A report released Wednesday suggests that lower flows on the Colorado River are not only endangering power generation at Glen Canyon Dam, but also impacting the ability to supply water to Nevada, California, in Arizona and Mexico, otherwise known as the lower basin.
Compiled by the Utah Rivers Council, the Glen Canyon Institute and the Great Basin Water Network, The report asks Congress to fund major repairs to the dam, which the groups say would be unable to effectively pump water if the reservoir fell below 3,490 feet.
At 3,490 feet, the dam’s ability to generate electricity for more than 5 million people will be limited, falling under the hydroelectric penstocks that deliver water to the turbines.
But it will also force the Bureau of Reclamation to pump water through the river outlet works, which the report says are outdated and could severely limit deliveries in the lower basin, where nearly 30 million people depend. of the Colorado River.
“Hydroelectric penstocks not only generate hydroelectricity, they are also the primary mechanism by which the Upper Basin fulfills its obligations to deliver water to Lower Basin states and Mexico,” said Zach Frankel, Executive Director of the Utah Rivers Council.
The report comes just weeks after the Bureau of Reclamation released the most extreme water cuts yet – basin states must conserve an additional 2-4 million acre-feet of water, or about a third of the annual consumption of the Colorado River. to flow.
Coincidentally, the report released Wednesday indicates a shortfall of 2 to 4 million acre-feet if the dam infrastructure is not updated.
If the water falls to 3,450 feet, the dam can pump 9.09 million acre-feet per year, still able to supply the approximately 7.5 million acre-feet allocated to the lower basin.
But if the levels continue to drop, there won’t be enough pressure to pump the water through the outlets.
“Due to reduced water pressure as water levels drop, there simply isn’t enough water above the river outlet works to push 7.5 million acre-feet across the system,” Frankel said.
According to a Utah State University analysis, if the level falls to 3,440 feet, the dam can pump 8.28 million acre-feet per year – at 3,430 feet, it can pump 7.41 million acres. -feet, which would be a violation of the Colorado River Compact.
If it falls to 3,400 feet, the Bureau of Reclamation can only supply a measly 3.47 million acre-feet to the lower basin each year, which is nearly the amount of water allocated south of the California alone. And at 3,370 feet, the reservoir would reach deadpool, which means no water would pass through the dam. The only water in the river at this point would come from tributaries and runoff under Lake Powell.
“If you don’t get enough water through Lake Powell, it’s a huge bottleneck,” said Nick Halberg, research and policy analyst for the Utah Rivers Council.
The result would be catastrophic, likely triggering legal battles between states, damaging ecosystems, causing widespread economic damage and straining an already strained water situation in northern Mexico.
The Claims Office own perspective suggests that Lake Powell could drop to just below 3,500 feet in March 2023. And according to a Utah Rivers Council analysis, in coming years the reservoir could see those once-unthinkable levels, where the dam would no longer produce water. electricity or even wouldn’t approach deadpool anymore.
“We don’t have a magic crystal ball, we can’t say better than anyone what the next five winters will hold for the Colorado River Basin,” Halberg said. “…What we can do, however, is look at periods in the past.”
Using past trends as a model – in particular dramatic four-year declines from 2000 to 2004, and a less dramatic period from 2017 to 2021 – levels could drop below the hydroelectric tunnels between December 2023 and December 2026.
And by December 2024 to June 2027, models suggest levels could drop to a point where the upper basin is unable to supply the water allocated to the lower basin, in violation of the Colorado River Compact.
The worst case scenario would be a deadpool by June 2025.
“This river is declining so rapidly that our infrastructure is not ready for it,” said Erik Balken, executive director of the Glen Canyon Institute. “And so there is a real urgency to start looking at alternatives to manage this reservoir at these extremely low levels.”
The report suggests two solutions – one would be to modify the river outlet works, either by widening the existing tubes or by drilling more.
A second option would be to build new bypass tunnels for the Glen Canyon Dam, which would give the system “full flexibility”, Balken said.
“Glen Canyon Dam could be operated down to the natural river level, if the bureau decided to do so,” he said.
The exact cost of these renovations is unclear – a study alone could cost around $2 million, which the Bureau of Reclamation has expressed interest in. And factoring in 2022 dollars, the original bypass tunnels cost around $84 million.
“We don’t really know how much it’s going to cost,” said Kyle Roerink of the Great Basin Water Network. “But I think in this time of crisis, we would be wise to cross our T’s and dot our I’s. I can’t imagine Congress overlooking that.
A Bureau of Reclamation spokesperson said the agency was preparing a statement in response to the report.