The purpose of the SARMP, including the Santiago Creek component, is to provide flood risk reduction to areas susceptible to flooding within the counties of San Bernardino, Riverside, and Orange. The need for the project is due to significant flooding along the Santa Ana River – including Santiago Creek – within Orange, Riverside, and San Bernardino counties in California, which has been documented since at least 1897. According to USACE documentation, the largest recorded flooding event by peak flow occurred in 1938 following a series of large storm events, the flooding caused at least $4,000,000 in damages within Orange County along (1938 price levels). In February 1969, a series of significant storms resulted in approximately $22,000,000 in damages within Orange County (1969 price levels) and at least twelve deaths. Unprotected banks along Santiago Creek are subject to erosion which could cause damage to residential and commercial (i.e., Oakridge Private School) developments as well as infrastructure (i.e., Villa Park Road) along the creek.
This objective of the Santiago Creek project is to safely pass the 1% annual chance of exceedance flood event (100-year storm). The project consists of slope stabilization improvements to the Bond, Blue Diamond, and Smith Basins to reduce the risk of erosion during flood events, and improvements to the Santiago Creek channel downstream of Interstate 5 to the confluence of the creek with the Santa Ana River for erosion protection and conveyance.
The design update for the Santiago Creek project is being funded 100% by federal funds from the Bi-Partisan Budget Act of 2018.