South Fork Walla Walla River Floodplain Enhancement II

Salmonid Habitat Restoration and Acquisition

Instream Habitat
Project ID22-Umat-05
Recovery DomainsMiddle Columbia River
Start Date07/01/2023
End Date08/31/2023
Year2022
StatusCompleted
Last Edited02/27/2024
 
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Description    


A large flood event that occurred in February 2020 caused changes to several previously completed floodplain and fish habitat restoration projects in the South Fork Walla Walla River. These changes have triggered adaptive management as defined in the Monitoring and Adaptive Management Plans developed for those previously completed projects.


This project proposed a new large wood structure and selective removal of flood debris, primarily woody material, from the existing wood structure. The new structure was placed on the right bank point bar just upstream of the channel split. The intention of the structure is to help direct water towards the side channel and provide additional roughness and habitat improvements during high flow events. PCSRF funds were used to purchase materials and construct the structure designed to maintain full functionality of the 2018 Project.


5 engineered log structures were built at the upstream end of the SFWW RM 5-6 floodplain restoration project to enhance in-stream habitat, maintain floodplain function, and mitigate unintended impacts on infrastructure. Each structure was composed of 6 logs with rootwads and 5 vertical members. The array of log structures is intended to encourage the thalweg of the South Fork Walla Walla River away from the county road, scour pools and provide juvenile and adult salmonid spawning and rearing habitat, and encourage sedimentation on the river right bank.


This adaptive management project was completed between July 15 and August 4. A contractor was solicited and selected to provide materials, equipment, and labor to install 5 large wood structures on the previously-completed South Fork Walla Walla River RM 5-6 floodplain restoration project. This adapative management action is taken in accordance with the site-specific monitoring and adaptive management plan and is intended to enhance instream fish habitat while maintaining floodplain functionality and mitigating unintended impacts on the adjacent county road. The project was constructed as planned and without incident.


Note: Projects 22-Umat-01 and 22-Umat-05 addressed the same effort with metrics to be allocated between the two (22-Umat-01 is accomplished with IIJA funding while 22-Umat-05 is with base funding.)

Project Benefit    


Adding the large wood structures will continue the work from the previous 2015 and 2018 projects. It will continue to provide connectivity to the floodplain and offer a wide variety of habitats to native fishes. It will add roughness during high-flow events. The large wood debris will provide pooling habitat for different fishes. It will allow sediments to deposit behind the structures and encourage the thalweg away from critical infrastructure adjacent to the 2015 Project.

Accomplishments

Metric Completed Originally
Proposed
Instream Habitat
  Stream Miles Treated .05 .03

Funding Details

SourceFunds
PCSRF$68,368
Other$72,777
Report Total:$141,145


Project Map



Worksites

South Fork Walla Walla River RM 5.0 – 6.0    


  • Worksite Identifier: South Fork Walla Walla River RM 5.0 – 6.0
  • Start Date: 07/01/2023
  • End Date: 08/31/2023
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Middle Columbia (170701)
  • Subbasin: Walla Walla (17070102)
  • Watershed: Upper Walla Walla River (1707010201)
  • Subwatershed: Lower South Fork Walla Walla River (170701020103)
  • State: Oregon
  • Recovery Domain: Middle Columbia River
  • Latitude: 45.8527
  • Longitude: -118.2133

ESU

  • Middle Columbia River Steelhead DPS

Map

Photos

Metrics

Metrics
  • C.0 Salmonid Habitat Restoration and AcquisitionY (Y/N)
    •      . . C.0.a Habitat restoration and acquisition funding 141,145.00
    •      . . C.0.b Length of stream treated/protected .05
    •      . . C.0.c
      Project identified in a Plan or Watershed Assessment
      Middle Columbia River Summer Steelhead Distinct Population Segment ESA Recovery Plan (NMFS 2009), Walla Walla Subbasin Plan (NPCC 2004), Revised Recovery Plan for the Coterminous United States Population of Bull Trout (USFWS 2015)
    •      . . 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 141,145.00
      •      . . . . C.4.b Total length of instream habitat treated .05
      •      . . . . 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 .05
        •      . . . . . . C.4.d.4 Acres of streambed treated through channel structure placement .1
        •      . . . . . . C.4.d.5 Pools expected to be created through channel structure placement 5
        •      . . . . . . C.4.d.6 Yards of average stream-width at mid-point of channel structure placement project10 (Yards)
        •      . . . . . . C.4.d.7 Number of structures placed in channel 5