What is a confined aquifer?

A confined aquifer is defined as an aquifer that is bounded by impermeable or semi-permeable layers above and below it. These layers, typically composed of materials like clay or solid rock, prevent water from easily moving in or out of the aquifer. As a result, the water in a confined aquifer can be under pressure, which can lead to artesian wells where water rises to the surface without the need for pumping.

The presence of impermeable layers distinguishes a confined aquifer from unconfined aquifers, which are directly connected to the surface and can easily recharge from precipitation or surface water sources. Understanding the characteristics of confined aquifers is crucial for groundwater management, resource development, and environmental protection. The other options do not accurately depict the defining features of a confined aquifer, making the first choice the only correct statement.