Little Grass Valley Reservoir Report

Last Updated: December 5, 2025

Little Grass Valley is a captivating hydroelectric dam nestled in the scenic Plumas County, California, near the quaint town of Golden Trout Crossing.


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Summary

Built in 1961 by Bechtel, this Earth dam stands at an impressive height of 184 feet, with a hydraulic height of 198 feet and a structural height of 210 feet. The dam's primary purpose is hydroelectric power generation, while also serving irrigation and water supply needs in the region.

With a storage capacity of 94,660 acre-feet and a normal storage of 93,010 acre-feet, Little Grass Valley ensures a reliable water supply for the surrounding area. The dam's controlled spillway, with a width of 80 feet, helps manage potential high-hazard risks associated with the dam. Despite its very high risk assessment, the dam has not undergone a recent condition assessment. However, the Federal Energy Regulatory Commission oversees inspections to ensure the safety and integrity of the structure.

Surrounded by the beauty of the South Fork Feather River and boasting a surface area of 1630 acres, Little Grass Valley is a vital component of California's water resource infrastructure. Its role in providing clean energy and essential water resources underscores the importance of sustainable management practices for water and climate enthusiasts in the region.

Year Completed

1961

Dam Length

840

Dam Height

184

River Or Stream

South Fork Feather River

Primary Dam Type

Earth

Surface Area

1630

Hydraulic Height

198

Drainage Area

25.8

Nid Storage

94660

Structural Height

210

Outlet Gates

Tainter (radial) - 2

Hazard Potential

High

Foundations

Rock

Nid Height

210
       
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.