Rosalia Sewage Lagoon

Whitman, Washington· Built 1989· Earth·
High Hazard Other Local Government

Key Takeaway

Rosalia Sewage Lagoon is classified as high hazard in Washington. It was completed in 1989 and is 37 years old. Its primary use is other. 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 TypeEarth
Max Storage37 acre-ft
Normal Storage28 acre-ft
Surface Area5 acres
Drainage Area0 sq mi
Max Discharge0 cfs
Year Completed1989 (37 years old)
NID IDWA02045

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: December 2, 2022
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Rosalia STP

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Rosalia Sewage Lagoon?

Rosalia Sewage Lagoon 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 Rosalia Sewage Lagoon?

Rosalia Sewage Lagoon is owned by Rosalia STP (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Rosalia Sewage Lagoon built?

Rosalia Sewage Lagoon was completed in 1989, making it 37 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 Rosalia Sewage Lagoon?

Rosalia Sewage Lagoon serves the following purposes: Other. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Rosalia Sewage Lagoon last inspected?

Rosalia Sewage Lagoon was last inspected on December 2, 2022. 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.