Heishman Dam, located in Marengo, Iowa, is a privately owned earth dam constructed in 2017 for the primary purpose of recreation. The dam stands at a height of 40 feet and has a length of 340 feet, creating a reservoir with a storage capacity of 112 acre-feet. Situated on a tributary to Walnut Creek, the dam covers a surface area of 7.3 acres and serves as a popular spot for outdoor activities such as fishing, boating, and picnicking.

Managed and regulated by the Iowa Department of Natural Resources, Heishman Dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. The dam features a spillway width of 40 feet and is inspected, permitted, and enforced by the state authorities to ensure its safety and functionality. With its serene surroundings and ample recreational opportunities, Heishman Dam is a vital water resource for the community and a picturesque destination for water resource and climate enthusiasts to explore and appreciate.