Middle Lemhi River – Hayden Reach Phase 1

Salmonid Habitat Restoration and Acquisition

Instream Habitat Riparian Habitat
Project ID006 20 SA
Recovery DomainsSnake River
Start Date12/09/2020
End Date03/31/2024
Year2020
StatusCompleted
Last Edited04/09/2024
 
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Description    


The Lemhi Soil and Water Conservation District (LSWCD) designed and constructed habitat treatments on a 0.33 mile segment of the Lemhi River located near the confluence of Hayden Creek and the Lemhi River. Pre-project habitat conditions included a straightened channelized river segment confined by State Highway 28 that contained no instream woody structure, no side channels or other lateral habitat, a disengaged floodplain, and limited riparian vegetation.



The project increased habitat capacity for juvenile salmon and steelhead by constructing a new alignment for the Lemhi River (including pool excavation) to increase sinuosity, raising the surface water elevation of the river by installing engineered riffles (unanchored boulders) to improve river and floodplain function, adding large wood instream to provide channel structure, roughness, and complexity, floodplain grading to increase lateral floodplain connectivity, streambank stabilization, and grass seeding and plantings of native herbaceous and woody species to rehabilitate the riparian zone.



This was Phase 1 of a 2-Phase project focusing on habitat rehabilitation along approximately 0.70 miles of the Lemhi River. Phase 1 was implemented under this contract, with treatments constructed along 0.33 miles of the Lemhi River. This project received amendments to extend and to decrease awarded funds. Due to an icing event on a restoration project downstream, this project along with several others were reviewed by an interagency flood risk team. It was determined that this project had a significant chance of having ice problems like those that had occurred downstream, and some of the proposed project actions were scaled back. It is likely this project will undergo a redesign and some sort of adaptive management under Phase 2. Phase 2 will be completed under PCSRF project 017 21 SA, being sponsored by Idaho Fish and Game.

Project Benefit    


Developing a large portion of this property into more of a natural floodplain while restoring natural river processes and function will directly increase habitat capacity for juvenile life stages of salmon and steelhead. Improving the current condition by increasing river sinuosity, developing habitat complexity in the form of woody debris structures, constructing side channels, and riparian zone restoration will result in improved survival for all freshwater juvenile life stages. Furthermore, the magnitude of these affects will be substantial since project is located at the downstream end of the Lemhi primary Chinook salmon production area. Immediately upstream of the project site, the Lemhi River is a heavily incised single thread channel with no functional summer rearing or wintering habitat. As such, the project is ideally located to function as a “catcher’s mitt”, providing much needed habitat for rearing parr that were displaced by spring high flows from upstream production areas, and for pre-smolts moving out of the production areas in the fall in preparation for overwintering. The conceptual design directly addresses these life stages by developing instream habitat and floodplain diversity.

Accomplishments

Metric Completed Originally
Proposed
Instream Habitat
  Stream Miles Treated .33 .70
Riparian Habitat
  Stream Miles Treated .04 1.40
  Acres Treated .7 1.2

Funding Details

SourceFunds
PCSRF$313,712
Other$549,596
Report Total:$863,308


Project Map



Worksites

WS1- Lemhi River Hayden P1    


  • Worksite Identifier: WS1- Lemhi River Hayden P1
  • Start Date: 12/09/2020
  • End Date: 12/31/2020
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Salmon (170602)
  • Subbasin: Lemhi (17060204)
  • Watershed: Upper Lemhi River (1706020405)
  • Subwatershed: Zeph Creek-Lemhi River (170602040510)
  • State: Idaho
  • Recovery Domain: Snake River
  • Latitude: 44.861376
  • Longitude: -113.62265

ESU

  • Snake River Basin Steelhead DPS
  • Snake River Spring/Summer-run Chinook Salmon ESU

Map

Photos

Metrics

Metrics
  • C.0 Salmonid Habitat Restoration and AcquisitionY (Y/N)
    •      . . C.0.a Habitat restoration and acquisition funding 863,308.00
    •      . . C.0.b Length of stream treated/protected .33
    •      . . C.0.c
      Project identified in a Plan or Watershed Assessment
    •      . . C.0.d.1 Project Monitoring (LOV)
    •      . . C.0.d.2 Monitoring Location (LOV)
    •      . . C.4 Instream Habitat ProjectY (Y/N)
      •      . . . . C.4.a Instream Habitat Funding 854,009.00
      •      . . . . C.4.b Total length of instream habitat treated .33
      •      . . . . C.4.c.1 Channel reconfiguration and connectivityY (Y/N)
        •      . . . . . . C.4.c.2 Type of change to channel configuration and connectivity (LOV)
        •      . . . . . . C.4.c.3 Miles of stream treated for channel reconfiguration and connectivity .33
        •      . . . . . . C.4.c.4 Miles of off-channel stream created through channel reconfiguration and connectivity .10
        •      . . . . . . C.4.c.5 Acres of off-channel or floodplain connected through channel reconfiguration and connectivity 1.9
        •      . . . . . . C.4.c.6 Instream pools created/added through channel reconfiguration and connectivity 14
      •      . . . . C.4.d.1 Channel structure placementY (Y/N)
        •      . . . . . . C.4.d.2 Material used for channel structure (LOV)
        •      . . . . . . C.4.d.3 Miles of stream treated through channel structure placement .10
        •      . . . . . . C.4.d.4 Acres of streambed treated through channel structure placement .3
        •      . . . . . . C.4.d.5 Pools expected to be created through channel structure placement 11
        •      . . . . . . C.4.d.6 Yards of average stream-width at mid-point of channel structure placement project (Yards)
        •      . . . . . . C.4.d.7 Number of structures placed in channel 23
      •      . . . . C.4.e.1 Streambank stabilization Y (Y/N)
        •      . . . . . . C.4.e.2 Material Used For Streambank Stabilization (LOV)
        •      . . . . . . C.4.e.3 Miles of streambank stabilized .04
      •      . . C.5 Riparian Habitat ProjectY (Y/N)
        •      . . . . C.5.a Riparian Habitat Funding 9,299.00
        •      . . . . C.5.b.1 Total riparian miles streambank treated .04
        •      . . . . C.5.b.2 Total Riparian Acres Treated .7
        •      . . . . C.5.c.1 Riparian plantingY (Y/N)
          •      . . . . . . C.5.c.2
            Species of plants planted in riparian
            Salix spp
          •      . . . . . . C.5.c.3 Acres planted in riparian .7
          •      . . . . . . C.5.c.4 Miles of streambank treated with riparian planting .04