West-central Alberta Culvert Remediation Project, 2023–2025
Final Report
Author(s)
Chad Judd, B.Sc., P.Biol.
Mike Rodtka, Dip. Res. Tech., B.Sc., M.Sc., P.Biol.
Summary
Native trout in Alberta have declined in abundance and distribution over the past century. Many factors have been implicated in their decline, including habitat fragmentation and degradation from watercourse crossings. To evaluate the success of crossing remediation to address habitat fragmentation, we sampled 26 crossings in west-central Alberta during the summers of 2023 to 2025. Our fish sampling and habitat assessment methods allow us to evaluate fish passage and habitat qualities above and below crossings that have been remediated. We captured 1,056 fish of nine different species with brook trout being the most abundant. Fish were found above most remediated crossings, the majority of which had either submerged or embedded outlets allowing for fish to enter the culverts. The remediated crossings provided fish with similar habitat qualities including temperature, dissolved oxygen, conductivity, and turbidity above and below the crossings, and there were no significant differences in habitat qualities between culverts and bridges. To monitor early fish response to reconnected stream habitats, we also electrofished and measured habitat in watersheds above four recently remediated crossings. Fish were found in two of the watersheds and in all cases the habitat was cold and complex with gravel and cobble substrate, woody debris, and sections of undercut banks, qualities preferred by native trout.