Lewiston Reservoir Report

Last Updated: December 5, 2025

Lewiston is a small community in California that has a rich history dating back to the Gold Rush era.


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Summary

With a population of just over 1,000 people, the town is known for its beautiful natural surroundings, hydrology, and agricultural production. The Trinity River runs through the town, providing a reliable source of water for irrigation and recreational activities. The area is also known for its snowpack providers, which contribute to the local ecosystem and provide support for agriculture. Lewiston is home to a number of farms and ranches that produce a variety of crops, including apples, pears, and vegetables. Recreational activities in the area include fishing, hunting, hiking, and camping, making Lewiston a popular destination for outdoor enthusiasts. Overall, Lewiston is a unique and vibrant community that offers a wide range of experiences for residents and visitors alike.

Reservoir Details

Storage 24hr Change -2.81%
Percent of Normal 96%
Minimum 13,197.0 acre-ft
2011-07-05
Maximum 15,161.0 acre-ft
2018-07-28
Average 14,107 acre-ft
Nid_Height 91
Hydraulic_Height 73
Primary_Dam_Type Earth
Drainage_Area 719
Year_Completed 1963
Dam_Height 73
Structural_Height 91
Surface_Area 750
Nid_Storage 14660
River_Or_Stream TRINITY RIVER
Dam_Length 745
Hazard_Potential High
       
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.