Sulm (Austrian river)

The Sulm is a river of 83 km length in Southern Styria (Austria) which originates at the eastern slopes of the Koralpe (a north-south running mountain range in the Southeastern Alps which separates Styria from Carinthia), and flows eastwards towards the Mur through the districts of Deutschlandsberg and Leibnitz. The Sulm valley runs from the Western Styrian hill ranges to the Eastern Styrian hills and lowlands.

The main tributaries of the Sulm are the Schwarze Sulm ("Black Sulm"; with Schwanberg as the central market town) and the Weiße Sulm ("White Sulm"; with Wies) which merge near the village of Prarath, upstream of Gleinstätten. It is there where the actual Sulm valley is considered to begin. Further downstream, near Großklein and Fresing, the Sulm proceeds to receive the Saggau river, and - close to Leibnitz - the Laßnitz river, immediately before the Sulm makes a sharp turn to the Southeast and flows almost parallel to the Mur river before joining it.

The Sulm runs on top of a thick bed of its own massive quaternary deposits, and therefore the valley bed is now quite flat although (as can be deduced from the remaining terraces on its rims) it must have been steeper initially. The river therefore breached its banks easily, and used to cause frequent major flooding, until it was regulated from the 1960s onward.

A unique geographic feature in the Sulm valley is the Sausal mountain range which has its own mild microclimate, supporting a significant fraction of Styria's wine-growing economy.

The Sulm valley has yielded archeological finds from the neolithic period onward, illustrating that it has served as an east-west traverse for thousands of years. In the Iron Age, during part of the Hallstatt Culture period, a settlement on the Burgstallkogel between Gleinstätten and Großklein had considerable regional importance. The associated necropolis, part of which can still be seen, is one of the largest and best-preserved in Central Europe although much has been plundered from the late 19th century onward.

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Wikipedia