Great Hill Reservior Dam

About Great Hill Reservior Dam

The primary purpose of Great Hill Reservior Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town Of Seymour (local government). It impounds the Fourmile Brook near Shelton.

The dam stands 41 feet tall and stretches 165 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 378 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1909, 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 09/18/2021.

At 41 feet, this dam is taller than 88% 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 Connecticut dam safety program can provide more specific information about emergency planning for this structure.

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