The water level in Lake Shasta, California’s largest reservoir, had plunged to less than a third of normal by the end of last year. Then came the El Niño rainfall, which by April had tripled the volume of water in the lake. The story is similar in Trinity Lake, part of the same network of federal projects in the far northern portion of the state that regulate the flow of water to the Sacramento River on its journey south toward the Sacramento-San Joaquin River Delta and San Francisco Bay.
In the northern Sierra, water levels were also perilously low in the state’s second-largest reservoir, Lake Oroville on the Feather River. But snowmelt in that region has revived the lake and given some relief to the State Water Project, which also controls the water that eventually finds its way down the Sacramento River – and into the delta and the California Aqueduct, down the San Joaquin Valley, over the Tehachapi Mountains and into Southern California. If only it were that simple.