Olson Lake Dam

WILLOW CREEK· Winnebago, Illinois· Built 1991· Earth· 24 ft tall
Low Hazard Recreation State Government

Key Takeaway

Olson Lake Dam is classified as low hazard in Illinois. It was completed in 1991 and is 35 years old. Its primary use is recreation.

Physical Details

Dam Height 24 ft (taller than 40.5% in IL)
Dam Length1,130 ft
Dam TypeEarth
Max Storage630 acre-ft
Normal Storage218 acre-ft
Surface Area12 acres
Drainage Area9 sq mi
Max Discharge4,588 cfs
Year Completed1991 (35 years old)
NID IDIL50236

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 6, 2021
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

ILLINOIS DEPARTMENT OF NATURAL RESOURCES

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Olson Lake Dam?

Olson Lake Dam 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 Olson Lake Dam?

Olson Lake Dam is owned by ILLINOIS DEPARTMENT OF NATURAL RESOURCES (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Olson Lake Dam built?

Olson Lake Dam was completed in 1991, making it 35 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 Olson Lake Dam?

Olson Lake Dam 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 Olson Lake Dam?

Olson Lake Dam has a dam height of 24 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 Olson Lake Dam last inspected?

Olson Lake Dam was last inspected on October 6, 2021. 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.