Rock Lake 15
Rock Lake 15 is a rockfill dam located in Lyon County, Minnesota, built in 1988. It carries a Low hazard potential classification and has a fair condition assessment.
About Rock Lake 15
The primary purpose of Rock Lake 15 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 County Of Lyon (local government). It impounds the Cottonwood River near Lamberton.
The dam stands 13 feet tall and stretches 800 feet across, has a maximum storage capacity of 500 acre-feet, and collects water from a drainage area of 26 square miles. Completed in 1988, the structure is 38 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 04/04/2019.
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Location
| State | Minnesota |
| County | Lyon |
| Nearest City | Lamberton |
| River/Stream | Cottonwood River |
| Coordinates | 44.25429, -95.87698 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 800 ft |
| Year Completed | 1988 (38 years old) |
Storage & Hydraulics
| NID Storage | 500 acre-ft |
| Max Storage | 500 acre-ft |
| Drainage Area | 26 sq mi |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | County of Lyon |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 04/04/2019 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN01784 |
| Federal ID | MN01784 |
| More Info | State Dam Safety Program |