Amid a drought year and declining fish populations, California water officials are again sketching lines across the Sacramento-San Joaquin Delta, hoping to move fresh water to people and farms without wiping out endangered species.
California voters pilloried the last attempt in 1982. It was a relatively simple trench that would have carried a portion of the Sacramento River around the Delta to state and federal export pumps, and then to points south.
A generation ago, critics feared the canal was a south state water grab, though scientists now seem to agree that separating exported fresh water from the Delta's environment may be a good idea.
The new canal on the scene aims for something similar, but without actually taking water out of the Delta.
Instead of a self-contained canal that skirts the Delta, the new proposal diverts a portion of Sacramento River flows into a series of armored levees that wind through the center of the Delta. Most proposals would turn the south fork of the Mokelumne River and Middle River into this proposed canal.
Called "through-Delta conveyance," it also includes gates across some side channels to keep out salt water during high tides. Bolstered levees would be built to withstand earthquakes, floods and a predicted sea-level rise caused by global warming.
Scientists estimate it is likely that multiple Delta islands will flood by 2050 in a natural disaster. This would contaminate fresh water, now drawn from the Delta at large, which serves more than 23 million people and millions of acres of farmland.
That's why Gov. Arnold Schwarzenegger kept some form of Delta canal in his latest water bond proposal, announced Tuesday. But his new plan contains no money for the project. Instead, it directs the Department of Water Resources to work with any other agency that wants to build and pay for a canal.
The plan provides $1.9 billion for Delta ecosystem restoration programs, but only if there's progress on a canal in some form, said Mark Cowin, DWR deputy director. Without conveyance, he said, that $1.9 billion disappears.
"We need a comprehensive approach that addresses both ecosystem improvements and conveyance of water through the Delta. This provides a package to move both of those issues forward together," Cowin said.