Wachi Dam and Folsom Dam

Abstract

The failures at the Wachi Dam on the Yura River in Japan on July 2, 1967 and at the Folsom Dam on the American River near Sacramento, on July 17, 1995 are analyzed in light of the development of the self-excited coupled-mode instability mechanism. In both failures vibration of the gate was either suspected or noted by eyewitnesses. An exploratory study of how the predictions from the theory of the self-excited coupled-mode instability mechanism fit with the limited known facts is undertaken. The theoretical predictions from self-excited coupled-mode instability theory are found to explain well these two failures and are consistent with the reported circumstances surrounding the failures.