China: Largest dam imperiled by flooding

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By Mark Ellis –

Flooding in Guilin, June 2020

Heavy rain and flooding in June have put the Three Gorges Dam at risk, placing 400 million people living downstream in danger.

The flooding in southwest and central China is said to be the most severe since 1949. Natural disasters have been declared in 24 provinces and municipalities, especially near the upper reaches of the Yangtze River.

Massive in size, the Three Gorges Dam is 7,661 feet long and 594 feet high. It caused considerable controversy when it constructed in Hubei Province, because 1.2 million people were displaced, along with cultural, historical, and archaeological sites.

Workers standing on top of Three Gorges Dam

As the water level in the reservoir created by the dam reached six feet above the flood warning line, Zhao Yunfa, the deputy chief engineer of the dam’s communications center issued a stark warning:

“The flood storage capacity of the Three Gorges is limited. Do not pin your hopes on the Three Gorges Dam.”

Downstream, for the first time in history the Chongqing portion of the Qijiang River Basin issued a red flag warning, indicating a flood of more than 32 feet. More than 40,000 people have been evacuated there.

Major cities face flooding if the dam collapses

German-Chinese hydrologist Wang Weiluo said on June 22nd the dam could collapse at any moment.

“Wang pointed out that the dam’s design, construction, and quality inspection were all carried out by the same group of people and that the project was finished too quickly using substandard concrete,” according to Breaking Israel News. He said the dam is composed of dozens of concrete blocks, not connected to the bedrock below but merely sitting on top.

Construction of Three Gorges Dam

Additionally, western experts who inspected the dam during construction said the steel bar welding was done improperly. Chinese officials said their criticisms amounted to racism.

A few days after the reservoir was filled for the first time in 2009, about 80 hairline cracks were observed in the dam’s structure. It was determined that the submerged spillway gates of the dam might pose a risk of cavitation, forming an empty space or void that would reduce structural integrity. In addition, the dam sits on a seismic fault.

When the dam was first constructed, state media claimed the dam could withstand the worst flood in 10,000 years. Later, they revised that projection to 1,000 years. More recently, they lowered the forecast to 100 years.

In 2018, a satellite image from Google Maps revealed the Three Gorges Dam, originally straight when viewed from above in 2008, now follows an uneven, wavering line, bulging outward in places.

Satellite photos taken in 2008 (left) and 2018.

Chinese authorities dismissed the photos, claiming they were caused by satellite imaging problems.

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