RETENTION BASIN HYDROGRAPH VOLUME COEFFICIENTS 25- YEAR CURVE
Volume (AF) = 1.25 x Coefficient x Area (AC) (in J - Zone)
Volume (AF) = 1.1 x Coefficient x Area (AC) (in I - Zone)
Volume (AF) = 1.35 x Coefficient x Area (AC) (in K - Zone)
imp* Soil 0% 5% 10% 15% 20% 30% 40% 50% 90% 100%
120 0.014 0.0287 0.0435 0.0582 0.0729 0.1024 0.1319 0.1614 0.2792 0.3087
123 0.0891 0.1001 0.111 0.122 0.133 0.155 0.1769 0.1989 0.2867 0.3087
124 0.0032 0.0185 0.0337 0.049 0.0643 0.0948 0.1254 0.1559 0.2781 0.3087
134 0.0055 0.0206 0.0358 0.051 0.0661 0.0964 0.1268 0.1571 0.2784 0.3087
Land Use DesignationDensityPercent Impervious
NU, RU1 DU/10 Acre, 1 DU/5 Acre10
SR2 DU/Acre30
UR5 DU/Acre45
UMR8 DU/Acre50
UMHR15 DU/Acre65
UHR> 18 DU/Acre75
COM, LI, MICommercial/Industrial90
FIGURE V-9