Study recommends measures to revive Vembanad

The study says that improving the filtration efficiency of Kuttanad polders is necessary to slow down the rate of sedimentation of the Vembanad lake.

The Centre for Aquatic Resource Management and Conservation, Kerala University of Fisheries and Ocean Studies, has recommended, among other measures, increasing the water holding capacity of the Vembanad wetland system by increasing the base floor depth to create an additional capacity of 432.36 million cubic metres, which will take care of the problems of inundation and flashfloods during moderate to heavy rain.

However, dredging and removal of such a large volume (399 million cubic metres of bottom sediments) should be taken up with proper precaution and after an environmental impact assessment, it says.

The study also says that improving the filtration efficiency of Kuttanad polders is necessary to slow down the rate of sedimentation of the lake. Among solutions suggested to mitigate inundation of the low-lying areas adjoining AC Canal is interconnecting the broken links at Mancombu and Nedumudy-Ponga segments.

While microplastics (3,005 tonne dry weight in the upper one-metre depth of the lake) is expected to be removed during the dredging operations to deepen the lake, plastic should be sorted out of the dredged material with the help of local government bodies and SHGs before being used to broaden the banks of the estuaries and rivers.

The study also points to environmental degradation and overexploitation as resulting in depletion in resources such as fin fish and black clams. Floating aquatic weeds and jelly fish menace have added to the problems. The surveillance and compliance mechanisms against overexploitation of resources are not imposed strictly. A fully regulated fishery regime with a three-tier management is recommended.