These cut-off arms have become valuable recreational areas and a nature reserve.

In 1900, the short-cut at Fussach was completed, linking the natural course of the Rhine just upstream of Höchst and St. Margrethen directly to a new outflow into Lake Constance.

The old river course downstream of this point, via Rheineck to Altenrhein on the shore of Lake Constance, became known as the Alter Rhein and continues to form the border between Austria and Switzerland.

In 1906, the Rheintaler Binnenkanal ("Rhine Valley Inland Canal") was dug, connecting Sennwald to St. Margrethen.

In 1923, another short-cut was completed at Diepoldsau, creating another dead branch, also named Alter Rhein.