Using satellite images taken on different dates,GIS analysis of aerial photos,bathymetric maps and other field survey data,tidal troughs and major sand ridges in the northern Jiangsu coastal area were contrasted.The r...Using satellite images taken on different dates,GIS analysis of aerial photos,bathymetric maps and other field survey data,tidal troughs and major sand ridges in the northern Jiangsu coastal area were contrasted.The results show that there have been three types of movement or migration of tidal trough in this area:(1) Periodic and restricted,this type of trough usually developed along the beaches with immobile gully head as a result of the artificial dams and the swing range increased from gully head to the low reaches,so they have been obviously impacted by human activity and have longer swing periods;(2) Periodic and actively,this kind of trough,which swung with a fast rate and moved periodically on sand ridges,were mainly controlled by the swings of the host tidal troughs and hydrodynamic forces upon tidal sand ridge and influenced slightly by human constructions;(3) Steadily and slowly,they are the main tidal troughs with large scale and a steady orientation in this area and have slow lateral movement.The differences in migration mode of tidal trough shift result in different rates of migration and impact upon tidal sand ridges.Lateral accumulation on current tidal trough and deposition on abandoned tidal troughs are the two types of sedimentation of the tidal sand ridges formation.The whole radial sand ridge was generally prone to division and retreat although sand ridges fluctuated by the analysis of changes in talwegs of tidal troughs and shorelines of sand ridges.展开更多
The delta evolution and erosion process of the abandoned Yellow River Delta （AYRD） have been extensively studied. However, the variation of sediment at a large littoral scale along the north coast of Jiangsu is less...The delta evolution and erosion process of the abandoned Yellow River Delta （AYRD） have been extensively studied. However, the variation of sediment at a large littoral scale along the north coast of Jiangsu is less understood. In this study, the data of surface sediment samples obtained in the littoral area of the Yellow River Delta in 2006 and 2012 is used to study the sediment variability and sediment transport trends by using the geostatistics analysis tool and the grain size trend analysis model, In order to ensure the applicability of the model, the geostatistics method is used to determine the characteristic distance （De） with the average range value （Ao） of grain size parameter. Filtering method （removing data that not at a sampling station） is used to improve accuracy of data selection. The results show that sedimentary spatial correlation in Lianyun Port area and southern part of the abandoned Yellow River Delta （AS） is better than that in the northern part of the abandoned Yellow River Delta （AN）. Sediment in the area is found to be anisotropy at the northeast-southeast direc- tion. The grain size trend analysis reveals that the sediment trend is towards bayhead and southerly in the Haizhou Bay, southeasterly along the shoreline in the south Lianyun Port, northwesterly in AN and easterly-southeasterly in AS respectively. The investigation of possible relationships between Do, Ao, sediment transport and delta evolution shows a close link between Do and Ao of one sediment combination. It is also found that sediment transport trends could reasonably represent the delta evolution to a certain degree.展开更多
The sediment load in the Yangtze River downstream of the Three Gorges Dam(TGD)has substantially declined in recent decades.The decrease is more profound below the TGD,e.g.,a 97%decrease at Yichang,compared with that a...The sediment load in the Yangtze River downstream of the Three Gorges Dam(TGD)has substantially declined in recent decades.The decrease is more profound below the TGD,e.g.,a 97%decrease at Yichang,compared with that at the delta apex,1200 km downstream,e.g.,a 75%decrease,implying along-river sediment recovery.Two large river-connected lakes,i.e.,Dongting and Poyang Lakes,may play a role in the re-establishment of the river’s morphodynamic equilibrium,but a quantitative data-based understanding of this interaction is not yet available.In this work,we collected a series of field data to quantify the sediment gain and loss in the river-lake system in the middle-lower Yangtze River,and evaluate the lake’s response to the reduction in riverine sediment supply.We find that Dongting Lake and Poyang Lake shifted from net sedimentation to erosion in 2006 and 2000,and back to a sedimentation regime again after 2017 and 2018,respectively.Natural morphodynamic adaptation and sand mining play an important role in the regime changes in the Dongting Lake whereas sand mining dominates the abrupt changes in the Poyang Lake.The Dongting and Poyang Lake contributed maximum by 38%(2015)and 17%(2006)(respectively)to the sediment recovery in the erosion regime,whereas the riverbed erosion dominates the main sediment source.These changes in the relative contribution of sediment sources also indicates a response time of~20 years in the lakes towards a new equilibrium state.It is noteworthy that the lakes’buffer effects may be overestimated as the supplied sediment from the lakes is rather small compared to the significant dam trapping in the upstream basin and sediment source from downstream degradation.The results imply that river management and restoration should take into account of the river-lake interactions and feedback impact at decadal time scales.展开更多
Correction:Anthropocene Coasts 6,2(2023)https://doi.org/10.1007/s44218-022-00015-1 Following publication of the original article(Zhu et al.2023),the authors reported that Fig.1 needed to be updated.The correct Fig.1 h...Correction:Anthropocene Coasts 6,2(2023)https://doi.org/10.1007/s44218-022-00015-1 Following publication of the original article(Zhu et al.2023),the authors reported that Fig.1 needed to be updated.The correct Fig.1 has been provided in this Correction.The original article(Zhu et al.2023)has been corrected.展开更多
基金Supported by the National Basic Research Program of China (973 Program) (Nos 40176021,40676037 and 40706027)
文摘Using satellite images taken on different dates,GIS analysis of aerial photos,bathymetric maps and other field survey data,tidal troughs and major sand ridges in the northern Jiangsu coastal area were contrasted.The results show that there have been three types of movement or migration of tidal trough in this area:(1) Periodic and restricted,this type of trough usually developed along the beaches with immobile gully head as a result of the artificial dams and the swing range increased from gully head to the low reaches,so they have been obviously impacted by human activity and have longer swing periods;(2) Periodic and actively,this kind of trough,which swung with a fast rate and moved periodically on sand ridges,were mainly controlled by the swings of the host tidal troughs and hydrodynamic forces upon tidal sand ridge and influenced slightly by human constructions;(3) Steadily and slowly,they are the main tidal troughs with large scale and a steady orientation in this area and have slow lateral movement.The differences in migration mode of tidal trough shift result in different rates of migration and impact upon tidal sand ridges.Lateral accumulation on current tidal trough and deposition on abandoned tidal troughs are the two types of sedimentation of the tidal sand ridges formation.The whole radial sand ridge was generally prone to division and retreat although sand ridges fluctuated by the analysis of changes in talwegs of tidal troughs and shorelines of sand ridges.
基金Special Funding of Global Change Research Major Scientific Research Plan Project,No.2010CB951202State Key Laboratory of Estuarine and Coastal Research,ECNU,No.SKLEC-2012KYYW06
文摘The delta evolution and erosion process of the abandoned Yellow River Delta （AYRD） have been extensively studied. However, the variation of sediment at a large littoral scale along the north coast of Jiangsu is less understood. In this study, the data of surface sediment samples obtained in the littoral area of the Yellow River Delta in 2006 and 2012 is used to study the sediment variability and sediment transport trends by using the geostatistics analysis tool and the grain size trend analysis model, In order to ensure the applicability of the model, the geostatistics method is used to determine the characteristic distance （De） with the average range value （Ao） of grain size parameter. Filtering method （removing data that not at a sampling station） is used to improve accuracy of data selection. The results show that sedimentary spatial correlation in Lianyun Port area and southern part of the abandoned Yellow River Delta （AS） is better than that in the northern part of the abandoned Yellow River Delta （AN）. Sediment in the area is found to be anisotropy at the northeast-southeast direc- tion. The grain size trend analysis reveals that the sediment trend is towards bayhead and southerly in the Haizhou Bay, southeasterly along the shoreline in the south Lianyun Port, northwesterly in AN and easterly-southeasterly in AS respectively. The investigation of possible relationships between Do, Ao, sediment transport and delta evolution shows a close link between Do and Ao of one sediment combination. It is also found that sediment transport trends could reasonably represent the delta evolution to a certain degree.
基金supported by the project‘Coping with deltas in transition’within the Program of Strategic Scientific Alliance between China and The Netherlands(PSA),financed by the Ministry of Science and Technology,P.R.China(MOST)(No.2016YFE0133700)Royal Netherlands Academy of Arts and Sciences(KNAW)(Grant No.PSA-SA-E-02)+2 种基金Natural Science Foundation of China(NSFC)(Nos.51739005,U2040216,41876091,51909101,42006150,42206169)Shanghai Committee of Science and Technology(Nos.20DZ120470021230750600).
文摘The sediment load in the Yangtze River downstream of the Three Gorges Dam(TGD)has substantially declined in recent decades.The decrease is more profound below the TGD,e.g.,a 97%decrease at Yichang,compared with that at the delta apex,1200 km downstream,e.g.,a 75%decrease,implying along-river sediment recovery.Two large river-connected lakes,i.e.,Dongting and Poyang Lakes,may play a role in the re-establishment of the river’s morphodynamic equilibrium,but a quantitative data-based understanding of this interaction is not yet available.In this work,we collected a series of field data to quantify the sediment gain and loss in the river-lake system in the middle-lower Yangtze River,and evaluate the lake’s response to the reduction in riverine sediment supply.We find that Dongting Lake and Poyang Lake shifted from net sedimentation to erosion in 2006 and 2000,and back to a sedimentation regime again after 2017 and 2018,respectively.Natural morphodynamic adaptation and sand mining play an important role in the regime changes in the Dongting Lake whereas sand mining dominates the abrupt changes in the Poyang Lake.The Dongting and Poyang Lake contributed maximum by 38%(2015)and 17%(2006)(respectively)to the sediment recovery in the erosion regime,whereas the riverbed erosion dominates the main sediment source.These changes in the relative contribution of sediment sources also indicates a response time of~20 years in the lakes towards a new equilibrium state.It is noteworthy that the lakes’buffer effects may be overestimated as the supplied sediment from the lakes is rather small compared to the significant dam trapping in the upstream basin and sediment source from downstream degradation.The results imply that river management and restoration should take into account of the river-lake interactions and feedback impact at decadal time scales.
文摘Correction:Anthropocene Coasts 6,2(2023)https://doi.org/10.1007/s44218-022-00015-1 Following publication of the original article(Zhu et al.2023),the authors reported that Fig.1 needed to be updated.The correct Fig.1 has been provided in this Correction.The original article(Zhu et al.2023)has been corrected.
