Hydrogeological and Hydrochemical Characterization of Coastal aquifers with Special reference to Submarine Groundwater Discharge in Uttara kannada, Karnataka, India

Abstract

Submarine groundwater discharges to the coastal ecosystems have been recognised as a source of dissolved chemical substances that cause chemical and ecological effects on sea waters. Groundwater, in many coastal areas, becomes contaminated or at least enriched with a variety of chemical substances and can have higher concentrations of dissolved solids than river water. As a result SGD makes a larger contribution to the flux of dissolved chemical compounds than river run-off. Therefore, the present investigation has been carried out to understand the process of submarine groundwater discharge based on hydrological, hydrogeological and hydrochemical components. Accordingly water balance components were evaluated based on hydrological and hydrogeological investigations. Hydrochemical parameters were also evaluated to understand the impact of seawater intrusion during both pre-monsoon and post-monsoon seasons of 2019. Study revealed that, there are signatures of considerable quantity of submarine groundwater discharge in parts of Honnavara, Kumta, Ankola and Karwar talukas. The influence of seawater in coastal aquifers is quite rare all along the coast of Uttara kannada district which is attributed to high groundwater recharge(15-20%) occurring in catchment areas.