Diemer No. 8 Reservoir Report

Last Updated: December 5, 2025

Diemer No.


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Summary

8 is a significant dam located in Yorba Linda, California, with a primary purpose of water supply. Completed in 1968, this offstream dam stands at an impressive height of 172 feet and has a storage capacity of 18 acre-feet. Managed by a public utility, Diemer No. 8 is regulated by the California Department of Water Resources (DWR) for safety compliance and undergoes regular inspections to ensure its satisfactory condition.

This dam plays a crucial role in providing water to the surrounding area, with a drainage area of 0.01 square miles. Despite its significant hazard potential, the condition assessment of Diemer No. 8 remains satisfactory, with the last inspection conducted in August 2020. The dam's emergency action plan (EAP) was last revised in January 2018, ensuring that appropriate measures are in place in case of an emergency. With its impressive structure and essential function in water resource management, Diemer No. 8 stands as a testament to California's commitment to ensuring a reliable water supply for its residents.

Year Completed

1968

Dam Length

1004

Dam Height

172

River Or Stream

Offstream

Primary Dam Type

Other

Surface Area

1

Hydraulic Height

171.2

Drainage Area

0.01

Nid Storage

18

Hazard Potential

Significant

Nid Height

172
       
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.