Dam Failure Case Study: Fontenelle Dam (Wyoming, 1965)

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.

Fontenelle Dam is located on the Green River near La Barge, Wyoming and was originally built in 1964 to provide irrigation water and hydropower for a region of southwest Wyoming. The earthfill embankment structure is 127 feet tall and consists of three zones of shale, sandstone, and limestone. Since its construction in 1964, a five-foot-thick blanket of riprap has been constructed on the dam’s upstream face to provide erosion protection. A concrete diaphragm was installed within the embankment in the 1980’s to protect it against internal erosion. The outlet works system of the dam consists of a conduit through the embankment and two canals located on the left and right abutments. The dam’s primary spillway is a concrete chute located near its right abutment.