Big Stone Lake
Big Stone Lake is an earth dam located in Big Stone County, Minnesota, built in 1937. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Big Stone Lake
The primary purpose of Big Stone Lake is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Mndnr;umrws (state). It impounds the Minnesota River near Ortonville.
The dam stands 15 feet tall and stretches 6,300 feet across, creates a reservoir covering 12,094 acres, has a maximum storage capacity of 205,000 acre-feet, and collects water from a drainage area of 1,182 square miles. Completed in 1937, the structure is well-established, with more than 75 years of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 07/20/2023.
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Location
| State | Minnesota |
| County | Big Stone |
| Nearest City | Ortonville |
| River/Stream | Minnesota River |
| Coordinates | 45.29695, -96.44879 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 6,300 ft |
| Year Completed | 1937 (89 years old) |
Storage & Hydraulics
| NID Storage | 205,000 acre-ft |
| Max Storage | 205,000 acre-ft |
| Normal Storage | 100,880 acre-ft |
| Surface Area | 12,094 acres |
| Drainage Area | 1,182 sq mi |
| Max Discharge | 5,600 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | MNDNR;UMRWS |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/20/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN00169 |
| Federal ID | MN00169 |
| More Info | State Dam Safety Program |