Johnson Dam
Key Takeaway
Johnson Dam is classified as low hazard in Iowa. It was completed in 1974 and is 52 years old. Its primary use is water supply.
Physical Details
| Dam Height | 32 ft (taller than 58.4% in IA) |
| Dam Length | 370 ft |
| Dam Type | Earth |
| Max Storage | 59 acre-ft |
| Normal Storage | 41 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 0 cfs |
| Year Completed | 1974 (52 years old) |
| NID ID | IA01892 |
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
DA Johnson
Private
Nearby Dams
Adamson Dam
Decatur, IA
Low Hazard 23 ftKieser Dam
Decatur, IA
Low Hazard 23 ftHinebaugh Dam
Decatur, IA
Low Hazard 24 ftOlson Dam
Decatur, IA
Low Hazard 25 ftMcintyre Dam
Decatur, IA
Low Hazard 30 ftDoss Dam
Decatur, IA
Low Hazard 26 ftSponsler Dam
Clarke, IA
Low Hazard 22 ftSaxton Dam #2
Decatur, IA
Low Hazard 35 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 DA 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 1974, making it 52 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: Water Supply. 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 32 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.