Optimizing for Water Equity in the Colorado River Basin

Abstract

The Colorado River Basin is experiencing water shortages of increasing severity and frequency. Due to the scale of the Colorado River Basin, its multitude of end users, and ecosystems dependent on its consistent water supply, these water shortages present a dire problem. If the Colorado River ran dry it would lead to a loss of $1.4 trillion in economic activity [1] not to mention the fatal impact on wildlife, Western populations, and environmental systems within its watershed. Our work focuses on optimizing Lake Mead reservoir operations to support the Lower Colorado River Basin. We produce alternative reservoir operating rules to address historic and present environmental justice issues. Our final results will be fundamentally driven by the hydrological budget of the river system and by human and environmental needs both now and in the future. We couple the Borg multi-objective optimization algorithm with the RiverWare river model, a decision support system, to design operating rules that prioritize flows to Native American reservations and tribal groups and Mexico. Our work distinguishes itself from past optimization applications by explicitly considering climate change scenarios and potential impacts on water justice issues faced by Native American tribal communities. Our results aid in identifying promising reservoir management alternatives at Lake Mead for controlling droughts both now and under future possible climate conditions. This work can inform the redesign of the Basin's operating policies after the current Interim Guidelines expire at the end of 2025.