Why are there so many flood legends?

Genesis

Chart adapted from B.C. Nelson, The Deluge Story in Stone, Appendix 11, Flood Traditions, Figure 38, Augsburg, Minneapolis, 1931.

When Noah and his family exited the ark and started life all over again, they were all very well informed about the flood and why it occurred.  They passed this information onto their children, and their children’s children, etc. and everyone was made aware of it.  About 100 years later, all of the post-flood people were living in the community surrounding the tower of Babel and they still knew about the flood.  After the great dispersal at Babel, the families separated and spread throughout the world, continuing with the flood and creation account but changing them up according to their own cultural and religious views.  Still, the flood legends we have today have many striking similarities.  The following website shows a chart revealing the similarities in flood legends and a narrative of some of the legends: http://www.nwcreation.net/noahlegends.html. This website shows many more flood narratives with references:http://www.talkorigins.org/faqs/flood-myths.html.  This final website offers additional information about flood legends and a lot of information about Noah’s Ark: http://worldwideflood.com/flood/legends/flood_legends.htm