Moccasin Lake Dam

Tr-Thompson Creek-Offstream· Okanogan, Washington· Built 1969· Earth·
High Hazard Irrigation Recreation Private

Key Takeaway

Moccasin Lake Dam is classified as high hazard in Washington. It was completed in 1969 and is 57 years old. Its primary use is irrigation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Length530 ft
Dam TypeEarth
Max Storage261 acre-ft
Normal Storage0 acre-ft
Surface Area27 acres
Drainage Area1 sq mi
Max Discharge35 cfs
Year Completed1969 (57 years old)
NID IDWA00053

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: No
Last Inspection: November 8, 2023
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Moccasin Lake Ranch #1 Inc.

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Moccasin Lake Dam?

Moccasin Lake Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Moccasin Lake Dam?

Moccasin Lake Dam is owned by Moccasin Lake Ranch #1 Inc. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Moccasin Lake Dam built?

Moccasin 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 Moccasin Lake Dam?

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

When was Moccasin Lake Dam last inspected?

Moccasin Lake Dam was last inspected on November 8, 2023. 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.