GATE 2026 AG – Question 21
A trapezoidal channel carries $5\,\mathrm{m^3/s}$ uniformly. Bottom width is 2 m, side slope 2H:1V, bed slope 1%,and Manning roughness 0.03. Find channel conveyance, in $\mathrm{m^3/s}$.
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Correct answer: (D) 50
Explanation
Manning’s equation can be written $Q=K\sqrt S$,where conveyance $K=AR^{2/3}/n$. Since the discharge and slope are already supplied, no depth calculation is needed. With $S=0.01$, $K=5/\sqrt{0.01}=50$. **D**.