Matilija Dam Reservoir Report

Last Updated: December 5, 2025

Matilija Dam is a structure located in Ventura County, California.


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Summary

It was built in 1948 primarily to control floods and provide water for agriculture, domestic, and industrial purposes. The dam is 200 feet high and 530 feet wide and has a storage capacity of 7,000 acre-feet. The Matilija Creek watershed covers 114 square miles and is an important source of surface flow and snowpack providers for the surrounding areas. The dam has been a topic of controversy due to the significant amount of sediment build-up behind it and the negative impact on the environment and fish populations. The dam is currently being considered for removal or modification to restore the natural flow of the creek and allow for the revitalization of the ecosystem. The area around the dam is a popular recreational site for hiking, fishing, and camping.

Reservoir Details

Storage 24hr Change None%
Percent of Normal None%
Minimum 784.0 acre-ft
2021-08-29
Maximum 3,488.0 acre-ft
2023-06-04
Average acre-ft
Dam_Height 163
Hydraulic_Height 120
Drainage_Area 55
Year_Completed 1949
Nid_Storage 1800
River_Or_Stream Matilija Creek
Surface_Area 86
Hazard_Potential High
Dam_Length 620
Primary_Dam_Type Arch
Nid_Height 163
       
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.