O S W, also known as Burlington, is a private irrigation dam located in Lysite, Wyoming, along the Badwater Creek. Completed in 1912, this earth dam stands at a height of 28 feet and has a normal storage capacity of 177 acre-feet. With a hazard potential rated as high and a poor condition assessment as of June 2017, O S W poses significant challenges in terms of maintenance and safety.

Despite being state-regulated and having state jurisdiction, O S W lacks federal oversight and funding. The dam features an uncontrolled spillway with a width of 125 feet and one uncontrolled outlet gate. Its purpose is solely for irrigation, serving the surrounding agricultural lands. However, with a drainage area of 2.1 square miles and a maximum discharge of 900 cfs, the dam plays a crucial role in managing water resources in the region.

Given its age and condition, O S W presents a moderate risk and requires regular inspections and maintenance to ensure its structural integrity. With its historical significance dating back over a century, this private irrigation dam remains a key component of water management in Fremont County, Wyoming.