Question

What is the satisfactory radius for the reverse bottom curve which is provided at the downstream end of the spillway?

(a) One-fourth of the spillway height

(b) Equal to the spillway height

(c) Half the value of the spillway height

(d) One-third of the spillway height

The question was asked in class test.

My question is from Ogee Spillway in portion Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

Correct choice is (a) One-fourth of the spillway height

To elaborate: A smooth gradual reverse curvature is provided at the bottom of the downstream face after the plotting of the profile of the spillway. The curve turns the flow into the discharge channel. The satisfactory radius of the curve is taken as one-fourth of the spillway height.