Article révisé par les pairs
Résumé : The long time data series provided by the Flowbru regional hydrometric network ( represents a new opportunity to gain knowledge on the hydrographical systemin Brussels. With a combination of data mining analysis, data consolidation, models and in-depthdata interpretation, new insights on sewer system performance are obtained. First, the problemof the infiltration of parasitic clear water into the sewer system is addressed. A new methodologyis developed to compute the daily volumes of clear water infiltrated in the entire zone treated bythe Brussels-North Wastewater Treatment Plant (WWTP). We show the strong seasonal variationof infiltration and how this pattern can be identified in limnimetric time series to highlightsewers which are subject to infiltration. Secondly, the sewer sediment accumulation in theBrussels Right main collector – the largest sewer in the Brussels Region – is studied. Theaccumulation dynamics are discussed, and a comparison between the present situation and thatof the 1980s shows the massive increase in sediment accumulation in recent decades. Thepotential causes and consequences of this accumulation are discussed briefly.