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French Canyon Dam

French Canyon Dam
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The dam is a zoned earth fill structure with a structural height of 74 feet, a crest length of 1150 feet, and a crest width of 15.5 feet at crest elevation 2170 feet. The upstream face has a 2.5 to 1 slope and is protected by 3 feet of riprap. The downstream face has a 2 to 1 slope and is protected by 18 inches of riprap. The embankment consists of a silt core, progressively coarser zones of sand and gravel, and a protective layer of riprap on the outer slopes. The dam foundation consists of basalt on the south abutment, cemented sand and gravel (conglomerate) in the center of the dam, and basalt again on the north abutment. A core trench 32 feet wide at the bottom with 1:1 side slopes was excavated across the entire length of the dam. This trench was backfilled with silt core material and sand filters. The dam includes an extensive drainage system, which exits into the drainage trench downstream of the dam. The embankment is terminated at the northern end by a concrete retaining wall which is anchored to the rock with post-tensioned anchor bars. At the south end, a section of rock-fill was placed on the south (right) abutment just upstream of the dam for erosion protection.

Last updated: Mar 11, 2009