A NEW SEDIMENT BUDGET FOR THE NETHERLANDS; THE EFFECTS OF 15 YEARS OF NOURISHING (1991-2005)

摘要

In 1990, the Dutch government decided to halt structural coastal erosion with sand nourishments. This paper presents a sediment balance over the period 1990-2005, the first fifteen years of nourishing, in order to establish the results. The overall net sediment budget of the Dutch coast is still negative due to erosion of the lower shoreface and the ebb-tidal deltas: -159.8 million cubic meter (mcm). However, the budget shows that the accretionary status of the upper shoreface, beach and frontal dunes has changed to positive. The natural volume trend over the period 1990-2005 is -41.5 mcm. With a nourished volume of 118.6 mcm this zone has a net gain of 77.3 mcm. Especially the Holland coast has a very positive sediment budget: a gain of 23.3 mcm. The conclusion of this study is that the aim of the Dynamic Preservation policy is achieved: coastal recession has been stopped.