Question

Consider the following statements regarding the conditions to be satisfied for the maximum discharge through a trapezoidal channel section with slope 1: n, bed width b, flow depth d, and having a fixed bed slope:

1. Sloping sides should have an angle of ${30}^0$ with vertical.
2. Hydraulic mean depth equals half the flow depth.
3. Length of sloping sides should be equal to twice the bottom width.

Which of these statements are correct?

• A. 2 and 3
• B. 1 and 2
• C. 1 and 3
• D. 1, 2 and 3

Answer 1

The correct option is B 1 and 2

(b)
The hydraulically efficient trapezoidal channel is half-hexagon. The length of sloping sides will be equal to the bottom width. The sides will ${60}^0$angle from horizontal and ${30}^0$ with vertical.