Design a rectangular channel contraction from width b1 (upstream) to width b2 (downstream). Assume uniform flow approaches the contraction (i.e. normal depth approaching the channel contraction).
Given:
Flow rate = Q = 50,000 cfs
Upstream width = b1 = 100 ft
Downstream width = b2 = 75 ft
Manning’s roughness coefficient = n = 0.012
Invert slope = S0 = 0.005