珠江伶仃洋河口湾动力地貌格局的异变研究

The Pearl River Estuary is a unique estuarine system consisting of river networks and estuarine bays connected by 8 river mouths. The mutations of the evolution pattern of both the river networks and estuarine bays in the Pearl River Estuary have occurred driven by strong human activities and the magnitude of such change has exceeded that caused by natural factors. In this study, the Lingdingyang bay is selected as the study area to examine the mutation of morphological pattern in the estuarine bay under the influences of strong human activities considering the river network and estuarine bay as an interactive estuarine system. Based on the analysis of the relevant historical data including hydrology, observed velocity and sea chart data, three mooring stations are deployed at the eastern groove, western groove and middle shallow according to the morphological pattern with three shallows and two grooves of the Lingdingyang bay, respectively. Time series data on the hydrology and sediment condition at three mooring stations were obtained simultaneously for 26h in the spring and neap tide in the flood and dry seasons, restively; and sea-bottom sediment samples are collected in the Lingdingyang bay in the flood and dry seasons, respectively. The mutations of hydrodynamic and sedimentation patterns in the Lingdingyang bay are explored from the viewpoint of strong anthropogenic impacts including sand excavation, reclamation and dredging. With the method of numerical modeling, the critical water depth of the western groove in the Lingdingyang bay is numerically tested, and the effects of estuarine reclamation and dredging on the changes of hydrodynamic pattern in the bay are modeled. On the above basis, the methods of analytic solutions and dynamic geomorphology are applied to explore the evolution processes, evolution tendency and evolution pattern changes of morphological pattern with three shallows and two grooves in the bay, and then the mutation mechanism of dynamic geomorphology pattern in the bay are discussed.

珠江河口是由八大口门联结的"网河区-河口湾"独特河口系统，在超强人类活动驱动下，珠江河口网河区、河口湾的演变格局已发生超自然过程的异变。选取伶仃洋河口湾为研究靶区，并把"网-湾"视为相互作用的有机河口系统，研究超强人类活动驱动的河口湾地貌格局的异变。收集相关水文资料、历史测流资料及历史海图资料，根据伶仃洋河口湾"三滩两槽"的地貌格局，分别在伶仃洋东、西两槽及中滩共布设3条垂线，进行洪、枯两季大、小潮过程的26小时逐时同步水文测验，并采集洪、枯水期表层沉积物样品，以采沙、围垦和疏浚等超强人类活动为切入点，分析伶仃洋河口湾动力格局和沉积格局的异变，结合数值模拟方法，进行西槽浚深临界水深的数值试验，并模拟伶仃洋围垦、浚深对河口湾动力格局变化的影响，在此基础上，采用解析解分析方法及动力地貌方法，揭示河口湾三滩两槽的演变过程、变化趋势及演变格局的变化，进而探讨河口湾动力地貌格局异变的机制。

珠江河口是由八大口门联结的“网河-河口湾”独特河口系统，在超强人类活动驱动下，珠江河口网河、河口湾的演变格局已发生超自然过程的异变。本项目以伶仃洋河口湾为研究靶区，并把“网-湾”视为相互作用的有机河口系统，研究超强人类活动驱动河口湾地貌格局异变。项目执行期间，收集了大量伶仃洋河口湾相关水文资料、历史测流资料及海图资料，并开展了洪枯季大小潮多船同步水文泥沙观测及河口湾表层沉积物洪枯季采样；以采沙、围垦和航道疏浚等超强人类活动为切入点，分析伶仃洋河口湾动力格局和沉积格局的异变，结合数值模拟方法，通过设置不同情景模拟伶仃洋围垦、疏浚对河口湾动力格局变化的影响，在此基础上，采用解析分析方法及动力地貌方法，揭示河口湾三滩两槽的演变过程、变化趋势及演变格局的变化，进而探讨河口湾动力地貌格局异变机制。项目执行期间共发表9篇高水平学术论文，其中SCI学术论文6篇，培养1名博士后和7名硕士研究生，研究结果以分析伶仃洋河口湾动力格局异变、沉积格局异变为基础，进而探讨超强人类活动驱动的伶仃洋河口湾动力地貌格局的异变，分析其演变趋势，揭示其异变机理, 为伶仃洋的岸线利用、航道疏浚、河口治理等提供科学依据。