Lewis Dam is an earth dam located in McDonough County, Illinois. It carries a Low hazard potential classification.
Dam profile
NID height · 28 ft28 ft tall and 490 ft long, taller than 62% 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 Lewis Dam
The primary purpose of Lewis Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Jerry Lewis (private). It impounds the Trib Farmers Fork near Macomb.
The dam stands 28 feet tall and stretches 490 feet across, creates a reservoir covering 10 acres, has a maximum storage capacity of 133 acre-feet, and collects water from a drainage area of 0 square miles.
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 05/09/2025.
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Location
| State | Illinois |
| County | McDonough |
| Nearest City | Macomb |
| River/Stream | Trib Farmers Fork |
| Coordinates | 40.54074, -90.62616 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 490 ft |
Storage & Hydraulics
| NID Storage | 133 acre-ft |
| Max Storage | 133 acre-ft |
| Normal Storage | 70 acre-ft |
| Surface Area | 10 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 355 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Jerry Lewis |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 05/09/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL50537 |
| Federal ID | IL50537 |
| More Info | State Dam Safety Program |