Green Castle Dam, located in Marshall County, Iowa, is a local government-owned structure on the TR-Brush Creek that serves primarily for recreational purposes. Built in 1954 by CLAPSADDLE-GARBER, this earth dam stands at a height of 30 feet and spans 650 feet in length, with a storage capacity of 263 acre-feet. Despite its uncontrolled spillway type and significant hazard potential, the dam's condition assessment remains satisfactory as of the last inspection in June 2020.

With its location in Ferguson, Iowa, the Green Castle Dam offers a serene setting for water resource and climate enthusiasts to explore. The dam's stone core and soil foundation contribute to its structural integrity, while the surrounding area boasts a surface area of 17 acres and a drainage area of 0.44 square miles. While the dam has not undergone significant modifications over the years, it is subject to regular inspections by the Iowa Department of Natural Resources to ensure compliance with state regulations and enforcement.

In the event of emergencies, the dam's risk assessment is categorized as moderate, with a designated inspection frequency of 5 years. While an Emergency Action Plan (EAP) is not currently prepared, the dam's risk management measures aim to mitigate potential hazards and ensure public safety. Overall, Green Castle Dam stands as a vital recreational asset in the region, showcasing the intersection of water resource management and environmental stewardship.