(TibetanReview.net, Apr29’21) – China’s plan to build in occupied Tibet during its current five-year plan a dam so big that its electricity generation capacity will reach 70 gigawatts, about three times that of the Three Gorges Dam, could be delayed by a lake formed by a 2018 landslide, reported the scmp.com Apr 18.
The Yarlung Tsangpo river dam project was approved by China last year and included in the 14th five-year plan with a deadline of 2035.
The report noted that in 2018, a landslide caused by a melting glacier blocked the Yarlung Tsangpo – the upper stream of the Brahmaputra River – at the Sedongpu Basin in Milin County (in Nyingtri Prefecture of TAR). It formed a lake containing about 600 million cubic metres of water. With the river spilling over the top at present, the dam could collapse at any time.
And the Sedongpu lake sits just a few dozen kilometres upstream from the planned construction site of the super hydropower plant. With so much water hanging overhead, no construction workers can move in to clear the ground. To build the big dam, they must get rid of the small dam formed by the landslide first, the report noted.
China’s top experts in civil engineering, glacier study and landslide prevention collected a large amount of data on the site using drones and other advanced equipment and were asked by authorities to come up with a solution.
“The situation is very difficult. There is not an immediate solution yet,” Xing Aiguo, a professor of civil engineering at the Shanghai Jiao Tong University who was involved in one of the studies, has said.
The report said the experts could not find a way to strengthen the landslide dam or remove it safely. Worse still, they found similar disasters would likely happen again in the same area, thanks to climate change.
“The area is large and there are many glaciers,” Xing has said. He has said an engineering method if found at all could be technically challenging and costly.
A quarter of the glaciers on the Tibetan Plateau have disappeared since the 1970s, and two-thirds of the remaining will be gone by the end of the century, the report said, citing an estimate by the United Nations’ Intergovernmental Panel on Climate Change.
The report said some Chinese scientists had proposed that instead of building a super dam, a 16km-long tunnel could be dug through one of the high mountains in the Yarlung Tsangpo valley. The water could be directed into the tunnel to push electricity generating turbines. This scheme would reduce the power output to 50GW – or about twice that of the Three Gorges Dam – but reduce the risk of damage from landslides or other natural disasters.
China’s Yarlung Tsangpo dam plan has caused serious concern in downstream India, which fears that Beijing could use the dam to cut off India’s much-needed water supply, or otherwise cause floods by excessive release of water.