The Eel River is a federally designated Wild and Scenic River that flows generally north and west through the California Coast Range, emptying into the Pacific Ocean about 10 miles (16 km) south of Humboldt Bay. Petroglyphs indicate that Native tribes may have occupied the Eel River watershed for more than 2500 years. The first European explorers arrived in the early 17th century and found the area was home to at least four different tribes. The river was named in 1850 during the California Gold Rush by an exploring party that traded supplies with local fisherman in return for a large number of Pacific lamprey, which they mistook for eels. There are two hydroelectric dams on the Eel, the Scott Dam that forms Lake Pillsbury, and the Cape Horn Dam that forms Van Arsdale Reservoir. At Cape Horn Dam, the majority of the water is diverted through a tunnel and hydroelectric plant, and then through a 1 mile (1.6 km) tunnel to the headwaters of the Russian River to provide water for Mendocino and Sonoma Counties. The river discharge is related to the seasonal climate which is highly variable, with average flows in the winter over 100 times greater than in summer. The watershed supports abundant forests – including some of the world's largest redwood trees and historically was an important salmon spawning river. The Eel River has a very high suspended sediment concentration due to the regional geology, landslides, seismic activity, and human development such as logging, grazing, and road-building that significantly affect the watershed ecology. Read more about the Eel River here and here. Click here to explore more of the Eel River and the coast of Humboldt County.