West Valley Reservoir Report

Last Updated: December 5, 2025

West Valley, also known as West Valley Reservoir, is a critical water resource located in Modoc County, California.


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Summary

Owned by a public utility, this reservoir plays a vital role in providing water for irrigation and general water supply purposes. Completed in 1936, the dam stands at a height of 65 feet and has a storage capacity of 23,000 acre-feet, serving the local community in Likely, California.

Managed by the California Department of Water Resources (DWR) and regulated by the Safety of Dams program, West Valley Dam is situated on the West Valley Creek. With a surface area of 1050 acres and a drainage area of 136 square miles, the reservoir has a high hazard potential but is currently in satisfactory condition as of the last assessment in 2017. The dam underwent its last inspection in October 2020, with regular inspections conducted to ensure its safety and integrity.

Despite its age, West Valley Dam continues to be a crucial water storage and supply infrastructure in the region. With enforcement, permitting, and inspection protocols in place, the reservoir remains a reliable resource for the community, highlighting the importance of sustainable water management practices in the face of climate change challenges.

Year Completed

1936

Dam Length

305

Dam Height

65

River Or Stream

West Valley Cr

Primary Dam Type

Earth

Surface Area

1050

Hydraulic Height

53.7

Drainage Area

136

Nid Storage

23000

Hazard Potential

High

Nid Height

65
       
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.