Columbia Lakes South Lake Dam

About Columbia Lakes South Lake Dam

The primary purpose of Columbia Lakes South Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Columbia Lakes Homeowners Associations (private). It impounds the Trib Palmer Creek near Millstadt Junction.

The dam stands 25 feet tall and stretches 245 feet across, creates a reservoir covering 9 acres, has a maximum storage capacity of 126 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1990, the structure is 36 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. An emergency action plan is in place for this dam. The most recent inspection on record was 11/14/2025.

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

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