Abstract This study examined estuarine morphology and depositional processes in front of lateral river-dominated outlets in a tide-dominated estuary, such as the Lingding Bay in South China Sea. The estuary receives sediments from four deltaic distributary outlets of the Pearl River Delta, of which three outlets (in the western part of the estuary) are river-dominated and one at the head is a tide-dominated inlet. The results obtained from an analysis of historical bathymetric maps and numerical experiments of the sediment dynamics are consistent and indicate that tides predominate the morphological shaping of the lateral river mouth shoals. Accordingly, the eastward progradation of the shoal areas decreased from the upper to lower estuary. The resultant estuarine morphology could be characterised by exponentially decreasing cross-sectional bathymetric areas from the lower to upper estuary. This morphological evolution occurred despite intensive human disturbances. Reduced tidal influences may enhance the southeastwardly deposition of riverine sediments, while increased influences would enhance the erosion of the lateral river mouth shoals. Furthermore, increased tidal influences enhance sediment resuspension and their eastward transportation towards the west trough of the bay, such that lesser sediments are deposited at the river mouth shoals. Hence, it can be concluded that lateral river-dominated outlets in a tide-dominated estuary like the Lingding Bay induce unique estuarine geomorphic features and sedimentary processes that are strongly influenced by tidal action.

中文翻译：

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以潮汐为主的河口侧向河口前河口形态及沉积过程——以南海岭顶湾为例

摘要 本研究考察了以潮汐为主的河口（例如南海的零丁湾）中以河流为主的侧向出口前的河口形态和沉积过程。河口接收来自珠江三角洲4个三角洲分流口的沉积物，其中3个出口（在河口西部）以河流为主，1个以潮汐为主的入口。从历史测深图分析和沉积物动力学数值实验中获得的结果是一致的，表明潮汐在横向河口浅滩的形态塑造中占主导地位。相应地，浅滩区的东进量由上至下河口逐渐减小。由此产生的河口形态的特征是从下到上河口的横截面测深面积呈指数递减。尽管有强烈的人类干扰，但这种形态进化还是发生了。潮汐影响的减少可能会促进河流沉积物向东南方向的沉积，而潮汐影响的增加会加剧对侧向河口浅滩的侵蚀。此外，潮汐影响的增加增强了沉积物的再悬浮及其向东向海湾西槽的输送，从而使较少的沉积物沉积在河口浅滩。因此，可以得出结论，在像零丁湾这样的潮汐主导的河口中，以河流为主的侧向出口诱发了独特的河口地貌特征和受潮汐作用强烈影响的沉积过程。