Question

A siphon spillway is sufficiently independent of the water surface elevation of the reservoir.

(a) True

(b) False

This question was posed to me during an online interview.

This is a very interesting question from Shaft Spillway topic in chapter Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

Right answer is (a) True

For explanation: The discharge through the siphon is given by the equation-

Q = Cd. A. (2gH)^1/2 where Cd is the coefficient of discharge, A is the area of the cross-section and H is the effective head i.e. the difference of the water level in the reservoir and the tailwater level for a submerged outlet. The discharge through the spillway is affected to a very less extent is the water surface in the reservoir rises.