IWRA Proceedings

AbstractABSTRACT The Ground Water Department of Andhra Pradesh estimates the Stage of Groundwater Development (SGD) as the groundwater utilization (Draft) divided by the groundwater potential (Availability). According to this, the state of Andhra Pradesh is currently facing a general overuse of the groundwater resource, mainly due to agriculture irrigation demand. As a measure to fight against groundwater overexploitation, the Central Ground Water Board of India has promoted for the past 10 years the construction of percolation tanks or the conversion of traditional water harvesting structures for irrigation into percolation tanks. Consequently, the number of artificial structures for storing runoff water has exponentially increased during the last decade. Despite the many artificial recharge programmes implemented in various Indian states, the impact of these measures has been little scientifically studied with the notable exceptions of Sukhija et al. (1997) and more recently Sharda et al. (2006), who estimate recharge efficiency of artificial tanks between 35% and 50% in hard rock aquifers. Some studies at a local level suggest that artificial recharge may be negligible compared to the groundwater recharge whilst the amount of surface water stored in artificial percolation tanks has large consequences on water inflows to the main surface water reservoirs downstream. For instance, in the Musi basin, gross storage capacity of Osman Sagar and Himayath Sagar reservoirs for Hyderabad city water supply has declined by 12% and 20% during the last three decades due to upstream watershed development. In the framework of the SUSTWATER Project (EuropeAid), the Gajwel watershed (80 km2) categorized as Critical (90