Hydro-ecological relations in the Delta Waters
Hydro-ecological relations in the Delta Waters Hydro-ecological relations in the Delta Waters
Lt has been estimated that the sedimentation process Of the channels in order to establish a new equilibrium will involve some 500 millions lU3 of sediment over the next cedtnries. The total erosive effect over the next 30 years h& been elculated as a lass of shoal- and mu-t area amounting to circa l500 hectares i.e. 10 - 15% of the present total area (Rohsiek, et al. 1987). The total area of salt marshes very drastically has been reduced after caepletion of the Delta Project. Since 1987 only 24% of the originally total area of salt marshes in the kingvliet, Grevelingen. Volkerak and Oaaterschelfle is rewining in the Oosterschdde. It ia estimated that these saltslarshes are subject to sn increased rate of erosion. VegetatioO mid erosion resistance most probably have been weakened considerably as a result of a proloagued period of extrae tidal reductiod duritrg, the final constmctiDn phase of the Oostersahelde works. The Oosterechalde's ebb tidal delta has shown a continuing exwinsion over the period 1960 - 1983 as a result of the tikl voluae inerease and resulting basin erosion over this period. Van den Berg (1986) has ralculated a net sedimentation over these years of ca. 38 millions m'. This is i n aceordance with the expeered trend as stated in Section 2.2. The decrease of tidal volume after 1987 indicates an opposite gesmorphrtls~ical trend for the future. It is expacted that the deltafront will erode. the tidal channels will silt up and longshore sandbars will develop a< the edges hheiek end Nulder, 1989). No geoolorphological data are available yet to confirm this. Tidal end gwmorphological changes af the Wastersehelde basin ove-r the last 30 years are mainly due to large $tale dredging. Because of it's importance for shippfng traffic to the harbours of Antwerp, no closure daar has been defined for the Westewchelde. Wifhin the fra81evork of the Delta Projeet security against flooding around this estuary h- been odtained by strengthening of the dykes. The intensified shipping
~raffic, however, has irldueed a rfiatiner increase of large sale dredging activitias fnm about 1970 (Pig. 10). Figure 10 Impact of dredging and dumping in the WeBtefsGhelde 0% the development e-f sam& shod8 {Ww. 198'3) The drtifieiar deepening of the chhmels hy dredging llae oontributall ta an -larrmse of tidal frolume in rhe basin of 3 - 73 over the period 1970 - 1985 (Van den Be~g. 19871. %keoreticdly (Eis. 4A) these hydraulic and gwmcrpholo@cal chaqes should invoke an ecqanaion of the sandy shoals, Ohserufftkms over the period 1955 - 1987 largely coDfim this (Pia. 187. Future developnte of the tide1 landscape will d+psnd mainly on the actual policy Bf dredging and dwfs&. Westee&elde4s ebb ti4a1 delta skeuld haye shown aa expanding cen&er,cy over the pert98 I970 - 1917 in reapwse ts an ine.reashg ci.dal valume km&??a 3eietio-a 2.2). A moz~hoiwgt~al dweveSopuient in this sense. bowever, has bees trmd co &seme over ~h*. past yeam. tidal laadseirpe eeema W have been aetemhed to if greets* -&end by dredging. . sad bovipUg aartiv&ties 6n titre eb21 tidal delta ir~lf. Deepeatris 6f shfpp&q C&nnB&e and expaturion of Ze@br.aggc ~. harbour roffiated the &zedgin$ md dwzng &f sbae 4a0. 0;l1IImi mj sededbent otr the WasZeec&elae ebb tidal de&a between 197B arrd 1984 [Van den Ems, 1987.). mhss ettriicieal pi~l .26-bntf1~* to dhtarafnO futuik a&ve1iip*es.
- Page 43 and 44: , 0.66 m 0,s - 0.02 1989 I 0.86 - 0
- Page 45 and 46: Table 3 Eutrophication of the Volke
- Page 47 and 48: Laks Volkarek ---- Lake Zoom 0.40 0
- Page 49 and 50: 4 WAGBEET MEdSIIRaS TO PEEVBT OR LT
- Page 51 and 52: Table 5 gives estimtes of the phosp
- Page 53 and 54: In principle, two states of equilib
- Page 55 and 56: Zooplankton (Alma affinis) Pike (Es
- Page 58 and 59: EUTROPHICATION OF ESTUAAIES AND BRA
- Page 60 and 61: The average discharge of Xhine and
- Page 62 and 63: and only l-2% cows frm the aive Sch
- Page 64 and 65: highest trophic potential: nutrient
- Page 66 and 67: period 1980-19$3 in an increase of
- Page 68 and 69: model calculations reveal that a ni
- Page 70 and 71: Table 3 PreUmInary carbon budget of
- Page 72 and 73: Water life of Lake Grevelingen
- Page 74 and 75: macrophytes livkg on or rooting in
- Page 76 and 77: less predictable for water managers
- Page 78 and 79: ILWNEWIJK, A.. KEIP, C., 1988. De v
- Page 80 and 81: XBE CHANGING TmAL LAMXiCAPE I N TEE
- Page 82 and 83: The storm surke of L&Z1 A.D., knorm
- Page 84 and 85: osi* rn@8IOIP m .SL 4 Has F~~ULB 3
- Page 86 and 87: During the 19th century man starts
- Page 88 and 89: mudflats have retreated some 100-20
- Page 90 and 91: aq811~33a.e~ pue 3pTatlJS uxaJsafi
- Page 92 and 93: Erosion by waves of sandy shoals (c
- Page 96 and 97: Implementafion of the Delta Project
- Page 98 and 99: ECOLOGICAL DEVELOWdENT OF SALT MAKS
- Page 100 and 101: fn tidal water systems sedimentatio
- Page 102 and 103: hierarchical position. Tn the egtua
- Page 104 and 105: Of course. tke environmental change
- Page 106 and 107: wind erasson, desaliuation, aeratio
- Page 108 and 109: Fonner tirtal flats with saltmarsh
- Page 110 and 111: Grevelingen. Lake Veere and Krammer
- Page 112 and 113: As mentioned above aa important que
- Page 114 and 115: A seaond important perspective for
- Page 116: BEEEXNX, W.D. and 80ZBf&. J. L9M. T
- Page 119 and 120: are determining the dfstrlbution af
- Page 121 and 122: this volume or in Duutsaa, et aL, 1
- Page 123 and 124: artificial waterflow was created af
- Page 125 and 126: of waterbirds occur regulsrly. The
- Page 127 and 128: . DISTRIBUXIOBI OF WATEJBIRoS OVER
- Page 129 and 130: small bird$ extludiag them vill net
- Page 131 and 132: In order to lsok for relatiouehips
- Page 133 and 134: Table 3 Biomass of macroroobenthos
- Page 135 and 136: freshwater basins. Clearly the pres
- Page 137 and 138: scmthem bottueary o-f the winter di
- Page 139 and 140: OCLURRENCE AND DIET QF B ~T .tUQ 80
- Page 141 and 142: 5.2 H- factors Next to all fartors
- Page 143 and 144: Bewick's Swans (Cygnus columbariusl
~raffic, however, has irldueed a rfiat<strong>in</strong>er <strong>in</strong>crease of large sale<br />
dredg<strong>in</strong>g activitias fnm about 1970 (Pig. 10).<br />
Figure 10 Impact of dredg<strong>in</strong>g and dump<strong>in</strong>g <strong>in</strong> <strong>the</strong> WeBtefsGhelde 0% <strong>the</strong><br />
development e-f sam&<br />
shod8 {Ww. 198'3)<br />
The drtifieiar deepen<strong>in</strong>g of <strong>the</strong> chhmels hy dredg<strong>in</strong>g llae oontributall ta<br />
an -larrmse of tidal frolume <strong>in</strong> rhe bas<strong>in</strong> of 3 - 73 over <strong>the</strong> period 1970<br />
- 1985 (Van den Be~g. 19871. %keoreticdly (Eis. 4A) <strong>the</strong>se hydraulic<br />
and gwmcrpholo@cal chaqes should <strong>in</strong>voke an ecqanaion of <strong>the</strong> sandy<br />
shoals, Ohserufftkms over <strong>the</strong> period 1955 - 1987 largely coDfim this<br />
(Pia. 187. Future developnte of <strong>the</strong> tide1 landscape will d+psnd<br />
ma<strong>in</strong>ly on <strong>the</strong> actual policy Bf dredg<strong>in</strong>g and dwfs&.<br />
Westee&elde4s<br />
ebb ti4a1 delta skeuld haye shown aa expand<strong>in</strong>g cen&er,cy<br />
over <strong>the</strong> pert98 I970 - 1917 <strong>in</strong> reapwse ts an <strong>in</strong>e.reashg ci.dal valume<br />
km&??a 3eietio-a 2.2). A moz~hoiwgt~al dweveSopuient <strong>in</strong> this sense.<br />
bowever, has bees trmd co &seme over ~h*. past yeam. tidal<br />
laadseirpe eeema W have been aetemhed to if greets* -&end by dredg<strong>in</strong>g. .<br />
sad bovipUg aartiv&ties 6n titre eb21 tidal delta ir~lf. Deepeatris 6f<br />
shfpp&q C&nnB&e and expaturion of Ze@br.aggc ~. harbour roffiated <strong>the</strong><br />
&zedg<strong>in</strong>$ md dwzng &f sbae 4a0. 0;l1IImi mj sededbent otr <strong>the</strong><br />
WasZeec&elae ebb tidal de&a between 197B arrd 1984 [Van den Ems,<br />
1987.). mhss ettriicieal pi~l<br />
.26-bntf1~* to dhtarafnO futuik a&ve1iip*es.
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