Both the European directives and the Dutch-Flemish Long Term Vision (LTV) oblige to monitor the abiotic and biotic parameters to evaluate the development of the Scheldt estuarine system. This will allow the analysis of the evolution in regard to the defined goals of the directives. Before 2007, Flanders and the Netherlands had their own monitoring programmes. Within the scope of the LTV it was decided to integrate both programmes: both the parameters to be measured as the measurement and processing techniques are being synchronized. The final "MONEOS" monitoring programme considers six topics: hydrodynamics, morphodynamics, physico-chemical parameters, diversity of habitats, diversity of species and ecological functioning.Flanders Hydraulics is responsible for monitoring a large part of both hydrodynamic and physico-chemic parameters. At more than 20 locations within the estuary water levels are continuously measured. Flow velocities, temperature, conductivity and turbidity (optical backscatter method) are measured at five locations within the estuary, while, among other parameters, discharges and sediment fluxes are measured at the up-estuarine boundaries. Beside these continuous measurements, flow velocities (ADP) and suspended sediment concentration (ADP-backscatter) are measured at several cross sections in the estuary.