Downing Dam, located in Union, Iowa, is a privately owned structure designed by the USDA NRCS and regulated by the Iowa DNR. Completed in 1994, the dam serves multiple purposes including fire protection and as a stock or small fish pond. With a height of 25 feet and a length of 407 feet, Downing Dam has a storage capacity of 64 acre-feet and a surface area of 4 acres, providing valuable water resources for the surrounding area.

The dam's low hazard potential is complemented by a moderate risk assessment, indicating a level of safety and security for the community. While the condition assessment is currently not rated, the dam is regularly inspected, maintained, and regulated by state authorities to ensure its structural integrity and functionality. With its strategic location on TR- Threemile Creek, Downing Dam plays a crucial role in water management and conservation efforts in the region, highlighting its significance for water resource and climate enthusiasts.

Despite its uncontrolled spillway type, Downing Dam's design and construction by the Natural Resources Conservation Service reflect a commitment to sustainable water management practices. The dam's proximity to Talmage and its association with fire protection and fisheries underscore its importance in supporting local ecosystems and agricultural activities. As a notable feature in the Rock Island District, Downing Dam stands as a testament to effective collaboration between private ownership, federal agencies, and state regulators in safeguarding water resources and enhancing climate resilience in Union, Iowa.