Published: April 23, 2024 By

The Colorado River is undergoing a big change in management that has the potential to affect nearly forty million people who live in the Colorado River Basin and rely on Colorado River water. 

Flowing through more than 246,000 square miles in seven U.S. states and Mexico, the Colorado River Basin waters are governed by multiple documents known collectively as the Law of the River. In 1922 the Colorado River Compact established the framework to apportion water supplies between the river’s Upper and Lower Basins, with each basin allocated 7.5 million acre-feet (MAF) annually. Due to the various federally authorized projects in the basin, the Bureau of Reclamation (Reclamation), situated in the U.S. Department of the Interior, plays a prominent role in water management. Over-allocation and structural deficits have forced Reclamation to constantly update its Colorado River management plans - the latest 2007 Interim Guidelines are set to expire in 2026, which means that Reclamation must begin the process of developing a “multi-year NEPA process that will identify a range of alternatives and determine operations for Lake Powell and Lake Mead and other water management actions for potentially decades into the future.” 


Due to the complexity and scope of the task, as well as the worsening conditions facing the Colorado River Basin, any thorough, inclusive, and science-based decision-making process will need to be supplemented by environmental and social justice considerations in order to account for the diverse priorities of the various stakeholders dependant on the River for survival. 


In June 2023 Reclamation announced its intent to prepare an Environmental Impact Statement (EIS) as part of the required Post-2026 NEPA process, and has since published a Notice of Intent (June 2023) as well as a Scoping Summary Report (October 2023). The Post-2026 process is currently at the alternatives selection phase, wherein Reclamation will consider the various submissions of operational alternatives, and “develop a broad range of reasonable alternatives for analysis” in the Draft EIS, expected to be released in December 2024.


At this point, five major proposals have been submitted to Reclamation as part of the EIS operational alternatives analysis. In early March 2024, the Colorado River Upper and Lower Basin States submitted separate and competing plans for Reclamation’s Post-2026 Colorado River Operations Alternatives Development. Around the same time, a coalition of 20 basin Tribes submitted a Joint Letter to Reclamation. Additional submissions include an alternative from the environmental NGO community (entitled “Cooperative Conservation”), and finally, a proposal from three Colorado River Research Group (CRRG) members. 


The plans from the Upper and Lower Basins reflect ongoing tensions between the basins about curtailments and allocations of the diminishing water supply of the Colorado River. The Lower Basin’s plan proposes a new structure in which total basin storage dictates water cuts, with equal cuts across the basin at lower storage levels and cuts to only Lower Basin users at higher levels. The Upper Basin’s plan proposes a different schedule of Lake Powell releases, and doesn’t anticipate new curtailments to Upper Basin users under low flow conditions beyond what naturally occurs due to diminished streamflows. Despite these disagreements, the basins have agreed that it is the Lower Basin’s responsibility to address the structural deficit. 


In the “Cooperative Conservation Alternative," the conservation organizations look at the essential role of natural systems in the Colorado River Basin, and propose a set of operational activities that could help maintain the “integrity of Basin ecosystems, while working to support resilient communities, Tribal nations, businesses and agriculture.” The alternative calls for more certainty in the Post-2026 alternatives operational guidelines, and emphasizes the importance of a more holistic, all-inclusive approach that would consider all who rely on the basin.


The proposal authored (and submitted independently) by three CRRG members “Managing the Powell/Grand Canyon/Mead ecosystem after 2026,” suggests more flexibility in annual releases and adaptive allocation of water storage in both Lake Powell and Lake Mead. This “adaptive management” proposal specifically focuses on reducing consumptive use during years of unusually low runoff and reservoir storage. John C. Schmidt, Eric Kuhn, and John Fleck explain that this more flexible approach would enable releases to be optimized and meet environmental, recreational, and cultural goals, better address tribal concerns and objectives, and simultaneously fulfill water-supply objectives. 


The Tribes’ letter differs from the other proposals, in that it focuses on tribal principles and environmental social justice concerns that are for the most part left out of the other submissions. The “letter of principles” calls for equal status for Tribes in developing new river management guidelines, and insists that Reclamation protect the senior water rights of the Basin Tribes against proposed cuts or development caps. The Tribes are the River’s most senior water rights holders, but a lack of infrastructure and historic inequity has left most of the federally-reserved water rights unquantified and unused. 


“Each Tribe has a unique history and relationship with the basin, and variously depend on the waters of the Colorado River and its tributaries for a variety of purposes, including cultural and religious activities, domestic, irrigation, commercial, municipal and industrial, power generation, recreation, instream flows, wildlife, and habitat restoration.”


Twenty-two of the Tribes have recognized rights to use 3.2 million-acre feet of Colorado River system water annually, which is approximately 22 to 26 percent of the Basin’s average annual water supply. This is a significant amount of water for any stakeholder to claim, and still be left out of major negotiations as the Tribes usually are. Reclamation needs to make it clear in its Post-2026 process that the Tribes are a vital and primary actor in the management of the Colorado River. Furthermore, incorporating a co-management structure or cooperative framework whereby the Tribes could more fully participate and gain sovereign recognition would incentivize more creative, holistic approaches to river management and conservation.


These issues, and much more, will be explored in detail in the University of Colorado Law School Getches-Wilkinson Center’s upcoming water conference June 6-7th: “Next Chapters on the Colorado River: Short-Term Coping, Post-2026 Operations, and Beyond.”  




In March 2024, a final Supplemental Environmental Impact Statement (SEIS) was released by Reclamation, reflecting the ongoing collaborative effort to update the current interim operating guidelines for the near-term operation of Glen Canyon and Hoover Dams. The SEIS was drafted in April 2023 as a reaction to the ongoing drought, to address the impacts of climate change. The plan outlines three preferred alternatives that will lead to at least 3MAF of water savings through 2025, when the current guidelines expire. See Bureau of Reclamation, Near-term Colorado River Operations: Final Supplemental Environmental Impact Statement, US Department of the Interior, (March 2024).


3 All of the alternative submissions can be found at the Water & Tribes Initiative website, under the banner “Proposed Alternatives for Post-2026 Operating Guidelines.” For the CRRG members article, see: