Delmoe Lake Dam

Delmoe Lake Dam is an earth dam located in Jefferson County, Montana, built in 1914. It carries a High hazard potential classification and has a poor condition assessment.

About Delmoe Lake Dam

The primary purpose of Delmoe Lake Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Pipestone Water Users (private). It impounds the Big Pipestone Creek near Whitehall.

The dam stands 60 feet tall and stretches 290 feet across, creates a reservoir covering 310 acres, has a maximum storage capacity of 9,900 acre-feet, and collects water from a drainage area of 22 square miles. Completed in 1914, the structure is over a century old.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/16/2023.

At 60 feet, this dam is taller than 95% of all dams in the United States.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Montana dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardPoor ConditionEmergency Action Plan: Yes

Location

StateMontana
CountyJefferson
Nearest CityWhitehall
River/StreamBig Pipestone Creek
Coordinates45.98484, -112.34159

Physical Characteristics

Dam TypeEarth
NID Height60 ft
Dam Height60 ft
Dam Length290 ft
Year Completed1914 (112 years old)

Storage & Hydraulics

NID Storage9,900 acre-ft
Max Storage9,900 acre-ft
Normal Storage6,585 acre-ft
Surface Area310 acres
Drainage Area22 sq mi
Max Discharge1,900 cfs

Ownership & Safety

PurposeIrrigation
OwnerPIPESTONE WATER USERS
Owner TypePrivate
Hazard ClassificationHigh
Condition AssessmentPoor
Last Inspection10/16/2023
Emergency Action PlanYes

Identifiers

NID IDMT00117
Federal IDMT00117
More InfoState Dam Safety Program

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