The discharge per unit drawdown at a well is known as
- ASpecific Yield
- BSpecific Storage
- CSafe Yield
- DSpecific CapacityCorrect
Solution
Concept
Definition of specific capacity of well
Formula
NONE
Step-by-step solution
1. Drawdown is the reduction in hydraulic head observed at a well due to pumping. 2. Specific capacity of a well is defined as the discharge rate per unit drawdown. 3. Mathematically, Specific Capacity = Discharge (Q) / Drawdown (s). Answer: D
Explanation
Specific capacity is defined as the rate of discharge from a well per unit of drawdown measured in the well. It measures the water-yielding capability and performance efficiency of a well-aquifer system. Mathematically, it is calculated by dividing the total pumping discharge rate by the resulting drawdown.
Why the other options are wrong
A) Specific yield is the ratio of the volume of water drained by gravity to the total volume of the aquifer. B) Specific storage is the volume of water released per unit volume of aquifer per unit decline in head. C) Safe yield is the maximum sustainable rate of water withdrawal without causing adverse effects.
Shortcut
Specific Capacity = Discharge / Drawdown (Q / s).
Common mistake
Confusing Specific Capacity with Specific Yield, which measures the water volume released under gravity per unit total volume.
Correct answer: D) Specific Capacity