Greendale Lake Dam
Greendale Lake Dam is an earth dam located in Clay County, Illinois, built in 1926. It carries a Significant hazard potential classification.
About Greendale Lake Dam
The primary purpose of Greendale Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is private-owned. It impounds the Conners Branch near Wayne City.
The dam stands 15 feet tall and stretches 540 feet across, and has a maximum storage capacity of 311 acre-feet. Completed in 1926, the structure is well-established, with more than 75 years of service.
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. The most recent inspection on record was 06/20/2025.
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Location
| State | Illinois |
| County | Clay |
| Nearest City | Wayne City |
| River/Stream | Conners Branch |
| Coordinates | 38.65198, -88.69351 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 540 ft |
| Year Completed | 1926 (100 years old) |
Storage & Hydraulics
| NID Storage | 311 acre-ft |
| Max Storage | 311 acre-ft |
| Normal Storage | 170 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 06/20/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00155 |
| Federal ID | IL00155 |
| More Info | State Dam Safety Program |