Blue Lake Dam Okanogan Co Reservoir Report

Last Updated: December 13, 2025

Blue Lake Dam in Okanogan County, Washington, is a state-owned structure built in 1923 primarily for recreational purposes.


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Summary

Situated in the picturesque city of Loomis, the dam spans 1500 feet in length and boasts a hydraulic height of 32 feet. With a normal storage capacity of 4416 acre-feet and a surface area of 160 acres, the dam serves as a vital resource for the surrounding community and visitors alike.

Managed by the Washington Department of Ecology, Blue Lake Dam is classified as a rockfill structure with a low hazard potential. Despite not having a formal condition assessment, the dam's state jurisdiction ensures regular inspections, permitting, and enforcement. The dam's location on Tr-Sinlahekin Creek offers a serene setting for outdoor enthusiasts, while its historical significance as a key recreational site in the region adds to its allure.

As climate change continues to impact water resources, the conservation and maintenance of dams like Blue Lake Dam are crucial for sustaining the local ecosystem and recreational opportunities. With the support of the state regulatory agency and ongoing monitoring efforts, Blue Lake Dam stands as a testament to the importance of responsible water resource management in Okanogan County and beyond.

Year Completed

1923

Dam Length

1500

River Or Stream

Tr-Sinlahekin Creek

Primary Dam Type

Rockfill

Surface Area

160

Hydraulic Height

32

Drainage Area

10.2

Nid Storage

4416

Structural Height

10

Hazard Potential

Low

Foundations

Soil

Nid Height

32
       
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.