Kolkata, Powerful cyclones can affect the quality of groundwater even 100 metres below the surface in deep coastal aquifers, posing a challenge to drinking water security, according to a recent study by IIT Kharagpur researchers.
The findings of the study, published recently in the journal ‘Scientific Reports’, examined the impact of extreme climatic events on groundwater systems in Sundarbans, part of the Ganga-Brahmaputra-Meghna delta and one of the world’s most climate-vulnerable coastal regions. The study found that cyclones and atmospheric depressions can rapidly alter groundwater levels and hydraulic gradients at different depths, disturbing the balance between freshwater and seawater and facilitating the mixing of the two. Researchers studied 11 extreme climatic events between May 2017 and May 2020, including seven atmospheric depressions and four tropical cyclones Titli, Fani, Bulbul and Amphan, the study said.
“Importantly, such changes were detected even in aquifers located more than 100 metres below the ground,” the study said. Analysis of stable isotopes provided additional evidence of water movement and mixing that may not be evident from groundwater-level measurements alone, the study said. The implications of the study extend beyond the Sundarbans, with tropical deltas and coastal regions across South and Southeast Asia and other parts of the world facing growing pressure from population growth, groundwater dependence, sea-level rise and extreme weather events, it said.
The research, titled ‘Groundwater vulnerability to Amphan and other recent cyclones in a tropical mega-delta’, was conducted by IIT Kharagpur professors Abhijeet Mukherjee and Aditya Bandopadhyay, SRM University scientist Kousik Das and IIT Kharagpur research scholar Prakrity Majumder, the institute said in a statement on Tuesday.
