Tigris in the north of iraq , it is a great river in Iraq , it com from the mountains of Turkey in the north. the Tigris flow through Turky and Iraq, many tributaries flow into the Tigris inside Iraq. some of these tributaries are big , such as the upper Zab and the lower Zab . the Tigris meet the Euphrates south of Qurna and form one river . this is called the shatt-el-arab, which flows into the arab Gulf south of Fao.