Langstaff #1 Reservoir Report

Last Updated: December 5, 2025

Langstaff #1 is a private earth dam located in Carbon County, Montana, specifically in the city of Fromberg.


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Summary

Built in 1945, this dam serves multiple purposes including fire protection, stock maintenance, and as a small fish pond. With a height of 25 feet and a length of 1320 feet, Langstaff #1 has a storage capacity of 535 acre-feet.

Managed by the Montana Department of Natural Resources and Conservation (DNRC), Langstaff #1 is classified as low hazard potential and its condition assessment is currently listed as "Not Rated." While the dam has not been inspected recently, it is reported to be in a good condition. The dam has state jurisdiction, permitting, inspection, and enforcement, ensuring its compliance with regulatory standards.

Located on the TR-Sand Creek river/stream, Langstaff #1 plays a crucial role in water resource management in the area. Its strategic location and multi-purpose design make it a valuable asset for fire protection, agricultural activities, and environmental conservation. For water resource and climate enthusiasts, Langstaff #1 serves as a fascinating example of sustainable water infrastructure in the state of Montana.

Year Completed

1945

Dam Length

1320

Dam Height

25

River Or Stream

TR-SAND CREEK

Primary Dam Type

Earth

Hydraulic Height

25

Nid Storage

535

Hazard Potential

Low

Nid Height

25
       
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.