CS26B - Concurrent Session 26B: Understanding Human Factors that Contributed to the Banqiao and Shimantan Dam Failures

Abstract Description: In August 1975, Typhoon Nina stalled over the Henan Province of China, bringing torrential rainfall, dropping 45% of the typical annual precipitation over only a few days. Such rainfall taxed Banqiao, Shimantan and dozens of other dams in the region, many of which were constructed in a small span of time during the Great Leap Forward, China’s economic and social campaign to industrialize the nation. From August 5 to August 7, water levels behind these dams rose, exceeding safe levels and causing widespread damage downstream, resulting in the third-deadliest flood in history.

Shimantan Dam, built on the Hong River and smaller than Banqiao Dam, reached its capacity around 12:30 AM on the night of August 7. Within half an hour, Banqiao Dam, built on the Ru River, began to overtop. According to Yi Si, a pseudonymous Chinese journalist, Banqiao was regarded as an “iron dam” that could never collapse, and therefore, the severity of the situation was underestimated. In addition, no warning could be issued due to downed telephone lines and a lack of a redundant means of communication.

Once the threat of an imminent dam failure was recognized, workers formed a human chain, trying in vain to repair the embankment. A flood wave with estimated flows of 2.8 million cubic feet per second ripped through the downstream villages and farm fields. Sixty other dams in the region failed that night, killing tens of thousands in the immediate aftermath, and more than 100,000 more in the ensuing months due to starvation, disease, lack of clean water, extreme heat and myriad other causes, precipitating from the dam failure and massive flood waves.

This paper will present a review of available information on the circumstances surrounding the dam failures - including prior to, during, and afterwards, both from personal accounts as well as more official documentation such as that provided by the China Ministry of Water Resources and Electric Power. The literature review focused on gaining a more complete understanding of the mechanism of failure as well as the factors contributing to the failures, including design, construction, and human factors.