01:08 Dangerously Low Lake Mead Levels Trigger Mandatory Water Cutbacks Mandatory water cutbacks for Arizona and Nevada will be put in place in 2020. Those states rely on the Colorado River and Lake Mead, which are almost tapped out.

At a Glance Lake Mead is expected to be below the level that triggers restrictions on the amount of water that can be taken from it.

This winter's snows have helped the Colorado River basin, but reservoirs are still far below normal levels.

Arizona and Nevada officials say the cuts are about the same amount they've been conserving already.

Arizona and Nevada are facing the first-ever mandatory cuts in the amount of water they can take from the Colorado River next year.

The two states are among seven that have agreed to drought contingency plans for the river system that serves about 40 million people and 6,300 square miles of farmland from Wyoming to Southern California.

The cuts are triggered by water levels expected in Lake Mead, a giant reservoir on the river at the Arizona-Nevada border. On Jan. 1, Lake Mead's level is projected to be 1,089.4 feet , the U.S. Bureau of Reclamation said late last week. That's just below the drought contingency plan threshold of 1,090 feet, and it means cuts for Arizona and Nevada.

For Arizona, the cut is about 7% of its annual allotment from the Colorado River, according to the Colorado Sun.

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That water would have been available for underground storage, banking and replenishment , Chuck Cullom, Colorado River programs manager for the Central Arizona Project, said in a blog post.

It's also about the same amount Arizona has given up voluntarily since 2015 as part of a conversation program, Cullom said.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/coloradoriver_0.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/coloradoriver_0.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/coloradoriver_0.jpg?v=ap&w=980&h=551 800w" > An aerial view of the Colorado River downstream of Lake Mead and upstream of Lake Mohave. The river system serves about 40 million people and 6,300 square miles of farmland from Wyoming to Southern California. (U.S. Bureau of Reclamation)

Nevada's 3% cut also is unlikely to cause much hardship. The state is already using about 25% less than its annual allotment this year, Bronson Mack, a spokesman for the Southern Nevada Water Authority, told the Associated Press.

"Conservation has reduced our water use significantly enough that we can make these contributions to the drought contingency plan without impacting future water," Mack said.

Arizona, Nevada and California signed the Lower Basin Drought Contingency Plan in May. Under it, California has agreed to contribute water at a lower trigger point if Lake Mead continues to fall.

Under a separate agreement, Mexico will give up 3% of its allotment.

Instead of relying on water level triggers for cuts, the Upper Basin states — New Mexico, Colorado, Wyoming and Utah — agreed to a demand management plan that includes reimbursing water users for voluntarily contributing water to Lake Powell, the other major reservoir on the Colorado River.

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Both Lake Mead and Lake Powell, have dropped dramatically because of a drought that has lingered for nearly 20 years.

The reservoirs have gotten a boost because of heavy snowfall across much of the Rocky Mountains this winter. The reservoirs are now at 55% of total capacity, up from 49% at the same time last year.

“While we appreciate this year’s above average snowpack, one good year doesn’t mean the drought is over. We must remain vigilant,” Bureau of Reclamation Commissioner Brenda Burman said in a statement .

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/HooverDam.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/HooverDam.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/HooverDam.jpg?v=ap&w=980&h=551 800w" > This photo shows the water level of the Colorado River, as seen from the Hoover Dam in Arizona, on March 26, 2019. (AP Photo/Richard Vogel)

Climate change means the river and its reservoirs may never return to full capacity. Unprecedented warming caused about half of the decrease in runoff from 2000-2014 in the Upper Colorado River Basin, according to the Arizona Republic. Higher temperatures have increased evaporation and reduced the flow of streams.

The river’s flow from 2000-2019 has decreased by about 17% from the 20th-century average, according to the Republic.

One study projects that without changes in precipitation, global warming will likely cause the river’s flow to drop by 35% or more by the end of the century.

“We can solve this climate problem. We just need to acknowledge it and get to work solving it,” said Brad Udall, a water and climate scientist at Colorado State University and co-author of the study. “Despite the fact that we had a great year here, as far as I’m concerned, it’s a little bit of a respite and we should enjoy it and thank Mother Nature, and get back to work on solving the problem.”