Mill Creek Structure 9 Dam Reservoir Report
Last Updated: December 22, 2025
Mill Creek Structure 9 Dam, also known as Mill Creek Impoundment 9, is a private dam located in Snyder, Illinois along the Joes Fork river.
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Summary
Constructed in 1986 by the USDA NRCS, this earth dam stands at a height of 46 feet and has a length of 760 feet. The primary purpose of the dam is flood risk reduction, with additional benefits for recreation.
Managed by the Illinois Department of Natural Resources, Mill Creek Structure 9 Dam is regulated, permitted, inspected, and enforced by state agencies to ensure its safety and compliance with regulations. With a low hazard potential and a moderate risk assessment rating, the dam serves as a crucial infrastructure for managing water resources in Clark County. The dam's uncontrolled spillway and outlet gates contribute to its flood risk reduction capabilities, with a maximum discharge capacity of 6206 cubic feet per second.
Water resource and climate enthusiasts will find Mill Creek Structure 9 Dam to be an interesting case study in dam construction and management. Its design, purpose, and regulatory oversight offer insights into how dams can help mitigate flood risks while providing recreational opportunities. With a history of construction by the USDA NRCS and ongoing state agency involvement, this dam serves as a valuable asset for water management in Illinois.
Year Completed |
1986 |
Dam Length |
760 |
Dam Height |
46 |
River Or Stream |
JOES FORK |
Primary Dam Type |
Earth |
Nid Storage |
4483 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
46 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Wabash River At Riverton Ind
|
2610cfs |
North Fork Embarras River Near Oblong
|
53cfs |
Wabash River At Terre Haute
|
2380cfs |
Busseron Creek Near Carlisle
|
138cfs |
Embarras River At Ste. Marie
|
65cfs |
Big Raccoon Creek At Coxville
|
100cfs |
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.
Mill Creek Structure 9 Dam