For the first time since its completion in 1966, the U.S. Bureau of Reclamation has begun replacing all four original water-control valves at Blue Mesa Dam, a multiyear, $32 million federally funded project officials say is critical to the long-term operation of one of Colorado’s most important water and power facilities.
The work, which began in January, involves replacing two ring follower gate valves and two butterfly valves — massive components that control how water moves through the dam and into power generation systems and the Gunnison River below. Reclamation officials say the upgrades will ensure reliable water delivery for irrigation, flood control and hydropower generation well into the future.
Standing 390 feet tall, Blue Mesa Dam impounds the Gunnison River to form Blue Mesa Reservoir, the largest body of water entirely within Colorado with a capacity of about 940,000 acre-feet. It is the first of three major dams in the Bureau of Reclamation’s Wayne N. Aspinall Unit of the Colorado River Storage Project, which also includes Morrow Point and Crystal dams. The unit provides water storage, flood control and hydroelectric power for communities and agricultural users throughout the Upper Colorado River Basin.
Blue Mesa’s powerplant alone produces roughly 86 megawatts of electricity, helping power homes and businesses across the region.
Work on the valve replacement began with the removal of the first ring follower gate — a device roughly 18 feet long, 7 feet wide and weighing about 14 tons. A hydraulic hoist adds another 12 tons of machinery. To safely remove the gate, crews first installed a blind flange, a heavy steel plate that temporarily seals the opening and holds back water in the penstock, the large pipe that carries water through the dam. The removed gate and associated parts were shipped to California for refurbishment and are expected to return for reinstallation in August.
Later this fall, once irrigation demands ease, the blind flange will be removed and normal operations restored, and crews will begin work on the second ring follower gate and the two butterfly valves.
“This work is complex,” said Blue Mesa Plant Supervisor Eric Langely. “We must maintain minimum river flows downstream, avoid disruptions at Morrow Point and Crystal dams, and manage drought-related constraints — all while working inside a dam built nearly 60 years ago.”
A dam with deep roots
Blue Mesa Dam was constructed as part of the Wayne N. Aspinall Unit, a major component of the federal Colorado River Storage Project authorized in the 1950s to regulate water in the Upper Colorado Basin for agricultural, municipal and power uses. Construction of the dam began in 1962 and was completed in 1966, with the power plant coming online in 1968.
The reservoir stretches roughly 20 miles along the Gunnison River and is a centerpiece of the Curecanti National Recreation Area, attracting anglers, boaters and campers. It also serves as a cold-water source managed under environmental agreements to support downstream ecosystems, including through minimum flow requirements in the Black Canyon of the Gunnison National Park.
As the first and largest of the Aspinall dams, Blue Mesa has endured decades of drought cycles and changing water demands. In recent years, it has been part of regional efforts to balance storage while meeting legal obligations to supply reservoirs such as Lake Powell with water during periods of shortage.
Balancing operations and demands
Officials said challenges during the valve project include ensuring continued water deliveries for irrigation and municipal use, maintaining river flows that meet environmental targets, and coordinating operations with the downstream Morrow Point and Crystal dams, which also play significant roles in water storage and power generation.
The Aspinall Unit operates under a comprehensive Record of Decision that governs releases to meet agricultural, municipal and environmental needs from spring through winter. Water levels in Blue Mesa fluctuate annually, influenced by snowpack, runoff forecasts and water use demands in the upper basin.
Despite these complexities, project leaders say the valve replacements are essential to maintain operational flexibility and safety.
“This upgrade will keep Blue Mesa Dam operating safely and efficiently for decades to come,” Langely said.
