Artesisch

Artesisch, in geology and hydrogeology, describes groundwater contained in a confined aquifer that is under natural hydraulic pressure. An artesian well taps such a pressurized aquifer, allowing water to rise in the well without pumping. If the pressure is high enough, water may emerge at the surface as a fountain.

Etymology and usage: The term artesisch (artesian) derives from the French puits artésien, named for the Artois region in northern France where early wells were described. In English and German, the adjective is used to denote wells or conditions related to this pressurized groundwater.

Geology and mechanism: A confined aquifer lies between impermeable layers such as clay or shale, which trap water under pressure. Recharge areas are typically at a higher elevation than the well site. The hydraulic head in the aquifer creates a potentiometric surface; when a borehole intersects the aquifer, groundwater seeks to reach this surface and may rise above the surrounding ground level.

Distribution and significance: Artesian conditions occur in many regions worldwide where suitable aquifers and confining layers exist. Notable examples include the Great Artesian Basin in Australia, one of the world’s largest artesian groundwater systems, and various wells in European and American basins. Artesian systems have historically provided reliable water supplies for towns, agriculture, and industry.

Uses and environmental considerations: Artesian wells can offer a self-pressurized water source, reducing pumping needs. However, excessive pumping lowers the hydraulic head, which can stop natural artesian discharge, cause drawdown, and lead to subsidence or ecological changes in discharge areas. Sustainable management of recharge and pumping is essential.