Upper Glasston West Dam Reservoir Report

Last Updated: December 5, 2025

Upper Glasston West Dam, also known as Lake Adam West Dam, is a privately owned structure located in Sweet Grass, Montana, near the city of Greycliff.


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Summary

Completed in 1912, this earth dam stands at a height of 22 feet and serves primarily for irrigation purposes along the Sweetgrass Canal. With a storage capacity of 6236 acre-feet and a surface area of 407 acres, the dam plays a crucial role in supporting agricultural activities in the region.

Despite its long history, Upper Glasston West Dam has been classified as having a high hazard potential with a poor condition assessment. The last inspection in July 2021 revealed the need for improvements to ensure the safety and integrity of the structure. As a state-regulated facility under the jurisdiction of the Montana Department of Natural Resources and Conservation (DNRC), the dam undergoes regular inspections and enforcement measures to address any concerns.

As water resource and climate enthusiasts, understanding the significance of Upper Glasston West Dam in sustaining irrigation activities and managing water resources in the region is essential. With its historical importance and critical role in agriculture, efforts to maintain and improve the dam's safety and functionality are paramount to ensure the continued support of water supply for the local community and surrounding areas.

Year Completed

1912

Dam Length

300

Dam Height

22

River Or Stream

SWEETGRASS CANAL

Primary Dam Type

Earth

Surface Area

407

Hydraulic Height

16

Nid Storage

6236

Hazard Potential

High

Nid Height

22
       
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.