Advances of Submarine Groundwater Discharge in the Coastal Aquifers of India: A Review

Abstract

Groundwater is a crucial freshwater source for coastal communities. However, population growth, urbanization, industrial activities, and the discharge of polluted sewage water have led to the contamination of coastal groundwater with nutrients, metals, and organic compounds. This contaminated groundwater and terrestrial groundwater discharges into the ocean through a process known as Submarine Groundwater Discharge (SGD). This study aims to review (i) the driving forces behind SGD across coastal barriers, (ii) methods for identifying and quantifying SGD sites, and (iii) the status of SGD in Indian coastal aquifers and groundwater resource availability. The study indicates that groundwater discharge is higher on the east coast of India than on the west coast. Data on groundwater resources in India’s coastal states show an increase in annual groundwater extractions for irrigation, industry, and domestic use, with a decreasing trend in net groundwater availability for future use between 2011, 2013, and 2017. Despite this, there is limited evidence on the quantity of SGD flux along the Indian coastline. However, preliminary studies by the Mission SGD project have made some progress in understanding this phenomenon. This research aims to improve the estimation of water resources in India and highlight the volume of SGD entering the ocean. A comprehensive understanding of hydrogeological settings, computational methods, coastal aquifer geometries, and other factors is essential for accurately estimating SGD along the Indian coastline. © 2025 by the authors Licensee: Technoscience Publications.