Old Gillespie Lake Dam
Key Takeaway
Old Gillespie Lake Dam is classified as low hazard in Illinois. It was completed in 1923 and is 103 years old. Its primary use is water supply.
Physical Details
| Dam Height | 35 ft (taller than 76.2% in IL) |
| Dam Length | 335 ft |
| Dam Type | Earth |
| Max Storage | 1.1K acre-ft |
| Normal Storage | 592 acre-ft |
| Surface Area | 71 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 3,598 cfs |
| Year Completed | 1923 (103 years old) |
| NID ID | IL00777 |
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
CITY OF GILLESPIE
Local Government
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Low Hazard 30 ftFrequently Asked Questions
What is the hazard classification of Old Gillespie Lake Dam?
Old Gillespie Lake 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 Old Gillespie Lake Dam?
Old Gillespie Lake Dam is owned by CITY OF GILLESPIE (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Old Gillespie Lake Dam built?
Old Gillespie Lake Dam was completed in 1923, making it 103 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 Old Gillespie Lake Dam?
Old Gillespie Lake 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 Old Gillespie Lake Dam?
Old Gillespie Lake Dam has a dam height of 35 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 Old Gillespie Lake Dam last inspected?
Old Gillespie Lake Dam was last inspected on October 3, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.