The construction of the Shasta Dam in the 1930s and ‘40s at the north end of the Sacramento Valley was intended to provide long-term water storage in Shasta Lake, flood control, hydroelectricity and protection against the intrusion of saline water. It is the eighth tallest dam in the United States and has the largest reservoir in California.
The first generators, installed in January 1942, provided the Central Valley Water Project electric power for industrial, agricultural and municipal use. The dam was heavily guarded during World War II as a potentially serious target for enemy assault.
Construction Engineer Ralph Lowery announced through the U.S. Bureau of Reclamation in January 1942 that the latest surveys of power resources in Northern and Central California “indicate the Shasta plant will begin to generate energy just in time to avert an impending power shortage in an area of vital defense production.”
Lowery also noted that in the winter and spring of the previous year, “the unruly Sacramento River inundated the powerhouse foundation 10 separate times,” but with concrete pouring underway, the powerhouse was no longer threatened with flooding.
Source: War Speeds Installation of Shasta Dam Generating System.” Weed Press, 2 Jan..