Monitoring coastal reclamation changes across Jiangsu Province during 1984–2019 using landsat data

Abstract

Owing to sufficient sediment from the abandoned Yellow River and the Yangtze River, large scale tidal flats have been developed along the Jiangsu coast. To obtain more space for urban expansion, economic growth and food security, many coastal reclamation projects have been conducted around the Jiangsu tidal flats in recent years. Coastal reclamation in Jiangsu dramatically altered the environment and ecosystem in coastal zones. Hence, detailed information on coastal reclamation is urgently required for better implementation of sustainable coastal planning and management. In this study, we adopted Landsat series images to monitor the temporal changes of coastal reclamation across Jiangsu Province from 1984 to 2019. First, we integrated water index, edge detection and visual interpretation to obtain artifical shorelines over different years from Landsat data. Then, these multi-year shorelines were stacked to extract coastal reclamation area over different periods. Finally, we analyzed the spatial-temporal pattern and types of coastal reclamation in Jiangsu. The total amount of coastal reclamation area in Jiangsu has reached 16.61 × 104hm2 since 1984. Across Jiangsu Province, Yancheng had the largest amount of coastal reclamation of 10.11 × 104hm2, accounting for 61% of the total coastal reclamation area, and the areas of coastal reclamation in Nantong and Lianyungang were 5.42 × 104hm2 (33%) and 1.07 × 104hm2 (6%), respectively. After 1993, coastal reclamation in Jiangsu grew rapidly, with the highest growth rate of 0.65 × 104hm2 per year over 1993–2011. During 1984–2019, water body, which was the major coastal reclamation type, decreased by 16.65%, while construction and agricultural land increased by 18.98% and 5.29%. Moreover, the proportion of unused land decreased by 7.48%, and still accounted for 21.87% of the total reclamation area. This study demonstrated the availability of remote sensing data in large-scale coastal zone monitoring and assessed the temporal changes of coastal reclamation across Jiangsu Province during 1984–2019, which can deepen our understanding of the impact of coastal reclamation on landscape changes along the Jiangsu coast. In the future, the utilization rate of coastal reclamation needs to be improved and the benefit and the negative effect from coastal reclamation should be balanced to promote the sustainable development of tidal flat resources in Jiangsu Province.