Fox Lake Dam, also known as El Dorado Dam, is a privately owned structure located in Cassoday, Kansas. Completed in 1928, this earth dam stands 33 feet tall and stretches 2410 feet in length along the Walnut River-TR. With a primary purpose of recreation, the dam provides a storage capacity of 3630 acre-feet and is regulated by the Kansas Department of Agriculture.

The dam's hazard potential is classified as high, but its condition assessment remains satisfactory as of the last inspection in August 2020. While the dam has no spillway type listed, it does have a spillway width of 206 feet. The surrounding area has a drainage area of 6.92 square miles, making Fox Lake Dam a critical water resource for the region.

For water resource and climate enthusiasts, Fox Lake Dam serves as a fascinating example of early 20th-century engineering and its ongoing impact on local water management. With its recreational focus and state regulation, the dam stands as a reminder of the delicate balance between human development and environmental stewardship in the face of changing climate conditions.