Question

The energy dissipation at the toe of the spillway is affected basically by the use of hydraulic jump in _______________________

(a) roller bucket

(b) a ski-jump bucket

(c) a sloping apron below the downstream river bed

(d) both roller and ski-jump bucket

I have been asked this question in a dream while sleeping

Asked question is from Energy Dissipation Below Overflow Spillway in division Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

Right answer is (c) a sloping apron below the downstream river bed

For explanation: Most of the kinetic energy is destroyed by creating a condition suitable for the formation of a hydraulic jump. Sometimes the depth of tail-water may be more than that necessary to create the hydraulic jump. The depth of water can be reduced to create a hydraulic jump by providing a sloping apron.