Glen Canyon Dam begins relining project as part of the President’s Investing in America agenda

PAGE, Arizona - The Bureau of Reclamation today announced that relining of the river outlet works at Glen Canyon Dam is underway. This project is being funded through a $8.9 million investment from the Bipartisan Infrastructure Law, as part of the President's Investing in America agenda. The project will reline all four outlets and take about one year to complete, ensuring efficient and reliable water deliveries for future generations.

Through the Bipartisan Infrastructure Law, the Bureau of Reclamation is investing a total of $8.3 billion over five years for water infrastructure projects, including rural water, water storage, conservation and conveyance, nature-based solutions, dam safety, water purification and reuse, and desalination. Since the President signed the Bipartisan Infrastructure Law in November 2021, Reclamation has announced $4.2 billion for 575 projects to date.

The outlets, also referred to as bypass tubes, consist of four steel pipes that move water from Lake Powell directly downstream into the Colorado River, bypassing the hydropower generating units.

The original coal-tar coating that covers the inside of the outlets is more than 60 years old, is showing normal signs of wear and tear, and is due for replacement. The original lining was brushed on by hand with spot repairs completed as needed over the years. The project includes removing the old lining and replacing it with an epoxy primer and polysiloxane topcoat, which will be applied by a robotic sprayer. This lining system has been extensively studied in various laboratory tests and successfully applied to numerous infrastructure, including Fontana (North Carolina), Pineview (Utah) and Grand Coulee (Washington) dams.

"It is Reclamation's duty and obligation to operate all of our facilities - including Glen Canyon Dam - in a safe manner and to maintain reliable downstream releases to meet the nation's water and energy needs," said Reclamation's Upper Colorado Basin Regional Director Wayne Pullan. "The relining of the outlets ensures Glen Canyon Dam continues to operate in a manner that meets its congressionally authorized purposes safely and efficiently well into the future."

Glen Canyon Dam impounds Lake Powell, the second-largest man made reservoir in the United States and the largest storage unit in the Upper Colorado Basin. Historically, the dam's outlets have been used sparingly; water is almost always conveyed through the penstocks to produce hydropower before it is released downstream. The outlets are intended to be used when the power plant is unavailable to release water or when required releases exceed the capacity of the power plant. But with lower lake levels, the outlets could be used more frequently, as experienced with the recent implementation of cool-mix flows, which release water from both the penstocks and river outlet works to send cooler water downstream and disrupt the spawning of nonnative fish below the dam.

The potential for increased use of the outlets during low reservoir levels has made this planned maintenance, which was recommended in 2017, a priority.

Reclamation recently found new and minor cavitation damage after operating the outlets at low reservoir levels during a high-flow experiment in April 2023. While relining the outlets won't prevent the risk of additional cavitation when operating at low reservoir levels, Reclamation is working on reducing that risk through the recent development of interim operating guidancefor the outlets and additional analyses.