Lost Lake West Reservoir Report

Last Updated: December 4, 2025

Lost Lake West, located in Alpine County, California, is a key water resource infrastructure managed by a public utility agency.


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Summary

Built in 1925, this earth dam stands at 21 feet tall and serves primarily for irrigation and water supply purposes, with a storage capacity of 140 acre-feet. The dam overlooks Lost Creek and has a low hazard potential, deemed satisfactory in condition as of the last assessment in 2017.

Managed by the Department of Water Resources and regulated by the Safety of Dams agency, Lost Lake West plays a crucial role in water management in the region. With its strategic location in Mesa Vista and proximity to the Lost Creek, this dam ensures the steady supply of water for agricultural and municipal needs. Despite its age, the structure appears to be well-maintained and regularly inspected, meeting state permitting and enforcement requirements.

For water resource and climate enthusiasts, Lost Lake West offers a glimpse into the intricate network of dams that support California's water infrastructure. Its historical significance, combined with its functional role in water supply, makes it a notable site for understanding the intersection of water management, engineering, and environmental stewardship in the face of changing climate conditions. As a vital piece of the puzzle in ensuring water security for the region, Lost Lake West stands as a testament to the ongoing efforts to manage and adapt to the challenges posed by a changing climate.

Year Completed

1925

Dam Length

200

Dam Height

21

River Or Stream

Lost Creek

Primary Dam Type

Earth

Surface Area

12

Hydraulic Height

17.8

Drainage Area

0.09

Nid Storage

140

Hazard Potential

Low

Nid Height

21
       
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.