Cedar Way Stormwater Detention Dam

Lyons Creek· Snohomish, Washington· Built 1985· Earth·
High Hazard Flood Risk Reduction Local Government

Key Takeaway

Cedar Way Stormwater Detention Dam is classified as high hazard in Washington. It was completed in 1985 and is 41 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 Length175 ft
Dam TypeEarth
Max Storage33 acre-ft
Normal Storage0 acre-ft
Surface Area3 acres
Drainage Area2 sq mi
Max Discharge860 cfs
Year Completed1985 (41 years old)
NID IDWA01404

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: Yes
Last Inspection: March 22, 2024
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Mountlake Terrace City

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cedar Way Stormwater Detention Dam?

Cedar Way Stormwater Detention 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 Cedar Way Stormwater Detention Dam?

Cedar Way Stormwater Detention Dam is owned by Mountlake Terrace City (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cedar Way Stormwater Detention Dam built?

Cedar Way Stormwater Detention Dam was completed in 1985, making it 41 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 Cedar Way Stormwater Detention Dam?

Cedar Way Stormwater Detention Dam 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 Cedar Way Stormwater Detention Dam last inspected?

Cedar Way Stormwater Detention Dam was last inspected on March 22, 2024. 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.