Upper Little Nemaha 18 dam
Upper Little Nemaha 18
Upper Little Nemaha 18, located in Unadilla, Nebraska, is a vital flood risk reduction structure on Hooper Creek managed by the local government. Constructed in 1996, this earth dam stands at a height of 38 feet and has a storage capacity of 1735 acre-feet, serving a drainage area of 6.5 square miles. With a satisfactory condition assessment and low hazard potential, this structure plays a crucial role in mitigating flood risks and ensuring the safety of the surrounding community.
Managed by the Nebraska Department of Natural Resources, Upper Little Nemaha 18 is subject to state regulation, permitting, inspection, and enforcement. It is designed to withstand maximum discharges of up to 3798 cubic feet per second and has a spillway type and width not specified in the data. The dam's primary purpose is flood risk reduction, with a normal storage capacity of 200 acre-feet and a surface area of 35 acres. This structure reinforces the resilience of the local area against potential flooding events.
Congressional District 01's representative, Jeff Fortenberry, oversees Upper Little Nemaha 18 as part of the Kansas City District. The dam has a history of satisfactory inspections, last assessed in August 2016, with a regular inspection frequency of 5 years. With no documented emergency action plan or risk assessment, the structure's risk management measures and potential hazards are currently unspecified. As a crucial component of water resource management in Otoe County, Nebraska, Upper Little Nemaha 18 stands as a testament to proactive flood risk reduction efforts in the region.
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 Little Nemaha 18 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Stevens Creek Nr. Lincoln | 11 cfs | → |
| Salt Creek At Roca | 6 cfs | → |
| Salt Creek At 70th St. At Lincoln | 267 cfs | → |
| Salt Creek At Lincoln | 134 cfs | → |
| Salt Creek At Pioneers Blvd At Lincoln | 11 cfs | → |
| Salt Creek At Greenwood | 246 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Upper Little Nemaha 18.
Track Upper Little Nemaha 18 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 Little Nemaha 18
Where does the data for Upper Little Nemaha 18 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 Little Nemaha 18.