A weir is constructed across a wide channel to elevate the water level as shown in Figure P15.6. The channel conveys a specific discharge of 3  / s and has a Chezy roughness coefficient of 50...

A weir is constructed across a wide channel to elevate the water level as shown in Figure P15.6. The channel conveys a specific discharge of 3
 / s and has a Chezy roughness coefficient of 50 (metric). Assuming that the water depth at the weir remains constant at 4.5 m, estimate the length of the backwater curve using the direct step method for the following two cases:

(a) The bed slope = 5 cm/km

(b) The bed slope = 10 cm/km