DEVELOPMENT OF A SAND SPIT OFFSHORE OF GROIN UNDER HIGH-ANGLE WAVE CONDITION AND EVALUATION OF LONGSHORE SAND TRANSPORT

Abstract

 Shoreline changes around the groins and a sand spit were investigated using satellite images along with the field observation in February 2018, selecting the convex shoreline in the vicinity of Santo Tomas located on the bottom of Lingayen Bay 150 km north of Manila in Philippine. The development of a sand spit over a groin by the instability mechanism under the condition of high-angle wave was studied, and the development of a barrier island with a lagoon inside was predicted by the BG model. The rate of longshore sand transport was also estimated to be approximately 2×10⁵ m³/yr on the basis of the deformation of the shoreline around a sand spit.