废黄河三角洲海岸演变及侵蚀脆弱性评估

发布时间：2019-06-13 13:34

【摘要】：苏北废黄河三角洲自1 855年黄河北归入海之后,成为我国海岸侵蚀最为严重的区域之一。了解废黄河三角洲的演变规律,不仅可以给废黄河三角洲海岸侵蚀防护提供参考,同时也可以对其他三角洲,尤其是现代黄河三角洲的演变规律和侵蚀防护提供借鉴,因而废黄河三角洲演变研究一直都是三角洲海岸侵蚀防护研究的热点。对废黄河三角洲海岸侵蚀脆弱性评估,了解不同岸段侵蚀脆弱性现状,可以为废黄河三角洲海岸侵蚀防护,海岸带资源开发利用、海岸带规划管理决策等提供参考。本文以多期遥感图像、海图资料、前人研究成果以及野外实测资料为主要数据源,结合遥感(RS)、地理信息系统技术(GIS)和数字海岸分析系统(DSAS),研究废黄河三角洲海岸演变特征。根据研究区特点,选取岸线变化速率、等深线变化速率两个海岸动态因子,岸滩坡度、水下坡度、沉积动力环境三个海岸形态因子,年平均含沙量、年平均高潮位两个水动力因子,以及海岸利用类型、海岸开发适宜性两个社会经济因子等9个评估指标,并用层次分析法(AHP)求得各指标权重,构建海岸侵蚀脆弱性评估体系。最后,通过计算海岸侵蚀脆弱性指数(CVI)对废黄河三角洲海岸侵蚀脆弱性进行评估。研究结果表明：(1)废黄河三角洲形成和演变主要分五个阶段：发育前期、缓慢发育期、快速发育期、沙洲并陆调整期以及侵蚀后退期。(2)废黄河三角洲现代侵蚀后退演变具有以下特征：①岸线侵蚀后退速率逐年减弱,1855年之后的几十年岸线侵蚀速率可达几百米每年,目前已经降低为几米～几十米每年；②受岸堤及护岸工程等的影响,岸线后退基本得到控制,但水下岸坡却有侵蚀加剧的趋势,尤以15m以浅等深线向岸逼近最为明显,水下三角洲几乎已经被夷平；③不同岸段受地形、动力水沙条件不同,侵蚀特征略有差异,废黄河口-扁担港口岸段侵蚀最为严重,向南北两侧,侵蚀强度减弱。(3)6个固定断面监测结果表明：靠近废黄河口的SB3和SB4两个断面1989年之后水下岸坡后退速率较快；中山河口以西的断面起伏较大,具有明显的冲刷深槽,而中山河口以东的SB2断面水下岸坡则后退不明显,并且具有夏冲冬淤的特点；振东河口以南的SB5和SB6断面则表现出明显的上淤下冲特征。(4)GM(1,1)可以较为准确的预测废黄河三角洲中短期岸线演变。堤坝修正后,岸线预测精度得以提高。河口岸段以及近期发生溃堤的岸段,GM(1,1)预测精度较差。到2025年,废黄河三角洲将有近三分之一海岸的岸滩全部位于平均高潮线以下,亟需对原有堤坝进行加固或修建护岸工程。(5)海岸侵蚀脆弱性评估结果表明：①废黄河三角洲海岸整体脆弱性较高,高脆弱性主要分布在中山河口.新生港、黄河口尖附近及振东河口-扁担港口岸段；②泥沙来源断绝是废黄河三角洲较高脆弱性的根本原因,海平面上升引起的风暴潮频率增加、潮流和波浪增强使得海岸侵蚀加剧,人类活动如滩涂围垦、港口建设、堤坝修建等逐渐成为影响其海岸侵蚀脆弱性分布的主导。
[Abstract]:The Yellow River Delta in Northern Jiangsu is one of the most serious areas of the coastal erosion of China after the Yellow River is returned to the sea in the north of the Yellow River in the first 855 years. It can not only provide reference for the erosion protection of the coastal erosion of the Yellow River Delta, but also provide reference for the evolution law and the erosion protection of other deltas, especially the modern Yellow River Delta. Therefore, the research of the evolution of the waste Yellow River Delta has been a hot spot of the research on the erosion protection of the delta coast. On the basis of the assessment of the erosion vulnerability of the coastal erosion of the Yellow River Delta, the present situation of the erosion vulnerability of the different shore sections can be found, which can provide reference for the erosion protection of the coastal erosion of the Yellow River Delta, the development and utilization of the coastal resources and the management and management of the coastal zone. In this paper, the characteristics of the coastal evolution of the Yellow River Delta are studied by using the multi-phase remote sensing image, the chart data, the previous research results and the field measured data as the main data sources, combining the remote sensing (RS), the geographic information system (GIS) and the digital coast analysis system (DSAS). according to the characteristics of the study area, the two coastal dynamic factors, the shore beach slope, the underwater slope, the sedimentary dynamic environment, the three coastal morphological factors, the annual average sediment concentration, the annual mean high tide level and the two water power factors, and the coastal utilization type are selected according to the characteristics of the study area, Nine evaluation indexes, such as the two socio-economic factors of the suitability of the coastal development, were determined by using the analytic hierarchy process (AHP), and the evaluation system of the coastal erosion vulnerability was constructed. Finally, the vulnerability of the coastal erosion of the Yellow River Delta was assessed by the calculation of the coastal erosion vulnerability index (CVI). The results showed that: (1) The formation and evolution of the Yellow River Delta was mainly divided into five stages: the early stage of development, the slow development stage, the rapid development stage, the sandbank and the land-land adjustment period and the erosion-back period. (2) The evolution of the modern erosion of the waste Yellow River Delta has the following characteristics: the erosion rate of the erosion of the coastline of the Yellow River Delta has been reduced year by year, and the erosion rate of the shoreline for several decades after 1855 has been reduced to a few hundred meters a year, and it has been reduced to several meters to several tens of meters a year; it is affected by the bank and the bank protection works, etc. The reverse of the shoreline is basically controlled, but there is a tendency of the erosion of the underwater bank slope, especially 15 m, which is the most obvious in the shallow and deep line, and the underwater delta is almost completely flattened; the different shore sections are affected by the terrain and the dynamic water and sand conditions, and the erosion characteristics are slightly different. The erosion intensity of the waste yellow river mouth and the shore section of the flat-arm port is the most serious, and the erosion intensity is reduced to both sides of the north and south. (3) The results of the six fixed-section monitoring show that the backward velocity of the underwater bank slope is faster after the two sections of SB3 and SB4 close to the waste yellow river mouth, and the section of the west of the Zhongshan River mouth has a large fluctuation, and has obvious scouring deep groove. However, the SB5 and SB6 sections in the south of the Zhendong estuary show obvious upsiltation characteristics. (4) GM (1,1) can accurately predict the evolution of short-term shoreline in the waste Yellow River Delta. After the dam is revised, the prediction accuracy of the shoreline is improved. The prediction accuracy of GM (1,1) is poor in the river port and the recent bank segment. By 2025, the Yellow River Delta will have nearly one-third of the land on the coast below the average high tide line, and there is an urgent need to reinforce or build the revetment work for the original dam. (5) The assessment of the vulnerability of the coastal erosion shows that the overall vulnerability of the coast of the Yellow River Delta is high, and the high vulnerability is mainly distributed in the mouth of Zhongshan. It is the root cause of the higher vulnerability of the Yellow River Delta, the increase of the frequency of storm surge caused by sea level rise, the increase of the tidal current and the wave, the increase of the coastal erosion, the human activities such as the reclamation of the tidal flat, The construction of the port, the construction of the dam and so on gradually become the main factor in the distribution of the vulnerability of the coastal erosion.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P737.1

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