简介:TheYellowRiveristhecradleofChina.Ithadlongbeenthecenterofpolitics,economicsandcultureofChinainhistory.LargecoverageflooddisasteroccurredfrequentlyintheYellowRiverbasinandthelosseswereoftenheavy.Thus,theYellowRiverisalsoconsideredastheserioushiddendangerofChina.SincethefoundingofnewChina,structuralandnon-structuralsystemsoffloodcontrolhavebeenestablishedbasically.Tremendoussuccesseshavebeenmadeonfloodcontrol.Intothe21century,floodcontrolstandardoftheLowerYellowRiverhasbeenincreasedsignificantlywiththeoperationoftheXiaolangdiReservoir.However,problemsoftheYellowRiverarecomplicatedandthetasksforsolvingtheseproblemsarearduous.Particularly,thesedimentationproblemcan'tbesolvedcompletelyinthenearfuture.Thesituationof"suspendedriver"andthreatoffloodwilllongexist.Therefore,supportedbyrapidsocialandeconomicaldevelopmentofthenationandreliedonadvancedtechnology,thefloodcontrolsystemshallbeperfected.Meantime,studyoftheYellowRivershallbeenhancedinordertobetterunderstandtheflood,getwithitanduseitthustoreduceflooddisaster.
简介:Chinaisoneofthecountrieswiththemostseriousfloodingdisasters.InChina,above70%ofbigcities,50%ofpopulationand75%ofindustrialandagriculturaloutputvaluearedistributedineasterncoastalareaswithseriousflooding.Therefore,enhancementoftheoreticalstudyandexperiencesummarizationofurbanfloodcontrolisofgreattheoreticalandpracticalsignificance.Aseconomyisdevelopingrapidly,urbanscaleisexpandingfast,andurbanfloodcontrolstandispromoted.Urbanfloodcontrolcallsfornewconceptandmethods.Thispapermakesasystematicsummarizationofconceptevolutionandadvancedmethodsconcerningurbanfloodcontrolathomeandabroad.Theconceptofurbanfloodcontrolhastransformedfromsimplefloodcontrolanddrainagetocoexistencewithanduseofflood.Floodcontrolmeasureshavetransferredformemphasisuponengineeringonestoprioritytobothengineeringandnon-engineeringones,withspecialattentiontoecologicalfloodcontrol,suchasmakingfulluseofecologicalrevetment,ecologicalrealignmentofariver,multi-objectivemanagementofurbanflooddetentionregion,turningfloodintoresourcesandutilizationofwetlands.
简介:Xiangxi河盆,在华中在西方的湖北省定位了,是有水资源的不同类、复杂的分布的一个石灰岩地区常见的地形山脉马槽区域。这篇论文在这石灰岩地区常见的地形盆比较表面和表面下的洪水的特征,利用一个一个参数Darcian模型和传统的指数的模型。观察自记水位计和推断的水部件为表面和表面下的洪水是惊人地类似的。Darcian模型和指数的模型基于洪水产生过程的不同看法,与适合有适合有多重时间常数的仅仅衰退手足的一个单个时间常数,和后者的全部自记水位计的前者。由于石灰岩地区常见的地形媒介的anisotropy和异质,包括3S的使用的物理、化学的技术的联合(遥感,地理信息系统,全球放系统)方法被建议让提高的水文学调查在多山的区域估计并且描绘石灰岩地区常见的地形水资源。
简介:统计方法通常被用来评估自然人口和环境变量,然而,这些必须在在一个演变世界上适当的人口特性认出时间的趋势。这里介绍的新方程定义历史的人口在人口工具和标准差由线性变化影响了的总数的统计措施。这些能被用来提取今日的人口的统计特性,需要定义现代可变性和风险,从历史的数据的表格,那被当条件是不同的时,做的大小统治。作为一个例子,象变化和在里面隧道结构正在引起的气候那样的许多因素充满层次升起,因此未来洪水层次的现实主义的评价必须考虑如此的世俗的变化。新方程在比习惯性地假定人口stationarity的正式计算高是0.5~2m的USA中西部为100年的洪水提供水层次的估计。这些方程也证明洪水层次将继续每年由几厘米升起。这率比海水平的上升快将近十倍,并且因此代表被柔韧的数据记录的变化的最快、很损坏的率之一。
简介:ThecoastallowlandsinnorthernJiangsuProvince,China,ischaracterizedbylowreliefandlowwatersurfacegradientinstreams.Thefloodingstagesarecommonlylowerthanthehigh-tidelevelandthetidalrangeisrelativelysmall.Allthesefactorsprohibitrapiddischargeoffloodwaterandmakethefloodregimeshereextremelysensitivetothesealevelrise.The1991PlumRainwasexamined,whenprecipitationwassignificantlyhigherthannormal.Theone-dimensionalopen-channelnon-conservativeflowmodelwasusedtosimulatethestreamflowinthechannelnetworkofstudiedarea.GIStechnologywasusedtodelineatethemaximuminundatedareabyanalyzingtheDEMs.
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简介:NanxiaohongandNangangmainsouthchannelarechosenasthetypicalfloodandebbchannels.HydrodynamicsanalysisbasedonfieldhydrologicalandsedimentdataisconductedwithGao-Collinsmodeltoanalysesedimenttransporttrends.Also,thegrainsizedistributionanalysisofthebottomsedimentsampledinSep.2001isusedasthebaseoftheanalysis.TheresultshowsthatthesedimentinNanxiaohongisfromtherivemoutharea.Thesedimenttransportsupwardswiththefloodflowwhichisstrongerthantheebbflow,i.e.,inthedirectionofSE-WN.Thesedimentinmainsouthchannelcomesfromupward.Theytransportdownwardswiththeebbflow,whichisstrongerthanthefloodflow,i.e.,inthedirectionofWN-SE.Thedirections,sourcesandmechanismofsedimenttransportareidentifiedaccordingtocomprehensiveanalysesoftheobserveddataonhydrodynamicsandsediment.
简介:索尔顿湖是在东南的加利福尼亚位于地形的关上的Salton马槽的最深的点的一个终端湖。它当前是在处于状态的区域的最大的湖。它被一个泛滥的事件在19051907沿着克罗拉多河创造,类似于在过去的世纪的历史的洪水在一样的地点创造了古老的卡休拉湖的短暂化身的方法。它在今天的中心的位置帝国山谷,一个热、干旱的地点家到一些在美国的最高效的灌溉农业陆地,通过在农业流量,它输入的主要形式,和广阔蒸发损失之间的精细的平衡保证了它的进行中的幸存。不过,它是的平行角色一个娱乐资源和重要野生动物产地,在它存在的第一个世纪建立了,被增加咸度减少威胁水质量,和从喂山谷农业的克罗拉多河的减少的水分配。将被影响由的逐渐地不明确的未来减少了的索尔顿湖脸从克罗拉多河,对到在山谷的支持耕作和能量工业的另外的水来源的要求,和稳定湖咸度的需要浇进口,维持娱乐资源,并且保存什么成为了重要生态系统和野生动物产地。
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简介:Serialgradesofcementmortarspecimenshavebeentestedonthemodelofcon-crete-liningflooddischargetunnelwithorifice,Theresultsshowthatincipientcavitationerosionnumberismuchsmallerthanincipientcavitationnumber.Basedontheprincipleofbubbledy-namics,theflowspeedeffectonincipientcavitationerosionnumberforcementmortarispre-sented.