Middle Big Nemaha 46 is an earth dam located in Johnson County, Nebraska, built in 1995. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 59 ft59 ft tall and 1,122 ft long, taller than 95% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Middle Big Nemaha 46
The primary purpose of Middle Big Nemaha 46 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 Nemaha Natural Resources District (local government). It impounds the Lost Br Tr-yankee Creek near Tecumseh.
The dam stands 59 feet tall and stretches 1,122 feet across, creates a reservoir covering 52 acres, has a maximum storage capacity of 3,152 acre-feet, and collects water from a drainage area of 9 square miles. Completed in 1995, the structure is 31 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 06/09/2021.
At 59 feet, this dam is taller than 95% of all dams in the United States.
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Location
| State | Nebraska |
| County | Johnson |
| Nearest City | Tecumseh |
| River/Stream | Lost Br Tr-yankee Creek |
| Coordinates | 40.32620, -96.36467 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 59 ft |
| Dam Height | 48 ft |
| Dam Length | 1,122 ft |
| Year Completed | 1995 (31 years old) |
Storage & Hydraulics
| NID Storage | 3,152 acre-ft |
| Max Storage | 3,152 acre-ft |
| Normal Storage | 292 acre-ft |
| Surface Area | 52 acres |
| Drainage Area | 9 sq mi |
| Max Discharge | 5,832 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Nemaha Natural Resources District |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 06/09/2021 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NE02470 |
| Federal ID | NE02470 |
| More Info | State Dam Safety Program |