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Prelim Drainage Report 12-05-06 001i~ 1 i~ Burnett Road Commercial Park Phase II Preliminary Drainage Report November 2006 ~F^ 0,5 /l ` G ~ - DESIGNBUILD • CIVIL AND lR.4N5PORTATION ENGINEERING • PL4NNING • SURVEYING Preliminary Drainage Report Burnett Road Commercial Park Phase II Yelm, Washington November 2006 Project Information Project: Burnett Road Commercial Park Phase II Prepared for: Burnett Road Commercial Pazk LLC Contact: Steven L. Chamberlain 4200 6~ Ave. SE, Ste. 301 Lacey, WA 95503 (360) 493-6002 Reviewing Agency Jurisdictlon: City of Yelm, Washington Project Number: Project Contact: Project Engineer Prepared by: SCA Consulting Group 4200 6d' Ave. SE, Lacey, WA 98509 (360) 493-6002 FAX (360) 493-2476 Contact Steven L. Chamberlain, P.E. SCA Project: 04073 File Number: g:\text\pf\01001\Reports\ph2_pdr.rtf PROSECT ENGINEERS CERTIFICATION: I hereby certify that this Preliminary Drainage Report for Ne Burnett Road Commercial Park Phase II m Yelm Washington has been prepared by me or under my supervision and meets ffie vnent o(the CtTy of Yelm Development Gu[detinee and Washington State Department of Ecology (WSDOE~ S[ormwater Management Manual for 8~e Puget Sound Basin unless noted o[herwise, and normal standards of engineering prac6cc. I understand that the juriadictlon does mt and x¢11 not assume liability for the su[hdency, suitabiury, or pecfotinnnce oC drainage facilSties designed far this development i~ i~ TABLE OF CONTENTS APPENDICES Appendix I -Pmliminary Dreinagc PARTISTORNI D RAINAGE REPORT ......................................................._............................ ...1 Calculations SECTION 1 - PROPOSED PROJECT DESCRIPTION ........................____ . 1 SECTION 2- EXISTING CONDITIONS ......................................_.._........ ..3 Appendix n-Preliminerv Dminagc SECTION 3 - INFILTRA"fION RATES ........................_............................ ..3 and TeSC Plan ' SECTION 4 - WELLS AND SEP"fIC SYSTEMS.........._ ............................ ..4 SECTION 5 - FUEL TANKS .............................................................._....... ..q Appendix III - FF.MA FIRM Map SECTION 6- SUB-BASIN DESCRIPTION ......................................._....... ..4 gppendix rv-Facility 8ummaey SECTION 7 - ANALYSIS OP 100-YEAR FLOOD...._ ..........................__. ..4 Forms ' SECTION 8 - AESTHETIC CONSIDERATIONS FOR FAC(LiTIES........ ..4 SECTION 9- DOWNSTREAM ANALYSIS AND FACILITY SILiNG.... ..4 Avp~ndix v-vicinity Map SECTION 10 - COVENANTS; DEDICATIONS, EASEMENTS .................. ..5 PART 11- ER0810 N CONTROL REPORP .............................................................................. ._fi SECTION 1 - CONSTRUCTION SEQUENCE AND PROCEDURE......... ..6 SECTION 2 - TRAPPING SEDIMENT ................._.................................... ..6 SECTION 3 - RESTORATION PERMANENT EROSION CONTROL & SITE 7 SECTION 4 - GEOTECF[NICAL ANALYSIS AND REPORT ................... ..7 SECTION 5 - INSPECTION SEQUENCE ................................................... ..7 SECTION 6 - CONTROL OF POLLUTANTS OTHER THAN SED]MENTS. ..7 PART III - bIA1NT ENANCE ALA.R .......................................................................................... ....8 SECTION 1 - REQUIRED MAINTENANCE ......................._.................... 10 SECTION 2 - RESPONSIBLE ORGANIZATION ...................................... 18 SECTION 3 - VEGETATION MANAGEMENT PLAN ............................. IS ' SECTION4- SOURCE CONTROL.._ ........................._............................. 18 1 Parr I Preliminary Storm Drainage Report B ttR dC IPakPh IIPeI' ryD 'nag R p rt i~ PART I STORM DRAINAGE REPORT SECTION 1 - PROPOSED PROJECT DESCRIPTION Project Proponent: Burnett Road Commercial Pazk LLC 4200 6~^ Ave. SE, Ste. 301 Lacey, WA 98503 (360) 493-6002 Parcel Numbers: 21713340600 Total Site Area: 0.98 Acres Zoned: C-1 Site Address: Burnett Road, Yelm, WA 98597 Required Permits: Grading, Utility, Building, Plumbing, Electrical, Mechanical etc. Section, Township, Range: Section 13, Township 17 North, Range 1 East, W.M., Thurston County, WA Site Location: The site is located in Yelm, Washington and is bordered on the west by Burnett Road and situated about 600ft. north from Yelm Ave. Project Overview: The proposal is to develop the 0.98 acres into two office buildings with about 12,540 sf of total floor azea. The development of the proposed site will be constructed in one phase and will include appropriate erosion control measures as needed, grading, storm drainage improvements and extension ofunderground utilities including sanitary sewer. Storm Drainage Improvements: The completed project will create approximately 0.51 acres of new impervious driveways, parking, etc.; 0.21 acres of new roof; and 0.26 acres of disturbed pervious area. SCA Consulting Group Page 1 November 2006 ' B tt R tl C ~ 1 P k Ph II Prelm'nary Dra page Report ' All project impervious areas (roads, walks, roofs) are accounted for below: Posk-Development Basin Area Summary ___- ~ Basin "A1° - Basin "A2" Total _ ___ m erviousRoof lI 0.09 ac ! _. 0.21 ac 0.30 ac mpervious Roadway, arking, Driveways and 0.19 ac 0.51 ac 0.70 ac idewalk _ Disturbed Pervious _0.04 ac Total Developed 0.32 ac Area ~ * _ 0.20 ac __ 0.92 ae 0.24 ac 1.24 ac ~ - *The above numbers include also existing storage building root antl pavetl area in phase I. 1 Storm water Treatment, Storage and Infiltration: 1 Stora a Ca acct Summa _ Basin ID Impervious Area Includin Roo Disturbed Pervious Area Storage [p Re uired _ Storage Provided _ Basin Al 0.28 ac 0.04 ac 350 cf 522 cf Basin A2 _ 0.72 ac 0.20 ac 514 cf 2,218 cf TOTAL 1.0 ac 0.24 ac 864 cf 2,740 cf 1 (1) Hesed on design infiltration rate of 20-inches/hour using Storm Shed modeling software Cor the 100- year storm even[ Storm water treatment design requirements aze based on the 1992 edition of the WSDOE Storm water Management Manual. Treatment calculations are provided in Appendix I. Only a small amount of the landscaping area in the basins is tributary to the treatment facilities, and is unlikely to generate appreciable runoff due to the very well- drained soil. Therefore, disturbed pervious areas might be deemed insignificant and ' might be excluded From the treatment calculations. Basin Al: Basin `A l' includes 1 mini storage building with 0.09 ae of existing impervious roof, 0.19 ac of existing paved area and 0.04 ac of existing landscaping located in Phase i north of Phase II. Runoff ' from this area will be directed toward existing catch basins. After storage in existing underground gallery the runoff will be treated by 24" deep sand filter before infiltration to groundwater. The DOE manual required 6-month event [o be treated. Treatment of runoff for storm events up to the 100-year event by passage of runoff tbrough (effectively) a 2-foot deep sand filter. For treatment requirements of infiltration systems the 1992 DOE manual provides following design criteria: ' Figure I--3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to ] 2 inches deep. Thus the depth of The sand filter proposed in This project exceeds the design cntena. Runoff will infiltrate through native material below the upper layer soil. DOE Manual requires that runoff From the 6-montlr 24-hour storm be treated. This proposal will treat runoff from all events up to and exceeding the 700-year, 24-hour event, thus exceeding DOE Manual requirements. ' SCA Consulting Group Page 2 November 2006 1 t 1 1 1 1 i B I1 R d C ~ I P k Ph II P I'm nary 0ranaoe Report Basin A2: Basin `A2' includes 2 proposed building with 0.21 ac of new impervious roof, 0.5I ac of new paved area and 0.04 ae of associated landscaping. Runoff from this area will be intercepted by catch basins and conveyed into an existing underground gallery for storage. After storage the runoff will be treated by 24" deep sand filter before infiltration to groundwater. The DOE manual required 6-month event to be trcaied. Treatment of runoff Tor storm events up [o the 100-year event by passage of runoff through (effectively) a 2-foot deep sand filter Por treatment requirements of infiltration systems the ]992 DOE manual provides following design criteria: Figure III-3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to 12 inches deep. Thus the depth of [he sand filter proposed in this project exceeds the design criteria. Runoff will infiltrate through native material below the upper layer soil DOE Mannal requires that mnoff from the 6-month 24-hour storm be treated. This proposal will treat runoff from all events up to and exceeding the 100-year, 24-hour event, thus exceeding DOE Manual requirements. Roof Runoff: All roof runoff from the proposed office buildings will be collected by roof drains, flow through underwalk drains, will be intercepted by catch basins located in pazking lot and forwarded to existing infiltration gallery Cor storage. 24° deep sand filter will provide treatment before infiltration to groundwater. SECTION 2 -EXISTING CONDITIONS The site is 0.95 acre triangular in shape with 200 feet fronting Burnett Road. The site is fairly flat with gentle slopes to the northwest with low elevations of approximately 337 ft. located notherly on the western property line. The highest elevation of 339 ft is at the south oC the property. The site is currently vacant land. The site is covered with a light density of Scotch Broom growth with indigenous field grasses. The project site is bounded by similarly zoned properties to the north, east and south, Burnett Road to the west. On site soils are well drained and formed in glacial outwash. There aze no creeks, lakes, ponds, springs, wetlands, ravines, gullies, steep slopes or other environmentally sensitive areas identified onsite or down gradient of the subject property. The site is located in an aquifer sensitive area, according to the 1986 Thurston County Comprehensive Plan M-S. The site is not located in a wellhead protection area. SECTION 3 -INFILTRATION RATES The Soil Conservation Service (SCS) Soil Survey of Thurston County classifies onsite soils as Spanaway (110) series. The design infiltration rate of 20 in/hr was assumed for the purposes of this study. IL is reasonable infiltration rate for this soil group in Yelm Area. SCA Consulting Group Page 3 November 2006 1 1 1 1 1 B tt R d C I Pa k Ph II Prel' - ry D 'nag R p rt SECTION 4 -WELLS AND SEPTIC SYSTEMS No onsite wells were found during our site investigation of the proposed site. Existing home is served by City water. No onsite well logs were Cound at the Department of Ecology. No abandoned or existing septic systems were identified during SCA's site investigation or at the Thurston County Development Services office. Any septic system found will be removed in accordance with Thurston County Depaztment of Health standards. SECTIONS- FUEL TANKS No fuel tanks were located during SCA's site inspection or during soils work. Additionally, a review of the DOE's Leaking Underground Storage Tank (LUST) list did ' not indicate any existing or abandoned fuel tanks on the project site. SECTION 6 - SUB-BASIN DESCRIPTION ' The project site is located in the Thompson Creek Drainage Sub-Basin, Nisqually River Drainage Basin per Thurston County Comprehensive Map M-4. ' During SCA's site investigation and soils analysis, it appeazed that all onsite stormwater runoff is contained onsite and infiltrated back into the groundwater, which is typical of the site's soil classification. All onsite stormwater runoff will be contained and infiltrated onsite. There does not appear to be any significant existing offsite drainage to Che property. ' No hazardous materials handling is anticipated in the area tributary to the storm drainage facilities. ' SECTION 7 - ANALYSIS OF 100-YEAR FLOOD This project does not lie adjacent to or contain a stream onsite and has not been identified as a 100-year flood hazazd area. A FEMA FIRM Map is included in Appendix III. ' SECTION 6 - AESTHETIC CONSIDERATIONS FOR FACILITIES The storm drainage facilities are located underground. All previous disturbded areas ' will be vegetated and landscaped. SECTION 9 - DOWNSTREAM ANALYSIS AND FACILITY SIZING ' Sizing calculations for the project's stormwater treatment, storage, and infiltration facilities are provided in Appendix I of this report. All calculations correspond to the Preliminary Grading, Drainage Plan, which can be found in Appendix II of this report. Since all stormwater will be infiltrated onsite, a downstream analysis was deemed unnecessary. ' SCA Consulting Group Page 4 November 2006 B ttR dC IP kPha IIP I' ryD Rep n i~ SECTION 10 - COVENANTS, DEDICATIONS, EASEMENTS OnsiCe drainage facilities including pipes, wet vaults, and infiltration galleries will require routine maintenance. The maintenance manual prepared for the project will list the mainCenance requirements. A copy of the completed Maintenance Manual can be supplied to the Ciry upon completion of the project. SCA ConsWling Group Navemher 200fi 5 I I , Part II Erosion Control Report I , 1 1 1 1 1 B fl R atl C ~ I Pa k Ph II Pr I' 'nary Dra nape Report PART II -EROSION CONTROL REPORT SECTION 1 - CONSTRUCTION SEQUENCE AND PROCEDURE The proposed commercial development will include site grading and erosion control measures designed to contain silt and soil within the project boundazies during construction until permanent vegetation and site improvements are in place. Erosion/sedimentation control shall be achieved by a combination of structural/vegetative cover measures and construction practices tailored to fit the site. Best Management Practices (BMP's) will be employed to properly cleaz and grade the site and to schedule construction activities. Before any construction begins onsite, erosion control facilities shall first be installed. The planned construction sequence is as follows: 1. Schedule preconstruction conference with the city, contractor, project engineer, and construction-staking surveyor. 2. Install rock construction entrance. Use 4° to 8" diameter spalls with 12" minimum depth. 3. Install filter fabric fencing in the locations shown on the plans. 4. Cleaz site (grubbing and rough grading). 5. Maintain equipment and water supply for dust control. 6. Designate an azea for washing concrete trucks to control the runoff and eliminate entry into the storm drainage system. 7. Install underground utilities (water, sewer, storm). 8. Provide inlet protection azound all new catch basins. 9. Construct roadway and parking and install landscaping, sod and/or seed, and mulch all disturbed azeas. 10. Maintain all erosion control facilities until the entire site is stabilized and silt runoff ceases. ' SECTION 2 - TRAPPING SEDIMENT Filter Fabric fencing will be installed to trap sediment before runoff exits the site. In addition, inlet protection will be installed azound all existing and new catch basins to filter out sediment before runoff enters the storm system. A stabilized construction entrance will be installed to prevent construction vehicles from tracking soil onto roadways. If sediment is tracked offsite, it shall be swept or shoveled Crom paved surfaces on a daily basis, so that it is not washed into existing catch basins or other storm drainage facilities. t During the rainy season Crom November 1 through Mazch 31, the contractor must cover any disturbed areas greater that S,000sf in size if they will be unworked for more than ' 12 hours. Mulch, sodding, or plastic covering shall be used to prevent erosion in these azeas. 1 SCA Consulting Group Page 6 November 2006 1 1 B tt R ad C I Pa k Ph II P fm nary Dra nape Report SECTION 3 - PERMANENT EROSION CONTROL 8 SITE RESTORATION All disturbed areas will be paved with asphalt, covered by buildings, or landscaped with grass, shrubbery, or trees per the landscaping plans. SECTION 4 - GEOTECHNICAL ANALYSIS AND REPORT ' None of the storm drainage facilities are located near the top of a steep slope. Therefore, a geotechnical analysis for slope or soil stability was deemed unnecessary. SECTION 5 - INSPECTION SEQUENCE In addition to required City inspections, the Project Engineer will inspect facilities related to stormwater treatment, erosion control, storage, and conveyance during ' construction. A[ a minimum, [he following items shall be inspected at the time specified: ' 1. The erosion control facilities shall be inspected before the start of clearing and grading to ensure the following structures are in place: a. Construction Entrance b. Filter Fabric Fences ' c. Inlet protection of new catch basins 2. The conveyance systems will be inspected after construction of the facilities, but ' before project completion to ensure the following items are in working order: a. Pavement Drainage t b. Catch Basins c. Conveyance Piping d. Roof Drain Piping ' 3. The infiltration galleries shall be inspected during construction to ensure that the facility is constructed to design specifications. ' 4. The permanent site restoration measures shall be inspected after landscaping is completed. ' A final inspection shall be performed to verify final grades, settings of structures and all necessary information to complete the Engineer's Construction Inspection Report Form. This form must be completed prior to final public works construction approval. SECTION 6 - CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS The contractor will be required to designate a washdown area for concrete trucks as well as a temporary stockpile area for construction debris. Catch basin inlet protection and filter fabric fencing shell remain in place until construction on the site is complete. 1 ' SCA Consulting Group Page 7 November 2006 1 PaYt lu Maintenance Plan B tt R d C I P k Ph II Prel'm'nary Dra nage Report I' PART III -MAINTENANCE PLAN INSTRUCTIONS FOR MAINTENANCE OF STORM DRAINAGE FACILITIES The following pages contain maintenance needs for most components that aze part of the drainage system. A checklist should be completed for all system components according to the following schedule: 1. Monthly from November through April 2. Once in late summer (preferably September) 3. After any major storm (use 1" in 24-hours as a guideline) items marked "S" only. Using photocopies of these pages, check oft the problems identified with each inspection. Add comments on problems Cound and actions taken. Keep these "checked" sheets in a file, as they will be used to write the annual report (due in May of each year). Some items do not need to be checked with every inspection. Use the suggested frequency at the left of each item as a guideline for the inspections. The City of Yelm is available for technical assistance. Do not hesitate to call, especially if it appears that a problem may exist. SCA Consulting Group Page 8 November 2006 Burnett Road Commercial Park Phase II Prelim nary Drainage Report i~ ATTACHMENT "A": MAINTENANCE PROGRAM COVER SHEET Inspection Period: Number of Sheets Attached: Date Inspected: Name of Inspector: Inspector's Signature: SCA Consulting Group November 2006 Page 9 B t1R dC me IP kPhas IIP I' ryD ~ R p rt I ' SECTION 1 - REQUIRED MAINTENANCE The drainage facilities will require occasional maintenance. The checklists below are the minimum maintenance requirements and inspection frequencies. Maintenance Checklist for Conveyance Systems (Pipes and Swales) Frequency Drainage ~ Problem Conditions to Check For Conditions That Should System Req'd Exist Peatu[e M.S. Pipes d Sediment& Accumulated sediment that Pipe eleened of all debris exceeds 20 % of the diameter of sediment and debris. [he pipe. M ~ Vegetation Vegetation that reduces free All vegetation removed so movement of water through pipes. water flows freely. A ~ Damaged Protective coating is damaged, Pipe repaired or replaced. (msted, rust is causing more than 50% bent o[ deterioration to evy part of pipe. crushed) M v Any dent [ha[ significantly Pipe repaired or replaced. impedes flow (i.e., decreases the cross section area of pipe by more they 20%). M ~I Pipe has major cracks or tears Pipe repaired or replaced. allowing groundwater leakage. M.S. Swales Trash & Dumping of yard wastes such as Remove trash and debris debris grass clippings and branches into and dispose as prescribed Swale. Awumula[ion of mn- by City Waste degradable materials such as Management Section. glass, plastiq metal, foam and coated paper. M Sediment Accumulated sediment that Swale cleaned of all buildup exceeds 20 % ofthe design depth. sediment and debris so that it matches design. M Vegetation Grass cover is sparse and weedy Acrale soils and reseed not or areas ure overgrown with and mulch bare areas. growing or woody vegetation Maintain grass height at e overgrown minimum of 6" Cor best SlOrmwate[ hefltment. Remove woody growth, recontour and reseed az necessary. M Conversion Swale has been filled in or If possible, speak with by owne[ Io blocked by shed, woodpile, owner and request that incompatibl shrubbery, etc. Swale area be restored. e use Contact City to report problem if not rectified voluntarily. A Swale does Water stands iu Swale or flow A survey may be needed not draw velocity is very slow. Smgnation to check grades. Grades occurs, need lobe in 7 % range if ossible. If rode is less SCA Consulting Group November 2x06 Page 10 ' B tt Roatl C I Pa k Ph II P I' ary D R p rt Frequency Drainage 1f Problem Conditions to Check Por Conditions Tha[ Should System Rcq'd Exist Feature than 1%, underdrains may need to be installed. I[you nre uvsure whraheroproblem exists, please conwd thclurisdiumn and esk (or mchnicnl aasiswnce. Commenu' Key A=Annual (March or April preferred) M = Mnnlhly (sac schedae) s-anor major srorms 1 1 1 1 ' SCA Consulting Group Page it November 2006 Burnett Road Commercial Park Phase II Preliminary Draina Report ATTACHMENT "A" (CONTINUED) Maimenattee Checklist for Catch Basins and lnlets Frequency Drainage ~ problem Conditions to Check Far Conditions That System Should Exist Feature M.S. General ~ 'fresh, debris end Trash or debris in front of No trash or debris sediment in or on the catch basin opening is located basin blocking capacity by more immediately in than 10%. front of catch basin opening. Grate is kept clean and allows water to cuter. M ~ Sediment or debris (in the No sediment or basin) that exceeds 7/3 the debris in the catch depth from the bottom of basin. Catch basin basin to invert of the is dug out and lowest pipe into or out of clean. the basin. M.S. ~ Trash ar debris in any inlet Inlet and outlet or pipe blocking more than pipes free oRrash 7/3 of its height. or debris. M ~ Stmcmral Come[ of name extends Frame is even with damage to Frame more than 3/4" past curb curb. and/or top slab face inm the street (if applicable). M ~ Top slab has holes larger Top slab is free of than 2 square inches ar holes and cracks. cracks wider than 1/4" (intent is to make sure all material is running into the basin). M vl Frame not sitting flush on Frame is sitting top slab, i.e., separation of Eush on mp slab. more than 3/4" oP the frame from the top slab. A ~ Cracks iv basin Cracks wider than IR" and Basin replaced o[ walls/bottom longer than 3', any repaired ro design evidence of soil particles standards. Contact entering catch basin aprofessional through cracks or engineer for maintenance person judges evaluation. that structure is unsound. A y' Cracks wider than 1/2" and No cracks more longer than I'at the joint than 1/4" wide a[ of any inletloutlet pipe or thejoint of any evidence of soil inlet/outlet pipe. particles enle[ing catch basin through crack3. SCA Consulting November 2006 Page 12 I ' B tt R d C me - I P k Ph se II P f ary Dra nape Report 1 1 1 Frequency Drainage System ~ Problem Conditions to Chcok For Conditions That Should Exist Feature A ~ SelllemenNmis- Basin has settled mare then Basin replaced or alignment 1" or has rovaved more than repaired to design 2"out of alienment. standards. Contact a professional engineer far evaluation. M.S. ~ Fire hazard or Presence of chemicals such No color, odor or other pollution as natural gas, oil and sludge. Basin is gasoline. Obnoxious dug out and clean. color, odor or sludge oared. M.S. ~ Outlet pipe is Vegetation or roots No vegetation or clogged with growing in inleUautlet pipe root growth vegetation joints that is more than 6" present. tall and less than 6" apart. Ifyou ore ansurz whether a problem extsq please coulee', the Jurisdiction and ask for technical essismnce. Com en6 Keym A=Annusl (March o~April prefrteAJ M=Monthly (see scheJUlc) S =after major norms SCA Consulting Group November 2006 Page t3 ' B tt Road C I Pa k Ph II Prefmnary Dra nage Repod t ATTACHMENT "A" (CONTINUED) Maintenance Checklist for In£ltration Systems Frequent Druinage J Problem Conditions to Check Conditions That Should y System For Exist Feature M,S General Trush & See Maintenance See Maintenance debris Checklist for Ponds. Checklist for Ponds. buildup in pond M Poisonous See Maintenance See Maintenance vegetation Checklist for Ponds. Checklist For Ponds. M,S Fire hazard See Maintenance See Maintenance or Checklist (or Ponds. Checklist for Ponds. pollution M Vegetation See Maintenance See Maintenance not Checklist for Ponds. Checklist Cor Ponds. growing or is overgrown M Rodent See Maintenance See Maintenance holes Checklist for Ponds. Checklist for Ponds. M Insects See Maintenance See Maintenance Checklist for Ponds. Checklist for Ponds. A Storage J Sediment A soil texture test Sediment is removed area buildup in indicates facility is not end/or facility is system working at its designed cleaned so chat capabilities or was infiltration system incorrecfly designed. works according to design. A sediment [rapping area is installed to reduce sediment transport into infiltration area. A J Storage A soil texture test Additional volume is area indicates facility is not added through drains workng at its designed excavation to provide slowly capabilities or was needed storage. Soil is (more than incorrectly designed. aerated and rototilled 48 hours) to improve drainage. or Contact the Ciry for overflows information on its ~. requirements regarding excavation. SCA Consulting Group Page 14 November 2006 1 i~ 1 B 1t R d C I P k Ph II P f ry Drains R p d M Sediment Aay sedimenT and Clean out sump to trapping debris tilling area to design depth. area 10 % of depth from sump bottom-io-bottom of outlet pipe or obstrucvng flow into the connector pipe. One Time Sediment Stormwater enters Add a trapping area by trapping infiltration area directly constructing a sump azea noT without treatment. for settling o[ solids. present Segregate settling area Crom rest of facility. Contact City far guidance. M Rock J Sediment Hy visual inspection Replace gravel in rock filters and debris little or no water flows filter. through filter during heavy rainstorms. S Infiltratio Infiltration Standing Water in E7ceavate bottom o[ n Failure Inspection W etl Afrer trench as necessary Trenches 48 hours after storm or but at least 3 feet. Overflow during Storms Replace with crushed rock. Check pretreatment systems far effectiveness. Check tributary azea for sediment sources. I[you ere unsure whether a problem exists, please contact the Jurisdiction end ask [or teehviral assistance. Comments: Kev A = Mnual IMarch or April preferred) M =Monthly (see schedule) 5 =After major storms ' SCA Consulting Group Page 15 November 2006 B r ffR dC e IP kPhas IIP f ryD qeR p rt i~ ATTACHMENT "A" (CONTINUED) Maintenance Checklist for (3xounds (Landscaping) Frequen Drainage J Problem Conditions to Check Conditions That Should cv Svsiem For Exist Feature M General J Weeds Weeds growing in Weeds present in less (nonpoisono more than 20 % of the than 5% of the us( landscaped area landscaped area. (trees and shrubs only). M J Safety Any presence of No poisonous vegetation hazard poison iry or other or insect nests present poisonous vegetation in landscaped area. or insect nests. M,5 J Trash or See Ponds Checklist. See Ponds Checklist. litter M,S J Erasion of Noticeable rills aze Causes of erosion are Ground seen in landscaped identified and steps Surface areas. taken to slow down/spread out the water. Eroded areas ere filled, contoured, and seeded. A Trees and J Damage Limbs or parts of Trim trees/shrubs to shrubs trees or shrubs that restore shape. Replace are split or broken trees/shrubs with which affect more severe damage. than 25 % of the total foliage o[ the tree or shrub. M J Trees or shrubs that Replant tree, inspecting have been blown for injury to stem or down or knocked roots. Replace if over. severely damaged. A J Trees or shrubs, Place stakes and which are me rubber-coated ties adequately supported around young or are leaning aver, trees/shrubs for cav sing exposure of support. the roots. I(yoo are uvsure whether e problem er~sts, please onv[aet [he Juristlletion and ask for technical assistance Comments: Kev A =Annual (Memh or April pa(erretl SCA Consulting Novemher 2006 Page 16 B tt R d C ~al P k Ph II P I ry Draina R p h M = Morrthiy see schetlulc~ 9 = ARer major amvms i~ November Group Page 17 B tt Roatl C 'al P k Ph II P f ry D g R p rt SECTION 2 - RESPONSIBLE ORGANIZATION The project owner shall be responsible for the operations and maintenance of all onsite storm drainage facilities. SECTION 3 - VEGETATION MANAGEMENT PLAN All disturbed pervious areas on the site will be landscaped to provide an aesthetically pleasing environment. SECTION 4 - SOURCE CONTROL Warning signs (e.g., "Dump No Waste -Drains to Groundwater') will be embossed or painted on or adjacent to all storm drain inlets and will be repainted periodically as necessary. SCA Consulting Group Page 18 November 2006 I ' 1 Appendix 1 Preliminary Drainage Calculations DRAINAGE CALCULATIONS The following calculations are based on the requirements contained in the 1992 Washington State Depaztment of Ecology (WSDOE) Stormwater Management Manual for the Puget Sound Basin. DESIGN AND BASIN INFORMATION SUMMARY: Soil Classification (Soil Survey of Thurston County, WA): SCS Soil Classification: Spanaway, Nisqually Hydrologic Group: B Design Infiltration Rate: 20 inches/hour SCS Runoff Curve Number: (Table III-1.3 WSDOE Storm Manual) Post-developed (Lawns, 75°/ + grass coven: CN = 80 Post-development (impervious) CN = 98 Pre-development CN = 78 Rainfall Design Storms: (WSDOE Isopluvial Maps -App. AIII-1.1 of WSDOE Storm Manual) 6 month storm (64% of 2 yr. storm) = 1.28" 2 yr./24 hour storm = 2.0" 10 yr./24 hour storm = 3.0" 100 yr./24 hour storm = 4.0" Post-Development Basin Area Summary Basin "Al° Basin "A2" To[al m ervious Roof _ 0.09 ac 0.21 ac 030 ac mpervious Roadway, Parking, Driveways and 0.19 ac 0.5] ac 0.70 ac Sidewalk isturbed Pervious 0.04 ac 0.20 ae 0.24 ac Total Developed 032 ac* 0.92 ac 1:14 ac Arca 'The above numbers include also exis4cg storage buLLamg root end paved area iv phase I. I ' 1 Storm water Treatment: ' Basin `Al': Per Stormshed calculations 6 month event will result in peak flow rate of O.OS cfs. ' RunoFF will be directed towazd catch basins. After storage in underground gallery the runoff will be treated by 24" deep sand Flter before infiltration to groundwater. The DOE manual required 6-month event to be treated. Treatment of runoff (or storm events up to the 100-yeaz event by passage of runoff ' through (effectively) a 2-foot deep sand filter. For treatment requirements of infiltration systems the 1992 DOE manual provides following design criteria: Figure III-3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to 12 inches deep. Thus the depth of the sand filter proposed in this project exceeds the design criteria. Runoff will infiltrate through native material below the upper layer soil. DOE Manual requires that runoff from the 6-month, 24-hour storm be treated. This proposal will treat runoff from all events up to and exceeding the 100-year, 24-hour event, thus exceeding DOE Manual requirements. Basin `A2': 1 Per Stormshed calculations 6 month event will result in peak flow rate of 0.20 cts. Runoff will be directed toward catch basins. After storage in underground gallery the ' runoff will be treated by 24" deep sand filter before infiltration to groundwater. The DOE manual required 6-month event to be treated. Treatment of runoff for storm events up to the 100-yeaz event by passage of runoff ' through (effectively) a 2-foot deep sand Filter. For treatment requirements of infiltration systems the 1992 DOE manual provides following design criteria: Figure I1I3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to 12 inches deep. Thus the depth of the sand filter proposed in this project exceeds the design criteria. ' Runoff will infiltrate through native material below the upper layer soil. DOE Manual requires that runoff from the 6-month, 24-hour storm be treated. This proposal will treat runoff from all events up to and exceeding the 100-year, 24-hour event, thus exceeding DOE Manual requirements: 1 1 1 1 Stormwater Storage and Infiltration: Stora a Ca acit Sum_ ma Basin ID Impervious Area Disturbed Storage (1) Storage Including Roo Pervious Area Recuired Provided Basin Al 0.28 ac 0.04 ac 350 cf 522 cf Basin A2 0.72 ac 0.20 ac 514 cf 2,218 cf TOTAL _ 1.0 ac I 0.24 ac 864 cf 2,740 cf 11) Bascd on design infiltration rate of 20-inches/hour using StormShed modeling software for the 100- ' year storm event Basins Al and A2: See following StormShed softwaze modeling output and spreadsheets for Stormwater storage and infiltration results for basins Al and A2. 1 1 Appended on: 11:42:22 Tuesday, November 28, 2006 LPOOLCOMPUTE [al] SUMMARY using Puls oos- 0 i~me ~~ neu~,p Running C:\\Documents and Settings\\EdM\\My Documents\\al Report.pgm on Tuesday, November 28, 2006 Start of live storage: 328.5200 fr Event Match Q (cfs) Peak Q (cfs) Peak Stg (ft) Vol (cf) Vol (acft) Time to Empty 100 year 0.0012 ~ 0.1111 329.9390 349.86 0.0080 24.50 100 yeas HyJro0~aph Plm (/~~~ ~ ~e1 pev 100 y,eer 0.., I I -. ._ ..- _ U2 iV 100 YPaY JUtf ' ~ 0157 -' 1 -; -: ._..- ___.,..,-.,- ~' ~ ~ .- ', '. Summary Report of all Detention Pond Data ' Event Precip (ia)' 6 month 1.2800 2 year 2 0000 10 year 3 0000 00 year 4.0000 BASLIST2 [aldev] Using [TYPEl A] As [100 year] LSTEND Peak Q Peak T Peak Vol BasinID Event I (cfs) (hrs) ~, (ac-cf) aldev 100 '' 0.2761 8.00 0.0946 year BASLIST ]TYPEIA] AS [100 year] DETAILED Area Method/Loss Raintype. (ac) i 032 ', SCS/SCS ~TYPEIA I , t 1 1 1 1 1 I [a]dev] LSTEND Record Id: al dev Design Method SCS Rainfall type TYPElA Hyd Inri 10.00 min PeakingFactor _... 484.00 '.. __ Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.04 ac DCIA 0.28 ac Pervious CN 80.00 DC CN 98.00 .Pervious TC 9.39 min DC TC 2 02 min Pervious CN Calc Description SubArea Sub cn Open spaces, lawns,parks (>75% grass) 0.04 ac 80.00 Pervious Composited CN (AMC 2) SD.00 I Pervious TC Calc Type Description Length Slope Coeff Mis c TT '..Sheet Short prairie grass and lawns.: 0.15 50.00 ft '.1.00% 0.1500 2 00 m 9.39 min Pervious TC 9 39 min Directly Connected CN Calc Description SubArea ~ Sub cn 0.28 ac Impervious surfaces (pavements, roofs, etc) 98.00 DC Composited CN (AMC 2) 98 00 Directly Connected TC Cale Type Description Length Slope Coeff Misc TT Sheet ,Smooth Surfaces.: 0.011 100.00 ft 1.00% -0.0110 2.00 in 12.02 min Directly Connected TC 2.02min HYDLIST SUMMARY [dummy much] [aldev - 100 year] [100 year out] LSTEND AydID Peak Q (cfs) Peak T (hrs) Peak Vol (ac-ft) Cont Area (ac), dummy much 0.0012 8.00 0.0003 0.0000 aldev - 100 year 0.2761 8.00 0.0946 0.3200 100 year out 0.1111 7 67 STORLIST [trapal] LSTEND 0.0946 0.3200 Record Id: trapal Descrip cb Increment 0.10 ft Start El 328.5200 ft Max El. 333.0200 ft Length '~.40.0O00fr Width 6.O00Oft ,Length ssl O.lOhav Length ss201000hav Width ssl -0.1 Ohav .Width ss2 '.0.1000hav' Only consi _..... _. der bottom area for infiltration DISCHLIST [infiltrational ] LSTEND Record Id: infiltrafional Descnp gallery :Increment 0.10 fr Start EI 328.5200 ft IMax EI. 341 0000 ft Infiltration rate 20.0O00in/hr WP Multiplier .1.00 I ' LPOOLCOMPUTG [a2] SUMMARY using Pnls Start of Irve storage 328 5200 fr ' Eveut Match Q (cfs) Peak Q (cfs) Peak Stg (tt) Val (cf) Vol (acft) Time to Empty 100 year, 0.0012 0.4722 329.0197 5]4.13.0.0118 24.50 100 yeal HyJiogiaph Plot ' ~.~ a;kfev iD0 Yeae ~ 0 i Of - •IY'~700 yC9Y VUf i- °05 _. __.: _.... . .. .~ ~~~ . _ _ I" _ 00.3 . . l . ~--. __., f ~-"~ ~ ~ ~ e2 -. ._ 01 0 n rv m e m m r ~_ m ~ ` ~~ ~~ ~ °1 n n n r n~ Tlmeln Haurs ' Running C:UDocuments and Settings\\EdM\\My Documents\\a2 Report.pgm on Tuesday, November 28, 2006 ' Summary Report of all Detention Pond Data ' Event Precip (in) h 1 2800 6 mont 2 year 2.0000 3.0000 10 year . '100 year:4.0000 BASL15T2 [a2dev] Using [TYPEIA] As [100 year] LSTEND PeakQ PeakT Peak Vol BasinIll Event (cts) (hrs) (ac-cf) a2dev 100 0.7559 8.00 0.2599 year Area Method/Loss Raintype (ac) ', 092 SCS/SCS TYPElA BASLIST ~TYPElA] AS [100 year] DETAILED [a2dev] LSTEND i~ i~ 1 1 1 1 1 Record Id: a2dev Design Method SCS :Rainfall type TYPEI A Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.20 ac DCIA 0 72 ac Pervious CN 80.00 :DC CN 98.00 Pervious TC 9.39 min DC TC 2.67 mm I PerviousCN Calc Description SubArea Sub cn Open spaces; lawns,parks (>75%grass) 0.20 ac 80.00 Pervious Composited CN (AMC 2) 80.00 Pervious TC Calc Type Description Length Slope Coeff ', Mis c TT Sheet Short prairie grass and lawns.: 0.15 50.00 ft 1.00% 0.1500 2.00 m 9.39 min Pervious TC 9.39 min '. Directly Connected CN Calc Description SubArea Sub cn ~, Impervious surfaces (pavements, roofs, etc) 0.72 ac 98.00 DC Composited CN (AMC 2) 98.00 Directly Connected TC Calc Type Description Length Slope Coeff Misc TT Sheet Smooth Surfaces.: 0.011 100.00 ft 0.50°/~ 0 0110 .2.00 in 2.67min ' Directly Connected TC 2 67min HYDLIST SUMMARY [dummy much] [a2dev - 100 year] [100 year out] HydID Peak Q (cfs) Peak T (hrs) :Peak Vol (ac-ft) Cont Area (ac) dummy much 0 0012 : 8.00 0.0003 0.0000 ' a2dev - 100 year 0 7559 8.00 0.2599 0.9200 100 year out 0.4722 '' 7.67 0.2599 0.9200 STORLIST [trapa2] LSTEND Record Id: trapa2 Deserip: cb Increment 0.10 ft Start El 328.5200 ft Max EI. 333.0200 ft. Length 170.0000 fr Width 6.0000 ft 'Length ssl -0.1 Ohav Length ss2 O.1000hav Width ssl O.lOhav Width ss2 0 1000hav Only consider bottom azea for infiltration DISCHLIST [infiltrational ] LSTEND Record Id: infiltrational Descrip gallery .Increment ~ 0.10 ft Star4 El. 328 5200 ft MaxEl. .341.0000 ft Infiltration rate '20.0000 tn/hr'WP Multiplier;1.00 Licensed to: KPFF, Inc. -Olympia BCA Consulting Group Sformwater Storage 11/28/2006 INFILTRATION GALLERY A7: Description: Burnett Roatl Phase 2 Date'. ######ii# Job #: 040]3 For tlesign purposes a 20 in/hr infltration rate was usetl to determine minimum storage requirements 1) Minimum Sformwater Storage Volume Requiretl According to Storm Shetl: Vmin= 350 cf 2) Stomnwater Storage Volume Provitletl: The requiretl volume of 350 cf will be stored and infllratetl usin i under rountl in5ltration drainrock allery(ies) 40 ft. long x 6 ft. wide x 4.5 ft. tleep with ~ft. tliameter pertoratetl pipes. Total gallery storage capacity using 3:1 void ratio: V=N[(L"(W'H-Apipe))'0.3+(gpipe'L)]= 522 cf Storage Volume= 522 cf> Requiretl Volume = 350 cf Therefore is Atlequate. 3) 48-Hour Dmwdown: Volumeinfiltratetl= 19,200 cf/48hrs> 350 cf Therefore is Atlequate. SCA Consulting Group Stormwater Storage 11I28I2006 INFILTRATION GALLERY A2 Description'. Burnett ROatl Phaee2 Date'. ######## Jab#: 040]3 For design purposes a 20 inlhr infltration rate was used to determine minimum storage requirements 1) Minimum Stormwater Storage Volume Required According to StonnShed: Vmin = 514 cf 2) Stormwater Storage Volume Providetl: The requiretl volume of 574 cf will be stored and inFllVatetl usin 1 under round infltration tlrainrock 9_a_Ilery(ies) 170 ft. long x 6 k. wide x 4.5 ft. tleep with 3 k. diameter perforated pipes. Total gallery storage capacity using 3'.1 void ratio: V = N[(L'(W`H-Apipe))'0.3+(Apipe'L)] = 2,218 cf Storage Volume = 2,218 cf> Required Volume = 514 cf Therefore is Adequate. 3) 48-Hour Drawdown: Volume infitratetl= 81,800 cf/48hrs> 514 cf Therefore is Adequate. DRAINAGE CALCULATIONS The following calculations aze based on the requirements contained in the 1992 Washington State Depaztment of Ecology (WSDOE) Stormwater Management Manual Cor the Puget Sound Basin. DESIGN AND BASIN INFORMATION SUMMARY: Soi] Classification (Soil Survey of Thurston County, WA): SCS Soil Classification: Spanaway, Nisqually Hydrologic Group: B Design Infiltration Rate: 20 inches/hour SCS Runoff Curve Number: (Table III-1.3 WSDOE Storm Manual) Post-developed (Lawns, 75%+ grass cover): CN = 80 Post-development (impervious) CN = 98 Pre-development CN = 78 Rainfall Design Storms: (WSDOE Isopluvial Maps -App. AIII-1.1 of WSDOE Storm Manual) 6 month storm (64% of 2 yr. storm) = 1.28" 2 yr./24 hour storm = 2.0" 10 yr./24 hour storm = 3.0" 100 yr./24 hour storm = 4.0" Post-Development Basin Area Summary Basin "A 1" Basin "A2" Total m ervious Roof 0.09 ac 0.21 ac 0.30 ac mpervious Roadway, arking, Driveways and 0.19 ac 0.51 ac 0.70 ac Sidewalk isturbed Pervious 0.04 ec 0.20 ac 0.24 ac _ Total Developed _ 0.32 ac* 0.92 ac 1.24 ac Area _ _ "1'he above numbers mcmue also ex,aung smc agc uuuwug ,um aua Na.=u o.~a in phase I. i~ Storm water Treatment: ' Basin `Al': Per Stormshed calculations 6 month event will result in peak flow rate of 0.08 cis. ' Runoff will be directed toward catch basins. After storage in underground gallery the runoff will be treated by 24" deep sand filter before infiltration to groundwater. The DOE manual required 6-month even[ to be treated. Treatment of runoff (or storm events up to the 100-year event by passage o(runof( ' through (effectively) a 2-Foot deep sand filter. For treatment requirements of infiltration systems the 1992 DOE manual provides following design criteria: ' Figure III-3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to 12 inches deep. Thus the depth of the sand Slter proposed in this project exceeds the design criteria. ' Runoff will infiltrate through native material below the upper layer soil. DOE Manual requires that runoff from the 6-month, 24-hour storm be treated. This proposal will ' treat runoff from all events up to and exceeding the 100-year, 24-hour event, thus exceeding DOE Manual requirements. Basin `A2': 1 Per Stormshed calculations 6 month event will result in peak flow rate of 0.20 cfs. Runoff will be directed toward catch basins. After storage in underground gallery the ' runoff will be treated by 24" deep sand filter before infiltration to groundwater. The DOE manual required 6-month event to be created. Treatment of runoff for storm events up to the 100-year event by passage of runoff ' through (effectively) a 2-foot deep sand filter. For treatment requirements of infiltration systems the 1992 DOE manual provides following design criteria: ' Figure II]-3.9 in the 1992 DOE manual shows the sand depth (or fabric equivalent) in the filter as 6 to 12 inches deep. Thus the depth of the sand filter proposed in this project exceeds the design criteria. Runoff will infiltrate through native material below the upper layer soil. DOE Manual requires that runoff from the 6-month, 24-hour storm be treated. This proposal will treat runoff from all events up to and exceeding the 100-year, 24-hour event, thus ' exceeding DOE Manua] requirements: 1 1 1 Stormwater Storage and Infiltration: a acit Summa Stora a C Basin ID Impervious Area Includin Roof _ Disturbed Storage Ill Pervious Area Re uired Storage Provided Basin Al 0.28 ac 0.04 ac 350 cf 522 cf _ Basin A2 0.72 ac 0.20 ac 514 cf 2,218 cf TOTAL 1.0 ac I 0.24 ac S64 cf 2,740 cf (1 Based on design iv(iltration rate of 20-inches/hour using StormShed modeling software (or the 100- ' year storm even[ Basins Al and A2: ' See following StormShed softwaze modeling output and spreadsheets for Stormwater storage and infiltration results for basins AI and A2. 1 Appended on: 11:42:22 Tuesday, November 28, 2006 LPOOLCOMPUTE dal] SUMMARY using Puls Start otlive storage: 328.5200 fr Evcat Match Q (cfs) Peak Q (cfs) Peak Stg (ft) Vol (ct) Vol (acft) Time to Empty 100 year 0.0012 0.1 ll 1 329.9390 349.86 0.0080 24.50 100 year Hydiogi aph Plot 025 ~' r/ ~ei dev 'I!l0 geeq _.. ~ •. iv ~ 100 Year hu[ I I. U2 ... ,, ~ __, ' ~ ~-~'~ ~e„1 ;; e a5 e _~~ma~~..~ W T~1iR~E'~~~HOUrs ~~~~«~ ~~ ~rv~ Running C:\\Documents and Settings\\EdM\\My Documents\\al Report.pgm on Tuesday, November 2S, 2006 Summary Report of all Detention Pond Data Eveut Precip (ia) 6 month L2800 2vear 2.0000 10 year 3.0000 100 year 4.0000 ' BASLIST2 [aldev] Using [TYPEIA] As (]00 year] LSTEND BasinID Event ~ PeakQ PeakT Peak Vol Area Method/Loss Rain e tYP ,, (cfs) (hrs) (ao-ef) (ac) al dev 100 0.276] 8 00 '. 0 0946 0 32 SCS/SCS TYPEIA year BASLIST TYPEIA] AS [100 year] DETAILED i~ i~ ' [al dev] LSTEND Record Id: aldev Design Method SCS,.. Rainfall type _ TYPElA HydInri 10.00 min Peaking Factor 484.00 Abstraction Cocff 0:20 . Pervious Area (AMC 2) 0.04 ac DCIA 0.28 ac Pervious CN 80.00 DC CN 98.00 ' Pervious TC 9 39 min DC TC 2.02 min Pervious CN Calc Description SubArea Sub en Open spaces, ]awns,parks (>75% grass) 0.04 ac 80.00 Pervous Composited CN (AMC 2) 8D.00 Pervious TC Calc '. ' Type Description Length Slope Coeff Mis c TT Sheet .Short prairie grass and lawns.: 0.15 50.00 fr 1.00% b.1500 '..2.00 in 9.39 min Pervious TC 9.39 mm Directly Connected CN Calc ' Description SubArea Sub cn Impervious surfaces (pavements, roofs, etc) 0.28 ac 98.00 DC Composited CN (AMC 2) 98.00 Directl} Connected TC Cale Type Description Length Slope Coeff Misc TT Sheet Smooth Surfaces.: 0.011 100.00 ft 1.00% -0.0110 .2.00 m .2.02 mm Directly Connected TC 2.02min HYDLIST SUMMARY [dummy much] [al dev - 100 year] [100 year out] ' LSTEND. _. HydID ,Peak Q (efs) Peak T (hrs) Peak Vol (ao-ft) Cont Area (ac). ' dummy much 0 0012 8.00 0.0003 0.0000 aldev 100 year. 0.2761 8.00 0.0946 0.3200 100 year out 0 1111 '. 7.67 STORLIST [trapal] LSTEND Record Id: trapal i~ Descrip: cb Increment 0.10 ft Start EL 328.5200 fi Max El. 333.0200 ft Length 40 0000 ft Width 6 0000 ft Length ssl '~.0.1Ohav Length ss201000hav Width ss] '.0.1 Ohav 'Width ss2 -0.1000hav Dnly consi der bottom area fox infiltration DISCHLIST [infiltrational ] LSTEND Record Id: infiltrational 0.0946 o.~zoo Descnp: gallery Increment -0.10 fr ', Start EI. 3285200 ft .Max EL :341.0000 fr :Infiltration rate 20.0000 in/hr' WP Multiplier' 1.00 LPOOLCOMPUTE [a2] SUMMARY using Puls Start of live storage: 328.5200 ft Event Match Q (cfs) .Peak Q (cfs) Peak Sfg (ft) Vol (ct) Vol (acft) Time to Empty'. 100 ycar 0.0012 0.4722 329.0197 514.13 '. 0.0118 24.50 Gi ,. .' ,' 0 n rv m .. m m n ~- m T Nine in Hoer T~~ ~~ ~~ rv rv n rv n~ Running C:\\Documents and Settings\\EdM\\My Documents\\a2 Report.pgm on Tuesday, November 28, 2006 Summary Report of all Detention Pond Data Event ~Precip (in) b month 1.2800 2 year 2 0000 10 year .3.0000 100 yeaz 4.0000 BASLIST2 [a2dev] Using [TYPEIA] As []00 year] LSTEND BasinlD Event Peak Q Pcak T (cfs) (hrs) a2de~ 700 ''0.7559 8.00 ycar Peak Vol Area Method/Loss Raintype (aocf) (ac) i 0.299 0.92 SCS/SCS TYPElA' BASLIST [TYPEIA] AS (100 year] DETAILED [a2dev~ LSTEND I 1 Record Id: a2dev ' Design Method SCS Rainfall type TYPElA Hydlnri 10.00 min :Peaking Factor 484.00 .Abstraction Cocff 0.20 Pervious Area (AMC 2) 0.20 ac DCIA 0.72 ac Pervious CN 80.00 DC CN 98.00 Pervious TC 9 39 min DC TC ~~ 2 67 mm Pervious CN Calc ' Description SubArea Sub cn :. Open spaces, lawns,parks (>75% grass) 020 ac 80.00 Pervious Composited CN (AMC 2) 80.00 Pervious TC Calc ' Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lavms.: 0.15 50.00 ft L00% 0.1500 '.2.00 in 939 min Pervious TC 9.39 min Directly Connected CN Calc ' Description SubArea Sub cn Impervious surfaces (pavements, roofs, etc) ' 0.72 ac 98.00 DC Composrted CN (AMC 2) 98 00 Directly Connected TC Calc ' Type Description Length Slope Coeff Misc TT Sheet Smooth Surfaces.: 0.011 100.00 ft i.-0.50% -0.Ol 10 .2.00 in x.67 min Directly Connected TC 2 67mm HYDLIST SUMMARY [dummy much] [a2dev - 100 year] [ 100 year out] ' LSTEND _ HydID Peak Q (cfs)',Peak T (hrs) Peak Val (xe-fr) Cont Area (ac) ' dummy much 0.0012 8.00 0.0003 0.0000 00 02599 0 9200 7559 8 0 a2dev - 100 year . . . .100 year out 0 4722 7.67 02599 0.9200 ' STORLIST 1 1 [trapa2] LSTEND Record Id: trapa2 Descrip: cb ''...Increment ''-0.10 fr Start EL 328.5200 fr Max EI. 333.0200 ft Length 170.0000 ft Width 6 0000 ft Length ssl 0.1 Ohav Length ss2 O.1000hav Width ssl -0.l Ohav Width ss2 -0.1000hav Onlv consider bottom area for infiltration DISCHLIST [infiltrationa] LSTEND Record Id: infiltrational _..__ Descrip ..gallery '.Increment 0.10 ft Start El. 328.5200 ft Max El. 341.0000 ft Infiltrarion rate 20.0000 in/hr WP Multiplier 1.00 Licensed to. KPFF, Inc. -Olympia SCA Consulting Group Stormwater Storage 1 1 /2 812 0 06 INFILTRATION GALLERY A1: Description, Burnett Road Phase2 Date: ##f#3#7f## Job#. 04073 _. For design purposes a 20 in/hr inflUation rate was used to tletermine minimum storage requirements 1 1 1) Minimum Stormwater Storage Volume Required According to StormShed: Vmin = 350 cf 2) Stormwater Storage Volume Provided: Total gallery storage capacity using 3:1 void ratio: V=N[(L"(W'H-Apipe))`0.3+(gpipe`L)]= 522 cf Storage Volume= 522 cf>Required Volume= 350 cf Therefore is Atlequale. 3) 48-Hour Drawdown: Volumeinfltrated= '19,200 cf/48hrs> 350 cf Therefore is Adequate. The requiretl volume of 350 cf will be stored antl infiltrated usin 1 under round infltration tlrainrock allery(ies) 40 ft. long x 6 N. wide x 4.5 ft. tleep with ~ft. diameter perforatetl pipes. ' SCA Consulting Group Stormwater Storage 1 112 812 0 0 6 INFILTRATION GALLERY A2: Description'. Burnett Road Phase 2 Date: ######## Job#'. 040]3 For design purposes a 20 in/hr infltration rate was usetl to tletermine minimum storage requirements 1) Minimum Stormwater Storage Volume Required Accortling to Storm Shed: Vmin= 514 cf 2) Stormwater Storage Volume Providetl: The required volume of 514 cf will be storetl and infJfratetl usin 1 untler round infltration drainrock allery(ies) 170 f. long x 6 R. witle x 4.5 ft. deep with 3 ft. tliameter perforated pipes. Total gallery storage capacity using 3:1 void ratio'. V = N[(L'(W'H-Apipe))'0.3+(Apipe'L))= 2,218 cf Stomge Volume= 2,218 cf>Required Volume= 514 cf Therefore is Adequate. 3) 48-Hour Drawdown: Volumeinflfrated= 81,600 cf/48hrs> 514 cf Therefore is Adequate. Appendix II Preliminary Drainage Plan ~ . NOhJNIH6'dM "W~3,1 a'd0?~ 113N?~f19 -. - ... - Nv~d 3i7b'NI0210 au~~ - ~~ a m ~~~ s ~ = =Ne .. -- ~ 3 a ~ ~ " ' ~"'°"~~ :~ "' '~~ ° ~ ' ~ II 3St/Hd dd02~ 113N21f18 _:, .l?JVNIWIl3bd °'°i ~ ~ b..y v. a o: 7mm ~ ~ e° ~o ~ W ~ S i ~ £ ~ c~ °sd s~ S ~~ ~ < Is S ~, F~~ F~~ ~ _ ,~, a~ w=~ w=w _ ~ ~ ~ ~ ~ ~ _._.__ d~~ ~ a i9oo , a ~ ~ ~ $ ~ ~ ~~ ~ , ~~x~rv ~~ ~3~n.~ a ~ 3 ~ E ~ o ~ d w w~~ w~ o o Cu ii . ^ - s --~ ~ ~ ~ ~ ~ i ~/ ~ ~ ~ ~ A ~ ~ .' ~~ i ~ Q ~ ~ ~ ~ ~ oes iY ~~_. A ~ ~ ~ ~ r ~~, J r ~ ~~ ' i~ ~~ Q ~ „A n ~ '~ A ~ . /l/ ~ A ~> l ~ ~ ~~ ~ ~ ~ ~ ~ p' ~~Z ~ ~, C A -~~V ~ ~ 1 OZN / m ~~ 1 ~.. ~ - ~ ~ ~ i , ~ ~ ~~ ^~ _~ ~r~w y ~ ~ - ~ ~~ „- „~ ~ Q ~ ~; O ~ i ~ ` ~ +r ~ vwi I . ~ ~ ~ ~ ~ - ~ ~ ~ a°°__-__ ; W i li ~ hp Z ~ N 1 II '~\ 4W\ n / `' ~ m nn ~ \ ld ~ ~ m ~ ~ ~ ~ ~ i _. ~~_ I~ 0 m \ ~ ~ _ \ ~ ~ ~ i~; ~~ _ n ~~ ~~ I~~- V ~ ~ i ,- ~~ ;~ ~ ~ ~^ ~~ \j ~ ~ I V ~_ _ :a• ' ~' ~ ~~ ©~ `~ -- ~ ~ - ~' ooGa / I M ~ ~ m o~° ao ,m ~ \ vm ` "~ _ m ~~ V_ ~~{~ ~ ~ ~ ~ ~ h \ _ / ~ m °r ~ M~a 9m M - ~ _M __ .; voa 113Nana~ _~ -_ - n ~. -~ - > n SCF r ~ ,. fr~C ~ bff ~ m~~ s~ r 1 i 1 i Appendix III FEMA FIRMMap s u v. C m a m ,;; ~ ~ m o O ° ' Q i W = ~ tD ~ Q ~+. Z ti0 W .--1 ~ W V C C Z O = M ~ ~ e0 ~ W `~ F. ~ W ~ C u'f iU ~ ~' N_ 6 O F• O U ~ a ~ ,y ~ a o = C 7 Z °~ w , e s , z o w z ~ O~ C ~ o v a o c ~ o >- .a ~ ~ ,~ a v c A ® ~ ~ W i ~ x ~ _ err, v s 6` >~ c ~ I~ i~ B ~-- ~~ ~, J WI Q Q o~ 1 I 1 Appendix IV Facility Summary Forms THURSTON REGION FACILITY SUMMARY FORM Complete one (1) for each facility (detentiodretentioq coalescing plate filter, etc.) on the project site. Attach 8 1/2 x 11 sketch showing location of facility. Proponent's Facility Name or Identifier (e. g., Pond A): See Par( 6 Name of Road or Street m Access Facility: Burnett Rd Hearings Examiner Case Number: Development Rev. Project No. /Bldg Permit No.: farce[ Number: 21713340600 To be completed by Utility Staff: Utility Facility Number Project Number (num) Parcel Number Status: (num, lch) Q Known; 1, Public; 2 Unknown; 3, Unassigned Basin and Subbasin: (num, 6ch) (2ch for basin, 2ch for sub basin, 2ch Curare) Responsible jurisdiction: (alpha, leh) Part 1 - Proiect Name and Proponent Project Name: Burnett Road Commercial Park LLC Projec(Owner: Burnett Raad Commercial Park LLC Project Contact: Burnet! Road Commercial Park LLC Address: 4200 6Ave. Suite301 Lacey WA Y8503 Phone: /3601923-9h55 Project Proponent: Qfd~erentJ Same Address: Same Phone: Same Project Engineer: Firm: 3CA Cnnerdting Croy~q Phone: /3h0)493-h007 Part 2 -Proiect Location Section Township Range ]E Part 3 - Tvoe of Permit Aoolica[ion Type of permit (e.g, Commercial B/dg): Commercial Building Other Permits (circle) ^DOF/W PIPA ^COE 404 ^COE Wetlands ^DOE Dam Safety ^FEMA ^Fdaadplain ^Shoreline Mgmt ^Rockety/Retaining Wal! ^Encroachment ®Grading ^NPDES ^Other Plumbing, Electrical, U[ility Other Agencies (Federal, State, Local, etc.) that h ave had or wild review this' Drainage Erosion Control Plan: N/rl Part 4 -Proposed Proiect Description What stream basin is this project in leg., Percival, Woodland): Nisqua/ly River Project Size, acres 098 Zoning C-1 Onsite: Residential Subdivision: N/A Number of Lots: Lot size (average), acres: Building Permit/Cammercial Plat Building(s) Footprint, acres: 0.21 Concrete Paving, acres: 0.57 Gravel Surface, acres: 0 Lattice Block Paving, acres: 0 Public Roads (including grave! shoulder), acres: 0 Private Roads (including sidewalks), acres : 0 Onsite Impervious Surface Total, acres: 0.78 Part 5 -PreDevel~ed Project Site Chpracter_stics Stream through site, y/n: No Name: DNR Type: Type of feaNre this facility discharges to (i.e., lake, stream, intermittent stream, pothole, roadside ditch, sheetflow to adjacent private property, etc.): Infiltration into ground Swales, Ravines, y/n: No Steep slopes, (steeper than IJ%) y/n: No Erosion hazard, y/n: No 00 yr Flaodplain, y/n: Na Lakes or Wetlands, y/n: No Seeps/Springs, y/n: No High Groundwater Table, y/n: No Wellhead Protection m' Aquifer Sensitive Area, y/n: Pes Pan 6 -Facility Description - Underground Infiltration Gn((erv A2 Total Area Tributary to Facility Including Offsite (acres): 092 Total Onsite Area Tributary to Facility (acres): 0.92 Design Lmpervioa~s Area Tributary to Facility (acres): 0.72 Design Landscaped Area Tributary to Facility (acres): Q20 Design Tota! Tribulary Area to Facility (acrex): 0.92 Eller a one (1) for the type of facility: Wet pond detention Wet pond water surface area, acres Dry pond detention Underground retention 1 Lnfiltration pond Dry well infiltration Coalescing plate separator Centrifti~ge separator Others (pervious pavers w/storage in base layers) Outlet type (Enter a one (L) for each type present) Filler 1 Oi! water separator Single orifice ] Multiple orifices Weir Spl!lway Pump(s) Other (infiltration to groundwater) I Par[ 7 -Release [o Groundwater Design Percolation Rate to Groundwater (ifapp[icab[eJ 20 in/hr 1 1 t r Appendix V Vicinity Map i ~_ ~c~ ~ ~ ! ~i _~ ~ -- _ ----------- o ~ ~i ~ ~ '~ ~- -- ___ ~ ~BUR~ETT RD S~ j ~ ~ - --- ~ ~ ~ ,~^~' ~ ~ ~~ r ~ ~~ ~ ~~~ ~T ~\~~ ~ ~ ~y~ E~ -< I ~ ~~~ A Cn~ tiv~~ ~ ~ r ~ Y D ~ ~~ ~ r~' I ~ ~ ~E ~~ ~ ,,~ ~ ~ ! i I I -i ~~ ~- I ,~_ ~~ ~ ~ I -- ~~ ~ ~i ~n I I ~I ~ ( I I I MOUNTAIN ,IEW ~RD i ~ ~ I I ~I i I ~~ ___ I I i I I I