Cow Palace Lagoon 2 Reservoir Report
Last Updated: December 13, 2025
Cow Palace Lagoon 2, located in Yakima, Washington, is a privately owned earth dam that was completed in 2017 with a primary purpose of "Other." The dam has a hydraulic height of 28 feet and a storage capacity of 88 acre-feet, with a normal storage level of 75 acre-feet.
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Summary
The structure is regulated by the Washington Department of Ecology and has passed inspections with a satisfactory condition assessment.
Despite being privately owned, Cow Palace Lagoon 2 is subject to state jurisdiction, permitting, inspection, and enforcement. The dam has a high hazard potential, indicating the potential risk to downstream communities in the event of a failure. Emergency action plans are in place, with the last revision in 2017, to ensure proper response and communication in case of an emergency.
As a critical infrastructure component in the region, Cow Palace Lagoon 2 serves as a vital water resource management tool. Water resource and climate enthusiasts will find this dam an intriguing case study in dam construction, regulation, and emergency preparedness within the state of Washington.
Year Completed |
2017 |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
88 |
Hazard Potential |
High |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Granger Drain At Granger
|
13cfs |
Yakima River At Mabton
|
26200cfs |
Yakima River Above Ahtanum Creek At Union Gap
|
29600cfs |
Ahtanum Creek At Union Gap
|
542cfs |
Columbia River Below Priest Rapids Dam
|
103000cfs |
Toppenish Creek Near Fort Simcoe
|
73cfs |
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.
Cow Palace Lagoon 2