Thompson Falls - Dry Channel Dam Reservoir Report

Last Updated: December 24, 2025

Thompson Falls - Dry Channel Dam is a captivating hydroelectric structure located in Sanders County, Montana, along the Clark Fork River and Pend Oreille River.


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Summary

Built in 1915, this gravity dam stands at a height of 43 feet and has a length of 448.83 feet, providing crucial water storage with a normal capacity of 14,970 acre-feet and a maximum capacity of 24,450 acre-feet. The dam's primary purpose is hydroelectric power generation and it is owned and operated by a private entity.

Managed by the Federal Energy Regulatory Commission, Thompson Falls - Dry Channel Dam is equipped with an uncontrolled spillway and 12 other controlled outlet gates to regulate water flow. Despite its low hazard potential, the dam's risk assessment is rated as moderate, indicating a need for ongoing risk management measures. The dam's inspection frequency is set at three years, with the last inspection conducted in August 2018.

The dam's strategic location and historical significance make it a noteworthy site for water resource and climate enthusiasts. With its blend of engineering excellence and environmental impact, Thompson Falls - Dry Channel Dam serves as a critical infrastructure for power generation and water management in the region, highlighting the intersection of human ingenuity and natural resources in sustainable development efforts.

Year Completed

1915

Dam Length

448.83

Dam Height

43

River Or Stream

Clark Fork River, Pend Oreille

Primary Dam Type

Gravity

Surface Area

1580

Hydraulic Height

43

Drainage Area

21113

Nid Storage

24450

Structural Height

47

Outlet Gates

Other Controlled - 12

Hazard Potential

Low

Nid Height

47
       
Seasonal Comparison

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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.