To save SF Bay and its dying Delta, state aims to replumb California

The report’s findings were unequivocal: Given the current pace of water diversions, the San Francisco Bay and the Delta network of rivers and marshes are ecological goners, with many of its native fish species now experiencing a “sixth extinction,” environmental science’s most-dire definition of ecosystem collapse. Once a vast, soaked marsh and channel fed by the gushing San Joaquin and Sacramento rivers, the Delta has diminished dramatically over the previous century as those rivers and their mountain tributaries have been diverted to irrigate farms and Bay Area urbanity. With winnowing supplies of chinook salmon available for food, Orcas off the coast are starving. So, too, are seals and fish-eating birds. And the Gulf of the Farallones, a national marine sanctuary, is suffering from a lack of freshwater fed by the bay. Those grim conclusions in this fall’s report by scientists at the Bay Institute, an environmental group focused on the bay’s ecosystem, would normally have set off alarm bells — except that those warnings have been sounding for decades. That’s about as long as state agencies have been in the planning process to replumb the region that supplies close to half of California’s water and supports world-leading agricultural production, fisheries and tourism. The state’s goal: recalibrate the water flows that have drained vital rivers down to as low as 10 percent of their natural levels — just one-fifth of the 60 percent flow scientists say is necessary to preserve the ecosystem.