Henco Dam, located in Union County, Iowa, was completed in 1982 and is owned by a private entity. The dam, designed by USDA NRCS, serves multiple purposes including fire protection, stock, and small fish pond. With a height of 28 feet and a length of 310 feet, Henco Dam has a storage capacity of 28 acre-feet and covers a surface area of 2.2 acres.

Managed by the Iowa Department of Natural Resources, Henco Dam is classified as a low hazard potential structure with a moderate risk rating. The dam is constructed of earth and sits on a soil foundation, regulating the flow of the TR-TWOMILE CR. river/stream. Although not currently rated for condition assessment, Henco Dam is inspected, permitted, and regulated by state authorities, ensuring its safety and compliance with environmental standards.

Henco Dam, situated in Thayer, Iowa, is an essential asset for water resource management in the region. With its strategic location and multiple functions, including fire protection and stock pond, the dam plays a crucial role in maintaining water quality and availability. Climate and water resource enthusiasts can appreciate the engineering behind Henco Dam and its contribution to the sustainable use of water for various purposes in Union County.