Saint Marys Diversion

SAINT MARY RIVER· Glacier, Montana· Built 1920· Concrete· 29 ft tall
Low Hazard Irrigation Federal Government

Key Takeaway

Saint Marys Diversion is classified as low hazard in Montana. It was completed in 1920 and is 106 years old. Its primary use is irrigation.

Physical Details

Dam Height 29 ft (taller than 82.2% in MT)
Dam Length198 ft
Dam TypeConcrete
Max Storage100 acre-ft
Normal Storage100 acre-ft
Year Completed1920 (106 years old)
NID IDMT04010

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

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

Emergency Action Plan: No
State Regulated: No

Ownership

RECLAMATION

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Saint Marys Diversion?

Saint Marys Diversion is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Saint Marys Diversion?

Saint Marys Diversion is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Saint Marys Diversion built?

Saint Marys Diversion was completed in 1920, making it 106 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 Saint Marys Diversion?

Saint Marys Diversion 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 Saint Marys Diversion?

Saint Marys Diversion has a dam height of 29 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.

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.