Timothy Lake

About Timothy Lake

The primary purpose of Timothy Lake 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 Portland General Electric Company (private). It impounds the Oak Grove River near Estacada, Or.

The dam stands 100 feet tall and stretches 740 feet across, creates a reservoir covering 1,430 acres, has a maximum storage capacity of 69,000 acre-feet, and collects water from a drainage area of 54 square miles. Completed in 1956, 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 09/20/2022.

At 100 feet, this dam is taller than 98% 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.

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