/sec Velocity Head 0.'11 ft Specific Energy 0.78 ft Froude Number 1.33E-04 Maximum Discharge 1.00 cfs Flow is subcritical Full Flow Capacity 0.92 cfs > 0.111 cfs AK 1,~. Equations obtained from: Mays, Stormwater Collection Systems Design Handbook (2001), Chapter 3 Lindeburg, Civil Engineering Reference Manual (2006), Chapter 19 All 8" pipes are sloped at a minimum of 0.50% or greater. For an 8" pipe sloped at 0.50% the full flow capacity is calculated to be 0.92 cfs. The highest flow rate in the 8" pipes occurs in the lateral that connects the roof drain system for the building to the storm drain system. The 100-yr flow rate for this pipe is 0.111 cfs (see the WWHM3 repor# on the following pages in this Appendix). This flow rate is well below the capacity calculated for an 8" pipe sloped at 0.50%. Note that this is a conservative comparison since the pipe is sloped at 9.72% and its capacity is actually greater. ~~~ Western Washington Hydrology Model PROJECT REPORT Project Name: SBl-roof Site Address: 415 E Yelm Ave Gity Yelm Report Date 12/9/2010 Gage Lake Lawrence Data Start 1955/10/01 Data End 2008/09/30 Precip Scale: 0.86 WWHM3 Version: PREDEVELOPED LAND USE Name SBl-PREDEV Bypass: No GroundWater: No Pervious Land Use Acres A B, Forest, Flat .105 Impervious Land Use Acres Element Flows To: Surface Interflow Groundwater Name SB1-DEV Bypass: No GroundWater: No Pervious Land Use Acres Impervious Land Use Acres ROOF TOPS FLAT 0.103 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE ~-3 ANALYSIS RESULTS Flow Frequency Return Periods for Predeveloped. POC ##1 Return Period Flow(cfs) 2 year 0.000156 5 year 0.000433 I 10 year 0.000798 25 year 0.001631 50 year 0.002678 100 year 0.004285 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.042952 5 year 0.058353 10 year 0.069652 25 year 0.085231 50 year 0.097818 100 year 0.111274 E Sub basin 1 goof} 10~-yr flow rate This program and accompanying documentation is provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by the user. Clear Creek Solutions and the Washington State Department of Ecology disclaims all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. Tn no event shall Clear Creek Solutions and/or the Washington State Department of Ecology be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss o.f business information, bu:>iress interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions or the Washington State Department of Ecology has been advised of the possibility of such damages, E-~ APPENDIX F Operations and Maintenance Manual Ski OPERATIONS and MAINTENANCE Manual FOR AMERICA'S CREDIT UNION YELM BRANCH YELM9 V6~ASHING-TON Dec~rnbe~ 2010 Prepared For: America's Credit Union P.O. Box 33338 Fort Lewis, VGA 98433 Prepared By: Timothy D, Holderman, P.E., Principal REPORT #10104.10 ~C ATTACHMENT A Maintenance and Operations Information Project Information Address: 415 E Yelm Ave, Yelm, WA 98567 Tax Parcel Numbers: 22719342800 Ownership/Maintenance: America's Credit Union P.O. Box 33338 Fort Lewis, WA 98433 On-Site Storm System Main: N/A System Descripti®n stormwater drainage facilities for the proposed improvements collect and convey stormwater runoff to two infiltration systems located in the northeast and south west corners of the subject site. All stormwater entering the infiltration systems wi{I be treated via a biofiltration swale and a stormfilter located in the southwest and northeast portions of the site, respectively. A copy of this Maintenance and Operations Manual will be located onsite and be made available for inspection by the City of Yelm. Maintenance Practices The internal storm drainage system maintenance will solely be placed upon the owner. It is the responsibility of the owner to maintain accurate records of the inspections and maintenance actions taken. The attached maintenance checklist should be utilized as a minimum guide to maintenance procedures onsite. ~~ cl Instructions for Use of Maintenance Checklists The following pages contain maintenance needs for the components that are part of your drainage system. Let the City know if there are some components missing from these pages. Ignore the requirements that do not apply to your system. You should plan to complete a checklist for all system components on the following schedule: a. Monthly from November through April. b. Once in late summer (preferable September) c. After any major storm (use 1-inch in 24-hours as a guideline), items marked "S" only. Using photocopies of these pages, check off the problems you looked for each time you did an inspection. Add comments on problems found and actions taken. Keep these "checked" sheets in your files. Some items do not need to be looked at every time an inspection is done. Use the suggested frequency at the left of each itern as a guideline for your inspection. Maintenance of alternative pavement systems Alternative pavement systems may be used to reduce the overall imperious coverage. The following maintenance requirements are taken from the 200j Stormwater Management Manual fog WesteNn Washington (hereafter referred to as the 200.5 DOE Manual). • 1=ollow manufacturer's suggestions for maintenance. • Inspect project upon completion to correct accumulation of fine material. Conduct periodic visual inspections to determine if surfaces are clogged. • Sweep non-planted surfaces with ahigh-efficiency sweeper twice per year, one in autumn and one in early spring. Sweeping frequency can be reduced if Maintenance records shall be retained and provided to the City upon request. Maintenance Checklists See the following pages for these attachments. ~~ C2 REQUIRED ACTIONS: The following actions shall be taken to ensure that pollution generated on site shall be minimized (not all actions may apply to your site): 1. Warning signs (e.g., "Dump No Waste-Drains to Stream") shall be painted or embossed on or adjacent to all storm drain inlets. They shall be repainted as needed. Contact the City of Yelm regarding availability of stenciling supplies. 2. Paved Parking lots shall be swept when necessary to remove debris and, at a minimum, twice a year. Use of newer model high-velocity vacuum sweepers is recommended, as they are more effective in removing the more harmful smaller particles from paved surfaces. 3. Sediment removed shall be disposed of in a proper manner. Contact the City of Yelm for instruction prior to completing this task. 4. No activities shall be conducted on sites that are likely to result in short-term, high-concentration discharge of pollution to the stormwater system. Such activities may include, but are not limited to; vehicle washing, vehicle maintenance, and cleaning of equipment used in the periodic maintenance of buildings and paved surfaces. ~~ c~ Maintenance Checklist for Catch Basins, Inlets and Inserts Drainage Frequency System ~ Problem Conditions To Check For Conditions That Should Exist Feature Trash, debris, Trash or debris in front of the No trash or debris located ~ M, S General and sediment in catch basin opening is blocking immediately in front of the catch or on basin the capacity by more than 10%. basin opening. Grate is kept clean and allows water to enter. Sediment or debris (in the basin) that exceeds 1/3 the depth from the bottom of basin to invert of the lowest pipe into or out of the No sediment or debris in the catch A basin. basin. Catch basin is dug out and Also check insert for gravel and clean. remove if gravel exceeds bottom 1/3 insert. M, S Trash or debris in any inlet or pipe blocking more than 1/3 of its Inlet and outlet pipes free of trash height. or debris. Structural Corner of frame extends more A damage to frame than'/ inch past curb face into Frame is even with curb. and/or top slab street (if applicable). Top slab has holes larger than 2 A square inches or cracks wider ' Top slab is free of holes and than /a inch (intent is to make cracks sure all material is running into . catch basin). Frame nat sitting flush on the top A slab, i.e., separation of more than '/< inch of the frame from the top Frame is sitting flush on top slab. slab. _ _ Cracks wider than '/z inch and longer than 3 feet, any evidence Basin replaced or repaired to A Cracks in basin of soil particles entering the catch design standards. Contact a walls/bottom basin through cracks, or professional engineer for maintenance person judges that evaluation. structure is unsound. Cracks wider than '/z inch and longer than 1 foot at the joint of No cracks more than '/4 inches A any inlet/outlet pipe or any wide at the oint of inlet/outlet evidence of soil particles entering pipe. Contact a professional the catch basin through cracks. engineer far evaluation. A Settlement! Basin has settled more than 1 Basin replaced or repaired to desi n standards. Contact a g misali nment g inch or has rotated more than 2 professional engineer for inches out of alignment. evaluation. Presence of chemicals such as M, S Fire hazard or natural gas, oil, and gasoline. No color, odor, or sludge. Basin other pollution Obnoxious color, odor, nr sludge is dug out and clean. noted. Outlet pipe is Vegetation or roots growing in M, S clogged with inlet outlet pipe joints that are No vegetation or root growth vegetation more than 6 inches tall and less present. than 6 inches apart. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: Key: A=Annual (March or April preferred) M= Monthly (see schedule) S= After Major Storms (use 1-inch in 24 hours as a guideline) ~~ CS Maintenance Checklist for Conveyance Systems (Pipes, Ditches, and Swales) i Drainage Frequency System ' J Problem Conditions To Check For Conditions That Should Exist Feature A Pipes Sediment & Ac0 umulated sediment that exceeds Pipe cleaned of all sediment and debris 20 /° of the diameter of the pipe. debris. A Vegetation Vegetation that reduces free movement of water through the All vegetation removed so water flows freely through pipes. pipes. Damaged Protective coating is damaged; rust A (rusted, bent or is causing more than 50% Pipe repaired or replaced. crushed) deterioration in any part of the pipe. Any dent that significantly impedes A flow (i.e., decreases the cross pipe repaired or replaced. section area of pipe by more than 20%). A Pipe has major cracks or tears pipe repaired or replaced. allowing groundwater leakage. Dumping of yard wastes such as grass clippings and branches into M S open Trash & debris basin. Unsightly accumulation if Remove trash and debris and , ditches nondegradable materials such as dispose as prescribed by the City. glass, plastic, metal, foam, and coated paper. A Sediment Accumulated sediment that exceeds Ditch cleaned of all sediment and buildup 20% of the design depth. debris so that it matches design. Vegetation (e.g., weedy shrubs or Water flows freely through ditches. A Vegetation saplings) that reduces free Grassy vegetation should be left movement of water through ditches. alone. M Erosion damage to slopes See Ponds Checklist. See Ponds Checklist. Rock lining out A of place or Maintenance person can see native Replace rocks to design standard. missing (if soil beneath the rock lining. applicable] Varies Catch basins See Catch Basins Checklist. _ See Catch Basins Checklist. M, S Swales Trash & debris See above for ditches. See above for ditches. M Sediment See above for ditches Vegetation may need to be buildup . replanted after cleaning. Aerate soils and reseed and mulch Vegetation not Grass cover is sparse and seedy or bare areas. Maintain grass height M growing or areas are overgrown with woody at a minimum of 6 inches for best overgrown vegetation. stormwater treatment. Remove woody growth, recontour and reseed as necessary. M, S Erosion damage to slopes See Ponds Checklist. See Ponds Checklist. Conversion by If possible, speak with homeowner M owner to Swale has been filled in or blocked and request that swale area be incompatible use by shed, woodpile, shrubbery, etc. restored. Contact the city to report problem if not rectified voluntaril . A survey may be needed to check Swale does not Water stands in Swale or flow grades. Grades need to be in the A drain velocity is very slow. Stagnation 5% range if possible. If grade is occurs. less than 1% underdrains may need to be installed. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: Key: A= Annual (March or April preferred) M= Monthly (see schedule) S= After Major Storms (use 1-inch in 24 hours as a guideline) ~~ C6 Maintenance Checklist for Energy Dissipators Drainage Frequency System ' J Problem Conditions To Check For Conditions That Should Exist Feature Only one layer of rock exists above A Rock Pad Missing or moved rock native soil in area 5 square feet or larger, or any exposure of native Replace rocks to design standard. soil. Rock-filled A trench for Missing or Add large rock (+30 or-30 Ib. each) discharge moved rock Trench is full of rock. so that rock is visible above edge of from pond trench. M Dispersion wiph plugged Accumulated sediment that exceeds trench sediment 20% of the design depth. pipe cleaned/flushed. M Perforations Over YZ of perforations in pipe ere Clean of replace perforated pipe plu ed plu ed with debris and sediment. . Not Visual evidence of water discharging at concentrated points Trench must be redesigned or M, S dischar in g g along trench (normal condition is a rebuilt to standard. Elevation of lip water "sheet flow" of water along trench). of trench should be the same (flat) properly Intent is to prevent erosion damage. at all points. Water flows Maintenance person observes Facility must be rebuilt or M, S out top of water flowing out during any storm redesigned to standards. Pipe is "distributor" or it is causing or appears likely to probably plugged or damaged and catch basin cause damage. needs replacement. Receiving Water in receiving area is causing Stabilize slope with grass or other M, S area over- or has potential of causing vegetation, or rock if condition is saturated landslide. severe. Contact a professional engineer for evaluation. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: Key: A= Annual (March or April preferred) M= Monthly (see schedule) S= After Major Storms (use 1-inch in 24 hours as a guideline) ~8 ~~ Maintenance Checklist for Grounds (Landscaping) Drainage Frequency System ~ Problem Conditions To Check For Conditions That Should Exist Feature M General weeds weeds growing more than 20% of the landscaped area (trees and weeds present in less than 5% of (nonpoisonous) shrubs only). the landscaped area. M Insect hazard Any presence of poison ivy or other poisonous vegetation or No poisonous vegetation or insect insect nests. nests present in landscaped area. M, S Trash or litter See Ponds Checklist. See Ponds Checklist. Causes of erosion are identified M S Erosion of Noticeable rifts are seen in and steps taken to slow , ground surface landscaped areas. down/separate out the water. Eroded areas are filled, contoured, and seeded. Trees & Limbs or parts of trees or shrubs that are split or broken which Trim trees/shrubs to restore A Shrubs Damage affect more than 25% of the total shape. Replace trees/shrubs with foliage of the tree or shrub. severe damage. M Trees or shrubs that have been Replant tree, inspecting for injury blown down or knocked over to stem or roots. Replace if . severely damaged. Trees or shrubs, which are not place stakes and rubber coated A adequately supported or are ties around young trees/shrubs for leaning over, causing exposure of support. the roots. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: Key: ,4= Annual (March or April preferred) M= Montrtly (see schedule) S= After Major Storms (use 1-inch in 24 hours as a guideline) ~~ cs ~-,~ i~~~~~r~u s`T~RM1~~.`l~~ ~---~ sv~~non~~_~ StormFilter Inspection and Maintenance Procedures T Is!' SScrmc~.a'ar !,4erig!*mrl# ~t~f~'l~l~~~f~ ~~ Maintenance Guidelines The primary purpose of the Stormwater Management StormFilter® is to filter out and prevent pollutants from entering our waterways. Like any effective filtration system, periodically these pollutants must be removed to restore the StormFilter to its full efficiency and effectiveness. Maintenance requirements and frequency are dependent on the pollutant load characteristics of each site. Maintenance activities may be required in the event of a chemical spill or due to excessive sediment loading from site erosion or extreme storms. It is a good practice to inspect the system after major storm events. Maintenance Procedures Although there are likely many effective maintenance options, we believe the following procedure is efficient and can be implemented using common equipment and existing maintenance protocols. A two step procedure is recommended as follows: 1. Inspection Inspection of the vault interior to determine the need for maintenance. 2. Maintenance Cartridge replacement Sediment removal Inspection and Maintenance Timing At least one scheduled inspection should take place per year with maintenance following as warranted. First, an inspection should be done before the winter season. During the inspection the need for maintenance should be determined and, if disposal during maintenance will be required, samples of the accumulated sediments and media should be obtained. z In addition to these two activities, it is important to check the condition of the StormFilter unit after major storms for potential damage caused by high flows and for high sediment accumulation that may be caused by localized erosion in the drainage area. It may be necessary to adjust the inspection/ maintenance schedule depending on the actual operating conditions encountered by the system. In general, inspection activities can be conducted at any time, and maintenance should occur, if warranted, in late summer to early fall when flows into the system are not likely to be present. Maintenance Frequency The primary factor controlling timing of maintenance of the StormFilter is sediment loading. A properly functioning system will remove solids from water by trapping particulates in the porous structure of the filter media inside the cartridges. The flow through the system will naturally decrease as more and more particulates are trapped. Eventually the flow through the cartridges will be low enough to require replacement. It may be possible to extend the usable span of the cartridges by removing sediment from upstream trapping devices on aroutine as-needed basis in order to prevent material from being re-suspended and discharged to the StormFilter treatment system. Site conditions greatly influence maintenance requirements. StormFilter units located in areas with erosion or active construction may need to be inspected and maintained more often than those with fully stabilized surface conditions. The maintenance frequency may be adjusted as additional monitoring information becomes available during the inspection program. Areas that develop known problems should be inspected more frequently than areas that demonstrate no problems, particularly after major storms. Ultimately, inspection and maintenance activities should be scheduled based on the historic records and characteristics of an individual StormFilter system or site. It is recommended that the site owner develop a database to properly manage StormFilter inspection and maintenance programs. Prior to the development of the maintenance database, the following maintenance frequencies should be followed: Inspection One time per year After major storms Maintenance As needed, based on results of inspection (The average maintenance lifecycle is approximately 1-3 years) Per Regulatory requirement In the event of a chemical spill Frequencies should be updated as required. The recommended initial frequency for inspection is one time per year. StormFilter units should be inspected after major storms. ~6~ Second, if warranted, a maintenance (replacement of the filter cartridges and removal of accumulated sediments) should be performed during periods of dry weather. Sediment removal and cartridge replacement on an as needed basis is recommended unless site conditions warrant. Once an understanding of site characteristics has been established, maintenance may not be needed for one to three years, but inspection is warranted and recommended annually. Inspection Procedures The primary goal of an inspection is to assess the condition of the cartridges relative to the level of visual sediment loading as it relates to decreased treatment capacity. It may be desirable to conduct this inspection during a storm to observe the relative flow through the filter cartridges. If the submerged cartridges are severely plugged, then typically large amounts of sediments will be present and very little flow will be discharged from the drainage pipes. If this is the case, then maintenance is warranted and the cartridges need to be replaced. Warning: In the case of a spill, the worker should abort inspection activities until the proper guidance is obtained. Notify the local hazard control agency and CONTECH Stormwater Solutions immediately. To conduct an inspection: Important: Inspection should be performed by a person who is familiar with the operation and configuration of the StormFilter treatment unit. 3.Open the access portals to the vault and allow the system vent. 4. Without entering the vault, visually inspect the inside of the unit, and note accumulations of liquids and solids. 5. Be sure to record the level of sediment build-up on the floor of the vault, in the forebay, and on top of the cartridges. If flow is occurring, note the flow of water per drainage pipe. Record all observations. Digital pictures are valuable for historical documentation. 6. Close and fasten the access portals. 7. Remove safety equipment. 8. If appropriate, make notes about the local drainage area relative to ongoing construction, erosion problems, or high loading of other materials to the system. 9. Discuss conditions that suggest maintenance and make decision as to weather or not maintenance is needed. Maintenance Decision Tree The need for maintenance is typically based on results of the inspection. The following Maintenance Decision Tree should be used as a general guide. (Other factors, such as Regulatory Requirements, may need to be considered) 2. Sediment loading on top of the cartridge. a. If >1/4" of accumulation, maintenance is required. 3. Submerged cartridges. a. If >4" of static water in the cartridge bay for more that 24 hours after end of rain event, maintenance is required. 4. Plugged media. a. If pore space between media granules is absent, maintenance is required. 5. Bypass condition. a. If inspection is conducted during an average rain fall event and StormFilter remains in bypass condition (water over the internal outlet baffle wall or submerged cartridges), maintenance is required. 6. Hazardous material release. a. If hazardous material release (automotive fluids or other) is reported, maintenance is required. 7. Pronounced scum line. a. If pronounced scum line (say ? 1/4" thick) is present above top cap, maintenance is required. 8. Calendar Lifecycle. a. If system has not been maintained for 3 years maintenance is required. ~ ~~ 1. Sediment loading on the vault floor. a. If >4" of accumulated sediment, maintenance is required. 1. If applicable, set up safety equipment to protect and notify surrounding vehicle and pedestrian traffic. 2. Visually inspect the external condition of the unit and take notes concerning defects/problems. Assumptions • No rainfall for 24 hours or more • No upstream detention (at least not draining into StormFilter) • Structure is online • Outlet pipe is clear of obstruction • Construction bypass is plugged Maintenance Depending on the configuration of the particular system, maintenance personnel will be required to enter the vault to perform the maintenance. Important: If vault entry is required, OSHA rules for confined space entry must be followed. Filter cartridge replacement should occur during dry weather. It may be necessary to plug the filter inlet pipe if base flows is occurring. Replacement cartridges can be delivered to the site or customers facility. Information concerning how to obtain the replacement cartridges is available from CONTECH Stormwater Solutions. Warning: In the case of a spill, the maintenance personnel should abort maintenance activities until the proper guidance is obtained. Notify the local hazard control agency and CONTECH Stormwater Solutions immediately. To conduct cartridge replacement and sediment removal maintenance: 1. If applicable, set up safety equipment to protect maintenance personnel and pedestrians from site hazards. 2. Visually inspect the external condition of the unit and take notes concerning defects/problems. 3. Open the doors (access portals) to the vault and allow the system to vent. 4. Without entering the vault, give the inside of the unit, including components, a general condition inspection. 5. Make notes about the external and internal condition of the vault. Give particular attention to recording the level of sediment build-upon the floor of the vault, in the forebay, and on top of the internal components. 6. Using appropriate equipment offload the replacement cartridges (up to 150 lbs. each} and set aside. 7. Remove used cartridges from the vault using one of the following methods: Method 1: A. This activity will require that maintenance personnel enter the vault to remove the cartridges from the under drain manifold and place them under the vault opening for lifting (removal). Unscrew (counterclockwise rotations) each filter cartridge from the underdrain connector. Roll the loose cartridge, on edge, to a convenient spot beneath the vault access. Using appropriate hoisting equipment, attach a cable from the boom, crane, or tripod to the loose cartridge. Contact CONTECH Stormwater Solutions for suggested attachment devices. 4 4 _m ~~ ~~ Important: Note that cartridges containing leaf media (CSF) do not require unscrewing from their connectors. Take care not to damage the manifold connectors. This connector should remain installed in the manifold and could be capped during the maintenance activity to prevent sediments from entering the underdrain manifold. B. Remove the used cartridges (up to 250 lbs. each) from the vault. Important: Care must be used to avoid damaging the cartridges during removal and installation. The cost of repairing components damaged during maintenance will be the responsibility of the owner unless CONTECH Stormwater Solutions performs the maintenance activities and damage is not related to discharges to the system. C. Set the used cartridge aside or load onto the hauling truck. D. Continue steps a through c until all cartridges have been removed. Method 2: A. Enter the vault using appropriate confined space protocols. B. Unscrew the cartridge cap. C. Remove the cartridge hood screws (3) hood and float. D. At location under structure access, tip the cartridge on its side. Ft3 Important: Note that cartridges containing media other than the leaf media require unscrewing from their threaded connectcrs. Take care not to damage the manifold connectors. This connector should remain installed in the manifold and capped if necessary. D. Empty the cartridge onto the vault floor. Reassemble the empty cartridge. E. Set the empty, used cartridge aside or load onto the hauling truck. F Continue steps a through e until all cartridges have been removed. 8. Remove accumulated sediment from the floor of the vault and from the forebay. This can most effectively be accomplished by use of a vacuum truck. 9. Once the sediments are removed, assess the condition of the vault and the condition of the connectors. The connectors are short sections of 2-inch schedule 40 PVC, or threaded schedule 80 PVC that should protrude about 1"above the floor of the vault. Lightly wash down the vault interior. a. If desired, apply a light coating of FDA approved silicon tube to the cutside of the exposed portion of the connectors. This ensures a watertight connection between the cartridge and the drainage pipe. b. Replace any damaged connectors. 10. Using the vacuum truck boom, crane, or tripod, lower and install the new cartridges. Once again, take care not to damage connections. 11. Close and fasten the door. 12. Remove safety equipment. 13. Finally, dispose of the accumulated materials in accordance with applicable regulations. Make arrangements to return the used em cartridges to CONTECH Stormwater Solutions. .~:4:~. F i~ Related Maintenance Activities - Performed on an as-needed basis StormFilter units are often just one of many structures in a more comprehensive stormwater drainage and treatment system. In order for maintenance of the StormFilter to be successful, it is imperative that all other components be properly maintained The maintenance/repair of upstream facilities should be carried out prior to StormFilter maintenance activities. In addition to considering upstream facilities, it is also important to correct any problems identified in the drainage area. Drainage area concerns may include: erosion problems, heavy oil loading, and discharges of inappropriate materials. ~~t~ APER~LED Material Disposal The accumulated sediment found in stormwater treatment and conveyance systems must be handled and disposed of in accordance with regulatory protocols. It is possible for sediments to contain measurable concentrations of heavy metals and organic chemicals (such as pesticides and petroleum products). Areas with the greatest potential for high pollutant loading include industrial areas and heavily traveled roads. Sediments and water must be disposed of in accordance with all applicable waste disposal regulations. When scheduling maintenance, consideration must be made for the disposal of solid and liquid wastes. This typically requires coordination with a local landfill for solid waste disposal. For liquid waste disposal a number of options are available including a municipal vacuum truck decant facility, local waste water treatment plant or on-site treatment and discharge. sre~c~~~crex _-_.__ _ 800.925.5240 contechstormwater.com Support • Drawings and specifications are available at contechstormwater.com. • Site-specific design support is available from our engineers. ©2007 CONTECH stormwater Solutions CONTECH Construction Products Inc. provides site solutions for the civil engineering industry. CONTECH's portfolio includes bridges, drainage, sanitary sewer, stormwater and earth stabilization products. For information on other CONTECH division offerings, visit contech-cpi.com or call 800.338.1122 Nothing in this catalog should be construed as an expressed warranty or an implied warranty of merchantability or fitness for any particular purpose. See the CONTECH standard quotation or acknowledgement for applicable warranties and other terms and conditions of sale. ~l5 ! Date: Personnel: Location: System Size: System Type: Vault ^ Cast-In-Place ^j Linear Catch Basin ~ Manhole ^ Other ^ Date: Sediment Thickness in Forebay: I ~ Sediment Depth on Vault Floor: Structural ~amane• Estimated Flow from Drainage Pipes (if available): Cartridges Submerged: Yes ^ No ^ Depth of Standing Water: StormFilter Maintenance Activities (check off if done and give description) ^ Trash and Debris Removal: ^ Minor Structural Repairs: ~ Orainanr Araa RPnnrh Excessive Oil Loading: Yes ^ No ^ Source: Sediment Accumulation on Pavement: Yes ^ No ^ Source: Erosion of Landscaped Areas: Yes ^ No ^ Source: Items Needing l=urther Work: Owners should contact the local public works department and inquire about how the department disposes of their street waste residuals. Other Comments: ~~ Review the condition reports from the previous inspection visits. Date: Personnel: Location: System Size: _ System Type: Vault ^ Cast-In-Place ^ List Safety Procedures and Equipment Used: System Observations Months in Service: Oil in Forebay: Sediment Depth in Forebay: Sediment Depth on Vault Floor: A Structural Damage: Drainage Area Report Excessive Oil Loading: Sediment Accumulation on Pavement Erosion of Landscaped Areas: Yes ^ ado ^ Source: Yes ^ No ^ Source: Yes ^ No [_] Source: Storm Filter Cartridge Replacement Maintenance Activities Remove Trash and Debris: Yes ^ No ^ Details: Replace Cartridges: Yes ^ No ^ Details: Sediment Removed: Yes ^ No ^ Details: Quantity of Sediment Removed (estimate?): Minor Structural Repairs: Yes ^ No ^ Details: Residuals (debris, sediment) Disposal Methods: Notes: Linear Catch Basin ^ Manhole ^ Other ^ Yes ^ No ^ ~~~ APPENDIX G Stormwater Pollution Prevention Plan (SWPPP) SEI Construction Stormwater Pollution Prevention Plan Checklist Project Name: America's Credit Union Yelm Branch Address: 415 E Yelm Ave, Yelm WA, 9867 Parcel No.: 22719342800 Section: 19 Township: 17 N Range: City Reference/Permit.: Review Date: On-Site Inspection Review Date: Construction SWPPP Reviewer: Section I -Construction SWPPP Narrative 1. Project Description This report accompanies the civil engineering construction plans for the the America's Credit Union Yelm Branch project. The project is located at 415 E Yelm Ave, Yelm WA, 98567. The proposed project consists of a 4,380 square foot one-story credit union/coffee housel building with a foot print area of approximately 0.101 acres and a roof area of 0.123 acres. The project site is 0.782 acres with approximately 0.391 acres of cement concrete sidewalks, asphalt pavement parking areas, and drive aisles. Approximately 0.268 acres will be landscaping. Erosion Control Specialist An Erosion Control Specialist shall be identified to oversee the improvements during construction and shall be identified below prior to issuance of the construction permit. Erosion Control Specialist: Telephone Number (24-hour): Alternate Phone Number: 02 E G1 Existing Site Conditions A. Description of the Existing Topography The project parcel is bordered to the north by Yelm Ave East (SR 507) and to the east, west, and south by residential properties. The majority of the site is relatively flat (slopes of <1%). The southwest corner of the site slopes 2% to 3%. An existing residence with detached garage is located in the north and central portions of the site. An abandoned shed is located in the south portion of the site. B. Description Of The Existing Vegetation Vegetation ir. the north and central portions of the site consists of lawn grass, ornamental trees and shrubs, and fruit trees. Conifer trees are along the west boundary of the site and Lombardy Poplars are located ire the south portion of the site. C. Description of the Existing Drainage Due to the flat topography of the site, the majority of the runoff infiltrates onsite, with a small portion of the runoff sheet flowing to the southwest corner. 3. Adjacent Areas A, Description Of Adjacent Areas Which May Be Affected By Site Disturbance 1. Streams: There are no streams adjacent to the property. 2. Lakes: There are no lakes adjacent to the property. 3, Wetlands: There are no wetlands adjacent to the property. 4. Residential Areas: The site is bordered by residential areas to the east, west, and south. These adjacent areas will not be adversely G2 affected by the proposed project. TESC measures such as silt fencing and CB inlet protection will be implemented to minimize impacts during construction. 5. Roads: The site is fronted to the north by Yelm Ave East (SR 507). Access to the site during construction will be accomplished via a stabilized construction entrance off of Yelm Ave East in the northwestern corner of the project site where an existing driveway is currently located. TESC measures such as a stabilized construction entrance, CB inlet protection and street sweeping will be implemented to limit sediment tracking onto Yelm Ave East. (See page G7 for BMPs) 6. Ditches/Pipes/Culverts: The existing conveyance system along Yelm Ave East will be protected using CB inlet protection. B. Description Of The Downstream Drainage Path Leading From The Site To The Receiving Body Of Water (minimum distance of/4 mile) All.stormwater runoff will be captured and infiltrated onsite via infiltration trenches. 4. Critical Areas There are no known critical areas onsite or adjacent to the site. 5. Soils See Appendix `A' for Soils Descriptions and Appendix `B' for Geotechnical Report prepared by E3RA, Inc. G3 6. Erosion Problem Areas A. Description Of Potential Erosion Problems On Site If all erosion control measures outlined on the TESL Plan (see page G7) are followed, no erosion control problems are foreseen. Erosion control measures will include, but are not limited to, silt fencing, stabilized construction entrance, CB inlet protection, hydroseeding, other appropriate BMP needed per City of Yelm standards to ensure adjacent properties and public right-of--way is protected. (See page G7 for BMPs) 7. Construction Stormwater Pollution Prevention Elements A. Describe flow Each Of The Construction Stormwater Pollution Prevention Elements Has Been Addressed Through The Construction SWPPP Element #1: Clearing limits will be marked onsite by a Licensed Land Surveyor and on the plans by the Project's Design Engineer. Element #2: A standard construction entrance will be placed onsite before any grading occurs. (See page G7 - TESC plan sheet) Element #3: Flow control not required. Element #4: The following measures will be taken to control sediment: 1. Silt Fencing 2. Stabilized Construction Entrance 3. CB Inlet Protection Element #5: Any areas that would require soil stabilization will have proposed pavement, building structure, or landscaping. Element #6: Slope protection and stabilization is not required due to the relatively flat nature of the site. Element #7: All applicable storm drain inlets (both existing and proposed) will be G4 protected using CB Inlet Protection. Element #8: There are no channels onsite to protect. Element #9: All pollution control will be handled and disposed of so that stormwater is not contaminated. For construction pollution, the Source control BMPs listed in Volume IV of the 200 Stormwater Management Manual for Western Washington will be utilized. (See page G7 for BMPs) Element #10: Dewatering is not anticipated to be required onsite. Element #11: All erosion control measures will be inspected, cleaned and maintained as noted in the Erosion Control Plan and BMPs. Element #12: The project will be constructed in one phase and will be constructed outside the dates of Seasonal Work Limitations to minimize sediment transportation. All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function as per the 2005 Stormwater A~lanagement Manual for Western Washington. 8. Construction Phasing A. Construction Sequence 1. Stake and/or flag limits of clearing. 2. Schedule and attend pre-construction meeting with the City of Yelm. An erosion control lead person's name and phone number shall be designated and provided to the city at this meeting. 3. Install Perimeter Protection (silt fence) and construction fence G5 ~ ~ ~ ~ y ~ ~ ~ O ~ .~ O v ~ O. ~ ~ ~ .-o ~ y N ~ .Q" ~ .~ ~ ~ N 'n n m ~ ¢, G _ i1, ^ ., ~ ~ 6' C U ~' - f ~ c6 O ~ .~ ~ ,~ N ~ ~ ctl ' bU N ~' ~ ~' ' J R. 3 n ~ ~ ~ 'O v, ~ ~ O ~ U O ~ Q ~ ~ c U , C y ~ ~ N G "~ ~ P. 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