Trophic assessment of a semi-drainage Himalayan lake

Abstract

The present study was carried to assess the water chemistry of Lake Ahansar, a semi-drainage lake situated in the district Ganderbal of Kashmir valley. Water samples from five different locations viz., inlet, outlet, littoral zones and centre were collected for a period of 9 months covering three different seasons viz., winter, spring and summer. The season wise mean values recorded for various physico-chemical parameters were: air temperature (17.4±3.46 oC), water temperature (17.42±0.19 oC), depth (2.37±0.49m), transparency (1.5±0.1m), dissolved oxygen (9.38±0.32mg/l), pH (8.0±0.08), free carbon dioxide (9.9±0.6mg/l), chloride (13.0±0.32mg/l), total alkalinity (231.1±2.1mg/l), total hardness (317.0±1.9mg/l), calcium hardness (71.6±1.7mg/l), magnesium hardness (57.9±0.8mg/l), ammonical nitrogen (96.8±1.2µg/l), nitrate nitrogen (485.5±2.6µg/l), total phosphorous (231.0±1.1µg/l) and orthophosphate (29.8±0.6µg/l).Overall, it was established that water quality of the lake has deteriorated, when compared with earlier records.