GROUNDWATER POTENTIAL ZONE MAPPING OF EAST CHAMPARAN DISTRICT, BIHAR USING GEOSPATIAL AND AHP TECHNIQUE

Abstract

The groundwater is an important source of water for many sectors and mainly agriculture and domestic sector relies on groundwater in India. However, groundwater potential zone identification is critical under the complex hydrogeological and climatic conditions especially in East Champaran District of Bihar. Therefore, this study carried out a comprehensive analysis of Groundwater Potential Zones (GWPZs) in the East Champaran district of Bihar utilizing Remote Sensing (RS), Geographic Information Systems (GIS), and the Analytical Hierarchy Process (AHP). Data was collectedfrom various sources such as CGWB, IMD, USGS Earth Explorer and FAO. The various thematic layers of key variables were created using the GIS, which influence on groundwater potential zones. These includes elevation, slope, drainage density, land use/land cover (LULC), soil type, rainfall, curvature, geomorphology, lithology, and aspect. Groundwater potential zones are assessed using AHP techniques by providing scale ranging from 1 to 9 for each of the identified variables, which is governed by groundwater potential zones, where a score of 1 indicates equal importance and 9 signifies extreme importance of one factor over another. The weightage and ranks are assigned to each of the factors, which influence on groundwater potential zones using AHP technique in case of East Champaran District of Bihar. The groundwater potential zones in the district were categorized into low, medium and high potential zones. The results indicate that 81.28% of the district is classified as medium groundwater potential, with varying groundwater levels suggesting a dynamic equilibrium between recharge and extraction processes. Low groundwater potential zones, which cover 17.07% of the district, are marked by deeper groundwater levels indicating ecological stress and the need for restorative measures. Although, high-groundwater potential zones comprise only 1.64% of the district, they exhibit shallow groundwater levels reflecting thriving ecosystems supported by rich aquifers, indicating potential for sustainable development. By employing AHP, the study enabled a quantitative analysis of the thematic layers, facilitating a robust, systematic, and weighted evaluation. The resulting maps, which cover 671.37 km² for low potential, 3195.34 km² for moderate potential, and 64 km² for high potential zones, provide critical insights into the district's hydro-geological diversity.