Brazilian World Cup host city Manaus has declared a state of emergency as the waters of an Amazon River tributary rise, though officials say the river is not expected to flood. Manaus city government spokeswoman Jacira Oliveira said the 180-day state of emergency that began Tuesday is only a preventive measure to assure quick access to emergency resources if the Rio Negro (Black River) unexpectedly spills into the city. Even if there is flooding, Oliveira said it would not damage the Arena Amazonia stadium that will host four World Cup matches.