Question

Which of the following is a secondary safety arrangement?

(a) Safety valves

(b) Spillway gates

(c) Subsidiary spillway

(d) Energy dissipaters

This question was posed to me in quiz.

This intriguing question originated from Location of Spillway topic in chapter Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

Right option is (c) Subsidiary spillway

For explanation I would say: If at the worst condition the water rises above the maximum reservoir level it will overtop such an embankment. A secondary safety arrangement known as subsidiary dam or emergency spillway or breaching section is generally provided on large dams for the disposal of excess water, especially on earthen and rock-fill dams.