Consider a wide rectangular water channel with a per-unit-width flow rate of 5m³/s·m and a Manning coefficient of n = 0.02. The channel is comprised of a 100 m length having a slope of S₀₁ = 0.01 followed by a 100 m length having a slope of S₀₂ = 0.02.

(a) Calculate the normal and critical depths for the two channel segments. 

(b) Given an initial water depth of 1.25 m, calculate and graph the water surface profile over the full 200 m extent of the channel. Also classify the two channel segments (M1, A2, etc.).

FIGURE P13–90

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