IDENTIFICATION OF GROUNDWATER POTENTIAL ZONES IN BHARATHAPUZHA RIVER BASIN USING GIS BASED AHP TECHNIQUE

Abstract

Identification of GWPZs is essential for sustainable groundwater management in the BRB. This study aim to delineate GWPZs in the BRB by integrating GIS and AHP. Eight thematic layers namely geomorphology, geology, land use/land cover, soil, slope, drainage density, lineament density and rainfall were selected based on their influence on groundwater recharge and occurrence. A weighted overlay analysis was performed in the GIS environment to generate the groundwater potential index map and it was reclassified into five categories; very poor, poor, moderate, high and very high groundwater potential zones. Validation was carried out by overlaying observation well locations. Furthermore, to evaluate the influence of rainfall variability, additional analyses were conducted under extreme rainfall conditions minimum non-zero annual rainfall and maximum annual rainfall while keeping other thematic layers constant. The study highlights the spatial distribution of groundwater potential and emphasizes the significant role of rainfall in groundwater recharge dynamics in BRB.