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The Flehbach LEAP

Welcome to the Flehbach LEAP

The Flehbach LEAP is a Learning, Exploring and Activity Path (LEAP) in Cologne. Here you have the opportunity to learn more about your environment, especially about the aquatic environment of the Flehbach. Whether as a citizen scientist, hiker, visitor or student, there is much to discover, to learn and to explore.

The Flehbach is one of several streams on the right bank of the Rhine river in Cologne. It has a length of about 17 km and arises from the confluence of the Holzerbachs and the Großer Wahlbachs, which have their sources in the area of the Tütberg in the Königsforst (146 m above sea level) in Bergisch Gladbach. It flows through the Königsforst and collects on its way the water of other streams. These include the Böttchererbach, the Small Wahlbach, the Wasserbach and finally the Selbach. After leaving the Königsforst the Flehbach flows through the Cologne districts of Brück and Merheim. From the confluence with the Bruchbach it is called "Faulbach". The Faulbach is channeled from the street "Stegwiese" in Cologne-Buchheim and runs underneath the Wichheimer road, Bergisch Gladbacher road, Holweider road, Keup road and finally draines at the Düsseldorfer Straße in Cologne-Mülheim into the Rhine. The Flehbach / Faulbach overcomes from the source to the mouth a height difference of 98 m. Its catchment area is around 77 km ² in size.

The creeks on the right bank of the Rhine in the Cologne urban area originate from the transition zone between the Cologne Bight area and the Bergisches Land. The Cologne Bight is a relatively flat geological area, which extends like a bight into the mountaineous area of the Bergische Land and the EIfel. The Bergisches Land is part of the Rhenish Slate Mountains and consists of geologically very old, mostly water-impermeable solid rocks, while the Cologne Bight Area is made up of permeable sands and gravels. Therefore, and because there are significantly higher rainfall in the Bergisches Land in the annual average, many rivers and streams arise in the Bergisches Land, some of which seep into the Cologne Bight area.

The traces of the last ice age in this landscape can be clearly seen from the terraced landscape structure, the Rhine terraces. Floodplains, are located directly adjacent to the creeks and the Rhine. The floodplains are flooded at high tide, as far as no dam prevents. The flooding of the floodplain is not only important for flood control but also has important ecological functions. The floodplain is usually connected to a first terrace. A edge of mostly 1-2 m height indicates the slope to the first terrace. This slope  can be best seen in undeveloped terrain. This lower terrace is called the Niederterrasse. It marks the floodplain of the Rhine during the last ice age. This area is no longer flooded and therefore has long been used for roads (e.g., the street Mauspfad uses this dry ground).

In the course of history, the stream beds have been changed, obstructed and in part completely cannelzied. The Flehbach / Faulbach shows the full diversity of a natural stream in the area of the Königsforst to the completely modified river by piping and by the drainage in the urban sewer system.

Discover the stations of Flehbach LEAP. There are interesting things to detect not only on the topic of water, but also to the vegetation, the soil, the animals in the forest and the clouds. We invite you to discover the environment around the Flehbach with the help of the explanatory plates provided at various locations of the Flehbach LEAP and by using smartphone Apps!

The texts of the Flehbach LEAP were written by Prof. Dr. Karl Schneider and Dr. Verena Dlugoß based on the sources given here.