Artesian aquifer

:"See Great Artesian Basin for the water source in Australia."

An artesian aquifer is a confined aquifer containing groundwater that will flow upwards through a well without the need for pumping. Water may even spurt out of the ground if the natural pressure is high enough. An aquifer provides the water for an artesian well. An aquifer is a layer of soft rock, like limestone or sandstone, that absorbs water from an inlet path. Porous stone is confined between impermeable rocks or clay. This keeps the pressure high, so when the water finds an outlet, it overcomes gravity and goes up instead of down.

In recharging aquifers, this happens because the water table at its recharge zone is at a higher elevation than the head of the well.

"Fossil water" aquifers can also be artesian if they are under sufficient pressure from the surrounding rocks. This is similar to how many newly tapped oil wells are pressurized.

Origin

Artesian wells were named after the former province of Artois in France, where many artesian wells were drilled by Carthusian monks since 1126. [Frances Gies and Joseph Gies, "Cathedral, Forge, and Waterwheel" subtitled "Technology and Invention in the Middle Ages". Harper Perennial, 1995 ISBN 0-06-016590-1, page 112.] The technique was also known much earlier in Syria and Egypt, [For references on ancient uses, see Michel Wuttmann, [http://www.achemenet.com/pdf/jasr/jasr2000.1.pdf "The Qanats of 'Ayn-Manâwîr, Kharga Oasis, Egypt"] , in "Jasr" 2001, p. 1. and [http://www.carlo-bergmann.de/Discoveries/discovery.htm Discoveries in the Western Desert of Egypt] ] although whether the monks of Artois learned of it from outside sources or discovered it independently is unknown.

Examples of artesian wells

Australia

* The Great Artesian Basin is the largest and deepest artesian basin in the world, occupying 23% of the continent.

United States

Some towns in the United States were named Artesia after the artesian wells in the vicinity. Other artesian well sites include:
* Pahrump, Nevada
* Fountain Point, Michigan
* Olympia, Washington
* Memphis, Tennessee
* Smoke Hole Caverns, Seneca Rocks, West Virginia
* Evamor, Goodbee, Louisiana
* Black Belt (region of Alabama)
* Potomac, Illinois

Canada

* Oak Hills-Stirling,Ontario

See also

* Drinking water
* Fluid mechanics
* Great Artesian Basin
* Hydrogeology
* Qanat

Notes