Frd No 81, also known as Upper Black Vermillion WS Dam 81, is a flood risk reduction structure located in Vliets, Kansas. Constructed in 1971 by the USDA NRCS, this earth dam stands at a height of 25 feet and spans 710 feet in length. With a primary purpose of flood risk reduction, Frd No 81 plays a key role in protecting the surrounding area from potential water-related hazards.

Situated on the North Fork Black Vermillion River, Frd No 81 has a storage capacity of 52 acre-feet and covers a surface area of 3.89 acres. The dam's spillway is uncontrolled with a width of 40 feet, and it is classified as having a low hazard potential. Despite not having a current condition assessment, Frd No 81 is deemed to have a moderate risk level of 3, highlighting its importance in managing water resources and climate-related risks in the region.

Maintained by the Natural Resources Conservation Service, Frd No 81 is a critical piece of infrastructure that contributes to the overall water management efforts in Marshall County, Kansas. As climate change continues to impact the frequency and intensity of weather events, structures like Frd No 81 play a crucial role in mitigating flood risks and protecting communities and ecosystems downstream.