A wide channel consists of three long reaches and has two gates located midway of the first and last reaches. The bed slopes for the three reaches are S1 = 0.008, S2= 0.00309, and S3 = 0.0005. The water discharges to the channel from a lake where the water surface is higher than the normal depth at the inlet. If the discharge is 0.675 m/sec/m, and n = 0.015, sketch the possible water surface profiles in the channel for the following cases: a) The last reach terminates in a sudden fall. b) The last reach discharges to a lake of water level higher than the normal depth at the exit.