黄河三角洲整体冲淤平衡及其地质意义

THE ROUGH BALANCE OF PROGRADATION AND EROSION OF THE YELLOW RIVER DELTA AND ITS GEOLOGICAL MEANING

海岸侵蚀、三角洲面积减小已成为世界上关注的热点问题。三角洲造陆的趋势及速度制约着三角洲地区经济的持续发展和生态环境的演变。本文以 1976、1986、1992、1996～ 1998年黄河三角洲卫星遥感照片及海区水深等实测资料为依据 ,通过其高潮线的对比分析 ,研究整个黄河三角洲面积变化的趋势。结果表明 ,黄河三角洲在整体淤进的同时伴随着蚀退 ,三角洲的造陆面积呈逐渐减小的趋势。通过对 195 0～ 1998年黄河利津站实测来水来沙资料的分析 ,发现近年来水沙呈递减趋势 ,这可能是三角洲造陆面积减小的重要原因。研究了黄河三角洲造陆面积与流域来水来沙的关系 ,从而得出当来沙量为 2 .45亿 t/ a时 ,三角洲面积整体趋于不冲不淤的平衡。若来水来沙量继续减少 ,黄河三角洲将走向全面蚀退 。

Coastal line erosion and delta area decrease are becoming a hotspot for governments and scientists in the world.The trend and velocity of formed land restrict the economic development and ecological environment evolvement in delta area.According to coastal line changes during the high tidal periods of 1976,1986,1992,1996,1997 and 1998,the trend of progradation and erosion of the Yellow River delta was studied.The results show that the coastal line progradation and erosion are proceeding simultaneously,and generally the formed land area in the delta is decreasing.The results of water discharge analysis and sediment load from 1950 to 1998 and their relation to the formed land area show that when sediment load is 2 45×10 8 t,the delta of the Yellow River will have rough balance of progradation and erosion.