MECHANISM OF OFFSHORE SAND DISCHARGE INTO SUBMARINE CANYON TRIGGERED BY CONSTRUCTING DETACHED BREAKWATER CLOSE TO SHORELINE

[摘要] Several submarine canyons have developed offshore of the Aramata region of the Shimoni-ikawa coast in ToyamaBay, which is one of the three deep bays in Japan. The Kurobe River with a steep bed slope flows into the seaimmediately north of this region, and a large amount of sediment has been supplied to this area, which has beentransported by southward longshore sand transport. However, beach erosion has occurred owing to the decrease in sediment supply from the Kurobe River. Furthermore, since the construction of detached breakwaters as a measureagainst beach erosion, offshore sand transport has accelerated and beach erosion has become more severe. In thisstudy, aerial photographs and bathymetric survey data were analyzed, then the mechanism of offshore sand transportwas investigated using the BG model proposed by Serizawa et al. (2007).

[学科分类] 建筑学

[关键词] submarine canyon;offshore sand transport;detached breakwater;Shimoni-ikawa coast