Bass Lake

About Bass Lake

The primary purpose of Bass Lake 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 Bass Lake Reservoir Co. (private). It impounds the Bass Creek near Florence.

The dam stands 35 feet tall and stretches 450 feet across, creates a reservoir covering 93 acres, has a maximum storage capacity of 3,900 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1887, the structure is over a century 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. Notably, no emergency action plan is currently on file for this high-hazard dam.

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 Montana 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.