Greenhorn Reservoir Report

Last Updated: December 28, 2025

Greenhorn Reservoir, located in Yreka, California, is a vital water resource managed by the local government for water supply and recreation purposes.


°F

°F

mph

Wind

%

Humidity

Summary

The earth dam, completed in 1960, stands at a height of 35 feet and has a storage capacity of 251 acre-feet. Situated on Greenhorn Creek, the reservoir covers an area of 25 acres and serves as a key source of water for the surrounding community.

With a high hazard potential, the dam undergoes regular inspections by the Department of Water Resources to ensure its structural integrity. The latest assessment in September 2017 deemed the dam's condition as satisfactory, providing confidence in its ability to withstand potential risks and emergencies. Despite its critical role in water management, the reservoir also offers recreational opportunities for visitors to enjoy the scenic beauty of the area.

Managed by the Natural Resources Conservation Service, Greenhorn Reservoir plays a crucial role in water supply and environmental conservation efforts in the region. As climate change continues to impact water resources, the sustainable management of reservoirs like Greenhorn becomes increasingly important to ensure the resilience of communities and ecosystems in the face of evolving environmental challenges.

Year Completed

1960

Dam Length

1300

Dam Height

35

River Or Stream

Greenhorn Creek

Primary Dam Type

Earth

Surface Area

25

Hydraulic Height

29.5

Drainage Area

12.1

Nid Storage

251

Hazard Potential

High

Nid Height

35
       
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.