Johnson Dam
Key Takeaway
Johnson Dam is classified as low hazard in South Dakota. It was completed in 1972 and is 54 years old. Its primary use is irrigation.
Physical Details
| Dam Height | 20 ft (taller than 33.7% in SD) |
| Dam Length | 400 ft |
| Dam Type | Earth |
| Max Storage | 340 acre-ft |
| Normal Storage | 170 acre-ft |
| Surface Area | 17 acres |
| Max Discharge | 1,600 cfs |
| Year Completed | 1972 (54 years old) |
| NID ID | SD02393 |
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
WALLACE JOHNSON
Private
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Low Hazard 19 ftFrequently Asked Questions
What is the hazard classification of Johnson Dam?
Johnson 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 Johnson Dam?
Johnson Dam is owned by WALLACE JOHNSON (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Johnson Dam built?
Johnson Dam was completed in 1972, making it 54 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 Johnson Dam?
Johnson Dam serves the following purposes: Irrigation, 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.
How tall is Johnson Dam?
Johnson Dam has a dam height of 20 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.