Diehl Dam, located in Ringgold County, Iowa, is a privately owned structure with a primary purpose of fire protection, stock, or small fish pond. Built in 1991 by USDA NRCS, this earth dam stands at a height of 31 feet and spans 425 feet in length. It holds a storage capacity of 57 acre-feet and covers a surface area of 3.3 acres, serving as a vital water resource for the area.

Managed by the Iowa Department of Natural Resources, Diehl Dam is regulated, permitted, inspected, and enforced to ensure its safety and compliance with state guidelines. Despite being classified as low hazard potential, the dam is considered to have a moderate risk level (3) according to a risk assessment. It features an uncontrolled spillway and is situated along TR-Walnut Creek, serving as a crucial component for water management and conservation in the region.

For water resource and climate enthusiasts, Diehl Dam presents an intriguing case study in dam infrastructure and management. With its diverse purposes and design by the USDA NRCS, this structure highlights the importance of water storage for fire protection and agricultural needs. As an integral part of the local ecosystem, Diehl Dam plays a significant role in maintaining water quality and supporting wildlife habitats along the Walnut Creek watershed.