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1 51
Tl 669
R.V.Dcnchenko
Draft Trans la t ion 669
March 1978
CONDITIONS FOR
ICE JAM FORMATIO~~IN TAIL WATERS
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ARCTIC ENVIRONi.:EN TAL INFORMATI ON
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707 A STREET
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CORPSOF ENGINEERS.U.s.ARMY
COLD REGIONS RESEARCH AND Er.G1NEERI NG LABOPATORV
H...NOvEn.NEW HAMPSHIRE
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REPORT D~ENTATION PAGE RE AD I:olSTR UCTtO~S
DE FORE Cm lP LE TnfG FO ~.1
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I .P I:It ~O ""I N G OACiA'"ZArtO"......1:"10 AOORIIi
U.S.Army Cold Regions Research and
Engineer ing Labor3to~y
Hanover .New Ham pshi re
It.CO ..T ltO L LI ..G G~~ICE ..loME ....0 AOOltESS
lIe.OECLASSI~ICATIO'"oo ...GIIIAOI ..O
ICH&DULE
II.DtS TAlaUTID"S TATE..I:..T fe '""••'I_ 'J
Approved f or publ ic r elease ;d i stribution u nl imi t ed.
IL I U~~LI:IOVOTAltT "OTEs
ICE JAMS
ICE EDGE
ANALYSIS (MArHE::1ATICS)
GENERATIONS
ICEBREAKl1P
TAILW,\TERS
HYDROELECTRIC l'O\otn
JO.A.",Ar:T~H __,_,tr ~Neca_J
~On the basis of studies on the dyn ica of the ~ce cover edge the following
peculiariti s were f ound in the foronation of j~in t ailwaters.Formation
of ice jams in ta ilwatera is a consequence of the dynamic destruction and
separation o f the edge with increased discharges.The process of dynamic
d~struction of the edge evolves by the formation of cracks along the shore,
debacles.and hummocking on the se~tion within which during discharges the
size of fluctuation in the water level is 3-.~t1."1\ftS greater than the thicknesS'!-
DO •~=-JI 1m ~,"oe.0"•'tOw "'S ~IIT&
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Unclassified
I ' CUIt'T T Cl.ASI,I'ICA T 'ON 01'TNIS ~AOIE(Wlo _D...b,wM)
of ice on the edge during its formation.Ja s are formed at the jo inting o f
the int ct i ce c over ond t~~shattered field under the inf l uence of t he f o r c e.
of the flow and pressure of the ice field whi ch exceeds the resistance o f th
ice.!he amount of the greatest jMm lev I Is in direct dependence on the
amount of maximum water consumption in the peri~d of j formation.An i n-
crease i n discharges during the for=ation of ice jams promotes the increase
in capacity of the jam,and 3S a cons~quence a reduction in the winter co ~f
ficients occurs.Regulation of the CES routine depending on the con~itions
for i ce cover ~dge formation on the s ect ion within the diurnal lag t~e is ~
nece s sary condition fo r the movement o f the edge in the tailwater without J a~
f o roation.f-.
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I llS lMI ....)(
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~L~•.•·'m 0I~i ;;:wr...____...
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l :Jllrsl :I_,,,...m _
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DRAFT TRANSU\TIO~669r.:
'--""~~CLISII TITLE:CO~OITIOliS .t6R ICE
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rOR.'lATlON 'TAlLUATERS
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FOREtCli rrns.
AlmIOR:
SOURCE :
CRREL BI3LIOG I\A~l\'
ACCESSIOlln:c lID.:
USI.OVrl.\05R.\zOVA:UlA Z.\TOltOV L'DA V :HZ~IXll B'EFAlQ\
R.V. Donchenko
Leningr~d.Gosud~rstve~nyi gidrologlcheskii institut.
Trudy,1973,Vol.227,p,31-43.
..
30 -:),447
/
Translated by U.S.Joint Publications Research Service for U.S.Army Cold
Regions Research and Engineering ~bor~tory,1978,17p.
!DTlCE
The contents of thi!publication have been translated as pres6nted in the
original text.No attempt has been aade to verify the accuracy of any
statement contained herein.This translation is published with a min1=um
of copy editing and graphics preparation in order to expedite :he dissemination
of inforaation.Requests for additional copies of this docuaent .hould be
addre ••ed to the Defen.e Cocuaentation Center,Cameron Station,Ale~andria,
Virginia 22314•
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CCSl:Ukil ST\'C::::lIl Cr:ROLCCICHESiG"!msrrrrr.'l'!U':L:Y in Rus s i an ve;227.~975
rP 3:-:'5
~~~tic le by R.'I.~onc~e~~~J
L'l'ext ~T~e s ect 1en c~CES ta ~:water w~ic~is l oc~t ~in t~e pu ls1t icn :one
c f the ed€e c f t~e ic~ccver is c~aracte~i:ed ~y ~~~st1b:e lce ratt ~~n.
::r.:ier the infl :Jence ~f ~:'i r,,;,r.,.l a..'l:1 w'!ei<::r regw.aticn cf t~"e GES dt=lr-,!>,
t he wlnt~l a c har~e 1n the i ce phenomena occurs cn t his sectlon--alte~naticn
of freeze-u p wlth i c ~drlft a..~~ovir~sludge .Here as a ccnso1~nce of
~luctuatlon i n the water l evel.~'l:1 an lncrease In :ongl t udi nal lnclinations
a."ld cur~ent velocities in dls cn arO(es favorable ccru:!lti':lns are created beth
for t ~e .fo~atlon o f 1ce ~~s d ~i ng tn'll generation o f t he lce cover.and
f or t~.e f onation of ice ':atlS durlng lts destructlon .The cn:.altlons for
t he fC:::lat lon of 1 c~j a::r hencrter.a !'lave been ~evlous:y exan 1r.e:i 3ll<:!
rubl ~5h ed ir.~ork3 L4 ,5~.This article pr~sents questions c f th~~estruct~on
o!tl:e lce c o·ter and t he forllatlon o f lce j u s In t he CES tallwaters .
S tudy o f the laws go vernlng tr.e fO~:Ilatl'J n of lce ;a::s 111 ta llwat~rs was ~
on research of the cor~lt1~ns for stab1l1:al.lon.c reak1llg and sh1ftlr~o f
the l ce cover ed;e d e?8ndlng cn the CES r e ...t ine ,and the cl'.ar.ge 1r.t ~e~:'la1
a..'l:1 h ydra ullc c har ~cter lstic s a lor.g the le ~-th of the ta11~ater.
For thls pur.ose the ~ollowlng were selected as the subjects of research.
tailwaters cf t he VolGa CES !JIlenl 22nd CFSU Congress and the <lratsk ;;ES
1:Ienl 50th A n.~l"/e rs arJ of the Creat Cct ober .In ~dltion.Clode l studl'!s
were :aade of the lDechanls.-1nvolved ln ice .lUI foraation.
Condltlons for Stabl l1zatlon of Ice Cover ~e
The pos l t lon of t~e ice cover edge in the t a llvat er 15 deten1ned by the
heat f lows en tering t he tailwater.the heat emission frOID t he water sur~ace.
and the hydraulic pattern 011 the section of its shift.Stabllization of
the edge occurs on the tailwater section where the heat flow is coapletely
ex;l8nded far heat elllission frca the water surface.and hydrodynamic stabllity
o!tl".e lce cO'/er edge occurs.The5e conditions can be presented in the
-1-
._'
following forllll
Qr~/-Sl.ofJ.(I)
f'r-I';H -V~I II ,,1(I-Ih)(1- ";').(2)
According to L9J .equation (Z)reaches the C!ax ~"I t.::
(3)
';'
wher9 ~--consumpticn of waterl t--tempArature of water discharg9d into
tailwaterl S--heat lesses fro~water surfacel Z O --d is t ~~ce of line of zero
isotherc to dam;B--width of river l Fr--Froude number;v ar~H--velocit7 of
current and depth above edger ••••r --density of water and ~ce;£--pcrosit:r
of ice floe acc~ulations;h--thickness of ice.
As a consequence of the continuous changes in ceteorolegical conditions.as
well as cf a diurnal and weekly CES regulation a shift OCCl:rS in the edge
of the ice cover along the length of the tallwater.Thus,according to t!:e
data of studies on the ice pattern of the Volga GES heni 22nd C?SU CO~9SS.
there WM an almost diurnal change in its position in the winter of 196;-196':'.
Here the edge approached clese to the dam nine times L~the ~e n~ber of
times withdrew frc~it to a distance of 6O-eo kin.The ~ain reason for the
return Iilovelll8nts of the edge was the sharp change in lIleteorological
conditions.and accordi~ly,a decrease in heat losses fro:200 to 100 call
(clll:>.day ).In a number of cases simultaneous reduction in heat losses
frOIt seO to 200 cal/(ecll.day!and increaso in the lIlean dil:rnal consumptie!'oS
of water f~olll )000 to 7000 II /s occurred.
According to the data of lIlany years of observations,the stablli::ation
section is 4 kill fron the dam in a cold winter.and 64 Iu:in a war lll ..inter .
Dur~.g cr.e w~nter t C9 position of the edge ch3Jlges within lO -}:)CI first
it approaches the daa by 8-28 0.then it withdraws froll it by 16-58 kin
(19C2-63.196;-64,1964-65.1967-68).
In the tailwater of the Bratsk CBS for conditions of midwinter (1C;61-62}ar.d
with :.later cOlh.JI:lption of 2000 l:l.~/M the least distance of the edge frclI
the Cal!>.was 15 :tJll.In warm winters the edge was at a distance of 40-90 r.:l
ceper.djng on the amount of d1acharge and the temperature of water enterir.g
the tailwater .
The edge of the ice cover cOllpletes cOllplex osclll1ting 1Il0veunts depeOOir.g
011 the change in ..teorol05ical .and.hydrological conditions I however,its
..an position for a lengthy t1Jle interval coincides with the section of
stabH1zation whi c h is lOCAted in direct p:-o::iJlity to the line of :r.ero
-2-
»:",!
•
.-"r --.".~
te..perat.ures.Therefore an evu:ation of t.he ..an posltion of st.&bl~lzation
of t.he lce cuver eqe for t.he subject.under Et.udy can be lII&de by usl~~he
calculated depend~nc1es fer the posltlon ef the 11ne of :ero te=peratures
aler-4 tt'.e length of the tailllater on the heat l esse s ,tel'lperature ar.:l.con-
s~rt~on ef vat~~entering froa the reservoir 1nto the ta11llater,
(4)
./
.erk L~_presents the ~nd~cated de~endence for the ta1~lI~~er of the Vo~a
C::5 1r.eni 22nd.C:SI:Congress.The e:l:'e;l:at~on has used the extrelt8 valces
of Q (z"C-e,5:o :R~/s )and 1.(O.}·v .l~)lIMch :uve been obsen'~d.alr.g tr.e
!'ree:~r.£of U:e ta1:'vater of t!".e Volga Gr;:;,correspor.d1r..<;;to 99 ar,c l%
f:e~ueney.Cale ~:atlens ~;r heat losses lIere Dade accer:~~~to the Method
cf he3."bala::ce.For t ~.e val~s ;j a::d 1.1cce;:t~abo ',e lI~th !".e~t losses
above ieee cal,'(c::2'daYI tt.e lir.e of :-:-c teC!perat·.:res ~s :ocat~.i at a
distar.ce not :'lore tha.'l 1;%:froC!the d3l'l.iilth heat lesses ~O-JC;V call
(c:a 2 .cay)11.10 se rarated froJ:the du at :1 distance to tOe 1-....
Fe:the st.able ;esltlcn of the ~:e ecver edge 11.~s necessary to alse
!~lfll~t!".e secor4 e~r.:l.~tlon.1.e.,the realstL'lee cf the lc~cover ~ge to
~~~action of externa:forces.
Fr:=an analysls ef the :iat~frel'l 1~cover f:~atton 1::ta~lllaters ~t
fo:':evs tr.at the ed.:e 1s fixed na1n~:;froD the layer of s~,nge,the th1ckness
of vh1ch ls detert .ned by the condltlons of ~ts fr~z1r~together and by
the hydrau:!.1c eha;.:~"ter~stlcs of ~he sect lor.of ~ee foreat10n.In the
ta~:vater of the Vo :~a Cr;:;1=en1 22r.:l.C:~~Cor~ress the layer of sludle
0 .;=lI~th alr te~~e.,ture -lO·C free:es 1n 5 days.iilth ceJ:;:~ete l~ee :~ng
the s:uige lee bs teL~.'On.rJ res1stance to sr.ea:lr.g equal to J.7 ~/e:2.
Havlr~accept~the ;:'ro.:.~e nlll!lber as the crlterion for the I1Y1!=c:dy:wo.1e
stabl~lty of the lee cove=~!e ene car.deter~1ne tt'.e d1sta:.ee along the
le~th of the vater to thCf edge de~end1ng en the thickness cf lce.Tl:e
~!".a:actarlstie val~s for the lnlt\&l thlckr.ess of ~ce ~hicl:for:s the ice
~OV9r ~~e 1~the tal:lI~ters of tl:e 3ratsk and Vol~a C~are glven 1n tab:es
:ar..:i 2.I:epen:i!.r.;on ~he-:.rate:cOI :s1.:~t~~n ar~heat :vsses 1n t.he peri=:-:
of freezir~the lr.itlal thickness of the lee fl~ctuates ~lthln ~4-)3 C2 on
th,Ar~ara a.'ld 22-58 e:on tr.e '/o~a :tlver.
Under tl:e lnfl~nce cf ~~iurna:and ....kly resulatlon of flov 1n the t~l
vater a cl'.ar~occurs in the hydraulic characterlst1cs vh1eh resl<s ln a
~isru~tlcn ln the ~ui11bri~between the forces ~1~~act on tt'.e ice cover.
Shup oscillatlons 1:1 tt..vater level 1n tt'..f1:st days 0:freeze-up lead
te lts destruct~cr..
The effect.of Laves of :i1scharps on the stability of the r..ge position 15
deterll1nerl by the ..ount and ciuration of the d18cha:se.For each tallvater
one can establish t.he :one of lnfl..nce of -iischarses on the stabllit.y of
the lee co,~r edse ~'lder preset.:eteorolo~lca:cond1tlons.As ls knovn,on
rlvers v1th relative ly S6~'1 dlscharlles as cospared to t.he river bed capac1ty
-)-
••#•
,:.....••.·1
-
Table 1 .Hydrometeorological C~nd1t10 ns f~r Stab1l1:at10n o~~ce Cever
Edge 1n !allvater of8ratsk CES
(,)!\,})I (;.r-.~tS );"J...·.IlI ".,.·I .,;•...-....,......-..I Ih ,n t tl .,,,•3__••(T_.,.,,1_'Jr'I ,....,..............,......I _~w••'.;I ....1"4'..•••\8••••
\....,.....r. J,..........t M I.1 ""..;-.......,
.~I '..
\......"._....'C I ..
I
:~"'Z ·61 ~S I _I ll JI.,ill O .~1I ••1.~
I "f>l ·~'\.1 -::..l ~J.,I ',b n.h;
11 t\.;(Ai /j.~I -~~"Ifl n.'0 .11
1'titi--6i ..,-.:'I Z.Oi '0 .'Il .Z~
19(,:'-b."I I.<l I -::6 .1:'1'"1.1
'
O.:.!,
!!,;q fi"I ;~!-·2..~:".)1.1 fl.:':'"
I ~o(j:l it).J I -I ~::,.,.)O: J
f,:......
!
3·
.1nter pericd .j~~
D1 st~~ce of s ect10n of
s t ab1l 1zat ion cf r.1ge froc
~a;n ,km
J.~t"l!l~ratu:e .~C
,;,;..
5·
6.
'';a t e ~cons~r~~C::.0 .1,'5
,eloc~ty c:C~~~r.t :e !:=~
l!d ge ,r:./S
~n l~1al th1ck~e5S :!i:e .:
Table 2 .HJirometeo~010b1cal C or~1ticn s o f Stabi11:a t~o n of r~:ov~~
Edge in Tallvater of Vol;j;a GE S 1Jl:en i 22nd C:SU Cor.g ~4ItSs
(,.\(X)\r"",<~1 ('II I .G)i"\loi"h"'_I !,.!P ....... .';:.:;"......~..I Ill...t_."
•100·........"...,.,.(f ........."'...i _.,..."...~,,......-.
,,-.....I.'.1 Il:~"".'",",,"p .••
.."r ....-.\"".....,~.."'1:I ..
,
I
1!V'"til (>l I.,'...;,.,II.:"n .:....:.11.....'
I ~"JI 1 ~2 r;\-.l .:!I~;~I II .~I I .~'u,;;
1 ~"i:?,;'1 19 -1 ;.2 7 ~..~'I'.'·,,fl .:!.",It .".,
H.~.l~IIj.J h '12 --:."0.11 "'I :",
1!lfM.r~.:.'1)-I~.Z l illl n.:,'j ,11 .,"1
l%'j·(i6 ~7 _';.11 _11iI \I '.~I I t.U..1!)Iifi-h;I~··n .'hl'll n.:"l I tI ....;
1~·61 17 Ir.•.\1lJ.·..fl .;:t
I
....~
19I>'I·&J ~..~n .h ifdJ 11."-)",:\.)
1!lt1)··70 19 -I~.G ;"..II ...,tI .;".'"
1970·71 19 -16.1 ~'dl .,.~U.S
ICe Y I 1.Winter period.year 4.'later c OflS\.lIIlptlon,=~/s
2 .Distance of sec tlon of 5·Veloc ity of Cl.:rre nt be :-ore
stab ll1zation of ed ge froa qe,m/s
du ,b 6.Initial t hickne ss of i ce ,:!.,Air temperature ,OC".
,...
••1 -4-
•.I --_....-
;;.......-.'..',
r -:--......
!
"
t.he vaves of d l scharge are s pread fairly qulckly.and conversely.with
relatively large dlschargell the VaYltll are spread oYltr a gnat IHst.ance.I n
t.he p:-esence of an lce cover t.he coefflclent.of s;:read for waves of :Hscha:ge
1s ~n ere ~s~as a con5&qUdnce of t.he ~e1ght.en~n;of t.otal roqghness.
E3~c1a~~y extenslve spreaelng of dlscharge wa~es is obser/ed on t.he 1~~1C
sect.iens ef t.he t.allwat.e~.
~!:~ct.uatlcn in the wat.er level also occ~s corres?On~1r~ly t.o the c~~e
~r.wat.er e o r.s ~Ft ~ or.:n the tal1vaters.In winter t.he slz8 of f~uctuat~ens
in water l e vel d l ~e c t:y at the dam of the ta~lvater ~eac~~s 2-3 =~t ao l e ;).
~s one goes farther dc wn st re:u:t r.ere is ""~ed uctlen in t.he aJlIou::t of
!:uet~t.lon i n t he ~e~e~accordlng to the ~xponentla~lav ~2~1
(,il
where ~,~A ~,--respectl~ely the size of fluctuatlon In water lev~l d~ectly
~~ow t !ie ,~::3 i!'.::at a :l.istance L k:l frem t he GZS,T--d~at~on of dlscharge.
h .;--l ~t e n s i t y c oefflclent f e~s~ead of waves of dlscharge dependlng on
t he =cr ~o~c g ~c al st.ruct-xe 0:the ~l~er ~d and on the slope.
T!.ble 3.C~eatest S ize of Fluctuat.ion ln Level ln Tubaters of CZS ln \l inter
:"':c.•k cv sk aya
"f o ~...1=:enl V.-
:.snin
r:o "/csi b ~r sk
:1~:!1~~-5v1::u:a:/a
Slze of
fluctuation
ln level,em
1)0
2:))
2GO
leO
CES
Volga ~nl 22."l:!
C?SU Co~ess
Gor'kovskaya
Brat.sk
Size or
fluctuatlon
in level.a
zeo
160
ZOO
.......
~ccc~d~~to ~"e data of research,tr~l1=lts of dally regulation ln wlnter
::r ~~e ~~13 n cJ ~s k CES ::~a c h 160 ke .for ~~e V~lga ~en1 V. T.:an1n--
:;C k~.fc~the 'Iolga l~enl 22nd crsu Congress--:OO km.for the Nlzhne-
;;v~slo:aya--60 ka and fe T the Ivan'ko'/skaya--"O k:.Analysls of the obser-
"/at ion ~ter~a ls e stablished that the effect of dlsch3%'ge Va "/es on t.he
stabll1ty of the lce cover edge occurs on the sectlon of water near the dam
vltr.~n the diurnal lag tiDe.
::eforltat,lons al'.d :lestruction of t he Ice Cover E:dge
The develo~ent of the process of dynaolc destructl~n of the lee cover edge
occurs in the follcving seq~ncel
formatlon of coaatal cracksl
debac:es and h'JI'laockingl
se Faratlon of the edge.
-5-
-;...!...:..:~i
,
,-I'__
~/-..,.
j '
"I
\
-,
!n the passage of dlscharge WllveS t he f:':.:c~aticr.a ln wuer :e·".!.&r.:i !.::cr ..ur-
ve!.oclty ra ~~e rn res ult i n ti:,&P~&Z&nce of cracks &C4 &!.c sa ir.~i:.
c o ntlnu l~y o f t he ~ce co ve r..~t h i ~scha:g8 va~s t he ~e s t r ~t ~:r.c ~t ~e
ftd~e o cc ~s e n t ~~c:est c !~~~VaV4 v r.~ch ~:es ~~.r ~~e ~c e c :ver ..~
b uck11ng t !':e i ce co ver =eac~e s cr1t1cal ::er:'ect :,c,r..s ar.:l :rea;cs.
The eX lst~ng =e thods c r ca :c u la~:'o r..~&~ed e n ~h.t t~cr 1 n ~.:.st ~c ~t ]l:~
h j~r c~~ch ar.~cs .~ake i t ?Css :'b1e t o ~~t e=~~~~t~~1r.~~.~c ~~::'t :'c ~:=~!~
:'n vat~r :eve ::'n _hi c~coa ~La:c:~ck~are :c ~=e ~.
By tak ~~~:'r.t c a ccc~t t~at ~t ~r.~~~~e ~h.:'c~_e :v~r :'s ~~~a::1 :~~~~c ~.~
to t he s nczes ,t ~.l!!orn~l a c!:..:•.::~=:-.a.."':O ·1 .-:..C ~"=-'"..sa-:.t ~:,;r.~:..~e ~:".'"
cr ~tlc al ~i se ~r..ater :~v ~:
II.~:H.'i ..'-J';,:-.
wt~re H"--h~:'~ht ~!~:'se in :eve l.C~l c·-te~rora:y ~~~~~~str~s3.~g !e=~1
h --thickness of :'ce.c:::2--~Gd u l '.1S ,J ~.'!13sl~c i~y o f ice;~"'I 1:".:i x - - f ~:t.~c~s
o!relaxa~icn d ete~~i r.9d by C1 ~C U :3~~~g=~~h.
For cases o!s o-cal l~c hir~ed attac~~~r.t of t h~i ce c cver ~o ~r.e ~hc r~s ~~e
nu:erl c al coe f !lc :'e ~t o!c i:c ~~a~ed f o r=~a (6)~$~aken as ~aal ~o :?~.
In ca~cu:at1ng the r!.se l n :evel .h~ch e llclts thd a ~.earan:e o f c~acks i::
the ice co~er i t is raeces sa:y ~c take ~nto co~siderat1on ~~e ~e pe ~en ~o ~
;x en thu l ntens!.ty of d~schar~e.and cf £ar4 C o n the &i ~te=per&~~,
T ab::'e 1.0 rrese nts t l".e c alc ul atei Vll\;8';for tl".e c ~ltlc al ~lse !.::water
l ev el f er two vlIiar.ts of a.t.tacru:ent cf t he 1~c o·''':-to the S :-.0:85 :.:':1: 8=
d ~fe r ent =etecro log~ca~condltlons ,
:t !ol:'o.s !rca table 4 t hat ~n t he !1:s~var !.a::t w!.~h s::all t ~lck::ess c !
the lee cover (i o cm)f or::ation cf coasta~cracks s hould be e7.~cteC w!.~l".
r ~ses ln the le~el 12 -26 CD de.e nd ~r~on t he air te:ll~~ature,whl ld wit h
g:eat t hlcknesses (JO -.50 ca)2;-;1 ar.d J2-6=>ca ~espectlv":':r.:o~t l".e
s ecor.d var~ant the c crre s por.d~r~ca:culated v al ues !er ~he :!.se ln l eve::'
are two t1=es SlIIaller.
Com parlson of t he calculated arod observatlon data fer t~e tail:late:s cf the
V o ~a 1JDeni 22:1d CPS.!Co~ess ,Gor'kovskaya,ilyblnsk GES ar.d others reveals
the satisfactory agr~..men~of the calculated and l:euured vall.:8S,
Thus ,accor:i!.n.g to the data of observation ln the talbater of the Volga
GES 1Jlenl 22nd CFSU Congress :.n the wlnter of 1971-1972 with the lee cover
edge located ::l2 km from the GES the fermatlon of cracks along the shore
occurred.:11th a rlse ln \later level 28-)2 ca (calc.aated value for rise !.n
level 24 ee},In the tail\later of the Ryblosk GES \lith h-16 ca formation
of cracks along the shore \las obser/ed.as a result of a rlse 10 water level
by JO-)2 Clll (calculated--)6 es},
-6-
"-....---_...._...-:.....\
7,::e~.~a lc ~:a~e~'al ues for Cr1~1cal Rise in ~ater Level (cm )
(,L)........,~..-...I I "....:"••
',••••••J ...
l;)lU~I N"I '"''''......"....101 ·'"....,..I ~('t t""'''''
till M ",'•••:
---'
;.."~b -j 11
";Ii ..i '
:'...,Z!..I:1-,'~l
•I '·1 II '~6
'.'.1 i I ·1"1
::~:::
:~.~~:"'.e55 ~~~::e .c:
:~~:~p:e~~~t~~~~;e~t of lee to sho~es
~~~~~1~~~C~~4~t =!~ce to shor~s
'•.;..~:·."~;CI!=~t~~.;:
....:!.~~·-c ':.~~...t:"'.e -.,C'~lr.~f :r 1 t -:'ac!"'.::er.t o!t.t".e ice CO"/er to the shcres it
~~~~s s a:y ~~c :~~~~e=':.~e t~e wh~=h t~~e~e was located at the g1ven
:~':~~::!'.a.:..:~:-.'!=:e t ~:r"::~~~c 1:cor....:.~-:.iol:s c f t:-.o exarl1.ne<i ;erlod L'1 order
~.~1f.e ~~t ~a :c:~t t r.e e~:ect :~t he ~ce !reeZ1r.~toaether with the shores
1.t":a.t t=-.<8 sa..:e ~:'::'e g ~"I~;::eferli!nce to croe c!tte ca:cu~at6d varla."1ts.The time::=t~~~=~~~~~t~~t~e ::f t r.e s l~e cover can ~cCuputed by the
h:,til
'''':''.'!:'l!'".•0.--s?"c:'~!.:~e~~t :!sl'..dge ~ice t A.--coef!1clen~of heat-"
c ~r~~c~~~~~J :f ~cet t--ta~:~ra~~e of s:~~e scrfac~;h--thlck~ess of ice;
=,,--:'a~~~to :-.ea.t.of :'ce :oz __"1on.
:~I ~~e~~o ..'/a: ua te t~.e e~~ect 0 :'d1schar.::e vaves on the destruction o~
t~1~eever ~~:lu:1:o.g 1ts P&»""~cn var1cus sections cf the tallwater
~r=e :~~~..ar:r c1:cU:at.:'cr:show-:!.he ::ade of tne aDo..:nt 0:rise !,n water
:'!v~::" rer..:1 :':-""3 en tor-A s~:e 1I'.d d .:rat1or:of ~:'sct-.arge waves,and then,by
'"ol:~:o~th"ca:c:::at&.1 values ~or t he lIla.X1J::u:l rise.the cone of L'It'luence
o~~lschar!"vaves ~n :lestr::ct1on ~f the ~ce cover can be determined.
Tab le 5 g~'/es the val.:ea for f:uct.:':&t1on 1:1 :evels alo"ll:tne length of the
GES ~a~lvaters.!rca vh~~~it can tJ conc:~ed t~~t the effect of d1sc~4rge
on the stab111tj'o~the ecge !.s w1th!.n ~·e)J-J:l of the CES du.T!lua.tor
tt-.e tallvater or the VO~1 GES 1:Ien1 U:ld C::SU COng%8ss with great discharges.
-7-
and co:respondir~ly with groat fl~ctuatio~s in t he lAve l alcng t ~8 ~er~th
of the tallwater &3 well.the stability of the edge 1s ci~srupte<:!d~ir~~ts
movement on the section or tailwater up to 6C km.
As indicated.the ror=ation of cracks alor~t~e shere is th~first s t .~e
in the destruction of the ice cover.After th~~rc r~atlon t~e ice r.~'ler
will rlse together with the wa~er level and operate ~r.er ~o aj as a s~~i
1nfinlte slab ::ith f1catl.~e t-ge.tir.der the ~~!~:.:er".e ~:'t i",e ':r ~;~r",
force of t he f lo".as wel l as the wind !o ~.~r~p ar~~re~~:jr~~J ~r.'at ~r
surface,a loss occur~in t~e contlnul~J of tr.e ~e~co~e ~.~.~.I :r~~~~~~r
of the ice fields into ir.cl~·/ldual ice !l c...s ar.:!t~.elr :-~-~~CCf:~q.!:'"....-_~:c;:~r.£
ls not vbserved in the breakup,but on ~j se ;:arat~en or tct h ;::It;,.::-..,r.~~,
is evldent that this br"aku;:"'as a re"u ~t c r :er:Hr~~'.r'!s s ::h~:r.:cc "-'"r e:
in the lce field from the passage of a wave ~f :r~..f i ~~c ~ar ~e .r.'~:c ~f:~~:
occurs as a result o~a loss in the stacl1~tJ of ~r.:~7 ~=~1 :c ~~::e ~
during compresslon.
~en discharge ~a~es ~ass or.sact10ns of th~t al 1 ~a~e~~h~~~=~~e s .-~~:~:
level exceed the thickness of the lee eever ,fo llo 'o1"~tr.o!f er :,,,",:v:::::f
coastal cracks flota~1cn ar~losses 1~cor.t:n~:tJ ~f t~d :c~~C~~=~c c ~.
Intensive deformations J ,'the i ce cover take place ;:alnlj w~t h ...3!':2:;:
·rise in the level ,att.d c~ten :Il!s u~t 1n •..he dt!bac ~~c :"t.r.e :-!.O/,,::l.;~=~~~sz :..:~
in the edge of the ice cover edge de~nstre&~.In t !':ls ca~e d~s~r ~e~~e~:~
the ice cov"r takes ,lace by breakup o!the f ~e l:w~th cros~=r~c~.3 .!':~c~
develop when the height o!rise in water le'le1 ~s r-'!ater ~han '.:-.9 :-.e~~~t ;.:'
aax1mum def~ect1on.
The aJ:ou:,t 0:'ber.d1t'.g coment with the r.ax~u:::-.e1.;ht.o f ::o!:':~c ~~,,::c:!..":':..
deter~ined by the !or~~ia cbtained after lntegra~1or.~!t ~~:i ~~~~~n~~a:
~quation f~r ~he curved axls of ice cover with reg~:!:r certa~n ~I ~;:~
!lcat1ons L11 ...:
I ·~I
whGre f --=a.x~'':::defle<',~on I h--th1cy.ness of ~ce ecver ,
lI'.atCC
The appt:uance of c::acks should be expected i!
('I)
where G'...--res1stance of ice to ber.d1..'\g.
Having used the ~ata of eb~er/at~ons on the ~ntensit7 o!::~se ~n water
level during dlsc!la::ges one can det8rl:ljr.e t ~~thickness of t.he ice eever at
which its destruct.ion occur:!!depending on t.he "ate::cor.sUl:lption.!!lus .f or
-8-
,J
...,..,
"
·.'
....-.--.
Tablo 5.S,rllad of Wavee of Discharge 1n Tall'lat.ors l4]
_._------ -
---~l -li~In o •
r»C .....)..
,;."
CES
DuratIon of dIscharge,h
Outlays of discharge,m3/s
S1ze of fluct.uat.1ons 1n level 1n
t.allwat.er
Slze of fluctuat.1o ns 1n levol In
percont.age8 of maxlmua alone length
of tailwatftr.km
.
~'j
,i
f\'I,',.,-,
'\
"I.....
,.
\.
q..J11.;aIl".IUM:"~."•
ll!"1,~n""It('..·u."""UU.l..,·~.I.
H N .U.II J1('III.·
na ...."
~lI\"\lO;:I..."
l"'ll h'.II,"C.nl"·";··
",11;"'·'10.3.
11\1.XXII U,('I,Uxucc
I
~
I
3.7
3 .0
II
13
~
~
1.
2.
).
4.
5.
7 .0 ~'K 1 .5 ·11I,,:.!1.7M
!):,,o ~1 4\1 ".'J 3 .31
If,'I&1 i:-.....I.:i ~.U I'''.1 :!:..••~.I 1,:17
II IUIlU 1.7U
3.".uu II.",(XI I,I.i
~18 II U ,~••U.!IO n.M "."\".""....\"."II ,..)11 ,:12 ".~I I ",I r.I","'1 U,Il
11 >'1 o.~1ti 11,,,-1 II,R7 11,81 U,7;,0,'.1 0.1;'O.!'II II.U 11 .,11 II,:!'J u .17
2W o.CJO 1I,1ll)U.65 U.M o .~~0.37 o ,3U U.:lU u.1J &I,b'\
12:.0 'I U,!.l5 0 .87 0 ,76 .'II .~I D.Z'JI 10 ,..,1 0 ,118
6.Ivan 'kovskaya
7.Kracnoyarskaya
8.Volga ll1enl V.I.Lenln
9.Kamskaya
10.NlzhllO -Svlrshya
11.Volga ll1enl 22nd CPSU Congl'eS8
eXUlple,in t.he tallw'1ter of the Volga Ct:S iHni 22nd C?SU COll@;rass then
the ~is 60 ka below the CES daa destruct.ion or the ice coyer edge aust
occur wit.h cons~pticns ~f wat.er greater than 6000 .~/s arA thickr~ss of
ice at tho edge l ess t.han )5 em.The ro~ist.ance of ice to bending in th&se
calculations is taken,accor~1ng to l6],as r;",-40T/a~.
Under t.he influence of water flow L~wind on t.he section of breakUp of the
ice fields debacles occur and processes of h~ocking and coopressinn of ice
ceYelop.Reformation ef t.he ice coyer edge essentially takes place 1U9 ~o
t.he dj'n3:lic increase in ~hickness of ice l'.Ccordir-f;to the hydIaul1c charac-
teristics of t.he section and the meteorolOgical conditiens.Debacles
ce=lnat.e which result.in the shift.ing 0:t.he ice coyer great distances.
r.:lweyer wl~h sharp changes in tho anolOllt of discharge powerful debacles occ:.::r
which eneeepass sections to 20 km. The duration of such debacles reaches
2-)h.
The sizes of the debacles depend on the correlat.ion of forces which pro.ote
ani preven~ice movement.i.e •• on the aaount of active arA reactive force3
L1,61.n.e active include forces of water and a1r friction on the lower
and uiiper surfaces of the ice coyer and on the >l8ight component.of ice in
t.he d1rect10n of the flow.while the reactive include forces cf resistance
by the shores and edge of intact ice C:lver.
The t.ot.al amount.of hydro-and &9rodyn~~ic load on the ice fiel~s as a
result of friction of a1r and water currents on the borders wat.er-ice and
.a1r-ice can be presented in the following'forllli
where BL1 --width and length of the ice field.ml v and v--respectively the
Yelvcity'of current and Wind,m/sl a1 and a2--coefficients of hydro-and
aerodynaaic loads.
rt.is necessary to not.o that the act.1on of Wind 1s grea~est if its d1rect1cn
coincides with the d1rection of ice movement •.However,this ~omponent of
the load tecomes comparable to the action of the current only With wind
velocities over 10 m/s.
A ( ...)sign is taken for tail wind and a (-)sign for head w1nd.
Taking into account that the angle between the surface of the flow and the
water line is small,the component of ice W81Y1t 1n the d1rection of the
current should be v&itten
F"-VA hBL1I.
where I--slope of water surface.
-10-
(11)
.-
./
..:-:.._..~...,.
/
.I
......-~......
.'
Having lost cont i nu1 tr,the ice fields border the edse of the ice cover
which is attached to the shores.At the edse the ice cover is subjected
to cOOlpression,llhen the ice is of reh.t1velr saall thickr.esses the ice
fie~is destr~yed undar the action of CDe9ressive forces for the most part
from bendir~.According to research data debacles develop if the tota.l
forces of friction of water and air curr~nts on the borders water-ice-
ataosphere and the coaponent of welsht in the direction of the current is
greater than the aaxlaua possible load em.
By having data v,w, B, L and h one can evaluate the va.lue of forces which
~o~ote debacles ,and can find the conditions under which debacles develop.
Thus,in the tallwater of the Vo~a GES 1JIleni 22nd CPSU Congress with a
change in wa.ter consUlllption from 4000 to 10,000 m~/s on sections 1000 III Wide
t he current velocity is increased fro.0 .7 to 1.2 a/so Under these
conditions debacles of ice cover are possible with thicknesses of ice less
than »)ca ,
The calculation accepts thd values a l -20' 10 -4 -i1 /a/.,aa-2x10-~/m4,G'n -40 /m3 •
Takin:s into 'account the graph for the weekly pattern of load at the CES one
can ~ypothesize that the most probable are debacles on sections where the
edge coves in the first days of the week due to the sharp increase in
discharges and the small initial thickness of the ice cover which had forllled
in the period of reduced loads (on days off).
The process of h=ocking .vo lves during debacles.The formed ice floes
under the influence of wind and current are shifted and gradually increase
the speed of their mcvement .
In the process of movement t he ice floes .nich possess a varying supply of
kinetic energy hit each other and as a result some of them lose stability,
,'nd under pressure from ice with greater kinetic energy they are tipped on
tr.eir edges and are broken up into parts.In those cases where the kinetic
energy of the floating ice floes is not sufficient to destroy,some ice floes
creep OV:l ;others and their hUlllllockir.g occurs.In hUlllllocking the mOV8l1l8nt
of ice ~·...,.s in the horizontal plane is disrupted,the rear edge of the ice
floe is subMerged in the water ,while the front edge is raised to a height
determined by the mass of ice floe m and the initial velocity of its
movement v,i.e.
(12)
where P--welsht of raised section of ic~floe.
It is natural that the developaent of the hWUlocking process either inhn-
sif1es or dlllinisbes depending on the velocity and direction of the wind.
In the process of debacles the edge retreats and dynaaic thickening of the
ice for_tions occurs ,as well as an increase in the irregularity of both
the upper and lewer surfaces.III those cases where the kinet1c energy of
-11-
'-~-_.
:..,
I ~)",•••_....:
.".'...
,-
..
"..
c~refloatL\g ice aaases is not sufficient to destroy or move stopped ice
floes a con~lnuo\lS ice 1'1eld of ice cakes beS1Jls to fora.As ice ace...ulates
the pressure increases and compression of ice occurs.In add ition to forces
act ing in the direction of t he f low,thrust develops.i .e .,part of the
l oad beg1Jls to bo transaitted to the shores.The resistance of the river
shores depends on the shape of the shores.the t hickness and strength of
th~ice cover,and the nature of its contact with the shores .Qualitative
ana17~is 0:the conditions for t he d7namic i nteract ion of the ice cover with
t he shores permits detection only of t he ge neral relationships between the
forces of res i stance of shores and t he maln de termining factors .
I t i s k nown that debacles are alwa ys accoopanied by heap ing of ice on the
sh or e.Dependi ng on the sh ape of the s hores,curvature of the slopes,as
well as t he strength of the ice the natUle of deforaat ion of t he ice cover
is de terlll lned.On sections with gently slopir.g shores the fie lds an
destroyed froo bonding,or fro lll shearing o ff ur.der t he i nfluence of 'rert ical
components of contact forces.On sections with steap shores destr uctioh
of the ice fie ld edge is oost probable trOIt shearing off .According to
research data,t he s hattered i ce field adjacent to the shore~has a force
effect on the edge less than the monolithic ice field ~hich does not have
a strong bond Wit h the shores.Quantitative analysis of the lII&Xil!l\lll
permissible load on the edge by the shattered field is made with regard
for the ~angential str~sses i n the tricticn water-ice,the forces of friction
on t he shore,and the lateral pressure Ll].
Fcrmation of I ce Jams
~;d e r the i nf luence of the curre nt ar.d i nterac tion with shores the ice masses
which pile up before t he edge begin to thicken.I n those cases where t he
d ischarges increase,at the edge an ice cover bog1Jls to form wh ich is of
do uble or tr i ple t hickness depending on t he initial thickness of ice ar.d
the discharge conditions . This phase of jam forAation usually (loes not
r es ult 1Jl a significant rise in water l eve l.A f urt her rise In water
level and lncre ase in current ve ivcity elicit deformation and compression
of the shattered ice f ield.Essentially a new i ce field is for eed with
thickness and de nsi ty of the ice f loe packing corresponding to the cor.diticns
for a new equilibriu=between the forces of resistance and deformation.
By using the equation for hydrodynaJllic stability of the ice cover ~e (2)
one can co opute under what c cnditions of discharge arod values of lnitial
thickness of ice its separation and subsequent formation of a double or
triple la.yar will occur .-.
For the entire range of change in the water co nsumption during discharges
characteristic for the Volga GES iJaeni 22nd CFSU Congress separation of the
edge on the section near the daa can occur with thicknesses of ice not ·less
than 40 ca (table 6).'"
with Mall 1Jlitial thickness of ice (8-10 CI:I)fOrllled at low negative
tellperatures 1Jl the period of m1n1lllua nightly loads,separation of the edge
-12-
--.--
,.
I
l
r ,~••
Table 6.Characteristic or HydxodylWli c StAbillty of Ice Cover Edge
.,
I'Jln .e".
.,.
.·:c r,I I I••n••• -o.J ••II.~•-=-o.r
0I1I 11 ,0.5 I S 6 •II
0I1I 11,1)6 7 \I 11 2')...,,)o.os 12 IS 21 Y,
100lJU 0 . 10
I ~):!I JJ S/j
12 OIJO 0 .11 2J :!9 ~I 61
IS OUO D.I:!:lG 31 ~8 60
17 0lJU O . I ~J6 47 66 110
KeYI
1.Consuaption,m3 /s
takes glaco with an~'discharge.llit.h an increase in water consuaption toeOOom/s the condition of hydrodyr~ic stability of tOe edge is fulfilled
with thickness of ice 12-;6 cm d~pending on the porosity of the accuaulations.
Conseque~tly,under these conditions formation of a shattered ice field
of double or triple thickness of ice must occur .\lith a further increase
in the consumpt ion of w~~er of discharges ~change in the thickness of ice
also wi ll occur corresporAingly .
Further thickening of t he fo=ed contincous ice field at ths jointing with
the edge of tho int act ice cover occurs as a result of collapse under t he
i nfluence o f a h ydxodynami c l oad,which leads to the foroation of a jam
accuaulation.Stability of the jam accumulations is determined by the
maximum water e xpe nditures in discharge .the morphomet~lc characteristics
of the j am section,and strength and thickness of the ice.The limiting
condition for static equilibrium of the jam accUlllulations is the follOWing
expression [8JI
H i/ii
---236PI'Q ••(13)
where H--depth,feet l B--width of river,feet I \1-0.261 Q--consumption,ft3 /S•
The stability of jams is aa1nta1ned until the current pattern ch9.llges.If
t he expression of the left side is less than 2.;6 the ice ~,cannot counter-
act pressure and is destroyed .Under tailwater conditions the increase
in water consumption during the formation of:jams elicito a redistribution
of the masses of ice and a retreat of the ice cover edge .Evaluation of
the quantity of ice in the jam is made according to the data for changes in
the water-permeable capacity on the jam section,by using the aethod based
on the use of reference CurvfOS [3J.
-13-
....!"',.;....:._~.~~.:;~:;._..-.:.::::_.:-;_;:.c;.-.:. -.:.~~~:----------------.",.--------------
..--,
Tab le 7.Characteristics of Destruct ion of I ce Cov er Edge 111 Tallwater
of Volga CES 1JIlen1 22rod CPSU Co ~e ss
Cl)
('II
(aJ
l)J
('0)
~Jl
(I')
($I
«;;l
(I,.)
IS)
(II
Itl
(ll)
lSI
bot)
(~
l')(u \5)("6l'.rMl ".I".•I,e '.1;",""T....-.........a .
,I"...\~.I:,w•••...,......,..1•.\6 .....~l """'"
_.!Iey_...~"II'II.
'U.......I '7·........1 r K .......
2 :11-61 8:;m I ~'SQ
I
&1 Z!I n 'lJ.a'IOtl.J..1
9:11 -61 10000 01310 62 ~t
I
nn.\bI'''''''3.Or(1)"a,1\,lI lIf
"r()~""
18 '11-&3 121 ~~I 1Soll/)11 .,-n ".1DI ;iKI-.11•.,
~4 'lI-u3 12001 7t'..JO 19 JO t'f'J,.u....h..J
2S.I-I'H 12000 I ;1)(()61 16 Ci'·'."pt" UiII ~.C8CT.1Oro
I 8
if :•.1.]J TIJP
18 ,1I-~1500 6OO'l !In.1Dhit\;,-,,J
~~'II -~
I
13300 IlCWlO 10 3'1 nlJJ....;«u
3 11 -65 12900 7180 -IS 16 Cr......~tJ \U.1 1 v I\patHo.
I I
.1p~~iU"K.l (n~'I"--top"II '
3 :1I1~:1.'111 4 26
r'N 'a:um("\
IOIJOII nO':.:I;I(;';,)
2;1~1 I.ltnl 5-120 U 8 - 10 c'rull 1l ~-":Io:II.J :&TflP
25 .1-6.150m I .;)20 18 t .l ln.1n"......1
26;1 -0'I .l :.~)0%0 I .j.~19 C ,'I An hr U··....1.1:nt\r
19·II -M Ill..'.;';''lO I t 40 IlnJIUl OK k:3
fill ,,69 12 300 ,112tJ ~.,-n n..2 n ll ~:i .;JI."1:?'1-69 .1~,100 rue I w I~-~')n t l.U lliI.;;c.:I
11'11-.0 1 2 :l1 ~I ;~(JI,I I~~')£1..."1.......:1.CP~11 tif""nm
I (:ft·I"-"l~J t·\ln ;·.I".ll1 lll ·)
16 '.11-.1 I I~IO)I jro>61 ~.1 n..:DlliK....l
17,',1.1 -;\12:l()o)11tiO
I
62 ~5 J1n.lItIlAJi::l t nC!:~·Tup ~lIpo-
I
,
n.ul1u·'
19,1 cn 1~050 I 9000 G4 10- 15 Cpu.Itr-.\I ...It.l.'rop
Key.
/i ,Date 8.Debacle
.'2 .Consunrtion of water.C1:1/S 9.Debacle .Re gre ss10n of ~e
3·H ax1Jlll:lll 10.Separation of edge at Svet l yy
4.Dally aver~e "t ar.J u
5.Distance of edge fro:!GES 1t.Separ ation of edge at Krasno-
~am.ka armeysk (r eformat1on)
6.Thickness of ice edge.Cl!l 12.Separat10n of edge .ju
7.I ce .s ituat ion 13.Debacle.s epar ation of edge
(reformation)
14.Debacle (r efor mation)
I n laborat ory stlnies of the ~e chan 1 sm for t h1s comp 11cated phenomenon t he
qual1tat ive chara cter ist1cs we re found for t he ~ocess of jam accumulat10n
forlllat lon and val ues f or t he Froude number were obtained f or wh ich there is
fo r mat 1on of a d ouble and t riple layer of ice f ield.as \18 11 as separat10n
of the ~,and formation of ·jam accumulations [10J..
One s hould d we ll on the res ults of f ull-scale observations made by the
Volgograd Kydrometeorolog1cal Observatory of the cond 1tions for t he formation
of jam acc 'lIII ulat1ons dur 1ng t.he movement of the ice cover edge 1n the
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tal~water of the Vo~a CES 1I:enl 22nd CPSU Congzess.Analysis of the
uterWs for the l1-year perlod of observations (table 7)revealed that
ln t~e tallwater of this CES separatlon of the edge always occurs If t~e
cor~ltlon for hydrodynamlc stablllty o!the edge (2)ls not fulfllled.
Def'!ndlng on the aI'lount and duration er dlscharge In some cases there are
debacles (1960-61,1962-6).1968-69.1970-71).whlle ln others reformatlon
of th6 lce cover takes place (1964-65.1969-70)and formatlon of jam
acc~ulatlons (196)-64.1966-67.1967-68.1971-72).The edge ls stable lf
lt is formed wlth water consumptlon and temperature condltlons that guarantee
the n'!cessary thlckness of lce for_tions.DeFendlng on the c~1m&te
cor.ditlons of the wlnter perlod the jams are formed on var!ous secUons along
the ler~th of the tal1water.In a war:wl~ter the jams for~as a resclt
of a ~hlft ln the lce cover edge on the sectlon of dlurnal lag tlae from
t h~1am.thus governlng the rlse In ,~ater level whlch ls the caxlaum for
wlnter.The slte of jam formatlcn ls for the most part a sectlon ).5 ~
below the water statlon Svetlyy 'tar.The greatest jam was observed ln the
wlnter of 1971-72 durlng whlch the water level at the Svetlyy 'tar water
statlon reached ?eJ cm (only 47 cm below the helghest observed ln the sprL~,
rl~~tide).In a cold wlnter the jam accumulatlons are for~ed on the
secticn near the dam d~lng acute dlscharges and small thlckness of the lce
cover .Thus,ln the wlnter of 1966-67 a jam of 16.8'10 6 T of lce was formed :
15-2~:tn from the CES dam.An lncrease ln the water consll1l\ptlon durll'~the
for~~lon of lce jams produces a redlstrlbtu10n of the masses of lce and
an in~rease ln the capaclty of the jam.whlch leads to a sharp reductlon ln
W1nter coefficlents.The aJl:ount of the greatest jam level ls 1n direct
depen1ence on the amount of maximum consumptlon of water l5].By exam1nlng
the entire set of condltlons that determlne the dynamics of the lce cover .>
~e ln the tallwater one can establish the lla1ts for regulatlng the CES
operatlr~pattern durlng the lce cover formatlon ln order to prevent the
gen"ratlon of powerful J=accumulatlons.The solutlon to thls task must
oe baLed on the condlt lons for the stabilizatlon of the lce cover edge
dependlng on the amount of dlscharges and the weather condltlons of the
wlnter perlod.
Concluslons
On the baslr of studles on the dynamlcs of the lce cover edge the followlng
pecul1arltles were found ln the formatlon of jams ln tallwaters,
1.Formatlon of lce jams ln t&1haters ls a consequence of the dynamlc
destruction and separatlon of the edge wlth lncreased dlscharges .
2. The process of dynamlc destructlon of the edge evolves by the formatlon
of cracks along the shere,debacles.and hUllUllocklng on the sectlon wlthln
whlch durlng dlscharges the slze of fluctuatlon ln the water level ls
)-4 times greater than the thlckness of lce on the edge during its formatlon <
:3.Jus are formed at the jolntlng of the intact lce cover and the
snattered fleld under the influence of the forces of the flow and pressure
ot the lee fleld whlch exceeds the resistance of the ice.
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4.Th e aaount o f the greatest j3ll level b i!l direct.deper.dence on the
aJlo unt of aax1Jl ..w.ter cOIl8U&l'tion in the pe=iod of jaa for:aation.
5.A ~!.nc=ease in ~~schaJ:ges :ur ir~the fO::-;::'ltion of ice jus ;!romotes
t he increase in capacity o f th"jall,and as a consequence a reduction in
the winter coef!'icien~s oc ;urs.
6 .Regulaticn of t he CBS rl)ut,ine de pend ins on the conditions for ice cove!"
edge forMati on o n t he section with1n the d~n~l lag time is a ndcessar,
condit Ion f or t he n ovement of the ~e !.n the ta.11~ater vlt1:o~t ~far:atlon .
~.
.2.
.,
~.
BI!lLI~llAFIi"I
:ae!"den;,1kov,V.P .,~ooel Stl:dles on the lIechaniSlll cf Ju Fornation
to S ~bst,antiate ?l ans '!'or Keepir~Ice on the Dniester and Jeterm1r~tIen
of Ice Loads,"TRtrul CC I,:/0 2l9,1974,P J1-J.5.
Cotlib.Ya.1 .1 Y.uz '~in,I.A.I Razcrenov,F.r .1 ~"4 Soko l'n1kov,N.II ••
"J:~turn:JYe Issledovaniya fri pro,ektirov":l11 'CES"LFull-Sca::'e Stl:dies
ln ?:!.annillf;CES=,:.eningrad,Cidrometeoi:o:dat,1971,2e8 p.
Doncher.ko,n.V ••and Chachina ,N. S .•"£valuation of Ice Jall Accumu-
lations in CEsr Ta.1111aters by the Hydraulic lo!~thoo,"TR l'DY CVI,1:0 192,
1972,p 5J-65.
/
4.Dencher.ko,R.V..and BaJusova,(I .I . ,"~aluit.~o n of t he Change in
"Cond itions fer I ce Jam Fo!"mation in the Ta ilvat er of Volga CES ~enl
22nd C?S'J Cor.gress."TRUDY CC I ,No 201,197),p 65-91.
5 .Donchenko,il.V.,"Laws Covernir-6 t he Formation of Ice JaJ:S in CES
Tr.1lwat lrs,"TRUll'!eel,No 219,1974,P .56-71.
6.Kachanev,L.:-!. ,"The ory o n the Strength of the Ice Cove!"d LTi ng fl uct u-
a t io ns in j(a ter !..e ·/e l,"TECR£l'!Ql.E5l\A YA MErECR OLCC IYA,I/o :;-0,1 ~7,
P 29-41... .
7•.Korzhavin,K.II.,"Vozdeystviye l 'da no L'lZhener n:fYe sooruzh3niya "
[Ufect.of Ice o n Engineering Structures],I::d .SO AN SSSR ;1 96 2~20C p .
8.lIishel',B .,"Static Equl1lbrium durlr-6 Ice Flow,"in Eleventh Congress
of t he !nt e=nat l ona:'Assoclatlon for Hydraulic Research ,l.en lng!"ad.Vol 5,
.1965,P 69-70..
I
9 ~·IIbhel'.B.,"Crlterion for ilydrcdyllaJlllc Stab1llty of Frontal Ed«e of
Ice Cover,"ln Elaventh Congress of Internattonal Assoclati~n for
Hydraullc Rese~ch,Lftningrad,Vol 5 ,1965,P '69-70 •
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10.Fllippov,A. 11.,"Experl.Aenbl Studies on Dynuics of Ice Ju ~'ormation
in CES Tailwaters,"See this volUlll8 of COSUIl.'.RsrvElmn CImOLOaCHESKTI
INsr!TI11'.TRUDr .
U.Shanit~n.P.A.,"Ice Effects or.Concrete Sl<:;>8 Covering,"CID!IO-
TOOlNICHESXOYE srROrrE!.'srvo,No 8,1960 ,P 28 -:)4.
COPYRIGHT:Notice ~Iot Available
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