Bynum Reservoir Dam
Bynum Reservoir Dam is an earth dam located in Teton County, Montana, built in 1926. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Bynum Reservoir Dam
The primary purpose of Bynum Reservoir Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Teton Cooperative Reservoir Company (private). It impounds the Miller Creek near Bynum.
The dam stands 60 feet tall and stretches 3,700 feet across, creates a reservoir covering 3,200 acres, has a maximum storage capacity of 107,000 acre-feet, and collects water from a drainage area of 32 square miles. Completed in 1926, 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 04/24/2024.
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.
Location
| State | Montana |
| County | Teton |
| Nearest City | Bynum |
| River/Stream | Miller Creek |
| Coordinates | 47.96480, -112.41600 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 60 ft |
| Dam Height | 60 ft |
| Dam Length | 3,700 ft |
| Year Completed | 1926 (100 years old) |
Storage & Hydraulics
| NID Storage | 107,000 acre-ft |
| Max Storage | 107,000 acre-ft |
| Normal Storage | 87,000 acre-ft |
| Surface Area | 3,200 acres |
| Drainage Area | 32 sq mi |
| Max Discharge | 2,000 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | TETON COOPERATIVE RESERVOIR COMPANY |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/24/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT01356 |
| Federal ID | MT01356 |
| More Info | State Dam Safety Program |