Big Park Watershed Site D-4 in Iowa, managed by the local government, is a key water resource for the area. This earth dam, designed by USDA NRCS in 1960, serves multiple purposes including fire protection, stock, small fish pond, and flood risk reduction. The dam stands at a height of 39 feet and has a storage capacity of 71 acre-feet, with a surface area of 9 acres and a drainage area of 2 acres.

Located in Crawford County, Iowa, the Big Park Watershed Site D-4 is regulated by the Iowa Department of Natural Resources and undergoes regular inspections and enforcement to ensure its safety and functionality. With a low hazard potential and a moderate risk assessment rating, this dam plays a crucial role in water management for the surrounding area. Despite not being rated for condition assessment, the dam is a vital infrastructure for water resource and climate enthusiasts, contributing to the overall environmental health of the region.