摘要
崇明岛作为我国最大的河口冲积岛,其形成发育与长江来水来沙息息相关。历史上就有崇明岛围垦筑堤的记载,近60年来崇明岛东部地区所筑大堤主要有54大堤、64大堤、68大堤、92大堤和98大堤。选取正东、东北、东南不同方向的4个断面,以大堤位置代表所筑年份海岸线位置,对崇明岛东部淤涨速率及滩地淤涨面积变化进行计算,结果表明:(1)近60年来崇明岛东部整体淤涨速率约为200 m/a,淤涨面积年均增长率为2.80 km^2/a;(2)不同断面上淤涨速率存在差别,其中正东方向断面上淤涨最快;(3)不同时段崇明岛东部各断面淤涨速率存在快慢变化。各断面上,20世纪90年代的淤涨速率均最大。对比发现,20世纪50~80年代崇明岛东部淤涨速率的变化趋势,与同期长江年入海泥沙量的变化趋势基本一致;但20世纪90年代,由于围垦强度加大,两者变化趋势不一致。以海堤研究岸线变迁的工作尚不多见,此方法将为研究长时间尺度的岸线变迁提供借鉴。
Chongming Island is the largest estuary alluvial island in China. Its formation and development relate closely with the fluxes of water and sediment from the Yangtze River. There are records of reclamation or embankment in the Chongming Island in history. According to main seawalls constructed in the eastern part of Chongming Island during the last 60 years, the progradation rates along four transects in northeast, east and southeast directions respectively, and siltation area between seawalls of the eastern part of Chongming Island are calculated. The results showed that： （1） in the last 60 years, the progradation rate of the eastern part of Chongming Island was about 200 m/yr, and the average annual increasing rate of siltation area was 2.80 km2/a; （2） there were differences between the different transects in terms ofprogradation rate, and the progradation rate in the east was faster than that along every other transect; （3） there were differences in progradation rate for each transect in different time spans. Of all transects, the progradation rate in the 1990s was greater than those in other time spans. The trend of progradation of the eastern part of Chongming Island was coincident with that of variation of the annual sediment discharge from the Yangtze River from the 1950s to the 1980s. There was a difference between both trends for the heavy reclamation period in the 1990s. It is still rare to study the shoreline changes through the seawall. The method can provide a reference for studying the shoreline changes in long time scale.
出处
《长江流域资源与环境》
CAS
CSSCI
CSCD
北大核心
2017年第5期698-705,共8页
Resources and Environment in the Yangtze Basin
基金
国家自然科学基金项目(41471161)~~
关键词
崇明岛东部
大堤
淤涨速率
长江水沙
围垦
the eastern part of Chongming Island
seawall
the progradation rate
fluxes of water and sediment from the Yangtze River
reclamation
