Willow Lake #1, located in Napa, California, is a privately owned earth dam completed in 2004 for flood risk reduction along the Tr Napa River. Standing at a height of 40 feet with a hydraulic height of 34 feet, this dam has a storage capacity of 89 acre-feet and covers a surface area of 6 acres. Despite its high hazard potential, the dam is currently in satisfactory condition and has been regularly inspected by the California Department of Water Resources.

The primary purpose of Willow Lake #1 is flood risk reduction, but it also serves for irrigation and water supply in the region. With its proximity to the Napa River, the dam plays a crucial role in managing water resources and protecting the surrounding areas from potential flooding events. The dam has state jurisdiction, permitting, inspection, and enforcement, ensuring its compliance with safety regulations and standards to safeguard the community and the environment.

Led by its primary owner, this dam continues to play a vital role in the water resource management of Napa County. With a solid foundation and a robust structure, Willow Lake #1 stands as a testament to the importance of sound infrastructure in mitigating flood risks and ensuring water supply for agricultural and urban needs in the region. As climate change poses new challenges to water management, the significance of dams like Willow Lake #1 only grows, highlighting the essential role they play in adapting to a changing climate and safeguarding water resources for future generations.