Detecting and analysis of coast changes of Xiamen Island by RS & GIS

Multi-temporal Landsat images in 1999, 2006 and 2013 were used to reveal the spatial-temporal changes of the coastal locations and types of Xiamen Island. The high tide water levels were extracted as coastline approximations and the coastal types were made by manual interpretation based on Google earth high resolution images in this study. The results indicated that the coast changes mainly happened at the northern and eastern parts of the island. The artificial coast came up to 46.4 km with an increment about 8.8 km due to sea reclamation while the mudflat coast decreased about 18.1 km and faded away from 1999 to 2006. Then there was another increase of artificial coast due to returning ponds back to sea, and the sand coast also increased due to sand supply project from 2006 to 2013. Thus the artificial coast increased to 48.0 km and the sand coast increased from 10.1 km to 16.9 km. The total coastline decreased from 66.4 km to 57.0 km first but then increased back to 65.5 km during the whole period while the island area had a persistent growth from 128.5 km² to 140.0 km². The coastlines moved northward and seaward with less curves due to local constructions except the parts returning ponds back to sea. The rapid social and economic development raised great demand of land use as well as the environmental quality, which made sea reclamation and returning ponds back to sea the main causes of coast changes of Xiamen Island.