Pool No. 21 is an earth dam located in Marshall County, Minnesota, built in 1971. It carries a Low hazard potential classification.
Dam profile
NID height · 8 ft8 ft tall and 1,300 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 Pool No. 21
The primary purpose of Pool No. 21 is fish and wildlife pond. The dam creates habitat for fish and wildlife, supporting local ecosystems and potentially serving conservation goals. The dam is owned by USFWS (federal). It impounds the MUD River near Thief River Falls.
The dam stands 8 feet tall and stretches 1,300 feet across, and has a maximum storage capacity of 5,370 acre-feet. Completed in 1971, the structure is well into its service life at over 50 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.
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Location
| State | Minnesota |
| County | Marshall |
| Nearest City | Thief River Falls |
| River/Stream | MUD River |
| Coordinates | 48.36986, -95.88831 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 8 ft |
| Dam Height | 8 ft |
| Dam Length | 1,300 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 5,370 acre-ft |
| Max Storage | 5,370 acre-ft |
| Normal Storage | 2,100 acre-ft |
| Max Discharge | 1,400 cfs |
Ownership & Safety
| Purpose | Fish and Wildlife Pond |
| Owner | USFWS |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN00625 |
| Federal ID | MN00625 |
| More Info | State Dam Safety Program |