Over 600 Miles of Instream Habitat Reconnected in the Blackfoot Watershed for Native Trout

In the spring of the year when rivers are running high and muddy, it might surprise you to learn that's also the time when westslope cutthroat trout start to move upstream-some migrating over 90 miles to get where they need to spawn! In the Blackfoot Watershed, we have two different species of native trout, westslope cutthroat trout and bull trout. Making sure these fish can navigate through those many miles is one focus of Big Blackfoot Chapter of Trout Unlimited.

What are some of the obstacles that trout encounter on their river journey? Undersized culverts, irrigation dams or dewatered streams can cause problems.

If a culvert is undersized, it acts like a fire hose in the stream creating velocities that are too high for fish to swim through and scouring the bed below the pipe, causing the culvert to become "perched" above the channel.

Often we will hear comments that all culverts are bad for fish. However, culverts can be a fine choice for a stream crossing as long as the pipe is sized and set appropriately so the stream channel isn't constricted. We work with landowners throughout the valley on upgrading problem culverts. In addition to restoring fish passage, these projects can help reduce road maintenance issues and decrease sediment inputs into a stream.

When the size of a stream or existing road system doesn't lend itself to a culvert, bridges are another option we have to work with. In 2008, we worked with the Lolo National Forest on upgrading the existing culvert on Cottonwood Creek on USFS Rd #477. Due to the size of the stream, a bridge was the best choice for the new crossing and by upgrading the structure, fish passage was restored to one-mile of habitat while ensuring the road system was stable.

Springtime is a busy time for irrigators and we have been fortunate to work with many of them on projects that ensure they get their water, while keeping trout out of ditches and allowing them to move freely throughout a stream. In the Blackfoot watershed, we have 35 different fish screens on irrigation diversions-three of which are on important trout streams flowing right through Seeley Lake. It's thanks in large part to the private landowners who have worked with us over the past 31 years that over 600 miles of instream habitat has been reconnected in the Blackfoot watershed!