On Monday, U.S. officials are expected to declare the largest ever water shortage from a river serving 40 million West Americans. This will trigger cuts to Arizona farmers next year in the midst of a severe drought.

The Colorado River’s largest reservoir, Lake Mead, has seen water levels drop to new records. A white “bathtub” ring of minerals runs along its perimeter. It marks the spot where the high water mark was once. This highlights the water problems facing the region, which is now experiencing a growing population as well as a drought, which is made worse by the hotter and drier climate caused by climate change.

States, cities and farmers have diversified their water sources over time, which has helped to lessen the impact of the cuts. However, if current conditions continue to intensify or persist, further cuts will be felt more strongly in the coming years.

Lake Mead was created by the construction of Hoover Dam in 1930s. It is one of many man-made reservoirs that store water flowing from the Colorado River. This water supplies water for irrigation and drinking, as well as hydropower to Arizona and California.

But water levels at Lake Mead and Lake Powell, the river’s two largest reservoirs, have been falling for years and faster than experts predicted. The river’s flow from the Rocky Mountains (where it originates) has been reduced by scorching temperatures and less melting of snow in the spring.

“We are at a point where we’re dealing with how we can continue to thrive with less water and it’s very difficult,” stated Sarah Porter, director at the Kyl Center for Water Policy, Arizona State University.


The legal agreements between the seven Colorado River basin states and the federal government, Mexico, and other parties to the water storages at Lake Powell and Lake Mead determine how the water is divided up. These agreements establish how much water each party gets, when cuts will be triggered and in what order they must sacrifice some.

A 2019 drought contingency plan required Arizona, Nevada and California to agree to share their water in order to maintain Lake Mead’s water level. These voluntary measures were not enough to stop the declaration of shortage.


Lake Mead provides water for millions of people in Arizona and California, Nevada, and Mexico.

When water levels are predicted to fall below a threshold, such as 1,075 feet (328m) above sea level or 40% capacity, cuts for 2022 will be triggered. Lake Mead was at its lowest elevation since it was filled in 1930s with water. It was 1,068 feet (326 metres) earlier this summer.

Additional rounds of cuts will be initiated when levels fall to 1,045, 1,045 or 1,025 feet (320-318 and 312 meters).

Some industrial and city water users may be affected eventually.

Lake Powell’s levels are also falling, which could threaten the Glen Canyon Dam’s roughly 5 billion kilowatthours of electricity each year.

Colorado, New Mexico and Utah get their water from tributaries that flow into Lake Powell. Three reservoirs from those states have been drained to preserve the Glen Canyon Dam’s electric grid and maintain Lake Powell water levels.


Arizona, the U.S. state hardest affected, will lose 18% of its river share, or 512,000 acres of water. That’s around 8% of the state’s total water use.

One acre of water is sufficient to supply two households per year.

Nevada will lose approximately 7% of its allocation or 21,000 acre feet of water. It will not feel the water shortage due to conservation efforts and other sources.

California is exempt from immediate cuts due to its higher senior water rights than Arizona or Nevada.

Mexico will see an approximate 5% reduction, or 80,000 acres-feet.


Farmers in central Arizona, who are among the state’s largest producers of livestock, dairy, alfalfa, wheat and barley, will bear the brunt of the cuts. They will be the first to go without water in a drought because they are the ones who have water that is considered “extra”.

Farmers will have to abandon their land, as they did in the past due to drought. They will also need to rely more on groundwater and switch to water-efficient crops.

Water suppliers have prepared for the declaration of a shortage by diversifying their water supply and conserving it, such as by storing water underground basins. Water cuts make planning for the future more difficult.

Because of the cuts, the Central Arizona Project, which supplies water water to Arizona’s major cities will no longer be able to bank river water or replenish groundwater systems next year.

Chuck Cullom, Central Arizona Project, stated that “it’s an historic moment when drought and climate change have at our door.”

The first round of cuts is not applied to cities like Las Vegas, Phoenix, Tucson, or Native American tribes.


The dry spell that engulfed the West in 1999 and the increased demand for water have caused the reservoir’s water levels to fall since then. Experts predict that the reservoir will never again be full due to weather patterns that are expected to worsen.