Alpine Auxiliary No. 3, located in Dorrington, California, is a privately owned rockfill dam completed in 1891 for hydroelectric purposes. With a height of 42 feet and a storage capacity of 4,300 acre-feet, this dam serves multiple functions including hydroelectric power generation, recreation, and water supply. Situated on Silver Creek, the dam has a low hazard potential and is regulated by both state and federal agencies, with inspection and enforcement measures in place to ensure its safety and compliance.

Managed by the Federal Energy Regulatory Commission, Alpine Auxiliary No. 3 is part of a network of three associated structures in the area. Its uncontrolled spillway and moderate risk assessment highlight the need for ongoing monitoring and risk management measures. Despite its age, the dam continues to provide essential services to the community while being subject to regular state inspections and regulatory oversight. With its historical significance and contributions to water resource management, Alpine Auxiliary No. 3 remains an important piece of California's infrastructure.

As a key component of the water supply and energy infrastructure in Alpine County, Alpine Auxiliary No. 3 plays a crucial role in supporting the region's water needs and power generation capacity. Its location within the San Francisco District and proximity to Tom McClintock's congressional district underscore its importance in the local and state landscape. With its storied past and ongoing relevance in the present day, this dam serves as a testament to the enduring impact of water resource management and climate resilience efforts in California.