Amper

The Amper (German pronunciation: [ˈampɐ]), called the Ammer ([ˈamɐ]) upstream of the Ammersee, through which it runs, is the largest tributary of the Isar in southern Bavaria, Germany. It flows generally north-eastward, reaching the Isar in Moosburg, about 185 kilometres (115 mi) from its source in the Ammergau Alps, with a flow of 45 m3/s. Including its tributary, Linder, it is 209.5 km (130.2 mi) long. Major tributaries are the Glonn, which rises near Augsburg; the Würm, which is the outflow of Lake Starnberg; and the Maisach.

The term "Amper" can be derived from the Indo-European root * ombh-," which denotes water or a watercourse. The Celtic name "ambra" was adopted by the Romans and has been attested as genitive ambre and locative amber since the 3rd century. According to another interpretation, Amper is related to the Breton and therefore Celtic word ampart. Accordingly, the river name would stand for the terms skillful, agile and strong. In 1243 the Ammersee was first referred to as the Amirsee and it was not until the 14th century that a distinction was made between the Ammer as a tributary to the Ammersee and the Amper.

The Ammer, and thus also the Amper, drains part of the Ammergau Mountains to the northeast to the Isar and thus to the Danube. Over a distance of around 100 km, the Amper crosses four natural areas: the steep old and young moraines, the flat gravel plain and the Danube-Isar hill country. The Ammer/Amper river system overcomes a total of 430 metres (1, 410 ft) in altitude. The Ammer loses almost 200 meters in the 20-kilometer-long gorge south of Peißenberg.

The source area of the Ammer is located in the Ammergau Alps at the exit of the Graswang valley between Graswang and Ettal. Some of the water flows down from a raised bog, and some of the various spring pots in the valley floor are fed by the water of the Linder that emerges here on the border between Tyrol and Bavaria near the Ammersattel. The streams are fed by the Großer Ammerquellen, located on both sides of the river bed of the Linder, flow into the mostly dry bed of the Linder and, at some times of the year, together with the Li

Flows through: Germany.

River data from Wikidata (CC0); lengths normalised to a common unit.