The quantity of water in a reservoir, which cannot be utilised under normal operating conditions and is stored below the minimum pool level, is known as
- Adead storageCorrect
- Bvalley storage
- Csurcharge storage
- Dlive storage
Solution
Concept
Water stored below the minimum pool level cannot be released for use and is called dead storage.
Step-by-step solution
1. A reservoir has zones: dead storage, useful (live) storage, surcharge storage and valley storage. 2. Water below the minimum pool level (lowest outlet level) cannot be drawn out in normal operation. 3. This unused water is called dead storage. 4. So the answer is (A).
Explanation
Dead storage is the water kept below the minimum pool level. It cannot be taken out through outlets in normal working. It also gives space for silt to settle.
Why the other options are wrong
B: Valley storage is water held in the natural river valley before the dam is built. C: Surcharge storage is water stored above the normal pool level during floods. D: Live (useful) storage is water between the minimum and normal pool levels, and it can be used.
Shortcut
Below minimum pool = dead. Between minimum and normal pool = live. Above normal pool = surcharge.
Common mistake
Mixing up valley storage with dead storage. Valley storage means the natural storage in the river valley.
Correct answer: A) dead storage