Whitefish Sewage Lagoon Reservoir Report

Last Updated: December 5, 2025

The Whitefish Sewage Lagoon in Kalispell, Montana, is a crucial water resource infrastructure owned by the local government and regulated by the Montana Department of Natural Resources and Conservation (DNRC).


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Summary

Completed in 1962, this Earth-type dam on the Whitefish River serves as a storage facility with a normal capacity of 90 acre-feet and a maximum storage of 106 acre-feet. Despite its low hazard potential, the dam's condition is currently not rated, prompting the need for further inspection and assessment.

Located in Flathead County, Montana, the Whitefish Sewage Lagoon plays a vital role in wastewater management and environmental protection in the region. With a dam height of 9 feet and a length of 3200 feet, this facility serves as a key component in the treatment and disposal of sewage. While the dam has not been modified in recent years and lacks specific hazard assessment and emergency preparedness measures, its operational significance underscores the importance of regular maintenance and monitoring to ensure public safety and water quality.

In the context of climate change and water resource management, the Whitefish Sewage Lagoon represents a critical infrastructure asset that requires ongoing attention and investment. As water resource and climate enthusiasts, it is essential to advocate for sustainable practices and policies that support the proper operation and maintenance of such facilities to safeguard both the environment and public health. With an emphasis on risk assessment, emergency preparedness, and regulatory compliance, the Whitefish Sewage Lagoon serves as a poignant example of the intersection between water resources, infrastructure resilience, and climate adaptation in a changing world.

Year Completed

1962

Dam Length

3200

Dam Height

9

River Or Stream

WHITEFISH RIVER

Primary Dam Type

Earth

Hydraulic Height

9

Nid Storage

106

Hazard Potential

Low

Nid Height

9
       
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.