China's Hidden Catastrophe: How 62 Dams Failed in One Night, Killing Hundreds of Thousands

On the night of August 8, 1975, Chen Bin, a local flood-control official in Henan province, stood near the Banqiao Dam as lightning fractured the sky above what he called "a world of rain." Then came a sound he would never forget—a tremendous crash, as if the heavens were collapsing and the earth splitting apart. The dam, built in 1951 and reinforced a few years later with Soviet assistance, had acquired a reputation as the "Iron Dam," a structure considered virtually unbreakable. It was not.

The Banqiao Dam was one of numerous reservoirs constructed as Mao Zedong's newly established People's Republic sought to demonstrate that political power could conquer nature. The building drive intensified during the Great Leap Forward beginning in 1958, when more than 100 reservoirs were reportedly built around Zhumadian alone, in southern Henan. But the policy had a fatal flaw. Chen Xing, a senior Henan water-conservancy engineer, had warned that prioritizing water storage while neglecting drainage on the plains could disrupt the natural water system and increase flood danger. His objections were rejected, and he was accused of making "right-leaning errors." The excessive focus on water storage would worsen what was coming.

Typhoon Nina formed over the Philippine Sea at the end of July 1975, intensified rapidly, and crossed Taiwan before making landfall in China's Fujian province. As it moved inland, the storm weakened, but its remnants became trapped over central China by a blocking weather system. An interaction with another tropical depression channeled exceptional moisture into Henan. The result was rainfall of a magnitude rarely recorded anywhere. Between August 5 and 7, Linzhuang received 1,605 millimeters—close to the world record. Banqiao itself received 1,422 millimeters over three days, including 784 millimeters on August 7 alone. Water poured into Banqiao reservoir at an estimated peak rate of 13,000 cubic meters per second. Its spillways could release only around 1,700 cubic meters per second. The reservoir was gaining water almost eight times faster than it could discharge it.

What followed was a cascade of indecision and failed communication. Technician Hu Defeng later recalled that operating rules required water to be released, but staff had received no clear order from above. Even when an engineer agreed that the gates should be opened, there was no firm instruction on whether to open them fully. Telephones and radio links had been disrupted already. Messages had to be carried by people moving along the dam in torrential rain. A warning sent by a military unit failed to produce a comprehensive evacuation. Signal flares were misunderstood, phones were scarce, and some messengers were themselves swallowed by the flood. Shahedian, located several kilometers below Banqiao, was reportedly the only downstream town to receive a warning more than an hour before the dam breach. Of its roughly 6,000 residents, 827 died. Wencheng and its surrounding villages received no warning before the flood arrived at night. In Weiwan village, 929 of 1,976 people were killed. In Qianhu, 1,397 of 2,200 died.

Shortly after midnight on August 8, water reached Banqiao's protective wall, overtopped the structure, stripped away its earthen shell, and opened a breach across the dam. Approximately 701 million cubic meters of water escaped within six hours. The resulting flood broadened to between 10 and 15 kilometers wide and moved at an estimated 30 to 50 kilometers per hour. Shimantan Dam, 32 kilometers from Banqiao, had already failed after being overtopped. The two major breaches initiated a cascade across the hydrological system. The exact count varies by source, but the US Bureau of Reclamation and several subsequent accounts describe 62 dams failing in total, including Banqiao and Shimantan. Some dams were later deliberately breached to redirect floodwater and protect other reservoirs, further complicating the count.

The first torrent was only the beginning. At least 26,000 people were initially killed due to the floods. The Beijing-Guangzhou railway was severed, roads vanished, and communication with the disaster zone collapsed. Nine days after Banqiao failed, millions of people reportedly remained surrounded by water. On August 13, around two million people were still trapped. In one village, thousands had consumed the available leaves. Some clung to trees for days. Medical teams reached areas where encephalitis and other diseases were spreading, but sometimes they arrived without medicine. By August 18, hundreds of thousands remained stranded in Pingyu, Shangcai, and Xincai. Survivors reportedly ate insects and leaves while contaminated water, extreme heat, and decomposing bodies created conditions for epidemics.

The death toll from famine and disease proved staggering. A Princeton-Tsinghua study reported approximately 100,000 additional fatalities. A much higher estimate of about 230,000 deaths was produced by eight senior Chinese experts and cited by Human Rights Watch in 1995. The exact toll remains contested. Around 10 million people were affected or left without adequate shelter, while entire villages and towns, roads, railway lines, and vast stretches of farmland disappeared underwater. Communist China was then in the final phase of the Cultural Revolution, and information was tightly regulated. Newspapers presented flood-relief propaganda while omitting the dam failures and their human cost. A former official, Chen Zhikai, later told Phoenix TV that no explicit secrecy instruction was necessary. "Usually, when a reservoir collapses and people die, we don't disclose it to the public," he said, describing the prevailing system as one of "reporting good news and not bad news." The scale of the tragedy emerged about 20 years later, while some official records reportedly remained secret for nearly 30 years.

The silence mattered profoundly. If failures remain hidden, engineers and communities elsewhere cannot learn from them. If death figures were suppressed, the human cost of bad engineering design and delayed warnings could never be properly assessed. Banqiao was eventually rebuilt between 1986 and 1993. But its enduring lesson is that an extreme natural event can become a mass tragedy when poor planning, official inaction, and secrecy converge. Half a century later, the disaster has acquired fresh relevance after a flash flood along Nepal's Bhote Koshi-Trishuli river system, close to the Tibet border. While preliminary scientific assessments suggest that an ice-rock or glacier collapse triggered the destructive surge, several Nepali journalists and experts have alleged that China's little-known infrastructure construction along the border might have contributed to the disaster. The question that haunted Banqiao remains urgent: What happens when information about a fast-developing water disaster is buried by a secretive state?