Declez Retention Reservoir Report

Last Updated: December 5, 2025

Declez Retention in Riverside, California, is a local government-owned structure designed for flood risk reduction along the Tr San Sevaine Creek.


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Summary

Completed in 1984, this earth dam stands at a height of 30 feet with a hydraulic height of 23 feet, providing a storage capacity of 331 acre-feet. The dam has a length of 1500 feet and a surface area of 21 acres, serving as a crucial infrastructure for water resource management in the region.

With a high hazard potential, Declez Retention undergoes regular inspections to ensure its structural integrity. The last assessment in September 2017 deemed its condition as satisfactory, with a hazard potential rating of high. The Emergency Action Plan (EAP) for the dam was last reviewed in October 2019, highlighting the importance of preparedness and risk management measures in case of emergencies. Mark Takano, a Congressman representing the area, is involved in overseeing the safety and regulatory aspects of the dam.

As a vital component in the flood risk reduction strategy for Glen Avon Heights, Declez Retention plays a crucial role in safeguarding the community from potential disasters. Its strategic location and design make it an essential asset for water resource management and climate resilience efforts in the region, underlining the importance of proactive maintenance and adherence to safety protocols to ensure its continued effectiveness in mitigating flood risks.

Year Completed

1984

Dam Length

1500

Dam Height

30

River Or Stream

Tr San Sevaine Cr

Primary Dam Type

Earth

Surface Area

21

Hydraulic Height

23

Nid Storage

331

Hazard Potential

High

Nid Height

30
       
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.