To Kai,
The Sumerian version of Gilgamesh legend does mention Ziusudra and the Flood in the
Death of Gilgames and in independent
Flood Story (which is also known as the
Eridu Genesis in some circles). These are Sumerian literature were written somewhere between 2300-2000 BC, and are based on older oral traditions. The Sumerian language and literature died out, but their stories were adopted and adapted in the Semitic Akkadian language, and later Babylonian and Assyrian languages.
A more complete Creation/Flood story is available in Akkadian text, called
Atrahasis.
You must understand clay tablets are often fragmented, so don't expect any complete translation. This is most unfortunate.
I can suggest two books, which offered better readability than the links I had provided above.
The Epic of Gilgamesh: A New Translation
translated by Andrew George
Penguin Classics, 1999
Myths from Mesopotamia
translated by Stephanie Dalley
Oxford World's Classics, Revised Edition 2000
The 2nd Book has Akkadian flood story, called Atrahasis. While the 1st book have Sumerian version of Gilgamesh legend.