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HomeMy WebLinkAboutSD-23-11 - Supplemental - 1200 Dorset Street (13)2S POST-development 3S Off-site Subcatchment - East of Project 1P CB Existing Eastern CB - Foulsham Hollow Road 2P Gravel Wetland Routing Diagram for Heald Subdivision - Lot 6 Prepared by Civil Engineering Associates, Inc., Printed 8/29/2023 HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 25-Year Rainfall=3.87"Heald Subdivision - Lot 6 Printed 8/29/2023Prepared by Civil Engineering Associates, Inc. Page 2HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: POST-development [49] Hint: Tc<2dt may require smaller dt Runoff = 4.13 cfs @ 11.93 hrs, Volume= 0.198 af, Depth= 2.68" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 25-Year Rainfall=3.87" Area (sf) CN Description * 21,600 80 >75% Grass cover, Good, HSG D * 12,500 98 Impervious, HSG D * 4,500 98 Non Permit Ex. Impervious 38,600 Weighted Average 21,600 55.96% Pervious Area 17,000 44.04% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.0 200 0.0500 1.12 Lag/CN Method, Subcatchment 2S: POST-development Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Type II 24-hr 25-Year Rainfall=3.87" Runoff Area=38,600 sf Runoff Volume=0.198 af Runoff Depth=2.68" Flow Length=200' Slope=0.0500 '/' Tc=3.0 min CN=WQ 4.13 cfs Type II 24-hr 25-Year Rainfall=3.87"Heald Subdivision - Lot 6 Printed 8/29/2023Prepared by Civil Engineering Associates, Inc. Page 3HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: Off-site Subcatchment - East of Project [49] Hint: Tc<2dt may require smaller dt Runoff = 4.20 cfs @ 11.96 hrs, Volume= 0.217 af, Depth= 2.63" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 25-Year Rainfall=3.87" Area (sf) CN Description 25,595 80 >75% Grass cover, Good, HSG D * 17,540 98 Impervious 43,135 Weighted Average 25,595 59.34% Pervious Area 17,540 40.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.4 370 0.0440 1.14 Lag/CN Method, Subcatchment 3S: Off-site Subcatchment - East of Project Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Type II 24-hr 25-Year Rainfall=3.87" Runoff Area=43,135 sf Runoff Volume=0.217 af Runoff Depth=2.63" Flow Length=370' Slope=0.0440 '/' Tc=5.4 min CN=WQ 4.20 cfs Type II 24-hr 25-Year Rainfall=3.87"Heald Subdivision - Lot 6 Printed 8/29/2023Prepared by Civil Engineering Associates, Inc. Page 4HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Summary for Pond 1P: Existing Eastern CB - Foulsham Hollow Road Inflow Area = 1.876 ac, 42.26% Impervious, Inflow Depth = 2.65" for 25-Year event Inflow = 7.22 cfs @ 11.97 hrs, Volume= 0.415 af Outflow = 7.22 cfs @ 11.97 hrs, Volume= 0.415 af, Atten= 0%, Lag= 0.0 min Primary = 7.22 cfs @ 11.97 hrs, Volume= 0.415 af Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 412.58' @ 11.97 hrs Flood Elev= 415.20' Device Routing Invert Outlet Devices #1 Primary 409.58'15.0" Round Culvert L= 89.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 409.58' / 407.10' S= 0.0279 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf Primary OutFlow Max=7.02 cfs @ 11.97 hrs HW=412.47' (Free Discharge) 1=Culvert (Inlet Controls 7.02 cfs @ 5.72 fps) Pond 1P: Existing Eastern CB - Foulsham Hollow Road Inflow Primary Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)8 7 6 5 4 3 2 1 0 Inflow Area=1.876 ac Peak Elev=412.58' 15.0" Round Culvert n=0.013 L=89.0' S=0.0279 '/' 7.22 cfs 7.22 cfs Type II 24-hr 25-Year Rainfall=3.87"Heald Subdivision - Lot 6 Printed 8/29/2023Prepared by Civil Engineering Associates, Inc. Page 5HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Summary for Pond 2P: Gravel Wetland Inflow Area = 0.886 ac, 44.04% Impervious, Inflow Depth = 2.68" for 25-Year event Inflow = 4.13 cfs @ 11.93 hrs, Volume= 0.198 af Outflow = 3.29 cfs @ 11.99 hrs, Volume= 0.198 af, Atten= 20%, Lag= 3.4 min Primary = 3.29 cfs @ 11.99 hrs, Volume= 0.198 af Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Starting Elev= 420.50' Surf.Area= 482 sf Storage= 449 cf Peak Elev= 423.20' @ 11.98 hrs Surf.Area= 1,211 sf Storage= 2,214 cf (1,765 cf above start) Plug-Flow detention time= 130.1 min calculated for 0.188 af (95% of inflow) Center-of-Mass det. time= 73.2 min ( 851.9 - 778.7 ) Volume Invert Avail.Storage Storage Description #1 418.00' 3,385 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic-feet) (cubic-feet) 418.00 482 0.0 0 0 420.33 482 40.0 449 449 421.00 482 0.0 0 449 422.00 752 100.0 617 1,066 423.00 1,080 100.0 916 1,982 424.00 1,725 100.0 1,403 3,385 Device Routing Invert Outlet Devices #1 Primary 420.50'12.0" Round Culvert L= 160.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 420.50' / 412.50' S= 0.0500 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 418.20'1.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 421.90'10.0" Round Culvert L= 5.0' CPP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 421.90' / 420.70' S= 0.2400 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.55 sf #4 Device 1 423.10'24.0" x 24.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=3.14 cfs @ 11.99 hrs HW=423.19' (Free Discharge) 1=Culvert (Passes 3.14 cfs of 4.41 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.04 cfs @ 7.89 fps) 3=Culvert (Inlet Controls 2.45 cfs @ 4.49 fps) 4=Orifice/Grate (Weir Controls 0.65 cfs @ 0.95 fps) Type II 24-hr 25-Year Rainfall=3.87"Heald Subdivision - Lot 6 Printed 8/29/2023Prepared by Civil Engineering Associates, Inc. Page 6HydroCAD® 10.00-25 s/n 00787 © 2019 HydroCAD Software Solutions LLC Pond 2P: Gravel Wetland Inflow Primary Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)4 3 2 1 0 Inflow Area=0.886 ac Peak Elev=423.20' Storage=2,214 cf 4.13 cfs 3.29 cfs