Sly Creek Reservoir Report

Last Updated: December 5, 2025

Sly Creek Reservoir is a man-made lake located in the northern Sierra Nevada mountain range of California.


°F

°F

mph

Wind

%

Humidity

Summary

The history of the reservoir began in 1960 when the Feather River Hydroelectric Project was constructed. The reservoir is primarily used to generate hydroelectric power, store water for downstream agricultural and municipal use, and provide recreational opportunities such as fishing, boating, and camping. The Sly Creek watershed, which feeds the reservoir, is predominantly forested and consists of granite outcrops and meadows. The watershed is also home to several important plant and animal species, including the Pacific fisher and northern goshawk. The reservoir’s primary source of water is from snowpack, which typically begins to melt in April and peaks in May or June. The reservoir is a vital component of California’s water supply system and plays an important role in meeting the state’s water demands.

Reservoir Details

Storage 24hr Change -1.58%
Percent of Normal 192%
Minimum 9,540.0 acre-ft
2010-01-04
Maximum 64,470.0 acre-ft
2005-05-30
Average 24,100 acre-ft
Dam_Height 299
Hydraulic_Height 260
Drainage_Area 24
Year_Completed 1961
Nid_Storage 65650
River_Or_Stream Lost Creek
Structural_Height 289
Primary_Dam_Type Earth
Foundations Rock
Surface_Area 619
Hazard_Potential High
Dam_Length 1200
Nid_Height 299
       
Seasonal Comparison
Storage Levels
Pool Elevation Levels
Top Conserv Storage Levels
Inflow 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.