Cap Rock #4

HARRIS CREEK· Custer, Montana· Built 1954· Earth· 17 ft tall

Key Takeaway

Cap Rock #4 is classified as low hazard in Montana. It was completed in 1954 and is 72 years old. Its primary use is fire protection.

Physical Details

Dam Height 17 ft (taller than 34.9% in MT)
Dam Length175 ft
Dam TypeEarth
Max Storage125 acre-ft
Normal Storage56 acre-ft
Year Completed1954 (72 years old)
NID IDMT01799

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

CAP ROCK RANCH INC

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cap Rock #4?

Cap Rock #4 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 Cap Rock #4?

Cap Rock #4 is owned by CAP ROCK RANCH INC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cap Rock #4 built?

Cap Rock #4 was completed in 1954, making it 72 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 Cap Rock #4?

Cap Rock #4 serves the following purposes: Fire Protection, Stock, Or Small Fish Pond. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Cap Rock #4?

Cap Rock #4 has a dam height of 17 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.