Ye Jianchun, China’s vice-minister of water sources, mentioned at a Monday briefing the “detailed scheduling” of water discharges from reservoirs, notably the Three Gorges, had been efficient in controlling floods this yr.
He mentioned 64.7 billion cubic metres of floodwater has been saved in 2297 reservoirs, together with 2.9 billion cubic metres at Three Gorges.
As many as 33 rivers in China have risen to their highest ranges in historical past in the course of the present wave of floods, Ye mentioned, as areas throughout the nation brace for one more “grim” week of torrential rain.
He mentioned 433 rivers – in addition to main lakes just like the Dongting, the Poyang and the Tai – have all risen past their warning ranges because the flood season started in June.
“Going into the important thing flood-prevention interval of late July to early August, the present traits stay grim on the Yangtze and the Lake Tai basins,” he mentioned, including that the belts of heavy rain which have lashed central China would finally head north.
Common rainfall has been at its highest since data started in 1961. The Emergency Ministry mentioned 141 folks have been useless or lacking as of final Friday, with financial losses at round 60 billion yuan ($12.three billion).
The corporate operating the Three Gorges Undertaking additionally mentioned on Saturday that downstream water discharges had been halved since July 6, “successfully decreasing the velocity and extent of water stage rises on the center and decrease reaches of the Yangtze”. The entire quantity of saved floodwater had reached 88 per cent of the reservoir’s complete capability, it added.
However components of the Yangtze, its tributaries and the foremost lakes have hit file ranges anyway.
Fan Xiao, a Chinese language geologist and long-standing critic of large dam tasks, mentioned the storage capability at Three Gorges quantities to lower than 9 per cent of common floodwater.
“It may solely partially and briefly intercept the upstream floods, and is powerless to assist with floods attributable to heavy rainfall within the center and decrease reaches of the Yangtze River,” he mentioned.
Fan mentioned Three Gorges and different main dam tasks may even make flooding worse by altering the stream of sedimentation down the Yangtze. The venture’s have to generate electrical energy has additionally undermined flood management, he mentioned.
“When folks solely think about using reservoirs to resolve flood-control issues, they typically overlook and even weaken the pure capacity of rivers and their lakes to manage floods,” he mentioned.
Shankman mentioned that the Three Gorges Dam helped alleviate flooding throughout regular years, however that it was at all times prone to be weak to extra excessive climate, an issue that was exacerbated by shrinking flood plains downstream.
“The Three Gorges Dam reservoir doesn’t have the capability to considerably have an effect on probably the most extreme floods,” he mentioned.
“Floodwater storage alongside the center Yangtze is much less due to stronger levees which are much less prone to fail,” he added. “Each of these issues are at play right here. This was predictable.”