Developing a simulation-optimisation model for quantitative and qualitative control of urban run-off using best management practices

The management of urban run-off is considered a success when the issues of flood and pollution are properly addressed. Flood can be controlled by reduction of peak flows and by treating polluted run-off. Best management practices (BMPs) are important tools for reducing pollutants and run-offs. Location of BMPs is an important factor in determining their optimum arrangement. In this paper, based on simulation-optimisation model, a methodology has been proposed to select proper BMPs with optimum arrangements. Quality and quantity of water flow in urban area were modelled, using Storm Water Management Model. Multi objective particle swarm optimisation was also used to reach the BMP layouts so that the peak flow and pollutant concentration can be effectively minimised. The proposed methodology was developed for district number 10 of Tehran municipality. The results showed that the proposed methodology could lead to an improvement in quantity and quality of run-off. For example, different combination of 32 BMPs led to a decrease in peak flow for 2, 5 and 10-year return periods as much as 10%, 21%, and 13%, respectively, while the combination of 45 BMPs decreased the total suspended solids mean concentration for 2, 5 and 10-year return periods as much as 50%, 57%, and 59%, respectively.