Mad Dam

TR-ARROW CREEK· Judith Basin, Montana· Built 1955· Earth· 26 ft tall
Low Hazard Irrigation Private

Key Takeaway

Mad Dam is classified as low hazard in Montana. It was completed in 1955 and is 71 years old. Its primary use is irrigation.

Physical Details

Dam Height 26 ft (taller than 77.8% in MT)
Dam Length25 ft
Dam TypeEarth
Max Storage60 acre-ft
Normal Storage54 acre-ft
Max Discharge300 cfs
Year Completed1955 (71 years old)
NID IDMT01269

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: Yes
Regulatory Agency: DNRC

Ownership

PHILIP & PEGGY JOHNSON

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mad Dam?

Mad Dam 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 Mad Dam?

Mad Dam is owned by PHILIP & PEGGY JOHNSON (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Mad Dam built?

Mad Dam was completed in 1955, making it 71 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 Mad Dam?

Mad 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 Mad Dam?

Mad Dam has a dam height of 26 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.