Flat Retention Dam / Mister Bill Dam

BEAVER CK./MILK RIVER· Phillips, Montana· Built 1973· Gravity·
Low Hazard Fire Protection Stock Or Small Fish Pond Federal Government

Key Takeaway

Flat Retention Dam / Mister Bill Dam is classified as low hazard in Montana. It was completed in 1973 and is 53 years old. Its primary use is fire protection.

Physical Details

Dam Length1,553 ft
Dam TypeGravity
Max Storage1.5K acre-ft
Surface Area181 acres
Drainage Area1 sq mi
Year Completed1973 (53 years old)
Year Modified1973
NID IDMT03163

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: No
Last Inspection: August 16, 2016
State Regulated: No

Ownership

DOI BLM

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Flat Retention Dam / Mister Bill Dam?

Flat Retention Dam / Mister Bill Dam is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Flat Retention Dam / Mister Bill Dam?

Flat Retention Dam / Mister Bill Dam is owned by DOI BLM (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Flat Retention Dam / Mister Bill Dam built?

Flat Retention Dam / Mister Bill Dam was completed in 1973, making it 53 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Flat Retention Dam / Mister Bill Dam?

Flat Retention Dam / Mister Bill Dam serves the following purposes: Fire Protection, Stock, Or Small Fish Pond. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Flat Retention Dam / Mister Bill Dam last inspected?

Flat Retention Dam / Mister Bill Dam was last inspected on August 16, 2016. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.