A trapezoidal channel (b= 18 ft, m=2, n = 0.020) conveys 800 cfs down a 0.1% slope toward a free-fall discharge. Assume that channel flow is non-uniform. a) Show with calculations whether flow is subcritical, critical, or supercritical b) At channel flow depths of 4.00 ft and 4.05 ft, calculate flow velocity with both Manning equation and continuity equation