River catchment sanitation by sediment management - A Flemish case study

In the framework of an integral water management-policy, the sanitation of the water courses in the Flemish region is developped through small-scale projects to study local river catchments in a global environmental way. Indeed, the complex processes need a multidisciplinary approach to guarantee a successful implementation of water resources strategies. In the Zwalm-catchment, a small river catchment situated in the interfluvium between Upper-Scheldt and Dender in the South-Western part of Flanders, this basic philosophy is explored in a pilot-project. Local morphological circumstances requires a study with focus on the sediment transport and its management.Indeed, a combination of sand-mud river beds, severe land erosion and discrete flood flows direct the sanitation program at a sediment management project. Sedimentation and transport of fine materials, as a favourite adhesive medium for pollutants, induce a general pollution of both water and river bed in the downstream reaches. In order to reduce the high treatment costs of the dredged (mud) material, some specific arrangements are necessary to realize an economical sanitation procedure.