Murphy is a privately owned dam located in Johnson, Wyoming, specifically in the city of Arvada. Built in 1970 by designer Clifford J Sanders, this earth dam serves multiple purposes including fire protection, stock, and small fish pond management. The structure stands at 25 feet tall with a hydraulic height of 20 feet and a length of 620 feet, providing a storage capacity of 112 acre-feet. Despite its low hazard potential, the dam's condition assessment is rated as poor, indicating a need for maintenance and repair.

Situated on Murphy Draw, a river/stream in the area, the dam's primary purpose is to serve the local community's water needs while also supporting wildlife and ecosystem functions. Although the dam is state-regulated and inspected regularly, its risk assessment is moderate due to its poor condition. The spillway, with a width of 24 feet, is uncontrolled, posing potential risks in case of high water levels. With Liz Cheney as the Congressional Representative overseeing the area, attention to the dam's maintenance and risk management is crucial to ensure the safety and sustainability of water resources in the region.