Fern Lake, located in El Verano, Sonoma, California, is a state-regulated reservoir with a primary purpose of water supply for irrigation and other uses. Completed in 1921, this earth dam stands at a height of 40 feet and has a hydraulic height of 36 feet, with a capacity of 241 acre-feet of water storage. The reservoir covers a surface area of 14 acres and is fed by Tr Mill Creek, serving as a vital resource in the region.

With a high hazard potential and satisfactory condition assessment, Fern Lake is regularly inspected by the state regulatory agency to ensure its safety and compliance with regulations. The dam has a history of meeting guidelines and preparedness for emergencies, with the last inspection conducted in January 2021. In the event of any risks or emergencies, appropriate risk management measures are in place to mitigate potential hazards and ensure the safety of the surrounding community.

Fern Lake's important role in water supply and its strategic location in the Sacramento District make it a key asset in managing water resources in the region. As a state-regulated structure, it plays a crucial role in irrigation and water supply, highlighting the importance of sustainable water management practices in the face of changing climate conditions.