Hydro-ecological relations in the Delta Waters

marsh development in the east of the Western Scheldt.
Just as in the case of morphologi~al developments, natural
developxcents often take place on a time scale which far exceeds ehe
term of the average government. This is particularly important in the
case of natural developments, because O~WOIIS of the desired course
of such developments are subject to change. Bowever, this concerns not
sa ioch the ecelogical conditions, which have been dealt with earlier,
hnt ware the management and policy choices which affeet natural
developaent. This applies particularly to former intertidal areas.
To date natural devel6pmenta in rhe Delta have sometimes faced us with
unexpected situations. Although naru mre is knm of the directions in
which nacure can develop, it is important to be aware that the future
may still hold surprises in this respect. Since hug-term developments
are involved, it is important to guard against phasing the successive
stages too rigidly and against trying to steer them too qnicklr in a
certain direction.
Water meaagemeqt rewbs a key confro1 element iu natural development,
especially tn areas along the banks. It is clveial to maintain not
only the quihity, but particularly the level of the vatar. nspits
this fact, in almost no Delta area wat~rlavelmanageaeut is geared to
natural development. This is due KO orher secid interests having been
taken WO considmation. In the damstream freshwater areas of the
Delta, the potential for natural develapment would be optimally
furthered by waterlevel mmagement, which reflected the nacural rise
and fall of waterlevels in downstream areas. In the case of the salt
lakes of the Dslta this is leas clear-out. The best approach is
probably to maintain a standard level, with brief periods of flooding
in winter. Howeven, in the event of a review of or change in
waterlevel-ent great weight shanld 4e attached so the qatural
development factor.