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Amid apprehensions over deposition of sediments in Vembanad Lake and calls for increasing the water storage capacity of the waterbody, experts at the International Research and Training Centre for Below Sea Level Farming (IRTCBSF), Kuttanad, under the State government have warned that de-silting the waterbody by bottom dredging for flood management will disturb the blue carbon ecosystem in the region.
Coastal ecosystems, known as “blue carbon,” excel at capturing atmospheric carbon. Their lush vegetation not only absorbs the carbon dioxide but also channels it down to the soil, where it gets buried for centuries. It is one of several climate change mitigation measures considered globally. Researchers say that wetlands like Vembanad, a Ramsar site and the second-largest wetland system in India, are major blue carbon ecosystems.
“Apprehensions have been raised that the Vembanad Lake will turn into a swamp if the sedimentation process is allowed to continue. To improve the storage capacity, heavy dredging of bottom sediments from the lake has been suggested. While implementing projects for increasing lake capacity, instead of carrying out bottom dredging that disturbs carbon stores, we need to devise programmes to ensure effective carbon storage that help containment of organic carbon,” says K. G. Padmakumar, Director, IRTCBSF.
A study published in 2023 by the Centre for Aquatic Resource Management and Conservation, Kerala University of Fisheries and Ocean Studies, revealed that the water retention capacity of the waterbody has been reduced by 85.3%. From 2,617.5 million cubic metres in 1990, the capacity reduced to 384.66 million cubic metres in 2020.
Stating that blue carbon ecosystems play a key role in determining the progression, mitigation and outcomes of climate change, experts call for a return to the traditional process of gathering silt from the upper strata of the lake for rejuvenating it.
“Blue carbon habitats are considered bunkers of biodiversity and fisheries production. Alongside their essential role as carbon sinks, these ecosystems are fundamental to the livelihoods and food security of many people. In this context, the massive and indiscriminate desilting suggested for rejuvenating Vembanad Lake should be appropriately modified in tune with the traditional process of gathering silt from the upper strata and the same utilised for the formation of mangrove bio shields on the mud dykes along the shorelines. It will increase the lake’s storage capacity,” says Mr. Padmakumar.
The IRTCBSF suggests bringing governments, research institutions and non-governmental organisations together to advance the management approaches and pioneering a mechanism for blue carbon credits. Ends...
