Modelling the sewer system of Brussels by means of SWMM and Cosimat

Scriptie/masterproef: Master's Thesis


The prediction of the quantity of combine sewer overflows in urban drainage systems has always been the primary purpose of sewer modelling. Nowadays, the stringent regulations been imposed on the quality of the receiving waters has led engineers and researchers to incorporate water quality aspects in most sewer modelling projects. For example in Brussels, despite huge investments made for the construction and maintenance of sewage collectors and waste water treatment plants, the quality of the receiving water is still very poor. Thus with the current situation, the objective of good ecological status imposed for surface water bodies by 2015 by the European Union Water Framework Directives may not be attained for river Zenne. In addition, the hydraulic behaviour of the combine sewer system on the left bank of this river is very complex as there are many complicated connections between the collectors, the siphon and other hydraulic elements present. This makes the exact quantification of combine sewer overflow volumes sent to the receiving water during overflow events very difficult. Since the quality of receiving waters depends on pollutant dynamics especially from sewer systems and this too depends on water quantity and fluxes (volumes, discharge and water levels) the proper modelling of water quality can therefore not be successful without proper modelling of water quantity.

Though many hydrodynamic models exist for the modelling of sewer systems, most of these models are commercial software which are not readily available to small consultancy firms and the university communities because of the high cost. Secondly, most of these hydrodynamic models are too detailed and have long computational times especially when long term simulations are involved. To overcome this dilemma in this thesis, a continuous simulation or conceptual model was developed using a dynamic programming software MATLAB/SIMULINK and was used in a complimentary way with SWMM model which is open free hydrodynamic software readily available online. Although MATLAB/SIMULINK is commercial software, it is not as expensive as the hydrodynamic software so it can easily be obtained by consultancy firms and universities without much investment.

The results show that the continuous simulation model developed produced comparable results with the hydrodynamic model especially if the main parameters which influence runoff quantity were well calibrated in both the detail and conceptual models.
Datum Prijs30 jun 2010
BegeleiderWilly Bauwens (Promotor)

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