HomeMy WebLinkAboutSusitna Hydro Response of Aqautic Habitat Surface Areas in the Mainstem Discharge April 1985SUSITNA IIYDROaECTRIC PROJECf
ROIpon ..01 Aq""tlc Hob ltlt Surf ..1 Are..to
Mainsi'.DIsc:h"ge In 111.Te lk ..tne-to-Oevl l Canyon
Reach of the Susltna Rlvor, Alalke
By
SIloron A.Kllngo r-Klng.I IY
E.'body Tr lhey IIlId M .ocl.t••
Undlr Contract To
HarzlrEbe sco Susl tn.Joint Venta""
Prepared For
AI ..k. Power Author i ty
Draft Ro~ort
Apri l 1985
..
5us SO'I
SUSI TNA HYDROELECTRI C PROJECT
Response of Aq uatic HabItat Surface Area s to
Maln 5t.DIs,ch8rge In the Tal k8 etna-to-Oevl l ~nyon
Reach of the Susl tna River,Alaska
By
Sharon A. Kli nger-Kingsley
E.Wood y Trl hey and Assocllrtes
Und er Co ntra ct To
Harza-Eb asco Sus lt"a Jo Int Vent ure
Pre pared for
'1 ••k .Power Author I ty
Dr af t RaJ.'...-f-
Apr !I 198'
ACKNQl LEDGEMENTS
This wc:rk Illes undertl!l ken I n coo perat ion v l th ttl.Al aska Depart. ent o f
Fish and G811 8 Sus l t na Hydr o Aquati c Stu dy Team BR C!R &M Consul tant s,
I n e.,Anchorage .AI ZIska.AOF &G SuHydro per sonnel partl cl pared In t he
derr vlltlon of defini tions for the va r ious habitat ty pes a nd t he
d eve l opment of the aq uat ic habitat cl asslf lce t lon key .lhe a erial
photography .I~slon s .ere sch eduled through Mr .Steve Bredth auer,R &M
Consulta nts,Inc.He did e n 8)(ceptlonal Job g iven the highly varl eble
nature of streall 'l ow a nd .e at her c ondit ions. Aer-Ial phOTogr aphy va s
flown and phot o e cs et cs and enl argements pre pared by Ai r Pho to Tech,
Inc., an d North Pacifi c Aer i al Surv eys ,I nc. , Anc hor"'a ge,Al aska ,under
co ntract to the Harz a-Ebesco Susltna joint Yentur~
TABL E Of CONTENTS
e-
INTROllOCTION ..•••..••••..•••....•..•••••..••••....•••..••••• I
I€THCOS 2
Habi t at Types Designa tions •••• •••••••••••••• ••••••••••••••2
f iel d Methods 3
Of f i ce Procedures ••• ••••••• •••••••••••••••••••• ••••••••••• ),
Photo P I etes end EnI ergements.•••••••••••••••••••••••}
Habitat Type Boundar ies •••••••••••••••• •••••••••••••• ,
Olgltlz Ing ,
Data Base ••• •••• •• • •• •• ••• • • • • ••• • • • • • ••• • ••• ••••• • • •7
Analysis Procedu res •••••••••• ••••••••••••••••• •••••••7
RESULTS e
DiSCUSSiON 10
REfERENCES 17
APPENDi X 18
I NTROOUCT ION
The proposed Susltr.e hydroelect r ic project wil l a lt er t he nat ura l
s t re a mfl OW regl ••s of the Susltna R i ver.The river 58g ...e nt do wnst rull
from Dev II Canyon t o t he Chul itna R iver c onti uence (lei ke.tn e) 'I OUI d
experience notable a lter at ions In natu r ally occ urring str eamflow
patt erns,due to Its proximity to the proposed damslt. ,a nd the limited
a mount of Infl uence th at t ributary Infl ows neve on total dl5Charge In
th is r iver segment.
With -p roJeC T d r scn er-ges are expected to be lower t hen natura l I y
occurr ing f lo ws dur ing s umme r end hlghe,..In the .I nt e~These a ltered
flow s ar e expected t o af fect t he amo unt end seasonal avaI lab ili ty of the
a qua t ic hab Itat s present I n the river.This report prov ide,locat io n
an d area l extent of various aquat ic hab itat types at d ifferent Illlinst em
d I sc har ges.These dat8.In comb i na tion wit h the r es ult s of other
st ud ies f ocu sing o n b iol og i ca l fe 8t ures o f ha bi tat s presen t In thi s
s egment of th e r iver, will faci l it ate f orecasting t he e f fects o f a ltered
s treamflo ws on th e avai l abili t y o f 8q uat lc n ee t r er t o e nee r ce c us an d
res l dent fish.
Aer ial photography Interpretation.along wi th field r econnaissance.Is
b ei ng u sed t o I den ti fy and map va r iou s aq uat ic ha bitat types In the
Ta l kee tna-t~Oevl l Canyon reach of the S usltna River (a lso re fe rred t o
85 t he middle Susltna River). In 19 &4 Initia l work on aquatic hablt8t
mapping and 5 urfece area Ileasurements determi ned t he location 8nd a mount
o f v ar io us aquatic habitat t ypes at malns t e .d ls ch8r g8s of 2',000,
16.000 ;12,50 0,a nd 9,000 c t a,85 meas ure d at the U. S.Geolog ical
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Survey (USGS)Gold Creek gag ing st at ion (Kl ing er llnd Tr lhey 1984 ).
This reporT presents t he surface area response of aquaTi c ha bitat types
t o m81 nstem d i scharge at f our addi t iona l streemf l ows: 18,000. 10.600.
7 .400,zmd 5 .100 cfs.The 18,000 ch d ischarge f all s within the 16,000
to 23,000 cfs r ange ••here ~veral s loe s loughs and si de channels become
Inundated by lIalnstem water. The low e-three discharges "rov ld e a good
basis f or evaluating low flow cond Itions In the river.
This report discusses the four sets of aer ia l photogra phy analyzed In
1985 and pr esent s the su r f ace a rea mea s urelll en ts I n c omb Inat Ion .1 th
those a na lyzed I n 1984.Ho wevcr ,surface area me asu r eme nt s o bt ai ned
from the 9 .000 cfs photogr aphy have bee n omitted from th is e valuat ion.
The s urface area me8surements ob t 81ned from the 9.000 ch phot ogrllpny
were s us pe cted o f be i ng somewh at Inacc u rate due to di st o r tion s
associ ated wit h Ice an d snow cover (KI I nger a nd Trlh ey 1984). The
presence of sno w and Ice alade It d ifficult t o accurate ly de termine th e
wat er 's edge an d eeesur e the we t t ed surfaces .The 1984 s ur fl!l ce area
measurements obtll ined from the 9.000 c fs photography were co mpared wit h
198' su r f8ce 8re8 dat 8 ob ta ine d 8 t 7.400 a nd 10 .600 ct s.The adver se
Inf l uenc e of shoreline Ice a nd snow cover on t he eccuracy of the 9,000
c ts data set I s qu ite ev ident from this cOtllparlson (Kl inger 198').
Su rface ar ea mea sur eme nt s for t he s eve n d Isc har ges ev a luated In t h is
report pr ov I de an ad equate bas i 5 for I de nt I f yIng the response of
specific areas t o streamflow reductions.as we l l as for quantifying
change In wet ted surface area of middle river h8b ltat types oyer 8 breed
ra nge o f s tre amflows.Although weTt ed s w t eee area may be used 8 S an
Indicator of habitat a V81lablllty.It does not rep resent ha bI t at
quality.This report does not c ontain a ny st.teCi ents concern ing the
s ui ta bil i ty ot the various ha bitat ty pes tor fish, ncr doe s It ad dress
how the qu ality ot theee hab ita ts !n ay r e spo nd to ch anges In malnstell
dischar ge.
MElHOOS
Hab Itat Tvp: De5lg not 1OO$
The t ota l wetted s urfece pr ea o f the midd le Suslt na River was class If ied
Into six ge ner al a q uatic ha b itat t ype s b a sed o n cr i te r ia v Is ua l ly
e v ident In aer ial photograp hy or hel i copter ov erf li ghts :maln stem, sI de
channel ,side s lough, upland slough,tr ib utary mout h,and tributa ry.
These ha bitat types represent p hys i c al charact er ist ics o f t he
env ironment a nd do not necessarily depend upon any particular degree ot
uti I lzatlon by 11.1\.
The fol lowi ng brief des cr i pti ons were used to IdentIty the six aq uatic
habi t at types eval uated In th is s t udy.These def initions are li mit ed to
v isu a ll y r e cogn izab le phys ica l c h aract er ist ics present during Ice-free
co nd Itions and that are easily Identified from t he air dur ing he l icopter
reconn aissance flights .A eer-e det ailed descript ion o f each aquatic
habitat type has been pre pared by th e Alaska Department of F ish a nd Gam e
(1983 ).
Haln$t Qm habi tat ty pes a re th ose c hanne ls o t the r ive r that
normal ly conv ey s tre amflOW t hroug hout t he e nt ir e ye ar .They a re
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visua lly recognizable by thei r turbi d,g lac ial water and hi gh
vel ocities.
Si d.Cban nel hab itat ty pes a r e a lso c ha ract er ized by tu rb id,
glacial water.Veloc it ies often app ear l ower t han In malnstem
si tes.Side chan nel habit at Iley exist In wel l-def Ined channel s or
In areas typifie d by n umerous Islands an d subm erged gr avel bar s.
When the upstrea.be rms o f si de ch ann els a re dewat ered a nd the
channels conteln clear we ter,they are class if ied as s ide s loughs.
S'd Q Sl ough hab itat types c ont ain c l ear water.Up welli ng and loc al
s urface ru no ff are t he pr Imary s ources su pp I yI ng c l e ar wat er t o
t hese a reas.Side s loughs have non- vege tat ed upper thal wegs that
are overtopped du r ing per iods of moderate to h igh malnstem
dlscharg8~When thes e area s a r e o ver top ped they c onvey tur bid
wat er lind are t hen c lass if ied a s si de c hannels.
Uplond 'Iougb habItat ty pes a lso contain c t ee r-wliter lind depe nd on
up.e l II n9 and/or l oca l surf ace ru nof f f or their wat er s o ur ces.
Up Ia nd sl o ughs poss ess vegetated upper thai wegs that ar e 581dOll
overtopped by malnstem d lscharg&
T r ibut ary mou th hab itat types are clear wat er areas that e xist
wher e tri b utary str eams flo w In to mal n stem or side c hannel
hab itats.Th is ha bitat type Is manif est a s a clear wat er p l ume
extend ing ou t I nto the tu r bi d r ece ivin g wat er .Tri b uta ry mout h
hat lt at al so extends ups t ream I nt o t he tributar y to t he upper
e x te nt o f a ny backwa ter I nf luen ce that might e xist.The sur f ace
area of tr ibutary mouth habitat Is af fected bot h by tributary
d ischarge and maln stem stage.
T rlb yt ory hab ita t t ypes are t ho se reaches of tributary s t re ams
up stre am o f the tr ibutary mouTh habi t at s.Tr l but ery hab itat types
heve not been evaluated I n this analysi s because tributary habitat
Is not I n fl uenced by mal nst em st a g~
Non-we tted areas were cf ess l t l ed a s e ither vege t ated I sl ands or gravel
bar s.Areas w ithin the control c orr idor that were quantif ied but not
r-et even't to t r..,sur f ece area analysis were Classi fied as "ba ck ground".
f igure 1 pr esents a descript ive k ey u sed to c lass i fy ar eas of t he mi ddl e
river I nto habi t at t ypes. This key was ad apt ed from the Al as ka
Depa rtment of Fish and Game Sus ltna Hydro Aquatic Stud I es (1983 )
classification Index for aquat ic habitat types.
flold M@thods
Camp I ete photograph I e coverage was obta I ned for seven lila I nstem
d ischarges In the Tal keetn~t~evll Canyon roach of the Susl t na Ri v er.
Black-and-w h ite aer ia l photographs .er.obta ined at an approxima te sca le
of 1 Inch .1000 teet,with a 60 pe r cent ov er l ap bet ween ad j ace nt
photos.The dates of the photography and mal nstelll discharges as
mea s ured at th e USGS Gold Cr eek g agi ng station (No.15292000 )at t he
time of photography are presented I n Tab le I .
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'r ee te 1.Oates and ",aln stem d i sc harges at wh i ch aeria l phot ography of
the Ta l keetna-ta-Devll Canyon reach was obtalne~
JlA1I PI$<;b§rge (e l$)
6- 1-82 23,000
8-24 -80 18,000
9-11-63 16,000
9-6-83 12 ,500
9-9-64 10 ,600
10-4-84 7 ,400
10-14-84 5,100
Helicopter reconnaissance fl ig hts ~ere co nducted ov er th e Talkeetna-to-
Devil Canyon reach at maln stem discharges si milar t o those a t whi ch the
aer-I al photogra phy was o bt a I ned.Our I ng e ach of th ese r econnaI sse nee
fli ghts, aquati c habitat ty pes werG Identified using the key prese nted
as F i gure 1,and their l oca ti ons were mapped on 1 I nch .1000 feet sc a le
bl uel Ine prints o f the Susltna River.Dewatered g r ave l b ers and
streambank areas wer o ske tched o n the blu~l l ne pri nts a s wer e bo unda ri es
o f the var ious hab itat ty pe.
Qfflce prQCedyres
Pbgto PIAtOS o nd F n l o rg~
Photographic mosai cs .ere prepared from th e o verlappi ng black-end-w h ite
photos to prov ide continuous I Inch ·1000 feet coverage of the
Tal keetn~to-Oev ll Cenyon reach for eac h of the 58ven d l schal"ges.The
ITotal SUr1ICI Ar"l01 R....et'Con"dor
Oft PholO Moulcs
IT'''II W,",d I Total MOtto_lied I
Surf-e:,.lo r..I I Svrt'C"C Are a
I~Tuft)id,elKla'
WIt.r I W•••r SurflCl ... .Surf'c••r.,
'lI9I1al,d ,zpo&ed
I blinds and s u"mbanlls
rWltfcorridor and gra..,..tlars
I IIDlslin9ul~lutN.Surl ac.e I I lnd ;~tln9 uiAl\atN.Of
CJ'I,"ne'con'l'),'_1
IC"___<yOJ
Walltl'$ot.lru ot 50 1'/\1 Inllgn irlea nl Surf ac.>1 ~of
Signir.e.nc.Wallr So!.H'et <.1Mi Ol lota l now lo lal now
I III
Oearwll ltf 01_,1",plum.I I
flow not Of flow Ilklty IV'1l.\ll~INO_'9'lIl~IIlkety10bel"nul ltCld by u pper uppe rInnu.nc~by main,,:,,"...lIr tNtwlll tha lwigmainsl.m waler s.urtac••lw..tlonsurfl«1~lllon
I I
Surfacl ,,...Surfacl ..r,a
01 SidI Cf\annel oI lN1inSllm
I I h..bill1 hab illt
....~Surf ac •Sutl ac.Surface
.r,.o r ""of II.'of.r..01 trtlNllry upland 1'01.IrilNtary ~'"alo Ui".......tul bilJ,'"a bllat ha tKIal hab itat
A GURE 1 Key 10 aquatiC h ab illl classlfl~tJon tOt the Tal kee tna 10 Devil Ca n yon teach or the $ua ltna River.(RM 101 10 1U ).
-4-
photo mosai cs were su bd iv ided I nto e Ighteen sections of appr oxl .ately
the same l ength, with a s .al l a~nt of overlap between adjo in ing river
se cti ons. A s et of e igh teen 4-1/2 Inch by 15 I nch ph ot opl at es was
printed f or ea ch of the seven d lsch.-ges (Append ix O .For t he sets of
photogra phy taken at 23,000;18,000;16,000 ;a nd 12~00 cts,each photo
p late WOJ s carefully exami ned a nd areas t hat were t oo sm a l l In size to
prov I de deta II ed resol ut Ion wer e en lar ged t o a sca l e of 1 Inch ·25 0
feet.Al l s et s of ph otognll phy taken et 10 ,600 ;7 ,400,and 5,100 c fs,
were enlerged to e seat e of 1 I nch ·250 feet.
Hnb ttot Type BouodArles
Aquat ic ha bi t at boundar ies .apped o n the b lue l Ine pr in ts dur ing t he
he licopter reconnai ssance flights were trensf erred t o correspond i ng s e ts
of photogrephs. F igure 2 prov ides an e )Ulm p l e of th e technique used for
t he phot ogr ap hy ta ken at 23 ,00 0;18 ,000 ;16 ,COO;a nd 12 ,500 cfs.The
technique used for the photogrep:--y taken a t 10,600 ,7,400;and 5,100 c 15
was essentia lly t he same,with t he e xception that no enlargement a reas
were def Ined becau se t he ent I re set of ph ot ogrlllphy ves pr I nted lit t he
enllll rged sClllle of 1 :nch ·2 50 faet.A total a t 35 adj oin ing plates
were needed to co ver t he en t ire TalkaQtna-to-Dev ll Canyon reach at that
sca le.Matc hl loes were drewn on ad j o i n i ng photo plates to ensure t hat
habi tat areas wi th i n over lapp i ng secti ons near tha edge s a t the p lates
.ere not co un ted twice.The boundary of each e n largement area was
establ ished us ing prominent topograph ic features I n the photography and
drawn on bot h th e plate and t he In di vi dual en iarge lllent.Th is ensured
that areas within t he enlargement cou ld be summed a nd compared with the
e n largement area o n the p late.
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The externa l boundaries o f th e tota l er-ee t o be Inc luded In the s urf ace
area anal ys is (cont r o l a rea)were def I ned o n eac h p l at.,s o t hat s u b-
areas w ith I n t he c ont ro l ar ea c aul d be t ot a I ed and co mpared w ith th e
total con tro l area of that pl a te.In In eny cases ,It was nece Jury t o go
beyon d the river channel bounderles t o establ ish en Icent ltlab le con trol
MINI boundar y.The area t ocat ed betwe8n the control a rea boundary an d
the river channel was d l ~ltl zed as "background"(r-efer to Figure 2 b).
010 't1zl oo
I n t h is report,dig it iz ing refers to t he process of ca lcu l at ing the area
wlthln a per I met er c I rcu mscr l bed o n t he areal ph ot ogr aph s .Area
c a lcu lations were ma de usi ng a Numon l cs Mode l 2 400 Dl g l TllI b l et lin d
El e ctro nic Graphi cs Ca lcu lator conne cted to an Ep son HX -20 No tebook
Comput er.Pri or to d i g i t iz i ng e ac h phot o p late a nd enlar geme nt,
boundar ies we r e dr awn around ea ch wetted a nd non- wet t ed hab i tat el ement.
By tracing the per imeter o f a g i ven ar ea '1 1t h the Num onlcs Ol glTab l et
cursor ,~he area c i rc um scr ibed 15 ca lc ulated by t he Graphi cs Cal culator
to a n accurecy o f 0 .01 sq uare Inch.This accu racy 15 less t han th et o f
dellneetlon and operator t racing error.
Dig itiz ing strategy c ons Is ted o f d ig i t iz ing th e c ontro l area,the
e nl a rg emen ts (If pre sent )and elem ents w it hi n the c ont r ol are~If
enlarge ment s were present,the tota l arelll of the en iergelllent ~a s
d ig it ized and t he n t he e lement s wit h i n It. Eac h ar ea c alc ulat ion was
perf or.ad t.lce.If t he percent e rror betw een th e t wo measur ements was
greater t han five percent,the area was red l gl tlzed unt i l th e per cent
agreement was l ess tha n five.An I nte r ac tIve c omput er p rogra m was
FIGURE za .Example ot a Susitna Ri ver segment w i th habitat types m apped and c lass if i ed .
2b .Exam ple 01 t he s ame rlv ~r seg men t as delineated prior t o digitizing.
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developed for th e HX-2O,which pr ompted the dlg ltlz Ing ope r ator f or th e
pI ate number,f Io w code,c ont rol a r ea nu.ber,enl erg e. e nt nu . ber (If
en t ergeeen t ),enlargement fector,habi tat code,e leme nt number and t he
digi t ized area (tra nsf erred from the gr aphics cal culator).The progralll
ch ecked percent agreemeflt f or e ach meas.urement,a nd perfor med the
summntlon o f elame nt s for compar ison wi th t he Init i al con trol a rea
measurement.
pot a B§$@
Sur face area me as urement s that hed been stored on the Epson megnetl c
tape c essettes were trans fe rre d I nto a c omput er ized da t a base f or
storage,sorting,end SUbsequ ent anal ysl:..Eoch I ndivi dua l s urface ar ea
meas ureee nt was entered a s a se para te record that e04bled Identificat ion
by discharge,photograph (correspond ing to a river mile I ndex) ,a nd
In divid ual area num ber.
Correct ion factor s wer e e nt er ed to s t andardi ze t o a c ommon sc ale o f 1
I nc h·1000 f e et.Due t o prev ai ling weat her factors at the time the
aerial phot ography flights,slight vari ations In sc ale occ ur red I n th e
v ari ous p hoto s et s.Surface area s with in enlargement areas and for
those sets of photos printed Antlrely at the enlarged scale were d ivided
by a fector o f 16 to a ccount f or the fo urfold d ifference In scal e
between 1 Inc h ·250 feet <!Ind I Inc h .1000 feet.
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Surface a reas were s umm ed by heblt at type for the entire river corridor
bet ween Ta lke.tna an d Dev il Cany on for e ach of t he seve n d ischa rges.
Percentages of the total river s urface a rea r epresen ted by ee cn aquat ic
hab itat type were ca lcu lated for each of the s even discharges.
Becaus e the chang e I n surfece area of aqua t i c ha b itat Is a function of
dlscher-ge a nd c hannel geOflletry,the Talkeetne-to-Dev ll Cenyon reac h was
sub di vi ded I nto four segmen ts,ea ch possessing somewhet different
geolllorpholog ical c ha ra ct er ist Ic s.RM 101 t o 113 CT a lke etne-to-l ane
Creek)Is a re latively c hannel Ized se gment of th e midd le r iver with fe w
mid-channel vegetated Isl onds or gravel ba r s ;:few side channels branch
off frOIl the malnstem .RM 113 to 122 (l ane Creek-ta-Curry )Is a mor e
bra ided s ~llenf with IllIld -channel Islands and si de c hanne ls branc hing
frOID t he malnstelD.RM 122 to 138 (Curry-fa-Go ld Creek )Is a br a ided
segment wit h l orge mid-channel Is lands and grllvel ba rs.Nu merous s ide
channe l s bra nch o ff fr om the ma lnsfe m.RM 138 t o 14 9 (Go l d Cr eek- t o-
Dev il Canyon)15 a more channe lized segment wi t h s o me l arge side
channe ls br anching off from the ma i nsfelll.Tot al surface ar eas o f each
habitat type wit hin these segments were determ ined to focus attent ion on
th e d ivers ity of habi tat types and surface area responses among se gm enTS
'11th d ifferent morphologic ch ar acterlstlc~
Avera ge mont h I y d isch ar ges f or th e Su s It n8 R iver at Go l d Cr eek r ange
f rom 1,500 cfs In wlnfer to 28,000 cfs dur ing s ummerJ the ave rage a nnual
dischar ge Is 9 ,7 00 cfs (fig ure 'a).Sno wmelt runoff dur ing June and
e arly JUl y accompanied by glac ial melt and r ainfal l r unoff du ring July
30 .0 00..,..----------------,
25 .000
15 .00 0
RESULTS
type surface areas as a function of malnstem discharge for other
d ischarges was referenced to the digit ized surface areas on t he 23,000
cfs photography.
to dep ict baseline mid-summer conditions.The percent change In habit at
Canyon reach of the Susltna River.Therefore,th is photograp hy was used
From an analysis of the hydrologic data,It was determined that the
aer ial photography obtained at a malnstem discharge of 23,000 cfs
represents a typ Ica I mid-summer discharge for the Tal keetna-t~Dev I I
and August provide st~ble and persistent high summer discharges (FIgure
3b,c,dl.
r-,-f--
<,t-,
I I
I I
I I I.I I I I I
, ,I
I
JUNE.
B.
10
o 10 2 0 3 0 40 SO 60 7 0 80 90 100
¥II 01 Tim e Di s: harge Equall ed or Exceeded
10a
6
4
10'
a
6
10'a
6
..
u
"Ic
A SONDJFMAIAJ
Months
A.
Ave rage 1oI0nthly_
5,000
10 ,000
20 .000..
u
"i
~
is
C.D.
FIGURE 3 Average annual discharge and ave rage monthly d ischarges
for the Sus ltna River at Gold Creek (adapted from Scu lly,
Leveen ,and George 1978)j b ,c ,d .Monthly flow dura tion
curves for the Susitna River at Gold Creek (adapted from
Acres American Inc. 1983)..
s ide channel ha bi t at s decreased with decr~aslng d isc ha rge.
associated with specific geographical location and the habitat type
Surface area values presented I n Table 2 ~ere plotted to Illustrate the
surface area responses of indiv idual habitat types I n response t o
changes In ma I nste discharge (FIgure 4l.Surface areas of ma I nstem and
some cases,such as for tributaries and their mouths,habitat type Is
Canyon reach of the Susitna River are presented In Table 2.These
persists over a broad range of streamflows even though the surface areas
habitat types represent physical characteristics of the environment.In
may respond significantly to changes In dlscharg~In other Instances,
another as river stage Increases or decreases.
specific geographic locations transform from one habitat type Into
Total surface areas for aquatic habitat types I n the Talkeetna-t~Devl l
I
.......,,Ir.......-'I l'\
I
I
AUGUST.
10'
8
6
4
10'
8
6
10
o \0 20 30 40 SO 60 70 80 90 \00
¥II 01 Ti me Disc harge Equalled or Exceeded
10 '
3
6
..
u
"!i
~c
----'-
I
JULY.10
o 10 20 30 40 SO 60 70 ao 9C 100
~0'Ti m. Discharge Equalled or £acceded
10'
8
"6
4
10'a
6
10'a
6
..
u
e
!i
~c
-8-
PR OVIS IDNAl
E.Wooty Trihey £.AssocIat es
Date 1 ---'('t 5
Tabl e 2 .Tot~1 s ur face areas by h~bl Tat ty pe within the Ta l k ee tna-t~D8vll
Canyon reach of t he sustme River.
1 .500 r-.T""T""T""T""T'"T'"T'"T'"T'"............................,.....,..""T""T...
MAIN STEM
Surt ne'Ar"(ner,,1 by Q I lS b"rg'
HO b Itat Ty pe ,1 00 c 's :wJl!L<.t.o JO MQ c1$12 ,po C is 16 pop C is 18000 cts "pop cfs
Malns1.2 ",58 .t 2~99 .6 21lO5.9 2850 .4 3158 .5 '.3737.2i5
Si de Channel 729.7 768 .7 968.7 1095 .5 1222 .2
~1240 .7
"
Si de S Iou9h 121.4 144 .0 U C.2 118.1 .,.e -c '2.5>-e u ~upland Sl ough 1'.l 22.9 19.6 23.6 2 2 .6 .24 .4
'C;r-
~•Tr l buhry Mouth 15 .9 15 .1 18 .6 26.2 2'.':...12.1..-
Crave I Bor 2'18 .'23 01.2 18",8.4 1127.7 1419 .2 .,t:.,81 5.8,..
T ..:
Yege t . t e d Bar 1945 .4 2 130 .S 2 080 .2 1919 .1 2011.4 .""(.":..1718 .4
PRO VISIOIlAl
E.Wo ody Trihey &Ass ociates
Date 1-:0 -8 5
1,0 00
~....
~
"..-....
~
<..
"..-100~
"til
5 0
--....SIOE CHANNEL
PLANO SLOUGH
10 L.JL....JL....JL...I:....J-l-l-l.-l--l.--I.--I.....L.....L.....L.....L.....L...L...J....J
I>10 15
Maln.tem D ischarge at Gold Creek
F IGUR E 4
Su rface area responses to ma lns tem d ischa rge in the
Tatkeetna-tc-Devil Canyon reach 01 the susn ne n iver
(RM 101 '0 149).
-9 -
COnc ur rentl y, expo sed grave l ba r surface area Inc rUHd with deereased
disCharge .
SI de slough sur f a ce area Incre ased wi th deer"S I "g d I $Charge dow"to a
.a lnste_discharge o f 7 ,..00 efs, a nd then decreased at 5,1 00 cfs.
Upland sl Cou gh surface area reaalned rel atively constant av er th e range
of aa lnst.d i scharges,deCreasing so-ewnat a t 5 ,100 cfs.Surface a rea
of tr i butary IIOU th hab itat peaked a t I nt e r.eellat .flows of 16,000 and
12,500 ch.Vegetated bar surface area r ..a lned relati vely constant ovet'
the r ange of malnst ••d ischarges.
Ta ble 3 present s the percentage of th e total ri ver corri dOr repr esented
by each habi t at type for Bach o f t he S8ven ID alnste.d i schar ges.Tab l e"
pr e sen ts t he percent change I n t he s urf ace area of e ac h habi t at t ype
with de cr ea s ing d ischarge as c alc ulated f r om a bas eli ne d Isc harge of
2 3,000 cts.
Th& Ta l kee tna-to-OevII Canyon reach was di vided I nt o four segments based
upon differing geomor pholog ical c harac+er lst lcs.These s egments e xtend
from a pproxillat el y r iv er li lies <RM )101 t o 113 ,113 to 122, 122 to 138,
and 138 to "'9.aeeecse o f d I tferences I n the eeount o f sur fa ce a r ea
w it h i n e ach river se gll ent and the desire to accen t the r e sponse o f
habi t at su r face areas within t he ...Ivet" segmen ts,surface ar eas f or the
var ious habitat types ar e reported as the percent of total Mea In the
r lv'!lt'corr idor <Figu re 5 ).Figure 6 presents a rel a tive compa rison of
total surface areas c a lculated for var ious hab itat types with in t he
-10-
en ti re T alkee tn~t~evll Canyon r each and wit hin th e fou r se g _ent s In
res ponse to ch anging _alnst.di sch arge.
DISCUSSION
Air photo Inter pret a ti on Is highly dependent upon th e qu al ity of the
photogr aphy. Al though eec h se t ot photogr aphs obtaIned Ie<"tills study
was genera lly clear a nd complete,the t l ..of dey,da t e, and preva il ing
wea t her c on di t i ons at t he tl_e 'the aerial photograp h ic .I s sl ons w. re
flo wn affected th e extent to wh i ch deta i led river ine fe atures w. r e
vis ible.
The 23 ,000 c fs phot ograp hy,ta ke n on June 1,1 982,_a s ob tained at a
tl.e o f t he year when the su n was a t B high ang le and de c ld lou s
ve get at ion had not fU ll y lea fed -out. Thi s re s u lted In f ew shadO w$,
e nabl ing e xce llent del ineat ion of wat e r 's e dge a nd s lou gh ec uneer t es.
The 7,40 0 c f s and 5 ,100 cf s pho tograp hy,obtained on Octobe r 4 and 1",
1984,respectively,h8ve e xt ens ive areas of sh adows al ong t he s out h a nd
eest sh orelines.Thi s was due pr imarily to the l ow sun an gle dur ing
t hat t lllle o f year.These sh adows sometimes obscured the wa ter's edge
and made so me su r-t eee area delineations mere d i ff icul t.The rem aining
sets of photography had Isol ated shadow prObl8llls. In spite o f the minor
problems w it h ph otograph ic detail ,ac curate a nd r-et r eete s urface a rea
••asure.ents ~er.o bt a ined using various techniques to aid I n
del ineat ions.
Tabl e ).Surf ace areas by hab itat typ e within the Tel ke etna-To-Dev II
Canyo n r each o f th e Sus ltna River expressed as a percentage of
t he t otlSl r llfCf'COf"'r idor are a.
PeCCt o tcg.b y Q'Vb"CQft
Table 4.PercenT change In d l gl f l z ed surface areas relative to
corres ponding a r eas pre $e nt aT 23 ,000 c ts.
prrctltlt tlQft Cbl'lOCt'by O l ghOr p '
HOb I tot Ty po
Malnst "
Si d.Ch"tln el
S id .S l oug h
Up l and S lough
Tr l but ery Mouth
y.s-tate d Ber
5 l Op eta
31.5
I..
0 .2
0 .2
32.3
~
32.5
9 .6
I..
0 .3
0 .2
28 .8
26 .7
10600 e ft
.35 .6
12 .3
1 .7
0 .2
0 .2
2'.4
26 .4
'7 '00 e ta
36.7
14 .1
1 .5
0 .3
0 .3
22 .2
24.7
'6 QOO CIs
39 .7
15.c
18000 ct ,
~-:-c ~
r:-',..
i 4 ~
"OOQ cIs
49.1
16.3
0.7
0.3
0 .2
10.7
22.6
HelD I tnt Typo
S ide Channel
Side Slough
Up l and Sl ough
Tr i butary Mouth
Gr aYel Bar
e-
0;\.,0 ~..;~
;~;;
H e:
63.4
-1 ••
1(19.1
74 .0
12 ,PO c ts
-23 .7
"1 1.7
12 5.0
-3.3
116.5
11 1.8
1Q 600 C fs
-24 .9
-21 .9
1" .6
-19.7
'3.7
126 .b
-'0 .4 -3-4.2
-38.0 -41.2
174.3 131.2
-6.1 -37 .3
24.8 '1.4
1$2 .1 208 .1
PIl0VISlONAL
E.Woody Trlhey &Assoc iates
Date 1 ·...)(··e-:;
-11-
PRO \1SI0 IlAL
E.Wood'; Trlhey &Assxla tes
Date ::1 -;.r.•s ";
IlIA INSTEM
PROVISIO'!Al
E.WOOft/Trihey G Associates
Dale -I iX··f 'j
-.
(x'D e ta)
d
S IDE S L OUGH
5 1 a 15 2 0
M a l nste m D i s ch a rge a t G old Cr ••ll:
••
;: 2 0
c
•'0 SI DE
..'A
•~e o-e
••.:!50·,..
~40
"··•o .0
c•e•..-.h:,o c is)
b
2 0
Ma ln sl e m Dl ach ar ge .t Gold Cr.a k
a
••
<00
••~50,..
•U·•·or 2 0
••..10
c•S IDE SLO UO H•••10 ,...
"..In . ta m D h ch .,g ••t Gol d C r. ak
cis)
-.
htD
AI NSTEM
G RAVEL"BA R
S IDE C HA NNE L
5 1 0 1 5 2 0
Ma ln s'ftm D i s c h arg a a t Go ld Cr.a k
SIDE S LOUGH~•e•..
•~e o
<
•a
~SO
·••cr 2 0..
a..10
,..
~40
"·~
U
-.(x 1 0 eta)
2 0
SI CE SL OUG HI.
GRAV EL 'B AR
SIDE C H AN NEL
'0
•••00-e
••~SO,..
~-40
O?·•U .0·••
or 2 0..
;;..'a
~•u
••..
F igure 5.Su rface a rea responses to main stem di scharge expressed a s a p erc en tage o f
the tota l river c or r i do r surface a rea . Seqment a :Talk e etna -to -Lane Creek
(RM 101 to 1131,S eqment b :Lane Creex- t o- Cur r y (RM 11 3 to 122),Seqment c :
Curry -to-Gol d Creek (RM 122 t o 1 3 8);Segmen t d :Gold creek -t o -De v i l Can y on
IRM 138 to 14 9).
-12-
PIIOVlIIOIlAL
E.WOOIty Trlhey &Associa tes
Data '1 .'8£-c !i
23 .000
@D'
.:.:-:--.'..
@)'
:;:;::-.\..
~"I
··~~~l:...._.
18.00012.80010••0074008100
G~~'.
..~~,;
J:I:-:.'
:-:.:,'.
'';-.
(R M 12210 138 )
(RM 10 110 113 )
(RM l 13 10122)
(RM 101 to 149 )
Gol d C reek
10 ( R M 138 10 149 )
De vil C anyon
Curry
to
GoldCreek
Talkeetr:a
10
Lane C reek
La ne Cr eek
10
Curry
Talkeetna
to
Dev il Canyon
Vegetation
S ide S lough
LEGEND
o Upland Slough
o Tributary Mouth
1:-:-:-1 Gravel Bar
o Mainstem
m Sije Channel
F i gure 6 .A compar ison of rela t i ve amounts o f the d ifferent habitat t ypes c ompris ing v a riou s segments
o f the Susltna Ri ve r a t six ma instem d i scharge s.
-13-
Aquat ic habitat su rf ace Drea r es po nses are a fu nct ion of str88mf low en d
c h annel geolletry. Saa l l l oca l cha n ges wer e observed during t he tille
per iod I n which the sets of ph otogr aphy wer e ob t a ined.These s mal I
ch anges were thOugh t to have an In5lg nl flc,ant effect on the accuraCy of
the surface a r ea meas urements or the ,abil ity to .ake comparisons between
photographs taken I n diff eren t years.If channe l geo.etry re.alns
reiat iy ely con stant oyer t 11l8,then the a quat ic h ab itat surface a r ea
re sponses can a lso be expected t o rema in con stant.Thar£fore,the
results presented here are representatlYe of open e et er condit ions a nd
exist ing ch annel geometry.
The proposed project Is e xpected t o r esult In a longer ope n- water season
than Is present under natural cond it ions.I n add It ion , when f reeze-up
occ ur s,the l oc ati on of t he Ice f r ont 15 a nt ic ipat ed t o occur h r ther
downstrwall,leayln g portion s of the middle rlyer Ice-free (Harze-Ebasco
1985 •• b).
Some changes I n channel morphology are antic ipated.The ma'nstem
ch anne l 15 expec t e d t o d e grade by a s muc h a s a f o ot,leavi ng some si de
ch annel 8 nd s lo ugh ar eas perc hed.This would r e s ul t In a hIgher
ma lns t em stage requi red to o vertop the e l t u vle!berms (Harza-E ba s co
19850).
The surface eree response petterns presented here co ul d be ad justed to
acco unt for 811 tered breach I"g di scharge ,of ver-l o u&&Ioughs and 5 Ide
channel s an d, t her ef oro,be a pplicable to a post-project scenario.It
must be re-emphas lzed,ho wever,that the res u lts of this study make no
-14-
asseSSllent of the qua l i ty o f th e ha bita ts or the ir su itabi l ity for use
by fish.
Definitions for aq uat ic hab itat types used In this stUdy represent a set
of visually recogn iz abl e,strea_flow dependent phy sica l c ha racter isti cs
that do not r es tri ct the oc currence o f a par t iCUlar h a bi t a t type t o
f ixed geograph ica l locat ions.An e xamp le of tha fl ow-dependent ~at ur e
of t t.sa def in it i ons Is r ef l ect ed by s ide slough and s ide channel
habitats.S ide sloughs,by defin i tion,are clear wat er habi t ats I n
which the flow Is lIIalntalned by upwell ing and l ocal s urf ace ru noff.A
non-ve getated alluylal berm at the up s tream end of the dewatered
oyerflow ch an nel s ep arates the clear wat er ~a b l t a t fr om the act lye
Chan ne l.When lIIalns tem discharge Inc reases an d r-Iver stage rises .t he
alluv ial berm at the head o f the slough 15 cver t ocped,Turbid malnst em
wat er f lows Into t he c hannel and rep laces the for mer c lear water hab itat
wit h deepe r,f aster-flowing tu r bi d wat er. The aquat ic habitat at this
locat ion then f its the defi nition of s ide channel habitat.Conye rsely,
a s malnst em disch arge de c r ea s es, a reas class lf"td as side channels may
become cut of f from malnst em f low at the Ir upstream e nd and become clear
water habi tats.I f the clea r water I nf l ow t o t h ese sys tems Is
sufficient to maint ain a downstream con nec tion wi th t he mal nstem.these
areas then fi t the def in it ion o f s i de s lough hab itat.
General trend s I n s u rface area response to mal n stera discharge became
apparent I n this study.As .a l ns tem di s charge decreased,the s ur f ace
area of both mal nst em and side channel habitat t ypes de creased.
Concurrently,s Ide slough habi t at s ur faco area I ncr e ased wi th decreasing
d ischarge.The decrease I n s ide s lough surface a rea sh own e-t 5,100 cfs
was due to some of the sloughs dewatering at their downstream end
leaving remnant,ponded water which was not considered available
habitat.
The ~urface area response of malnstem,side channel,and side slough
habitat Is not necessarily directly correlated with habitat quality.In
malnstem and some sl :e channel habitats,velocity and depth are limiting
factors for the distribution of fish.As malnstem and side channel
surface areas decrease with decreasing malnstem stage,water depths and
velocities In these areas are reduced,making these habitats more
suItab Ie for use by fish.ConverseIy, as maInstem discharge decreases
and sIde slough habItat Incr eases,these aIready she II ow slough areas
may become even shallower with very low velocities.Access Into these
areas may become a problem and/or the shallow depths of the sloughs
themselves may result In less than suitable habitat.
Tributary mouths and upland sloughs are the other source of clear water
habitats In the middle river.Tributary mouth habitat surface area Is a
function of both malnstem discharge and tributary flow.Surface area
was low at a maI nstem discharge of 23,000 cfs,Incr eased at moderate
malnstem d ischarges and then decreased at discharges of 10,600 cfs and
below. At 23,000 cfs,the combination of high malnste..stage and water
velocities resulted In a shearing off of the clear water plume as It
entered the malnstem .The decrease In tributary mouth surface area at
the lower malnstem discharges probably reflects lower tributary flows .
Upland s lough surface area remained relatively constant over the range
of maI nstem discharges Invest !gated.At 5,100 cfs,the sur-race area
-15-
decrease was due to the mouths of some upland sloughs becoming dewatered
leaving the sloughs as remnant,ponded areas I naccessible to fish.
As malnstem discharge decreased,the combined surface area of clear
water habitats Increased.This Increase In clear water Is Import ant not
only as potential juvenile salmon rearing habitat,but could be of
I mportance for pr Imary and secondary product Ion If these c I ear water
areas remained relatively stabl~For example,a reduction In ma lnstem
discharge from 23,000 to 10,600 cfs (essentially halv ing the mid-summer
flow)results In a 200 percent Increase In tota l clear water s urface
area with a 50 percent decrease In turbid water surface area,and a 125
percent Increase In exposed gravel bars.Even a decrease In discharge
from 23,000 to 16,000 cfs results In a 170 percent Increase In clear
water,primarily due to Increased tributary mou th surface area.
It must be re-emphaslzed he re t hat an Increase I n clear water surface
area Is not directly correlated with a~Increase I n sui tab le fish
habitat.By defin it ion,side sloughs are clear water areas mainta ined
by upwelling.Without field verification,It I s diff icult to
distingu ish between true side sloughs and areas containing clear water
due to settling out of s uspended sed iments and poss ibly dilu tion by
surface water runoff once the upstream berm o f a s Ide c hanne l Is
dewatered.
Different segments of th e mIddIe Sus I tna River appear different
morphologically and vary In the relative amounts of wetted areas,gravel
bars,and vegetated Is lands.ina II segments,maI nstem a nd vegetated
Island surface areas predominate.The greatest diversity occurs In the
Lane Creek-to-Gold Creek segment (RM 113 to 138l,In which a greater
percentage of the total surface area Is represented by gravel and
vegetated bars.This river segment Is characterized by a more braided
channel pattern.In these areas,the relatively large edge effect due
to the numerous Islands and gravel bars may result In the potential for
creation of more usable habitat along channel margins and In channels
with higher streambed elevations as malnstem stage drops and water
velocities are reduced.In contrast,relatively steep-banked,
channelized segments of the rl ver where edge effects are minImal wIII
probably not show as large an Increase In potential habitat.
The results of this study can be used to Indicate the potential for
Increase or decrease In the amount of usable habitat by evaluating
surface area responses of various habitat types.The term usable
habitat would Include not only fish habitat,but also aquatic habitats
suitable for primary and secondary production.However,the I Imitations
of the surface area data generated by this study must be realized.
These I Imitations reflect the strictly physical descriptions of the
habItat ty pes def Ined here.
The results of this study,however,can be applied to both ongoing and
future additional studies which focus more directly on various
biological features of aquatic habitats.Habitat recon work (Aaserude,
et at,1985) focused on further defining and subdividing habitat types
Into categor Ies whIch more spec I flea IIy def Ine habItat attr Ibutes and
responses to flow. Fish utilization data (Hoffman 1985)will be applied
to the results of the habitat recon work to provide a measure of t he
-16-
suitability of the various aque t lc habitats for use by adult and
juven IIe sal mono
Measurements of primary production In the middle river are artlclpated
from AEID~This work, In combination with the development of a
euphot Ic surf ace area response mode I (Reub,et aI. 1985), wIII address
the issue of with-proJect pr Imary production potent IaI. These stud Ies
wll I provide biological significance to the Increase In total surface
area of clear water habitats seen In this study as malnstem discharge
decreased.
The surf ace area response data presented here represent a port Ion of a
much larger Integrated data base which,when complete,will facilitate
the forecasting of the effects of altered streamflows on the biological
and habitat components of the middle Susltna River.
Aaser ude, R.J .,J . Th i e l e,a nd O. Tr udgen.1985.~t .g od z at l on a nd
c ha racter izat ion o f aqua t ic h a bitat t ypes of t he mi ddl e Sus ltna
Ri ver.E.Wood y Tr lhey a nd A, soc la te s .Ancho ra ge,AK. Tech n i cal
Il.-orandum. , vet,
Aere s Aller le an In c .19 83.Susltna hydr oel ectric pro ject f ERC l icen se
appl i cat ion,Exh ib it E,Chapter 2, Anchoragtl,AA.
Alaska Department of f ish and Game, Susl tna Hydro Aquat ic Stud Ies.1983.
Phase II ea s t e data report.Yol.4l Aquat ic habi t at and I ns t r e a.
f low stUd ies,1982 .Anchorage,AX .Part 1 ,p.2.
Bredt hau er,5.,a nd 8.Drage.1982 .Alaska Po wer Author it y,sus r t ne
hydroe lectr ic project;task 3 -hydro logy;r iver IlOt"phology.F\&N
Consultants, Inc.,Anchorage,AA.RepClr't for Acre s Am e rl cen I nc.
Her-ae-Eeescc Susltna J o int Yenture.198'&.Roservo lr-r lver t emperdures
a nd Ice s imulations f or Wetana only operating In 2001.Volume 5,
Appe ndi x G.Report for Alaska Power Authorit y.Sus l t n a
Hydroe l ectr Ic Project.Document 2604.
______•198'b.Reservoir-river temperatures and Ice si mula ti ons tor Watena
and Dev i l Cenyon op erat ing In 2002 .Volu me 6 .Append ix H.Rep ort
t or Aleska Power Aut hor Ity. Susltna Hy dr oelect ri c Pr oject.Document
260~.
______•198'c.Nl ddle Sus l tna River Sed J llent at l on StUdy:Stream ch ennel
stab il ity a na lys is o f s e lected sl oughs.si de c ha nne ls a nd ma in
c hanne l l oca ti ons (Dr a ft ). Repo rt for Alaska Po wer Aut hor ity,
Anchorage,AK . I vet ,
R£F~R ENCf:S
-17-
Hoffean.A.198'.Tec hnl ca 're port.Su ••a r y of s al.on f i Shery data
c oll ected a t .I ddl e Sus lt na R iv er s ltes.(Dr aft).Sus .tna Hydro
Aquat ic Stud ies,Alaska Depar t.ent of f ish and Ga.e.1 vo r,
Kl inge r,S.1985. Ana l ys is of _I ddl .S u sltna River a e ri al ph ot o gr ap hy
and deter.lnat lon of aqua t ic habitat ty pe s ur-tece areas.E. Woody
Tr lhey and Assoc iates.Anchorage.AX..Technical memorandum..6 pp.
Kl inger.5•• and W.Trl hey.1984. Response o f a qua ti c hab i tat sur-t ece
areas t o lDa lnstem d Ischarge I n the Ta l keetn~to-De\'l l Canyon r each
o f th e Su s lt na Rlv .r,Ala ska.E.Wood y Trlhey and Assoc iates.
Report t or Alas ka Pover Au thor ity.Sus l tna Hy dr oelectri c Proje ct.
Docume nt 1693. 1 vo l.
Reub.G.,E.W.Tr lhey,and C. Wil k inson.1985.Pre l iminar y an a lys is of
t he I nf lu ence of a lter. d midd le river d isc har ge and t ur bid it y
r egi mes on the sur face ar ea of the euphot ic zone. E.Woody Tr lh ey
and Associates.Anchorage.AX..Technical meonorandum .I vel,
SCUlly,D.R.,l .S.La veen,and R. S.Geor ge.1978 . Sur t ece v ater record s
of Cook Inlet Basin ,Alaska.throug h S eptemb er 197'. U.S.
Geol 09 1<.>I Survey .AnchOt"age.IV<.Open-fi le Repor t 78- 498 .102 pp,
Appendix 1 .Plates.
MIDDLE SUSITNA RIVER
LEGENp
lAS MAINSTR EA M
5 C SI DE Cti AUNEL
!;S S ID E SLOUGH
US UPLAN D SLOUGH
T M TRI B UT ARY M OU TH
T T RI B U TARY
RIVER M i lE PLATE 1 OF 18 RIVERMilE 147 TO 149
ALASKA POWER AUTHORI TY
SU SrTNA H YDRO ELECTRIC PROJECT
EWT &A HARZA • :9A5CO
E.WOOOYTR!HEY susrrnAJOUlT vENTURE&ASSOCIA.TES
MIDD LE S USI TNA RIVER SUSIT NA HY DROELEC TRIC PROJECTusMAINSTREA M
SC S IDE CH ANrlE l
SS S IDE S LOUG H
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-------------------
MIDDLE SU SITNA RIVER
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SS SIDE SLO UGH
US U PL AIID SL OUGH
MIDD LE SUSITNA RIV ER
M S M AINSTREAM
S C SIDE CHANNEL
SS S IDE SLO UG H
U S UPLAND S LOU GH
T M TRI BUTARY MOU TH
T TRIBUT ARY
RI VER MIL E PLA TE 15 OF 18 RIVER MILE 10 8 T O 1 10
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P ROJ ECT
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SUSITNA JOINT VENTURE
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MS MA IN S TR EA M
SC SI DE CHANNEL
SS SID E SLOUGH
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T t.1 TRI BUTARY MOUT H
T TRIBUTARY
RIVE R MIL E PLATE 15 OF 18 RIVE.'l MILE 1 08 TO 110
EWT &:A
E.WOODY TRIHEY
&ASSOCIATES
M IDDLE SUSITNA RIVER
LEGEND
MS MAINSTR EAM
SC S ID E CHA NII E L
5 5 S IDE SL OUGH
US UP L AND S L OUGH
T M T R IBUTARY MOUTH
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R IVER MILE PLATE 16 OF 1 8 RIVER MILE 105 TO 107
ALASKA PO WER A UTHORITY
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&ASSOCIATES
MIDDLE SUSITNA RIVER
MS MAtrlSTREA M
SC SID E CH Atl NEL
SS SIDE S LOUG H
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T M TRIBUTARY M OUTH
T TRIBUTARY
RI VER MIL E PLATE 16 OF 18 RIVER MILE 105 TO 107
A LASKA POWER AUTHORITY
SUSITNA HY DROELECTRIC PROJECT
E \T &A
E.WOODYTRIHEY
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MIDDL E SUSITNA RIVER
M S M Al h STR E AM
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T M T RI BUTARY M O U T H
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M IDDLE SUSITNA RIVER
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TM T R IBU TAR Y MOU TH
T TRIBU T AR Y
RIVE R M IL E PLATE 16 OF 18 RIVER MILE 105 TO 107
ALASKA POWER AUTHORITY
SUSITNA HYDROE LECTRIC PROJECT
EWT &A
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ALASKA P OWER :'UTHORITY
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MIDDLE SUSITNA RI VER
PLATE 17 OF 18
T M T R IBUTARV M O UTH
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R IVER MILE
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SIDE SLOU GH
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LEGEND
l AS
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MIDDLE SUSITNA RIVER
MS M AINSTREAM
S C SIDE CHANNEL
SS SIDE SLOUGH
U S UPLAND SLOUGH
TT M TRIBUT ARY MOUTH
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+RIVER MILE PLATE 17 OF 18 RIVER MILE 1~2 TO 104
E.WOOD YTRIHEY
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HARZA -ESAS CO
SUSml AJOINTVENTU RE
MIDDLE SUSITNA RIVERLEGEND
M S MAINSTREAM
SC SIDE CHANN EL
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US UPLAND SLOUGH
T M TR IBUTARY MOU TH
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+RI VER M I LE PLATE 17 OF 1 8 RIVER MILE 10 2 T O 104
SUS ITNA
E WT & A
E.WOODYTRIHEY
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HA.-E8AS:0
SUSrTNAJOINT VENTURE
M S MAINSTRE AM
SC SIDE CHANNel
S S SIDE SLOUGH
US UPLAND SLOUGH
TM TRIBUTARY MOUTH
T TR IBUTARY
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EWT&A
E.WOODY TRIHEY
to ASSOCIATES
HARZA -=3ASC
SUSITNA.DNT VENTURE
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MIDDLE SUSITNA RIVER ALASKA POWER AUTHORITY
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LEGENU
MS MA IN ST R EAM
SC SIDE CH ANNEL
SS S I D E SL OUG H
US U PLAND SL OUGH
T M TRIBUTARY M OUTH
T TRIBUT ARY
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EWT&A
E.WOODYTRIHEY
&ASSOCIATES
HARZA -EBAS ",O
SUSITNA JOINTVEtrnJRE
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SUS ITNA HYDROELEC TRIC PROJECT
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EWT&A
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RIVER MILE 101 TO 102PLATE18OF18
T M TRIBUTARY MOU TH
T TRIBUTARY
R I VER MILE
MS MAINSTREAM
SC SlOE CHANNEL
SS SlOE SLOUGH
US UPLAN D SLOUGH
MI DDLE SUSITNA RIVER
M S M AIN STRE AM
SC SIDE C H ANNEL
SS SlOE SLOUGH
US U PLANO SLOUGH
T M T R I BU TARY M OU TH
T T R I BUTARY
RIV ER M ILE PLATE 1 8 OF 18 RIVER L'ILE 101 TO 1 0 2
E W T&A
E.WOODy m lHEY
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PROJECT
HARZA • EBAS C O
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