Gibson Dam
Gibson Dam is a concrete dam located in Teton County, Montana, built in 1929. It carries a High hazard potential classification.
About Gibson Dam
The primary purpose of Gibson Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Bureau Of Reclamation (federal). It impounds the North Fork Sun River near Simms.
The dam stands 199 feet tall and stretches 960 feet across, creates a reservoir covering 1,420 acres, has a maximum storage capacity of 121,981 acre-feet, and collects water from a drainage area of 575 square miles. Completed in 1929, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/02/2021.
At 199 feet, this dam is taller than 99% 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 | Simms |
| River/Stream | North Fork Sun River |
| Coordinates | 47.60140, -112.76160 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 199 ft |
| Dam Height | 199 ft |
| Dam Length | 960 ft |
| Year Completed | 1929 (97 years old) |
Storage & Hydraulics
| NID Storage | 121,981 acre-ft |
| Max Storage | 121,981 acre-ft |
| Normal Storage | 99,059 acre-ft |
| Surface Area | 1,420 acres |
| Drainage Area | 575 sq mi |
| Max Discharge | 41,760 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 09/02/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00571 |
| Federal ID | MT00571 |
| More Info | State Dam Safety Program |