Little Grassy Dam

About Little Grassy Dam

The primary purpose of Little Grassy Dam is fish and wildlife pond. The dam creates habitat for fish and wildlife, supporting local ecosystems and potentially serving conservation goals. The dam is owned by Us Fish And Wildlife Service (federal). It impounds the Little Grassy Creek near Carbondale, Il.

The dam stands 88 feet tall and stretches 3,650 feet across, creates a reservoir covering 960 acres, has a maximum storage capacity of 30,900 acre-feet, and collects water from a drainage area of 15 square miles. Completed in 1942, 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/27/2016. That was 9 years ago, which is on the longer end for a high-hazard structure.

At 88 feet, this dam is taller than 97% of all dams in the United States.

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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