Upper Big Blue River Structure No. 18

About Upper Big Blue River Structure No. 18

The primary purpose of Upper Big Blue River Structure No. 18 is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Upper Big Blue Conservancy District (local government). It impounds the Unnamed Tributary Big Blue River near New Castle.

The dam stands 45 feet tall and stretches 875 feet across, creates a reservoir covering 24 acres, has a maximum storage capacity of 2,420 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1994, the structure is 32 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 10/13/2020.

At 45 feet, this dam is taller than 91% 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 Indiana dam safety program can provide more specific information about emergency planning for this structure.

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