The latest on the Colorado River and Lake Mead report

A general view of the Hoover Dam and Lake Mead, seen from the Arizona side of the dam, near Boulder City, Nevada, on July 19.

The federal government announced that the Colorado River will operate in a Tier 2 shortage condition for the first time starting in January as the West’s historic drought has taken a severe toll on Lake Mead.

What this means:

Those cuts are part of a system that Colorado River states have already agreed to in the case of an unprecedented water shortage.

But experts say those mandatory cuts are not enough to save the river.

In June, Bureau of Reclamation chief Camille Touton told the river’s stakeholders to come up with a plan to reduce up to 25% of their water usage. 

She gave them an August 15 deadline, but negotiations have been difficult and are not finished. Touton did not specify on Tuesday any new deadlines that might be set for states to come up with a plan for the drastic cuts.

“Today we’re starting the process and more information will follow as far as the actions we’ll take in that process,” Touton said on Tuesday. “I want to continue to push on the need for partnership in this space and the need for collaboration and finding a consensus solution. Not just for next year but for the future.”

Some of the river’s stakeholders are eager for the federal government to step in with a plan. John Entsminger, the general manager for the Southern Nevada Water Authority, told CNN that so far not enough of the stakeholders have put forth proposals that would get the basin to Touton’s target.

“There’s only so much water, and mother nature will figure this out at some point,” Entsminger said. “At some point, there’s just not water in the river channel.”

Biden signs the Inflation Reduction Act of 2022 into law during a ceremony in the State Dining Room of the White House in Washington, D.C., on Tuesday, August 16.

Congress’s recently passed climate bill contains $4 billion for drought relief funding which will essentially pay farmers, communities, tribes and businesses if they voluntarily cut their water usage. It pairs with an infrastructure bill passed last year that contained billions in climate resilience funding, including funds to help shore up deteriorating reservoirs. 

President Biden signed the sweeping bill this afternoon.

Perhaps even more important is the nearly $370 billion in the bill that will help rein in the climate crisis by cutting US greenhouse gas emissions using tax incentives for clean electricity and new programs to curb methane leaks and remove carbon from the air.  

“It’s going to take decades, but the bill will help stabilize the climate change impacts on the [Colorado] river,” Eric Kuhn, a southwestern water expert, recently told CNN.  

The bill is the largest climate investment in US history and is expected to cut US greenhouse gas emissions 40% by the end of the decade. 

Read more about the climate provisions in the bill here.

We should address the elephant in the room: There is actually less water in Lake Mead than what the US Bureau of Reclamation reported on Tuesday.

And, significantly, it was enough to prevent Southern California from having to take its first mandatory cut of Colorado River water.

So what’s happening?

Earlier this year, the bureau announced an emergency plan to keep Lake Powell from plummeting so low that Glen Canyon Dam wouldn’t be able to generate hydropower. It is releasing more water from upstream reservoirs, and it’s also withholding water in Lake Powell, rather than sending it downstream to Lake Mead and the Lower Colorado River Basin.

Lake Powell was supposed to release 7.48 million acre-feet of water to Lake Mead this year. Instead, it only released 7 million, leaving 480,000 in Powell.

Tuesday’s report took that into account. It lays out the numbers as if that water was delivered to Lake Mead.

Of course, all of this water is still in the same Colorado River system. Lake Powell and Lake Mead are like massive buckets that manage the rate of flow through the river and ensure everyone along it has the water they need.

Patti Aaron, a spokesperson for the bureau, previously explained it to CNN this way:

“If ‘actual elevation’ projected January 1 elevations are used in August, it would almost certainly put the Lower Basin in Tier 2 in 2023,” Aaron said. “To keep the water accounting ‘operationally neutral’ and not penalize the Lower Basin for leaving the water to benefit Lake Powell, we will run the models as if the [480,000 acre-feet] had been delivered to Lake Mead.”

Notably, running the math this way wasn’t enough to prevent the Lower Basin from falling into a Tier 2 shortage — but it was enough to prevent California from having to make cuts.

The real “physical elevation” of Lake Mead is expected to be around 1,041 feet come January. The projection after adding the withheld water was 1,047. 

And California doesn’t experience a Colorado River water cut until Mead is projected to drop to 1,045 feet.

Glen Canyon Dam is seen from the Glen Canyon National Recreation Area, where water levels of Lake Powell have declined dramatically, in Page, Arizona, on April 18.

The Department of the Interior said Tuesday it is prepared to take action again next year to limit the water releases from Lake Powell to prevent it from plunging below 3,525 feet above sea level by the end of 2023. Below that level, the Glen Canyon Dam, which forms the reservoir, cannot produce hydropower.

Lake Powell’s water level is expected to fall to reach 3,521 feet above sea level by the end of December.

The Bureau of Reclamation announced unprecedented, emergency steps earlier this year to help boost water levels at Lake Powell, beginning with releasing more water from upstream on the Colorado River, then holding back water in Lake Powell itself, instead of sending it downstream to Lake Mead.

At the end of July, Lake Powell had fallen to around 3,536 feet above sea level, which is 26% of its full capacity.

“There’s significant uncertainty in 2023 and two years out in 2024,” Dan Bunk, deputy chief of Boulder Canyon Operations Office, said at a Tuesday news conference. “While there’s the possibility of improved conditions at Lake Powell – with above-average inflow next year – it would take multiple years of above average inflow for Powell to recover, and the vast majority of hydrologic projections show that Lake Powell would remain at about the same level or continue to decline over the next two years.”

“We are particularly concerned about the projections … [that] show Lake Powell declining below elevation 3,490 as early as the middle of 2023.”

Glen Canyon Dam provides power for many states including Wyoming, Utah, Colorado, New Mexico, Arizona, Nevada, and Nebraska.

Additionally, in concert with its rapidly declining levels, a recent government report also showed that the amount of water Lake Powell could store is also shrinking as sediment fills the bottom of the reservoir.

Because of that, Powell had sustained an average annual loss in storage capacity of about 33,270 acre-feet of water, or 11 billion gallons, per year between 1963 — when Glen Canyon Dam was built — and 2018. That’s enough water to fill the Reflecting Pool on the National Mall about 1,600 times.

The Central Arizona Project, which funnels water from the Colorado River system, runs along the edge of a neighborhood in Maricopa County, Arizona, in August 2021.

Of the states impacted by next year’s mandatory water cuts, Arizona will face the largest — 592,000 acre-feet, or about 21% of the state’s yearly allotment of Colorado River water.

An acre-foot of water covers an acre one foot deep.

Meanwhile, California will have no cuts. This is because Arizona has junior Colorado River water rights, due to a decades-old compromise with California.

The Central Arizona Project, authorized by Congress in 1968, is a massive, 336-mile canal and pipeline system that funnels water from the Colorado River system across the Arizona desert to cities such as Phoenix and Tucson, as well as farms and towns in between. 

Prior the project’s completion in the 1990s, central Arizona relied heavily on groundwater pumping, which quickly sucked aquifers dry. Although the state was entitled to some of the water flowing in the Colorado River, it was only using about half of the allocation before CAP was completed. No channels or infrastructure at the time could deliver Colorado River water to cities in the middle of Arizona.  

California long opposed the project until Arizona made a key compromise to gain its support: In the event of a water shortage — which the lower Colorado River basin states are facing right now — California’s water deliveries would have priority over the needs of Arizona’s CAP water users.  

A worker irrigates a cotton field using a ditch that draws water from the Central Arizona Project at a farm in Marana, Arizona, in August 2021.

While Arizona will take the steepest cuts, the state does have some banked excess Colorado River water in underground aquifers in central and southern Arizona, which it has been recharging since 1997.

But “these supplies are finite and must be used carefully so that they can be used to assist cities and tribes in the years to come,” Evans said.

An aerial view of Lake Powell and the Glen Canyon Dam in Page, Arizona. According to a statement, the Bureau of Reclamation says it will evaluate whether the dam can be modified to "allow water to be pumped or released from below currently identified critical and dead pool elevations.”

Tanya Trujillo, the assistant secretary for water and science at the Bureau of Reclamation, said the agency is taking several immediate actions in both the upper and lower Colorado River basin to ensure the water is being used efficiently.

Shortly after the bureau announced the results of its annual forecast on the Colorado River and the country’s largest reservoir, Lake Mead, Trujillo said everyone has a responsibility to safeguard the water system. The report showed water levels dropping as the region suffers from a multi-year drought.

Federal investments and expanded resources now available through climate provisions in big bills like the Inflation Reduction Act, which President Biden is expected to sign Tuesday, are critical, Trujillo said.

Without investments now, she said the Colorado River will “face a future of uncertainty.”

Now, Trujillo said the bureau is “moving forward with several efforts at the same time.”

This means setting into motion short-term operational actions while also developing innovative strategies to help communities combat the conditions created by climate change in a more long-term way.

According to a statement, here are some of the things the Bureau of Reclamation says it will do:

The Upper Basin:

The Lower Basin:

The US Bureau of Reclamation will not yet act on a demand for Colorado River states and stakeholders to come up with a plan to cut up to 25% of their water usage — 2 to 4 million acre-feet per year, annually — to stabilize the river basin. That plan would have been in addition to the mandatory cuts announced on Tuesday.

Bureau chief Camille Touton made the demand for the plan at a Senate hearing in June and gave river stakeholders a deadline of Aug. 15. Touton said at the time that if states failed to come up with a plan, the federal government would do it for them.

Instead, administration officials said they are beginning that process.

Touton said at a news conference Tuesday that her agency is “starting the process,” but she did not specify any new deadlines that might be set for states to come up with a plan for the drastic cuts.

Administration officials indicated they did not want to impede state negotiations and wanted to focus on using federal money from climate and infrastructure bills to make improvements to Western water infrastructure.

US Deputy Secretary of the Interior Tommy Beaudreau called the current situation with state negotiations “a complex environment.”

Tuesday’s mandatory cuts, as a result of the Bureau of Reclamation’s August study for Lake Mead, will lead to a reduction of 721,000 acre-feet of river water usage.

An acre-foot is the amount of water that would fill one acre a foot deep — roughly 326,000 gallons.

As the Colorado River Basin is experiencing its driest 23-year period on record, its total systems storage is at 37% full, down from 46% last year.

Lake Powell’s current elevation is at 3,534 feet, or 26% of capacity, according to Chris Cutler, the manager for the Water and Power Services Division at the Bureau of Reclamation. 

During a presentation, he showed that water storage levels of both Lake Powell and Lake Mead has fluctuated over 50 years.

But as a result of below-normal runoff this year, Lake Powell is projected to drop to 23% of storage capacity by the end of 2022.

A screenshot of the Bureau of Reclamation's Colorado River presentation shows water storage capacity at Lake Mead and Lake Powell.

People walk along an area of Lake Powell that used to be underwater in March 2022.

The drought in the Colorado River basin is reaching “a tipping point,” Camille Calimlim Touton, the Bureau of Reclamation Commissioner, said. Her remarks come as the bureau announced its forecast for the water system in the West at a time when the region is experiencing a multi-year megadrought made worse by the climate crisis.

Touton said the Colorado River basin is in its 23rd year of a “historic drought.” This year’s forecast prompted the bureau to declare a Tier 2 water shortage on the Colorado River — forcing several Southwest states to make mandatory water cuts for the second year in a row.

The commissioner said Lake Powell and Lake Mead — the country’s two largest reservoirs — are also at “historically low levels.”

By taking conservation actions, like water cuts, she said the bureau needs to ensure communities, tribal nations and the environment are sustained, not just next year but for the future

“Protecting the system means protecting the people of the American West,” she said.

A formerly sunken boat sits on the dried lake bed of Lake Mead in May.

The federal government announced Tuesday the Colorado River will operate in a Tier 2 shortage condition for the first time starting in January as the West’s historic drought has taken a severe toll on Lake Mead.

According to a new projection from the Department of the Interior, Lake Mead’s water level will be below 1,050 feet above sea level come January — the threshold required to declare a Tier 2 shortage starting in 2023.

Lake Mead’s level has been around 1,040 feet this summer, just 27% of its full capacity.

The Tier 2 shortage means Arizona, Nevada and Mexico will have to further reduce their Colorado River use beginning in January. California will not yet have cuts made to the water it receives from the Colorado River. (The threshold for California’s first cut is 1,045 feet in January.)

Of the impacted states, Arizona will face the largest cuts — 592,000 acre-feet — or about 21% of the state’s yearly allotment of river water.

“Every sector in every state has a responsibility to ensure that water is used with maximum efficiency. In order to avoid a catastrophic collapse of the Colorado River System and a future of uncertainty and conflict, water use in the Basin must be reduced,” Interior’s assistant secretary for water and science Tanya Trujillo said in a statement.

Interior’s projections show that by January of next year, Lake Mead’s water surface elevations will be at 1,047.61 feet. Meanwhile, Lake Powell’s water surface elevation will be at 3,521.84 feet – 32 feet above minimum power pool, or the amount needed to generate electricity from hydroelectric operations.

Separately, US Bureau of Reclamation Commissioner Camille Touton and other federal water officials said they are prepared to take additional administrative actions needed to protect the Colorado River, Lake Powell and Lake Mead from falling to “critically low levels.”

Earlier this summer, Touton set a deadline of mid-August for the seven Colorado River states to come up with a plan to cut as much as 25% of their river water usage. It became apparent early this week that those negotiations have stalled, which led some lawmakers and state water officials to call on the federal government to take aggressive action on their own.

Interior has not yet outlined next steps in Touton’s demand for the states’ plan.

Swimming pools sit in the backyards of homes in a residential neighborhood in Henderson, Nevada, in July 2021.

At a June Senate hearing, Reclamation Commissioner Camille Touton laid out a stark warning. In order to stabilize the Colorado River basin, states and water districts would have to come up with a plan to cut 2 to 4 million acre-feet of water usage per year by mid-August, or the federal government would step in and devise a plan for them. 

It’s a massive amount — the high end of the target is about 25% less water than states currently receive. And the low end of the target represents the vast majority of Arizona’s yearly allotment of Colorado River water.  

Touton made clear in June the federal government would act if the states didn’t. 

Reclamation has not often stepped in and taken control of water management plans from the states, but it has the authority to do so in the lower Colorado River basin — which includes Arizona, southern Nevada and southern California. Experts told CNN the threat of federal action is something states will respond to. 

“We kind of need the federal government to make some threats to spur action,” John Fleck, a West water expert and professor at University of New Mexico, told CNN earlier this year. “Progress seems to happen when the federal government comes in and says to states, you need to do this or we’re going to do something you don’t like.”  

A dry irrigation canal runs along the edge of a field at a farm in Casa Grande, Arizona, in August 2021.

An extraordinary drought in the West is drying up the Colorado River and draining the nation’s largest reservoirs – Lake Mead and Lake Powell. And amid the overuse of the river and the aridification of the region, the federal government is preparing to make mandatory water cuts and asking states to devise a plan to save the river basin.

Two major announcements could come Tuesday:

The growing concern is that the mandatory cuts aren’t enough to save the river in the face of a historic, climate change-driven drought.

At a June Senate hearing, Bureau of Reclamation chief Camille Touton laid out a stark warning: In order to stabilize the Colorado River Basin, states and water districts must come up with a plan to cut 2 to 4 million acre-feet of water usage by next year. (An acre-foot is the amount of water that would fill one acre a foot deep — roughly 326,000 gallons.)

She also made clear that if the states cannot come up with a plan, the federal government will act.

Keep reading here.

The Hoover Dam houses turbines that are powered by the force of water to generate electricity.

Amid an intense drought stretching for more than two decades, the Colorado River basin’s water supply is rapidly declining, and worrisome projections continue to show Lake Mead plummeting toward “dead pool” status — when a reservoir isn’t high enough to release water downstream through a dam. 

Before reaching dead pool levels however, a lake would first reach “minimum pool status,” which is the point when a dam can no longer produce hydroelectricity due to a lack of water in the reservoir. 

Lake Mead’s water level is currently around 1,040 feet above sea level — around 145 feet away from reaching dead pool status, which is at 895 feet of elevation. Remember, water levels are measured by elevation relative to sea level, not by actual water depth in the lake.

The Hoover Dam houses turbines that are powered by the force of water to generate electricity. But they will struggle to generate hydropower as the water level falls toward dead pool level. Halting hydroelectricity production at the Hoover Dam would impact 1.3 million people across Arizona, Nevada and California. 

Neighboring Lake Powell is also dangerously close to minimum pool levels. As of Aug. 9, the lake was at 3,534 feet of elevation, just 44 feet away from ceasing electricity production at the Glen Canyon Dam. Dead pool at Lake Powell comes in at 120 feet lower, when the elevation falls to 3,370 ft.  

Around 70% of the West is in drought conditions as of last Thursday, according to the US Drought Monitor. Nearly 300,000 square miles of that — an area larger than any single state in the continental US — is considered in “extreme” or “exceptional” drought, the most intense categories.

These designations indicate areas of major crop loss, shortage of water in reservoirs, streams and wells requiring restrictions and eventually creating water emergencies, per the Drought Monitor’s website. 

Yet as dire as the situation is, last week’s report was an improvement. A year ago at this time, 90% of the West was in drought and twice as much of the area was mired in the worst two categories, compared to now.  

Back-to-back active Southwest monsoon seasons — which run from June 15 through September — have eased drought conditions over much of the desert Southwest including New Mexico, Arizona and Colorado.  

But it will take a lot more than that to erase the West’s historic drought, which has been entrenched for more than 20 years. Not every year since 2000 was drier-than-average, but the water debt in the soil and reservoirs has been accumulating and there has been at least some portion of the West with drought present in every weekly Drought Monitor update since early 2000.  

Scientists have noted that the current megadrought is the worst that Western North America has seen in 1,200 years. The West is no stranger to significant dry spells and droughts, but the human-caused climate crisis has supercharged the current one, making it 72% worse than it would have been without global warming. 

The turbine room is part of the system to generate hydroelectricity at the Hoover Dam.

Lake Powell and Lake Mead are at historically low levels and risk falling to “dead pool” status, which would mean there isn’t enough water to generate hydroelectricity for the tens of millions of people that rely on it, according to United Nations Environment Programme. 

Water cuts are necessary, the UN reports, to maintain adequate supply in reservoirs and continue hydroelectric production.  

But that still may not be enough, according to experts, who say climate change is the heart of the issue. 

Lis Mullin Bernhardt, an ecosystems expert at UNEP, says “we’re no longer speaking of a drought,” as the Colorado River basin is experiencing a “new very dry normal.” 

The West’s booming population has led to a spike in water demand and enhanced the impact of the climate crisis. Areas with more frequent drought will have to rely on groundwater — water that pools below ground and can only be reached by digging wells — which will continue to deplete with a lack of rainfall.  

“We are talking about a 20-year period of drought-like conditions with an ever-increasing demand on water,” Bernhardt said. “These conditions are alarming, and particularly in the Lake Powell and Lake Mead region, it is the perfect storm.” 

The reservoirs provide hydroelectric power and water for Nevada, New Mexico, Arizona, California, Wyoming, and Colorado, as well as part of Mexico.  

Rafters float down the Colorado River in Bond, Colorado, on July 2.

The Colorado River and its tributaries flow through seven states – Wyoming, Utah, Colorado, New Mexico, Nevada, California and Arizona – and Mexico. And that system supplies water and hydropower to 40 million people and irrigates more than 5 million acres of farmland.  

Las Vegas relies on the Colorado River for 90% of its water supply, Tucson for 82% and San Diego for around 66%. Large portions of the water consumed in Los Angeles, Phoenix and Denver also come from the river, and water experts say these thriving metropolises would not have been possible without its critical supply. 

But the system is now under threat. Plagued with overuse and a changing climate, the Colorado River’s two main reservoirs — Lake Mead, the largest in the country, and Lake Powell — have drained at an alarming rate. 

The underlying issue goes back nearly 100 years ago to the signing of the Colorado River Compact, a water-sharing agreement that determines how the river’s supply is divvied up and allocated across the basin states. States allocated the river’s water during a time of abnormally high precipitation — making it seem like the water would always be plentiful.  

US Bureau of Reclamation data shows that over the last two decades, the river’s flow has been 25% less than what states originally assumed in their pact. And studies show it could drop another 35-50% by 2200. 

“They thought there was a lot more water in the river than there actually was, so the river has actually always been overallocated,” Kristen Averyst, senior climate advisor for Nevada Gov. Steve Sisolak, told CNN. “Now we’re in a situation where climate change is really loading the dice.” 

The Colorado River’s water was divvied up a century ago. The seven states it flows through – Wyoming, Utah, Colorado, Nevada, California, Arizona and New Mexico – agreed to a pact that gave half of the river’s water to the Upper Basin states and half to the Lower Basin.  

There was one major problem: Having been written at a time when precipitation was higher than normal, that agreement overestimated how much water flows through the Colorado River. It also did not account for the West’s hotter and drier future in the face of the climate crisis. 

“We went [almost] 100 years without water shortages. It very well may be that we’ll never have a full allocation again,” Hasencamp added. “This is permanent shortages and so the way we look at water in the West has got to change. Water will never be the same in the West.” 

As the West faced more intense droughts, states agreed in 2007 to a shortage system that would lead to mandatory water cuts. Those cuts are tied to the water level in Lake Mead – a reservoir on the Lower Colorado River, and the country’s largest. 

The federal government announced the first of those unprecedented cuts in August 2021 when a Tier 1 shortage was declared. A Tier 2 shortage – and a fresh round of cuts – could be announced Tuesday. 

A formerly sunken boat sits on the dry lake bed of Lake Mead in June.

The water level in Lake Mead — the nation’s largest reservoir — dropped below 1,050 feet elevation for the first time in May, a critical milestone that signals more stringent water cuts are around the corner for the Southwest.

As the level drops, formerly sunken boats and even human remains are emerging in the mud, and other vehicles are getting newly stuck.

At least four sets of bodies were found earlier this year — one of which was found in a corroding barrel with a gunshot wound — could have been submerged in the lake’s depths decades ago.

One possible scenario for some of the remains is that they belong to people who previously drowned at the lake when water levels were high, a National Parks Service spokesperson told CNN. Recovery divers are limited on how deep they can go, so some drowning victims’ remains do not get recovered, they said.

The dropping water level has exposed a WW II-era landing craft, wrecked boats and the lake’s original 1971 water intake valve, and officials expect more surprises may be in store.

Keep reading about discoveries in Lake Mead here.

CNN’s Michelle Watson, Rachel Ramirez, Jenn Selva, Gregory Ramos and Stephanie Elam contributed to this report.

A dead fish lies on the dry lake bed of Lake Mead in May.

The UN’s Intergovernmental Panel on Climate Change has a clear message: The human-caused climate crisis is worsening extreme weather around the globe.

Unless greenhouse gas emissions are slashed — and fast — the report’s authors say it’s going to get worse. With significant advances in computing power, scientists are more confident than ever in attributing extreme weather to climate change.

A warmer planet is contributing to increased drought in the US, most direly in the West where the critical Colorado River and Lake Mead are drying up — two sources that supply water to millions of people.

Here’s how it works: The water begins its journey high in the Rocky Mountains of Colorado, Utah and Wyoming, where it first falls as snow. Snowpack reflects much of the sun’s energy back into space. But as the snow melts earlier and leaves behind exposed soil, more heat from the sun is absorbed by the ground, according to Chris Milly, a hydrologist with the US Geological Survey.

As winter fades and the snowpack melts, water drains into the mountain streams and tributaries that feed the Colorado River. The river’s vast drainage area is divided into two regions: the Upper and Lower Basin. Around 90% of the river’s flow originates in the Upper Basin.

After flowing down from the Upper Basin, the river snakes its way across the Southwest, eventually reaching Lake Mead near Las Vegas. From there, a system of dams, canals and pipelines channel it into the irrigation ditches that water farmland.

But, dry soils and thirsty plants also contribute to the problem. When soils are parched by high temperatures in the summer and fall months, it can lead to runoff reductions that persist even a year later, according to Brad Udall, a climate scientist at Colorado State University. Higher temperatures also mean that the atmosphere is “thirstier” and capable of holding more water. This increases evaporative losses from soils and water bodies.

Combating climate change: Several lawmakers who represent Western states asked leadership at the beginning of August to add more money in drought mitigation funding to Democrats’ larger tax and climate bill.

A Democratic source familiar with the negotiations told CNN that the drought programs would be managed by the US Bureau of Reclamation — the federal agency that oversees the Colorado River. 

The focus, the source said, would be to ease the impact of the drought on farmers and cities in the West.

A worker moves irrigation tubes on a farm in Pinal County, Arizona.

The Colorado River irrigates crops, powers electric grids and provides drinking water to 40 million people. But as its supply dwindles, a crisis looms.

The drying of the river and Lake Mead could force farmers to cut back even further on water usage, something experts worry could have larger affects on the economy.

States that rely on water from the lower Colorado River were already subject to the cuts that accompany a Tier 1 shortage beginning in January 2022, which have mainly impacted agricultural water use. But this year did not bring much-needed precipitation to the river basin — which could move the area into a Tier 2 shortage, following the release of the latest forecast from the US Bureau of Reclamation. This would mean further decreasing the amount of water Arizona, Nevada and Mexico, and possibly parts of California, can use from the river.

Scientists and water policy experts say that the science is clear: The Colorado River’s supply will likely shrink further as the planet warms. Given what we know, many say we will have to use even less water in the future.

Why it matters: Water cuts in the Lower Basin of the Colorado River and Mexico are tied to water levels in Lake Mead. In Arizona, the water cuts will have the greatest impact on lower-priority water users, like farmers in rural counties.

Arizona farmers like Dan Thelander have known for years that their supply of Colorado River water would eventually be phased out. They just didn’t expect it to happen so soon. Many farms in Arizona, like Thelander’s, specialize in growing alfalfa, corn and other crops to feed the thousands of dairy cattle on local farms.

Consumers in Phoenix likely won’t notice a difference when the water cuts kick in, said George Frisvold, a professor at the University of Arizona and a co-author of the 2018 study. But in the local farming economy, he expects there will be significant pain when the cutbacks take effect.

The same 2018 University of Arizona study found that under a scenario where farms in the area lose all of the Colorado River water allocated to them, it could cost the county between $31.7 and $35 million and as many as 480 jobs.

“You’ll have these ripple effects through the economy, and jobs go away,” Frisvold says. “In smaller, rural areas in Pinal County, it’s going to be more noticeable.”

There is also concern from some in the state about the farmers’ return to heavy groundwater pumping.

The Central Arizona Project — a massive, 336-mile canal and pipeline system that carries Colorado River water across the desert to Phoenix, Tucson and farms and towns in between — was authorized by Congress in 1968.

Before the CAP began delivering water to Pinal County’s farms in the late 1980s, farms here were totally reliant on groundwater to irrigate their crops. But pumping was depleting the aquifers faster than they could be replenished, causing huge fissures to form across the county as the ground sank.

Read more about economic impact of climate change.