Upper Mill Creek Stormwater Detention Da Reservoir Report
Last Updated: December 15, 2025
The Upper Mill Creek Stormwater Detention Dam, located in Kent, Washington, was completed in 1990 with the primary purpose of flood risk reduction along Mill Creek.
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Summary
This earth dam stands at a hydraulic height of 21 feet, with a length of 600 feet and a storage capacity of 167 acre-feet. With a drainage area of 1.24 square miles, the dam plays a crucial role in managing stormwater runoff and reducing the risk of flooding in the surrounding areas.
Managed by the local government in King County, this dam is regulated by the Washington Department of Ecology and undergoes regular inspections to ensure its structural integrity. Despite its high hazard potential, the dam has been assessed as satisfactory and meets the necessary guidelines for emergency action planning. With a capacity to handle a maximum discharge of 820 cubic feet per second, the Upper Mill Creek Stormwater Detention Dam is a vital infrastructure for water resource management in the region.
As a key component in the flood risk reduction strategy for the area, the Upper Mill Creek Stormwater Detention Dam serves as a critical infrastructure for safeguarding communities along Mill Creek. With its efficient design and satisfactory condition assessment, this dam continues to play a pivotal role in mitigating flood risks and protecting the environment. For water resource and climate enthusiasts, this dam exemplifies the importance of sustainable water management practices and the role of infrastructure in building resilience against climate change impacts.
Year Completed |
1990 |
Dam Length |
600 |
River Or Stream |
Mill Creek |
Primary Dam Type |
Earth |
Surface Area |
11 |
Hydraulic Height |
21 |
Drainage Area |
1.24 |
Nid Storage |
167 |
Structural Height |
21 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
21 |
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 |
|---|---|---|
Point Robinson Campground
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Dash Point State Park
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Dash Point Campground
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Upper Mill Creek Stormwater Detention Da
Lake Tapps Near Sumner
148th Avenue Southeast Kent