Upper Big Nemaha J-45 is a vital earth dam located in Johnson, Nebraska, designed by the USDA NRCS to serve the primary purpose of flood risk reduction. Constructed in 1980, this dam stands at a height of 26 feet and has a normal storage capacity of 26 acre-feet. The dam overlooks the TR-N FK Big Nemaha River and covers a surface area of 4 acres, providing protection to a drainage area of 0.4 square miles.

Managed by the local government, Upper Big Nemaha J-45 is regulated by the Nebraska Department of Natural Resources and undergoes regular inspections to ensure its structural integrity and functionality. With a low hazard potential and satisfactory condition assessment, this dam plays a crucial role in mitigating flood risks and protecting the surrounding community. Despite its modest size, Upper Big Nemaha J-45 serves as a crucial water resource infrastructure in the region.

Enthusiasts of water resources and climate will appreciate the strategic placement and design of Upper Big Nemaha J-45, as it showcases how local governments and agencies work together to address flood risks and protect communities. With its earth structure and stone core, this dam exemplifies efficient water management practices and highlights the importance of regular inspections and maintenance to ensure its continued effectiveness in safeguarding the area from potential floods.