Abstract
The controlling effect of longshore sand transport using groins (ordinary-type, groin of low-crown height, groin with an opening near the shoreline, submerged, slit-type groins) was investigated using the BG model (a three-dimensional model for predicting beach changes based on Bagnold' concept). When the landward end of the groin is located at the shoreline, the rate of passage of longshore sand transport is as high as 74%, resulting that almost all longshore sand transport discharges downcoast while losing the groin effect. This condition corresponds to the case in which an opening is formed at the landward end of a groin as a result of shoreline recession. Furthermore, in case of slit-type groin, the rate of longshore sand transport increases because of the passage of longshore sand transport through the slits, and its effect is low.
