Editing Geography of Kuwait (section)

== Geology and aquifers ==
{{main|Geology of Kuwait}}
The land was formed in a recent geologic era. In the south, [[limestone]] rises in a long, north-oriented dome that lies beneath the surface.<ref name=":0" /> It is within and below this formation that the principal [[Oil reserves in Kuwait|oil fields]], Kuwait's most important natural resource, are located.<ref name=":0" /> In the west and north, layers of [[sand]], [[gravel]], [[silt]], and [[clay]] overlie the limestone to a depth of more than 210 meters.<ref name=":0" /> The upper portions of these beds are part of a mass of [[sediment]] deposited by a great [[wadi]] whose most recent channel was the [[Wadi al-Batin|Wadi al Batin]], the broad shallow valley forming the western boundary of the country.<ref name=":0" />

On the western side of the [[Al Rawdatayn]] geological formation, a freshwater [[aquifer]] was discovered in 1960 and became Kuwait's principal water source.<ref name=":0" /> The supply is insufficient to support extensive irrigation, but it is tapped to supplement the distilled water supply that fills most of the country's needs.<ref name=":0" /> The only other exploited aquifer lies in the permeable zone in the top of the limestone of the [[Ash Shuaybah]] field south and east of the city of Kuwait.<ref name=":0" /> Unlike water from the Al Rawdatayn aquifer, water from the Ash Shuaybah aquifer is brackish. Millions of liters a day of this water are pumped for commercial and household purposes.<ref name=":0" />