Connell Wastewater Lagoons Reservoir Report
Last Updated: December 14, 2025
The Connell Wastewater Lagoons in Washington state are a crucial water resource managed by the City of Connell.
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Summary
Designed by Anderson Perry & Assoc., these lagoons serve as offstream storage for the Providence Coulee, providing essential wastewater treatment for the community. Completed in 2000, the lagoons have a structural height of 20.5 feet and a hydraulic height of 27 feet, with a storage capacity of 90 acre-feet.
Despite being a local government-owned facility, the Connell Wastewater Lagoons are regulated, permitted, inspected, and enforced by the Washington Department of Ecology. The lagoons have a significant hazard potential but are currently in satisfactory condition. The last inspection in 2014 found the facility to be operating efficiently, with a scheduled inspection frequency of 5 years. With a surface area of 30.3 acres and a normal storage capacity of 60 acre-feet, the lagoons play a vital role in water resource management for the region.
Located in Franklin County, Washington, the Connell Wastewater Lagoons are part of the larger water infrastructure managed by the Walla Walla District of the US Army Corps of Engineers. With no associated structures or federal funding, the lagoons primarily serve the City of Connell and surrounding areas. The lagoons are a key component of the local water management system, ensuring proper treatment and storage of wastewater to protect the environment and public health.
Year Completed |
2000 |
Dam Length |
3275 |
River Or Stream |
Providence Coulee - Offstream |
Primary Dam Type |
Earth |
Surface Area |
30.3 |
Hydraulic Height |
27 |
Nid Storage |
90 |
Structural Height |
20.5 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
27 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Palouse River At Hooper
|
1030cfs |
Tucannon River Near Starbuck
|
174cfs |
Crab Creek Near Moses Lake
|
28cfs |
Yakima River At Kiona
|
23800cfs |
Crab Creek At Irby
|
2cfs |
Walla Walla River Near Touchet
|
1040cfs |
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.
Connell Wastewater Lagoons