Graham Lake Dam

About Graham Lake Dam

The primary purpose of Graham Lake 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 Black Bear Hydro Partners, Llc (private). It impounds the Union River near Ellsworth.

The dam stands 43 feet tall and stretches 630 feet across, creates a reservoir covering 10,300 acres, has a maximum storage capacity of 130,000 acre-feet, and collects water from a drainage area of 499 square miles. Completed in 1924, the structure is over a century 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 09/21/2022.

At 43 feet, this dam is taller than 89% of dams nationwide.

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 Maine dam safety program can provide more specific information about emergency planning for this structure.

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