Artesian well

Artesian Well

An artesian well is a type of water well that does not require a pump to bring water to the surface; this occurs when there is enough pressure in the aquifer. The water is delivered to the surface by the natural pressure in the underground aquifer. The term "artesian" comes from the town of Artois in France, the old Roman city of Artesium, where the best known early artesian wells were drilled in the Middle Ages.

History

The concept of artesian wells dates back to the Roman Empire, but the term "artesian" was not coined until much later, in the 19th century. The name is derived from the former province of Artois in France, where many artesian wells were drilled by Carthusian monks from 1126.

Geology

Artesian wells are formed when water is trapped between two impermeable layers of rock such as clay or shale. This water-bearing layer is known as an aquifer. When a well is drilled into this layer, the pressure from the weight of the water above forces the water up the well and to the surface.

Hydrodynamics

The hydrodynamics of an artesian well are complex. The pressure that forces the water from the well is caused by the weight of the water in the aquifer above. This pressure can be measured at different points within the aquifer and is typically reported in terms of pressure head or hydraulic head.

Environmental Impact

Artesian wells can have both positive and negative environmental impacts. On the positive side, they can provide a reliable source of clean water. On the negative side, overuse of artesian wells can lead to a decrease in the water table, causing land subsidence and other environmental problems.

See Also

• Water well
• Aquifer
• Hydrogeology