The new water supply system
Pumping up the water, such is the system selected by Voies Navigables de France for the water supply of the canal. Explanations.
TheDeûle river waters
Since its opening to operation at the end of the 19th century, the Roubaix canal is supplied in water by the pumping station of the lifting plant located in the commune of Lille. The water required is pumped in the lower Deûle river and brought through a feeder to the pumping station and pumped over 7 km through underground pipelines up to the summit pound upstream the Masure lock, the highest lock along with the Union lock.
A century-old ackward system
But today the whole system has to be revised: the pipeworks have become scaled, the lead is corroded, the low streamflow regime of the Deûle river limits the volume of transferable water and the poor to very poor quality of the Deûle river waters would spoil the good quality of the Roubaix canal waters.
Now, water is recycled at each lock
On the ground of financial, technical and environmental criteria, the pumping station and the old conducts are now abandonned for the benefit of small pumping stations fitting each lock. This allows to save the water of the Deûle river during the low flow season and at the same time to preserve the good quality of the canal waters.
However, the mere operation of the locks and the weather conditions produce definitive losses that need to be compensated.
A further supply thanks to the Grimonpont 
plant
A lagooning area will be created nearby the wastewater treatment Grimonpont plant. It will be used as a storage facility for the waters downstream the plant where they undergo a second biological treatment of 30 days before being discharged in a buffer basin. This last basin will feed the canal during the night and will serve as a dam in case of accidental pollution.
Treated by the wastewater plant, retreated by Voies Navigables de France, stored and analysed before being reinjected in the pound, one could not wish any better situation for the quality of the canal waters.
The site of the wastewater treatment plant in 2002
