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上海地处长江、东海、杭州湾的交汇处,长江和钱塘江每年约有5亿吨泥沙流失下泄,在下游段因江面展宽,流速减缓,又因受风浪、江流、海流等因素的交替作用,使泥沙在河口附近逐渐沉积成陆,形成大片的近岸浅滩,为围海造地创造了有利的条件.多年来,上海市结合工业建设,港埠码头开辟,航道整治和疏浚,海塘护岸工程整修,扩大市郊副食品基地建设以及农业围垦等的需要,在沿江、沿海先后围海造地共约80万亩,促进了工农业生产和各项建设事业的发展,少占了现有耕地.
Shanghai is located at the confluence of the Yangtze River, East China Sea and Hangzhou Bay. Each year, about 500 million tons of sediment are discharged from the Yangtze River and Qiantang River. Due to the widening of the river surface at the lower reaches, the flow rate is slowed down. Due to such factors as storms, Alternate action, so that sediment gradually deposited in the estuary near the land, the formation of large coastal shoals, creating favorable conditions for land reclamation.For many years, Shanghai combined with industrial construction, port pier development, waterway regulation and dredging, seawall The renovation of revetment projects, the expansion of the construction of non-staple food bases in the suburbs, and the need for agricultural reclamation. About 80 million mu land has been built along the coast and along the coast to promote the industrial and agricultural production and various construction projects, .