Big Coon Subwatershed Site 3a-4, located in Anthon, Iowa, is a significant earth dam constructed in 1999 by the USDA NRCS to serve multiple purposes such as fire protection, stock, small fish pond, and flood risk reduction. This dam has a height of 36 feet and a length of 457 feet, with a storage capacity of 78 acre-feet and a surface area of 3.5 acres. It is regulated and inspected by the Iowa DNR, ensuring its safety and compliance with state regulations.

The dam's primary purpose is to provide essential water resources for the surrounding area while also offering flood risk reduction measures. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated, highlighting the need for ongoing monitoring and maintenance. The presence of uncontrolled spillways indicates a careful balance between storage capacity and controlled water release to prevent potential flooding events.

With its location on TR- BIG CREEK and proximity to Woodbury County, Big Coon Subwatershed Site 3a-4 serves as a vital water management structure designed to enhance the local ecosystem and protect against potential water-related hazards. Its construction by the USDA NRCS underscores a commitment to sustainable resource management and climate resilience in the region. As a focal point for water resource and climate enthusiasts, this site offers a fascinating glimpse into the intersection of engineering, environmental conservation, and community safety.