It is desired to design a trapezoidal channel with a bottom width of 15 ft and 2H on 1 V side slopes. Sieve analyses have revealed a grain size distribution that results in a maximum allowable bed...

It is desired to design a trapezoidal channel with a bottom width of 15 ft and 2H on 1 V side slopes. Sieve analyses have revealed a grain size distribution that results in a maximum allowable bed shear stress of 0.75 lb/ • The channel must be designed to carry a discharge of 1000 cfs at a normal depth of 7 ft.

a. At what slope should the channel be laid?

b. What is the Manning n value for this channel?