The Thrall Unit Flood Project in Eureka, Kansas, is a privately owned structure regulated by the Kansas Department of Agriculture. Built in 1950 by Sinclair Oil and Gas Co, this buttress dam on Swing Creek stands at 30 feet tall and stretches 990 feet in length, with a storage capacity of 230 acre-feet. Despite its low hazard potential, the dam has not been rated for its condition since its last inspection in 1950.

The project serves a primary purpose classified as "Other" and is designed to provide flood protection and water resource management in the region. Located in Greenwood County, Kansas, the dam's construction and operation fall under the jurisdiction of the state regulatory agency. With a maximum discharge of 1800 cubic feet per second, the Thrall Unit Flood Project plays a crucial role in mitigating flood risks and ensuring water security for the surrounding area.

As water resource and climate enthusiasts, the Thrall Unit Flood Project offers a fascinating case study in private dam ownership and management. With its historical significance dating back to the mid-20th century, this structure on Swing Creek continues to play a vital role in safeguarding the local community against potential flooding events. Its unique design and operational features make it a noteworthy example of sustainable water infrastructure in the state of Kansas.