Hase

The Hase is a 169.7-kilometre-long river of Lower Saxony, Germany. It is a right tributary of the Ems, but part of its flow goes to the Else, that is part of the Weser basin. Its source is in the Teutoburg Forest, south-east of Osnabrück, on the north slope of the 307-metre-high Hankenüll hill.

After about 15 kilometres, near Gesmold and about 6 kilometres west of Melle, the Hase encounters an anomaly of terrain and bifurcates such that each branch flows in a different drainage system:

one third of its waters flow along the south side of the Wiehengebirge hills eastward from Gesmold into the Else, which begins there, and flows into the Werre at Kirchlengern. The Werre is a tributary of the Weser.

Source: Wikipedia