This paper presents the modification and the application of the conceptual wash-off model initially proposed by the SWMM on five separate urban catchments with very different characteristics and during a lot of rainfall events. To allow measurements on real sites to be considered, this model was incorporated in an overall model including simulation build-up, sediment transport in collector as well as runoff and hydraulics. This modified model has been calibrated, validated, transposed and completed with sensitivity analysis of parameters and initial conditions. The proposed model gives some improvement to the results of the initial model: an adaptation to a large range of rainfalls, the correct reproduction of the peak values and satisfying reproduction of the beginning and the end of the TSS pollutograph.

This paper presents the application of the conceptual total load model of Velikanov through a description of the solids behaviour, its calibration using numerical optimisation and the results on real sites. In order to take into account the full scale measurements, the Velikanov's model has been included in a global model for solid production and transport in sewer system which is divided into four modules: hydrologic, hydraulic (Muskingum model), pollution (build-up, wash off and total load) and calibration functions. The calibration of Velikanov parameters has been made using a procedure of numerical optimisation based on the Powell method. The solids behaviour is characterised by settling velocity (ωs) and density (s) which varies between fine particles (ωs=5.4m/h and s=2.00) essentially transported in suspension and coarse particles (ωs=45m/h and s=2.65). The results of the calibration phase on three real French sites which presented dry weather sediments and the validation phase can be considered of good quality. Simultaneous measurements of rainfall, hydraulic and TSS concentration allowed a large range of calibration and validation. This model provides a satisfying fitting of the real TSS pollutographs and this, considering the global form, maximal value and the temporal position.

This paper presents the conceptual model for solid production and transfer in combined or separate sewerage systems called HORUS. The objective of this model is, taking into account the characteristics of the catchment and the structure of the sewerage system, to reproduce the hydrographs, Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) concentration generated by any rainfall. HORUS consists of main connected modules and the retained algorithms have been chosen after using a special Testing Bench of Pollution Modelling Algorithm in Urban Sewer System. The main modules are: a hydrological module (linear reservoir and runoff losses), a hydraulic module (described by the Muskingum model), a module for solids production and transport (build-up and washoff of catchment and solid transport in sewer) and a module for numerical optimisation. The improvement of the HORUS model is shown by a comparison between simulation results versus the initials algorithms. Simultaneous measurements of rainfall, hydraulic, TSS and COD concentrations on nine very different catchments and about one hundred rainfall events allowed a large range of validation which can be considered of good quality. HORUS provides a satisfying fitting of the real TSS and COD pollutographs (flow and concentration) and this, considering the global form, maximal values and the temporal position.