Hydrogeology and hydrogeochemical characterisation of groundwater of a part of Nalgonda District Andhra Pradesh India

Abstract

Groundwater always contains some amount of chemical constituents and their concentration is a function of water, rainfall, land use, formation of rocks and recharge processes. The aim of the present study is to understand the hydrogeology and hydrogeochemistry of the groundwater of a part of Nalgonda district, Andhra Pradesh, India. The major objectives of this study are to understand the hydrogeology of the area, identify the spatial and seasonal variation in major ion chemistry of groundwater, characterize the groundwater geochemistry of the aquifer system and determine the hydrogeochemical processes that control the groundwater chemistry. The major geochemical processes controlling the major ion chemistry of the groundwater are evaporation, ion exchange, silicate weathering and dissolution of minerals. Relation between groundwater level and saturation index of minerals reveals the importance of evaporation process on groundwater ionic concentration and irrigation practice in this arid region. Even though the groundwater occurs in granitic formation, geochemically many groundwater samples collected are over saturated with respect to calcite and dolomite. This work has demonstrated the significance of hydrogeochemical studies in understanding the variation in groundwater chemistry and helped in the identification of hydrogeochemical processes in this hard rock region. This will form a base line study as it is proposed to mine the uraninite present in the unconformity between the cuddapah and archean formation of this region. Identified geochemical process will serve as background information and will help to know if there are any changes in groundwater environment in future due to the proposed mining and milling activity in this area. Further, the hydrogeological and hydrochemical studies formed a basis for carrying out the numerical and hydrogeochemical modelling to understand effect proposed uranium tailings pond on groundwater environment in this area. newline newline newline