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Water levels at China's giant Three Gorges Dam on the Yangtze river are inching closer to their maximum after torrential rains raised inflows to a record high, official data showed on Friday.
With 75,000 cubic metres per second of water flowing in from the Yangtze River on Thursday, the reservoir's depth had reached 165.6 metres (543 feet) by Friday morning, up more than two metres (6.6 feet) overnight and almost 20 metres (65.6 feet) higher than the official warning level.
The maximum designed depth of China's largest reservoir is 175 metres (574 feet).
Authorities raised the discharge volume to a record 48,800 cubic metres per second on Thursday to try and lower water levels, and they might have to increase it again to avoid the possibility of a dangerous overflow.
Wuhan, Nanjing, and Shanghai are all downstream...
(Score: 5, Interesting) by Sulla on Saturday August 22 2020, @04:28AM (2 children)
A few weeks ago there were some leaked internal reports that confirmed that the dam had moved up to a meter (no timeframe given). There are also reports from the original contractors that less steel was used than should have been, cement pours were done too quickly and that by time it went into service it had not all dried (revenue from the electricity was needed), and the anchors were not build to design specifications. It has held this long, so hopefully it continues to do so. Some 200 million people plus would die if this thing went.
Biggest concern I had was a few weeks ago watching the live stream of the dam the water started coming of the tubes weird and there were loud pops, ie signs of cavitation. Because the water level on the downside of the dam are so high if there was cavitation repairs could not be made. After this they started alternating spillways and the output decreased, they then started to alternate between the spillways in what looks like an attempt to even out the damage across the structure so you don't have a total failure, in the hopes that they could make it hold out longer. They also blew out some levies upriver to flood rice and corn fields to reduce pressure on the dam. It is hard to tell because the livestream was looped so you would see the same bug and bird fly by the camera at set intervals, I haven't watched in a week or two because of this.
An issue the dam has had ever since construction is that the power generation turbines have to deal with so much pollution and liter, and it builds up on the upper side of the dam and is rarely cleared. This level of throughput and debris could cause a turbine to fail, further decreasing output. Maintenance has not been done to the turbines in quite a while because shutting down a turbine means less power means less profit.
The battle is to let out enough water not to overload the dam but not allow so much out that it overloads the cities. Downriver the water is already higher than street level but is held back by levies.
Hopefully the rain stops soon
Ceterum censeo Sinae esse delendam
(Score: 2) by FatPhil on Saturday August 22 2020, @10:29AM (1 child)
http://www.youtube.com/watch?v=5O1w2UelZZQ
http://www.youtube.com/watch?v=1AeCyM0DfoM
source: https://brucewilds.blogspot.com/2020/07/chinas-massive-three-gorges-dam-on-edge.html
Handy hint for dictators - if you want to rule a nation, make sure you've got millions of disposables in your population.
Strangely, this is actually good news for Brazil, because equilibria rebalance. Whether the disposables there will ever benefit is another question. (With the answer "obviously not, duh!")
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Saturday August 22 2020, @01:02PM
https://youtube.com/watch?v=nybfjFkDowU [youtube.com]