Seattle City Volunteer Park Reservoir Reservoir Report

Last Updated: December 15, 2025

The Seattle City Volunteer Park Reservoir, located within the Seattle city limits in King County, Washington, serves as a crucial water supply structure for the area.


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Summary

Completed in 1901, this Earth-type dam stands at a hydraulic height of 35 feet and a structural height of 20 feet, with a length of 790 feet and a storage capacity of 66 acre-feet. The reservoir covers a surface area of 3.1 acres and is regulated by the Washington Department of Ecology, ensuring its safe operation and maintenance.

With a high hazard potential but a satisfactory condition assessment as of April 2021, the Volunteer Park Reservoir is regularly inspected and maintained to meet state regulatory standards. The dam's emergency action plan was last revised in April 2021, indicating a commitment to preparedness and risk management. In case of any potential risks or emergencies, the reservoir is equipped with contact information for quick response and mitigation measures.

As a vital component of the local water supply infrastructure, the Seattle City Volunteer Park Reservoir represents a historic and essential resource for the community. Its location near Lake Union and offstream river systems underscores its significance in providing water for residents and businesses in the region. With ongoing monitoring and adherence to state regulations, this reservoir plays a key role in ensuring water security and resilience in the face of changing climate conditions.

Year Completed

1901

Dam Length

790

River Or Stream

Tr-Lake Union-Offstream

Primary Dam Type

Earth

Surface Area

3.1

Hydraulic Height

35

Nid Storage

66

Structural Height

20

Hazard Potential

High

Foundations

Soil

Nid Height

35
       
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.