Lima

About Lima

The primary purpose of Lima is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Beaverhead County Red Rock River Water/sewer Dist. (local government). It impounds the Red Rock River near Lima.

The dam stands 56 feet tall and stretches 455 feet across, creates a reservoir covering 5,900 acres, has a maximum storage capacity of 133,000 acre-feet, and collects water from a drainage area of 570 square miles. Completed in 1934, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 10/01/2024.

At 56 feet, this dam is taller than 94% 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 Montana dam safety program can provide more specific information about emergency planning for this structure.

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