Sediment transport model in sewer networks - a new utilisation of the Velikanov model

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.