J Janssen #1
Key Takeaway
J Janssen #1 is classified as low hazard in Montana. It was completed in 1940 and is 86 years old. Its primary use is irrigation.
Physical Details
| Dam Height | 16 ft (taller than 31.7% in MT) |
| Dam Length | 480 ft |
| Dam Type | Earth |
| Max Storage | 151 acre-ft |
| Normal Storage | 151 acre-ft |
| Drainage Area | 15 sq mi |
| Max Discharge | 500 cfs |
| Year Completed | 1940 (86 years old) |
| NID ID | MT01723 |
Safety Information
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?
Ownership
JOHN JANSSEN
Private
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Low Hazard 27 ftFrequently Asked Questions
What is the hazard classification of J Janssen #1?
J Janssen #1 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 J Janssen #1?
J Janssen #1 is owned by JOHN JANSSEN (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was J Janssen #1 built?
J Janssen #1 was completed in 1940, making it 86 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 J Janssen #1?
J Janssen #1 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 J Janssen #1?
J Janssen #1 has a dam height of 16 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.