Lake Nelson Dam is an earth dam located in Mercer County, Illinois, built in 1937. It carries a Low hazard potential classification.
Dam profile
NID height · 14 ft14 ft tall and 300 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 Lake Nelson Dam
Lake Nelson Dam is a dam in Mercer, Illinois. The dam is owned by Sam Nelson (private). It impounds the Trib Eliza Creek near Petersville.
The dam stands 14 feet tall and stretches 300 feet across, and has a maximum storage capacity of 65 acre-feet. Completed in 1937, the structure is well-established, with more than 75 years of service.
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 05/02/2025.
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Location
| State | Illinois |
| County | Mercer |
| Nearest City | Petersville |
| River/Stream | Trib Eliza Creek |
| Coordinates | 41.30015, -90.83843 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 300 ft |
| Year Completed | 1937 (89 years old) |
Storage & Hydraulics
| NID Storage | 65 acre-ft |
| Max Storage | 65 acre-ft |
| Normal Storage | 39 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | Sam Nelson |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 05/02/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00495 |
| Federal ID | IL00495 |
| More Info | State Dam Safety Program |