Modélisation du transport solide en réseau d'assainissement unitaire : le modèle HYPOCRAS

Solid transport modelling in combined sewer systems The HYPOCRAS model

CIRSEE - Lyonnaise des Eaux-Dumez 38 rue du Président Wilson, 78230 Le Pecq

Abstract

A global and conceptual model for solid production and transfer in combined sewer systems has been established. This model, named HYPOCRAS, is valid for small urban catchments of less than 100 ha. Its storm weather part simulates the sediment build-up over the catchment, the washoff by rainfall, the solid transfer along the sewer pipes, the erosion and sedimentation of deposits. Two classes of particles are distinguished : the fine ones (d₅₀ = 40 µm) which are transported in suspension and the coarse ones (d₅₀ = 400 µm) which constitute the deposits and which are transported in bed load or in suspension depending on the hydraulic conditions. The model has been calibrated and verified for three different catchments, with satisfactory results.