Otter Lake Dam

WEST FORK OTTER CREEK· Macoupin, Illinois· Built 1969· Earth· 71 ft tall
Significant Hazard Recreation Water Supply Public Utility

Key Takeaway

Otter Lake Dam is classified as significant hazard in Illinois. It was completed in 1969 and is 57 years old. Its primary use is recreation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 71 ft (taller than 97.4% in IL)
Dam Length1,010 ft
Dam TypeEarth
Max Storage24.7K acre-ft
Normal Storage15.6K acre-ft
Surface Area760 acres
Drainage Area20 sq mi
Max Discharge21,153 cfs
Year Completed1969 (57 years old)
NID IDIL00133

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: Yes
Last Inspection: April 30, 2020
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

OTTER LAKE WATER COMMISSION

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Otter Lake Dam?

Otter 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 Otter Lake Dam?

Otter Lake Dam is owned by OTTER LAKE WATER COMMISSION (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Otter Lake Dam built?

Otter Lake Dam was completed in 1969, making it 57 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 Otter Lake Dam?

Otter Lake Dam serves the following purposes: Recreation, Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Otter Lake Dam?

Otter Lake Dam has a dam height of 71 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 Otter Lake Dam last inspected?

Otter Lake Dam was last inspected on April 30, 2020. 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.