Davenport Sewage Lagoon No 3 Reservoir Report
Last Updated: December 15, 2025
Davenport Sewage Lagoon No 3, located in Davenport, Washington, is a key water resource managed by the local government for treating sewage in the region.
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Summary
Built in 1987, this Earth-type dam stands at a structural height of 11 feet and has a storage capacity of 48 acre-feet. With a surface area of 7.1 acres and a drainage area of 0.01 square miles, the lagoon plays a crucial role in maintaining water quality in the Tr-Cottonwood Creek-Offstream area.
Despite being categorized with a 'High' hazard potential, the dam is deemed to be in 'Fair' condition as of the last assessment in 2016. The Washington Department of Ecology oversees the state regulation, permitting, inspection, and enforcement of this facility, ensuring its compliance with safety standards. The dam's emergency action plan was last revised in October 2019, emphasizing the importance of preparedness and risk management in the event of any potential hazards.
With Congresswoman Cathy McMorris Rodgers representing the area in Congressional District 05, Davenport Sewage Lagoon No 3 serves as a vital infrastructure for wastewater management in Lincoln County. As climate change continues to impact water resources, the maintenance and upkeep of such facilities are crucial in ensuring the resilience of communities against environmental challenges. This lagoon stands as a testament to the collaborative efforts between local and state agencies in safeguarding water quality and public health in the region.
Year Completed |
1987 |
Dam Length |
2360 |
River Or Stream |
Tr-Cottonwood Creek-Offstream |
Primary Dam Type |
Earth |
Surface Area |
7.1 |
Hydraulic Height |
11 |
Drainage Area |
0.01 |
Nid Storage |
48 |
Structural Height |
11 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
11 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Chamokane Creek Below Falls Near Long Lake
|
32cfs |
Coal Creek At Mohler
|
1cfs |
Spokane River Below Nine Mile Dam At Spokane
|
17300cfs |
Little Spokane River Near Dartford
|
527cfs |
Hangman Creek At Spokane
|
98cfs |
Spokane River At Spokane
|
17500cfs |
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.
Davenport Sewage Lagoon No 3