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Reclamation will manage the river under Tier 2a restrictions in 2023, requiring water cuts to Arizona, Nevada and Mexico but not California.

Todd Fitchette, Associate Editor

August 19, 2022

5 Min Read
Glen-Canyon-Dam-by-Bureau-of-Reclamation.JPG
Levels at Colorado River system reservoirs continue to fall. As this continues to expose the back side of dams at places like Glen Canyon Dam at Page, Arizona, water officials worry that minimum power pool and dead pool are real outcomes of the overuse of the Colorado River system amidst extended droughts. U.S. Bureau of Reclamation

The first-ever Tier 2a restriction on Lake Mead comes as some question why not operate the reservoir at its actual level, which falls within a more restrictive level.

The Tier 2a restriction mandates that Arizona, Nevada, and Mexico reduce their take on the river under the Drought Contingency Plan (DCP), which sets forth conservation measures ostensibly to prevent the reservoir from falling further. Under the plan, Arizona will be forced to cut its annual take by 592,000 acre-feet, or 21% of the state’s annual apportionment. Nevada will lose 8%, or 25,000 acre-feet of river access. Mexico will lose 7%, or 104,000 acre-feet of water it receives at Morelos Dam on the International border between Yuma, Arizona and Los Algodones, Mexico.

At an actual level of about 1,042 feet elevation in mid-August, Lake Mead is within the DCP’s definition of the more restrictive Tier 2b shortage. Under that restriction, California would be added to the list of river users forced to reduce their allotments. Because the reservoir will be operated under the Tier 2a restriction next year, California is not required to make cuts to its 4,4 million-acre-foot allocation.

Under Tier 2b, California is required to reduce its take by 200,000 acre-feet. Reclamation says the river annually yields an average, unregulated flow of 9.6 maf. At that level, California’s entitlement reflects about 45% of the entire river.

Related: There's a crisis on the Colorado River

In a game of assumptions, an earlier decision by the Bureau of Reclamation to hold back 480,000 acre-feet of water in Lake Powell to prevent it from falling to minimum power pool and having to shut down the hydroelectric facilities at Glen Canyon Dam, Reclamation will manage Lake Mead as if that water was delivered to the lower basin reservoir. That assumption is said to raise Mead to 1,047.61 feet at the end of 2022, which is within the Tier 2a threshold elevation of 1,045-1,050 feet above sea level.

The 480,000 acre-feet held back at Lake Powell comes after 500,000 acre-feet of water was moved from upper basin reservoirs in Utah, Wyoming, and New Mexico to Lake Powell’s to bolster its level. This move allowed Reclamation to promise that seven million acre-feet (maf) of water would flow through Glen Canyon Dam this year to the lower basin. This is down from the 7.48 maf earlier promised to move from the upper to lower basins.

Two months ago, the Department of Interior told Congress that the Colorado River users would need to cut 2-4 maf of water from their allocations to prevent the catastrophic failure of the system to deliver water and provide power to the West.

No agreement

The states were told then to meet and agree upon those cuts. If they could not agree, the Interior Department would step in and make that decision for the states.

In a strongly worded letter from Southern Nevada Water Authority General Manager John Entsminger to the Department of Interior and Bureau of Reclamation, Entsminger writes that the states failed to come to a “meaningful collective action to help forestall the looming crisis.”

Related: Can we curtail a Colorado River catastrophe?

While SNWA says it has “blazed the trail for urban water conservation both nationally and internationally,” the three states of Nevada, Arizona, and California are no closer to an agreement on preventing catastrophe within the Colorado River system than they were two months ago when Entsminger and Reclamation Commissioner Camille Calimlim-Touton testified to Congress that the system is on the brink of disaster because of declining water levels.

In mid-August the Department of Interior told the press that it would move forward with administrative decisions to prevent catastrophe within the system. Even so, the DOI and Bureau of Reclamation offered no firm numbers, other than to say Lake Mead would be managed at a Tier 2a shortage in calendar year 2023, despite its actual elevation.

Disaster looming

Colorado River conditions are in the driest 23-year period on record, according to the Bureau of Reclamation. Inflow into Lake Powell over the past five years is a little over half of its historical average. The reservoir is currently at 26% of capacity and within about 34 feet of “minimum power pool.” That is the level at which all hydroelectric operations at Glen Canyon Dam will cease. Engineers estimate that level at 3,490 feet elevation.

Lake Powell’s reported capacity is 25.1 maf. Both major reservoirs are projected to end the year with just 12.8 maf of water stored, or 25% of their combined capacity of over 50 maf.

Reclamation says it will operate Lake Powell in its lower elevation balancing tier for the foreseeable future as water levels will likely stay below 3,525 feet elevation until next summer, when runoff may bolster lake levels. In one scenario, hydroelectric operations at Glen Canyon Dam could cease next March and last for months or longer.

Related: California farmers depend on Colorado River water

Currently operating at just over half its designed capacity of 1,320 megawatts, the powerhouse at Glen Canyon Dam supplies power to the western United States. The loss of power will affect about 5 million retail customers in the West with higher prices.

Five-year projections at both reservoirs reveal a high likelihood that minimum power pool at Powell will continue through 2026. Lake Mead could fall to Tier 3 restrictions, necessitating further cuts to the lower basin states, including California. Under Tier 3, California will need to cut 350,000 acre-feet from its annual allocation.

About the Author(s)

Todd Fitchette

Associate Editor, Western Farm Press

Todd Fitchette, associate editor with Western Farm Press, spent much of his journalism career covering agriculture in California and the western United States. Aside from reporting about issues related to farm production, environmental regulations and legislative matters, he has extensive experience covering the dairy industry, western water issues and politics. His journalistic experience includes local daily and weekly newspapers, where he was recognized early in his career as an award-winning news photographer.

Fitchette is US Army veteran and a graduate of California State University, Chico. 

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