Hydro-ecological relations in the Delta Waters

- category Grevelingen: basins with closure dams at hn, sides,
disconnected from tidal influences and without any [Qrevelingenmeer.
Veerse Meer) ar with very limited fluvial influences (Volkerak -
Zoommeer) ;
- Oostecschelde: a basin with a half open dam at the seaward side and
closure dams at the lahdward side, with reduced tide and
disconnected from fluvial inflnences;
- Westerschelde: an estuary 13 the true sense, with both tidal and
fluvial imflueuces.
Construction of rhe seaward closure dams has disrupted the former
morphirlogical uncity of estuary and ebb tidal delta into two distinct
subsysrems: a basin and a (relict) ebb tidal delta.
In general, tidal currents and -ranges have been reduced and fluvial
influencee limited, while wave impacts have remained unchanged.
3.2 Category Haringvliet
Within the Haringvliet hasin fluvial currents and waves are the only
geomorphelogicalIy active forces left after fiiaishfng of the
Harfn~vliet nam in 1971. The tidal Emge has been diminished from ca.
2 m to a negligible 0.2-0.35 m. The ahst total disconnection from
tiaal iniluences has kmcked large scale sedimentation in tba channels
(Pi&. 6) and erosion of shoals and mudflafs; the shorefaces of several
Figure 6 Channel sedimentation in the Haringvliet-Hollandsch Riep
basin over the period 1970-1983 (Van Otterloo, et ill. 1987)