Corky Herkenhoff, who’s been farming at San Acacia for half a century, told me he can tell where the runoff is coming from by the smell. San Acacia sits just below the Rio Puerco and Rio Salado, two generally dry tributaries that have been pumping water into the Rio Grande over the last week. Herkenhoff said he can tell the difference. “You can tell when the Rio Puerco comes in, and you can tell when the Rio Salado comes in,” he said.