Was the biblical flood account borrowed from older accounts ? 

No. 

Article - Flood Legends from Around the World - Answers In Genesis 

Video - Why Moses' Version of the Flood is the Most Reliable Ancient Account - J. Warner Wallace

Video - Noah's Flood and The Epic of Gilgamesh - Hank Hanegraaff 

Audio - Worldwide flood legends - Answers In Genesis 

Video - The Bible and Plagiarism: Repurposing the Stories of Old - Cynthia Chapman