Gauckler-Manning Equation Formula

Equation for calculate gauckler-manning equation is,

$$V=\frac{\mathrm{k}}{\mathrm{n}}\times \mathrm{R_h^2/3}\times \mathrm{S^1/2}$$

where,
V is the cross-sectional average velocity
n is the Gauckler-Manning coefficient
R_h is the hydraulic radius
S is the slope of the hydraulic grade line or the linear hydraulic head loss (L/L)
k is a conversion factor between SI and English units. k=1 for SI units, and k=1.49 for English units