Old Longs Mill Dam

About Old Longs Mill Dam

The primary purpose of Old Longs Mill Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Carol Siemion (private). It impounds the Coffee Creek.

The dam stands 20 feet tall and stretches 200 feet across, creates a reservoir covering 10 acres, has a maximum storage capacity of 81 acre-feet, and collects water from a drainage area of 7 square miles. Completed in 1930, the structure is well-established, with more than 75 years of service.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 01/09/2020.

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