Page "Sacramento River" Paragraph 17

Starting in the 20th century, dam construction blocked off hundreds of miles of salmon-spawning streams, such as the upper Feather and American Rivers, and the entirety of the Pit and upper Sacramento rivers.

Pollution from farms and urban areas took a heavy toll on the river's environment, and heavy irrigation withdrawals sometimes resulted in massive fish kills.

Since 1960, when the big pumps at the head of the California Aqueduct in the Delta began their operation, the outflow of fresh water into the Pacific has been reduced to a trickle leaving the fish confused as to where to go, resulting in many generations dying off because they have not been able to find their way upstream.

In 2004, only 200, 000 fish were reported to return to the Sacramento ; in 2008, a disastrous low of 39, 000.