|
<br />. The-graph shows
<br />what release patterns
<br />at the dam would look
<br />like during a typical
<br />sUQmer week if lake
<br />Powell were at a low
<br />reservoi r elevation. a
<br />condition not likely
<br />to occur until the
<br />next century. The
<br />solid line is an
<br />actual historic
<br />pattern and is
<br />representative of
<br />current conditions
<br />while the dotted line
<br />is representati ve of
<br />flows that \1Ould occur
<br />with the 250-MW
<br />addition. The caps on
<br />the solid line signify
<br />the extra power
<br />derived froo rewinding;
<br />the existing
<br />generators. a projectl
<br />nOli unde"",ay. Thi s:
<br />extra pO\1er is shown,
<br />bei ng used on Monday
<br />and Tuesday and is
<br />refl ected in the
<br />24-hour hydrographs
<br />below.
<br />The 40.000 cfs
<br />releases shown here
<br />would occur mainly in
<br />the sumner and only
<br />under low reservoir
<br />conditions. Historic
<br />minimum releases of
<br />3.000 cfs would be
<br />mai ntai ned a 1 though
<br />their
<br />
<br />Preliminary
<br />
<br />Flows
<br />at Low
<br />
<br />Reservoir
<br />
<br /> TYPICAL GLEN CANYON RELEASE
<br /> SUMMER SEASON AT LOW RESERVOIR ELEVATIONS
<br /> .... , 1M I '
<br /> . , I ~ I" I
<br /> ~ !;.p, iI' ~ "oo
<br /> ,I ~
<br /> """ r~"i' It\! -
<br />.,; !Bl' .l I '''''
<br />..: ir: I r~! l1
<br />u .... . '. ""
<br /> WII ;, fgjl ':;1 [),: I'
<br />" 01 !01 ~;: ~ OM
<br /> ",> r~
<br />i;l""" :i I r1' ~/, I !~!I r;~
<br />~ ~ i ' "" ~
<br />w M\: r~ ~
<br />~ : I ; 1 ; ~
<br />w " , ;-',.< "" ~
<br />~- M ~
<br />r ' !;. i ~, ~i I, ~
<br /> ~
<br />~ I , ' "" ~
<br />0 " :11 r
<br />z '5OOl
<br />0 , , !" ~ I ~ 1 ~ ".
<br />~ I
<br />z 1,1 i
<br />~ i
<br />u "''''' , , , ""
<br />z ~I v;.t; , ,! Wi i ' 1'/
<br />w IN, <ff-
<br />~ i ", ""
<br />~ 500l ij':-j (/! I I' 1
<br /> I'f ,,' ! I I I 'oo
<br /> I I
<br /> , , ,
<br /> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ nnnn
<br /> SUNDAY I'\OmJRY TUESDA't loI[D~~509't Tl1iJR5CA't f~!ORr 597URQF'l'(
<br />
<br />TIP I C~" RELEASlB.NO fLO~ PATTERNS
<br />APRIL R'm AUGUST LO:l RES ELE"./
<br />GleN CA,VlOV O~M RelEASeS
<br />
<br />.,
<br />
<br />II.,' SPRING '---I..-i Fig. 1
<br />"I g. sut'.I1CR I I 'I,'z I I I
<br />
<br />~, .i. 5l'~~" 250 ~l'~+,+-n
<br />.. I , , ~;,a 2~~\.-i=cpJ
<br />.. ' I ,I I =H1WJ I/.~(/III t; I <I
<br />, J' 'J i! I I ';[0/.'%/ <<9;:r,-c;-r'l
<br />g . I I '~~~i!-I;: + ~~ 'iCI?r/l~, ,
<br />": lTTl-j 1- :TT1-i-~ :r.~I-l- rrr-!'""i '-.r~-i'
<br />- "'r-rt ri. I -rr:~l-\1 /i'~H
<br />, I. ,~" rm---.... -\\.~' "
<br />~ 11..1 :-H !;: i tiJj) : I 1j:;vl ;,:\-j
<br />",P.' . Ii' i i'j'l! I . " '--,-~~~
<br />~~~,; J
<br />"~J~f~~ f'< III . i r L;"'!_. 1-0 :. \,
<br />",>,--'.Ji"',...":!,,, . . '"
<br />" L t' It' 1 f,
<br />! I r-:lTl',. r
<br />LI ' -, - ,
<br />I~-~ t'it\ t2-~ E~ 11-1fI
<br />lC.JCWll
<br />
<br />Figure 1 is the release patt~rn at Glen
<br />Canyon Dam on the same Wednesday depicted
<br />above. The "SUtlMER 250" release peaks at
<br />3PI4 and is 17.000 cfs higher than that
<br />....hich occurs with present sumer
<br />conditions. The large difference is due
<br />in part to the absence of the generator
<br />rewind flows in Wednesday's release. Note
<br />that the difference between the tHO;S
<br />[about 7.000 cfs on Honday and Tuesday's
<br />releases on the graph above.
<br />
<br />TYP'CRL RELEASE AND rcO~ PA)T[ANS
<br />IJ[ 5 r[R~r lOCATEO 15 M! L[S 8[:_Ow Gl.6J"CANYON DAM
<br />QPr>10xl~Al[ fl.O;';~E fRQ~ G.JN ~ili:Umj OA~ . 2 t)Ot~
<br />
<br />.,
<br />
<br />10- SP11'~G Fig, 2 i
<br />JiG/i:.;_ 5:J~:;~CR I t I I ~
<br />,,;",' SU','c'i 2S0 ",' '-tl~/;fltP
<br />:-'--- I I ';1I!%k;' ~,-,
<br />"j-'--;""'-,--[- -1-,' ./',11;7%7 -,I
<br />I I I ' i I/"/~VI;:,/J I
<br />1 I' I ;;z W<<%%I!I~' "
<br />}0.1;-" , hNr/I~j>/: 11//.1// ..--
<br />, , i, I I YI/fl",lfl. ,f,rl! I/I~'
<br />rTl I I I e.f.'"r-I ..~.,~Y I I
<br />~.T\! ' , I I I-Ti
<br />!: ~/i1;, I I I, ,/.,; i-T....-r:-;TI~
<br />~ :uFt,~~, I I ' I I ~,I L,i Jtj;J-I-~r-;-nl
<br />1\';;1,'00,' I" I 'l?71 I , . .Arl;:-'
<br />'Jlr\~;~,i'l'0:b~hL' .:t.ifi'i -;-1 I : . ' ' fitlli
<br />G~: \:;:::(: V~~;;.~/;?dt(";r~);f I' r-r--' ' jr--J-rI'
<br />u'~';':"""","'iI,,,,,.r,,~j,;r,.~j -' i
<br />, , .. \.,I./I///liUV!f/l/.)t ". " , .' I I
<br />j-'-N~'I",/J~~!-/ij~\ <-' , I
<br />
<br />:: r:-l-r1i~~~i-:: ' i H rH-41
<br />I"""" 6-fr. !t '(0\ ~.Pr, Il-ffl
<br />.cxS()<1
<br />
<br />The jagged appea rence of the
<br />hydrograph in Figure 1 has
<br />smoothed considerably by the
<br />time the flows have arrived at
<br />Lee's Ferry two hours later.
<br />TIle "SUr-U~ER 250" peak flows
<br />have diminished to about 34.000
<br />cfs. Future "SUt1MER 250" low
<br />neVis. <trriving in the morning.
<br />are about 5,000 cfs 10h'er than
<br />present "SlJolMER- low flows.
<br />
<br />durations would at
<br />times be a few hours
<br />longer than at
<br />present.
<br />Wednesday's
<br />release pattern on
<br />thi s graph is
<br />displayed again in
<br />fi gure 1 below,
<br />Figures 2-5 show flow
<br />patterns at points
<br />downs tream du ri ng the
<br />saoe 24-hour period as
<br />in Figure 1 and
<br />reflect the continual
<br />da~pening of the
<br />release pattern as it
<br />travels through the
<br />Grand Canyon.
<br />The figures below
<br />are hydrographs of the
<br />same 10cRtions
<br />presented in
<br />Newsletter #5. Summer
<br />flows at present
<br />(labeled "SUI~lER") and
<br />in the future with the
<br />250-MW addition
<br />(labeled "SUi'lMER 250")
<br />are shOlJn. as in the
<br />\.!eekly h,ydrograph.
<br />Only a single spring
<br />fl ow is di spl ayed
<br />because future spri ng
<br />flows at low reservoir
<br />elevations with the
<br />250-MW addition would
<br />be similar to present
<br />conditions.
<br />
<br />,The 1 i kel i hood of a 1011
<br />reservoir is shown on this
<br />chart ~Ihi ch depi cts the
<br />probab 1 e occu rence of futu re
<br />Lake POHell reservoi r
<br />elevations. It was derived by
<br />standard techni ques for
<br />predicti ng the probabl e
<br />occurence of hYdrologi c events
<br />using historic data. As
<br />explained in the last
<br />newslettel', l'Ie define a low
<br />reservoir as one below 3,580
<br />feet(shaded area) since below
<br />that elevation a maximum
<br />release would have to occur for
<br />full power production. Lake
<br />Powell has a maximum elevation
<br />of 3,700 feet and a minimum
<br />elevation of 3,374 feet. It is
<br />nOli at an elevation of about
<br />3,680 feet.
<br />Lines A through D separate the graph into four secti ons acco; di ng to the probabl e
<br />occurence of a given reservoir elevation. In any year, 25% of probable elevations are
<br />above Line A, 50% above Line B, 75% above Line C and alr.lOst 100% above Line D.,
<br />Looking at Line D, it is evident that an elevation below 3,580 feet is unlikely
<br />until about the year 2023(al"ro\'il. A considerably higher elevation is more likely in that
<br />and future years.
<br />
<br />37'0
<br />
<br />Probable lake Powel Elevations
<br />
<br />.
<br />.
<br />>
<br />~370
<br /><
<br />~
<br />
<br />0,
<br />~-
<br />
<br />~r ,
<br />I I I I..
<br />:: ~:
<br />
<br />-...:.....:....:.
<br />
<br />z
<br /><
<br />.
<br />::1:3650
<br />.
<br />>
<br />g
<br /><
<br />~36C'\
<br />=
<br />
<br />3550
<br />.~~H~ :::::: "',,' :::::
<br />
<br />z
<br />o
<br />~
<br />~ 355
<br />~
<br />
<br />.. I '
<br />I.. 'j"
<br />
<br />.
<br />
<br />'I:'
<br />
<br />.. I"
<br />, ,
<br />
<br />,
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<br />
<br />'I'
<br />, ,
<br />'. . I
<br />......:
<br />
<br />c
<br />
<br />:,
<br />
<br />-=--.. '.
<br />""'''''''''''...~''''~:''''''.<
<br />,''-'-,~'',',,'',''',--,.' ~"
<br />"," ~,~,~, ,"" "','" .,
<br />~~~~~.~~~~~~', ,: ~~~"
<br />
<br />."", ,,"~
<br />~~~~i ~~~~~
<br />'~.~'~ ~::~~~
<br />
<br />',',',',', ~~~~~~ ~,:,'~.~,~,~ ~~~~~ ~~~~~~ ~~~~~ ~~~~~~ ~~~~~~ ~~~~~: ~~~~~ D
<br />",', ,,"" "',' """ ,~'" ",,,-, "~"
<br />~~~~~~ ;~~~~; ~~~~> ~~~~~ ,"" ~~~~~~ :::::: ~~~~~' ~~~~~ ~~~~
<br />"'" ,,'," """ ;~~~~ ~~~~~~ '~~~~~ "",, ~~~~~~ "'''',~~~~~ '"''
<br />
<br />3500
<br />
<br />.
<br />.
<br />.
<br />
<br />.
<br />.
<br />
<br />.
<br />.
<br />
<br />ITPICAL RELEASE AND fLD~.JBITERNS
<br />~ANCE RArD lOCIlTW 77 MilES eCtOU[LS fERRI
<br />APPRDiIM,lTE rlO~ TIME fROM, GLEN CAIiION OA!~ . 11-19 "OVRS
<br />------ - !
<br />(l,oT?
<br />1.0- SP,11'.G [6H--LL
<br />"D:!~-5U~t1m H-L'
<br />I,'. Su,~,~,Ji 2S0 'I I-LI
<br />"I UIrT'in-1 .
<br />u[l-D=cr=c;~ :-
<br />1-1++:' ~~'~!AI
<br />".'@].I.-'''liN&<;';:;;<
<br />-: Jifi%E+' W
<br />,", --fif017:l' 'I
<br />; ,..r:r~ljr1~" ,
<br />i IJ1&2i,{ IT
<br />,,,:r~1".~(:$,f,', ! IT
<br />.. ~fu@,'T"-
<br />. !.1 I I
<br />
<br />lIP ICA.LB.ElEA.5E END rlO~ PATTERNS
<br />BEDRDCi R1P 1 0 LCCATED 1 JO MilES 9ELOR LEE S fERRY 'I
<br />RPP,lOi WoRTE r,o~ TIrE rRDM GLEN CRNYON OrlM ' 2S- 29 "GURS
<br />
<br />Fig, :3
<br />
<br />
<br />..
<br />
<br />I I I
<br />-r ~r-
<br />H...L:.+
<br />I. ! ,
<br />=r=,
<br />
<br />
<br />,,'
<br />
<br />I; I
<br />->1
<br />
<br />
<br />,
<br />L i I
<br />I I-r:-T
<br />--r-:-;-
<br />
<br />12-....1;
<br />
<br />I
<br />l
<br />
<br />--'-'
<br />'H
<br />
<br />u
<br />~2.~
<br />
<br />12-,...1
<br />
<br />,,~
<br />
<br />i2'~
<br />"""'"
<br />
<br />''''
<br />
<br />$'''''
<br />
<br />12'r<<Jo
<br /><1><""'
<br />
<br />,,'"
<br />
<br />The peak flows appeari n9 in the
<br />morning at Hance Rapid are
<br />Tuesday's peak. releases from
<br />the dam. The 40,000 cfs "Sur'1MER
<br />250" release has diminished to
<br />28,000 cfs and is about 4,000
<br />cfs greater than present
<br />"SLMMER" flows.
<br />
<br />The peak. f1 ows here are agai n
<br />Tuesday's release from the dam.
<br />They have dimi ni shed further by
<br />the time they reach Bedrock
<br />Rapid. At this point the
<br />general flow pattern (maximum
<br />and minimul':'l flows and the
<br />di stance bebleen consecuti ve
<br />peaks and troughs) is well
<br />established.
<br />
<br />o
<br />~
<br />
<br />~
<br />
<br />'fUll
<br />
<br />.
<br />~
<br />
<br />.
<br />,
<br />~
<br />
<br />.
<br />"
<br />~
<br />
<br />o
<br />~
<br />
<br />"
<br />o
<br />
<br />TYP[CAL RmliSE AND flO~ PATTERNS
<br />lAVA fALLS RAPID LOCA,[D 179 MILES BeLO~ lE['5 rERRY
<br />IiPf'R'1i1'li1fE fLQR me rRO~1 GLEN CANYGN OA,~ . ]]']9 HOURS
<br />
<br />..0
<br />
<br />Fig. 5
<br />
<br />1m-SPRiNG
<br />:Ui'~l. SUm~lR
<br />I ,- Su,,~[ii 2SD .
<br />1/,', I ' , ~
<br />H-~'~! ,,'
<br />JI.I . ~ '. , I
<br />1 01~'::t;~. _: I
<br />".f!?ri1J~
<br />I; I! ,-, i
<br />iI.o4,' ~
<br />" n--t-
<br />;....~II.I!i..f-'
<br />o I ,. in
<br />.J I ---i----'--
<br />"-ll.I-+-'! ~
<br />1 l-t-I !
<br />II I I j
<br />I'
<br />
<br />N,
<br />
<br />; ,J
<br />
<br />
<br />,.
<br />
<br />"
<br />12fJl
<br />
<br />,,~
<br />
<br />lHool
<br />"""",
<br />
<br />''''
<br />
<br />"...
<br />
<br />The peak flo\>/s arriving early
<br />in the morning at lava Falls
<br />Rapid are Monday's release from
<br />the dam. Low flows occur in the
<br />afternoon. The .SUMMER 250. low
<br />flows are almost 4,000 cfs
<br />lower than present "SUMMER" low
<br />flows and arrive later.
<br />
|