O Brien Dam, located in Diamondhead Lake, Iowa, serves multiple purposes including fire protection and creating a stock or small fish pond. Built in 1989, this earth dam stands at a height of 33 feet and spans 250 feet in length, with a storage capacity of 36 acre-feet. The dam is regulated by the Iowa Department of Natural Resources and is regularly inspected to ensure its safety and compliance with state regulations.

Despite being categorized as a low hazard potential structure, O Brien Dam is considered to have a moderate risk level due to its location and design. The dam's spillway type is uncontrolled, with no outlet gates or locks present. The surrounding area has a drainage area of 0.16 square miles, providing a surface area of 1.9 acres. While the dam has not been rated for its condition assessment, it is actively managed to mitigate any potential risks and ensure the safety of the community.

In the event of an emergency, O Brien Dam does not currently have an Emergency Action Plan (EAP) in place, but efforts are made to adhere to guidelines and assess the risk management measures. With its crucial role in providing water resources and maintaining ecological balance in the area, O Brien Dam stands as a testament to responsible water management practices and the importance of sustainable infrastructure development in the face of changing climate conditions.