Lake Glenn Shoals Dam
Lake Glenn Shoals Dam is an earth dam located in Montgomery County, Illinois, built in 1978. It carries a Significant hazard potential classification.
About Lake Glenn Shoals Dam
The primary purpose of Lake Glenn Shoals Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by City Of Hillsboro (local government). It impounds the Middle Fork Of Shoal Creek near Hillsboro.
The dam stands 56 feet tall and stretches 1,430 feet across, and has a maximum storage capacity of 38,900 acre-feet. Completed in 1978, the structure is 48 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 09/17/2024.
At 56 feet, this dam is taller than 94% of dams nationwide.
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Location
| State | Illinois |
| County | Montgomery |
| Nearest City | Hillsboro |
| River/Stream | Middle Fork Of Shoal Creek |
| Coordinates | 39.18645, -89.47861 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 56 ft |
| Dam Height | 56 ft |
| Dam Length | 1,430 ft |
| Year Completed | 1978 (48 years old) |
Storage & Hydraulics
| NID Storage | 38,900 acre-ft |
| Max Storage | 38,900 acre-ft |
| Normal Storage | 13,000 acre-ft |
| Max Discharge | 20,800 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | CITY OF HILLSBORO |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 09/17/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00971 |
| Federal ID | IL00971 |
| More Info | State Dam Safety Program |