of the Klamath Mountains and northwest 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 of rain yearly on average, the -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. Natural History The Shasta River is spawning site for a run of endangered Chinook salmon. Estimates suggest that 80,000 adults fish once returned to the river every year, the largest returning population of any tributary in the Klamath watershed besides the Trinity River Today, less than 10% of this population still returns, and recent droughts have severely hampered survival rates of juvenile fish. The river also supports coho salmon and steelhead. References External links Shasta River Geology Shasta Valley State of California: Shasta River Water Quality Mount Shasta Bioregional Water Center: Dewatering of the Shasta River Mount Shasta Tributaries of the Klamath River Rivers of Siskiyou County, California Shasta-Trinity National Forest Rivers of Northern California