Watershed
The roughly 800-square-mile (2,100 km2) watershed of the Shasta River consists of a semi-arid farming valley entirely in Siskiyou County. It is adjacent to the Scott River on the west, Butte Creek on the east, and the main Klamath River on the north. The watershed is located east of the Klamath Mountains and northeast of Mount Shasta. Some towns in the watershed include Weed, Edgewood, Gazelle, Big Springs, Grenada, Montague, and Yreka. Major bodies of water include Lake Shastina, Dwinnell Reservoir and Trout Lake.
Receiving just 14 inches (36 cm) of rain yearly on average, the 30-mile (48 km)-wide Shasta River Valley receives most of its surface water flow from groundwater, and now, agricultural return flows. It also receives some water from snow runoff at Mount Shasta - which flows out of lava tubes as springs and feeds east-side Shasta River tributaries such as Big Springs Creek.
Read more about this topic: Shasta River