Herrick, located in Converse, Wyoming, is a privately owned irrigation dam constructed in 1946 by designer Albert B. Bartlett. This Earth-type dam on Twenty Mile Creek stands at 30 feet in height and 550 feet in length, with a storage capacity of 146 acre-feet. Despite its low hazard potential and fair condition assessment, the dam is state regulated and regularly inspected, with state permitting, inspection, and enforcement all in place to ensure its safety and compliance with regulations.

Managed by the Wyoming state agency SEO, Herrick serves the primary purpose of irrigation and has a spillway width of 100 feet for uncontrolled water release. With a moderate risk assessment rating, the dam is located in Edgemont, South Dakota, within the Congressional District 00 of Wyoming, represented by Congresswoman Liz Cheney. While the dam has a drainage area of 0 square miles and a surface area of 10 acres, it plays a crucial role in water resource management and agriculture in the region.

Despite its age, Herrick continues to support local agriculture and water supply needs, demonstrating the importance of proper dam maintenance and regulation in ensuring the sustainability of water resources. As a key structure on Twenty Mile Creek, this irrigation dam highlights the intricate balance between human development and environmental conservation in the face of changing climate patterns and increasing water demands.