A trapezoidal channel is to be designed to carry a maximum discharge of 500 cfs through an alluvium with a  of 0.25 in. The channel is to run on a slope of XXXXXXXXXXft/ft and land constrictions are...

A trapezoidal channel is to be designed to carry a maximum discharge of 500 cfs through an alluvium with a
 of 0.25 in. The channel is to run on a slope of 0.0025 ft/ft and land constrictions are such that the bottom width cannot be more than 7.5 ft. Determine if the channel will have to be lined with rip-rap, and if so size the stone for both the bed and sides.