Monroe 4
Monroe 4 is a dam located in Lyon County, Minnesota, built in 1989. It carries a Low hazard potential classification and has a fair condition assessment.
About Monroe 4
The primary purpose of Monroe 4 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-tr.
The dam stands 15 feet tall and stretches 380 feet across, has a maximum storage capacity of 121 acre-feet, and collects water from a drainage area of 8 square miles. Completed in 1989, the structure is 37 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 04/05/2019.
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Location
| State | Minnesota |
| County | Lyon |
| Nearest City | None |
| River/Stream | Cottonwood River-tr |
| Coordinates | 44.28298, -95.65644 |
Physical Characteristics
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 380 ft |
| Year Completed | 1989 (37 years old) |
Storage & Hydraulics
| NID Storage | 121 acre-ft |
| Max Storage | 121 acre-ft |
| Drainage Area | 8 sq mi |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | County of Lyon |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 04/05/2019 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN01748 |
| Federal ID | MN01748 |
| More Info | State Dam Safety Program |