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07-0135 Storm Drainage Rpt 031808 001Storm Drainage Report FOR Today's Dental 502 E Yelm Ave Yelm, WA 98597 March 14, 2008 Proponent: Judd and Sarah Sherman (360)458-1976 Prepared by: Lucas Johnson, E.I.T. Reviewed by: Justin Goroch, P.E. BCRA 2106 Pacific Avenue, Suite 300 Tacoma, WA 98402 (253)627-4367 I hereby state that this Storm Report for the Today's Dental has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community for professional engineers. I understand that the City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. ~Il~loe :~ z ~ k] %CISTtiR~~(~~~ NAL E Table of Contents: 1. Project Overview ............................................................................. 1 2. Existing Conditions Summary ................................................................ 1 3. Off-Site Analysis Report ...................................................................... 2 4. Permanent Stormwater Control Plan ...................................................... 2 5. Construction Stormwater Pollution Prevention Ptan .................................... 3 6. Special Reports and Studies ................................................................. 3 7. Operation and Maintenance Manual ....................................................... 3 Appendices: Appendix A -Vicinity Map Appendix B - Sub-basin Map Appendix C - Geotechnical Report Appendix D -Storm Drainage Calculations Appendix E - Water Quality Calculations Appendix F- Operations and Maintenance Manual STORM DRAINAGE REPORT 1. Project Overview The Today's Dental project is located at the north corner of the Solberg Street NW and Yelm Avenue W intersection. The site consists of parcels 21724142300 and 217241452200, both of which are zoned C-1 Commercial. The site lies in Section 24, Township 17N, Range 1E. See Appendix A for a vicinity map. The project is comprised of a 0.57-acre site which will contain a newly constructed dental office building and parking lot. Construction will be divided into three phases as a means of maintaining building operations. The site will have ingress/egress points from Solberg Street. Site improvements include a stormwater filtration system, stormwater infiltration system, domestic water service, fire hydrants, and STEP sewer system. The stormwater improvements include a conveyance system that filters runoff and infiltrates it into the ground through an underground infiltration structure. Stormwater runoff from the parking lot will be captured and treated for water quality using StormFilter® cartridges. Building roof runoff will bypass the treatment system and will be conveyed directly to the StormTech~ chamber infiltration system. The StormTech~ system will allow the roof runoff to be infiltrated along with the treated parking lot runoff. See Appendix Bfor asub- basin map of the project site. 2. Existing Conditions Summary The current site has a dental office building on the southwesterly parcel (No. 21724142300) and a single family residence on the northeasterly parcel (No. 21724142200). The existing ground cover is a combination of lawn, landscaping, and gravel with trees sparsely located around the site perimeter. In general, the site slopes from north to south with slopes ranging from relatively flat to 4%. In the current condition, site stormwater sheet flows from north to south. Based on the soils information and the shallow site grades, it appears that the site currently infiltrates all of the onsite storm water. The Today's Dental site has an upper sod and topsoil layer that ranges from 6 inches to one foot in depth. This rests on top of a black ash layer with gravel that ranges in depth from 2.5 to 3.0 fee[. Underlying the ash layer is gravely glacial outwash with cobbles and boulders. This outwash extends to the depth explored, which was a maximum of 10 feet. No groundwater was encountered in any of the soil explorations. The soils are capable of infiltrating runoff at a high rate. The design infiltrate rate is suggested to be 10 inches/hour. See Appendix C for the geotechnical report. There have been no erosion problems associated with this site and we do not foresee any difficult site conditions. Based on the survey, there appears to be no fuel tanks or wells on the site. There are currently no known critical or sensitive areas on or near the project site. However, there is a septic tank and drain field that will require removal. It is located near the northernmost point of the southwesterly parcel. The septic system will be decommissioned per Department of Ecology requirements. 3. Off-Site Analysis Report The site is bordered [o the northwest by multi-family residences and a commercial building. Jefferson Avenue NW borders the site to the northeast, Yelm Avenue W (SR 510) borders the site to the southwest, and Solberg Street NW borders the site to the southeast. Based on soil information provided in the geotechnical report, it appears that the project area runoff infiltrates into the site soils. Since the site has such a good infiltration ability, stormwater flow management will be achieved by utilizing an underground infiltration facility. A downstream analysis is not provided in this report since infiltration will be utilized. It appears that the site does not accept any off-site runoff. Based on the survey and generally mild slopes, current runoff from adjacent sites also appears to infiltrate into the soil. 4. Permanent stormwater Control Plan Flaw Control System The site will utilize a StormTech~ chamber system to infiltrate onsite runoff. The system consists of plastic, dome-shaped, bottomless chambers that are to be backfilled with porous drain rock. Based on the geotechnical report by E3RA dated January 5, 2007, an infiltration rate of 10 in/hr is used for the design. The footprint of [he system will be approximately 11 feet wide by 61 feet long and will contain 17 chambers. See Appendix D for calculations and typical details for the system. See Appendix C for the geotechnical report. Water Quality System Runoff from the parking lot will be treated using StormFilter® cartridges manufactured by Contech stormwater Solutions. Treatment will occur upstream of the StormTechO chamber system to minimize the amount of un- treated runoff that is infiltrated into the ground. four filter cartridges will rest inside of a 72" manhole structure that is designed to completely filter the 6- month storm event. Larger storms that exceed the filtration capacity of the cartridges will bypass filtration through an overflow weir that is located inside of the manhole structure. Each filtration cartridge is 18" tall and has a maximum filtration flowrate of 15 gallons/minute. The filtration media used in the cartridges is zeolite, perlite, and granular activated carbon (ZPG). ZPG media was chosen for the Today's Dental site because it is suggested for treating sediments, oil and grease, total nutrients, complexed and soluble metals, anthropogenic organic contaminants, and ammonia. See Appendix E for the water quality calculations. Conveyance System Analysis and Design Runoff from [he parking lot is captured by a series of catch basins and conveyed to the StormFilter system for water quality treatment. The runoff is then conveyed to the StormTechO chamber system where it is infiltrated. Since roof runoff does not have to be treated for water quality, it is captured and conveyed separately from the runoff from the parking lot. It is conveyed directly to the S[ormTech~ chamber system. All conveyance systems are sized for the 100-year storm even[. Manning's Equation was used to determine the maximum flowrate that [he last pipe run in the system could tolerate (assuming uniform flow). The anticipated maximum flowrate for the 100-year event was then checked against the maximum allowable flowrate that the pipe can tolerate. The 100-year storm event flow rate is less than the maximum allowable flowrate, indicating that the pipe size chosen (8" diameter) is capable of conveying the 100-year storm even[. If the 100-year storm event occurs, it will create a flowrate that fills the pipe to a depth of 0.4 feet (approximately 59.2% full). See Appendix D for conveyance calculations. Construction Stormwater Pollution Prevention Plan The Construction Stormwater Pollution Prevention Plan (SWPPP) is a separate document. It will be submitted along with this storm drainage report. 6. Special Reports and Studies A soil analysis report was completed for the Today's Dental site by E3RA, Inc. A copy of the geotechnical report can be found in Appendix C. Operation and Maintenance Manual An operation and Maintenance Manual can be found in Appendix F. APPENDIX A VICINITY MAP J l 1 (J APPENDIX B SUB-BASIN MAP B~ 40 60 ~~ _. ,~~ -___ =9• ~o _ -__~ a~ ,= _ a~ d U .3 3 3 ^ 0 ti a U U O ~ ' 4 f _ ~ ~~ s - O 0 a - 0 V 6 ^ Ua APPENDIX C GEOTECHNICAL REPORT Eoa 44E a~ --aroma SNP. 98444 253-537-°^OG 2v3-63-5q(i1 raz E3RA January 4, 2006 706397 Yelm Dental Center. LLC X02 Yelm Avenue West Yehn, WA 9R579 Attention: Ur. Sarah Sherman Subject: Geotechnical Engiucering Report Planned Commercial Development 502 Yelm Avenue West, P/N 21 7241 423 0 0 107 Solberg Street. ['M 21 724 1 4220 0 Yelm, Washington Dear Sarah: E3RA is pleased to submit this reportdesctibing the results ofour geoteehnical engineering evaluation forthe residential development planned at 502 Yelm Ave West and 107 Solberg Street m Yelm, Washing on. This report has been prepared for the exclusive usa of Yclm Dental Center, LLC and their cousul[ants, for specific application to [iris project, in accordance with generally accepted geotechnical engineering practice. 1.0 SITE AND PROSECT DESCRIPTION The planned commercial developtnen[ is located on the corner of SR 510 and S W Solberg St in Yelm, Washhrgtoq as shown on the enclosed Location Map (Figure 1). It consists of [wo rectangular parcels that measure about 80 feet fronting SR 510 and 300 feet fronting Solberg Street. The project site is curten[ly bordered by SR 510 fo the southwest, Jefferson Ave to the northeast, and Solber St to fhe east. Surface topography is relatively level. Plans call for the removal of the existing home and dental office and construction of a new dental office, associated parking and a stoun water infiltration faciliTy. The properties will have access from Solberg St. 2.0 EXPLORATORY METHODS We explored surface and subsurface conditions at the project site on November 18, 2006. Our expbration program comprised the folbwing elements: A surface reeonnaissamce of the two parcels; Ten test pits (designated TP-I through 'LP-3), advanced across the site; One Grain Size analyses of on-site soils; Three Infiltration Tests; and January 5, 2007 TOS3971 Yelm Deota! A review of published geologic and sismologic maps and literature. ecr2rl i:~a Table 1 summerzes the approximate fimdienal locations and mmuna[iou depths oC our subsurface explorations, and Figure2 depicts [heir approximate relative locations- The following text sections describe the procedures used for excavation of test pits- TABLGI APPROXIMATE LOCATIONS AND DEPT[3S OF EXPLORATIONS Tcrminafion Depth Exploration Fnoctional Location (feet) *TP-L Southwest site 8 *TP-2 Cenhal part cast site 10 *'fP-3 Cennal site 10 * Includes infiltration test 'Cbe specific number and locations of our explorations were selected in relation to the existing site features, under the constraints of surface access, and underground utility conflicts. It should be realized that the explorations performed and utilized for this evaluation reveal subsurface conditions only at discrete locations across the project site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would no[ become evident unfit additional explorations are performed or until construction activities have begun. Ifsignificant variations are observed at that time, we may need to modify our conclusions and recommenda[ionseontained in this report to reflect the actual site conditions. 21 Tes[Pit Procedures Our exploratory test pits were excavated with a steel-tracked excavator operated by an independent firm working under subcontract to E3RA. An engineer from our firm wntinuously observed the test pit excavations, logged the subsurface conditions, and collected samples. After we logged each test pit, the excavator operator backfilled it with excavated soils and tamped the surface. The enclosed Tesk Pft Logs indicate the vertical sequence of soils and materials encountered in each test pif, based on our field classifications. Where a soil wntact was observed to be gradational or undulating, our logs indicate the average contact depth. We estimated the relative density and consistency ofthe in-situ soils by means of the excavation characteristics and the stabiliTy of the test pit sidewalk. Our logs also indicate the approximate depths of any sidewall caving or groundwate[ seepage observed in the test pits, as well as aII sample numbers and sampling locations. 2_2 Infiltration Tes[ Procedures We performed falling head infiltration tests at a dead[ oCabout 7 feet within test nits TP-1, 2, and 3. All falling head tests were performed m general accordance with the falling head Type infiltration testing procedure described in the EPA publication On-site Wastewater Treatment and Disposal System 1980, described below. .;anuary 5, 200? ERA. Inc. T06397 ! Yelm Dental A 6-inch-diameter PVC pipe was tamped 3 to 5 inches into Lhe soil oC [he upper pan of the infiltration layer, Then 2 inches of coarse, clean drain rock was placed at the bottom oCLhe pipe Lo prevent scouring. Soil was placed and tamped outside [he pipe Cor stabil izeGon and to prevent upwel I ing oftest water around the pipe. The pipe was then filled twice with I foot of water to pre-saturate the test soils. Because, in all cases, I foot of water inf Ibated the feet soils in less than ] 0 wiu ulcs, further saturation was deemed unnecessary and the intltration test proceeded- The pipe was then filled wikh 6 inches of water, and, because site soils were found to be rapidly pertneahlo, the Time required for inf lfration otthe entire 6 inch column of water was recorded. We repeated this procedure three times at each TesT location and used only the slowest ofthe3 recorded infiltration rates in our analysis. 3.0 SITI CONDITIONS The tollowing sections of text present our observations, measurements, findings, and interpretations regardhg surface, soil, groundwater, seismic, Liquefaction, and infltration conditions. 3.1 Surface Cundilioos The project site is relatively Icvel with no noticeable change in elevation. 'Lhe 502 Yelm Ave W est parcel curtently has' an existing Yelm llenlal Office and 107 Solberg Sfreef wrzently has a home on the lot.'Phe remainder ofthe sites are yard or parking. Vegetation onsite consists of grass and some small yard trees. No signs of surface flow, such as stream channels or erosional scars, were uoted during our reconnaissance. No ponds are onsite. No seeps or springs were observed. 32 Soil Conditions Our on-site explorations revealed fairly nearly mtiformnenr-surface soil wnditions. Generally, we observed an upper sod and topsoil layer that ranged in thickness from % to a bit less ihau I foot in thickness overlaying a black ash layer with gravel ranging to a depth of about 2 1/2 to 3.0 feet Underlying the ash layer, we obsen•ed, to the termination of our explorations, which reached a maximum of about 10 feet, gravely glacial outwash with cobbles and boulders. The soils appeared to become somewhat sandier and slightly less to the nor[ti and west Caving was noted at depths of about 4 1/2 W S feet in the test pits, suggesting that water will readily infiltrate at these depths due to the nature of the soils and lack of silts. 'Lhe enclosed exploration logs provide a detailed description ofthe soil strata emcounteted in our subsurface explorations. 3.2.1 Labora[orv Tes[ine Our Gmin Size Analyses of the sandy gravel in test pits TP-I, found within the zone where infitration will likely occur (7 feet below current grades) indicate that the silt wntent is in the range of5 percent The moisture content cfsop~s-within the zcna of iaffi ~atic~is abcnt; pecent as well. Wzinterpret mcstcfthe upper soils as being close to optimum moisture. The enclosed laboratory testing sheets graphically present our test results, and Table 2 summarizes these results. .ianuzry 5. 2007 ~~RA Inc. T063571 Yal;n Dental TABI.F.2 LABORATORY TEST RESULTS FOR NON-ORGAMC ON-SITI? SOILS Soil Sample and Moisture Cravcl Content Sand Content Silt/Clay Depth Content (percent) (percent) Content ~tercent) (perceo t) "fP-I, S-I, 7 feet 5.1 70 24.8 5.2 3.3 Groundwater Conditions At the tune oC our reconnaissance (November 7 8, ?006), we did not observe groundwater iu any of our explorations, which extended to depths of up [o LO feel. No significant mottling was observed. IL is not anticipated that ground water will be encountered during typical onsite conshuction activities. 3.5 Seismic Conditions Based on out analysis of subsurface exploration logs and our review of published geologic maps, we interpreT soil conditions on the site to correspond with a seismic site class S~ as defined by Table 1615.1.5 of the 2003 International IJuildfng Code (773C). According to the IBC, the site is Seismic Region 3. 3.6 Liquefaction Potenfial 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 [hat saturated, loose, fine to medium sands with a fines (silt and clay) content less than about 20 percent are most snseeptible to liquefaction. We did not observe easily liquefiable soils onsite. 3.7 Infiltrafion Conditions A storm water infiltration facility is planned for the site. In our three test pits located in the vicinity of [his faciliy, test pits TP-1, 2, and 3, we observed loose silty sandy gravel with a fines content that averaged about 5 percent. According to the U.S.D.A. Textural Triangle, our laboratory analyses ofthis soil indicate that it is a gravel, course sand type A widr an infiltration rate of Iminute/inch. 'Ihe results of our infiltration tests are presented in Table 3. Because infiltration was moderately rapid, we recorded the time necessary fora 6 inch high column of water to infiltrate completely as discussed in section 2.2 above- Based on our field testing, the Average Infilhation Rate for soils ata depth oC7 feet is 3.0 minutes per inch. After inco[porating a Factor of Safety oft, we recotmnend a Design infiltration Rate of 6 minutes per inch (10 inches per hour). TABLES FIELD INFll,TATION TEST RESULTS Test Location Depth below exisfiog grades Field Infiltration Rate for 6 Nomber inch Column (feet T-I TP-I, parking area 7 20 miN6 arches T-2 ~ TP-2, front yard of home ~ 7 ~ 20 min/6 inches T-3 TP-3, back yard of home 7 8 min/6 inches !enu2ry 3. 2L'0? T~o35,' i Yelr Distal E3RA Ina 4.0 CONCLUSIONS ANII Rf.COMMENDATIONS Plans call for the preparation of a new dental office, paved parking and inf ltration ofstonn water onstte. We offer the tolloeving conclusions and recommendations: Feasibili[v: Based on our geld explorations, research, and analyses, the proposed development appears @asible Gom a geotechnical standpoint, provided fha[ the rearmmcndatious in Section 4 and in Lhis report are followcd- Foundation Ootions' We recommend conventional spread footings supported on firmly compacted native soils_ Recommendations for spread footings are provided in Section 4. Ploorp tp ions: We recommend eithera concrete slab-on-grade orjoist-supported floors for the proposed commercial structure. Some overescavation will be necessary Cor slab-on-grade tloors. Recommendations for slabon-grade Floors are included m Section 4. Onsite lnf Itralion: Based on our onsite infiltration tests and soils analyses, we recommend at Design Infiltration Rate of 6 minutes per inch for soils in the vicinity of the planned infiltration facility. Asphalt Pavement: Structural fill subbases appear do not appear io be necessary provided that sub-grades are compacted to 95 percent maxinmm dry density. A pavement section, consisting of 2 inches of asphalt pavement over a 4 inch crushed rock base, is recorranended for the planned parking area. The following text sections of this report present our specific geotechnical conclusions and recommendations concerning sitepreparatiou, spread footings, slab-0n-grade floors, drainage, sobgade walls, and stmctwal fill. The WSDOT Standard Specifications and Standard Plans cited herein referto WSDOT publications M41-1Q Standard Spec cations for Road, Bridge, and Municipal Construction, and M21-Ol, Standard Plans for Road, Bridge, and Municipal Construction, respectively. 4.1 Site Preoarafion Preparation ofthe project site shonld involve erosion control, temporary drainage, clearing, stripping, cutting, filling, excavations, and subgrade compaction. Erosion ControC Before new construction begins, an appropriate erosion control system should be installed. This system should collect and filter all surface run offthrough either silt fencing or a series of properly placed and secured straw bales. Weanticipate asystem of berms and drainage ditches around construction areas will provide an adequate collection system. Ifsilt feneingissalected as a filter, this fencing fabric should meetthe requirements of WSDOT Standard Specification 9-33.2 "Cable 3. In addition, silt fencing should embed a minimum of 6 inches below existing grade. If straw baling is used as a filter, bales should be secured to [he ground so that [trey will notshifl under [tie 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 shifred above ground surface should be replaced or repaired as soon as they are identified. Temporary Drainaee: We recommend intercepting and diverting any potential sources of surface or near-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 January 5, 2007 E~RF~ Inc Tb6397! Yenn fJental sequence, and contractor's methods, foal decisions regarding drainage systems are best made in the Geld at the time of construction. Based on our cuncnl understanding of [he construction plans. surface earl su bsud ice conditions, we anficipate that curbs, berms, or ditches placed around the work arias will adequately intercept surizez water runoff. Gearing and S(rinnin e: after surface and near-surface water sources have been eonh'olled, the construction areas should be cleared and stripped oCall duff; and topsoil. Our explo~atiens indicate that a th ickocss of % to i foot oftopsoii will be encounterod across the site_ Alsq if should be realized that if the stripping operation proceeds' during wet weather, e generally greater stripping depth might be necessary [o remove disturbed moisture-sensifivz soils; tiwreforo, stripping is besT pcrfonned during a period of dry weather. Site Excavations: Based on our exploatio~u, we expect that site excavations will encounter loose soils that can be easily excavated by conventional earth working equipment. Dewaterine: We do not anticipate dewatering to be necessary on dais project. 'temporary Cu[ Slopes: All Temporary soil slopes associated with site cutting or excavations should be adequately ipclined to prevent sloughing and collapsa'femporary cut slopes in site soils should he no steeper Than 1% H:1 V, and should conform m WISHA regulations. subgrade Compaction: Pxposed subgrades for foo[htgs 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 [he surrounding soils. In confrest, an}' organiq soft, or pumping soils observed within a subgrade should be overexcavated attd replaced with a suitable structural fill material. Site Filling: Our conclusions regardutg the reuse of on-site soils and our comments regarding wet-weather filling are presented subsequently. Regazdless of soil type, all fill should be placed and compacted accordurg to our reeommendatimts presented in the Structured Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform densiTy of at least 95 percent (based on ASTbCi1] 55"7). On-Site Soils: We offer the following evaluation ofthese on-site soils in relation to potential use as strucmra( fill: • .Sw~ icial Sod and Toasoil: The sod and topsoil mantling the site is not suitable for use as structural fill under any circumstances, due to high organic convent. Consequently, these materials can be used only for non-s7ucmral purposes, such as in landscaping areas. • Black Ash: The black si1Ty sandy gravel that underlies the site is currently near optimum moisture content and might possibly be reused as sfruemral till, depending on conditions aY time of construction. It is more moismre sensitive then the outwash below acrd will be difficult to reuse during wet weather conditions. • Glaeia[ Outwash: The sandy gravel with cobbles and boulders that underlies the site is currently near optimum moismre content and can be reused as structural fill This soil is less moismre sensitive and can likely be reused in wet weather conditions. 4.2 Spread Footings m our opinion, conventional spread footings will provide adequate support for the proposed sfrucmre ifthe subgrades are properly prepared. We offer the following comments and recormnendations for purposes of J~nuery 5. 200' ?0&307 / 1'e'~.m Dental footing design and consh'uc[ion_ E3P.A, inc. Foo[iue Depths and, Widths; For iiest and erosion protection, the base oCali exterior lootings should bear at Ieast24 inches below adjacent outside grades. To limit post~onstruction settlements, continuous (wall) and isolated (column) footings should be at Icast 18 and 2d inches wide, respectively- Bearing subgrades and Bcadng f_r_cssures: '1'hc native aslry l aycr and glacial outwash underlying the proposed building footprint aT SUbgmde elevations will adeyuately support spread footings. [n general, before footing concrete is placed, any Localized zones oC loose soils exposed across the footing subs ales should be compacted to a tirm, unyielding condition, and any localized zones of soft, organic, ordebris-laden soils sf you Id be over-excavated and replaced with suitable structural fill. subgrade Observation: All footing subgrades should consist oCeither firm,unyielding, native soils orsuitable structural fill materials. Footings should never be cast arop loose, soft, or frozen soil, slough, debris, existing unconnolled fill, or surfaces covered by standing water. Werecommead that[he condition ofall subgrades be observed by an E3RA representative before any concrete is placed. Bearin~Pressures: fit our opinion, forstatic loading footings lha[bear on properly prepaed subgrades can be designed for the maximum allowable soil bearingpres'sures of 2500 psf. Aone-third increase in allowable soil bearing capacity may be used for short-term loads creased by seismic or wind related activities. Footing Settlements: We estimate that total post-construction settlements oP properly designed footings bearing on properly prepared subgrades will not exceed 1 inch. Differential settlements for comparably loaded elements may approach one-half ofthis value over horizontal dismnces of approximately 50 feet. Footing and Stemwall Backfitl: To provide erosion protection and lateral load resistance, we recommend that all footing excavations be backfilled on both sides of [he footings, retaining walls, and stemwalls after the concrete has cured. Either hnported s[metuca7 fill or non-organic on-site soils can be used Cor this purpose, emrtingent on suitable moisture content at [he time ofplaeement. Regardless of soil type, all footing backfill soil should be compacted to a density of at least 90 percent (based on 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 recommend using an allowable passive earth pressure of 300 psf for the granular backfill. We recomrneud an allowable base friction coefficient of 0.35 for grmmlar soils. 4.3 Slab-On-Grade Floors In our opinion, soil-supported slab-on-grade floors can be used in the proposed structure if the subgrades are properly prepared. We offer the following comments and recommendations concemingslab-on-grade floors. Floor Subbase: Structural fill subbases do not appear to be needed under soil-supported slab-on-grade floors, iC the existing native subgrade can be thoroughly compacted. If subgrade compaction is not feasible, we recommend that granular fill be placed to a depth of 12 inches below finish subgrade. Canillarv Break and Vapor Bar ~ ec To retard the upward wicking of groundwater beneath ttte floor slab in areas where moisture sensitive floor coverings will be used, such as offices, we recommend that a capillary break be placed over the subgrade. Ideally, this capillary break would consist of a 4-inch-thick layer otpea o suet or otlrer clean, unifomr, well-rounded gravel, but clean angular gravel can be used if i[ adequately prevents capillary wicking. in addition, a Layer ofplastie sheeting (such as Crossmff, V isqueen, or Moismp) should be placed over the capillary break to serve as a vapor barrier. During subsequent casting ofthe concrete slab, the contractor should exercise care to avoid puncturing this vapor ban'ier. Janu2rv o. 2007 T06397; Yelm Dental F Sni'.. li'~~. 4.4 Drainage SVStCm\ We offer the following recommendations and comments for drainage design for construction purposes'. Perimeter Drains: We recommend that the buildings be encircled with a perimeter drain sys[cm Lo wllect seepage water This drain should consist ofa 4-inch-ditune[er perforated pipewithin an envelope of pea gravel or washed rock, extending at least 6 inches on all sides of the pipe_ The grovel envelope should he wrapped with filter fabric to reduce the m igration of fines Crum the surrounding soils. Ideally, the drain invert would be installed no more than 8 inches above the base of the perimeter footings. Subtloor Drains: Because Floor subgxdes will on a granular inaieriel, we do not recommend the use of subfloor drains. Uischaree Considerations: ]Fpossiblo, all perimeterdmins should discharge ro asuitable dis'hearge location. Runoff Wafer: Roof-runoff and surface-runoff water should wo( discharge into the perimeter drain system. Instead, these sources should discharge into separate [ightline pipes and be routed away from the buildiugto a storm drain or other appropriate location. Grading and Canning: Final 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 coucrem, asphalt, orlow-permeability (silly) soils to minimize or preclude surface-water infiltration. 4_5 Asphalt Pavement Since asphaltic pavements wilt be used for the parking area and, possibly, driveways, we offer the following comments and recommendations for pavement design and construction. Suberade Preparation: All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dumptruck or heavy compactor. Anylocalized zones ofyielding subgrade disclosed during this proof-rolling operation should be over excavated to a maximum depth of l2 inches and replaced with a suitable stmctmal fill mamrial. PavementMa[erials For [he base course, we recommend using hnported crushed rock Nativematerialssholt be adequate as a subbase. 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: Minimum Thickness Pavement Course Parking Areas High Traffic and Driveway Areas Asphalt Concrete Pavement 2 inches 3 inches rn,ehed Rnrk Race 4 i~nc~s fi inrhec Granular Fill Subbase (i£needed) 12 inches 12 Compaction and Observafiom All subbase and base course material should be compacted to at least 95 percent January 5. 2007 F°RA Inc. 706397 i Yelm Dental oRhe Modified Proctor maximum dry density (ASTM D-157), and all asphalt concrete should be compaclul to at leas( 92 percent of the Rice value (ASTM D-2041). We recommend that an C7}2A representative be retained [o observe the compaction of each conrsc before any overlying layer is placed For the subbase and pavement course, compaction is best observ=ed by nicaus oC IYeyuent density testing. For the base course, methodology observations and hand-probing are more appropriate Than density testing. Pavement Life and Maintenance: No asphahic pavement is maintenane~free. The above described pavement sections present our m inimum rceommendations for an average level of performance during a 20-year design life; Thereforo, an average level of maintenance will likely be required- Furthernore,a20-year pavement life typically assumes that an overlay will be placed after about l 0 years. 1~hicker asphal[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 Cailure modes. As such, pavement design can be considered a compromise between a high initial cast and low maintenance costs versus a low initial cos[ and higher maintenance costs_ 4.6 Structural Fill 'Che tern "strucmral fill" refers to any placed under foundations, retaining walls, slab-on-grade floors, sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning structural fill aze presented in the following pazagraphs. Materials: Typical structural fillmaterials 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 ofsi$, sand, and gravel Recycled asphalt, concrete, and glass, which are derived from pulverizing the parent materials, are also poten[iallyuseful as structural fill in certain applications. Soils used for structural fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches N 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 Modified Proctor test (ASTMI?1557) as a standard, we recommend that stmctural fill used for various on-site applications be compacted to the fol lowing minimum densities: Fill Application Minimum Compaction Footing subgrade and bearing pad 95 percent Foundation backfill 90 percent Slab-on-grade floor subgrade and subbase 95 percent Pavement Subgrade (upper 2 feet) 95 peroent Pavement Subgrade (below 3 feet) 90 percent Subp~~ade Observation and Comnac[io T stiue: Regardless ofmaterial or locafion, all structural fill should be placed over firm, unyielding subgrades prepared in accordance with the Site Prepararion 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 place went so th : aderjoacy of soil ocr..pac5on eficYS may be e-vaFaated as ea uS'wcrk processes. January 5. 2007 -'RA. Inc. ?Gc39%; Y~!m Dentzl Soil Nloismre Considerations: The suitability of sots used for structural fill depends primarily on their gain-size distribution and moisture content when they are placed. As the'Ynes" content QhaT SOii fraction passing the U.S-No. 200 Sieve) increases, soils become more sensitive to mall changes in moisture ecntemt. Soils containing more than about 5 percent fines (by weight) cannot he consistently compacted to a frm, unyielding condition when the moisture content is more than 2 pcaentage points above or below optimum- For fill placemem dortng 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 RECOMMENDED AllD[T[ONAL SEI2VICF.S Necause the future performance and integrity of the structural demen6 will depend largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced geo[echnical personnel should be considered an integral part of the constrmction process. Consequently, we rtcommend that E3I2A be retained to provide Lhe following posbreport services: Review all construction plans and specifications to verify That our design criteria parented in this aport have been properly integrated info the design; Prepare a letter addressing relevant review comments (if required by the CiTy ofYelm); Check all completed subgades for footings and slab-oo-grade floors before concrete is poured, in order to verify their bearing capacity; and Prepare a posUCOnstruction letter summarizing atl field observations, inspections, and test results (if aquited by the CiTy of Sumner). 6.0 CLOSURE The conclusions and recommendations presented in this report are based, in part, on the explorations that we observed for [his study; therefore, ifvariations in the subgrade conditions are observed at a later time, we may need to modify this report to reflect those changes. Alsq because the future perfomrance and integrity oftuc project elements depend largely ou proper initial site prepzration, drainage, and wnstruction procednres, monitoring and testing by experienced geotechnieal persomrel should be wnsidered an integral part of the construction process. E3RA is available to provide geotechnical monitoring of soils tlrroughout construction. January 5. 2607 T0G397 / , a'~.m Mental z_, E~rv~. Inc_ Weappreciate the opportunity to be of service on this project ITyou have any yuestions regarding [his report or any aspects of the projecS please feel free m contact ouroffce_ S inccrcly_ E3RA, Inc, rr i i Casey R. Lowe, E.1.T. Staff Engineer James G Brigham, P.H. Principal Engineer CRL/JEB Enclosureo': Figurel Location Map Figurel Sife&6zploration Plan Attachment Test Pif Logs TP-L through TP-3, Sieve Analysis ~ 3- i ~- ~~ January 5. 2007 T063971 Yeim Dental E3RP~ Inc. TDST P[T LOGS -Yeim Dental Office Depth (1'eeq Material Descripfion Sample A'o. reel Pit ~rP-I Location: Parkin, a[exis[ine deutaloffice Approximate gnound surface elevation: Unknown 00-07 Crushed rock 0.7- 2.0 Medium dense, moist, black ash stlry sandy gravel with boulders and arbbles (SP-SM) S-1 2.U-95 Medium Dense, moist, [an sandy gravel w/silt, cobbles, and boulder (SP). S2 Test pit terminated at approximately 95 feet Moderate cavine observed at 4.5 feet No groundwater or mottling noted Depth (feet) Material Description Samnle No. Test Pit TP-2 Loce[io¢ Existing home Gont yard Approximate ginwd sartace elevation: Unknowr. 0.0-0.5 Top Soil 0.7-25 Medium dense, moist, black ash slty sandy gravel with boulders and cobbles (SP-SM) 25 - 10.0 Medium Dense, moist, too sandy gravel w/silt, cobbles, and boulders (SP). S] 'Celt pit terminated xt approximately l0 Cect Moderate caving observed at 5 feet No groundwater or mottling noted Uepth (feed Material Description Sample Nn. Test Pit TP-3 Location: Existing home backyard Approximate ground surface elevation: Onknown 0.0 - 0.6 Crushed rock 0.6-20 Medium dense, moist, black ash silty sandy o avel w/boulders and cobbles (SP-SM) 2.0-5.5 Medium Dense, moist, tan sandy gravel with silS cobbles, and boulders (SP). SS - 10.0 Medium Dense, tan sandy gravel/gravelly sand (SP). S-1 ies[ pi[ terminated at approximately 10 feet Slight cavirle observed at 55 feet No groundwaee[ or mottling noted lJate Excavated 11/15/06 Logged by: CAi. Particle Size Analysis Summary Data Job Name_ Yelm Dental Office Jab Number: T06397 Tested By: ALH Date_ 11/20/06 Boring #: Perc #2 Sample #: S-i Depfh_ 5' Moisture CaNent (%) 5.1 Sieve Size Percent Passing (%) 30is Q60 100.0 L5 In. (37.5) 78 5 3/4 in. 19.0) 56.0 3/8 in. (9-5-mm 36.6 No. 4 (4.75-mm) 30.1 No. 10 2.00-mm) 10.5 No. 20 (.850-mm) g q No. 40 (.425-mm) 7] No. 60 (.250-mm) 6.2 No. 100 .150-mm) 5.5 No. 200 (.075-mm) 5.2 Size Fracfion Percent By Weighf Coarse Gravel 44.0 Fine Gravel 26.0 Coarse Sand 19.5 Medium Sand 29 Fine Sand 25 Fines 5.2 Total 100.0 LL PI D10 1.35 D30 4.74 D60 21.42 Cc 0.78 Cu 15.92 C ASTM ClassificaRon Group Name Brown poorly graded gravel with silt and santl Symbol (GP-GM) /{~ Figure ~~~ I Soii Classiticaiion Da[a Sheet C O N ^~ F n JI ^ 0 a 0 N n E N 0 ~ N N a a ~ y U `m ° a m m h _ o o ~I V o D O E E N ti v C A a y o ~ m 0 6 m m ~ 0 0 0 0 0 0 I~ [D V [7 N 6mssed ~uaaad -- - -. a ~ ~ .•I h ~~ i' 4 ~ ~ ~ i ~ ' ~ ~ I . ~ ' ~ I ~ ' ~ ~ ~ ~_- __ ..~ ti - -----. ~ ~<; ~: ~ -~ ,- ,~ -. F NOTE: PROJECT: Yelm Dental Center BOUNDARY AND TOPOGRAPHY ARE BASED ON MAPPING PROVIDED TO E3RA AND OBSERVATIONS TITLE: Site and Ex IoratiOn Plan MADE IN THE FIELD. THE INFORMATION SHOWN P DOES NOT CONSTITUTE A FIELD SURVEY BY E3RA TEST PIT LOCATION DESIGNER: CRL FIGURE 2 TP-1 DRAWN BY: CRL SCALE: 8 CHECKED BY: JEB SHEET: 1 DATE: 1/2/07 FILE:T06397 APPENDIX D STORM DRAINAGE CALCULATIONS STOAMWATER MANAGEMENT MANVAL FOR THE PUGET SOUNO BASIN STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN ,~ 65 \ ll-~ 1 75 j as esti - } ~aa~ ~, ~ a 1' _ - iFILLV tlAP~ P ~ ~~ • OR* i2/ 3S 70~~ ,,_`~T ~le qc vs ~ ,tom 121 SItE /,otAtlonl 10 6 50 /0 ¢Bu WASHINGTON ~ 15 ~ - ---- ', 10 0 10 20 30 40 t I i!~ ~ I~F : EM E ~~ MILES /0 ima Figure30 ~ ~. ~ ~ Bn uurs3f-~ _ \~~- 1 /a NDgA giLAi ; VoWme IX T ! J ISOPLUVIgL$ F 300~YR 24-HR PRECIPITATION SO SS 60 65 i Preivrea M us Dep.nmem or cd„mem IN TENTHS OF N INCH : Mlnonlioconeenegtmoegrcnc qff mretiee 'NUianal WeetM1er Servicq DMice or HYOrlIUBy ~ ReprM ror U.i DlWtlm t of q icultw5 ' Seil Gnaervenm serviu, EnBinee.~ng DIVIfIOn 124 123 ~ 122 12! III-1-46 FEBRUARY, 1992 ~~ ~~ StormTECH Routing Summary 100 Vr Match O: 0.1595 cfs Peak Out C: 0.1595 cfs Peak Stg: 103.27 ft Active Vol: 1094.47 cf Match O: 0.1595 cfs Peak Out D: 0.1595 cfs Peak Stg: 100.68 ff Active Vol: 117.43 cf Project Precips [2 yrJ 2.70 in [100 yrJ 5.30 in [6 mo[ 1.73 in Hydrograph ID: 100 yr Out (24-hour) Area: 0.5370 ac Hyd InC 10.00 min Peak Flow: 0.1595 cfs Peak Time: 6.83 hrs Hyd Vol: 0.1969 acft Hydrograph ID: 2 yr Out (24-hour) Area: 0.5370 ac Hyd InL 10.00 min Peak Flow: 0.1595 cfs Peak Time: 7.67 hrs Hyd Vol: 0.0884 acft Drainage Area: Total Site (24-hour CN) Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10.00 min Area CN TC Pervious 0.1850 ac 80.00 0.08 hrs Impervious 0.3520 ac 98.00 0.08 hrs Total 0.5370 ac Supporting Data: Pervious CN Data: Landscaping 80.00 0.1850 ac Impervious CN Data: Pavement and Sidewalks 98.00 0.2250 ac Building Roof 98.00 0.1270 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed Assume 5 min 0.00 ft 0.00% 5.0000 5.00 min Impervious TC Data: Flow type: Description: - Length: Slope: Coeff: Travel Time x_AS~u~iosVGSrllA06W~AObl<biotlays_~en~alADezlgnASlormVCaloAFnal Calcula~lanz\Fnol Storm ~m~nage Calarlotlompoc SlormSHtp Calculolbns lob NU/Protect. 0624]Tatlay sDenlal Dalx_03/I4/CB ~~ ~~ f1y:Ll Fixed Assume 5 min 0.00 ft 0.00 % 5.000 0 5.00 min BasinlD Peak Q Peak T Peak Vol Area Method ftaintype Event ---- (cis) (hrs) (ao-fQ ac (Loss Total Site (24-hour CNl 0.14 800 00505 0.54 SBUHISCS TVPEIA 6mo Tatel Slte (24~hour CN) 0.25 8.00 0.0883 0.54 SBUHISCS TVPEIA 2 yr Total Slle (24-hour CN) 0.5] 8.00 0.19]2 054 SBUH/SCS TVPEIA 100 NodelD:StormTech Start EI: 100.0000 ft Max EI: 104.0000 ft Contrib Basin'. Contrib Hyd: Stage Input Volume Volume 100.00 0.00 cf 0.00 cf 0.0000 acfl 100.50 86.00 cf 86.00 cf 0.0020 acfl 101.00 172.00 cf 172.00 cf 0.0039 acfl 101.50 413.00 c( 413.00 cf 0.0095 acfl 102.00 641.00 cf 641.00 cf 0.0147 acfl 102.50 850.00 cf 850.00 cf 0.0195 acfl 103.00 1030.00 cf 1030.00 cf 0.0236 acfl 103.50 1150.00 cf 1150.00 cf 0.0264 acfl 104.00 1236.00 cf 1236.00 cf 0.0284 ack Storage provided by 17 Sto rmTech cha mbers with 12 inches of stone base and 6 inches of stone cover Stage-Storge Table for node StormTech Stage Vol Vol Stage Vol Vol (R) (cf) (ac-ft) (ft) (cf) (ac-ft) 1oo.po ooo ooopo mz.zp na.6o oolss 10o.m nsp opppa mz5a ]sego op12s 100 20 34 00 0.0008 102.40 808 20 0.0186 100.30 51.60 0.0012 102.50 850.00 0.0195 100.40 68.80 0.0016 102.60 686.00 0.0203 100.50 8600 0.0020 102]0 922.00 0.0212 100.60 103 20 0 0024 102.60 958.00 0 0220 100.]0 12040 00028 102.90 994.00 00226 100 80 13] 60 0.0032 103.00 1030 00 0.0236 100 90 154.80 0.0036 103.10 1054 00 O.p242 101.00 18.00 0.0039 10320 1076.p0 0024] 101.10 220.20 0.0051 10330 1102.p0 p.0253 tOt2p 266.40 0.0062 103.40 1126.00 p.0258 101.30 31660 0.00]3 103.50 1150.00 0.0264 10144 364.80 0.0084 143.60 118].20 0.0268 10150 413.00 0.0095 103.]0 1184.40 0.02]2 10160 45860 Op1p5 103.80 120160 0.02]6 101.]0 504.20 00116 103.90 121880 0.0280 101.80 54980 0.0126 104.00 1236.04 0.0284 101.90 595.40 0.013] 1pz.0p s41.pp o.p1m 102.10 682.80 0 015] X\SlutlimACivlAOLO~Va62dNOtlays ~enlalA~esignU~wmVCalcs\Fnal Calculatlans~Fnal Aortn oiohQae calmmnoneaoc 2p ~7 ~~ nrNFtU Calcolo'ions -ob NO./ProjecP. 0624'2 Totlay's Deniol Dale. 03/14 Control Structure ID: ChamberBottom -Stage Discharge rating curve Descrip: Multiple Orifice Start EI Max EI Increment 100.0000 ft 104.0000 ft 0.10 Approximate trench footprint: 689.17 ft2 10 in/hr' 0.08333 ft/in '0.0002778 hr/sec ' 689.17 ft2 = 0.1595 cfs Stage-Discharge Table for control: ChamberBottom Stage Discharge Stage Discharge (%) (cfs) (ft) (cfs) 1oB.oc o.l sss 1n2.1B o.15ss 100 10 0.1595 102 20 0.1595 100 20 0.1595 102.30 0.1595 100.30 0.1595 102.40 0.1595 10040 0.1595 102.50 0.1595 100.50 0.1595 iW.60 0.1595 100.60 0.1595 102.]0 0.1595 100.]0 0.1595 10280 0.1595 100.80 0.1595 102.90 0.1595 100.90 0.1595 103 00 0.1595 10100 0.1595 103.10 0.1595 101.10 0.1585 103.20 01595 101.20 0.1595 103.30 0.1595 101.30 0.1595 103.40 0.1595 10140 0.1595 103.50 0.1595 101.50 0.1595 103 60 0.1595 101.60 0.1595 103.]0 0.1595 101]0 0.1595 103.80 0.1595 101.80 0.1595 10380 0.t 595 10190 0.1595 104.00 0.1595 102.00 0.1595 x_~SNtliozVCMh060.'OA062a4-IaOays_~eniah~es~gnA5lormVCalaAFnm CalalaAons\Fna6loim Ominoge Colamiions tloc p/~ Number of Chamber In eed- 1] ~p~~meer~o~tl,~~~baa~oaa- pap StormTech° StormTech SC 740 Incremental Storage Volumes Heigh) o! Cumulative Total System System (In) Chamber (f1a) Storage (p') Storage QI') Volume (flat 48 0 0 85 72.73 1236 4] 0 0.85 ]1.89 1222 46 0 0.85 ]1.04 1208 45 0 p.B5 ]020 1193 44 0 0.85 69.35 11]9 43 0 0.85 68.51 11fi5 42 0.05 0.88 6] 66 1150 41 o.1fi 0.96 66.78 1135 40 0 28 1.04 65.82 1119 39 060 L2] 64.7] 1101 38 0_BO 141 63.51 1p80 37 0.96 1.61 62.10 1056 36 1.07 1.60 60.59 1030 35 1.18 16] 58.99 1003 34 12] 173 5732 9]4 33 1 36 1 ]9 55 59 945 32 1.45 1.86 53.80 915 31 1.52 1.91 57.93 883 30 1.58 195 Sp D2 850 29 1.64 1.99 48.07 817 28 Vp 2.03 460] 783 2] 175 20] 4404 749 26 1.80 2.11 41.97 713 25 1.85 2.14 39.86 678 24 1.89 2.1] 37]2 fi41 23 1.93 2 20 35.55 604 22 1.97 2.23 33.35 567 21 2.01 2.25 31.12 529 20 2.04 2.28 28.8] 491 19 2.0] 2.30 26.59 452 18 2.10 2.32 24.29 413 17 2.13 2.34 21.97 374 16 2.15 2.35 19.64 334 15 2.18 2.37 17.28 294 14 220 2.38 1492 254 13 221 2.39 12.53 213 12 0 0.85 10.14 172 11 0 0.85 9 30 158 10 p 0.85 845 144 9 0 0.85 ].61 129 8 0 0.85 fi]6 115 7 0 p.85 5 92 101 6 0 0.85 507 e6 5 0 0.85 4.23 ]2 4 0 0.85 3.38 57 3 0 0.85 2.54 43 2 0 0.85 1.fi9 29 1 0 0.85 0.85 14 1273 coral [pamper Storage= 459ry~ Calcularlons are basetl upon a rP Incb stone base antler Pe cbambers ~~ ~~ sm~~~seeo caicoia~ionz CONVEYANCE CALCULATIONS Manning Pipe Calculator Givenlnput Data Shape ................. .......... Circular Solving for ........... .......... Depth of Flow Diameter ............. ........... 0.6700 ft Flowrate ............. ........... 0.5700 cfs Slope .................. ......... 0.0050 ft/ft Manning's n .......... ........... 0.0130 Computed Results: Depth ........................... 0.3967 ft Area ............................ 0.3526 ft2 Wetted Area .................... . 0.2174 ft2 Wetted Perimeter ............. ... 1.1765 ft Perimeter ....................... 2.1049 ft Velocity ........................ 2.6221 fps Hydraulic Radius ............... . 0.1848 f Percent Full .................... 59.2088 Y Full flow Flowrate ............. . 0.8659 cfs Full flow velocity .............. 2.4560 fps Critical Information Critical depth ........... Critical slope ............ Critical velocity ......... Critical area ............. Critical perimeter ...... Critical hydraulic radius Critical top width ....... Specific energy .......... Minimum energy ........ Froude number .......... Flow condition ........... case. PIPE 1S or1DY 5`1.Z% F/U. pveWG Iou-'2 51-oeM E~F•NT boo-'(R stoKM Fa16t1T MR)1MU M hAW~'cfE (0.51 CK~ is tiiSS 'CNAt~ PIPE GAPAUL`~ 0.3540 ft 0.0072 ft/ft 3.0160 fps 0.1890 ft2 1.0904 ft 0.1733 ft 0.6700 ft 0.5031 ft .. 0.5309 ft . 0.8123 Subcritical x \$IVtllmACinlA06W9A06242iotloy DBn~alADUgnASlartnACal¢AFnol ColculollomVCnmeyanca Col[ulolia~gOC I/I APPENDIX E WATER QUALITY CALCULATIONS ~7 ~~ so~o~sHEO caiCOiarto~, 10o No./a.oie=v. ass<: WATER QUALITY CALCULATIONS o~ie: Water Quality Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method Raintype Event ------ (cfs) (hrs) (ac-R) ac /Loss Water Quatlty 0.11 8.00 0.0404 0.41 SBU H/SCS TVPEIA 6mo Drainage Area: Wate r Quality Hyd Method: SBUH Hyd Loss Method : SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur: 24.00 hrs Intv: 10. 00 min Area CN TC Pervious 0.1650 ac 80.00 0.08 hrs Impervious 0.2250 ac 98.00 0.08 hrs Total 0.4100 ac Supporting Data: Pervious CN Data: Landscaping 80.00 0.1850 ac Impervious CN Data: Pavement and Sidewalks 98.00 0.2250 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed Assume 5 min 0.00 ft 0.00% 5.0000 5.00 min Impervious TC Da[a: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed Assume 5 min 0. 00 ft 0.00% 5.0000 5.00 min Q„.q, veak = 0.11 efs Use 18" tall cartridges with flowrate of 15 gpm 449 gpm N~o,,,;ega, = 0.1 I cfe ~ cfs = 329 l5- 8Pri+ carfidge Use 4 StormFilter® cartridges s~s~am,ro~o~oemo~oevalmars oemonoe~ia~~smm,wa~s~e~ai coi~~ioro~,~e„oi waie.¢„ony commm~o~~eo~ ,/~ APPENDIX F OPERATIONS AND MAINTENANCE MANUAL Maintenance Plan Introduction/Project Description The site stormwater management facility consists of a storm drain conveyance system for a new dental office building and adjacent parking lot. A conveyance system will collect runoff from the asphalt pavement and building roof. Treatment of the runoff from the asphalt parking area will be accomplished by routing it through a manhole that contains three StormfilterO cartridges. It will then be routed to a single underground Stormtech®infiltration basin. The runoff from the building roof will bypass the treatment manhole and flow directly to the Stormtech® system. The on-site storm system will require regular maintenance. Inspection of the conveyance system should take place following any significant storm events. If leaves and other debris have accumulated at the catch basin grates, they should be removed. Annual maintenance of the Contech StormfilteO and Stormtech® system are required. See Attachment "C" and Attachment "D" for the respective maintenance manuals. Also, sediment should be periodically vacuumed out of the catch basin sumps. The property owner will be responsible for maintenance of the storm drainage system. The Operations and Maintenance Manual must be kept on site. The attached checklists indicate maintenance actions that must be performed in order to keep the system functioning properly. Maintenance Schedule The detailed maintenance schedule is shown in Attachment "A" of this plan. It should be closely followed to keep the system functioning properly. Additional maintenance may be required as a response to unusual storm events. Estimated Cost The estimated annual cost for maintaining the conveyance system is shown below. It includes costs associated with debris removal, pipe cleaning, and catch basin cleaning. The costs are simply and estimate. They should be revised after construction is complete. Maintaining vegetation Personnel C~ $25/hour for 30 hours $750 Pipe and catch basin cleaning Personnel and vacuum truck Ca $700/hour for 6 hours $600 Cleaning Stormtech system Personnel and vacuum truck @ $100/hour for 3 hours $300 Cleaning/Replacing Storfilter~ cartridges $205/cartridge for 4 cartridges $820 $2,470 Attachment "A" Maintenance Program Cover Sheet Inspection Period: Number of Sheets Attached: Date Inspected: Name of Inspector: Inspector's Signature: Instructions for Use of Maintenance Checklists The following pages contain maintenance requirements for most of the components that are par[ of your drainage system. It also contains requirements for some components that you may not have. Ignore any requirements that do not apply to your system. Let the County know if there are any components that are missing from these pages. You should plan on completing a checklist for all system components on the following schedule: (1 J Monthly from November through April (2) Once in late summer (preferably September) (3) After any major storm (use 1-inch in 24 hours as a guideline) Make photocopies of these pages and check off the problems you looked for each time you made an inspection. Add comments regarding problems found and actions taken. Keep these "checked" sheets in your files because they will be used to write your annual report. No. 2 -Infiltration fYl~rnfgnar?ypr OafepE. ; ,u [angtbPns Nlhen t+~A(nt9nMnceils ~ tiRbdlt§ cted ~4PS n ~`d>in~}ttnedt .r . ~ n ~NEeded ~ ~ Itlaintonan Is ` ` . _.. ..... ..... .... ..... . n_. .... . . , .... ,.. .,. ... .: ..........,. ..... _.. .._... General Trash 8 Dehris See "Detention Ponds' (No. 1). See "Detention Ponds" (No. 1). PoisonousMoxious See "Detention Ponds" (Na. 1). See "Detention Ponds" Vegetation (No. 1). Contaminants and See "Detention Pontls" (NO. 1). See "Detention Ponds" Pollution (No. i). Rodent Holes See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1) Storage Area Sediment Water ponding in infiltration pond after Sediment is removetl rainfall ceases and appropriate time and/or fadlity is deaned allowed for infiltration. so that infiltration system works according to (A percolation test pit or test of fadlity design. intlicates fadlity is only working at 90 % of its designed capabilities. If twn inches or more sediment is present, remove). Filter Bags (if Filled wtth Sediment and tlebds fll bag more than 1/2 Filter bag is replaced or applicable) Sediment and (ult. system is redesigned. Dehds Rack Filters Sediment and By visual inspection, little or no water Flows Gravel in rock filter is Debris through filter tludng heary rain storms. replacetl. Side Slopes of Erosion See "Detendon Ponds" (No. 1). See "Detemion Ponds" Pond (No. 1). Emergency Tree Growth See "Detention Ponds" (No. 1). See "Detention Ponds" Overflow SPiIIwaY (NO. 1). and Berms over 4 (eat in height. Piping See "Detention Pontls" (No. 1). Sea "Detention Ponds" (NO. 1). Emergency Rack Missing See "Detention Ponds" (No. 1). See "DeleMion Ponds" Overflow Spillway (No. 1). Erosion See "Detention Ponds" (No. i ). See "Detention Ponds" (NO. 1). Pre-settling Fedlity or sump e" or designed sedimem trap depth of Sediment is removed. Ponds antl Vaults filled wtlh Sediment setlimeM. anNOr debris February 2005 Volume V - Runo/(Treatment BMPs 4J3 No.5-Catch Basins General x[lete~. x r„. ' afidpMlQplIR 1Nh4R MalatRR871q@IaxMEal}@;,]:."a .PGLS ExPgeted.Wbdn ~". f ~ E x a rx ~ryai~tenpnd'e;s Trash & Trash or debris which is located immetliately No Trash or debris located Debris in front of the catch basin opening or is immediately in front of blocking inletting capacity of the basin by catch basin or on grate more than 1l7%. opening. Trash or dehris (in the basin) that exceeds 60 No trash or debris in fhe percent of the sump depth as measured from catch basin. the bottom d basin to invert of the lowest pipe into or out of the basin, but in no wse less than a minimum of six inches Gearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlei and outlet pipes free blocking more than 1/3 of its height. Mfresh or dehris. Dead animals or vegetation that could No dead animals or generate odors that could cause cemplaims vegetation presets within or dangerous gases (e.g., methane). the catch basin. Sediment Sediment (in the basin) that exceetls 60 No sediment in the catch percent of the sump depN as measured from basin the bottom of basin to invert of the lowest pipe into or out d the basin, but in no case less than a minimum of 6 inches Gearance from the sediment surface to the invert of the lowest pipe. Strocure Tap slab has hdas larger than 2 square Top slab is free M holes Damage to inches or cracks wider than 1/4 inch antl cracks. Frame end/or Top Slab (Intent is to make sure no material is running into basin). Frame rwt sitting flush on top sleh, i. e., Frame is sitting flush on separation of more than 3/4 inch of the frame the riser rings or top slab from the top slab. Frame nd severely and firmly attached. attached Frecures or Maintenance person judges that structure is Basin replaced or repaired Crecka in unsound- to design standards. Basin Walls/ Bottom Grout fillet has separetetl or cracked witler Pipe is regrouted and than 12 inU and longer than 1 fod at the secure at basin wall. joint of any inleVcutlet pipe or any evidence of soil partiGes entering catch basin through cracks. Settlement/ If failure of basin has createtl a safely, Basin replaced or repaired Misalignment func5on, or design problem. to design standards. Vegetation Vegetation growing across and blocking more No vegetation blocking than 10% of the basin opening. opening to basin. Vegetation growing in inlet/ou[let pipe jdnts No vegetation or root that is more than six inches tall and less than grovrth presets. six inches apart. 436 Volume V - RunoNTmatment BMPs February 2005 No. 5 -Catch Basins Yt(~~Rlt~ ~¢r ~~ ~`3°^ ` ipp~{~a r °~ e S it ~ ~Y 3 CogCtty~gd~ 3'Wq~DJMOlnteii$ftt~e rsYNee~uded .. 1 ++~~P`St^S~iJd~b'L 4 ty `Rtt a j{yRyAsr7lEs Eripe~.}cte{IlNhe$n Q: Gei18 ~-. !tom fMal( ]~~ ~ `t " y [ y .L 4 rz ~ PPP ~ ~ S 4.. Fem "2 j ~ r ..t: L Y C:tS.~ ~ M Y ~a~.t.3..k~...1. y y t ~^ '~ Pti 4~ ~ t ~r; t C~ . ... ..... r~O lna .....1 C . . . ...L~ .. Contamination See "DeleMion Pontls" (NO. 1). No pollution present. and Pollution Catch Basin Cover Not in Cover is missing or only paNally in place. Catch basin cover is Cover Place Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person vrith proper tools. Bolls proper tools. Not Working into frame have less than tY2 inch of thread. Cover Difficult One maimenance person cannot remove lid Cover can be removed by to Remove aker applying normal lifting pressure. one maintenance person. (Intent is keep cover from sealing oR access to maintenance.) Ladder Latltler Rungs Ladder is unsafe due to missing rungs, not Latlder meets tlesign Unsafe severely attachetl to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate opening Greta with opening wider than 7/e inch. Grate opening meets (If Applinble) Unsafe design standeMs. Tresh and Tresh antl debris that is blocking more than Grate free of trash antl Debds 20%ot grate audece inletting capedty. debde. Damaged or Orete missing or broken member(s) of the Grate la In place arM Missing, grate. meets deelpri eterldeMa. C ~`.' Fe6mary 2005 Volume V-Run°fl TreafinentBMPs 4.37 No. 15 - StormfllterT'^ (leaf compost filter) ¢~Alt3tenarrce }natset ~. ~- cmfiuvetm,®a~u~ntanance r§ ~ "~jasgl4g~CF§dyJjUC7d a nenE~ -, q'eiYtli ~ i F : r r ifeedad' rr rxx r 'ton tPett'dktnaa ~l : ., ....._ ....... . :. ,.._..€: ...t:,. t i $ _ k..: a ~ Below Ground Sediment Sediment depth exceeds C.26-inches. NO Sediment tleposits which Vault Accumulation on wnultl impede permeability of '' Media. the compost media. Sediment Sediment depth exceeds 6-inches in first No sediment tleposits in vault Accumulation in chamber. bottom of first chamber. Vault Trash/Debds Trash and debris accumulated on Trash antl debris removed fmm Accumulation compost flier bed. the cempost filter bed. Sediment in When drain pipes, clean-outs, become Sediment and debris removed. Drain full with sediment and/or debris. Pipes/Clean- Outs Damaged Pipes Any part of the pipes that are crushed or Pipe repairetl and/or replacetl. damagetl due to corrosion and/or settlement. Access Cover Cover cannot be opened; one person Cover repaired to proper Damaged/NOt cannot open the cover using normal working specifcations or Working lifting pressure, conosioNdeformation of replaced. cover. Vault Structure Cracks wider than 1/2-inch or evidence Vault replaced or repairs made Includes Cracks of soil partides entering the structure so that vault meets design in Wall, Bottom, through the cracks, or spedfications and is structurally Damage to maintenance/nspection personnel sound. Frame and/or tletermine that the vault is not structurally Tap Slab sound. Cracks wider than 12-inch at the joint of Vault repaired so that no cracks any inlef/ouflet pipe s evidence of soil exist under than 7/flinch at the partiGes entering through the cracks. joint ofthe inlet/o Wet pipe. Baffles Baffles corroding, sacking warping, Baffles repaired or replaced to and/or shovnng signs of failure as spedfiptions. determined by maintenencelnspection perm. Access ladder Ladder is corroded or detedsatetl, rrot Ladder replacetl or repairetl and Damagetl functioning properly, rpt severely meets spedfcadons, and is attached to structure wall, missing rungs, safe to use as determinetl by cracks, and misaligned. inspection personnel. Below Ground Compost Media Drewdown of water through the media Media car6idges replaced. Cartridge TYPe takes longer than 1 hour, and/or overflow occurs frequently. Short Circuiting Flows tlo not properly enter filter Filter cartridges replaced. cartdtlges. February 2005 Volume V -Runoff Treatment BMPs 4-47 Attachment "B" Pollution Source Control Program Pollution source control is the application of pollution prevention practices to prevent contamination of stormwater runoff. The applicant/owner shall be responsible for controlling potential pollutants at their point of use or generation. The plan of action will include elements such as centralized area for storage of equipment, lubricants, pesticides, etc. The owner may elect to follow the detailed guidance on control of non-sediment pollutants as outlined in the DOE Manual. The most important practice is to ensure that no hazardous wastes, such as oil, shall be dumped into the storm drainage system. "Dump No Waste" shall be stenciled near each catch basin. The relevant pollution control section from the DOE manual is included as part of this attachment and is an integral part of the plan. BMPs for Description of Pollutant Sow~ees: Landscaping can include grading, soil Landscaping transfer, vegetation removal, pesticide and fertilizer applications, and and Lawn/ wattling. stormwater contaminants include toxic organic compounds, Vegetation heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and Management pesticides. Lawn and vegetation management can include control of objectionable weeds, insects, mold, bacteria and other pests with chemical pesticides and is conducted commercially at commercial, industrial, and residential sites. Examples include weed control on golf worse lawns, access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs, rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential lawn/plant care. Toxic pesticides such as pentachlorophenol, earbamates, and organometallics can be released to the environment by leaching and dripping from treated parts, container leaks, product misuse, and outside storage of pesticide wntaminated materials and equipment. Poor management of the vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater wntamination. Pollutant Control Approach: Control of fertilizer and pesticide applications, soil erosion, and site debris to prevent contamination of stormwater. Develop and implement an Integrated Pest Management Plan (IPM) and use pesticides only as a last resort. If pesticides/herbicides are used they must be carefully applied in accordance with label instmctions on U.S. Environmental Protection Agency (EPA) registered materials. Maintain appropriate vegetation, with proper fenilizer application where practicable, to control erosion and the discharge of stormwater pollutants. Where practicable grow plant species appropriate for the site, or adjust the soil properties of the subject site to grow desired plant species. Applicable Operational B1NP5 for Landscaping: • Install engineered soil/landscape systeme to improve the infiltration and regulation of stormwater m landscaped areas. • Do not dispose of collected vegetation into waterways or store drainage systems. Recommended Additional Operational BMPs for Landscaping • Conduct mulch-mowing whenever practicable • Dispose of grass clippings, leaves, sticks, or other collected vegetation, by composting, if feasible. 1. . February 2005 Volume IV - Soume Control BMPs 2-23 Use mulch or other erosion control measures when soils are exposed for more than one weck during the dry season or two days during the rainy season. • If oil or other chemicals are handled, store and maintain appropriate oil and chemical spill cleanup materials in readily accessible locations. Ensurc that employees are familiar with proper spill cleanup procedures. • Till fertilizers into the soil rather than dumping or broadcasfvrg onto the smTace. Determine the proper fertilizer application for the types of soil and vegetation encountered. • Ti}I a topsoil mix or composted organic material into [he soil to create a well-mixed transition layer that encourages deeper root systems and drought-resistant plants. • Use manual and/or mechanical methods of vegetation removal rather than applying herbicides, where practical Applicable Operational BMYs for the Use of Pesticides: • Develop and implement an IPM (See section on IPM at end of BMP) and use pesticides only as a last resort. • Implement apesticide-use plan and include at a minimum: a list of selected pesticides and their specific uses; brands, formulations, application methods and quantities to be used; equipment use and maintenance procedures; safety, storage, and disposal methods; and monitoring, record keeping, and public notice procedures. All procedures shall conform to the requirements of Chapter 17.21 RCW and Chapter 16-228 WAC (Appendix I V-D R.7). • Choose the least toxic pesticide available that is capable of reducing the infestation to acceptable levels. The pesticide should readily degrade in the environment and/or have properties that strongly bind it to the soil. Any pest control used should be conducted at the life stage when the pest is most vulnerable. For example, if i[ is necessary to use a Bacillus thurineiens is application to control tent caterpillars, it must be applied before the oaterpillars cocoon or it will be ineffeotive. Any method used should be site-specific and not used wholesale over a wide area. • Apply the pesticide according to label directions. Under no conditions shall pesticides be applied in quantities that exceed manufacturer's instmctions. • Mix the pesticides and clean the application equipment in an azea where accidental spills will no[ enter surface or ground waters, and will not contaminate the soil. 2-24 Volume IV -Source Control BMPs February 2005 • Store pesticides in enclosed areas or in covered impervious containment. Ensure that pesticide contaminated slonnwater or spills/leaks of pesticides are not discharged to stone drains. Do not hose down the paved areas to a stm-m drain or conveyance ditch. Store and maintain appropriate spill cleanup materials in a location known to all near the storage area. • Clean up any spilled pesticides and ensure that the pesticide contaminated waste.materials arc kept in designated covered and contained areas. • The pesticide application equipment must be capable of immediate shutoff in the event of an emergency. • Do not spray pesticides within 100 feet of open waters including wetlands, ponds, and streams, sloughs and any drainage ditch or chatmel that leads to open water except when approved by Ecology or the local jurisdiction. All sensitive areas including wells, creeks and wetlands must be flagged prior to spraying. • As required by the local government or by Ecology, complete public posting of the area to be sprayed prior to the application. • Spray applications should only be conducted during weather conditions as specified in the label direction and applicable local and state regulations. Do not apply during rain or immediately before expected rain. Recommended Additional Operational B]t1Ps for the use of pesticides: • Consider al[ematives to the use of pesticides such as covering or harvesting weeds, substitute vegetative growth, and manual weed control/moss removal. • Consider the use of soil amendments, such as compost, that are known to control some oommon diseases in plants, such as Pythium root rot, ashy stem blight, and parasitic nematodes. The following aze three possible mechanisms for disease control by compost addition (USEPA Publication 530-F-9-044): 1. Successful competition for nutrients by antibiotic production; 2. Successful predation against pathogens by beneficial microorganism; and 3. Activation ofdisease-resistant genes in plants by composts. Installing an amended soil/landscape system can preserve both the plant system and the soil system more ejjectively. This type of approach provides asoil/landscape system with adequate depth, permeability, and organic matter to sustain itself and continue working as an effective ~ ~ stormwater infrltratian system and a sustainable nutrient cycle. February 2005 Volume IV -Source Control BMPs 2.25 • Once a pesticide is applied, its effectiveness should be evaluated for possible improvement Records should be kept showing the applicability and inapplicability of the pesticides considered. • An annual evaluation prowdure should be developed including a review of the effectiveness of pesticide applications, impact on buffers and sensitive areas (including potable wells), public concerns, and recent toxicological information on pesticides used/proposed for use. If individual or public potablc wclls are located in the proximity of commercial pesticide applications contact the regional Ecology hydrogeologist to determine if additional pesticide application control measures are necessary. • Rinseate from equipment cleaning and/ortriple-rinsing of pesticide containers should be used as product or recycled into product. • The application equipment used should be capable of immediate shutoff in the event of au emergency. For mare information, contact the WSU Extensiott Home-Assist Program, (253) 445-4556, ar Bio-In[egrn7 Resource Center (BIRC), P.O. Box 7414, Berkeley, CA.94707, or the Washington Department ajEcology !o abaain "Hazardous Waste Pesticides" (Publication #89-41); and/or EPA to obtain apublication entitled "Suspended, Canceled and Restricted Pesticides"which lists a[I restricted pesticides and [he speck uses that are allowed. Valuable information from these sources may also be available on the interne!. Applicable Operational BMPs for Vegetation Management: • Use at least an eight-inch "topsoil" layer with at least 8 percent organic matter [o provide a sufficient vegetation-growing medium. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can substantially improve the permeability of the soil, the disease and drought resistance of the vegetation, and reduce fertilizer demand. This reduces the demand for fertilizers, herbicides, and pesticides. Organic matter is the least water-soluble form of nutrients that can be added to the soil. Composted organic matter generally releases only between 2 and 10 percent of its total nitrogen annually, and this release corresponds closely to the plant growth cycle. If natural plant debris and mulch aze returned to the soil, this system can continue recycling nutrients indefinitely. • Select the appropriate turfgrass mixture for your climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endophytic fungi found naturally in their tissues repel or kill common leaf and stem-eating lawn insects. They do not, however, repel root-feeding lawn pests such as Crane Fly larvae, and are toxic to ruminants such as cattle and sheep. The fungus causes no known 2-26 Volume IV -Source Control BMPS February 2005 adverse effects to the host plant or m humans. Gttdophylic grasses arc commercially available and can be used in areas such as parks or golf courses where grazing does not occur 'I~he local Cooperative Extension office can offer advice on which types of grass are best suited to the area and soil type. • Use the following seeding and planting I3MPs, or equivalent BMPs to obtain information on grass mixtures, temporary and permanent seeding procedures, maintenance of a recently planted area, and fertilizer application rates: Temporary Seeding, Mulching and Matting, Clear Plastic Covering, Permanent Seeding and Planting, and Sodding as described in Volume II). • Seleotion of desired plant species can be made by adjusting the soil properties of the subject site. For example, a constructed wetland can be designed to resist [he invasion of reed canary grass by layering specific strata of organic matters (eg., compost forest product residuals) and creating a mildly acidic pH and carbon-rich soil medium. Consult a soil restoration specialist for site-specific wnditions. • Aerate lawns regularly in areas of heary use where the soil tends to become compacted. Aeration should he conducted while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than''/a-inch deep. • Mowing is astress-creating activity for turfgrass. V/hen grass is mowed too short its productivity is decreased and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses, more disease prone and more reliant on outside means such as pesticides, fertilizers and irrigation to remain healthy. Set the mowing height at the highest acceptable level and mow at times and intervals designed to minimize stress on the turf. Generally mowing only 1/3 of the grass blade height will prevent stressing the turf. /rrigation: • The depth from which a plant normally extracts water depends on the rooting depth of [he plant. Appropriately irrigated lawn grasses normally root in the top 6 to 12 inches of soil; lawns irrigated on a daily basis often root only in the top 1 inch of soil Improper irrigation can encourage pest problems, leach nutrients, and make a lawn completely dependent on artificial watering. The amount of water applied depends on the normal rooting depth of the tmfgrass species used, the available water holding capacity of the soil, and the efficiency of [he irrigation system. Consult with the local water utility, Conservation District, or Cooperative Extension office to help determine optimum irrigation practices. February 2005 Volume /V -Source Control BMPS 2-27 Fertilizer Managementr • Turfgrass is most responsive to nitrogen fertilizatioq followed by potassium and phosphorus. Fet'lilization needs vary by site depending on plant, soil and climatic conditions. Evaluation of soil nutrient levels through regular testing ensures the best possible efficiency and economy of fertilization. I'or details on soils testing contact the local Conservation District or Cooperative Extension Service. • Fertilizers should be applied m amounts appropriate for the target vegetation and at the time of year that minimizes losses to surface and ground waters. Do not fertilize during a drought or when the soil is dry. Alternatively, do not apply fertilizers within three days prior to predicted rainfall. The longer the period between fertilizer application and either rainfall or irrigation, the less fertilizer runoff occurs. • Use slow release fertilizers such as methylene urea, IDBU, or resin coated fertilizers when appropriate, generally in the spring. Use of slow release fertilizers is especially important in areas with sandy or gravelly soils. • Time the fertilizer application to periods of maximum plant uptake. Generally fall and spring applications are rewmmended, although WSU turf specialists recommend four fertilizer applications per year. • Properly trained persons should apply all fertilizers. At commercial and industrial facilities fertilizers should not be applied to grass swales, filter strips, or buffer areas that drain to sensitive water bodies unless approved by the local jurisdiction. Integrated Pest Management An IPM program might consist of the following steps: Step 1: Correctly identify problem pests and understand their life oyele Step 2: Establish tolerance thresholds for pests. Step 3: Monitor to detect and prevent pest problems. Step 4: Modify the maintenance program to promote healthy plants and discourage pests. Step 5: Use cultwal, physical, mechanical, or biological controls first if pests exceed [he tolerance thresholds. Step 6: Evaluate and record the effectiveness of the control and modify maintenance practices to support lawn or landscape recovery and prevent recurrence. For an elaboration of these steps refer to Appendix N-F. 2-28 Volume IV -Source Control BMPS February 2005 BMPs for Description of Pollutant Sources: Facilities include roadside catch Maintenance of basins on arterials and within residential areas, conveyance systems, Stormwater detention facilities such as ponds and vaults, oil and water separators, Drainage and biofilters, settling basins, infiltration systems, and all other types of Treatment stornnvater treatment systems presented in Volume V. Roadside catch Systems basins can remove fi-om ~ to I S percent of the pollutants present in Stormwater. Whets catch basins are about 60 percent full of sediment, they cease removing sediments. Oil and grease, hydrocarbons, debris, heavy metals, sediments and contaminated water are found in catch basins. oil and water separators, settling basins, etc. Pollutant Control Approach: Provide maintenance and cleaning of debris, sediments, and oil from Stormwater collection, wnveyance, and treatment systems to obtain proper operation. Applicable Operational BMPs: Maintain Stormwater treattnent facilities according to the O & M procedures presented in Section 4.6 of Volume V in addition to the following BMPs: • Inspect and clean treatment BMPs, conveyance systems, and catch basins as needed, and determine whether improvements in O & M are needed. • Promptly repair any deterioration threatening the structural integrity of the facilities. These include replacement of clean-out gates, catch basin lids, and rock in emergency spillways. • Ensure [hat storm sewer capacities are not exceeded and that heavy sediment discharges to the sewer system are prevented. • Regularly remove debris and sludge from BMPs used for peak-rate control, treatment, etc. and dischazge to a sanitary sewer if approved by the sewer authority, or truck to a local or state government approved disposal site. • Clean catch basins when the depth of deposits reaches 60 percent of the sump depth as measured from the bottom of basin to the invert of the lowest pipe into or out of the basin. However, in no case should there be less than six inches clearance from the debris surface to the invert of the lowest pipe. Some catch basins (for example, WSDOT Type 1L basins) may have as little as 12 inches sediment storage below the invert. These catch basins will need more frequent inspection and oleaning to prevent scouring. Where these catch basins are part of a Stormwater collection and treatment system, [he system owner/operator may choose to concentrate maintenance efforts on downstream control devices as par[ of a systems approach. 2-40 Volume /V -Source Control BMPS February 2005 • Clean woody debris in a catch basin as frequently as needed to ensure proper operation of the catchbasin. • Post warning signs; "Dump No Waste -Drains to Ground Water," "Streams," "Lakes;' or emboss on or adjacent to all storm drain inlets where practical. • Disposal of sediments and liquids from the catch basins must comply with "Recommendations for Management of Street Wastes" described in Appendix iV-G of this volume. Additional Applicable BMPs: Select additional applicable BMPs from this chapter depending on the pollutant sources and activities conducted at the facility. ThoseBMPs include: • BMPs for Soil Erosion and Sediment Control at Industrial Sites • BMPs for Storage of Liquid, Food Waste, or Dangerous Waste Containers • BMPs for Spills of Oil and Hazardous Substances • BMPs for Illicit Connections to Stonn Drains • BMPs for Urban Streets. February 2005 Volume IV -Source Control BMPs 2-41 BMPs for Description of Pollutant Sources: Public and commercial parking lots Parking and such as retail store, fleet vehicle (including rent-a-car lots and car Storage Of dealerships), equipment sale and rental pad<ing lots, and parking lot Vehicles and driveways, can be sources of toxic hydrocarbons and other organic Equipment compounds, oils and greases, metals, and suspended solids caused by the parked vehicles. Pollutant Control Approach: If the parking lot is a high-use site as defined below, provide appropriate oil removal equipment for the contaminated stormwater runoff. Applicable Operafional BMPs: • If washing of a parking lot is conducted, discharge the wastewater to a sanitary sewer, if allowed by the local sewer authority, or other approved wastewater treatment system, or collect it for off-site disposal. • Do not hose down the area to a storm drain or to a receiving water. Sweep parking lots, storage areas, and driveways, regularly to collect dirt, waste, and debris. Applicable Treatment BMPs: An oil removal system such as an API or CP oil and water separator, catch basin filter, or equivalent BMP, approved by the localjurisdiction, is applicable for parking lots meeting the threshold vehicle traffic intensity level of a high-use site. Vehicle High-Use Sites Establishments subject to a vehicle high-use intensity have been determined to be significant sources of oil contamination of stormwater. Examples of potential high use areas include customer parking lots at fast food stores, grocery stores, taverns, restaurants, large shopping malls, discount warehouse stores, quick-lobe shops, and banks. If the PGIS for a high-use site exceeds 5,000 square feet in a threshold discharge area, and oil control BMP from [he Oil Control Menu is necessary. A high-use site at a commercial or industrial establishment has one of the following characteristics: (Gaus/King County, 1994) • Is subject to an expected average daily vehicle traffio (ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross building area: or • Is subject to storage of a fleet of 25 or more diesel vehicles that are over ] 0 tons gross weight (trucks, buses, trains, heary equipment, etc.). 2-48 Volume IV -Source Control BMPs February 2005 BMPs for Roof/ Description of Pollutant Sources: Stormwater runoff from roofs and Building Drains sides of manufacturing and commercial buildings can be sources of at Manufacturing pollutants caused by leaching of roofing materials, building vents, and and Commercial other air emission sources. Vapors and entrained liquid and solid Buildings droplets/particles have been identified as potential pollutants in roof/building runoff. Metals, solvents, acidic/alkaline pll, ROD, and organics, are some of the pollutant constituents identified. Pollutant Control Approach: Evaluate the potential sources of Stormwater pollutants and apply source control BMPs where feasible. Applicable Operational Source Control BMl's: • If leachates and/or ernissions from buildings are suspected sources of Stormwater pollutants, then sample and analyze the Stormwater draining from the building. • If a roof/building stoanwater pollutant source is ideutified, implement appropriate source control measures such as air pollution control equipment, selection of materials, operational changes, material recycle, process changes, etc. Febmary 2005 Volume IV -Source Confrol BMPs 2-51 Attachment "c" Contech Stormfilter® Maintenance Manual STURII9LVATER SOLl1TI0N5 StormFilter Inspection and Maintenance Procedures J Stn!"Il1FI~Yf`I Maintenance Guidelines the primary purpose of the Stormwatcr Management StomrFilter is to flllin Durand prevent pollulan¢ hom entering our waterways. Like any eNeuive (tltration system, periodically these pollutants must he removed to restore the StormFilter to its full efficiency and effectiveness. Maimenance requirements and frequency arc dependent on the pollu lant load charaderisoa of each sac. Maintenance activities maybe required m the even) of a chemical spill or due to exressive 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 arc likely many eficctive 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 detenninc the need for maintenance. Z 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 he done before the winter season. During the inspecton the need for maintenance should be determined and, If disposal during maintenance will 6e required, samples of the accumulated sediments and media should be obtained. ~~ atldiuon to these two activities, it is important [o check the coed uion o(the StormFlter unit after malor storms for potential damage roused by high flows and (or high sediment accarnulation that may be caused by loalizcd erosion In the drainage area. It may be necessary to adjust the inspection/ rnairnena nee schedule depending on the actual operabny conditions encountered by the system. In general, insocchon activities can be conducted at any time, ono maintenance should occur, if warranted, In late summer to early fall when Sows into the system are not likely to be presenC Maintenance Frequency 1 he primary factor controlling timing of maintenance of'hc StormFilter is sediment loading. A properly (u netioning system will remove solids from water by trapping particulates in the porous structure of the filter media inside the cartddges. The flow through the system will na Wrally decrease as more and more partlmlates are trapped. Eventually the flow through the cartridges will be low enough to require replacement. It may he possible to extend the usable span of the cartridges by removing sediment from upstream trapping devices on aroutine az-needed basis in order to prevent material from being re-suspended and discharged to the StormFilter treatment system. Site conditions greatly influence maintenance requirements- StormFilterunits located in areas with erosion or active construction may need to be inspected and maintained more often than those with fully stabilized sudace mndtions. The maintenance frequency may be adjusted as additional monitoring information becomes availahle 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 6e followed. Inspection one time per year After major storms Maintenance As needed, based on results of inspection (The average maintenance lifecyde is approximately 13 years) Per Regulatory requirement In the event of a chemical spill Frequencies should be updated as required. The recommended initial frequency for inspection iz one time per year. StormFilter units should he inspected after major storms. Second, if warranted, a maintenance (replacement of the (Iter cartridges and removal of accumulated sediments) should he performed during periods of dry weather. Sediment removal and cailridye replacement on an as needed basis is recommended unless site conditions wanant Once an undeistandmy of site cnaradenstics has been established, maintenance may not be needed for one m thmc yca~s, bW 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 Sedlment loath rig as it relates to decreased treatment capacity It may tie desirable to conduct this inspection during a storm to observe the relative slow through the filter cartridges- H the submerged cartridges are severely plugged, then typically large amounts of sediments will be present and very tittle flow will be discharged Irom the drainage pipes. If firs 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 Storm Filter treatment unit. 1- If applicoble, set up safety equipment to protect and notify surrounding vehicle and pedestrian traffic 2. Visually inspect the e#ernal condition of the unit and take notes concerning defects problems. 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 an 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 pittures are valuable for historical documentation. b- Close and fasten the access portals. 7. Remove safety equipment. fr. II appmpria:e, make notes about the local drainage area iclatmc m angoing construction, eroson problems, or high loading of other materials to the system. 9. Discuss conditions [hat suggest maintenance and make decision as to weather or not maintenance n needed. Maintenance Decision Tree The need for maintenance Is typiczlly based on results of the inspection. The following Maintenance Dcasion Tree should tie used as ageneral gwde. (Other factors, such as Regulatory Requirements, may need to be considered) a. If >4'" of a¢umulated sediment, maintenance is required- Sediment loading on top of the cartridge. a. If >1/4'" of acmmulation, 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, mairnenance 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 Storm Filter 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 (says 1/4" thick) is present above top cap, maintenance is required. 8. Calendar Lifecyde. a. If system has not been maintained for 3 years maintenance is required. 1 Sediment loading on the vault floor `t~~: Assumptions • No ~ainiall for 2q hours orrnare No upstream detention (a[ lead not draining into StorniFilter) StrucW rc is online Outlet pipe is clear of obrtrucbon Constroction bypass is plugged Maintenance Depending on the configuration of the partlmlar system, maintenance personnel will be my ulred to enter the vault to perform the maintenance. Important. If vault entry is required, OSHA roles (or 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 rase ofa spill, the maintenance personnel should abort maintenanm activites 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 defects7problems. 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-up on 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 1501bs. each) and set asde- 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 (removap. Unscrew (counterclockwise rotafions) each filter cartridge from the underdrain connector Roll the loose cartridge, on edge, to a convenient spot beneath the vault access. Using appropriate hoisfing equipment, attach a cable from the boom, crane, or tripod to the loose cartridge. Contact CONTECH Stormwater Solutions for suggested attachment devices. B. Remove the used cartridges (up to 250 Ibs- 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 ca«ridge cap. C Remove the cartridge hood screws (3) hood and (loaf. D- At locafion under structure access, tip the cartridge on its side. Important: Nate 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. Important: Note That cartridges containing media o!her than the leaf media require unscrewing from their ih readed Connectors. Take care not to damage Pic manifold connecm¢_ This connecmr should remain installed In the manfold and capped if necessary D_ Fmpty the cartridge onto the vault Ooor Reasscmhle the empty ca«ridge. L Set the empty, used cartridge aside or load onto the hauling track. 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 ran most effectively be accomplished 6y 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 outside of the exposed portion of the connectors. This ensures a watertight connection hetween the cartridge and the drainage pipe. b. Replace any damaged connectors. i i. dose and fasten the door. 12. Remove safety cqulpmen t. 13. Finally, dispose of tLe acaimula ted materials in accordance with applicahle regulations. Make arrangements to return the used crnoty carlndycs to COMECH 4armwater Solutions. 10. Using the vacuum truck boom, crane, or tripod, lower and install the new cartridges- Once again, take care not to damage connections. Related Maintenance Activities Performed on an as-needed basis SronnFilter units are open just one o! many structures in a more coin prehensive stormwater drainage and treatment system- In order for maintenance of the Storm Filter m be successful, it is imperative that all other components be properly malntained- The rnaintenance/repair of upstream facihties should he carried out prior to StonnFilter maintenance adivitles. In addition to considering upstream facilities, it Is also important to correct any problems identified in the drainage area. Drainaye area concerns may include- erasion problems, heavy oil loading, and discharges of inappropriate materials- Material Disposal I he accumulated sediment found in riormwater treatment aid conveyance systems must he handled and dsposed of m a¢ordance with regulatory protocols. It'a passble for sediments to contain measura hie concentraLOns of heavy metals and organir chemicals (such as pesticides ono petroleum products). Areas with the greatest pole V ial for high pollutant loading inclutle industrial areas and heavily Vavcled roads. Sediments and water must be disposed of in accordance with all applicable waste disposal regulations. When scheduling maintenance, consideration must be triode 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 rnunidpal vacuum truck decant facilitg local waste water treatment plant or on-site treatment and discharge. AFCVCIFD i vnrEa A_ _r•rrrAu _ .,.rt•o.. .,. 800.925.5240 contechstormwateccom 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.<om 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. ,~ ~.. I Date: - _Pcrso~rnel'. _ Location' _ System Srz e' _. - _ _. SySLem TypCl ~Ja L't ~ CaSFn-PaC2 ' ~, ln2df Catch Rd9n ~. ~ MdnhOC ~ Other Sediment Thickness in Fbicbay: _ _ Date. _ _ _ _ _ _. Sediment Depth on Vault Floor. _ _ Structural Damage Estimated Flow from Drainage Pipes (if available). Cartridges Submerged. Yes ^ No ~ . ~ Depth o(Sianding Water__ _. _ Storm Filter Maintenance Activities (check off if don e and give description) ^ bash and Debris Removal'. _ _ ~ ^ Minor Structural Repairs. _ _ _ ^ Drainage Area Report _ Excessive Oil Loading. Ves ~_~ No ^ Source'. Sediment ACCUmolation an Pavement Yes ~ No ^ Source Erosion of Landscaped Areas Ves ^ No ^ Source Items Needing Further Work. __ I Owners should contact the local puhllc works depa rtment and inquire about how the department d'aposes of their street waste residuals. Other Comments: -_ Review the condition reports from the previous inspection Nzitz. ~ u 11 . r' r. r .• r r Date: - _ __ Permnnd. Location____ _ System Size: _ _ _ System Type. Vault ~ Casbin-Plane ~~ Linear Catch Nasin ~~ Manhole ~i Other List Sa(ery Procedures and Equipment Used_ ~i System Observations Months in Service_ Oil in Forebay: Sediment Depth in horebay. Sediment Depth on Vault Floor. Strurtural Damage_ Drainage Area Report Excessive Oil Loading. Sediment Accumulation on PavemenT. Erosion of Landscaped Areas'. Ves ^ No LJ Yes n No L Source'. Yes ~] No ~ Source: Ves U No ~ Source'. StormFilter Cartridge Replacement Maintenance Activities Remove Trash and Debris'. Ves ^ No ^ Details: Replace Cartridges' Ves ~] No (~ Details- Sediment Removed'. Ves ^ No ~ Details. Quantity o4 Sediment Removed (estimate7). Minor Structural Repairs. Yes ~ No ~ Details. Residuals (debris, sediment) Disposal Methods Noes: A~~I%\ITCAIJ" ~ij~~p~ t ~~ n STORMWATER SOLUTIONS.. Operation and Maintenance CatchBasin StormFilter'M Important: These guidelines should be used as a part of your site stormwater plan. Overview The CatchBasin StormFilterTM (CBSF) consists of amulti-chamber steel, concrete, or plastic catch basin unit that can contain up to four StormFilter cartridges. The steel CBSF is offered both as a standard and as a deep unit. The CBSF is installed flush with the finished grade and is applicable for both constrained lot and retrofit applications. It can also be fitted with an inlet pipe for roof leaders or similar applications. The CBSF unit treats peak water quality design flows up to 0.13 cfs, coupled with an internal weir overflow capacity of 1.0 cfs for the standard unit, and 1.8 cfs for the deep steel and concrete units. Plastic units have an internal weir overflow capacity of 0.5 cfs. Design Operation The CBSF is installed as the primary receiver of runoff, similar to a standard, grated catch basin. The steel and concrete CBSF units have an H-20 rated, traffic- bearing lid that allows the filter to be installed in parking lots, and for all practical purposes, takes up no land area. Plastic units can be used in landscaped areas and for other non-traffic-bearing applications. The CBSF consists of a Bumped inlet chamber and a cartridge chamber(s). Runoff enters the Bumped inlet chamber either by sheet flow from a paved surface or from an inlet pipe discharging directly to the unit vault. The Inlet chamber is equipped with an internal baffle, which traps debris and floating oil and grease, and an overflow weir. While in the inlet chamber, heavier solids are allowed to settle into the deep sump, while lighter solids and soluble pollutants are directed under the baffle and into the cartridge chamber through a port between the baffle and the overflow weir. Once in the cartridge chamber, polluted water ponds and percolates horizontally through the media in the filter cartridges. Treated water collects in the cartridge's center tube from where it is directed by an under-drain manifold to the outlet pipe on the downstream side of the overflow weir and discharged. When flows into the CBSF exceed the water quality design value, excess water spills over the overflow weir, bypassing the cartridge bay, and discharges to the outlet pipe. Applications The CBSF is particularly useful where small flows are being treated or for sites that are Flat and have little available hydraulic head to spare. The unit is ideal for applications in which standard catch basins are to be used. Both water quality and catchment issues can be resolved with the use of the CBSF. Retro-Fit The retrofit market has many possible applications for the CBSF. The CBSF can be installed by replacing an existing catch basin without having to "chase the grade," thus reducing the high cost of re- piping the storm system. ©2006 CONTECH Stormwaler Solutions Toll-free'. 800.5x8 x661 1 of 3 con[ecM1Slormwaleccom CalcM1eesin SlormFlller Operellon entl Malnlenanca GUldellnes Maintenance Guidelines Maintenance procedures for typical catch basins can be applied to the Catch Basin Storm Filter (CBSF). The filter cartridges contained in the CBSF are easily removed and replaced during maintenance activities according to the following guidelines. 1. Establish a safe working area as per typical catch basin service activity. 2. Remove steel grate and diamond plate cover (weight = 100 lbs. each). 3. Turn cartridge(s) counter-clockwise to disconnect from pipe manifold. 4. Remove 4" center cap from cartridge and replace with lifting cap. 5. Remove cartridge(s) from catch basin by hand or with vactor truck boom. 6. Remove accumulated sediment via vactor truck (min. clearance 13" x 24"). 7. Remove accumulated sediment from cartridge bay. (min. clearance 9.25" x 11") 8. Rinse interior of both bays and vactor remaining water and sediment. 9. Install fresh cartridge(s) threading clockwise to pipe manifold. 10. Replace cover and grate. 11. Return original cartridges to CONTECH Stormwater Solutions for cleaning and media disposal. Media may be removed from the filter cartridges using the vactor truck before the cartridges are removed from the catch basin structure. Empty cartridges can be easily removed from the catch basin structure by hand. Empty cartridges should be reassembled and returned to CONTECH Stormwater Solutions, as appropriate. Materials required include a lifting cap, vactor truck, and fresh filter cartridges. Contact CONTECH Stormwater Solutions for specifications and availability of the liking cap. The vactor truck must be equipped with a hose capable of reaching areas of restricted clearance. The owner may refresh spent cartridges. Refreshed cartridges are also available from CONTECH Stormwater Solutions on an exchange basis. Contact the maintenance department of CONTECH Stormwater Solutions at (503) 240-3393 for more information. Maintenance is estimated at 26 minutes of site time. For units with more than one cartridge, add approximately 5 minutes for each additional cartridge. Add travel time as required. ©2666 CONTECH Stormwater Solutions Toll-free'. 800548.466] 2of3 contecM1Stormwater com CatchBasln StormFilter Operation antl Maintenance GUitlelines Mosquito Abatement In certain areas of the United States, mosquito abatement is desirable to reduce the incidence of vectors. In BMPs with standing water, which could provide mosquito breeding habitat, certain abatement measures can be taken. 1. Periodic observation of the standing water to determine if the facility is harboring mosquito larvae. 2. Regular catch basin maintenance 3. Use of larvicides containing Bacillus thuringiensis israelensis (BTI). BTI is a bacterium toxic to mosquito and black fly larvae. In some cases, the presence of petroleum hydrocarbons may interrupt the mosquito growth cycle. Using Larvicides in the Ca[ch8asin Storm Filter Larvicides should be used according to manufacturer's recommendations. Two widely available products are Mosquito Dunks and Summit B.t.i. Briquets. For more information, visit httpa/wwwsu m m itchemicaLcom/mos_ctrlld efault.htm. The larvicide must be in contact with the permanent pool. The larvicide should also be fastened to the Catch Basin StormFilter by string or wire to prevent displacement by high flows. A magnet can be used with a steel catch basin. For more information on mosquito abatement in stormwater BMPS, refer to the following: http://www. ucmrp. ucdavis.edu/publications/ m a n a g i n g m o s q u i toe s st o r m wale r8125. pd f ©2006 CONTECH stormwater Solutions Toll-free'. 600 548 466] 3 of 3 contecMtormwater mm CatcM1Basn SlormFil~er Operation anE Maintenance Guitlelines Attachment "D" Stormtech~ Maintenance Manual S~tormTech~ Oe(erbnn ~Re(en0on ~keJiar9r Subsurface Storrnwater ManaaemenC" StormTech~ Chamber System for Stormwater Management lsolatorT" Row 0&M Manual 1.1 INTRODDCiION An Important component of any Stormwater Pollution Prevention Plan is inspection and maintenance /he StormTech Isolator Row is e paten) pending technique to inexpensively enhance Total Suspended Solids (TSS) removal and provide easy access for inspection and maintenance. 1.2 THE ISOLATOR" ROW The Isolator Raw is a row of StormTech chambers, either SC-740 or SC-310 motlels, that is surrounded with filter fabric and connected to a closely located manhole for easy access. The fabric-wrappetl chambers provide for settling antl filtration of setliment as storm water uses in the Isolator Row antl ulfimately passes through the filter fabric. The open bovom chambers antl perforated side- walk allow storm water to flow both vertically antl horrzon- telly out of the chambers. Sediments are captured in the Isolator Row protecting the storage areas of the atlja- cent stone and chambers from sediment accumulation. Two different fabrics are used for the Isolator Row. A woven geotextile fabric is placed between the stone antl the Isolator Row chambers. The tough geotextile provides a metlia for storm water filtration antl provides a durable surface for maintenance operations. It is also designed to prevent scour of the underlying stone and remain intact during high pressure jetting. Anon-woven fabric is placed over the chambers to provitle a filter media for flows passing through the pertora0ons in the sidewall of the chamber. The Isolator Row is typically designed to capWre the "first flush" and offers [he versatility to be sized on a vol- ume basis or flaw rate basis. An upstream manhole not only provides access Io the Isolator Raw but typically Includes a high flow weir such that storm water flowra[es or volumes that excnod the capacity of the Isolator Row overtop the over flow weir and discharge through a maniloW to the other chambers. The Isolator Row may also be pan of a treatment train. By treating storm water prior ro entry inb the chamber system, the service life can be extended and pollutants such as hydrocarbons can be capWred. Pre-treatment best management practices can 6e as simple as tleep sump catch basins, oil-water separators or can be lnno- votive storm water Veatment tlevices. The tlesign of the treahnent train antl selection of preVea[ment devices by the design engineer is open driven by regulatory requirements. Whether pretreatment is used or not, the Isolator Row Is recommended by StormTech as an effective means to minirnlze maintenance requirements and maintenance costs. Note: See the Storm tech Design Manual /or detailed inNrmation on designing inlets fora StormTech system, including the Isolator How StormTech Isolator Row with Overtlow Spillway (not to scale) OPTIONAL PFlE-lnEA1 MEN1 STOFlMiECH ' ISOLATOR ROW MANHOLE wITR ovEREEOw wEIR HEADER ~ ~ rr,r ~ >ro ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ r~ ~ ~ OPTIONAL ACCESS /// ~eTORMTEGH CHAMBEflR 2 Call StormTech at 888.892.2890 or vi511 our website at wwwstormtech.tom for technical and protluct iMOrmabon. Looking down the Isolator ROw from the manhole opening, woven geote#ile is shown between the chamber and stone base. StormTech- 2.1 INSPECTION The frequency of Inspection and Maintenance varies by location. A routine inspection schedule needs to be established for each individual location based upon site specific, variables. The type of land use (ia. industrial, commercial residential). anlicipalod pollutant load, per- cent imperviousness. climate, etc. ell play a critical role in determining [he aGUal frequency of inspection and maintenanro practices. AI a minimum, StormTech recommends annual inspec- tions Initially. the Isolator Row shoultl be inapecled every 6 months for the first year of oporation. For subsequent years, the inspection should be adlusled based upon previous observation of sediment deposilioo_ The Isolator Now ineorporatss a combination of standard manhole(s) and strategically located inspection ports (as neetletl). The inspection ports allow for easy access to the system fmm the surface, eliminatlng the need ro perform a confined space entry far inspection purposes. If upon visual inspection it is found that sediment has accumulated, a stadia and should be inserted to deter- mine the depth of 5edimenL Whon the average depth of sediment exceeds 3 inches Throughout the length of the Isolator Row, clean-out should be performed. 2.2 MAINTENANCE The Isolator Row was designed to reduce the cost of periodic maintenance. By "isolating" sediments to just one row, costs are dramatically reduced by eliminafing the need to clean out each row of the entire storage bed. If inspection indicates the potential need for main- tenance, access is provided via a manhole(s) located on the end(s) of the row for cleanoul. If entry into the manhole is required, please follow local and OSHA rules for e confined space en Vies. Examples of culvert cleaning nozzles appropriate for Isolator Fow maintenance. (These are not StormTech products.) Maintenance is accomplished with the JetVac process. The JetVac process utilizes a high pressure water noa zle to propel itself down the Isolator Row while scouring and suspending sediments- As the nozzle is retrieved, the captured pollutants are flushed back into the man- hole for vacuuming- Most sewer and pipe maintenance companies have vacuum/JetVac combination vehicles. Selection of an appropriate JetVac nozzle will improve maimenance efficiency Fixed nozzles designed for cul- verts or large diameter pipe cleaning are preferable. Rear facing jete with an effective spread of at least 46" are best Most JetVac reels have 400 feet of hose allow- ing maiNenance of an Isolator Row up to 50 chambers long The JetVac process shall only be pertormed on StormTech Isolator Rows that have AASHTO class 1 woven geotextile (as specifietl by StormTech) over their angular base stone. StormTech Isolator Row (not to scale) -12'MIN ID 25'MAX OD PIPE INSPECTION PORT sET 15' FROM BOTTOM LOCATION PER OF CHAMBER ENGINEER'S DRAWI CATCH BASIN OR COVER ENTIRE ROW WITH AASHTO M2B9-I CLAS52 NONWOVEN GEOTEXTILE I SG]00-a'WIDE GTRIP rSTORM~ BC 310-5'WIOE STRIP I ENDCAP WOVEN GEOTE)(TILE THAT MEETS MSHiO M2B8 GIASS 1 REQUIREMENTS, BETWEEN STONE BARE AND CHAMBERS SG-]4a-B'E' WIDE STRIP SC31n-6' WIDE STRIP Call StormTech a1888.892.2694 or visit our website at wwwstormtech.com for technical and product information. 3 Step 1~ Insperl Isolator Row for sediment StormTech Isolator Row (not to scale) A) Inspection ports (il present) i7 Remove lid from floor box frame Remove cap from 'mspectlon riser ui. Using a flashlight and stadia rod. measure depth of sediment and record results on maintenance log. iv If sediment is aL or above. 3 inch depth proceed to Step 2 If not a proceed to step 3. 8) All Isolator Rows i Remove cover from manhole at upstream antl of Isolator Row ii. Using a flashlight inspect down Isolator Row through outlet pipe 1. Mirrors on poles or camerae may be used to avoid a confined space entry 2-Follow OSHA regulations' for confined space entry If entering manhole iii. I( sediment Is at or above the lower row of sidewall holes (approximately 3 7nchos) proceed to Slop 2. If not proceed to Step 3. Step 2) Clean out Isolator Row using the JetVac process A) A fined culvert cleaning nozzle with rear facing nozzle sproad of 45 inches or more is preferable B) Apply multiple passes of JetVac until backflush water is eloan C) Vacuum manhole sump as required Step 3~ Replace all caps, lids and covers, record observations and actions SI¢p G) Inspect & clean catch basins antl manholes upstream of the SlonnTech system Sample Maintenance Log 3/15/01 63 k. none ~ Ne installation F ed~mtie Cl frame at grade dtm _ 9124/01 - 62 O1 fe - 5omeg It felt em __ ~ /20/03 _ 58 OSfC _ Mucry feel deb s ebl nmanhole and n rv _ _ _ _ Ito ow, ma v a due _ 9/1/03 63 h. 0 y tam I tad d ac u ed dim StormTech® De~ention•Re(enfion•Recharge Subsurface Stormwater Management' 20 Beaver poaq Suite 104 WeUersfield Connecticut 106709 860.529.0188 1 888 892 2694 fax Bfi6.328.8401 ~ wwnstormtech.com Sro rmTech products are coveP tl by one or mar of Iha following palen6: U.S. Patents: 5,401,459', 5,511,903 5,716,163; 5,5867 8', 5,839,844', Canadian Palenls: 2,158,418 Other U.S. antl Foreign Patents Pending Printed in US.A. ©Copyright. All rights reserved. StormTech LLC, 2004 5090104-t StormTech° 13.1 TREATMENT TRAIN INSPECTION AND MAINTENANCE 1 he Storrnloch recommended treatment train Inlet system has Three tiers of treatment upstream of the Storm loch chambers. II is rrcornmended that inspection end main tenanco Q&M) be initiated at the lurthest up imam treat- ment tier and continue downstream as necossal y. I he fallowing I&M procedures follow this approach providing I&M intonnalion in the following order I Ter 1 Pretrealmenl (RMP}, l~ier2-StorrnTech Isolator Row, and lier3 Eccemric Pipe Header System- 13.2 CATCHBASIN/MANHOLE 18M Typically a s[ormwaler system will have catchbasins and manholes upstream of the detent'ron/retention sys- tem. In same cases these may be the only pre-treatment devices. Regular I&M of catchbasins and manholes should be scheduled end performed as part of a sites routine maintenance plan. Catchbasin/Manhole -Step-by-Step Maintenance Procedures 1) Inspect catch basins and manholes upstream of StorrcrTech chambers for sediment 2) Remove grate or cover 3) Skim off oils and Hoatables 4) Using a stadia rod, measure the depth of sediment 5) If sediment is at a depth greater than 6" proceed to slap fi. II not proceed to step Z 6) Vacuum or manually remove sediment 7) Replace grate 8) Record depth & date and schedule next inspection Figure 18-Catchhasin/Manhole 18M Steps -z.r ~~ y~rtn d 4,56 Iy_ t . \,__~ ~~ 13.3 PRE-TREATMENT DEVICE 18M Manufacturer's I&M procedures should be followed for proprietary pretreatment devices such as baffle boxes, swirl concentrators, oil-water separators, and filtration units. Tahle 10 provides some general guidelines but is not a substitute for a manufecWrers specific insirucoons- TABLE 10- Pretmatment Inspection and Maintenance Cultlelinas ]{f'I '~iai®M.1 6! nl@t ~b -4~~`.:~~o ~ti • t 91 - ®iI L111YC~7t:[t[11 ~ Stormiech IsolatorTM Row ~' _ Bi-Annually _JefVac -Culvert Cleaning Noule Preferred Sediment Basin L. __. - ____. ' Duarterly or after large storm evens Excavate setllmenl ', Catch Basin Sump Duarterly Excavate pump, or vacuum Setlimenlation SlrucWre Duarterly Excavate pump. or vacuum Catch Basin Filer Bags -. Alter all storm events Clean and/or replace filler bags Porous Pavement Duarterly Sweep Pavement I Pipe Header Design _ Duarterly Excavate pump or vacuum Water Duality Inlet T Duaderly ~, Excavate, pump, or vacuum Sand Filters _- '~ Duarterly or after storm even) Remove8 replace sand filler 'This schedule does not account for regional o r site vanables Local municipal guidelines should be /allowed /or inspection when available. "The methods stated are minimum guidelines for removal and cleaning of system. Other methods may apply Call S1ormTech at 860.529.8188 or 888.892.2694 or vs t our websi[e at wwwstormtech cam for technical and product informal en 21 13.4 ISOLATORT"' ROW INSPECTION Regular inspection and maintenance are essential To assure a properly functioning sTOnnwaler sysTom. Inspection is easily accomplished Through the manhole or optional Inspection ports of an Isolator Row_ Please follow local and OSHA rules for a donflned space entry. Inspechon ports can allow inspection to be accomplished completely from The surface without the need fore con- fined space envy Inspection ports provide visual access to The system with the use of e Ilashlig M. A stadia rod may be inserted To determine the depth of sediment. If upon visual inspection it is lound that sedlmen[ has accumulated to an average depth exceeding 3' (76 mm), cleanout is required. A StormTech Isolator Row should initially be inspected immediately after completion of the site's construction- While ovary ellorl should be made to prevent sedircienT from entering the system during construction, I[ is during this time that excess amounts of sediments are most likely to enter any stormwater system. Inspection and maintenance, if necessary. should be performed prior fo passing responsibility over fo The sites owner. Once in normal service, a StormTech Isolator Row should be inspected bi-annually un61 an understzntling of the slTes characteristics is developed. The site's maintenanoe manager can Then revise the inspection schedule based on experience or local requirements 13.5 ISOLATOR ROW MAINTENANCE JetVac maintenance is required it sediment has been col- lected b an average depth of 3" (76 mm) or more inside the Isolator Row. The JetVac process utilizes a high pressure water nozzle to propel itself down the Isolator Row while scouring antl suspending sediments. As the nozzle is retrieved, a wave of suspended sediments is flushed back into the manhole for vacuuming. Most sewer and pipe maintenance companies have vacuum/ JetVac combination vehicles Fixed nozzles designed for culverts or large diameter pipe cleaning are preferable. Rear facing jets with an effective spread of at least 45" (1140 mm) are best. Mast JetVac reels have e mini- mum of 400 feet (122 m) of hose allowing maintenance of an Isolator Row up to 50 chambers long. The JetVac process shall only be performed on StormTech Rows that have AASHTO class 1 woven geotextile over (heir angular base stone. T" Examples o/culvert cleaning nozzles appropriate for Isolator Fow maintenance. (These are not StormTech protlucis.) 22 Gall SmrmTech aT 860.529.8188 or 888.892.2690 or visit our website aT wwwstorm[ecM1.oom for teennlcal and pronuU mformaoon. Atypical JetVac track (IDis is not a StormTech product) StormTech° STORMTECH ISOLATOR'" ROW - STfP-BY-STEP MAINTENANCE PROCEDURES Step 11 Inspect Isolator Row for sediment AJ Inspection parts (il present) i. Removo pd from floor box frame ii Romove cap from inspection riser lii_ Using a Ilashlight antl stadia rod, measure depth of sediment iv. II sediment is at, or above, 3" QFi mm) depth proceed to Sfep 2 If not proceed to step 3. U) All Isolator Rows i. Remove cover from manhole at upstream end of Isolator Row ii. Using e flashlight inspod down Isolaror Row through outlet pipe L Mirrors on poles or cameras may be used to avoid a confined space entry 2 Follow OSHA regulations for confined space entry if entering manhole iii_ II s'edimeni is at or abovo the lower row of sidowall holes [approximately 3" p6 rnm)] proceed to Step 2. II not proceed to Step 3. Step 2) Clean out Isolamr Row using the JetVac process A) A fined culvert cleaning nozzle with rear faring nozzle spread of 45' (1140 rnm) or more is preferable B) Apply multiple passes of JetVac until backflush water is clean C) Vacuum manhole sump as required Step 3) Replace all caps, lids and covers Step 4) Inspect and clean catch basins and manholes upstream of the StormTech system follovnng the procedures for Classic Manifold Inlet System Call StormTech at 860.529.B1B8 or 666 692.2694 or v sit our website at wwwstormtech com for technical antl product information. 23 Figure 19 StormTech Isolator Row (not to scale) 13.6 ECCENTRIC PIPE HEADER INSPECTION Theses yutdelines do not supercede a pipe manufac- turer's recommended I&M procedures. Cansuli with the manufacturer of the pipe header system for speatic I&M procedures. Inspection of the header system should be carried out quarterly. On sites which gonoraie higher levels of sediment more frequent inspections may he necessary. Headers may be accessed through risers, access ports or manholes. Measurement of sediment may be taken with a stadia rotl or similar device. Clean- aW of sediment should occur when the sediment volume has reduced the storage area by 25% or the depth of sediment has reached approximately 25% of iho diameter of the structure. 13.1 ECCENTRIC PIPE HEADER MAINTENANCE Cleanout of accumulated material shoultl be accom- plishetl by vacuum pumping the material from the head- er Cleanout should be accomplished during dry weath- er Care should be taken b avoid flushing sediments out Through the outlet pipes and into the chamber rows. Eccentric Heatler Step-by-Step Maintenance Procedures 7. Locale manholes, access pons or risers connected m the header syffiem ?. Remove grates or rovers 8. Using a stadia rod, measure the depth of sediment h. If sediment Is at a depth of about 75% pipe volume or 25 % pipe diameter proceed to step S. If not proread to siep 6. 5. Vacuum pump the sediment Do not flush sediment oW inlet pipes. 6. Replace grates and covers 7. Record depth antl date and schedule next inspection Figure 20 - Eccentric Manifoltl Maintenance a, a, s 24 Call StormTech al 860.529.8188 or 888.892.2694 or visit our wehsite at wwws[ormtech.com for technical and protluc~ inlorma[ion.