33 Rupel Valley

The Rupel is the 12 km long tributary of the Scheldt in which water from the Dijle, Zenne and Nete rivers converge. Today, the Rupel is a freshwater tidal river with strong tidal currents. On the left bank, the Brussels-Scheldt Sea Canal runs parallel to the Rupel from Klein Willebroek. The geosite includes the alluvial plain of the Rupel. Between Bornem and Willebroek, the alluvial plain is more or less bounded by the N16. The right bank of the Rupel valley is steep and is formed by the front of the Boom cuesta. 

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Origin of the landscape

During the Pleistocene, the precursors of today's rivers of the Scheldt Basin entered the Flemish Valley. At that time, the present Rupel Valley formed a branch of the Flemish Valley, within which flowed a braiding river that deposited sand. At the end of the last ice age, the Scheldt took its present course, and the Rupel ran with the Scheldt through the "breakthrough valley of Hoboken". During the Late Glacial, the braided river system changed into a wide meandering river. Along the meandering channels, riparian banks and serpentine ridges formed: elongated sandy heights parallel to the river. These channels and ridges are buried under younger deposits in the Rupel Valley, but are sometimes still recognizable in the micro-relief. When a forest vegetation developed, the filling of the meander channels started. A very last cold phase caused a barren landscape and the formation of river dunes. In the Rupel Valley, among other things, the elevations within the Blaasveldbroek are attributed to late glacial wind action.

Historic Rupel Valley

As farmers began to clear more and more forest, a new meandering system emerged, corresponding iglobally to the current course of the Rupel River. This river flooded more and more frequently, and from the Middle Ages on, there was also tidal action. Because of the growing pressure of the water and greater population pressure, the flood plain of the Rupel was diked in. Villages and fields were located on the sand ridges, while the polders were used as liquid pastures: by breaching dikes in winter, floods left a fertile layer of silt and increased hay yields. In the most peat-rich zones, peat was cut since the late Middle Ages, creating wet depressions. Today, these zones are recognized as wet, wooded lands, with ponds as fish ponds. The original Willebroek Canal was dug in the 16th century and connected Brussels to the Rupel via Klein-Willebroek. In the 20th century, the canal was modernized and connected to the Scheldt, keeping Brussels accessible to ocean-going vessels.