ERC was the surface water resource specialist on consulting team led by URS that prepared an Environmental Assessment (EA) for the U.S. Bureau of Reclamation to analyze the effects of Green Mountain Reservoir Substitution and Power Interference Agreements between Colorado Springs Utilities and Western Area Power Administration (WAPA). These agreements provide Springs Utilities with additional operational flexibility in meeting their substitution obligations and provide a reliable source of municipal water to the customers of Colorado Springs Utilities. ERC used the State’s Colorado River Decision Support System model to evaluate diversions under Colorado Springs Utilities’ Continental-Hoosier System water rights and the hydrologic effects associated with EA alternatives. The model was configured to represent each of the EA alternatives and simulated to generate hydrologic output, including changes in streamflows and reservoir contents. Model data was used to analyze impacts on streamflows and reservoir contents and support evaluations of resources affected by changes in flow, including wildlife, aquatic resources, recreation, wetlands and riparian habitat, floodplains, and water quality.