A good understanding of hydraulics is a necessary condition for understanding biogeochemical cycles and morphology of estuaries. It is a true scientific challenge to quantify the alteration in loads of suspended matter in the Scheldt estuary that takes place when the trench is further deepened or when the proportions of discharge coming from the upper Scheldt and Rupel are altered. Currently the effects of these changes on the morphology of intertidal areas cannot be predicted.

A specific factor of uncertainty is flocculation: coagulation of fine sediment and organic material. The reason for their existence remains unclear. The dynamics of suspended matter is a key element because it is determining for the light climate in the water. Since in the Scheldt estuary light penetration is limiting for the development of fytoplankton, there is a link with the study of primary production.

The foregoing fits in the framework of a broader research that tempts to unravel the carbon cycle according to origin. The experimental quantification of denitrification in the pelagial and the study of the interaction between primary production, flocculation, nitrogen fluxes will provide a refined understanding of nitrogen removal. Through these studies our knowledge on the biogeochemistry of the estuary and the possibilities to model important cycles will increase.

The pelagic as well as the bentic biodiversity of the estuary will be studied. The morphological characterisation of the river bottom has to be extended. Regarding to the plankton, the role of the zooplankton as a link between fytoplankton and the higher trophical levels as well as the relation between the presence of plankton and the loads of sediment and the waterquality is still unclear. Macrozoobenthos has mainly been studied in the brackish part and the saltwater part of the estuary. The macrozoobenthos community in the freshwater part mainly consists of Oligochaetes. A shift in the composition of the macrozoobenthos and its biogeochemical role can be expected in this part of the estuary when the water quality ameliorates. The study of the role of intertidal areas and controlled inundation areas in the recovery of fish populations implicates a study of feeding, migration and nursery possibilities.

The pressure on above-mentioned ecological functioning by pollutants is another very important research domain. The research mainly investigates the influence of changes in environment on the bio availability of the micro contaminants and the effects on individual, population and community level.

Specific interactions between controlled inundation areas with reduced tidal movement and the river trench will be studied in an integrated manner in a pilot project. In this pilot project such an area (Lippenbroek) is intended to be followed up by various partners.

Another interesting objective is to compare the knowledge that is being developed for the Scheldt estuary with the knowledge for the Seine estuary. Both estuaries suffer analogue problems, for example a progressively penetration of the tide, harbour expansion and dredging activities with a severe impact on the morphodynamics of the system. Large scaled interdisciplinary research has lead in both estuaries to a thorough understanding of the system (e.g. the OMES project for the Scheldt, the Aval project for the Seine). Generally the Seine can be considered as a pelagic system. Only in the mouth part of the river intertidal areas are present. In the system of the Scheldt however, there is a lot more exchange between the intertidal and the pelagic. Despite the hydrological differences a comparison between both systems can clarify the role of intertidal areas.