The Santa Ana River Mainstem Project is designed to provide flood protection to the growing urban communities in Orange, Riverside and San Bernardino Counties . The proposed improvements to the system cover 75 miles, from the headwater of Santa Ana River east of the city of San Bernardino to the mouth of the river at the Pacific Ocean between the cities of Newport Beach and Huntington Beach.
The project will increase levels of flood protection to more than 3.35 million people within the three county areas. The project includes seven independent features: Seven Oaks Dam, Mill Creek Levee, San Timoteo Creek, Oak Street Drain, Prado Dam, Santiago Creek and Lower Santa Ana River .
The rapid growth and development of Southern California has decreased effectiveness of the present flood control system. Areas that would absorb rainfall runoff have been reduced as well as the water holding capacities of reservoirs. Today, the most severe flood likely to occur along the river would cover more than 110,000 acres to a depth of three feet and would amount to more than $40 billion in economic losses.
The Santa Ana River Mainstem project is designed to provide flood protection for residences and business in the Southern California communities of Orange , Riverside , and San Bernardino counties. All three counties, collectively, are working closely with the U.S. Army Corps of Engineers to design and construct the project.
Environmental & Recreation
The project includes environmental features such as enhancement of a degraded marsh area at the mouth of the river, thereby providing significant value as wetland habitat for migrating waterfowl and the California least tern, a federally listed endangered species.
The plan provides for the acquisition of Wildlife and biological mitigation lands, restoring temporary loss of habitat values, cultural mitigation, and a 32 mile system of recreation trails including:
In the Santa Ana Canyon, 1,100 acres of floodplain has been preserved as open space. A resource, habitat and floodplain management plan has been developed to preserve open space and wildlife habitat in the area.
A marsh restoration program consisting of ninety-two acres of degraded wetlands at the mouth of the Santa Ana River has been purchased and restored through re-contouring and the planting of wetland plant species. This wetland is providing significant wetland habitat for migratory waterfowl and the California Least Tern, and other endangered species.