Lower Twin Lake

About Lower Twin Lake

The primary purpose of Lower Twin Lake is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Fort Jackson (federal). It impounds the Mill Creek near Columbia.

The dam stands 21 feet tall and stretches 530 feet across, creates a reservoir covering 25 acres, has a maximum storage capacity of 650 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.

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 03/24/2021.

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

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