Lake John
Lake John is an earth dam located in Yellow Medicine County, Minnesota, built in 1981. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Lake John
The primary purpose of Lake John is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Wd Of Yellow Medicine River (local government). It impounds the Mud Creek-tr near Porter.
The dam stands 43 feet tall and stretches 1,000 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 557 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1981, the structure is 45 years old.
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 05/28/2024.
At 43 feet, this dam is taller than 89% of dams nationwide.
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Location
| State | Minnesota |
| County | Yellow Medicine |
| Nearest City | Porter |
| River/Stream | Mud Creek-tr |
| Coordinates | 44.64242, -96.22546 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 43 ft |
| Dam Height | 43 ft |
| Dam Length | 1,000 ft |
| Year Completed | 1981 (45 years old) |
Storage & Hydraulics
| NID Storage | 557 acre-ft |
| Max Storage | 557 acre-ft |
| Normal Storage | 155 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 3,200 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | WD of Yellow Medicine River |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/28/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN00981 |
| Federal ID | MN00981 |
| More Info | State Dam Safety Program |