Mc Donald Subwatershed 4-2557 is a local government-owned structure located in Woodbury, Iowa, specifically in the city of Rodney along the TR- Little Sioux River. Designed by the USDA NRCS and completed in 1960, this earth dam serves multiple purposes including fire protection, stock, small fish pond, and flood risk reduction. With a dam height of 44 feet and a storage capacity of 18 acre-feet, it covers a surface area of 1 acre and drains a small area of 0.11 square miles.

Despite its low hazard potential, Mc Donald Subwatershed 4-2557 carries a moderate risk rating due to its location and design characteristics. While the dam is not currently rated in terms of condition assessment, it is regulated by the Iowa Department of Natural Resources and subject to state permitting, inspection, and enforcement. With its uncontrolled spillway type and soil foundation, the structure remains an important asset for water resource management in the region, highlighting the intersection of water conservation, climate resilience, and community safety.