By Li Jingru, Vision Times
More than a month after the deadly collapse of the Liulan Reservoir in China’s Guangxi region, questions remain over whether extreme rainfall alone was responsible, or whether shortcomings in the reservoir’s design and management also contributed to the scale of the disaster.
On July 6, the Liulan reservoir in Hengzhou, near Nanning, suffered a major breach following torrential rainfalls, sending floodwaters into downstream communities, killing over 150 people and displacing millions. China’s State Council launched a probe on July 24 to determine the cause of the collapse and examine disaster prevention and emergency response. However, official findings have yet to be released.
Now, in an interview with Vision Times, Germany-based hydrology and environmental expert Wang Weiluo said publicly available information leaves several important questions unanswered.
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Questions over flood-control capacity
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Wang said one of the most striking aspects of the disaster was the footage showing the destructive force of a dam-break flood. “The biggest impact of this dam collapse, or its greatest lesson for Chinese people, is that for the first time ordinary Chinese people saw with their own eyes, through video, just how ferocious a dam-break flood can be,” he said.
He compared the images with the catastrophic 1975 Banqiao Dam failure in Henan, which became one of the deadliest dam disasters in history. More relevant to Liulan itself, Wang also questioned changes to the reservoir’s reported discharge capacity.
He said earlier technical information indicated a maximum discharge capacity of about 2,240 cubic meters per second, while later figures placed it at roughly 1,469 cubic meters per second, a reduction of around 35 percent. “If that discharge capacity had still been there, this should not have happened,” Wang said, arguing that the change deserves examination by investigators.
Public reports indicate that officials began releasing water before the breach after rainfall exceeded forecasts and reservoir levels rose rapidly. The precise condition and performance of the reservoir’s spillways and other flood-control structures will be among the issues investigators need to establish.
Previous reinforcement work
Liulan Reservoir underwent reinforcement work after earlier nationwide dam-safety reviews and was again upgraded beginning around 2009. Wang said the history raises questions about whether previous improvements adequately addressed the reservoir’s vulnerabilities.
RELATED: Guangxi Flood Disaster Raises Questions Over Infrastructure, Emergency Response
He also pointed to conflicting publicly reported figures concerning the reservoir’s flood-season operating level and maximum flood-control level. “The most important thing is that no report has provided information showing that, before the 2026 flood season arrived, Liulan Reservoir lowered its water level to the flood-season limit as required,” Wang said.
Whether the reservoir was maintained at the appropriate level before the extreme rainfall remains unconfirmed. But Wang noted multiple purposes Liulan Reservoir had accumulated over decades.
Originally constructed primarily for irrigation, the reservoir later served power generation and water-supply functions. Aquaculture operations were also introduced. Wang argued that these uses can create competing incentives. “According to China’s Flood Control Law, no matter whether a reservoir is used for fish farming, power generation, or anything else, once the flood season begins, its operation must obey the goal of flood control,” he said.
Maintaining more water can benefit irrigation, electricity generation, and aquaculture, while flood preparedness may require lowering reservoir levels in advance of heavy rainfall. Investigators will need to determine whether such competing objectives played any role in decisions made before the July 6 collapse.
Flood control vs. commercial use
Wang also questioned whether nearby infrastructure projects, including the the Pinglu Canal, may have altered local hydrological conditions. The State Council’s investigation is expected to examine the sequence of events leading up to the breach, the reservoir’s operating decisions, and whether failures in flood control or emergency response contributed to the disaster.
The investigation will also have broader implications for China’s reservoir network, particularly if it finds that outdated infrastructure or management failures played a role in the breach.
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