Johnson Dam, located in Monona, Iowa, serves multiple purposes including fire protection, stock maintenance, and providing a small fish pond. Constructed in 2008 by the NRCS, this privately owned earth dam stands at a height of 27 feet and has a length of 215 feet. With a storage capacity of 138 acre-feet and a normal storage of 58 acre-feet, the dam covers a surface area of 6.8 acres and drains a 0.97 square mile area.

The dam, situated on TR-Jordan Creek, is regulated by the Iowa DNR and undergoes regular state inspections and enforcement to ensure its safety and compliance. With a low hazard potential and a moderate risk assessment rating of 3, Johnson Dam is deemed to be in good condition but has not been rated officially. The spillway, which is uncontrolled and 3 feet wide, helps manage water flow during periods of high precipitation.

Overall, Johnson Dam provides vital water resource management functions while also offering recreational opportunities for the local community. Its strategic location and design make it a crucial asset for maintaining water quality, ensuring public safety, and supporting ecological diversity in the region.