Cow Palace Lagoon 1 Reservoir Report
Last Updated: December 13, 2025
Cow Palace Lagoon 1, also known as Dolsen Pond Dam, is a privately owned earth dam located in Yakima, Washington.
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Summary
Constructed in 2000, this dam serves a primary purpose of "Other" and has a hydraulic height of 12 feet, a structural height of 12 feet, and a length of 750 feet. The dam has a storage capacity of 33 acre-feet and a surface area of 2.7 acres, with a drainage area of 0.01 square miles.
With a significant hazard potential and a fair condition assessment as of June 2017, Cow Palace Lagoon 1 is regulated by the Washington Department of Ecology. The dam has been inspected every 5 years, with the most recent inspection conducted in June 2017. In 2012, hydraulic modifications were made to the dam. Despite its fair condition, the dam poses a significant risk, highlighting the importance of ongoing monitoring and maintenance to ensure the safety and integrity of this water resource in the region.
Years Modified |
2012 - Hydraulic |
Year Completed |
2000 |
Dam Length |
750 |
River Or Stream |
Offstream |
Primary Dam Type |
Earth |
Surface Area |
2.7 |
Hydraulic Height |
12 |
Drainage Area |
0.01 |
Nid Storage |
33 |
Structural Height |
12 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
12 |
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 1