Fourmile Lake Reservoir Report

Last Updated: December 5, 2025

Fourmile Lake, located in Klamath, Oregon, is a captivating water resource managed by the Bureau of Reclamation for flood risk reduction and irrigation purposes.


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Summary

This rockfill dam, completed in 1921, stands at a height of 25 feet and has a storage capacity of 15,800 acre-feet. The dam spans 660 feet in length and has a spillway width of 60 feet, ensuring controlled water release in times of high discharge.

With a hazard potential rated as low and a risk assessment indicating a very high risk level, Fourmile Lake poses both a practical solution for flood risk management and a challenge for effective risk management strategies. The lake covers a surface area of 962 acres and is fed by Fourmile Creek, providing important irrigation water for the surrounding area. Despite its age, the dam remains structurally sound, with regular inspections conducted by the Bureau of Reclamation to ensure its continued safety and functionality.

For water resource and climate enthusiasts, Fourmile Lake offers a fascinating example of sustainable water management and infrastructure development in Oregon. The dam's construction and operation by the Bureau of Reclamation showcase the importance of proactive flood risk reduction measures in a region prone to high discharges. As a key player in the water resource landscape, Fourmile Lake stands as a testament to the balance between harnessing natural resources for human benefit while mitigating potential risks to ensure long-term environmental and community resilience.

Year Completed

1921

Dam Length

660

Dam Height

25

River Or Stream

FOURMILE CREEK

Primary Dam Type

Rockfill

Surface Area

962

Hydraulic Height

18

Drainage Area

15

Nid Storage

15800

Structural Height

25

Hazard Potential

Low

Foundations

Rock

Nid Height

25
       
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.