Lahontan Reservoir Report

Last Updated: December 22, 2025

Lahontan, located in Fallon, Nevada, is a federal-owned dam designed by the Bureau of Reclamation and completed in 1915 with the primary purpose of flood risk reduction.


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Summary

It stands as an earth dam with a height of 120 feet and a hydraulic height of 115 feet, providing maximum storage capacity of 422,800 acre-feet. The dam also serves other purposes such as hydroelectric power generation, irrigation, and recreation, making it a vital water resource in the region.

With a hazard potential rated as high and a moderate risk assessment score of 3, Lahontan is a critical infrastructure that requires regular inspections and maintenance by the Bureau of Reclamation. The dam has a spillway width of 400 feet and associated structures for controlled water release, ensuring safety during high water events. While the condition assessment is currently not available, Lahontan's emergency action plan was last revised in 2017, showcasing the ongoing efforts to enhance its resilience to potential risks and emergencies.

As a key feature along the Carson River, Lahontan plays a significant role in managing water resources and mitigating flood risks in Churchill County. Its historical significance, coupled with its multi-purpose functionality, highlights the importance of sustainable water management practices and the need for continued monitoring and maintenance to ensure the safety and reliability of this essential infrastructure for the community and the environment.

Years Modified

1985 - Structural

Year Completed

1915

Dam Length

1915

Dam Height

120

River Or Stream

CARSON RIVER

Primary Dam Type

Earth

Surface Area

15000

Hydraulic Height

115

Drainage Area

1903

Nid Storage

422800

Structural Height

140

Outlet Gates

Needle - 1, Other Controlled - 2, Valve - 2

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

140
       
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.