J. N. Mertz is a privately owned earth dam located in Torrington, Wyoming, along the Laramie River offstream. Built in 1903 for irrigation purposes, this dam stands at a height of 13 feet with a hydraulic height of 11 feet and a length of 1590 feet. It has a storage capacity of 156 acre-feet and a surface area of 20 acres, serving as a vital resource for water management in the area.

Despite its age, J. N. Mertz faces some challenges with a poor condition assessment as of September 2017 and a low hazard potential. It is regulated by the Wyoming State Engineer's Office with state-permitting, inspection, and enforcement in place. The dam has uncontrolled spillways and outlet gates for water release, with a moderate risk assessment indicating the need for continued monitoring and potential risk management measures.

Although J. N. Mertz plays a crucial role in irrigation systems in the region, its poor condition assessment and moderate risk assessment highlight the importance of ongoing maintenance and monitoring to ensure the safety and efficiency of this essential water resource infrastructure. Water resource and climate enthusiasts can appreciate the historical significance and current challenges facing this dam in maintaining water supply and management for agricultural purposes in Wyoming.