Blue Lake Reservoir Report

Last Updated: December 5, 2025

Blue Lake, located in Lassen, California, is a federal-owned water resource managed by the USDA Forest Service.


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Summary

This earthen dam, completed in 1960, serves multiple purposes including fire protection, stock watering, and small fish pond habitat. With a height of 8 feet and a capacity of 600 acre-feet, the dam plays a crucial role in maintaining water supply for various uses in the region.

Despite its low hazard potential, Blue Lake is categorized as having a very high risk assessment due to its critical importance for water supply and ecological purposes. The controlled spillway, valve outlet gates, and regular inspections ensure the dam's safety and functionality. However, the condition assessment remains unrated as of the last inspection in 2011, highlighting the need for ongoing monitoring and maintenance to mitigate potential risks and ensure long-term sustainability.

As a key feature in the San Francisco District's water infrastructure, Blue Lake serves as a vital resource for the local community and wildlife. Its strategic location and purposeful design make it a significant asset for water management, climate resilience, and ecological conservation efforts in the region.

Year Completed

1960

Dam Length

70

Dam Height

8

Primary Dam Type

Earth

Hydraulic Height

7

Nid Storage

600

Structural Height

8

Outlet Gates

Valve

Hazard Potential

Low

Nid Height

8
       
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.