South Side Detention Basin Berm 3 Dam is an earth dam located in Coles County, Illinois, built in 2011. It carries a Low hazard potential classification.
Dam profile
NID height · 13 ft13 ft tall and 2,827 ft long. 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 South Side Detention Basin Berm 3 Dam
The primary purpose of South Side Detention Basin Berm 3 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 Mattoon (local government). It impounds the Trib Kickapoo Creek near Mattoon.
The dam stands 13 feet tall and stretches 2,827 feet across, has a maximum storage capacity of 97 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2011, the structure is relatively new.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 12/09/2025.
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Location
| State | Illinois |
| County | Coles |
| Nearest City | Mattoon |
| River/Stream | Trib Kickapoo Creek |
| Coordinates | 39.46181, -88.37111 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 2,827 ft |
| Year Completed | 2011 (15 years old) |
Storage & Hydraulics
| NID Storage | 97 acre-ft |
| Max Storage | 97 acre-ft |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | City of Mattoon |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 12/09/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL50638 |
| Federal ID | IL50638 |
| More Info | State Dam Safety Program |