Trabuco Creek Fish Passage Project at the Metrolink and I-5 Bridges

This fish passage project at the Interstate 5 bridge array and Metrolink Railroad Bridge crossing on Trabuco Creek addresses some of the most significant fish passage barriers in Southern California. Trabuco Creek is in the San Juan Creek watershed in Orange County, a high priority steelhead recovery river identified in the National Marine Fisheries Services Southern California Steelhead Recovery Plan (2012). The two barriers to fish passage at the I-5 and Metrolink crossings are coordinately being remediated due to their proximity.

The project, led by California Trout and the Design/Permitting Team of NHC, Mike Love & Assoc, Gannett Fleming and Stillwater Sciences, features complex technical design and large-scale construction that will a) remediate two adjacent barriers located about 0.5 miles apart in lower Trabuco Creek, b) provide steelhead passage through these barriers beneath the Metrolink railroad bridge and the I-5 bridge array, c) restore the 1/2 mile stretch of stream channel between the two structures, and d) improve infrastructure at the project site and provide access to historic spawning and rearing habitat 12 miles upstream. This project leverages upstream removal of >81 check dams in Trabuco and San Juan Creek by the Forest Service to improve habitat accessibility of native aquatic species. See a 2023 posting of the 3D renderings and animation of the fish passage solutions, and an article in The Osprey that describes the multi-stakeholder approach to endangered species management, transportation and flood conveyance infrastructure improvement and coastal resiliency planning.

The project is in final design phase. The next steps is securing funding for bid-ready documents, agency-approved construction permits and then phased construction. Fish passage design has been funded by California Department of Fish and Wildlife, National Fish and Wildlife Foundation, and Wildlife Conservation Board. Funding is currently being sought for construction, which is planned to start in 2025.