The current rules governing the Colorado River expire on September 30. On July 31 the Bureau of Reclamation identified its preferred alternative for what replaces them, and the organizing principle isn’t allocation. It’s whether the dams keep working.
Elevation, Not Acre-Feet
The numbers that drive the plan are physical. Hydropower generation at Glen Canyon Dam ceases below Lake Powell elevation 3,490 feet. Reclamation set a consultation trigger 10 feet above that, at 3,500 feet, which is where the agency has to start making decisions rather than modeling them. Water stored below 3,490 feet totals less than 3.743 million acre-feet and can only be released once, because below that elevation there’s no way to move it through the powerplant.
Annual releases from Powell range from 5 to 12 million acre-feet under the framework. Preliminary rules for 2027 and 2028 assume a Lower Basin shortage of 1.5 million acre-feet.
The structural change is the increment. Rather than locking a decade of operating rules in place the way the 2007 guidelines did, Reclamation will set operations in two-year blocks running through 2036. That’s an admission that hydrology forecasting past 24 months hasn’t been reliable enough to bind an entire basin to.
What the States Asked For and Didn’t Get
Arizona, California and Nevada pushed for physical modifications to the dams themselves. Nevada argued for what it called straight-forward engineering fixes. Reclamation declined, holding that dam modifications are separate federal actions requiring their own review rather than something that can ride along inside an operating-rules EIS.
That’s a procedural answer to an engineering problem, and it defers work that will eventually have to happen. Both Glen Canyon and Hoover currently carry Reclamation’s lowest-priority Dam Safety Priority Rating, and planning for hollow-jet valve refurbishment at Glen Canyon is ongoing. The valves are the bypass path around the powerplant, and they were not designed to run continuously at the volumes a sustained low-elevation scenario would demand.
Reclamation received more than 18,000 submissions on the Draft EIS. The Final EIS is available at the Reclamation Post-2026 program page.
The Construction Read
For contractors the signal is that a large federal water infrastructure program is about to move from planning into procurement. Valve and outlet-works rehabilitation, gate work, and instrumentation upgrades at two of the largest dams in the country are all sitting behind decisions Reclamation just scheduled itself to make in two-year windows.
That pattern is familiar. Federal water and navigation work tends to sit in authorization for years, then move quickly once the operating case becomes undeniable. The New Lock at the Soo spent decades in the queue before the Corps put $2.6 billion behind a second Poe-class chamber, and it moved because the redundancy argument finally became impossible to defer.
The Colorado River argument is at the same stage. Reclamation has now put in writing what elevation the hydropower stops at, and there are only so many two-year increments between here and that number.