| Coastal zone, which is at the junction of land and sea, is the transition zone of the land system and marine system. The shoreline shows the degree of the interaction between the land and sea. Generally, the shoreline keeps moving forward to the sea as time passes by. However, nowadays, since the coastal areas are densely populated, the land cannot meet the increasing demand of various human activities. People begin to intervene the morphology evolution of the shoreline. Therefore, the evolution of the shape of the shoreline can be used as an indicator of how deeply human activities have influenced the natural environment of the coastal zone. Meanwhile, as a measure of shoreline morphology, the shoreline fractal dimension has been successfully applied to the study of shoreline evolution. Thus, studying the associations between the shoreline morphology evolution and human activities will be of good use to improve the evaluation of coastal landscape pattern. This paper studies the east coastal areas in Zhejiang. The areas were divided into four segments from north to south:namely, the Xiangshan Bay coast segment, the Sanmen Bay coast segment, the Taizhou Bay cost segment and the Yueqing Bay coast segment. RS and GIS are used to study the relationship between the shoreline shape evolution and human activities in Zhejiang. Information of Bay shoreline between 1991 to 2014 are extracted to study the spatial and temporal changes in shoreline morphology, and shoreline fractal dimension as well as the shoreline morphological changes caused by reclamation. The results are shown as below:(1) The overall length of the Zhejiang Province east shoreline is decreasing. From 1991 to 2014, the shoreline of the research areas reduced by 39.6km in total. As for the four coast segments involved in the research, the Yueqing Bay shoreline decreased by 42km, the Sanmen Bay shoreline reduced by 3.5km, the Taizhou Bay shoreline increased by9.5km, and the Xiangshan Bay shoreline decreased by3.6 km. From 199 to2014,the overall change intensity of the shoreline segments involved and the individual change intensity of the Yueqing, Sanmen, Taizhou, and Xiangshan Bay shortline are-0.15%-0.87%,0.05%,0.23%, and -0.06%. The shoreline of the four bays changed in a descending order, which is:the Yueqing Bay coasts> Taizhou Bay coasts> Xiangshan Bay coasts> Sanmen Bay coasts. Thetortuosity of each segment was declining, among which, the Taizhou Bay coasts and the Sanmen Bay coasts showed the most significant declining trends. Due to the increasing building of the artificial shoreline, the retention rate of the natural shoreline decreased. The shoreline tended to be more and more straight.(2) The results of the fractal dimension of the four bays are in the following order:the Yueqing Bay coasts> the Sanmen Bay coasts> the Taizhou Bay coasts> the Xiangshan Bay coasts. From 1991to2014, the fractal dimension of the Yueqing Bay Coast segment dropped from 1.0917 to 1.0702, which changed consistently with the shoreline. The fractal dimension of Taizhou Bay Coast increased from 1.0474 to 1.0756 and the fractal dimension of the Sanmen Bay Coast shoreline dropped from 1.0773 down to 1.0688, while its shoreline increased by 0.05%. The Xiangshan Bay Coast’s fractal dimension increased first and then decreased, which was consistent with its shoreline changes.(3) By analyzing the reclamation and shoreline changes, the reclamation in the coastal areas in Zhejiang can be divided into three types, namely, atrophy, growth-oriented and stable. Atrophy reclamation lead to the straightening of shoreline, the decrease of the shoreline length, and the shoreline fractal dimension; as for the stable type, reclamation is carried out in the artificial shoreline, and the changes of shoreline length and shoreline fractal dimension are marginal; the growth-oriented reclamation will cause the shoreline to extend to the sea, the increase in the shoreline length and the fractal dimension. |
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