Reclamation just picked a preferred framework for managing Lake Powell and Lake Mead after 2026, and it isn’t a fixed decade-long formula. It’s a set of boundaries, with the real decisions still to come in guidelines Interior plans to reissue roughly every two years.
The Bureau of Reclamation has selected a preferred framework for managing Lake Powell and Lake Mead once current operating rules expire, setting new boundaries for reservoir releases, shortages, and conservation through 2036. The Final Environmental Impact Statement doesn’t lock in one fixed operating formula for the next decade. Instead, it sets outer limits for the shorter-term guidelines Interior expects to issue in roughly two-year stretches, while Basin states, tribes, and water agencies keep negotiating toward a consensus agreement.
The Final EIS is a significant step, not a final decision. Reclamation still must issue a Record of Decision and work out the guidelines that will govern annual releases and shortages once current rules lapse.
The Framework Sets Boundaries, Not Fixed Allocations
Under the preferred alternative, annual releases from Lake Powell could run from 5 million to 12 million acre-feet, depending on reservoir conditions. Lower Basin shortages could reach up to 3 million acre-feet, and the framework allows storing as much as 8 million acre-feet of conserved water in Lake Powell and 3 million acre-feet in Lake Mead, plus voluntary Upper Basin conservation of up to 200,000 acre-feet if hydrology allows. None of that is an automatic cut or a guaranteed allocation. These are sideboards, not commitments, and individual water users won’t know their real exposure until the shorter-term guidelines land.
Guidelines Will Shift Every Two Years, Not Once a Decade
Interior expects to issue new guidelines roughly every two years unless the Basin states agree on something longer, a real departure from the 2007 Interim Guidelines, which locked in reservoir coordination and shortage rules years in advance. For cities, farms, utilities, and industrial water users, that means more frequent reassessment than one static formula, and companies with operations in the Basin should treat this as a starting point for ongoing scenario planning, the same discipline increasingly applied to power and permitting timelines elsewhere in site planning.
The Numbers Behind the Flexibility
The push for a more adaptive framework tracks a widening gap between what the Colorado River Compact assumed and what the river delivers. The Compact split 15 million acre-feet between the Upper and Lower Basins based on early-20th-century flow estimates that averaged close to 18 million acre-feet a year. Reclamation says actual inflows from 2000 through 2024 averaged only 12.9 million acre-feet, while consumptive use from 2020-2024 ran about 13.1 million acre-feet: roughly 3.8 million in the Upper Basin, 6.5 million in the Lower Basin, 1.4 million to Mexico, and 1.4 million lost to evaporation. Unregulated inflow into Lake Powell this year is running at just 3.5 million acre-feet as of July, and the two reservoirs combined remain at their lowest storage since before Glen Canyon Dam started filling in 1963.
The preferred alternative still leaves room for the seven Basin states to reach their own consensus agreement and fold it in, something negotiators have struggled to do given how divided the Upper and Lower Basin remain on how shortages get calculated and shared. Reclamation opened the environmental review in June 2023, released a draft EIS in January without naming a preferred option, and received more than 18,000 comments, including 785 unique submissions, before settling on this version.
None of that resolves the uncertainty water-dependent industries across the Basin are working around. It sets the range of tools Interior could use, the kind of exposure water-dependent operators are already tracking through facility-level water risk data and watershed modeling, and through the scrutiny water now gets in site-selection decisions. The more consequential decisions, how aggressively Interior uses the tools it just built, are still ahead.