基于海底地形地貌及浅地层剖面调查的倾倒区监测技术评价研究

本文以大连南海域三类疏浚物海洋倾倒区为例，对倾倒区海底地形地貌及浅地层调查技术中的单/多波束测深、侧扫声呐海底探测和声学浅地层剖面调查技术进行了评价。结果显示，倾倒使得海底地形发生明显变化，且相比单波束测深，多波束测深更能准确获取海底地形特征，推荐使用；由于倾倒造成微地貌与底质组成变化，侧扫声呐海底探测能明确识别出倾倒物质分布区域；而由于倾倒物质为与该海域沉积物组成差异不大的疏浚物，且近年倾倒量微小，声学浅地层剖面调查无法辨识倾倒物内部的期次分层，在该类倾倒区的监测中意义并不突出。

Assessment of the ocean dumping sites monitoring methods based on submarine topography,geomorphology survey and sub-bottom profiling

Among the current instructions and criterions for ocean dumping sites mornitoring in China, the ones based on chemical and biological variations are relatively mature; however, little comparison and specifying have done upon the submarine topography, geomorphology, and sub-bottom profiles, As a result, the movement and evolvement of the dumped materials cannot be fully tracked, which restricts the improvement of the monitoring work in China. In this study, we took the ocean dumping site for the third class dredged-materials south off Dalian as an example, estimated the advantages and disadvantages of single beam/multibeam bathymetry, sidescan sonar seafloor imaging, and sub-bottom profiling. It turns out that, the dumping activities significantly changed the submarine topography, which could be more accurately revealed by multibean rather than single beam echo sounding. Thus the multibeam bathymetry is worth of recommending in the monitoring work. Further, the seabed geomorphology and sediment characteristics become different after dumping, helping in recognizing the dumping area, which is useful in the dumping site monitoring. Meanwhile, due to little difference between the dredged materials dumped and the local sediment, and small amount of dumping recent years in this site, it failed to distinguish the inside layers from different dumping events by sub-bottom profiling. That means, the sub-bottom profiling is helpless in monitoring such dredged material dumping sites.