EFFECTS OF SEDIMENT GRADATION ON THE GEOMETRY OF RIVER DELTAS

l INTRODUCTlONIn this study, formation of alluvial deltas was treated as a river-dominated type of topograPhy process,caused simply by sediment deposition from a channel into a wide basin. The influences of waves, tides,and density differences related to coastal effects were excluded. There have been numerous experimentalstUdies on river delta problems. For examPle, Shieh et al. (1988, 1997) used coarse sediment asexperimental material and revealed the development and the geometric simil…     

SEDIMENT CARRYING CAPACITY OF SEA CURRENT AND THE TRAINING OF THE YELLOW RIVER MOUTH

1INTRODUCTIONTheYellowRivercarries1.6billiontonsofsedanmentload,rankedthefirstintheworld.Sedimentationinthelowerreachesresultedinfrequentlyshiftoftherivercourses.ThroughoutthehistoryofChina,theYellowRiverhasbeenassociatedwithfloodsandfamine,earningtherivername"China'ssorrow"(Hu,l996).Instabilityoftheriverchannel,especiallythedeltachannel,restraintstheeconomicdevelopmentofthearea.TheDongyingmunicipalgovernment,theShenliOilCorporationandtheYellowRiverMouthManagementBureauofYRCC(Yel…     

PRINCIPLES OF RIVER TRAINING AND MANAGEMENT

River regulation and river training have been performed for various purposes and negative effects have been shown in numerous cases. In some cases the negative effects are so serious that humans have to consider to "renaturalize" the regulated rivers. Only by using the strategy of integrated river management the diverse river uses and natural fluvial processes and ecological systems may be harmonized. Based on analysis of case studies and data collected from literatures this paper presents the concept of integrated river management and four principles of river training. The integrated river management comprises: 1) taking the watershed, upper stream basin including the tributaries, middle and lower reaches and the estuary as an integrated entity in the planning, design and management; and 2) mitigating or controlling the negative impacts on hydrology, erosion and sedimentation, fluvial processes, land use and river use, environment and ecology while in achieving economic benefit from water resources development, flood safety management and hydropower exploitation. River training and management should be in accordance with the four principles: 1) extending the duration of river water flowing on the continent, which may be achieved by extending the river course or reducing the flow velocity; 2) controlling various patterns of erosions and reducing the sediment transportation in the rivers; 3) increasing the diversity of habitat and enhancing the connectivity between the river and riparian waters; and 4) restoring natural landscapes.     

EFFECT OF SUSPENDED SEDIMENT ON THE TRANSPORT AND TRANSFORMATION OF 4 - NITROCHLOROBENZENE IN THE YELLOW RIVER

I.INTaonUCTIOXP-NCBisatoxiccompoundwhichmaycausecarcinogenicoramutation.NowthetransPOrtandtransformationofthiskindOfsubstanceinnaturalwaterbodyisthefocusofresearchofscientistsintheworld.ThroughthestudytherelationshipbetweennonionicorganiccomPOunds,suchasP-NCB,andsuspendedsedimentisfoundtobeveryclOSe,suspendedsedimentareload-supPOrtingofmovementandmediateagentofreactionofP-NCBinwater.TheYellowRiverisheavilysediment-laidenriverintheworld.Sometimesthesuspendedsedimentcanbeupto200kgpe…     

EFFECTS OF WATERSHED MANAGEMENT ON THE REDUCTION OF SEDIMENT AND RUNOFF IN THE JIALING RIVER,CHINA

The Three Gorges Project is one of the largest hydro-projects in the world and has drawn many debates inside China and abroad. The major concern is that sediment load from the river basin may eventually fail the functions of the project for flood control and power generation. To reduce sedimentation in the reservoir, watershed management has been adopted. However, there is limited information regarding the effectiveness of various control measures such as terracing and afforestation on a watershed scale. The Jialing River, a main tributary of the Yangtze River, contributes approximately 25% of the total sediment load in the main river but only represents 8% of the whole basin area. There have been various land use patterns and extensive human activities for thousands of years in the Jialing River watershed. Based on analysis of the major factors affecting erosion in the Jialing River watershed, the main watershed management strategies (afforestation, farming and engineering practice) are illustrated, and their effects on the reduction of sediment and runoff are studied in detail. The sediment budget of the watershed shows that 1/3 of the sediment yield is trapped by the erosion control measures (afforestation and farming) on the slope, 1/3 is trapped by the reservoirs, ponds and dams within the watershed, and only about 1/3 is transported into the Yangtze River, which will affect the Three Gorges Project.     

RESUSPENSION OF FINE SEDIMENT IN RESERVOIRS - A CASE STUDY OF THE LOWER INN RIVER

1 THE LOWhR unR INNThe Inn river has its source in the alPine region of the GraubUnden canton of Switzerand. ThecatChment area of about 260(X} kIn2 includes mountains of the central Alpes up to 40(X) m. The river runs5l7 km thrOugh the countries of SwitZerand, Austria and Germany on itS way into the Danube mver. Thedischarge of the river at its mouth in the city of Passau is mainly infiuenced by the snow melt in themountainous catchment area and vches between apProx. 200 m3ls durin…     

LONG TERM EFFECTS OF REHABILITATION MEASURES ON BED LOAD TRANSPORT AT THE SALZACH RIVER

1 BASIC PROBLEMFlood protecton, sPreaing of settlements and occuPatin Of river valleys were maor reasons to damand lindt rivers throughout Europe in the ndd 19th century. Engineers of those days often knew very wellabout the effects of their plannings: shortening the river length would accelerat the now and thusencourage the erosion into the river's sedAnents. Two vital advanages could be obtalned from that kindof constrUction, landuse of the fOrmer flood plains on the one and increasin…     

A STUDY ON THE WARPING NEAR IRRIGATION HEADWORK OF THE LOWER REACH OF YELLOW RIVER

IINTRODUCTIONTheYellowRiverisfamousforitsttemendousamountofsedimenttransport.Basedonastatisticaldataanalysis,along-timeaverageannualof1.6billiontonsofsedimententerstheLowerYellowRiver,inwhich400milliontonsaredepositedintherivercharmel.Thesedimentdepositioncausesavapidriseofthebedelevation.Withahistoricalevollltionoftheriverchanges,aso-called"suspendedriver"graduallyformed.UPtonow,thegroundleveloftheareaolltsidetheriverleveesismuchlowerthanthewaterlevelintheriver.Thissituationbringsanex…     

COMPUTATIONAL SIMULATION OF RIVER SEDIMENTATION AND MORPHOLOGY - A REVIEW OF THE STATE OF THE ART

In this paper, the state-of-the-art computational simulation technologies for river sedimentation and morphology are comprehensively reviewed. Emphasis is on computational modelling, which includes mathematical modelling equations and closures, numerical solution methods, verification and validation, model integration, and applications. Several important areas of future research are recommended.     

珠江三角洲断裂构造最新活动性研究

根据在珠江三角洲及其周围地区测得的热释光年龄和第四系沉积物的分布等资料，分析讨论了断裂的最新活动性。自晚更新世以来，陈三角洲外围几条主要的北东向断裂的局部地段以外，基本上处于比较稳定的状态。晚更新世一全新世早期有过明显活动的断裂有狮子洋东西两侧的北西向断裂，近南北向的崖门断裂和北东向的古劳－广州断裂。近东西向的瘦狗岭断裂新世亦有过活动。     

武威盆地晚更新世河流阶地变形与新构造活动

根据武威盆地 7条河流的阶地测量资料和测年数据探讨了河流阶地变形与新构造活动的关系。河流阶地的变形特征反映出新构造活动的方式 ,断层活动以逆冲为主 ,河流阶地的错断状况表明活动断层活动的次数 ,盆地西部活动至少有 7次 ,东部活动至少有 5次 ;同时可表明断层活动的幅度与强度 ,以及不同时期活动强烈区具有迁移变化的特点。武威盆地晚更新世以来发育的第四纪断层主要有 3条 ,各条断裂活动次数、强度不尽相同 ,以山前断裂活动最为强烈 ,至今活动仍未停息。 6 0ka前后西部活动强烈 ,2 0ka以来东强西弱     

长江口以东海域MS6.1地震前的地倾斜异常

１９９６年１１月９日长江口以东海域发生ＭＳ６．１地震,震前距震中２９０ｋｍ的湖州地倾斜台观测到中期异常和短临异常,距震中２４０ｋｍ的宁波地倾斜台也观测到短临异常．这里简单介绍了地倾斜异常的演化过程以及地震三要素的预测．震前我们进行了中短期预报,取得较好效果,但没有提交短临预报意见,这主要是由于短临异常出现较晚和台站资料报送不及时所致．