Plumbing problem at Glen Canyon Dam brings new threat to Colorado River

ATLANTA — Plumbing problems at the dam holding back the second-largest reservoir in the U.S. are spurring concerns about future water delivery issues to Southwestern states supplied by the Colorado River.

Federal officials recently reported damage to four tubes known as “river outlet works” at Glen Canyon Dam on the Utah-Arizona border. The dam is responsible for generating hydropower and releasing water stored in Lake Powell downstream to California, Arizona, Nevada and eventually Mexico.

The U.S. Bureau of Reclamation, which operates the major dams in the Colorado River system, is evaluating issues related to Glen Canyon Dam when Lake Powell reaches low levels. Those issues include problems with the four tubes such as sedimentation and cavitation — when tiny air bubbles develop while water passes through plumbing. Cavitation can cause tears in metal and other mechanical damage.

The Colorado River provides water to seven U.S. states, nearly 30 Native American tribes and two states in Mexico. Years of overuse by farms and cities, and stubborn drought worsened by climate change has meant that much less water flows today through the 1,450-mile river than in previous decades.

Lake Mead and Lake Powell, which store water and are used for recreation and power generation, serve as barometers of the Colorado River’s health. In recent years, they have fallen to historic lows then recovered somewhat thanks to above-average recent winter precipitation and water conservation.

The structural problems at Glen Canyon Dam, first reported by the Arizona Daily Star, could complicate how federal officials manage the river in years to come when hydrologists and others predict Lake Powell will fall below current levels. The damaged tubes sit below much larger ones known as penstocks that normally carry the reservoir’s water. The smaller tubes that make up the “river outlet works” allow water releases at lower reservoir levels.