Patterson Lake Dam

Rader Creek· Okanogan, Washington· Built 1924· Earth·
High Hazard Irrigation Recreation Water Supply Public Utility

Key Takeaway

Patterson Lake Dam is classified as high hazard in Washington. It was completed in 1924 and is 102 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 Length260 ft
Dam TypeEarth
Max Storage4.1K acre-ft
Normal Storage2.5K acre-ft
Surface Area150 acres
Drainage Area6 sq mi
Max Discharge260 cfs
Year Completed1924 (102 years old)
NID IDWA00073

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: August 19, 2023
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Wolf Creek Reclamation District

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Patterson Lake Dam?

Patterson 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 Patterson Lake Dam?

Patterson Lake Dam is owned by Wolf Creek Reclamation District (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Patterson Lake Dam built?

Patterson Lake Dam was completed in 1924, making it 102 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 Patterson Lake Dam?

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

When was Patterson Lake Dam last inspected?

Patterson Lake Dam was last inspected on August 19, 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.