Question

Calculate the freeboard for the top levels of the side walls if the mean velocity of water in the chute reach is 3.5 m/s and the mean depth of water in the chute reach under consideration is 4.7 m.

(a) 0.60 m

(b) 1 m

(c) 0.85 m

(d) 0.55 m

This question was addressed to me in class test.

I need to ask this question from Chute Spillway topic in section Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

Correct choice is (c) 0.85 m

For explanation I would say: The freeboard to be provided above the top nappe of side walls is generally given by the equation:

F.B = 0.61 + 0.04 Vm. dm^1/3 where ‘Vm‘ is the mean velocity of water in the chute reach and ‘dm’ is the mean depth of water in the chute reach under consideration.

F.B = 0.61 + 0.04 x 3.5 x 4.7^1/3 = 0.84 m.