Lower Van Norman Bypass Reservoir Report

Last Updated: December 5, 2025

The Lower Van Norman Bypass is a key water infrastructure located in Granada Hills, California, designed primarily for hydroelectric power generation and water supply purposes.


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Summary

Completed in 1970, this earth dam stands at a height of 78 feet and has a hydraulic height of 69.3 feet, with a storage capacity of 240 acre-feet. Situated offstream, this structure serves to manage water resources in the region, with a drainage area of 0.03 square miles and a surface area of 12 acres.

Owned and regulated by the local government, the Lower Van Norman Bypass is under the oversight of the California Department of Water Resources (DWR) and the Safety of Dams agency. With a low hazard potential and satisfactory condition assessment as of September 2017, this dam plays a critical role in the water management system of Los Angeles County. Its last inspection in November 2020 revealed no significant issues, indicating a well-maintained and functional structure.

For enthusiasts interested in water resources and climate, the Lower Van Norman Bypass represents a vital piece of infrastructure contributing to the sustainable use of water in the region. With its dual purpose of hydroelectric power generation and water supply, this earth dam serves as a testament to California's commitment to efficient water management and renewable energy production. As it continues to play a crucial role in the local water infrastructure, ensuring its ongoing maintenance and regulatory compliance remains essential for the community's water security and environmental resilience.

Year Completed

1970

Dam Length

600

Dam Height

78

River Or Stream

Offstream

Primary Dam Type

Earth

Surface Area

12

Hydraulic Height

69.3

Drainage Area

0.03

Nid Storage

240

Hazard Potential

Low

Nid Height

78
       
Seasonal Comparison

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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.