Caribou/Targhee National Forest Fish Passage Projects

During a 2005 site visit, Trout Unlimited, in partnership with the Caribou/Targhee National Forest (CTNF), identified two barriers preventing migrating Yellowstone cutthroat trout (YCT) from reaching historic spawning habitat on national forest land in the upper reaches of Trout Creek and Little Burns Creek.  It was determined the two barriers could be replaced with minimal time and cost, providing access to three to four miles of spawning habitat on each creek the threatened YCT are in desperate need of.

Trout Creek

The Trout Creek project involved removing an old culvert beneath the McCoy Creek road providing passage to upper reaches of Trout Creek.  The existing structure consisted of a round, corrugated metal pipe that was perched, creating a barrier on the lower side of the culvert.  It was also undersized and not capable of adequately passing high spring flows.

The project was completed in the Fall 2005 by replacing the existing structure with an oval, corrugated structure.  The new structure uses internal baffling welded to the bottom to reduce stream velocity.  Additionally, natural gravel material was placed between the baffles to further enhance the overall passage characteristics for migrating YCT through the new structure. The new structure was designed and positioned for high water events and water movement.  This is not only beneficial for fish, but will also aid in long-term road maintenance.

Following the installation of the new structure, CTNF personnel documented fish in the upper reaches of Trout Creek confirming migrating YCT have found and are using their historic spawning habitat.  CTNF and TU personnel will continue monitoring the stream to ensure the new structure is working properly.

Little Burns Creek

The Little Burns Creek project involved removing an old culvert beneath the McCoy Creek road to provide fish passage to upper reaches of Little Burns Creek.  The existing structure was perched and created a barrier on the lower side of the culvert, preventing migrating YCT from reaching historic spawning habitat in the upper portion of the creek.  It was also undersized and not capable of adequately passing high spring flows.

In 2006, approximately 30 to 35 feet of road fill was removed and stored on site to gain access to the old structure.  The existing structure was used as a bypass until the new structure was in place.  The new culvert, which is considerably larger, uses internal baffling welded to the bottom to reduce water velocity.  Additionally, natural rock material was placed within the structure to provide more natural substrate and bottom conditions to further enhance the overall passage characteristics for YCT.

Little Burns Creek aligned to the old structure at a roughly 90-degree angle, which caused a damming effect on the upstream side of the culvert.  The channel was realigned with minimal disturbance to better provide for flooding or high spring flows and long-term water movement.

Once the new structure was in place the stored fill material was replaced and the road surface was brought back to grade.  Slit fencing was installed both up and downstream of the roadway prism to prevent sediment movement from entering the stream; the disturbed area was then hydro seeded with a native grass mixture.  As the new vegetation establishes itself the silt fencing will be removed.

In partnership with the CTNF, the site will be monitored for the next few years to ensure the new structure is functioning properly and YCT are able to migrate to their historic spawning habitat.  We expect fish to begin using this immediately and spawning in the upper reaches of Little Burns Creek during spring 2007.

Project Partners

Partners for these fish passage projects include:

• Caribou-Targhee National Forest
• National Fish and Wildlife Foundation
• U.S. Fish and Wildlife Fish Passage Program