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HomeMy WebLinkAboutSD-23-11 - Supplemental - 1200 Dorset Street (15)1S PRE-development 3S Off-site Subcatchment - East of Project 1P CB Existing Eastern CB - Foulsham Hollow Road 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 1S: PRE-development [49] Hint: Tc<2dt may require smaller dt Runoff = 3.47 cfs @ 11.94 hrs, Volume= 0.158 af, Depth= 2.13" 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 34,100 80 >75% Grass cover, Good, HSG D * 4,500 98 Non Permit Ex. Impervious 38,600 Weighted Average 34,100 88.34% Pervious Area 4,500 11.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 200 0.0500 0.91 Lag/CN Method, Subcatchment 1S: PRE-development Runoff Hydrograph Time (hours) 48464442403836343230282624222018161412108642Flow (cfs)3 2 1 0 Type II 24-hr 25-Year Rainfall=3.87" Runoff Area=38,600 sf Runoff Volume=0.158 af Runoff Depth=2.13" Flow Length=200' Slope=0.0500 '/' Tc=3.7 min CN=WQ 3.47 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, 26.97% Impervious, Inflow Depth = 2.39" for 25-Year event Inflow = 7.64 cfs @ 11.95 hrs, Volume= 0.374 af Outflow = 7.64 cfs @ 11.95 hrs, Volume= 0.374 af, Atten= 0%, Lag= 0.0 min Primary = 7.64 cfs @ 11.95 hrs, Volume= 0.374 af Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 412.89' @ 11.95 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=7.63 cfs @ 11.95 hrs HW=412.88' (Free Discharge) 1=Culvert (Inlet Controls 7.63 cfs @ 6.22 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=412.89' 15.0" Round Culvert n=0.013 L=89.0' S=0.0279 '/' 7.64 cfs 7.64 cfs