The legend of Noah's flood was developed out of flood legends current in the first millenium b.c, and was probably a conflation of different legends. Some scholars think that the source of the legend may be the flooding of the Black Sea in 5,600, but others have speculated that the legend might have been based on floodings in Mesopotamia.
The origins of the legend
The Bible story There was never a time when the whole earth was flooded, but there have been spectacular floods at various places, many of which have become conflated into one big one. The biblical story was pieced together out of legends just after a 1000 b.c and give a religious slant with a moral message. However, legends are often based on real events, so we need to ascertain what they were. The Black Sea flooding This theory is still disputed by archaeologists, but what is known is that Ballard, who took a submarine down into the Black Sea, found evidence of structures made by humans at about 100 metres down. He also spotted what appeared to be an ancient shoreline at a similar depth, indicating that the water level had risen and flooded human habitations. The indication is that there was serious and permanent coastal flooding. Problems The difficulty is knowing how serious it was. Some scholars think that, as sea levels rose after the ice age, waters from the Mediterranean broke through in the Bosporus and poured into the Black Sea through a waterfall, which would have dwarfed the Niagara Falls, but others think that there might already have been a lake there. Nevertheless, humans fled the region, and the event lingered in the memory as the Great Flood.
Some of the Bible story has affinities with Mesopotamian legends about a great flood. In 1929, Leonard Wooley, working at Ur in southern Mesopotamia, now southern Iraq, unearthed a thick layer of black mud, and having dug through it, found human artefacts. Ur was then on the coast, though now as the coastline has silted up, it is seventy miles from the sea. The evidence is of a serious coastal flooding in about 3500 b.c. However, this was very localised and there were other smaller floods at various times. It is likely that this historical fact became merged with other flood tales. Mount Ararat Tales of the the remains of Noah's Ark having been found on Mount Ararat in Turkey have never been substantiated. There seems to be a natural ship-shaped depression in the ground high on the mountain, but there is nothing to suggest that this is other than a natural phenomenon.