Monticello Milldam

MAQUOKETA RIVER· Jones, Iowa· Built 1914· Gravity· 12 ft tall
Low Hazard Recreation Local Government

Key Takeaway

Monticello Milldam is classified as low hazard in Iowa. It was completed in 1914 and is 112 years old. Its primary use is recreation.

Physical Details

Dam Height 12 ft (taller than 3.1% in IA)
Dam Length1,199 ft
Dam TypeGravity
Max Storage4.2K acre-ft
Normal Storage4.2K acre-ft
Surface Area700 acres
Drainage Area657 sq mi
Max Discharge0 cfs
Year Completed1914 (112 years old)
NID IDIA01313

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: September 28, 1989
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Jones County Conservation Board

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Monticello Milldam?

Monticello 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 Monticello Milldam?

Monticello Milldam is owned by Jones County Conservation Board (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Monticello Milldam built?

Monticello Milldam was completed in 1914, making it 112 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 Monticello Milldam?

Monticello 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 Monticello Milldam?

Monticello Milldam has a dam height of 12 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 Monticello Milldam last inspected?

Monticello Milldam was last inspected on September 28, 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.