Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tida...Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tidal flat reclamation and environment protection becomes more and more outstanding. However, tidal flat reclamation should also follow the dynamic balance of total amount of tidal flat amount. The paper analyzed the history of reclamation and development of Jiangsu mud coast, and calculated the feasible rates of tidal flat reclamation on different stretches respectively, and pointed out that both the economic social benefits of reclamation and the natural erosion-accretion conditions of the coasts should be taken into consideration in deciding the intensity of tidal flat reclamation, so as to satisfy demands on both reclamation and protection of tidal flat resource.展开更多
This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current ...This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include： the Taiwan Warm Current （TWC）, the Huanghai Sea Mixed Water （HSMW）, North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.展开更多
The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain polluta...The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain pollutants, like phosphorus in excess. By mapping the source areas of erosion, the authors can determine the risk areas and help to prioritize interventions in the territory. This mapping is done using the SWAT （soil and water assessment tool） model. Several types of data, including topography, land use, soil and climate data are needed to run the model. In this paper, all different steps are presented, from the designing of HRU （hydrological response units）, basic units to run the SWAT model until the simulations. The establishment of HRU has three main stages： space discretization, land use and soil data integration and HRU distribution： （1） space discretization which consist in extracting the limits and the water network of the watershed from the DEM （digital elevation model） and in subdividing them into sub-basins; （2） land use and soil data integration： it consists in digitizing the physical maps of land use and of soils under Mapinfo 7.5 and in keeping them in ＂shape＂ format; （3） HRU distribution： it leads to subdivide the sub-watersheds in small units that combine a single soil type and one type of land use. It appears from this study to obtain 23 sub-watersheds and 71 HRU. Once the HRU designed, it is necessary to integrate climate data, data on physico-chemical characteristics of soils and agricultural practices, before starting the simulations. This will allow the model to assess the risk of sedimentation and eutrophication of the lake using the MUSLE （modified universal soil loss equation） and phosphorus cycle.展开更多
To examine spatial variations of grain-size characteristics caused by both natural and human-induced processes along the Lianyungang muddy coast, China, 129 samples were collected and measured using standard sieving a...To examine spatial variations of grain-size characteristics caused by both natural and human-induced processes along the Lianyungang muddy coast, China, 129 samples were collected and measured using standard sieving and sedimentation techniques. Results show that sediment diameter tends to increase with increasing water depth from nearshore to offshore. Size-frequency distributions indicate a gradual mixing process of coarse and fine diameter material. Grain size trend analysis indicates that a man-made structure, the West has resulted in severe siltation in Haizhou Bay and Breakwater, along with Liandao Island itself, the Lianyungang port area, where sediment quality is also poor. Results demonstrate that grain size can be used as a natural tracer to infer how sediments respond to the effects caused by both natural and human-induced processes.展开更多
Neomysis awatschensis was collected on the west coast of Jiaozhou Bay, Qingdao in 1992 and acclimated in the laboratory conditions. The acute toxicity method using 4~ 6 day juvenile mysid of this species is studied. T...Neomysis awatschensis was collected on the west coast of Jiaozhou Bay, Qingdao in 1992 and acclimated in the laboratory conditions. The acute toxicity method using 4~ 6 day juvenile mysid of this species is studied. The species is compared with M. bahia in taxonomy, geographic distribution, morphology, as well as the sensitivity to reference toxins. Based on the results, we recommend N. awatschensis to be a standard marine organism for toxicity test in China and the method to be applied in toxicity evaluation of drilling fluids. In this paper, we report the results of the above studies and the application of the method in the evaluation of several drilling fluid products.展开更多
This paper presents the results of application of a 3D （three-dimensional） numerical model to study on MTZ （maximum turbidity zone） in the coastal zone of Mekong River Delta. In this study, a 3D system model with ...This paper presents the results of application of a 3D （three-dimensional） numerical model to study on MTZ （maximum turbidity zone） in the coastal zone of Mekong River Delta. In this study, a 3D system model with combination of hydrodynamics--wave and suspended sediment transport was set up and validated with measured data in the study area. Based on calculated scenarios for the flood and the dry season, the results have shown appearance of MTZs in the coastal zone of Mekong River with suspended sediment concentration prevalent of 0.04-0.07 kg·m^3 （the dry season） and 0.05-0.1kg·m^3 （the flood season）. The position and MTZs scale change with the interaction between fresh water and tidal oscillations. The MTZ occur more in the dry seasons compared to the wet season. The MTZs are prevalent located far away from estuaries about in 12-22 km （in the dry season）, and 5-15 km in the flood season.展开更多
Movement of sediment load and its pattern of transportation along nearshore coastal water is a very important phenomenon to be assessed for different sector of coastal Engineering. To develop and understand the physic...Movement of sediment load and its pattern of transportation along nearshore coastal water is a very important phenomenon to be assessed for different sector of coastal Engineering. To develop and understand the physical processes responsible for shaping the ongoing evolution of the coast and to develop the management strategies to deal the impact of human activities on the coastal zone and as well as for adapting to the hazards associated with the people living on the coast, knowledge of the mechanism, processes and the pattern of sediment movement in the nearshore zone is of utmost importance. Nearshore zone is a very active area, where a series of dynamic processes occur in response to changing wave climates and sediment budgets. Nowadays mathematical modeling is an attractive alternative and becoming a very viable approach to study the sediment movement pattern with the advanced computational facilities and improved understanding on wave mechanics and sediment transport processes. It is very effective, reliable and also comfortable to study the pattern of sediment transportation including yield, distribution and management of sediment with the help of mathematical model. Validity of forecast in sediment transport depends on both mathematical modeling technique and boundary conditions.展开更多
This paper synthesizes the extent and nature of scientific information about how dredging activities potentially affect habitats and key ecological functions supporting recruitment and sustainability of estuarine and ...This paper synthesizes the extent and nature of scientific information about how dredging activities potentially affect habitats and key ecological functions supporting recruitment and sustainability of estuarine and marine environment. Fourteen samples were collected after dredging （2008） from fixed sampling stations. The impact on community was estimated at species level （Foraminifera, Protozoan, using statistical analysis）. The maximum negative effect on benthic foraminifera was reduction by 60%, for species richness and by 50% for diversity. This data were compared with the data obtained before dredging （2006） in a time services spanning 2 years. Its revealed that reestablishment of directly with in less than 3 months of the end of dredging, although affected foraminifera and of physico-chemical substrate characteristic 2 years later there was a considerable improvement of whole faunal community. Statistical treatment was given to the data sets to know the relation among parameters. Before, this type of activity is undertaken, each case should be studied regarding viability, the environmental medium where it will take place, the best time of year, and the type of dredging to be used. Small-patch dredging operations are proposed when ever possible, since they allow a quick readjustment of the initial sediment structure and benthic foraminifera. These findings will help to underpin improved planning of management strategies for dredging operations in India and other countries.展开更多
文摘Reclamation of tidal flat is one of the main ways to get a dynamic balance of the total amount of plowland. With the development of social economy and the increasing demand for plowland, the contradiction between tidal flat reclamation and environment protection becomes more and more outstanding. However, tidal flat reclamation should also follow the dynamic balance of total amount of tidal flat amount. The paper analyzed the history of reclamation and development of Jiangsu mud coast, and calculated the feasible rates of tidal flat reclamation on different stretches respectively, and pointed out that both the economic social benefits of reclamation and the natural erosion-accretion conditions of the coasts should be taken into consideration in deciding the intensity of tidal flat reclamation, so as to satisfy demands on both reclamation and protection of tidal flat resource.
文摘This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include： the Taiwan Warm Current （TWC）, the Huanghai Sea Mixed Water （HSMW）, North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment toward the sea. In the flood season, apart from the limitation by coastal current systems, the spatial and temporal distribution of suspended sediment is also affected by the runoff, which shows as the jet stream and fresh water. Spring and autumn are the transitional periods of the forming of expanding patterns of flood season and winter respectively. In addition, the re-suspended sediment caused by the wind wave may make the expanding range of near-shore sediment larger.
文摘The changes in land use in the last 30 years in the territory of agro-forest watershed of Lake Buyo resulted in significant sediment into the lake. Sediments are a preferred means of transportation for certain pollutants, like phosphorus in excess. By mapping the source areas of erosion, the authors can determine the risk areas and help to prioritize interventions in the territory. This mapping is done using the SWAT （soil and water assessment tool） model. Several types of data, including topography, land use, soil and climate data are needed to run the model. In this paper, all different steps are presented, from the designing of HRU （hydrological response units）, basic units to run the SWAT model until the simulations. The establishment of HRU has three main stages： space discretization, land use and soil data integration and HRU distribution： （1） space discretization which consist in extracting the limits and the water network of the watershed from the DEM （digital elevation model） and in subdividing them into sub-basins; （2） land use and soil data integration： it consists in digitizing the physical maps of land use and of soils under Mapinfo 7.5 and in keeping them in ＂shape＂ format; （3） HRU distribution： it leads to subdivide the sub-watersheds in small units that combine a single soil type and one type of land use. It appears from this study to obtain 23 sub-watersheds and 71 HRU. Once the HRU designed, it is necessary to integrate climate data, data on physico-chemical characteristics of soils and agricultural practices, before starting the simulations. This will allow the model to assess the risk of sedimentation and eutrophication of the lake using the MUSLE （modified universal soil loss equation） and phosphorus cycle.
基金Supported by the Natural Science Foundation of the Institutions of Higher Education of Jiangsu (No. 07KJD170012)
文摘To examine spatial variations of grain-size characteristics caused by both natural and human-induced processes along the Lianyungang muddy coast, China, 129 samples were collected and measured using standard sieving and sedimentation techniques. Results show that sediment diameter tends to increase with increasing water depth from nearshore to offshore. Size-frequency distributions indicate a gradual mixing process of coarse and fine diameter material. Grain size trend analysis indicates that a man-made structure, the West has resulted in severe siltation in Haizhou Bay and Breakwater, along with Liandao Island itself, the Lianyungang port area, where sediment quality is also poor. Results demonstrate that grain size can be used as a natural tracer to infer how sediments respond to the effects caused by both natural and human-induced processes.
基金The work is supported by National Basic Research Project No. 2001CB409709, NNSFC project (49906007, 39950001, 20177023, 40076030), CAS Innovation Project (KZCX2-206), Direct Project of CAS and Project of the Commission of Science, Shandong Province.
文摘Neomysis awatschensis was collected on the west coast of Jiaozhou Bay, Qingdao in 1992 and acclimated in the laboratory conditions. The acute toxicity method using 4~ 6 day juvenile mysid of this species is studied. The species is compared with M. bahia in taxonomy, geographic distribution, morphology, as well as the sensitivity to reference toxins. Based on the results, we recommend N. awatschensis to be a standard marine organism for toxicity test in China and the method to be applied in toxicity evaluation of drilling fluids. In this paper, we report the results of the above studies and the application of the method in the evaluation of several drilling fluid products.
文摘This paper presents the results of application of a 3D （three-dimensional） numerical model to study on MTZ （maximum turbidity zone） in the coastal zone of Mekong River Delta. In this study, a 3D system model with combination of hydrodynamics--wave and suspended sediment transport was set up and validated with measured data in the study area. Based on calculated scenarios for the flood and the dry season, the results have shown appearance of MTZs in the coastal zone of Mekong River with suspended sediment concentration prevalent of 0.04-0.07 kg·m^3 （the dry season） and 0.05-0.1kg·m^3 （the flood season）. The position and MTZs scale change with the interaction between fresh water and tidal oscillations. The MTZ occur more in the dry seasons compared to the wet season. The MTZs are prevalent located far away from estuaries about in 12-22 km （in the dry season）, and 5-15 km in the flood season.
文摘Movement of sediment load and its pattern of transportation along nearshore coastal water is a very important phenomenon to be assessed for different sector of coastal Engineering. To develop and understand the physical processes responsible for shaping the ongoing evolution of the coast and to develop the management strategies to deal the impact of human activities on the coastal zone and as well as for adapting to the hazards associated with the people living on the coast, knowledge of the mechanism, processes and the pattern of sediment movement in the nearshore zone is of utmost importance. Nearshore zone is a very active area, where a series of dynamic processes occur in response to changing wave climates and sediment budgets. Nowadays mathematical modeling is an attractive alternative and becoming a very viable approach to study the sediment movement pattern with the advanced computational facilities and improved understanding on wave mechanics and sediment transport processes. It is very effective, reliable and also comfortable to study the pattern of sediment transportation including yield, distribution and management of sediment with the help of mathematical model. Validity of forecast in sediment transport depends on both mathematical modeling technique and boundary conditions.
文摘This paper synthesizes the extent and nature of scientific information about how dredging activities potentially affect habitats and key ecological functions supporting recruitment and sustainability of estuarine and marine environment. Fourteen samples were collected after dredging （2008） from fixed sampling stations. The impact on community was estimated at species level （Foraminifera, Protozoan, using statistical analysis）. The maximum negative effect on benthic foraminifera was reduction by 60%, for species richness and by 50% for diversity. This data were compared with the data obtained before dredging （2006） in a time services spanning 2 years. Its revealed that reestablishment of directly with in less than 3 months of the end of dredging, although affected foraminifera and of physico-chemical substrate characteristic 2 years later there was a considerable improvement of whole faunal community. Statistical treatment was given to the data sets to know the relation among parameters. Before, this type of activity is undertaken, each case should be studied regarding viability, the environmental medium where it will take place, the best time of year, and the type of dredging to be used. Small-patch dredging operations are proposed when ever possible, since they allow a quick readjustment of the initial sediment structure and benthic foraminifera. These findings will help to underpin improved planning of management strategies for dredging operations in India and other countries.
