Arp Dam, located in Johnson County, Iowa, is a privately owned earth dam constructed in 1970 by the USDA NRCS. With a height of 31 feet and a length of 322 feet, the dam serves multiple purposes including fire protection, stock, small fish pond, and recreation. The dam has a storage capacity of 42 acre-feet and covers a surface area of 2.9 acres, with a drainage area of 0.13 square miles.

Managed by the Iowa Department of Natural Resources, Arp Dam is regulated, permitted, inspected, and enforced by state authorities to ensure its safety and functionality. The dam has a low hazard potential and a moderate risk rating, making it a key infrastructure for water resource management in the area. Despite not being rated for its condition, the dam continues to provide essential services to the community, including water storage and environmental conservation along the TR-Knapp Creek.

In the event of an emergency, the dam's emergency action plan and risk management measures are crucial for ensuring public safety and minimizing potential risks. With its strategic location and design, Arp Dam plays a significant role in supporting water supply, recreational activities, and wildlife habitat preservation in the Coralville Reservoir area.