Development and Assessment of Streamflow Projections Under Changing Climate Scenarios Over the Colorado River Basin

Streamflow projections by Bureau of Reclamation (Reclamation) and other water management agencies have traditionally been based upon historical streamflow records and have assumed that future mean streamflow and variability is adequately represented through past observations. Previous studies have indicated that as climate change impacts affect the hydroclimatology of the Colorado River Basin, temperature and precipitation changes directly impact the magnitude and timing of streamflow. The World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset has recently been made available through a joint effort between Reclamation, Santa Clara University, and the Lawrence Livermore National Laboratory and provides statistically downscaled climate projection data from a myriad of climate models over the continental United States. While most research regarding streamflow projections at the regional scale has focused on the utilization of teleconnection indices, little has been done using temperature and precipitation projections from the WCRP CMIP3 dataset. In this study, streamflow projections are derived using projections of temperature and precipitation from the WCRP CMIP3 dataset and National Weather Service River Forecast System. These streamflow projections are subsequently used to develop projections of Reclamation reservoir operations under changing climate scenarios.