Orchard Estates Retarding Basin Reservoir Report

Last Updated: December 5, 2025

The Orchard Estates Retarding Basin in Tustin, California, is a crucial structure owned by the local government to manage flood risk reduction in the area.


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Summary

Completed in 1999, this earth dam stands at 21 feet high and has a storage capacity of 138 acre-feet. Situated along Tr Rattlesnake Can, this basin covers a surface area of 11 acres and serves a drainage area of 0.63 square miles.

Maintained by the Department of Water Resources and Safety of Dams, the Orchard Estates Retarding Basin has a high hazard potential but is currently in satisfactory condition as per the last assessment in September 2017. With a regular inspection frequency of once a year, this structure is regulated by the state and has all necessary permits for operation. In case of emergencies, the basin is equipped with an Emergency Action Plan (EAP) to ensure the safety of the surrounding community.

Located in Orange County, California, the Orchard Estates Retarding Basin plays a crucial role in protecting the area from potential flood risks. With its strategic design and efficient management, this structure stands as a testament to the proactive approach taken by local authorities to safeguard water resources and address climate challenges in the region.

Year Completed

1999

Dam Length

810

Dam Height

21

River Or Stream

Tr Rattlesnake Can

Primary Dam Type

Earth

Surface Area

11

Hydraulic Height

13

Drainage Area

0.63

Nid Storage

138

Hazard Potential

High

Nid Height

21
       
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.