Défis futurs pour les systèmes de drainage urbain concernant les émissions de débordements d'égouts unitaires
Future challenges for urban drainage systems regarding combined sewer overflow emissions
- Auteurs
- Martina Hauser, Yannick Back, Alrun Jasper-Tönnies, Manfred Kleidorfer
- Résumé court
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- Summary
- Urban drainage systems must adapt to future challenges driven by climate change and urban growth. Increasing intensity and frequency of extreme precipitation events and prolonged dry periods in combination with surface sealing-driven urbanisation affect surface runoff, combined sewer overflow (CSO) frequencies, volumes and emission concentrations as well as flood hazard. While extreme precipitation events are more relevant for flood hazards, smaller precipitation events are more relevant for emission concentrations in CSOs. In contrast to the Austrian directive for the design of CSOs, defining a minimum efficiency based on rainfall characteristics (r720,1), the revised urban wastewater treatment directive proposed by the European Commission demands a stormwater overflow of less than 1% of the annual collected urban wastewater load. This study analysis the drainage system of the city of Innsbruck, located in the western Austrian Alps. The CSO emissions are predicted using a conceptual model and a simulation period of more than 10 years. Based on the model, the two different directives are compared under different future climate scenarios, including changes in precipitation patterns and number of decoupled areas. Results will develop a better understanding of changes in emission concentration and the efficiency of the system under future climate change scenarios and with regard to the different directives.
- Mots-clés
- Impacts du changement climatique, Extrêmes climatiques, Émissions des débordements des égouts unitaires, Directive de l'Union européenne, Ruissellement des eaux pluviales