Hydrogeophysical characterization and numerical contaminant transport modelling for groundwater ecosystem restoration in an industrial watershed, South India

Abstract

Industrial groundwater contamination threatens groundwater ecosystems, particularly in hard‐rock aquifers of rapidly developing industrial regions. This study integrates hydrogeophysical investigations with numerical groundwater flow and contaminant transport modelling to characterize contaminant migration in the industrial watershed, Hyderabad, India. Electrical resistivity tomography surveys at 44 locations and lithological data from 32 boreholes were used to develop a three‐dimensional hydrogeological framework. Low‐resistivity values (<10 Ω m) identified highly saturated and contaminated zones, whereas weathered and fractured granitic formations (<10–150 Ω m) acted as preferential contaminant pathways, and fresh granitic bedrock displayed resistivity values exceeding 250 Ω m. The interpreted hydrostratigraphy was incorporated into a MODFLOW–MT3DMS model to simulate groundwater flow and contaminant transport. Results showed groundwater velocities of 0.9–1.2 m day ⁻¹ , with contaminant migration concentrated within shallow weathered horizons. Simulated total dissolved solids concentrations exceeded 15,000 mg L ⁻¹ near source areas and migrated in down gradient towards lake and connected drainage systems. Integrating geophysical observations with numerical modelling increased conceptual understanding and improved delineation of contaminant pathways. The study demonstrates that hydrogeophysically constrained groundwater models are valuable tools for groundwater ecosystem restoration, remediation planning and sustainable management of industrially contaminated aquifers.