Delineation of groundwater potential zones in a drought-prone semi-arid region of east India using GIS and analytical hierarchical process techniques

Over-extraction of groundwater has compromised its climatic resilience properties and the arid/semi-arid rural tracts are becoming increasingly vulnerable to the risks of groundwater scarcity. This study has employed a combination of Geographical Information System (GIS) and Analytical Hierarchical Process (AHP) techniques to delineate the Groundwater Potential Zones (GPZs) of the semi-arid Birbhum district in eastern India which suffers from seasonal drought during lean periods. For a reliable evaluation, a large number of thematic layers (N = 12) including geology, geomorphology, Land Use/Land Cover (LULC), fault and lineament density, drainage density, rainfall, soil type, slope, roughness, topographic wetness index, topographic position index and curvature were considered for this assessment. Multicollinearity and consistency checks were performed prior integrating the layers to avoid a non-trivial degree of accuracy in prediction output. The GPZ map was obtained with an accuracy of 80.49% with respect to the observation tube well data. Based on the obtained output, 38.24%, 24.24% and 11.14% of areas of the district classified as moderate, poor, and very poor GPZs, respectively, whereas only 26.38% of the district classified as high to very high GPZs. Cross-validation using the Receiver Operating Characteristic curve revealed a good prediction accuracy of 71.50%. Furthermore, map removal and single parameter sensitivity analysis was also performed which revealed geology, geomorphology, soil types, rainfall, LULC and lineament density as the most influential parameters for the prediction model where exclusion of any thematic layer significantly changes the prediction accuracy and area of each GPZ class. The most convincing GPZs are recorded in some parts of the Mayurakshi and Ajay river basins and certain alluvial aquifer regions. Nonetheless, the study recommends the adaptation of Managed Aquifer Recharge techniques including rainwater harvesting, alternative cropping patterns and irrigation techniques such as sprinklers, drips and micro irrigations to increase the groundwater potential of the water crisis zones.