 The dams and diversions operated by the Central Valley Project and local irrigation districts control much of the flow in the Sacramento River.Since 1993, to protect the holding and spawning of winter-run Chinook salmon, Reclamation has been required to manage cold-water reservoir storage and releases to maintain daily average water temperatures at or below between Keswick Dam and compliance locations between Balls Ferry and Bend Bridge, from May 15 to September 30.Both Iron Mountain Mine and pyritic ore mining in Shasta County have contributed to the degradation of the Sacramento River, in addition to killing fish and other aquatic organisms downstream of Sacramento River to Keswick Dam.