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HomeMy WebLinkAbout1648H Drainage CalculationsDRAINAGE CALCULATIONS: DEFINITIVE PLAN FOR #55 THACHER.SHORE ROAD, YARMOUTHPORT, MA Date: 7/5/05 down cape engineering inc. 939 Main Street Yarmouthport, MA 02675 PREPARED FOR: DAVID SWIFT SUBDIVISION FOR #55 THACHER SHORE ROAD, YARMOUTHPORT, MA — David Swift Property 7/5/05 DRAINAGE SUMMARY The drainage system specified for the proposed driveway/road for #55 Thacher Shore Road in Yarmouthport has been designed in accordance with DEP Stormwater Management Guideline's recommendations. Site planning techniques were utilized that will minimize runoff per Dept. guidelines. The system utilizes a pervious gravel road surface to lessen runoff. Water which does sheet off the road is dissipated by an open graded top course of gravel, and is collected by shallow grass lined swales along the drive shoulders. The swales will provide the primary infiltration of stormwater. To increase infiltration and lower TSS, v -notch weir check dams are proposed at frequent intervals on both sides of the drive. These checks provide a stilling basin effect on any flow through the swales, and will collect any silt generated by overland flow. The system thus utilizes pervious roadway surfaces, and grass lined swales with check dams to infiltrate the design storm on-site and to achieve the required TSS removal mandated by the State Stormwater Management Guidelines. A typical check dam drainage area was routed through a typical v -notch weir check dam utilizing HydroCAD and a 25 year storm (TR -20, Type III Rainfall) to verify the sizing of the dam. The v - notch allows water to flow through, while storing adequate volume to enhance TSS removal. The frequent intervals of the check dams, combined with the gentler slopes encountered in the center of the drive and towards Thacher Shore Road, will ensure runoff is infiltrated and that silt is contained on site. The site planning techniques utilized will ensure compliance with Stormwater Management Guidelines. The calculations and drainage area sketch plan are attached for reference. SUMMARY: USE THE PERVIOUS GRAVEL SURFACE, SHALLOW GRASS LINED SWALES, AND V - NOTCH WEIR CHECK DAMS AS SHOWN ON THE PROFILE PLANS DATED REVISED 7/05/05 FOR THE PROPOSED DRIVE AT #55 THACHER SHORE ROAD, YARMOUTHPORT. .&"A. �v� P�,�N OF A�ss9c ARA H, c 7 " CIVIL Arne H. Ojala PLS, PE date No. 30792 Down Cape Engineering, Inc.43 sTe�L �SS��N.4! ENG\ DRAINk�E A r�N o Isom SF Subcat Reach on Link 05-003 SWIFT Type 111 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 1 HydroCAD® 6.00 s/n 001910 01986-2001 Applied Microcomputer Systems 7/5/2005 Time span=5.00-20.00 hrs, dt=0.01 hrs, 1501 points Runoff by SCS TR -20 method, UH=SCS, Type III 24 -hr Rainfall=5.70" Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Pond 1P: grass lined swale/check dam Peak Storage= 2 cf Inflow= 0.03 cfs 0.002 of Primary= 0.03 cfs 0.002 of Outflow= 0.03 cfs 0.002 of i 05-003 SWIFT Type //l 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 2 HydroCADO 6.00 s/n 001910 01986-2001 Applied Microcomputer Systems 7/5/2005 Pond 1 P: grass lined swale/check dam Inflow = 0.03 cfs @ 12.05 hrs, Volume= 0.002 of Outflow = 0.03 cfs @ 12.05 hrs, Volume= 0.002 af, Atten= 0%, Lag= 0.2 min Primary = 0.03 cfs @ 12.05 hrs, Volume= 0.002 of Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 33.56' Storage= 2 cf Plug -Flow detention time= 7.4 min calculated for 0.002 of (99% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 33.10 2 0 0 33.50 4 1 1 34.00 12 4 5 Primary OutFlow (Free Discharge) t-1=Sharp-Crested Vee/Trap Weir # Routing Invert Outlet Devices 1 Primary 33.50' 90.0 deg x 0.7' long Sharp -Crested Vee/Trap Weir C= 2.50 N w U 3 0 LL Pond 1P: grass lined swale/check dam Hydrograph Plot 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 0 Inflow ❑ Primary 05-003 SWIFT Type 111 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 3 HydroCAD® 6.00 s/n 001910 ©1986-2001 Applied Microcomputer Systems 7/5/2005 Pond 1 P: grass lined swale/check dam Stage -Discharge 0 1 Discharge (cfs) ❑ Primary Pond 1 P: grass lined swale/check dam Stage -Area -Storage SurfaceMetted Area (sq -ft) 0 1 2 3 4 5 6 7 8 9 10 11 12 0 Surface D Storage 34 -- --- --- - ------- ---------------------- -- 33.95 , . -------------- ---- ------------------ --•-- ........ _...._..-------.._. — 33.9 .-------------------------------- -------. ... ------------------------------------------ 33.85 --------- ----- ------------ -- 33.85 -- -- 33.8 . ..... ....... ...... .. 33.75------------------ ----- ------------------ _------------------ ---- .-33.7 - --------------- -- ----- - ------------- --- '----------------- -- --- 65 ' 3.6 ....... ...... .... ....... ...... --- 9i--- ----- ----- - -------.._-------- ----....._ .55 : X3.5 -------- --- --------- ---------- -------------------------- ----- -------- i.45 ' --------------- ----- ------------------------- -- ------ - --- W33.4 33.35 ' --- --------- ----- -- ----- — -------- 33.3 ----- :---------.._..---- - 33.25 " , ' , -- - --- 33.15 " 33.1 0 1 2 3 4 5 Storage (cubic -feet) 05-003 SWIFT Type /Il 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 4 HydroCAD® 6.00 s/n 001910 ©1986-2001 Applied Microcomputer Systems 7/5/2005 Pond 1 P: grass lined swale/check dam Time Inflow Storage Elevation Primary (hours) (cfs) (cubic -feet) (feet) (cfs) 5.00 0.00 0 33.10 0.00 5.50 0.00 0 33.10 0.00 6.00 0.00 0 33.10 0.00 6.50 0.00 0 33.10 0.00 7.00 0.00 0 33.10 0.00 7.50 0.00 0 33.10 0.00 8.00 0.00 0 33.10 0.00 8.50 0.00 0 33.10 0.00 9.00 0.00 0 33.10 0.00 9.50 0.00 0 33.10 0.00 10.00 0.00 0 33.10 0.00 10.50 0.00 0 33.11 0.00 11.00 0.00 0 33.25 0.00 11.50 0.00 1 33.51 0.00 12.00 0.02 2 33.55 0.02 12.50 0.01 1 33.52 0.01 13.00 0.00 1 33.51 0.00 13.50 0.00 1 33.51 0.00 14.00 0.00 1 33.51 0.00 14.50 0.00 1 33.51 0.00 15.00 0.00 1 33.51 0.00 15.50 0.00 1 33.51 0.00 16.00 0.00 1 33.51 0.00 16.50 0.00 1 33.51 0.00 17.00 0.00 1 33.51 0.00 17.50 0.00 1 33.51 0.00 18.00 0.00 1 33.51 0.00 18.50 0.00 1 33.51 0.00 19.00 0.00 1 33.50 0.00 19.50 0.00 1 33.50 0.00 20.00 0.00 1 33.50 0.00 05-003 SWIFT Type /// 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 5 HydroCAD® 6.00 s/n 001910 © 1986-2001 Applied Microcomputer Systems 7/5/2005 Elevation Primary (feet) (cfs) 33.10 0.00 33.11 0.00 33.12 0.00 33.13 0.00 33.14 0.00 33.15 0.00 33.16 0.00 33.17 0.00 33.18 0.00 33.19 0.00 33.20 0.00 33.21 0.00 33.22 0.00 33.23 0.00 33.24 0.00 33.25 0.00 33.26 0.00 33.27 0.00 33.28 0.00 33.29 0.00 33.30 0.00 33.31 0.00 33.32 0.00 33.33 0.00 33.34 0.00 33.35 0.00 33.36 0.00 33.37 0.00 33.38 0.00 33.39 0.00 33.40 0.00 33.41 0.00 33.42 0.00 33.43 0.00 33.44 0.00 33.45 0.00 33.46 0.00 33.47 0.00 33.48 0.00 33.49 0.00 33.50 0.00 33.51 0.00 33.52 0.01 33.53 0.01 33.54 0.02 33.55 0.03 33.56 0.03 33.57 0.04 33.58 0.05 33.59 0.07 33.60 0.08 33.61 0.09 Pond 1 P: grass lined swale/check dam Elevation Primary (feet) (cfs) 33.62 0.10 33.63 0.12 33.64 0.13 33.65 0.15 33.66 0.17 33.67 0.18 33.68 0.20 33.69 0.22 33.70 0.24 33.71 0.26 33.72 0.28 33.73 0.30 33.74 0.33 33.75 0.35 33.76 0.38 33.77 0.40 33.78 0.43 33.79 0.45 33.80 0.48 33.81 0.51 33.82 0.54 33.83 0.57 33.84 0.60 33.85 0.63 33.86 0.67 33.87 0.70 33.88 0.73 33.89 0.77 33.90 0.81 33.91 0.84 33.92 0.88 33.93 0.92 33.94 0.96 33.95 1.00 33.96 1.04 33.97 1.08 33.98 1.13 33.99 1.17 34.00 1.22 05-003 SWIFT Type 111 24 -hr Rainfall=5.70" Prepared by down cape engineering, inc. Page 6 HydroCAD® 6.00 s/n 001910 © 1986-2001 Applied Microcomputer Systems 7/5/2005 Pond 1 P: grass lined swale/check dam Elevation Surface Storage (feet) (sq -ft) (cubic -feet) 33.10 2 0 33.11 2 0 33.12 2 0 33.13 2 0 33.14 2 0 33.15 2 0 33.16 2 0 33.17 2 0 33.18 2 0 33.19 2 0 33.20 2 0 33.21 3 0 33.22 3 0 33.23 3 0 33.24 3 0 33.25 3 0 33.26 3 0 33.27 3 1 33.28 3 1 33.29 3 1 33.30 3 1 33.31 3 1 33.32 3 1 33.33 3 1 33.34 3 1 33.35 3 1 33.36 3 1 33.37 3 1 33.38 3 1 33.39 3 1 33.40 3 1 33.41 4 1 33.42 4 1 33.43 4 1 33.44 4 1 33.45 4 1 33.46 4 1 33.47 4 1 33.48 4 1 33.49 4 1 33.50 4 1 33.51 4 1 33.52 4 1 33.53 4 1 33.54 5 2 33.55 5 2 33.56 5 2 33.57 5 2 33.58 5 2 33.59 5 2 33.60 6 2 33.61 6 2 Elevation Surface Storage (feet) (sq -ft) (cubic -feet) 33.62 6 2 33.63 6 2 33.64 6 2 33.65 6 2 33.66 7 2 33.67 7 3 33.68 7 3 33.69 7 3 33.70 7 3 33.71 7 3 33.72 8 3 33.73 8 3 33.74 8 3 33.75 8 3 33.76 8 3 33.77 8 3 33.78 8 3 33.79 9 4 33.80 9 4 33.81 9 4 33.82 9 4 33.83 9 4 33.84 9 4 33.85 10 4 33.86 10 4 33.87 10 4 33.88 10 4 33.89 10 4 33.90 10 4 33.91 11 4 33.92 11 5 33.93 11 5 33.94 11 5 33.95 11 5 33.96 11 5 33.97 12 5 33.98 12 5 33.99 12 5 34.00 12 5