Upper Big Nemaha 3-A dam
Upper Big Nemaha 3-A
Upper Big Nemaha 3-A is a vital earth dam located in Johnson, Nebraska, designed by the USDA NRCS in 1985 for flood risk reduction along the TR-Mid Br Big Nemaha River. This structure, owned by the local government, stands at a height of 43.5 feet with a storage capacity of 1412.7 acre-feet and a drainage area of 3.4 square miles. With a low hazard potential and satisfactory condition assessment, the dam plays a crucial role in mitigating potential flooding events in the area.
Operated and regulated by the Nebraska Department of Natural Resources, Upper Big Nemaha 3-A undergoes regular inspections, with the last assessment conducted in May 2017, affirming its structural integrity. With a primary purpose of flood risk reduction, this dam serves as a critical component in the local water resource management system, safeguarding the surrounding community from potential inundation. The dam's design, featuring stone core and soil foundation, ensures its effectiveness in controlling water flow and protecting downstream areas from excess discharge.
With a comprehensive emergency action plan and adherence to regulatory guidelines, Upper Big Nemaha 3-A exhibits a commitment to proactive risk management and safety measures. As climate change continues to impact precipitation patterns and increase the frequency of extreme weather events, structures like this earth dam play a vital role in ensuring the resilience and sustainability of water resources in the region. As water resource and climate enthusiasts, understanding the significance of infrastructure like Upper Big Nemaha 3-A is crucial in addressing the challenges posed by a changing climate and safeguarding communities against the impacts of flooding.
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.
- 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.
- 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.
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, environmental 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.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Upper Big Nemaha 3-A -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Salt Creek At Roca | 6 cfs | → |
| Turkey Creek Near De Witt | 195 cfs | → |
| Salt Creek At Pioneers Blvd At Lincoln | 11 cfs | → |
| Haines Branch At Sw 56th St. At Lincoln | 2 cfs | → |
| Stevens Creek Nr. Lincoln | 11 cfs | → |
| Big Blue River Near Crete | 226 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Upper Big Nemaha 3-A.
Track Upper Big Nemaha 3-A in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Upper Big Nemaha 3-A
Where does the data for Upper Big Nemaha 3-A come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Upper Big Nemaha 3-A.