可編輯可修改可編輯可修改歡迎下載，希望能幫到您歡迎下載，希望能幫到您水利水電工程專業(yè)英語(yǔ)——水文與水資源篇HydrologicalCycleandHydrologyisanearthscience.Itencompassestheoccurrence,distribution,movement,andpropertiesofthewatersoftheearthandtheirenvironmentalrelations.Closelyalliedfieldsgeology,climatology,meteorologyandoceanography.水文學(xué)是一門地球科學(xué)。它包含地球水資源的發(fā)生、分布、運(yùn)動(dòng)和特質(zhì)，以及其環(huán)境關(guān)系。與之密切相關(guān)領(lǐng)域包括地質(zhì)學(xué)，氣候?qū)W，氣象學(xué)和海洋學(xué)。Thehydrologiccycleisacontinuousprocessbywhichwateristransportedfromtheoceanstheatmospheretothelandandbacktothesea.Manysub-cyclesexist.Theevaporationofinlandwateranditssubsequentprecipitationoverlandbeforereturningtotheoceanisoneexample.Tdrivinforcfortheglobawatertranspoystemisprovidebythesun,whichfurnishetheenergyrequiredforevaporation.Notethatthewaterqualityalsochangesduringpassagethroughcycle;forexample,seawaterisconvertedtofreshwaterthroughevaporation.水文循環(huán)是一個(gè)連續(xù)的過(guò)程，在這個(gè)過(guò)程中水從海洋被運(yùn)輸?shù)酱髿庵?，降落到陸地，需要注意的是，水質(zhì)在水循環(huán)通道中也會(huì)改變，比如，海水在蒸發(fā)后就會(huì)轉(zhuǎn)變成淡水。Thecompletewatercycleisglobalinwaterproblemsregional,national,international,continental,andglobalscales.Practicalsignificanceofthethetotalsupplyoffreshwateravailabletotheearthislimitedandverysmallcomparedwithtwatercontentoftheoceanshasreceivedlittleattention.Thuswatersflowinginonecountrycabeavailablatthesametimeforuseinotheregionoftheworld.Modernhydrologisreobligatetocopewithproblemsrequirindefinitinvaryinscaleofsignificarderofmagnitudedifference.Inaddition,developingtechniquestocontrolweathermustreceivecarefulinoneareacanhydrologyandthereforethewaterresourcesofotherregions.完整的水循環(huán)在自然界中是全球性的。世界水問(wèn)題需要在區(qū)域，國(guó)家，國(guó)際，洲際和發(fā)展控制天氣的技術(shù)必須得到密切關(guān)注Becausethetotalquantityofwateravailabletotheearthisfiniteandindestructible,thhydrologicsystemmaybelookeduponasclosed.Openhydrologicsystemmaybelookeduponasclosed.Openhydrologicsubsystemsareabundant,however,andtheseareusuallythetypeanalyzeForanysystem,awaterbudgetcanbedevelopedtoaccountforthehydrologiccomponents.因?yàn)榈厍蛏峡衫玫乃渴怯邢耷也豢杀苊獾?，所以全球的水文循環(huán)系統(tǒng)可以被看成這些系統(tǒng)也是經(jīng)常被分析到的。對(duì)于任何系統(tǒng)，水預(yù)算都能夠轉(zhuǎn)變到對(duì)水文組成的計(jì)算。Figures1and2showahydrologicbudgetforthecoterminousUnitedStates.Thesefiguresillustratethecomponentsofthewatercyclewithwhichahydrologistisconcerned.Inapracticsense,somehydrologicregionisdealtwithandabudgetforthatregionisestablished.Suchremaybetopographicallydefined(watershedsandriverbasinsareexamples),politicallyspecifiedcountryorcitylimits),orchosenonsomeothergrounds.WatershedsordrainagebasinsaretheeasiestodealwithsinctheysharpldefinsurfacwaterboundariesThesetopographicallydeterminedareasaredrainedbyariver/streamorsystemofconnectingrivers/streamssuchoutflowisdischargethroughasingloutlenfortunatelisoftenecessartodealwithregionsthatarenotwellsuitedfortrackinghydrologiccomponents.Fortheseareas,thehydrolwillfindhydrologicbudgetingsomewhatofachallenge.12（如流域和河流盆地（如根據(jù)國(guó)家或者城市限制者溪流排水，因此所有的出流都從某個(gè)單一的出口排出。不幸Theprimaryinputinahydrologicbudgetisprecipitation.Someoftheprecipitation(e.g.rsnow,hailmaybeinterceptytreesgrassothevegetationdstructurbjectandwilleventuallyreturntotheatmospherebyevaporation.Onceprecipitationreachestheground,someitmayfilldepressions(becomedepressionstorage),partmaypenetratetheground(infiltrate)replenishsoilmoistureandgroundwaterreservoirs,andsomemaybecomesurfacerunoff,thatis,flowovertheerurfacetoadefinedchannelsuchasastream.在水文預(yù)算中首要的輸入是降水。部分降水（如雨、雪、冰雹）會(huì)被樹木、草地、其，部分會(huì)入滲到地下（滲透）表徑流，即流過(guò)地表進(jìn)入到已有的通道中，比如溪流。WaterenterinthegroundmaytakeseverapathsSomemaybedirectvaporateifadequatetransferfromthesoiltothesurfaceismaintained.Thiscaneasilyoccurwhereahighgroundwatetabl(frewatersurfaceiswithithelimitofcapillaranspotothegroundsurface.Vegetationusingsoilmoistureorgroundwaterdirectlycanalsotransmitinfiltratedtheatmospherebyaprocessknownastranspiration.Infiltratedwatermaylikewisereplenishsoimoisturedeficienciesandenterstorageprovidedingroundwaterreservoirs,whichinturnmaintadryweatherstreamflow.Importantbodiesofgroundwaterareusuallyflowingsothatinfiltratedwaterreachinthesaturatezonemaybetransportorconsiderabldistancebeforeitisdischarged.Groundwatermovementissubject,ofcourse,tophysicalandgeologicalconstraints.水進(jìn)入地表后可能有幾個(gè)途徑（被利用。如果土壤水到地表的轉(zhuǎn)移能夠得到保證，一Waterstoredindepressionswilleventuallyevaporateorinfiltratethegroundsurface.Surrunoffultimatelyreachesminorchannels(gullies,rivulets,andthelike),flowstomajorstreafinallyreachesanocean.Alongthecourseofastream,evaporationandinfiltrationcanalsooc儲(chǔ)存在洼地的水會(huì)最終蒸發(fā)或入滲到地表。地表徑流最終到達(dá)小的通道（等，流向大的溪流，最后到達(dá)海洋。在水流動(dòng)的過(guò)程中，蒸發(fā)和滲流也同時(shí)發(fā)生著。UnitHydrographs單位線Waystopredictfloodpeakdischargesanddischargehydrographsfromrainfalleventshavebeenstudiedintensivelysincetheearly1930s.Oneapproachreceivingconsiderableuseiscalletheunithydrographmethod.ItderivesfromamethodofunitgraphsemployedbySherman,in1932TheunitgraphisdefinedasfollowsXhuginfallproducesa10cmdepthofrunoffoverhydrographshowingwhichbeconsideredaunitgraphforthatwatershed.自20世紀(jì)30年代早期就已經(jīng)深入研究了降雨事件中預(yù)測(cè)洪峰流量和流量過(guò)程線的方1932該單位曲線定義如下：如果在給定的X小時(shí)內(nèi)，給定的流域上產(chǎn)生了10cm深的徑流，則在該流域出口斷面形成的地面徑流過(guò)程線即為單位線。Itisincorrecttodescribeaunithydrographwithoutspecifyingtheduration,XofthestothatproduceditXourunithydrographisdefinedasadirectrunoffhydrographhavinga10cm.VolumeandresultingfromanX-hourstormhavingasteadyintensityof10/Xcm/hr.A2-hrunithydrographwouldbebya2-hrstormduringwhich10cmofuniformlygeneratedoverthebasin.A1-dayunithydrographwouldbeproducedbyastormhaving10cmofexcessrainuniformlyproducedduringa24-hrperiod.ThevalueXisoftenafractionofhr.如果不指明單位線的降雨歷時(shí)XX小時(shí)的單位線被定10X10/X小時(shí)的體210212410X1X-hourunitgraphtootherthan10cmisaccomplishedsimplybymultiplyingtherainfallexcessamountbytheunitgraphordinates,sincetherunoffordinatesforagivendurationareassumedtobedirectlyproportionaltorainfallex3-hrstormproducing20cmofnetrainwouldhaverunoffrates2timesthevaluesofthe3-hrunhydrograph.5cmin3hrwouldproduceflowshalfthemagnitudeofthe3-hrunithydrograph.Thisassumptionofproportionalflowsappliesonlytoequaldurationstorms.采用X小時(shí)的單位線來(lái)計(jì)算并非等于10厘米的徑流過(guò)程，可簡(jiǎn)單地用凈雨深乘以單位線的縱標(biāo)，因?yàn)閷?duì)一個(gè)給定時(shí)段，單位線假定徑流與凈雨直接成正比。一個(gè)產(chǎn)生20厘米凈332353位線一半的量。該成比例徑流假設(shè)僅適用于相同歷時(shí)的暴雨。IfthedurationofanotherstormisanintegermultipleofX,thestormistreatedasaserendtoendX-hourstorms.First,thehydrographsfromeachXincrementofrainaredeterminedfrtheX-hourunithydrograph.Theordinatesarethenaddedatcorrespondingtimestodeterminethetotalhydrograph.如果另一個(gè)暴雨的歷時(shí)是X的整數(shù)倍，那么該暴雨就被視作一系列首尾相連的X小時(shí)暴雨系列。首先，每個(gè)X降雨增量的過(guò)程線由X小時(shí)單位線確定。然后在相應(yīng)的時(shí)間疊加到縱軸，以確定總的過(guò)程線。Implicitinderivingtheunithydrographistheassumptionthatrainfallisdistributedinsametemporalandspatialpatternforallstorms.Thisisgenerallynottrue;consequently,variinordinatesfordifferentstormofequaldurationcanbeexpected.在推導(dǎo)單位線隱含的假設(shè)是所有暴雨中降雨都按照相同的時(shí)間和空間類型而分布。這通常并不是真實(shí)的；因此，可以預(yù)期對(duì)于相同歷時(shí)的不同暴雨中的縱坐標(biāo)的變化。TheconstructionofunithydrographsforotherthanintegermultiplesofthederivedduratifacilitatedbyamethodknownastheS-hydrograph.TheprocedureemploysaunithydrographtoformanS-hydrographresultingfromacontinuousappliedrainfall.TheunithydrographtheorycabeappliedungaugedwatershedsbyrelatingunithydrographfeaturestowatershedcharacteristicsAsaresultoftheattemptedsynthesisofdata,theseapproachesarereferredtoassyntheticunhydrographmethods.Theneedtoalterdurationofaunithydrographencouragedstudiestodefinetheshortespossiblstormdurationthatisaninstantaneonitrainfalheconceptofinstantaneousunithydrograph(IUH)canbeusedinconstructionunithydrographsforotherderivedduration.S入了一個(gè)單位線以組成一個(gè)自所引用連續(xù)降雨產(chǎn)生的S（IUH）的概念可以被用于構(gòu)建非引用歷時(shí)的單位線。Methodsofderivingunithydrographsvaryandaresubjecttoengineeringjudgment.TheleveofsophisticationemployedtounraveltheproblemdependslargelyonthekindofissueinquestiSeveramethodsusefuinthedeterminatifunithydrographwilbediscussedTheyaresubdividedintostartingwithunithydrographsobtainedfromfielddataandmanipulatingthembyS-hydrographmethodsandconstructingsyntheticunithydrographs.獲得單位線的方法各異且受工程師判斷的影響。用來(lái)解開問(wèn)題的復(fù)雜程度在很大程度始從現(xiàn)場(chǎng)數(shù)據(jù)獲得單位線，然后用SDatacollectireparatooderivinaunihydrograpforagaugedwatershecanbeextremelytimeconsuming.Todevelopaunithydrograph,itisdesirabletoacquireasmanyrainfrecordsaspossiblewithinthetheamountanddistributionofrainfalloverthewatershedisaccuratelknown.PreliminarselectioofstormstouseinderivinahydrographforawatershedshouldberestrictedtohefollowingStormsoccurringindividually,thatis,simplestormstructure.Stormshavinguniformdistributionofrainfallthroughouttheperiodofrainfallexcess.Stormshavinguniformspatialdistributionovertheentirewatershed.布。要用于流域獲得單位線的降雨初步選擇應(yīng)該嚴(yán)格遵循如下：暴雨獨(dú)立地發(fā)生，即，單獨(dú)的暴雨結(jié)構(gòu)。在整個(gè)過(guò)量降雨期間，暴雨具有均勻的降雨分布。降雨在整個(gè)流域內(nèi)具有均勻的空間分布。TheserestrictionsplacebothupperandlowerlimitsonsizeofthewatershedtobeemployeAnupperwatershedsizeof2stormsoversuchareasarenotunrealisticandsomestudiesofaresvtu0tmunithydrographtechnique.Thelowerlimitofwatershedextentdependsonnumerousotherfactorsandcannotbepreciselydefined.Ageneralruleofthumbistoassu.uty,otherhydrologictechniqueshelpresolveunithydrographsforwatershedsoutsidethis2000是過(guò)于謹(jǐn)慎的，盡管在這些區(qū)域的通常暴雨并非不切實(shí)際并且一些面積達(dá)到3000平方公里地區(qū)的研究也應(yīng)用了單位線技術(shù)。流域范圍的下限取決于眾多的其他因素，并不能被準(zhǔn)確定義。一般的經(jīng)驗(yàn)是假設(shè)約10平方公里。幸運(yùn)的是，其它過(guò)程線技術(shù)可以幫助解決在這個(gè)范圍外的流域單位線。Thepreliminaryscreeningofsuitablestormsforunithydrographformationmustmeetmorerestrictivecriteriabeforefurtheranalysis:Durationofrainfalleventshouldbeapproximately10%-30%ofthedrainagearealagtimeDirectrunofffortheselectedstormshouldbegreaterthan5cm.Asuitablenumberofstormsshouldbeanalyzedtoobtainanaverageoftheordinatesforselectedunithydrographduration.ModificationsmaybemadetoadjustunithydrographdurationsbymeansofS-hydrographsofIUHprocedures.Directrunoffordinatesforeachstormshouldbereducedsothateacheventrepresents1cmofdirectrunoff.Thefinalunithydrographofaspecificdurationforthewatershedisobtainedbyaveragordinatesofselectedeventsandadjustingtheresulttoobtain10cmofdirectrunoff.1）降雨事件的歷時(shí)應(yīng)該大約是流域面積延遲時(shí)間的10%-30%。所選擇的暴雨的直接徑流應(yīng)該大于5IUH過(guò)程的S每場(chǎng)暴雨的直接徑流縱標(biāo)應(yīng)該被減少，所以每場(chǎng)降雨代表10流域特定歷時(shí)的最終單位線是通過(guò)平均所選擇降雨事件的縱標(biāo)和調(diào)整結(jié)果以獲得厘米的直接徑流而得到的。Constructiontheunithydrographinthiswayproducestheintegratedeffectofrunoffresulfromarepresentativesetofequaldurationstorms.Extremerainfallintensityisnotreflecteddetermination.Ifintensestormsareneeded,astudyofrecordsshouldbemadetoascertaintheiinfluenceuponthedischargehydrographandactualhydrographsfromintensestorms.用這種方式構(gòu)建單位線產(chǎn)生了徑流的綜合效應(yīng)，這來(lái)自一個(gè)代表系列的相同歷時(shí)的暴量過(guò)程線的影響以及強(qiáng)暴雨的實(shí)際過(guò)程線。Essentialstepsindevelopingaunithydrographforanisolatedstormfollow:Analyzethestreamflowhydrographtopermitsurfacerunofffromgroundwaterflow.Measurethetotalvolumeofsurfacerunoff(directrunoff)fromthestormproducingtheoriginalhydrographequaltotheareaunderthehydrographaftergroundwaterbaseflowhasremoved.Dividetheordinatesofdirectrunoffhydrographbytotaldirectrunoffvolumeininchesplottheseresultsversustimeasunitgraphforthebasin.Finally,theeffectivedurationoftherunoff-producingrainforthisunitgraphmustfromthehyetograph(timehistoryofrainfallintensity)ofthestormused.建立一個(gè)獨(dú)立暴雨單位線的基本過(guò)程如下：1）在移除地下水基流后，測(cè)量暴雨產(chǎn)生的地表徑流（直接徑流）了與過(guò)程線下該地區(qū)相等的原始過(guò)程線。成一個(gè)流域的單位線。4）Proceduresotherthanthoselistedarerequiredforcomplexstormsorindevelopingsynthetunitgraphswhenfewdataareavailable.Unithydrographscanalsobetransposedfromonebasinanotherundercertaincircumstances.更復(fù)雜的暴雨或者當(dāng)有很少可用資料情況下建立綜合單位線時(shí)會(huì)需要除上述列出以外的步驟。在某些情況下，也可以將一個(gè)流域的單位線移用到另外一個(gè)流域。FloodFloodforecasting,reservoirdesign,watershedsimulation,andcomprehensivewaterresourceplanninggenerallyutilizesomeformofroutingtechnique.Routingisusedtopredictthetemporandspatialvariationsofafloodwaveasittraversesariverreachorreservoir,oritcanbetopredicttheoutflowhydrographfromawatershedsubjectedtoaknownamountofprecipitation.Routingtechniquesmaybeclassifiedintotwocategories-hydrologicroutingandhydraulicroutin洪水預(yù)測(cè)、水庫(kù)設(shè)計(jì)、流域仿真和水資源綜合規(guī)劃通常應(yīng)用某種形式的演算技術(shù)。演算被用來(lái)預(yù)測(cè)一個(gè)洪峰在通過(guò)一個(gè)河段或水庫(kù)時(shí)的時(shí)間和空間變化Hydrologicroutingemploystheequationofcontinuitywitheitherananalyticoranassumedrelationbetweenstorageanddischargewithinthesystem.Hydraulicrouting,ontheotherhand,boththeequationofcontinuityandtheequationofmotion,customarilythemomentumequation.Thisparticularformutilizesthepartialdifferentialequationsforunsteadyflowinopenchannmoreadequatelydescribesthedynamicsofflowthandoesthehydrologicroutingtechnique.水文演算應(yīng)用了連續(xù)性方程，表達(dá)系統(tǒng)內(nèi)儲(chǔ)蓄和排放之間的一個(gè)分析或假設(shè)的關(guān)系。形式使用偏微分方程來(lái)表達(dá)明渠的非恒定流。它比水文演算技術(shù)更充分地描述水流動(dòng)力情況。Applicationsofhydrologicroutingtechniquestoproblemsoffloodprediction,evaluationsfloodcontromeasuresandassessmenttheeffectofurbanizatirenumerous.Mostfloodwarningsystemsincorporatethistechniquetopredictfloodstagesinadvanceofaseverestorm.themethodmostfrequentlusedtosizespillwayforsmallintermediatndlargdams.Additionally,thesynthesisofrunoffhydrographsfromgaugedandungaugedwatershedsispossiblbytheuseofthisapproach.水文演算技術(shù)在洪水預(yù)測(cè)問(wèn)題、防洪措施評(píng)估以及城鎮(zhèn)化影響評(píng)價(jià)中有很多應(yīng)用。大程的綜合可能使用這種方法。Hydrologicriverroutingtechniquesareallfoundedupontheequationofcontinuity(1)whereIistheinflowratetohee,outflowratefromthSehterateofchangeofstoragewithinthereach.(1)（1）水文河流演算技術(shù)都建立在連續(xù)性方程的基礎(chǔ)上（1）其中I是到達(dá)該河段的入流速率，O是河段的出流速率，dS/dt是河段內(nèi)蓄水的變化速率。(2)Storageinastableriverreachcanbeexpectedtodependprimarilyonthedischargeintoaoutofareachandonhydrauliccharacteristicsofthechannelsection.Thestoragewithintheagiventimecanbeexpressedas(2)Constantsaandnreflectthestagedischargecharacteristicsofcontrolsectionsateachendoftreach,adanmmirrorthestage-volumecharacteristicsofthesectindnarrelativeweightsgiventoinflowandoutflowforthereach.（2）穩(wěn)定河段中的蓄水量主要取決于該河段的入流和出流，以及河流斷面的水力特征值。在給定時(shí)間點(diǎn)的河段內(nèi)蓄水量可以被表示為（2）常數(shù)a和nb和mX(3)TheMuskingummethodassumestan=1andla=K,resultingin(3)whereKisthestoragetimeconstantforfactorthatvariesbetween0and0.5.（3）馬斯京根法假設(shè)m/n=1且令b/a=K，得到（3）其中K是河段存儲(chǔ)時(shí)間常數(shù)，X是在0-0.5之間的權(quán)重因數(shù)。ApplicationofthisequationhasshwnhsuallyreasonablyclosetothewavetraveltimethroughthereacXaveragesabout0.2.該方程的應(yīng)用已經(jīng)表明K通常合理地接近于水流通過(guò)河段流動(dòng)的時(shí)間，且X平均值約0.2。Behaviorofthefloodwaveduetochangesinthevalueofisreadilyapparent.Theresultingdownstreamfloodwaveiscommonlydescribedbytheamountoftranslationthatis,thetimelagandbytheamountofattenuationorreductioninpeakdischarge.ThevaluX=0.5resultsinapuretranslationofthefloodwave.權(quán)重因數(shù)XX=0.5時(shí)導(dǎo)致了洪峰的單純的平移。ApplicationofEqs.(1)and(3)toariverreachisastraightfowprreureifknown.Theroutingprocedurebeginsbydividingtimeintoanumberofequalincrements,Δt,andexpressingEq.(1)infinitedifferenceform,usingsubscripts1and2todenotet-=(4)beginningandendingtimsoThis-=(4)-=（4）如果K和X已知，那么方程和在河段中的應(yīng)用就是非常簡(jiǎn)單的流程。演算12-=（4）TheroutingtimeinevsnormallyassignedanyconvenientvaluebetweenthelimitsofK/3andK.演算時(shí)間間隔Δt通常被指定為K/3和K的界限之間的任何方便的值。(5)ThestoragechangeintheriverreachduringtheroutingintervalfromEq.(3)is(5)(6)andsubstitutingthisintoEq.(4)resultsintheMuskingumroutingequation(6)InwhichNotethtanΔtmusthavethesametimeunitsandalsothatthethreecoefficientssumto1.0.方程（3）中演算間隔中河段內(nèi)的蓄水變化為馬斯京根方程（5）（6）將此式帶入方程（4）中得到（5）（6）其中注意K和Δt必須有相同的單位且三個(gè)系數(shù)和為1.0。Theoreticalstabilityofthenumericalmethodisaccmls

etweenthelimits2KXand2(1X).Thetheoreticalvluiothetimerequiredforanelemental(kinematic)wavetotraversethereach.Itisapproximatelythetimeintervalbetweeninflowandoutflowpeaks,iavailable.Ifnot,thewavevelocitycanbeestimatedforvariouschannelshapesasafunctofaveragevelocityVforanyrepresentativeflowrateQ.VelocityforsteadyuniformflowcanbestimatedbyeithertheManningorChezyequation.如果2KX和2K）K的理論值（運(yùn)動(dòng)峰值之間的時(shí)間間隔。如果不是，波速可以對(duì)不同的渠道形狀作為代表性流量Q的平均速率的函數(shù)來(lái)估算。穩(wěn)定均勻流的速度可以通過(guò)曼寧或謝才公式來(lái)估算Since1an2areknownforeverytimeincrement,routingisaccomplishedbysolvingEq.successivetimeincrementsusinOeh1forthenexttimeincrement.和O2O1程（6）的連續(xù)的時(shí)間增量，從而完成演算。WaterQualityBecausewaterqualitisinextricabinkedtowaterquantittisimportanforhydrologistounderstandthesignificancofdevelopingmodelingtechniquesthatcanaccommodatebothfeatures.由于水質(zhì)與水量密不可分，因此了解開發(fā)能夠適用于兩個(gè)特性的建模技術(shù)對(duì)水文學(xué)家來(lái)說(shuō)是很重要的。Awaterqualitmodelisamathematicastatemenorseofstatementthaequatwaterqualityatapointofinteresttocausativefactors.Ingeneral,waterqualitymodelsaredesignacceptasinput,constituentconcentrationversustimeatpointsofentrytothesystem,(2)simthemixingandreactionkineticsofthesystem,and(3)synthesizeatime-distributedoutputatsystemoutlet.水質(zhì)模型被設(shè)計(jì)于1）作為輸入條件，在系統(tǒng)入口處濃度與時(shí)間的關(guān)系）模擬混合及系統(tǒng)的動(dòng)力學(xué)反應(yīng)，以及綜合為一個(gè)系統(tǒng)出口處隨時(shí)間分布的輸出。Eitherstochastic(containingprobabilisticelements)ordeterministicapproachesmaybetaindevelopingmethodsforpredictinpollutionoadsTheformertechniquisbasedondeterminingthelikelihood(frequency)ofaparticularoutputqualityresponsebystatisticalmeaThisissimilatofrequencanalysioffloodorlowflowsWaterqualitrecordshouldbeavailablforatleas5years(andpreferablmuchlongerifestimateofinfrequenteventsaretobereliable.隨機(jī)（包含概率元素）或確定性方法都可能被用于開發(fā)預(yù)測(cè)污染負(fù)荷的方法。前者技術(shù)基于通過(guò)統(tǒng)計(jì)方法確定的一個(gè)特定的輸出質(zhì)量響應(yīng)的可能性（頻率5（長(zhǎng)）的水質(zhì)記錄。Thedeterministicapproach(outputexplicitlydeterminedforagiveninput)requiresthatamodelbedevelopedtorelatewaterqualityloadingtoaknownorassumedhydrologicinput.modelcanrangefromanempiricaconcentratiischargrelatiotoaphysicaequationrepresentingthehydrochemicalcycle.Theultimatemodelingtechniqueisthatwhichbestdefinestheactualmechanismtriggeringthewaterqualityresponse.Thecauseofagivenstateofpollut確定性方法（對(duì)于給定的輸入明確地確定輸出）要求一個(gè)模型被開發(fā)于將水質(zhì)負(fù)荷與一個(gè)已知的或假設(shè)的水文輸入關(guān)聯(lián)起來(lái)隨后即可具體確定給定污染狀態(tài)的起因。Waterqualitymodelsvaryintheircomplexity.Theirnaturedependsontheapplicationtobmadeofthemodel,theavailabilityofdata,andthelevelofunderstandingofthehydrochemicalhydrobiologicalprocessesinvolved.Unfortunately,thecomplexitiesoftheseprocesses,whichargreat,makethedifficultiesassociatedwithhydrologicalmodelingseemsmallincomparison.水質(zhì)模型的復(fù)雜性各有不同。其本質(zhì)取決于作為模型的應(yīng)用、數(shù)據(jù)的可獲得性以及對(duì)擬相關(guān)聯(lián)的復(fù)雜性看起來(lái)相對(duì)較小。Ingeneralwaterqualitmodelsshouldpermiacceptancofinputintermsofpollutant(constituent)concentrationversustimeatpointsofentryintothesystem,descriptionoftheandreactionkineticsinthestreamelementorgroundwaterelementofconcern,andsynthesistime-distributpuindicatiollutaoncentratittheoutleoftheelement(segment)beingmodeled.Ananalogymaybedrawntothestreaflowroutingwhichisperformeinadownstreamsequencefromonestreamchannelsegmenttoanother.Inthecaseofwaterqualitymodeling,thecommonrepresentationisthecalculationofchangeinconstituentconcentrationaspassesthroughsuccessivestatesofthewaterbodybeingmodeled.通常來(lái)講，水質(zhì)模型應(yīng)該允許在系統(tǒng)進(jìn)口處的污染物（組分）濃度相對(duì)時(shí)間的輸入形Asinthecaseofotherwaterresourcesmodelingprocesses,theapproachmaybedeterministorstochastic.Inthecaseofwaterqualitymodels,thestochasticapproachisoftenruledactuarecordofwaterqualitparameterareunavailablforlongenoughperiodtopermittobebeusedforthispurposeifadequatemathematicalstatementsrepresentingthekineticsofthesystemcanbedevelopedandtheirparametersdetermined.對(duì)于其它水資源模擬過(guò)程，其方法可以是確定性或隨機(jī)性的。對(duì)于水質(zhì)模型，隨機(jī)方那么所產(chǎn)生的序列可以被用于此目的。Thedeterministicapproachtowaterqualitymodelingrequiresthatrelationsbetweenqualitloadinandthefloworhydraulifeatureofthesystembeestablishndthatheappropriahemicaand/obiologiceactioetractaborsolutionheretheory-basedrelationscannotbeemployed,empiricalrelationsareoftenused.Theoptimummodeltousewouldbetheonebestdefiningtheactualwaterqualityresponseofthesystem.Manymodelshavebeendeveloped.水質(zhì)模擬的確定性方法須要建立水質(zhì)負(fù)荷與系統(tǒng)水流或水動(dòng)力特性之間的關(guān)系，以及對(duì)于解決方案已預(yù)處理的合適的化學(xué)和或生物反應(yīng)。其中，不能使用基于理論的公式，但被建立起來(lái)。Pollutantmaybeclassifisconservativornonconservativ(constituenavingtime-dependentdecays);somewhatmorespecificallyasorganic,inorganic,radiological,thermal,biologicandfinalltheymaybecategorizebyspecififormssuchasBOD,phosphorus,nitrogen,bacteria,viruses,andspecifictoxicsubstances.Thesepollutantsmaybeloadedwatercourseorgroundwatersystemfromeitherpointornonpointsources.污染物可以分為保守型和非保守型（組分隨時(shí)間衰減放射性、溫度或生物；且最終它們可以被分為具體的形式，如BOD、磷、氮、細(xì)菌、病毒和具體的有毒物質(zhì)。這些污染物可能通過(guò)點(diǎn)源或非點(diǎn)源被加入水體或地下水系統(tǒng)中。Thetimerateofdeliveryofadeterminedifitscharacteristicsaretobemodifiebymanagementpracticritimpactonsomeelementofthesystemevaluateorexample,theconsequencesofsomequantityofsiltdeliveredtoalakewouldnotbethesameifwereintroducedoveraperiodof5daysasopposedto2hr.Thusmonitoringofwaterqualitymusgenerallybeonacontinuousbasisifthedataaretobeofvalueforwaterresourcesplanningdevelopingcontinuousmodelingprocesses.如果要通過(guò)管理實(shí)踐或者對(duì)所評(píng)估系統(tǒng)一些元素的影響來(lái)改動(dòng)污染物的特性，那么就52湖的某些數(shù)量的淤泥的結(jié)果就不相同。因此，如果數(shù)據(jù)對(duì)水資源規(guī)劃和或發(fā)展中的連續(xù)建模過(guò)程是有利用價(jià)值的，那么監(jiān)測(cè)水質(zhì)一般必須在連續(xù)的基礎(chǔ)上。asdemand,andlivinorganismsalhavetime-dependendecaysandarethusnonconservatinnatureFordealinwithsuchconstituenisnecessarthaboththemixingpropertindthereactionkineticofthesystembeapproximatedOntheotherhand,manyinorganipollutanreconservatinnaturandtheihandlindependsmainlyonanabiliomodelthemixingmechanicsofthereceivingbodyofwater.不穩(wěn)定的污染物如放射性物質(zhì)、熱、生化需氧量和活的生物體都隨時(shí)間衰減并因此具Theproblemassociatedwithmodelingchemicalandbiologicalchangesinawaterbodyaremanyandcomplex.ThefieldconditionsencounteredinnaturesystemarehighlyvariedandoftennegatethevalidityofreactionrateandothermechanismsdeterminedunderlaboratoryconditionsFurthermore,pollutantsderivedfromnonpointsourcesaresubjectedtomanyalterationsintheirtravelsoverand/orthroughthegroundbeforetheyreachawatercourse.Thehighlyvariedchemical,biological,andhydrauliccharacteristicsofthelandmustbewithinestimatinpollutaoadingfromthesesourcesAlthoughqualitatiescriptiofhydrochemicalandhydrobiologicalprocessesareeasytocomeby,theirquantificationissomethielsagainFortunatelnsomecasesempiricarelatioetweenpollutaoncentratindstreamfloworotherhydrologicvariablescanbeusedtodescribewaterqualityloadingmechanisthatcannotbeobtainedonamoretheoreticalbasis.Itshouldbestressed,however,thatamodeonlyasgoodasthedataandtheoryonwhichitisbased.與模擬水體中化學(xué)和生物變化相關(guān)的問(wèn)題有很多且復(fù)雜。在自然界系統(tǒng)遇到的現(xiàn)場(chǎng)條WaterResourcesInaccordancewiththeabovediscussionweshall,firstofall,trytoformulatetheobjectwatermaybedoneineachwithmeritsandshortcomings.Letusconsiderthefollowingdefinitionandsubsequentqualifications:Theobjectofwaterresourcesplanningistomakethemosteffectiveuseoftheavailablewaterresourcestmeetalltheforeseeableshort-termandlong-termneedsofthenatfeimplythatthewell-beingofallthepeopleshouldbemaximized,whileatthesametimethetotaphysicaleffortisminimized.Tstermandlongtplythatwaterresourcesmustbemanagedandconservednotonlyforforcome.Theinterpretationofthshouldgobeyondphysicalneedsofindustryandagriculture,intotherealmofspiritueeds.TousethewordsoftheU.S.PresidesWaterResourcesCouncil(1962)Properwaterresourcemanagementrequirethafulconsideratiegivent…theinspiration,enjoymentandeducationofhepeople根據(jù)上述的討論，我們首先應(yīng)該確定水資源規(guī)劃的目標(biāo)。這可以通過(guò)很多方式確定，效地利用可利用的水資源以滿足國(guó)家所有的可見(jiàn)的短期和長(zhǎng)期（用水）一詞是指水資源必須被管控，能夠?qū)崿F(xiàn)當(dāng)代和后續(xù)世世代代的維持利用。長(zhǎng)的話說(shuō)196：適當(dāng)?shù)乃Y源管理須要充分考慮到人們的……精神、享受和教育。Themostappropriaeographicauniforwaterresourceplanninisusualltheriverdrainagebasin.Inthisacanrealizetheadvantaguipleuse,reconcileinterestsofwateruse,andachievethebestco-ordinationbetweenallinterestsconcerned.Thesverywellextendintootherareasofasforestry,agricultudminingItisnotunlikelthaiisfoundthatheplanninstudieshouldbeextendedtogroupsofcloselyrelateddrainagebasins.對(duì)于水資源規(guī)劃最合適的地理單元通常是河流流域。通過(guò)這種方式我們能夠?qū)崿F(xiàn)水資Todiscussallelementsofwaterresourcesplanninginsuchamannerthatalogicalsequencthoughtismaintained,whileattheendafullunderstandingofthesubjectisacquired,isnotassignment.ManyelementsareinterrelatedandonewouldhavetomovebackandforthoverthesubjecmateriaseveratimestobringthemalintproperfocusThemannerandcontenofdiscussionthathasbeenselectedforthepresentpurposefollowssomewhatalongthelinesofthreporBasicConsiderationsinWaterResourcesaaredbytheCommitteeonWaterResourcesPlanning,ASCE,ofwhichtheauthorwasamemberwhenthereportwasbeingprepared.Asafirstaidtothefollowingdiscussionsletusbrieflyreviewwhatisinvolvedinwaterresoplanningbeforeweproceedtodetails.要通過(guò)維持思維邏輯順序且最后能夠完全理解對(duì)象的方式，來(lái)討論水資源規(guī)劃的所有為實(shí)現(xiàn)本宗旨的方式和內(nèi)容在某種程度上沿襲了美國(guó)土木工程協(xié)會(huì)水資源規(guī)劃委員會(huì)報(bào)告Basicdata(beforeanyplanscanbemade,factsandfiguresmustbecollected).streamflow(acollectionofalldatapertainingtorun-off,thissectionbecomesinefwaterresourcesinventoryofthebasin).geophysical(mapsofthebasinshowingstreams,topography,soils,geologicalformationforestcover,andminerals).economic(howmanypeopleliveinthebasinandwhatdotheproduce).jurisdictional(whatlevelsofgovernmentareinvolvedandhowdotheyoperate).1）基礎(chǔ)數(shù)據(jù)（在任何計(jì)劃實(shí)施前，事實(shí)和數(shù)據(jù)都必須收集。河流流量（收集所有有關(guān)徑流的資料，實(shí)際上這一部分將成為流域水資源清單）物探（流域出流，地貌，土壤，地質(zhì)構(gòu)造，森林覆蓋率和礦物質(zhì)圖）經(jīng)濟(jì)（居住在該流域的人口數(shù)，以及其從事產(chǎn)業(yè)）司法管轄區(qū)（涉及哪些各級(jí)政府以及它們?nèi)绾芜\(yùn)作。Economicbaseprojectianestimatofthefuturgrowthofthepopulatioandtheeconomyinthebasin).forthenearfuture.forthefarfuture.2）經(jīng)濟(jì)基礎(chǔ)投影（對(duì)流域內(nèi)未來(lái)人口和經(jīng)濟(jì)增長(zhǎng)的估計(jì)近期。遠(yuǎn)期。Waterrequirements(howmuchwaterisneededfordifferentpurposes,inaccordancetheeconomicbaseprojection).domesticandindustrialuse.irrigation.navigation.power.floodcontrol(thisisaproblemofcontrollingexcessflowsratherthanconsumptiveusrecreation.3）用水需求（不同用途所需水量，由經(jīng)濟(jì)基礎(chǔ)投影確定生活和工業(yè)用水。灌溉。航運(yùn)。發(fā)電。防洪（這是更多的是要解決控制過(guò)多流量問(wèn)題而不是消耗性利用。娛樂(lè)。Developmentofplan(thaboveisolattudiearenowintegrateeservoiranals,hydraulicstructuresarelaidoutsothatmaximumefficiencyisobtained).priorityofwateruse(ifthedemandforwaterexceedstheavailability,apriorit