Studies on the Physico-Chemical Parameters and Pollution Indicator Algal Flora of Main Nara Valley Drain Water Entering Manchhar Lake (Distt. Dadu) Sindh, Pakistan

Abstract

Main Nara Valley Drain (MNVD) is a distributary of Indus river which was constructed in (1932) in Sukkur barrage command area. It connects Hamal lake with Manchhar lake through regulator. Water samples of Main Nara Valley Drain entering Manchhar lake were collected at monthly intervals between January to December 2001. These samples were analyzed for temperature, Secchi disc depth, conductivity, total dissolved solids, chemical oxygen demand, total nitrogen and orthophosphate contents. The results indicated that the salinity (1.26.4 g/l), conductivity (2.35 11.34 mS/cm), total dissolved solids (8906200 mg/l), hardness (710994 mg/l) and chemical oxygen demand (60284 mg/l) values were far beyond the permissible limits of WHO standards for drinking water. Sixty one algal species belonging to Cyanophyta (23), Chlorophyta (21), Euglenophyta (16) and Rhodophyta (1) were identified. The algal genera Anabaena, Microcystis, Merismopedia, Oscillatoria, Euglena and Scenedesmus were considered as indicators of eutrophication as well as organic 'Pollution Index' species. The water quality of Main Nara Valley Drain is drastically degrading the quality of Manchhar lake along with the biotic components.