Tonderum Dam, located in Armstrong, Iowa, was completed in 1970 and is owned by a private entity. The dam, designed by USDA NRCS, serves multiple purposes including fire protection, stock, and small fish pond. With a height of 21 feet and a length of 245 feet, the dam has a storage capacity of 69 acre-feet and covers a surface area of 4.5 acres. It is regulated by the Iowa Department of Natural Resources and undergoes regular inspections and enforcement to ensure its safety and compliance with state regulations.

The dam poses a low hazard potential and has not been rated for its condition assessment. However, it is considered to have a moderate risk level, with a risk assessment score of 3. While the dam has not been modified in recent years, it meets the guidelines for emergency action plans. Despite the absence of inundation maps and specific risk management measures, Tonderum Dam is of interest to water resource and climate enthusiasts due to its location on the TR- East Fork Des Moines River and its role in providing essential resources for the local community.

Overall, Tonderum Dam serves as a crucial infrastructure for water management and conservation in Emmet County, Iowa. Its presence not only supports agriculture and livestock activities but also contributes to fire protection and recreational fishing opportunities. With its earth dam structure and soil foundation, Tonderum Dam stands as a testament to sustainable water resource management and underscores the importance of maintaining and regulating dams for the benefit of both humans and the environment.