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protected by dikes or sea walls do not retreat, due to severe maintenance. 

 The erosion and accretion rates are the smallest (less than 1 m per year) 

 along the central part of the Dutch coast and the largest (more than 10 m 

 per year) in the north along the Wadden Islands (Figs. A. 5, A. 6, and A. 7) 

 (Kohsiek, 1988) . In the figures three bar-graphs are given; the first one 

 gives the trend of erosion/accretion of the low-water line over the last 

 100 years, the second one shows the erosion/accretion also of the low-water 

 line over the last 20 years, and the third one the trend of 

 erosion/accretion of the -4 m line over the last 20 years. 



The northern part (the Wadden Islands) shows great differences both in 

 space and in time of the erosion/accretion rates. The island of Texel is 

 eroding along its whole coast from 2 to 11 m per year as well during the 

 last 100 as during the last 20 years and both for the low-water line and 

 the -4 m line. The other Wadden islands show variable results (Fig. A. 5). 



The central part has an eroding coast in the south and the north and 

 an accreting coast in the middle. The two low-water line graphs 

 representing the last 100 and 20 years show only small differences. This 

 is not the case for the two graphs of the low-water line and the -4 m line, 

 where the differences are remarkable (Fig. A. 6). Partly these differences 

 are due to the groins, causing the erosion of the low-water line to be 

 small or even zero while the shore face (the -4 m line) retreats much 

 faster. It is probable that the retreat of the shore face is already 

 showing the future retreat of the low-water line, which is delayed by the 

 groins . 



In the southern part (the Delta Islands) coastal development is very 

 variable; most parts show erosion, some are stable, and some accrete. The 

 bar graphs of the low-water line for the last 100 and 20 years show great 

 differences due to the Delta works , which influenced the changes of the 

 last 20 years significantly (Fig. A. 7). The two graphs with the trends of 

 the low-water line and the -4 m line over the last 20 years show good 

 agreement. 



During the past 20 years the Dutch coast has lost 5.3 million cubic 

 meters of sand per year along the eroding parts and gained 3.4 million 

 cubic meters per year along the accreting parts. As a whole, the Dutch 

 coast is losing 1.9 million cubic meters per year. 



