Gold Hard Hat Award

Outstanding Environmental Project

Since its construction in 1911, the Price-Stubb Dam near Palisade has prevented migratory fish species, several of them endangered, from traveling to upstream habitats along the Colorado River.

U.S. Bureau of Reclamation-led environmental and engineering studies indicated that a fish-passage facility would significantly improve fish migration around this historic, though abandoned, diversion dam. However, building a fish ladder at this location would require that the fast-flowing Colorado River be completely diverted around the dam and the proposed fish ladder for up to six months to create a dry working environment for construction crews.

Originally constructed for diverting water into the Mesa County and Palisade Canals, the Price-Stubb Dam is a 325-ft-wide, 8-ft-high, low-head concrete roller dam spanning the width of the river. The actual site spans 500,000 sq ft along and within the previous waterway of the Colorado River along Interstate 70, a few mi east of Palisade.

Working with the BOR and Kissner General Contractors, Kleinfelder, a nationwide engineering and project management consulting firm, prepared a detailed hydrologic and hydraulic analysis to select an appropriate design flow and size a diversion channel and the upstream and downstream cofferdams. The work in the river was planned for fall 2007 through early spring 2008, when river flows are at their historically lowest and most manageable levels.

Once the river was diverted, construction crews began work on the fish ladder, as well as repairs to the river bottom. The 600-ft-long passage is made up of 190 concrete cylinders placed in a chevron pattern of 38 separate baffle arrangements consisting of five cylinders each. The center cylinders are spaced 15 ft apart along the fish ladder. These provide a cascading effect of pool and drop that allow the fish a chance to rest on their upstream migration.

The Price-Stubb Dam diversion channel was closed, cofferdams were removed, and the Colorado River was diverted back to its normal path in late April, just in time for a fairly pronounced spring runoff. The dam was the last remaining obstacle on the river between Lake Powell in southern Utah and Rifle, Colo., at the upper end of the fishes’ critical habitat.

Upper Colorado River Recovery Implementation Program
Palisade

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