The eel watershed (HUC 05120203) covers approximately 3,600 square miles in northwestern California. The region is known for its diverse aquatic species, including salmon, steelhead, and Pacific lamprey. The watershed is characterized by a Mediterranean climate, with hot, dry summers and mild, wet winters. Snowpack in the region varies depending on elevation and can greatly influence water supply. The surface water in the watershed is sourced primarily from the Eel River, which flows through the region before emptying into the Pacific Ocean. There are several reservoirs within the watershed, including Lake Pillsbury and Lake Mendocino. The area has experienced significant drought in recent years, with some of the driest years on record occurring in the early 2010s. Overall, the eel watershed is a unique and ecologically important region that plays a crucial role in California's water supply and aquatic biodiversity.