南黄海辐射沙洲内缘区演变驱动机制及围垦布局研究

【作者】 李飞；

【导师】 徐敏；

【作者基本信息】 南京师范大学 ， 自然地理学， 2014， 博士

【摘要】 辐射沙洲内缘区是潮波系统的汇合区,潮滩持续淤长提供了巨大海岸空间资源利用潜力,潮沟频繁摆动使得滩槽变化剧烈,演变驱动机制研究可为内缘区复杂动力环境下的潮滩围垦开发提供技术支撑。本论文通过收集整理并系统分析辐射沙洲海域水文、地形、遥感等调查研究资料,构建了辐射沙洲地理数据库,结合前人研究成果,进一步梳理分析了辐射沙洲宏观演变背景与动力格局,采用遥感、GIS技术和数值模拟技术等多种研究方法和手段进行内缘区演变驱动机制的研究,在此基础上,根据内缘区潮流数学模型,研究并提出了辐射沙洲内缘区的围垦布局原则和方案。(1)根据1973年～2013年的遥感影像和实测地形数据,采用GIS技术从多角度系统分析了“水道-沙洲系统”宏观演变特征和近期动态。“水道-沙洲系统”格局演变特征表现在以下几个方面：“水道-沙洲系统”组合形态基本稳定；潮滩规模相对稳定,总体态势外冲内淤；靠岸潮汐通道的岸向迁移；南北两翼在形态及演变动态上存在空间分异。(2)辐射沙洲内缘区“沙洲-水道复合系统”演变特征总体表现为：内缘区稳定淤长、滩槽多变；内缘区南北向潮汐通道的稳定存在,主槽迁移转换；内缘区近期水道组合态势表现为高泥淤长、豆腐渣腰门水道北移、西大港和东大港的南北串通。(3)1970年以来,辐射沙洲内缘区的演变过程可划分为四个阶段：1970s陈家坞时期(完整沙洲期)、1980s动力相对平衡时期、1990s西大港时期、2000年以后东大港时期。(4)对内缘区演变机制的认识：内缘区是两大潮波系统的汇合区域,潮波辐合区域呈动荡性特征；辐射沙洲内缘区南北两侧水体通道的稳定存在；内缘区东部高泥持续扩张使得陈家坞槽尾部南北向通道逐渐萎缩淤死,西大港和东大港潮沟系统的演变实质内缘区南北向通道主槽西移过程中的适应性发展；在外部环境稳定背景下,内缘区将总体表现为南北向主槽通道相对稳定和分支潮沟系统的动态多变。(5)辐射沙洲内缘区是规模最大的低潮出露沙洲区,但由于其位于两大潮波辐合区,潮汐水道在此处汇合贯通,使得其水动力环境复杂,滩槽冲淤多变。潮滩围垦布局需与潮流动力场相适应,维持现有潮汐动力格局的稳定性。内缘区围垦布局的基本原则：①保持南北水道的贯通。②保留水道“裂点区”。③西大港摆动退让。(6)依据研究提出的内缘区围垦原则,论文提出大、小两类8种围垦布局总体方案。根据不同围垦布局方案的潮流动力和通量变化响应分析,论文推荐小规模区块式围垦布局方案。由于北尖子围区和高泥北围区滩面较为稳定、汇水潮沟系统发育不显著,是优先推荐的围垦区域。高泥南围区所在滩面是东大港与南侧水体的汇水区,滩面潮沟系统发育明显,围垦条件较为复杂,在区域围垦需求不显著时,建议限制开发。论文创新性体现在：①基于辐射沙洲海域的地貌形态特征和动力特征,提出了基于控制性动力的辐射沙洲“水道-沙洲系统”动力地貌系统的分区方案；②提出了辐射沙洲内缘区的年代际演变阶段特征,揭示了内缘区潮流动力环境变化过程及机制；③提出了内缘区潮滩围垦布局基本原则,在此基础上确定了沙洲内缘区的小规模区块式围垦布局方案。更多还原

【Abstract】 Inner part of radial sandbanks (IPRS) is the convergent region of tidal systems in the South Yellow Sea. The continuous growing of tidal flat provided large using potential of coastal space resources. The frequently swings of tidal creeks induced the changes between scouring and silting greatly. Research on the driving mechanism of geomorphological evolution can support the reclamation in the complex dynamic environment of the IPRS. Hydrological data、topographic data^and remote sensing images in radial sandbanks were collected and systematically analyzed, and were integrated in the geo-database built. Combined with previous research, this paper carded and analyzed the macro evolution background and dynamic pattern of radial sandbanks, studied the driving mechanism of geomorphological evolution of IPRS with numerical simulation, remote sensing and GIS techniques. Based on the tidal flow mathematical model of IPRS, the principles and layout schemes of reclamation of IPRS were studied and proposed.(1) Based on the remote sensing images of1973-2013and the topographic data, this paper analyzed the characteristics of macro evolution and recent developments of "water channel-sandbar system" with GIS techniques from different perspectives. The evolution characteristics of "water channel-sandbar system" performed as the following aspects:The basic combination form of "water channel-sandbar system" was at the status of stability. The scale of tidal flat remained relatively stable with the current situation of inside part silting while external part washed. Tidal channels close to the shore were moving towards coast. The north part and the south part differ in the forms and the evolution trends。(2) The evolution characteristics of "water channel-sandbar compound system"(IPRS) performed on these aspects:The inner part kept prograding and the swales were highly variable. The north-south tidal channels of inner part exist for a long time and the main channel changed from one to another. The combination situations of channels of inner part in recent years shown the prograding of Gaoni, the north toward moving of Doufuzha and the north-south connection of Dongdagang and Xidadang.(3) Since1970, the evolution of IPRS could be divided into four stages:1970s-Chenjiawu period (integrated sandbanks),1980s-the relative balance period, 1990s-Xidagang period, after2000-Dongdagang period.(4) The understandings of evolution mechanisms on IPRS:IPRS was the convergent region of the two tidal systems, where turbulent change was its main characteristics. The existence of north-south tidal channels was stable in IPRS. The north-south tidal channel in the tail of Chenjiawucao was gradually silting with the Gaoni expanding. The innate character of the Dongdag and Xidagang’s evolution was the westward of north-south main channel. With the stability of the external environment, the general characteristics of IPRS was the sustained existence of north-south tidal channels and the dynamically changes of branch tidal creek system.(5) Although IPRS has the largest sandbanks, its hydrodynamic environment is complicated, due to the feature of tidal flow convergence zone. The tidal flat reclamation layout should adapt to the trend of dynamic field, so as to maintain stability of the existing tidal power pattern. The basic principles of layout in IPRS were the follows:maintaining the north-south tide channel, reserved the "split point areas" of channel, avoiding the swinging zone of Xidagang.(6) Based on the reclamation principles of IPRS, eight schemes for two kinds of reclamation spatial layout were proposed. According to the analysis of response for tidal power and flux between the two kinds of schemes, the small-scale of block-layout was recommended. Due to the stability of tidal flat and the tidal creek systems changes, the reclamation areas of Beijianzi and Gaonibei were the priority areas. At the time the reclamation demand is not significant, the reclamation area of Gaoninan was the restricted area for its complexity of tidal flat and the tidal creek systems.更多还原