Big Falls
Big Falls is a gravity dam located in Rusk County, Wisconsin, built in 1923. It carries a High hazard potential classification and has a fair condition assessment.
About Big Falls
The primary purpose of Big Falls 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 Northern States Power Co (public utility). It impounds the Flambeau near Ladysmith.
The dam stands 50 feet tall and stretches 2,196 feet across, creates a reservoir covering 369 acres, has a maximum storage capacity of 4,000 acre-feet, and collects water from a drainage area of 1,786 square miles. Completed in 1923, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 09/20/2022.
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 Wisconsin 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 | Wisconsin |
| County | Rusk |
| Nearest City | Ladysmith |
| River/Stream | Flambeau |
| Coordinates | 45.55550, -90.95920 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 50 ft |
| Dam Height | 50 ft |
| Dam Length | 2,196 ft |
| Year Completed | 1923 (103 years old) |
Storage & Hydraulics
| NID Storage | 4,000 acre-ft |
| Max Storage | 4,000 acre-ft |
| Normal Storage | 4,000 acre-ft |
| Surface Area | 369 acres |
| Drainage Area | 1,786 sq mi |
| Max Discharge | 91,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Northern States Power Co |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 09/20/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WI00793 |
| Federal ID | WI00793 |
| More Info | State Dam Safety Program |