中国海岸侵蚀述要

COASTAL EROSION IN CHINA

中国近代海岸侵蚀自50年代末期日渐明显,70年代末期加剧。目前约有70％的沙质海岸和大部分开敞的粉砂淤泥质海岸遭受侵蚀。人工挖沙和河流输沙减少是侵蚀发生的主要原因。海岸侵蚀已危及沿岸房舍、道路、海岸工程、旅游资源。

Since the end of the 1950s', coastal erosion has taken place extensively in China and has been accelerated. At present, nearly all of the muddy coasts and 70% of the Snady coasts are subject to erosion. Coastal erosion has threatened villages, roads, factories coast-protection forests and tourism resources. The speed of erosion of muddy coasts changes considerably from place to place while that of the sandy coasts ranges between 1 and 2 m/ yr in general. The coral-reef coasts and platform coasts are subject to serious erosions too. The coasts located to the north of the Yangtze River are more seriously eroded than those to the south of the river. Intense coastal erosion has taken place in the provinces of Jiangsu,Shandong,Hebei and Liaoning and in Tianjing Municipality, all of them are located to the north of the Yangtze River. While to the south of the river, strong coastal erosion occurs only along the coasts in Fujian and Hainan provinces. The main causes of coastal erosion in China are the quarrying of sands and the decrease of sediment discharges of the rivers into the sea. It is estimated that about 4000 million tons of beach sands have been exploited annual throughout the country, while the decreased amount of river sediment discharge into the sea is much larger than the amount of beach sands exploitation. The annual sediment discharge of the Huanghe River in the 1980s' was decreased over 300 million tons compared to the average. Sea level rise and ground subsidence in the future 50-100 years will cause the lowlying coastal areas in China to be subject to seawater transgression, and coastal erosion will cause a great loss of land area in China.