Sibley Green Site 5

About Sibley Green Site 5

The primary purpose of Sibley Green Site 5 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 Caballo Soil & Water Conservation District (local government). It impounds the Jaralosa Arroyo near Unincorporated Residents.

The dam stands 39 feet tall and stretches 4,400 feet across, creates a reservoir covering 88 acres, has a maximum storage capacity of 895 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1977, the structure is 49 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 02/27/2018. That was 8 years ago, which is on the longer end for a high-hazard structure.

At 39 feet, this dam is taller than 86% 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 New Mexico dam safety program can provide more specific information about emergency planning for this structure.

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