Decorah Lower Milldam

UPPER IOWA RIVER· Winneshiek, Iowa· Built 1973· Gravity· 27 ft tall
Low Hazard Recreation State Government

Key Takeaway

Decorah Lower Milldam is classified as low hazard in Iowa. It was completed in 1973 and is 53 years old. Its primary use is recreation.

Physical Details

Dam Height 27 ft (taller than 30.7% in IA)
Dam Length500 ft
Dam TypeGravity
Max Storage1.3K acre-ft
Normal Storage1.1K acre-ft
Surface Area80 acres
Drainage Area645 sq mi
Max Discharge0 cfs
Year Completed1973 (53 years old)
NID IDIA01288

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: October 1, 2003
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Iowa Department of Natural Resources

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Decorah Lower Milldam?

Decorah Lower Milldam 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 Decorah Lower Milldam?

Decorah Lower Milldam is owned by Iowa Department of Natural Resources (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Decorah Lower Milldam built?

Decorah Lower Milldam was completed in 1973, making it 53 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 Decorah Lower Milldam?

Decorah Lower Milldam 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 Decorah Lower Milldam?

Decorah Lower Milldam has a dam height of 27 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 Decorah Lower Milldam last inspected?

Decorah Lower Milldam was last inspected on October 1, 2003. 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.