1975 Banqiao Dam failure
1975 CE.
Shown on the map at 32.980°, 113.587°.
In August 1975, the Banqiao Dam and 61 others throughout Henan, China, collapsed following the landfall of Typhoon Nina. The ensuing flood was among the deadliest floods in China, and was the third-deadliest flood in history which affected 12,000 km2 (3 million acres) with a total population of 10.15 million, including around 30 cities and counties, with estimates of the death toll ranging from 26,000 to 240,000. The flood also caused the collapse of 5 million to 6.8 million houses. The dam failure took place in the context of the Cultural Revolution. Many of the dams that collapsed were originally constructed with the help of Soviet advisors. Many were built during the Great Leap Forward. The construction of the dams focused heavily on the goal of retaining water and overlooked their capacities to prevent floods, while the quality of the dams was also compromised due to the Great Leap Forward. The Banqiao dam had been designed for a calculated one in a thousand year rainfall event of 300 mm per day; however, more than the normal yearly rainfall (1,060 mm) fell in just one day near the typhoon center.
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