Morphotectonic Control on Fluvial Evolution and Groundwater Dynamics in the Ithikkara River Basin, Southern India

This study integrates fluvial geomorphological analysis, morphometric indices, groundwater fluctuation data, hydrochemical signatures, and offshore sediment records to unravel the neotectonic evolution of the basin and its implications for groundwater dynamics. Quantitative assessments using indices such as bifurcation ratio (Rb), stream length-gradient (SL), hypsometric integral (HI), asymmetry factor (AF), and chi index (χ) highlight zones of uplift, tilting, and drainage realignment. GLA index analysis reveals significant deviations between predicted and observed river gradients, with knickpoints, channel deflections, and stream piracy zones serving as geomorphic markers of tectonic disequilibrium. Fault-aligned groundwater recharge zones show enhanced infiltration, particularly in northern and central sub-basins, while southern segments remain recharge-deficient.