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August 25th, 2022
Courtesy of the Wall Street Journal, a look at how the Colorado River’s dwindling supply of water will be doled out based on customers’ priority set forth in previously agreed-upon contracts:
Arizona farms are first in line to bear the brunt of the biggest restrictions put in place on the use of the Colorado River’s water after officials declared an unprecedented shortage last week.
Lake Mead reached its lowest water level since the 1930s in July, and low levels are projected to continue into 2023, prompting officials at the Bureau of Reclamation to drastically reduce Arizona’s consumption of the river’s water. Last year, the river’s already low levels resulted in Arizona getting 512,000 acre-feet less water in 2022. Even drier conditions this year led to a cut of 592,000 acre-feet in 2023, or 21% of its annually allocated Colorado River water. Nevada and Mexico are also subject to the restrictions, reducing their supply by 8% and 7%, respectively. California, the river’s largest user, isn’t subject to the restrictions.
The 2023 cut of 592,000 acre-feet of water is equivalent to about 300,000 Olympic-sized swimming pools of water, which are about 2 acre-feet each when 6 feet, 7 inches deep. If 300,000 pools were placed next to one another in a rectangle, they would stretch for about 145 square miles.
How the river’s water is doled out depends on customers’ priority set forth in previously agreed-upon contracts. Drinking water and much of the residential, commercial and Native American users rank among the top of the priority list and aren’t expected to be affected by the cuts.
Agricultural operations in central and southern Arizona, however, rank among the lowest priority for deliveries from the Colorado River and will be among the first whose supply gets cut.
Here is what it means for the state.
Arizona is allocated 2.85 million acre-feet of water from the Colorado River each year. About 40% of that is used by cities, farms and Native American tribes along the river. Their use is considered high priority and isn’t subject to the restrictions.The remainder is diverted from Lake Havasu to Phoenix, Tucson and surrounding areas via the Central Arizona Project’s, or CAP’s, canals.
On average, in a non-shortage year, CAP delivers 1.5 million acre-feet of water.
Agricultural users in CAP’s service area–mostly in Pinal County–rank among the lowest priority customers and aren’t expected to receive any Colorado River water in 2023. They also didn’t get any this year after last year’s cuts went into effect. These farms purchase their water from other sources.
The next lowest priority are so-called NIA regions, which include certain cities, industries and tribes not part of higher priority delivery groups. That covers a portion of Phoenix’s water, plus some private water providers, mines and power companies. About 97% of this water will be cut, up from 63% this year, according to Arizona State University.
Officials in Arizona objected to the amount of cuts that the federal government is demanding of them. “It is unacceptable for Arizona to continue to carry a disproportionate burden of reductions for the benefit of others who have not contributed,” said Tom Buschatzke, director of the Arizona Department of Water Resources, and Ted Cooke, general manager of the Central Arizona Project water agency.
After the agricultural sector, municipal customers used the most water—500,000 acre-feet of CAP water in 2020, or 18% of the allotment. Because much of the residential water used indoors is reclaimed and reused, reductions in water use for outdoor landscaping would provide the biggest benefits to conservation efforts, according to Arizona State University.
The Southwest is locked in its worst drought in 1,200 years, according to a University of California, Los Angeles-led study earlier this year.
Unusually strong monsoon rains this summer have helped replenish dry soils and reduce wildfire risk, but they added little to the reservoirs in part because so much water evaporates in the heat, water officials say. The reservoirs depend mostly on snowmelt runoff, which has sharply declined because of the warming climate, the officials said.
The 1,450-mile Colorado River fuels $1.4 trillion in annual economic activity in the basin states, according to a 2015 study by Arizona State University. If the Colorado River stays at historically low levels, the next level of reductions could begin to cut into municipalities’ and Native American lands’ water use.
