GREAT ARTESIAN BASIN

also called Great Australian Basin, one of the largest areas of artesian water in the world, underlying about one-fifth of Australia. It includes most of the Darling and Lake Eyre catchments and extends northward to the Gulf of Carpentaria. Most of its 676,250 square miles (1,750,000 square km) underlies Queensland, with smaller segments extending under New South Wales, South Australia, and Northern Territory. Its floor varies considerably in depth, with deepest bores reaching 7,000 feet (2,100 m). The daily free discharge of water, from more than 18,000 boreholes, averages 350,000,000 gallons (1,300,000,000 litres), much of which is lost through evaporation and seepage. Distribution for irrigation, stock, and domestic use is by open earth channels and plastic tubing.