32. Dam Built to Withstand a “1000 Year Flood” Collapses After Getting Hit With a Flood Twice as Bad as the Worst Expectations
In the 1950s, Mao Zedong announced The Great Leap Forward, an ambitious modernization program to transform China from a peasant society into a global power. As part of that program, the Chinese, with the help of Soviet experts, built a series of dams with the goal of retaining water and providing hydroelectric water. Little emphasis was put on flood control. A chief engineer blew the whistle on the danger, but he was ignored, accused of lacking communist zeal, and banished to the back of beyond.
One of the newly-built dams was at Banqiao, on the Ru River in Henan. 387 feet high, it had a storage capacity of 17.4 billion cubic feet. It was designed to withstand “a 1000-year flood”, that is a flood so severe the odds were that it would happen only once in a millennium. Unfortunately, in early August, 1975, Typhoon Nina struck, stalled over the Banqiao Dam area, and produced flooding double the anticipated 1000-year-level maximum.