Supplemental-Santa Ana Mainstem Project

Santa Ana River Mainstem Project Location: Orange, Riverside and San Bernardino Counties, California


The Santa Ana River is the largest flood threat west of the Mississippi. Existing flood facilities are inadequate to accommodate forecast milestone flooding, given the extensive growth and development that have occurred within Orange, Riverside, and San Bernardino Counties. Santa Ana River Mainstem Project (SARP) is a Congressionally authorized flood protection project for the River, from its headwaters in San Bernardino National Forest to its ocean outfall in Huntington Beach.

The U.S. Army Corps of Engineers is the federal lead agency, working in conjunction with the Local Sponsors: counties of Orange, Riverside, and San Bernardino. LSA served as an extension of County of Orange staff and provided environmental consulting services as needed. We prepared and reviewed supplemental NEPA and CEQA documentation for project amendments and updated Orange County’s Mitigation Monitoring Program annually. Our services included biological surveys, habitat mapping, and reporting preparation. LSA facilitated Interagency coordination with Orange, Riverside, and San Bernardino Counties, U.S. Army Corps of Engineers, and other agencies as needed. We also provided consultation services regarding the Endangered Species Act, Clean Water Act, and other applicable regulatory requirements and prepared a Habitat Management Plan for the Santa Ana River Canyon section downstream of Prado Dam.