Nevada’s water managers are pleading their case to the Trump administration before it hands down a final Colorado River operating agreement that may see states fighting in the U.S. Supreme Court over their right to use the dwindling river.

In a letter dated Aug. 12 and released to the Las Vegas Review-Journal on Tuesday, state officials call out what they see as a flawed legal framework that could unfairly assign shortages to the Silver State, California and Arizona — its neighbors in the Lower Colorado River Basin. Clark County draws about 90 percent of its water from the Colorado River, though Nevada has the smallest share of any seven states that rely on it.

“Nevada has been the single most proactive state on the River in terms of planning for lower River flows and implementing common-sense water conservation to reduce use,” officials wrote. “Cuts of this magnitude would affect quality of life and potentially harm the health, human safety, and welfare of this community.”

Water managers said the document charts a path where the federal government could force Nevada to give up some 64 percent of its allocation of the river. Any cuts above 102,000 acre-feet would push the state past its total use after accounting for water recycling credits last year, which came in at 198,000 acre-feet.

It’s unclear exactly when the Bureau of Reclamation and Interior Department will finalize a plan, but Nevada’s letter is based on the agencies’ final environmental impact statement, which identified a preferred path forward that could mean significant cuts to the state’s meager share of the river over the next 10 years.

The plan does not include any mandatory cuts to the Upper Basin states of Colorado, Utah, Wyoming or New Mexico, though it describes 200,000 acre-feet of voluntary reductions.

An operating agreement would be reevaluated by state and federal officials every two years.

The comments align with previous statements from John Entsminger, the state’s Colorado River czar and general manager of the Southern Nevada Water Authority, and Nevada Gov. Joe Lombardo.

At a Colorado River summit last week, Entsminger told reporters he is still advocating for the state’s interests in ongoing conversations with the federal government and the other six states in the Colorado River Basin.

“We saw version A, and now we’re trying to land on version C or D that everyone can live with,” Entsminger said.

Both Arizona and the Colorado River Indian Tribes, a sovereign nation based south of Lake Havasu City, have also publicly raised issues with the proposed operating agreement.

The tribes own a significant share of some of the most high-priority water rights in the basin — some 720,000 acre-feet, more than double that of Southern Nevada. Much of that has gone unused due to the inefficiency of the Colorado River Indian Irrigation Project, managed by the federal Bureau of Indian Affairs, the tribe’s attorney wrote in its letter.

None of the 30 federally recognized tribes in the Colorado River Basin have had a meaningful seat at the table in negotiating rooms full of state and federal officials.

“We are deeply concerned that our trustee is showing how (tribes’) unused water is available for use by junior appropriators while also failing to acknowledge that our ability to use our decreed water rights is directly linked to the efficiency, or lack thereof, of the (irrigation project),” the tribes wrote.

Arizona is the state that stands to lose the most under the proposed operating regime.

The Central Arizona Project — the 336-mile system of tunnels, plants and pipelines that moves river water from the Colorado River downstream from Lake Havasu City, Arizona, to Phoenix and Tucson — could suffer deep cuts that would imperil the water supply of its biggest cities.

Arizona Department of Water Resources Director Tom Buschatzke laid out his state’s objections to the final environmental impact statement, emphasizing that his state still retains its rights under the 1922 Colorado River Compact.

“Arizona does not accept a framework that gives the federal government the discretion to select from a wide range of alternatives—including catastrophic cuts to the Lower Basin — every two years for the next decade,” he wrote.

All three letters, taken together, signal a growing appetite for a lawsuit at the U.S. Supreme Court, which is something a handful of states have publicly begun allocating money toward. Entsminger has said a court battle is far from ideal in ushering progress forward, but that Nevada’s water managers are ready to defend themselves if need be.

Some experts warn that a court case will cost taxpayers millions and does not provide anyone certainty.

Contact Alan Halaly at ahalaly@reviewjournal.com. Follow @AlanHalaly on X.