Upper Big Nemaha 13-C Reservoir Report

Last Updated: December 5, 2025

Upper Big Nemaha 13-C is a local government-owned earth dam located in Lancaster, Nebraska, along the TR-MID BR Big Nemaha River.


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Summary

Constructed in 1994 by the USDA NRCS, this dam stands at a height of 30 feet with a hydraulic height of 28 feet and a structural height of 35 feet. With a storage capacity of 594 acre-feet and a drainage area of 1.7 square miles, the dam serves multiple purposes including flood risk reduction. The dam's condition was last assessed in June 2016 and was found to be in satisfactory condition with a low hazard potential.

Managed by the NE DNR, Upper Big Nemaha 13-C undergoes regular inspections every 5 years to ensure its structural integrity and functionality. Despite being classified as low risk, the dam has a maximum discharge capacity of 577 cubic feet per second and a normal storage capacity of 114 acre-feet. The dam's location in Firth, Nebraska, makes it a critical infrastructure for water resource management in the area. With a stone core and soil foundation, Upper Big Nemaha 13-C plays a crucial role in regulating water flow and mitigating potential flood risks.

As part of the Natural Resources Conservation Service's network of dams, Upper Big Nemaha 13-C contributes to the overall water management strategy in the region. With its earth construction and satisfactory condition, the dam provides valuable insights into sustainable water resource management practices. Climate and water resource enthusiasts can appreciate the importance of structures like Upper Big Nemaha 13-C in maintaining the ecological balance and ensuring water security in the face of changing climate patterns.

Year Completed

1994

Dam Length

795

Dam Height

30

River Or Stream

TR-MID BR BIG NEMAHA RIVER

Primary Dam Type

Earth

Surface Area

24

Hydraulic Height

28

Drainage Area

1.7

Nid Storage

594

Structural Height

35

Hazard Potential

Low

Foundations

Soil

Nid Height

35
       
Seasonal Comparison

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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.