PROJECT BACKGROUND

Among members of the salmon family, the Southern California Steelhead (Oncorhynchus mykiss), or simply steelhead, is the only species for which a thriving population was commonly found in coastal waters and within watersheds of Southern California, from Point Sal south to the U.S./Mexico border. Throughout this coastal region, large numbers of adult steelhead historically swam from the ocean into rivers and streams between winter and spring to migrate further upstream through coastal watersheds, including the Los Angeles River Watershed (LARW), and spawn in upper reaches of mountainous tributaries. After rearing in freshwater systems, juvenile steelhead reached maturity and many of them were able to migrate back to the ocean to complete the life cycle. But in the early 20th century, the Southern California Steelhead population started to decrease abruptly due to the negative impacts of overfishing and urbanization, including constructions of dams, flood control structures, and other man-made barriers that precluded the natural passage of fish and their upstream (adults) and downstream (juveniles) migrations throughout urban coastal watersheds. The population abundance plummeted to such low numbers that the Southern California Steelhead Distinct Population Segment (DPS) has been listed in the federal Endangered Species Act (ESA) since 1997. Similarly, steelhead was a common species in the LARW until the 1940s, before the population drastically decreased due to the impact of excessive recreational fishing pressure and the presence of man-made physical structures and barriers, in both the Los Angeles River mainstem and some of the upper tributaries. However, some of these upper tributaries are still home to isolated populations of rainbow trout, which is the non-anadromous life history form of O. mykiss. These populations can interbreed with steelhead, and either of these two life history forms can produce offspring that exhibit the alternate form (i.e., resident rainbow trout can produce anadromous progeny and vice-versa). Some of these rainbow trout populations are considered relicts of native coastal steelhead lineage that have adopted a resident life history in freshwater systems, with juveniles that cannot migrate back to the ocean and adults that complete their life cycle in freshwater. The LARW is considered an important region to support the viability of the remaining populations of Southern California Steelhead due to its key role in potentially maintaining resident rainbow trout populations of coastal steelhead lineage in its upper tributaries. In fact, recommended recovery actions for the LARW listed in the NMFS Southern California Steelhead Recovery Plan, issued in 2012, include habitat restoration, remediation of passage barriers, and other actions that address major stressors and limiting factors for the Southern California Steelhead DPS.

OBJECTIVES

The main objective of the LAR FPHS Project is to conduct science-based research and design (Basis of Design Report to 60% design drawings, CEQA, and initial permitting) of fish passage and habitat structures that address limiting factors for steelhead and other native fish within a 4.8-mile section of the concrete-lined Los Angeles River through Downtown Los Angeles. The Project provides opportunities to address watershed-wide data gaps. In turn, this information can be used to fill these gaps and to support future projects aimed to enhance steelhead recovery throughout the LARW, and to identify other potential suitable sites for fish passage projects across the Los Angeles River and its upper tributaries.

SCOPE & STATUS

The LAR FPHS Project started in January 2020, and is planned for completion in December 2021.

Q&A

Why are we doing this project? The Council for Watershed Health (CWH) and Stillwater Sciences are leading the LAR FPHS project in partnership with the City of Los Angeles, who is the lead agency, as well as Reclamation, SCCWRP, NMFS, USACE, the County of Los Angeles, CDFW, USFWS, RWQCB, ASF, and FoLAR.. The city has adopted sustainability and biodiversity plans to bring back native species, including steelhead and other native fish among many other species, with an ultimate goal of improving connections between people and nature. This project is intended to create steelhead fish passage in the Los Angeles River as a migration corridor to the upper tributaries of the LARW spawning grounds, and is a pilot project that can be replicated in other concrete-lined channels to provide fish passage and habitat structures for migrating fish. Watershed scientists are working to address study questions focused on watershed-wide limiting factors to steelhead recovery. This project provides an opportunity to align with related USACE, City and County restoration projects, scientific studies, and ongoing watershed and Los Angeles River monitoring plans and efforts. These include, but are not limited to, the following project objectives: 1. To implement key features of the Congressionally Authorized L.A. River Ecosystem Restoration Project, Alternative 20 Integrated Feasibility Report. 2. To implement conceptual USACE Arroyo Seco Ecosystem Restoration Watershed Study recommendations of fish passage, barrier removal, stream naturalization, and fish habitat improvements to support multiple life stages of rainbow and steelhead trout and re-establishment of resident trout populations. 3. To improve conditions for other native fish in the LARW and upper tributaries, including Santa Ana sucker, arroyo chub, unarmored three-spine stickleback, speckled dace, Pacific lamprey, and other aquatic species and wildlife. 4. To implement adopted plans, policies, and recommendations of federal, state, regional, and local agencies, including NMFS’s Southern Steelhead Recovery Plan, City of L.A.’s L.A. River Revitalization Master Plan, Greater L.A. River Integrated Regional Water Management Plan, County L.A. River Master Plan, L.A. Mayor’s Sustainability Plan, L.A. Biodiversity Plan, and others. 5. To enhance ecological connectivity between in- and off-channel areas to maximize the urban biodiversity and ecosystem benefits (environmental and socio-economic) of the project. Will we really see steelhead in the LA River again? Yes. If effective fish passage design and conditions are implemented, steelhead will be able to migrate to upper tributaries of the LARW and ultimately complete their life cycle. Steelhead thrive in cool, clean, well-oxygenated water. The LARW’s water quality, temperature, vegetation (providing shade and natural cleansing of flows), and stream conditions (e.g., dissolved oxygen levels, velocity, sediment load, etc.) will need to improve to support total maximum daily loads (TMDLs), water quality thresholds set by the RWQCB under the Clean Water Act, as well as steelhead suitability requirements. A healthy riverine and aquatic ecosystem in the Los Angeles River will address the needs of both fish populations and local communities. Many Angelenos have expressed interest in a clean LA River, with prospects of recreation and enjoyment. By meeting the needs of native fish species in the LA River, this pilot project promotes species recovery as a top priority, with numerous multiple benefits for Angelenos in perpetuity. Cost

How is the “project design” being funded?

The Wildlife Conservation Board has funded this project under a State of California Prop. 68 Fish Passage grant (WC-1922DC) in the amount of $1.356M. The City and other partners, including Stillwater Sciences, SCCWRP, ASF, and FoLAR, are providing in-kind services as matching funds for the project. Future phases of the project will include 100% design, permitting, and construction.

CONTACT

For more information please reach out to the LAR FPHS Project Manager, Andrea Dell’Apa adellapa@watersheadhealth.org or 213-229-9945 - ext.5.

RESOURCES

• Recovering Steelhead Trout Populations in the L.A. River Watershed [ArcGIS StoryMap]
• Project Profile [PDF]
• Q&A Fact Sheet [PDF]
• Final Techical Memorandum: Conceptual Ecological Model and Limiting Factors Analysis for Steelhead in the Los Angeles River Watershed, September 2020