GUWAHATI, Aug 7 – NGOs and wildlife activists have urged the State Government to enforce immediately the National Green Tribunal (NTG) verdict for banning all in-stream sand mining in the Kulsi river for ensuring long-term survival of the highly-endangered Gangetic dolphin population.
The stretch of the Kulsi near Kukurmara area in Kamrup district shelters a unique residential population of the river dolphin, locally called ‘Xihu’ – the national aquatic animal of India protected under Schedule-I of the Wildlife Act 1972.
The NGT on Monday ordered a nationwide stay on sand mining on river beds without the Environment Ministry’s clearance. Earlier also, the court noted that sand mining on either side of the rivers, upstream and in-stream, was “one of the causes for environmental degradation and also a threat to biodiversity.”
“River dolphins generally do not prefer small area habitat, but a 20-km stretch of the Kulsi happens to be an exception. The stretch of the river near the township of Kukurmara is blessed with a unique topography of having connected with four adjoining beels (wetlands), making the river very rich in food fishes. But rampant in-stream mining has been a big threat to the Kulsi dolphin,” conservation biologist Dr Sujit Bairagi says.
Originating in Meghalaya, Kulsi is a southern tributary of the Brahmaputra. In Assam, the river joins a rivulet flowing out from the ancient tectonic lake Chandubi, and is known as Kulsi from that point onwards.
These wetlands also serve as the breeding ground for fishes and provide regular supply of food fishes which is the key to the flourishing residential river dolphin population.
“During 1992 over 30 dolphins were there in the river which had come down to only 11 in 2012. This was mainly because of the degradation of the river ecology due to rampant in-stream sand mining which had blocked all the connections of river with the adjoining wetlands, besides affecting the overall ecology of the river,” Dr Bairagi who has submitted a memorandum to Forest Minister Rockybul Hussain for banning sand mining, says.
During the sand extraction process the fine sand particles are washed away by the water current and deposited in the downstream areas, which makes the area shallow and silted, restricting the local migration of the dolphin population forcing them to inbreed.
Dr Bairagi says that the primary productivity of the river had drastically gone down due to increased turbidity which is affecting plankton growth, and the fish population was vanishing from the river.
