Assessment of Multi-Thread Reference Streams in the Upper Salmon River Basin

Upper Salmon River Reference Reach Assessment (click here to read full report)

Authors: Tim Hanrahan (Rio ASE), Rob Richardson (Rio ASE), Sam Box (Rio ASE), Bryce Oldemeyer (Mount Hood Environmental), Tulley Mackey (Mount Hood Environmental), Mark Roes (Mount Hood Environmental)

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Some of the highest quality habitat in the central Idaho is found in tributary streams within the Middle Fork Salmon River (MFSR) watershed. In particular, sections of Marsh Creek, Bear Valley Creek, and Elk Creek comprise high-quality habitat and geomorphic complexity, including multi-thread channels. The MFSR watershed contains some of the most important ecological areas for salmon and steelhead in central Idaho and is managed as a designated wild anadromous fish sanctuary, where the production potential of the watershed and the ability of salmon and steelhead to respond to the quality and quantity of available natal habitat have largely unaltered. Natural physical and ecological processes in the MFSR watershed function relatively unimpeded by humans, resulting in high-quality and diverse natal fish habitats. The habitat found in these MFSR tributaries provides valuable insight that can be used to inform restoration strategies and designs within priority project development areas of the Upper Salmon River Basin (USRB).

The overall goal of the information provided in the assessment report is to improve the science and engineering practice of multi-thread channel stream restoration design in the USRB by evaluating reference reaches exhibiting relatively high-quality geomorphic and biological characteristics. Advancing our understanding of multi-thread channel formation and evolution, and the associated fish habitat characteristics, within each reference reach is intended to facilitate future secondary channel project development and restoration design.

This report includes a summary of the environmental setting for the reference reaches within Marsh Creek, Bear Valley Creek, and Elk Creek, including a description of the secondary channel types located in those reference reaches. Summaries of the reference reach geomorphic and biological/habitat characteristics are provided in the report, with additional details described in appendices.

Eagle Valley Ranch at High Water

We recently collected some pretty cool orthographic imagery of our Eagle Valley Ranch project on the Lemhi River near Salmon, Idaho. The drone imagery below shows the project in July 2019, prior to any construction compared to last week, May 2023, when the river was at high water. Use the slider to compare the two and see the progress on the project. There are four construction phases of this project, and we are currently simultaneously wrapping up Phase 2 while mid-construction on Phase 3.