Chessman Main Dam
Key Takeaway
Chessman Main Dam is classified as high hazard in Montana. It was completed in 1908 and is 118 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 57 ft (taller than 97.3% in MT) |
| Dam Length | 440 ft |
| Dam Type | Earth |
| Max Storage | 2.4K acre-ft |
| Normal Storage | 1.6K acre-ft |
| Surface Area | 114 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 30 cfs |
| Year Completed | 1908 (118 years old) |
| Year Modified | 1988 |
| NID ID | MT01090 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
CITY OF HELENA
Local Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Chessman Main Dam?
Chessman Main Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Chessman Main Dam?
Chessman Main Dam is owned by CITY OF HELENA (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Chessman Main Dam built?
Chessman Main Dam was completed in 1908, making it 118 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 Chessman Main Dam?
Chessman Main Dam serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Chessman Main Dam?
Chessman Main Dam has a dam height of 57 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Chessman Main Dam last inspected?
Chessman Main Dam was last inspected on August 27, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.