Coffeen Gmf Gypsum Stack Dam

MCDAVID BRANCH EAST FORK SHOAL· Montgomery, Illinois· Earth· 108 ft tall
High Hazard Debris Control Public Utility

Key Takeaway

Coffeen Gmf Gypsum Stack Dam is classified as high hazard in Illinois. Its primary use is debris control. 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 108 ft (taller than 99.4% in IL)
Dam Length5,100 ft
Dam TypeEarth
Max Storage2.4K acre-ft
Normal Storage0 acre-ft
Surface Area39 acres
Drainage Area39 sq mi
Max Discharge1,100 cfs
NID IDIL50579

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: November 16, 2020
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

DYNEGY MIDWEST GENERATION, INC.

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Coffeen Gmf Gypsum Stack Dam?

Coffeen Gmf Gypsum Stack 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 Coffeen Gmf Gypsum Stack Dam?

Coffeen Gmf Gypsum Stack Dam is owned by DYNEGY MIDWEST GENERATION, INC. (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

What is the primary purpose of Coffeen Gmf Gypsum Stack Dam?

Coffeen Gmf Gypsum Stack Dam serves the following purposes: Debris Control. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Coffeen Gmf Gypsum Stack Dam?

Coffeen Gmf Gypsum Stack Dam has a dam height of 108 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 Coffeen Gmf Gypsum Stack Dam last inspected?

Coffeen Gmf Gypsum Stack Dam was last inspected on November 16, 2020. 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.