Spatial assessment of groundwater potential zones using remote sensing, GIS and analytical hierarchy process: A case study of Siliguri subdivision, West Bengal

One of the most significant natural resources, groundwater is essential to providing a long-term, reliable and sustainable global water supply. Therefore, delineating Groundwater potential zones (GWPZs) is crucial in effectively managing groundwater reserves. The present study attempts to delineate GWPZs in the Siliguri subdivision of West Bengal using integrated Remote Sensing (RS), Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) in the light of a considerable shift in the patterns of groundwater usage, especially considering the ongoing rise in demand for groundwater owing to a variety of causes. Raster layers of fourteen causative factors Viz. geomorphology, lithology, lineament density, soil texture, elevation, slope, land use and land cover (LULC), river density, rainfall, pre-monsoon groundwater depth, post-monsoon groundwater depth, groundwater fluctuation, topographic wetness index (TWI) and topographic roughness index (TRI) are used to delineate GWPZs using AHP in GIS software. The final GWPZs map was categorised into five classes: very high (25.67%), High (31.77%), moderate (20.73%), low (17.67%) and very low (4.15%). The results are further validated by evaluating the receiver operating characteristic (ROC) curve with the groundwater level depth from 39 dug wells. The ROC curve shows that the AUC value is 0.818, representing a prediction accuracy of 81.80%. The comprehensive map of GWPZs will enhance managing natural assets to guarantee the continued preservation of water resources and the development of agriculture. The method utilised in this research may be used in other natural contexts with a comparable environment.