Seven Oaks Dam Reservoir Report

Last Updated: December 5, 2025

The Seven Oaks Dam is a concrete gravity dam located in San Bernardino County, California.


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Summary

Built in 1999, it stands at 550 feet tall and spans 2,200 feet across the Santa Ana River. The dam was constructed to protect the cities of San Bernardino and Riverside from severe flooding. The hydrology of the region is heavily influenced by snowpack, which is the primary source of surface water for the Santa Ana River. The dam captures water from the river during wet seasons and releases it during dry seasons to support agricultural and recreational activities downstream. The dam has a capacity of 182,000 acre-feet and can hold up to 6.4 billion gallons of water. The area around the Seven Oaks Dam has become a popular destination for hiking, fishing, and other outdoor activities.

Reservoir Details

Storage 24hr Change -0.04%
Percent of Normal 100%
Minimum 2,122.74 acre-ft
2007-09-04
Maximum 2,310.89 acre-ft
2019-03-22
Average 2,160 acre-ft
Dam_Height 550
Hydraulic_Height 520
Drainage_Area 177
Year_Completed 1999
Nid_Storage 145600
Surface_Area 780
River_Or_Stream Santa Ana Riv
Dam_Length 2980
Hazard_Potential High
Primary_Dam_Type Rockfill
Nid_Height 550
       
Seasonal Comparison
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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.