Abstract
Two man-made lakes in the El-Faiyum province of Egypt, formed as reservoirs for agricultural irrigation drainage water, were studied with respect to physical and chemical characteristics. The Wadi El-Raiyan lakes covered an area of about 200 km2 in the Egyptian western desert. Evaporation and a very low rate of precipitation produced a rapid rise in salinity and trace metal content. Salinity ranged from 0.5 g per litre at the inlet to the lakes to 7 g per litre in the seepage area. Water pH was in the range 7.8 to 8.8 (neutral to slightly basic) throughout the system. Heavy metal levels were very low and oxygen and ammonium concentrations were suitable for agriculture. Use of the lakes for recreational activities was also possible.