Upper Big Nemaha G-12 is a local government-owned earth dam located in Gage County, Nebraska, along the TR-MID BR Big Nemaha River. Built in 1973 by USDA NRCS, this dam stands at a height of 21 feet and has a storage capacity of 69 acre-feet. Its primary purpose is flood risk reduction, with a normal storage capacity of 22 acre-feet and a maximum discharge of 545 cubic feet per second.

Managed and regulated by the Nebraska Department of Natural Resources, Upper Big Nemaha G-12 has a low hazard potential and is deemed to be in satisfactory condition as of the last inspection in May 2020. The dam spans 480 feet in length, with a hydraulic height of 20 feet and a structural height of 22 feet. Despite its modest size, this dam plays a crucial role in mitigating flood risks and protecting the surrounding area from potential water-related hazards.

Situated in a picturesque location near Sterling, Nebraska, Upper Big Nemaha G-12 serves as a vital infrastructure for water resource management in the region. With its stone core and soil foundation, this dam showcases the collaborative efforts between local government agencies and the USDA NRCS in safeguarding the community against the impacts of extreme weather events and ensuring the sustainable use of water resources in the area.