Longview Sewage Lagoon No 4 Reservoir Report
Last Updated: December 14, 2025
Longview Sewage Lagoon No 4, located in Longview, Washington, is a crucial infrastructure owned by the local government and regulated by the Washington Department of Ecology.
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Summary
This sewage lagoon plays a significant role in treating wastewater from the area, ensuring that the surrounding water bodies, including Tr-Coal Creek Slough-Offstream, are protected from pollution. Completed in 1987, this earth dam structure stands at a hydraulic height of 12 feet and a structural height of 4 feet, with a storage capacity of 60 acre-feet.
With a low hazard potential and a condition assessment that is currently not rated, Longview Sewage Lagoon No 4 serves its primary purpose effectively. Its design, comprising stone core and soil foundation, has been instrumental in managing wastewater and maintaining water quality in the region. The lagoon has a maximum discharge capacity of 8 cubic feet per second, providing adequate protection against flooding and overflow. Despite not having a designated spillway type or inspection frequency, this sewage lagoon remains a critical component of the local water resource management system.
As an essential part of the water infrastructure in Cowlitz County, Longview Sewage Lagoon No 4 offers insights into the state's commitment to environmental protection and sustainable water resource management practices. With its compliance with state regulations, state permitting, and enforcement measures, this sewage lagoon exemplifies the responsible stewardship of water resources in the region. As climate change continues to impact water availability and quality, facilities like Longview Sewage Lagoon No 4 play a vital role in safeguarding public health and the environment.
Year Completed |
1987 |
Dam Length |
2000 |
River Or Stream |
Tr-Coal Creek Slough-Offstream |
Primary Dam Type |
Earth |
Surface Area |
30 |
Hydraulic Height |
12 |
Drainage Area |
0.06 |
Nid Storage |
60 |
Structural Height |
4 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
12 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Hudson - Parcher County Park
|
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County Line Park
|
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Clatskanie City Park
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Longview Sewage Lagoon No 4