Lake Hemet Reservoir Report

Last Updated: December 5, 2025

Lake Hemet, located in Riverside County, California, is a gravity dam constructed in 1895 primarily for water supply purposes, serving irrigation and water supply needs in the region.


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Summary

With a height of 135 feet and a storage capacity of 14,000 acre-feet, the dam stands as a vital infrastructure for managing water resources in the area. The dam is regulated and inspected by the California Department of Water Resources for safety and compliance, ensuring its satisfactory condition for continued operation.

The dam impounds the waters of the Tr San Jacinto River, creating a reservoir with a surface area of 470 acres and a drainage area of 65.8 square miles. Despite its high hazard potential, the dam has been assessed as satisfactory, with an emergency action plan in place to address any potential risks. The surrounding area of Valle Vista benefits from the reservoir's water supply, demonstrating the crucial role Lake Hemet plays in supporting both agricultural and domestic water needs in the region.

With its long history of providing water resources to the community, Lake Hemet stands as a symbol of sustainable water management in California. The dam's strategic location and efficient operation underscore its importance in securing water supply for the area, while its compliance with state regulations and regular inspections ensure the safety and reliability of this critical infrastructure. For water resource and climate enthusiasts, Lake Hemet serves as a fascinating example of how man-made structures can play a pivotal role in shaping the hydrological landscape and supporting environmental sustainability.

Year Completed

1895

Dam Length

324

Dam Height

135

River Or Stream

Tr San Jacinto River

Primary Dam Type

Gravity

Surface Area

470

Hydraulic Height

130

Drainage Area

65.8

Nid Storage

14000

Hazard Potential

High

Nid Height

135
       
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.