Environmental Assessment of Water Quality in Nagarjuna Sagar Reservoir, India

Abstract

The quality of water determines its usage for any intended purpose. We studied the quality of water in the Na- garjuna Sagar reservoir, one of the biggest surface water reservoirs in India with an aim to determine the suitability of the water for domestic and agricultural use. This reservoir supplies water to the irrigational needs of five districts and the drinking water supplies of nearby towns. We collected water samples once in two months between July 2008 and January 2010 from the reservoir. We measured pH and EC of the samples in the field. The concentration of calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulphate, fluoride, nitrate and uranium were analysed in the laboratory using standard procedures. The suitability of water for drinking purpose was determined by comparing the results of the analysis with the drinking water guidelines of the Bureau of Indian Standards and World Health Organisation. Even though the groundwater in this area is rich in fluoride and uranium, this does not affect the water quality of the reservoir for drinking water supply. The comparison of the water samples with the irrigational water quality assessing factors such as percent sodium, residual sodium carbonate, magnesium hazard, sodium absorption ratio and permeability index also indicated the suitability of water for agricultural use. As the water in the Nagarjuna Sagar reservoir is suitable and good for drinking and irrigational use, not much treatment needs to be carried out except for disinfection before supplying it for domestic use.