Madison Dam
Madison Dam is a timber crib dam located in Madison County, Montana, built in 1907. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Madison Dam
The primary purpose of Madison 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 Northwestern Energy (private). It impounds the Madison River near Three Forks, Mt.
The dam stands 39 feet tall and stretches 257 feet across, creates a reservoir covering 3,900 acres, has a maximum storage capacity of 42,053 acre-feet, and collects water from a drainage area of 2,181 square miles. Completed in 1907, 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 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 08/25/2021.
At 39 feet, this dam is taller than 86% 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.
Location
| State | Montana |
| County | Madison |
| Nearest City | Three Forks, Mt |
| River/Stream | Madison River |
| Coordinates | 45.47000, -111.63840 |
Physical Characteristics
| Dam Type | Timber Crib |
| NID Height | 39 ft |
| Dam Height | 39 ft |
| Dam Length | 257 ft |
| Year Completed | 1907 (119 years old) |
Storage & Hydraulics
| NID Storage | 42,053 acre-ft |
| Max Storage | 42,053 acre-ft |
| Normal Storage | 41,917 acre-ft |
| Surface Area | 3,900 acres |
| Drainage Area | 2,181 sq mi |
| Max Discharge | 7,700 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | NorthWestern Energy |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/25/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00561 |
| Federal ID | MT00561 |
| More Info | State Dam Safety Program |