Osseo
Osseo is a gravity dam located in Trempealeau County, Wisconsin, built in 1860. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Osseo
The primary purpose of Osseo is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City Of Osseo (local government). It impounds the South Fork Buffalo near Osseo.
The dam stands 14 feet tall and stretches 451 feet across, creates a reservoir covering 13 acres, has a maximum storage capacity of 100 acre-feet, and collects water from a drainage area of 38 square miles. Completed in 1860, the structure is one of the older dams in the region, with over a century and a half 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 05/29/2020.
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 | Trempealeau |
| Nearest City | Osseo |
| River/Stream | South Fork Buffalo |
| Coordinates | 44.57680, -91.22367 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 451 ft |
| Year Completed | 1860 (166 years old) |
Storage & Hydraulics
| NID Storage | 100 acre-ft |
| Max Storage | 100 acre-ft |
| Normal Storage | 45 acre-ft |
| Surface Area | 13 acres |
| Drainage Area | 38 sq mi |
| Max Discharge | 2,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City Of Osseo |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/29/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WI10621 |
| Federal ID | WI10621 |
| More Info | State Dam Safety Program |