‘Law of the river’ is the battleground in Colorado River crisis

It’s a nearly 100-year crisis: Seven states — all of which depend on a single mighty river for their vital water source — failed to reach an agreement this week on how best to reduce their consumption of supplies from the rapidly shrinking Colorado River.

At the heart of the feud is the “law of the river,” a collection of agreements, court decisions, treaties, and ordinances governing the use of the river, dating back to 1922, when the Colorado River Compact first divided rivers among states.

But while California is the strongest advocate for strict adherence to this system of water allocation, the other states say it makes little sense if the river’s largest reservoir, Lake Mead, continues to sink toward the “dead pond,” effectively cutting off the Southwest from his water lifeline. The law of the river, they say, stands in the way of a solution.

“We can argue about whether interpretations of the Law of the River match physical reality,” said Tom Buschatzke, director of the Arizona Department of Water Resources. “But if you argue these issues in a courtroom and something isn’t done, the Colorado River system will collapse.”

As drought, climate change, and chronic overuse weaken the Colorado River, the federal government has asked states to collectively reduce its use by 2 million to 4 million acre-feet.

California’s water districts have legal rights to most of the river, which not only provides drinking water for millions of Southern Californians, but also helps sustain the nation through agricultural irrigation. The other states — Arizona, Colorado, Nevada, New Mexico, Utah and Wyoming — say it’s unreasonable to let large population centers lower in the pecking order, like Phoenix and Tucson, get thirsty.

California’s legal position is based on several factors, said James Salzman, professor of environmental law at UCLA and UC Santa Barbara. First, the authors of the original Colorado Compact made the “fatal decision” to apportion water for the lower river basin states of California, Arizona, and Nevada in absolute amounts rather than percentages.

That means the upper basin states are required to deliver 7.5 million acre-feet per year to the lower states no matter what, which “turned out to be tragically bad design,” Salzman said.

Additionally, prior to the Colorado River Compact, California’s massive Imperial Irrigation District established senior rights to the water — meaning it has priority rights to deliver most of the river’s water to Imperial Valley farmland.

In contrast, Arizona agreed to junior rights on the river in 1968 in exchange for construction of the Central Arizona Project, the system that carries river water across the state.

In other words, by the law of the river, states like Arizona should be cut off from California if there isn’t enough water.

That has led to two very different proposals from states this week.

The California proposal includes an earlier commitment by Southern California water authorities to reduce water use by 400,000 acre-feet per year through 2026, a reduction of about 9%. The proposal also envisages further phased cuts in Arizona, California and Nevada as Lake Mead continues to decline.

The proposal put forward by the six states sees reductions from Arizona, California and Nevada that go beyond what those states have already agreed to. This results in particularly large reductions for California.

Rhett Larson, a professor of water law at Arizona State University, said California would emerge as a “clear winner” if the river’s law were interpreted as it is currently written.

“I’m an Arizonan, so I’m pretty biased in favor of Arizona,” he said. “But I’m also a lawyer, which means I’m pretty biased towards the law. And the law says California’s proposal is fundamentally correct — legally. It may not be practically or morally correct, but it is legally correct.”

Legislative texts include the 2019 Drought Emergency Plan, under which California, Arizona and Nevada agreed on a 2026 schedule to reduce Lake Mead.

Mexico has committed to participating in reductions under a separate agreement, and some indigenous tribes have also agreed to conserve water to increase reservoir levels.

But in recent years, these reductions have not been nearly enough and water levels in the reservoirs have continued to drop.

The 2019 agreement provides for cuts up to a point. If Lake Mead’s level reaches 1,025 feet — 22 feet below its current level — and continues to fall, existing rules about what should happen fall under the law of the river, Larson said.

But he also noted that the Central Arizona Project provides about 40% of the water supply for cities in central Arizona. He said it would be “devastating” for the Arizona project to make most of the cuts before California had to make significant cuts.

While the six-state proposal is not sufficient on its own, it “offers a better start and solves more problems and avoids more problems than California’s proposal,” he said.

For its part, California’s Colorado River Board said its plan “makes constructive efforts to uphold the law of the river while making significant efforts to protect the Colorado River system with voluntary reductions that go well beyond California’s legal obligations.”

“The 40 million people, nearly 6,000,000 acres of agriculture and 30 Native American tribes that depend on the Colorado River demands that we be successful in this effort,” the board wrote in its proposal.

Adel Hagekhalil, general manager of Southern California’s Metropolitan Water District, said all states agreed reductions were needed, but that “the priority system is part of the law.”

He noted that California has been working with the other states to adapt and adapt to changing conditions, including returning water to Lake Mead. Southern California has also made major water conservation efforts, imposing strict water-use restrictions and investing in alternative sources of supply.

“But we can’t sidestep a history of agreements that supported the livelihoods of California’s people, business and the economy that have been recognized in court and in history and say, ‘Let’s forget that,'” Hagekhalil said.

These court cases included Arizona vs. California, a 1963 Supreme Court case that ruled that of the first 7.5 million acres of river water, 4.4 million acres went to California, 2.8 million to Arizona, and 300,000 to go to nevada.

“It’s a long, complicated issue, but actually it’s about water rights,” Hagekhalil said, adding that “we all understand that we have to reduce.”

“Let’s assess the environmental impact of these cuts and take the time to negotiate who will make the cuts,” he said.

Still, some officials, including Buschatzke, criticized the California proposal as “extremely Law-of-the-River-centric.”

“I understand possible legal arguments. But the six-state proposal recognizes the physical reality of what is actually happening. …And California doesn’t,” he said.

UCLA’s Salzman said the likely outcome of the impasse is federal intervention, followed by litigation.

He couldn’t think of a similar case to serve as a precedent for the current standoff, but feared states would be running out of time as the river got drier and lower.

“You’re basically leaving the law of the river because the law of the river isn’t clear on how to reduce 2 million acre feet,” Salzman said. “On the other hand, the law of the river is why we’re in this mess in the first place.”