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

2.
1INTRODUCTIONTileillinoisRiver,oneofthemajortributariestotheMississippiRiverinthecentralUnitedStates,hasadrainageareaof75,156kmZthatcoversportionsof1llinois,Indiana,andWisconsin(Figllre1).Asaresultofrepeatedlevelingbyglaciers,mostofthe1llinoisRiverwatershedisflatandcoveredwithfineloesssoil,makingitoneofthebestagriculturalregionsinNorthAmerica.Morethan80percentoftheIllinoisRiverbasinispresentlyusedforagricultUralpurposes.IllinoisagricultUrestartedtoexpandveryrapidlyinthe19thcentury,g…  相似文献   

3.
1. INTROOrCTIOXThe upper Tisza in Hungary is a sand bed alluvial river. presenting several river training problems. In order to solve these problems first the laws of free river--bed evolution must be clarified thenthe effects of existing river training s…  相似文献   

4.
1 INTRODUCTION Soil erosion is serious in Western China. With the implementation of a development strategy for western China, soil and water conservation and ecological restoration in western China earn more attention because economic development requires parallel efforts on ecological restoration. To protect the ecology of the upper reaches of the Yangtze River, integrated management of sediment and ecological restoration are being conducted in Sichuan Province. The Yufeng Watershed…  相似文献   

5.
1INTRODUCTIONTheBrahmaputraRiveroriginatesfromtheJimayanzhongglacieratthenorthfootoftheHimalayaMountainsinSouthTibet,China.I...  相似文献   

6.
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.  相似文献   

7.
SEDIMENT QUALITY AND ECOLOGICAL RISK OF THE RIVER MOUTHS AROUND BOHAI BAY   总被引:1,自引:0,他引:1  
1 INTRODUCTION Bohai Bay suffers from eutrophication and red tide has been occurring frequently since the 1990s. The water pollution is caused by pollutants originating inland that account for 87% of all pollutants entering the bay. More than 40 rivers flow into the bay carrying 95% of the total pollutants and nutrients from inland sources (Zhao and Kong, 2000). Among these rivers, the Yellow, Liaohe, Luanhe, Haihe and Jiyun Rivers are the largest, which carry 1.3 109 t of sediment lo…  相似文献   

8.
lINTR0DUCTIONSoiler0si0ncanbeaseriousproblemonsl0pinguplands0fthes0uthemUnitedStatesthatareintensivelycr0pped.Conservati0nprovisionsofthel985U.S.FarmBillmandateddevelopmentofaconservati0nplanonhighlyer0diblelands.Researchwasinitiatedinl9870na28-haareaattheA-E.Nels0nFarrninn0rthernMississippit0determineiftheconservati0nprovisionscouldbeachievedwhileprofitablygr0wingrowcropsincludingcott0n(GosSyPiumhirsutumL.),soybean(GlyciDemax(L.)Merr.),sorghum(SOrghumbicolor(L.)Moench),c0rn(Zeam…  相似文献   

9.
Water and sediment qualities are studied by analyzing samples taking from the mouths of the Haihe, Duliujian, New Ziya and Beipai rivers in the Haihe river basin in north China in 2005 and 2001, in order to find the changes of water and sediment pollutions. The concentrations of heavy metals, arsenic, total nitrogen (TN) and total phosphorus (TP) are analyzed and results have been compared for the two times. The in-situ measurement for Dissolved Oxygen (DO) and Sediment Oxygen Demand (SOD) rates were carried at the Haihe and Duliujian river mouths in 2006. The results show that the waters of the 4 river mouths are still seriously polluted, though much improved in the case of the Haihe and Duliujian rivers. The main pollutants are TP and TN in the New Ziya and Beipai rivers and mercury (Hg) at all 4 river mouths. Compared with those in 2001, the concentrations of almost all metals and arsenic in the 4 river mouths have decreased. Water quality at Haihe and Duliujian shows an improving trend, while the water quality at Beipai is similar to that of 2001. In contrast, water at the New Ziya river mouth is more severely polluted. The sediments in the 4 river mouths are not seriously polluted by heavy metals but are polluted by nitrogen and phosphorus. Most of the pollutant contents in the sediments show little change between 2001 and 2005. The in-situ DO and SOD measurement shows that the waters at the Haihe river mouth is in the state of oxygen depletion, and SOD is important consumer of DO at the river mouths. The overall analysis shows that increasing water pollution and eutrophication in waters far from cities are ongoing causes of concern.  相似文献   

10.
LINTRODUCTIONTheYellowforeriswellknownasaheavilysilt-caacingriverintheworld.Haaer-concentratedfloodsoftenoccurinitsmasterstemandaswellasthetriblltaries.ThecharacteristicsofdeformationandsedimellttranSportdifferfromreachtOreach.Duetohighsedimelltconcelltration,StrongfluvialactionandthenatUreofunSteadysedimenttranSPOrt,problemsandabnormalphenomenonareoflencreated.ThelaterbringinimpacttOnoodcontrolOfthelowerreach.Thus,itishelpfultoenhancetheunderstandingofthemotionlawsOfhaer-concentrat…  相似文献   

11.
LRESEarCHACTIVITIESCharaCtCriedcofunlinedalluvialriVersisthe~linteractionbettVeenwaterflowandmovableriVerbed.Sedimenttransport,bedresistanceandriVermorphologydecisivelydependontheflowconditionsandviceversathesefactorsgovernthehydraulicprocesses.EVenundersimplifiedconditions,e.g.inlaboratorytests,theseillteractionsareeXtremelycomplexandrelldsraliZationmakesengineeringproblemsevenmored~.TomaketheseprocessesmoreunderstandablecomprehensiVeresearchprojectswereconductedatseveralGermanuniv…  相似文献   

12.
康琴  阿成业 《高原地震》2007,19(3):54-58
简述了长江源区自然地理和生态地质环境特征,分析了环境恶化的主要原因及防治对策。  相似文献   

13.
对我国地震队伍的现状,特别是对新一代学科带头人成长中存在的问题进行了深入的分析,论述了加速培养新一代年青的学科带头人,是关系到地震科技事业前途的大事,必须从战略的高度来认识这一问题的重要意义,进而提出加速培养造就年青学科带头人队伍的建议。  相似文献   

14.
15.
1 BACKGROUND The Illinois River is the most significant river in the state of Illinois. The river drains nearly half of the state and has a drainage area of 28,906 mi2 (74,867 km2). Except for about a 4,000 mi2 (10,360 km2) area in Indiana and Wisconsin, the watershed is located in Illinois (see Fig. 1). The watershed contains the drainage basins of several of the state's significant rivers such as the Sangamon, LaMoine, Spoon, Mackinaw, Vermilion, Fox, Kankakee, and Des Plaines Ri…  相似文献   

16.
I INTRODUCTIONThe volume and regime of sediment load are the most important factors, which are responsible for theformation, direction and deformation rate of the river channels. Despite the long history of study anddevelopment of sediment load calculation methodology, there are still numerous problems that remain tobe solved such as river pattern and sediment movement and so on (Wang et al, 1997).In this respect, the comparative analysis of sediment load and river channel processes of la…  相似文献   

17.
1INTRODUCTIONInaneforttoprovideadequatefoodandfibreforthetemingpopulation,mostcountriesinthetropicshaveopeneduptheirprotectiv...  相似文献   

18.
RANGE SURVEY OF DEPOSITION IN THE LOWER YELLOW RIVER   总被引:3,自引:0,他引:3  
1 GENERAL DESCRIPTION The Yellow River, running out of the gorges below the Sanmenxia (SMX) and Xiaolangdi (XLD) reservoirs, flows through the vast North China alluvial plain, and finally empties into the Bohai Sea (Fig. 1). The upper part of the Lower Yellow River (LYR), nearly 400 km in length, is confined by levees along both banks. The river wanders with a shallow main channel and broad flood plains. The lower part has a relatively narrow and deep main channel and less b…  相似文献   

19.
对1986年以来地震系统管理干部(处级以上)的培训现状进行了调研、分析和评估,从理论与实际两个方面进行了探讨,为地震系统今后开展管理科学培训提出可行性的决策依据。  相似文献   

20.
The characteristics of water flow and sediment transport in a typical meandering and island-braided reach of the middle Yangtze River is investigated using a two-dimensional (2D) mathematical model. The major problems studied in the paper include the carrying capacity for suspended load, the incipient velocity and transport formula of non-uniform sediment, the thickness of the mixed layer on the riverbed, and the partitioning of bed load and suspended load. The model parameters are calibrated using extensive field data. Water surface profiles, distribution of flow velocities, riverbed deformation are verified with site measurements. The model is applied to a meandering and island-braided section of the Wakouzi-Majiazui reach in the middle Yangtze River, which is about 200 km downstream from the Three Gorges Dam, to study the training scheme of the navigation channels. The model predicts the processes of sediment deposition and fiver bed erosion, changes of flow stage and navigation conditions for the first 20 years of impoundment of the Three Gorges Project.  相似文献   

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