Dd No 121 (Depoe), also known as Deer Creek WS Joint District No 55, is a local government-owned structure in Lone Elm, Kansas, designed by USDA NRCS. This dam is regulated by the Kansas Department of Agriculture and serves the primary purpose of flood risk reduction along the Deer Creek-TR. With a height of 20 feet and a storage capacity of 425.09 acre-feet, Dd No 121 plays a crucial role in managing water resources and protecting the surrounding area from potential flooding events.

Constructed with an earth core and buttress type, Dd No 121 has a relatively low hazard potential and a moderate risk assessment ranking. The dam features an uncontrolled spillway with a width of 129 feet and a maximum discharge of 782 cubic feet per second. Despite not being rated for its condition, Dd No 121 has not been inspected since December 1999. While the dam has not undergone modifications in recent years, it remains a key infrastructure for water resource management in Anderson County, Kansas.

As water resource and climate enthusiasts continue to monitor and assess the impact of dams like Dd No 121 on local ecosystems and communities, ensuring the safety and effectiveness of such structures becomes paramount. With its strategic location and design characteristics, Dd No 121 stands as a testament to the collaborative efforts of federal and state agencies in managing flood risks and safeguarding water resources in the region.