Twp Road 18 is an earth dam located in Lyon County, Minnesota, built in 2000. It carries a Low hazard potential classification.
Dam profile
NID height · 24 ft24 ft tall and 600 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Twp Road 18
The primary purpose of Twp Road 18 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-os near Tracy.
The dam stands 24 feet tall and stretches 600 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 88 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 2000, the structure is 26 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. The most recent inspection on record was 07/31/2024.
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Location
| State | Minnesota |
| County | Lyon |
| Nearest City | Tracy |
| River/Stream | Cottonwood River-os |
| Coordinates | 44.25331, -95.61720 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 24 ft |
| Dam Height | 23 ft |
| Dam Length | 600 ft |
| Year Completed | 2000 (26 years old) |
Storage & Hydraulics
| NID Storage | 88 acre-ft |
| Max Storage | 88 acre-ft |
| Normal Storage | 1 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 556 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | County of Lyon |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 07/31/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN01366 |
| Federal ID | MN01366 |
| More Info | State Dam Safety Program |