Twin Lake, located in Alpine County, California, is a privately owned reservoir with a primary purpose of hydroelectric power generation. Built in 1903, this earth dam stands at 22 feet high and spans 1520 feet in length. With a storage capacity of 21,581 acre-feet, it serves as a crucial water resource for the surrounding area, particularly during dry seasons. The dam is regulated by both state and federal agencies, ensuring its safety and compliance with inspection and enforcement protocols.

The North Fork Mokelumne River-tr flows through Twin Lake, providing a source of water for the reservoir. The dam's spillway, with a width of 296 feet, is uncontrolled and can handle a maximum discharge of 12,400 cubic feet per second. Despite its low hazard potential, Twin Lake is subject to moderate risk assessment due to its age and condition assessment being unavailable. Emergency action plans have been prepared and revised periodically, with maintenance measures in place to mitigate any potential risks associated with the dam's operation.

The picturesque setting of Twin Lake, nestled in the scenic Kirkwood area, offers not only a source of hydroelectric power but also a recreational spot for visitors to enjoy. With its historical significance dating back over a century, Twin Lake stands as a testament to the intersection of water resource management, climate resilience, and sustainable energy generation in the California landscape.