Colorado River Operations and Planning in a Changing Climate

During the period from 2000 to 2005, the Colorado River experienced the worst drought in approximately one hundred years of recorded history and that drought continues. In 2005 Reclamation's Upper and Lower Colorado Regions initiated a National Environmental Policy Act (NEPA) process to develop Lower Basin shortage guidelines and coordinated management strategies for the operation of Lake Powell and Lake Mead. Implemented in 2007, the guidelines provide a prescriptive methodology to determine the annual releases from Lake Powell and Lake Mead for an interim period (through 2026). They focus on encouraging conservation of water in the Lower Basin, consideration of reservoir operations at all water levels, and gaining valuable experience operating the reservoirs to improve the basis for making future operational decisions during the interim period and/or thereafter.

In 2004, Reclamation's Lower Colorado Region initiated a research and development program, collaborating with other federal agencies and universities, for the purpose of enabling the use of new methods for projecting possible future river flows that take into account increased hydrologic variability and potential decreases in the river's annual inflow due to a changing climate. As part of this effort and in conjunction with the development of the Interim Guidelines, additional analyses were included in the Environmental Impact Statement that considered the impacts of greater hydrologic variability than have been seen in the 100-year record.

The Interim Guidelines are in place through 2026 and include a provision that “Beginning no later than December 31, 2020, the Secretary [of Interior] shall initiate a formal review for purposes of evaluating the effectiveness of these Guidelines.” Further knowledge of the impacts of a changing climate, both realized and projected, will be critical when such a review is initiated. Accordingly, the Colorado River Basin Water Supply and Demand Study (Study) under Reclamation's Basin Study Program was initiated in the beginning of 2010. The purpose of the Study is to conduct a comprehensive study to define current and future imbalances in water supply and demand in the Colorado River Basin over the next 50 years to develop and analyze adaptation and mitigation strategies to resolve those imbalances. This Study and other research efforts through continuation of the research and development program will further Reclamation's ability to analyze the potential impacts of climate change and use that information in water and power operations and planning studies to be able to adapt, as appropriate, the operation and management of the river to a changing future climate.