A rectangular canal with a bed slope 8 cm/km and a bed width of 100 m. If at a depth of 6 m, the canal carries a discharge of 860 m3 /s, find the Manning's roughness, n, Chezy coefficient, C, and the...

A rectangular canal with a bed slope 8 cm/km and a bed width of 100 m. If at a depth of 6 m, the canal carries a discharge of 860 m3 /s, find the Manning's roughness, n, Chezy coefficient, C, and the coefficient of friction,
 Also find the average shear stress on the bed.

Show that for a circular culvert of diameter D the velocity of flow will be maximum when the depth of flow y at the center is 0.81 D. Use the Chezy formula.