Upper Big Nemaha G-13 Reservoir Report
Last Updated: December 6, 2025
Upper Big Nemaha G-13 is a local government-owned dam located in Adams, Nebraska, along the TR-N FK Big Nemaha River.
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Summary
Built in 1967 by the USDA NRCS, this earth dam stands at a height of 30 feet and has a maximum storage capacity of 69 acre-feet. Its primary purpose is flood risk reduction, and it also serves other purposes. The dam has a low hazard potential and is in satisfactory condition, as assessed in June 2020.
Managed by the Nebraska Department of Natural Resources, Upper Big Nemaha G-13 is regulated, permitted, inspected, and enforced by the state. The dam's drainage area is 0.5 square miles, with a maximum discharge capacity of 487 cubic feet per second. Although the dam does not have a spillway or outlet gates, it has a hydraulic height of 25 feet and a structural height of 30 feet. As a crucial infrastructure for flood control in the region, the dam plays a vital role in protecting the surrounding areas from potential water-related risks.
With its strategic location and effective design, Upper Big Nemaha G-13 contributes significantly to the overall water resource management and climate resilience efforts in Gage County, Nebraska. As part of the local government's flood risk reduction strategy, this dam provides essential protection to the community and helps mitigate potential hazards during extreme weather events. With ongoing state oversight and maintenance, Upper Big Nemaha G-13 continues to serve its purpose effectively, ensuring the safety and well-being of residents and the environment in the region.
Year Completed |
1967 |
Dam Length |
450 |
Dam Height |
30 |
River Or Stream |
TR-N FK BIG NEMAHA RIVER |
Primary Dam Type |
Earth |
Surface Area |
1 |
Hydraulic Height |
25 |
Drainage Area |
0.5 |
Nid Storage |
69 |
Structural Height |
30 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
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