Chief Joseph Dam

About Chief Joseph Dam

The primary purpose of Chief Joseph Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Usace - Seattle District (federal). It impounds the Columbia River near Bridgeport.

The dam stands 230 feet tall and stretches 4,300 feet across, creates a reservoir covering 8,400 acres, has a maximum storage capacity of 593,000 acre-feet, and collects water from a drainage area of 75,400 square miles. Completed in 1955, the structure is well into its service life at over 50 years old.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 06/21/2022.

At 230 feet, this dam is taller than 99% of all dams in the United States.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Washington dam safety program can provide more specific information about emergency planning for this structure.

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