Vegetation representation influences projected streamflow changes in the Colorado River basin

In contrast, the previous VIC configuration, which is used to inform decisions about future water resources in the Colorado River basin, projected an 11.7% decrease in annual streamflow. Both VIC configura-tions simulated similar amounts of evapotranspiration in the historical period. However, the MODIS-based VIC con -figuration did not show as much of an increase in evapotranspiration by the end of the century, primarily within the upper basin's forested areas.

Differences in evapotranspiration projections were the result of the MODIS-based vege-tation parameters having lower leaf area index values and less forested area compared to previous vegetation esti-mates used in recent Colorado River basin hydrologic projections. These results highlight the need to accurately characterize vegetation and better constrain climate sensitivities in hydrologic models.