The Obama administration underscored the threat of climate change to Western water supplies Tuesday, releasing a report that projects less snowpack in the mountains and reduced flows in major rivers — all of which spells a much drier future for places such as California.

The report estimates that diminished runoff from the Sierra Nevada will prompt an average 9 percent drop in state reservoir levels by the end of the century and a 3 percent dip in deliveries to cities and farms from the major water projects.

 

A potentially major new fight has erupted over Gov. Jerry Brown’s plan to build two huge tunnels beneath the Sacramento-San Joaquin Delta, and this time the protests are coming from a group of farmers that wants the tunnels built.

The San Luis & Delta-Mendota Water Authority, a powerful San Joaquin Valley farm water agency, demanded Monday that two members of the State Water Resources Control Board be disqualified from a crucial hearing on the tunnels scheduled for early May.