Modelling of sewer systems as a component of a global hydrological model

peer reviewedHydrology often takes an important place in the domain of hydraulic structures management, and is a key component of many hydraulic studies. Modelling the main hydrological processes requires a particular attention in order to deal with problems in an optimal way. Instrumented basins studies has pointed out the considerable impact of the sewer system on the hydrological outputs dynamics on small basins, even poorly urbanized. The current models often take into account the distributed impervious areas by adapting the corresponding surfaces runoff or infiltration coefficients. This approach, which is suited to produce correct runoff volumes, is however unable to represent the real flow outputs dynamics in which important variations can occur with a hourly time step. Modelling this flow component is essential to catch the rapidly-varying flow inputs generated by the runoff on drained impervious areas. An efficient modelling method has therefore been developed to include the sewer system in a global hydrological model (WOLF), using accurate landuse data in vector format and available data on the sewage system. These developments have been successfully tested on the Berwinne basin, Belgium