Porter Dam in Altoona, Iowa, is a privately owned earth dam that was completed in 1955 for recreation purposes along the East Fourmile Creek. With a height of 25 feet and a length of 150 feet, this dam has a storage capacity of 51 acre-feet and covers a surface area of 2.6 acres. While it has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, the dam is regulated by the Iowa Department of Natural Resources and undergoes regular inspections, permitting, and enforcement to ensure its safety and compliance with state regulations.

Located in Polk County, Porter Dam is managed for recreational use and provides a scenic spot for outdoor enthusiasts to enjoy fishing, hiking, and other activities along the East Fourmile Creek. While the dam does not have a controlled spillway, it is designed to handle moderate risk situations with a designated Emergency Action Plan in place. The dam is situated in a strategic location within the Rock Island District and is part of the local watershed, serving as a vital infrastructure for water resource management in the area.

Overall, Porter Dam plays a crucial role in providing recreational opportunities and managing water resources in the Altoona area. With its historical significance dating back to the 1950s, the dam continues to be a focal point for outdoor recreation and serves as a reminder of the importance of maintaining and regulating our water infrastructure for the benefit of both local communities and the environment.