Breakthrough block of the Molenbeek

At the end of Isabellastraat (connection with IJsbergstraat), the valley of the Molenbeek becomes much narrower. Here you have a breakthrough valley. Officially, a breakthrough valley is a valley of a river that runs through a mountain range or hill ridge, perpendicular or at a large angle to the longitudinal direction of the mountain range. Here everything is much less pronounced, but you can still see characteristics returning. Breakthrough valleys have the property of being narrow, and that is true here as well. Originally, the hill ridge along IJsbergstraat connected with that of the hill ridge along Doylijkstraat. But that ridge has been broken through.

If you head more towards Sint-Gertrudis-Pede, upstream, you will see that the stream valley of the Molenbeek very much widens with a broad alluvial flat valley bottom along the southern side that is dozens of meters wide. That broad and flat valley bottom extends further up to the famous watermill in Sint-Getrudis-Pede.

This place, between the confluence of the Laarbeek and the Molenbeek, and the intersection of Doylijkstraat-IJsbergstraat-Roomstraat was also a possibility to build a watermill and create reservoirs of water with dams in this narrow valley. But that was built 600m further upstream in Sint-Gertrudis-Pede where a similar geomorphological situation exists.

Pascal Brackman