Seattle Port Lagoon No 3
Key Takeaway
Seattle Port Lagoon No 3 is classified as high hazard in Washington. It was completed in 2001 and is 25 years old. Its primary use is flood risk reduction. 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 | 1,500 ft |
| Dam Type | Earth |
| Max Storage | 256 acre-ft |
| Normal Storage | 235 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 140 cfs |
| Year Completed | 2001 (25 years old) |
| NID ID | WA00671 |
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
Port of Seattle
Local Government
Nearby Dams
Des Moines Ck Reg Det Pond West Berm
King, WA
High HazardDes Moines Ck Reg Det Facility East Berm
King, WA
High HazardDes Moines Creek Stormwater Detention Da
King, WA
High HazardSeatac Airport Se Pond
King, WA
Significant Hazard204th Street Stormwater Detention Basin
King, WA
Significant HazardSeatac Airport Pond G
King, WA
High HazardSeatac Airport Pond M
King, WA
High HazardMiller Creek Regional Detention Facility
King, WA
Significant HazardFrequently Asked Questions
What is the hazard classification of Seattle Port Lagoon No 3?
Seattle Port Lagoon No 3 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 Seattle Port Lagoon No 3?
Seattle Port Lagoon No 3 is owned by Port of Seattle (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Seattle Port Lagoon No 3 built?
Seattle Port Lagoon No 3 was completed in 2001, making it 25 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 Seattle Port Lagoon No 3?
Seattle Port Lagoon No 3 serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
When was Seattle Port Lagoon No 3 last inspected?
Seattle Port Lagoon No 3 was last inspected on July 10, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.