Diederich Reservoir Reservoir Report

Last Updated: December 5, 2025

Diederich Reservoir in Glendale, California is a vital offstream water supply facility owned and regulated by the local government.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1950, this Earth dam stands at 60 feet tall with a storage capacity of 174 acre-feet, serving as a critical water resource for the region. The reservoir covers 7 acres and plays a key role in water management for the area.

With a high hazard potential, Diederich Reservoir undergoes regular inspections to ensure its structural integrity and overall safety. The dam is classified as satisfactory in condition, with the last assessment conducted in September 2017. In the event of an emergency, an emergency action plan is in place, with the most recent revision made in January 2021. This reservoir is a key component in ensuring water supply reliability and security for the community, highlighting the importance of diligent maintenance and oversight.

Situated in Los Angeles County, Diederich Reservoir is a key component of the water infrastructure in the area, providing essential storage capacity for water supply purposes. With its strategic location and significance in the region, this reservoir serves as a critical resource for managing water resources and climate-related challenges in the area. The careful monitoring and maintenance of Diederich Reservoir underscore the commitment to safeguarding this essential water supply source for the community.

Year Completed

1950

Dam Length

100

Dam Height

60

River Or Stream

Offstream

Primary Dam Type

Earth

Surface Area

7

Hydraulic Height

56

Nid Storage

174

Hazard Potential

High

Nid Height

60
       
Seasonal Comparison

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.