Located in Lancaster, Nebraska, the Upper Little Nemaha 21 dam is a crucial flood risk reduction structure along the Little Nemaha River.
Wind
Humidity
Constructed in 1998, this earth dam stands at a height of 51 feet and stretches 2400 feet in length, with a storage capacity of 2439 acre-feet. Managed by Olsson Associates and regulated by the Nebraska Department of Natural Resources, the dam is designed to handle a maximum discharge of 15225 cubic feet per second, serving as a vital protective barrier for the surrounding rural community of Bennet.
With a hazard potential rated as high, the Upper Little Nemaha 21 dam undergoes regular inspections to ensure its structural integrity. The condition assessment conducted in August 2020 deemed the dam to be in satisfactory condition, meeting safety guidelines. While an Emergency Action Plan (EAP) was last revised in June 2015, there is room for improvement in terms of updating emergency contacts, preparing inundation maps, and conducting a comprehensive risk assessment. As a significant asset for flood control in the region, continued monitoring and maintenance are essential to uphold the dam's effectiveness in safeguarding the area from potential water-related disasters.
Year Completed |
1998 |
Dam Length |
2400 |
Dam Height |
51 |
River Or Stream |
LITTLE NEMAHA RIVER |
Primary Dam Type |
Earth |
Surface Area |
40 |
Hydraulic Height |
51 |
Drainage Area |
5.5 |
Nid Storage |
2439 |
Structural Height |
59 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
59 |