Fontenelle Dam - Construction

Construction

Development of the upper Green River basin was included in a 1946 Bureau of Reclamation report on the Colorado River basin. A 1950 supplementary report dealt with details of the proposed Seedskadee Project, followed by another addendum in 1953. The Colorado River Storage Project, including the Seedskadee Project, was authorized by Congress in 1956. Initial planning was completed in 1959, and amended in 1961 to increase the capacity of Fontenelle Reservoir to 345,400 acre feet (0.4260 km3), making the construction of a powerplant feasible. Work was stopped on irrigation infrastructure in 1962. The dam featured unusually large outlet works, capable of discharging 18,000 cu ft/s (510 m3/s) (compared with a spillway capacity of 20,200 cu ft/s (570 m3/s)) because the outlet works could be increased in size at lower cost than the spillway.

The first element of construction at Fontenelle Dam was the building of the Fortenelle community, the base camp for construction, with work starting in 1961 to build prefabricated relocatable houses for dam workers. The construction contract for the dam was awarded on June 13, 1961 to Foley Brothers, Inc. and the Holland Construction Company of St. Paul, Minnesota, with construction starting on June 30, at a cost of $7.9 million. The surface of the bedrock at the dam's base was found to be fragmented, so the cut-off trench intended to preclude water infiltrating under the dam, was deepened by 6 feet (1.8 m). The exposed rock was not prepared or smoothed with concrete. The foundation grouting required an unusually large amount of material to fill cracks in the upper 65 feet (20 m), with additional grouting required at the right abutment and outlet works. Work on the dam was completed by the end on 1963, with final completion on April 24, 1964. Work on the powerplant started in 1963, with completion in 1965.