A hydrochemical and remote sensing approach to decrypt the groundwater salinization in the coastal district of Sabarmati basin, Gujarat

Abstract

Coastal cities worldwide are witnessing large-scale salinity both inland as well as coastal salinity, especially in semi-arid regions. The economic aspiration and changes in land use associated with the excavation of unsustainable groundwater withdrawal is leading to saline up-coning as well as seawater intrusion in the coastal aquifers. The present study has been conducted in Anand district of Gujarat, India, to evaluate the genesis of salinity in the coastal aquifers. In the current study, both conservative elements and stable isotopes are used to explain the controlling factors of groundwater salinization and its hydrogeochemical processes. LISS-IV (Linear Imaging Self-scanning) was used to map land use land cover to understand the impact of land use practices on groundwater conditions and salinity mapping. From 2006 to 2018, the surveying and mapping of saline soil showed an increasing trend, which indicates high salinity in groundwater regime and soil characteristic. The chemical constituents coming from reverse ion exchange mineral dissolution as well as anthropogenic sources of saline water are demarcated using saturation index and ionic ratio. The origin of water salinity is described using δ18O and δD, the relationship regression line below LMWL suggests significant evaporation of recharging water before infiltration.