By Butler, A., Jerla, C, Nowak, K., Prairie, J, Oakley, B., Wilson, N., Zagona, E. (2015). “The Colorado River Basin Water Supply and Demand Study: Modeling to Support a Robust Planning Framework.” In Proc 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19–21, Reno, Nevada, USA.


The Colorado River provides drinking water to nearly 40 million people and supplies water to irrigate over five million acres of farmland across seven western states and is vital to agricultural and municipal needs within the United Mexican States. The Colorado River also supports numerous ecological and recreational resources, provides water for hydropower generation, and is the lifeblood for 22 federally recognized tribes within the Colorado River Basin (Basin).

As part of the Bureau of Reclamation’s (Reclamation) WaterSMART program, the Colorado River Basin Water Supply and Demand Study (Basin Study) was conducted by Reclamation and the seven Colorado River Basin States in collaboration with stakeholders throughout the Basin. The Study’s objectives were to assess future water supply and demand imbalances in the Basin over the next 50 years and develop and evaluate options and strategies to resolve the imbalances. To address the considerable amount of uncertainty in projecting the future state of the Colorado River system, the Study adopted a scenario planning approach that resulted in four water supply scenarios (each with over 100 future realizations), six water demand scenarios, and two reservoir operation scenarios. The combination of all of these scenarios is referred to as the baseline in the Basin Study. The Basin Study shows that by 2060, the median supply and demand imbalance in the baseline is approximately 3.2 million acre-ft, though it can range from 0 to over 7 million acre-ft. Though these estimates ignore both the effectiveness of using reservoirs to help meet demands in times of drought and the geographic disparity of supply and demand, it indicates that in the absence of any actions, there is potential for large imbalances in the future.