长江口崇明东滩冲淤演变分析

THE ANALYSIS OF THE EASTERN CHONGMING TIDAL FLAT'S EVOLUTION IN THE YANGTZE RIVER ESTUARY

通过对崇明东滩水文、泥沙、地形等资料的分析，阐述1983--2003年崇明东滩冲淤演变过程。1．1983--2001年，崇明东滩淤涨延伸较快，Om以上各等高线大幅度向外扩展，沿正东向年均外移228～279m不等。潮滩面积稳定增长，3．5m以上面积增加最多，达65．2km^2，Om以上面积共增加8．4km^2。滩面淤高迅速，尤其是高潮滩，且有随高程的降低，淤高速率下降的趋势。2．2003年与2001年相比，崇明东滩Om以上面积增加4．2km^2，2．Om以上面积减少0．8km^2，3．Om以上面积年均增长率下降。3．人类活动（如围垦）对崇明东滩的演变产生重要影响。流域来沙量大幅减少对潮滩演变的影响有待于进一步研究。

The eastern Chongming tidal flat is one of the main tidal flats of the Yangtze River estuary. Supported by Mapinfo7.0, 3 pieces of the Yangtze Estuary from 1983 to 2003 are digitized and so that the area, the thickness of erosion-accretion and bathymetric contour progradation rate are calculated. Based on measured and collected data of topography from 1983 to 2003 ,sediment and hydrodynamics, the analysis of this area can give us some con- clusions： 1During 1983 to 2001 the eastern Chongming tidal flat deposited and extended con- siderably,and the area of the tidal flat above 3.5m had increased from 33.6km^2 to 98.8km^2. 2 An increase of the tidal flat above 0m in area was 4.2km^2, but there was a decrease of 0. 8km^2 in area of the tidal flat above 2.0m and a decline in the average annual deposition rate of the tidal flat above 3.0m. 3 Human＇s activities have an important effect on the development of the eastern Chongming tidal flat.