Grandview Wastewater Lagoon 1 Dam Reservoir Report
Last Updated: December 15, 2025
Grandview Wastewater Lagoon 1 Dam is a significant structure located in Yakima, Washington, along the Yakima River.
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Summary
Completed in 1999, this earth dam stands at a hydraulic height of 10 feet and a length of 2080 feet, with a storage capacity of 66 acre-feet. With the primary purpose of serving as a wastewater containment facility, this dam is state-regulated by the Washington Dept of Ecology, ensuring that it meets all necessary inspection, permitting, and enforcement requirements to maintain its satisfactory condition.
Despite its relatively small drainage area of 0.01 square miles, Grandview Wastewater Lagoon 1 Dam poses a significant hazard potential, emphasizing the importance of regular inspections and emergency preparedness. The dam's condition was last assessed in July 2019 and was found to be satisfactory, indicating that it is currently operating as intended. While there are no associated structures or outlet gates, the dam's proximity to the Yakima River underscores its crucial role in managing water resources in the region. Overall, Grandview Wastewater Lagoon 1 Dam serves as a vital infrastructure for local government in maintaining water quality and environmental protection in the area.
Year Completed |
1999 |
Dam Length |
2080 |
River Or Stream |
Yakima River |
Primary Dam Type |
Earth |
Hydraulic Height |
10 |
Drainage Area |
0.01 |
Nid Storage |
66 |
Structural Height |
10 |
Hazard Potential |
Significant |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Yakima River At Mabton
|
19900cfs |
Granger Drain At Granger
|
13cfs |
Yakima River At Kiona
|
16300cfs |
Columbia River Below Priest Rapids Dam
|
115000cfs |
Yakima River Above Ahtanum Creek At Union Gap
|
11300cfs |
Ahtanum Creek At Union Gap
|
164cfs |
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.
Grandview Wastewater Lagoon 1 Dam