A method taking uncertainties into account to evalu ate the rate overflow in CSO using water-depth measurements

This article focuses on a general method to assess the overflow rate in sewage networks and especially in CSOs, where one of these conditions i s fulfilled: the geometry is complex, a bijective relationship between the upstream and the downstream flow is not available, the downstream hydraulic conditions are complex or difficult to define and then to model. This computational fluid dynamics based methodology, using measurements of the water depth in the overflow device, has already been described and validated in previous articles. Therefore, this study focuses on the treatment and integration of the uncertainties in the determination of the most suitable depth-overflow relationship. The three uncertainties taken into account are linked to the numerical model, the boundary conditi ons and the water level sensors. This approach is illustrated through an example of the “ Milan” CSO of Mulhouse city, FRANCE.