Dam’s broken infrastructure poses water dangers for Southwest

Federal officers have found injury inside Glen Canyon Dam that would drive limits on how a lot Colorado River water is launched at low reservoir ranges, elevating dangers the Southwest may face shortages that had been beforehand unexpected.

The injury was lately detected in 4 8-foot-wide metal tubes — known as the river outlet works — that permit water to cross by means of the dam in northern Arizona when Lake Powell reaches low ranges. Dam managers noticed deterioration within the tubes after conducting an train final 12 months that despatched massive flows from the dam into the Grand Canyon.

To cut back dangers of further injury, federal Bureau of Reclamation officers have decided that flows ought to be lowered within the occasion of low reservoir ranges. The infrastructure issues in one of many nation’s largest dams have created new problems as water managers representing seven Western states negotiate long-term plans for decreasing water use to handle the river’s power supply-demand hole and adapt to the consequences of local weather change.

“Due to the dam’s design, there are actual structural dangers below low elevations that would probably go away stranded as a lot water in Lake Powell as California’s largest reservoir, Lake Shasta,” stated JB Hamby, California’s Colorado River commissioner.

Such a situation may result in important surprising cuts in water deliveries to California, Nevada, Arizona and Mexico.

“There are a few methods to take care of this, absent an infrastructure repair,” Hamby stated in an electronic mail. “One, cut back releases to Arizona, California, Nevada, and Mexico.”

However he stated that may very well be a violation of the 1922 Colorado River Compact, which ensures that the states within the river’s decrease basin obtain a sure amount of water.

A second choice, Hamby stated, would have an effect on the 4 states within the river’s higher basin: Colorado, Wyoming, Utah and New Mexico. He stated that would embrace decreasing water use within the higher basin states or releasing water from upstream reservoirs.

“An engineering answer is preferable to each of these choices,” Hamby stated.

Efforts to investigate potential fixes seem like within the early phases.

The issues got here to mild at a assembly in Arizona final month. Brenda Burman, normal supervisor of the Central Arizona Mission, introduced a diagram exhibiting the dam’s eight massive tubes, known as penstocks, that water usually passes by means of, in addition to the smaller outlet pipes that allow water releases at low reservoir ranges.

“They’ve some unknown points about how these river outlet works would carry out. That’s very troublesome new data to listen to,” Burman stated.

She stated officers discovered sediment, “thinning within the pipes” and “cavitation.” Cavitation refers back to the formation and collapse of air bubbles in flowing water and is thought to wreck propellers, pumps and different buildings. Below sure circulate circumstances, cavitation can pit and tear into metallic, damaging the infrastructure.

Federal officers are analyzing the best way to handle the issues, Burman stated, including that the Bureau of Reclamation is “identified for having the ability to provide you with engineering options to engineering issues.”

“We very a lot anticipate to be working with Reclamation within the coming months to research precisely what will be achieved,” she stated.

The issues with an important a part of the dam’s water-delivery system, which had been first reported by the Arizona Each day Star, have raised new questions on what kind of repair could be handiest, how a lot it will price, and the way lengthy repairs may take.

The Colorado River provides water utilized by cities, farms and tribal nations throughout seven states and northern Mexico. The river has lengthy been overallocated, and its common circulate has declined dramatically since 2000. Analysis has proven that international warming is intensifying drought years and contributing considerably to the lowered flows.

The water degree in Lake Powell, the nation’s second-largest reservoir, now sits at 33% of capability — its floor about 68 toes above the lowest degree at which the dam can proceed producing electrical energy. The snowpack within the higher Colorado River Basin this 12 months has been above common, and the snowmelt will give reservoir ranges a lift for now.

However long-term projections present that substantial reductions in water use will likely be essential within the coming years to cut back dangers of reservoirs reaching critically low ranges.

The infrastructure issues at Glen Canyon Dam add one other layer of problems and uncertainty.

The Bureau of Reclamation detailed a few of the company’s preliminary steps in a March 26 memo. Richard LaFond, director of the company’s Technical Service Heart, wrote that if the reservoir had been to say no beneath the minimal degree for producing electrical energy, “there are issues with counting on the river outlet works.”

The most recent federal projections present the reservoir is predicted to stay above that degree for the subsequent two years.

LaFond stated his crew is utilizing scale fashions in a laboratory to review how the problems may very well be addressed.

The Bureau of Reclamation responded to questions from The Instances by electronic mail, saying the outlet tubes “weren’t designed for use indefinitely to ship water at low elevations.”

“It is very important be aware that our information will enhance as time goes on and that we might have to regulate our actions, as applicable, per greatest rising data, engineering requirements, and present science,” the Bureau of Reclamation stated.

The company’s officers stated whereas they research the problems, they plan to do upkeep that may embrace “pipe recoating.” They stated they don’t but have price estimates for fixes.

Lake Powell has shimmered between purple canyon partitions alongside the Arizona-Utah border since Glen Canyon Dam was accomplished within the Nineteen Sixties.

Environmental activists, who’ve lengthy urged federal officers to take into account draining the reservoir, stated the dam’s inside issues create severe dangers of unanticipated water shortages in Southern California, Arizona, Nevada and Mexico.

“We have to have a dialogue about how the dam’s vintage plumbing may have an effect on 25 million individuals downstream in low water circumstances — particularly persistent low water circumstances, as we predict,” stated Kyle Roerink, govt director of the Nice Basin Water Community. “We want the bureau to step up and assist us all have a greater concept of the best way to repair it.”

Roerink’s group, along with the Utah Rivers Council and Glen Canyon Institute, had warned in a 2022 report that the “antiquated plumbing system inside Glen Canyon Dam represents a legal responsibility,” with dangers of exactly the kind of issues which have come to mild.

Roerink known as for the Biden administration to carry its evaluation of Glen Canyon Dam’s vulnerabilities into its ongoing technique of contemplating long-term plans for decreasing water use.

The Bureau of Reclamation plans to investigate alternate options for brand new guidelines to control river administration beginning after 2026, when the present guidelines expire.

The federal authorities has acquired separate proposals from the higher and decrease basin states, tribes, environmental teams and water researchers.

The danger of a choke level at Glen Canyon Dam not solely will increase uncertainty, Roerink stated, but in addition “units up potential for extra acrimony.”

He stated there ought to be an open dialogue, as a part of the federal assessment, to investigate the issue and what will be achieved about it.

That will “create a possibility for the general public to vet, scrutinize and perceive every thing that the bureau is aware of, and likewise take into account the identified unknowns as properly,” Roerink stated. “Let’s speak about uncertainty, and what that would imply.”