Arizona, California, and Nevada take less water from the struggling river.

The Colorado River flows into Lake Powell, on the Arizona-Utah border. Photo © J. Carl Ganter / Circle of Blue

By Brett Walton, Circle of Blue – June 14, 2024

As the Colorado River declines, one fundamental question hangs over the Southwest’s most important waterway: can its people and industries slash their water use, thus aligning their water demands with a shrinking supply?

The answer so far – with important caveats – is a clear but qualified ‘yes.’

The latest evidence: the three lower basin states of Arizona, California, and Nevada whittled their take from the river last year. Their combined consumption of just under 5.8 million acre-feet is the lowest annual total since 1983. That represents a decline of 13 percent compared to 2022, when Lake Mead, the basin’s largest reservoir hit a record low and a simmering crisis morphed into a full-blown emergency.

The 2023 water consumption numbers are detailed in a Bureau of Reclamation report published last month. Reclamation is the federal agency that oversees the basin.

The report comes as the seven basin states – including Colorado, New Mexico, Utah, and Wyoming in the upper basin – plus the basin’s tribes and the federal government are negotiating how the river should be managed in the future. The centerpiece of those talks is how to reduce demand.

Tom Buschatzke, director of the Arizona Department of Water Resources, told Circle of Blue that the drop in water consumption last year is an indicator that longer-term reductions are possible.

“I think it is a good precursor to getting used to living with less water as the river is expected to shrink,” Buschatzke said.

The report provides headline numbers, but it does not explain why demand fell. Water agencies in the basin point to at least three factors that contributed to the drop.

One is the availability of other water sources. California’s Colorado River consumption was just 3.7 million acre-feet last year, the lowest since 1949, according to Bill Hasencamp, the manager of Colorado River resources for the Metropolitan Water District of Southern California, a big regional wholesaler.

Met, as the district is known, is California’s largest municipal user of Colorado River water, and it reduced its take from the river by 40 percent last year. It was able to do so, in part, because of a robust snowpack in the Sierra Nevada mountains. That meant more water was available from the State Water Project, a canal system that exports water from Northern California to purveyors like Met hundreds of miles away.

“When you have a good year from the State Water Project, we can back off on our Colorado use,” Hasencamp explained. “So that has this ‘yo-yo effect’ for our demands on an annual basis. Sometimes more, sometimes less.”

For Met, the unreliability of these distant sources is a second factor, Hasencamp said. Met and other agencies are attempting to source more water locally, through reuse, desalination, or cleaning up groundwater basins contaminated with industrial chemicals. Met is in the design stage of the country’s largest water recycling facility, a roughly $8 billion project that will eventually provide water for 1.5 million people.

The move away from distant sources is already evident. Hasencamp said that Met’s imported water from Northern California and the Colorado River combined is down by more than half in the last two decades.

The third and most essential factor is conservation. Some reductions have occurred organically as outdated and wasteful appliances and toilets have been replaced with newer, more efficient models, as residents have swapped grass lawns with drought-tolerant landscaping, and as subdivisions have supplanted irrigated farmland, the largest water user in the basin.

Much of the recent conservation, however, has taken a different form. Some of the cuts were voluntary and compensated with cash payments. But most were mandated by rules put in place in 2007 and then expanded in 2019 under the basin’s drought contingency plan, or DCP. For instance, Arizona’s voluntary and mandatory conservation, compared with the volume of water it is legally entitled to consume from the river, was nearly 1 million acre-feet last year.

Conservation got an extra boost in 2022, when Congress passed the Inflation Reduction Act. That law provided $4 billion for drought response in the Colorado River and other western states. In effect, it enabled payments to farmers and cities to conserve water. Arizona, California, and Nevada worked out a deal last year that their water users would be paid not to use 2.3 million acre-feet over the next three years, through 2026.

Payments are an appealing carrot when forced to cut demand rapidly. What happens when that funding runs out? Current operating rules for the basin will expire at the end of 2026, and future conservation is not likely to be so generously compensated.

“Clearly the Inflation Reduction Act conservation money was a critical piece of achieving the additional conservation beyond our required DCP and 2007 guidelines shortages in Arizona,” Buschatzke said. “And there is a question about how or if you can maintain that post-2026.”

Cuts in water demand last year have stabilized – but not rescued – the basin’s reservoirs. Lake Powell is 38 percent full, and Lake Mead just 34 percent. There are still sharp disagreements between states, farmers, cities, and tribes about the distribution and severity of future water cuts. The conservation success in 2023 provided a rosy view of possibility. But take off the glasses, and the outlook is a bit fuzzier.