What does specific capacity measure in relation to a well?

Specific capacity is a critical parameter in assessing the performance of a well, as it quantifies how effectively a well can yield water in relation to the amount of drawdown that occurs. It is calculated by dividing the discharge rate of the well (the volume of water it can deliver) by the drawdown (the lowering of the water level in the well as water is pumped out).

This measure provides insight into the well's performance, indicating how much water can be produced for every unit of drop in the water level. A higher specific capacity means that less drawdown is needed to achieve a certain yield, suggesting a more efficient well. In contrast, a lower specific capacity implies that significant drawdown is required to extract a given volume of water, which can indicate issues such as reduced permeability of the aquifer or well obstructions.

The other options pertain to different aspects of groundwater and well performance, but they do not specifically define what specific capacity measures. Total water yield refers to the absolute volume of water the well can provide without relating it to drawdown. Overall efficiency may encompass various factors, not just the yield and drawdown. Lastly, the depth of groundwater signifies the vertical distance from the ground surface to the water table, which is unrelated to the