Until the 1980s, Saudi Arabia had lakes at Layla Aflaj and deep waterholes at 'Al-Kharj, fed by huge underground aquifers formed in prehistoric times and non-renewable. 'Al Kharj was a valuable source of drinking water in a barren terrain. In recent years, these aquifers have been drawn upon heavily, both for agricultural and domestic purposes, and no fresh water remain in the lakes or pits.