European watershed area of the Rhine, which empties into the North Sea via the Netherlands, and the Danube, which flows eastward emptying into the Black Sea. It enters Austria at Piz Buin in the Silvretta Alps running along the Arlberg massif and forming the border between the states of Tyrol and Vorarlberg. It reaches Bavaria, Germany via the crest of the Allgäu Alps and leaves the High Alps at the Adelegg range near Kempten. Within the Alpine foothills it runs north of the Schussen catchment area of Lake Constance towards the sources of the Brigach and Breg headwaters of the Danube in
Au, Vorarlberg Au, Vorarlberg Au is a town in the Bregenz Forest in the Austrian state of Vorarlberg, part of the district of Bregenz. The town belongs to the Bregenz Forest, more exactly to the "Hintere Bregenzerwald". Forty percent of its 45 km² area is covered with forest, 34.4% of the area is used as alpine pasture ("Almwirtschaft") and for other forms of alpine agriculture. The town itself is unlike others in the area, as it has no real centre. It consists of several districts, which are (in no particular order): Argenau, Wieden, Lugen, Lebernau, Rehmen, Schrecken, Kreuzgasse, Jaghausen, Am Stein, Argenstein,