Jun 28 2020, 04:58 PM, updated 6y ago
China’s Three Gorges Dam, Largest in World, In Danger of Collapse After Worst Floods in 70 Years
Weeks of heavy rain have put the Three Gorges Dam, the largest hydropower project in the world, in danger of collapse putting 400 million people at risk. The flooding has been described as the worst since 1949 with natural disasters being declared in 24 provinces and municipalities in the southwest and central China, especially in areas near the upper reaches of the Yangtze River and the Three Gorges Dam, causing the reservoir’s water level to exceed the flood control line.
The water level in China’s massive Three Gorges Reservoir reached 147 meters on Saturday, two meters above the flood warning line. Meanwhile, the inflow increased to 26,500 cubic meters per second from 20,500 cubic meters per second on the previous day.
The flood capacity of the dam is being approached, Zhao Yunfa, the deputy chief engineer of the overflow dispatch communications center at the Three Gorges Project, warned people: “”The flood storage capacity of the Three Gorges is limited. Do not pin your hopes on the Three Gorges Dam..”
An estimated 400 million people live downstream of the Three Gorges Dam. The Ministry of Water Resources said that 148 rivers had exceeded warning levels. For the first time in history the Chongqing section of the Qijiang River Basin issued a red warning, signifying a flood of more than 10 meters. More than 40,000 people have so far been evacuated.
German-Chinese hydrologist Wang Weiluo told Radio France Internationale on Monday the dam could collapse at any moment. Wang pointed out that the dam’s design, construction, and quality inspection were all carried out by the same group of people and that the project was finished too quickly using substandard concrete.
Heavy rain is forecast to continue over south China.
Made of concrete and steel, the dam is 7,661 feet long and the concrete dam wall is 594 feet high above the rock basis. The dam caused considerable controversy when it was built, displacing over a million people and submerging large areas of the Qutang, Wu and Xiling gorges for about 600km. The dam flooded archaeological and cultural sites and caused significant ecological changes including an increased risk of landslides. The dam has been controversial both domestically and abroad –while creating a deep reservoir that ocean-going freighters can navigate for 2,250km inland from Shanghai on the East China Sea to the inland city of Chongqing.
Days after the first filling of the reservoir, around 80 hairline cracks were observed in the dam’s structure. It was determined that the submerged spillway gates of the dam might pose a risk of cavitation. In addition, the dam sits on a seismic fault. At current levels, 80% of the land in the area is experiencing erosion. In 2010, NASA scientists calculated that the shift of water mass stored by the dams would increase the length of the Earth’s day by 0.06 microseconds and make the Earth slightly more round in the middle and flat on the poles.
In July 2019, a satellite image of Google Maps appeared to show that the Three Gorges Dam was distorted, sparking concerns that it is at the edge of breaking. The operator of the dam, the China Three Gorges Corp (CTGC), said in a statement then that monitoring data showed the dam was in normal working condition and the project was safe and reliable. Minor deformation happens all the time and it will not affect the dam’s safety as long as it’s within an elastic range, analysts explained then.
https://www.breakingisraelnews.com/153802/c...ds-in-70-years/
Hydrologist Wang: China dam could collapse at any, moment. 400 million people at risk
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