Mcmicken

About Mcmicken

The primary purpose of Mcmicken 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 Flood Control District Of Maricopa County (local government). It impounds the Trilby Wash near Surprise.

The dam stands 35 feet tall and stretches 46,200 feet across, creates a reservoir covering 2,230 acres, has a maximum storage capacity of 23,800 acre-feet, and collects water from a drainage area of 247 square miles. Completed in 1956, 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 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 02/05/2024.

At 35 feet, this dam is taller than 82% 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 Arizona 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.