Belfair Wwtp Treated Water Storage Pond Reservoir Report

Last Updated: December 14, 2025

Located in Mason County, Washington, the Belfair Wwtp Treated Water Storage Pond is a vital infrastructure owned by the local government to manage treated water from the Belfair Wastewater Treatment Plant.


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Summary

Completed in 2014, this earth dam structure stands at a hydraulic height of 70 feet and has a storage capacity of 208 acre-feet. With a normal storage level of 159.5 acre-feet and a surface area of 14.41 acres, this pond plays a crucial role in maintaining water resources in the region.

Despite its importance, the Belfair Wwtp Treated Water Storage Pond has been deemed to have a high hazard potential and poor condition assessment. Inspected every five years, the last assessment in May 2018 revealed its deteriorating state. With no Emergency Action Plan (EAP) in place and outdated emergency contact information, there are concerns about its ability to manage potential risks effectively. As climate change continues to impact water resources, the maintenance and improvement of this storage pond are essential to safeguard the community and environment.

As water resource and climate enthusiasts, it is crucial to monitor and advocate for the proper management and maintenance of structures like the Belfair Wwtp Treated Water Storage Pond. With a high hazard potential and poor condition assessment, there is a pressing need for proactive measures to ensure the safety and functionality of this essential infrastructure. By staying informed and advocating for necessary upgrades and improvements, we can help protect the water resources and environment in Mason County, Washington, for future generations.

Year Completed

2014

Dam Length

1700

River Or Stream

Coulter Creek

Primary Dam Type

Earth

Surface Area

14.41

Hydraulic Height

70

Drainage Area

12.7

Nid Storage

208

Structural Height

20

Hazard Potential

High

Nid Height

70
       
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.