West Sunnyside Watershed Site C-6 in Plymouth County, Iowa is a carefully designed earth dam constructed in 1970 by the USDA NRCS with a primary purpose of providing fire protection, stock, or small fish pond. The dam stands at a height of 33 feet, stretches 1380 feet in length, and has a storage capacity of 127 acre-feet, with a normal storage of 43 acre-feet. Situated along TR-BROKEN KETTLE CREEK in Sioux City, this watershed site covers a surface area of 8.2 acres and serves a drainage area of 0.5 square miles.

Managed under the jurisdiction of the Iowa DNR, West Sunnyside Watershed Site C-6 is regulated, permitted, inspected, and enforced by state authorities to ensure its safety and functionality. Despite having a low hazard potential, the dam's condition has not been rated, and its risk assessment is considered moderate. While the emergency action plan status and risk management measures are not specified, the site is equipped with an uncontrolled spillway and is designed to reduce flood risk in the area. As a vital water resource infrastructure, this dam plays a crucial role in maintaining water supply and protecting the surrounding community from potential disasters.