农业水资源

SymposiumonEnvironmentalChangesandEfficientUseofAgriculturalResources,(Oct.21~22,2011,Shijiazhuang,China)AgriculturalwatersavingstudiesforasustainablewatermanagementintheNorthChinaPlain(NCP)ChangmingLiuAgriculturalResourcesResearchCenter,CASKeyLab,IGSNRR,CAS,WaterScienceCollegeBNUOutlineMajorfeaturesofNCP’swaterresourcesMainWaterissues:rapidsocial-economicdevelopmentandclimatechangeAgriculturalwater-saving:thehighlightsDiscussionsofsomeideasofwater-savingAgriculturalwater-saving:Policy&CountermeasuresMajorfeaturesofNCP’swaterresourcesAnnualprecipitationinmmAverageannualprecipitationfrom1951to2008TheNCP:inthesemi-arid&semi-humidregion.Annualprecipitationaround350and800mmThemonsoonseason(JunetoSeptember)contributesmorethan80%ofannualrainfallMajorfeaturesofNCP’swaterresourcesPotentialevapotrnspirationinmmAnnualPotentialevapotrnspirationintheNCPishighvariesbetween796and1257mmresultinginmuchwaterlossAverageannualPotentialevapotrnspirationfrom1951to2008MajorfeaturesofNCP’swaterresourcesAridityindexThearidityindexvariesfrom1.0to3.2..It’sintheclimatetransitionzone.MajorfeaturesofChina’swaterresourcesAnnualevapotraspiratiominmmAverageannualevapotrnspirationfrom1951to2008calculatedbytheBudykohypothesis.MajorfeaturesofChina’swaterresourcesAnnualrunoffinmm86.458.960.811.024.03.30102030405060708090入海水量（亿m3）50年代60年代70年代80年代90年代近5年不同年代入海水量变化图SharpdeclineriverflowsintotheseaPerCapitawateramountMajorfeaturesofChina’swaterresourcesWaterConsumptiontoavalaiblewaterresourcesin%inChinaAfterDrShaoYisheng，MinistryofConstructionWateruse/wateravailabilityin%MajorfeaturesofNCP’swaterresourcesSummary•NCPisthemostwatershortageareainChinaaspercapitawater300m3only.•Totalwaterwithdrawal:37km3/a(2009)exceedingavailablewater•Overdrawinggroundwaterhasresultedinaquiferwaterdepletionasawatercrisis•Agriculturalwateruseabout25.3km3/a(2009),makingupabout68.5%oftotalwithdrawal•Water-savingisverycrucial中国历年GDP增长87.381010.110.411.611.913.860246810121416200020012002200320042005200620072008统计年度GDP增长比率（％）050000100000150000200000250000300000350000国内生产总值（亿元）增长比率国内生产总值Attribution:Waterstressfromrapiddevelopment:CurrentGDPgrowthisspeedingupincudingNCPregionMainWaterissues:RapiddevelopmentWaterstressfromincreasedwaterdemand:increasedwaterconsumptionpercapita.MainWaterissues:RapiddevelopmentPopulationdensityofChina(Xuetal.)TheNCPhasapopulationofabout0.15billion,accountingfor12%ofChina’stotalpopulation.Thedailywaterconsumptionpercapitahasbeenincreasingfromlessthan0.03m3in1959,tomorethan0.10m3in1995,andtomorethan0.20m3in2000Attribution:Waterstressfromincreasedwaterdemand.Irrigationdemandapproachedalimit.MainWaterissues:RapiddevelopmentIrrigatedareainNCPfrom1949to2008Attribution:ClimatechangeimpactaswarmingupMainWaterissues:ClimatechangeTemperatureincrease:1.1℃forlast50yearsinChinaasanaverageTemperatureintheNCPincreaseabout1.7℃from1960to2010.Increaseintemperaturefrom1951to1999(Wangetal.)TemperatureinnorthernChinaincreasedmoreseriousthanthatinsouthernChinaAttribution:impactofprecipitationdeclineMainWaterissues:ClimatechangeObservedchangeinannualprecipitationfrom1960to2009by753nationalstationsAnnualprecipitationanomaliesintheNCPfrom1955to2009.TheTheaverageannualprecipitationduringwas567.9mmfrom1955to1979,whilethatwas503.5mmfrom1980to2009,decreasedabout11.4%.Attribution:IncreaseindroughtfrequencyMainWaterissues:ClimatechangeIn2010–2011,60yearsrecorddroughthitNorthernChinaThedistributionofDroughtinthespringof2011WheatseedingsthathavewitheredinNCP•Consecutive82dayswithoutraininBeijing,–thelongestperiodwithoutprecipitationin60yearsThirstyDrylandscape86.458.960.811.024.03.30102030405060708090入海水量（亿m3）50年代60年代70年代80年代90年代近5年不同年代入海水量变化图SharplyincreasedwaterconsumptionintheNCPleadtothedramaticdecreaseinstreamflowintotheBohaiseainlasthalfcentury.Annualstreamflowintotheseadecreaseddramatically,from16.10km3in1960sto1.62km3duringtheyears2000to2008,decreasedabout90%.ThestreamflowintoBohaiseainthelasthalfcenturyGroundwaterdepletionintheregionsoftheUS,Europe,ChinaandIndiaandtheMiddleEastfortheyear2000(mma−1).---Wadaetal.,2010,GeophysicalResearchLetters.Groundwaterdepletion--aworldwideissueTheNCPisoneofthefourregionswhichhaveseriousissuesofgroundwaterdepletionNCPGroundwateroverdraft:severinNCPTheNorthChinaPlainisthemajorconsumerofgroundwater,accountingfor44%ofthewholecountry’sgroundwateruse.TheannualgroundwateruseforChinawasabout105.6billionm3,amongwhich92.21billionm3(87.3%)wasconsumedbynorthernChina.TheNorthChinaPlainhasbecomeoneofthemostoverexploitedregionsintheworldAnnualgroundwaterwithdrawalaveragedfrom1997to2008inChina(datacomefromtheChineseMinistryofWaterResources)MainWaterissues:GroundwaterdepletionGroundfissureresultingfromoverdraftofgroundwaterintheNorthChinaPlain(inHebeiprovince）Thedepthtogroundwaterwas11.06metersin1978,andhasbeensubsequentlyreducedto36.12metersin2009,withanaverageannualdeclinerateof0.81metersLong-term(theyearfrom1972to2009)dataofgroundwaterlevelhasbeenrecordedattheLuanchengNationalStation(locatedintheNorthChinaPlain),amemberofGloba