Gollaher Reservoir

WILLOW CREEK· Cascade, Montana· Built 1945· Earth· 38 ft tall
Significant Hazard Irrigation Private

Key Takeaway

Gollaher Reservoir is classified as significant hazard in Montana. It was completed in 1945 and is 81 years old. Its primary use is irrigation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 38 ft (taller than 94.3% in MT)
Dam Length1,130 ft
Dam TypeEarth
Max Storage827 acre-ft
Normal Storage613 acre-ft
Surface Area41 acres
Drainage Area10 sq mi
Max Discharge525 cfs
Year Completed1945 (81 years old)
Year Modified1950
NID IDMT00204

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

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

Emergency Action Plan: No
State Regulated: Yes
Regulatory Agency: DNRC

Ownership

GOLLAHER RANCH CO.

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Gollaher Reservoir?

Gollaher Reservoir is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Gollaher Reservoir?

Gollaher Reservoir is owned by GOLLAHER RANCH CO. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Gollaher Reservoir built?

Gollaher Reservoir was completed in 1945, making it 81 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 Gollaher Reservoir?

Gollaher Reservoir 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 Gollaher Reservoir?

Gollaher Reservoir has a dam height of 38 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.