China Floods: Problems with the worlds largest Three Gorges Dam

China’s Three Gorges Dam is the worlds largest dam ever built. The construction of the dam began in 1994. Apart from the purpose to generate electricity, the dam’s purpose was to shield millions from fatal floods.

However, this hasn’t aged well.

The US$28.6 billion project took over 20 years to complete after displacing over a million people from the Yangtze River banks.

The government at that time claimed that the dam would save millions in case of floods, but now the doubts have resurfaced after the region received its heaviest rainfall in over six decades in June 2020 causing the river to over flow.

The floods due to torrential rainfall since June have killed over 150 people and displaced 3.67 million people. Overall 54.8 million people have been affected. The floods have wiped off over US$20 billion.

Despite experts questioning the integrity of the dam, Chinese management center of the China Three Gorges Corp denied any danger to the dam.

READ: Chinese officials rubbish claims of cracks, deformation in the Three Gorges Dam

The structure of the dam is visible from space. It is 181 meters tall and spans 2,335 meters wide across the Yangtze just before the deep, narrow valley gives way to plains.

During dry months the dam holds 22 billion cubic meters of water which is enough to fill 9 million Olympic-size swimming pools. During a ‘once in a century floods’ the dam can hold more than 244 billion cubic meters of water – that is twice the volume of the Dead Sea.

Since the June floods the dam has opened flood gates on multiple occasions drawing criticism that the dam over floods downstream.

Studies by Chinese and foreign researchers over the years have found that the dam’s reservoir is too small to significantly reduce downstream discharge during severe floods.

The dam may reduce the intensity of floods coming from upstream to a certain extent, but it won’t be able to prevent floods caused by intense rainfall on the middle and lower reaches of the Yangtze or the tributaries.

And the flooding in central and southern China this summer, for instance, was caused by rains that fell downstream and didn’t ever go through the dam.

For Chinese rulers, the ability to manipulated waterways has given them a freeway in their reign. This ambition to control water resources has only grown in recent times.

Rulers way back to 1919 had envisioned the Three Gorges dam. Over the years most leaders have worked to making it a reality.

Building the Three Gorges Dam displaced more people than the three largest Chinese dams before it combined. The reservoir submerged two cities, 114 towns and 1,680 villages along the river banks.

1.4 million displaced residents have complained about inadequate compensation and a lack of farmland and jobs after relocation. Many have accused local governments of embezzling resettlement funds.

In 2013, the Chinese government admitted that some of the funds were embezzled.

The dam has also had a serious geological impact. Chinese officials and experts admitted in 2007 that the Three Gorges Dam had caused an array of ecological ills, including more frequent landslides.

In 2003, when the reservoir started to fill for the fist time  landslides began to occur. One of Yangtze’s tributaries spilt off a mountain  killing 24 people, destroying 346 houses and capsizing over 20 boats.

The dam, which sits near two major fault lines, has also been blamed for a surge in earthquakes in the region. Scientists argue that the weight of the large reservoir and the permeation of water into the rocks underneath can trigger earthquakes in regions already under considerable tectonic stress.

According to a study from the China Earthquake Administration, in the six years after the reservoir was filled in June 2003, 3,429 earthquakes were recorded along the reservoir. Prior to the filling of the dam only 94 earthquakes were recorded from January 2000 to May 2003.

The dam has also retained huge amounts of silt which causes erosion downstream.

Over 80 cracks developed on the dam’s concrete after the first fill. Authorities then said the cracks were no threat to the dam. This year, as the floods worsened, rumors over the Three Gorges Dam’s deformation have resurfaced.

READ: Satellite images capture China’s Yangtze river dams discharging floodwater