渤海湾天津滨海新区围海造陆前后海底冲淤变化

Changes of seabed erosion and siltation after the land reclamation in Tianjin Binhai New Area coast of Bohai Bay

天津滨海新区2009—2010年实施了共计超过420 km;的围海造陆工程围堤建设,必然对该区的流场和侵蚀淤积产生影响。本文以2006—2009年海底地形地貌为本底,对比分析2015年海底地形地貌实测水深与浅地层剖面数据,结果显示,围海造陆外围海底冲淤与海底地形发生显著调整,呈现出北部淤积南部侵蚀的整体格局。淤积区主要分布于天津港航道防波堤以北、临港产业区,以及南港工业区南侧海域,淤积厚度可达0.9~1.3 m。侵蚀区主要分布于临港经济区至南港产业区东部的大片海域,北疆电厂东侧,以及中心渔港海挡豁口处,侵蚀量达0.4~2.0 m。原本平坦的海底在冲淤再平衡作用下,形成明显地形起伏。海底淤积区域的海底坡降显著增加,并接近强物源供给背景的河口坡降值。而侵蚀区海底被强烈冲刷改造至近乎水平。

In 2010, in order to implement the national development strategy, Tianjin Binhai New Area implemented a land reclamation project with a total area of more than 420 square kilometers, and the peripheral boundary was basically completed in that year. Taken the seabed topography from 2006 to 2009 as the background, this paper compares and analyzes the seabed data of water depth and sub-bottom profile in 2015, and finds that the seabed erosion and siltation in the periphery of land reclamation have been significantly adjusted,showing an overall pattern of siltation in the north and erosion in the south. The silting area is mainly distributed in the north coast of the breakwater of Tianjin Port, the south coast of Nangang Industrial Zone, and the Inner corner of Lingang industrial zone. These silting thickness reach 0.9~1.3 m. Erosion areas are mainly distributed in east coast form Lingang Economic Zone to Nangang Industrial Zone, the east coast of Beijiang Power Plant,and round the reclamation gap of the Central Fishing Port, with erosion amount of 0.4~2.0 m. Under the action of erosion and siltation rebalancing, the originally flat seabed developed obvious topographic relief. The seabed slope in the siltation area increases significantly, and is close to the estuary slope value under the background of strong provenance supply. However, the seabed in erosion area was strongly washed and transformed to a near level.