Upper Big Nemaha G-33 Reservoir Report
Last Updated: December 5, 2025
Upper Big Nemaha G-33 is a local government-owned earth dam located in Gage County, Nebraska, along the Big Nemaha River.
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Summary
Built in 1983 by the USDA NRCS, this dam stands at a height of 28 feet and spans 990 feet in length, providing flood risk reduction and other purposes for the community. With a storage capacity of 152 acre-feet and a drainage area of 0.5 square miles, Upper Big Nemaha G-33 plays a critical role in managing water resources in the region.
Managed by the Nebraska Department of Natural Resources, Upper Big Nemaha G-33 has a low hazard potential and is deemed to be in satisfactory condition as of the last inspection in March 2020. Despite its age, the dam continues to effectively serve its purpose, with a normal storage capacity of 59 acre-feet and a maximum discharge rate of 159 cubic feet per second. With state-regulated permitting, inspection, and enforcement in place, this dam exemplifies responsible water resource management and climate resilience efforts in the area.
As part of the Omaha District, Upper Big Nemaha G-33 benefits from the expertise and oversight of the USDA NRCS, ensuring that the dam meets regulatory standards and remains structurally sound. With its stone core and soil foundation, this earth dam is a testament to the collaboration between local government and federal agencies in safeguarding communities from potential flooding events. As climate change impacts water resources, the importance of well-maintained structures like Upper Big Nemaha G-33 cannot be understated in ensuring the safety and sustainability of the region's water supply.
Year Completed |
1983 |
Dam Length |
990 |
Dam Height |
24 |
River Or Stream |
TR-BIG NEMAHA RIVER |
Primary Dam Type |
Earth |
Surface Area |
12 |
Hydraulic Height |
23 |
Drainage Area |
0.5 |
Nid Storage |
152 |
Structural Height |
28 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
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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