A simple model of flow-rate attenuation in sewer systems. Application to urban stormwater source control

•A top-down approach is proposed to model “soft” city-scale stormwater solutions.•An empirical model of flow-rate attenuation in the sewer system is developed.•The attenuation model is used to test the effectiveness of source control regulations.•Which regulation is the most effective depends on the position in the catchment.•Simple models can improve stormwater management strategies at the city-scale. In urban stormwater management, “soft” solutions are being widely applied, including stormwater source control. However, no specific resource-effective model is available to assess their effects at the city-scale. As a consequence, source control regulations are often based on simplistic hydrologic assumptions. In this paper, we apply a top-down modeling approach to this problem, and we develop a simple model of flow-rate attenuation in the sewer system, using a numerical empirical approach. Then, we apply the model to source control regulations, assessing which type of regulation is more effective depending on relative positions in a catchment. We show that a model requiring only two types of information about a catchment (concentration time and pluviometry) can provide relevant information on source control effectiveness. This information could be helpful, for example, to define a stormwater zoning.