Introduction
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 that $15 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:
Santa Ana Canyon of which approximately 1,123 acres of canyon lands will be acquired.
A resource, habitat and floodplain management plan has been developed to ensure
that no changes take place in the floodplain that might affect either releases from
Prado Dam during a flood event, or the 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.
