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基于长江河口1959-2011年实测悬沙浓度数据,通过对河口最大浑浊带外围海域泥沙要素分析的基础上,研究了近期流域人类活动和河口整治工程对最大浑浊带悬沙浓度的影响。研究表明:①流域人类活动对入海水量影响较小,无明显趋势变化,而沙量和含沙量呈现锐减趋势,也使得进入河口区域的泥沙量呈现一致锐减;②长江口外海域和南部杭州湾海域悬沙浓度变化不大,北部苏北沿岸略有减小,因数值较长江口海滨区小约1个数量级,对浑浊带影响较小;③最大浑浊带位置受径流和潮流控制,面积变化与入海沙量多寡关系密切;④整个浑浊带区域悬沙浓度受入海沙量锐减决定,2000-2009年较1959-1999年悬沙浓度减小约为24.73%,向海延伸减幅降低,且峰值区域向口内移动,泥沙再悬浮作用对维持最大浑浊带悬沙浓度起调节作用,但不能决定其锐减趋势;⑤北槽航槽最大浑浊带的悬沙浓度向海为低—高—低变化特点,受入海沙量锐减、北槽分流分沙比减少及床沙粗化等影响,使其上段和下段悬沙浓度减小趋势,而中段受南导堤越堤沙量的影响悬沙浓度呈增加趋势。
Based on the data of suspended sediment concentration in Yangtze River Estuary from 1959 to 2011, the influence of human activities and estuary remediation works on the suspended sediment concentration in the maximum turbidity zone was studied based on the analysis of sediment elements in the sea area outside the maximum turbid zone. The results show that: (1) Human activities in the basin have less influence on the water inflow into the sea, and there is no obvious trend change, while the sediment concentration and sediment concentration show a decreasing trend, which also leads to a consistent decrease of the sediment input into the estuary. (2) The concentration of suspended sediment in the southern Hangzhou Bay was not much changed and slightly decreased in the northern part of the northern Jiangsu Province because the value was less than one order of magnitude lower than that in the estuary of the estuary and had less influence on the turbid zone. The location of the maximum turbidity zone was affected by runoff and flow control , The change of area is closely related to the amount of sediment entering into the sea. (4) The suspended sediment concentration in the whole turbid zone is determined by the sharp decrease of sediment concentration into the sea. The suspended sediment concentration decreases by 24.73% from 1959 to 1999 from 2000 to 2009, The amplitude of suspended sediment concentration in the maximum turbidity zone in the North Channel slot toward the sea is Low-high-low variation characteristics. The suspended sediment concentrations in the upper and lower sections decreased due to the sharp decrease of sediment input into the sea, the decrease of diversion and sedimentation rates in the north channel and the coarsening of bed sediment. In the middle section, Impact of Sand Suspended sediment concentration increased Trend.