The word got out and the environmental lobby was quick to pounce: After years of silence on the issue, Gov. Gavin Newsom’s administration was reviving a controversial plan to burrow a tunnel beneath the Sacramento-San Joaquin Delta, the fragile hub of California’s water-delivery system. Environmentalists said the tunnel would wreck the Delta, not fix it. Ailing fish populations would be driven further to extinction. The reworking of the Delta’s plumbing would leave Delta farmers with water too salty for raising grapes, tomatoes and other crops, they said.