Located in Woodbury County, Iowa, the Parnell Creek Subwatershed Site 21-1 is a local government-owned earth dam completed in 1967 by USDA SCS. With a primary purpose of fire protection, stock, or small fish pond, this structure also serves for flood risk reduction. The dam has a height of 34 feet and a storage capacity of 50 acre-feet, with a surface area of 2.8 acres and a drainage area of 0.16 square miles.

Managed by the Iowa Department of Natural Resources, this dam is regulated and inspected regularly to ensure its safety and functionality. With a low hazard potential and a moderate risk assessment rating, the Parnell Creek Subwatershed Site 21-1 plays a vital role in protecting the surrounding community and natural resources. Although the dam's condition assessment is currently not rated, its critical role in water resource management cannot be understated for water resource and climate enthusiasts in the area.