ENVIRONMENTAL PERSPECTIVE：BENEFICIAL AND ADVERSE EFFECTS OF THREE GORGES PROZECT

ＥＮＶＩＲＯＮＭＥＮＴＡＬＰＥＲＳＰＥＣＴＩＶＥ：ＢＥＮＥＦＩＣＩＡＬＡＮＤＡＤＶＥＲＳＥＥＦＦＥＣＴＳＯＦＴＨＲＥＥＧＯＲＧＥＳＰＲＯＺＥＣＴＦＡＮＧＺｉｙｕｎ１．ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＴｈｒｅｅＧｏｒｇｅｓＰｒｏｊｅｃｔ（ＴＧＰ）ｉｓａｖ...     

EROSION OF MATERIAL IN GROUND SURFACE AND SEDIMENT YIELD IN THE UPPER YANGTZE RIVER

ＥＲＯＳＩＯＮＯＦＭＡＴＥＲＩＡＬＩＮＧＲＯＵＮＤＳＵＲＦＡＣＥＡＮＤＳＥＤＩＭＥＮＴＹＩＥＬＤＩＮＴＨＥＵＰＰＥＲＹＡＮＧＴＺＥＲＩＶＥＲＬＩＵＹｉａｎｄＺＨＡＮＧＰｉｎｇＡｂｓｔｒａｃｔ：ＣｏｎＳｉｄｅｒｉｎｇｔｈｅｅｒｏｓｉｏｎｏｆｇｒｏｕｎｄ...     

EFFECT OF DIVERSION ON THE LOWER YELLOW RIVER

ＥＦＦＥＣＴＯＦＤＩＶＥＲＳＩＯＮＯＮＴＨＥＬＯＷＥＲＹＥＬＬＯＷＲＩＶＥＲ￥ＷａｎｇＹａｎ－ｇｕｉａｎｄＬｉＸｉ－ｘｉａ（Ｅｎｇｉｎｅｅｒ，ＳｅｄｉｍｅｎｔＤｅｐｔｏｆＩｎｓｔｉｔｕｔｅｏｆＷａｔｅｒＣｏｎｓｅｒｖａｎｃｙａｎｄＨｙｄｒｏｅｌｃｔｒ...     

ON THE REDUCTION OF WATER AND SEDIMENT YIELD OF THE YELLOW RIVER IN LATE YEARS

ＯＮＴＨＥＲＥＤＵＣＴＩＯＮＯＦＷＡＴＥＲＡＮＤＳＥＤＩＭＥＮＴＹＩＥＬＤＯＦＴＨＥＹＥＬＬＯＷＲＩＶＥＲＩＮＬＡＴＥＹＥＡＲＳＧＵＷｅｎｓｈｕＡｂｓｔｒａｃｔ：ＴｈｅｒｅｃｏｒｄｅｄｈｙｄｒｏｌｏｇｉｃｄａｔａｏｆｔｈｅＹｅｌｌｏｗＲｉｖｅｒｉｎｄ...     

ON SOME ASPECTS OF DISTORTED RIVER MODEL WITH MOVABLE BED

ＯＮＳＯＭＥＡＳＰＥＣＴＳＯＦＤＩＳＴＯＲＴＥＤＲＩＶＥＲＭＯＤＥＬＷＩＴＨＭＯＶＡＢＬＥＢＥＤＺＨＵＰｅｎｇｃｈｅｎｇＩ．ＩＮＴＲＯＤＵＣＴＩＯＮＧｅｏｍｅｔｒｉｃａｌｓｉｍｉｌａｒｉｔｙｉｓｔｈｅｂａｓｉｓｏｆｈｙｄｒａｕｌｉｃｍｏｄｅｌｔｅｓｔ...     

RESEARCHES ON ENVIRONMENTAL CHANGES AND WATER AND SEDEMENT TRANSPORT OF THE YELLOW RIVER BASIN

ＲＥＳＥＡＲＣＨＥＳＯＮＥＮＶＩＲＯＮＭＥＮＴＡＬＣＨＡＮＧＥＳＡＮＤＷＡＴＥＲＡＮＳＥＤＥＭＥＮＴＴＲＡＮＳＰＯＲＴＯＦＴＨＥＹＥＬＬＯＷＲＩＶＥＲＢＡＳＩＮＹＥＱｉｎｇｃｈａｏ２Ｉ．ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍａｊｏｒｐｒｏｊｅｃｔ″Ｒｅｓｅ...     

UNCERTAINTY AND SENSITIVITY ANALYSES OF SEDIMENT TRANSPORT FORMULAS

ＵＮＣＥＲＴＡＩＮＴＹＡＮＤＳＥＮＳＩＴＩＶＩＴＹＡＮＡＬＹＳＥＳＯＦＳＥＤＩＭＥＮＴＴＲＡＮＳＰＯＲＴＦＯＲＭＵＬＡＳＫｅｈＣｈｉａＹＥＨ１ａｎｄＳｅｎＬｏｎｇＤＥＮＧ２ＡＢＳＴＲＡＣＴＩｎｖｉｅｗｏｆｔｈｅｒａｎｄｏｍｃｈａｒａｃｔｅｒｉｓｔ...     

ANALYSIS ON THE SENSITIVITY OF THE FLUVIAL PROCESS IN ALLUVIAL RIVER

ＡＮＡＬＹＳＩＳＯＮＴＨＥＳＥＮＳＩＴＩＶＩＴＹＯＦＴＨＥＦＬＵＶＩＡＬＰＲＯＣＥＳＳＩＮＡＬＬＵＶＩＡＬＲＩＶＥＲ￥ＣＡＯＷｃｎｈｏｎｇａｎｄＺＨＡＮＧＱｉｓｈｕｎ（ＲｅｓｅａｒｃｈＥｎｇｉｎｅｅｒ，ＩｎｓｔｉｔｕｔｅｏｆＷａｔｅｒＣｏｎｓｅｒｖａ...     

MATHEMATICAL MODEL OF OVERLAND FLOW AND MECHANISM OF SOIL CONSERVATION FOR FORESTED STEEP HILLSLOPE－－（II）Mechanism of Soil Conservation Over Steep Hillslope

ＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＯＦＯＶＥＲＬＡＮＤＦＬＯＷＡＮＤＭＥＣＨＡＮＩＳＭＯＦＳＯＩＬＣＯＮＳＥＲＶＡＴＩＯＮＦＯＲＦＯＲＥＳＴＥＤＳＴＥＥＰＨＩＬＬＳＬＯＰＥ－－（ＩＩ）ＭｅｃｈａｎｉｓｍｏｆＳｏｉｌＣｏｎｓｅｒｖａｔｉｏｎＯｖｅｒＳｔ...     

A SIMPLIFIED APPROACH TO MODELING 3D SEDIMENT-LADEN TURBULENT FLOWS

ＡＳＩＭＰＬＩＦＩＥＤＡＰＰＲＯＡＣＨＴＯＭＯＤＥＬＩＮＧ３ＤＳＥＤＩＭＥＮＴ－ＬＡＤＥＮＴＵＲＢＵＬＥＮＴＦＬＯＷＳＤｏｎｇｈｕｏＺＨＯＵａｎｄＳａｍＳ．Ｙ．ＷＡＮＧＡｂｓｔｒａｃｔ：Ａ３－ｄｎｕｍｅｒｉｃａｌｍｏｄｅｌｆｏｒｓｉｍｕｌａｔｉｎｇｓ...     

DEFORMATION OF RIVER BED AND THE CHARACTERISTICS OF SEDIMENT TRANSPORT DURING HYPER-CONCENTRATED FLOOD IN THE YELLOW RIVER

LINTRODUCTIONTheYellowforeriswellknownasaheavilysilt-caacingriverintheworld.Haaer-concentratedfloodsoftenoccurinitsmasterstemandaswellasthetriblltaries.ThecharacteristicsofdeformationandsedimellttranSportdifferfromreachtOreach.Duetohighsedimelltconcelltration,StrongfluvialactionandthenatUreofunSteadysedimenttranSPOrt,problemsandabnormalphenomenonareoflencreated.ThelaterbringinimpacttOnoodcontrolOfthelowerreach.Thus,itishelpfultoenhancetheunderstandingofthemotionlawsOfhaer-concentrat…     

INFLUENCE OF THE UPSTREAM RESERVOIRS ON THE ADJUSTMENT OF DOWNSTREAM ALLUVIAL CHANNEL

I. INTRODUCTIONThe Yellow River is a heavily sediment--laden river. The sediment load of the Yellow River ranks the first in the world while its annual runoff is only of medium size. Toharness the river, it is necessary to build reservoirs for regulating runoff to meet the demands of economic development. Since the founding of PRC in 1949, I S4 large and medium--sized reservoirs have been constructed on the main stem and the tributaries with atotal storage capacity of 84.5 billion m3.…     

SEDIMENTATION PROBLEMS IN THE ACCESS CHANNELS OF THE GEZHOUBA NAVIGATION LOCKS

Sedimentation problems in the access channels of the Gezhouba Navigation Locks at the Third Channel, which is of great importance for the navigation are discussed in this paper:1) the cause of deposition in the access channel, 2) effects of the deposit--reducing embankment and sediment sluices and 3) the relation between the sediment deposition at the Third Channel and the sediment discharge of the Yangtze River. Analyzing a four years' field data of sounding records with respect to the lock operation, it can be seen that the flood release through the navigation channel resulted in severe deposition, especially the sediment deposits induced by eddy current are difficult to be cleared off by flushing and jeopardize the working conditions of the lock operation. It is obvious that the flood release through the navigation channel should be minimized. In order to reduce the sediment deposits caused by eddy current attempts should be made to adjust the alignment of the boundaries and layout of the entrance of access channels.     

NUMERICAL SIMULATION OF SEDIMENT TRANSPORT IN ALLUVIAL RIVER WITH FLOODPLAINS

1 INTRODUCTION The transport of sediment in rivers with active floodplains is a two-dimensional process because the main channel and the floodplain can have very different transport capacities. Therefore, two-dimensional (2D) models are often used to simulate the streamwise and transverse variations of sediment erosion and deposition. Many 2D numerical models have been presented to simulate sediment transport in floodplains (James, 1985; Pizzuto, 1987; Howard, 1992; Nicholas and Walli…     

DEFORMATION AND ROUGHNESS CHANGES OF THE MAIN CHANNEL AND FLOODPLAIN IN FLOOD EVENTS (CASE STUDY )

LINTRODUCTIONAsfear7specificsurveyshavebeenmadeonthemorphologicalbehavioroftheHuaihefox'erinthepast.Someinformationofbeddeformationduringfloodprocesshavebeenobtained.Beingrelativelystable,theHuaihehiverusedtobeineptlytreatedas"fixedbed".Fortunately,tilehydrometricalstationsweredenselydistributedalongtheHuaihehiverinthe1950s,andthevelocitylareamethodwasusedforthedeterminationofdischarge.Themeasurementsofdischargearelistedin"TheDischargeMeasurementsTable"intheHydrologicalYearbooks.Sinc…     

Morphology of Red Creek,Wyoming, an arid-region anastomosing channel system

Red Creek, in the Red Desert area of the Great Divide Basin, Wyoming, is an arid-region anastomosing stream. The narrow, deep, and sinuous main channel is flanked by anastomosing flood channels, or anabranches. Most anabranches are initiated at meander bends. The primary mechanism of anabranch initiation is avulsion during overbank floods. Anabranch enlargement occurs by headward erosion. Anabranches act as distributary channels during floods, when water and sediment from overbank flows are transported to and deposited on the floodplain via the anabranches. During periods of low discharges, the anabranches act as tributaries to the main channel, transporting runoff from the floodplain and surrounding hillslopes to the main channel of Red Creek. Aggradation is occurring in the main channel and on the floodplain throughout the study reach. Infilling of the main channel occurs primarily by lateral accretion, while the floodplain accretes vertically through deposition of overbank sediment from the main channel and anabranches. Infilling of the main channel may cause avulsion of the main channel into an anabranch. The abandoned main channel segment may then fill completely or act as an anabranch. Because lateral migration of channels is inhibited by the high cohesion of the silt and clay channel sediment, periodic avulsion is the primary form of lateral mobility in the system.     

IMPACTS OF FLOOD EVENTS IN COARSE SEDIMENT-PRODUCING AREAS ON CHANNEL SILTATION AND FLUVIAL PROCESS OF THE LOWER YELLOW RIVER

The method of multiple regression is used to analyze the influences of flood events from the coarse sediment producing areas on the channel siltation and fluvial process of the lower Yellow River based on the flood events from 1950 to 1985. The results showed that the flood events from the coarse sediment producing areas carry larger amounts of sediment load and coarser particle sizes than from other source areas, which increases deposition in the lower river channel. And there exist good correlations between channel siltation of the lower reaches of the Yellow River and the coming water and sediment of flood events from the coarse sediment producing areas. Through these correlations, the amounts of sediment deposition in the lower river channel could be roughly estimated based on the runoff and sediment load of flood events from the coarse sediment producing areas. The sediment deposition caused the fluvial process. There exists a complex response of channel form change to the coming water and sediment load of flood events from the coarse sediment producing areas. When the sediment concentration is smaller than 200kg/m3, the ratio between wide-depth ratio after flood and wide-depth ratio before flood((B/h)a / (B/h)b) will increase with the increase of the maximum sediment concentration; when the sediment concentration is near 200kg/m3, (B/h)a / (B/h)b reaches the maximum value; and when the sediment concentration reaches the limits of hyperconcentrated flow, (B/h)a / (B/h)b will decrease with the increase of the maximum sediment concentration. Generally, flood events from the coarse sediment producing areas made channel form of the lower Yellow River deeper and narrower, but a large amount of sediment deposition simultaneously occurs. So, the impacts of flood events from the coarse sediment producing areas on the channel of the lower Yellow River are lessened.     

Sediment transport trends and cross-sectional stability of a lagoonal tidal inlet on the Central Coast of Vietnam

Lagoonal tidal inlets are a typical morphology of the Central Coast of Vietnam. Recently, navigation channels in these inlets have become increasingly threatened by siltation. This study analyses the relations between sediment distribution and transport trends (using the technique of Sediment Trend Analysis-STA■) in the lagoonal system of the De Gi inlet and then proposes appropriate countermeasures against sand deposition in the navigation channel. The STA identified three types of transport trends in the De Gi inlet, namely dynamic equilibrium, net accretion, and net erosion. Processes associated with the tidal prism have resulted in trends of sediment transport and deposition across the flood and ebb tidal shoals, which maintain a present cross-sectional area of about 1000m^2. However, longshore sediment transport from north to south resulting from northeast waves cause additional sand deposition in the channel. In addition, the effects of refraction associated with a nearby headland and jetty also increase sedimentation. These processes provide the main reasons for sediment deposition in the De Gi inlet. Short term and regular dredging helps to maintain the navigation channel. A system comprised of three jetties (north, south, and weir) is necessary to ensure the longterm cross-sectional stability of the navigation channel.     

PREDICTION OF IMPACT OF THE THREE GORGES PROJECT ON ESTUARY BEACH OF THE YANGTZE RIVER

ＰＲＥＤＩＣＴＩＯＮＯＦＩＭＰＡＣＴＯＦＴＨＥＴＨＲＥＥＧＯＲＧＥＳＰＲＯＪＥＣＴＯＮＥＳＴＵＡＲＹＢＥＡＣＨＯＦＴＨＥＹＡＮＧＴＺＥＲＩＶＥＲＷｅｉｂｉｎｇＦＥＮＧ１ＹｉｇａｎｇＷＡＮＧ２ａｎｄＸｉｕｃｈｅｎｇＺＨＯＮＧ３ＡＢＳＴＲＡＣＴＡｌｔｈｏ...     

THE 1998 FLOOD OF THE YANGTZE RIVER

1INTRODUCTIONDuringthefloodseasonof1998,anothercatastrophicfloodoccurredinthemiddleandlowerYangtzeRiverfollowingthecatastrophicfloodin1954.Ascomparedwiththe54flood,the1998floodwascharacterizedbythefactsthatthedurationofthehighwaterstagewasmuchlonger,thefloodcontrolwasmuchmoredifficult,andthetotalmanpowerandmaterialresourcesexpelldedintilefloodfightingweremuchmoreenormous.TOsummarizetheexperienceandlessonsfromthefloodissignificanttotilehydraulicengineeringandfloodcontroloftheYangtzeRiver.…