Upper Big Nemaha 20-B
Key Takeaway
Upper Big Nemaha 20-B is classified as low hazard in Nebraska. It was completed in 1973 and is 53 years old. Its primary use is flood risk reduction.
Physical Details
| Dam Height | 38 ft (taller than 87.6% in NE) |
| Dam Length | 1,127 ft |
| Dam Type | Earth |
| Max Storage | 430 acre-ft |
| Normal Storage | 91 acre-ft |
| Surface Area | 24 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 939 cfs |
| Year Completed | 1973 (53 years old) |
| NID ID | NE00644 |
Safety Information
No probable loss of human life and low economic/environmental losses expected.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
Nemaha Natural Resources District
Local Government
Nearby Dams
Upper Big Nemaha 20-A
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Low Hazard 40 ftUpper Big Nemaha 21-A
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Low Hazard 33 ftUpper Big Nemaha 20-C
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Low Hazard 35 ftUpper Big Nemaha G-16a
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Low Hazard 26 ftUpper Big Nemaha L-12
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Low Hazard 22 ftUpper Big Nemaha J-11
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Low Hazard 22 ftUpper Big Nemaha G-15
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Low Hazard 32 ftUpper Big Nemaha J-12a
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Low Hazard 26 ftFrequently Asked Questions
What is the hazard classification of Upper Big Nemaha 20-B?
Upper Big Nemaha 20-B is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Upper Big Nemaha 20-B?
Upper Big Nemaha 20-B is owned by Nemaha Natural Resources District (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Upper Big Nemaha 20-B built?
Upper Big Nemaha 20-B was completed in 1973, making it 53 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of Upper Big Nemaha 20-B?
Upper Big Nemaha 20-B serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Upper Big Nemaha 20-B?
Upper Big Nemaha 20-B has a dam height of 38 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Upper Big Nemaha 20-B last inspected?
Upper Big Nemaha 20-B was last inspected on June 16, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.