JoumalofHydroscienceandHydraulicEngineering
VoL25,ＮＣ」May,2007,77-88

7７、EVELOPMENTOFADISCHARGEBmASUREhmNTTECHNIQUE
COMBINEDWITHIv頤ＡＳＵＲＥＭＥＮＴＯＦＭＥＡＮＦＬＯＷＶＥＬＯＣＩＴＹＡＮＤＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＣＲＯＳＳ－ＳＥＣrlONALVELOCITYDISTRIBUTION;ＦＩＥＬＤＶＥＲＩＦＩＣＡＩＩＯＮＩＮＡＬＡＲＧＥＲＩＶＥＲ

Ｂｙ
Ｈ・Nakagawa

Resea１℃hCenterfbrF1uvialandCoasta1Disastcrs,、is紐stcrPreventionRescaJChlnst.,ＫｙｏｔｏＵｍｖ.,Kyoto,Japan
ＭＯｎｏ＊

Tbnegawa-KaryuRiverOfYice,KanloRegionalDevelopBuI巳au,MinistryofLand,InfrastructureandTmnsportation，Chiba,Japan（＊presemoEficc:KasumlgauraRjvcrOHice,KantoRegionalDcvelopBureau,MimsnyofLand，

InfiastmctmCandTmnsportatio､,Ibamki,Japan）
MPdaandSNishjjima
River＆ChannelF1owMeasul巳mentDiM,ＪＦＥＡｄｖａｍｅｃｈＣｏ,Ｌｔｄ.,Hyogo,JapanSＹＮＯＰＳＩＳ

Rjverdischaｴgcisaprincipal，auBdasignmcanthydrologi函lquantitvfbrriverplanning，managemcmLandelwlronmentalconsewation．Ｔｂｏｂｔａｉｎｐ泥ciscmcasul巳mcntsofdischargc，techniqUesweredevelopedfbr
detcnniningcross-sectionalmcannowvclocitybyhydroacousticalmcasurcmentoflocalvclocityinconjumctionwith

numericalsimulaUonofvelocitydistribution，ThismewdischaIgcmeasurcmentsystcm`別ＴＥＭ４ｇ,wasinstalledin
theTbneRiveLanditsmeasm己mentperfOnnancefbrariver500mwidevcrified･Theaccuracyobtainedis

comparablctoorbcttcrthantluatofthecommonlyusedvclocityprofilemReverseflowdischaIgeto4,O()０，ﾂswas
continuouslyandstablylneasuredbyATENAS,wher巳ascstimatcddischaugeoblainedbyfloatswasunstablcdlmng
floodingｌｎｔｈｅｃａｓｅｏｆａｈｉｇｈｖｏｌｕｍｅｏｆｄｉｓCharge,thevclociⅣprofilcrunde唾stimatedflowvelocitybThiswas
thoughttobeduetobedloadmotion．
IＮＴＲＯＤＵＣＴＩＯＮ

Theprima1yobjectiveofrivcTplanningistoprcvcntnoods、RjvcrchamuelsaredesigmedsothatwatcrvOhmReflowssccu唾lyuptothedesignllooddischarge、MaintainingadequatenowamormalUmesisalsoanobjectivefbr
properutilizaUon,maimcnanccofnormalriverfimctio､,andenvironmen(alconservationlnmakingariverplan,theriver，sdischargeiscalculaledDPomamnofranalysisbascdonpastrainfnll,watcrlcvcl，waterdemand,etc・TbvcrifythcnmoITmalysis,improvcitsaccumcy,orbotl1,itisnecessaIytomcasulcUme-serics

valiationinthcactualdisCｈａｒｇｅｉｎｏｒｄｃｒｔｏｌｄａｔｃｒｉｖｃｒｆlowtomini311observations・Mcasuringlivcrdischargc，

7８

thcrefbre，isessentialtovariousaspcc[sofrivcrinemanagcmentsuchasdisasterpTevcmion，walerutilization，and
enVirOmTBenta】COnSerVatiOn

RjverdischalgeisusuaUycstimatedfiromwaterleveldHhtabymeansofadischargeratingcurvcdeterminedfipom
anumberofdiscrctemcasurementsobtaimcdbynoatsandprOpeUermeに応(1)．hhasbeempointcdoulthatthis

pmcedul簿ｈａｓｖａ『ioustechnicalpmblcms,andimprovedaccuracyinmeasmmgdischaIgeisl巳quired(2)．Somc
recenUyproposedmeasuringtechmiqucshavcnotprovedtoshowsuHicientr巳nabilityandaccuracytoserveas
altemativeproceduresfbrmaldngstablemeasurementsimIaｪgcnvers

ConscqucnUy,inspitcofitsimporlanceinrivermanagement,【lovalidtechniquefbrmeasuringriverdischaｴgeis
co､RideTedtohavebeenestabljshc｡、

WedevelopedanewtechmqUefbrContinuouslymeasuringnowinlargenversthathasahighaccuracyeven

underfloodingconditionsandhighturbidity･Thistcchniquecombinesthcnumericalsimulationofflowvelocity
distributionwithmcasm巳mentofmeanflowvelocityalongameasurementpathacrosstherivcr，AdischargemeasurcmemsystemnameｄＡＴＥＮＡＳ(AdvancedTEchnologyofL1Umerical5imuIationofvelocity
distIibutionandhydroACousti垣),whichimplcmentsthis胚ewlechniquewasinstalledinUleloweTrcachesoftheTone
Rivertoverifyitsmeasul巳mentperfbnnanceinalalgeriver、ThisdischalgcmeasmcmentsystcmContinuouslymeasulcsriverdischaI晋efiromlow-waternowtofloodingwiththesameorhigherlcvclofaccuraｃｙａｓｄｏｐＩｃｃｉsenowevaluationsmadcbycommonlyuscdvelocitypmfilcls．
PROBLEMSOFmUSTTNGPROCEDURESANDFEATURESOFTHENEWLYDEVELOPEDTECHNIQUESFORFLOWIv胆ASUREIv臣NＴ

EJris【､gルｗ川ｅｑｓｗ"ｍｅ"Jpmcedm“α"d的e〃，'Ｕｂﾙ"jｓa)F1owmeasurcmentobtainedwilhadischargemlingcurve
AdischargeratingcurveisbasedontlBeassumptionthatflowvolumeisuniquclyrclatcdtoacertainwaterlevelvalualnfact,dischargeoftencannotbeexp唾ssedasthemonotonicfilnctionofwaterlevclduetoUdalelfects，

eHectsofalow-gradicmriverbed,weiropcmUon,vcgetationintherivcrchannel,andotherldatcdfactoIB．
b)Disc1℃tcnowmcasurcmemprDblcms

lntheusualdiscrcteflowmeasurcments,localflowvelocity＞Ｐ;,ismcasu配dthcnmulUpliedbyacalibmtion

inc１０回Ａｌ，yieldingthecross-scctionalmeanf1owvelocity、Thisvelocityislhenmumiplicdbylhclocalar己a，』,，
giviIlgthelocaldisChalgc，Lastly>thctotaldischarge，２，i50btaimcdasthcsummationoflocaldischaIges；

ｇ=Ｚｋ,Ｍ１（'）
F1oatscommonlyarCusedtomeasureflowvelocitydmngflooding・SinceindownUWcrflow>f1oatsare
aHbcにdbyflowdisturbanccscausedbypiers,a1ocalstエビamthatproducesaceIlularsecondaIycurTcnts,andotherfactors,theaccuracyandにliabilityofsuchmcasmementsisnotvelyhigh(2)．

Mcasunngsulfacenowvclocitybymeansofradiowavcs,ultmsound,oravideo-camerahasbccnpropo5cdasaltemativestousingfloalsThesetechlniques,howevenhavetwodrawbacks:(i)thcyarcdi価cullloapplyduring
penodsofstrongwind1xeavyminorsno“amdofhcavyfbg.(ii)inprincipletheyhavcdimHcultyinmcasuringlow
Howvelocity

Furthcmlol⑥,witllthesetechniques,suchaswithnoa1s,acalibralionlnctorisrequiredlocvaluatedisChalgc,ｂｕｔ〔hcvalucsofsuchltlctorsalctcnlalivc,andsohavenolbcendctenninedproperlyalprcscnl（１）Thecalibration
fhctorshouldvarywiththedisIributionoffIowveIocityaleachmeasuremc】】tsitc・bultheIenlativevaluesa正7９classifiedonlybywateTdepth・HisalsodifTnculttodetermnethecalibrationfactorfromactualmeasurementsof

inhequentsituatiolussuchasalaIgenood

FiglshowsdischaIgemeasm℃ｄｂｙｆ】oatsatmcasurementsitesalongthelowerreachesofthcTbneRive｢ｗhe肥hydmuMcallycomplexflowoccursｄｕｃｔolidaleE【bctsandthelocally-asymmctricriverbed．

５０００

０００

０００
０５０
４３３

望這］①宮ロニロ⑪一つ』①三匹/漬錨

二二Z;二霞ﾐﾄﾞｷﾞ

……

4500

－－

４５

i;:fft鶴↓u;ドEstua両kbar 『ａlUXm－●司:Fu埴ｗａ－、■２:Ｔａｔ副ｄａｉ
ﾍﾞｺｰａＩＫａｎａｅｔａ」－の南4;KanzaId･･･①-ａＳａｗａｍ

当i鯉瞬？

z5q9:００１２:００１８:０００:ＯＯ
ｌＯ川０

ＭｅａｓｕｒｅｍｅｎｔＭｍｅ

１０ｎ１

Ｆｉｇ・lDischaｴgcmeasu唾dbynoatsalongtheTbneRiver,slowerreachesduringnoodingbylyphoonn0.22,2004..

ThcpeakvaluesofdischargediffergreaUyjuptoaboutl,OOOm3/5,andthcdischargetrmdatcachsiteisnot
smooUlbutfhIctl1乳ｌｅ且

WhcnnowismeasuｴedbasedonthcDopplcreb[bctbytowingavclocilyprofn“itisunnecessaIytodctermine
thcoptimumcaUbrationfactorbecausenowvelocityismcasuredp唾ciselyacmsstheoverallcrosssectionofthcrivcL

Thistecllmiqueisrestrictedtorelativelylownowvelocily、Inpractice,ilisalsohardtocontjnuouslymonitorthe
dischaIge・

Ahorizontalvelocityprofilcrhasbcenusedfbrf1owmeasurement(3),buttherearetcchnicalproblemswith
velocityestimationmnon-measurabIcaTeas，limitationofriverwidth，andmeasulcmentpossibilitvunderhighmrbidjty．

c)Summaryoftechmcalohjectivcsinmcasmngrivcrdischargc
Currcntobjectives…

(i）tomeasu唾localflowvelocilycontinuouslywithahighlevelofaccuracyindependentofsuTrounding
circumstances，(ii)toobtaintheoptimumcalibranionfnctorthatrenectsthevelocitydistributionatindividualmeasulmentsites、

AcombinationoftechniquestoachievetheseobicctivescanlilcilitatemakinghighlyacculzlteandContinuous
dischaIgemeasurementinrivcrs．

犀QrzJ'Ｐ３q/油e〃ewrech"i9皿esi灯肋GArEM4Sd『“んaPgeF"easzJグゼ腕e"［砂s陀腕

Toachievetheaboveobjectives,wedevclopcdatechniquetocontilBuousIymeasurcflowvelocilywithhighaccumcy,eveninIargenvers,whichdocsnotdependonsulToundingcircumstances,andonebasedonamumericalsimulationtodctermineUleoptimumcalibratiomfactor・a)FlowvelocitymeasurementinlalgcIwcTs

AvcmginglocalflowveIocitymeasurementsovcrawidealmusuallVefYbctivclysupprcsscslluctuationcaused

8０

bylocaldisturbances、Theultrasonictmnsittimemethod(1),(4)wasadaptedtomeasulcnowvelocityBythis
method,themeannowvelocityacrosstherivercanbecalcuIatcdfromthcdif[brenceinlhetransittimesofultrasonicpulsestmvelingdiagonaUyacrossthcflowinthedownstreamandup５h℃amdirections、Theadvantageofthismethodisthatessentiallytheve10citymeasuredisnotaHbctedbywatertemperatureor
salinimwhichchangcsthespcedofsoundmwatem
Althoughthcmethodhasbecnmthepracticalusesincethel970s,measure、cntofienhasfniIedintimesof
nood,ofhightuTbidit乳andinlaugeTiversmor℃thanlOOmwide(5)．
Absolptionandscatteringlosscscauscdbysuspendedso1idsaretheplincipalfklctorsoful位asonicattenuationinwater、TheselossesdecrcaseastheultmsonicfrequencyisIoweredA28kHzultlasoniclransducerwithhighoutputwas，therefbre,adoptedinsteadofaconventionallＯＯｔｏ２００ｋＨｚｏｎｅ．AbsorptionofthislowhCquency
ultrasoundinwaterisnegligiblefbｒａｄｉｓｔａｎｃｅｏｆｕｐｔｏｌ,000ｍ、MoreoveLthescatteringattenuationcoefficientof

28kHzultmsound，producedbysuspendcdsolids，ｉｓｏｎｅ－ｔｈｉｒｄｌｈａｔｏｆ２００ｋＨＺｉｆｔｈｅsuspendedsondsizeis
approximatedto20似、(7)IncontrasLthislowerfrcquencyultrasoundhasalongerwavelcngththantheconventionalultrasoundthatis

used、AlaIBerelTorinnowvelociUthenoccursifthetmnsittimeObtainedhaｓａｎｃｌＴｏｒｃｏｒｒ巳spondingtoonc
wavelength

Thismeansthatthesimple,conventionaldctcmUmngproccdunesbasedonasignalamplitudethresholdcannot
bcusedtomcasur⑥flowvelocitywithlowcrultlasomctlansduccrs・Anewdigitalsignalproccssingalgorithmwas，
thereHbre,developedtomeasul巳transit【imecorl巳ctlybytmcingpcakpositionsintheulIrasomcsignaLb)DetclminationofthcoptimmncalibmUonfhctor
Althoughitisdesimbletoselcctthecalibrationfactorbyconsideringlheuowvelocitydistribution,itisdilficult

tooblainbyactualmeasurementsfbranynowregime・Instead，anumericalsimulation,bywhichthcvelocity
distlibutioniscalculatedfbrcvcryconsidelHbleflow，wasintroducedtoobtainthisfilctｏＫＩｎｔｈｉｓｗｏｒｋ，thistcchniqUcisre化r1℃dtoasthcSnVn（calibmtionmethod(8)．
Inthismethod,thevelocitydjstributioninthecmss-sectionatthemeasurementsitcissimulatcdbysolvingthe
RcynoldsequationlbranincompressiblefluidinapropernumeTicalmodeLThesolutionmethod,usingtheFinite
ElementMethod,issuitablefbrmodelingriverchannelsbecauseofitsf1exibilityfbrgencratingcalcuIationmeshes・
Ｆｉｇ２ｓｈｏｗｓａｎｅｘａｍｐｌｅｏｆｓｉｍｕｌａＩedvelccitydistributionmthccmssscctionofthcTbneRiveltFromthis
distlibution,thccalibmtionfactoriscalculatcdaslhcmtiooftheoverallmeannowvclocitytothemeanf】owvelocity

alongtheacousticpathacrossa、Ver．

【

FIowVeIocity

鑿剛.〃

；

-－０lOqＺｐＯ８００dOOOOOＭＩＤＤＬＥ

蕊Low

RiveTwidthIm1

Fig･ZExampleofdislribulionofflowvelocitvinthccrossscctionofthcTbｎｃＲｉｖｅｒｅｓｔｉｍａｔｃｄｂｖｔｈｃＳＩＭＫ
caIibrntiommelhod

￣

ザ

8１

BasedonmanypIwiousanalyses(9),weconfirmedthatthecaUbmtionfactorisdeterminedbylheSIMK
calibraUonmcthodwithanaccumcyof＋/－３％evenifthesimmatedvalueofthenowvelocityisnotexactlyequalto
theactualvalucataccrtainwaterIcvellnothcrwords,thcuscoftherdativedistlibutionofnowvelocib/rather
thanIhemagnitudcofthatvelccityisthcmainfeatureoftheSIMKcalibmtionmethod

The泥lativehei喚tofthcacousticpathvaricswithchangesmthcwaterIcvclassociatedwithdischaIgc,andthe
calibmtionfhctoralsochanges・ThecalibmtionfactoLthelcfbrc,mustbegivenasafmnctionofthewatcrlevcl,ｗ，

andhcightofthcacousticpathd；A(｡,"),bysimulatingthcnowregimeatva面ouswatcrlcvcls・
ThusareliablecalibrationfnctorcanbeobtainedfbranyflowregimebythcSIlvⅨcalibmtionmethodwithout

measuringthenowvelocilydistributionFurthermore,itisnotnecessarytoadjustthemeasu塵mcmsystemto
corT巳Spondtootherdischargemeasurements,anddischargecanbeobtainedjustaftcrinstallaUon
Ｆ匝ＬＤｖＥＲＩＦＩＱＫｒｌＯＮＯＦＤＩＳＣＨＡＲＧＥＭＥＡＳＵＲＥＨｍＮＴＡＣＣｕＲＡＣＹＩＮＡＬＡＲＧＥＲIｖＥＲ

Overwewq/Wheye'1/WJD』F陀恥

ToveIifythemeasu１℃mentperfbnnanceofournewlydevelopedtechniquesundcrflowconditionsfromlow-flow
tolargcnooding,weinstalledanATENASdischargemeasurementsystematSawaraalongthelowerr巳achcsofthe
ToneRjverinitsestualybasin41kmfromtherivermouth・Uluasomctransducerswer巳ｓｅｔｏｎｍｏｕｎｔｓｈｅｌｄｂｙＰＨＣｐｎｅｓｐｌａｃｅｄnearbothrivcTbanks・Theacousticpath
lcngmwas381mnlcacousticpathlayoutisshownmFig3(Y､P､refbrstotheYcdogawaPcilstandardgeogmphic
height)．

］Ｉ’１０１
５

■￣
■仏

０
ｓ

Ｅ．Ｑ，ここｇ■シ⑩一山

Ａｃｏｕｓｔｉｃ palh枠

ローr宅舌･監呂●岩ニロモSPQ二曲＝＝夛埠P香送

ＮＷＬ(ＹＰ+1.14ｍ~ｱｰr､Ｆ〒三一了Ｉ￣

０１００２０ロ３００４００S00

Distance[mI

Fig3HorizontalandverticallayoutsofacousticpathsatSawara

ThercIationshipbctweenlhewaterlevelandthecrosssectionwasdetermincdfmmUlcsuweyedriverbedprofile、

mhecrosssectiomwascalculatcdfｍｍｔｈｅｗａｔｃｒＩｃｖｃｌｂｙｔｈｃｒ巳lationshipinATENAS・Theflowvclocitywas
measuIcdatlO-secondintcrvals,andthedischargewasexpmedtotheriveroffnccatS-minuleintervalsalierObtaining
themovingaveragc･Ｔｈｅｃａ】ibmtionfactorwasafUnctionofwatｅｒｌｃｖｃｌａｓｄｃｌｅｒｍｍｅｄｂｙｔｈｅＳＩＭＫｃａｌibrationmcthodbefb｢cinsIalla1ion,inwhichHowveloci【ywassimulatedindetailwithinana1℃alkmdownslreamand2kmupstr巳amIromthc

8２

measu唾mentsite、ThemughnesscoeffHcientoftheriverbedandthehighwaterchannelwerCchosembasedonU.Ｓ・
GeologicalSurveyにferencevalues(10)．

Sevem1obscrvationsbytowinglhevelocityprofilerwereconductedfmmSeptcmber2004toJanualy2005to
obtainthemeasuI己dmeannowveIocilyaIongtheacousticpalhandthecalibralionflctonMB1ocitypmfiler
specificationsaⅡ己showninTklblel・ＯｎｌｙＵＨｅ唾laliveflowvelociUtotlBeveIocitｙｐｍｆｉleritselfwasmeasuredinthe
towingobservations・Ｔｈｅｎowvelocitymagnitudcwasthencorｅｃｔｅｄｂｙｔｏｗｍｇｓｐｅｅｄａｓｃｖａｌｕａｔｅｄｂｖ
づbottom-tmckingontheassulnptionthattheriverbedwasstationaly
TklblclVelocityplDfilcrspecifications
１１cｍ
Item

Spccification

Type
FrequcnCV
FrCqucncy
CcllwidUu
Cellwidth

50cｍ

20cｍ

Bo1tom-tmcking

０

speed
Ｓｏｈｗａ｢囮Sofiwarc

WinRjvcr

Rangcofnow

５

ofship０

CorIcction

１(RDInstmmenls）
1200kＨｚ

貿伍』①｜準。』ころ一。◎｜⑩シ）ら』ｕｃｌ⑩シ量◎丘

RjoGnYmde

００．５１１．５

highlow-middIe

vclocity

RowveIocity(ATENASxm/s】

Fig4ComparisonbetweenAm垣NASandthcveIocity
pmnlerofnowvelocityateachmcasu”mentheight

Ｍｂ“んwveﾉocj〃αｂ"ｇ鯛eacolUsl化pα肋ａｃｍ甜肋erjy〃a)Compansonwiththevelocitypmfileｒ

Ｆｉｇ４ｓｈｏｗｓｃｏｍｐａｒｉｓｏｎｓｏｆｍｅａｎｎｏｗvelocityacrosslheTivcralmeasuremcntheigh1sfbrATENASandthc

velocityprofilcraleachmeasul己mentpoint、ThcvaluesagIEewelIwithinthemeasurementramgcfirom-O」(reve庵efIow)to0.8m/sTheevaluaUondifTerenceslbrATENASandthevelocilypmlTleraｒｅ‐0.01句-0.02m/sinY;Ｒ-2.5ｍ(Layer＃1）

000＋卜003ｍ/sinYbR-1.0ｍ(Layer#2）
whel巳c1mrisdefinedasastzmfWnrddeviation・

Thismagnitudeoferrcrisequivalcnttothemeasurementunccrtaimyofthetowcdvelocilyprolncr，Therefbr巳，
ＡⅡENASwhjchadoptslowfrequencyultmsoundandsignalproccssingfbrlongwavelcngthsignalscanmcasmcnow
vclocitywiththesameasorahigherlevelofaccumcythanvelociUpmfilertowingobsewauons、Thcvelocityprofn“howcvc凪undc唾stimaにsthcflowvclocityinrangcsaboveO８ｍ/sKimizu,ｅｌａＬ（11）alsolcportedvclocitypmmerunde妃stimalioninahighflowvelocitymngc・TheundeTestimationsarcthoughttobe
causedbywrongbottom-tmckingcorrectionduetobcdloadmotion(】2)．
b)Considcrationofvelocityprofilcrundercstimation

TbveIifythecauseofundc定stimation,themovingspeedofthebedloadiscvaluatedbymeansofmcasu唾dvclocitypmfilcrdata

T1leshipvelocitycompoIlentinthedi唾ctioIuoppositctoflowisassumcdtocorYBspondtolhcmovingspceｄｏｆ
ｔｈｅｂｅｄｌｏadThemeanmovingspccdoftllcbcdIoadisestimaledbWwclngingtheshipvelocilycompoIuemlalong

8３

thetowingpathEstimatedbedloadspeedvaluesalecompalCdwiththemeanflowspeed，Ｕ`，insidethcbedload
layerascalculatcdbythecquaUongivenbyEgashira(13)；

“

凧

４｜西

凹面

(2)

ｗhe妃Ｕ・＝mctionvelocity；丁．＝dimensiomesstractivcfbrce・Theothervariablesineq(2)are

Ⅸ罎志雨L耐;腫軋÷('÷)M‘

ﾙｰﾙﾙｮﾙﾙ)E'',Ｍ,=k,に)W'万一2個

等T775LTF雨:砦;雨;再÷

ｗｈｅｌｃＢ＝rivcrbedgradient；ｗ＝waterdepthVhluesofpammete函mthcsceXplcssionswe泥‘＝34゜，c・=0.52,ｅ=q85,ｋ`=00828,Ａﾉｰ0.16,ヶ/p=2.65,as1℃portcdbyEgashira、ThebedloaddjameteratSawarawas
q21mmaccoldingtofieldsuweyresults，Theriverbedgradientwasl/10,000.Thewaterlevelwassubstitutedfbr

thehydrauliclndius、A1ogarithmicprofileisassumedinthcle1atiomshipbetwecnthemeaｎｆｌｏｗａｎｄ瞳ction
velocitiesbecauscthewaterdepthisthoughttobesufTicicnUygreaterthanthclaycrthicknessofthcbedload･Ｔｈe
equivalcntroughnesscoefTicicmselcctedwas48mmtoadjustthecalculatedtoestimatcdvalues・Theestimatedandcalculated”sultsfbrbedloadmovingspeed…ploUedagainstmeanflowvelocityinFig5、EstimationsObtainedhomtowimgobservationsarcconsistentwithcalculationsmadebyeq.(2),providingevidence
lhatthebedloadwastranspoltedataflowvelocityofmor℃than0.8ｍ/satSawaraontheTbneRjvcr、ＴｈｉｓｎｎｄｉｎｇｓｈｏｗｓｔｈａｔｉｎｔｈｅｃａｓｅｏｆhighnowspeeddischalgcmcasumementsObtajncdbytowingavelocityprofnlerofienalea雄ctedbybedloadmotion・SuChmeasm巳mentenurcanbcavoid巳｡;ｅ9.,ｂｙｕｓｉｎｇａｄｉ医rentialGPSIatherthanbottom-tmckmgtocomecttheshipvelocity(14)．

Ａｓ，inprinciple，ＡＩＥＮＡＳｉｓｕｎａｍＩｅｃｔｅｄｂｙｂｃｄｌｏHdmoUon，ｔｈｅｄｅｖｉａＵｏｎｉｎｎｏｗｖｅｌｏｃｉｔｙｉｎＦｉｇ４is
considc雁dtoshowtheafTbctonvelocityprofilertowingobservationsproducedｂｙｂｅｄｌｏａｄｍｏｔｉｏｎＴｈｅｍｃａｎ

ｍｏｖｉｎｇｓｐｅｅｄｏｆｔｈｅｂｅｄｌｏａｄｉｓｅａｓｉｌｙｅｓｔｉｍａｔｅｄｉｆＡＩ垣NASiscombincdwithavelocityprofilerwith
bottom-tracking．

４３２Ｊ０』◎で⑩⑩（称⑤Ｅ一言Ｅ巨呵の二

０［響］別・一で卸

MeanfIowvdocIty{m/S］

FigSBedloadmovingspccdsc5timatcdbythevclocityprofiler
Cセノibmjj･"/bcro’
Tbcheckthevalidity ofthccalibrationmclordetermined，somevelocityprofilcsof5imulatedandaclual
measuremcntsａⅡ巳compa定disevaIuatedby

Basedonlhecalibralionlaclordefinition,theverticalprofilcofnowvelocily，し〔。），

8４

咽而烏‘

（３）

whcrcltOl,'''）＝Ulcvemticaldistributionofthccalibra【ionfactordctcmlinedbylheSIMKcalibra1ionmcthod；ｇ＝thedischa】gemeasuredbyAI垣ＮＡＳ;ａｎｄＡ＝thcchannelcrossseclion・

TheverticalPronlesoftheflowvelocityevaluatedbycq.(3)fbrvariousdischargevaluesaIccompa正dwith
thoseobtainedbythevelocityPmfileRFig6showstllattheevaluatedve1ocityproH1esagreeweUwiththeactual

measuredProfilesfOrdischalgesfiFom-150to1,400㎡/s,inwhichthevelocitypmfilcrwasnotaiIectedbybedload
motionThcSIMKcalibrationmcthodtherefbrewasfbundtosimulatethedistributionｏｆｆｌｏｗｖclocityinariver

channelwithsu飯cientaccuracyConsequenUyぅｔｈｅcalibrationfnctorisdetelmjnedbythismethodunderanynow
condMmn

Ｅ１．ここ◎潟シの｜山.、△虹］、４０．５０－２

MeannowveIocityacrosstheriver【ｍ/s】

Fig6VerticalprofiIesofmeannowvelociUacrossthcTbneRjvcr
DisClm壇②

Asrepoltedinthcprcvloussections,themeannowvelocityatthemeasurememheightismcasurcdaccuratelybｙ
ＡＴＥＮＡＳ，andtheoptimumcalibrationfactorｃａｎｂｅｄｅｔｅｍｎｎｅｄｂｙｔｈｅＳＩＭＫｃａｌｉｂｒａtjonmcthod･Inthissection，djschargeisexamincdtoverifytheovemlImeasurementperfbnnancesofthesetechniqueslnmeasuremcntsobtainedbyvelocityprofilertowingfIowvelociUesinunmeasurablcar巳asnearthewater,ssurfnce,theriverbed,andbothrivcrbankswereestimatcdbyextrapolaUon

AcomparlsonofdischaIgesobtainedbyAIENASandthetowcdvclocilyprofilerisshownmFig.7．The定isobviousundcl巳stimationbythcvclociWpmfilerduetobedloadInotionatmorcthan2,000,3/s・Incontrast,fbrdischaIgesbelow2,000㎡/s,ATENASyicldsalmostlhesameaccuracyasthetowedvelccityprofileEindependentof
nowdirection・ConsequenUy>bycombinjnglow丘equcncyultrasound,sig既alprocessingsuitablefbrlhclongwavclcngthsignal，
andnumclicalsimulationtoobtamtllcfIowvelocitydistribution,riverdischargecanbem図suredconIinuouslywhha
highlevelｏｆ日ccumcy,evcninlargenvers

ThecstimaleddischargcmcasmcmemermrfbmdKrENASisaslbllows・Ｔｈｅ虚lativcm園surementcrrorfbrnow

velocityis-V-0.6％basedonsampUngcrmrindigitizingthc泥ccivedultrasomcsignaLTheldativeuncertaintyin
thecalibrationihctordetenninationisabout＋/-3％basedonpastSIIVm（calibmtionmethodresuIIs(9)．Therclative

uncertaintyincalculatingthcchannelcrossscclionisaboul＋/-1％bascdontheriversurvey，saccuracy．

8５

Consequently,the【datjvcuncertaintyofriverdischalgeobtainedbyeq.（１）is＋/-32％、Thisuncerlajntyisr巳duced

byavemgingthemeasHmCdvalues、Forinstance,iffivemeasul巳dvaluesareaveraged,weexpecttheunccrtaintyof
mcasuエビmcnttobc329W百三14妬．
4000

少
グ

ジ
ジ

０
０

０

辺宅一罰①一』Ｅ○畳⑨Ｃｌのシ｝①巨甸二８一℃』のシ一匹

グ
グ

グ
グ
グ
グ
グ

ゲ

ゲク’ＯＯＯＯＯ
グ

〃

０

０

０
２

夕

’

ン

０

０

０

１

ジ

’

,‘

’
‘
ジ

０
’

〆

０１０００２０００３０００４０００

RiVBrdIscharge(ATENAS)【､｡/S］

Fig7CompansonofrivcrdischaIgebetwccnAIENASandthevelocilyprofiler●

ＤＩＳＣＨＡＲＧＥＭＥＡＳＵＲＥＭＥＮＴＤＵＲＩＮＧＦＬＯＯＤＩＮＧ

OnOctobeT6tlL2004,immedialclyancrtheinstallationｏｆ八ＩＥＮＡＳａｔＳａｗａｍｏｎｔｈｅＴｂｎｅＲｉｖｅＥｔｈeKanto

re巴onreccivcdton吟nUa1rajnm111bllｏｗｅｄｂｙｔｈｅｂｍｍｏｆｔｙｐｈｏｏｎｎ0.22．

ReprcscntativcresultsofcontinuousunmanncddischaIBemeasuremcntsbykIENASduringthjspeliodare

showninFig8．（TENASclearlycontmuouslymea5u正ｄｔｈｅｄｉschalgefiromalmostOtomorcUlan4,000㎡/S
withoutmeaSmcmentfhilurc．

Ｔhefigurcbelowalsoshowsthediscr巳tedischargemeasurementsmadebyfloatsandatowedvclocitypmnler、
FmmOctober6thto7tlLtlleth１℃ekindsofmeasuI巳dvalueswcrealmostthcsamc,butthedischargevaluesobtained

bythcnoatswererelativelylaugeFromOctobcrlOthtollth,thepcakdischargevalueswiIhthetowcdvclocity
pmfilerwe1℃und罪stimatedbyabout３０％asstatedpIwiously・F1oatmeasuIcments,howevcZSqillovcrcstimatedlhedischalgCascomparedtoA｡ＥＮＡＳ・Fhmhermolc,。ischaJgeasmeasuredby八rENASincreasedanddecICasedsmoothly(Fig」),whcreasthatmcasuredbyfIoatsnuctuatedgr巳aUy,cxccptalFukawawhercthcreisanarmw
scgmcnt．

塁鳥､､黒１１冊;ﾅﾐi＜
軍議橇鱗,,,.`）
y>1.0m/ｓ

MeanfIowvOIocity<0.8m/ｓ

ム丹旬〕冗笙。Ｉ〔Ｕ

０００００

００００

［辺宅］①曰面宍厨宕』堅達㈹釦、⑩、Ｓｔａｔｉｏｎｎｅａ「Ｓａｗａｍ－－－幽四ｉｎｑＷ蝕暫｣Qy2jgLYQ｣92jqngSg型､g｣a2angqqp旦卓p幽咀＿

Ｅ・Ｑ・己ロ』ロ」冑の｝■｜①３｜』里ロー

５０００

2004/１０/４１０眉１０/６１０/７１０/８１０/９１０/1０１０/1１１０/1２１０/1３１０/１４，ate

Fig.８Measureddischargcandwaterleveloblajnedby八rENASinslalledatSawamontheTbmcRiverundcrtonmtial
mmandlyphoonno22inOctober2004

8６

Ａｓｆｂｒｔｈｅ肥lationshipbetweenwaterlcve1anddischalgc,firomOctober4thto5thpenodicchangesinwaler

levelscauscdbvlheUdewelEobserved;moreovcndischargewiththewatcrlevelchanged,havingaphaselag・Ｔｈｅ

tide，sefIectonlhewatcrlcvelanddischaUgercmaincdduringthcdeclimcinnoodingafterOclobc「１１thDischaIge
clearIywasaHbctcdbｖｔｈｅｔｉｄｅＴｈｅ歴laIionshipbetwccnrivcrdischaIgesandwatc「lcvelsdcfinitelycanbc
measuI己dbycontinuousobscrvationslikcthoscofthcAIENASdischaIgemeasurementsystem
lnaddilion,typhoonno､23,whichpassedoverthcKantoarcalalcrinＯｃ【obencausedasimilarnoodinwhichthcpeakdischargcro5eto4,000㎡/s・Atthatlimc,八rENAScouldmeasurelhedischalgccontjnuously.
ＣＯＮＣＬＵＳＩＯＮＳ

Anundemandjngactualrivcrdischargcisve『yimportantfbrcxamlmngandimprDvlngmnofranalysisaccumcy
inriverdesign・Stablemeasu塵mentofnowvelocity,泥gardlessofsurToundingci亜umstances,anddetcnninationof
theoptimumcalibrationfactorthat唾､cctslhenowvelocitydistributio、undcrthenowcoIRdilionsisessentialtothe

measu蛇mentofriverdischarge、WecombincdanumericalsimulationortheHowvelcciIydjstributionandnow

vclocitymeasurclncntusmｇｌｏｗｆｉ巳quencyultmsoundanddcvelopedthcATENASdisChargemcasurcmemsystem，
whichinco『poratcsthenewtechniques,toContinuouslyObtainthcdischargcwithahi邸1evelofacculacy、Discharge
valucsmcasurcdbyATENASinstalledatSawaraontheToneRjverwc肥compal巳dwmhthoseobtaincdbylhcuseof
lloatsandatowcdvelocityprolilerinoldcrtoverifymcasuImenlpcrIbrmancc・OurconclusionsarcaslblIows：(1)TheadoptionoflowfequencyultrasoundintheultrasonicIramsitlimcmeU1odimpmvedlransmiltingperIbrmanceinlargctuIbid｢ive応,anddevclopmenloflheaddiUonaIsignaIploccssingaIgoritlunfbrlongwavclcngthultrasound

impmvedthcaccuracyoftransitUmcmcasu雁mcnts・AsaresuIt，flowvelocitycanbcmeasurcdcontinuously
withthesameorahigherlwelofaccumcythanbytowingavelociIyprofiIer．

(2)ThcdistributionofnowvelocityinarivcrchannelwasfbundtobceslimatedcorrectlybytheSIMKcalibration
methodbasedonmumericalsimulationThecaliblationIncIor,delinedastheratioofthecross-scctionalmean

nowvelocitytothelocalflowvelocity,theTCfb泥canbcobtaincdwithsufTicientaccumcyfbrpraclicalｕｓｅｓ(3)ThecombinationoftheATENASdischargemeasurementsystcm,whichmeaslmesnowvelocilybythelow
frequencyultmsonictmnsiltimemcthodandestimatcstheflowvelocitydistributionbymeansofnumericalsimulation，withoutfailuremeasuIcs【iverdischargefiPomrwerscnowtonoodinｇａｔ４,OOOm3/ｓｉｎａｌａＩｇｃｎｖｃｒ
ａｂｏｕｔ５００ｍｗｉｄｅ・Themeasmementaccuracywasfbundtｏｂｅｔｈｅｓａｍｃｏｒｈｉｇｈｅｒｔｈａｎｌｈａｔｏｆｏｔherexistmg
dischargemeasurementにchniqucs．

(4)Ifthebedloadmovesduringhighflowdischarge,towingmeasurementbyavelocitypmfilerofienundercstimates

thenowvelociIyandnowdischargcduetoincorIectevaluationofthcshipspeedbyboltom-tmcking、Inprinciple，
lhcATENASdischargemeasuにmentsystemisnotafIectedbysuchbedloadmction(5)Thcmcanmovingspccdofabcdloadcanbcobtainedbylowingmeasurementwithabottom-trackingvclocitv
pmfIlerincombinatioｎｗｉｔｈＡＴＥＮＡＳ・

Asdescribcdabove，themeasu紀ｍｃｎｔｐｅｒｆｂｒｍａｎｃｅｏｆＡＩＥＮＡＳｗａｓｔｅstedmanactuallaIgenverunderfloodingandnormalnow・Anexaminationofmeasurementpcrfbrmanccunderhightulbidityandmeasmcmentof
lhedischaIgeofapartiamoWduetointrusionofasalt-wedgearesubjccIsfbrlUtulestudy．
RＥＦＥＲＥＮＣＥＳ

1．MinistIymanualmrriverworksinJapan（Survey)；prelimnalywiIhdescripUons，配viseded，JapanRjver
AssociatiomTbkyo,Japan・’997.(ｉｎJapanese）

8７

2．Fukami,Ｋ､,Amouj.,Ohte,Ｍ､,andYOshitani,叫庇chnicalsubjectsandnewdevelopmentstowardaccumcy
improvementofriverdischmBeobsc｢vations，CMlEnginccnngJoumal，VbL45，ＮＯ２，ｐｐ､22-29,2003．（ｉｎJapanese）

3．Okada,Ｓ,,Mori,Ａ､，Umjno,Ｓ,ＫＯ､,Ｔ,andYmnada,Ｔ：Discha唱eObsewationatTnmmiRｊｖｅｒＵｓｉｎｇＨ－ＡＤＣＰ

ＡｕｔｏＳｃａｎｎｍｇsystem,AdvancesinRivcrEngineenmg,Ｖｂ1.11,ｐｐ243-248,2005．（inJapancscwithEnglis】D
abstmcO

4・ＩＳＯ6416:2004Hydrometry-MeasmEmentofdischargebythculIrasomc(acoustic)mcthod,Geneva,Switzcrland，
2004.

5．Hachiya,Ｈ､,Wang,Ｙ,andKiIBoshita,Ｔ：EstimationofthestabjliWofacousticmultipathsignalintherivenl
MarineAcoust・ＳＯＣ､Jpn,Ｖｂ1.28,ＮｏＬｐｐ､34-40,2001.(inJapanesewithEnglishabstlact）
6．Urick,Ｒ」.：Principlesofunderwatersound,３rd.ｃd､,PcninsulaPubIishing,LosA1tos,ＵＳＡ,１”6.

7．Lac恥CIU,Ａ,,ａｎｄSmith,Ｗ：AcousticsystemsfbrthemeasuICmeHItofstreamfIow;UnitedStatesGeologicalSurve肌ReportNo.82,DenvenUSA,1982

8．K6Uing,Ｃ：Mcthodanddwicefbrmeasuringthedjscha【geinpartlyfilledoTcompletelyflllcdductsandinopcn
chalunels,ＥＰＯ６８１６８３Ｂ１，1914.

9．KOlIing,Ｃ：SIIVE（－CalibraUonofstreamHow-Gaugingsialionsinnversandcanals,sthlnLConflnnovalionin
HydrauIicE価ciencyMeasmCment(Luccme),No.11,2004.

10．http:〃wwwTcamnLwmsgs,gov/SWS/fieldmethods/Indi庇cts/､values/

１１．Kimizu,Ａ､，Nihei,Ｙ，andMcchizuki，Ｋ、：CompansonofnooddischaIgebetweｅｎｍｅａｓｍＥｍｅｎｔｓｂｙｎｏａｔｓａｎｄ
ＡＤＣR60thJSCEAnn.Ｍt9.,2-257,ｐｐ513-514,2005.(ｉｎJapanese）

12．Rennic，ＣＤ.，Milla瓜ＲＧ，ａｎｄChurch，Ｍ、Ａ：Ｍcasurcmcnto「ｂｅｄｌｏａｄｖｅ】ocityusmganacousticDoppler
cur旭InproflleLJ､ＨｙｄｍｕＬＥｎｇ,Ｖｂｌｌ２８,No.5,ｐｐ,473-483,2002

13．Egashira,Ｓ､：ScdimentiSSueSinrivc｢sandmechanicsofsedimcnt(ransportaUon,ＡｎｎＭｔｇ,Jpn・ＳＯＣ・F1uidMCch、
2005,AMO5-KN-OOl’2005.(inJapancsc）

14．Simpson，ＭＲ：DischargemcasuJ巳mcntusingabroad-bandacousticDopplercurICnlprofileEUmitedStatcs
GeologicalSuweyOpcn-FileReportO1-LDenvenUSA’２０OＬ

ＡＰＰＥＮＤＩＸ－ＮＯＴｍ､IＯＮ

Thefbllowingsymbolsarcusedinlhispaper：Ａ＝nverchamlelcrossscction；ＪｌＩ＝１０(almeasuremcntarCa；

Ｃ．

＝volumeconcentmlioninamovingbcdloadIayer。

＝verlicaldistanccfTomlhewatcrsurlaceloacousticpalh；A、,ｗ）＝calibmtionfncqorasafimctionof付andll】ewaterlcvel；●Ａｉ＝calibHationIhctorinUlelocalmemsuTemenIarca；ｇ＝riverdischarge；

ＵＪ＝ｎｏｗｖｅlocityinsidcthebedIoadIayer；

Ｕ．

＝hictionvelocity；「(。）＝vcrticalproflleofflowvelocity；

8８

昭ｗ９Ｐワ箆肋了＝ｎｏｗvelocityinthelocalmeasmcmenta鑓a；＝waterdepth；＝Iiverbedgradientj＝bedloaddensity；＝waterdensity；＝dimensionlesstmctivefbTce;ａｎｄ＝intemalfrictionangIe．

(ReceivedAugust2,２００６;revisedDecember27,2006）