SW6191003_Calcs (Runoff Coeff.)_20191105

Hobson Road Concrete Plant
Storm Water Control
SCS curve number
Hydraulic Soil Group: A
Area SCS CN
Building (sf)
900
98
Pavement (sf)
97,202
98
Future impervious (sf)
0
98
Open space (sf)
87,226
50
Offsite -open space (sf)
0
50
Offsite -impervious (sf)
0
98
Total (sf)
185328
75
Total (ac)
4.25
Rational Coefficient
Predevelopment
Postdevelopment
Area
C
Area
C
Impervious (sf)
1,869
0.95
Building (sf)
900
0.95
Open space (sf)
183,459
0.30
Pavement (sf)
97,202
0.95
Future impervious (sf)
0
0.95
Total (ac)
185328
0.31
Open space (sf)
87,226
0.30
Total (ac)
4.25
Offsite -open space (sf)
0
0.30
Offsite -impervious (sf)
0
0.95
Total (ac)
185328
0.64
Total (ac)
4.25
1440-Runoff coefficient calcs.xls Printed 11/5/2019