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The total dune area of the central coast will diminish, and a strip of 



a width between 80 and 150 m will disappear. Considering a 



strengthening of the dunes (where needed) with sand depletion and not 



by dikes , the consequences for the ecology in this area will not be 



severe. So we assume that beach and coastal slope will be maintained, 

 natural or artificial. 



To the ecology of the Dutch estuarine systems the total extent of the 

 intertidal area of the Wadden Sea area is very important. For some 

 bird species this is the only place where they can feed. A decrease 

 of the intertidal area will certainly result in a smaller number of 

 birds per species and will probably also result in a smaller number of 

 species. In the case of the Wadden Sea, the assumed sea level rise 

 will probably hardly affect the extent of the intertidal area, so 

 impact on ecology will be small. As mentioned previously the residual 

 transports in the Wadden Sea may change. This can affect the 

 ecological system, although it is still very difficult to predict in 

 what way. The impact of temperature rise on the ecology is a totally 

 different question, which cannot be answered yet. 



In the Eastern and Western Sheldt of the Delta area the intertidal 

 area is likely to decrease. This has the negative consequences 

 mentioned above. The species concerned are mainly migratory birds 

 (e.g., stilts). 



In the lower parts of the river systems in the Netherlands, mean and 

 extreme water levels will rise as well. The river forelands which now 

 only get flooded occasionally during the winter will get flooded more 

 frequently or will be flooded most of the time. The peculiar ecology 

 of these will change or disappear. 



Economic Implications - With a 1-meter sea level rise over a century, 

 present maintenance costs for coastal and river defense systems would 

 approximately double. The present cost of coastal maintenance amounts to 

 about 60 million guilders per year. The strengthening of dikes, dunes, 

 beaches, and shore faces over the next century would cost about 6 billion 



