Groundwater Aquifers | Confined or unconfined?
Confined or unconfined?
Groundwater occurs in two conditions: confined and unconfined. A confined aquiferAn aquifer with a layer of impermeable rock above it where the water is held under pressure. has a layer of impermeable clay or rock above it, and the water is held under pressure greater than the atmospheric pressure. When a well is drilled into a confined aquifer, it penetrates that impermeable, confining layer, allowing the water to rise under pressure. This is called an artesian wellA well in which water is forced out under pressure.. An unconfined aquiferAn aquifer under a layer of permeable rock and soil. has no impermeable layer above it and is usually shallower than a confined aquifer.
[The entire page is 160 words long]