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What we do
Fish passage assessments
Fish passage obstructions are present in almost every stream in the Napa River watershed. The RCD has compiled a list of these sites and has begun assessing them to determine their severity and to develop plans to fix them. Road crossings, dams, culverts, bridges, and debris jams all create.
Methods
- A fish passage site is screened using DFG criteria to determine whether it is a minor obstacle, partial barrier, or severe barrier.
- Based on this screening, a score of “Green”, “Gray”, or “Red” is assigned to each site for prioritization according to DFG fish passage criteria
- The amount of fish habitat upstream of each site is calculated from existing survey data or estimated in streams where surveys are lacking.
- Each site is surveyed for key dimensions and topographic details, and then modeled using computer software such as Fish Xing and/or HEC-RAS.
- Modeling results are used to determine the severity of the barrier for various target species and life stages.
- RCD biologists work with engineers to generate site-specific plans based on modeling results that will improve fish passage at the site.
- Implementation funds are sought once a design is in place.
Completed Assessments
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