Thorton Quarry Gap Dam

THORNTON QUARRY· Cook, Illinois· Built 2013· Concrete· 116 ft tall
High Hazard Flood Risk Reduction Private

Key Takeaway

Thorton Quarry Gap Dam is classified as high hazard in Illinois. It was completed in 2013 and is 13 years old. Its primary use is flood risk reduction. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 116 ft (taller than 99.7% in IL)
Dam Length220 ft
Dam TypeConcrete
Max Storage9.9K acre-ft
Normal Storage0 acre-ft
Drainage Area0 sq mi
Year Completed2013 (13 years old)
NID IDIL55136

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: Yes
Last Inspection: May 31, 2023
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

METROPOLITAN WATER RECLAMATION DISTRICT

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Thorton Quarry Gap Dam?

Thorton Quarry Gap Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Thorton Quarry Gap Dam?

Thorton Quarry Gap Dam is owned by METROPOLITAN WATER RECLAMATION DISTRICT (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Thorton Quarry Gap Dam built?

Thorton Quarry Gap Dam was completed in 2013, making it 13 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 Thorton Quarry Gap Dam?

Thorton Quarry Gap Dam serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Thorton Quarry Gap Dam?

Thorton Quarry Gap Dam has a dam height of 116 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 Thorton Quarry Gap Dam last inspected?

Thorton Quarry Gap Dam was last inspected on May 31, 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.