Heritage Lake Dam is an earth dam located in Tazewell County, Illinois, built in 1968. It carries a Significant hazard potential classification.
Dam profile
NID height · 56 ft56 ft tall and 590 ft long, taller than 94% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Heritage Lake Dam
The primary purpose of Heritage Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Heritage Lake Association, Inc. (private). It impounds the Trib Mackinaw River near Mackinaw.
The dam stands 56 feet tall and stretches 590 feet across, creates a reservoir covering 78 acres, has a maximum storage capacity of 2,425 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1968, the structure is well into its service life at over 50 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 11/22/2024.
At 56 feet, this dam is taller than 94% of dams nationwide.
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Location
| State | Illinois |
| County | Tazewell |
| Nearest City | Mackinaw |
| River/Stream | Trib Mackinaw River |
| Coordinates | 40.54735, -89.34117 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 56 ft |
| Dam Height | 56 ft |
| Dam Length | 590 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 2,425 acre-ft |
| Max Storage | 2,425 acre-ft |
| Normal Storage | 1,703 acre-ft |
| Surface Area | 78 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 1,820 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Heritage Lake Association, Inc. |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 11/22/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00346 |
| Federal ID | IL00346 |
| More Info | State Dam Safety Program |