Big Wyacondah Watershed Site 21b in Iowa is a local government-owned dam designed by USDA NRCS for purposes such as fire protection, stock, or small fish pond, and flood risk reduction. Completed in 1976, this earth dam stands at a height of 27 feet and spans a length of 524 feet. With a storage capacity of 199 acre-feet and a drainage area of 0.55 square miles, the dam serves the TR South Wyacondah river/stream and is regulated by the Iowa Department of Natural Resources.

The dam's hazard potential is classified as low, with a moderate risk assessment rating. Despite its age, the condition assessment of the dam is not rated, indicating a need for further evaluation. The emergency action plan (EAP) status, along with other risk management measures and inundation maps, is currently not available. This site provides valuable data for water resource and climate enthusiasts interested in the management and functionality of dams in the region, highlighting the importance of ongoing maintenance and assessment to ensure public safety and environmental protection.