Water cuts on the Colorado River will harm many US states
Robert Glennon is Regents Professor and Morris K. Udall Professor of Law & Public Policy at the University of Arizona. This story was originally featured in The Conversation.
The U.S. government announced its first water scarcity statement for the Colorado River on August 16, 2021, triggering future cuts in the amount of water states can draw from the river. The Tier 1 Scarcity Statement followed the U.S. Bureau of Reclamation’s prediction that the water in Lake Mead – the U.S.’s largest reservoir on the Arizona-Nevada border – will sink below 1,075 feet above sea level and less than 40 . % of its capacity remains until the end of 2021.
The statement means that in January 2022, the agency will reduce water supplies to the states of Arizona and Nevada in the Lower Colorado River Basin, as well as Mexico, but not yet California.
Arizona will lose the most water: 512,000 acre-feet, nearly one-fifth of the total Colorado River allotment of 2.8 million acre-feet. Nevada loses 21,000 and Mexico 80,000. An acre foot is enough water to cover an acre of land, roughly the size of a soccer field, to a depth of one foot – about 326,000 gallons.
Central Arizona farmers are the big losers in this first round of cuts. The cities are protected because they enjoy Arizona’s top priority for water supplied by the Central Arizona Project, a 330-mile canal from the Colorado River. From my experience of analyzing Western water policy, I expect that this declaration will not stop growth in the affected states – but growth can no longer be uncontrolled. Increasing the water supply is no longer a viable option, so states must turn to demand.
The preservation remains the low hanging fruit. Reusing water – treating and reusing wastewater, including for drinking – is also feasible. A third possibility is to promote the redeployment of water from a lower to a higher-quality use through pricing and trade.
The Colorado River Basin flows into seven western states. The lower basin is more developed than the upper basin and uses more water. Map: USGS
Arizona is suffering the biggest cuts because it agreed in the 1960s that it would have the lowest priority among the Lower Basin states.
California will not cut back until the level in Lake Mead drops further. But that could happen as early as 2023. The water level is sinking partly because of the western drought, but also because of the shape of Lake Mead, which was created in 1936 by the damming of Boulder Canyon.
Like most western river canyons, Boulder Canyon is wide at the rim and narrow at its base, like a martini glass. As the water level decreases, each remaining foot in the lake holds less water.
Lake Mead feeds the Hoover Dam, one of the largest hydroelectric power stations in the country. The plant produces electricity by moving water through turbines. When Lake Mead is high, the Hoover Dam’s generating capacity is more than 2,000 megawatts, which produces enough electricity to power about 450,000 average households in Nevada, Arizona, and California.
But the plant lost 25% of its capacity as Lake Mead sank. If the water level drops below about 950 feet, the dam will be unable to generate electricity.
The states of the Colorado River Basin have formally negotiated who can use how much water from the Colorado River since they first colored the Colorado River Compact from Lake Mead in 1922. A number of subsequent agreements, including Mexico, increased the size of the cuts, and eventually empowered the Home Secretary to implement really draconian cuts.
Send water south
The states of the Upper Basin – Colorado, Wyoming, Utah, and New Mexico – will also suffer.
That’s because the Colorado River Compact requires the Bureau of Reclamation to release an average of 8.23 million acre-feet annually from Lake Powell, the country’s second largest reservoir, which stretches from southern Utah to northern Arizona.
The Bureau of Reclamation forecast in mid-July that the outflow into Lake Powell will be only 3.23 million acre-feet, or 30 percent of the average, by 2021. To make up for this shortage, the office will release more water from three reservoirs in the Upper Basin: Flaming Gorge in Utah, Blue Mesa in Colorado, and Navajo on the Colorado-New Mexico border.
These releases will harm farmers and ranchers who, due to lack of water, may be forced to produce less water-intensive crops or fewer animals. The states of the Upper Basin get much of their water from the snowpack, which has decreased in recent years as the west has warmed.
Do the math
The ultimate problem facing the Colorado River Basin states is simple. There are more water rights on paper than river water. And that’s before considering the effects of climate change and the evaporative losses from Lakes Mead and Powell.
The urgency of the Tier 1 Scarcity Declaration has led to wild proposals to import water from distant places. In May 2021, the Arizona legislature passed a bipartisan resolution calling on Congress to investigate a pipeline from the Mississippi River that would expand the Colorado River. Space doesn’t allow me to work out all of the barriers to this idea, but here’s a big one: the Rocky Mountains.
Similarly, the city of St. George, southwest Utah, has proposed building a 140-mile pipeline from Lake Powell to increase its supply. St. George has one of the highest water consumption and lowest water prices in the country.
The gospel of growth still motivates some cities. Buckeye, Arizona, on the west side of Phoenix, has a planning area of 642 square miles that is larger than Phoenix. The city has approved 27 housing developments that officials are planning to increase their population by 800,000 people by 2040. However, their water supply depends on unsustainable groundwater pumps.
Other churches have faced reality. In early 2021, Oakley, Utah, east of Salt Lake City, imposed a building oratorio on new homes, sending shivers down the spine of developers across the west.
Making farmers more efficient
The Tier 1 Declaration gives states and local communities an opportunity to remove barriers to water transfer. Market forces play an increasingly important role in water management in the West. Many new water demands arise from voluntary transfers between willing sellers and desperate buyers.
Water markets threaten rural communities because farmers cannot hope to compete with cities for a free water market. They don’t have to either. Water remains a public resource. I believe states need a process to ensure that transfers are in line with the public interest – a process that will protect the long-term viability of rural communities.
As the west enters an era of water redistribution, most of the water will come from farmers who use more than 70 percent of the area’s water. Cities, property developers and industry only need a tiny fraction of this for an indefinite period of time.
What if community and industrial interests set up a fund to help farmers install more efficient irrigation systems instead of simply flooding fields, a low-tech approach that wastes a lot of water? If farmers could cut their water consumption by 5 percent, that water would be available to cities and businesses. The farmers would continue to grow as much food as before, thus protecting the stability of the rural communities. This could be a win-win solution to the western water crisis.