The Changjiang Estuary is characterized by multi-order bifurcations, unsteady submerged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusi...The Changjiang Estuary is characterized by multi-order bifurcations, unsteady submerged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusion from the sea; (2) intrusion during tidal flooding; (3) intrusion from tidal flats overflow; and (4) salt water coming upstream through other waterways. These result in a complicated temporal and spatial salinity distribution. A high chlorinity concentration zone exists from the Liuhekou to the Sidongkou along the South Branch. The salinity during neap tide or ordinary tide is higher than during spring tide.展开更多
The characteristics, pattern, hydrodynamic and hydrochemical features, and the movement pattern of the salt water-fresh water interface of the sea water intrusion and the salt water intrusion, which occur in the coast...The characteristics, pattern, hydrodynamic and hydrochemical features, and the movement pattern of the salt water-fresh water interface of the sea water intrusion and the salt water intrusion, which occur in the coastal area of Laizhou Bay in Shandong Province, are analysed. The characteristics of the two kinds of intrusion are compared as well. A three-dimensional sea water intrusion model to describe the sea water intrusion with a transitional zone 1.56.0 km wide in the phreatic aquifer and a solute transport model describing the behavior of cations exchange in the process of sea water intrusion are established.展开更多
Using the methods of empirical correlation and numerical analogue computation of the longitudinal distribution of two-dimensional chlorinity and combined with the actual situation of water supply in the Changjiang Est...Using the methods of empirical correlation and numerical analogue computation of the longitudinal distribution of two-dimensional chlorinity and combined with the actual situation of water supply in the Changjiang Estuary, a calculation and analysis have been made in this paper of the impacts of sea level rise of 0.5—1.0 m in the Changjiang Estuary in the next century on the probabilities of hourly chlorinity of more than 100×10^(-6), 200×10^(-6) and 250×10^(-6) during the dry season st Wusong station and on the intrusion distance of the isohalines of 1×10^(-3) and 5×10^(-3) during the ebb tide stand of the dry season in the South Branch as well as on the longitudinal distribution of the chlorinity of the South Branch in the most unfavorable situation with the minimum monthly mean discharge during the special dry year.展开更多
A series of numerical experiments have been carried out to study the dynamics of the Kuroshio intrusion into the north South China Sea (SCS) and the East China Sea (ECS). The Kuroshio itself can intrude into the SCS t...A series of numerical experiments have been carried out to study the dynamics of the Kuroshio intrusion into the north South China Sea (SCS) and the East China Sea (ECS). The Kuroshio itself can intrude into the SCS through the middle Luzon Strait, and into the ECS northeast to Taiwan and west of Tokara Strait. An inshore current from the north SCS through Taiwan Strait, shelf region of the ECS and to the Korea Strait is induced. The numerical experiments show that the momentum advection plays a substantial role in generating the NW Luzon Cyclonic Gyre (NWLCG) and has great influence on the pathway of the SCS Branch of the Kuroshio. The NWLCG is thus partly of inertial recirculation recirculation. Topography is a key factor for the formation of the circulation in the study area. The beta effect and momentum advention may intensify the Kuroshio intrusion northeast of Taiwan to a certain degree, but not large.展开更多
Saltwater intrusion is a major cause of coastal erosion. New hybrid bald cypress species have been shown to exhibit salinity tolerance compared to native bald cypress species. Planting these hybrids, or Nanjing Bot Ga...Saltwater intrusion is a major cause of coastal erosion. New hybrid bald cypress species have been shown to exhibit salinity tolerance compared to native bald cypress species. Planting these hybrids, or Nanjing Bot Garden genotype (NBG), trees where their roots can stabilize soil and preserve land may reduce coastal erosion in areas subjected to saltwater intrusion. The purpose of this experiment was to determine whether or not selected bald cypress NBG genotype tree species survive better than native bald cypress trees in areas inundated with saline water. Leaves were harvested, dried and analyzed for their elemental concentration. NBG genotype trees excluded more sodium than native bald cypress trees. NBG genotype tree roots were also less effected by brackish water. Finally, the growth of the NBG genotype trees and the control were measured. All NBG genotype trees tested showed growth while the control trees maintained little or no growth, and a decrease in tree height in sodic soil. If these NBG genotype trees are subjected to a surge of brackish water, NBG genotype bald cypress trees may be used to stabilize soil that may be otherwise subject to coastal erosion.展开更多
Seawater flows towards the inlands along with the rivers and canals, through the process of infiltration and leaks in the ground water characterized by high concentrations of soluble salts. High salinity concentration...Seawater flows towards the inlands along with the rivers and canals, through the process of infiltration and leaks in the ground water characterized by high concentrations of soluble salts. High salinity concentrations can make groundwater unsuitable for public consumption and surface water unsuitable for irrigation and agricultural activities. This study envisages the fluctuations of ground and surface water quality of Bentota area in the presence of seawater intrusion. The temporal and spatial variations of eleven water parameters were monitored by collecting the water samples during one year period. Spatial distributions were assessed by applying the Inverse distance weighted (IDW) interpolation method in Arc GIS 10.5 software. Water quality is assessed on the integration of all parameters in terms of an index based on the World Health Organization (WHO) standards. The significant linear relationship between the considered parameters of surface water (SW) and groundwater (GW) were identified applying correlation analysis using SPSS software. All parameters of surface water were above the permissible limits of WHO standards. Surface water quality index values with respect to 60% of canals show very poor quality (>1 250) of surface water indicating their unsuitability for irrigation activities. Those surface water bodies indicated very highly saline conditions during dry months. The spatial distribution of ground water quality index with respect to the highest parameter values of each sampling location indicates that 52.2% of total land extent of Bentota Divisional Secretariat Division (DSD) has good quality of ground water which is suitable for drinking. Its 47.2% of total land extent has poor quality of ground water for drinking purpose and less than 0.5% of the area consists of excellent or very poor quality of ground water in each. This study helps to manage coastal aquifers by understanding the extreme water quality conditions and coastal salinity.展开更多
As a worldwide authoritative, IPCC forecasted in 1990 that the world- s sea level would most probably rise by 0. 66 m by the end of the 21 st century. Combined with the local depression caused by the sink of the earth...As a worldwide authoritative, IPCC forecasted in 1990 that the world- s sea level would most probably rise by 0. 66 m by the end of the 21 st century. Combined with the local depression caused by the sink of the earth’s crust and the human activity, the relative sea level in the Chanaiiang River mouth will rise by about 1. 0 m during the same peried. Based on this figure, the article forecasted the impacts of sea-level rise on the safety coefficient of coastal structures and civil facilities, loss of wetlands, flood hazard as well as water intrusion. The results show that: 1 ) 40% as large as the present engil1eering mass should be added to the coastal structures in order to maintain the safety coefficient; 2 ) a dynamic loss of 60 km2 of wetlands, as much as 15% of the present total area, would be caused; 3) to hinder the increase inflood hazard dy11amic capacity to drain water must increase by at least 34 times as large as the present; 4) to maintain the present navigation conditions, about 100 million yuan (RMB) is needed to reconstruct over 30(X) bridges and 30 sluices;and 5 ) the disastrous salt water intrusion caused by the sea-level rise could be encountered by the increase in water discharge from the Three Gorge Reservoir in the dry season.展开更多
Marine sedimentary strata are widely distributed in the coastal zone of the study area, and are rich in brine resources. The exploitation of underground water resources often first caused the intrusion of salt water i...Marine sedimentary strata are widely distributed in the coastal zone of the study area, and are rich in brine resources. The exploitation of underground water resources often first caused the intrusion of salt water in the marine strata. Based on the analysis of sea-salt water intrusion feature, the sea-salt water intrusion is divided into four stages: The occurrence and development stage(1976–1985), the rapid development stage(1986–1990), the slow development stage(1990–2000) and the stable development stage(2000–2015). Based on the comparative analysis of the relationship between seawater intrusion and influencing factors, this paper presents that the groundwater exploitation and the brine resources mining are the main control factors of sea-salt water intrusion. On this basis, we have established a numerical model of the sea-salt water intrusion. Using this model, we predicted the development trend of the sea-salt water intrusion. The results show that if the current development of groundwater and brine is maintained, the sea-salt water intrusion will gradually withdraw; once development of brine stops, sea-salt water will invade again. This provides the scientific basis for the rational exploitation of groundwater and the prevention of sea-salt water intrusion.展开更多
The south coastal plain of Laizhou Bay is one of the typical salt-water intrusion areas in China, the occurrence and development of which was closely related with the palaeoenvironment evolution. Systematic analyses o...The south coastal plain of Laizhou Bay is one of the typical salt-water intrusion areas in China, the occurrence and development of which was closely related with the palaeoenvironment evolution. Systematic analyses of pollen, foraminifera and grain size composition based on ^14C and luminescence dating from two sediment cores were performed for the purpose of understanding the salt-water intrusion in the coastal plain of Laizhou Bay from the perspective of environmental evolution since late Pleistocene. It could be classified into seven evolution stages since 120 kaBP： 120-85 kaBP was a transition period from cold to warm; 85-76 kaBP was a period with warm and wet climate having swamp lakes developed in the lower reaches of the Weihe River, south coastal plain of Laizhou Bay; 76-50 kaBP was characterized by grassland vegetation and coarse sediments in terrestrial environment, which was the early stage of Dali Ice-Age; 50-24 kaBP was a period with alternate sea deposition in the south coastal plain of Laizhou Bay; 24-10 kaBP was the late stage of Dali Ice-Age with coldest period of Quaternary, the south coastal plain of Laizhou Bay was dry grassland and loess deposition environment; 10-4 kaBP was another warm and wet climate period, sea level was high and regressed at 4 kaBP; and has been the modern sedimentary environment since 4 kaBP. Among the three warm stages, including 85-76 kaBP, 50-24 kaBP and 10-4 kaBP, corresponded to late Yangkou, Guangrao and Kenli seawater transgression respectively. The duration of the latter one in south coastal plain of Laizhou Bay was longer than that in west coast of Bohai Sea and east coast of Laizhou Bay. The three periods of seawater transgression formed the foundation of salt-water intrusion in this area.展开更多
The objective of this study is to understand the validity of salinity vertical profiles collected from shallow piezometers that are not previously flushed. This study shows that salinity data collected from boreholes ...The objective of this study is to understand the validity of salinity vertical profiles collected from shallow piezometers that are not previously flushed. This study shows that salinity data collected from boreholes are only an average value along the entire screened section of the piezometer. In order to collect data that is rep-resentative for the salinity of the adjacent aquifer, a new monitoring strategy has been developed. This strat-egy includes measurement of the salinity at the top of the watertable in an auger hole which is a shallow boreholes made with an handheld drill. This should be combined with measurements in piezometers that are first flushed to take out stagnant water. From the piezometers on can measure the average salinity of the screened part and the salinity at the bottom of the aquifer. By using this monitoring strategy it is also possi-ble to define where the piezometers screens are located if this is not known beforehand.展开更多
基金The authors gratefully acknowledge the help of fellow workers during field work and Li, W., Wu, R., for analysis of water samples The authors thank Dr. Zhang, S., Nanjing Institute of Geography and Limnology for his advice on the preparation of this pa
文摘The Changjiang Estuary is characterized by multi-order bifurcations, unsteady submerged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusion from the sea; (2) intrusion during tidal flooding; (3) intrusion from tidal flats overflow; and (4) salt water coming upstream through other waterways. These result in a complicated temporal and spatial salinity distribution. A high chlorinity concentration zone exists from the Liuhekou to the Sidongkou along the South Branch. The salinity during neap tide or ordinary tide is higher than during spring tide.
文摘The characteristics, pattern, hydrodynamic and hydrochemical features, and the movement pattern of the salt water-fresh water interface of the sea water intrusion and the salt water intrusion, which occur in the coastal area of Laizhou Bay in Shandong Province, are analysed. The characteristics of the two kinds of intrusion are compared as well. A three-dimensional sea water intrusion model to describe the sea water intrusion with a transitional zone 1.56.0 km wide in the phreatic aquifer and a solute transport model describing the behavior of cations exchange in the process of sea water intrusion are established.
基金Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘Using the methods of empirical correlation and numerical analogue computation of the longitudinal distribution of two-dimensional chlorinity and combined with the actual situation of water supply in the Changjiang Estuary, a calculation and analysis have been made in this paper of the impacts of sea level rise of 0.5—1.0 m in the Changjiang Estuary in the next century on the probabilities of hourly chlorinity of more than 100×10^(-6), 200×10^(-6) and 250×10^(-6) during the dry season st Wusong station and on the intrusion distance of the isohalines of 1×10^(-3) and 5×10^(-3) during the ebb tide stand of the dry season in the South Branch as well as on the longitudinal distribution of the chlorinity of the South Branch in the most unfavorable situation with the minimum monthly mean discharge during the special dry year.
文摘A series of numerical experiments have been carried out to study the dynamics of the Kuroshio intrusion into the north South China Sea (SCS) and the East China Sea (ECS). The Kuroshio itself can intrude into the SCS through the middle Luzon Strait, and into the ECS northeast to Taiwan and west of Tokara Strait. An inshore current from the north SCS through Taiwan Strait, shelf region of the ECS and to the Korea Strait is induced. The numerical experiments show that the momentum advection plays a substantial role in generating the NW Luzon Cyclonic Gyre (NWLCG) and has great influence on the pathway of the SCS Branch of the Kuroshio. The NWLCG is thus partly of inertial recirculation recirculation. Topography is a key factor for the formation of the circulation in the study area. The beta effect and momentum advention may intensify the Kuroshio intrusion northeast of Taiwan to a certain degree, but not large.
文摘Saltwater intrusion is a major cause of coastal erosion. New hybrid bald cypress species have been shown to exhibit salinity tolerance compared to native bald cypress species. Planting these hybrids, or Nanjing Bot Garden genotype (NBG), trees where their roots can stabilize soil and preserve land may reduce coastal erosion in areas subjected to saltwater intrusion. The purpose of this experiment was to determine whether or not selected bald cypress NBG genotype tree species survive better than native bald cypress trees in areas inundated with saline water. Leaves were harvested, dried and analyzed for their elemental concentration. NBG genotype trees excluded more sodium than native bald cypress trees. NBG genotype tree roots were also less effected by brackish water. Finally, the growth of the NBG genotype trees and the control were measured. All NBG genotype trees tested showed growth while the control trees maintained little or no growth, and a decrease in tree height in sodic soil. If these NBG genotype trees are subjected to a surge of brackish water, NBG genotype bald cypress trees may be used to stabilize soil that may be otherwise subject to coastal erosion.
文摘Seawater flows towards the inlands along with the rivers and canals, through the process of infiltration and leaks in the ground water characterized by high concentrations of soluble salts. High salinity concentrations can make groundwater unsuitable for public consumption and surface water unsuitable for irrigation and agricultural activities. This study envisages the fluctuations of ground and surface water quality of Bentota area in the presence of seawater intrusion. The temporal and spatial variations of eleven water parameters were monitored by collecting the water samples during one year period. Spatial distributions were assessed by applying the Inverse distance weighted (IDW) interpolation method in Arc GIS 10.5 software. Water quality is assessed on the integration of all parameters in terms of an index based on the World Health Organization (WHO) standards. The significant linear relationship between the considered parameters of surface water (SW) and groundwater (GW) were identified applying correlation analysis using SPSS software. All parameters of surface water were above the permissible limits of WHO standards. Surface water quality index values with respect to 60% of canals show very poor quality (>1 250) of surface water indicating their unsuitability for irrigation activities. Those surface water bodies indicated very highly saline conditions during dry months. The spatial distribution of ground water quality index with respect to the highest parameter values of each sampling location indicates that 52.2% of total land extent of Bentota Divisional Secretariat Division (DSD) has good quality of ground water which is suitable for drinking. Its 47.2% of total land extent has poor quality of ground water for drinking purpose and less than 0.5% of the area consists of excellent or very poor quality of ground water in each. This study helps to manage coastal aquifers by understanding the extreme water quality conditions and coastal salinity.
文摘As a worldwide authoritative, IPCC forecasted in 1990 that the world- s sea level would most probably rise by 0. 66 m by the end of the 21 st century. Combined with the local depression caused by the sink of the earth’s crust and the human activity, the relative sea level in the Chanaiiang River mouth will rise by about 1. 0 m during the same peried. Based on this figure, the article forecasted the impacts of sea-level rise on the safety coefficient of coastal structures and civil facilities, loss of wetlands, flood hazard as well as water intrusion. The results show that: 1 ) 40% as large as the present engil1eering mass should be added to the coastal structures in order to maintain the safety coefficient; 2 ) a dynamic loss of 60 km2 of wetlands, as much as 15% of the present total area, would be caused; 3) to hinder the increase inflood hazard dy11amic capacity to drain water must increase by at least 34 times as large as the present; 4) to maintain the present navigation conditions, about 100 million yuan (RMB) is needed to reconstruct over 30(X) bridges and 30 sluices;and 5 ) the disastrous salt water intrusion caused by the sea-level rise could be encountered by the increase in water discharge from the Three Gorge Reservoir in the dry season.
基金supported by Geological prospecting project in Shandong Province([2011]14)
文摘Marine sedimentary strata are widely distributed in the coastal zone of the study area, and are rich in brine resources. The exploitation of underground water resources often first caused the intrusion of salt water in the marine strata. Based on the analysis of sea-salt water intrusion feature, the sea-salt water intrusion is divided into four stages: The occurrence and development stage(1976–1985), the rapid development stage(1986–1990), the slow development stage(1990–2000) and the stable development stage(2000–2015). Based on the comparative analysis of the relationship between seawater intrusion and influencing factors, this paper presents that the groundwater exploitation and the brine resources mining are the main control factors of sea-salt water intrusion. On this basis, we have established a numerical model of the sea-salt water intrusion. Using this model, we predicted the development trend of the sea-salt water intrusion. The results show that if the current development of groundwater and brine is maintained, the sea-salt water intrusion will gradually withdraw; once development of brine stops, sea-salt water will invade again. This provides the scientific basis for the rational exploitation of groundwater and the prevention of sea-salt water intrusion.
基金National Natural Science Foundation of China, No.40471122
文摘The south coastal plain of Laizhou Bay is one of the typical salt-water intrusion areas in China, the occurrence and development of which was closely related with the palaeoenvironment evolution. Systematic analyses of pollen, foraminifera and grain size composition based on ^14C and luminescence dating from two sediment cores were performed for the purpose of understanding the salt-water intrusion in the coastal plain of Laizhou Bay from the perspective of environmental evolution since late Pleistocene. It could be classified into seven evolution stages since 120 kaBP： 120-85 kaBP was a transition period from cold to warm; 85-76 kaBP was a period with warm and wet climate having swamp lakes developed in the lower reaches of the Weihe River, south coastal plain of Laizhou Bay; 76-50 kaBP was characterized by grassland vegetation and coarse sediments in terrestrial environment, which was the early stage of Dali Ice-Age; 50-24 kaBP was a period with alternate sea deposition in the south coastal plain of Laizhou Bay; 24-10 kaBP was the late stage of Dali Ice-Age with coldest period of Quaternary, the south coastal plain of Laizhou Bay was dry grassland and loess deposition environment; 10-4 kaBP was another warm and wet climate period, sea level was high and regressed at 4 kaBP; and has been the modern sedimentary environment since 4 kaBP. Among the three warm stages, including 85-76 kaBP, 50-24 kaBP and 10-4 kaBP, corresponded to late Yangkou, Guangrao and Kenli seawater transgression respectively. The duration of the latter one in south coastal plain of Laizhou Bay was longer than that in west coast of Bohai Sea and east coast of Laizhou Bay. The three periods of seawater transgression formed the foundation of salt-water intrusion in this area.
文摘The objective of this study is to understand the validity of salinity vertical profiles collected from shallow piezometers that are not previously flushed. This study shows that salinity data collected from boreholes are only an average value along the entire screened section of the piezometer. In order to collect data that is rep-resentative for the salinity of the adjacent aquifer, a new monitoring strategy has been developed. This strat-egy includes measurement of the salinity at the top of the watertable in an auger hole which is a shallow boreholes made with an handheld drill. This should be combined with measurements in piezometers that are first flushed to take out stagnant water. From the piezometers on can measure the average salinity of the screened part and the salinity at the bottom of the aquifer. By using this monitoring strategy it is also possi-ble to define where the piezometers screens are located if this is not known beforehand.
