Nelson Dam, located in Gillett Grove, Iowa, is a privately owned earth dam constructed in 1999 by the NRCS for grade stabilization on TR-ELK CREEK. With a height of 26 feet and a length of 314 feet, the dam has a storage capacity of 37 acre-feet and serves the primary purpose of grade stabilization. Despite being uncontrolled, the spillway width of 1 foot ensures the safe release of excess water in case of overflow.

Although the dam is classified as low hazard potential and has not been rated for its condition assessment, it is considered to have moderate risk with a risk assessment score of 3. The dam is not under state regulation, permitting, inspection, or enforcement. However, it plays a crucial role in controlling water flow and protecting the surrounding area from potential flooding. Water resource and climate enthusiasts may find Nelson Dam an intriguing structure due to its unique purpose and design in the conservation and management of water resources in the region.