Hanigan Dam, located in Monona County, Iowa, is a private-owned structure designed by NRCS with a primary purpose of fire protection, stock, or small fish pond. Completed in 2001, this earth dam stands at a height of 44 feet and spans a length of 720 feet, with a storage capacity of 62 acre-feet. The dam is situated on TR-Willow Creek and is regulated by the Iowa Department of Natural Resources.

With a low hazard potential and a moderate risk assessment rating, Hanigan Dam serves as a crucial water resource for the surrounding area. Its surface area of 4.2 acres and drainage area of 0.43 square miles make it a valuable asset for water management and conservation efforts. Despite its low hazard potential, the dam is equipped with an uncontrolled spillway and is subject to regular state inspections, ensuring its structural integrity and safety.

Hanigan Dam not only provides essential fire protection and water storage capabilities but also supports the local ecosystem by serving as a habitat for small fish and wildlife. Its strategic location in Missouri Valley contributes to the overall water infrastructure in the region, making it a significant asset for water resource and climate enthusiasts to study and appreciate.