Shelby Sewage Lagoon Reservoir Report
Nearby: Cowpath Dam Sullivan Dam
Last Updated: December 5, 2025
Located in Toole, Montana, the Shelby Sewage Lagoon is a vital water resource managed by the local government.
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Summary
Built in 1960, this Earth dam stands at 10 feet in height and spans 2000 feet in length, providing a storage capacity of 195 acre-feet. Situated along the TR-MARIAS RIVER, this facility is regulated by the Department of Natural Resources and Conservation (DNRC) in Montana.
Despite its low hazard potential, the Shelby Sewage Lagoon plays a crucial role in managing wastewater and protecting water quality in the region. With state permitting, inspection, and enforcement in place, this facility ensures compliance with environmental regulations. As an essential piece of infrastructure in the area, the lagoon serves its primary purpose effectively while maintaining a condition assessment of "Not Rated." Water resource and climate enthusiasts can appreciate the importance of properly managing and maintaining facilities like the Shelby Sewage Lagoon to safeguard water resources and ecosystems.
Year Completed |
1960 |
Dam Length |
2000 |
Dam Height |
10 |
River Or Stream |
TR-MARIAS RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
10 |
Nid Storage |
195 |
Hazard Potential |
Low |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Shelby Sewage Lagoon