Blog: The interconnectedness of the Colorado River Basins

The Colorado River Basin is about 1,450 miles long, flowing through seven U.S. states -Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming- and Mexico. It provides drinking water for 40 million people, including one-third of the Hispanic/Latino population in the nation, supports five million acres of irrigated farmland in nine states, and fuels hydropower in another eight. 

Almost 30 decades of unprecedented drought caused by climate change and overuse of this water resource are drying up the Colorado River, which has hit low record levels and put the basin’s states at a crossroads. 

States of the Lower basin, like Arizona, California, and Nevada, recently reached a historic agreement to cut a total of 3 million acre-feet through 2026 in exchange for massive funding from the federal government. 

Although the water reductions are not as aggressive as proposed by the federal government earlier, this agreement is a step forward to saving the river and preventing the lakes Mead and Powell -the two largest reservoirs in the United States- from dropping to “dead pool” levels.  

Will these water cuts be enough to help save the Colorado River? We spoke with two experts from the Lower and Upper basins: Dr. Enrique R. Vivoni, HECHO’s HCLC member from Arizona and the Fulton Professor of Hydrosystems Engineering at Arizona State University (ASU) and the Director of the Center for Hydrologic Innovations, and Dr. Tom Romero from Colorado, associate professor at the University of Denver College of Law, also a faculty member and affiliate faculty member in the Department of History, to talk about the complex water laws and system that rule this vital water resource and possible collaborative solutions of the Colorado River Basin states for a sustainable future. 

Question:  What is the Colorado River Compact or the "Law of the River," and what's the role of this agreement of 1922 in the current Colorado River crisis? 

Dr. Enrique R. Vivoni:  At the turn of the 20th century, national goals for settling the American West were pursued by creating large irrigation projects that required dams. Managing such a large and diverse system, with many components, constituents, and competing water demands, is complex. Early efforts in 1922 established the Colorado River Compact as an agreement between states and the federal government to manage the water supply. Over time, the limitations of this initial agreement have been identified and addressed through a difficult set of interstate negotiations, and sometimes using the courts system. The “Millennium Drought” that began in the western U.S. and the Colorado River at the turn of the 21st century has shown the vulnerability of the hydrologic systems to a severe and prolonged period of reduced precipitation. At the heart of the problem is that the amount of water allocated to the various states exceeds the amount of water that can be reliably expected to be available. 

Dr. Tom Romero:  The Colorado River Compact was formed to provide an apportionment of the use of the waters of the Colorado River System to each state and avoid litigation. This agreement gave a structure and framework in which every state would ultimately get a certain amount of water and then craft its water law system. The compact divided the river into the Upper Basin (Colorado, Wyoming, New Mexico, Utah) and the Lower Basin (Arizona, California, and Nevada). 

Two assumptions -made during the compact’s creation- have driven challenges for the past 100 years. First, the belief was that more water would be available in the Colorado River. Many of the engineering models used for the compact were based on what we now know were rare wet years. Secondly, in the early 1920s, California emerged as one of the breadbaskets of agricultural development. Hence, its water allocation was the largest, leaving states like Arizona and Nevada with disadvantageous smaller water allocations. However, it is in these states where we have seen enormous growth in the last 20 or 30 years. 

Question:  The Colorado River Basin has hit lower record levels, threatening drinking water, agriculture, hydroelectric power, and local economies. What are the major differences between the water crisis management in the Upper vs. the Lower Basin states? 

Dr. Tom Romero:  The significant difference is addressing these issues from a water law perspective. Every state has its unique water laws. One of the challenges all over the Southwest is that there's always a mismatch between where the water is and where the people are. It means you need to create a massive amount of infrastructure to move water from one place to another, requiring an enormous investment at the local and state level and certainly through federal subsidy. To show some differences between the Basin states, for instance, in Colorado, we have specialized water courts and a presumption in our legal system that groundwater is connected to surface water. However, that's not true for places like Arizona or California. This makes water management very state specific and is all tied to that legal regime that every state has set up with the amount of available water within its borders. 

Question:  What can you tell us about the interconnectedness of issues and solutions for the Colorado River Basin?  

Dr. Tom Romero:  The biggest challenge is bringing people together to think collectively about how and in what ways we can continue to make the Colorado River basin serve 40 million people that rely on it. The other challenge is the legal system that allocates water rights but doesn’t do the job of cutting back water to maximize its availability to be used by as many people as possible. Although each has different interests, the states need to think more holistically about the basin as a whole. 

The federal government has started to be much more proactively engaged in getting the states of compact to think that, even though they have a specific allocation of water, the reality is that the amount of water might not be available. The federal government could intervene to change allocations and impose severe cuts, which is the biggest fear of every state. Therefore, they must come up with new creative ways and solutions collectively. 

Water planning is going to be essential for the future moving forward. In Colorado, we just started in 2016 and it has provided a framework for us to work with less water. 

Question: What multifaceted solutions are needed to help meet water needs for now and the future?  

Dr. Enrique R. Vivoni:  Long-term solutions for the water management issues of the Colorado River need to account for on-going and upcoming water availability reductions due to climate change. There is high certainty that water supplies will be reduced during the 21st century due to the impacts of warming on the snow hydrologic conditions in the river basin. Less snowfall, lower amounts of snowpack, and earlier snow melts will combine with higher evaporation rates to lead to drier soils, lower streamflow, and less water available in the river for the many competing demands. With that as a backdrop, water conservation efforts need to exceed what the present structural deficit requires. 

A new approach is needed in the discussion of solutions to the water issues in the Colorado River. These need to be informed with scientific evidence, datasets, modeling scenarios, and other tools generated by federal agencies, university researchers, and the private sector. To a certain extent, the current management context limits the range of possible approaches that could be taken. These constraints are important, but also could lead to a narrow set of possibilities. For instance, the ‘Law of the River’ that sets priority use rights is an example of such a constraint. Relaxing this constraint, as proposed in one of the federal alternatives in the face of the current drought, would allow for a different set of possible solutions to be considered. Similar ways of opening possibilities are needed along with a careful scientific and engineering assessment of proposed solutions. 

Question: Can better interaction among agencies or entities help in preparing for different future water scenarios?   

Dr. Enrique R. Vivoni:  Engaging a diverse set of voices, ranging from communities to water management agencies, is essential for arriving at solutions that are feasible to implement and equitable for those involved. The process by which these stakeholders are engaged is time consuming and difficult, but if done appropriately yields improved outcomes. Given the existing differences among the various sectors involved, it is important to establish some guiding principles for interacting with future water scenarios. First, the providers of such scenarios need to establish credibility in the methods being applied with respect to their scientific and engineering basis. The future scenarios must address the key decisions that need to be made through the stakeholder engagement process. Finally, the modeling scenarios and the scientists and engineers engaged in building them must be considered unbiased in the negotiation process by other participants. Through our work, we have found that establishing these principles aids in the discovery process, which enlightens all involved as to the complex nature of the Colorado River and its evolving response over time.

Question: What are the options for balancing water demand and supply in an uncertain future? 

Dr. Enrique R. Vivoni:  The scientific community has reached a consensus that the future of the Colorado River will be hotter. Since water supplies depend largely on snow-driven hydrology, which is highly sensitive to warming, a hotter future will create significant changes in the amount and timing of water available. There is more uncertainty regarding the amount of precipitation that will fall each season of each year. It is likely that drought periods will include wet years or that wet periods. Nevertheless, the warming effects will outweigh any foreseeable increases in precipitation. There is a need to recognize that the current structural deficit, where water demands outpace water supplies, will worsen if not for interventions at multiple levels of governance and action. The “Millennium Drought” has accelerated a much-needed conversation about water availability, uses, rights, and responsibilities that is needed now in light of what the future will hold. 

Dr. Tom Romero:  It would be in the basin states’ best interests to renegotiate the Colorado River Compact or the "Law of the River." I say this as an academic, but I don't think this will politically happen. This over 100-year-old compact should be scrapped and should be thought of anew.  

We have an opportunity to keep all the best of the old compact and to also bring to the table sovereign Tribal Nations and Tribes that have water claims along the river and Mexico, using 100 years of technology advancements, climate modeling, and a better understanding about how each of the states wants to develop. We should take full advantage of these opportunities to use the best science, politics, and all lessons learned in the last century to create a new agreement.  

States have very different interests, different visions about growth, nevertheless, they share a vital resource that they all rely on. This collective thinking and action would put us in the best position to manage such a major challenge we face today and in the future.