As the water pulls back from long-time shorelines along California’s Salton Sea, officials are working to keep dust from the exposed lake bottom out of the air. Bruce Wilcox of the California Resources Agency looked out at what is now the new normal on the 35-mile-long lake’s southeastern shore. “Fifteen years ago there was water right where we’re standing and it’s just receded that much,” Wilcox said as he stood on a spur of land that used to be part of a boat launch.