Flehbach

The stream is fed by several headwaters, most of which rise on the north-western slopes of the Tütberg within the municipal area of Bergisch Gladbach. The Kleine Wahlbach is considered the main channel, supplemented by the Wahlbach and Holzerbach tributaries; from the north, the Böttcherbach — rising near Moitzfeld — joins the flow. For roughly 2 km the Flehbach forms the boundary between Bergisch Gladbach and Cologne. In the Gladbach district of Lustheide it passes north of the Bethanien children's village. Through Cologne-Brück it runs alongside Flehbachstraße, the road named after it. In Cologne-Merheim it merges with the Bruchbach to form the Faulbach, which reaches the Rhine through a culvert.

The Flehbach once powered several water mills. Of the Flehbachmühle only the street name Flehbachmühlenweg in Lustheide survives; at the Erkermühle behind the Flehbachdamm, the mill pond has been preserved. In Mülheim the stream originally ran towards Düsseldorfer Straße and on to Wiesdorf. To combat flooding, it was redirected at the beginning of the 19th century through an artificially constructed channel leading directly into the Rhine.