Alceste
Vagabond
I would say a 'world wide' flood would have only been true once.
Considering there is about 1.4 billion cu km of water on the earth covering more than 70 percent of the globes surface and the average depth of the oceans is 4 km while the average elevation of the land is only 0.8 km above sea level, i think there is plenty of evidence that the entire earth has been flooded at least once.
No, that is not evidence that the world HAS BEEN flooded. That is evidence that the world COULD BE flooded, but only if it happened to be flat. Which it isn't, and never has been.
For that, we have mountains of evidence, literally and figuratively.