Hydrologic features, load of main pollutants and current condition of water quality in Lingdingyang Estuary are discussed by references and monitoring data. Affected by topography, runoff and tide, its dynamic conditi...Hydrologic features, load of main pollutants and current condition of water quality in Lingdingyang Estuary are discussed by references and monitoring data. Affected by topography, runoff and tide, its dynamic condition is very complicated. Different water areas have different hydrologic features. The topography under the water of Lingdingyang Estuary is higher in the northwest than that in the southeast. The shoal alternates with the deep trough within the bay .The distribution of the salinity and the contents of the mud and the main pollutants tally with the topography tendency. Change in water quality goes through four stages. Current condition of water quality is fairly good. Inorganic nitrogen is the primary pollutant, and then phosphorus. Rich in nutrition of nitrogen and phosphorus become a more and more prominent problem.展开更多
To satisfy the growing of land demand from economic development,a large scale of land reclamation from sea has been carried out in Inner Lingdingyang Bay in the Zhujiang(Pearl)River estuary in recent years.As a result...To satisfy the growing of land demand from economic development,a large scale of land reclamation from sea has been carried out in Inner Lingdingyang Bay in the Zhujiang(Pearl)River estuary in recent years.As a result,the tidal flat and the water channels became narrow,the frequency of floods increased,and the environment was un-dermined.Guangzhou Marine Geological Survey(GMGS)conducted an integrated project for marine geo-environ-ment and geo-hazards survey in 2003.With the integration of multi-temporal remote sensing images of 1977,1978,1988,1996,and 2003,GIS spatial analyzing approach and GPS technique,as well as field data and other background data of the region,this research investigated the comprehensive characteristics and the drivers of coastal land use dy-namics and shoreline changes in Inner Lingdingyang Bay.The results reveal that the reclaimed coastal land was mainly for agriculture and aquaculture in early years,but now they are used for construction sites of harbors and in-dustries,especially high-tech industry.展开更多
Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(L...Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(LE),located in the central and southern part of the Pearl River Delta,southern China with a long history of high-intensity anthropogenic disturbances,was studied to explore the contribution rate and mechanism underlying the alteration in hydrodynamics and sediment transport under each phase of human activity.A state-of-the-art modeling tool(TELEMAC-2D),was used to study the variations in the hydrodynamics and sediment transport,accounting for reclamation-induced shoreline and dredging-induced topography changes.The results indicated that:i)under the influence of successive land reclamation,the general distribution of the Confluence Hydrodynamic Zone(CHZ)in LE varied from scattered to concentrated,and these zones moved 3–5 km seaward.ii)Large-scale channel dredging weakened the residual flow in LE,decreasing the residual flow in the Inner-Lingding Estuary(ILE)by 62.45%.This was initiated by the enhancement of tidal dynamics through changes in the bottom friction caused by dredging in the ILE.In contrast,massive reclamation decreased the residual flow in the ILE by 17.55%and increased that in the Outer-Lingding Estuary(OLE).iii)Despite disturbances related to land reclamation and dredging,the estuarine jet flow in LE remained a turbulent jet system,and the estuarine jet flow became more asymmetrical.In addition,the position of the estuarine jet source moved 6–13 km seaward.iv)Both reclamation and dredging decreased the SSC in the ILE and increased the SSC in the OLE.Reclamation weakened the SSC in the ILE by 62.19%,whereas dredging enhanced the SSC in the OLE by 49%.Spatially,reclamation resulted in an increase in the SSC near the outlets and a decrease in the SSC in the northern portion of the Western Channel.Dredging mainly increased the SSC in the northern part of the OLE.v)The increase in the barotropic pressure gradient was the main factor driving the enhancement of the residual flow and SSC near the outlets.Moreover,the southward location of the“artificial outlets”favored the transport of suspended sediments to the OLE,which was one of the primary reasons for the increase in the SSC in the OLE.Finally,the tidal dynamics of the ILE intensified due to massive reclamation and dredging.The findings of this study indicate that hydrodynamics and sediment transport in LE have greatly changed over the last decades,with reclamation and dredging being the crucial drivers.The insights obtained from this study can serve as a reference for the comprehensive management of the Pearl River Estuary and other large estuaries experiencing similar anthropogenic forcing.展开更多
文摘Hydrologic features, load of main pollutants and current condition of water quality in Lingdingyang Estuary are discussed by references and monitoring data. Affected by topography, runoff and tide, its dynamic condition is very complicated. Different water areas have different hydrologic features. The topography under the water of Lingdingyang Estuary is higher in the northwest than that in the southeast. The shoal alternates with the deep trough within the bay .The distribution of the salinity and the contents of the mud and the main pollutants tally with the topography tendency. Change in water quality goes through four stages. Current condition of water quality is fairly good. Inorganic nitrogen is the primary pollutant, and then phosphorus. Rich in nutrition of nitrogen and phosphorus become a more and more prominent problem.
基金Under the auspices of China Geological Survey(CGS)(No.200311000006)
文摘To satisfy the growing of land demand from economic development,a large scale of land reclamation from sea has been carried out in Inner Lingdingyang Bay in the Zhujiang(Pearl)River estuary in recent years.As a result,the tidal flat and the water channels became narrow,the frequency of floods increased,and the environment was un-dermined.Guangzhou Marine Geological Survey(GMGS)conducted an integrated project for marine geo-environ-ment and geo-hazards survey in 2003.With the integration of multi-temporal remote sensing images of 1977,1978,1988,1996,and 2003,GIS spatial analyzing approach and GPS technique,as well as field data and other background data of the region,this research investigated the comprehensive characteristics and the drivers of coastal land use dy-namics and shoreline changes in Inner Lingdingyang Bay.The results reveal that the reclaimed coastal land was mainly for agriculture and aquaculture in early years,but now they are used for construction sites of harbors and in-dustries,especially high-tech industry.
基金funded by the National Natural Science Foundation of China(Grant Nos.42201104,41376101,and 42071123)China Postdoctoral Research Foundation(Grant No.2023M730758)Guangdong Provincial Special Key Project of Six Marine Industries in 2022“Research on Three-dimensional Efficient Utilization of Marine Spatial Resources in Guangdong-Hong Kong-Macao Greater Bay Area”([2022]49).
文摘Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(LE),located in the central and southern part of the Pearl River Delta,southern China with a long history of high-intensity anthropogenic disturbances,was studied to explore the contribution rate and mechanism underlying the alteration in hydrodynamics and sediment transport under each phase of human activity.A state-of-the-art modeling tool(TELEMAC-2D),was used to study the variations in the hydrodynamics and sediment transport,accounting for reclamation-induced shoreline and dredging-induced topography changes.The results indicated that:i)under the influence of successive land reclamation,the general distribution of the Confluence Hydrodynamic Zone(CHZ)in LE varied from scattered to concentrated,and these zones moved 3–5 km seaward.ii)Large-scale channel dredging weakened the residual flow in LE,decreasing the residual flow in the Inner-Lingding Estuary(ILE)by 62.45%.This was initiated by the enhancement of tidal dynamics through changes in the bottom friction caused by dredging in the ILE.In contrast,massive reclamation decreased the residual flow in the ILE by 17.55%and increased that in the Outer-Lingding Estuary(OLE).iii)Despite disturbances related to land reclamation and dredging,the estuarine jet flow in LE remained a turbulent jet system,and the estuarine jet flow became more asymmetrical.In addition,the position of the estuarine jet source moved 6–13 km seaward.iv)Both reclamation and dredging decreased the SSC in the ILE and increased the SSC in the OLE.Reclamation weakened the SSC in the ILE by 62.19%,whereas dredging enhanced the SSC in the OLE by 49%.Spatially,reclamation resulted in an increase in the SSC near the outlets and a decrease in the SSC in the northern portion of the Western Channel.Dredging mainly increased the SSC in the northern part of the OLE.v)The increase in the barotropic pressure gradient was the main factor driving the enhancement of the residual flow and SSC near the outlets.Moreover,the southward location of the“artificial outlets”favored the transport of suspended sediments to the OLE,which was one of the primary reasons for the increase in the SSC in the OLE.Finally,the tidal dynamics of the ILE intensified due to massive reclamation and dredging.The findings of this study indicate that hydrodynamics and sediment transport in LE have greatly changed over the last decades,with reclamation and dredging being the crucial drivers.The insights obtained from this study can serve as a reference for the comprehensive management of the Pearl River Estuary and other large estuaries experiencing similar anthropogenic forcing.
