Application of numerical modeling for groundwater flow and contaminant transport analysis in the basaltic terrain, Bagalkot, India

A three-dimensional steady-state finite difference groundwater flow model is used to quantify the groundwater fluxes and analyze the subsurface hydrodynamics in the basaltic terrain by giving particular emphasis to the well field that supplies domestic, agricultural, and industrial needs. The alluvial aquifer of the Ghatprabha River comprises shallow tertiary sediment deposits underlain by peninsular gneissic complex of Archean age, located in the central–eastern part of the Karnataka in southern India. Integrated hydrochemical, geophysical, and hydrogeological investigations have been helped in the conceptualization of groundwater flow model. Hydrochemical study has revealed that groundwater chemistry mainly controlled by silicate weathering in the study area. Higher concentration of TDS and NO₃-N are observed, due to domestic, agriculture, and local anthropogenic activities are directed into the groundwater, which would have increased the concentration of the ions in the water. Groundwater flow model is calibrated using head observations from 23 wells. The calibrated model is used to forecast groundwater flow pattern, and anthropogenic contamination migration under different scenarios. The result indicates that the groundwater flows regionally towards the south of catchment area and the migration of contamination would be reached in the nearby well field in less than 10 years time. The findings of these studies are of strong relevance to addressing the groundwater pollution due to indiscriminate disposal practices of hazardous waste in areas located within the phreatic aquifer. This study has laid the foundation for developing detailed predictive groundwater model, which can be readily used for groundwater management practices.