Question

For a wide trapezoidal channel, the channel index is ______

(a) 2/3

(b) 5/3

(c) 4/3

(d) 1/3

This question was addressed to me in an online quiz.

I would like to ask this question from Regulation Modules in chapter Regulation Modules and Canal Structure of Irrigation Engineering

Answer 1

Right answer is (b) 5/3

The explanation: The discharge is proportional to the y^5/3 for a wide trapezoidal channel. Hence, the channel index is generally 5/3. The discharge through an orifice type outlet is proportional to H^1/2 and channel index for such outlet is 1/2.