The Lech is a river in western Austria and southern Germany.

From its source in Vorarlberg, the Lech flows northeast through the Tyrol and the town of Reutte, than northwards into Germany.

It is 264 kms long and flows from the right as a tributary of the Danube.

The German section of the Lech River is highly impacted by hydropower plants.

This is in complete contrast to the Austrian section which flows free with strong river dynamics for more than80 kms in length.

This is very rare in the alpine area, especially for a large river.

Through the area around Reutte, the Lech flows straight between embankments, 7.6 kms in length.

For these reasons, the section studied is from the source to upstream of Reutte (Höfen).  The section studied is 74 kms, 28% of the total length.