Mapping and validation of groundwater potential zone from alluvial plain: a case study of Muzaffarpur, Bihar, India

The present research integrates remote sensing (RS), Geographic Information Systems (GIS), and Multi-Criteria Decision Making (MCDM) techniques to identify groundwater potential zones (GWPZs) in Muzaffarpur. Various data sets and study areas were considered to contribute to groundwater availability. The groundwater potential was evaluated, and later, the GWPZ map was validated. It was further categorized into various potential zones from 2005 to 2020. High potential areas, located in gently sloping terrains conducive to high infiltration and percolation, maintained coverage of about 50% of the watershed. Poor potential zones, which represent a small fraction of the area with limited groundwater capacity, showed a consistently low proportion over the years. It highlights the impact of geological and geomorphological factors, particularly the Charnockite Gneiss Complex and sedimentary rocks of the Ganges Basin, on groundwater potential. Soil types, ranging from fine to coarse loamy, play a significant role in groundwater recharge. Rainfall and slope are crucial factors that influence groundwater potential. Higher rainfall and flatter slopes enhance groundwater recharge, emphasizing the importance of variables in assessment. ROC analysis revealed mixed validation results, with zones showing high potential, while others remained poor. It underscores the need for effective water conservation practices to improve groundwater availability.