Impact of Escherichia colifrom stormwater drainage on recreational water quality: an integrated monitoring and modelling of urban catchment, pipes and lake

In recent years, recreational waterbodies are increasingly favoured in urban areas. In spite of the growing concerns for maintaining the required bathing water quality, the impacts of stormwater drainage are still poorly controlled. In this context, this study originally develops an integrated urban catchment-pipes-lake monitoring and modelling approach to simulate the impacts of microbial quality from stormwater drainage on recreational water quality. The modelling system consists of three separated components: the urban catchment component, the 3D lake hydrodynamic component and the 3D lake water quality component. A series of processes are simulated in the model, such as rainfall-discharge, build-up, wash-off ofEscherichia coli(E. coli) on urban surfaces, sewer flows, hydrothermal dynamics of lake water and transport and mortality ofE. coliin the lake. This integrated model is tested for an urban catchment and its related recreational lake located in the Great Paris region. Continuous monitoring and samplings were performed at the stormwater drainage outlet and three different sites in the lake. Comparing the measured data with simulation results over 20 months, the modelling system can correctly represent theE. colidynamics in the stormwater sewer systems and in the lake. Although uncertainties related to parameter values, pollution sources andE. colimortality processes could be further discussed, the good performance of this modelling approach emphasizes a promising potential for urban bathing water quality management.