T L Johnson #1 Reservoir Report
Last Updated: December 7, 2025
T L Johnson #1 is a privately owned earth dam located in Forsyth, Montana, along the TR-Big Porcupine Creek.
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Summary
Built in 1957, this dam stands at a height of 22 feet and serves multiple purposes, including fire protection, stock, and a small fish pond. With a storage capacity of 152 acre-feet, the dam is regulated by the DNRC and is inspected, permitted, and enforced by the state of Montana.
Despite its age, T L Johnson #1 has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. While details on the dam's surface area, drainage area, and spillway type are not provided, the dam's primary purpose and design suggest a focus on local water resource management and conservation efforts. With the dam being located in a remote area, it serves as an essential water source for firefighting and livestock operations in the region.
As a significant structure in the area, T L Johnson #1 underscores the importance of maintaining and monitoring earth dams for sustainable water resource management. Its role in providing essential services for fire protection and livestock highlights the critical intersection between water infrastructure and climate resilience in rural communities. With its state-regulated status and low hazard potential, T L Johnson #1 serves as a model for responsible dam ownership and management practices in Montana.
Year Completed |
1957 |
Dam Length |
275 |
Dam Height |
22 |
River Or Stream |
TR-BIG PORCUPINE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
22 |
Nid Storage |
152 |
Hazard Potential |
Low |
Nid Height |
22 |
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.
T L Johnson #1