ICPR – International Commission for the Protection of the Rhine

The R. Aar

The R. Aar (French: Aar, Arole; Luxemburgian: Aar; Dutch: Aare; Latin: Araris, Arola, Arula) has its sources in the two Swiss Aar Glaciers in the Grimsel region, it flows through Lake Brienz, Lake Thun, Lake Wohlen and Lake Biel and into the High Rhine near the German city of Waldshut and near the Swiss Koblenz. The Aar draining Switzerland is a tributary to the Rhine which has a higher flow of water than the latter so that, from a hydrological point of view, the Rhine is a tributary to R. Aar. The R. Aar is the longest river (288 km) having its watercourse only in Switzerland.
Just as the range of R. Aare, Lake Biel is navigable between Nidau and Solothurn. Along the range of the original river bed, the so-called Old R. Aar between Aarberg and Büren an der Aare is largely natural.