Upper Glasston North Dam

SWEETGRASS CANAL OFFSTREAM· Sweet Grass, Montana· Built 1912· Earth· 20 ft tall
High Hazard Irrigation Private

Key Takeaway

Upper Glasston North Dam is classified as high hazard in Montana. It was completed in 1912 and is 114 years old. Its primary use is irrigation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 20 ft (taller than 44.5% in MT)
Dam Length600 ft
Dam TypeEarth
Max Storage1.8K acre-ft
Normal Storage924 acre-ft
Year Completed1912 (114 years old)
NID IDMT03267

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: July 10, 2021
State Regulated: Yes
Regulatory Agency: DNRC

Ownership

SWEETGRASS CANAL & RES CO

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Upper Glasston North Dam?

Upper Glasston North Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Upper Glasston North Dam?

Upper Glasston North Dam is owned by SWEETGRASS CANAL & RES CO (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Upper Glasston North Dam built?

Upper Glasston North Dam was completed in 1912, making it 114 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Upper Glasston North Dam?

Upper Glasston North Dam serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Upper Glasston North Dam?

Upper Glasston North Dam has a dam height of 20 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Upper Glasston North Dam last inspected?

Upper Glasston North Dam was last inspected on July 10, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.