Sinlahekin Dam No 1
Key Takeaway
Sinlahekin Dam No 1 is classified as high hazard in Washington. It was completed in 1949 and is 77 years old. Its primary use is recreation. 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 Length | 180 ft |
| Dam Type | Earth |
| Max Storage | 333 acre-ft |
| Normal Storage | 175 acre-ft |
| Surface Area | 83 acres |
| Drainage Area | 64 sq mi |
| Max Discharge | 0 cfs |
| Year Completed | 1949 (77 years old) |
| NID ID | WA00007 |
Safety Information
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?
Ownership
WA DFW
State Government
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Low HazardFrequently Asked Questions
What is the hazard classification of Sinlahekin Dam No 1?
Sinlahekin Dam No 1 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 Sinlahekin Dam No 1?
Sinlahekin Dam No 1 is owned by WA DFW (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Sinlahekin Dam No 1 built?
Sinlahekin Dam No 1 was completed in 1949, making it 77 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 Sinlahekin Dam No 1?
Sinlahekin Dam No 1 serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
When was Sinlahekin Dam No 1 last inspected?
Sinlahekin Dam No 1 was last inspected on April 11, 2024. Inspection dates indicate when a formal review occurred, not the results of that inspection.