The complete utilization of the capacities of a complex sewage system, consisting of networks, storage and control assets, pressurized network and waste water treatment plants, especially for storm weather events is a central task to minimize the pollutant load discharged to receiving waters. With the objective of a minimization of water pollution load within the urban area of Berlin the project “Integrated Sewage Management” has been launched in 2000. The central points of this project are the application of integrated simulation tools for the examination of different management scenarios followed by the definition and installation of an integrated operation concept for the system. Special attention is turned to the combined sewage system where sewer overflows represent a potential risk for river pollution. Real time control of local regulators and thereby the activation of additional storage capacity within the network can lead to an optimization of the overall system. The paper is focusing on the methodology of model building to examine the sewage system and its operation management including geometric setup, measurement campaigns, calibration and validation. Moreover, the application of the model to evaluate the use of a mobile weir within the sewerage and its real time control is stated.