Black Reservoir, also known as Junction Reservoir, is a privately owned water storage facility located in Sonora Junction, California. Built in 1905, this earth dam stands at 18 feet tall and spans a length of 1330 feet, with a storage capacity of 185 acre-feet. The reservoir serves primarily for irrigation and water supply purposes, drawing water from Black Creek to support agricultural activities in the area.

Managed by the California Department of Water Resources (DWR) and the Safety of Dams, Black Reservoir is subject to state regulations, permitting, inspection, and enforcement to ensure its safe operation. Despite its low hazard potential and satisfactory condition assessment, regular inspections are conducted to maintain the reservoir's integrity. The dam has a spillway type and width unspecified, but with a drainage area of 0.2 square miles, it plays a crucial role in managing water resources in the region.

Situated in Mono County, California, Black Reservoir offers a vital water storage solution for the surrounding community. With its historical significance and ongoing state oversight, this reservoir stands as a testament to sustainable water management practices in the face of a changing climate. For water resource and climate enthusiasts, Black Reservoir serves as a fascinating example of how private ownership and state regulation can work together to ensure the reliability and safety of essential water infrastructure.