Heritage Lake Dam Reservoir Report
Last Updated: December 21, 2025
Heritage Lake Dam in Illinois is a privately owned structure with a primary purpose of recreation.
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Summary
Completed in 1968, the earth dam stands at 56 feet tall and spans 590 feet in length, holding a maximum storage capacity of 2425 acre-feet. Situated on the tributary of the Mackinaw River, the dam's spillway type is uncontrolled, with a width of 315 feet. The dam poses a significant hazard potential and is inspected every three years, with the last inspection conducted in September 2020.
This dam, managed by the Illinois Department of Natural Resources, plays a crucial role in providing recreational opportunities and regulating water flow in the region. Its moderate risk level (3) necessitates ongoing risk management measures to ensure the safety and integrity of the structure. Despite its unknown designer and foundation type, Heritage Lake Dam remains a key feature in the Tazewell County landscape, offering not only recreational benefits but also serving as a vital component of the local water resource infrastructure.
Water resource and climate enthusiasts are drawn to Heritage Lake Dam for its strategic location, impressive dimensions, and significant impact on the surrounding environment. With a rich history dating back to the late 1960s, this earth dam continues to be a focal point for water management and conservation efforts in Illinois. Its role in providing both recreational opportunities and flood control measures make Heritage Lake Dam a valuable asset worth monitoring and preserving for future generations.
Year Completed |
1968 |
Dam Length |
590 |
Dam Height |
56 |
River Or Stream |
TRIB MACKINAW RIVER |
Primary Dam Type |
Earth |
Surface Area |
78 |
Drainage Area |
1.9 |
Nid Storage |
2425 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
56 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Heritage Lake Dam