| The area of the tidal flat of Jiangsu Province ranks top in the courtry, and approximately accounting for1/4of the total area of the country. It is considered as a largest potential land resource of China at present and in a long future, and of great importance for socio-economic development of Jiangsu coastal area. As a result, study of dynamic evolution feature and regularity of the tidal flat resource, is of strategic importance for sustainable development of Jiangsu coastal tidal flat development.The rates of coastline change in different historical stages of Jiangsu coast are estimat-ed according to historical coastline locations since the New Stone Age.4satellite remote sensing images (1980MSS,1992TM,2007SPOT-5,2011CBERS-02) are used to extract coastline locations since1980’s by visual interpreting And two submarine topographical maps of Jiangsu Coast masured in1979and2008are used for vector quantization of the isobathes of0m,2m,5m,10m by the technology of GIS. And the areas from the coastline to different isobaths of1979and2008are calculated respectively. On the basis of above works, The Spatio-temporal characteristics and evolution of coastline and tide flat resources, and the driving forces are studied. The results are shown as follows.1. The Jiangsu coastline shows a progradation trend since the new Stone Age, with a rate of about11m/a in average. The coastline kept fundamentally stable before the year of1128ADand reached the fastest speed of about86m/a during the Huanghe River flow into the Yellow Sea through Jiangsu coast. The coastline of the abandoned Huanghe River Delta eroded after the lower reach of Huanghe River shift back to Bohai Sea, however the coast to the south of the delta remained prograding, and the erosion stretch extended southward gradually.2. Due to long-term reclamation of tidal flat, most of the Jiangsu coastline has already became artificial seawall, with obvious changes in stagesand different segments. The coastline of of Jiangsu coast advanced with a rate of about30.42m/a in average from1980to2011. The rate is about67.90m/a from2007to2011,33.07m/a from1992to2007and14.62m/a from1980to1992, On the middle segment (from Biandanhe River Mouth to Tuanjiegang), the south segment (from Tuanjiegang to Lianxinggang) and the north segment (from Xiuzhenhe River Mouth to Biandanhe River Mouth), the coastline advanced at rates of95.68m/a,34.62m/a and10.61m/a in average respectively in the past three decades.3. From1979to2008, the isobath of0m of Jiangsu Coast (the radiate sand ridges are not included) were mainly retreat to the land with an average distance of about716.84m, and tidal flat of about361.41km2losed, due to decrease of sediment supply source and enhancement of tide and wave action. Only the segments from Xisu to Shaoxianghe River Mouth and for Xinbeilinzha to Beikan prograde during this period, due to building of the Xidadi bank and shelter of the radiate sand ridges respectively. Xisu-ShaoXiang and Beiling-Beikan silt forward to the sea slowly for the construction of Xi Dadi and the protect of Radiation sandbars.4. For the change of tide flat resource, the tidal flat resource of Jiangsu Coast shows a decreasing tendency since1980’s. In terms of driving forces, tidal flat reclamation forced coastline advancing, and natural coastal erosion caused retreat of the isobaths, are the primary reasons of tidal flat resource shrinkage. |
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