Carthage Lake 1 Dam is an earth dam located in Hancock County, Illinois, built in 1924. It carries a Significant hazard potential classification.
Dam profile
NID height · 38 ft38 ft tall and 521 ft long, taller than 84% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Carthage Lake 1 Dam
The primary purpose of Carthage Lake 1 Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City of Carthage (local government). It impounds the Trib Long Creek near Carthage-offstream.
The dam stands 38 feet tall and stretches 521 feet across, and has a maximum storage capacity of 770 acre-feet. Completed in 1924, the structure is over a century 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. The most recent inspection on record was 06/20/2024.
At 38 feet, this dam is taller than 84% of dams nationwide.
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Location
| State | Illinois |
| County | Hancock |
| Nearest City | Carthage-offstream |
| River/Stream | Trib Long Creek |
| Coordinates | 40.42925, -91.15212 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 38 ft |
| Dam Height | 38 ft |
| Dam Length | 521 ft |
| Year Completed | 1924 (102 years old) |
Storage & Hydraulics
| NID Storage | 770 acre-ft |
| Max Storage | 770 acre-ft |
| Normal Storage | 508 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Carthage |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 06/20/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00251 |
| Federal ID | IL00251 |
| More Info | State Dam Safety Program |