Integrated urban catchment modelling for a sewer-treatment-river system

River water quality can be improved by optimising the urban wastewater system management through integrated operation of the transport and the treatment of these waters. Mathematical models are then useful tools to understand and explore the system in question. They allow to test various operating strategies and to see their effects on the long term. In this study of a river catchment in Luxembourg, the WEST\302\256 software is used as the modelling and simulation platform for the whole integrated system. It already contains standard models for WWTP and river processes. For surface runoff and sewer transport, the KOSIM hydrological model was implemented into the WEST\302\256 model-base. The implementation was thoroughly verified by comparing simulation results from both softwares. Also, backwater effects are taken into account through a conceptual model of backflows and results are compared to hydrodynamic results obtained with the InfoworksTM CS software. These are then used to calibrate the former.