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Home My WebLink AboutStormwater, Erosion, and Sediment Control - PLN General - 6/23/2004 RECEIVED OUN 2 , 2004 STORMWATER 426 W. CEDAR ST. and EROSION and SEDIMENT CONTROL SITE PLAN for j 1�583 138-1 E Shelton Springs Road Shelton, Washington 98584 Located in Tract 10 of the NE 1/4 of the NW V4 of Section 129 T20N, R4W,W.M. Prepared for: Ray Allen 1901 Parkwood Dr. Olympia,WA 98501 360-943-7722 Prepared by MARLEY L.YOUNG,CONSULTING ENGINEER P.O.Bog 1343 Shelton WA 98584 (360) 426-7475 Project No. 99-28 April 18,2000 ro az-66 a3 sn9m��ano�"I�t�i SNOLLV'MIIVD madoddfIS SZ.NLqL1iHJV.L.LV �I ......................................................................................................................... uolisog. 0 s,laolustu £I .............................................................................................................................. su0141PuoO FIO £T-Zi ......................................................................................... 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Prepared for: Ray Allen 1901 Parkwood Dr. Olympia,WA 98501 360-943-7722 NEED AND PURPOSE The Puget Sound Water Quality Management Plan(PSWQMP)which is administered by the State of Washington Department of Ecology mandates that all counties and cities within the Puget Sound drainage basin adopt ordinances to control runoff from new development and redevelopments. The PSWQMP also directs local governments to adopt stormwater programs which must include minimum requirements that are consistent with the PSWQMP,and which are substantially equivalent to the DOE's Stormwater Management Manual for the Puget Sound Basin, (DOE's Technical Manual). The goal of the Puget Sound Water Quality Management Plan is to: ► Protect and restore beneficial uses of aquatic resources,including shellfish beds,fish habitat,and other resources; ► Prevent contamination of sediments from urban runoff; ► Meet standards for water and sediment quality by reducing pollutant discharges from stormwater throughout Puget Sound. BEST MANAGEMENT PRACTICES(BMPs) Best management practices(BMPs)are defined as physical,structural,or management practices that, when used singly or in combination,prevent or reduce pollution of water. Specific BMPs have been developed by Ecology to control stormwater runoff(quality and quantity)for protection of receiving waters. Marley L.Young Consulting Engineer Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. There are three main reasons for applying BMPs before considering advanced treatment. First,it has been shown through research and experience that BMPs can significantly reduce pollutants in stormwater.Using BMPs to control localized discharges is cost effective in comparison to treating large volumes of water. ,Second, our lakes and streams depend on stormwater to provide adequate flow for fish habitat and water quality. Our groundwater resources also depend on stormwater for recharge. BMP implementation offers a way to discharge water back into the natural system. Third,and perhaps most important,stormwater management programs demand the conscientious use of best management practices to protect water quality. Specific BMPs that cover stormwater runoff quality and quantity have been included in Ecology's Technical Manual. Those BMPs can be divided into three basic categories,including Source Control BMPs,Runoff Treatment BMPs and Streambank Erosion Control BMPs. Source Control BMPs are designed to prevent pollutants from entering stormwater by eliminating the source of pollution or by preventing contact of pollutants with rainfall and runoff. Source controls are usually the most cost-effective because they reduce or eliminate the need for treatment BMPs. Implementing source control BMPs generally involves relatively simple and straightforward actions. Examples of source control BMPs include erosion control(e.g., covering disturbed soil), covering material storage areas,and eliminating illicit discharges. Runoff Treatment BMPs are designed to remove pollutants contained in stormwater runoff. These types of BMPs are the second line of defense in protecting stormwater quality. Examples of runoff treatment BMPs include infiltration basins,biofiltration swales and sediment ponds. Streambank Erosion Control BMPs are designed to protect stream ecosystems from erosion and sedimentation. Types of streambank erosion control BMPs include flow attenuation BMPs for reducing peak flows from a development(e.g.,detention ponds,infiltration trenches), and streamside stabilization BMPs used to stabilize eroding streambanks. I, PROJECT OVERVIEW The proposal is to develop a site plan for light industrial development on an existing parcel of property containing 3.25 acres(per Mason County Assessor's records),located at 1381 E Shelton Springs Road. The total property lies south of Shelton Springs Road. Of the 3.25 acres, 1.95 acres are directly involved in land modification for light industrial development. The acreage not included in this development is the acreage lying southerly of the existing shop. Because of the upward slope of this ground,this area is not projected for improvement. The stormwater and erosion control requirements will focus on the 1.95 acres intended for modification. There will be one access from Shelton Springs Road. For stormwater runoff design purposes we are analyzing the access road, future parking,and future building(s)sites as if they were impervious, either roof or asphalt surfacing. For example,the ground around any future building for design purposes will be asphalt for parking and material storage. Marley L.Young Consulting Engineer 2 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. Part of the existing house roof and all of the existing shop roof are tightlined to infiltration pond A-A. In order to satisfy the treatment requirement for motor oils,etc.,that may be dripped onto the shop floor, we have designed it as follows: the shop floor and the concrete parking pad in front of the shop drain to a spilt control separator and then gravity flow to a wet well with a submersible pump that pumps the stormwater to a bioswale draining into infiltration pond A-A. We feel that the combination of spill control separator and bioswale satisfies treatment required for the use of the shop. The runoff from the access road north of the infiltration ponds(6,025 square feet)and the future parking (9,872 sf)is intended to be directed into a bioswale adjacent to pond B-B. It is expected that the bioswale will provide adequate treatment for the future parking and access road. The future building(s)site(19,816 sf)is also considered as impervious area,8,000 sf of building and 11,816 sf of paved storage. The stormwater runoff from the building roofs will be piped directly to the infiltration pond A-A. The paved areas around the building will be contoured and directed to the bioswale A-A. The area reserved for septic tanks and drain fields(9,320 sf)is contoured to discharge into the infiltration pond A-A. Minimum Requirements The calculated total of impervious acreage is 1.15 acres. The project is designed to include a 15-foot wide buffer along the easterly property line adjacent to the proposed road and a 7.5-foot wide buffer along the westerly property line southerly to the hammerhead turnaround. The area that will be disturbed in developing this lot represents approximately 60 percent of the total. The impervious area represents 35 percent of the total. (The impervious area represents the existing house and shop and the future parking and building(s)site.) Mason County has adopted the Department of Ecology"Stormwater Management Manual for the Puget Sound Basin". This project is defined as a redevelopment. The project adds or creates more than 5,000 square feet of impervious area, and disturbs more than one acre of land. Therefore,this project is required to comply with the Large Parcel Minimum Requirements#1 through#I I found in Section I-2.5 of the Department of Ecology's Stormwater Management Manual for the Puget Sound Basin(the Technical Manual). This Stormwater Site Plan consists of a Large Parcel Erosion and Sediment Control Plan and a Permanent Stormwater Quality Control(PSQC)Plan. This report is intended to be a part of said Plan. The project shall comply with Redevelopment Minimum Requirements#1 through#11. Minimum Requirement#1: EROSION AND SEDIMENT CONTROL See Section IX, Erosion and Sediment Control Plan(Requirements 1-IS),for the Large Parcel Erosion and Sediment Control Plan for this project Minimum Requirement#2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS • Natural drainage patterns shall be maintained,and discharges from the site shall occur at the natural location,to the maximum extent practicable. No surface water drainage flows through this project. Marley L.Young Consulting Engineer 3 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. Minimum Requirement#3: SOURCE CONTROL OF POLLUTION Potential pollution from stored motor oils, brake fluid etc., will be housed in a small building which will have a concrete floor constructed in conformance with DOE Manual Fig.IV-4.9, Covered and Bermed Containment A rea,page IV-4-12. Also, see page 2 of 2 of Engineer's Civil Drawings. Roof drainage shall be collected and directed to the infiltration ponce Stormwater from all pavement shall be directed through a bioswale, then into an infiltration pond Minimum Requirement#4: RUNOFF TREATMENT BMPS All stormwater runoff is discharged to infiltration trenches. All storm events equal to or less than 100 year storms are designed to stay on site. The DOE Technical Manual, Page IV-1-6, states, "Stormwater Treatment is not required for Parking Lots with less than 20 stalls, except for a simple oil spill control separator(BMP RO-05 in Volume EEE, Runoff Control), unless it is a retail business that experiences a high turnover of vehicles." Minimum Requirement#5: STREAMBANK EROSION CONTROL N/A-No stormwater runoff is discharged offsite or directly to a stream. Minimum Requirement#6: WETLANDS N/A-This property does not include wetlands. Minimum Requirement#7: WATER QUALITY SENSITIVE AREAS Mason County has designated this area as an Aquifer Recharge Area. Minimum Requirement#8: OFF-SITE ANALYSIS AND MITIGATION N/A -The calculated discharge for the I00 year storm and less is irjdtrated on site. Further analysis is not required. Minimum Requirement#9: BASIN PLANNING • An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. N/A-No basin plan is in place. Minimum Requirement#10: OPERATION AND MAINTENANCE • An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs,and the party(or parties)responsible for maintenance and operation shall be identified. The private facility maintenance checklist should be tailored to the facility. The owner(s)will be responsible for operation and maintenance of the stormwater facilities. Mason County requires that a Declaration of Covenants Associated with Privately Maintained Storm Drainage Facilities be executed and filed with Mason County as part of the approval process. A core is s attached Minimum Requirement#11: FINANCIAL LIABILITY • Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. NotApplicable. II PLOT PLAN A plot plan(Engineer's Civil Drawing) has been developed for the project, showing the supposed footprint of the area of the buildings,the footprint of paved parking,the location of the buffer strips and infiltration ponds, and the layout of the proposed access. The drawings are attached as part of this Stormwater and Erosion Control Site Plan. Marley L.Young Consulting Engineer 4 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. III PRELIMINARY CONDITIONS SUMMARY The project is located in Tract 10 of the NE'/4 of the NW'/4 of Section 12,T20N,R4W,W.M. Shelton, Mason County,Washington;commonly known as 1381 E Shelton Springs Road, Shelton,Washington 98584;Parcel No.42012-21-00100. The property is located within the Urban Growth Boundary of Mason County. This property contains approximately(3.25 acres). The lot has 223 feet of frontage along Shelton Springs Road. There is an existing three bedroom residence and a shop building on the site. Current access into the property is by an existing driveway from Shelton Springs Road. This access is intended to be abandoned. I_V OFF-SITE ANALYSIS (No off-site analysis is required. The calculated 100 year storm event is being disposed of on site.) Wetlands or Water of the State This site is not within 200 feet of any waters of the State. No wetlands have been identified. Analysis of the 100-year Flood This site does not contain or abut a Federal Emergency Management Administration(FEMA)identified stream and is,therefore, outside any 100-year flood plain. V PERMANENT STORMWATER QUALITY CONTROL PLAN Analysis and design of proposed stormwater runoff control facilities,including treatment and source control BMPs. Calculation of Areas and CN#s Description CN# Pond A-A(sfl Bioswale A-A(so. Pond B-B(sfl Bioswale B-B(s) '/2 Existing house 98 900 Shop 98 1198 Concrete slab(24'x26') 98 624 624 Access south of pond 98 5000 Access north of pond 98 8240 6025 Future building sites 98 19816 7926 Future parking 98 98 9872 Square feet 27536 8550 18112 15897 Acres 0.632 0.196 0.416 0.365 SF=1.1 Acres 0.695 0.216 0.457 0.401 Easterly buffer 77 3000 3000 Area west of shop 77 10220 Square feet 10220 3000 3000 Acres 0.235 0.069 0.069 SF=1.1 0.258 0.076 0.076 Marley L.Young Consulting Engineer 5 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. Description CN# Pond A-A(sfl Bioswale A-A(sfl nl'o d B-B(sfl Bioswale B-B(sfl Pond area 68 5200 990 3400 990 Future drain field &buffer 68 9320 Square feet 14520 990 3400 990 Acres 0.333 0.023 0.078 0.023 SF=1.1 0.367 0.025 0.086 0.025 Pond 1 Composite CN Pond 2 Composite CN 77 0.258 19.872 77 0.076 5,833 68 0.367 a.933 68 0.085 5,838 Composite CN 71.72 0.625 44,806 72.22 0.162 11.672 Bioswale 2 Composite CN 77 0.076 5.833 68 0,025 1.700 Composit CN 74.77 0.101 7.533 SWC Acreages and CN#s to be used to Calculate Peak Discharge of Storm Events Pond 1 CN 71.72 98 Pond 2 CN 72.22 98 Acreage 0.625 0,700 Area 0.162 0.457 Bio 1 CN 68 98 Bio 2 CN 74.77 98 Acreage 0.025 0.216 Area 0.101 0.401 STORM EVENT DESIGN ASSUMPTIONS Based on DOE's Stormwater Management Manual: STORM EVENT ■ Rain Precipitation(in.) ■ Six-month,24-hour Storm Event 2.56" ■ Two-year, 24-hour Storm Event 4.00 ■ Ten-year,24 hour Storm Event 5.50 ■ Hundred year,24-hour Storm Event 8.50 ■ Rainfall choice IA ■ Hydrograph SBUH** ** Santa Barbara Urban Hydro,graph method DRAINAGE BASIN ■ (Gh)Grove Gravelly Sandy Loam 0-5% ■ Hydrologic Soil Group A ■ Infiltration Rate 6 min/inch or 10 inches/hr ■ Preexisting Conditions(because total discharge is on Site) N/A ■ CN#for Impervious Pavement&Roofs 98 ■ CN#for Landscaping,grass cover 50-75% 77 ■ CN#for Lawn,good condition, grass cover>75% 68 Marley L.Young Consulting Engineer 6 Project No.99-28 8Z'66'oN 1-!OJd L =U!Oua RUMU OD Sunk•I sol-W sd3 OZ'I =,CltoolaA 6-9 ulnuuod£I-9-III'gd`Imut'W 210Q 8ucsn • 90 0 (u)IuaroljaoD ssoug2nog s,Sutulm $/$ZO'O- ado1S ap msotg umut!"W • OZ'0 Iaad T y;daQ zalgM aleensotg umuT"W I:£ :sadols apis 0 goui/uilu- alux uousulgui • 1 _ :xpdaQ u!n • £ - UPPM.00H umummu 08 :gl2ua7 a001d • :e1aa r i�uo!ptulsuoj 91 n+s ig OL69 99£ty 6b0£ Z17LI 30- 3um1OA Isod • Itr'O 9Z'0 8I'0 11*0 s3a- MOH Isod • zff5T--o pi is—ax--UOJL aga -o u t -9 Juana mao;S •a;is uo pauculaz aq 1pm tAO1A Isod asmoaq paj!nbaa jou motd and :; aea uiao;S-jA-Oof a a ya i 0; u ! aQ V-V TIV SOig V199 9tZZ Stlol ZSZ 30- awntOA-PuOd • WE 09'I 98'0 VV0 )j- sipdaQ-Isod • 00'0 00'0 0000 OOOO 3o- aumIOA-IsOd ' 00*0 00'0 00'0 00'0 sp- Mo13-1Sod • au�IOIO �eaX=u4JL .i�nl q uom-9 jUaAa W.1 1S 52. 1Q y uaad,u 63 11.IuI ON (I:£)F39JaA 104 1eluozuog £ :sodolS op!S • 9 gouijunu- alug U0,99119W ' 'unu b 4- :glda(I ulw • SI 33- APPM J00H 'UTm 99 $' :q)Sua-I J00W • . aa; .1u 0663 u aool} y 1 ui g 1e loza J,u p 009Z£ £9I6I I I8ZI Z91L 30- aumloA IsOd • LI6'I 60I'I 6ZL'0 b6£'0 s3o- mO13lsod • .i a -00 a a -iay :a wa qluoui-9 jUaAa tUJOI .alis uo paun:Iai aq 1ptA enoU Isod asneoaq paimbat Iou mo13 aid V-V ClNod O.Lm saM] asIQ'TIV Z02LLNoJ HalvMLI ols-S,LTisau N!)Isaa *jjoutu aoejinsgns puu 3ou3ins Ieloi agl3o xoleo.pui ue sI(#ND)joQu,mN anima j1oun21 aqI`osfl PuL,I Pus adAs IToS `Iuang uuolS DIP uanFO UL -ml ssuuds U0113 is 3 I8EI`-Hv Auld Ray Allen.1381 E Shelton Springs Rd. DESIGN RESULTS-STORMWATER CONTROL ALL DISCHARGES INTO POND B-B Pre Flow not required because Post Flow will be retained on site. Storm Event 6_ month Two-year Ten-,year 100-vear ► Post Flow -cfs 0.244 0.414 0.599 0.980 > Post Volume -cf 4190 7100 10245 16705 Open Trapezoidal Basin with a floor area of 442 square feet: Floor Length: -ft 34 min. ► Floor Width: -ft 13 ► Min. Depth: -ft 4 min. ► Infiltration Rate -min/inch 6 ► Side Slopes: 3 Horizontal to 1 Vertical(3:1) No Infiltration Trench Discharge Storm Event 6-m n h Two-year Ten-year 10 Rear ► Post-Flow -cfs 0.00 0.00 0.00 0.00 ► Post-Volume -cf 0000 0000 0.00 0.00 ► Post-Depths -ft 0.48 1.11 1.77 2.90 ► Pond-Volume -cf 248 677 1293 - 2767 RIOSWALE B B Designed to Discharge the 100-Yr.Storm Event: Pre Flow not required because Post Flow will be retained on site. Storm Event 6-month Two-year Ten-year I O Rear ► Post Flow -cfs 0.21 0.36 0.51 0.82 ► Post Volume -cf 3485 6098 8712 13939 Bioswale Construction Criteria: ► Floor Length: -ft 65 minimum ► Floor Width: -ft 5 ► Min.Depth: -ft 1 ► Infiltration Rate -min/inch 0 ► Side Slopes: 3:1 Maximum Bioswale Water Depth in Feet 0.25 ► Maximum Bioswale Slope -0.02 fIlft ► Manning's Roughness Coefficient(n) 0.06 Using DOE Manual,Pg.III-6-13 Formula 6-9 Velocity= 1.39 fps VI SPECIAL REPORTS AND STUDIES N/A-No special reports or studies have been required or prepared for this project VI> BASIN AND COMMUNITY PLANNING N/A Marley L.Young Consulting Engineer 8 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. V_ IIa, PERNIITS A eg ncv Permit/Appr4val Mason County Environmental Permit Potential additional permits include: Mason County Grading Permit(if more than 50 yards of material are to be excavated, filled,and/or graded) Mason County Right of Way permit(if there is work in the right of way) IX EROSION and SEDIMENT CONTROL PLAN Project Description Proposed Light Industrial area development. Existing Site Conditions Single family residence occupying approximately 14,000 square feet. Approximately 75,400 square feet available for light industrial development. Condition of existing area to be developed is grass-covered undeveloped ground. Adjacent Areas Impacts N/A-Property to the west is existing light industrial. Property to the east is owned by a church and is part of the church operation. No impact anticipated. SCS Soils Description The Soil Conservation Service-Soil survey of Mason County Series 1951,No. 9,Issued September 1960, shows this property having soils type Grove gravelly sandy loam(Gh),0-5 percent slopes. The following description of Grove Series Soils was taken from the SCS Soil Survey ofMason County and Thurston County's SCS report. Soils conditions found on the property may not match exactly the soils described by SCS. Grove Series The Grove series consists of somewhat excessively drained,reddish-brown gravelly soils. It occupies the large glacial outwash plains. The Grove soils have developed from Vashon glacial drift,modified considerably by inclusions of local basaltic rock and mixed material from the Olympic Mountain glaciers. FROM TNURSTON couNrrs SCS UNDATED REPORT. THIS VERY DEEP, SOMEWHAT EXCESSIVELY DRAINED SOIL IS ON OUTWASH PLAINS. PERMEABILfTY IS RAPID IN THE GROVE SOIL. AVAILABLE WATER CAPACITY IS LOW. EFFECTIVE ROOTING DEPTH IS 60 INCHES OR MORE. RUNOFF IS SLOW AND THE HAZARD OF WATER EROSION IS SLIGHT. Grove gravelly sandy loam, O to S percent slopes(Gh)- This soil occupies nearly level outwash plains. In forested areas there is a 1-to 2-inch layer of needles, leaves,twigs,roots, and moss. The lower part is moderately decomposed and very dark grayish brown. The surface soil consists of reddish-brown,gravelly sandy loam,6 inches thick. It is very friable, is single grained,and contains a few small,round shot. The upper part of this layer contains a few firm, irregular,more reddish aggregates. The next layer extends to depths ranging from 12 to 14 inches. It is similar to the surface soil, except that it is more gravelly,contains less shot,and the gravel is stained and coated with dark reddish-brown fine material. Marley L.Young Consulting Engineer 9 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. The subsoil is a light-brown,very gravelly loamy sand. It is loose,is single grained,and contains no shot. At depths ranging from 24 to 32 inches,the subsoil grades to the substratum of loose gravel, cobbles, and sand. The dominant colors are gray,grayish brown,yellowish brown,and light brown. Much of the gravel is highly stained with nearly black and reddish-brown material. In places the upper 24 inches of the substratum is compact or weakly cemented. This soil is strongly to medium acid and less acid with depth. Surface runoff is very slow because of the rapid permeability of the soil and the smooth topography. .Use and suitability-Except for a very small acreage in farms producing mainly for the farm household,this soil is in forest,a use for which it is best suited. Because of droughtiness and low fertility, it is not suitable for hay or pasture. hi suitability,this soil is in classes 3 and 4 for Douglas-fir,partly because of the higher rainfall. Areas in young Douglas-fir are managed for Christmas trees. The soil is in capability subclass Vls. Critical Areas The area is designated by Mason County as a Critical Aquifer Area. Erosion and Sediment Control Measures Minimum Requirements Mason County has adopted the Department of Ecology"Stormwater Management Manual for the Puget Sound Basin", and this project must comply through implementation of a Large Parcel Erosion and Sediment Control Plan. All projects that disturb more than one acre must develop a Permanent Stormwater Quality Control Plan. (Mason County Ordinance 141-97). The fifteen large parcel minimum requirements specified by DOE are: EROSION AND SEDIMENT CONTROL REQUIREMENTS #1: Stabilization and Sediment Trapping • All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30,no exposed and unworked soils shall remain unstabilized for more than 2 days. From May 1 to September 30,no exposed and unworked soils shall remain unstabilized for more than 7 days. Prior to leaving the site,stormwater runoff shall pass through a sediment pond or sediment trap,or other appropriate BMPs. During construction the overburden which is approximately 3"in depth will be removed from the construction zone and stockpiled on site for use as cover at the conclusion of construction. Because of the gravelly sandy loam characteristics of this soil, migration during storm events is not expected to become a problem at this site. #2: Delineate Clearing and Easement Limits The majority of the 1.95 acres of property has been previously cleared and grubbed The delineation of clearing limits is identified as the property boundaries of the area under consideration for development. #3: Protection of Adjacent Properties The gravelly underlying soils have very little potential for migration. Protecting adjacent property from damage from sediment deposition does not appear to be a problem. Marley L.Young Consulting Engineer 10 Project No.99-28 Ray Allen,1381 E,Shelton Springs Rd. #4: Timing and Stabilization of Sediment Trapping Measures Although the gravelly characteristics of the soils do not encourage migration under the proposed action, during construction the detention/retention pond will act as a natural sediment pond and trap. #5: Cut and Fill Slopes Except for the ponds, all cuts and fills will not exceed two feet in height. Pond slopes will be no steeper than 3 foot horizontal to I foot vertical(3:1). #6: Controlling Off-site Erosion No stormwater discharge will leave this site. Therefore, off site erosion is not anticipated to become an issue. #7: Stabilization of Temporary Conveyance Channels and Outlets To prevent the possibility of erosion at the pond sites, quarry spalls should be placed where stormwater flows into the infiltration pond Quarry spalls sized D50=0.33. All other raw slopes will be seeded to grass. #S: Storm Drain Inlet Protection There is no public storm drainage system; however, the owner will take steps to protect the three catch basins which he is installingfor stormwater control and oil-water separation from being contaminated. #9: Underground Utility Construction Not Applicable to this project. #10: Construction Access Routes • Construction vehicle access shall be,whenever possible,limited to one route. Access points shall be stabilized to minimize the tracking of sediment onto public roads. There is one access to the site which will be surfaced with crushed rock. The gravelly soil found on this property is not sensitive to migration; therefore, stabilization of the construction access should not be an issue, and it is not anticipated that the accumulation of mud and debris onto the County road would become a problem. However, if accumulation does occur, the access to the property should be rocked with quarry spalls in order to prevent sediment migration off the site. 1 recommend that the access be surfaced with 1 %4"crushed rock #11: Removal of Temporary BMPs All temporary erosion and sediment control Best Management Practices (BMPs)will be removed when final site stabilization is achieved #12: Dewatering Construction Sites Dewatering is not necessary. During our soils investigation and percolation test attempts, we were unable to "stabilize"the soil, which means that the infiltration rate exceeded one minute per inch of drawdown. #13: Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediments that occur on-site during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14: Maintenance All temporary and permanent erosion and sediment control Bmps shall be maintained and repaired as needed to assure continued performance of their intended function. #15: Financial Liability Not Applicable to this project Marley L.Young consulting Engineer 11 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. Permanent Stabilization In addition to the stormwater infiltration ponds and bioswales,at the conclusion of site construction improvements,within seven days,permanent site stabilization shall be completed by spreading seed and mulch on all exposed soils to establish a ground cover. Stormwater Management Considerations Due to the porosity of the soils on this site,all of the stormwater runoff is being directed to an infiltration pond. It is anticipated that no stormwater will leave the property. Please see Section V,"Permanent Stormwater Quality Control Plan"for a complete description of the stormwater management plan. Maintenance The responsibility for maintaining the facilities will he with the owners of the property or their assigns. Calculations Calculations are briefly described in Section V above,and included in attached Calculations. Nonerosion and Sediment Control BMPs See Page 2 of 2 of the Civil Drawings. X. Bond Quantities Worksheet Retention/Detention Facility Summary Sheet and Sketch,and Declaration of Covenant Bond Quantities Worksheet-N/A Retention/Detention Facility Summary Sheet-N/A Declaration of Covenant- Mason County requires that a DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES be executed and filed with Mason County as part of the approval process. A copy is attached. XI MAINTENANCE&OPERATIONS MANUAL MAINTENANCE PLAN The responsibility for maintaining the facilities will lie with the owners of the property or their assigns (e.g.,Contractor). The facilities are designed to minimize the need for extensive maintenance. During construction the major maintenance activity is to inspect that the drainage flows toward the infiltration pond. If the drainage carries mud or debris,a silt fence and/or straw bales should be placed in the path of the drainage to reduce the amount of siltation into the pond. All erosion and sediment control BMPs installed shall be inspected regularly, especially after any large storm. Maintenance,including removal and proper disposal of sedi,-iie;nt should be done as necessary. (Generally sediment in the pond which restricts the infiltration must be removed.) Marley L.Young Consulting Engineer 12 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd. A spill control separator in a catch basin is installed in the concrete slab in front of the shop. This catch basin must be inspected and sediment removed from the bottom of the catch basin when it reaches a depth of 6 inches. Floating debris and oil should be removed annually in September. A wet well,located approximately 15 feet west of the spill control separator catch basin,is also a part of the oil-water separation design_ The wet well includes a submersible pump that pumps to bioswale A-A. The catch basin and pump should be inspected in September of each year and debris removed if necessary. Repair the pump if it is not functioning properly. The small catch basin at bioswale A A should also be inspected in September and all foreign objects removed. At the conclusion of site construction improvements,within seven days perrnanen site stabilization shall be completed by spreading seed and mulch on all exposed soils to establish a ground cover. TEMPORARY EROSION CONTROL Erosion control will be mitigated when necessary by the use of Filter Fabric Fencing,Straw and Hay Bale Barriers, and the Stabilization of the Construction Entrance. Please refer to the Attachments Fig.B2,B3, 114,B8,B9 and B16 for design proposals to satisfy the Large Parcel Requirements for the Erosion and Sediment Control Plan. CHANGED CONDITIONS The conclusions and recommendations in this report are based on my interpretation of site conditions, and the expectation that my on-site exploratory efforts adequately define the surface and sub-surface conditions throughout the site. In the event that the scope of the project or location of the improvements or surface/subsurface conditions differ from those I relied on in this report,I should be advised. At that time,a review of the changed conditions will be made and alternative or remedial recommendations given as requested. This Stormwater Site Plan has been prepared by: Q z � *v 'PSG/STER�� `yy� Marley L. Young P.E., S. Date `rd'�-Nit WIRES stsi a ATTACHMENTS SUPPORTING CALCULATIONS Marley L.Young Consulting Engineer 13 Project No.99-28 Ray Allen,1381 Shelton Springs Road,Shelton,WA MARLEY L. YOUNG CONSULTING ENGINEER Q P.O. BOX 1 343 SHEI..TON WA 98584 (3eO)42e-7475 Marley L. Young P.E., P.L.S., '.'Civil Engineering Civil Engineer& Land Surveyor Stornmter Site Plans Sewer Extensions o NIINIH PROJECT ENGINEER'S CERTIFICATTON I hereby certify that this Stormwater Site Plan prepared for Ray Allen has been prepared by me or under my supervision and meets minimum standards of Mason County and normal standards of engineering practice. I understand that the jurisdiction does not and will not assume liability for the sufficiency, suitability,or performance of drainage facilities designed by me. Y was U� Marley L. Young P.E.,P.L.S. Ln o N 14144 �� O IXPiRES 3/5/6 & } Marley L.Young Consulting Engineer 14 Project No.99-28 Ray Allen,1381 E Shelton Springs Rd ATTACHMENTS Marley L.Young Consulting Engineer Project No.99-28 RETURN ADDRESS GRANTOR(S)(Last,First and Middle Initial) RAY E. ALLEN ALLEN. RAY E. _ 1901 PARKWOOD DR. ALLEN.DOROTHY M. OLYMPIA, WA 98501 GRANTEE: MASON COUNTY DEPARTMENT OF PUBLIC WORKS DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES Declaration of Covenant In consideration of approval of the development known as Ray E. Allen, 1381 E. Shelton Springs Road, Shelton WA 98584,relating to real property legally described as follows: Tract 10 of the South 15 acres of the NE %a of the NW%of Section 12, Township 20 North, Range 4 West, W.M.,in Mason County,Washington. County Assessor's Property Tax Parcel Number 42012-21-00100 The undersigned, as owner(s), covenant and agree that: 1. If at any time Mason County reasonably determines that maintenance or repair work is required to be done to the existing, approved storm drainage facilities installed on the property described above and located outside of any public right-of-way(which will mean repair and or clean out of the existing system only to the same standards as originally installed and approved), the Director of the Department of Public Works shall give the current owners seven days notice that the County intends to perform such maintenance or repairs,or to have them performed by others. Tf the current owners have not completed or are not diligently pursuing the repair or maintenance of the system and it becomes necessary for Mason County to perform the work,the current owners will assume responsibility for the cost of such maintenance or repair and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments, and any costs or fees incurred by the County,should any legal action be required to collect such payments,will be borne by the parties responsible for said reimbursements. 2. If at any time Mason County reasonably determines that the existing and approved storm drainage system on the property poses a hazard to life and limb,or endangers property, or adversely affects the safety and operations of a public way, due to failure, damage or non-maintenance of the existing on-site storm system, and that the situation is so adverse as to preclude written notice to said owners, the Director of the Department of Public Works may take the measures necessary to eliminate the hazardous situation(which will mean repair or clean out of the existing system only to the same standards as originally installed and approved) provided the Director has first made a reasonable effort to locate said owner before acting. The current owners will assume responsibility for the cost of such maintenance or repair;and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments, and any costs or fees incurred by the County, should any be bome by the parties responsible for said reimbursements. 3. The owner shall keep the Mason County Public Works Department informed at all times as to the name, address and telephone number of the contact person responsible for the performance of maintenance or repair work to the storm drainage facilities. These covenants are intended to protect the value and desirability of the real property described above, and to benefit all the citizens of Mason County. They shall run with the land and be binding on all parties having or acquiring from the current owners or their successors,any right,title or interest therein, and to the benefit of all the citizens of Mason County. Signature Signature RAY E. ALLEN DOROTHY M.ALLEN Owner Owner 1901 Parkwood Dr. 1901 Parkwood Dr. Address Address Ol mpia_WA 98501 Olympia, WA 98501 City, State,Zip City, State,Zip Phone: 360-943-7722 Phone: 360-943-7722 - - -- --- - -,TATF QF-WASH) GT4N, ss. (INDIVIDUAL ACKNOWLEDGEMENT) County of MASON I, Notary Public in and for the State of Washington,residing at do hereby certify that on this day of 2000,personally appeared before me RAY E.ALLEN and DOROTHY M.ALLEN,husband and wife,to me known to be the individuals described in and who executed the within instrument and acknowledged that they signed and sealed the same as their free and voluntary act and deed for the uses and purposes herein mentioned. GIVEN UNDER MY-HAND AND OFFICIAL SEAL this day of. 2000. Notary Public in and for the State of Washington,residing at in said County. My Commission expires Ray Allen,1381 E Shelton Springs Rd. SUPPORTING T ,.,:-T: UALC:ULA�-n0 S Marley L.Young Consulting Engineer Project No.99-28 BIO SWALE CALCULATIONS POND #1 (A-1q Owner Ray Allen Project# 1 Remarks Bio Swale East Half-South of Sales Lot 2 Design for Swale Capacity 3 Date 04/10/00 4 8 Q for the max.year storm event to use the Swale 100 Year 9 Q= 0.41 cfs cubic feet per second y= 0.2 Max. Bio Swale water depth in feet 2.780794 s= 0.02 Slope of Bio Swale in feet per foot Z= 3 Swale side slope 3:1 Note: The free board above the storm event is double the 100-year event depth 5 (See Manual-III-6-19: SC-14.) 10 Use DOE Manual, page III-6-13 Formula(6-9) b=(Qn/(1.486)*(y^1.667)*(s^0.5)]-Zy Note-Assume Q is directed to both ends and CD is in middle. Q = 0.41 n = 0.06 (See Manning's Roughness Coefficients(n) IV Highway_ Channel and' Swales with Maintained Vegetation) 6 A. Depth of flow up to 0.7 feet: 7 1. Bermuda grass—Length 4 to 6 inches=n= .09 to.05; Use=0.06 Qn = 0.0246 (y^1.667) = 0.068362 (s"0.5) = 0.141421 (-Zy) _ -0.6 b = 1.112318 Swale has a maximum lenth of 80 ft. Swale must be widened to compensate for shorter length than 200'. — See Page I11-6-20, paragraph CO-1 200/ 80 x 1.112318 = 2.780794 feet design width 3 ft. use Flow Velocity Check v=Q/A - - -X=—Cross Sectional Area-=--ty+-Z"{y42}- - - - -------------— -- --- - ----- -- ----- -- - A= 0.342464 Therefore v= 1.197208 fps < 1.50 fls =OX BIO SWALE CALCULATIONS POND #2 Owner Ray Allen Project# 1 Remarks Bio Swale East Half-South of Sales Lot 2 Design for Swale Capacity 3 Date 04/17/00 4 8 Q for the max.year storm event to use the Swale 100 Year 9 Q= 0.82 cfs cubic feet per second y= 0.25 Max. Bio Swale water depth in feet 4.95641 s= 0.02 Slope of Bio Swale in feet per foot Z= 3 Swale side slope 3:1 . Note: The free board above the storm event is double the 100-year event depth 5 (See Manual-111-6-19: SC-14.) 10 Use DOE Manual, page 111-6-13 Formula(6-9) b=[Qn/(1.486)*(y^1.667)*(e0.5)]-Zy Note-Assume Q is directed to both ends and CD is in middle. Q = 0.82 n = 0.06 (See Manning's Roughness Coefficients(n) IV Highway Channel and Swales with Maintained Vegetation) 6 A. Depth of flow up to 0.7 feet: 7 1. Bermuda grass—Length 4 to 6 inches= n= .09 to.05; Use= 0.06 On = 0.0492 (y^1.667) = 0.099167 (s"0.5) = 0.141421 (-Zy) _ -0.75 b = 1.610833 Swale has a maximum lenth of 65 ft. Swale must be widened to compensate for shorter length than 200'. — See Page 111-6-20, paragraph CO-1 200/ 65 x 1.610833 = 4.95641 feet design width 5 ft. use Flow Velocity Check v= Q/A A=Cross Sectional Area= by+Z*(y^2) A= 0.590208 Therefore v= 1.38934 fps < 1.50 fts = O.K. 4/17/00 8 :33 :3 am Marley Young Engineer page 1 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 . 95 Acres Stormwater Control ------------------------- BASIN SUMMARY BASIN ID: la A-4 NAME: West Side Only 1/2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.33 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 .56 inches AREA. . : 0. 63 Acres 0.70 Acres TIME INTERVAL. . . . : 5. 00 min CN. . . . : 71.72 98 . 00 TC. . . . : 10 . 00 min 10. 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 .39 cfs VOL: 0 .16 Ac-ft TIME: 480 min BASIN ID: labio NAME: West Side Only 1/2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.25 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 .56 inches AREA. . : 0 .03 Acres 0.22 Acres TIME INTERVAL. . . . : 5 .00 min CN. . . . : 68 .00 98 . 00 TC. . . . : 10 . 00 min 10. 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE, n .11 rfc 17M. n nA Z�n_f+ mlrury nQn . T V V lm.L 11 BASIN ID: lb NAME: West Side Only 2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.33 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4.00 inches AREA. . : 0.63 Acres 0 .70 Acres TIME INTERVAL. . . . : 5 .00 min CN. . . . : 71.72 98 .00 TC. . . . : 10 . 00 min 10 . 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0.73 cfs VOL: 0.29 Ac-ft TIME: 480 min BASIN ID: Ibbio NAME: West Side Only 2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .25 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4.00 inches AREA. . : 0 .03 Acres 0 .22 Acres TIME INTERVAL. . . . . 5 . 00 min CN. . . . . 68 . 00 98 . 00 TC. . . . . 10.00 min 10.00 min ABSTRACTION COEFF: -0-20- - ----- - --- - PEAK RATE: 0.18 cfs VOL: 0 .07 Ac-ft TIME: 480 min 4/17/00 8 :33 :3 am Marley Young Engineer page 2 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control -- ---------------------- BASIN SUMMARY BASIN ID: lc A-A NAME: West Side Only 10 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.33 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 5.50 inches AREA. . : 0.63 Acres 0 .70 Acres TIME INTERVAL_ . . . : 5. 00 min CN. . . . : 71.72 98 . 00 TC. . . . : 10.00 min 10 . 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 1.11 cfs VOL: 0 .44 Ac-ft TIME: 480 min BASIN ID: lcbio NAME: West Side Only 10 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.25 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 5.50 inches AREA_ : 0. 03 Acres 0 .22 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 68 .00 98 . 00 TC. . . . :, 10. 00 min 10. 00 min ABSTRACTION COEFF: 0,20 PEAK RATE: 0 .26 cfs VOL: 0 .10 Ac-ft TIME: 480 min BASIN ID: id NAME: West Side Only 100 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.33 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 8.50 inches AREA. . : 0.63 Acres 0.70 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 71.72 98 .00 TC. . . . : 10 . 00 min 10. 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 1.92 cfs VOL: 0.75 Ac-ft TIME: 480 min BASIN ID: ldbio NAME: West Side Only 100 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.25 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE_ . _ . : TYPEIA PERV IMP PRECIPITATION. . . . : 8.50 inches AREA. . : 0 .03 Acres 0 .22 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 68.00 98.00 - ----- - --- - ------ - - TC. . . . : 10.Wmin I0.00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0 .41 cfs VOL: 0.16 Ac-ft TIME: 480 min 4/17/00 8 :33 :3 am Marley Young Engineer page 3 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control BASIN SUMMARY _ BASIN ID: 2a �3 _6 NAME: East Side Only 1/2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0. 62 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2.56 inches AREA. . : 0.16 Acres 0.46 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 72 .22 98 . 00 TC. . . . : 10 .00 min 10 .00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0 .24 cfs VOL: 0.10 Ac-ft TIME: 480 min BASIN ID: 2abio NAME: East Side Only 1/2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 .56 inches AREA. . : 0 .10 Acres 0 .40 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 74.77 98 .00 TC. . . .:, 10 . 00 min 10. 00 min ABSTRACTION C OR-vr- 0 ,2 0 PEAK RATE: 0 .21 cfs VOL: 0.08 Ac-ft TIME: 480 min BASIN ID: 2b NAME: East Side Only 2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.62 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : TYPEIA. PERV IMP PRECIPITATION. . . . : 4. 00 inches AREA. . : 0.16 Acres 0 .46 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 72 .20 98 .00 TC. . . . : 10 .00 min 10. 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0.41 cfs VOL: 0.16 Ac-ft TIME: 480 min BASIN ID: 2bbio NAME: East Side Only 2 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4 .00 inches AREA. . : 0 .10 Acres 0 .40 Acres TIME INTERVAL. . . . . 5.00 min CN. . . . . 74.77 98 .00 -- - - .- -1-a-.00- min 10 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 .36 cfs VOL: 0.14 Ac-ft TIME: 480 min 4/17/00 8 :33 :3 am Marley Young Engineer page 4 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control BASIN SUMMARY SUMMARY BASIN ID: 2c 6--e NAME: East Side Only 10 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0. 62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 5 .50 inches AREA. . : 0.16 Acres 0 .46 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 72.20 98. 00 TC. . . . : 10. 00 min 10 . 00 min ABSTRACTION COEFF: 0.20 PEAR RATE:- 0.60 cfs VOL: 0.24 Ac-ft TIME: 480 min BASIN ID: 2cbio NAME: East Side Only 10 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0.50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 5 .50 inches AREA. . : 0.10 Acres 0 .40 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . 74.77 98 . 00 TC. . . . :, 10 .00 min 10. 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0.51 cfs VOL: 0.20 Ac-ft TIME: 480 min BASIN ID: 2d NAME: East Side Only 100 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .62 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 8.50 inches AREA. . : 0.16 Acres 0 .46 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 72 .20 98 . 00 TC. . . . : 10 .00 min 10 . 00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0 .98 cfs VOL: 0 .38 Ac-ft TIME: 480 min BASIN ID: 2dbio NAME: East Side Only 100 year storm SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .50 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . .. : TYPEIA PERV IMP PRECIPITATION. . _ . : 8.50 inches AREA. . : 0.10 Acres 0 .40 Acres TIME INTERVAL. . . . . 5.00 min CN. . . . : 74.77 98.00 TC. . . . : 10.IfO-min 10GO- min ABSTRACTION COEFF: 0.20 PEAR RATE: 0 .82 cfs VOL: 0.32 Ac-ft TIME: 480 min 4/17/00 8 :33 :3 am Marley Young Engineer page 5 SHELTON SPRINGS LIGHT INDUSTRIAL RayAllen len 2 . 95 Acres Stormwater Control ----------------------- BASIN SUMMARY BASIN ID: a NAME: Total of Lot No. End 1/2 SE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.94 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 .56 inches AREA. . : 0,79 Acres 1 .15 Acres TIME INTERVAL. . . . : 5. 00 min CN. . . . : 71.80 98 .Q0 TC. . . . : 10.00 min 10 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0.63 cfs VOL: 0.26 Ac-ft TIME: 480 min BASIN ID: b NAME: Total of Lot No. End 2 S Event SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.94 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4 .00 inches AREA. . : 0 . 79 Acres 1.15 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 71. 80 98 . 00 TC. . . . : 10 .00 min 10. 00 min ABSTRACTION COPF'F: 0.20 PEAK RATE: 1.14 cfs VOL: 0.46 Ac-ft TIME: 480 min BASIN ID: c NAME: Total of Lot No. End 10Y Event SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.94 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 5 .50 inches AREA. . : 0. 79 Acres 1.15 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 71.80 98 . 00 TC. . . . : 10 .00 min 10 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 1.70 cfs VOL: 0. 67 AC-ft TIME: 480 min BASIN ID: d NAME: Total of Lot No.End 100Y Event SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.94 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 8 .50 inches AREA. . : 0 .79 Acres 1.15 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 71.80 98.00 TC.-, 10.-00-thin - -10.00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 2 . 89 cfs VOL: 1.13 Ac-ft TIME: 480 min 4/17/00 8 :33:3 am Marley Young Engineer page 6 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control 14 -Q STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. 1T A-A Description: Pond for West Side only Length: 66 .00 ft. Width: 15 .00 ft. Side Slope 1: 3 Side Slope 3: 3 Side Slope 2 : 3 Side Slope 4: 3 Infiltration Rate: 6. 00 min/inch STAGS <----STORAGE----> STAGS <----STORAGE----> STAGE <----STORAGE----> STAGE ----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (£t) ---cf--- --Ac-Ft- 100.00 0.0000 0.0000 101.05 1321 0.0303 102.10 3262 0.0749 103.15 5905 0.1356 100.05 50.109 0.0012 101.10 1399 0.0321 102.15 3371 0.0774 103.20 6050 0.1389 100.10 101.44 0.0023 101.15 1478 0.0339 102.20 3482 0.0799 103.25 6196 0.1422 100.15 154.01 0.0035 101.20 1559 0.0358 102.25 3594 0.0825 103.30 6345 0.1457 100.20 207.82 0.0049 101.25 1641 0.0377 102.30 3708 0.0851 103.35 6495 0.1491 100.25 262.88 n,nn6n lnl.'+O 1724 0.0396 1ng,?5 3824 0.0879 l03.40 6647 0,1S26 100.30 319.19 0.0073 101.35 1809 0.0415 102.40 3942 0.0905 103.45 6801 0.1561 100.35 376.78 0.0086 101.40 1895 0.0435 102.45 4061 0.0932 103.50 6956 0.1597 100.40 435.65 0.0100 101.45 1983 0.0455 102.50 4181 0.0960 103.55 7114 0.1633 100.45 495.80 0.0114 101.50 2072 0.0476 102.55 4304 0.0988 103.60 7273 0.1670 100.50 557.25 0.0128 101.55 2163 0.0497 102.60 4428 0.1016 103.65 7434 0.1707 100.55 620.00 O.Q142 101.60 2255 0.0518 102.65 4553 0.1045 103.70 7598 0.1744 100.60 684.07 0.0157 101.65 2349 0.0539 102.70 4681 0.1075 103.75 7763 0.1782 100.65 749.46 0.0172 101.70 2444 0.0561 102.75 4810 0.1104 103.80 7929 0.1820 100.70 816.19 0.0187 101.75 2541 0.0583 102.80 4941 0.1134 103.85 8098 0.1859 100.75 884.25 0.0203 101.80 2639 0.0606 102.85 5073 0.1165 103.90 8269 0.1898 100.80 953.66 0.0219 101.85 2739 0.0629 102.90 5207 0.1195 103.95 8441 0.1938 100.85 1024 0.0235 101.90 2841 0.0652 102.95 5343 0.2227 104.00 8616 0.1978 100.90 1097 0.0252 101.95 2943 0.0676 103.00 5481 0.1258 100.95 1170 0.0269 102.00 3048 0.0700 103.05 5620 0.1290 101.00 1245 0.0286 102.05 3154 0.0724 103.10 5762 0.1323 4/17/00 8 :33 :3 am Marley Young Engineer page 7 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control ------------ STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct 1T STAGS <-INFILTRATION-> STAGS <-INFILTRATION-> STAGS <-INFILTRATION-> STAGS <-INFILTRATION-> (ft) ---cfa-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 100,00 0.2292 101.05 0.3634 102.10 0.5169 103.15 0.6899 100.05 0.2351 101.10 0.3702 102.15 0.5247 103.20 0.6986 100.10 0.2411 101.15 0.3772 102.20 0.5326 103.25 0.7074 100.15 0.2472 101.20 0.3841 102.25 0.5405 103.30 0.7162 100.20 0.2532 101.25 0.3911 102.30 0.5484 103.35 0.7250 100.25 0.2594 101.30 0.3982 102.35 0.5564 103.40 0.7339 100.30 0.2655 101.35 0.4053 102.40 O.S644 103.45 0.7428 100.35 0.2717 101.40 0.4124 102.45 0.5724 103.50 0.7518 100.40 0.2780 101.45 0.4196 102.50 0.5805 103.55 0.7608 100.45 0.2843 101.50 0.4268 102.55 0.5887 103.60 0.7699 100.50 0.2907 101.55 0.4341 102.60 0.5969 103.65 0.7790 100.55 0.2970 101.60 0.4414 102.65 0.6051 ,103.70 0.7882 100.60 0.3035 101.65 0.4487 102.70 0.6134 103.7S n,7974 100.65 0.3100 101.70 0.4561 102.75 0.6217 103.80 0.8066 100.70 0.3165 101.75 0.4636 102.80 0.6301 103.85 0.8159 100.75 0.3230 101.80 0.4711 102.85 0.6385 103.90 0.8253 100.80 0.3297 101.85 0.4786 102.90 0.6469 103.95 0.8346 100.85 0.3363 101.90 0.4862 102.95 0.6554 104.00 0.8441 100.90 0.3430 101.95 0.4938 103.00 0.6640 100.95 0.3498 102.00 0.5015 103.05 0.6726 101.00 0.3565 102.05 0.5092 103.10 0.6812 4/17/00 8 :33 :3 am Marley Young Engineer page 8 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control B- g STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. 2T -g Description: Pond for East Side only Length: 34. 00 ft. Width: 13 . 00 ft. Side Slope 1: 3 Side Slope 3 : 3 Side Slope 2 : 3 Side Slope 4 : 3 Infiltration Rate: 6. 00 min/inch STAGS <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> STAGS <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- 100.00 0,0000 0.0000 101.30 839.25 0.0193 102.60 2313 0.0531 103.90 - 4580 0.1051 100.05 22.454 0.0005 101.35 883.20 0.0203 102.65 2385 0.0547 103.95 4685 0.1076 100.10 45.622 0.0010 101.40 928.09 0.0213 102.70 2457 0.0564 104.00 4792 0.1100 100.15 69.513 0.0016 101.45 973.94 0.0224 102.75 2531 0.0581 104.05 4900 0.1125 100.20 94.136 0.0022 101.50 1021 0.0234 102.80 2606 0.0598 104.10 5009 0.1150 100.25 119 50 C 55.2.. .....�27 ,...�. 1069 0.0245 ........,.. 2v33 ...voIo ivY.i;i Sit^v v.ii 75 100.30 145.61 0.0033 101.60 i117 0.0256 102.90 2760 0.0634 104.20 5233 0.1201 100.35 172.49 0.0040 101.65 1167 0,0268 102.95 2839 0.0652 104.25 5347 0.1227 100.40 200.13 0.0046 101.70 1218 0.0280 103.00 2919 0.0670 104.30 5462 0.1254 100.45 228.55 0.0052 101.75 1270 0.0291 103.05 3000 0.0689 104.35 5579 0.1281 100.50 257.75 0.0059 101.80 1322 0.0304 103.10 3083 0.0708 104.40 5697 0.1308 100.55 287.75 0.0066 101.85 1376 0.0316 103.15 3166 0.0727 104.45 5817 0.1335 100,60 318.55 0.0073 101.90 1431 0.0329 103.20 3251 0.0746 104.50 5938 0.1363 100.65 350.17 0.0080 101.95 1487 0.0341 103.25 3338 0.0766 104.55 6061 0.1391 100.70 382.61 0.0088 102.00 1544 0.0354 103.30 3425 0.0786 104.60 6185 0.1420 100.75 415.88 0.0095 102.05 1602 0.0368 103.35 3514 0.0807 104.65 6311 0.1449 100.80 449.98 0.0103 102.10 1661 0.0381 103.40 3604 0.0827 104.70 6438 0.1478 100.05 484.94 0.0111 102.15 1721 0.0395 103.45 3696 0.0848 104.75 6567 0.1508 100.90 520.76 0.0120 102.20 1783 0.0409 103.50 3789 0.0870 104.80 6697 0.1537 100.95 557.44 0.0128 102.25 1845 0.0424 103.55 3883 0.0891 104.85 6829 0.1568 101.00 595.00 0.0137 102.30 1908 0.0438 103.60 3978 0.0913 104.90 6963 0.1598 101.05 633.44 0.0145 102.35 1973 0.0453 103.65 4075 0.0936 104.95 7098 0.1630 101.10 672.78 0.0154 102.40 2039 0.0468 103.70 4174 0.0958 105.00 7235 0.1661 2.01.15 713.02 0.01" 102.45 2106 0.0483 103_7S 4273 0.0981 101.20 754.18 0.0173 102.30 2174 0.0499 103.80 4374 0.1004 101.25 796.25 0.0183 102.55 2243 0.0515 103.85 4476 0.1028 4/17/00 8 :33 :3 am Marley Young Engineer page 9 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control ------------------------- STAGE STORAGE TABLE infiltration Rating Curve for Storage Struct 2T STAGS <-INFILTRATION-> STAGES <-INFILTRATION-> STAGE <-INFILTRATION-> STAGS <-INFILTRATION-> (ft) ---cfs-- ------- (ft) ---c£a-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- 100.00 0.1023 101.30 0.2066 102.60 0.3406 103.90 0.5043 100.05 0.1058 101.35 0.2112 102.65 0.3463 103.95 0.5112 100.10 0.1093 101.40 0.2159 102.70 0.3521 104.00 0.5181 100.15 0.1128 101.45 0.2206 102.75 0.3580 104.05 0.5251 100.20 0.1164 101.50 0.2253 102.80 0.3638 104.10 0.5321 100.25 0.1201 101.55 0.2301 102.85 0.3698 104.15 0.5392 100.30 0.1237 101.60 0.2349 102.90 0.3757 104.20 0.5463 100.35 0.1275 101.65 0.2398 102.95 0.3817 104.25 0.5534 100.40 0.1312 101.70 0.2447 103.00 0.3878 104.30 0.5606 100.45 0.1351 101.75 0.2496 103.05 0.3939 104.35 0.5679 10Q.50 0.1389 101.80 0.2546 103.10 0.4000 104.40 0.5751 100.55 0.1428 101.85 0.2597 103.15 0.4062 104.45 0.5825 i00460 0.1458 101.90 11,2648 103-20 0.4725 104.50 0.58e8 100.65 0.1508 101.95 0.2699 203.25 0.4187 104.55 0.5972 100.70 0.1548 102.00 0.2751 103.30 0.4250 104.60 0.6047 100.75 0.1589 102.05 0.2803 103.35 0.4314 104.65 0.6122 100.80 0.1630 102.10 0.2856 103.40 0.4378 104.70 0.6198 100.85- 0.1671 102.15 0.2909 103.45 0.4443 104.75 0.6273 100.90 0.1714 102.20 0.2962 103.50 0.4508 104.80 0.6350 100.95 0.1756 102.25 0.3016 103.55 0.4573 104.85 0.6427 101.00 0.1799 102.30 0.3070 103.60 0.4639 104.90 0.6504 101.05 0.1842 102.3S 0.3125 103.65 0.4705 104.95 0.6582 101.10 0.1886 102.40 0.3181 103.70 0.4772 105.00 0.6660 101.15 0.1931 102.45 0.3236 103.75 0.4839 101.20 0.1975 102.50 0.3292 103.80 0.4906 101.25 0.2021 102.55 0.3349 103.85 0.4974 4/17/00 8 :33 :3 am Marley Young Engineer page 10 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2 .95 Acres Stormwater Control --------------------- HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 4/17/00 8:30:40 am CLEARHI9 MOVE a to 1 0.6339 cfs 0.2591 ac-ft 8.00 hrs MOVE b to 2 1.1375 cfa 0.4551 ac-ft 8.00 brs MOVE c to 3 1.7018 cfa 0.6723 ac-ft 8.00 bra MOVE d to 4 2.8876 cfs 1.1259 ac-ft 8_00 hrs LPOOL 1 "1/2" a a T W 9 Description MatchQ PeakQ Sto Din PkStg OutQ hyd Volume 1/3 0.63 0.63 T .. 0.41 9 415.93 ea. LPOOL 2 "2" b b T W 10 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 1.14 1.14 T W 100.85 0.53 10 1631.97 of LPOOL 3 "10" c c T W 11 Description MatchQ PeakQ Sto Din PkStg OutQ hyd Volume 10 1.70 1.70 T W 101.57 0.67 11 3448.57 of LPOOL 4 "100" d d T W 12 Description MatchQ PeakQ Sto Din PkStg OutQ hyd Volume 100 2.89 2.89 T W 103.01 0.98 12 8419.31 of SPLIT W 1 13 17 0.0000 cfa 0.0000 ac-ft 0.00 bra 0.4124 cfa 0.2591 ac-ft 8.33 brs S=T W 2 14 18 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.5259 cfs 0.4551 ac-ft 8.67 hrs SPLIT W 3 15 19 0.0000 cfa 0.0000 ac-ft 0.00 hrs 0.6686 cfs 0.6723 ac-ft 9.17 hrs SPLIT W 4 16 20 0.0000 cfs 0.0000 ac-ft 0.00 brs 0.9818 cfs 1.1259 ac-ft 9.25 hra MOVE 1a to 1 4/17/00 8:33:3 am Marley Young Engineer page 11 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2.95 Acres Stormwater Control HISTORY OF HYDROGRAPH ACTIVITY 0.3936 cfa 0.1642 ac-ft 8.00 bra MOVE 1b to 2 0.7285 cfe 0.2941 ac-ft 8.00 hre MOVE lc to 3 1.1093 cfe 0.4397 ac-ft 8.00 bra MM 1d to 4 1.9169 cfe 0.7461 ac-ft 8.00 bra LPOOL 1 "1/2" la la 1T W 9 Description MatchQ PeakQ Sto Dis Pk$tg oatQ hyd Volume 1/2 0.39 0.39 1T W 100.24 0.26 9 251.77 of WOOL 2 "2" lb lb 1T W 10 Descriptim MatchQ PeakQ Sto Die PkStg outQ hyd Volume 2 0.73 0.73 1T W 100.86 0.34 10 1044.95 of LPOOL 3 010" lc lc 1T W 11 Description MatcbQ PeakQ Sto Die PkStg OutQ hyd Volume 10 1.11 1.11 1T W 101,60 0.44 11 2246.32 of LPOOL 4 "100" Id Id 1T W 12 Description MatchQ PeakQ Ste Die PkStg OutQ byd Volume 100 1.92 1.92 IT W 203.01 0.67 12 5513.90 of SPLIT W 1 13 17 0.0000 cfe 0.0000 aO-£t 0.00 bre 0.2581 cfe 0.1642 ac-ft 8.33 hrs SPLIT W 2 14 18 0.0000 cfs 0.0000 ac-ft 0.00 bra 0.3382 cfe 0.2941 ac-ft 8.75 brs SPLIT W 3 I5 19 0.0000 cfe 0.0000 AC-ft 0.00 bra 0.4407 cfa 0.4397 ac-ft 9.17 bra - SPLIT W 4 16 20 0.0000 cfe 0.0000 ac-ft o.00 hre 0.6660 cfa 0.7461 ac-ft 9.25 bra ,OD/Jv MOVE 2a to 1 0.2438 cfe 0.0962 ac-ft 8.00 bra MOVE 2b to 2 0.4142 cfs 0.1630 ac-ft 8.00 hrs 4/17/00 8 :33 :3 am Marley Young Engineer page 12 SHELTON SPRINGS LIGHT INDUSTRIAL Ray Allen 2.95 Acres Stormwater Control HISTORY OF HYDROGRAPH ACTIVITY MOVE 2c to 3 0.5992 cfs 0.2352 ac-ft 8.00 hrs MOVE 2d to 4 0.9801 cfs 0.3835 ac-ft 8.00 hrs LPOOL 1 "1/2" 2a 2a 2T W 9 Descripticn MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 1/2 0.24 0.24 2T W 100.48 0.14 9 247.80 cf LPOOL 2 "2" 2b 2b 2T W 10 Description MatchQ PeakQ Sto Die PkStg outQ hyd Volume 2 0.41 0.41 2T W 101.11 0.19 10 677.33 cf LPOOL 3 "10" 2c 2c 2T W 11 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 10 0.60 0.60 2T W 101.77 0.25 11 1292.89 cf LPOOL 4 "100" 2d 2d 2T W 12 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd - Volume 100 0.98 0.98 2T W 102.90 0.38 12 2766.87 cf SPLIT W 1 13 17 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.1376 cfs 0.0962 ac-ft 8.42 hrs SPLIT W 2 14 18 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.1891 cfs 0.1630 ac-£t 8.67 hrs SPLIT W 3 15 19 0.0000 cfs 0.0000 ac-ft 0.00 bra 0.2518 cfe 0.2352 ac-ft 0.92 bra SPLIT M 4 16 20 0.0000 efs 0.9000 ac-ft 0.00 bra - - - - -- - - ---- .3762 c fs 0.3835 ac-ft 9.17 bra End program file C:\EGMOUS\PROJ\RAYALEN2.pgm MARLEY L. YOUNG, CONSULTING ENGINEER P.O. BOX 1343, SHELTON, WA 98584-0959 (360) 426-7475 FAX (360) 426-5789 Civil Engineering Marley L. Young, P.E., P.L.S. Stornmater Site Plena Civil Engineer& Land Surveyor Sewer Extension ED June 23, 2004 RECEIVED Tammy Clark IjUN 2 3 2004 Mason County Planning Dept. 411 N. 5'' Street CEDAR ST-' Shelton, WA 98584 426 W: Re: Michael Allen COM 200400135 Classic Auto RV Storage Dear Tammy: Enclosed is a copy of the Erosion and Sediment Control Site Plan(report)dated April 18,2000 and the civil drawing dated April 05,2001, for the above-referenced project. The original report took into consideration the possibility of impervious surface for building and parking in what is now Lot 1. I have reviewed this report and am convinced that the original stormwater control calculations provided sufficient impervious areas to still be valid under Michael Allen's new proposal. Bioswales and pond size are more than adequate to handle the new proposal. The civil drawings show the existing building in Lot 2 as well as the areas for future building and future parking in Lot 1. These future building sites and future parking were considered as impervious surfacing in the report. Please contact me if you have any questions. Sincerely, Marley L. Young, E. L.S.