Middle Big Nemaha 9 Reservoir Report
Nearby: Murphy Dam Schwisow Dam
Last Updated: December 6, 2025
Middle Big Nemaha 9, located in Crab Orchard, Nebraska, is a local government-owned earth dam designed by USDA NRCS and completed in 1995 for the primary purpose of flood risk reduction along the TR-Yankee Creek.
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Summary
With a height of 39 feet and a length of 785 feet, this dam provides a maximum storage capacity of 1096 acre-feet and covers a surface area of 27 acres. Despite its low hazard potential and satisfactory condition assessment, it is regulated and inspected by the Nebraska Department of Natural Resources to ensure its functionality and safety.
Managed by the Natural Resources Conservation Service, Middle Big Nemaha 9 serves as a critical infrastructure in the region's flood risk mitigation efforts, with a drainage area of 3.8 square miles and a maximum discharge capacity of 1813 cubic feet per second. The dam's stone core and soil foundation contribute to its structural integrity, while its hydraulic height of 38 feet and structural height of 44 feet further bolster its flood control capabilities. Although last inspected in 2016, with a scheduled inspection frequency of 5 years, the dam remains an essential component in protecting the surrounding community from potential flood events.
As part of the Omaha District's water resource management strategy, Middle Big Nemaha 9 plays a vital role in safeguarding Johnson County, Nebraska, from the devastating impacts of flooding. With its well-maintained condition, the dam continues to fulfill its purpose effectively, storing excess water during peak flow periods and mitigating flood risks for the local residents and infrastructure. As water resource and climate enthusiasts, understanding the significance of structures like Middle Big Nemaha 9 is crucial in promoting sustainable water management practices and resilience against changing climatic conditions.
Year Completed |
1995 |
Dam Length |
785 |
Dam Height |
39 |
River Or Stream |
TR-YANKEE CREEK |
Primary Dam Type |
Earth |
Surface Area |
27 |
Hydraulic Height |
38 |
Drainage Area |
3.8 |
Nid Storage |
1096 |
Structural Height |
44 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
44 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Turkey Creek Near De Witt
|
10cfs |
Little Blue River Near Fairbury
|
230cfs |
Big Blue River Near Crete
|
95cfs |
West Fork Big Blue River Nr Dorchester
|
39cfs |
Little Blue R At Hollenberg
|
70cfs |
Salt Creek At Roca
|
5cfs |
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.
Swan Creek 35
Swanton