Geochemistry of Some Thermal and Cold Waters of Godavari Valley

Results of chemical analyses of fifteen thermal and cold waters of Godavari valley are reported. Agnigundala (Bhadrachalam) thermal water is of Na-Cl type and the rest are of Na-Ca-HCO₃-SO₄ type. It is likely that the Agnigundala geothermal system is associated with Archaean gneisses and is characterised with a reservoir temperature around 170°C. Other warm waters of the valley show low concentrations of dissolved solids and are similar to those which are associated with sedimentary rocks. It appears that the groundwater after movement to appropriate shallow depth, got heated up to moderate temperature (around 80-90°C). Thereby the basic chemical character of the water has not changed much due to movement, both downward and upward, through the same type of rocks.