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Home My WebLink AboutBLD2021-00268 - 05 StormwaterApr 29 2021 Apr 29 2021 Apr 29 2021 tpz\ -Z(ag DEPARTMENT OF COMMLTNITY DEVELOPMENT 621 SherideD Street, Pon Townseod, WA 98368 T+ 360.379.4450 I Fex: 360.379.,1451 Web: wwl'.co. ieffetson.q,a,us /communitydevcL)Pmeot E-mail dcd@co.ieffenon.wa.us Scan the QR code to access the digital form STORMWATER CALCUI-ATION WORKSHEE1 D 6o llOO - ltLt rti' I (n rbLPaRcEr#pnortcr/apprtclm uur: DETERM|1{tI{G STORMWATER MANAGEMENT REqUIREMENTS: This stormwater calculation worksheet should be completed first to classify the proposal as "small," 'medium," or "large." The size determines whether 3 Stormwater Site Plan is required in conjunction with a stand-alone stormwater management permit application, building permit application, or other land use approval application that involves stormwater review. The basic information will also be helpful for completing a Stormwater Site Plan, if tnnd4istufting octivity is any activity that results in movement of earth, or a change in the existang soil cover (both vegetative and non-vegetative) and/or the existing soil topography. Land disturbing activities include, but are not limited to clearinS, grading, filling, excavation, and compaction associated with stabilization of structures and road construction. Notive vegetstion is vegetation comprised of plant species, other than noxious weedt which reasonably could have been expected to naturally occur on the site. Examples include species such as Douglas fir, western hemlock, western red cedar, alder, bigleaf maple, and vine maple; shrubs such as willow, elderberry, salmonberry, and salal; herbaceous plants such as sword fern, foam flower, and firmreed. Brdrff s.rc *ytstEel OR d.,3 - REV 5t31l2o19 PARCEL SIZE (I.E., SITE} An acle contains 43,5@ scFrare bet. It/tultiply the acreagE by this figure. OD sq/frSizeofparcelinsquarefeet Size of parcd .!o uq LAND DISTURBING ACTMTY. CONVERSION OF NATIVE VEGETATION' A].ID VOLUIIE OF CUT,FILL 3*o Lawn, landscaping, etc. Driveway, parking, roads, etc. Other compacted surface, etc Temporary construction area Drainfield, septic tank, etc. Total Land DBturbance Cdslate the total area to be deared, graded, filled, excavated, and/or compacGd for pmposed developmer{ projecl. lnclude in this calculation the area to be cleared for: sq/fr sdft sq/ft sqift sqift sqfit sq/ft lndicate Total Volumes of Propoeed: lncludes BMP T5.13 Fill Volume) Cd- Fill curyd) Circle: Yes ArEwer the lollowins tryo queslions related to conlrersion of nati'/e vegE{ation: Does the proied mnvert % acres or more of ndive wgetalion to la{,n or hndscaped areas? Does the proiect con\€rt 2 % acres or more of native vegetation to pasture? Cirde: Yes Consfruction site for strudures 4aF Wdl, utiitbs, etc. _ @ @ t-7 * fr 6l STORTIWATER CALCULATIONS - IMPERVIOUS SURFACE tmp€rvkxts surfue is a hard surface that either prevents or slows the entry of water into the soil as under natural condations prior to development. A hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to roof topt walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving gravel roads, packed earthen materials, and oiled, macadam or other. surfaces which similarly impede the natural inflltration of stormwater. otL /Lq6 7oo 65o TOTAL NEW + TOTAL EXISTING'*This amount v,ill be used to chect tolal lot coverage. sq/ft sqift 2O sqm 2i{(- qot Total New Driveway, parking, roads, etc llEW Sfuctures (all roof area) Sirtraks Patios Sdid Decks without infilfatun bdo ) Driveway, parking, roads, etc other { i P /tL O$et {{t'fr( Total Erisling reM Structures (all rmf area) Sider,lralks Patios Solid Decks withoJt infi lfation below) Divide the total existino impewbus surface above by the size of the parcel and convert to a percentage."7" 4 oh DEVELOPHENT v. REDEVELOPMENT Does the site have > 3596 or more exislino imoervious surface? no yes The proposal as considered redevelopment Answer questions in fuure 2.42- Flory Chart lor Reds€bprnent to determine proiect size (next pagel. Applicants for "small" projects must comply only with Minimum Requirement f2-Construction stormwater Pollution Prevention, Please submit the Small Proj€ct Certification (Worksheet "s). The proponent is responsible for employing the 12 Elements to control erosion and prevent sediment and other pollutants from leaving the site duriflg the construction phase ofthe proiect. Pick up the Construction Stormwate. Pollution kevention (SWPPPI Best ManaSement Practices (8MPsl Fact Shegt. Applicants for "medium" projecls-those that must meet only Mlnimum Requirements f1 through fl5 must submit Worksheet A1 and 81, a stormwater site plan and a construdion stormwater pollution prevention site plan (see Refer€nce AIA and B1A for guidance).). arge" projects-those that must meet all 9 Minimum Requirements- must submit Worksheet Al and 81, a stormwater site plan and a construction stormwater pollution prevention site plan (See Reference A1A and B1A for guidance). Large projects also may require engineering. See Worksheet L to determine additional large proiect requirements. F The proposal is considered new development. Answer questions in Egure 2.4.1 Fbitt Chart for IIeu Development to determine project size (next page). APPIICA T SIGiIATURE By sitning the Stormwater Calculation Worksheet, t as the applicanvow.Er atten that the information proyided herein best o, my knowiedge- I also certily that this application is being made with fhe full knorl€dge and consent qt all wrErs of loll is true and correct to LAxoou/wER G alrIBMD nEptEsarrarv! srGNAt sE,(DArE) sldytu&r 6rc uortstE€t OR 6.b - REV 5/J1/|2019 s{fr 1,104 sq. ft (A.H, 7/22/2021)1,300 sq.ft (A.H, 7/22/2021) 480 sq.ft (A.H, 7/22/2021) 276 sq.ft (A.H, 7/22/2021) 2,056 sq. ft (A.H, 7/22/2021) 1,104 sq. ft (A.H, 7/22/2021) 3,160 sq. ft (A.H, 7/22/2021) no Worksheet S Small Project Certification Permanent and temporary drainage on site is designed to divert Stormwater away from my onsite septic system or any neiBhboring onsite septic system.E B tr tr lvty proposal is a small proiect, which means it will create less than 2,(X)0 square feet of nry, replaced, or Deur plus replaced impervious surface area, and has less than 7,000 square feet of land disturbing activities as defined on the Stormwater Calculation workheet. I undeBtand that my proj€ct must comply with Minimum Requirement #2 in the Department of Ecology Stormr rater Management Manual as amended- I have read the Construction Stormwater Pollution Prevention Fad Sheet and will implement Best ManaBe ment Practices (BMP'5) as applicable to my proiect. Applicant Signature of my knowledge-A//7/es/z"tt taNDowitER oR aurHoRtzED REpRESENTATtvE stGl{ATURE)loarE) This certification may only be used if you answer yes to allofthe questions below {drcle y€s or no}. Otherwise, a submmal prepared by a licensed engineer may be required. no lf located in a Seawater lntrusion Protection Zone (SIPZ), I am able to infiltrate stormwater onsite using a dry- well or other method (full dispeBion, downspout dispersion)- no no By sitning the s.nall p.oject certification, I as the applicanvowner attest t'lat t'E iffomatim provid€d hereh ts true and @nect to the best My proiect will not discharge stormwater runoff into a critical area (including but not limited to: geohazard area or its 3o-foot buffer, wetland or Fish and Wildlife Habitat Conservation Area)