Kinematic Wave Equation

This equation applies to planes of sheet flow of homogenous slope and roughness. Cumulative watershed travel time should be summation of sub-areas with different slopes or overland roughness.

Note: Surface Roughness (n') is similar but not identical to the Manning's n value for the same surface.

T_c	Time of concentration (min)
L	Overland sheet flow path length (m)
n'	Surface Roughness (Retardance Coefficient)
i	Rainfall intensity (mm/hr)
S	Slope (m/m)