Fahrräder : Stoßbelastungen der Vorderradachse

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Charlemagne's Summit Canal: An Early Medieval Hydro-Engineering Project for Passing the Central European Watershed

<div><p>The Central European Watershed divides the Rhine-Main catchment and the Danube catchment. In the Early Medieval period, when ships were important means of transportation, Charlemagne decided to link both catchments by the construction of a canal connecting the Schwabian Rezat and the Altmühl rivers. The artificial waterway would provide a continuous inland navigation route from the North Sea to the Black Sea. The shortcut is known as Fossa Carolina and represents one of the most important Early Medieval engineering achievements in Europe. Despite the important geostrategic relevance of the construction it is not clarified whether the canal was actually used as a navigation waterway. We present new geophysical data and <i>in situ</i> findings from the trench fills that prove for the first time a total length of the constructed Carolingian canal of at least 2300 metres. We have evidence for a conceptual width of the artificial water course between 5 and 6 metres and a water depth of at least 60 to 80 cm. This allows a crossing way passage of Carolingian cargo scows with a payload of several tons. There is strong evidence for clayey to silty layers in the trench fills which reveal suspension load limited stillwater deposition and, therefore, the evidence of former Carolingian and post-Carolingian ponds. These findings are strongly supported by numerous sapropel layers within the trench fills. Our results presented in this study indicate an extraordinarily advanced construction level of the known course of the canal. Here, the excavated levels of Carolingian trench bottoms were generally sufficient for the efficient construction of stepped ponds and prove a final concept for a summit canal. We have evidence for the artificial Carolingian dislocation of the watershed and assume a sophisticated Early Medieval hydrological engineering concept for supplying the summit of the canal with adequate water.</p></div

Synthetic longitudinal profile of the Fossa Carolina from Graben to Rezat River.

<p>a) The red line shows the Pre-Carolingian surface and watershed, the red dot indicates the summit the natural watershed. b) The short horizontal bars feature the Carolingian levels of excavation deduced from the drilling stratigraphies, and the blue dot indicates the artificial summit of the Carolingian trench bottom. c) The solid black line represents the level of the recent trench surface following the course of the canal.</p

Cross section of the West-East Section at core O position.

<p>Cross section of the West-East Section at core O position.</p

Stratigraphical documentation of the KG 256 cross section within the North-Eastern Section.

<p>The cross section shows the in situ layers of the Rezat fen in the East and the trench structure in the West. For the first time there is in situ evidence for a Carolingian trench in the North-Eastern Section. The trench bottom is shown by horizontal bars.</p

Digital elevation model of the Central Section including detailed drilling positions.

<p>Raw data source: LIDAR data are cordially provided by Bavarian Land Surveying Office for illustrative purposes.</p

Types of sediment texture in the Central Section and the West-East Section.

<p>a) fluvial type and b) ponding type.</p

The local topographical setting of the Fossa Carolina.

<p>The canal is located across a valley watershed between the Altmühl River (Danube catchment) and the Swabian Rezat River (Rhine-Main catchment) within the Treuchtlingen valley junction at the piedmont of the Franconian Jura escarpment. Data source: Open access SRTM data (3 arc-second, 90 m raster, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108194#pone.0108194-Greenbelt1" target="_blank">[72]</a>) and OpenStreetMap <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108194#pone.0108194-OpenStreetMap1" target="_blank">[73]</a>.</p