Petrolia
Key Takeaway
Petrolia is classified as high hazard in Montana. It was completed in 1951 and is 75 years old. Its primary use is irrigation. 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 | 76 ft (taller than 98.4% in MT) |
| Dam Length | 3,635 ft |
| Dam Type | Earth |
| Max Storage | 14.2K acre-ft |
| Normal Storage | 9.2K acre-ft |
| Surface Area | 515 acres |
| Drainage Area | 612 sq mi |
| Max Discharge | 10,200 cfs |
| Year Completed | 1951 (75 years old) |
| NID ID | MT00008 |
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
PETROLIA IRRIGATION DISTRICT
Local Government
Nearby Dams
Hassett #2
Petroleum, MT
Low Hazard 15 ftHassett #1
Petroleum, MT
Low Hazard 30 ftHassett #3
Petroleum, MT
Low Hazard 30 ftSandman #1
Petroleum, MT
Low Hazard 20 ftSeminary #10
Petroleum, MT
Low Hazard 18 ftWiggins #2
Petroleum, MT
Low Hazard 12 ftBethel #1
Petroleum, MT
Low Hazard 20 ftBethel #11
Petroleum, MT
Low Hazard 22 ftFrequently Asked Questions
What is the hazard classification of Petrolia?
Petrolia 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 Petrolia?
Petrolia is owned by PETROLIA IRRIGATION DISTRICT (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Petrolia built?
Petrolia was completed in 1951, making it 75 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 Petrolia?
Petrolia serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Petrolia?
Petrolia has a dam height of 76 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 Petrolia last inspected?
Petrolia was last inspected on April 26, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.