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Idaho Fish and Game

A group of deer in the City of Cascade approach the driver's side window of a vehicle during the winter of 2023.

Habitat restoration efforts take advantage of local wildfires

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The Lemhi River consisted historically of a large active floodplain containing complex fish and wildlife habitats.  The Lewis and Clark expedition noted in their journals an observation of a fish weir constructed by Native Americans that spanned multiple channels, suggesting that the river system contained a network of braided channels.  The Lemhi River Valley is well known for its abundant resources that supported, among other things, the fur trade, mining, and agricultural development. With an influx of people, the town of Salmon was established. As the region grew in population, land development expanded throughout the valley.  Agricultural demands and associated infrastructure needs (e.g., transportation) resulted in modification of the historic floodplain, leading to straightening and channelization of the Lemhi River.  The once active floodplain became isolated from the river, and side channel, riparian, and instream habitats that are important for fish were lost

Map

  In recent years, Idaho Department of Fish and Game (IDFG) has worked with landowners in the Lemhi River Valley to return the Lemhi River to a more natural state through a variety of restoration projects. The goal of these projects is to create a diversity of habitat types that are crucial for anadromous and resident fish of all life stages (i.e., fry, parr, presmolt, smolts, and adults). One of the limiting factors for fish in the Lemhi River watershed is overwintering habitat for juvenile fish, particularly for Chinook Salmon.  Thus, IDFG biologists began to focus on improving habitat for juvenile fish. In an effort to reduce water velocities and create a variety of good habitat features, biologists prescribed actions that included braided channels, meanders, large woody debris structures, deep pools, and grading to re-establish the floodplain.  Many of these projects require a large amount of woody debris to create ideal habitat structures.  Some of these structures that use large woody debris include bank roughening to provide bank stabilization and erosion prevention and engineered log jams to create scour pools.

Downed tree pile

With such a high demand for timber, IDFG had an opportunity to acquire timber from a couple fire breaks that were created in 2021 to limit fire growth. These breaks were cut for the Trail Creek fire north of Salmon along the Idaho-Montana border, and the Mud Lick Fire about 25 miles west of Salmon in the Panther Creek Drainage. 

Downed tree pile

IDFG worked with the U.S. Forest Service to relocate thousands of downed trees from the fire break to the Lemhi River for use on a large-scale restoration project on Eagle Valley Ranch.  This project is re-aligning the river channel, adding multiple side channels, expanding the floodplain, and adding large woody debris to increase habitat quality and quantity for Salmon and steelhead.  This project will span over the next few years, and will continue to have a high demand for large woody debris.  Hundreds of woody debris structures have already been put in place for this project, with many more to come as the project is completed.