These verese describe a river that splits into four rivers parting with the single river that going through Eden. The first two of these rivers are called the Pison and Gihon and despite the decryptions of their locations they have no match to any post Flood rivers. The third is called the Hiddekel, which is another name for the Tigris. The forth is called Euphrates, but no location is given. This is likely a description is looking upstream with a river that separated into four.