Eighteenmile Creek Railroad Grade Culvert to Bridge-PCSRF

Salmonid Habitat Restoration and Acquisition

Fish Passage Improvement
Project ID016 11 SA
Recovery DomainsInterior Columbia
Start Date07/01/2015
End Date08/21/2015
Last Edited10/21/2021
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Two undersized, side-by-side corrugated metal culverts used to convey Eighteenmile Creek underneath a private road were replaced with a 45 span by 16 wide prefabricated modular steel bridge to provide an additional 3.2 miles of unimpaired fish passage for all life stages of ESA-listed anadromous and resident fish species. This project addressed mechanical injury and habitat barriers for both steelhead and Chinook salmon by eliminating the current physical barrier, as well as restoring a more natural condition to the channel at this location.

A deviation to the project proposal was the initial report that removal of the side-side-culverts on Eighteenmile Creek would provide an additional 1.2 miles of fish access upstream to the next barrier, the Hawley/Eighteenmile Creek Intercept. However, due to removal of the intercept as part of a separate project, also in August 2015, the Eighteenmile Creek Bridge actually opened 3.2 miles of habitat access.
Another deviation was the end date for the project completion. Originally the end date was scheduled for November 15, 2015, but actually closed on August 21, 2015.

The project sponsor indicates that they will treat the project site for noxious weeds in the fall of 2015 and hydro-seed the site in the spring of 2016, as part of ongoing actions related to this project.

Project Benefit    

The elimination of the current physical barrier (two culverts) at the Old Railroad Grade bridge, will allow passage for all life stages of ESA-listed salmonids and restore a more natural condition to the Eighteenmile Creek channel. This project is part of a plan to reconnect Hawley Creek, which will be implemented over the next five years to eliminate remaining barriers and increase instream flows on Hawley Creek. Removal of this fish passage barrier will provide an additional 1.2 miles of access upstream.


Metric Completed Originally
Fish Passage
  Barriers Removed
  Miles Opened 3.20 1.20

Funding Details

Report Total:$91,177

Project Map


Eighteenmile Creek    

  • Worksite Identifier: Eighteenmile Creek
  • Start Date: 07/01/2015
  • End Date: 08/21/2015
Area Description
Salmon Subbasin, Lemhi 4th field HUC-17060204

Location Information

  • Basin: Salmon
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Idaho
  • Recovery Domain: Interior Columbia
  • Latitude: 44.672025
  • Longitude: -113.331929


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




  • C.0 Salmonid Habitat Restoration and AcquisitionY (Y/N)
    •      . . C.0.a Habitat restoration and acquisition funding 91,177.00
    •      . . C.0.b Length of stream treated/protected .01
    •      . . C.0.c
      Project identified in a Plan or Watershed Assessment
      Ecovista, 2004, Salmon Subbasin Management Plan, Northwest Power and Conservation Council, Portland, OR
    •      . . 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 91,177.00
      •      . . . . C.2.b.1 Length of stream made accessible 3.20
      •      . . . . C.2.b.3 Type of blockage/barrier (LOV)
      •      . . . . C.2.b.4 Number of blockages/impediments/barriers impeding passage 1
      •      . . . . C.2.g.1 Bridge installed or improved at road stream crossingY (Y/N)
        •      . . . . . . C.2.g.2 Number of bridges installed or improved/upgraded 1
        •      . . . . . . C.2.g.3 Miles of stream made accessible by bridge installation or improvement/upgrade 3.20