National

Aquatic Barrier Inventory & Prioritization Tool

Aquatic Barrier Tool

Photo: Bureau of Land Management

Pacific Northwest Region

Pacific Northwest region map
Map of 8,861 inventoried dams and 37,410 road-related barriers likely to impact aquatic organisms in the Pacific Northwest region.

Includes 3 states with:

8,861 inventoried dams, including:

  • 334 that have been reconned for social feasibility of removal
  • 233 that have been removed or mitigated, gaining 19,866 miles of reconnected rivers and streams

683,026 or more potential road-related aquatic barriers, including:

  • 67,493 that have been assessed for impacts to aquatic organisms
  • 37,410 that are likely to impact aquatic organisms
  • 3,553 that have been removed or mitigated, gaining 15,832 miles of reconnected rivers and streams

Progress toward restoring aquatic connectivity:

year removed
show:miles gained|number removed
2024
7.7 miles
2023
868 miles*
2022
642 miles*
2021
1,330 miles*
2020
1,189 miles*
2010-2019
10,408 miles*
2000-2009
6,061 miles*
before 2000
12,797 miles*
unknown
2,395 miles*
dams
road-related barriers
* includes 316 dams and / or road-related barriers that could not be correctly located on the aquatic network or were otherwise excluded from the analysis; these contribute toward the count but not the miles gained.
Note: counts above may include both completed as well as active barrier removal or mitigation projects.
Explore how many dams or road-related barriers there are in a state, county, or watershed.
Explore dams and road-related barriers that have been removed or mitigated by state, county, or watershed.
Identify and rank dams or road-related barriers that reconnect the most high-quality aquatic networks.

Statistics by state:

Inventoried damsReconned damsAssessed road-related barriers
Idaho1,092243,117
Oregon4,3768817,634
Washington3,39322246,742
Total8,86133467,493

1,449 inventoried dams and 9,118 assessed road-related barriers were not analyzed because they could not be correctly located on the aquatic network or were otherwise excluded from the analysis. You can optionally include these in your download.

Note: These statistics are based on inventoried dams and road-related barriers. Because the inventory is incomplete in many areas, areas with a high number of dams may simply represent areas that have a more complete inventory.

Data Sources

Records describing dams and road-related barriers within Idaho include those maintained by the Idaho Department of Fish and Game.
Records describing dams and road-related barriers within Oregon include those maintained by the Oregon Department of Fish and Wildlife.
Records describing dams and road-related barriers within Washington State include those maintained by the Washington State Department of Fish and Wildlife, Fish Passage Division. For more information about specific structures, please visit the fish passage web map.

You can help!

You can help improve the inventory You can help improve the inventory by sharing data, assisting with field reconnaissance to evaluate the impact of aquatic barriers, or even by reporting issues with the inventory data in this tool.

Contact us to learn more about how you can help improve aquatic connectivity in the Pacific Northwest region.

Chum salmon, Allison Springs, WA
Photo: Chum salmon, Allison Springs, WA. Roger Tabor / U.S. Fish and Wildlife Service.