Three Mile Reservoir Dam, located in Westerville, Iowa, is a state-owned dam that serves multiple purposes, including flood risk reduction, recreation, and water supply. Completed in 1995, this earth dam stands at a height of 63 feet and spans a length of 1850 feet, with a storage capacity of 29,950 acre-feet. Situated on Three Mile Creek, the dam plays a crucial role in managing water resources in Union County, Iowa.

Managed by the Iowa Department of Natural Resources, the dam is regularly inspected and maintained to ensure its structural integrity and safety. With a significant hazard potential and a moderate risk assessment rating, the dam is considered satisfactory in its condition, with a five-year inspection frequency. The dam's spillway type is uncontrolled, with a width of 6 feet, providing an essential release mechanism for excess water during times of high flow.

As an integral part of the water management infrastructure in the region, Three Mile Reservoir Dam stands as a testament to the importance of flood risk reduction and water supply management. With its strategic location and design, the dam continues to play a vital role in protecting the community from potential flooding events while also providing opportunities for recreation and ensuring a stable water supply for the area.