Upper Big Nemaha L-4 is a locally owned dam in Lancaster, Nebraska, designed by USDA NRCS and regulated by the Nebraska Department of Natural Resources. Completed in 1971 for flood risk reduction, this earth dam stands at 26 feet high and spans 700 feet in length, with a storage capacity of 371 acre-feet. Situated on the TR-MID BR Big Nemaha River, this dam plays a crucial role in managing water resources in the region and has a significant hazard potential.

With a satisfactory condition assessment as of May 2018, Upper Big Nemaha L-4 is inspected every three years to ensure its structural integrity and functionality. While no emergency action plan has been reported, the dam's proximity to the surrounding community in Firth highlights the importance of effective risk management measures. Notably, the dam is not owned or funded by any federal agency, emphasizing the role of local government in maintaining and operating this vital infrastructure.

Enthusiasts of water resources and climate will find Upper Big Nemaha L-4 to be a key component of flood risk reduction in the area, with its earth design and stone core standing as a testament to effective water management practices. As climate change continues to impact weather patterns, the maintenance and oversight of dams like Upper Big Nemaha L-4 will be crucial in mitigating the potential for flooding and protecting local communities.