What is Artesian aquifer?
[[File:Grube Messel fg15.jpg|thumbnail|right|220px|Artesian well at the [[Messel pit]].]] [[Image:Artesian Well.png|thumb|right|220px|Geological [[stratum|strata]] giving rise to an artesian well.]] [[Image:Artesian Well (PSF).png|thumb|right|220px|Drawing of an artesian well]] An '''artesian aquifer''' is an underground layer which holds [[groundwater]] under pressure. This causes the water level in the well to rise to a point where the pressure is equal to the weight of water putting it under pressure. This type of [[water well|well]] is called an '''artesian well'''. Water may even reach the ground surface if the natural pressure is high enough, in which case the well is called a '''flowing artesian well'''. An aquifer is a [[geologic]] layer which can hold water such as sand and gravel, [[limestone]], or [[sandstone]], through which water flows and is stored. An artesian aquifer is trapped between rocks or clay which causes the pressure. Water returns to the aquifers when the [[water table]] at its recharge zone is at a higher [[elevation]] than the head of the [[water well|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 well]]s are pressurized. ==Origin== '''Artesian wells''' were named after the old province of [[Artois]] in [[France]]. Many artesian wells were drilled there by [[Carthusian]] monks from 1126.<ref>Gies, Frances and Joseph 1995. ''Cathedral, forge, and waterwheel: technology and invention in the Middle Ages''. Harper Perennial, p112. {{ISBN|0-06-016590-1}}</ref> ==Location== There are artesian aquifers in many countries including [[Australia]], the [[USA]], [[Spain]], [[Italy]], the [[United Kingdom]], [[Fiji]] and [[Canada]]. [[Great Artesian Basin|The Great Artesian Basin]] is the largest and deepest artesian basin in the world, occupying 23% of the Australian continent. ==References== {{reflist}} [[Category:Aquifers]] [[Category:Civil engineering]]