Hydro-ecological relations in the Delta Waters

Eutrophication of marine coastal waters and estuaries is increasingly
regarded as a nuisance for the near future (Bosenberg, 1985).
Eutrophication is defined here as the pzocess of increasing
concentratian and load of inorganic nutrients, inducing changes in the
aquatic communities. In general terms the large European rivers provide
the main stLnuLus for nutrient enrichments in coastal waters. The main
rivers loading the surface waters af the South-West Netherlands are
Bhfne, Mense and Scheldt (Fig. l].
Figure 1 The Sduth-West Netherlands with the estuaries Oosterschelde
and Westerschelde and the brackish lagoons G~evelingenmeer
and Veerse Meer. The Bieshesch. Eollands Diep, Karingvliet
and Nieuwe Watemeg form the lower reaches of the Rhine and
M~use. The Westerschelde estuary is connected to the river
Scheldt. The Delta Works started in1960 ancl were finished 19
1987. The Volkerakdam was closed in1969 between Eollands
Diep-Haringvliet and Zoomeer. and blocked the main southern
exit of Rhine water.