Mill Creek Structure 1 Dam

MILL CREEK· Clark, Illinois· Built 1980· Earth· 81 ft tall
Significant Hazard Flood Risk Reduction Recreation Private

Key Takeaway

Mill Creek Structure 1 Dam is classified as significant hazard in Illinois. It was completed in 1980 and is 46 years old. Its primary use is flood risk reduction. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 81 ft (taller than 98.4% in IL)
Dam Length1,470 ft
Dam TypeEarth
Max Storage40.3K acre-ft
Normal Storage17.5K acre-ft
Surface Area811 acres
Drainage Area21 sq mi
Max Discharge39,280 cfs
Year Completed1980 (46 years old)
NID IDIL01233

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: June 14, 2023
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

CLARK COUNTY PARK DISTRICT

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mill Creek Structure 1 Dam?

Mill Creek Structure 1 Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Mill Creek Structure 1 Dam?

Mill Creek Structure 1 Dam is owned by CLARK COUNTY PARK DISTRICT (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Mill Creek Structure 1 Dam built?

Mill Creek Structure 1 Dam was completed in 1980, making it 46 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Mill Creek Structure 1 Dam?

Mill Creek Structure 1 Dam serves the following purposes: Flood Risk Reduction, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Mill Creek Structure 1 Dam?

Mill Creek Structure 1 Dam has a dam height of 81 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Mill Creek Structure 1 Dam last inspected?

Mill Creek Structure 1 Dam was last inspected on June 14, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.