Prado Basin Feasibility Study

This Final Integrated Feasibility Report with Environmental Impact Statement/Environmental Impact Report presents a summary of the planning process, describes the affected environmental resources and evaluates the potential impacts to those resources as a result of constructing, operating and maintaining the Prado Basin Ecosystem Restoration and Water Conservation Integrated Feasibility Study. The Prado Basin study area, which includes a portion of the Santa Ana River downstream of the Prado Basin reservoir, encompasses portions of Riverside County, San Bernardino County and Orange County, California.  

The U.S. Army Corps of Engineers, Los Angeles District, is the lead federal agency responsible for implementing the National Environmental Policy Act and the Orange County Water District is the lead state agency responsible for implementing the California Environmental Quality Act. 

The study identified and evaluated a range of alternatives that restore the ecosystem of the project area in response to degraded habitats and ecosystem processes of the SAR, its tributaries and their associated riparian areas. The study also identified and assessed changes to the operation of Prado Dam to increase the effective yield of the Santa Ana River as a source of water to OCWD’s diversion and infiltration facilities downstream of the dam that supply water for the OCWD service area.

The Recommended Plan is Alternative 3, which includes both an Ecosystem Restoration Plan and a Water Conservation Plan. The Ecosystem Restoration Plan includes measures to remove invasive plants in four focal areas of the project area, cowbird trapping in three focal areas, plant native species in three focal areas, and restore riparian, floodplain, and in-stream habitat in the Chino Creek focal area of the project area. The Water Conservation Plan includes re-operation of Prado Dam for controlled release of water from Prado Dam to increase the effective yield of water from the SAR for diversion and infiltration at OCWD’s facilities located downstream of the dam, with incidental sediment removal to offset sediment accumulation from the incremental increase in water conservation operations. The Recommended Plan, Alternative 3, has been identified as the combined National Ecosystem Restoration and National Economic Development Plan. 

Additional Information

For further information, please contact USACE at the following address:

U.S. Army Corps of Engineers Los Angeles District
Attn: Stuart Strum, Project Manager (CESPL-PM-C)
915 Wilshire Blvd., Suite 930    
Los Angeles, CA 90017-3401
Phone: (213) 452-3862