Environmental impacts of shore-parallel breakwaters along Nagahama and Ohgata, District of Joetsu, Japan.
A combination of sedimentological analysis of beach sands, field surveys and the assessment of the empirical methods for the breakwater design is used to investigate the impacts of offshore breakwaters on beach morphology along Nagahama and Ohgata. The results indicate that the nearshore sedimentation has been substantially disrupted due to the features formed behind the breakwaters stopping littoral transport, which led to sediment accretion on the updrift side of the breakwaters, and erosion on their downdrift side. Sedimentological analysis of beach sands made it possible to recognize the dominant process at the sections considered. In fact, the occurrence of strong offshore-going currents, the removal of finer mean grain size and the predominance of high-density heavy minerals led us to deduce that the two sections undergo a natural sedimentary imbalance.
Sane
Moussa
M
Niigata University, Graduate School of Science and Technology, Department of Environmental Sciences, Faculty of Sciences, Igarashi 2-no-cho 8050, Niigata city 950-2181, Japan. moussamohamedsane@yahoo.fr
Yamagishi
Hiromitsu
H
Tateishi
Maasaki
M
Yamagishi
Toshio
T
D001493:Bathing Beaches; D004777:Environment; D019015:Geologic Sediments / Q000032:analysis*; D007564:Japan; D008903:Minerals / Q000032:analysis; D009792:Oceans and Seas; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D014872:Water Movements
D008903:Minerals; D012822:Silicon Dioxide