This equation is generally most applicable for turbulent flow on homogeneous surfaces.
Where
-
L, S=see Kerby’s formula
-
i=Rainfall intensity (in/hr)
-
n=Coefficient
|
Typical values for n: |
|
Surface |
n |
|
Asphalt pavement |
0.012 |
|
Concrete pavement |
0.014 |
|
Bare packed soil |
0.020 |
|
Rough bare packed soil |
0.030 |
|
Mowed poor grass |
0.030 |
|
Cultivated rows, no crop |
0.030 |
|
Cultivated row, with crop |
0.040 |
|
Pasture – average grass |
0.040 |
|
Dense grass |
0.060 |
|
Shrubs and brushes |
0.080 |
|
Woods and forests |
0.200 |
|
Land Use |
n |
|
Business |
0.015-0.030 |
|
Semi-business |
0.020-0.035 |
|
Dense residential |
0.025-0.040 |
|
Suburban residential |
0.030-0.055 |
|
Parks |
0.040-0.080 |
|
Light Industrial |
0.015-0.035 |