FIELD OBSERVATIONS IN THE TIDAL ZONE OF A FROZEN RIVER

Transcription

1 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) FIELD OBSERVATIONS IN THE TIDAL ZONE OF A FROZEN RIVER Y. Yshik nd Y. tnb, Ciil Engining Rsch Institu f Cld Rgin, Higishi -, Tyhi, Spp, 6-6, Jpn ABSTRACT Hydulic phnmn in fzing s in th tidl gin f i difficult t bs, s ths ccu in th sst pt f in nd bscud by ic shts. Much but such phnmn mins t b clifid. Ou study usd fild bstins t clify hydulic phnmn in such i. Fild bstins cid ut t css-sctin in th tidl gin f th Tk Ri in Hkkid. Obstin s cnducd duing th fzing pid (th dy f th full-mn fld tid in Fbuy, nd th dy bf nd f it) nd duing th pn pid (th dy f th full-mn fld tid in August, nd th dy bf nd f it), t btin dt f cmpisn. lls msud immdily upstm nd dnstm f th css sctin. At th bstin css-sctin, fl lcitis msud using n custic Dppl cunt pfil (ADCP), nd slinity s msud. Bsd n bstins nd nlyss f th dt, cmmnlitis nd diffncs btn th fzing (ic-cd) nd pn pids idntifid. On cmmnlity is tht th stm cnlin shifts ith th tid. On diffnc is tht th dictin f th pimy fl in th fzing pid diffs gtly fm tht in th pn pid. INTRODUCTION Hydulic studis n th tidl gin f i shuld ddss slt intusin, hich is functin f mphlgy, fsh fl nd slt fl. Such intusin in i tht fzs is thught t b significntly influncd by th fzing, but tht influnc is difficult t msu by using th cuntly mplyd mthd, hich is th sm s tht f pn, bcus ic shts mk it difficult t msu th fl lcity distibutins. Much but th cmplx hydulic phnmn in th tidl gin f n ic-cd i mins t b clifid. Ou study tmpd such clifictin by fild bstins f fl nd th hydulic chcistics in in in th tidl gin f th Tk Ri in Hkkid. F cmp- --

2 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) ll gug - Okhtsk S - ll gug - Obstin css-sctin - Rctngul pln cdin sysm y xis (m) Figu Obstin sis t th l chs f th Tk Ri * - KP. KP. - Eltin (m) KP. - KP Obstin css-sctin - KP. KP. KP.6 KP. KP.6 - KP. KP. KP. - KP. KP * Rctngul pln cdin sysm x xis (m) Figu Bd ltins t th l chs f th Tk Ri ti nlysis, simil bstins pd in summ t th sm lctin. Ech th-dy bstin pid s chsn t includ full-mn fld tid. OUTLINE OF THE FIELD OBSERVATION Obstin sis Fild bstins cnducd in th tidl gin f th Tk Ri in Hkkid. Th i (chnnl lngth f km; ctchmnt f, km ) s chsn bcus th is sttin f bsing slt intusin nd th i fzs in in. Th i, th bstin pints, nd th kilm pints (t.-km inls) shn in Figu. Th i muth is th fnc pint nd its kilm pint (KP) is. Th bstin ims indicd in Figu discussd l in this pp. As shn in Figu, th bstin css-sctin is n th upstm sid f lg bnd. Figu is tp i f th i chnnl, ith cl cntus shing th i bd ltin. Th ltins btind in Dcmb using suy ch sund nd GPS suying. Th chnnl is shn t h dp spts t th xit (KP.6), middl (KP.) nd ntnc (KP.) f th bnd. KP.6 is xtmly dp. It is ssumd tht ths dp spts nd t tp th slt tht intuds upstm lng th ibd, thby sling th upstm pgssin f intuding slt. --

3 Obstin ims Obstins cnducd lng th csssctin shn in Figu. Fl lcity s msud n nin ticl lins n th csssctin. mptu, slinity nd dnsity msud t th thlg. (Th thlg is th dpst spt in i-chnnl css Figu Digm f bstin sctin.) ll s msud t n pint upstm nd n pint dnstm f th css-sctin. Figu digms th msumnt mthd f th fzing pid. Fl lcity In Figu, th css-sctin is diidd by nin ticl lins, n ch f hich fl lcity distibutin s bsd t ticl inls f cm. Equipmnt usd f this includd n ADCP (khs Sntinl khz Zd-Hd, RD Instumnts, high-slutin md). Msumnt s cntinud f scnds p ticl lin, nd th msumnts gd. Th msumnt ccucy s. cms. mptu, slinity, dnsity nd ll Msumnts f mptu, slinity nd dnsity md lng th ticl lin t th thlg (Figu ) using n Alc Elctnics Mmy STD (ATU-PK). ll s msud m upstm nd dnstm f th css-sctin cntinuusly (t -minu inls) using Kshin Dnki Kgy ll gug ith dt lgging ftu (MC-A). Th msumnt ng f th ll gug is - m, ith n ccucy f ±cm. Obstin pid In, bstins cnducd f pid f th tidl cycls ch in th ic-cd ssn nd in th pn ssn. Ech bstin cd Pcdings h th th IAHR Inntinl Sympsium n Ic (6) Tbl Obstin dt () Pid Stt End T.L.D(m) Fzing n n. Opn n n. Duing bth pids, bstin cd th tidl cycls. cycl f full-mn fld tid. Th bstins md tims in ttl th tims ch t high tid nd l tid f ch cycl. Tbl shs th bstin dtils. Th T.L.D in th tbl mns th diffnc btn th high nd l lls duing th full-mn fld tid. Obstin ds nd tims Figu shs th bstin ds nd tims, i bd ltins, lls, nd s f ll fluctutins duing th ic-cd nd pn bstin pids. Ds nd tims, tnss distncs, ltins nd s f ll fluctutins spctily indicd n th bttm hizntl xis, th tp hizntl xis, th lft ticl xis nd th ight ticl xis. Obstin hu in th figu psnts th mn tim f ch bstin sssin. Ech bstin sssin is indicd s succssi numb, in d f th sssins, ith f sssins duing th ic-cd nd s f ths duing th pn- summ. Th g chng in bd ltin t th css-sctin s -. m f th ic-cd nd f th pn. As tht lu is cnsidd ngligibl, bd fluctutin s xcludd fm th list f ibls t b cnsidd in u cmpisn f th t bstin pids. --

4 - n ti l E CVGTNGXGN=O? DUGTXCVKQPFCVGCPFVKOG $GFGNGXCVKQP=O? Tnss distnc 6 D Pcdings h th th IAHR Inntinl Sympsium n Ic (6) CVGTNGXGNHNEVCVKQPTCVG=OJ? h n ti c tu flu l l n ti l E CVGTNGXGN=O? DUGTXCVKQPFCVGCPFVKOG $GFGNGXCVKQP=O? Tnss distnc CVGTNGXGNHNEVCVKQPTCVG=OJ? ) Fzing pid (in) b) Opn pid (summ) Figu Tim-sis chngs in ll nd ll fluctutin (css-sctin) OBSERVATION RESULTS Tidl nd lls Figu shs th cltin btn th tidl ll msud t th Abshii bsty nd th ll t th bstin css-sctin. Th dt huly dt nd th dt pints cnncd ith lins t indic th tim d. Th ltinship shn in Figu cn b summizd s flls. Flling tid... Th dt pints lng th lin f Y=X s s. 6s. l l. -. s D s A clckis cycl f dcs nd incs ith tim s s Fzing pid Opn pid h n ti c tu flu l l Tidl ll Figu Cltins btn tidl nd i lls Rising tid... ll iss This indics tht th is clckis bilnt ltinship btn th t pids, ith tidl nd lls ughly qul xcpt duing slt intusin, hn th i ll iss. This suggsts tht, bing ny significnt chng in fl, th i ll cn b stimd bsd n th tidl ll. -dimnsinl fl lcity Slt-intusin-inducd chngs in fl lcity msud using n ADCP t 6, nd (ic-cd pid) nd t s, s nd s (pn- pid), nd thn sld int th-dimnsinl cmpnnts. Figu 6 shs th th-dimnsinl cmpnnts f fl lcitis f ic-cd nd pn- pids. Th hizntl xis psnts tnss distnc, nd th ticl xis psnts ltin. Fl lcity nd dictin shn using cl cntu plt, nd th fl lcitis in th tnss nd ticl dictins shn using cts. Th gphs f high tids includ hizntl lin indicting th bundy btn fsh nd slt. Lgnds usd f th gphs th sm f th ic-cd nd pn- pids. Th dnstmd bing s btind by ging th bings msud ith ADCP, hich in th ngs f t dgs nd t 6 dgs. Th btind bings in th dictin f th i muth. Th dnstmd bings btind f bstins shn in Figu 6 6 dg f th fzing pid nd dg f th pn pid. Th bundis btn fsh nd slt in Figu 6 btind by clculting th ch innsity f ADCP t slinity f psu, nd cnncting th ltins (m) n th nin ticl lins t hich th slinity s psu. -6-

5 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) Eltin Eltin Tnss distnc Tnss distnc ) 6 L tid (Fzing) ) s L tid (Opn) Eltin Slt-fsh bundy Tnss nd ticl fl lcitis s Dnstmd fl lcity s Eltin Slt-fsh bundy Tnss nd ticl fl lcitis s Dnstmd fl lcity s Tnss distnc Tnss distnc b) High tid (Fzing) b ) s High tid (Opn) Eltin Eltin Tnss distnc Tnss distnc c) L tid (Fzing) c ) s L tid (Opn) Fzing pid (bing f pimy fl 6 dg) Opn pid (bing f pimy fl dg) Figu 6 -dimnsinl fl lcity duing fing nd pn pids Fl lcity nd dictin Initilly, th stm cnlin t th bstin csssctin s thught t b cnstntly n th lft-bnk sid f th chnnl, bcus th thlg in th bnd is n th lft-bnk sid f th chnnl. H, th bsd fl lcitis nd dictins suggst tht th stm cnlin chngs its lctin ith chngs in tidl ll. Th stm cnlin shs th flling chngs (Figu 6). ) At l tid, th stm cnlin is lcd n th lft-bnk sid f th chnnl, th sm sid s th thlg (fcd x). (S 6 nd s in Figu 6) ) At ising tid, th stm cnlin is lcd in th middl f th css sctin, ith th ll fl lcity css th css-sctin hing sld dn. ) At high tid, th stm cnlin shifts n th ight-bnk sid f th chnnl. Th is diidd int th upp ly f fsh singl-sctin fl nd th l ly f slt. Th fl lcity f slt t th bundy btn th slt nd fsh is g tht t th l ptin f th slt ly (f x). (S nd s in Figu 6) ) At flling tid, th stm cnlin is t th midpint f th css-sctin, nd th fl lcity incss t ll pints in th css-sctin. ) At l tid, th stm cnlin tuns t th lft-bnk sid f th chnnl, th sm sid s th thlg (fcd x). (S nd s in Figu 6) --

6 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) Tbl Ag lu f bing f ch fl css-sctin Th bing L tid High tid, Dnfl High tid, Upfl L tid dnstmd f ch fl 6,s,s,s,s bings(g ) Fzing pid 6 6 Opn pid This shift f th stm cnlin s bsd bth in th ic-cd nd pn- pids; thf, it is cncludd tht ic shts h lmst n impct n this shifting f th stm cnlin. It is ssumd tht this shift f cnlin is cusd by shift fm fcd x t f x, nd th shift pps t b inducd by th dcs in fl lcity cusd by slt intusin nd th chngs in sistnc stuctu cusd by th fmtin f fsh singl-sctin fl. (S nd s in Figu 6) Tnss nd ticl fl lcity distibutin Duing th pn- pid, cunclckis hlicl fl s bsd n th stm cnlin t l tid. Hlicl fl s ls bsd t high tid in th upp ly n th stm cnlin, lthugh th s lmst n fl in th l ly. Duing th fzing pid, n hlicl fl s bsd cncuntly ith fst fl tds th utsid f th bnd t l tid. At high tid, fl tds th insid f th bnd s bsd in th upp ly, ith th fl bing fs n th stm cnlin, cncuntly ith fl tds th lft bnk in th l ly. Th dnstmd bings xmind, fcusing n th fl td th utsid f th bnd t l tid nd th dnstm fl n th insid f th bnd t high tid duing th fzing pid. Tbl shs th g lus, th bing f ch fl t th bstin css-sctin. Th tbl ls shs th dnstmd bings. Th diffnc btn th bing f ch fl nd th dnstmd bings t l tid duing th pn pid s dg, hil it s dg in th fzing pid This suggsts tht th s substntil shift in th dictin f pimy fl duing th fzing pid. T clify this shift, th bing f th pimy fl t l tid s xmind. A lin s dn btn th thlg t KP. nd tht t KP., th t pints n ith sid f th bstin css-sctin. Th bing f th lin s dg. Fm Tbl, it is suggsd tht th dictin f th pimy fl is fm th thlg tds th utsid f th bnd duing th fzing pid hil it is fm th thlg tds th insid f th bnd duing th pn pid. Dnfl t high tid hd th flling dictin. Dnfl s fm th thlg tds th insid f th bnd duing th fzing pid, hich is ppsi t th dictin f th dnfl t l tid, nd it s tds th insid f th bnd duing th pn pid. Th dictin f th upfl t high tid s nly th sm duing th ic-cd nd pn- pids. Fm this, it s cncludd tht th shift in th dictin f th dnfl fm insid f th bnd t th utsid f th bnd t l nd high tids duing th fzing pid is du t substntil chng in th dictin f th pimy fl cmpnnt. Althugh tnss nd ticl fl distibutins cmplx, th bstin nd nlysis cnducd f this study s bl t dmin tht th dictin f dnfl duing th fzing pid chngs f g thn duing th pn pid; thus, hlicl fl is cnsidd lss likly t ccu duing th fzing pid. --

7 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) Tbl Fl lcity (dnstmd) f fsh nd slt At high tid V V H ɛ K K in in s Summ s Summ SALTATER INTRUSION Fl lcity f fsh nd slt Using n xpimnt-did fmul() f clculting th fl lcity f fsh nd slt, th sistnc ncund by fluid is discussd. V = K ɛgh, V = K ɛgh () V fl lcitys, Kcfficint, g.s, H dpth, ɛ(ρ -ρ )ρ, ρdnsity[tm, Suffixs nd spctily f t fsh nd slt. Bsd n th b, K nd K btind (Tbl ). F this, th mximum fl lcitis usd. Th smll th K, th g th sistnc ncund by fluid. Lking t fsh, th g lu f K is. duing th fzing pid nd. duing th pn pid. As th lu is smll in in, this indics tht fluid mts g sistnc in in thn in summ. This is ssumd t b du t fictinl sistnc f ic shts, hich is thught t duc th lcity f fsh. Lking t slt, th g lu f K is -. duing bth th fzing nd pn pids, hich mns tht slt mts th sm sistnc ith ithut ic shts. Fl s f fsh nd slt Slt intusin cuss bth fsh (i ) nd slt (tid ) t ln dnstmd nd upstmd, nd t h fl s tht chng ith tim. T cmp th fl f i nd tid duing th ic-cd pid nd pn pid, fls put int fu cgis bsd n th bsd fl s nd slinity. Fl s nd dictins (upfl, dnfl) f i nd tidl dmind. Bhi f fl s Figu shs th cmbind fl, th fl f i nd th fl f tid, s ll s th ll t th bstin css sctin. Psiti (+) mns dnstmd fl; ngti (-) mns upstmd fl. Th upp gph shs dt cllcd duing th fzing pid; th l gph shs dt cllcd duing th pn pid. Th fl f i is indicd by dts; th fl f tid is indicd by squs. Th hizntl xis psnts ds. Th lft-hnd ticl xis psnts ll, ngti fl f i, nd psiti nd ngti fl f tid. Th ight-hnd ticl xis psnts th cmbind fl nd psiti fl f i. Bsd n this, th gphs ll us th flling but th fl s. --

8 Pcdings h th th IAHR Inntinl Sympsium n Ic (6) ) hn th ll is high, slt intuds (th tid fl is ngti) nd tcts i upstmd (th i fl ls bcms ngti). This cuss th ll fl lcity f th stm t dcs, nd th cmbind fl t dcs. ) As th ll flls, psiti fls f i nd tid (mining in th i chnnl) ccu, lling th tht hs bn tind upstm by slt intusin t fl dnstm ll t nc, hich cuss th cmbind fl t incs. Th nlysis hs shn tht ths bhis cmmnly ccu in bth th fzing nd pn pids. CONCLUSIONS Similitis nd diffncs btn fzing nd pn pids idntifid bsd n fild bstins nd nlyss. Cmmn t bth pids ltinship (-), 6 (-) ), i (+ f tid f l F l, l F l - - (-), 6 (-) ), i (+ f tid f l F l, l F l - - ll Fl f i (-) s Fl f tid(+) s Fl f tid(-) s D Cmbind fl s Fl f i (+) s Dnstmd (+) ) Fzing pid (in) ll Fl f i (-) s Fl f tid(+) s Fl f tid(-) s D ) (+, fl d i in f b m C - l F Cmbind fl s Fl f i (+) s Dnstmd (+) ) (+, fl d i in f b m C - l F b) Opn pid (summ) Figu Fl s f i nd tid btn tidl nd i lls tht plts s clckis incs-dcs cycl, nd tid-ld chng in th stm cnlin psitin. Th dictin f pimy fl diffs significntly btn th ic-cd nd pn- pids, th disppnc f hlicl fl duing th fzing pid, nd dcs in fl lcity f fsh in th slt intusin phs f th fzing pid du t fictinl sistnc f ic shts. Diiding th ttl fl f n bstin css-sctin f th i int fu fls nbld clifictin f th cmplx phnmn f slt intusin. ACKNOLEDGEMENTS uld lik t thnk th Abshii Dptmnt f Dlpmnt nd Cnstuctin f th Hkkid Dlpmnt Buu f piding us ith mils nd infmtin, nd Fukud Hydlgic Cn C., Ltd. f mking msumnts nd ld ffts. REFERENCE Kichi YAMAMOTO, Aki TAKAHASHI, nd tu FUKAYA Actul St f Slin Intusin nd Its Mixing Chcistics in Tidl Ri, Achid dcumnt f th Public ks Rsch Institu, N., pp. nd -,. --