J_2024 05 09_West Orange Stormwater Management Plan

Pre-Development West Orange with ponds 2 Prepared by TRC Engineers, Inc. Type III 24-hr 2 yr Rainfall=3.42" Printed 3/4/2012 HydroCAD® 9.10 s/n 06401 © 2009 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 6S: EX-DA 6 Runoff = 4.87 cfs @ 12.23 hrs, Volume= Runoff by SCS TR-20 method, Type III 24-hr 2 yr Rainfall=3.42" * * A * UH=SCS, Split 0.494 af, Depth= 1.77" Pervious/Imperv., Area (sf) CN Description 9,501 8,481 43,082 57,041 27.592 98 98 85 80 73 Paved road, HSG D Gravel road, HSG D Yard stone, HSG D Grass cover, Good, HSG D Brush, Good, HSG D 145,697 127,715 17,982 82 80 98 Weighted Average 87.66% Pervious Area 12.34% Impervious Area Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) 13.2 150 0.0500 0.19 Capacity (cfs) Time Span= 0.00-30.00 Description Sheet Flow, Grass: Dense n= 0.240 P2= 3.42" 0:1 30 0.0880 4.45 Shallow Concentrated Flow, 0.2 40 0.3130 2.80 Shallow Concentrated Flow, 0.2 30 0.0330 2.92 Shallow Concentrated Flow, 3.2 240 0.0060 1.25 Shallow Concentrated Flow, Yard Stone Grassed Waterway Kv= 15.0 fps Woodland Kv= 5.0 fps Unpaved Kv= 16.1 fps Unpaved Kv= 16.1 fps 16.9 490 Total hrs, dt= 0.01 hrs