Sand movement in the in- and offshore tidal area of the S.W. part of the Netherlands

Abstract

This paper deals with the resultant sand movement over the offshore underwater delta along the tidal inlets of the S.W. part of the Dutch coast and with the sediment exchange between the North Sea and the underwater delta. It appears that a complicated circulation of sediments occurs in the whole channel system in the area, mostly directed perpendicular to the general coastline. On the shoals the sand transports by currents are almost negligible. The picture of sand movement by waves suggests a net northeastern sand transport over the shoals. Also the data derived from sediment balances and grain-size differences point to a net northeastern movement of fine sand over the underwater delta. The direction of the sand transport by currents and grain-size data reveal that there is an appreciable sediment exchange between the underwater delta and the North Sea in the Haringvliet area and apparently also along the southwestern part of the underwater delta.