Frd No W-4, also known as Fall River Watershed Dam W 4, is a vital earth dam located in Eureka, Kansas, owned by the local government and regulated by the Kansas Department of Agriculture. Built in 1970 by the USDA NRCS, this dam serves the primary purpose of flood risk reduction along the Cat Creek, with a significant hazard potential but a satisfactory condition assessment. With a height of 51.4 feet and a length of 2200 feet, Frd No W-4 has a storage capacity of 3220 acre-feet and a maximum discharge of 2450 cubic feet per second.

The dam's structure includes a buttress core type and an uncontrolled spillway type, with no outlet gates or associated structures. Despite its moderate risk assessment level, Frd No W-4 has not undergone any modifications in recent years and is inspected every 5 years to ensure its safety and functionality. Although the dam does not have an Emergency Action Plan in place or inundation maps prepared, it meets regulatory guidelines and is equipped with emergency contacts for any potential incidents. Overall, Frd No W-4 stands as a crucial asset in managing flood risks and protecting the surrounding community in Butler County, Kansas.