Sibley Green Site 4

About Sibley Green Site 4

The primary purpose of Sibley Green Site 4 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 Berrenda Arroyo near Unincorporated Residents.

The dam stands 80 feet tall and stretches 2,800 feet across, has a maximum storage capacity of 12,420 acre-feet, and collects water from a drainage area of 86 square miles. Completed in 1974, the structure is well into its service life at over 50 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. An emergency action plan is in place for this dam. The most recent inspection on record was 06/02/2015. That was 10 years ago — unusually long for a high-hazard dam, which typically requires more frequent inspections.

At 80 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 New Mexico dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.