Big Aso, also known as Big Aso Tank, is a privately-owned water resource located in Coconino, Arizona. This reservoir serves multiple purposes including fire protection, stock, and small fish pond usage. Managed by the Arizona Department of Water Resources, Big Aso is regulated, permitted, inspected, and enforced to ensure its safety and compliance with state water laws.

Constructed as an earth dam with a height of 16.4 feet and a length of 374 feet, Big Aso has a storage capacity of 95.3 acre-feet and covers a surface area of 17.43 acres. The reservoir is equipped with an uncontrolled spillway and has a low hazard potential, rated as moderate in terms of risk assessment. Although last inspected in 2012, with a scheduled inspection frequency of 5 years, the condition assessment of Big Aso is currently not rated.

Water resource and climate enthusiasts interested in the management and operation of dams will find Big Aso an intriguing case study. With its unique purpose and design features, this reservoir in Arizona offers insights into the regulatory processes, risk assessments, and safety measures involved in maintaining water infrastructure for multiple uses.