崇明东滩地貌演变对生态治理工程的响应研究

Study on the response of morphological evolution of Eastern Chongming Shoal to ecological management project

2013-2014年长江河口崇明东滩实施生态治理工程,围垦面积达14.4km^2。基于地面三维激光扫描技术(TLS),对治理工程前后崇明东滩地貌进行跟踪观测。研究发现崇明东滩北、中、南三部分对治理工程响应具有显著差异,可以看到自北至南的逐步响应过程。崇明东滩北部潮沟体系均发生改变,光滩淤积强度为+19.5cm/a,+2m线向海推进速率为356m/a,该区域原有地形、地貌均被改变,并逐步向新的动态平衡调整;中部区域部分潮沟体系发生改变,光滩淤积强度达+59cm/a,+2m线向海推进速率为251m/a,该区域部分地形、地貌发生改变,正在逐步调整过程中;南部潮沟体系格局基本稳定,但仍在缓慢发展中,光滩冲刷强度为-3.6cm/a,+2m线向海推进速率为3.9m/a,该区域目前还未受到治理工程的显著影响,地貌演变仍处于动态平衡中。

Ecological management project was implemented in Eastern Chongming Shoal,with an area of 14. 4km2,during 2013- 2014. Using the Terrestrial Laser Scanner（ TSL）,the morphological variations of the Eastern Chongming Shoal were investigated before and after the project. Result shows that the responses of different regions to the project are obviously different,which gradually decrease from north to south. The tidal creek in the north area of the Eastern Chongming Shoal significantly changes. The deposition intensity of bare flat areais 19. 5cm / a,while the ＋ 2m contours moves towards sea with a rate of 356 m / a. The equilibrium of the north area has been disturbed and will form a new one in the future. The tidal creek in the middle area of the Eastern Chongming Shoal also alters. The deposition intensity of bare flat is 59 cm / a and the ＋ 2m contours has a seaward change rate of 251 m / a. The morphology of the middle part partly changes and adjusts.However,the south area of the Eastern Chongming Shoal remains stable. Erosion intensity of bare flat is only3. 6cm / a and the ＋ 2m contours have a change rate of 251 cm / a towards sea. The influenc in south area of the Eastern Chongming Shoal is not obvious by the project due to the reed. The tidal flat in the south area could still keep balance.