I happened to come across this on Truthout .

I think this excerpt says it all:

"With his decision today, Judge Wanger has placed salmon survival back at the center of California's struggle to protect our natural heritage," said Sherwood. "There are several man-made factors that have contributed to the collapse of salmon runs. One factor is pumping too much of our water from the delta and exporting it south. This ruling makes it clear that there are biological limits to the amount of water we can export south."