California’s ambitious $15 billion plan to tunnel below the largest freshwater estuary on the West Coast in hopes of fixing its water woes will “minimize” effects on endangered salmon, state officials said Tuesday — though environmentalists doubt it. The California Department of Water Resources said the controversial project will give officials more flexibility in monitoring and controlling water temperatures in the Sacramento-San Joaquin River Delta, and protect juvenile Chinook salmon from river pumping stations. The department released its latest biological assessment of the project, which must be approved by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service.