Upper Big Nemaha 12-B is a local government-owned dam located in Lancaster, Nebraska, designed by the USDA NRCS and regulated by the NE DNR. Completed in 1994, this earth dam stands at a height of 29 feet and serves the primary purpose of flood risk reduction along the TR-Mid Br Big Nemaha River. With a storage capacity of 1231 acre-feet and a drainage area of 3.4 square miles, the dam boasts a low hazard potential and satisfactory condition assessment.

This dam plays a crucial role in managing water resources in the region, providing protection against potential flooding events. With a normal storage capacity of 251 acre-feet and a maximum discharge rate of 632 cubic feet per second, Upper Big Nemaha 12-B helps mitigate the risk of flooding and ensures the safety of nearby communities. Additionally, its location in the Omaha District and close proximity to the city of Firth highlights its strategic importance in water resource management for the area.

The dam's design, construction, and operation adhere to state regulations and undergo regular inspections to maintain its functionality. The last inspection in September 2016 confirmed its satisfactory condition, with an inspection frequency of 5 years. Despite its low hazard potential, Upper Big Nemaha 12-B remains a critical infrastructure for flood risk reduction and water resource management in the region, showcasing the collaborative efforts between federal, state, and local agencies to safeguard against potential water-related disasters.