Cyclic morphologic changes of the ebb-tidal delta, Texel Inlet, The Netherlands

Abstract

Cyclic morphological changes occur in the ebb-tidal delta system of Texel Inlet (The Netherlands). This geomorphological cycle lasts about 70 years. The cycle starts with the development of a main ebb channel in the southern half of the inlet. A large ebb delta shoal forms north of this ebb channel. The shoal grows upwards into the inter- to supra-tidal zone and moves eastwards under the influence of wind and waves. The flood channel north of the shoal is forced to rotate clockwise, and it approaches the shoreline of Texel. The marginal ebb channel in the southern part of the inlet develops due to the tidal currents deflected to the south by the eastward migrating shoal and slowly rotates clockwise, forced by the small flood marginal channel that adjoins the mainland coast to the east. The cycle is completed by shoal attachment to the southern tip of Texel Island, which causes the northern marginal channel of the inlet to be buried. The eastward migration rate of the shoals is about 60-70 m per year, which involves a sediment transport rate of order of 580 to 0.64 x 106m3/year.