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PRELIMINARY STUDY ON TRANSPORTATION AND DISTRIBUTION OF sediment load IN THE YANGTZE ESTUARY

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International Journal of sediment Research 1998年第4期 63-73页

作者： Qing HE 2 and Caixing YUN 3

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关键词： The Yangtze estuary sediment load Remote sensing techniques

RECENT CHANGES IN RUNOFF AND sediment load AND THEIR TENDENCY IN THE UPPER CHANGJIANG RIVER

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RECENT CHANGES IN RUNOFF AND SEDIMENT LOAD AND THEIR TENDENC...

sediment loads response to climate change:A preliminary study of eight large Chinese rivers

第九次河流泥沙国际学术大会

作者： Quanxi XUBureau of Hydrology, Changjiang River Water Resources Commission, Wuhan 430010,China College of Hydraulic and Hydropower, National Key Laboratory of Water Resources and Hydro-powerEngineering, Wuhan University, Wuhan 430072,China. Guoyu SHI and Zefang CHEN Bureau of Hydrology, Changjiang River Water Resources Commission, Wuhan 430010,China

＜正＞This paper statistically analyse the runoff and sediment load changes at the major stations in the Upper Changjiang River. Compared with the annual runoff and sediment load before 1990, there were three major changes of annual sediment load in the period of 1991-2002;the annual decrement was about 0.13×109t at Yichang Station;the annual increment was about 0.035×109t at Pingshan Station and the percentage （accounted by Yichang station） also increased from 51.8% to 71.9%;the annual decrement was about 0.0985×109t at Beibei Station and the percentage also decreased from 25.7% to 9.1%. Based on the analysis of several non-parameter statistical methods such as moving average check and Spearman order correlativity check, the paper concludes that the runoff changing tendency at Pingshan Station is not distinct, but the sediment load increasing tendency is distinct;the runoff and sediment load at Beibei Station decreased tendency aer very distinct;the runoff changing tendency at Yichang Station is not distinct, whereas the sediment load increasing tendency is distinct.

关键词： Upper Changjiang River Runoff sediment load Tendency analysis Correlativity check

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International Journal of sediment Research 2013年第1期28卷 1-14页

作者： X.X.LU L.S.RAN S.LIU T.JIANG S.R.ZHANG J.J.WANG Department of Geography National University of Singapore117570Singapore Global Change and Watershed Management Center Yunnan University of Finance and EconomicsYunnan National Climate Centre China Meteorological AdministrationBeijingChina College of Water Sciences Beijing Normal UniversityChina

Climate change characterized by increasing temperature is able to affect precipitation regime and thus surface ***,the manner in which river sediment loads respond to climate change is not well understood,and related assessment regarding the effect of climate change on sediment loads is *** present a quantitative estimate of changes in sediment loads(from 1.5 Gt yr-1pre-1990 to 0.6 Gt yr-1from 1991-2007) in response to climate change in eight large Chinese *** the past decades,precipitation change coupled with rising temperatures has played a significant role in influencing the sediment delivery dynamics,although human activities, such as reservoir construction,water diversion,sand mining and land cover change,are still the predominant forces. Lower precipitation coupled with rising temperatures has significantly reduced sediment loads delivered into the sea in semi-arid climates(4-61%).In contrast,increasingly warmer and wetter climates in subtropical zones has yielded more sediment(0.4-11%),although the increase was offset by human *** results indicate that,compared with mechanical retention by reservoirs,water reduction caused by climate change or human withdrawals has contributed more sediment reduction for the rivers with abundant sediment supply but limited transport capacity(e.g.,the Huanghe).Furthermore,our results indicate that every 1%change in precipitation has resulted in a 1.3%change in water discharge and a 2%change in sediment *** addition,every 1%change in water discharge caused by precipitation has led to a 1.6%change in sediment loads,but the same percentage of water discharge change caused largely by humans would only result in a 0.9%change in sediment *** figures can be used as a guideline for evaluating the responses of sediment loads to climate change in similar climate zones because future global warming will cause dramatic changes in water and sediment in river basins worldwide at rates previou

关键词： sediment load Climate change Human activity Water withdrawal Chinese rivers

Erosion Rates in Dam Catchments in Jordan—Effects of Topography, Geology, and Urbanizations

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Open Journal of Soil Science 2024年第5期14卷 319-331页

作者： Elias Salameh Hakam Al-Alami Ibraheem Hamdan Department of Geology University of Jordan Amman Amman Jordan Faculty of Earth and Environmental Sciences Department of Applied Earth and Environmental Sciences Al al-Bayt University Mafraq Jordan Environment Water and Energy Research Center Al al-Bayt University Mafraq Jordan

Erosion as a natural process produces soils, which are very important natural resources for the fest land plant- and animal kingdoms. Loss of the soil cover reduces agricultural production, biodiversity, and the role of soil as a filter for infiltrating water to replenish the groundwater. It also threatens the food supplies. The knowledge of erosion rates of rocks and terrains is important for developing proactive measures to protect soils from erosion and loss. In this study, erosion rates of catchment areas were calculated based on dams’ catchment extensions and the sediment loads transported by flood flows into dams’ lakes. The study results show that the chemically, via floodwater, transported quantities of materials are negligible compared to the solid materials transported by the water. It calculates erosion rates ranging from 0.013 to 0.212 mm/yr (13 - 212 m/106 yr) for the different catchment areas. Erosion rates in Jordan are, generally, higher than those calculated for the different parts of the world ranging from 2.5 to 60 m/106 yr. This fact can be explained by the very steep topography, calcareous rock cover of the catchment areas and the barren rock exposures.

关键词： Erosion Rates Jordan Dams sediment load

Impacts of urban headwater disturbances on downstream sediment loading where streamside management zones for forest harvesting activities are present downstream

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International Journal of sediment Research 2017年第4期32卷 555-563页

作者： Ilkim Cavus Latif Kalin Ferhat Kara Ministry of Forestry and Water Affairs.General Directorate of Combating Desertification and Erosion Auburn University School of Forestry and Wildlife Sciences Kastamonu University Faculty of Forestry

Watershed disturbances caused by land use/land cover(LU/LC) change, intensive forestry practices, and other forms of watershed disturbance are known to negatively affect water quality, if best management practices(BMPs) are not present. Disturbances near or around headwaters where BMPs are absent or are inadequate may impact downstream water quality and stream ecology regardless of the presence of downstream BMPs. In this study, the recovery of two small forest-dominated watersheds(Ww and Ew) in Auburn, Alabama, USA, was monitored 6-years after a partial clearcut was done. The streamside management zone(SMZ) in Ww was also partially harvested shortly after the partial clearcut to improve its sediment trapping effectiveness over the long-term. The hydrology and sediment transport in these watersheds were expected to stabilize over this period, however, new disturbances in the headwaters of both watersheds changed the watershed dynamics. Streamflow and sediment load were examined over a15-month period from February 2014 to May 2015. The clearcut in Ww and Ew, and the partially harvested SMZ in Ww seemed to have recovered; however, substantial amount of sediment load were measured across all monitoring sites in both watersheds as a result of upstream disturbances. This study emphasizes the necessity of watershed management as a whole, and the importance of BMP applications within the entire watershed. It also highlights the fact that watershed management and BMP implementation is a dynamic process, thus, strategies and techniques need to be continuously adapted in response to environmental changes.

关键词： Headwater disturbances Best management practices sediment load Southeast USA

Key drivers of changes in the sediment loads of Chinese rivers discharging to the oceans

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International Journal of sediment Research 2021年第6期36卷 747-755页

作者： Cheng Liu Yun He Zhongwu Li Jia Chen Zhijing Li China Institute of Water Resources and Hydropower Research International Research and Training Center on Erosion and sedimentation College of Resources and Environmental Sciences Hunan Normal University Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources University of Chinese Academy of Sciences Changjiang River Scientific Research Institute

The magnitude and variation of the sediment loads transported by rivers have important implications for the functioning of river systems and changes in the sediment loads of rivers are driven by numerous factors. In this paper, the key drivers of changes in the sediment loads of the major rivers of China are identified by reviewing recent studies of changes in their sediment loads. Except for the Songhua River,which presents no clear tendency of change in runoff or sediment load, nearly all the major rivers of China are characterized by an apparent decline in annual sediment load. The total annual sediment load of major Chinese rivers transported to the coast decreased from 2.03 billion t/yr during the period 1955-1968 to 0.50 billion t/yr during the period 1997-2010. The primary drivers of changes in the sediment loads of the rivers are dam construction, implementation of soil and water conservation measures,catchment disturbance, agricultural practices, sand mining and climate change. Examples drawn from Chinese rivers are used to demonstrate the importance of these drivers. Construction of a large number of reservoirs in the Yangtze River basin represents the primary driver for the reduced sediment load of the Yangtze River. The implementation of soil and water conservation programmes is one of the key drivers for the sharp decline in the sediment load of the Yellow River. Catchment disturbance explains why the reduction of the sediment load of the Lancang-Mekong River at the Chiang Saen gauging station was much less than that at the Gajiu gauging station upstream. A reduction in sediment load resulting from the expansion of agricultural production may be the main driver for the reduced sediment load of the Huaihe River. The decrease in the sediment load of the Pearl River has been influenced by sand mining activities. Climate change is one of the key drivers responsible for the greatly reduced sediment load of the rivers in the Haihe River Basin.

关键词： sediment load Dam construction Soil and water conservation Catchment disturbance Sand mining Climate change

Exploration of the Mechanisms for the Low Sensitivity of Deposition Flux to Upstream sediment Reduction in the North Passage, Yangtze Estuary

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中国海洋工程:英文版 2023年第4期37卷 533-546页

作者： WANG Xiao-guang ZHANG Wei TONG Chao-feng LEI Zhi-yi QIN Jie JI Xiao-mei HUANG Rui The National Key Laboratory of Water Disaster Prevention Hohai UniversityNanjing 210098China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

Deltas are densely populated industrialized regions,and home to important ports and navigation *** to human interferences,the Yangtze Estuary has experienced a significant reduction in sediment load caused by the Three Gorges Dam(TGD),as well as adjustment to local morphodynamics by the Deep-water Navigation Channel(DNC).While the dramatic reduction in sediment triggers the increased channel erosion,the deposition flux of the DNC located at the estuary mouth has little *** explore the physical mechanism of this phenomenon,a two-dimensional model is used to establish the relationship between sediment load and the sediment budget of channels based on the bathymetry in *** results show that the tidal reach and the inner estuary have a negative sediment *** the seasonal characteristics of water and sediment fluxes become less obvious *** analysis shows that the influence of upstream sediment load on deposition flux decreases along the channel,with a transition from deposition to erosion occurring in the tidal *** the last-level bifurcation,the annual siltation of sediment in the North Passage(NP)decreases by 4.5%with low *** is attributed to the reduction of sediment load partially mitigated by riverbed erosion and cascade *** addition,the lateral sediment supply,which accounts for 68%of the sediment input in the NP,is ***,this study strengthens the understanding of the relationship between sediment load and artificially deepened systems,thus allowing for better management of estuarine sediment and navigation channel.

关键词： delta navigation channel sediment load erosion and deposition sediment budget Yangtze Estuary

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Response of delta sedimentary system to variation of water and sediment in the Yellow River over past six decades

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Journal of Geographical Sciences 2010年第4期20卷 613-627页

作者： PENG Jun CHEN Shenliang State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062China

In order to find out the variation process of water-sediment and its effect on the Yellow River Delta, the water discharge and sediment load at Lijin from 1950 to 2007 and the decrease of water discharge and sediment load in the Yellow River Basin caused by human disturbances were analyzed by means of statistics. It was shown that the water discharge and sediment load into the sea were decreasing from 1950 to 2007 with serious fluctuation. The human activities were the main cause for decrease of water discharge and sediment load into the sea. From 1950 to 2005, the average annual reduction of water discharge and sediment load by means of water-soil conservation practices were 2.02×10^9 m^3 and 3.41×10^8 t respectively, and the average annual volume by water abstraction for industry and agriculture were 2.52×10^10 m^3 and 2.42×10^8 t respectively. The average sediment trapped by Sanmenxia Reservoir was 1.45×10^8 t from 1960 to 2007, and the average sediment retention of Xiaolangdi Reservoir was 2.398×10^8t from 1997 to 2007. Compared to the data records at Huanyuankou, the water discharge and sediment load into the sea decreased with siltation in the lower reaches and increased with scouring in the lower reaches. The coastline near river mouth extended and the delta area increased when the ratio of accumulative sediment load and accumulative water discharge into the sea （SSCT） is 25.4-26.0 kg/m^3 in different time periods. However, the sharp decrease of water discharge and sediment load into the sea in recent years, especially the Yellow River into the sea at Qing 8, the entire Yellow River Delta has turned into erosion from siltation, and the time for a reversal of the state was about 1997.

关键词： Yellow River water discharge sediment load human activities delta

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sediment-loading Processes in a Forested Catchment: Modeling and Observations

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Open Journal of Modern Hydrology 2023年第2期13卷 94-113页

作者： Md. Motaleb Hossain Kazuhisa A. Chikita Yoshitaka Sakata Department of Mathematics Faculty of Science University of Dhaka Dhaka Bangladesh Arctic Research Center Hokkaido University Sapporo Japan Faculty of Geosciences and Civil Engineering Institute of Science and Engineering Kanazawa University Kanazawa Japan

In order to investigate sediment-loading processes in a catchment, the daily time series of river discharge and sediment load were applied to a semi-distributed model, the Soil and Water Assessment Tool (SWAT). The time series of discharge and sediment load were obtained by monitoring the river stage and water turbidity of the Oikamanai River, Hokkaido, Japan, in the rainfall season (April-November) of 2011-2014. The catchment is forested (ca 90% area) but underlain by the Neogene sedimentary rocks with currently active faults and forest soils with tephra layers, which tend to frequently produce slope failure such as landslide and bank collapse by rainfall or snowmelt. The water turbidity, T, in ppm was converted into suspended sediment concentration, SSC, in g/L by applying the linear relationship between T and SSC. The acquisition of the time series of discharge, Q (m3/s) and sediment load, L (=Q·SSC in g/s) of the river allowed us to distinguish the fluvial sediment transport, accompanied by slope failure in the upstream, from that under no slope failure. The SWAT was used to simulate soil erosion and identify the region prone to the soil erosion in the Oikamanai River basin. The model’s results showed a satisfactory agreement between daily observed and simulated sediment load as indicated by the high Nash-Sutcliffe efficiency. This evidences that the upper mountainous region of the catchment provides a main sediment source, accompanied by slope failure.

关键词： SWAT Slope Failure Landslide Bank Collapse Forested Catchment sediment load