French Lake Dam Reservoir Report
Last Updated: January 12, 2026
French Lake Dam, located in Macoupin, Illinois, is a privately owned structure built in 1970 by the USDA NRCS for recreational purposes.
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Summary
This earth dam stands at a height of 31 feet and stretches 825 feet in length, holding a maximum storage capacity of 86 acre-feet. The dam is regulated and inspected by the Illinois Department of Natural Resources, ensuring its safety and compliance with state standards.
With a low hazard potential and a moderate risk assessment score of 3, French Lake Dam poses minimal danger to surrounding areas but requires regular inspections every five years. The dam features an uncontrolled spillway and outlet gates, allowing for controlled water release when necessary. Despite its recreational purpose, the dam's primary focus is on providing a safe environment for visitors to enjoy activities such as fishing and boating in the French Lake area.
As part of the St. Louis District, French Lake Dam plays a crucial role in water resource management in the region. While its condition assessment is currently unavailable, the dam's design and construction by the Natural Resources Conservation Service ensure its structural integrity. As water resource and climate enthusiasts, understanding the importance of dams like French Lake in maintaining water supply, flood control, and recreational opportunities is vital for sustainable management of our natural resources.
Year Completed |
1970 |
Dam Length |
825 |
Dam Height |
31 |
River Or Stream |
HONEY CREE-OFFSTREAM |
Primary Dam Type |
Earth |
Nid Storage |
86 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
East Fork Shoal Creek Near Coffeen
|
6cfs |
Cahokia Creek At Edwardsville
|
5cfs |
Indian Creek At Wanda
|
0cfs |
Shoal Creek Nr Pierron
|
125cfs |
Macoupin Creek Near Kane
|
14cfs |
Silver Creek Near Troy
|
28cfs |
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.
French Lake Dam