高考英语考前突破阅读理解能力科普类人小型水电站有损生态系统素材

1小型水电站有损生态系统Researchersconcludeinanewreportthataglobalpushforsmallhydropower（水力发电）projects,supportedbyvariousnationsandalsotheKyotoProtocoltoreducegreenhousegasemissions,maycauseunanticipatedandpotentiallysignificantlossesofhabitatandbiodiversity.Anunderlyingassumptionthatsmallhydropowersystemsposefewerecologicalconcernsthanlargedamsisnotuniversallyvalid,scientistssaidinthereport.Afive-yearstudy,oneofthefirstofitstype,concludedthatforcertainenvironmentalimpactsthecumulativedamagecausedbysmalldamsisworsethantheirlargercounterparts.ThefindingswerereportedbyscientistsfromOregonStateUniversityinthejournalWaterResourcesResearch,inworksupportedbytheNationalScienceFoundation.TheconclusionswerebasedonstudiesoftheNuRiversysteminChinabutarerelevanttonationalenergypoliciesinmanynationsorregions--India,Turkey,LatinAmerica--thatseektoexpandhydroelectricpowergeneration.Hydropowerisgenerallyfavoredovercoalinmanydevelopingareasbecauseitusesarenewableresourceanddoesnotcontributetoglobalwarming.Also,thesocialandenvironmentalproblemscausedbylargedamprojectshaveresultedinarecenttrendtowardincreasedconstructionofsmalldams.TheKyotoProtocol,underCleanDevelopmentMechanism,isfundingtheconstructionofsomeofthesesmallhydroelectricprojects,withthegoalofcreatingrenewableenergythat'snotbasedonfossilfuels,saidDesireeTullos,anassociateprofessorintheOSUDepartmentofBiologicalandEcologicalEngineering.Theenergymayberenewable,butthisresearchraisesseriousquestionsaboutwhetherornottheoverallprocessissustainable,Tullossaid.Thereisdamagetostreams,fisheries,wildlife,threatenedspeciesandcommunities,shesaid.Furthermore,theprojectsareoftenlocatedinareaswherepovertyandilliteracyarehigh.Thebenefittotheselocalpeopleisnotalwaysclear,assomeofthesmallhydropowerstationsareconnectedtothenationalgrid,indicatingthattheelectricityisbeingsentoutsideofthelocalregion.Theresultcanbeprofoundandunrecognizedimpacts.Thisstudywasoneofthefirstofitstypetolookatthecompleterangeofimpactscausedbymultiple,smallhydroelectricprojects,bothinabiophysical,ecologicalandgeopoliticalbasis,andcomparethemtolargedamprojects.ItfocusedontheremoteNuRiverinChina'sYunnanProvince,wheremanysmalldamsproducing50megawattsofpowerorlessarebuiltontributariesthatfallrapidlyoutofsteep2mountains.Therearealready750,000damsinChinaandaboutonenewdamisbeingbuilteveryday,researcherssay.