The Danube's vast drainage of some 315,000 square miles (817,000 square km) includes a variety of natural conditions .... squar river

The Danube's vast drainage of some 315,000 square miles (817,000 square km) includes a variety of natural conditions that affect the origins and the regimes of its watercourses. It covers about 18,000 square miles (47,000 square km) at the Inn confluence, 81,000 square miles (210,000 square km) after joining with the Drava, and 228,000 square miles (590,000 square km) below the confluences of its most affluent tributaries, the Sava and the Tisza. More than half of the entire Danube basin is drained by its right-bank tributaries, which collect their waters from the Alps and other mountain areas and contribute up to two-thirds of the total river runoff or outfall. To the south of the river course stretches the large Bavarian Plateau, covered with thick layers of river deposits from the numerous Alpine tributaries. Other major tributaries in the upper Danube course include the Iller, Lech, Isar, Traun, Enns, and Morava rivers. In its middle course the Danube looks more like a f! latland river, with low banks and a bed that reaches a width of more than one mile. A principal result of this deposition has been the formation of two islands, one on the Slovak side of the river and the other on the Hungarian side, which combined have an area of about 730 square miles (1,900 square km) that support some 190,000 inhabitants in more than 100 settlements. In this long stretch the river takes on the waters of its major tributariesthe Drava, the Tisza, and the Savawhich create substantial changes in the river's regime. The river valley looks most imposing there, and the river's depth and current velocity fluctuate widely. Beyond the Iron Gate the lower Danube flows across a wide plain; the river becomes shallower and broader, and its current slows down. The Danube covers an area of some 1,660 square miles (4,300 square km) and is a comparatively young formation. squar river