Nursery Bridge Reach Phase II Fish Passage and In-stream Habitat Enhancement II

Salmonid Habitat Restoration and Acquisition

Fish Passage Improvement Instream Habitat
Project ID20-Umat-02
Recovery DomainsInterior Columbia
Start Date05/01/2022
End Date12/31/2023
Last Edited04/13/2022
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The Nursery Bridge Reach of the Walla Walla River is one of two major fish passage bottlenecks in the Walla Walla subbasin that currently impact recovery of Middle Columbia River summer steelhead, Columbia River bull trout, and spring Chinook salmon. Over a century of impacts from urbanization, channelization, and agriculture has resulted in extreme constriction of the Walla Walla River, reducing its nearly 5-mile wide active alluvial fan to the current floodprone width of approximately 300 feet. The Nursery Bridge Reach is a highly altered portion of the Walla Walla River near Milton-Freewater, Oregon, that includes several road and railroad crossings, a significant point of diversion for senior water users of the Walla Walla River Irrigation District (WWRID), and an extensive US Army Corps of Engineers-authorized flood risk management project consisting of a levee system and a large grade control structure with two associated fishways.

The Nursery Bridge Phase II Fish Passage and In-stream Enhancement Project (hereafter “the Project”) is intended to address the factors identified above that impact ESA-listed salmonids. The objective of this project is to provide stable fish passage connectivity to the Eastside Fishway at the GCS, reliable inflows to the WWRID diversion, and habitat for salmonids over a range of flows. PCSRF funds for this project will be spent on subcontract fees for constructing the roughened riffle structure to enhance fish passage at the GCS.

This project is intended to enhance fish passage and increase instream habitat for ESA-listed salmonids in an approximately 3,075-foot reach in the vicinity of Nursery Bridge in Milton-Freewater, Oregon. The CTUIR and project partners are proposing to enhance fish passage at the Nursery Bridge GCS by creating an 18-inch deep by 20-foot wide notch in the crest of the GCS near the entrance of the Eastside Fishway, and constructing an approximately 350-foot long roughened riffle with low flow channel and armored bar to maintain channel alignment with the GCS notch. The grade-controlled low flow channel is designed to maintain water surface elevations to reliably deliver water to the entrance to the Eastside Fishway and the WWRID point of diversion with minimal annual maintenance and disturbance to the channel.

Upstream of the GCS, the CTUIR is proposing to excavate 3,258 feet of side channel to reinitiate perennial flow to provide off-channel rearing habitat for ESA-listed salmonids at a variety of flows. 34 engineered log structures, including bar apex jams, bank habitat jams, and log revetments, will be placed in the approximately ½ mile above the GCS. The CTUIR is proposing installing 908 pieces of large wood with rootwads in this treatment that will provide in-channel complexity for rearing salmonids. Construction oversight will be conducted by CTUIR staff and staff from the design firms as implementation monitoring to ensure that the project is constructed as designed. Implementation monitoring will consist of topographic oversight using survey equipment to ensure construction elevations and slopes are constructed properly, as well as monitoring the sizing of large wood and rock materials being installed to ensure features are constructed per the specifications in the design. CTUIR and agents will also monitor construction methods. The project design is currently at 60% completion. It is anticipated that the design will be completed by summer 2021. Implementation is anticipated in summer/fall 2022.

Project Benefit    

Limiting factors for Middle Columbia River summer steelhead in the Nursery Bridge Reach include: blocked and impaired passage, degraded floodplain connectivity and function, degraded water temperature, altered sediment routing, and hydrologic alterations (NMFS 2009). Due to the infrastructure constraints in the reach, it may not be feasible to address all of the identified limiting factors; however, this project intends to address fish passage and floodplain connectivity and function in the reach.

The proposed GCS notch and low flow channel in the immediate vicinity of the GCS will create a more stable channel adjacent to the entrance to the Eastside Fishway. Providing reliable fish passage at the Nursery Bridge GCS allows access to over 70 miles of some of the highest quality spawning and rearing habitat in the Walla Walla Subbasin, located within the North and South Forks of the Walla Walla River and Couse Creek. This project would increase the efficacy of the Eastside Fishway at the GCS and allow volitional passage for all life stages of ESA-listed salmonids to meet ODFW and NMFS fish passage requirements.

Degraded floodplain connectivity and function will also be addressed as a result of this project. Floodplain connectivity will be enhanced by reinitiating 3,258 feet of side channel which will increase floodplain activation at lower flows to provide off channel summer rearing habitat and low velocity refugia for winter rearing salmonids on the floodplain. Large wood additions will also increase complexity and functionality of the floodplain for juvenile salmonid rearing.

Due to the constrained nature of the flood control project in the Nursery Bridge reach, this project will likely not address the remaining limiting factors of degraded water temperature, altered sediment routing, and hydrologic alteration. These factors will be addressed in future phases of the Nursery Bridge reach project.

Post-implementation action effectiveness monitoring is not specifically proposed for this project. The lack of project specific funding available for monitoring and the lack of applicability of this project within larger regional monitoring efforts due to its location within a confined flood control project makes the logistics of effectiveness monitoring of the project difficult. However, fish passage at the site is monitored by CTUIR Fish Passage Operations staff at the Nursery Bridge east and west fishways by virtue of monitoring ladder operations.


Metric Completed Originally
Instream Habitat
  Stream Miles Treated .75
Fish Passage
  Barriers Removed
  Miles Opened 70.61

Funding Details

Report Total:$4,445,000

Project Map


Nursery Bridge Reach    

  • Worksite Identifier: Nursery Bridge Reach
  • Start Date: 05/01/2022
  • End Date: 12/31/2022
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Middle Columbia
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Oregon
  • Recovery Domain: Interior Columbia
  • Latitude: 45.94517
  • Longitude: -118.384563


  • Middle Columbia River Steelhead DPS




  • 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.2 Fish Passage ImprovementY (Y/N)
      •      . . . . C.2.a Fish Passage Funding
      •      . . . . C.2.b.1 Length of stream made accessible
      •      . . . . C.2.b.2 Square miles of streambed made accessible (Square miles)
      •      . . . . C.2.b.3 Type of blockage/barrier (LOV)
      •      . . . . C.2.b.4 Number of blockages/impediments/barriers impeding passage
      •      . . . . C.2.e.1 Fish ladder installed/improvedY (Y/N)
        •      . . . . . . C.2.e.2 Number of fish ladders installed/improved
      •      . . 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