Basin-wide integrated modelling via OpenMI considering multiple urban catchments F. Reußner, J. Alex, M. Bach, M. Schu ¨ tze and D. Muschalla ABSTRACT F. Reußner M. Bach D. Muschalla Section of Engineering Hydrology and Water Management, Institute of Hydraulic and Water Resource, Technische Universita ¨ t Darmstadt, Petersenstraße 13, D-64287 Darmstadt, Germany E-mail: reussner@ihwb.tu-darmstadt.de; bach@ihwb.tu-darmstadt.de J. Alex M. Schu ¨ tze ifak e. V. Magdeburg, Werner-Heisenberg-Strasse 1, D-39106 Magdeburg, Germany E-mail: jens.alex@ifak.eu; manfred.schuetze@ifak.eu D. Muschalla modelEAU, De ´ partement de ge ´ nie civil, Pavillon Adrien-Pouliot, Universite ´ Laval, 1065, avenue de la Me ´ decine, Que ´ bec G1V 0A6, QC, Canada E-mail: dirk.muschalla@gci.ulaval.ca Integrated modelling is currently receiving a lot of attention in the field of urban hydrology. This paper describes a method for carrying out integrated modelling of sewer systems and rivers, where the constituent models are linked to each other using the European OpenMI interface. This has the advantage that, once the necessary software extensions have been carried out, the data sets describing the subsystems can be used as they are without any need for adaptation. Key words | integrated modeling, OpenMI, urban wastewater system, water framework directive INTRODUCTION Traditionally, the major elements of an urban wastewater system (UWS), e.g. the sewer system, wastewater treatment plants (WWTPs), and receiving water bodies, are con- sidered as separate entities, and emission-based criteria form the basis for legislation and standards in many countries. The European Water Framework Directive (EC 2000) demands ecological, water quality driven approaches for river basin management, which will also have impli- cations for UWS (Walsh 2000). Due to continuous improvements in sewage treatment and the resulting increasing efficiency of WWTPs, many of today’s problems regarding water quality are caused by combined sewer overflows (CSOs) and storm water discharges. Traditional planning approaches, however, are no longer sufficient in this context. The minimisation of CSO spill volumes, frequencies, and loads for instance, are inadequate objectives, since they do not guarantee the achievement of the desired ecological quality of the receiving water body (Rauch & Harremoe ¨ s 1999; Lau et al. 2002), and an optimum management of the individual components of an UWS does not necessarily yield optimum perfor- mance of the entire system. Therefore, an integrated approach accounting for various sources of impacts on receiving water bodies has been advocated (Rauch & Harremoe ¨ s 1996). This paper describes the development of a simulation- based analysis and planning methodology for the German Federal State of Hesse for the identification of critical impacts due to CSOs and WWTP effluents. An important part of this methodology is an OpenMI based integrated doi: 10.2166/wst.2009.471 1241 Q IWA Publishing 2009 Water Science & Technology—WST | 60.5 | 2009 Downloaded from https://iwaponline.com/wst/article-pdf/60/5/1241/448441/1241.pdf by guest on 17 June 2020