Youngs Lake Outlet Dam Reservoir Report

Last Updated: December 15, 2025

Youngs Lake Outlet Dam, also known as South Dam, is a vital structure owned by the local government in Auburn, Washington.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1921, this earth dam on Little Soos Creek stands at a height of 30 feet with a hydraulic height of 33 feet, serving primarily for water supply purposes. With a storage capacity of 35,450 acre-feet and a drainage area of 2.19 square miles, the dam has a significant impact on the surrounding environment.

The dam's condition assessment in June 2019 deemed it satisfactory, but its hazard potential is classified as high. The last inspection highlighted its structural integrity, with an inspection frequency of 5 years. The emergency action plan (EAP) for the dam was last revised in December 2020, ensuring preparedness in case of any unforeseen events. The location in King County, Washington, and the close proximity to the Seattle District underline the importance of this dam in the region's water resource management and climate resilience efforts.

Youngs Lake Outlet Dam plays a crucial role in the water supply infrastructure of Auburn, Washington, ensuring a reliable source of water for the community. Its historical significance, combined with its high hazard potential, emphasizes the need for regular inspections and maintenance to uphold its structural integrity and safeguard against potential risks. As climate change impacts continue to affect water resources, the dam's management by the Washington Department of Ecology underscores the importance of proactive measures to address evolving challenges in water resource management and climate adaptation.

Year Completed

1921

Dam Length

1450

River Or Stream

Little Soos Creek

Primary Dam Type

Earth

Surface Area

690

Hydraulic Height

33

Drainage Area

2.19

Nid Storage

35450

Structural Height

30

Hazard Potential

High

Foundations

Soil

Nid Height

33
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.