Q: I would like to know in detail about the great Hindu flood account.
A: The myth of the flood in Hinduism goes as follows:

“When Manu was washing his hands one morning, a small fish came into his hands along with the water. The fish begged protection from Many saying, “Rear me, I will save you.” The reason stated was that the small fish was liable to be devoured by the larger ones, and it required protection till it grew up. It asked to be kept in a jar, and later on, when it outgrew that, in a pond, and finally in the sea. Many acted as asked.
The fish forewarned Manuy of a coming flood and advised him to prepare a ship and enter into it when the flood came. The flood began to rise at the appointed hour, and Manu entered the ship. The fish then swam up to him and he tied the rope of the ship to its horn, and thus passed swiftly to the far northern mountain. There Manu was directed to ascend the mountain after fastening the ship to a tree and to disembark only after the water had subsided.
So he gradually descended and so the slope of the northern mountain is called Manoravataranam, or Manu’s descent. The waters swept away all the three heavens, and Manu alone was saved.” (adapted from the Satapatha Brahamana as translated by Pusalkar in HCIP, vol 1m ‘The Vedic Age,’ p. 271f.)

Some say this flood was at 3102 B.C. when the beginning of the Kali Yuga began. This is a possible date for this event.
The Sumerians also have a flood account, the Gilgemesh Epic. And the Bible has an account as well in Genesis, the first book of the Bible. These accounts each have very interesting parallels in them with one another. Many have tried to discover which one is the original and have assumed that it is merely a mythological account. Another interesting possibility is that something like this actually happened and therefore each of the civilizations (distant from one another) have a similar account. John Keay notes in his recently published work on India that they have found archaeological evidence of a flood in the Sumerian city of Shuruppak which coincides with the possible date of 3102 B.C. I find it fascinating that some many cultures have this kind of an account. I conclude that some kind of devastating flood did occur in and about this time.
Wyatt Robertson