Modelling of Substance Flows in Urban Drainage Systems
Doctoral thesis, 2006

Stormwater is recognised as a large contributor of toxic substances to receiving waters. Different measures to manage stormwater quality have been proposed, including structural and non-structural best management practices (BMPs). Computer models have become useful tools for the analysis, evaluation and design of these BMPs. The main objective of this study was to develop a modelling framework that enables an analysis of the pollutant sources in urban drainage systems. In the modelling framework the sources of pollutants from different activities in the urban area were separated according to their origin, e.g. material corrosion, brake wear and tyre wear. The model was named SEWSYS® and was developed in MATLAB/Simulink. SEWSYS simulates substance flows in urban drainage systems. At present the model contains 20 different substances, including nutrients, heavy metals and organic pollutants. The model can simulate both stormwater and domestic wastewater flows, in either combined or separate sewer systems. In the stormwater quality module, the pollutants from sources such as atmospheric deposition, traffic and construction materials are generated and accumulated on impervious surfaces during dry weather until they are washed away during rainfall. Validation studies of the SEWSYS model were carried out using measurements of stormwater flow and quality. Calibration and validation were performed using a split-sample technique, i.e. with independent data sets for calibration and validation. The hydrological part of the model performed well in the validation but the quality part produced less reliable results. Uncertainty analysis of the stormwater module in SEWSYS was carried out for the model outputs runoff volume, pollutant concentrations (EMCs and SMC), and pollutant load of heavy metals for an uncalibrated and calibrated model. Uncertainty assessment methods included Monte Carlo simulations, multi-linear regression and a Markov-Chain Monte Carlo method for parameter calibration. The results of the uncertainty analysis showed that predictions made with an uncalibrated model were associated with a considerable amount of uncertainty. It was also shown that by means of calibration this uncertainty could be reduced to an acceptable level. The application of the SEWSYS model in different types of scenario studies has been an important part of the model development. The results from the application studies demonstrate that the model is a useful tool for simulating and evaluating pollutant source control measures.

urban stormwater

source control

modelling

diffuse pollution

BMPs

10.00 VK-salen, Sven Hultins gata 6, Chalmers
Opponent: Professor, David Butler, University of Exeter, Exeter, UK

Author

Stefan Ahlman

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Modelling substance flows in urban sewer systems using MATLAB/Simulink

Proceedings of the Ninth International Conference on: Urban Drainage ,September 8-13 2002, Portland, OR, USA/ Strecker, E. W., Huber, W. C.,;(2002)

Paper in proceeding

A modelling tool for simulation of sources and fluxes in wastewater systems: Focus on stormwater source control

Proceedings of the 10th International Conference on Urban Drainage, August 21-26 2005 / Eva Eriksson, Hülya Genc-Fuhrman, Jes Vollertsen, Anna Ledin, Thorkild Hvitved-Jacobsen, Peter Steen Mikkelsen,;(2005)

Paper in proceeding

Substance flow analysis of the stormwater system in Vasastaden, Göteborg

Proceedings of the Ninth International Conference on: Urban Drainage, September 8-13 2002, Portland, OR, USA / Strecker, E. W., Huber, W. C.,;(2002)

Paper in proceeding

Modelling non-structural Best Management Practices - focus on reductions in stormwater pollution

Water Science and Technology,;Vol. 52(2005)p. 9-16

Journal article

Methodology for systems analysis of sustainable wastewater management - assessment for an urban catchment in Vasastaden, Göteborg.

Proceedings of the 5th International Conference on Sustainable Techniques and Strategies in Urban Water Management (NOVATECH'2004). June 6-10 2004,;(2004)p. 457-464

Paper in proceeding

Subject Categories

Water Engineering

Other Environmental Engineering

Environmental Sciences

ISBN

91-7291-759-8

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 2441

10.00 VK-salen, Sven Hultins gata 6, Chalmers

Opponent: Professor, David Butler, University of Exeter, Exeter, UK

More information

Created

10/7/2017