Banqiao Dam Disaster

On August 8, 1975 the Banqiao Reservoir Dam in Zhumadian Prefecture, Henan Province, China, suffered a catastrophic failure, leading directly to the deaths of 26,000 people and affecting more than 11 million people in total. Although some may consider a dam failure to be an engineering failure or man-made disaster, the Banqiao Dam incident is officially considered a natural disaster because of the extreme rainfall and flooding that precipitated the disaster. A typhoon caused more than a whole year's worth of rain to fall in 24 hours. While the dam was engineered to withstand above average rainfall, it did not have the capacity to handle this extreme flooding, which climate experts have labeled a "once-in-a-thousand-years" event. The water peaked at 117.94 meters above sea level, which was 0.3 meters higher than the wave protection wall. The resulting dam breakage released over 701 million cubic meters of water in six hours.

Several measures were unsuccessfully taken to avoid the breakage of the dam in the first place. Workers at Banqiao requested permission to open the dam and thus avoid catastrophic failure, however, the response authorizing them to do so, sent by telegram, failed to reach its recipients. Communications orders also failed in the transmission of evacuation orders, and seven county seats were flooded before they had been fully evacuated, leading to a high death toll. At the time, there was no cohesive early warning system in China for disasters of this kind, which could have prevented much of the damage.

The first response to the disaster was the intentional destruction of several other dams in the area in order to avoid a chain reaction of similar dam breaks. Next, the People's Liberation Army was deployed to for initial disaster aid. Their primary job was to rescue victims who had survived the initial massive release of water and were now trapped by debris, stranded in a dangerous environment, or separated from their homes and families. Next, the government began airdropping supplies of food and medicine to the worst-affected areas. The long-term consequences of this disaster and the reactions to these consequences were largely concerned with famine and epidemics due to destroyed or damaged agricultural land and the spread of water-borne illnesses. All told, it is difficult to say exactly what the death toll, environmental health impact, and economic damage caused by this disaster was. It is also difficult to say how an early warning system and more advanced and organized approach to disaster relief could have mitigated these impacts. However, this scenario does illustrate the dangers that natural disasters can pose to environmental health, especially when disaster preparedness is not functioning at the highest possible level.