Chinese mega dam on Brahmaputra sparks disaster fears for Assam & Arunachal: Expert

Guwahati, Dec 31: The proposed Chinese mega dam to generate 60,000 MW of power on the Yarlung Tsangpo canyon of river Brahmaputra in Eastern Tibet can have disastrous consequences in Assam and Arunachal Pradesh as it is located at a dizzy height of 2 km above the Assam plains and in a highly seismic zone with pronounced geological instability.

For sake of risk assessment with related disaster issues as the lower riparian nation, the Government of India should request China for a comprehensive dam break analysis involving both India and Bangladesh, said internationally acclaimed river expert and former professor of the Indian Institute of Technology Roorkee Prof Nayan Sharma.

Talking to The Assam Tribune on the possible consequences of the proposed dam, Prof Sharma said that presently India does not have a water sharing treaty with China. However, as per international practice followed in other transboundary rivers, it is very much in order for India to demand a comprehensive dam break analysis to ensure safety of lives and property of the citizens in the event of the dam failure.

The river expert said that even though any country would take the best possible technology to safely de sign and construct a dam, but the element of dam failure in such a vulnerable terrain cannot be brushed aside under any pretext.

Prof Sharma said the bed gradient of the river in the area where the dam is proposed is extremely steep and maximum discharge of water in that area could reach around 30,000 CUMEC with the average flow ranging from 10 to 15 thousand CUMEC. He said the area is highly seismic and several major earthquakes took place in that area in recent times.

He revealed that in April, 2000 an earthquake of 6.6 on the Richter scale struck the area, which resulted in creation of artificial lakes. The artificial lakes later gave in and caused widespread devastation in Arunachal Pradesh with loss of many lives and property. Again, an earth quake of 6.8 on the Richter scale struck the area in November 2017. That also resulted in massive landslides. For quite some time, the water level of river Brahmaputra has come down and the water too became dirty. Evidently, no one can be sure as to when another mega quake will strike the area and whether the dam will be able to withstand such a quake. The Chinese have not shared the details of the dam design with India and "we do not know whether the dam will have requisite flood storage capacity," he said.

Prof Sharma further said that it is doubtful whether China would share reservoir operation plan with India. He pointed out that in the rainy season, China can release excess water from the dam, which would create devastating floods in India. While, in the lean season the flow of the river depletes to three to four thousand CUMEC and it is mostly glacier flow.

If China plans to store water during the lean season, the base flow of the Brahmaputra may dry up, which will again have severe disastrous impact in Assam and even Bangladesh. To deal with the problem, India has proposed a multipurpose dam to generate 11,000 MW of power in Arunachal Pradesh at Yingkiong.

The focal point for planning the Yingkiong dam should be primarily thrusted upon enormous flood storage capacity with fool proof provision for holding back huge surge waves flood that may rush down from the China dam in case of dam failure. Moreover, as advance action, water storage reservoirs should be created in the major tributaries of the Brahmaputra to meet multiple water uses demand of lean season for drinking, irrigation, pollution control, etc. The numerous water bodies in Assam and Arunachal Pradesh should also be rejuvenated, he advocated.

"We should be prepared for the worst and the Government of India should take the issue with utmost seriousness. Or else, Assam and Arunachal Pradesh may face untold consequences in the future because of the Chinese dam," Prof Sharma added.

By R Dutta Choudhury