KVIG Informative

The compact that still decides how much Colorado River water reaches Las Vegas was built on bad math from the start — negotiators in 1922 measured the river during two of its wettest decades in five centuries, and the gap between that promise and the river’s real flow is the same gap Nevada is now fighting the federal government over.

Commissioners from seven states gathered in Santa Fe, New Mexico, and signed the Colorado River Compact on Nov. 24, 1922, according to the compact’s text, printed in full in Nevada’s 1923 session laws. J.G. Scrugham signed for Nevada, one of seven commissioners each state’s governor had appointed, the document states. Herbert Hoover, then U.S. secretary of commerce, took part in the negotiations as the representative the president had appointed, according to the same text.

The compact didn’t divide the river’s water among individual states. It split the water by basin. Article III apportioned 7.5 million acre-feet of water a year to the Upper Basin states and the same amount to the Lower Basin states, with the Lower Basin allowed to increase its use by another 1 million acre-feet a year, the compact states. Nevada, grouped with Arizona and California as a Lower Basin state, had no state-specific share yet.

That 7.5-million-acre-foot figure rested on a measurement error. The stream-flow data negotiators used to estimate the Colorado’s supply in 1922 came from two of the wettest decades the river had seen in 500 years, according to the National Park Service’s Lake Mead National Recreation Area, which cites Bureau of Reclamation records. Negotiators put the river’s average annual flow at 16.5 million acre-feet; tree-ring and paleoclimate research the park service cites now puts the long-term average closer to 12.5 million acre-feet.

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Nevada’s Legislature approved the compact within weeks. Lawmakers passed Assembly Joint Resolution No. 1, approving the compact, with the Nevada governor’s approval recorded Jan. 27, 1923, according to the 1923 Statutes of Nevada. By then, Scrugham — the same commissioner who had signed the compact on Nevada’s behalf two months earlier — had been sworn in as Nevada’s governor, having won election in November 1922, according to the National Governors Association.

The compact still didn’t say how much of the Lower Basin’s water belonged to Nevada specifically. That came in 1928, when Congress passed the Boulder Canyon Project Act. Nevada ended up with 300,000 acre-feet a year, the smallest share of the three Lower Basin states, according to Nevada Gov. Joe Lombardo’s office.

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The shortfall that 1922 measurement error created is no longer abstract. The U.S. Department of the Interior signed a new Record of Decision on Aug. 21, 2026, cutting Lower Basin deliveries by 1.25 million acre-feet a year through 2028, according to the department’s own announcement. Three days later, Nevada sued, telling a federal court the decision could cut its 300,000-acre-foot share by up to 213,556 acre-feet — more than 70% of the state’s already-smallest allocation on the river, according to the governor’s office. The seven commissioners who signed at Santa Fe in 1922 promised a river that was never really there. More than a century later, Nevada is the one in court over the difference.