Sumer is surounded on both sides with rivers. The rivers Euphrates and Tigris had, at one point, went into the Persian Gulf independantly, but gradually moved closer and entertered into the Persian Gulf in one river.umeria's climate was hot. Not only did the Sumerians deal with crazy rivers, but also had a harsh climate to deal with. It didn't rain often and when it did, it usually came as a storm from the Perisan Gulf.