Dams MCQ with answer and solution

Concept

Spillways are hydraulic structures designed to discharge excess flood water safely downstream without endangering the dam body.

Step-by-step solution

1. Understand the primary function of a dam reservoir, which is to store water. 2. Recognize that during heavy rainfall or floods, excess water enters the reservoir, raising the water level beyond capacity. 3. Identify that spillways are engineered control structures designed specifically to release this excess flood water safely downstream, protecting the main dam from overtopping and erosion.

Explanation

A spillway is a structure constructed to provide the safe release of surplus water or flood water from a reservoir when the water level exceeds its maximum designated limit. It acts as a safety valve for dams, preventing overtopping and potential structural failure.

Why the other options are wrong

A: Reservoir storage is increased by raising the dam height or excavation, not by spillways. C: Sedimentation is prevented or managed using dead storage, silt ejectors, or low-level sluices. D: Flow diversion is typically handled by diversion tunnels or coffer dams during construction.

Shortcut

Think of a spillway as the overflow drain or safety valve of a dam.

Common mistake

Confusing spillways with sluice gates meant for regular irrigation release or sediment flushing.