How is a confined artesian aquifer defined?

A confined artesian aquifer is characterized by being surrounded or confined by impermeable layers of rock or sediment that create pressure within the aquifer. This confinement allows the aquifer to store water under pressure, which can lead to the water rising above the top of the aquifer when tapped by wells, a phenomenon known as artesian flow.

The presence of the impervious material from above prevents direct recharge from surface water and contributes to the pressure that allows the water to flow naturally to the surface. This distinct property is what differentiates confined aquifers from unconfined ones, where water can easily infiltrate and recharge from the land surface.

Understanding this definition is crucial for groundwater management, as it influences how water can be accessed and utilized, as well as how contamination might spread. The conditions that define a confined aquifer are important for assessing the sustainability of groundwater sources and implementing suitable conservation practices.