Coffeen Power Sta. Supplemental Cooling Lake Dam is an earth dam located in Montgomery County, Illinois, built in 2000. It carries a Significant hazard potential classification.
Dam profile
NID height · 21 ft21 ft tall and 8,485 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 Coffeen Power Sta. Supplemental Cooling Lake Dam
Coffeen Power Sta. Supplemental Cooling Lake Dam is a dam in Montgomery, Illinois. The dam is owned by Dynegy Midwest Generation, Inc. (public utility). It impounds the Trib Mcdavid Branch near Coffeen.
The dam stands 21 feet tall and stretches 8,485 feet across, creates a reservoir covering 80 acres, has a maximum storage capacity of 735 acre-feet, and collects water from a drainage area of 80 square miles. Completed in 2000, the structure is 26 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 10/02/2023.
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Location
| State | Illinois |
| County | Montgomery |
| Nearest City | Coffeen |
| River/Stream | Trib Mcdavid Branch |
| Coordinates | 39.06238, -89.38949 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 21 ft |
| Dam Height | 21 ft |
| Dam Length | 8,485 ft |
| Year Completed | 2000 (26 years old) |
Storage & Hydraulics
| NID Storage | 735 acre-ft |
| Max Storage | 735 acre-ft |
| Normal Storage | 495 acre-ft |
| Surface Area | 80 acres |
| Drainage Area | 80 sq mi |
| Max Discharge | 4,447 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Other |
| Owner | Dynegy Midwest Generation, Inc. |
| Owner Type | Public Utility |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 10/02/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL50457 |
| Federal ID | IL50457 |
| More Info | State Dam Safety Program |