Decisive significance of lineaments on groundwater occurrence in the Khapri watershed of Deccan Volcanic Province (DVP), district Dangs, Western India

This study investigates the influence of geological lineaments on groundwater occurrence in the Khapri watershed, Dangs district, Gujarat, where rugged terrain and less transmissible basaltic rocks limit infiltration despite high rainfall (2000 mm). Lineaments were mapped using IRS LISS-III satellite data and eight hill-shades generated at various azimuth angles (45°, 90°, 135°, 180°, 225°, 270°, 315°, and 360°) from Carto-Digital Elevation Model (DEM) in GIS environment to ensure maximum extraction. These lineaments, validated through Google Earth and ground-truthing, were categorized into positive (ridges, plateaus, dykes) and negative (joints, fractures, straight stream segments) based on their contribution to water infiltration. The comprehensive lineament map revealed dominant NNE-SSW and ENE-WSW orientations. Positive lineaments largely induce runoff, while negative lineaments support water infiltration. The study indicates a moderate correlation between lineament densities and the groundwater regime. Regions with high negative lineament density exhibit lower groundwater fluctuation, indicating better groundwater occurrences, while areas with high positive lineament density show greater fluctuation, indicating lesser groundwater occurrence. Linear regression analysis indicates that 48% and 50% of the variation in groundwater fluctuation is explained by positive and negative lineament density, respectively. This analysis emphasizes the importance of identifying and mapping negative lineaments for targeting groundwater resources in hard rock terrains.