IMPACT OF IRRIGATION ON BRACKISH GROUND-WATER LENSES IN NORTHERN KUWAIT

Kuwait is an arid country with very few natural water resources, Groun d water in Kuwait is mostly saline with some brackish zones existing i n the southwestern region. With an annual average rainfall and evapotr anspiration of about 105 mm and 2270 mm, respectively, recharge of aqu ifers by rainfall is negligible. However, in northern Kuwait, unique g eomorphologic conditions and lithological formations have contributed to the formation of fresh to brackish ground water lenses. Fresh groun d water lenses with total dissolved solids (TDS) less than 1000 p.p.m. were exploited for potable purposes. Brackish ground water with TDS b etween 1000 and 5000 p.p.m. was used for irrigation. Ground water extr action for irrigation has increased gradually since the 1960s and reac hed about 200 Ml day(-1) in 1989, About 30% of irrigated water was los t as evapotranspiration and the rest infiltrated back to the aquifer. As a result, the TDS of ground water at several locations within the f arming region increased to about 8000 p.p.m. in 1989. The maximum decl ine in ground water levels owing to pumping was about 3-5 m in the cen tral farming region. It is estimated that in the next 10 years, if irr igation were to be continued at the 1989 rate, then only about 10-25% of the existing wells will have TDS levels less than 7500 p.p.m.