Abstract
Artificial changes around a coral cay caused by human activity were investigated using the BG model (a 3-D model for predicting beach changes based on Bagnold's concept). Numerical simulations of beach changes on a coral cay were carried out after the successive construction of detached breakwaters. After the construction of the breakwaters, tombolos formed behind the breakwaters owing to the wave-sheltering effect of the breakwaters. As a measure against beach erosion on both sides of the detached breakwaters, further measure was required, and finally, the entire shoreline of the coral cay was covered by detached breakwaters, resulting in an artificial coastline.
