Valley widening

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A valley widening is geomorphologically understood , in a vague and varying definition, a valley section between two narrow passages or breakthroughs . Due to the softer rock compared to the breakthroughs, the river was able to create clearance through erosion . Valley widening can also arise or be reinforced by karst dynamic processes.

Valley widening has been a frequent component of natural area names since the 1950s , although the criteria according to which a natural area is named as valley widening vary significantly from region to region. Many valley widenings - especially those that are almost half as wide as they are long - are also known as basins . The reverse is also possible (see picture of the Sobernheim valley widening below).

"Valley widening" as part of the name

Relief of the Middle Rhine (detail): From south to north the Rhine runs through the Lahnsteiner Pforte with the confluence of the Lahn from the east, the Neuwied Rhine valley widening with the Moselle from the southwest and the Wied from the north , the (natural) Andernacher gate (the actual Andernacher gate , a short widening and the Hammersteiner Pforte), the Linz-Hönninger valley widening consisting of two partial widenings with the mouth of the Ahr from the west in the second and the Honnef valley widening , which merges to the north (outside the section) into the Cologne Bay

Since the work on the handbook of the natural spatial structure of Germany and refinements 1: 200,000 , "valley widening" has been a frequent component of natural area names. Since the editors of the individual natural space sheets had a free hand in choosing names, there are both areas where such names occur frequently and areas where they are avoided.

The relief image on the right shows a total of three widening of the valley by name of the Rhine (definition of the southernmost and naming of the middle on sheet Koblenz 1971, delimitation of the middle and definition of the northernmost on sheet Cologne 1978). The Neuwied Rhine valley widening as its southernmost is better known as the Neuwied Basin . While the valley widening is only understood to mean the completely flat area (the entire landscape including the hill country is called the Middle Rhine Basin ), the Sobernheim valley widening (relief image below; definition on sheet Mainz 1964) is understood to mean the basin-like hilly landscape, which, especially to the north, extends far beyond the Valley floor.

The following lists are listed in sections according to main unit groups ; First the Rhine is followed upstream from north to south, then its tributaries on the left bank of the Rhine, the one on the right bank of the Rhine and finally the Weser. The lists are arranged in sections alphabetically by river. To make it easy to find, there is always a link to a location in the natural area, usually the one of the namesake. After the name of the natural area, the code number and finally the name of the three-digit main unit follow in brackets.

Middle Rhine area

See Middle Rhine area .

Saar-Nahe-Bergland and Moselle valley

The middle Nahe with the narrow Obersteiner Naheengtal in the southwest, the already much wider Kirner Nahe valley northeast of it and finally the Sobernheim valley widening to the east-southeast . The latter includes a basin landscape 14 km long in the direction of the river and up to 6 km wide perpendicular to it.

Since there is only one valley widening out of the main unit group Moselle Valley and this is located on the Saar, it is listed together with the valley widening of the Saar-Nahe mountainous region , which only has one valley widening in the catchment area (or on ) the Nahe.

Main Franconian plates

See Mainfränkische Platten .

Black Forest

See the natural structure of the Black Forest ; the rivers are ordered from north to south.

Lower Saxony highlands

See Lower Saxony mountainous region .

Individual evidence

  1. ^ Herbert Louis : Textbook of general geography . Part: Vol. 1., General Geomorphology , p. 176a. 3rd edition, Berlin 1968; DNB 457386592
  2. ↑ Georg Schulz: Lexicon for determining the terrain forms in maps , p. 282; University Press of the TU Berlin 1989; ISBN 978-3798312838 ( digitized version , Google Books )
  3. ↑ Heinrich Müller-Miny, Martin Bürgener: Geographical land survey: The natural spatial units on sheet 138 Koblenz. Federal Institute for Regional Studies, Bad Godesberg 1971. →  Online map (PDF; 5.7 MB)
  4. ^ Ewald Glässer: Geographical land survey: The natural space units on sheet 122/123 Cologne / Aachen. Federal Institute for Regional Studies, Bad Godesberg 1978. →  Online map (PDF; 8.7 MB)
  5. ↑ Harald Uhlig : Geographical land survey: The natural space units on sheet 150 Mainz. Federal Institute for Regional Studies, Bad Godesberg 1964. →  Online map (PDF; 4.7 MB)