Oneal Lake is a privately owned reservoir located in Yavapai, Arizona, with a primary purpose of irrigation. Built in 1894, the earth dam stands at a height of 9.7 meters and has a length of 560 meters, providing a storage capacity of 88.9 acre-feet. The reservoir covers a surface area of 13.4 acres and is regulated by the Arizona Department of Water Resources, with state permitting, inspection, and enforcement in place to ensure its safety and compliance.

Despite being classified as having a low hazard potential, Oneal Lake is considered to have a moderate risk level, with a risk assessment rating of 3. The spillway type is uncontrolled with a width of 23 meters, and the dam is designated as a buttress earth structure. The last inspection of the reservoir was conducted in May 2020, with a scheduled inspection frequency of every 5 years. While the condition assessment is currently not rated, the reservoir is under state jurisdiction and meets regulatory guidelines for operation and management.

Water resource and climate enthusiasts may find Oneal Lake to be an intriguing case study in irrigation infrastructure, showcasing historical engineering practices and the ongoing efforts to maintain dam safety and compliance with state regulations. The reservoir's location in a picturesque setting in Yavapai, Arizona, provides a unique opportunity to explore the intersection of water management, environmental stewardship, and sustainable agriculture in the arid southwestern United States. With its rich history dating back to the late 19th century, Oneal Lake serves as a vital water source for agricultural activities in the region, highlighting the importance of responsible water resource management in the face of changing climate conditions.