珠江磨刀门河口排洪动力特征及拦门沙演变响应的初步研究  

The dynamics of flood releasing and its effects on the morphological evolution of the mouth bar in the Modaomen Estuary of the Pearl River

作　　者：谭超[1,2,3] 黄本胜[1,2,3] 龚文平[1,3] 邱静[2,3] 

机构地区：[1]中山大学海洋学院,广东广州510275 [2]广东省水利水电科学研究院广东省水动力学应用研究重点实验室,广东广州510630 [3]河口水利技术国家地方联合工程实验室,广东广州510630

出　　处：《水利学报》2013年第9期1023-1029,共7页Journal of Hydraulic Engineering

基　　金：国家自然科学基金资助项目(21077139);广东省科技计划项目(2010A030200016);2011年广东省水利科技创新项目

摘　　要：磨刀门河口是珠江八大口门中输水输沙量最大的河口,口外拦门沙发育,其泄洪安全一直是磨刀门口门治理的头等大事。本文基于2003年洪季磨刀门河口拦门沙水域水文观测资料及近年典型洪枯季河床地形资料,分析了河口拦门沙排洪动力特征及拦门沙典型地貌单元对洪水的响应规律。研究结果表明:磨刀门拦门沙水域洪水季节水体分层明显,表现为浮力射流;外海高盐水被拦门沙阻挡,无法越过拦门沙向里侵入;拦门沙对洪水的壅水作用主要表现为低水位的壅高,灯笼山站与大横琴高潮位及低潮位水位差均和马口流量有较好的线性正相关关系。由于洪水季节磨刀门河口径流占显著优势,洪水成为拦门沙演变的主要动力,通过拦门沙典型地貌单元年际、年内演变特征分析发现,在洪水的冲决下拦门沙东、西汊得到较快发展,其中东汊的冲决效果更强烈,当洪水来临时东汊成为排洪的重要通道;洪水对交杯四沙冲刷作用较明显,特别是交杯四沙内侧南北向并岸沙堤易被洪水冲开;受洪水冲刷影响,拦门沙西汊前缘次一级分汊体系的雏形已经形成。The Modaomen Estuary, as one of the eight ＇gates＇ which connects the complicated stream net- work of the Pearl River and the estuarine bays, is the most important in discharging freshwater and sedi- ment into the estuarine bays. However, there is immense bar area evolved in the outer subaqueous delta. Consequently, the flood releasing safety is the most important issue in the regulation project of the estuary. This paper is to investigate the dynamics of flood releasing in the mouth bar of the Modaomen Estuary, as well as the morphological response of the mouth bar to the flood, based on the analysis of the field data collected in 2003 and bathymetric data of recent representative years. The results show that in the flood sea- son the water column in the bar area was highly stratified, characterized as buoyancy plume, while the in- truded salty water from the adjacent sea was blocked by the mouth bar. The water damming effects of the mouth bar on the flood was displayed as the raised low water level. The differences in the water levels at the Dahengqin and Makou stations during high and low tides corresponded well with the discharge of the Makou station. In flood seasons, the Modaomen Estuary is river dominated, and the flood is the main forc- ing agent which controlled the morphological evolution of the mouth bar. With the flushing of the flood, both the east and west channels devolved, especially the east channel, suggesting that the east channel was the main path for the flood releasing. The flushing of the flood on the Jiaobeisisha was also signifi- cant, especially the coastal barrier in a north-south direction can be easily separated. Under the effects of the flood flushing, the sub-distributaries of the west channel originally formed.

关 键 词：磨刀门河口 排洪动力特征 拦门沙演变 

分 类 号：TV143[水利工程—水力学及河流动力学]