Big Coon Subwatershed Site M-5 is a local government-owned flood risk reduction structure located in Anthon, Iowa, along Coon Creek. Designed by USDA NRCS, this Earth dam stands at 20 feet tall and stretches 565 feet in length, with a storage capacity of 52 acre-feet. Completed in 2000, the dam serves multiple purposes including fire protection, stock or small fish pond, and flood risk reduction for the surrounding area, covering a drainage area of 3.57 square miles.

With a low hazard potential and a moderate risk assessment rating, Big Coon Subwatershed Site M-5 is regulated by the Iowa Department of Natural Resources. The dam is inspected, permitted, and enforced by state agencies, ensuring its structural integrity and safety measures are up to standard. Although the condition assessment is currently marked as "Not Rated," the site's risk management measures are in place to address any potential issues that may arise.

Despite being uncontrolled, the spillway type of this dam is designed to handle any excess water during heavy rainfall events, with a surface area of 1.2 acres. Located within the Rock Island District, this structure plays a critical role in managing water resources in the region and highlights the collaborative efforts between local and federal agencies in safeguarding communities from flood risks and ensuring sustainable water management practices.