Alpine Rhine

The Alpine Rhine Valley (German: Alpenrheintal) is a glacial alpine valley, formed by the Alpine Rhine (German: Alpenrhein [ˈalpm̩ʁaɪn] ^ⓘ), the part of the River Rhine between the confluence of the Anterior Rhine and Posterior Rhine at Reichenau and Lake Constance. It covers three countries, with sections of the river demarcating the borders between Austria and Switzerland and between Liechtenstein and Switzerland. The full length of the Alpine Rhine is 93.5 km.^[1]

From Reichenau, the Alpine Rhine flows east, passing Chur and turning north, before it turns north-east at Landquart, and then roughly north, east of Sargans. From here, the Alpine Rhine forms the border between the canton of St. Gallen of Switzerland on the left, west side, and the Principality of Liechtenstein on the east side. About 28 kilometres (17 mi) further down, the Rhine then meets the Austrian federal state Vorarlberg and finally flows into Lake Constance, south of Lindau (Germany), which is no longer part of the Rhine Valley. The Swiss-Austrian border follows the historical bed of the Rhine, but today the river follows an artificial canal within Austria for the final 5 kilometres (3.1 mi).^[2]

The Rhine Valley's upper third has the character of an Alpine valley, enclosing a bottom plain of about 1 to 4 kilometres (0.6 to 2.5 mi) across. Downstream of Vaduz, the valley widens considerably, developing into a broad plain, measuring some 10 kilometres (6.2 mi) across at its lower end along the southeastern shores of Lake Constance. From the point of the Rhine's emergence from Lake Constance, it is known as High Rhine.

Right tributaries of the Alpine Rhine are the Plessur in Chur, the Landquart in the town of the same name, the Ill and Frutz on the Upper Land of the Austrian plain near Feldkirch. The Alpine Rhine has no major left tributaries; creeks joining it from the left are the Oldisbach at Chur, Cosenz at Untervaz, Säge at Tardisbrücke, Tamina at Bad Ragaz, Tobelbach at Buchs, Simml at Gams. Though all left tributaries in the St. Gall Rhine Valley are collected by the Rheintaler Binnenkanal, which flows into Lake of Constance by Alter Rhein, and never meets the Alpine Rhine anymore.