Construction of large dams on the Brahmaputra and its tributaries, being opposed by many quarters, is also posing a serious threat to river Dolphins which are on the verge of extinction.

Noted dolphin expert Dr Abdul Wakid said the Brahmaputra river system in Assam is considered as one of the last refuges of the species unimpeded by dams in its sea-bound flow compared to the Ganga.

“But the situation will change once the dams come up on the river’s tributaries and forerunners as proposed in Arunachal Pradesh and Meghalaya,” Wakid, also the head of Aaranyak’s Gangetic Dolphin Research and Conservation Programme, said.

In a recent survey conducted in the entire Brahmaputra river system, a team, led by Wakid, recorded the existence of 264 dolphins. Of them, 212 dolphins are in the Brahmaputra mainstream, 29 dolphins in Kulsi river and 23 in Subansiri river.

Among the 168 dams proposed to be built in the Northeast, the Lower Siang, Dibang, Lower Demwe, Lower Subansiri and Kulsi dams have been identified as the most threatening dams for the survival of Brahmaputra dolphins, Wakid pointed out.

Construction of dams causes major changes in flow regime, sediment load and water quality of running water besides degrading the dynamic attributes of downstream water and reduce the flow of sediments essential to the formation of stream channel islands and bars, Wakid said.

“Therefore, we strongly recommend that a river basin planning approach, including cumulative impact assessment studies in advance, need to be developed for the better future of the dolphins as well as Brahmaputra riverine ecosystem,” Wakid said