Delineation of Potential Groundwater Zones using GIS-based Fuzzy AHP technique for urban expansion in the South Western fringe of Guwahati City, India

Abstract

Due to unprecedented urban growth many localities within the heart of Guwahati city witness groundwater scarcity, mainly during the dry seasons. This study aims to identify potential groundwater zones in the southwestern fringe of the city where the Guwahati Metropolitan Development Authority (GMDA) has adopted plans for future expansion.. Rani and Chayani Barduar are two administrative blocks adjacent to the city possessing a vast tract of unsettled agricultural land ideal for future township development. Multi-criteria decision-making technique using a Fuzzy Analytical Hierarchy Process (FAHP) in Remote Sensing and Geographic Information System (GIS) environment is used to produce the groundwater potential map. A total of eight thematic layers important for groundwater recharge: lithology, geomorphology, slope, rainfall, lineament density, soil, drainage density, and Land Use Land Cover are prepared using satellite data, fieldwork, and other suitable techniques and used as input. The study area is classified into five groundwater potential zones – very high (42.52%), high (28.67%), moderate (17.23%), poor (10.21%), and very poor (1.37%). Validation of the result using a yield map derived from the exploratory wells of Central Ground Water Board (CGWB) shows strong agreement with the prediction accuracy (AUC = 73.36%). Field-derived water level data also show a high negative correlation (R2 = 0.71) with yield data indicating high specific yield in wells with shallow water levels. The study results will help planners and policymakers with future urban development strategies and sustainable groundwater management practices.