Middle Lemhi River – Henry Reach, Phase 2

Salmonid Habitat Restoration and Acquisition

Instream Habitat Riparian Habitat
Project ID007 21 SA
Recovery DomainsInterior Columbia
Start Date12/09/2021
End Date10/31/2023
Year2021
StatusNew
Last Edited03/14/2022
 
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Description    


The Middle Lemhi River – Henry Reach, Phase 2 will design and construct habitat treatments prescribed for the second phase of the Henry Reach project. The Henry Reach is a 0.65 mile segment of the Lemhi River located approximately 2 miles downstream of the confluence of Hayden Creek and the Lemhi River. Phase 1 addressed the previously degraded habitat condition by realigning the mainstem river and constructing side channels containing multiple complex large woody debris structures, and adjusting the river and floodplain grade to increase their interaction. Phase 2 will augment Phase 1 actions by constructing a series of additional lateral habitats while further improving instream structure and floodplain interaction. Phase 2 will spatially expand the current floodplain while improving channel complexity and hydraulic diversity. Existing levees will be removed. Specific habitat treatments will include constructing relic beaver dam complexes (found under ‘other engineered structures’ in metrics) to increase off channel habitat, installing more complex instream habitat in the form of large woody debris, creating instream pools, and further raising river surface water to further increase floodplain interaction. Riparian zone plantings of willow and cottonwood are prescribed to accelerate growth of riparian vegetation in disturbed areas, along with seeding.

Project Benefit    


Further development of the relatively large active floodplain created during Phase 1 of the Henry Reach project will increase habitat capacity for critical juvenile life stages of Chinook salmon and steelhead. In the Lemhi watershed, habitat condition has been altered to the extent that the capacity of the system is unable to support critical life stages of juvenile fish. In most areas, water velocities are high, and slow water habitats that are optimal for fish rearing and growth are non-existent. Project actions will address this condition and provide habitat complexity for key juvenile life stages that is currently limiting recovery of ESA listed fish throughout the Lemhi basin.



Increased habitat capacity is expected to improve Chinook salmon and steelhead freshwater productivity throughout the Lemhi watershed. The Henry Reach is located within a segment of the Lemhi River that contains some of the highest densities of juvenile salmon (IDFG unpublished data). Any increase in hydraulic and structural habitat diversity in this area is expected to result in a proportionally higher increase in fish abundance and survival. As such, more juveniles will leave the Lemhi River sub-basin in better condition per each adult that enters the system to spawn.

Accomplishments

Metric Completed Originally
Proposed
Instream Habitat
  Stream Miles Treated .20
Riparian Habitat
  Stream Miles Treated .20
  Acres Treated 1.0

Funding Details

SourceFunds
PCSRF$198,665
Other$69,901
Report Total:$268,566


Project Map



Worksites

Lemhi Henry Reach    


  • Worksite Identifier: Lemhi Henry Reach
  • Start Date: 01/01/2022
  • End Date: 10/31/2023
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Salmon
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Idaho
  • Recovery Domain: Interior Columbia
  • Latitude: 44.900565
  • Longitude: -113.627316

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.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.5 Pools expected to be created through channel structure placement
        •      . . . . . . C.4.d.7 Number of structures placed in channel
      •      . . 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