Hydrological assessment of groundwater potential zones of Cauvery River Basin, India: a geospatial approach

Groundwater is one of the prime sources of freshwater in tropical and sub-tropical regions. The unsustainable abstraction of groundwater and marked changes in the climate due to natural and anthropogenic processes, over the years, have imposed immense pressure on the pristine freshwater sources. Lack of adequate information on the spatial distribution of groundwater resources and its availability to human consumption is one of the challenges before the water managers of many fast-developing economies of the world. This warrants the need for a low-cost, easily applicable and reliable technology to assess the groundwater potential of river basins-the most fundamental unit for spatial planning. Here, we report a study carried out for delineation of groundwater potential zones in the Cauvery river basin (Basin area 82,283 km(2)) in Peninsular India using weighted overlay method, employing a total of 12 thematic layers. Weights assigned to each class in the thematic maps are based on their characteristics and water potential capacity following the analytical hierarchical process techniques. The resultant groundwater potential values were then classified into five categories such as excellent, good, moderate, low and poor for further analysis. An overall evaluation of the results reveals that about 65% of the basin area falls under moderate groundwater potential zones and 19% under excellent to good categories. The remaining areas fall under low and poor groundwater potential zones. An inter-comparison of the observations of the present study with that of the well data and ground truth verification reveals that the method adopted herein for the delineation of groundwater potential zones is about 85% accurate and hence the people concerned can go for further high-resolution investigations including direct test methods for groundwater development planning and its sustainable utilization.