长江河口水沙分流和输移的探讨

据2002年9月长江口同步实测水文资料,运用标准水文法,对南、北支和南、北港的落潮分水分沙比和净泄分水分沙比进行了计算。结果表明,两者存在差异,后者更能反映分水分沙在长江河口演变中的作用,“涨潮汇沙比”更能揭示北支泥沙的倒灌。水沙平衡分析结果表明,观测期间北支仍趋于淤积,南支有冲刷迹象。经多站水沙综合分析,揭示了长江口水沙运动具有径流“主体南泄”、汊道“副淤主刷”和水沙“输移分异”等特征,并指出水沙“输移分异”是北港泥沙输运大于南港的原因之一。

An Approach to Water and Sediment Diversion Ratios and Transports in the Changjiang River Estuary Area

In this paper,the ebb water and sediment diversion ratios and the net discharge water and sediment diversion ratios in the Changjiang River estuary area are calculated by using the hydrographic data observed in the estuary area in September,2002 and the standard hydrodynamic method.It is shown from the calculated results that the ebb water and sediment diversion ratios are different from the net discharge ones,the net discharge diversion ratios are more capable of reflecting the effects of water diversion and sediment diversion on evolution of the Cahgjiang Rover estuary,and the sediment influx ratio is more capable of indicating the sediment influx into the north branch.It is shown from the flow and sediment balance analysis results that there were siltation in the north branch and erosion in the south branch.The analysis results also expound the water and sediment movement characteristics,and the differentiation between water transport and sediment transport is one of reasons for the sediment transport in the north channel greater than that in the south channel.