Walla Walla Effluent Storage Lagoon Reservoir Report
Last Updated: December 15, 2025
The Walla Walla Effluent Storage Lagoon in Washington state serves as a vital water resource management facility designed by JUB Engineers in 2008.
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Summary
As a key component of the local government's infrastructure, this earth dam structure is regulated, permitted, inspected, and enforced by the Washington Department of Ecology. With a height of 19.45 feet and a storage capacity of 87 acre-feet, the lagoon plays a crucial role in storing and managing effluent in Walla Walla.
The Walla Walla Effluent Storage Lagoon is strategically located in Walla Walla, Washington, within Congressional District 05. With a surface area of 5.15 acres and a normal storage capacity of 78.2 acre-feet, the lagoon helps address water management needs in the region. Despite being classified as having a significant hazard potential, the dam is in fair condition as of the last inspection in April 2019. The lagoon's emergency action plan was prepared in 2008, ensuring that appropriate measures are in place to address any potential risks or emergencies.
Overall, the Walla Walla Effluent Storage Lagoon stands as a critical water resource infrastructure in Walla Walla, Washington, designed to effectively store and manage effluent. With its regulated and inspected status, the lagoon plays a key role in water resource management in the region, contributing to the overall environmental sustainability and water security of the area.
Year Completed |
2008 |
Dam Length |
1800 |
Primary Dam Type |
Earth |
Surface Area |
5.15 |
Hydraulic Height |
19.45 |
Nid Storage |
87 |
Structural Height |
19.45 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
19 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Mill Creek At Walla Walla
|
165cfs |
Mill Creek At Five Mile Rd Br Nr Walla Walla
|
634cfs |
Mill Creek Near Walla Walla
|
53cfs |
Walla Walla River Near Touchet
|
832cfs |
Umatilla River Above Meacham Creek
|
157cfs |
Meacham Creek At Gibbon
|
233cfs |
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.
Walla Walla Effluent Storage Lagoon