Flat Rock Dam

Huron River· Wayne, Michigan· Built 1924· Gravity· 17 ft tall
High Hazard Recreation Local Government

Key Takeaway

Flat Rock Dam is classified as high hazard in Michigan. It was completed in 1924 and is 102 years old. Its primary use is recreation. 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 17 ft (taller than 61.1% in MI)
Dam Length530 ft
Dam TypeGravity
Max Storage2.4K acre-ft
Normal Storage1.6K acre-ft
Surface Area188 acres
Drainage Area876 sq mi
Max Discharge14,560 cfs
Year Completed1924 (102 years old)
NID IDMI00556

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: July 23, 2020
State Regulated: Yes
Regulatory Agency: MICHIGAN DEGLE

Ownership

Huron-Clinton Metro Authority

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Flat Rock Dam?

Flat Rock 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 Flat Rock Dam?

Flat Rock Dam is owned by Huron-Clinton Metro Authority (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Flat Rock Dam built?

Flat Rock Dam was completed in 1924, making it 102 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 Flat Rock Dam?

Flat Rock Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Flat Rock Dam?

Flat Rock Dam has a dam height of 17 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 Flat Rock Dam last inspected?

Flat Rock Dam was last inspected on July 23, 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.