New Melones Reservoir Reservoir Report

Last Updated: December 5, 2025

New Melones Reservoir is located in Calaveras and Tuolumne counties, California.


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Summary

It was created in 1979 by the construction of the New Melones Dam on the Stanislaus River. The reservoir has a capacity of 2.4 million acre-feet and is an important source of water for hydroelectric power generation, agriculture, and recreation. The hydrology of the reservoir is influenced by the snowpack from the Sierra Nevada Mountains, which provides water for the river and reservoir during the dry months. The surface flow providers for the reservoir include the Stanislaus, Tuolumne, and Calaveras rivers. The reservoir is used for irrigation of crops such as almonds, grapes, and citrus fruits, as well as for recreational activities such as fishing, boating, and camping. The reservoir also provides habitat for various fish, including the endangered Chinook salmon and the steelhead trout.

Reservoir Details

Storage 24hr Change -0.07%
Percent of Normal 148%
Minimum 264,401.0 acre-ft
2015-11-07
Maximum 2,356,700.0 acre-ft
2006-06-15
Average 1,333,930 acre-ft
Nid_Height 625
Hydraulic_Height 614
Drainage_Area 897
Year_Completed 1979
Dam_Height 578
Structural_Height 625
River_Or_Stream STANISLAUS RIVER
Primary_Dam_Type Rockfill
Surface_Area 13450
Hazard_Potential High
Nid_Storage 2870000
Dam_Length 1560
       
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.