Exxonmobil Coal Usa/mine 2/freshwater Lake Dam is a rockfill dam located in Clinton County, Illinois, built in 1975. It carries a Low hazard potential classification.
Dam profile
NID height · 15 ft15 ft tall and 800 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic rockfill embankment section and the water level is illustrative.
About Exxonmobil Coal Usa/mine 2/freshwater Lake Dam
The primary purpose of Exxonmobil Coal Usa/mine 2/freshwater Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Exxonmobil Environmental Services Compan (private). It impounds the Trib Grassy Branch near Damiansville.
The dam stands 15 feet tall and stretches 800 feet across, creates a reservoir covering 545 acres, has a maximum storage capacity of 423 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1975, the structure is well into its service life at over 50 years old.
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. The most recent inspection on record was 07/24/2025.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Illinois |
| County | Clinton |
| Nearest City | Damiansville |
| River/Stream | Trib Grassy Branch |
| Coordinates | 38.53631, -89.60401 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 800 ft |
| Year Completed | 1975 (51 years old) |
Storage & Hydraulics
| NID Storage | 423 acre-ft |
| Max Storage | 423 acre-ft |
| Normal Storage | 187 acre-ft |
| Surface Area | 545 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 230 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Exxonmobil Environmental Services Compan |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 07/24/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL50527 |
| Federal ID | IL50527 |
| More Info | State Dam Safety Program |