Box Canyon Forebay Dam Reservoir Report

Last Updated: December 14, 2025

Located in Metaline, Washington, the Box Canyon Forebay Dam is a concrete gravity dam primarily used for hydroelectric purposes.


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Summary

Completed in 1955, this dam stands at a height of 32 feet and spans a length of 50 feet, with a storage capacity of 36 acre-feet. Situated on the Pend Oreille River, this structure is managed by a public utility and falls under the jurisdiction of the Federal Energy Regulatory Commission.

With a hazard potential rated as low and a moderate risk assessment, the Box Canyon Forebay Dam is inspected every three years to ensure its structural integrity and safety. The dam features an uncontrolled spillway with a width of 42 feet and is associated with two other structures in the region. Despite not being regulated by the state, the Federal Energy Regulatory Commission oversees the operations, inspections, and design of this hydroelectric facility.

Water resource and climate enthusiasts will find the Box Canyon Forebay Dam a fascinating example of sustainable energy generation in the beautiful landscape of Pend Oreille, Washington. This multi-arch dam, built on a rock foundation, plays a crucial role in harnessing the power of the Pend Oreille River for electricity production while minimizing environmental impact. Its strategic location and efficient design make it a noteworthy asset in the region's water resource management infrastructure.

Year Completed

1955

Dam Length

50

Dam Height

32

River Or Stream

Pend Oreille River

Primary Dam Type

Concrete

Surface Area

2.4

Drainage Area

24900

Nid Storage

36

Hazard Potential

Low

Foundations

Rock

Nid Height

32
       
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.