Laguna Regulating Basin

Laguna Regulating Basin is an earth dam located in Los Angeles County, California, built in 1970. It carries a Significant hazard potential classification and has a satisfactory condition assessment.

About Laguna Regulating Basin

The primary purpose of Laguna Regulating Basin is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Los Angeles County Department Of Public Works (local government). It impounds the Laguna Wash.

The dam stands 43 feet tall and stretches 380 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 310 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1970, the structure is well into its service life at over 50 years old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 11/19/2025.

At 43 feet, this dam is taller than 89% of dams nationwide.

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Significant HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateCalifornia
CountyLos Angeles
River/StreamLaguna Wash
Coordinates34.06390, -118.16420

Physical Characteristics

Dam TypeEarth
NID Height43 ft
Dam Height43 ft
Dam Length380 ft
Year Completed1970 (56 years old)

Storage & Hydraulics

NID Storage310 acre-ft
Max Storage310 acre-ft
Surface Area12 acres
Drainage Area5 sq mi

Ownership & Safety

PurposeFlood Risk Reduction
OwnerLos Angeles County Department Of Public Works
Owner TypeLocal Government
Hazard ClassificationSignificant
Condition AssessmentSatisfactory
Last Inspection11/19/2025
Emergency Action PlanYes

Identifiers

NID IDCA00203
Federal IDCA00203
More InfoState Dam Safety Program

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