瑞丰沙变迁对长江口南港河床特征影响

Impact of Ruifengsha's changes on riverbed characteristics at the south channel of the Yangtze River estuary

根据长江口南港河段历史地形资料、1998年以来历年4次固定断面水深测量资料,分析瑞丰沙的形成、发育以及冲刷过程,重点分析近10余年来瑞丰沙变迁对南港河段河槽容积、过水断面面积及断面形态的影响。研究表明:1)近年来,瑞丰沙上段保持相对稳定的态势,下段逐渐消亡,这与人类工程及无序采砂密不可分;2)瑞丰沙的变迁,对南港河槽有重要影响,南港上游断面面积保持稳定,下游断面面积明显减小,河槽容积逐年增大,深槽淤浅,靠岸,都与瑞丰沙的变迁密不可分。3)应采取积极措施抑制不利影响。

Based on the historical bathymetry data of the south channel of the Yangtze River estuary, and water depth of the fixed cross-sections for four times every year since 1998, we analyze the process of formation, development and erosion process for Ruifengsha, focusing on the influence of Ruifengsha＇s change on the channel volume, wetted cross-sectional area, and cross-sectional shape at the south channel during recent decade. The results show that： 1） In recent years, the upper part of Ruifengsha has been in the stable status, and the lower part has gradually disappeared, which is caused by human engineering and disordered sand excavation. 2）Ruifengsha＇s changes have significant impacts on the south channel. There is an inseparable relationship between Ruifengsha＇s changes and the phenomena such as the cross-sectional area keeps unchanged at the upstream, and it obviously decreases at the downstream of the south channel, the channel volume constantly increases, the deep channel deposits, becomes shallow, and turns to shore. 3） We should take positive measures to diminish unfavorable influences.