Impact of anthropogenic activities on morphological and deposition flux changes in the Pearl River Estuary, China

Abstract

The evolution of the Pearl River Estuary (PRE), China in recent decades has been dominated by human activities. Historical admiralty charts and remote sensing images indicated that from 1936 to 2017, the tidal flat area and water area decreased by 23.6 × 107 m2 and 60.7 × 107 m2, respectively. The average advancing rate of the coastline of the PRE to the sea from 1972 to 2017 reached approximately 64.8 m/year, which is several times or even dozens of times that since the mid-Holocene. Land reclamation was the main reason for the dramatic changes in the water area and coastline. Although the water volume of the PRE showed a decreasing trend from 1936 to 2017, the water volume reduction rates for 1996–2005 and 2005–2017 were only 29% (1.27 × 107 m3/year) and 12% (0.53 × 107 m3/year), respectively, of that for 1936–1972. The combined influences of channel dredging, sand mining, and sediment load reduction caused by dam construction have contributed to this change. From the perspective of the filling up of the estuary, channel dredging, sand mining, and dam construction in the river basin are beneficial for prolonging the life of the estuary.

Asymmetric evolution of river mouth bifurcation under angled river‐tide interaction, a case study at river mouths of Lingding Bay, Pearl River estuary

“…Human activities such as dam construction have caused the supply of river sediment to decrease significantly since the 1990s (Chu et al, 2009). Therefore, the depositional rate also decreased in the Pearl River Estuary (Wei, Cai, & Zhan, 2021; Wu, Saito, et al, 2016). The reduced sediment supply from the catchment only affected the magnitude of the sediment flux and deposition rate, not flow dynamics (Figure 12).…”

“…The reduced sediment supply from the catchment only affected the magnitude of the sediment flux and deposition rate, not flow dynamics (Figure 12). Other human activities, such as channel dredging and sand mining, can increase tidal discharge in low‐angle channels (Wei, Cai, & Zhan, 2021). These human effects on channel evolution are less significant than those on land reclamation activities.…”

“…Recently, the government restricted land reclamation activities (Zhang et al, 2022). Since the 2010s, an increase in tidal range has been observed at the river mouths of Lingding Bay (Wei, Cai, & Zhan, 2021; Yang et al, 2019). If channel dredging in low‐angle channels and sea level rise continues, a continuous increase in the tidal prism will induce the degradation of the secondary (lateral) channel.…”

Stimulated Raman Scattering Microscopy Reveals Bioaccumulation of Small Microplastics in Protozoa from Natural Waters

“…Lake Taihu was chosen because it is the third largest freshwater lake in China and the sampling site is in Meiliang Bay, which is the one of the most polluted area in Lake Taihu . The coastal water was collected from the Pearl River Estuary, which is one of China’s largest estuaries with strong anthropogenic impacts . For this purpose, a cone-shaped plankton net (mesh size of 65 μm) with a collecting vessel at the narrow end was used to collect protozoa from the surface water (0.1–0.5 m below the surface) following a procedure similar to that recommended by the US EPA .…”

Economic Development Drives Massive Global Estuarine Loss in the Anthropocene

“…We note that estuarine dams and land reclamation are not the only human activities within an estuary but rather are part of a wide spectrum of disturbances such as sand mining, dredging, deforestation, accelerated subsidence, etc. (e.g., Nienhuis et al., 2020; Koehnken et al., 2020; Wei, Cai, & Zhan, 2021; Wei, Cai, Zhan, & Li, 2021; Syvitski et al., 2022a, 2022b). Unfortunately, these human activities are not readily measurable from aerial imagery and are therefore not included in this study.…”