Pool No. 20, located in Thief River Falls, Minnesota, is a federal-owned water resource structure on the Mud River. Built in 1946, this Earth-type dam stands at a height of 8 feet and spans 4000 feet in length. With a storage capacity of 2815 acre-feet, it serves a primary purpose that is classified as 'Other'.

Despite its low hazard potential, Pool No. 20 plays a vital role in regulating water flow and providing essential water resource management in the region. The dam, which has not been rated for condition assessment, is not state-regulated or permitted, reflecting its federal ownership and management. The structure has not been modified in recent years and lacks certain emergency preparedness features such as an Emergency Action Plan (EAP) or inundation maps.

Pool No. 20 may not be the largest or most high-profile water resource project, but its significance lies in its contribution to water management and regulation in the area. For water resource and climate enthusiasts, understanding the role and operation of structures like Pool No. 20 can provide valuable insights into the intricate network of infrastructure that sustains our waterways and ecosystems.