The River Scheldt currently has a macrotidal estuary with a tidal reach of 160km. It covers a complete salinity gradient with a polyhaline, mesohaline and oligohaline zone and a fresh water part with long and short retention time of chloride. The estuary and its tidal tributaries Durme and Rupel have been heavily influenced by anthropogenic pressures such as land reclamation, harbour expansion, dredging activities, embankments and urbanisation. A good understanding of the impact of human interventions on the ecological functioning of the estuarine ecosystem is required. Based on this knowledge appropriate compensation or mitigation measures can be taken in response or anticipation to future negative effects of anthropogenic changes and relative sea level rise. In this study, all available data on tidal regime (1850-2000), bathymetric charts (1930, 1950, 1960, 1970, 1980, 1990, 2000) historical maps from the beginning of the 19th century onwards and aerial photographs from 1944 onwards were compiled and analysed for the Zeeschelde (Belgian part of the Scheldt estuary) and the tidal tributary river sections.The report deals with three main issues:(1) Ecological changes during the past century are analysed using a hierarchical ecotope approach.The evolution of the acreage of the distinguished physiotopes (physically characterised units) andecotopes such as shallow waters, tidal mudflats and marshes are analysed for each salinity zone or river section;(2) Changes in hydrodynamic and morphological parameters are analysed over the past century;(3) An overview of anthropogenic interventions and natural changes with potential effects onhabitat acreage and quality in the Zeeschelde and its tidal tributaries in the past two centuries. Thenature of the interventions is very diverse: reclamations, diking, land use change, infrastructureworks, dredging activities, canalisations, discharge manipulations and changes in river dynamics.Changes in tidal regimeBecause tidal regime is a key factor in an estuarine ecosystem, we ...