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Drainage Report 001Hidden Park Yelm, WA Preliminary Drainage Report October 2007 Prepared by: OLYMPIC ENGINEERING 300 Deschutes Way SW Suite 315 Tumwater WA 98501 360.705-2474 360.705.2443 fax Chris@olyeng.com www.olyeng.com PRF,I,IMINARY DRAINAGE REPORT Yelm, Washington October 2007 Project Information Project: Prepared for: Contact: Hidden Park John Lubbesmeyer John Lubbesmeyer 1151 East 112t^ Street Tacoma, WA 98445 (253) 537-6370 Reviewing Agency Jurisdiction: Project Number: Project Contact City of Yelm Tami Merriman (360) 958-8496 Project Engineer Prepared by: Olympic Engineering 300 Deschutes Way SW Suite 315 Tumwater, WA 98501 (360) 705-2474 FAX (360) 705-2443 Contact: Chris M. Merritt, P.E. OE Project No.: 0503E Pile Name: 05032ydr.doc ahlirys'~ 'ryOrPg~ PROJECT ENGINEERS CERTIFICATION: I hereby certify that this Cis ~ Z ~ ~ Preliminary Drainage Report for the Hidden ParA Plat iv the City of } m Yolm, WvshivgWV has been prnpared by me or under my supervision and 4 ~~~~ v, meets the ivtentoRhe WSOOE 19923wrmwater Management Manual, q O y ~`~A- °Gt6Tef'° G~c ~ unless noted otherwise, and normal standards of engineering practice. I ES~fOMA4 bN ~ underec nd thatthe jarisdidion does not and will not assomeliabihty for Ahe sufficiency, auitabdity, or pedormanec of drainage [a lilies designed `%P'e E6E6 0~ [or this develo t pmen Table of Contents PART I S'PORM DRAINAGE RF,PORT._ .................... _....... _.__.._......... ....1 SF.CTKIN I - PROPOSED PROJECT 11NSCR[PTION._..........._ ........... ....1 SECTION 2 - F%ISTING CONDITIONS ....... _ ......... ....2 SF,CTION 3 - [NF'ILTRATION RATES I SO71.S REPORT ................._.. _._ `L SECTION 4- R'ELLS ANU SEPTIC SYSTEbIS._ ......................._.__.... ....3 SECTIONS- FUEL TANKS ..... ...... ......... ._.3 SECTION 6- SIJB-BASIN llESCRIPTION ..............................._.....___. ....3 SECTION 7 - ANALYSIS OF 100-YN:AR FLOOD......_.. _....._ ................ ....3 S F.CTION H - AESTHN%CIC CONSIDERATIONS FOR FAC[LITIES_. _... 3 SECTION 0 - DOWNSTRE~VN ANALYSIS ........................................__ .....3 SECTION 10 -COVENANTS, DEDICATIONS, EASEMENTS _______ __.9 SECTION 11 -ARTICLES OF INCORPORATION__._ ........... .... ...._._ .._ 4 PART II EROSION CONTROL REPORT ............................................... .....5 SECTION 1 - CONSTRUCTION SEQUENCE AND PROCEDURE ..... ..... u SECTION 2- TA4PPING SEDIMENT ..._...... .___ .. _.5 SECTION 3 - PERhIANEN'L EROSION CONTROL .............._.............. ..... G SECTION 4 - GEOTECIIMCAI. ANALYSIS AND RF.FORT ................ .....0 SECTION 5 - INSPECTION SEQUENCE ....................._.._........... _...... ..... G SF;CTION 6 - CONTROL ON' POLLUTANTS......._.._............_ ............. ......7 PART III MA[NTENANOE PLAN SECTION 1 - REQUIRED b7.4INTENANC6 .............................. ................. % SECTION 2- RESPONSIBLE. ORGANIZ9TION......._. _..._ ..... ............... ltl SECTION .3- VEGETATION hL4NAGEMENT PLAN ............... ............_. IH SECTION 4- SOURCE CONTROL__ ..._..._ ..... 1H :1PPENDICES Appevdix 1~ PreRmivary Dvainagc Calwlativvs APPendix 2- Vicivity Map Appendix 3 - llveivage Ba»iv Map Appevdix 4 ~ Soils Report ii PART I STORM DRAINAGE REPORT SECTION 1 -PROPOSED PROJECT DESCRIPTION Prepared for: John Lubbesmeyer Contact: John Lubbesmeyer 1151 East ] 12~h Street Tacoma, WA 98445 (253) 5:57-6370 Parcel Number: 22719`L 10403 Total Site Area: 4.59 Acres 'Coned: K-6 Site Address: 714 Crystal Springs Rd. NW Yelm, WA 98597 Required Permits: Grading, Utility, Building, etc Section, Township, Range: Section 19 'township 17 North Range 2 East, W.M. Project Overview The project site is located to the east of Crystal Springs Kd. NW in Yelm. The applicant proposes to construct a new public roadway through the parcel connecting to Crystal Springs Rd. NW and Woodland Ct. SE, and to install utility services to serve 19 single family lots. The development will he constructed in one phase. Constriction will include clearing and grading of the site, storm drainage improvements, underground utilities, and paving. City of Yelm sanitary sewer and water mains will be extended into the situ to provide services to the residential lots. Stormwater facilities will be constructed that consist of a proposed wet vault for storm water treatment along with StormTech chambers for retention and inSltration of etormwater runoff created by the new development. See preliminary calculations in Appendix. Stormwater Treatment: All Stormwater runoff 6rom the new roadway will be collected in a aeries of catch basins and conveyed to a wet vault for treatment. The proposed wet vault exceeds the minimum WSDOE requirements. See Preliminary Drainage Calculations in Appendix. stormwater Storage: llischarge from the wet vault will overflow into StormTech chambers for stormwater retention and infiltration to groundwater. 'fhe proposed StormTech chambers exceod the minimum storage requirements per the WSDOE. See Preliminary Drainage Calculations in Appendix. Roof Runoff: RooF runoff from each residential home will be tightliced to individual lot infiltration drainrock drywells. The drywells shall be sized to accommodate 125 cf of storage volume per 1,000 sf of roof area. SECTION 2 -EXISTING CONDITIONS 'l he project site wntxins a single family residence that will remain. All other structures will be demolished. Site relief is nearly level. The terrain slopes away to the cast and west from the center of the parcel. Elevations range from a high of 335-feet at the center of the site to a ]ow of 331-feet at the northeast property corner. Site distinguishing features include a fabric lined fishpond at the southern end of the site and an existing domestic well at the northern end of the parcel. Site vegetation consists of cropped field grasses and three fir trees on the northern half of the site and maintained lawn with landscaping nn the southern half. The project site is bounded by residential property to the west, undeveloped property to the north, and developed commercial property to the east and south. See Section 6 for description of off-site drainage to the property, if any. The project site is located in xn aquifer sensitive area based on review of Thurston County Comprehensive Plan Map M-8. This project will comply with the stormwater treatment requirements of the DOE Manual. SECTION 3 -INFILTRATION RATES /SOILS REPORT The Natural Resource Conservation Service (NRCS) soil survey of Thurston County classifies the on-site soils as Spanaway Gravelly Sandy Loam (Hydrologic Group A). Soil testing by Parnell Engineering confirmed the Spanaway aeries classification. 'Three test, pits were excavated by backhoe to a depth of 144" below the existing grade. One double ring infiltration test was completed in test pit # 2 at 80" below the existing grade. Test pit soil log data sheets and infiltration Lest results are 2 included in the Appendix of this report. SECTION 4 -WELLS AND SEPTIC SYSTEMS No off-site wells were located within 200-feet of this project. An existing on-site well will be decommissioned prior to final project approval. A septic system currently servee the existing home. This will be abandoned per Department of Health standards during development. Water and sanitary sewer services for the proposed project will be provided by the City of Yelm. SECTION 5 -FUEL TANKS No fuel tanks were located during our site inspection or soils work The latest "LUST" list (Leaking Underground Storage 'Dank) was reviewed and no listing for the subject site was found. SECTION 6 -SUB-BASIN DESCRIPTION The project site is located within the Yelm Creek Drainage Basin per the Thurston County Geodata Center. From our site visit there were no signs of existing drainage swales or channels on the proposed property. There did not appear to be a significant amount of ofL site mnoff onto the site from adjacent properties. Hazardous material handling or transportation ie not expected in the area tributary to the on-site detention facility. SECTION 7 -ANALYSIS OF 100-YEAR FLOOD This site does not appear to be located within a Flood plain. SECTION 8 -AESTHETIC CONSIDERATIONS FOR FACILITIES All disturbed pervious areas including the storm drainage and open space tract will he vegetated and landscaped. SECTION 9 -DOWNSTREAM ANALYSIS Preliminary calculations for the project stormwater treatment and storage systems are included in the Appendix of this report. All stormwater runoff generated by site development will be treated, stared, and infiltrated on-site. In the event of a failure, storm water will overflow over into the etorm pipe and catch basin. Adjacent properties should not be affected due to failure of the proposed stormwater system. SECTION 10 -COVENANTS, DEDICATIONS, EASEMENTS On-site drainage facilities will require routine maintenance. A maintenance agreement will be prepared and finalized prior to final project approval. SECTION 11 -PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION In light of the cesidentia] nature of this project, special covenants covering landscape, maintenance, signage, stormwater and site maintenance may he put in place at the time of final platting. The Owner's andlor their representatives will perform maintenance of these private storm drainage facilities. PART II EROSION CONTROL REPORT SECTION 1 -CONSTRUCTION SEQUENCE AND PROCEDURE Proposed development of the residential property will include site grading and erosion control measures designed to contain silt and soil within the project boundaries during construction until permanent erosion control is in place. Erosion/sedimentation control will be achieved by a combination of structuraUvegetative cover measures and construction practices tailored to fit the site. Beat Construction Management Practices (BMP's) will be employed to properly clear and grade the site and to schedule construction activities. Before any construction begins on-site, erosion control facilities shall first be installed. The planned construction sequence is as follows: 1. Install rock construction entrance. Use 4" to S" diameter spans with 12" minimum depth. 2. Install filter fabric fencing, where appropriate. 3. Construct temporary sedimentation basins, if neceesary. 4. Clear site (grubbing and rough grading). 5. During November 1 through March 31, all disturbed areas greater than 5,000 sf that are to be left un-worked for more than twelve (12) hours, shall be stabilized by one of the following: mulch, sodding, or plastic covering. 6. Install underground utilities (cable, telephone, power, etc.). 7. If applicable, provide catch basin protection by installing filter fabric and hay bales around all inlets to drainage system. 8. After paving is complete, install landscape, sod and/or seed, and mulch all disturbed areas. 9. Maintain all erosion control facilities until the entire site ie stabilized and silt runoffceases. 10. Designate an area fox washing of equipment and concrete trucks to control the runoff and eliminate entry into storm drainage systems. SECTION 2 -TRAPPING SEDIMENT A stabilized construction entrance shall be installed at the entrance to the proposed plat to prevent vehicles from tracking soil away from the disturbed areas. If sediment is tracked onto public roadways, sediment shall, on a daily basis, be swept or shoveled from paved surfaces and not washed down into the roadside storm drainage system. The contractor shall not be allowed Lo leave disturbed areas greater thin 5,000 sC that are to be left un-worked for more than twelve (1`L) hours uncovered during the rainy season from November 1 through March 31. Mulch, sodding or plastic covering will be used to prevent erosion in these areas. During construction, the contractor will also be required to install filter fabric fencing as needed, per the erosion control plan and as directed by the engineer, or City Inspector SECTION 3 -PERMANENT EROSION CONTROL & SITE RESTORATION All disturbed areas will be paved, covered with x building or landscaped with grase, shrubbery or trees. SECTION 4 -GEOTECHNICAL ANALYSIS AND REPORT There are no slopes exceeding 16% on-site, therefore, a geotechnical analyeis was deemed unnecessary. SECTION 5 -INSPECTION SEQUENCE In addition to the normal City inspections, the Project Engineer shall inspect the facilitiee related to storm water treatment, erosion control, storage and conveyance during construction. At x minimum, the 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 L. The conveyance systeme will be inspected after construction of the facility, but before the project is completed to ensure the following are in working order: a. Road Drainage Conveyance System b. Wet Vault c. Storm Tech Chambers 3. The permanent Bite restoration measures should 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 Engineer's Construction Inspection Report Form and Residential Agreement to maintain stormwater facilities. These forms must be completed prior to final public works construction approval. 6 SECTION 6 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS Washout from a concrete truck shall not be dumped into the storm drain, or onto soil or pavement, which carries stormwater runoff. It can be dumped into a designated area to be later backBelled or hardened and broken up for disposal into a dumpster. The Contractor will be required to designate a wash down area for equipment and concrete trucks. PART III MAINTENANCE PLAN SECTION 1 -REQUIRED MAINTENANCE The following pages contain maintenance needs for most of the components that are part of your drainage system, as well as for some components that you may not have. Let us know if there are any components that are missing from these pages. Ignore the requirements that do not apply to your system. You should plan to complete a checklist for al] system components on the following schedule: ].Monthly from November through April. 2.Once in late eummer (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 off the problems you looked for each time you did an iuspection. Add comments on problems found and actions taken. Keep these "Checked" sheets in your files, as they will be used to write your annual report (due in May). Some items do not need to be looked at every time an inspection is done. Use the suggest fiequency at the left of each item as a guideline for your inspection. You may call the jurisdiction for technical assistance. Please do not hesitate to call, especially if you are unsure whether a situation you have discovered may be a problem. ATTACHMENT `A' MAINTENANCE PROGRAM COVER SHEET Inspection Yeriod: Number of Sheets Attached: Date Inspected: Inspectors Signature: A7`TACHMENT "A": MAINTENANCE PROGRAM Maintenance ChecklSst foe Conveyance Systems (Pipes, llitches and Swales) Frequency llrainage J 2edd Problem Conditions To Check For Condibons'fhat Should Exist System Feature MS_ Pipes J Sediment& Amumulatnd _wdimem that Pipe cleaned of all sedvvent and debrs ceede 20%of the diameter debris. of cne vied. M ~ Vegetation Vegetation [hot rodaces free All vegeLifinv removed so water nvcmen[o[watnr through flows Reely. pipes. A J Domeged Prptedice a~ativg is Pipe xepviredmraplaced_ (rusted, beet dvmvged, rust is rmvsing cmehed7 re than 6P%deteriorati~n to any partof pipe. M J Anv dent that signifiranHy Pipe repaired or reptaced_ impedes Oow (Le, daaeases thee ecetion arev of pipe e by mor then lp%)_ M Pipe has major cracks or Pipe repaired oaeplvced. tears allowing groundwater leakage. MS Swales Tash& I)umldng nfyard wastes such Retvove trash and debris and debris ae gase etippings and ~lisposo as prescribed by County brmches inro Swale. Waste Management Section. Unsightly accnmulotion of on-degradable materials uch as glasx plastic, metal, foam and coated paper_ M Sediment Aavmulawd sediment that Swale cleaned of all sediment vnd buildup eeede LO%ol the design debris sotMtit matchcc design. depth. M Vegetation Grasv rover is sparse and Aerete rods and reseed and mulch outgrowing ~eedyorareasare bare arena. Mvintainb ase height mer~grown vergrown with woody atamivimum of ti"fim hest cegemtion. stormwater trevtmenL Hamnve oady growth, remntnur and wed a nary. M Conversion Swale has been filled in or If poseibleospeak with homeowner by homy blocked by shed, wwdpde, and request that Swale area be mtu shmbbery. etc. reswre3 Contact Comryto epmpntihle report DroMem i(np[ rectified volnntarlly. A Swnle does Water stvvda in ewele or A survey may be needed to check not drain [low vebcity is very slow. grades Grades need m be in 1 Stagnation occtvs. range if pnssihle_IIgrade is less than i%, under drains may need to be ins[alled_ If you ere unsure whether a problem exists, plea_w sumac[ the Jnrisdictiov and ask 6r technical aaistenca 10 ATTACHMENT "A" (CONTLNU);D) Maintenance Checklist for Catch Basins and Inlets Frequency Drainage JRegd Problem Conditions To Check Fm Condtinns That Should &xist System N'eature M,S General J Trash Trash or deh~ia iv Govtof the No wash or debris located debris, and retch basin opening is blocking mediately in Gont of retch sediment capanry Ly more than lU%_ basin opening. Grate is kept or eo clean and allows water to bve enter. M J Sedimevt or debris (iv the No sediment or debris in the besio)that exmnds V3 the catch basin. Catch basin is depth Gom the bottom n[basin dog out and clean m iwert of the loweet pipe into ovto[the bas n. M,S J 'trash or debris in my inlet nr Inlet and onGet pipes Gee o[ pine bloJdng mom than 1/3 of trash or debris. its nelgnc M J Bupetmal Corner e[Game extende more Frame is even with cmb_ damage to then W4 inch past curb face frame iota the street (d apPlicahle)_ and/or [op slab M J Top elab has holes larger than 2 Top slab is Gee of holes end eyuare ivchea or erveks wider crocks than 1/d ivch (intent ie to make u e all material is mvning into the basin). M J Fram not sitting Bush on top Frame is sitting flash on mp elnb, i.e, eeparetipn n[more slab- than 3H ivch of the Game firm thn enp slab A Cracks in Cracks wider thm tl2 inch and Basin renlamd or mpnircd m basin longer thm 3 fnzt, any evidence design standards- Contact a walls) of soil particles ev[ering oateM1 professional engincur for botwm basin through cracks, or valuation aintevance parson Judges that atrnrmm is pnsonnd_ A J Cracks wider thaw ]l2 inch vvd No cracks mom than ll9 ivch ranger enan l ~t m o,e ioint nr wise at me/oim punlevpntiet any iNetiouWet pipe or any pipe. evidenm o[soil particles entering vetch basin through acks. 4 J BeWement Basin hassettled more thml Basiv replncedor repaired to Imisalign- inch or has rotated more than2 design standards. Contacts ant aches out of aligvmevc professional evgincer 6r valuation. 11 Frequency Draivage Svetem Fevmre Jftey'd Problem Cunditio~To Check Por Coaditioas'fhat Shodd Exist M,S J Fire harard Presevee of chemicals such No color, odor, ur sludge Basin is rather natural gay oil, and Jug out and elem. polloM1iau gasoline Obnoxious mlur. odor, or sludge noted. M,5 J Oodet pipe is Vegetation or roots gn~wiug No vegehatiovnaoot growth dogged with nideUouWet pipe joints preeenG vegeGtioa that is more than a& inches wu and free mans:. iernea avert. If yov are insure whether a vroblem exists, please wnmct We Jnri=dietion end ask fir technical neeistance- Comments l~ A=Annual (Marchm Aprd Dm&acd) M =Monthly (see schedule) 5 = Mcr major storms 12 ATTACHMENT "A" (CONTINUED) Maiuteuance Checklist for Grounds (Landscaping) Fregnen~y Drainage J Problem Conditionsm Chec4 Par Gonditiove That Should Exist S1stem Feature M General Weeds Weeds gmwivg in more M1hap Weeds pmsent in less then 6Y of (nonpoisonous) 20%of the lvndsreped urea the lmrdwnped area~ (trees and shrubs only). M J 63foty havrd Any presence of poiwn ivy nr No poisonous vegetation or other poisonous vegelntim o[ asset nests p2sent in sect nears landscaped area. M,S J Trash or litter Sce Prods Checklist. Sec Pods Checklisk M,S J Erosion oP Noticeahle ells are seen in Causes ofemsmn are identified Ground Surface landscaped areas avd steps taken b slow dow Nspreadnut the water~ Eroded are:cs are filled, wntoured avd seeded. A Trees and J Damage Limbs or parts of trues or Tnm[xees/shmbsmrestore shmbs shmbs that axe split or shape Replace heeNshmba brolen which affect more with severe damagn_ than 2b% of thn total (ofiage of the tree nr shrob_ M J Trees or shrubs that havo Replvnt tree, inspecting lur bmn blown down o. knocked injury w stem or roots. Replan .er. it severely damaged- A J Trecn or ehrubswhitlr aro Plamstakes and robhercoavA not adegmtely.ruppnrted nr fiusaroand young trees/shmba m leaning oveq causing lnr enppart_ exposure oPthe roots If yon are unsure whether a problem exists, please contact the And diction and ask for teehvieal assistance. Comment Kev A= Annoal (binrch or April pm@rrcd) M =Monthly (see echedole) 5 = AR.er major storms ~.~ ATTACHMENT"'A" (CONTINUL~ ll) Maintenance Checklist for Infiltration Systems Frequency nraimge Jnujd Yrnhlem Conditions to Check Por Cooditrnvs That Should F.xist System Feature M,B Genervl J Tmsh& See Mvintnnance Checklist 6r See Maintenance Checklist for debris Ponds- Poods- buildup in pens M J Poisonous See Muinnnmmw Checklist for See Maintenmce Checklist fur vege[etlon Ponds Ponds M,S J Fire See Mvintenance Checklist 6r See Maintenance Checklist for havsrd or PondA Pmde. pollution M J Vegetation See Maintenanw Checklist 6r See Maiotevance Checklist 6r nut rnnaa. Ponce gm ing o[ ergs a M J 2odent See Mvintenanw Checklist for See Maintenance Checklist for holes Ponds. Ponds M J Insects Ses Maintevnnm Checklist for See Maintenance Checklist 6r Pnnds_ Fonda. A Storage J Sediment Asoii texture test indicates Sediment is removed and/or rsa buildup in fariBty is not working at its futility is cleaned so that system designed capabilitres or was i~laefion syswm works correctly desgned_ cording to design. A sediment trapPrn6 area is instaIled to reduce sediment transport into infiltration area q J Btprvge A soil texture test indicatee Additional volume is added futility is nut working at its through excavation mprovide drains designed capabilities or was eeded storage. Soil is aerated elowly cnrrecGy designed. and mtnWled to improve (more than drainage- Contnot the Oiry fur ax nonre) in[ormntlon on its renniremema regvrding excavatra2 vmno..~ M J Sediment Any s diment and debris filling Clean out sump W design happiog en m 10% of depth Gom sump depth rsa bottom to bottom of outlet pips r nhctrncting slow into t}~e ennecu,r vipe_ Ooe Time J SWiment Stormwvter enters infiltration Addatmpping area by trapping roe directly without onstructinga sump 6r settling vat treatment of muds Begregatc settling present ee from rest of GcWty. Contact City for guidance. M Nock filters J Sediment By visual inepectlon little or no Replace gravel in rock filter. and debris water flows through filter dining heavy rain storms S Infiltration J Infiltration Standing Water in Inspection Exrzvate bottom o[treoch as Trenches Failure Weil After a8 home after ssvey but atleast 3feee storm or OveAOw darin Re Ime with crashed mek. 14 Storms CM1eck prelrevtmeot systems [or effectiveness. Oheck tribvtvey area !or sediment If you vre unsure whether a problem exists, please cvvuct the Jnrisdietion and ask 6m tedwral assistanrr- Cummnvts_ XeY A=Novel (March or Aprd pro&rred) M =Monthly (see schedule) 5 = 4f[er major storms 15 ATTACHMENT "A" (CONTINUED) Maintenance Checklist £or Closed Detention Systems (Tanks/Vaults) ~J~ereq. DrainaKC JRega Preldnm copaadapa In Cnaek Por cona;Hona Tnat sbonla Dx;ac s~atem Pcawm M Storage Area J Flogged Air Onc-ha1Po[the cross eec[ion ofa Vevte open mdfvvefioning_ Vents ant is blocked at any point or she xent ie aamaKea_ M Storage Area J Uebds and Accumnlvted sediment depth All sediment end debris Sediment mess t0%oP the diemetu of rowed 6om etornge urea. the storage area For X length of shmalP- vavR or any point aepth coeds ]6%o[diamemr. (lu`xamplc 92~inch storvge tank vu1J inquire cleaning wnen ediment reaches depth of 7 indms 6r more then ]IZ length of tmdJ A Storage Area J Joiv[e Any npemnKS Or voids allowing All joint between taddpipe Between materiel to be transported into eectims ere se~led~ Tavk/Pipe feribty-(Will rnquim Section engine rinF analrais [o deteonme stmcmral emb~ty). A Storage Area J Tmrk Pipe Any part o[tenWpipe le beet oat Tenk/pipe repaired or mplaced Bent Out of of shape mom than Lo°h of its m desg¢ Shope desiKn shape (Review required ny ens Weer m dntermme atmchiral stability} A Sorage Area ~ Vault Cracks wider than V2-inch and Vault mplared or repaired to Strmmm env evidence ofsoil vartides design speoibcatiovs and is Includes entering the strveenre mronKh atrvemrelly eound- oracksin the crocks, or Waq aivtewnrernspewnn Rotmm, pmsonnal aemrmmea mac me Dnmvgc m cult is not stmctmally spuvd. Pra andlor'PoP scan A S[omge Ame J Crocks wider than l/2-inch at No creeks more tnav l/4-inch the joint o[any inlcUwllet pipe wide at the join[o[the any evidence o(_snil particles inlctlonHet pipe. enredns ma narat mroegn me walla A Manhole oover Not Cover cing or only ~ Mannolo 5s closed- in Plvice pertlelly n plats- Any open aMolo regoircs mnin[enance. A Manhole J Locking Mechanism rnmot be opened by Mechanism opaos with prover Mechanism a ainWnance person with cools. Not proper tools- Rolls inm Gamn Working bave. less than t/2 inch of mread (mvY not apply to selGlockinK uaal. n Mavholc J Gwer one mainenance Person cevnot Cover can ne removed and Difficult to ve lld after vpplrmg installed by one maintenance Itemm~e coal lifting pressure. Intent o perrnm i_a m keep coven Gom sevling afi ccess to maintenance. 15 4 req. Dralnvge JReq'd Problem Conditions [o Check Fur Cooditims Thnt Should ExfeL Syetem Peamm A Manhole ladder Ladder is uvsnfe duemmfseivg imdder meets design standards. Nungs ungx, mivaligvmev4 not Allows maintenance perwn sale Unssfe urely auacheJ astruewm ceess- well, mst, or Grads. I[ynu am unsum whether v problem exist, vlease oovmet the Jurisdiefion and ask far techvfcal sss~stnnee. Comments: Key A=Avnuai (March or April prekrredl M =Monthly (see z,:hedoie) S =After major storms 17 SECTION 2 -RESPONSIBLE ORGANIZATION The Homeowners Association shall be responsible for the operation and maintenance of all on-site drainage facilities. SECTION3-VEGETATION MANAGEMENT PLAN All disturbed pervious areas within the site will be landscaped to provide an aesthetically pleasing environment. SECTION 4 -SOURCE CONTROL Warning signs (e.g., "Dump No Waste - llrains bo Groundwater') will be embossed or painted on or adjacent to all storm drain inlets and will be repainted periodically as necessary. 1R Appendix I Preliminary Drainage Calculations PRELIMINARY DRAINAGE CALCULATIONS 'Che following calculations were based on the requirements contained in the WSUOE Stormwater Management Manual, 1992 edition. DESIGN AND BASIN INFORMATION SUMMARY: ~ip< , ,i P„o5k D ~vel'oprrient Ba sin Area Summary (Acre"s~ , ` ° ~:.`- Sub-Basin A Total Impervious Roadway 0.87 0.87 Concrete Sidewalk 0.14 0.14 Impervious Driveway 0.26 0.28 Impervious Roof Area 0.87 0.87 Disturbed Pervious 2.75 2.76 Total 4.89 4.89 Roof Area: 2,000 sfllot Driveway Area: 600 sf/lot Soil Classification: SCS Soil Classification: Spanaway Gravelly Sandy Loam Hydrologic Group: A Design Infiltration Kate: 2d'/hr SUB-BASIN `A' WATER QUALITY CALCULATIONS Minimum Stormwater Treatment Area Required: StormShed software was used to model the runoff from the on-site roadway, sidewalks, and driveway areas- The 6-month storm event resulted in a peak volume of 4,868 cf: 'Phe DOE manual requires that "the permanent pool volume equals the runoff volume from the 6-month, 24-hour design storm. Stormwater Treatment Area Provided: The DOE manual, Section III-4.3.2, requires that "the permanent pool volume equals the runoff volume from the 6-month, 24-hour design storm. Using 4 - 125 LF of 4-foot diameter pipe as a wet vault, with across-sectional area of 10 of at a 3-foot depth, results in an available pool volume of 5,000 ef, which exceeds the required volume of 4,868 cf. See the following SWrmShed modeling output. SUB-BASIN `A' WATER QUANTITY CALCULATIONS *See attached StormShed software output Stormwater Storage Volume Provided: 36 StormTech Chambers: (36)(45.9 cf/chamber) = 1,652 cf Stone Volume w/ 6' Stone Base and 12" Perimeter (30% void ratio): =963 cf Wet Vxult Live Storage Volume: =1,230 of Tot¢l Storage Volume Provided =7,652 of +963 of+7,230 cf = 3,845 cj> 2,673 ej .: OK Active Volume = 2,613 cf (see attached StormShed software output) 24-Hour Drawdown (46' x 30(20"/hr)(1"/12(24 hr) = 55,200 cj> 2,613 cf .: OK ROOF RUNOFF Roof runoff from each residential home will be tightlined to individual lot infiltration drainrock drywells. The drywells shall be sized to accommodate 125 of of storage volume per 1,000 sf of roof area. Olympic Engineering Water Quality - 6-Month Basin A - 6mo Event Summary BasinlD Peak Q Peak T Event ----- (cfs) (hrs) Basin A-6mo 0.34 8.00 Drainage Area: Basin A - 6mo Hyd Method: SCS Unit Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area CN Pervious 0.0000 ac 78.00 Impervious 1.2700 ac 98.00 Tolal 1.2700 ac Supporting Data: Impervious CN Data: Roadway 98.00 Sidewalks 98.00 Driveways 98.00 Pervious T C Data: Flow type: Description: Fixed None Entered Impervious TC Data: Flow type: Description: Shallow Roadway Channel Slorm Pipe Water Quality- 100-Year Hidden Park SfonnS~etl #05032 10131/200] Peak Vol Area Method Raintype (ac-ft) ac /Loss 0.1117 19 SCS/SCS TVPEIA 6mo .. 4,a,s ~f Loss Method: SCS CN Number SCS Abs: 0.20 TC 0.00 hrs 0.18 hrs 0.8700 ac 0.1400 ac 0.2600 ac Lengfh: Slope: Coeff: Travel Time 0.00 ft 0.00 % 0.0100 0.00 min Lenglh: Slope: Coeff: Travel Time 370.00 ft 0.50 % 27.0000 4.29 min 575.00 ft 0.50 % 21.0000 6.45 min RLPCOMPUTE [Pond Level Pool] SUMMARY 100 yr MatchO=PeakO= 1.4870 ds Peak Ou[ O: 0.8857 cfs -Peak Stg: 326.01 ft - Active VoI: 2613.63 cf Summary Report of all RLPooI Data Project Precips [2 yr] 2.00 in [5 yr] 2.50 in [10 yrj 3.00 in [25 yrj 3.00 in [100 yr] 4.00 in [6 mo] 1.28 in BASLIST2 [Basin A] Using [TYPEIA] As [100 yr] LSTEND 1 of3 Olympic Engineering Hitltlen Park S[oimShetl #05032 10I31I200] BasinlD Peak Q Peak T Peak Vol Area Method Event ---- (cfs) (hrs) (ac-ft) ac /Loss BasinA 1.48]0 800 0.8241 4.02 SCSISCS BASLIST [rYPE1A] AS [100 yr] DETAILED [Basin A] LSTEND Drainage Area: Basin A Hyd Method: SCS Unit Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 2.7500 ac Impervious 1.2700 ac Total 4.0200 ac Supporting Data: Pervious CN Data: Landscaping Impervious CN Data: Roadway Sidewalks Driveways Pervious TC Data: Flow type: Description: Sheet Landscaping Impervious TC Data: Flow type: Description: Shallow Roadway Channel Storm Pipe Raintype TYPEIA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.97 hrs 98.00 0.18 hrs 78. 00 2.7500 ac 98 .00 0.8700 ac 98 .00 0.1400 ac 98 .00 0.2600 ac Length: Slope: 488.00 ft 1.00 Length: Slope: 370.00 ft 0.50 575.00 ft 0.50 HYDLIST SUMMARY [Basin A 100-yr out] LSTEND HytlID PeakO PeakT ------- (cfs) (hrs) Basin A 100-yr out 0.89 9.50 STORLIST [StormTech Chambers] LSTEND Node ID: StormTech Chambers Coeff: Travel Time 0.1500 58.12 min Coeff: Travel Time 27.0000 4.29 min 21.0000 6.45 min Peak Vol Cont Area (ac-ft) (ac) 0.8254 4.0200 Desc: StormTech Chambers Start EI: 322.5000 ft Max EI: 326.0000 ft Contrib Basin: Contrib Hyd: Length Width Void Ratio 46.0000 ff 30.0000 ft 54.00 DISCHLIST [Infiltration] LSTEND 2of3 Olympic Engineering Hidden Park StormShed itOW32 10/31/200] Control Structure ID: Infiltration -Infiltration control structure Descrip: StormTech Chambers Start EI Max EI Increment 322.5000 H 349.0000 K 0.10 InFil: 20.00 inlhr Multiplier: 1.00 3 of3 Appendix II Vicinity Map ~. ~ ~ Z K s W n d E w < ~ sn za ~o ~~ ~ u1 ? V m O 3 J O ~ Y a OC Q ~ a z ~ W Z ~ U D ~ S 3 0 an 3 a non 3 '^ '^ .n `v °n°n 0~3 .. oNF z. Appendix III Drainage Basin Map a N ~- ~ S ~~ x to z w n a a W ~ ~ d m N Q Q ~ ~ ~ ~ z O z Z u~ m O Q Q ~ ¢ m O a a Y ~ OC z a y a a z 00 W W ~ ~ c a z = a a 0 3 .. 0 m ~ 3 m ~ yy a N N O O ~' ° 3 0 ~ ovE v o~F {: ~) w Appendix IV Soils Report Crystal Springs Plat Soils Report For Drainage Purposes Site Address: 714 Crystal Springs Road Yelm, WA 98597 Tax Parcel Number: 22719210403 Prepared For: Landshapes Northwest Lnc. 1151 East 112' Street Tacoma, WA 98445 (253)537-6370 Contact: John Lubbesmeyer Prepared By: Parnell Engineering 10623 Hunters Lane S.E. Olympia, WA 985]3 (360) 491-3243 Contact: William Parnell, P_E. PE PARNELL ENGINEERING SOIL EVALUATION REPORT FORM 1: GENERAL SITE INFORMATION PROJECT TITLE: Lubhesmeyer-Crystal Springs Plat SHEET: t OF 1 PROJECT NO. :05152 DATE: 12/19/05 PREPARED BY :William Parnell, P.E. 1. SITE ADDRESS: 714 Crystal Springs Road Yelm, Wa. 99597 TAX PARCEL NUMBER: 22719210403 2. PROJECT DESCRIPTION: Create a 25101 residential subdivision. 3. SITE DESCRIPTION: The 4.99 acre project site is currently occupied by a single residential tlwelling and several outbuildings. Site relief is nearly level. The terrain slopes away to the east and west from the center of the parcel Elevations range from a high of 335 k. at the center of the site to a low of 331 ft. at the northeast property corner. Site distinguishing features include a fabric lined fishpond at the southern end of the site and an existing domestic well at the northern end of the parcel. Site vegetation consists of cropped field grasses and three fr trees on the northern half of the site and maintained lawn with landscaping on the southern half. The project site is bounded by fully developed residential property to the west, undeveloped property to the north and developed commercial property to the east and south. Access is off Crystal Springs Road SE byway of a 40 R. strip of property. On-site soils are swell-drained Spanaway series formed in glacial oulwash. 4. SUMMARY OF SOUS WORK PERFORMED: Three test pits were excavated by backhoe to a depth of 144" below the existing grade. Soils were inspected by entering and visually logging each test pit to a depth of four feet. Soils beyond four feet were inspected by examining backhoe tailings. One double ring infltration test was completetl in test pit #2 at 80" below the existing gratle. Test pR soil log tlata sheets and a double ring infltration test result are included in this report. 5. ADDITIONAL SOILS WORK RECOMMENDED: Additional soils work should not be necessary unless drainage infiltration facilities are located outside the general area encompassed by the soil test pits. 6. FINDINGS: The Natural Resource Conservation Service soil survey For Thurston County mapped the on- site soils as a Spanaway Gravelly Sandy Loam (110). The three test pits confirmetl the Spanaway designation generally profiling a gravelly fine sandy loam surtace soil overlying an extremely gravelly & cobbley coarse sand substratum. The substratum gravels and sands were slightly to moderately loose. Winter water table was not present and indicators were not visible. A double ring infiltration test completed at BO" below the existing grade in test pit #2 yielded an infltration rate of 432 in/hr. 7. RECOMMENDATIONS: The Spanaway soil series is a somewhat excessively drained soil that formed in gravelly glacial outwash. Infiltration rates ate generally rapid in the substratum soils. The specified substratum C-horizon soils should be targeted for all drainage infiltration facilities as noted in the attached soil log data sheets. A design infiltration rate of 20 in/hr or less woultl be appropriate for these targeted soils. During construction, care must betaken to prevent the erasion of exposed soils. Drainage facility infiltration surtaces must be properly protectetl from contamination by the fine-grainetl upper horizon soils and from compaction by construction site activities. Soils not properly protectetl will cause drainage infltration facilities to prematurely fail. I hereby certify that I prepared this report, and conducted or supervised the pertormance of related work. I certiy that I am qualified to do this work. I represent my work to be complete an accurate within the bounds of uncertainty inherent to the ractic o its science, and to be suitable for its intended use. SIGNED: Rir ~'"~ DATE: IZII~fOc ` / ~.~ SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Lubbesmeyer -Crystal Springs Plat SHEET: 1 OF 3 PROJECT NO. :05152 DATE: 12/8/05 PREPARED BY :William Parnell, P.E. SOIL LOG: #1 LOCATION: 270 ft. west and 60 ft. south of the northwest property corner. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Spanaway (110) Terrace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GROUP: Glacial Oulwash A/B Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Greater than bottom of hole Greater than bottom of hole Nearly Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Minimal Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Use a design infiltration rate of 20 in/hr or less for drainage infiltration facilities located in Me C7, C2, C3 and C4 horizon soils. Soils Strata Description Soil Log #1 Horz Deoth Color TexNre A 0"- 15" t0YRZ1 VGrBSiSaLm Bw 15"- 18" fOVR3/6 ExGrSaLm C1 18"- 2]" 10VR5/6 ExGrCSa some stones C2 2]'- 60' tOVRS/6 EvGrBCOb CSa C3 60"-105" 10YRSI6 ExGrCSa C4 105'-144' 2.5V4/1 E%GfD$a %CL %ORG CF STR MOT IND GEM ROO <X> FSP <20 b c40 15BK - - - f1 2E 1 c15 - <]5 SG - - - R 2-6 4 c3 - c85 SG - - - - >20 >40 c1 - <g0 SG - - - - >20 >40 <t - c95 SG - - - - >20 >40 <i - c96 SG - - - - >20 >40 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Lubbesmeyer -Crystal Springs Plat SHEET: 2 OF 3 PROJECT NO. :05152 DATE: 12/8/05 PREPARED BY :William Parnell, P.E. SOIL LOG: #2 LOCATION: 300 k. south and 45 k. east of the northwest property corner. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: Double Ring Infiltration Spanaway (110) Tenace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GROUP: Glacial Outwash A/B Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Greater than bottom of hole Greater than bottom o(hole Neary Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Minimal Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS 8 RECOMMENDATIONS: A double ring infiltragon test completed at 60" below the existing grade yielded an infiltration rate of 432 iNhr. Use a design infiltration rate of 20 in/hr or less for drainage infiltration facilities located in the Ct, C2 and C3 horizon soils. Soils Sttata Description Soil Log #2 Horz De ~ Color TexNre °bCL %ORG CF STR MOT IND CEM ROO <X> FSP A 0'- 2(Y' 10VRZIt VGr6aLm <20 <5 <45 15BK - - - ff 26 1 ewi 20'- 28" 10VR3Y3 VGrSaLm <15 - <50 SG - - - H 2-6 2 eve 28"- 32' 10YRM6 ExGrSaLm <10 - BS SG - - - H 2-6 4 C1 32'- 49" tOVR516 ErGr8COb5a <3 - <86 SG - - - - >20 >40 G2 49'-68" 10VR6/6 Gravel wdb <1 - <96 SG - - - - >20 >40 Santl bintler C3 fi8"-122° tOVRM4 ExGrCSa <t - <g8 SG - - - - >20 >40 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Lubbesmeyer -Crystal Springs Plat SHEET: 3 OF 3 PROJECT NO. :05152 DATE: 12/8/05 PREPARED BY: William Parnell, P.E. SOIL LOG: #3 LOCATION: 610 tt. south and 20 tt. east of Ne northwest property comer. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Spanaway (110) Terrace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GROUP: Glacial Outwash A/B Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Greater than bottom o(hale Greater than bottom o(hole Nearly Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Minimal Slow Minimal 1 i, SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS 8 RECOMMENDATIONS: Use a design infiltration rate of 20 iNhr or less for drainage infiltration facilifies located in the C1, C2, C3 and C4 horizon soils. Soils Strata Description Soil Log #3 Horz Depih Color Texwre °hCL %ORG GF STR MOT IND CEM ROO <X> FSP A 0'- 17" t0VR211 VGrSaLm c20 <6 <20 iSBK - - - H 2-6 1 Bw1 17"- 20" 10VR813 VCOb86t <15 - <66 SG - - - R 2-6 2 saLm Bv2 20"- 24° 10VR3I6 ExGrsaLm '10 - <65 SG - - - ff 28 4 C1 24"- 69" 10VR6/6 EzGrCSa c3 - <g8 SG - - - - >20 >40 C2 69"-78" t0VR616 Gavel wRh q - c99 SG - - - - #0 >40 C6a bintler C3 78'- 96" 10YRSI6 ExGrCSa <7 - <96 SG - - - - >20 >40 C4 98°-144' 2.6Y411 ExGrBCOb <i - <98 SG - - - - >20 >40 Csa Abbreviations Textural Class (Texture) Structure (STR) Grades of Structure Cobble -Cob Granular - Gr Stron - 3 Stone - St Blocky - Blky Moderate - 2 Gravelly - Gr Plat - PI Weak - 1 Sand - Sa Massive - Mas Loamy - Lm Sin le Grained - SG Silt - Si Sub-An ular Block - SBK Cla e -CI Coarse - C Ve -V Extremely - Ex Fine - F Medium - M Induration & Cementation (IND) (CEM) Weak - Wk Moderate -Mod Strong - Str Mottles (MOT) 1 Letter Abundance 1st Number Size 2nd Letter Contrast Few - F Fine - 1 Faint - F Common - C Medium - 2 Distinct - D Many - M Coarse - 3 Prominent - P Roots (ROO) 1st Letter Abundance 2nd Letter Size Few -f Fine -f Common - c Medium - m Many - m Coarse - c <X> -Generalized range of infiltration rates from SCS soil survey (<X>) FSP -Estimated Field Saturated Percolation rate based on horizon specific factors. DOUBLE RING INFILTRATION TEST Crystal Springs Plat Test Date 12/6/2005 Completed By : William Parnell, P.E. PE Job : #05152 DOUBLE RING INFILTRATION TEST Test Hole # 2 (test run @ 80" below existing ground surface ) Start Sto Ela sed Time Total Dro Infiltration Rate ( Min) (Min) (Min) (Inches) (In/Hr ) 0 25" 25" 6 25" 50" 25" 6 50" 1' 20" 30" 6 1' 20" 1' S0" 30" 6 Soaking Period 10' 00" 10' 40" 40" 6 10' 40" 11' 20" 40" 6 11' 20" 12' 00" 40" 6 12' 00" 12' 40" 40" 6 12' 40" 13' 25" 45" 6 13' 25" 14' 05" 40" 6 14' 05" 14' S0" 45" 6 14' 50" 15' 30" 45" 6 15' 30" 16' 15" 45" 6 16' 15" 17' O5" 50" 6 1T OS" 1T 55" 50" 6 1T 55" 18' 45" 50" 6 18' 45" 19' 35" 50" 6 432