Upper Big Nemaha G-23 Reservoir Report

Last Updated: December 6, 2025

Upper Big Nemaha G-23 is a local government-owned dam located in Gage County, Nebraska, specifically in the city of Sterling.


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Summary

Built in 1967 by the USDA NRCS, this earth dam stands at a height of 28 feet and stretches 600 feet in length. Its primary purpose is flood risk reduction, with a storage capacity of 57 acre-feet and a drainage area of 0.2 square miles along the TR-N FK Big Nemaha River.

Managed by the Nebraska Department of Natural Resources, Upper Big Nemaha G-23 is regulated, permitted, inspected, and enforced by the state to ensure its structural integrity and functionality. Despite being classified as a low-hazard potential dam with a fair condition assessment, it has a regular inspection frequency of every 5 years to monitor its performance. The dam's emergency action plan status and risk assessment details are currently unavailable, but it serves as a vital infrastructure for water resource management and climate resilience in the region.

Overall, Upper Big Nemaha G-23 plays a crucial role in managing flood risks and providing water storage in Gage County, Nebraska. With its strategic location and design features, this dam serves as a key asset for the local community and underscores the importance of effective dam management practices in safeguarding water resources and enhancing climate adaptability in the face of changing environmental conditions.

Year Completed

1967

Dam Length

600

Dam Height

28

River Or Stream

TR-N FK BIG NEMAHA RIVER

Primary Dam Type

Earth

Surface Area

5

Hydraulic Height

28

Drainage Area

0.2

Nid Storage

57

Structural Height

28

Hazard Potential

Low

Foundations

Soil

Nid Height

28
       
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.