【作者】 马妍妍；

【导师】 李广雪；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2008， 博士

【摘要】 本文以1987年、1996年、2001年和2006年LandsatTM遥感卫星资料为基础,提取这四个时期黄河三角洲土地利用变化情况,1987年到2006年黄河三角洲高潮线以上面积增加了365km2,低潮线以上增加31km2。黄河三角洲的区域土地利用变化速度(0.96%)较大;土地利用程度(257)低于高度发达地区水平(275),有较大的发展潜力。自然状态下的土地利用类型大幅度减少,人工控制的土地利用类型大幅度增加。虽然黄河三角洲有较大的开发潜力,但是它是一块新生的陆地具有生态环境脆弱的特点,黄河三角洲开发一定要建立在科学的土地适宜性评价基础上,减少盲日开发造成的恶果。以1976~2006年之间9个时期的Landsat卫星遥感资料为基础,提取潮间带信息,研究潮间带的变化趋势。在研究期内,海岸线(低潮线)侵蚀的区域发生孤东以北和清水沟流路南侧的区域。钓口流路附近海岸侵蚀最剧烈,海岸线平均后退5.7km(Ⅱ区),最大后退距离为12km;三角洲南部海岸为缓慢侵蚀状态,平均蚀退距离为1.4km。清水沟流路海岸平均淤进距离为15.1km,最大距离为18.3km。过去的30年,低潮线以上面积减少192km2。另外1985年以后黄河三角洲东北部逐渐被人工护岸大坝包围,海岸线稳定,高低潮线重合。滩涂变化受人类活动影响较大,总面积呈减少的趋势。钓口流路西侧在人工控制下高潮线不退反近,潮滩平均宽度减少6.8km,面积减小160km2;三角洲东北部一直到孤东油田一带,海岸基本被人工护岸大坝包围,滩涂几乎全部消失;现行河口处,高潮线在人工控制下随河口一起向外推进,滩涂分布在河口两侧,面积变化不明显;三角洲南部高潮线在人工控制下向海推进为主,滩涂面积减小。以1968年到1999年水深数据为基础研究黄河三角洲水下岸坡演化规律,钓口流路西侧浅水侵蚀深水淤积,冲淤变化缓慢;钓口流路附近,浅水侵蚀深水淤积,冲淤转折深度在11~12m;神仙沟流路附近水下岸坡变化北部跟钓口流路接近,南部受现行河口影响出现较大幅度的淤积;现行河口处主要是12~14m以浅区域快速向海淤进,下部变化幅度不大;三角洲南部近岸浅水区变化较小,深水区缓慢淤积。黄河三角洲海域沉积物以粉砂为主,颗粒粘结性不大,黄河三角洲的岸坡调整符合Komar提出的均衡剖面理论。本文综合不同阶段近岸水下地形的演化特征,推导模拟三角洲海岸均衡剖面演化模式,模拟结果表明:河口废弃约150年以后,三角洲地貌特征基本不存在,从粉砂质海岸转变为粉砂淤泥质。利用公式计算得到埕岛海域护岸大坝位置不同时段的水深,得到堤前最大冲刷冲刷深度范围(7~9m),符合有关堤前最大冲刷深度的预测。本文选择调水调沙试验期两年完整的周期,研究调水调沙对三角洲海岸演化的影响,结果表明,调水调沙试验的主要影响范围主要集中在口门附近的小范围内,对三角洲海岸的整体冲淤演化影响不大。另外每年的调水调沙集中下泄水沙,海洋动力单方面作用时间加长,使得造陆速率降低。在2007年第六次调水调沙期间,研究了4000m3/s的大流量对黄河分流河道的影响。研究结果表明,洪峰冲刷河道,主槽的面积和平均深度达到调水调沙前的2倍。调水调沙结束后,河槽又很快淤积,河相关系恢复到调水调沙前状态,略有改善。距河口15 km的C2断面受到海洋的影响,大冲大淤的特点更为突出。在行洪期间提取150m3/s流量向湿地引水,既能保证湿地淡水的存储和更新,又不会影响到主槽行洪。更多还原

【Abstract】 Get land use information from the remote sensing images of 1987, 1996, 2001 and 2006.In research period the area landward of high title line increase by 365km2.Land use changed in a fast speed(0.96%) and development degree is low. The area of land use types which is reformed by human increase and area under nature conditions decrease.Get tidal flat information from nine years remote images between 1976 and 2006. In the past 30 years, rapid erosion occurred in the area north to Gudong, and the coastline retreat 5.7km near Diaokou estuary and the largest retreat distance of this area is 12km.In the south part of Yellow River delta coastline retreat slowly. Near the Qingshuigou estuary coastline silting-up quickly and in the past 30 years coastline silting-up 15.1km.In the north-east part of the delta sea wall has been built to protect the coastline, and in the area high and low tidal line coincide, and tidal flat disappear.The changes of tidal flat is controlled by low and high tidal line, and the high tidal line is mainly controlled by human activities. In the north part of Yellow River delta high tidal line moved seaward because of reclamation, and the area of tidal flat decreased. In the area where coastline is protected by sea wall the tidal flat disappeared. The tidal flat near the new estuary area changed little and in the south part of the delta decreased because high tidal line moved seaward.Study the evolution trend of the under water slope with the water depth data between 1968 and 1999, in the north-west and south part of Yellow River delta under water slope deposit slowly. And near Diaokou estuary erosion occurred in the shallow water and sedimentation in deep water, and the transition zone is near the water depth of 12m. Near the Qingshuigou estuary deposit quickly in shallow water (less than 12~14m).Synthesizing evolvement character of offshore subaqueous terrain of different stages, we deduce the simulating formula of Yellow River Delta subaqueous slope evolution trend. Validate result shows that simulated results are accordant with evolvement trend of Yellow River Delta. The deduced result from the formula indicates that after 150 year since the estuary was abandoned, the shape of the under water delta disappear, and coast type changed from mealy sand to silty mud coast. The utmost scour depth scope in front of the sea wall calculated according to formula is 7-9m in Chengdao area, which is agreement with the prediction of maximum scour depth in front of sea wall.Study the effect of water and sediment regulation test on the coast evolvement during 2002.7-2004.7. The results indicated that siltation center whose maximum thickness excesses 10m, formed at the 2m water depth in the estuary. The deposition body mainly distributed in the mouth bar area, and water and sediment regulation test has little effect on the whole coast of Yellow River delta. And study the effect of large flow on the distributary channel. Results shows that flood is able enlarge the area of main channel and depth of the river. And then after the flood the main channel reinstate. And the study result also shows that we can shunt 150 m3/s flow to wetland area, it has no adverse effect on river channel degradation.更多还原