Deer Lake, located in Angwin, California, is a privately owned earth-type dam that was completed in 1958 for the primary purpose of water supply. With a dam height of 72 feet and a hydraulic height of 62.7 feet, Deer Lake has a storage capacity of 248 acre-feet and covers a surface area of 10 acres. The dam sits on Tr Angwin Creek and is regulated by the California Department of Water Resources (DWR) for safety and inspection.

Despite its small size in terms of storage and drainage area, Deer Lake poses a high hazard potential and is subject to regular inspections to ensure its structural integrity. The dam's condition assessment in 2017 deemed it satisfactory, and emergency action plans are in place to mitigate potential risks. The surrounding area offers opportunities for irrigation, recreation, and of course, water supply, making Deer Lake an important resource in the region for both residents and wildlife alike.

With its picturesque location in Napa County, Deer Lake serves as a vital water source for the community of Angwin and beyond. As climate change continues to impact water resources, the maintenance and regulation of dams like Deer Lake become increasingly crucial for ensuring a sustainable water supply for future generations. As enthusiasts of water resources and climate conservation, it is essential to monitor and support efforts to safeguard and enhance the resilience of dams like Deer Lake in the face of changing environmental conditions.