Middle Lemhi River – Henry Reach

Salmonid Habitat Restoration and Acquisition

Instream Habitat Riparian Habitat
Project ID007 18 SA
Recovery DomainsInterior Columbia
Start Date12/01/2018
End Date12/31/2021
Year2018
StatusOngoing
Last Edited10/21/2021
 
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Description    


The Middle Lemhi River – Henry Reach project will design and construct habitat treatments on the Lemhi River. This reach has a reduced floodplain interaction with the river, a single river channel, and no woody structure or lateral habitat. The riparian areas adjacent to the river are relatively intact with a functional understory of willows scattered among mature cottonwood communities. This project will expand the current limited floodplain into the existing riparian area by 11.75 acres, while creating a mile of lateral side channel habitat containing multiple complex large woody debris structures within a 0.65 mile segment of the Lemhi. Seventeen pools will be created through channel reconfiguration and connectivity, and ten pools are expected to be created through channel structure placement, for a total of 27 pools. Forty structures consisting of anchored and unanchored logs, logjams, and stumps with rootwads will be placed in a 0.50 mile segment (one acre of streambed). Logs and vegetation will be used to stabilize the streambank for 0.20 mile. Riparian zone restoration and protection will occur on 1.25 mile (1.2 acre) through the planting of native willows and cottonwoods.

This project received an amendment to increase funds and the project scope in November 2019. The database has been revised to reflect the increase in funds and the additional metrics. Note that this project is multi-year funded from FY16 and FY18.

Project Benefit    


The goal of the Middle Lemhi River Henry Reach is to expand the property into more of a natural floodplain while restoring natural river processes and function. Project objectives include extending the existing river length through increasing sinuosity, developing complexity in the existing river channel, development of lateral side channels, and riparian zone restoration and protection.

Rehabilitation treatments prescribed for the Henry Reach will contribute substantially to improving freshwater productivity of Chinook salmon and steelhead in the Lemhi River. The project is located just downstream of the two primary Chinook salmon production areas. 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 direction addresses these life stages by developing side channels, deepening the river depth and reducing current velocities, and installing ample large woody debris structures that provide immediate fish habitat.

Accomplishments

Metric Completed Originally
Proposed
Instream Habitat
  Stream Miles Treated 1.00
Riparian Habitat
  Stream Miles Treated 1.25
  Acres Treated 1.2

Funding Details

SourceFunds
PCSRF$475,233
Other$187,200
Report Total:$662,433


Project Map



Worksites

Lemhi Henry Reach    


  • Worksite Identifier: Lemhi Henry Reach
  • Start Date: 12/01/2018
  • End Date: 12/31/2021
Area Description
Lemhi RIver

Location Information

  • Basin: Salmon
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Idaho
  • Recovery Domain: Interior Columbia
  • Latitude: 44.898049
  • Longitude: -113.625949

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 .00
    •      . . C.0.b Length of stream treated/protected
    •      . . 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
      •      . . . . C.4.b Total length of instream habitat treated
      •      . . . . 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
        •      . . . . . . C.4.c.4 Miles of off-channel stream created through channel reconfiguration and connectivity
        •      . . . . . . C.4.c.5 Acres of off-channel or floodplain connected through channel reconfiguration and connectivity
        •      . . . . . . C.4.c.6 Instream pools created/added through channel reconfiguration and connectivity
      •      . . . . 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
        •      . . . . . . C.4.d.4 Acres of streambed treated through channel structure placement
        •      . . . . . . C.4.d.5 Pools expected to be created through channel structure placement
        •      . . . . . . 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
      •      . . . . 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
      •      . . C.5 Riparian Habitat ProjectY (Y/N)
        •      . . . . C.5.a Riparian Habitat Funding
        •      . . . . C.5.b.1 Total riparian miles streambank treated
        •      . . . . C.5.b.2 Total Riparian Acres Treated
        •      . . . . C.5.c.1 Riparian plantingY (Y/N)
          •      . . . . . . C.5.c.2
            Species of plants planted in riparian
          •      . . . . . . C.5.c.3 Acres planted in riparian
          •      . . . . . . C.5.c.4 Miles of streambank treated with riparian planting