VULNERABILITY ASSESSMENTS

​Vulnerability assessments [1] itemize and inspect all hydropower facility structures and components that come into contact with raw water, and make an informed judgment on the degree to which dreissenid mussels will impair the performance of the structures and components.[2]

 

A facility assessment process usually requires considerable time for planning and coordination, background research, site visits, evaluation of data and preparation of a report.[3] It is likely that a team approach with two or three people is most effective at carrying out the assessment with at least one person with operational knowledge/experience of the specific facility. The assessment team lead should become familiar with general mussel characteristics and behavior or possibly have a support person familiar with mussels as part of the assessment team.

 

The specific risks and problems that a particular facility will have with the dreissenids will depend on:

• The size of the dreissenid population in the area – actual/anticipated.

• How the raw water gets into the facility.

• Any processes to treat or transform the water for various facility applications.

• The routing of all piping branches and location of components and equipment, including materials of construction.

• The operating envelope of the various water systems (such as maximum and minimum flow rates, frequency of operation, temperature ranges).

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Preparing for Invasive Mussels: Vulnerability Assessment Guide for Raw Water Infrastructure (Claudi and Littley 2024).

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[1] U.S. Department of the Interior Bureau of Reclamation, May 2009, Facility Vulnerability Assessment Template, Invasive Quagga and Zebra Mussels. Prepared for Reclamation by: RNT Consulting Inc., 823 County Road 35, Picton, Ontario, Canada K0K 2T0, 26pp.

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[2] Prescott, T. Vulnerability Assessment of Zebra and Quagga Mussels on Facilities from Intake to Discharge. RNT Consulting, Inc. (PowerPoint Presentation).

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[3] U.S. Department of the Interior Bureau of Reclamation, May 2009, Facility Vulnerability Assessment Template, Invasive Quagga and Zebra Mussels. Prepared for Reclamation by: RNT Consulting Inc., 823 County Road 35, Picton, Ontario, Canada K0K 2T0, 26pp.

 

Columbia River Basin Vulnerability Assessment Team

Lisa DeBruyckere, Creative Resource Strategies, LLC (Coordinator)

Leska Fore, Seattle City Light

Serina Swanson, FortisBC

Meaghan Rupprecht, BC Hydro

Laura Hertz, USBR

Stephen Phillips, PSMFC

Michael Stephenson, Idaho Power

Michael Hounjet, Columbia Power

Wendy Horan, Columbia Basin Trust

TBD, Avista

TBD, USACE

TBD, Douglas County PUD

TBD, EWEB

 

Status of Vulnerability Assessments in the CRB (updated January 2026)
 

The map and list below illustrates vulnerability assessments that have been completed on hydropower facilities in the CRB (green pushpins) and vulnerability assessments planned for completion (yellow stickpins). 

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Columbia River

Bonneville Dam (US Army Corps of Engineers)

Dalles Dam (US Army Corps of Engineers)

John Day Dam (US Army Corps of Engineers)

McNary Dam (US Army Corps of Engineers)

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Washington

Banks Lake (Dry Falls and North Dams) (US BOR)

Boundary Dam (Seattle City Light)

Chief Joseph Dam (US Army Corps of Engineers)

Dworshak Dam (US Army Corps of Engineers)

Grand Coulee Dam (US Bureau of Reclamation)

Howard Hanson (US Army Corps of Engineers)

Ice Harbor Dam (US Army Corps of Engineers)

Lake Chelan (Chelan PUD)

Lower Monumental Dam (US Army Corps of Engineers)

Little Goose Dam (US Army Corps of Engineers)

Lower Granite Dam (US Army Corps of Engineers)

Mud Mountain (US Army Corps of Engineers)

Skagit River Hydroelectric Project (Seattle City Light)

Rock Island (Chelan PUD)

Rocky Reach (Chelan PUD)

Roza (Bureau of Reclamation)

 

Oregon

Bowman Dam (Bureau of Reclamation)

Owyhee Dam (Bureau of Reclamation)

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​Idaho

Albeni Falls Dam (US Army Corps of Engineers)

American Falls (Bureau of Reclamation)

Anderson Ranch (Idaho Power)

Arrowrock Dam (Bureau of Reclamation)

Black Canyon (Bureau of Reclamation)

Bliss (Idaho Power)

Brownlee Dam (Idaho Power)

Clear Lake (Idaho Power)

CJ Strike (Idaho Power)

Cascade Dam (Bureau of Reclamation)

Hells Canyon (Idaho Power)

Libby Dam (US Army Corps of Engineers)

Lower Malad (Idaho Power)

Lower Salmon Falls (Idaho Power)

Milner Dam (Idaho Power)

Oxbow Dam (Idaho Power)

Palisades Dam (Bureau of Reclamation)

Ririe Dam (Bureau of Reclamation)

Shoshone Falls (Idaho Power)

Swan Falls (Idaho Power)

​Thousand Springs (Idaho Power)

Twin Falls (Idaho Power)

Upper Malad (Idaho Power)

Upper Salmon Falls (Idaho Power)

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Wyoming

Jackson Lake Dam (Bureau of Reclamation)

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British Columbia

Arrow Lakes Generating Station (BC Hydro)

Brilliant Expansion (Columbia Power Corp)

Corra Linn Dam (Fortis BC)

Hugh Keenleyside Dam (BC Hydro)

Waneta Dam (BC Hydro)

Waneta Expansion (BC Hydro)