A major storm system is forecast to slam into California from Alaska and Canada starting Wednesday night, bringing soaking rain to the Bay Area on Thursday and dumping up to seven feet of new snow to the historically dry Sierra Nevada by Saturday. But as welcome as the snow is during a very dry winter so far, it won’t be enough to return the Sierra Nevada — the source of 30 percent of California’s water supply — back to its average for the year, experts said Tuesday.

The U.S. Supreme Court on Monday turned away a challenge led by states and environmental groups to an Environmental Protection Agency regulation that lets government agencies transfer water between different bodies, such as rivers and lakes, without needing to protect against pollution. The nine justices left in place a lower court ruling upholding the EPA’s “water transfers rule,” issued in 2008 by Republican former President George W. Bush’s administration, that exempted such transfers from a national water discharge program aimed at curbing pollution.

The U.S. Supreme Court on Monday turned away a challenge led by states and environmental groups to an Environmental Protection Agency regulation that lets government agencies transfer water between different bodies, such as rivers and lakes, without needing to protect against pollution. The nine justices left in place a lower court ruling upholding the EPA’s “water transfers rule,” issued in 2008 by Republican former President George W. Bush’s administration, that exempted such transfers from a national water discharge program aimed at curbing pollution.

Gov. Jerry Brown signed a bill into law Monday that will increase the frequency of inspections at the state’s most at-risk dams and require the Department of Water Resources to update dam safety protocols. Assemblyman James Gallagher, R-Yuba City, authored Assembly Bill 1270 following the Lake Oroville spillway crisis last February that saw more than 180,000 people evacuate.

After one year of torrential respite, drought may have returned to California, and with it, a renewal of the state’s perpetual conflict over water management. State and federal water systems have told farmers not to expect more than a fifth of their paper allocations, the state Water Resources Control Board is weighing a new regime of mandatory conservation, and supporters of more reservoirs are complaining about the glacial pace of spending $2.7 billion set aside in a water bond for more storage.