Tigris and Euphrates are rivers of a capital importance for people living in the region, from the Sumerian six millenium and more ago, to modern-day Iraqis. If water management has always be vital -- up to the point of being in part at the origin of civilization and writing in the area--, it reaches now a critical point. Numerous reservoirs have been built upstream, in the four countries where these rivers flow (Turkey, Syria, Irak, and Iran), modifying substantially the hydology of the whole basin. Moreover, the marshes in the delta of the two rivers have been dryed up for the most part, then re-flooded for some, which lead to in-depth modification of the environment. Satellite observation of this hydrology is thus of special interest, especially since in situ measurements are scarce and difficult to retrieve.