Open Channel Flow

A wide rectangular grassed waterway carries flow at a depth of $y = 0.5\text{ m}$ on a bed slope $S = 0.0016$ (so $\sqrt{S} = 0.04$). For a wide channel, the hydraulic radius $R \approx y = 0.5\text{ m}$. If Manning's roughness coefficient is $n = 0.04$, the mean flow velocity in m/s is: (Take $(0.5)^{2/3} = 0.630$)