Santiago Creek Reservoir Report

Last Updated: December 5, 2025

Santiago Creek, also known as Irvine Lake, is a vital water resource located in Orange, California.


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Summary

Owned by a Public Utility, this reservoir serves as a primary water supply for irrigation and general water needs in the region. The dam, completed in 1933, stands at a height of 136 feet and has a storage capacity of 25,000 acre-feet.

With a drainage area of 63.1 square miles, Santiago Creek plays a crucial role in managing water flow and storage in the area. However, recent inspections have raised concerns about its condition, with a hazard potential rated as high and a poor condition assessment. The dam is under state regulation and inspection, highlighting the importance of ensuring its safety and functionality for the community.

As a popular destination for water resource and climate enthusiasts, Santiago Creek faces challenges that require ongoing monitoring and maintenance to mitigate risks and ensure its continued operation. With state agencies overseeing its regulation, inspection, and enforcement, efforts are being made to address the dam's poor condition and high hazard potential. As stewards of this essential water source, it is crucial to prioritize the safety and sustainability of Santiago Creek for future generations.

Year Completed

1933

Dam Length

1425

Dam Height

136

River Or Stream

Santiago Creek

Primary Dam Type

Earth

Surface Area

650

Hydraulic Height

120

Drainage Area

63.1

Nid Storage

25000

Hazard Potential

High

Nid Height

136
       
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.