Dd No 204, also known as Rock Creek Watershed Dam No 204, is a flood risk reduction structure located in Lyon County, Kansas. This earth dam has a height of 25 feet and a length of 775 feet, providing a storage capacity of 183.9 acre-feet and normal storage of 39.8 acre-feet. The dam is situated on Bluff Creek, within the Kansas City District, and is owned and operated by the local government in the city of Dunlap.

Managed by the USDA NRCS, Dd No 204 serves the primary purpose of flood risk reduction in the area, with a low hazard potential and a moderate risk assessment rating. While the dam has not been rated for its current condition, it has not undergone any recent modifications or inspections since April 2005. The spillway type for this structure is uncontrolled, with a width of 70 feet and a maximum discharge capacity of 1848 cubic feet per second.

Water resource and climate enthusiasts interested in the management and infrastructure of flood control systems will find Dd No 204 to be an intriguing case study. With its unique design features, location, and purpose, this dam provides valuable insight into the efforts to mitigate flood risks and protect communities in the region. As a critical piece of infrastructure in the Rock Creek watershed, Dd No 204 plays a vital role in safeguarding the area against potential flooding events, highlighting the importance of effective water resource management and climate resilience strategies.