Investigation on Submarine Groundwater Discharge at Kozhikkode Coastal Aquifer, SW Western Ghats

The direct discharge of groundwater to sea through aquifer medium (Submarine Groundwater Discharge), has been recognized as a small but significant component of hydrological cycle as it often transfers considerable amount of nutrients and pollutants to the sea. Understanding on Submarine Groundwater Discharge (SGD) allows us to estimate optimum exploitation levels of coastal fresh groundwater and to locate feasible waste disposal sites in coastal zones. SGD is temporally and spatially variable as interactions between multiple forcing mechanisms vary at any given location and time. Thus, site-specific investigation is necessary to comprehensively evaluate the timing, magnitude, and importance of SGD in any region. The potential of thermal remote sensing (IR imagery) was resorted to target the possible SGD zones in the initial phase. Subsequently, hydrogeological, hydrochemical and resistivity surveys have provided adequate field evidences to delineate the direct discharge areas. Though sandy horizons form the main aquifer material, laterite and weathered/fractured rock were also found to be functioning as aquifer zones. Based on different field investigation techniques, a total of three areas such as, Gotheeswaram, Kappad and Koyilandi were identified as potential groundwater discharge zones in the Kozhikkode coastal aquifer.