Hydro-ecological relations in the Delta Waters

develwpment of lasting and valuable systemnr. This should wt be
interpreted as a licence to compartmentalize estuaries and to create
polders in coastal areas. V we have learned one thing, it is that
estuarine systems are precious and irreplaceable, both in ad
ecological and aa ecoMmic sense. Estuaries are by nature highly
productive and dyllamlr systems. Adequate protection of these area*
against pollution, over-exploitation and other detrimental
inflames can provide a lasting guarantee for such assets.
The c~npartmenralization of the Delta had taught us that this is no
matter of course in the case of the thus created waters. The
developments, which this process triggered off, require close
supervision if these newly-formed waters are to achieve their full
potential, and these new Delta waters do indeea have the potential to
develop into valuable systems.
The nacural relacions in che Delta have been upset. However, it has
been replaced by new relations. In some cases this has happned on a
fairly lbited scale, whereas in others an entirely new natural basis
has been created. Natural relsti~ns are no lwger taken for granted.
Instead it must be taken for granted that an attempt will he made
wherever possible to manage the Delta in its present form as a single
coherent whole. The lessons which have been learned up tb now. and
which have been dealt with extensively in previous chapters, can help
ta guide this process.
The build-up of silt and pollutants are processes with which the
Netherlands, as a delta-country, is eminently familiar. This problem
has also affeceed the Delta of the South-West Nerherlands, and the
following lessons have been learned:
- Upstream pollution results in the build-up of pollueants in
d6wnstrsam sedimentatibn areas with serious detrimental effeets cm
ecological development and economic potential (e.g. pollution of
eels). This process is being reinforced by dsuuning up the
downstream areas at one side. Therefore dadng up cannot be seen