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Coastal dunes are one of the characteristic landscapes in Anmyeon Island,Korea,and most of them have economic values as reservoirs of high quality silica,the raw material for making glass.During the government-driven development period (1960s-1980s),sand mining was actively conducted in many of coastal dune area in Anmyeon Island by private firms under the support of Korean government.The other values of coastal dunes,however,have long been neglected even though coastal dunes act as natural buffers against coastal storms,fresh groundwater reservoirs in coastal area,and a unique habitat of endangered species.As a result,lots of coastal dune areas were severely damaged or totally destroyed by sand mining activities.Unyo Dunes in Anmyeon Island show how sand mining and related activities altered the coastal dune dynamics.Firstly,sand mining activities removed huge amount of coastal dune sands in a direct sense.Volumetric analysis using digital elevation models of Unyo Dunes,generated from three different stereo airphotos taken in 1977,1989,2003,reveals that total quantity of sand removal since 1977 exceeds 106 m3,equivalent to the lowering of elevation by the 8.3m on average across the coastal dune area.Besides,seawall construction to secure the inland sand mining activities from coastal erosive forces exacerbated the erosion in the frontal beach,which caused repeated failure of seawall structure.Also,restoration actions with pine tree planting often failed because of high groundwater table.Furthermore,the reflective effect of seawall on the incident wave reinforced longshore sand drift to the nearby port,arousing the siltation problem of the main waterway.After all,breaching of seawall occurred in 2007,and the frontal beach and coastal dune landscape dramatically changed.The case of Unyo Dunes suggests that sand mining and related activities be carefully conducted in coastal dune areas,even when they seem economically promising.Ill-managed sand mining and related activities such as seawall construction and inappropriate planting project could alter the coastal dune conditions in an irreversible way.Considering the roles of coastal dunes in coastal systems,sand mining and related activities should be conducted not to damage the buffering capacity of coastal dunes.