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Fish Passage Assessments:


Since 1998, RTA has been a leader in California fish passage issues. In conjunction with the Five-Counties Salmonid Conversation Program, RTA inspected approximately 450 stream crossings in Humboldt, Del Norte, Trinity, Siskiyou, and Coastal Mendocino counties and performed detailed passage evaluations on 245 stream crossings. With the results of the RTA final reports, the counties submitted numerous proposals to state and federal funding sources to treat high-priority migration barriers. As of 2016, the Five-Counties have obtained approximately 12 million dollars in restoration funding to implement nearly 70 fish passage improvement projects. Approximately 160 miles of salmon and steelhead habitat was re-opened through these efforts.


Additional fish passage assessment projects completed by RTA include:

  • Marin County – inspected 172 crossings and evaluated 90 sites.

  • Santa Cruz County – inspected 209 crossings and evaluated 80 sites.

  • Strawberry Creek watershed - inspected 13 crossings and evaluated 11 sites.

  • San Mateo County – inspected 120 crossings and evaluated 32 sites.

  • Russian River watershed - inspected 545 crossings and evaluated 183 sites.

  • Corte Madera Creek watershed - inspected 48 crossings and evaluated 26 sites.

  • Morro Bay/Chorro Creek watershed – evaluated 12 sites.

  • California State Parks/North Coast Redwoods District - inspected 53 crossings and evaluated 29 sites.

  • California State Parks/Mendocino District -inspected 62 crossings and evaluated 14 sites.

  • Jackson State Forest/Mendocino County - evaluated nine sites.

  • City of Arcata - evaluated 33 sites.

  • North Western Pacific Railroad/Eel River watershed - inspected 66 crossings and evaluated 22 sites.

  • Skunk Train Railroad/Mendocino County - inspected 10 crossings and evaluated four sites.

  • Cow Creek watershed - evaluated passage at 11 sites.

  • Yurok Tribe - evaluated seven sites in the lower Klamath River.

  • Karuk Tribe - evaluated three sites in the mid-Klamath River.

  • Hoopa Tribe - evaluated 11 sites within the Hoopa Valley of the Trinity River.

  • Hopland Band of Pomo Indians - evaluated six sites.

We can work with you to tailor a fish passage assessment that meets the needs of your agency, entity, watershed group, or private landowner(s).  We’re able to cost-effectively conduct fish passage assessments ranging from several crossings to hundreds.  Although culverts through roads are a major type of crossing, RTA has also modified the CDFG protocol to allow for the assessment of hardened fords and low-elevation diversion dams.  Regionally, these types of barriers are much more prevalent in central-coast and south-coast California.

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