H&S Bosma Consolidated Lagoon No 4 Reservoir Report
Last Updated: December 13, 2025
H&S Bosma Consolidated Lagoon No 4, also known as Liberty Acres Lagoon 4 Ab, is a private water resource structure located in Yakima, Washington.
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Summary
Managed and regulated by the Washington Dept of Ecology, this offstream earth dam stands at a hydraulic height of 6 feet and was completed in 2000. With a storage capacity of 16 acre-feet and a primary purpose classified as "Other," this lagoon serves an essential role in water management in the region.
Despite its relatively small size, H&S Bosma Consolidated Lagoon No 4 poses a significant hazard potential, with a fair condition assessment as of the last inspection in October 2015. The inspection frequency for this structure is set at 5 years, highlighting the importance of regular monitoring and maintenance to ensure its continued safe operation. While no emergency action plan (EAP) or inundation maps are reported to be in place, the lagoon meets regulatory guidelines and plays a crucial role in the water infrastructure of the area.
For water resource and climate enthusiasts, H&S Bosma Consolidated Lagoon No 4 provides an intriguing case study in private water management and regulatory oversight. With its modest size and significant hazard potential, this earth dam serves as a reminder of the complex challenges and responsibilities involved in maintaining safe and efficient water infrastructure. As the lagoon continues to be monitored and regulated by state authorities, its role in the local ecosystem and water supply remains a focal point for ongoing conservation efforts.
Year Completed |
2000 |
River Or Stream |
Offstream |
Primary Dam Type |
Earth |
Hydraulic Height |
6 |
Nid Storage |
16 |
Structural Height |
6 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
6 |
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.
H&S Bosma Consolidated Lagoon No 4