2023年刘文勇黄金阅读真题奥加拉拉蓄水层的枯竭.docx

智课网TOEFL备考资料刘文勇黄金阅读真题：奥加拉拉蓄水层的枯竭摘要：最新版《刘文勇黄金阅读7.0版本》高清PDF格式支持免费下载，下面是小编整理的刘文勇黄金阅读真题：奥加拉拉蓄水层的枯竭(最新pdf版本)，希望对大家备考托福有所帮助DepletionoftheOgallalaAquifer奥加拉拉蓄水层的枯竭ThevastgrasslandsoftheHighPlainsinthecentralUnitedStatesweresettledbyfarmersandranchersinthe1880’s.Thisregionhasasemiaridclimate,andfor50yearsafteritssettlement,itsupportedalow-intensityagriculturaleconomyofcattleranchingandwheatfarming.Intheearlytwentiethcentury,however,itwasdiscoveredthatmuchoftheHighPlainswasunderlainbyahugeaquifer(arocklayercontaininglargequantitiesofgroundwater).ThisaquiferwasnamedtheOgallalaaquiferaftertheOgallalaSiouxIndians,whoonceinhabitedtheregion.TheOgallalaaquiferisasandstoneformationthatunderliessome583,000squarekilometersoflandextendingfromnorthwesternTexastosouthernSouthDakota.WaterfromrainsandmeltingsnowshasbeenaccumulatingintheOgallalaforthepast30,000years.EstimatesindicatethattheaquifercontainsenoughwatertofillLakeHuron,butunfortunately,underthesemiaridclimaticconditionsthatpresentlyexistintheregion,ratesofadditiontotheaquiferareminimal,amountingtoabouthalfacentimeterayear.ThefirstwellsweredrilledintotheOgallaladuringthedroughtyearsoftheearly1930’s.Theensuingrapidexpansionofirrigationagriculture,especiallyfromthe1950’sonward,transformedtheeconomyoftheregion.Morethan100,000wellsnowtaptheOgallala.Modernirrigationdevices,eachcapableofspraying4.5millionlitersofwateraday,haveproducedalandscapedominatedbygeometricpatternsofcirculargreenislandsofcrops.OgallalawaterhasenabledtheHighPlainsregiontosupplysignificantamountsofthecotton,sorghum,wheat,andcorngrownintheUnitedStates.Inaddition,40percentofAmericangrain-fedbeefcattlearefattenedhere.Thisunprecedenteddevelopmentofafinitegroundwaterresourcewithanalmostnegligiblenaturalrechargerate—thatis,virtuallynonaturalwatersourcetoreplenishthewatersupply—hascausedwatertablesintheregiontofalldrastically.Inthe1930’s,wellsencounteredplentifulwateratadepthofabout15meters;currently,theymustbedugtodepthsof45to60metersormore.Inplaces,thewatertableisdecliningatarateofameterayear,necessitatingtheperiodicdeepeningofwellsandtheuseofever-more-powerfulpumps.Itisestimatedthatatcurrentwithdrawalrates,muchoftheaquiferwillrundrywithin40years.ThesituationismostcriticalinTexas,wheretheclimateisdriest,thegreatestamountofwaterisbeingpumped,andtheaquifercontainstheleastwater.ItisprojectedthattheremainingOgallalawaterwill,bytheyear2030,supportonly35to40percentoftheirrigatedacreageinTexasthatissupportedin1980.ThereactionoffarmerstotheinevitabledepletionoftheOgallalavaries.Manyhavebeenattemptingtoconservewaterbyirrigatinglessfrequentlyorbyswitchingtocropsthatrequirelesswater.Other,however,haveadoptedthephilosophythatitisbesttousethewaterwhileitisstilleconomicallyprofitabletodosoandtoconcentrateonhigh-valuecropssuchascotton.Theincentiveofthefarmerswhowishtoconservewaterisreducedbytheirknowledgethatmanyoftheirneighborsareprofitingbyusinggreatamountsofwater,andintheprocessaredrawingdowntheentireregion’swatersupplies.Inthefaceoftheupcomingwatersupplycrisis,anumberofgrandioseschemeshavebeendevelopedtotransportvastquantitiesofwaterbycanalorpipelinefromtheMississippi,theMissouri,ortheArkansasrivers.Unfortunately,thecostofwaterobtainedthroughanyoftheseschemeswouldincreasepumpingcostsatleasttenfold,makingthecostofirrigatedagriculturalproductsfromtheregionuncompetitiveonthenationalandinternationalmarkets.Somewhatmorepromisinghavebeenrecentexperimentsforreleasingcapillarywater(waterinthesoil)abovethewatertablebyinjectingcompressedairintotheground.Evenifthisprocessprovessuccessful,however,itwouldalmosttriplewatercosts.Geneticengineeringalsomayprovideapartialsolution,asnewstrainsofdrought-resistantcropscontinuetobedeveloped.Whateverthefinalanswertothewatercrisismaybe,itisevidentthatwithintheHighPlains,irrigationwaterwillneveragainbetheabundant,inexpensiveresourceitwasduringtheagriculturalboomyearsofthemid-twentiethcentury.Paragraph1：ThevastgrasslandsoftheHighPlainsinthecentralUnitedStatesweresettledbyfarmersandranchersinthe1880’s.Thisregionhasasemiaridclimate,andfor50yearsafteritssettlement,itsupportedalow-intensityagriculturaleconomyofcattleranchingandwheatfarming.Intheearlytwentiethcentury,however,itwasdiscoveredthatmuchoftheHighPlainswasunderlainbyahugeaquifer(arocklayercontaininglargequantitiesofgroundwater).ThisaquiferwasnamedtheOgallalaaquiferaftertheOgallalaSiouxIndians,whoonceinhabitedtheregion.1.Accordingtoparagraph1,whichofthefollowingstatementsabouttheHighPlainsistrue?○Untilfarmersandrancherssettledthereinthe1880’s,theHighPlainshadneverbeeninhabited.○TheclimateoftheHighPlainsischaracterizedbyhigher-than-averagetemperatures.○ThelargeaquiferthatliesunderneaththeHighPlainswasdiscoveredbytheOgallalaSiouxIndians.○Beforetheearly1900’stherewasonlyasmallamountoffarmingandranchingintheHighPlains.Paragraph2：TheOgallalaaquiferisasandstoneformationthatunderliessome583,000squarekilometersoflandextendingfromnorthwesternTexastosouthernSouthDakota.Waterfromrainsan。