The U.S. Bureau of Reclamation has released its Near-term Colorado River Operations Draft Supplemental Environmental Impact Statement, analyzing three paths forward for managing the Colorado River in light of the potentially dire consequences if they fail to act.  The Draft SEIS describes three potential choices without making a specific recommendation: (1) do nothing, (2) impose reductions to Lower Basin state allocations in accordance with the priority system that has developed under the Law of the Colorado River, or (3) impose reductions to Lower Basin state allocations in equal percentages.

Under the “No Action Alternative,” USBOR concluded that there was a potential for water levels to reach “dead pool” at either or both Glen Canyon Dam and Hoover Dam.  If dead pool is reached, the water level would be so low that water could not be released to generate power and provide water downstream.  

The primary difference between the No Action Alternative and both Action Alternatives is that the Action Alternatives would protect the volume of water required to continue generating power at Glen Canyon Dam. 

The differences between Action Alternative 1 and Action Alternative 2 are in the impacts to the downstream users.  Under Action Alternative 1, Arizona would absorb the bulk of the reductions due to the junior priority status of the Central Arizona Project as specified in Section 301(b) of the Colorado River Basin Project Act.  Under Action Alternative 2, the reduction in deliveries would be allocated in equal percentages between Nevada, Arizona, and California, with California, in particular, being required to take substantially greater shortage reductions than under Alternative 1. 

To allocate reductions in equal percentages, USBOR referred to management decision precedence in both the Upper Basin and in the Lower Basin, specifically Secretary Udall’s decision in 1964 to impose equal percentage reductions to address a reduction in flows at Glen Canyon Dam.  USBOR also referred to the Secretary’s authority under the 2007 Interim Guidelines to “operate Reclamation facilities to address extraordinary circumstances.”

Comments on the Draft SEIS must be submitted by May 30, 2023.  A final SEIS is expected in late summer 2023.