给水排水专业英语课件(李田)2.ppt

Unit2,TheWorldFreshWaterResource,Newwordsandexpressions,environmentaladj.环境的，周围的integraladj.整体的，构成整体所需要的n.积分ecologicaladj.生态的，社会生态学的harborvt隐匿，庇护n.港湾,Newwordsandexpressions,aquaticadj.水的，水生的，水栖息的ecosystemn.生态系统speciesn.种类，物种；样式aqueductn.沟渠，导水管desalinate=desalinizev.除盐，海水淡化aridadj.干旱的，贫瘠的icebergn.冰山reverseadj.相反的，颠倒的n.vt.相反，颠倒,Newwordsandexpressions,aquifern.含水层，蓄水层rudimentaryadj.根本的,未发展的malarian.疟疾,瘴气typhoidn.adj.伤寒症，伤寒的choleran.霍乱wetlandn.湿地，沼泽地habitatn.(动植物的)生活环境,产地、栖息地,elucidateilu:sideitvt.阐明,说明Pleaseelucidatethereasonsforyouractiondwellingn.住处，房屋，公寓，住宅,sanitationn.卫生,卫生设施momentumn.动力,要素；动量；总冲量renewableadj.可更新的,可恢复的rechargev.n.再充电,再补充rechargeablerunoffn.溢流:Theoverflowoffluidfromacontainer.径流:Rainfallnotabsorbedbysoil.apportionv.分摊，分配：toapportionthemoneyfairlygaugen.标准尺,规格,量规,量表raingaugen.雨量计AmazonRiver亚马逊河Hawaiiha:waii:n.夏威夷，夏威夷岛,monsoonn.季候风,(印度等地的)雨季,季风Oceanian.大洋洲assessvt.估定,评定staticadj.静态的,静力的staticelectricitydynamicadj.动力的,动力学的,动态的,Freshwaterisafundamentalresource,integraltoallenvironmentalandsocietalprocess.Waterisacriticalcomponentofecologicalcycles.Aquaticecosystemsharbordiversespeciesandoffermanyvaluableservices.Humanbeingsrequirewatertorunindustry,toprovideenergy,andtogrowfood.,Freshwatersaltwater,Inordertomobilizewaterforhumanneeds,webuildhugereservoirstostorewaterfordryperiodsandholdbackfloodwaters,webuildaqueductstotransportwaterthousandsofkilometersfromwater-richtowater-poorregions;weburnoiltogenerateelectricityofdesalinatesaltwaterinaridregions;andwedreamoftowingicebergfromthepolarregionsandofreversingtheflowofmassiverivers.,Harshrealitiesintrudeonthesedreams.Asweapproachthe21stcenturywemustnowacknowledgethatmanyofoureffortofharnesswaterhavebeeninadequateormisdirected.Weremainignorantofthefunctioningofbasichydrologicprocess.Rivers,lakes,andgroundwateraquifersareincreasinglycontaminatewithbiologicalandchemicalwastes.Vastnumbersofpeoplelackcleandrinkingwaterandrudimentarysanitationservices.,Millionsofpeopledieeveryyearfromwater-relateddiseasessuchasmalaria,typhoid,andcholera.Massivewaterdevelopmentshavedestroyedmanyoftheworldsmostproductivewetlandsandotheraquatichabitats.Theeconomicandhydrologicresourcesformajornewirrigationprojectcannotbefound.Andexpectedchangesinglobalclimaticconditionwillalterfuturewatersupply,demand,andquality.,HinduandBuddhisttraditionsplacemythicalMountMeruthedwellingplaceofthegodsatthecentreoftheuniverse.Hereoriginatetheriveroftheearth,includingtheIndus,theGangesndi:z,andtheBrahmaputrabr:mpu:tr.,MountMeru,InearlyChristiantradition,thewatersoftheearthoriginateinthefountainsoftheGardenofEden,whichdividedintotheworldsgreatstream:theNile,theTigris,theEuphrates,theIndus,andtheGanges.Thesemythsariseinpartfromthesacredroleofwaterinsustaininglife,andinpartfromourearlyignoranceofthefunctioningofglobalwatercycle.,Bytheendofthe20thcentury,ourunderstandingofthestocks,flows,andconditionofglobalwaterresourcesisstilldistressinglyimperfect.TheInternationalHydrologicalDecade,coordinatedbytheUniteNationsofEducational,Scientific,andculturalorganization(UNSCO),beginninginthemid1960swassuccessfulinelucidatingmanyunknownaspectsoftheglobalhydrologicalcycleandsomeofthebestreferencesonglobalwaterresourcesstilldatefromtheperiod.,Unfortunately,withtheexceptionoftheUnitedNationsInternationalDrinkingWaterSupplyandSanitationDecadefrom1981to1990,therehasbeenlittlefollow-upunderstandingandsolvingcriticalwaterissues,andmuchofthemomentumofthatearlierperiodhaslost.,SamuelTaylorColeridge(1772-1834),inhisclassicpoem“TheRimeoftheAncientMariner”,effectivelydescribedtheprincipalcharacteristicoftheearthswaterresourceswhenhewrote,“water,water,everywhere,noranydroptodrink”.97%ofallthewateronearthissaltwaterunsuitablefordrinkingorgrowingcrops.Theremaining3%isfreshwater,comprisingatotalvolumeofabout35millionkm3.,Ifthiswaterwerespreadoutevenlyoverthesurfaceoftheearthitwouldmakealayerof70mthick.YetalmostallofthisfreshwateriseffectivelylockedawayintheicecapofAntarcticandGreenlandandindeepundergroundaquifers,whichremainstechnologicallyoreconomicallybeyondourreach.Lessthan100000km3just0.3%oftotalfreshwaterreservesonearthisfoundintheriversandlakesthatconstitutethebulkofourusablesupply.,Freshwaterisarenewableresourcemadecontinuouslyavailablebytheconstantflowtotheearthofsolarenergy,whichevaporateswaterfromtheoceansandlandandredistributesitaroundtheglobal.Morewaterevaporatedfromtheoceansthanfallonthemasprecipitation;thusthereisacontinuoustransferoffreshwaterfromtheoceanstothecontinent.,Thiswaterrunsoffintheriversandstreamsthatsustainournaturalecosystemsandsocietiesandrechargeouraquifers.Onanannualbasis,about45000km3peryeararereturnedtotheoceansasriversandgroundwaterrunoff.Ifthatrunoffwereevenlydistributed,eachpersononearthwouldreceivemorethan8000m3peryear.,Infact,thesefreshwaterresourcesarenotevenlydistributed.Rainfallandrunoffareapportionedinbothspaceandtimeinagrosslyirregularmanner.Weoftendontgetwaterwhenweneeditorwhereweneedit.Someplacesreceivedenormousquantities;othersreceivedalmostnone.,TheAtacamaDesertinSouthAmericaisoneoftheworldsdriestareas.TheraingaugeatArica,Chileroutinelyrecordszeroannualprecipitation.PicturesfromspacerevealcloudlessskiesoverthegreatSaharadesertofAfrica.Attheotherextreme,MountWaialealeweeleele,ontheislandofKauai,Hawaiihasrecordedmorethan11.5mofrainfallinasingleyear.,AtacamaDesert,Arica,Chile,Saharadesert,Otherexamplesoftheseseveredistributionproblemsabound.20%ofglobalaveragerunoffcomesfromtheAmazonRiveralone.AllofEuropeaccountsfor7%ofglobalrunoff;allofAustraliaproducesonly1%.30%ofthetotalrunoffinAfricacomesfromasingleriverbasin,theCongo/Zaire.,Manyregionsgetnearly100%oftheirprecipitationduringabrief,intenserainyseason.InCherrapunji,India,over10.5mofrainperyearmayfallduringthebriefperiodofthemonsoon.MuchofCaliforniagetsnorainfallatallfromMaytoSeptember,whichisapreciselytheperiodofgreatestwaterdemand.Fig.12showstheannualpercapitaavailabilityoffreshwaterbycontinent