Big Cliff Dam

About Big Cliff Dam

The primary purpose of Big Cliff 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 - Portland District (federal). It impounds the North Santiam River near Mill City.

The dam stands 172 feet tall and stretches 280 feet across, creates a reservoir covering 141 acres, has a maximum storage capacity of 5,930 acre-feet, and collects water from a drainage area of 452 square miles. Completed in 1954, 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 05/10/2021.

At 172 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 Oregon dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.