What does the potentiometric surface represent?

The potentiometric surface represents the level to which water would rise in a piezometer or monitoring well that taps into a confined aquifer. This concept is crucial for understanding groundwater behavior, especially in areas where aquifers are under pressure, meaning the water level in these aquifers is above the top of the aquifer itself. When a well is drilled into such an aquifer, if the water is allowed to flow freely, it will rise to the potentiometric surface, which is determined by the hydraulic head in the aquifer system.

In this context, the potentiometric surface can be thought of as an imaginary surface that extends across the region where water is under pressure, illustrating the potential energy of groundwater driven by hydraulic gradients. This is foundational for groundwater management and understanding how aquifers interact with surface water.

Other options do not accurately reflect the definition of the potentiometric surface. The depth of the water table relates to unconfined aquifers rather than confined ones. The volume of water stored in an aquifer is associated with aquifer capacity, and the pressure exerted by water in a flowing well involves different considerations that don’t encapsulate what the potentiometric surface illustrates.