Combined Sewer Overflow Management: Proof-of-Concept of a Screening Level Model for Regional Scale Appraisal of Measures

Abstract

Combined sewer overflows (CSO) represent a potentially important source of pollution in several river basins. Yet, the quantification of CSO loads is still problematic, and their management may be consequently hampered. In this contribution we present a proof of concept for a simplified, screening level model to quantify CSO loads, for regional scale applications. The model has two parameters, a runoff coefficient of the drainage catchment and the effective dilution ratio at which CSO begins. These two parameters enable appraising the potentials associated with reduction of runoff (e.g. urban greening) and retrofitting of the sewer network. We present and discuss a preliminary calculation for the functional urban areas (FUA) of the European Union, highlighting the possibility to use the model in the screening of management options.