Upper Rock Lake Main in California is a privately owned dam regulated by the Department of Water Resources (DWR) for the safety of dams. Completed in 1855, this earth dam stands at 17 feet high and serves primarily for hydroelectric purposes. Located in Nevada County, the dam impounds Texas Creek 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.

Despite its low hazard potential, Upper Rock Lake Main is under the oversight of the Federal Energy Regulatory Commission for inspections and regulatory measures. The dam has not been assessed for its current condition, but an Emergency Action Plan (EAP) was last revised in October 2020. With a high risk assessment score of 2, there are likely management measures in place to ensure the safety and integrity of the structure in the event of an emergency.

Water resource and climate enthusiasts interested in the history and details of Upper Rock Lake Main will find its location, design, and operational characteristics intriguing. As a part of the hydroelectric infrastructure in the region, this dam plays a crucial role in water management and energy production, contributing to the overall resilience of the water resource system in the area.