A long concrete irrigation channel of rectangular section and base width 3m discharges as a free overfall. The flow is critical at the overfall and the discharge is 0.5m3/s. The channel is on a slope of 1 in 10,000 and has a Manning coefficient of 0.015.
(a) Calculate the uniform and the critical depth.
(b) Sketch and name the particular type of backwater curve occurring in this case.
(c) Estimate the distance along the channel over which the fluid depth changes from 0.4m to 0.2