Aspen prepared the Final Supplemental EIS and EIR for the Prado Basin, Reach 9, and Norco Bluffs components of the Santa Ana River Mainstem Project in Orange, Riverside, and San Bernardino Counties. This project was unique in that Aspen conducted a GIS-based analysis of releases from Prado Dam under three different flood event scenarios. In the analysis, water levels downstream of the dam were delineated for different outflows from the dam outlet structure to indicate areas where riparian vegetation in the river channel would be affected. Engineering modeling of flow velocities in the downstream channel were also displayed to indicate areas where high flow velocities could damage vegetation.