Modeling of iE. coli/i distribution for hazard assessment of bathing waters affected by combined sewer overflows

摘要

Combined sewer overflows (CSOs) affect bathing waterquality of receiving water bodies by bacterial pollution. The aim of thisstudy is to assess the health hazard of bathing waters affected by CSOs.This is useful for bathing water managers, for risk assessment purposes, andfor further impact and economic assessments. Pollutant hazard wasevaluated based on two novel indicators proposed in this study: the meanduration of insufficient bathing water quality (1) over a period of time(i.e., several years) and (2) after single CSO/rain events. In particular, anovel correlation between the duration of seawater pollution and the eventrainfall volume was developed. Pollutant hazard was assessed through a coupled urban drainage and seawater quality model that wasdeveloped, calibrated and validated based on local observations.Furthermore, hazard assessment was based on a novel statistical analysis ofcontinuous simulations over a 9-year period using the coupled model.Finally, a validation of the estimated hazard is also shown. The healthhazard was evaluated for the case study of Badalona (Spain) even though themethodology presented can be considered generally applicable to other urbanareas and related receiving bathing water bodies. The case study presentedis part of the EU-funded H2020 project BINGO (Bringing INnovation to OnGOingwater management – a better future under climate change).