Santa Margarita River Fish Passage Project: Implementation

This coastal resilience project will construct a new bridge over the Santa Margarita River to provide critical flood management, riparian restoration and public safety benefits, while restoring fish passage in a high priority endangered steelhead recovery river, as designated in the National Marine Fisheries Service’s (2012) Southern California Steelhead Recovery Plan. The project is located where Sandia Creek Drive crosses the Santa Margarita River, about two miles north of Fallbrook, CA in northern San Diego County. Removal of the fish passage barrier at Sandia Creek Drive, and replacement with a new bridge, will allow endangered steelhead access to 12 miles of protected upstream spawning and rearing habitat. The newly constructed bridge will pass 100-yr flow and increase resilience to catastrophic climatic events. This project will protect communities from recurring severe flood and fire events, re-establish the natural hydrology of the river in a major San Diego County floodplain, restore a regional wildlife corridor, enhance riparian quality over five acres for threatened and endangered species, and increase access and safety for thousands of residents, commuters and recreational visitors who use this bridge daily.

The five-acre project site contains over a dozen vegetation types and provides habitat for a variety of wildlife species in this critical wildlife corridor connecting the Santa Ana and Palomar mountains. These vegetation communities include southern cottonwood-willow riparian forest, southern riparian woodland, southern coast live oak riparian forest, southern willow scrub, southern riparian scrub, coast live oak and other mixed woodlands and chaparral. There is a tremendous biodiversity in this relatively untouched stretch of river, which will be improved through bridge replacement, restoration of the natural hydrograph and associated riparian restoration of a major San Diego County floodplain. The project will result in restoration of ~5 acres of wetlands and improve 15 acres of habitat for threatened and endangered aquatics species and nesting birds.

Construction started in January 2023 and progressed through the clearing stage for the approved bridge alignment. Upon inadvertent cultural discoveries, construction activities were halted in April 2023 while the MLD process is completed. The bridge will be re-located away from the culturally sensitive site, just upstream adjacent to the existing box culvert river crossing. Design refinement is underway that utilizes the design geometry and cut steel, while elevating the bridge approach. Project funding of $21M is secured and has remained intact to complete the bridge with a one-year delay. All parties seek to come to the right solution that respects tribal sacred area while providing passage for endangered steelhead and coastal resiliency. The bridge will be constructed over 1.5 years, with an anticipated completion date of 6/1/2025. While the project is currently fully funded, there may be additional costs for re-vegetation and habitat restoration in the coming year, and to bolster the funded Climate Crew activities.