Upper Big Nemaha 14-A Reservoir Report

Last Updated: December 5, 2025

Upper Big Nemaha 14-A, located in Lancaster, Nebraska, is a local government-owned earth dam designed by USDA NRCS to primarily manage flood risk along the TR-MID BR Big Nemaha River.


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Summary

Completed in 1983, this dam stands at a height of 21 feet and has a hydraulic height of 20 feet, providing a storage capacity of 210 acre-feet. With a satisfactory condition assessment and low hazard potential, this structure plays a crucial role in flood risk reduction in the region.

Managed by the Nebraska Department of Natural Resources, Upper Big Nemaha 14-A is subject to state regulation, inspection, and enforcement to ensure its structural integrity and operational effectiveness. The dam's drainage area spans 0.5 square miles, with a maximum discharge capacity of 665 cubic feet per second. With a history of regular inspections and a last assessment in September 2016, this dam has shown a reliable performance in safeguarding the surrounding area from potential flooding events.

Despite its modest size and localized impact, Upper Big Nemaha 14-A serves as a vital component of the flood management infrastructure in the region. With its stone core and soil foundation, this earth dam reflects a successful collaboration between federal agencies, local government, and regulatory bodies to enhance resilience to climate-related risks and protect the community from potential water-related disasters.

Year Completed

1983

Dam Length

673

Dam Height

21

River Or Stream

TR-MID BR BIG NEMAHA RIVER

Primary Dam Type

Earth

Surface Area

7

Hydraulic Height

20

Drainage Area

0.5

Nid Storage

210

Structural Height

24

Hazard Potential

Low

Foundations

Soil

Nid Height

24
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.