The Dender (French: Dendre) is a river in Belgium in the basin of the Scheldt. It flows through the provinces of Hainaut, East Flanders and Flemish Brabant over a length of 65 km. The Dender rises in Ath (height approx. 40m) at the confluence of the Eastern Dender (source on the border between Masnuy-Saint-Jean and Masnuy-Saint-Pierre) and the Western or Kleine Dender (source at Barry) and flows into Dendermonde on the right bank of the Scheldt.
Between Dendermonde and Aalst, the Dender can be navigated by ships with a cargo of up to 600 tons. Upstream from Aalst, the Dender is navigable for ships up to 300 tons, but the river is currently mainly used for recreation. In the summer months, the fully navigable part can be covered on board a few inland vessels. From Aat, you can reach Tournai and Mons via the Blaton-Aat Canal and the Nimy-Blaton-Péronnes Canal.
The river crosses the following cities: Geraardsbergen, Ninove, Aalst and Dendermonde located in the Dender region. The Dender is not tidal water; it is cut off from the Scheldt by a lock. The pollution of the Dender has been tackled fairly well in recent years and due to the economic evolution many small industries have disappeared along its banks (connection between northern France and the Scheldt).
The Dender's pelvis includes the following major side streams:
the Mark with a basin of 180 km² near Geraardsbergen;
the Molenbeek, which flows into the Dender on the left bank in Zandbergen, a sub-municipality of Geraardsbergen, and has a catchment area of 55 km²;
the Bellebeek or Alfene with a catchment area of 100 km² which, on the border of Affligem and Liedekerke, flows on the right bank;
the Molenbeek-Ter Erpenbeek, which flows into the Dender on the left bank in Hofstade, a sub-municipality of Aalst.
In addition to its value for tourism, there may also be an economic future for the Dender. There is increasing talk about a possible shift from road transport to transport by rail and water. Government proposals on this subject were discussed in news broadcasts of July 30, 2003.