This report discusses possible scenarios for the future management of the landfill site ‘Laag-Vlaanderen’ in the municipality Wervik, which is used for disposal of polluted sediments dredged in the Leie. No new sediments were deposited since 2005 and the site is rapidly being colonized by plants. These recent changes in plant cover and hydrology could stimulate the leaching of heavy metals or their uptake in plants. There exists a clear need to decide between possible final management scenarios for the site.
Measurement of heavy metals and organic pollutants in the soil show that at least the upper 30cm of soil are only lightly polluted. Although deeper layers do contain heavy metals and organic pollutants, the concentrations are below the values of previous measurements in the older dredged sediment landfills along the Leie. Three management scenarios for Laag-
Vlaanderen are discussed, two of which propose afforestation of the site. Introducing forest is an interesting option since suitable tree species could control the heavy metal fluxes throughout the ecosystem. Moreover, afforestation is a useful tool for landscape planning and forest expansion. An afforestation plan is proposed with tree species that are adapted to the soil type and characterised by low heavy metal uptake rates. Finally, a list of instructions for preparing the site and planting the trees is proposed in order to limit mortality and maximise growth.