How China’s dam may have worsened Wuhan flooding
Hubei houses the giant Three Gorges dam to regulate the flow of the Yangtze, Asia’s longest river. The project, world’s largest gravity hydroelectric system, was constructed between 1994-2012, but, has a history of controversy.
The initial epicentre of the new coronavirus, Wuhan in China, is now bracing for severe flooding, the second calamity to be striking the city of 11 million within a year.
Chinese authorities have issued red alerts for parts swamped by torrential rains.
The landlocked central province of Hubei, where Wuhan is located, is one of them.
CHINA’S CONTROVERSIAL DAM
Hubei houses the giant Three Gorges dam to regulate the flow of the Yangtze, Asia’s longest river.
The project, the world’s largest gravity hydroelectric system, was constructed between 1994-2012.
It consists of a 2,309-meter-long and 185-meter-high dam, a five-tier ship lock, and 34 hydropower turbo-generators.
But the project has a history of controversy.
Environmentalists have long alleged that the showcase reservoir exposed areas, both upstream and downstream, to heightened risks of landslides, flooding and damage to the river ecology.
“The dam also was intended to protect millions of people from the periodic flooding that plagues the Yangtze basin, although just how effective it has been in this regard has been debated,” according to Britannica.
But the encyclopaedia notes how some 1,200 sites of historical and archaeological importance that once lined the middle reaches of the Yangtze River vanished as floodwaters rose after the second phase of its construction completed some 17 years ago.
IMAGE ANALYSIS OF THREE GORGES
Scrutiny of satellite images suggests the floodwaters were released from the dam’s spillways prematurely this year.
Also this year, China’s Central Meteorological Observatory issued a 30-day rainstorm warning.
This long duration is rare, given hi-tech monitoring at all hydrographical checkpoints.
That said, the warning about heavy rains and thunderstorms for June 30-July 30 covered all parts of China and Hong Kong.
The catchment area of the Three Gorges Dam, located at the site of the Zhongbao Island, has grown tall over the last five years because of high mountains around.
Satellite images indicate that the reservoir could have absorbed more rainwater in the catchment area as it did before.
Remember, the variations in the water levels are generically compared with what remains of the Zhongbao Island — a large viewpoint with a road emanating from the southern end of the dam.
The level of the water as observed in an old image of October 27, 2017, was much higher, by at least 15 meter, than its present status. Still, no floodgates were opened and electricity generation continued as usual back then.
The latest images, however, indicate that the floodgates were released as early as June 24, 2020 and remained open even till Thursday.
China’s state-controlled media reported flooding in the Yangtze on July 2.
“At the Three Gorges Dam in Hubei Province, the flood’s inflow rate reached 50,000 cubic meters of water per second. As a result, the dam opened three flood discharging outlets to ease the flood’s impact on the river’s lower reaches,” said a report on CGTN, a mouthpiece of the communist regime.”Since June 29, the outflow of the Three Gorges Dam has been controlled at an average daily rate of 35,000 cubic meters per second, reducing up to 30 percent of the Yangtze’s peak discharge, which has effectively relieved the pressure of flood control on the middle and lower reaches of the river,” it added.
GREATER CHALLENGE FOR WHO INVESTIGATORS
Meantime, the flood situation may pose a tougher challenge to World Health Organization, which is preparing to investigate the origins of Covid-19.
According to a WHO statement, two of its experts are headed to the Chinese capital to lay the groundwork for a larger investigation into how the deadly virus jumped from animals to humans in Wuhan.
(Col Vinayak Bhat (Retired) is a consultant for India Today. A satellite imagery analyst, he served in the Indian Army for over 33 years)