Rosalia Sewage Lagoon is an earth dam located in Whitman County, Washington, built in 1989. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 10 ft10 ft tall and 2,000 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Rosalia Sewage Lagoon
Rosalia Sewage Lagoon is a dam in Whitman, Washington. The dam is owned by Rosalia Stp (local government).
The dam stands 10 feet tall and stretches 2,000 feet across, creates a reservoir covering 4 acres, has a maximum storage capacity of 37 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1989, the structure is 37 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 09/26/2023.
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Location
| State | Washington |
| County | Whitman |
| Coordinates | 47.24150, -117.37304 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Length | 2,000 ft |
| Year Completed | 1989 (37 years old) |
Storage & Hydraulics
| NID Storage | 37 acre-ft |
| Max Storage | 37 acre-ft |
| Normal Storage | 28 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Other |
| Owner | Rosalia Stp |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 09/26/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA02045 |
| Federal ID | WA02045 |
| More Info | State Dam Safety Program |