What does a confined aquifer typically lack?

A confined aquifer is characterized by being sandwiched between two impermeable layers of rock or sediment. This is what gives the aquifer its "confined" nature, as the surrounding layers restrict water movement both into and out of the aquifer. Unlike unconfined aquifers that are directly open to the surface and can easily receive water from precipitation, confined aquifers are typically isolated from direct water source accessibility, and their recharge is limited to specific areas where the confining layers are either absent or thin.

The presence of impermeable layers above and below the aquifer helps maintain pressure within the aquifer, which can lead to artesian conditions, where water can rise to the surface without the need for pumping. Therefore, the defining trait of a confined aquifer is indeed that it has surrounding impermeable layers, making this understanding pivotal when considering aquifer management and water resource development.