Dam Failure Case Study: Malpasset Dam (France, 1959)

DamFailures.Org is an ASDSO project that provides individual dam failure case studies and lessons learned as a resource for dam safety engineers, dam operators, owners, regulators, managers, academia and students to help prevent future incidents.

Malpasset Dam was a concrete arch dam located on the Riveria in the Cannes District near Fréjus, in Southern France. Exhibiting curvature in both the plan and section directions, the double-curvature arch structure spanned the Reyran River. At the time of completion in 1954, it was reported as the thinnest arch dam of its height (218 feet) with a maximum thickness of 22.2 feet. The dam was equipped with one un-gated, notched spillway at the center of its 736-foot-long crest. Because the planned left abutment of the dam (from an upstream perspective) was higher than site topography, a large dihedral thrust block was placed below the dam to raise it to the necessary height. Construction of the dam began in 1952 and the first filling of the reservoir began on April 20, 1954. Approximately five years later, when the first filling was nearly complete, Malpasset Dam failed on December 2, 1959 after the area experienced several days of heavy rain and high winds. The sudden failure of the dam resulted in the death of 421 people when emergency rescue attempts were thwarted due to the inaccessibility of the town’s flooded roadways and access routes.