Simpson Lake Dam

TRIB BAY CREEK· Johnson, Illinois· Built 1963· Earth· 23 ft tall
Significant Hazard Recreation Private

Key Takeaway

Simpson Lake Dam is classified as significant hazard in Illinois. It was completed in 1963 and is 63 years old. Its primary use is recreation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 23 ft (taller than 37.7% in IL)
Dam Length690 ft
Dam TypeEarth
Max Storage222 acre-ft
Normal Storage123 acre-ft
Year Completed1963 (63 years old)
NID IDIL00071

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
Last Inspection: June 1, 2015
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

LEVI SIMPSON

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Simpson Lake Dam?

Simpson 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 Simpson Lake Dam?

Simpson Lake Dam is owned by LEVI SIMPSON (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Simpson Lake Dam built?

Simpson Lake Dam was completed in 1963, making it 63 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 Simpson Lake Dam?

Simpson 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 Simpson Lake Dam?

Simpson Lake Dam has a dam height of 23 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 Simpson Lake Dam last inspected?

Simpson Lake Dam was last inspected on June 1, 2015. 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.