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Groundwater movement and its properties are unique with reference to its place of occurrence. Karnataka State can be considered as having three major hydrogeological provinces Viz. Archaean crystalline province, Metamorphosed sedimentary province, and Deccan Trap province. Ground water occurs in these provinces under unconfined to semi-confined conditions and under confined conditions in depth. The rock units in these provinces do not have the primary porosity, therefore, the occurrence and movement of ground water is through secondary porosity developed from the weathering and structural deformity undergone by the rocks. Hence, a study of ground water occurrence in two distinct geological setups i.e. Deccan Trap terrain of Eocene to Upper Cretaceous age (Afzalpur taluk) andPeninsular Gneissic terrain of pre-Cambrian age (Hassan district) has been attempted. Afzalpur taluk, Gulbarga district is underlain by basalts and followed downwards by Shale and Limestone. Ground water accounts 88% of the net area under irrigation and is the only dependable source for domestic, agriculture and industrial sectors. As per the Dynamic Ground Water Resources Estimation (2009), Stage of ground water development in the taluk is 94% and is categorized as ‘Critical’. Under Ground Water Exploration programme during the year 2010-2013, 21 bore wells were constructed up to a depth of 300 meters in the taluk at different locations.Hassan district is underlain by peninsular gneiss, granites and schists. Ground water accounts 27% of the net area under irrigation. As per the Dynamic Ground Water Resources Estimation (2009), Stage of ground water development of the district is 46% and is categorized as ‘Safe’. Under Ground Water Exploration programme during the year 2010-2011, 18 bore wells were constructed up to a depth of 200 meters in Channarayapatna, Hassan, Alur and Belur taluks of Hassan district at different locations. Data collected during the drilling and post drilling were analysed and compared to decipher the occurrence of ground water in different geological setups. The analysis shows that the BGC forms a better aquifer as compared to the Basalts.

Nitrate concentrations in surface and groundwater bodies in India are increasing due to rapid urban development as a consequence of increasing economic-growth rates and N fertilizer applications in agriculture to meet food demands of increasing population. High nitrate concentration in drinking water poses threat to human and animal health and may cause eutrophication of aquatic systems threatening fish, biodiversity, aesthetics, and economics. In states such as Punjab, Haryana, Delhi, Maharashtra, and Andhra Pradesh with intense economic and agricultural activities, nitrate concentrations are increasing in ground and surface waters. Nitrate concentrations in river systems tend to be higher in regions of high-economic activity and population pressure compared to those of less-economic activity and population. Overexploitation of groundwaters accompanied by urban development and agricultural intensification will exacerbate nitrate pollution of groundwaters in the country. Subsidy for N fertilizers in India has resulted in increasing inputs of reactive nitrogen to the environment. Improved sewage treatment and fertilizer N management methods coupled with recent policy initiatives, such as using more organics in agriculture and mandatory coating of all urea with neem, and river cleaning missions will reduce nitrate pollution of waters. More comprehensive monitoring of nitrate in surface and groundwaters accompanied by the implementation of water policy regulations will help in combating nitrate threat to water quality.