Located in Atchison, Kansas, Gsd No B-21 (Gc 23) is a debris control dam owned by the local government and regulated by the Kansas Department of Agriculture. The dam, designed by USDA NRCS, serves a primary purpose of debris control and is classified as an Earth dam with a buttress core type. With a height of 31.8 feet and a storage capacity of 287 acre-feet, the dam plays a crucial role in managing water resources in the area.

Despite being rated as having a low hazard potential, Gsd No B-21 (Gc 23) is considered to have moderate risk, with a moderate risk assessment score of 3. The dam has a spillway width of 40 feet and a maximum discharge capacity of 1100 cubic feet per second. Although the dam has not been recently inspected and its condition is not rated, it is equipped with uncontrolled spillways and has a storage capacity of 287 acre-feet, providing important flood control benefits for the local community.

While the dam does not have outlet gates, locks, or associated structures, it covers a surface area of 8 acres and has a drainage area of 0.75 square miles. The dam is situated in the Rock Island District and falls under the jurisdiction of the Kansas state regulatory agency. With a focus on debris control and flood management, Gsd No B-21 (Gc 23) plays a critical role in ensuring the safety and security of water resources in the region.