Lake Decatur Dam
Key Takeaway
Lake Decatur Dam is classified as high hazard in Illinois. It was completed in 1922 and is 104 years old. Its primary use is recreation. 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 | 33 ft (taller than 71.6% in IL) |
| Dam Length | 1,728 ft |
| Dam Type | Earth |
| Max Storage | 57.5K acre-ft |
| Normal Storage | 18.4K acre-ft |
| Surface Area | 3,335 acres |
| Drainage Area | 906 sq mi |
| Max Discharge | 64,000 cfs |
| Year Completed | 1922 (104 years old) |
| NID ID | IL00146 |
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 DECATUR
Local Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Lake Decatur Dam?
Lake Decatur 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 Lake Decatur Dam?
Lake Decatur Dam is owned by CITY OF DECATUR (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lake Decatur Dam built?
Lake Decatur Dam was completed in 1922, making it 104 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 Lake Decatur Dam?
Lake Decatur Dam serves the following purposes: Recreation, Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lake Decatur Dam?
Lake Decatur Dam has a dam height of 33 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 Lake Decatur Dam last inspected?
Lake Decatur Dam was last inspected on August 19, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.