Manchester Milldam

MAQUOKETA RIVER· Delaware, Iowa· Built 1905· Gravity· 11 ft tall
Low Hazard Recreation Public Utility

Key Takeaway

Manchester Milldam is classified as low hazard in Iowa. It was completed in 1905 and is 121 years old. Its primary use is recreation.

Physical Details

Dam Height 11 ft (taller than 2.5% in IA)
Dam Length201 ft
Dam TypeGravity
Max Storage395 acre-ft
Normal Storage395 acre-ft
Surface Area70 acres
Drainage Area268 sq mi
Max Discharge0 cfs
Year Completed1905 (121 years old)
NID IDIA01303

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 25, 1989
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Alliant Power Co

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Manchester Milldam?

Manchester 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 Manchester Milldam?

Manchester Milldam is owned by Alliant Power Co (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Manchester Milldam built?

Manchester Milldam was completed in 1905, making it 121 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 Manchester Milldam?

Manchester 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 Manchester Milldam?

Manchester Milldam has a dam height of 11 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 Manchester Milldam last inspected?

Manchester Milldam was last inspected on October 25, 1989. 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.