Johnson Dam, located in Princeton, MO, is a privately owned structure designed by USDA NRCS to regulate the TR-Weldon River in Iowa. Completed in 1974, this earth dam stands at a height of 32 feet and spans 370 feet in length, with a storage capacity of 59 acre-feet. Its primary purpose is to provide water supply for the surrounding area, with a low hazard potential and moderate risk assessment.

The dam is under the regulatory jurisdiction of the Iowa DNR and undergoes regular inspections, permitting, and enforcement to ensure its structural integrity and safety. Although the dam is not rated for its condition assessment, it is considered to meet guidelines for emergency action planning and risk management measures. The surrounding area benefits from the dam's water storage capabilities, especially during times of water scarcity or drought.

With its strategic location and efficient design, Johnson Dam plays a crucial role in water resource management and climate resilience in Decatur County, Iowa. As a key piece of infrastructure in the Rock Island District, this dam serves as a vital asset for water supply and flood control, highlighting the importance of sustainable water management practices in the region.