As the Colorado River’s depleted reservoirs fall to new lows, the federal government is urging seven western states that depend on the river to find ways to drastically reduce water levels over the next two months.
The Department of the Interior is seeking emergency cuts to reduce the risk of the country’s two largest reservoirs, Lake Mead and Lake Powell, which are falling to dangerously low levels next year.
“We need to act now,” Tanya Trujillo, the interior ministry’s assistant secretary for water and science, said in a speech Thursday. “We need to take action in all states, in all regions and in all available ways.”
Trujillo’s virtual remarks at a conference at the University of Colorado Law School in Boulder underscore the urgent need to measure the region’s response to climate change stress, the precarious state of the river, and to prevent further erosion of reservoirs. Two days after he provided details about the federal government’s approach to the crisis, recovery commissioner Camille Kallimlim Touton announced that a major cut between 2 million and 4 million acre-feet was needed next year to prevent reservoirs from falling to “critical levels.”
For comparison, California, Arizona and Nevada used a total of 7 million acre-feet of Colorado River water last year.
State officials and water agency managers have not been able to determine how they can meet such a drastic reduction in water use. Finding ways to achieve the cutbacks will be the focus of talks between representatives of the seven states and the Biden administration in the coming weeks.
“The Colorado River Basin poses a greater risk than at any time in our modern history,” Trujillo said.
“There is still a lot of work to be done in the basin because the situation is deteriorating and a deep shortage is projected,” Trujillo said. “We need to do more than we have done before.”
After more than 22 years of droughts caused by warmer temperatures with climate change, Lake Mead and Lake Powell have fallen to their lowest levels. The two reservoirs are now about three-quarters empty, only 28 percent of full capacity.
The federal government’s latest projection shows no major change in water use, with reservoirs expected to decline over the next two years.
Lake Powell, on the Utah-Arizona border, has projected a fall of more than 30 feet by March, with the Glen Canyon dam holding a water level of about 16 feet from the point of power generation.
The country’s largest reservoir, Lake Mead, is now 1,045 feet above sea level. It is projected to fall more than 26 feet by July 2023. If Lake Mead falls, the level will eventually reach the danger zone of 895 feet, below which water will not flow from the Hoover Dam to supply California, Arizona and Mexico – a level known as the “Dead Pond”.
Trujillo said she was optimistic “we can get away with it.” But she also said it was a “very, very serious situation.”
The Colorado River originates in the Rocky Mountains and is an important resource for approximately 40 million people and farms from Wyoming to Southern California. Colorado has long been used extensively, diverting so much water to supply farms and cities that the river delta in Mexico dried up decades ago, leaving only small wetlands.
Colorado’s flow has dropped by almost 20% since 2000. Scientists estimate that high temperatures linked to global warming have reduced the flow of water by about half. And this hot-driven dryness, which scientists describe as “aridification,” is expected to worsen as temperatures rise.
The water level in Powell Lake is estimated to be only 59% of the average this year.
“We are facing the growing reality that water supply for agriculture, fisheries, ecosystems, industries and cities is no longer stable due to climate change,” Trujillo said.
Last year, the federal government announced for the first time a shortage in the Colorado River, which cut water deliveries to Arizona, Nevada and Mexico. In some parts of Arizona, farmers have left some fields dry and fallow, and are pumping more groundwater.
The cuts remain to limit supply to California, which uses the largest portion of Colorado River water. But that could soon change as federal authorities pressured all seven states to participate in diverting less water.
The Department of the Interior may impose cutbacks unilaterally, but Trujillo said the goal is to develop plans to work with states.
“We have the responsibility and the authority to take the necessary steps to protect the system,” Trujillo said. “We know we can be better served if we act collectively.”
Agriculture consumes about 80% of the water that flows from the river, much of it used to produce crops such as alfalfa, which is used to feed livestock and is exported in large quantities.
Because agriculture represents such a large share of water use, farming areas will bear a large part of the burden of water saving. Some of the earlier agreements included paying farmers who volunteered to temporarily leave part of their land dry.
On average, cities in Southern California, supplied by the Metropolitan Water District, typically receive a quarter of their water from the Colorado River. But this year, with the drought restricting other supplies from the state water project, the area is on track to receive about a third of the water from Colorado – a sum that will now be hampered by orders to conserve more.
Trujillo said federal, state and local authorities would “evaluate options to develop the additional protections we need.”
U.S. officials met with their Mexican counterparts this week to discuss ways to help.
Trujillo said she wanted the area to avoid a chaotic reaction.
“Our collective goal is to be able to quickly identify and implement strategies to stabilize and rebuild the system, so that we do not end up in constant crisis,” Trujillo said.
Last month, the Department of the Interior intervened to raise the water level in Powell Lake. The agency announced plans to release 500,000 acre-feet of water from the Fleming Gorge Reservoir upstream and an additional 480,000 acre-feet to Lake Powell by reducing the discharge from the Glen Canyon Dam.
Trujillo said the purpose was to preserve the hydroelectric capacity of the Glen Canyon Dam, to maintain the water supply to nearby communities, and to protect the dam’s infrastructure. He told state officials in a recent letter that if Lake Powell were to fall below its minimum level for power generation, the dam’s facilities would face “unprecedented operational reliability challenges.”
Below that level, water can still be routed through four 8-foot wide pipes, the dam’s river outlet works. But the water release capacity will be less. And officials aren’t sure how the dam’s infrastructure will fare at those levels.
Trujillo wrote that Glen Canyon Dam “was not intended to operate only through outlet works for extended periods and that operating at this low lake level would increase the risk to water distribution” And security.
Speaking at the conference, Trujillo said more water was being pumped into Lake Powell to protect the dam and keep it working reliably. Large water cuts are necessary for the same reason, she said, “to protect that basic infrastructure” so it will continue to operate in a “designed way.”
The river was divided between the states under the 1922 Colorado River Compact, which divided the water between the upper basins of the river (Colorado, Wyoming, Utah, and New Mexico) and the lower basins (Arizona, Nevada, and California). Separately, the 1944 treaty established how much water Mexico would receive.
The compact’s way of dividing the river between the upper basin and the lower basin states at 15 million acre-feet is now confronting the reality that the average annual flow of the river since 2000 is about 12.3 million acre-feet. The year is still short.
In the face of the current crisis, the representatives of the seven states are also preparing to make new rules to address the shortage after 2026, when the current rules expire.
The federal government will issue a notice this month as it begins to accept input into those post-2026 regulations. Trujillo said officials would consider the impact of climate change and the declining flow of the river.
There are 29 federally recognized tribes in the Colorado River Basin, and tribal leaders are pushing for inclusion so that the river can play a greater role in negotiations. Trujillo said officials are meeting with the tribes and will move forward with a more inclusive process to ensure that our tribal communities are more involved than ever before.
In his search for a solution, Trujillo said Secretary of the Interior Deb Holland was involved and “we have the attention and support of the White House.”
Trujillo has enough funds available to help under the $ 1.2-trillion infrastructure law, including $ 8.3 billion for the Bureau of Reclamation. He said it could be used to help local bodies develop water-saving programs to repair infrastructure, improve water efficiency and strengthen response to shortages.
Trujillo said federal officials do not have a “pre-baked” formula for the required water cuts.
“We’re going to be very creative and develop a large list of possible options,” she said. “We’re probably going to do things we’ve never done before. And we have to have the courage to move on.”