New GIS Tool Helps Remove Barriers to Salmon Habitat Connectivity

Clean, cold water. Lush riparian vegetation. Gravels for spawning. These are some of the elements that create healthy habitat for salmon. The Upper Columbia region has some of the best in the Pacific Northwest. Unfortunately, not all of this habitat is within the salmon’s reach. Removing barriers such as culverts and dams is a top priority for salmon recovery goals, but there are thousands of barriers, limited resources to remove them, and a diverse group of stakeholders with issues to address. What everyone wants to know first is: how do we decide WHICH barriers to remove?

Instream barriers such as culverts like this can limit fish passage to available habitat.

Enter a New Tool for Fish Habitat Decision Making

In partnership with the Cascade Columbia Fisheries Enhancement Group, the Upper Columbia Salmon Recovery Board, the Upper Columbia Regional Technical Team (RTT), and a technical steering committee, Aspect created a GIS-based decision support tool that summarizes the overall quality of ecological conditions surrounding each instream barrier within the Wenatchee Basin. This custom spatial model provides insight into critical questions regarding barrier-removal priority:

  • Is there habitat available upstream from the barrier that salmon currently cannot access?

  • Is that available habitat of sufficient quality for salmon?

  • Is there known fish usage near the barrier already?

  • Are there barriers downstream blocking fish access?

This prioritization tool provides salmon-recovery stakeholders with a common approach to answer these questions. The variables under consideration at a barrier—upstream habitat quality, local stream temperature, connectivity to other barriers, etc.—each receive a score. Those scores are then added up to a total priority tier ranking for that barrier. By assessing each barrier through this scoring process, we’ve created an actionable apples-to-apples comparison of habitat benefits associated with barrier removal.

A preview of barrier removal ranking priority data.

A preview of barrier removal ranking priority data.

A Tier 1 ranking indicates the top priority for removal, indicating more biological benefit gained from a barrier’s removal. Tier 4 ranking is the lowest priority ranking, indicating little biological benefit gained from a barrier’s removal. UCSRB and the RTT use these categories to guide decisions on proposed project funding. The rankings are updated as available data sources improve.  Preview the results HERE. This tool will allow stakeholders to align and coordinate their barrier removal work towards the larger common goal of salmon-habitat connectivity within the Upper Columbia and throughout the state.

If interested in adapting this tool for your project and/or basin(s), contact Robyn Pepin for more information.