Upper Rock Lake Auxiliary, a private water resource structure located in Nevada, California, serves as a vital component for hydroelectric purposes. Built in 1855, this earth dam stands at a height of 8.5 feet and has a storage capacity of 190 acre-feet, with a surface area of 0.06 square miles and a drainage area of 0.1 square miles. The dam's spillway, with a width of 5 feet, is uncontrolled, and the structure has a low hazard potential.

Managed by the Federal Energy Regulatory Commission, Upper Rock Lake Auxiliary is regulated by the California Department of Water Resources for safety and inspection purposes. Despite its age, the dam's risk assessment categorizes it as moderate, with a score of 3 out of 5. The last inspection took place in August 2016, and an Emergency Action Plan revision occurred in October 2020. While the condition assessment is currently unavailable, the dam continues to play a crucial role in water resource management and climate resilience efforts in the region.