KVIG Informative

Nevada’s Office of the State Engineer designated the Las Vegas Valley an underground artesian water basin on Jan. 10, 1941, giving the state its first legal hold on water most Southern Nevadans never saw flowing beneath their feet. Eighty-five years and one uncertain new federal Colorado River framework later, that same basin — closed to major new groundwater rights since 1992 — is one of the only levers Nevada has left to answer a river it doesn’t fully control.

State Engineer Alfred Merritt Smith issued Order No. 175 on Jan. 10, 1941, designating the Las Vegas Valley an underground artesian water basin under Nevada’s Underground Water Act, which the Legislature had passed two years earlier, according to a hydrographic basin report published by the Nevada State Library and Archives. Smith held the State Engineer’s office from May 29, 1935, to June 5, 1951, according to the Nevada Water Resources Association’s own list of the state’s engineers. The basin he designated is now catalogued by the state as Hydrographic Basin 13-212.

Smith and his successors returned to the basin repeatedly over the next quarter-century, according to the same state archives report. Order No. 182 extended the designated area on Feb. 29, 1944, and Order No. 189 extended it again on Nov. 22, 1946. Order No. 196, issued Dec. 1, 1949, closed part of the basin to new irrigation rights and set a curtailment and preferred-use policy for the rights already on the books. Orders No. 249 and No. 275 followed on Apr. 18, 1961, and May 25, 1964.

The pumping behind those orders was already reshaping the valley floor. Land subsidence first appeared in Las Vegas Valley between 1915 and 1935, according to a U.S. Geological Survey report on the phenomenon. The deepest of several subsidence bowls beneath the valley had sunk more than 1.7 meters, or about 5.6 feet, by 2000, with other areas down more than 0.6 meters, or about 2 feet, the same USGS report found. Total subsidence across the valley reached as much as 6 feet since the 1930s, cracking the ground with fissures capable of damaging buildings, according to the Nevada Bureau of Mines and Geology at the University of Nevada, Reno.

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State engineers tightened the basin further as the subsidence data accumulated. Order No. 833, issued Dec. 27, 1983, amended the basin’s designation and imposed a non-preferred-use classification on much of its remaining capacity, according to the state archives report. Order No. 1054, a notice of curtailment issued Apr. 15, 1992, barred new permit applications filed after March 23, 1992 — closing the basin to major new groundwater rights, a restriction the Southern Nevada Water Authority’s Las Vegas Valley Groundwater Management Program still enforces today.

Subsidence rates slowed after the 1990s as water levels stabilized and, in places, rose, aided by artificial groundwater recharge programs run by local water agencies, according to the USGS report. The Nevada Bureau of Mines and Geology still tracks the valley’s remaining subsidence risk using GPS measurements and satellite radar, watching for renewed fissuring as the basin absorbs whatever new demand Nevada sends its way.

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That demand is rising again as Nevada’s other water source enters a less certain decade. The Department of the Interior issued a Record of Decision this year adopting a Decision Framework for Colorado River Guidelines governing coordinated operations of Lake Powell and Lake Mead from 2027 through 2036, based on a Final Environmental Impact Statement the Bureau of Reclamation released July 31, 2026. The seven Colorado River basin states could not reach consensus on longer-term operations after 26 years of drought, according to the bureau, so the framework sets initial operating guidelines just two years at a time, beginning with 2027 and 2028.

Nevada’s underground water basin can’t absorb the difference on its own. Smith closed the Las Vegas Valley basin to major new appropriations more than three decades ago, and the ground beneath the valley still carries the fissures from the decades of pumping that came before that order. As Washington negotiates the Colorado River two years at a time instead of settling on a multi-decade deal, the 85-year-old designation Smith signed in January 1941 is doing more work than it was ever built to do alone.