Mcarthur

About Mcarthur

Mcarthur is a dam in Boundary, Idaho. The dam is state-owned. It impounds the Deep Creek Kootenai River near Naples.

The dam stands 19 feet tall and stretches 600 feet across, creates a reservoir covering 266 acres, has a storage capacity of 1,085 acre-feet, and collects water from a drainage area of 27 square miles. Completed in 1967, 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 08/04/2020.

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 Idaho 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.