Yangtze River flooding question the role played by the massive Three Gorges Dam
Chinese authorities issued more flood warnings for China’s Yangtze River on Friday, as heavy rains were forecast in provinces in the country’s south. At least 141 people have died or are missing and more than 2.2 million relocated due to floods across southern China since June, state-run CGTN reported.
Water levels in the middle and lower portions of the Yangtze River have continued to rise, the official Xinhua news agency reported the Minister for Water Resources E Jingping saying. This followed 12 days of the water in parts of the Yangtze River and its tributaries exceeding alert levels, said the minister.
The Changjiang River Water Resources Commission, which uses the local name for the Yangtze River, on Thursday issued a blue flood warning – the lowest level – for the Three Gorges reservoir, Xinhua reported.
Water inflow to the reservoir on Friday is expected to exceed 50,000 cubic meters a second.
As China counts the costs of its most punishing flood season in more than three decades, the role played by the massive and controversial Three Gorges Dam – designed to help tame the Yangtze river – has come under fresh scrutiny.
Amid some of the heaviest rainfall on record, the Chinese government says the world’s biggest hydroelectric plant has reduced flood peaks, minimized economic losses and slashed the number of deaths and emergency evacuations.
But critics say the historically high water levels on the Yangtze and its major lakes prove the Three Gorges Dam isn’t doing what it was designed for.
One of the major justifications for the Three Gorges Dam was flood control, but less than 20 years after its completion we have the highest floodwater in recorded history, said David Shankman, a geographer with the University of Alabama who studies Chinese floods. The fact is that it cannot prevent these severe events.
Ye Jianchun, China’s vice-minister of water resources, said at a briefing the detailed scheduling of water discharges from reservoirs, particularly the Three Gorges, had been effective in controlling floods this year.
He said 64.7 billion cubic meters of floodwater has been stored in 2,297 reservoirs, including 2.9 billion cubic meters at Three Gorges.
The company running the Three Gorges Project also said on Saturday that downstream water discharges had been halved since Jul 6, effectively reducing the speed and extent of water level rises on the middle and lower reaches of the Yangtze. The total amount of stored floodwater had now reached 88% of the reservoir’s total capacity, it added.
But parts of the Yangtze, its tributaries and major lakes like the Dongting and Poyang have hit record levels anyway.
Fan Xiao, a Chinese geologist and long-standing critic of giant dam projects, said the storage capacity at Three Gorges amounts to less than 9% of average floodwater.
It can only partially and temporarily intercept the upstream floods, and is powerless to help with floods caused by heavy rainfall in the middle and lower reaches of the Yangtze River, he said.
Fan said Three Gorges and other major dam projects could even make flooding worse by altering the flow of sedimentation down the Yangtze. The project’s need to generate electricity has also undermined flood control, he said.