The Bureau of Reclamation published a Final Environmental Impact Statement on July 31 establishing an operational framework for managing Lake Powell and Lake Mead through 2036, a decision that will shape water access for approximately 40 million people across the American West.
The EIS designates an adaptive decision framework for the next decade, replacing the expiring 2007 Interim Guidelines that governed the Colorado River’s two largest reservoirs during a historic period of drought and declining water levels.
The Colorado River serves seven U.S. states, Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming, along with two Mexican states and 30 tribal nations. Lake Mead and Lake Powell together form the nation’s largest freshwater reservoir system by storage capacity.
The final document follows years of contentious negotiations among the basin states over how to allocate increasingly scarce water resources. The river has experienced a more-than-two-decade drought that reduced reservoir levels to historic lows and triggered unprecedented federal shortage declarations.
The adaptive framework allows the Bureau of Reclamation to adjust water allocations based on changing hydrological conditions rather than relying on fixed operational triggers. The approach is designed to provide flexibility as climate conditions continue to evolve.
Municipal water agencies, agricultural districts, and hydropower generators across the basin all depend on the operational rules governing releases from the two reservoirs. The framework will determine how much water each state receives in both normal and shortage conditions.
Tribal nations hold some of the most senior water rights on the Colorado River, and their participation in the EIS process has been a priority for the Bureau of Reclamation, the agency said.
The EIS is subject to a Record of Decision that will finalize the operational framework.