Upper Big Nemaha G-35 Reservoir Report

Last Updated: December 5, 2025

Upper Big Nemaha G-35 is a vital water resource structure located in Gage County, Nebraska, designed by the USDA NRCS and completed in 1973.


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Summary

This earth dam stands at a height of 21 feet and boasts a storage capacity of 197 acre-feet, serving primarily for flood risk reduction purposes. With a satisfactory condition assessment and low hazard potential, this dam plays a crucial role in managing water flow in the TR-SHAW CREEK watershed.

Managed by the local government and regulated by the Nebraska Department of Natural Resources, Upper Big Nemaha G-35 is subject to state permitting, inspection, and enforcement. With a drainage area of 0.9 square miles and a maximum discharge capacity of 590 cubic feet per second, this structure contributes to the overall water management efforts in the region. Its location in Adams, Nebraska, highlights its importance in safeguarding the surrounding communities from potential flooding events.

Despite its modest size and capacity, Upper Big Nemaha G-35 remains a key component in the water infrastructure of the area, ensuring the protection of residents and property from the impacts of extreme weather events. With its stone core and soil foundation, this dam continues to fulfill its purpose of flood risk reduction and water storage, showcasing the collaborative efforts between local government and federal agencies in managing water resources effectively.

Year Completed

1973

Dam Length

675

Dam Height

21

River Or Stream

TR-SHAW CREEK

Primary Dam Type

Earth

Surface Area

11

Hydraulic Height

21

Drainage Area

0.9

Nid Storage

197

Structural Height

22

Hazard Potential

Low

Foundations

Soil

Nid Height

22
       
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.