Lake Chelan At Chelan Reservoir Report

Last Updated: December 13, 2025

Lake Chelan is a natural lake located in Chelan, Washington, and is approximately 50.5 miles long.


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Summary

The lake was formed over 10,000 years ago by a glacier and has a maximum depth of 1,486 feet. Lake Chelan is fed by several streams, including the Stehekin River, and is the main source of water for the surrounding area. The lake's hydrology is unique, as it is considered a closed basin, meaning it has no outlet to the sea. The lake's surface flow is regulated by the Chelan River Dam, which produces hydroelectric power. Snowpack providers for the lake are the North Cascades and the Chelan Mountains. The lake supports agricultural activities, including fruit orchards and vineyards. Recreation activities, such as boating, swimming, and fishing, are also popular in the area.

Reservoir Details

Elevation Of Reservoir Water Surface Above Datum, Ft 24hr Change 0.08%
Percent of Normal 100%
Minimum 1,082.68 ft
2008-03-14
Maximum 1,100.04 ft
2012-07-27
Average 1,092 ft
Dam_Height 33
Hydraulic_Height 57
Drainage_Area 952
Year_Completed 1927
Nid_Storage 676100
Hazard_Potential Significant
Structural_Height 66
River_Or_Stream Chelan River
Foundations Rock, Soil
Surface_Area 32980
Outlet_Gates Slide (sluice gate) - 1, Tainter (radial) - 8
Dam_Length 490
Primary_Dam_Type Gravity
Nid_Height 66
       
Seasonal Comparison
Elevation Of Reservoir Water Surface Above Datum, Ft Levels

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.