Upper Twin Lake is a privately owned water resource located in Bridgeport, California, within the Mono County. The dam, completed in 1905, stands at a height of 14 feet and serves primarily for irrigation and water supply purposes. With a storage capacity of 2070 acre-feet and a surface area of 286 acres, Upper Twin Lake is a vital source of water for the surrounding area. The dam is regulated and inspected by the California Department of Water Resources to ensure its safety and compliance with state regulations.

Situated along Robinson Creek, Upper Twin Lake has a drainage area of 30.05 square miles and a hydraulic height of 11 feet. Despite being classified as having a high hazard potential, the dam's condition is assessed as fair as of September 2017, with regular inspections carried out to ensure its integrity. The emergency action plan for the dam was last revised in August 2019, indicating proactive measures in place to mitigate potential risks and ensure the safety of the surrounding community in case of emergencies. Enthusiasts of water resources and climate will find Upper Twin Lake an intriguing case study of sustainable water management in a region prone to drought and water scarcity challenges.