HYDROLOGY AND WATER CHEMISTRY OF LAKE BURDUR, SOUTH-WEST ANATOLIA, TURKEY

Lake Burdur is a closed-basin, alkaline, saline lake, at 847 m above sea level in south-west Anatolia, Turkey, divided between the provinces of Burdur to the south and Isparta to the north. Lake Burdur lies in an isolated closed basin entirely surrounded by the Burdur Lake basin, which exerts a very strong influence on the hydrology and sedimentology of the lake. The 1671.025 km2 surface-water drainage basin containing Lake Burdur, as defined by topographic maps, is long and narrow. The lake is situated along the west-central boundary of the basin, and is about 30 km long by 7 km wide .When the lake surface is at an elevation of 843.40 m above sea level , it covers an area of nearly 155.666 km2, with an average depth of 53.83 m and a maximum depth of 60.92 m . The main resources that feed the lake are rainfalls, rivers and underground water resources. Among the important water resources that feed the lake are Bozçay, Suludere, Keçiborlu River and Asar River. The main reason for the decrease in the water level of Burdur Lake is the dams and ponds constructed on the rivers that feed the lake since 1970. The pH values for Lake Burdur ranged from a minimum of 9.1 to a maximum of 9.13 with the mean of 9.116 respectively. The electrical conductivity (EC) values in Lake Burdur ranged from 32160 to 33770 μS/cm, with an average 32863.3 μS/cm , in the groundwater ranged from 607 to 6200 μS/cm, with an average of 2786.3 μS/cm. The values of Ca2+ and Mg2+ varied from 10.7 to 62 mg/l and 646 to 5880 mg/l with an average value of 32.53 and 2737.67 mg/l in lake water samples collected from various sites. The values of Na+ and K+ varied from 3630 to 7530 mg/l and 95.3 to 636 mg/l with an average value of 6301.7 and 285.1 mg/l in lake water samples. The values of HCO-3 and Cl-and ranged from 952 to 1330 mg/l and 904 to 6960 mg/l with an average value of 1177.5 and 5647.3 mg/l .The values of SO42− reported for lake water samples varied between 1800-14300 mg/l with an average value of 11450 mg/l. Similarly, the value of CO-3 varied from 390 to 636 mg/l with an average value of 561 mg/l .