中国海岸近期侵蚀问题

RECENT EROSION OF CHINESE COASTS

中国海岸侵蚀主要出现于废弃三角洲前缘地带和现代三角洲局部地区。其次出现在堆积性海岸阶地或沙坝区域。 河流沉积中心转移、流域来沙减少、河口水动力变异是废弃三角洲和现代三角洲侵蚀的重要条件;陆架供沙不足是海岸砂质堆积体蚀退的主要原因;较高能量的海浪、风暴和近岸水流作用是海岸侵蚀的主要动力因素;海平面上升对海岸蚀退有一定影响。 目前,中国海岸侵蚀仍在继续。今后,随着海岸带的开发建设,必须重视对海岸侵蚀的防护。

The Chinese coastline stretches more than 30,000km.Coastal erosion occurs mainly in abandoned delta fronts and some regions of modern deltas, such as in Paleo-Luanhe delta, the north part of Huanghe delta, the abandoned Huanghe delta, and the Nandujiang delta. There is also erosion in accumulative shore-terraces and sand barriers.The shift of sedimentation is focussed in the estuary, the decrease of sediments from drainage and the change of estuarine dynamics are important conditions for the erosion in abandoned and modern deltas. The shortage of sediments supplied from the continental shelf is the chief cause for the erosion in coastal sandy accumulative bodies. The action of waves with high energy, storms and near-shore currents are the main dynamical factors for erosion in coastal zones. Sea-level rise has ,some impacts on coastal erosion and retrogress.Up to now coastal erosion in China still continues. with the exploitation and construction along the coastal zones, it is necessary to pay attention to the prevention of coastal erosion in the future.