This infrared Landsat image makes it easy to see how deltas get their name - after the triangular shape of the capital Greek letter delta. When rivers meet the sea, the sediment they carry is deposited, forming mud flats, which over time generally extend further and further out to sea, becoming wider and wider - forming the classic triangular shape of the delta. In this picture the well-watered, vegetated delta (red) is clearly distinguished from the desert beyond. It is 770 kilometers from the apex of the delta to the coast.