Application of AHP for Groundwater Potential Zones Mapping in Plateau Fringe Terrain: Study from Western Province of West Bengal

The water-stressed Joyponda river basin is situated on the hard rock terrain of Chotanagpur Granite Gneiss Complex of Archean age and older alluvium of Quaternary. An assessment is carried out to delineate the groundwater prospect zones for this densely populated river basin taking into account eleven hydro-geological factors, namely, geology, lineament, geomorphology, slope, curvature, drainage, rainfall, soil, infiltration number, topographic wetness index and land use land cover. To prepare the thematic layers of all these parameters, different maps, satellite images and data are collected from various national and international organizations and analysed in different Remote Sensing (RS) and Geographical Information System (GIS) softwares. The Analytical Hierarchy Process (AHP) model is considered in this study to assign weight for all factors depending upon their influencing capacities in the development of groundwater. The map of groundwater prospect zones is prepared integrating all the factors in GIS software. The applied model is also validated computing overall accuracy assessment and Kappa co-efficient. The study confirms that an area of 37.49% of the Joyponda river basin bears good to very good groundwater potentiality. Around 10.97% of the basin is delineated as very poor groundwater prospect zones. A significant proportion of basin area of 28.93% is moderately potential for groundwater. The result of accuracy assessment of the study ensures the 85% validity of the model. Moreover, the Kappa co-efficient is calculated as 0.81 and describes an almost perfect agreement between simulated model and reference points.