Illach

The Illach is a nearly 23 km long tributary of the Lech in Upper Bavaria with a catchment area of about 40 km².
It is fed by a series of spring creeks on the northern slope of the Hochwildfeuer mountain in the Trauchberg massif, the most significant of which springs at about 1,260 m altitude and is called Markbächl. In its upper course, the Illach flows mainly northward through the area of the municipalities of Wildsteig and Rottenbuch, turning westward near the Rottenbuch district of Rudersau, and finally reaching the Lech just below the Lech dam stage 3 at Urspring. Its discharge behavior fluctuates between a flow of 1 m³/s and 60 m³/s. These fluctuations are related to pre-Alpine precipitation.

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