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3 Site Plan - EDP Report ENVIRONMENTAL DESIGN PARTNERSHIP, LLP, 906N. York146C11nenPork,Nr12065 (P1518371.]621 a pllp.�. ,aarg me pfi"�o"l e�w.o�, STORMWATER MANAGEMENT NARRATIVE PROPOSED SITE IMPROVEMENTS FOR SANDERS RESIDENCE TOWN OF QUEENSBURY, NY Prepared by: Environmental Design Partnership Clifton Park, NY 12065 January 2020 Swrmwater Management Narrative Sanders Residence ENVIRIN/MENTM ONION Town of Oueansbum New York ecb PARNERSHIP LLP 1,0 INTRODUCTION The Sanders me proposing a second-floor addition to their two-bedroom residence on an existing 0.45+1-acre parcel.The project site is located to the north west side of Birdsall Road,with frontage on Glen Lake,in the Town of Queensbury,New York. The proposed site improvements will consist of a new second-floor to the dwelling,replacement septic system,new landscaped features and stormwater management devices. The proposed development will result in soil disturbance on the order of 3,895 square feet and the addition of approximately 142 square feet of impervious surface A store water management system will be designed to provide reduction in the stormwater runoff rates and volumes in accordance with the Town of Queensbury Storrnwater Management Regulations. The proposed project is a single-family dwelling resulting in less than 5,000 SF of disturbance with less than 1,000 SF added impervious cover and therefore is not required to gain coverage under NYSDEC SPDES permit. The proposed storinwater management devices will include multiple landscaped garden areas,and one drip edge infiltration trench. This narrative presents a review and comparison of the existing site conditions and proposed site conditions, as well as proposed design concepts to address increased impervious area for the proposed site improvements. The purpose of the stormwater management narrative is to assure that changes in the surface runoff characteristics,as a result of the proposed construction,will not adversely impact adjacent or downstream properties. 2.0 EXISTING SITE CONDITIONS The existing site consists of mostly developed residential type area with a two story wood frame house,three car garage,asphalt drive and parking surface,a well-kept grassed front lawn area, a deck off the rest of the house with a series of steps that traverse down the steep slopes on the western portion of the property to the shoreline of Glen Lake, and a recently renovated dock. The topography of the eastern half of the site(front yard&driveway area)is relatively flat with the steepest slope within the driveway on the order of 4%. This portion of the property appears to drain to the south-western comer of the site, and down Birdsall road. The topography of the western half of the site(house,deck,and shoreline)are steeper with slopes in excess of 30%.A series of steps and retaining walls are featured here to provide access to the shoreline. This portion of the property drains downslope towards Glen Lake. 2.1 Soil and Groundwater Conditions The USDA Natural Resources Conservation Service Soil Survey identifies the two primary soil groups within the area of the proposed site improvements to be Hinckley cobbly sandy loam (HnQ and Hinckley-plainfield complex(HpE).Where the soils onsite consist of sandy loam with large cobbles. The Soil Survey identifies both soil series as Hydrologic Soil Group(HSG) 900 New Yora 146 Clifton Party,NY 12065 (P)518.3T1]021 edpllp.ame Stormwater Management Narrative Sanders Residence ENVIRONMENTAL DESIGN Town of pueenabury New York PARTNPABHIP LLP as "A". Group A soils have a high infiltration rate and consist of deep,well drained to excessively drained sands. Soil test pits were dug on the project site by Redbud Development on November 22,2019 and logged by Environmental Design Partnership. The soils encountered in these pits consisted of brown medium-coarse sand to a depth greater than 72", which are consistent with Hydraulic Soil Group"A"soils. No evidence of seasonal high groundwater was observed in the pits. Percolation tests were also performed on the project site and observed by Environmental Design Partnership.Percolation rates were on the order of 3-4 minutes per inch. 3.0 POST DEVELOPMENT STORMWATER ANALYSIS Site improvements to the property will consist of new second-floor added to the dwelling,a replacement septic system,new landscaped features and stormwater management devices. Stormwater management practices have been designed to provide filtration, infiltration capacity and attenuation of stormwater runoff from the proposed impervious surfaces on the site. The proposed storrrrwater management devices shall include multiple landscaped garden areas, and 1 drip edge infiltration trench. The drip edge infiltration trench will be installed along the eastem and southern sides of the dwelling and will capture runoff from the proposed front porch,dwelling rooftop,and proposed rear screened porch. This device is an improvement from the existing conditions on the project site. Runoff from the existing structure impervious area currently sheet flows to Glen Lake without treatment.The drip edge infiltration will provide filtration,infiltration capacity,and attenuation of stormwater runoff from the rooftop and porches. Also incorporated in the proposed site design is an improved landscaped area located on the steep slopes that lead down to the Glen Lake shoreline. The landscape plans include a number of vegetated areas and improved walls and stairs surrounded by soil beds and plantings that will provide attenuation and promote filtration of surface runoff. These landscape garden areas will use a variation of bioretention with physical filtering and absorption to remove pollutants from the runoff prior to flowing to Glen Lake.The existing shoreline does not feature these improved landscaped areas and therefore these areas will act as an improvement to the existing conditions with the proposed negligible increase in impervious area. 4.0 SUMMARY Development of the proposed site will slightly change the stormwater drainage characteristics of the site;approximately 142 square feet of impervious area will be added and the site will be re- graded and landscaped to support the proposed improvements. Changes to the storrawater drainage characteristics of the site have been evaluated. The proposed Stormwater management devices consisting of drip edge infiltration and landscaped garden areas will comply with the recommendations related to runoff volume and flow rate reduction compared to existing site 900 New York 146 Clifton Park,NY 12065 (P)518.3711621 e0pllp.com Stormwater Management Narrative Sanders Residence ENVIRONMENTAL DESIGN Town of QueensEury,New York PARTNERSHIP LLP conditions. Through the implementation of acceptable stormwater management practices,the proposed project will not adversely affect adjacent or downstream properties. Prepared by: Nicholas Zeglen Reviewed by: Clark Wilkinson,P.E. NO N.York 146 Clifton Park,NY 12DOS (P)518.371.7621 edpllpeom Sturmwater Management Narrative Sanders Residence ENVIRONMENTAL DESIGN Town of puesmalmn,New York ecb PARTNERSHIP,LLP. 5.0 REFERENCES NYSDEC, 1990. "Technical and Operational Guidance Series(5.1.8) Stormwater Management Guidelines for New Development', New York State Department of Environmental Conservation, Division of Water. NYSDEC, 1992. "Reducing the Impacts of Stormwater Runoff from New Development',New York State Department of Environmental Conservation, Division of Water. NYSDEC,2010. "New York State Stormwater Management Design Manual',Center for Watershed Protection,Ellicott City,MD. Rawls, W.J.,Brakensiek,D.L.,and Saxton,K. E., 1982. "Estimation of Soil Properties", Transactions of the American Society of Agricultural Engineers,Vol.25,No. J,pp. 1316-1320. S.C.S., 1988. "Soil Survey of Warren County,New York',U.S. Department of Agriculture, Soil Conservation Service. NO New York 146 Clifton Park.NY 1200 (P(518.371.7621 adalp.con ' fZ ` s.� '41 S * f ,4 C a t � 4 K «ws Stotmwater Management Narrative Senders Residence ENVIRONMENTAL DESIGN Town a QueeneGury,New York ecb MUNERSNIP,LID. Appendix A USDA Soil Survey 900 New York I"Clifton Park,NY 12065 (P)518,371.7621 erplip.com y xyeminglc Sou Gloq 4 ,Ccurny,xv voA a � 14 e s i B 8 warm. 6 y ® xim wneprelmnamy.Os"Haslvm. wm amo mm mm mm m® e� a io a �. LSp xniel xesouices mo Snll survey 11I.Wo �i con"Naion SeMu Nafbnal Lcapxstiun Sall Survey Ppe1 of Nydral Sill Gmtp-mean Comm,Nall lom MAPLEGEND MAP INFORMATION An.of I....Ill c The¢dl¢urve,them oemebey mPOl wet Mot am a1 NUWI"lensl(POq ■ cm 'All a>dvwre O W"ag'.$0,I Me,meymmbe"'b"tlllaspb. aO un p rvanue"rnaunoaen enlegmrentmmep¢b- "Manneleamapoirgcml ceuu o ` Innaunamataram aNaeeteimmapvina and aauary Ma0u aen It Ttwmepa aO nW¢Mw Pa amdl alaesM E] atn,rm ab canal, mno-eaong¢Ou¢Ihd mna ha.:been small m a mot patanea l nammooneunn Ill M ap µa R.IS O N Plamer&y an the bar...00 amen moil Meat M mep IMenMe WpMreR me.....a. ® 0(0 — U6RONen SOvatl Wp: NaW21Rem0ulxee COnaervebm Senom ® O N6b Salsurvey URL eamil0 '. as COONnMSyatem; blab Mavatal(EPSG'.Ilm) Q Notnene-eiawikMe Lml Poet Mearearear bad nam One¢ Meoa Rcm Illimi hhLSoil Survey ere oon masha se Webbate eaagmaM onamemadam pta9R,mMInes Manprem ape wt an,m " n"Irylaonv aipan... .a.n epreannm emidbe alas, me as me +v are "ene1P mom aequal:reamnmpgactiOo aarmabeu¢annmare B[wtb caIaIB4Me IX a6tellm IX elw are reglAretl. N a TIII¢ptauq is minden men M.O50A-N RCs mnlllea d.. ^y eN lime.OnaaleptatWbdux. y C Sail Survry Nee: inenen CouMy,Naw Ywk N cre Survey Amm Data. Vetlonl9,sepie,2019 Sal meD ants ere lebelea(a¢apem elluve)Mmep acelea in 1:50.Oro or met .. nm..,.1 a"l aoaima Deal amen inall wet pbongmpbea: Jun 10,201!--Mar adl ateme P. 292017 ■ A The oMOpnom or Meer babe map on wall the Boll 111 Were Np aomgle]and al91hma pmbabty alMm Man Me ba,mm e, Imagery oneeyed no i.mean.Aa a mal wme I. 9 smmme a map umt wulMenae may ba enact 1 op Matuol Rewurtea Mb soil Survey vt Y102a COnaetallon Service minmt Caomrman,Sell survey the, 14 Hydrologic Soil Group—Warren County,New yolk Hydrologic Soil Group Map unilaymbol Map unit name 111111 Acres in Act Percent of A01 HnC Hinckley mbbty sandy A 0.2 283% loam,8 to 15 percent slopes HpE Hinckley-Plainfield A 04 71.3% complex,steep Totals for Area of Interest 0.6 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups(A, B, C,and D)and three dual classes(AID, BID,and C/D).The groups are defined as follows: Group A. Soils having a high infiltration rate(low runoff potential)when thoroughly wet.These consist mainly of deep,well drained to excessively drained sands or gravelly sands.These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet.These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture.These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate(high runoff potential)when thoroughly wet.These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table,soils that have a claypan or day layer at or near the surface, and soils that are shallow over nearly impervious material.These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, BID,or C/D),the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. tttDp Natural Resources Wab Soil Survey 1/13/2020 i Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Groula—Wanen County,New York Rating Options Aggregation Method:Dominant Condition Component Percent Cutoff. None Specified Tie-break Rule:Higher tSW Natural Re sources Web Soil Survey 1/13QO20 Consorvatlon Service National CooperiaW Soil Suney Page4of4