Land-Use Changes and Human Driving in and Near the Yangtze River Delta from 1995–2015

We analyzed the characteristics and trends of land-use change in and near the coastal zone of the Yangtze River Delta(YRD) during five periods(1995, 2000 2005, 2010, and 2015) using remotely sensed Landsat imagery. Using automatic supervised classification combined with visual interpretation, we obtained land-use information for five study areas(Nantong, Shanghai, Jiaxing, Ningbo, and Zhoushan). Significant land-use changes have occurred in this area between 1995 and 2015, characterized in particular by large reductions in cultivated land and rapid increases in urbanized land. In addition, land reclamation was very active in this period as an effective supplement to the increased demand for land development: since 1995, 1622 km^2 of land was reclaimed from near-coastal regions in the study area. This increase in urbanization was jointly driven by population, economic, transportation, and policy factors. Urban areas expanded from the center outward in concentric rings, with infrastructure guiding the radial expansion of development along transportation corridors, thus forming a network of connections. Due to the influence of national land regulation policies, the expansion rate of development in the YRD gradually diminished after 2010. This indicates that the area's resource and environmental carrying capacity has reached a saturation stage in which urbanization has transitioned from broad and incremental expansion to the intensive use of land resources.

Introduction to the China-Vietnam Cooperation Project: A Comparative Study of the Holocene Sedimentary Evolution of the Yangtze and Red River Deltas

Both China and Vietnam confront the challenges of natural geohazards and environmental changes in their deltas and coastal zones due to rapid urbanization, economic development, and the impacts of global climate change. China and Vietnam initiated a comparative study of the Holocene sedimentary evolution of the Yangtze River Delta(YRD) and Red River Delta(RRD) for the period 2015–2018 in order to improve the understanding of the two delta evolution histories in the Holocene. Previous investigative data of the two rivers, onshore delta plains, and offshore subaqueous deltas have been explored and reinterpreted. New data gleaned from boreholes, piston cores, shallow seismic and hydrodynamic sources have been collected from the offshore YRD and the East China Sea inner shelf, and surface sediments and short cores have been collected from the RRD near-shore areas. Six focal areas of the joint project have been defined for comparative studies of the two deltas, including morphological development, sequential stratigraphy, coastline shifting, sedimentary characteristics, sedimentary dynamics, and correlation with anthropogenic global climate change. The results of these study areas are presented herein. The joint project also includes cooperative capacity building; exchanges of young scientists have been organized during the project period, and hands-on training in laboratory geochemical analysis, numerical modeling, and seismic data processing and interpretation have been provided by China and its Vietnamese geoscientist partners. Joint field excursions were organized to the upstream of the Yangtze and Red Rivers in Yunan Province, China, all the way downstream along the Vietnamese portion of the Red River. These joint studies have, over the past three years, improved understanding of the evolutionary history of these two major rivers and their mechanisms of source to sink. Joint project results of these two major deltas are not limited to the geosciences; the cooperative mechanical and operational experiences have been helpful for future cooperation in the field of marine geoscience between China and Vietnam, as well for cooperative activities with other ASEAN member countries.