Unleashing the Untapped Potential: Groundwater Exploration in a Watershed Environment of North-East India Using MCDA-AHP Techniques

Abstract

The contemporary era is marked by the faster exploitation of groundwater resources due to the combined effects of burgeoning population and rapid industrialisation. This study tries to delineate the groundwater potential zones (GWPZs) in a fragile and agriculturally dominant watershed of North-East India using the GIS-based multi-criteria decision analysis (MCDA) approach and the Analytical Hierarchy Process (AHP) technique. The study has undertaken 10 influencing factors: geomorphology, geology, land use/land cover (LU/LC), drainage density, rainfall, soil texture, slope, lineament density, topographic wetness index (TWI) and normalised difference water index (NDWI). Suitable weights for the parameters are assigned according to their relative importance and association with groundwater storage based on a pairwise comparison matrix (PCM). Four GWPZs with their respective coverages namely poor (3.39%), moderate (24.98%), good (33.36%) and excellent (38.27%) categories are found. The central and southern parts of the study area covering a portion of Udalguri, Sonitpur and Darrang districts of Assam have porous geological settings and floodplains, indicating high groundwater potentiality. In contrast, the northern part with hard and rugged terrain lacks groundwater storage. Incorporating the socio-economic aspect, particularly the number of villages with or without access to suitable groundwater, significantly enhances the study's utility. The outcome is cross-verified with the well data obtained from the Central Groundwater Board (CGWB) and field data which is validated using the receiver operating characteristics (ROC) curve resulting in an accuracy of 72.9%. Hence, this inquiry has implications for both regional and global significance and will assist stakeholders and authorities in creating a roadmap for sustainable and effective water use.