Groundwater quality suitable zones identification: application of GIS, Chittoor area, Andhra Pradesh, India

Due to uneven spatial and temporal distribution of rainfall and lack of sufficient water management technologies, the development activities of the society are totally depending on groundwater resources. In addition to the prevailing drought-prone conditions, the improperly treated and unplanned release of effluents of industry, municipal and domestic into the nearby streams and ponds and the majority usage of groundwater for irrigation are increasing the ionic concentration of the groundwater and making it more saline. The analytical results of the collected groundwater samples show that the groundwater is alkaline, and sodium and bicarbonate are the dominant cation and anion, respectively. Gibbs variation diagram shows that the control of the chemistry of groundwater in the study area is the weathering of granitic gneisses and also the leaching of evaporated and crystallized ions from the topsoil of the irrigated areas and improperly treated industrial effluent ponds. GIS, a potential tool for facilitating the generation and use of thematic information, has been applied and analyzed for identification of groundwater quality suitable zones for domestic and irrigation purposes. 30.06% of the area is with suitable, 67.45% of the area is with moderately suitable and 2.45% of the area is with unsuitable quality of groundwater for domestic purpose. 46% of the area is with suitable, 53.36% of the area is with moderately suitable and 0.64% of the area is with unsuitable quality of groundwater for irrigation purpose.