Godwin Tract - Godwin Tract runnoff coefficient calcs

Godwin Tract
Storm Water Control
SCS curve number
Hydraulic Soil Group :B&D
Area SCS CN
Building (sf) 0 98
Proposed Gravel (sf) 154,663 98
Open space (sf) 189,374 66
Offsite -open space (sf) 68,147 66
Existing -impervious (sf) 50,754 98
Total (sf)462938 80
Total (ac)10.63
Rational Coefficient
Predevelopment Postdevelopment
Area C Area C
Impervious (sf) 50,754 0.95 Building (sf) 0 0.95
Open space (sf) 412,184 0.30 Proposed Gravel (sf) 154,663 0.95
Open space (sf) 189,374 0.30
Total (ac)462938 0.37 Offsite -open space (sf) 68,147 0.30
Total (ac)10.63 Existing -impervious (sf) 50,754 0.95
Total (ac)462938 0.48
Total (ac)10.63
Godwin Tract runnoff coefficient calcs.xls Printed 2/8/2018