Tukwila South Project South Pond Reservoir Report
Last Updated: December 15, 2025
The Tukwila South Project South Pond is a flood risk reduction infrastructure located in King County, Washington.
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Summary
Designed by Goldsmith Associates and completed in 2011, this offstream earth dam stands at a hydraulic height of 21 feet and has a storage capacity of 164 acre-feet. With a surface area of 8.4 acres and a drainage area of 0.3 square miles, this structure plays a crucial role in managing stormwater and reducing the risk of flooding in the surrounding area.
Owned privately, the Tukwila South Project South Pond is regulated and permitted by the Washington Department of Ecology. Its satisfactory condition assessment in 2012 and low hazard potential attest to its reliability in protecting the community from potential flood events. Situated in a strategic location with a maximum discharge capacity of 119 cubic feet per second, this dam serves as a vital piece of infrastructure in the region's water resource management and climate resilience efforts.
With its primary purpose being flood risk reduction, the Tukwila South Project South Pond plays a significant role in safeguarding the community from the impacts of extreme weather events. As part of a comprehensive flood mitigation strategy, this earth dam contributes to maintaining the safety and security of residents in the area. Supported by state regulatory agencies and inspection protocols, this infrastructure reflects a commitment to sustainable water resource management and climate adaptation in the face of changing environmental conditions.
Year Completed |
2011 |
Dam Length |
1725 |
River Or Stream |
Offstream |
Primary Dam Type |
Earth |
Surface Area |
8.4 |
Hydraulic Height |
21 |
Drainage Area |
0.3 |
Nid Storage |
164 |
Structural Height |
21 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
21 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Mill Creek Near Mouth At Orillia
|
44cfs |
Spring Brook Creek At Orillia
|
7cfs |
Mill Creek At Earthworks Park At Kent
|
8cfs |
Duwamish River At Golf Course At Tukwila
|
6700cfs |
Cedar River At Renton
|
5160cfs |
Green River Near Auburn
|
10100cfs |
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
|
Tukwila South Project South Pond
Lake Fenwick Trail Kent