This project aims to investigate the impact of the Sigma plan, dredging activities and port expansion on the environment in the zeeschelde. Eight work packages are involved, tackling the monitoring of fysical, chemical and biological parameters in the pelagic, intertidal and subtidal compartments, also including the lateral waste input of the zeeschelde and its major tributaries. Compilation of the data in a database is foreseen in such way that the construction of an ecological model can take place. Work package 1 (study of the water quality) contains a monthly monitoring campaign of the water quality of the zeeschelde and its tributaries, monitoring of 6 tidal cycles, and the coordination of all work packages.