Cycle loop 13 watermills on the Grote Molenbeek, Maelbeek and Senne. Departure Weerde (90km)

This large cycle loop takes you along the 13 (remnants of) water mills along the Grote Molenbeek, Maalbeek and (lower) Senne.
The sources of the Grote Molenbeek and Maalbeek are located along a ridge between Relegem (source Maelbeek) and Kobbegem (source Grote Molenbeek) less than 900 meters apart (see POI https://www.routeyou.com/location/view/47532261/bronnengebied-grote-molenbeek-en-maalbeek.nl). That is precisely why they are cycled in loop form:
-->The Maelbeek flows into the Senne near the Burnt Bridge, which in turn flows higher up the Zennegat into the Dyle, then into the Rupel (after confluence with the Nete).
-->A little further upstream, between Ruisbroek and Wintam, the water of the Grote Molenbeek (which is called the Vliet there) is pumped into the Zeeschelde. Before the construction of this sea channel, it flowed into the slightly higher Rupel: From 1976 the Vliet was diked so that there are no tidal effects (and tidal floods) on this stream anymore). The Zeeschelde and the Rupel are connected by a (rarely used) lock in Klein Willebroek. Because the Grote Molenbeek no longer flows into the Rupel, not the Rupel but the Zeeschelde is included in the bicycle loop. This is done via a shortening along the Hazewinkel water sports track.
This gives you a pleasant cycle loop of 90 km along the Senne --> Hazewinkel lake --> (Brussels-Willebroek canal afterwards) Sea Canal --> (Vliet afterwards) Grote Molenbeek --> Maelbeek --> Zenne: A cycling loop along mainly natural watercourses that are all connected to each other. The lowest point of this loop (2 meters) is located on the Zeeschelde, the highest point (75 meters) on the narrow ridge between the sources of the two streams.

This cycle loop is special because all the remaining remains of watermills on the Grote Molenbeek, Maelbeek and lower Senne are cut: 13 in total. For most of them, the lockwork and water wheel are not visible from accessible terrain, the lockwork and water wheel have been partially or completely removed, or the lock walls and breakwater have also been removed. Of one watermill, only a tower ruin remains. Only on the Maelbeek in Grimbergen do you still have fully intact, working and freely accessible watermills (see http://www.mot.be/w/1/index.php/MuseumNl/Buildings).
According to the passage of the bicycle loop you have the following water mills:
On the Grote Molenbeek: Herbodinnenmolen, Diepensteynmolen, Marselaersmolen, Langeveldemolen, Binnenmolen, Ichtegemmolen, Neerkammolen.
On the Maalbeek: Sprietmolen, 's Gravenmolen, Liermolen, Tommenmolen, Oyenbrugmolen.
On the Senne: Weerdemolen.

You will find all the details about these mills or its remains at this location:
http://www.molenechos.org/kijk.php?provincie2=Vlaams-Brabant&sb=type&so=ASC&view_records=+Toon&AdvSearch=AdvSearch&db=bestaand

Take the Interactive map, zoom in on the loop between Malderen (top left Londerzeel) and Weerde (Zemst), and then click on the watermill POIs for the correct location, the streetscape and the current situation.

The most recent paved paths and landscaped cycle paths are used. And to stay close to the streams, they are crossed several times.
Other sights on the loop (see POIs): Chapel of Our Lady of the V-in-the-Hammeke, at high tide a railway line crossing next to the Senne in Hombeek, Zennegat, water sports track Hazewinkel, Klein Willebroek with locks on the Willebroeksevaart, pump house collection basin Grote Molenbeek, Castle of the Counts in Lippelo, beautifully renovated water castle Diepensteyn fed by the Grote Molenbeek, ridge with chapel between the two springs, a special wooden house with wooden entrance gate, etc. All this topped by many meanders and natural beauty.

The GPX of the bicycle loop starts at the church of Weerde (café 't Schoonzicht) and follows the route in a counter-hour direction (Zenne, north). After the crossing under the railway line in Hombeek, the drive is on the right bank of the Senne. As a result, the first 25km are cycled along the larger watercourses (wide towpaths), after which they cycle along the (Vliet, then) Grote Molenbeek and the Maalbeek. The first watermill can be reached after 40km, the last only at the end of the cycle loop on the Senne in Weerde.
You can of course start and stop the loop at any other point.

Naming (which is not strictly used here):
The Grote Molenbeek is given the following names from its source to its mouth in the Zeeschelde (source NGI): Grote Molenbeek --> Lippelose Beek (after confluence with a stream from the Lippelobos at the Kasteel Hof te Melis) on the border Malderen (Londerzeel)-Lippelo --> Vliet (after confluence with the Klaverbeek -formerly Vondelbeek-) between Lippelo and Oppuurs.
Other sources speak of the name change Grote Molenbeek-->Vliet after the confluence Grote Molenbeek and the (small) Molenbeek northeast of Puurs.
The Maelbeek is given the following names from its source to its mouth in the Senne: Landbeek --> Maalbeek (from the Maalbeekstraat at the town hall in Wemmel).