Monroe 4

Cottonwood River-TR· Lyon, Minnesota· Built 1989· 15 ft tall
Low Hazard Flood Risk Reduction Local Government

Key Takeaway

Monroe 4 is classified as low hazard in Minnesota. It was completed in 1989 and is 37 years old. Its primary use is flood risk reduction.

Physical Details

Dam Height 15 ft (taller than 50.4% in MN)
Dam Length380 ft
Max Storage121 acre-ft
Drainage Area8 sq mi
Year Completed1989 (37 years old)
NID IDMN01748

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

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

Emergency Action Plan: No
Last Inspection: April 5, 2019
State Regulated: Yes
Regulatory Agency: MNDNR EWR

Ownership

County of Lyon

Local Government

Nearby Dams

Twp Road 30 East

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Amiret 32

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Monroe 3

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Low Hazard 27 ft

Monroe 8

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Griffith-Glynn Farm Pond

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Twp Road 18

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Kass-Morgan Group Farm Pond

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Significant Hazard 26 ft

Frequently Asked Questions

What is the hazard classification of Monroe 4?

Monroe 4 is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Monroe 4?

Monroe 4 is owned by County of Lyon (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Monroe 4 built?

Monroe 4 was completed in 1989, making it 37 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 Monroe 4?

Monroe 4 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 Monroe 4?

Monroe 4 has a dam height of 15 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 Monroe 4 last inspected?

Monroe 4 was last inspected on April 5, 2019. 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.