This project applied the FISHPass barrier prioritization tool to the Smith River watershed in Del Norte County, California — the largest undammed river in the state — to develop an optimized list of fish passage barrier removals for the benefit of Coho salmon, Chinook salmon, steelhead, coastal cutthroat trout, and Pacific lamprey. Field verification of 82 sites updated the California Passage Assessment Database and demonstrated the importance of accurate input data for barrier prioritization modeling. Note: FISHPass has since been phased out in favor of the National Barrier Prioritization Tool developed by the NFHP National Aquatic Connectivity Collaborative.
Project Name: Developing a Foundation for Fish Migration Barrier Removals in California’s Largest Undammed River: an Application of FISHPass in the Smith River
Location: Smith River watershed, Del Norte County, California. The Smith River is California’s largest undammed river and flows into the Pacific Ocean near Crescent City. The project covered the mainstem and major tributaries including the South Fork, Middle Fork, Hurdygurdy Creek, Rowdy Creek, Knopti Creek, Griffin Creek, Mill Creek, and the Smith River Plains lowlands. The watershed spans from near the Oregon border to the Pacific coast.
Historical Fish Presence: The Smith River watershed is one of California’s most important watersheds for wild anadromous fish conservation. Species present and benefiting from this project include Coho salmon, Chinook salmon, steelhead, coastal cutthroat trout, and Pacific lamprey. The watershed contains approximately 450 miles of potential anadromous salmonid habitat (updated from a prior estimate of ~400 miles as a result of this project’s improved hydrography). Multiple recovery plans and reports identify fish passage barrier removal as a high-priority restoration action in the Smith River.
Project Lead: Ross Taylor and Associates (RTA)
Project Partners: Pacific States Marine Fisheries Commission / PSMFC (contract administrator and GIS support – Brett Holycross); California Trout / USFWS (Damon Goodman – site visits and R-code modeling); Real Time Research (Quinn Payton – R-code development); Smith River Alliance (site access and local knowledge); California State Parks; U.S. Forest Service; Tolowa Dee-ni’ Nation / Smith River Rancheria; Green Diamond Resource Company; Alexandre Farms / Reservation Ranch.
CFPF Funding: Funded by the CA Fish Passage Forum under Grant No. 21-019G, administered by PSMFC. Specific dollar amount not stated in the report.
Project Description: The project applied the FISHPass decision support tool — which uses the OptiPass™ optimization model and California Passage Assessment Database (PAD) data — to the Smith River to produce a prioritized list of fish passage barriers for remediation. Key activities included: reviewing existing PAD data; conducting seven days of field reconnaissance at 82 locations in summer 2021 to ground-truth sites listed as “unassessed” or “passage status unknown” and identify 41 additional sites absent from the PAD; updating the PAD and Baseline Fish Habitat (BFH) layer with higher-resolution hydrography (NHDPlus-HR); and running multiple FISHPass scenarios using both coarse passability scores and FishXing hydraulic model results. Scenarios compared current barrier status versus a pre-remediation baseline and evaluated the sensitivity of coarse versus FishXing-derived passability scores. The project also assessed the performance of the FISHPass model relative to the CDFW Restoration Manual’s existing score-and-rank methodology. The top current priority barrier identified is the dam at the Rowdy Creek Fish Hatchery (PAD #721877), with 13.8 miles of upstream habitat.
Expected Completion: Summary 2022
Project Effectiveness: The project demonstrated that accurate, ground-truthed PAD data significantly improves FISHPass outputs — a 10-site run using revised data identified 22.1 miles of potential upstream habitat compared to only 16.4 miles using publicly available PAD data. Field verification found that 17 previously remediated sites had been well-selected, with FISHPass independently selecting 7 of the top 10 pre-remediation priority sites. The project also revealed that the CDFW score-and-rank methodology performed comparably to FISHPass, selecting 70% of the same top-ten sites. The project updated the BFH layer, expanded modeled anadromous habitat from ~400 to ~450 miles, and identified 41 previously unrecorded stream crossings. The report concludes that FISHPass is a useful prioritization tool but depends critically on current PAD and BFH data quality. Note: FISHPass has since been phased out in favor of the National Barrier Prioritization Tool developed by the National Aquatic Connectivity Collaborative, which builds on the conceptual foundation that this and similar projects helped establish.