Isabel Lake No. 1 Reservoir Report

Last Updated: December 5, 2025

Isabel Lake No.


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Summary

1, located in Santa Clara, California, serves as a vital water supply resource for the region since its completion in 1948. This private earth dam stands at 23 feet high and has a storage capacity of 435 acre-feet, providing irrigation, recreation, and water supply purposes. Surrounded by the scenic Tr Isabel Creek, this dam plays a crucial role in water management and conservation efforts in the area.

With a low hazard potential and a satisfactory condition assessment as of September 2017, Isabel Lake No. 1 is regulated by the California Department of Water Resources for safety compliance. The dam's last inspection in November 2020 ensures its structural integrity and readiness to withstand potential emergencies. Despite its age, the dam continues to meet guidelines and serves as an essential component of the local water infrastructure.

In the realm of water resource and climate enthusiasts, Isabel Lake No. 1 stands out as a testament to sustainable water management practices. Its role in providing essential services while maintaining safety standards reflects the importance of responsible stewardship of water resources in California. As a key player in the region's water supply network, this dam embodies the intersection of nature, engineering, and conservation in safeguarding water for future generations.

Year Completed

1948

Dam Length

990

Dam Height

23

River Or Stream

Tr Isabel Creek

Primary Dam Type

Earth

Surface Area

46

Hydraulic Height

18.5

Nid Storage

435

Hazard Potential

Low

Nid Height

23
       
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.