Groundwater Quality Assessment of Bhaskar Rao Kunta Watershed, Nalgonda District, Andhra Pradesh, India

Semi-arid region of Bhaskar Rao Kunta watershed was studied to evaluate hydrogeochemical characteristics of the fractured, semi-confined and water-stressed aquifers. Twenty groundwater samples were collected from deeper bore wells during pre and post monsoon seasons in June and December 2009. The samples were analysed for concentration of physico-chemical parameters (pH, EC, TDS, TH, Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^-, SO₄^2-, Cl^-, NO₃^- and F^-). The results were interpreted with Piper, Gibbs and Wilcox diagrams. For interrelationships, the parameters were measured with correlation matrix and t-test methods. Bureau of Indian Standards specifications were used and verified for suitability of groundwater quality. The type of the groundwater quality was understood from the interpreted diagrams of Piper (85% magnesium bicarbonate and 15% mixed type of samples), Gibbs (100% evaporation type samples) and Wilcox (85% high salinity and 15% moderate salinity type of samples). The highest correlation was found between EC and TDS with a correlation coefficient of 0.98 and the t-test behaviour was not significance, therefore, the geogenic and rock water interaction was negligible with respect to seasonal variation. Due to high concentration of fluoride (<1.5mg/L) and salinity (750 ≤ 2250 μS/cm), the groundwater quality was not suitable for drinking, and special drainage system and crop practices are requisite for irrigation purpose in the study area.