Thunder Bay Lake Dam

TR-Four Mike Creek· Polk, Iowa· Built 2010· Earth· 19 ft tall
Significant Hazard Flood Risk Reduction Private

Key Takeaway

Thunder Bay Lake Dam is classified as significant hazard in Iowa. It was completed in 2010 and is 16 years old. Its primary use is flood risk reduction. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 19 ft (taller than 6.5% in IA)
Dam TypeEarth
Max Storage119 acre-ft
Normal Storage60 acre-ft
Surface Area6 acres
Drainage Area1 sq mi
Max Discharge1,835 cfs
Year Completed2010 (16 years old)
NID IDIA04174

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

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

Emergency Action Plan: No
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Prairie Crossing Investments Inc

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Thunder Bay Lake Dam?

Thunder Bay Lake Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Thunder Bay Lake Dam?

Thunder Bay Lake Dam is owned by Prairie Crossing Investments Inc (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Thunder Bay Lake Dam built?

Thunder Bay Lake Dam was completed in 2010, making it 16 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 Thunder Bay Lake Dam?

Thunder Bay Lake Dam 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 Thunder Bay Lake Dam?

Thunder Bay Lake Dam has a dam height of 19 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.

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.