Threatened groundwater resources in rural India : an example of monitoring

In the absence of available surface water in semi-arid areas, groundwater has become the main water resource for various purposes. In many places in southern India, groundwater even is the only source of drinking water in rural areas. Therefore, quality and quantity aspects of groundwater management constitute acute issues for the well-being of Indian rural populations. This study proposes to use borewells drilled by farmers for irrigation purposes in order to assess the quality and quantity of available groundwater. A very accurate map of the water table and its variations was drawn and zones of water table depletion were compared to water pumping locations. Overexploitation is quantified at the watershed scale. Quantity is associated with quality. A groundwater electrical conductivity map reveals highly mineralized groundwater near the villages, and pollution plumes downgradient of the main inhabited areas. The absence of sewage or solid waste collection and treatment facilities threatens groundwater quality by increasing its chloride content, even in such small rural villages. The overall analyses indicate increasing risk for sustainability of groundwater resources. At the regional scale, salinisation of groundwater due to irrigation practices is suspected.