Fish habitat in the Yankee Fork has been drastically altered as a result of mining activities in the Yankee Fork drainage and particularly where dredging occurred.  Dredging, which occurred intermittently between 1940 and 1952, obliterated the Yankee Fork stream channel and eliminated or substantially reduced the floodplain.  The new channel that formed was often trapped between the dredge tailings and the valley hillside, where it was unable to reestablish a natural meander pattern.  Further, flood-flows were contained between the hillside and dredge tailings resulting in increased stream energy, which mobilizes spawning gravels and wood out of the reach.  The inability for this area to naturally recover is also exacerbated by the removal of trees from the streamside.  

Timber harvest began occurring in the Yankee Fork in the mid-1800s and was conducted primarily to support mining.  “By…[1904], the hills for miles around Custer were denuded of trees, as huge quantities of wood had been used for homebuilding, mine supports, and mills.”  This timber harvest was followed, in the dredged area, by clearing to facilitate dredging.

Over the past several years, landowners, agencies, and conservation groups have partnered to implement several projects throughout the dredged reach.  Trout Unlimited is currently proposing to implement a habitat improvement project in the area between the Preachers Cove project, which was implemented during 2014, and the West Fork Confluence project, which was implemented during 2015 and 2016.  

Partners believe that this section of the Yankee Fork has the potential to be improved substantially with the addition of large wood.  Therefore, Trout Unlimited proposes replicating the approach that was recently used by Trout Unlimited and the Forest Service to improve fish habitat upstream from the dredged area.  That approach involves adding large wood to the stream channel in a manner that mimics streamside recruitment. That is, trees will be field fit in the stream to mimic natural conditions and will not be anchored.  No engineering design will be produced.  

We expect access in much of the area will be restricted, due to the presence of historic resources.  Therefore, a helicopter will be used to place most of the wood.  Additionally, 90 cubic yards of spawning sized gravel will be added at access points so that high flows can mobilize and deposit it in areas where the newly placed large wood creates low velocity areas, as occurs naturally.

This project will improve in-stream hydraulic and habitat complexity within the main-stem Yankee Fork River.  It will therefore enhance fish habitat for all life-stages of migratory and resident fish, provide refugia during high flows, provide cover during high and low flows, provide winter habitat for juvenile salmonids, and provide spawning areas for all salmonids. Salmonids that will benefit from this project include spring/summer Chinook salmon, summer steelhead, bull trout, and westslope cutthroat trout.  

In the fall of 2013, the Forest Service evaluated the amount of large wood loading in Warm Springs Creek, a reference area similar to the Yankee Fork but where anthropogenic activities were thought to have had little impact on large wood abundance (reference reaches).  Reference areas comparable to that portion of the Yankee Fork between Jordan Creek and Custer were found to have 96 pieces of large wood per stream mile.  The Yankee Fork from Jordan Creek downstream to the confluence with the West Fork is similar enough to the area from Jordan Creek to Custer that the same level of natural wood loading can be assumed. Therefore, natural levels of wood loading in the ½ mile long Preachers Plus reach will be achieved by adding 48 pieces of large wood.

Historically, many of the trees in the Yankee Fork were probably large spruce or Douglas fir.  We will attempt to mimic natural conditions by using 15 large (>24” dbh) and 33 smaller (8-18 dbh) trees in this project.  This will also reduce the probability that these trees will be mobilized and leave the project area.  Additionally, these trees will provide a mechanism to capture other pieces of wood moving through the system either as a result of this project or upstream inputs.  This should ultimately result in complex aggregates of large wood that create quality fish habitat.

The trees used in the project will come from the following off-site sources: Lightning Lake Road, the hillside adjacent to Preachers Cove, and Bonanza timber sale area.  All of these areas have been cleared by the Forest Service for timber harvest associated with salmonid habitat improvement.  Spawning gravel will consist of dredge tailings that were screened during the West Fork Confluence project but not needed for that project.

Besides creating a channel that flushes through large wood and spawning gravel, the Yankee Fork Dredge eliminated the floodplain by creating gravel piles throughout the area that was previously floodplain.  A large-scale channel and foodplain restoration project at Bonanza City is planned for implementation during 2018 and 2019.  In preparation for that project, Trout Unlimited will, during 2017, implement some initial activities for the Bonanza City project.  

Bonanza City pre-project (2017) activities include securing, potting, and growing in a nursery 500 upland plants that will be out-planted in the Bonanza City project following project implementation in 2019.  Additionally, during 2017, 25,000 yards of dredge tailings will be removed from the Bonanza City Project area.  

Dredge tailings will be removed by working with Custer County Road and Bridge to crush the gravel, to make suitable road material, and then hauling and spreading the crushed dredge tailings on the road.  Custer County will do the hauling and spreading and will pay a portion of the crushing costs.  A portion of the crushing cost will be paid under this contract.  This is a win-win for both fisheries and Custer County.  Custer County gets the dredge tailings at a reduced cost, and dredge tailings are removed from the Bonanza City project area and do not need to be stockpiled elsewhere.