Broadwater Dam

Broadwater Dam is a gravity dam located in Broadwater County, Montana, built in 1940. It carries a High hazard potential classification and has a satisfactory condition assessment.

About Broadwater Dam

The primary purpose of Broadwater Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Montana Dept Of Natural Resources & Conservation (state). It impounds the Missouri River near Toston, Mt.

The dam stands 50 feet tall and stretches 705 feet across, creates a reservoir covering 327 acres, has a maximum storage capacity of 6,460 acre-feet, and collects water from a drainage area of 14,660 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.

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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 03/25/2022.

At 50 feet, this dam is taller than 93% of dams nationwide.

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 HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateMontana
CountyBroadwater
Nearest CityToston, Mt
River/StreamMissouri River
Coordinates46.12000, -111.40830

Physical Characteristics

Dam TypeGravity
NID Height50 ft
Dam Height24 ft
Dam Length705 ft
Year Completed1940 (86 years old)

Storage & Hydraulics

NID Storage6,460 acre-ft
Max Storage6,460 acre-ft
Normal Storage4,100 acre-ft
Surface Area327 acres
Drainage Area14,660 sq mi
Max Discharge68,900 cfs
Spillway TypeControlled

Ownership & Safety

PurposeHydroelectric
OwnerMontana Dept of Natural Resources & Conservation
Owner TypeState
Hazard ClassificationHigh
Condition AssessmentSatisfactory
Last Inspection03/25/2022
Emergency Action PlanYes

Identifiers

NID IDMT00016
Federal IDMT00016
More InfoState Dam Safety Program

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