Little Grassy Dam
Key Takeaway
Little Grassy Dam is classified as high hazard in Illinois. It was completed in 1942 and is 84 years old. Its primary use is fish and wildlife pond. 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 | 88 ft (taller than 98.9% in IL) |
| Dam Length | 3,650 ft |
| Dam Type | Earth |
| Max Storage | 30.9K acre-ft |
| Normal Storage | 24.0K acre-ft |
| Surface Area | 960 acres |
| Drainage Area | 16 sq mi |
| Max Discharge | 35,943 cfs |
| Year Completed | 1942 (84 years old) |
| NID ID | IL00084 |
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
US FISH AND WILDLIFE SERVICE
Federal Government
Nearby Dams
Spring Arbor Lake Dam
Jackson, IL
High Hazard 55 ftAquaculture Lake Dam
Jackson, IL
Low Hazard 40 ftDevil`S Kitchen Dam
Williamson, IL
High Hazard 83 ftLake Indian Hills Dam
Jackson, IL
Low Hazard 36 ftCrab Orchard Dam
Williamson, IL
High Hazard 57 ftDam A-41
Williamson, IL
Low Hazard 24 ftBleyar Lake Dam
Williamson, IL
Low Hazard 20 ftStone Creek Golf Club Lake Dam
Jackson, IL
High Hazard 43 ftFrequently Asked Questions
What is the hazard classification of Little Grassy Dam?
Little Grassy 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 Little Grassy Dam?
Little Grassy Dam is owned by US FISH AND WILDLIFE SERVICE (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Little Grassy Dam built?
Little Grassy Dam was completed in 1942, making it 84 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 Little Grassy Dam?
Little Grassy Dam serves the following purposes: Fish And Wildlife Pond, Recreation, Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Little Grassy Dam?
Little Grassy Dam has a dam height of 88 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 Little Grassy Dam last inspected?
Little Grassy Dam was last inspected on July 27, 2016. Inspection dates indicate when a formal review occurred, not the results of that inspection.