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Az to lose nearly a 1/4 of share of Colorado River water as Lake Mead hits 'historic' low

Az to lose nearly a 1/4 of share of Colorado River water as Lake Mead hits 'historic' low

Feds to cut 21% of Arizona's annual allotments as levels point to extreme shortages

  • The light-colored exposed 'bathtub ring' of formerly submerged shoreline in Lake Mead was already evident in this 2020 photo of the Hoover Dam and diminishing reservoir behind it.
    Ross Rice/The Water Desk and Lighthawk The light-colored exposed 'bathtub ring' of formerly submerged shoreline in Lake Mead was already evident in this 2020 photo of the Hoover Dam and diminishing reservoir behind it.

Arizona will face a drastic cut in the amount of Colorado River water delivered from Lake Mead after federal officials announced Tuesday that the state will lose 21% of its annual allotment next year. It’s the biggest reduction among Colorado River users as levels in reservoirs at Lakes Mead and Powell continue to decline.

The Bureau of Reclamation is making the cuts to “meet out inherent mission to protect the (Colorado River) system and the ensure the cities, agricultural communities, tribal nations and the environment are sustained, not next year, but for the future,” officials said.

“The (Colorado River) system is approaching a tipping point and without action, we cannot protect the system and the millions of Americans who rely on this critical resource,” BOR Commissioner Camille Touton said Tuesday. “Protecting the system means protecting the people of the American West.”

The decision to cut water allotments comes after a 24-month study by the agency published Tuesday found that shortages in Lake Mead will hit historic extremes by January 2023.

The lake is now less than a quarter full, which marks a 5 percent drop-off in its total capacity from last year. The lake, just a half-hour outside Las Vegas, will reach a Level 2A shortage for the first time since it was built in the 1930s.

Water levels in Lake Mead and Lake Powell, near the Arizona-Utah border, has been declining since the mid-1990s because of a 23-year drought and low runoff conditions in the Upper Colorado River Basin, both “accelerated by climate change,” according to the Bureau of Reclamation.

States in the Colorado River Basin were given 60 days in June to come up with an emergency plan to cut their water usage by 2 to 4 million acre-feet of water a year, Toutan told the U.S. Senate in June. Arizona's annual allotment from the Colorado River is 2.8 million acre-feet of water,  and that will be cut by nearly 600,000 acre-feet in 2023.

States missed that 60-day deadline, Touton said Tuesday to reporters, which will force the federal government to decide if further reductions of water allotments will be necessary. Touton avoided saying whether that cuts would be enforced through a agreement among Colorado River users or if Reclamation will enforce later cuts.

'The lifeblood of the American West'

Nevada and Mexico will see cuts to their water allotments as well, the Bureau of Reclamation announced, but Arizona is the Colorado River user most impacted by the cuts as the state is one of the greatest users of water from the river and its tributaries.

Last year, Arizona saw an 18 percent cut in the Lake Mead water allotment during a Tier 1 shortage. This year, the added 3 percent reduction makes the state the biggest loser among Lower Basin water users as the federal government tries to bolster the entire Colorado River System.

The Colorado River starts in the Rocky Mountains, where it’s fed by melting snow during the spring, and runs 1,450 miles across the U.S. Southwest to the Gulf of California in Mexico. Touton called it “the lifeblood of the American West” during Tuesday's press conference.

Water from the river drains into two major basins: the Upper Basin reaching north to Wyoming and ending just south of Lake Powell, and the Lower Basin that spreads from the edges of the Nevada, California and Utah, across nearly all of Arizona to New Mexico and parts of Mexico. Arizona takes up most of the Lower Basin.

The river and its smaller tributaries — such as the Santa Cruz River in Tucson and the Gila River — provide water to more than 40 million people in the U.S., Mexico and in all of Arizona’s 22 federally recognized tribes for municipal and residential uses but also to power farming and electricity throughout the region.

The river’s water irrigates more than 5.5 million acres of land, sustaining agriculture in the region, and offers one the largest sources of renewable energy in the Western U.S. through hydroelectricity generated by dams, such as the Glen Canyon Dam near Lake Powell and the Hoover Dam near Lake Mead.

Lake Mead is forecast to see water levels drop from just less than 25 percent of its total capacity to “17 percent of its capacity as early as summer 2024,” said Daniel Bunk, chief of Reclamation’s Boulder Canyon Operations Office.

Such a drop would bring water levels in Lake Mead below 1,000 feet. A deadpool would occur when the water elevation is less than 900 feet, with no water flowing downstream and the Hoover Dam no longer able to generate electricity.

Giving a dam

Water is delivered to Maricopa, Pinal and Pima counties from Lake Mead through the Central Arizona Project. Lake Mead is the biggest reservoir in the U.S., and Lake Powell is second. Lake Powell is also less than a quarter full, according to Reclamation. The water levels of both reservoirs are at just 28 percent of their combined total capacity.

Lake Powell is used to hold back water flowing south along the Colorado River from the Upper Basin. The reservoir and Glen Canyon Dam deliver water, generate electricity and sustain recreation areas in Arizona, California and Nevada, just like Lake Mead. While water allotments are being cut from Lake Mead, less water will flow out of the Glen Canyon Dam and Lake Powell as well to account for the worsening shortage conditions. 

Water levels at Lake Powell are expected to fall to just 32 feet above “minimum pool power” or the amount of power needed in the reservoir to generate hydroelectricity through the Glen Canyon Dam.

Touton even suggested on Tuesday that the dam could be decommissioned, though she didn’t answer the question directly despite several attempts by reporters to get clarification.

Arizona, Nevada and Mexico are the only Colorado River users losing portions of their water allotments. Nevada will see an 8 percent loss in its annual allotments. Mexico will see a 7 percent loss.

Colorado River users agreed to have their allotments cut based on reductions in Lake Mead when they signed the 2019 Drought Contingency Plan for Lower Basin Shortages. The same agreement led to the 18 percent cut in Arizona’s allotments last year — as well as cuts to Nevada and Mexico — after shortages were declared in Lake Mead.

Water levels in the two reservoirs are expected to fall and reach worse shortage levels in upcoming years, leading to more water allotment cuts, but the Drought Contingency Plan and current rules for operating the reservoirs expire in 2026.

Reclamation will also try to slow the declining water levels by minimizing evaporation and seepage at the reservoirs and their dams.

No cuts have to be made to California’s water allotments in 2023 because of the contingency plan, according to Reclamation.

Resources from Feds, sacrifices in Tucson

The Bureau of Reclamation will try to reverse the shortages and help the states with the cutbacks by using “additional resources” from the $1.2 trillion Bipartisan Infrastructure Law and the Inflation Reduction Act, which President Joe Biden signed on Tuesday, Touton said.

According to Reclamation, this includes $8.3 billion invested to water and drought challenges, water and power infrastructure and adapting existing projects to changes in hydrology.

The Inflation Reduction Act sets aside $4 billion in funding specifically for water management and conservation efforts, according to the bureau, in the Colorado River Basin and other areas experiencing similar levels of drought.

The city of Tucson set itself apart from Colorado River users after the City Council agreed they would be the first city to give up its Colorado River to save Lake Mead in May.

Tucson announced a joint effort with the Gila River Indian Community that month to give up their Lake Mead allotments together, but the city still has to negotiate with other Colorado River users in the state and region. City staff is looking into what Tucson can get in exchange for giving up its allotments and expects to start negotiating soon.

Because of Tucson’s geography, the city can rely on groundwater from its aquifer. For years, Tucson has been storing much of its annual supply of CAP water by recharging it into the local aquifer, to be tapped later.

'Partners in the West'

Despite the forced cuts, federal officials say the government is committed to "working together" with states and tribes in the basins and Mexico to respond to dropping water levels in the two reservoirs together.

Reclamation has been in talks with Colorado River users since June about the reductions needed to sustain Lake Mead, Touton said.

Conserving water in Lake Mead will rely on a “system of conservation and voluntary agreements,” according to BOR, but Toutan said that “although significant progress has been made” in this area, those agreements “are not complete.”

“Reclamation understands the difficult decisions the basin states must consider and appreciates and respects the way state leaders serve the needs of their citizens,” Touton said. “They have long been our partners in managing water in the West and will continue to be our partners.”

Bennito L. Kelty is’s IDEA reporter, focusing on Inclusion, Diversity, Equity and Access stories, and a Report for America corps member supported by readers like you.

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