Reduce Delta water use or build canal, report says

California must either dramatically reduce its use of Delta water or build something akin to the Peripheral Canal, the highly controversial proposal rejected 25 years ago to allow parts of the Bay Area, San Joaquin Valley and Southern California to tap directly into the Sacramento River, according to a major new study released Wednesday.

The report also says that decades of policies designed to keep the Delta's water fresh are wrongheaded, in effect putting the drinking water supply of much of California in direct conflict with the needs of a severely weakened ecosystem in which populations of several fish species are extremely low.

Salinity in the Delta historically fluctuated between salty and fresh, depending on the season and the amount of rain and snow that fell and flowed into tributaries leading to the Delta. Improving the ecosystem requires bringing back more variable salt levels, which is impossible now because it would ruin drinking water supplies for 23 million people and irrigation water for millions of acres of farmland, the study said.

By building a Peripheral Canal or something like it, water for most of the state would be taken out of the Sacramento River instead of the southern Delta, allowing managers to let the Delta become saltier at times.

Doing so could benefit native fish, including Delta smelt, and create less hospitable conditions for invading species, said Peter Moyle, a University of California, Davis fish biologist and one of six authors of the study.

from the Oakland Tribune