What best defines the term drawdown?

The term drawdown is best defined as the change in water elevation from the normal level to the pumping level. This concept is critical in hydrogeology and well pumping tests. When water is extracted from a well, the water level around the well drops, and this decrease in water elevation—compared to its initial or static level—represents the drawdown.

Understanding drawdown is essential for determining the sustainability of a well's yield and assessing the potential impact of pumping on the surrounding groundwater levels. Analyzing drawdown helps operators manage water resources effectively, ensuring that extraction does not significantly affect the aquifer or the availability of water in the surrounding area. The other options do not encompass this specific definition, as they either refer to static conditions (like the static water level) or aspects of water extraction and replenishment, which are not the same as defining drawdown itself.