Deng, J. J.; Harff, J.; Li, Y. F., Zhao, Y., and Zhang, H., 2016. Morphodynamics at the coastal zone in the Laizhou Bay, Bohai Sea. Morphogenetic processes of the Yellow River Delta and the Laizhou Bay, Bohai Sea, China, have to be described by the interrelation of riverine sediment supply, relative sea level change and the effects of wind driven waves and nearshore currents. The research area is regarded a natural laboratory of the development of river dominated coastal zone with interfering natural and anthropogenic forcing factors. As well for the historical hindcast as for future projections of the morphogenetic coastal processes the Dynamic Equilibrium Shore Model (DESM) can be applied. This model generalizes the standard Bruun rule model and generates Digital Elevation Models (DEMs) scenarios on decadal to centennial time scales for the geological past and future. The basic concept is a dynamic equilibrium coastal profile evolution in adaption to the sediment budget in a spatially three-dimensional domain. By adding parameters to account for sediment mass contribution from riverine sediment flux, the DESM can be used to explore coastal morphological equilibrium states responding to sediment budget changes for river-dominated coastal zones. For the parameterization historical maps of the southern Bohai Sea have been applied to reconstruct paleo-coastlines for the 19^th century for the comparison with a modern DEM. Gauge measurements provided the data for an estimation of trends in sea level change for the Laizhou Bay on the decadal scale. Modern sea level rise together with reduced riverine sediment supply caused by anthropogenic activities such as damming up-streams may change the depositional environment at the Yellow River Delta and related areas of the Laizhou Bay from river dominated (progrational) to wave dominated (regressive) environment.

The Pearl River Estuary is in the geometric center of Guangdong-Hong Kong-Macao Greater Bay Area, which is one of the main battlefields to drive the high-quality development of China’s economy. This paper uses seven sets of typical satellite images in Pearl River Estuary for nearly half a century (from 1973 to 2021) to analyze the changes of coastline and sea reclamation. The results show that from 1973 to 2021, the total length of the coastline of the Pearl River Estuary increased from 240.09 km to 416.00 km, and that of the continental coastline from 186.87 km to 246.21 km (but the length of natural coastline in the continental coastline decreased from 136.91 km to 15.17 km). In the same period, the total reclamation area of the Pearl River Estuary increased by 28,256.06 ha. Before 2012, the growth rate of reclamation was generally fast. After 2012, the reclamation in China has entered a period of reflection. With reclamation was strictly controlled in the new era, only the previously approved reclamation projects and national major projects have been guaranteed, which makes the average annual growth rate of the coastline length and the reclamation area in the region show a significant downward trend. The reclamation in early days was largely for agriculture and pond culture purposes, but is shifting to transportation, industrial development, and urban construction in recent decades. This study scientifically analyzes the coastline and reclamation changes of the Pearl River Estuary in the past half century, which has a very important reference value for the next step to formulate marine ecological protection and restoration strategies, and construct a new pattern of marine space development and protection.