Detection of groundwater potential zones using analytical hierarchical process (AHP) for a tropical river basin in the Western Ghats of India

This paper delineates the groundwater potential zones (GWPZ) within the Tadri River Basin in the Western Ghats of India, using analytical hierarchical process (AHP) and geoinformatics-based techniques. Eight discrete parameters (slope, rainfall, drainage density, lineament density, lithological units, geomorphological units, soil types and land use, and land cover classes) were selected and weighted according to their influence on groundwater availability and combined in a hierarchical manner to obtain the resulting GWPZ map. This was classified into five classes (very good, good, moderate, low and very low) depending upon the relative groundwater availability within each. Excellent GWPZ were present in the lower part of the Tadri Basin and along the Western Ghats’ foothills beside the coast while the pediment-pediplain complex had less viability. The GWPZ map was validated using the area’s average groundwater depth and well density, via the receiver operating characteristic (ROC) curve and the area under curve (AUC), which elicited an accuracy of 79% and 82.1%, respectively. Sensitivity analysis revealed that the basin’s lithology, land use/land cover, drainage density and lineament density had the most impact in GWPZ delineation.