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HomeMy WebLinkAboutSUS444A •aeftfe IIfrCN8CT WA aALAttCE aTUBIla OF IIIDDLE SUSI-TNA SLOUGHS I JAM 151985 ~1lIpt.af"""..,..I4¥*' m 1425 .sa .472 80.27454 I R20 /1 1 •I •WATE R •I ••••••••·•••, •,.. SUSITNA H YDROELECTRIC PROJECT BALANCE STUDIE S OF MIDDLE SUSITNA SLO UGHS Re po rt By : RtM Co nsulta n ts,In c . P re p ared By: D ave Bje rk lie Stephe n Br edt haue r Bob But era Un der Co ntra ct t o : Haru Ebasco S usitn a J oint Vent ure Prep a red For : Alask a Power Aut hority D rilft Rep ort Decemb er 1984 I •••••••••,•••••I I I -_._------- - ------ -----..., R20/1 3 T ABLE OF CONTENTS PAGE NO . List o f Ta bles ii List o f F igu res iii Aeknowl e dgments tv 1.0 S umma ry 1· 1 2 .0 In t rodu ct ioo 2·1 3 .0 Desc rip tion o f Basi ns 3 -1 3.1 Sl o ugh 8 A 3 -1 3 .2 Slough 9 3 -2 3 .3 Slo ugh 11 3 -3 4 .0 1984 Data Collect ion 4 -1 4 .1 Streamflow 4 -1 4 .2 Precip itati on 4-1 4 .3 Eva poration 4-2 4 .4 G roundwater Levels 4 -2 4 .5 Aquifer P rope rties 4 -2 5 .0 Anal yses 5 ·1 5 .1 Precip itation 5 ·1 5 .2 Ma in stem -S loug h Dis chargo Relati onships 5 -2 5 .3 Storm Run off 5 -3 5 .4 Wa t er Balan ce 5 -4 6 .0 Conclusions 6 -1 7.0 Bib liograph y 7 -1 - R20/1 4 Table Number 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 LIST OF TABLES Description Mean Daily Flow,Slough 8A -1984 Mean Daily Flow,Slough 9 -1984 Mean Daily Flow,Upper Site,Tributary B, Slough 9 -1984 Mean Daily Flow,Lower Site,Tributary B, Slough 9 -1984 Mean Daily Flow,Slough 11 -1984 Footnotes for Slough Discha rge Data Mean Daily Flow,Susitna River at Gold Creek (June -October 1984) Middle Susitna Precipitation Gages Middle Susitna River,1984 Precipitation Data Evaporation Data,Watana Camp,1984 Falling Head Test Results,Slough 9 Boreholes 1984 Geographic Distribution of Precipitation, Middle Susitna River Monthly Precipitation Totals,Middle Susitna River Storm-Specific Precipitation Totals Precipitation Coefficients for Transfer of Recorded Data Regression Equations for Slough Discharge vs.Mainstem Discharge Storm Runoff Analyses,Slough 9 Tributary Monthly Water Balance,Sloughs 8A and 11 Monthly Water Balance,Slough 9,Tributary 9B II Page 4-3 4-4 4-5 4-6 4-7 4-8 4-9 4-10 4-11 4-18 4-19 5-7 5-8 5-9 5-10 5-11 5-12 5-13 5-14 R20/1 5 3 .1 3 .2 3 .3 3.4 ,.I 5 .1 5 .2 5 .3 5.4 5 .5 5 .6 5 .t 5 .8 LIST OF FIGURES D.,eription Middle Susl tna River S lough SA S lough 9 Slough 11 Groundwa ter level v s .Main stem Flow , Sl ough 9 Monthly Rainfall Exceedance C urves , Talkeetna ,Alas ka Pr ~ipitat i on Ex c eedan ce Curves ,J une , Talkeetna ,Alaska Preclpitattcn Exceedance Cu rves ,July , Talkeetna ,Alaska Precipitat ion Ex eeedan ce Curves ,August , Talkeetna ,Alaska Precipitation E xeeedance Cur ve s ,Sept ember , Ta lkeetna ,Alaska linear Regress ion Curves ,S lough Discharge v s .Mainstetr.Discharge l og Transformed Regressi on C urves ,Slough Dischargll vs .Mainstem Discharge S lough 9 S treamflow Patterns ,1984 ii i 3·' 3 ·5 3-6 3-' 4 ·20 5-15 5-16 5-17 5-18 5-19 5·20 5·21 5·22 - - - - R20/1 6 ACKNOWLEDGMENTS The 1984 data in this report were collected,reduced and analyzed by R&M Consultants under contract to Harza-Ebasco Susitna Joint Venture as part of the Susitna Hydroelectric Project,a project of the Alaska Power Authority. This report was authored by Dave Bjerklie,Stephen Bredthauer,and Bob Butera of R&M Consultants,I nco Review was provided by Don Beaver of Envirosphere Company.Field work was accomplished by Bill Ashton,Dave Bjerklie and Bob Butera.The Alaska Department of Fish and Game -Su Hydro is also acknowledged for the use of their field camp,monitoring of precipitation data and assistance with data collection. iv R201l 2 1.0 S UMMAR Y Groundwa te r disc harge i nto s lo ug hs aro ng t he Middle S usit na Rive r ma i n- t ains habi t at for sa lmon spawnin g a nd rea ring o f the juvenile sa lmon .T he opera tion of the proposed S usit na Hydroelect ric Project u ps tream of th ese areas would chi'nge t he f low r eg ime in t he rive r .Th e e ff ects o f th ese changes i n f low r egime o n t he g roun dw ater disch arge i nto th e s loug hs we re studied . A na lysis o f pre Viousl y c ollected data en d r-a in fa ll -r-u n o ff data collected during 1984 lead to t he followin g co ncl us ions : l .S ta ge <::h a n g l"S in the ma in stem wil l effect the r-ate of groundwate r- upwelli ng to t he sloughs .T he effect v ar ies fr-om sl oug h to s lo ugh bein g depen dent o n loca l st r-atig r-a phy .gr-adie nt.a nd s lough mor-phology .Re lationships h ave been deve loped f o r-S lo u g h s SA .9 a nd 11. 2 .Upla nd grou ndwa ter-i s a sig nifican t s our-ce o f wate r-to som e s lo u g hs . This a lso va r-ies between sloug hs .T he avai lability of t his water-to the sloughs d epe nds upon t hat po r-tion o f t he water-shed ar-ea wh ich h as deepe r-s o ils .preve ntin g r-a pid runoff .The ele vatten of the gr-o undwate r-tab le adjace nt t o t he s loughs is co n t roll ed by mainstern stage . 3.A h i gh per-centage o f precipitation r-uns o ff t he steep r-ock y hi l lslopes . Howeve r ,some o f t he water-seeps i nto th e ground as th e streams c ross a llu vial fans at t he base o f the s lopes ,r educing wate r avai lab le t o the s loug hs . ,-, -til...... •••••~ R20/1 7 2 .0 I NTRODUCT ION On the S usit n a River,side stoughs are def ined by the Alnka Depa rtme nt of F ish and Game IAO Ft.Gl as the s idechannel or adjacent wetted hab itats to the mOlinsteon SUl l tna Ri v er which periodi ca lly receive <II portion o f their sur-he.""'Oiter f rom the mainstem Susitn..River in a ddition to other s.ou rces .B et ween r.lkeetno:and De vil Can y on ,a n are..referred to on t he middle S usitn. River,the,--ex ist <II nu mber o f neas th at meet the a bove defini tion .Some o f these doug hs provide spoly-ni"g and o\'erwintering habitat for chum,pink lind sockeye sa lmon .For the y elrs 193 1-83 the est im.ted tctel numb er o f thes e spec ies u sing these sloughs f or spawn ing are .n f ollows :1,000 -2.000 Soc keye ;J,ooo - 5 ,000 Chum ;300 - 500 Pi nks(1). Th e major ch Oi r a cteri5tic o f th el e l lo ughl whi ch makel them l uita ble h abitat for $.lImon l p awn i ng and the o v e rwinte rin g o f $.lImon f ry il th'!y ear round f low o f wat'!r ,e ither U lurlac e o r in tragrav el flo w .T he lOUre el o f th il flow a nd the manner in wh ich it wo uld be affected b y the regulat ion of fl ow in the S Ul it na River ha ve bee n the focul of lt u die l th at have been in progren st ece 1982 .Previoul ly publilhed r e portl include Ac rel Amer ican (1983).R&M Co n l ui ta nh (1982) .and Alaska Power Auth orit y (1984). The purpose o f thi l report il to pres ent both 1984 data a nd additiona l an a lYl es o f th e h yd rolog i c conditions a t se lect ed s loughs in the middle Su sltna R iver .To further r efine previou s es timate'o f g roundwater flow i n to S lough 9 ,f alling head tes tl were con duct ed at t hrM we lls.Water le v els were a lso co ntinuou sly monitored at two wells .Instead of further attem pti ng to sepante the loc al and main stem c.xnponentl ot groundwater flo w into S lough 9 ,an attempt was made to d i rectly measure the flow which the uplands contributed to the s lo ugh .Add itiona l streamgagf'S a nd p re- c ipitation g ages were insta lled at a nd n ear Slough 9 i n orde r to co n duc t I wate r ba lance study .In additio n ,streamgages we re maintained o n S lou ghs SA an d 11 to «'nt i nue to document flow o n s lou ghs whic h rar"ly receive mainstem flow . 2 -1 --.---~._-- R20/1 8 3 .0 DESCR IPT ION OF BAS INS The follow ing ba sm d es c rip tions are mod ified s lig h tly from those by ADF &G • Su Hyd ro . 3 .1 S lo ug h 8A •RM 125 .3 S loug h SA i s loc ated o n the east ban k o f t he S us itna Riv er (Figu rl!'s 3 .1,3 .2).The s lou gh is app rollima te ly t wo mile s i n le n gt h a nd is s epa rated f rom t he ma ins tem S usit na Rive r by a large vege tated g rave l b ar .The sl ou gh mout h is adja ce nt t o a side c han ne l .Tw o pri ncipa l c ha nn els co n nec t t he sloug h w ith t he ma in stem S usi tna Rive r .The slo ug h c han nel i s relatively H ra ig ht w ith a ge nt le bend n ear the h e a d o f th e s loug h .App rOllimately 2 .000 f e et u p at reem o f th e mouth ,a s eries of b eaver d ams wh ich i nhi b it u pstream mig r atio n o f salmon are located ac r oss t he b raided c han nel.Some d ams a re compl etely filled i n with cobb le,r esu lt ing in a s e mi-pe rm ..ne nt ba r r ie r ,while o the rs ..ee f req ue nt ly mod ified by stage c ha nges . During th e 1983 se ason ,an o th er b ea ver d ..m was (C ons truct ed ..p pro ltima te ly 3 .200 feet up st ream of t he mo ut h .The bank s r an ge f r om lo w ,gent ly slopi ng b an ks to f iv e -foot h i9h s teep c ut b anks .The AI..ska Railr oa d p a rall els t he so ut h b ..nk o f the sloug h .The ov er ..11 s loug h gra die nt is 10 .5 f e et/mi le .Cobb le /bo u lde r subs tr at e pred o;omi n ate s in t he u pp er h ..lf o f the sl oug h .Gravel/r ubble is the pred ominant su b st ea te in th e lower half o f t he st ou gh .S ilt /sand d epo sits a re fo u nd int th e b ..ckwater are ..a t t he mouth and in the pot .l s f o..med b y the b ea ve r-d ams . A b ac kw..te r area e xte nds a pp rolt im..te ly 1 .000 f eet u pstream o f the mouth d u ring peri ods o f mod er t:t e t o)h igh ma in stem d is charge .Above th e b ..c kwetee a rea is a 100 -300 foo t r iffle fo llo wed b y a large beaver da m .The n orthwest ove rflow c ha n ne l f lows i n to a ta r ge p oo l beh ind th e bea v er d am.An other d ..m 1 ,200 feet fu rthe r upstream impo unds th e wate r from thl"no rt he ..s t c han n e l .The c o nt rolling d is charge of the n o ..thwest c han ne l is 27 ,000 c h ,while that o f t he n ortheast 3 ·' R2011 9 channel is appro.im.1ltely 33 ,000 c is.Bn.slough fl ow i s maintained by surlKe runoff ,groundwater s eepa ge Ind u pwelling .Rap id runoff occurs from the steep,rocky slopes adjacen t t o t h e sl ou gh . 3 .2 Slough 9 -RM 128.3 Slo ugh 9 i s a 1 .2 mile long unob structed "S"-shap :,:!c ha nn el o n t he s outh b.ln k of the S us i tna R i....e r-(Fi 9ures 3 .1.3 .3 ).Bo th the he..d ..nd mouth of t he s lo ug h o pen i n to si de ch in nels o f the m.1I in stem S us itn..Ri....er ,T he lower h ..lf of th e s lo ug h h n ..r et ..t i v el y sh..llow g rad ient wh ich steepe ns pnt a po i nt roug hly 3 ,000 f e et up s tream o f the mouth wh ere th e s lo ug h make s ..sh arp b end.T he o verall s lou gh g radient is 13 .7 f ee t/mil e .G r eve l/rubb le s ub s tr a t e is predom inant in t he low er ha lf o f the s lo ugh.wh ile cobble /boulde r predominates in t he up per h alf .Sil t/s..n d depos its a re f o und in th e pool a re as and th e b ac kwater a re..a t t he mouth .The area ..t th e mout h co n sists of sa nd b a rs th at a re i n a co n sbnt state o f c h..n ge .T he ban ks g ener..ll y h a v e a mod e rate t o s teep s lope and a re 3 -4 feet high.A s mall s lough (98 )br..nc hes off in a northe..sterly direction n e ar the h e ..d of S~U9 h 9 .The Aluk..Rai lroad pa rallel s t he southeast bn k of t he lower h..lf u f the s lough . The head o f th e s lough hn a n in it ial bre..c i·!ng discharge o f 16 .0Cl0 efs .Be low th is d is chlrge th e upper hal f o f t he slou gh is p ";rrulI..ly d ~,w ith ..n i n tr..g r ......e l fl ow o f wa t er .Th.,..i s li ttle,if ..n y , i n trag r ave l flo w i n t he lower h alf o f the s lo ugh.A t controlling di s ch lrge con diti o ns o f 19 ,000 c is o r ..bcve ,water fl ows f reely th rough t he s loug h,<:hilnging it t o a <:om pletely turb id e nvi ronment. At ma instem d ischil rg es less than 12.000 cis t he b lckwater area It the mouth utends 500 f e et upstre..m to the bne of the first riffle .At th e high ma instem di s ch..rges ,the r iffles ilre inundlted and the lowe r hillf o f the s lough becomes o ne long pool.The lower h..lf of the sl ough i s ..ser ies of poo ls ..nd r iffles e nding with the b..c kwater area 3-' -:;;, R20/1 10 at the mouth.Base slough flow is maintained by two small creeks and contributions from grou ndwater percolation (upwell i ng).The upstream creek was gaged at 2 locations in 1984.The creek origi- nates at a small lake at elevation 1900 feet,draining the steep upland areas before becoming ponded on the uphill side of the railroad tracks and meeting another small drainage.After flowing through culverts under the railbed,the creek flows through a meadow into Slough 9. The stream is occasionally dammed by beavers both upstream of the railroad tracks and between the tracks and Slough 9.Contributions to base slough flow by Slough 9B are negligible.A beaver dam was constructed across the mouth of Slough 9B in early 1983. 3.3 Slough 11 -RM 135.3 Slough 11 is approximately one mile long and is located on the east bank of the Susitna River (Figures 3.1,3.4).Both the head and the mouth of the slough join side channels of the mainstem Susitna River. The slough has a winding channel that is a series of pools and riffles with an overall gradient of 19.8 feet/mile.Substrate in the upper half of the slough is composed mostly of cobble/boulder with the lower half composed of gravel!rubble.Si It/sand deposits are confi ned mostly to the backwater pool at the mouth.This pool is formed by a relatively stable sand/gravel bar at the mouth.The slough channel is broad in general,being enlarged by dramatic breakups which occurred in previous years.The steep banks are approximately six feet high and sparsely vegetated. Slough 11 has a breaching discharge of approximately 42,000 cfs. The slough was last breached in June 1984.In an unbreached state, intragravel flow can be observed entering the slough through the berm at the head.However,this flow is minimal,and below breaching discharges most of the upper third of the slough is dewatered with isolated shallow pools.Su rface ru noff and upwell ing 3-3 R20/1 11 maintain jlow in the lower two-thirds of the slough.The backwater pool at the mouth exhibits considerable fluctuation in direct response to changes in mainstem discharge.The backwater area is quite broad, encompassing the entire slough width,in contrast to the narrow channel in the rest of the slough. 3-4 ~".-._...---_._---------- IG'· 10 SL OU ::i H 21 :l1 :"::S (.-U'?1to:<.SCAL::::) o ~£~ ~\I,,:~~"<,\SLOUGH 9 t?J\~$L OU GH eA ~ ~ ~~ loIAPAR£A ,. MODIFIED FRO}!Anne (2 ) I.LOC.\!I O::S or ?R I::C I !'.\L s t oecn srra...5r;:S .t '?S:!-1 9 S). • • SOl,.'R CE : •............ II II II II II II II II II II II III 1I II .....:.;:'....:..::.1 IOIfl,M CCN SU..TANT S .,N C .-----_._-Figure 3.1 s .~,,......:l.'""f "r ,,~1 < CD % <:I :::>o ..J...., '""~ "..;;: oo •o•u ," <l0 ( .. :~:,. /1'--"--'~, l..:. 0 '; " j "~; '::.: ::-', "', , ~':.~,;;:\'".~-"""~:,...., , ; -:.:. \'"-- ",-::-:-'f ~ "r .~, ©@@ •,~5-•I§=,-"--,I!'!J >-e.-->•z,•,-••~~~"0 -,•,••-~~~•>-•-••-,•~L?S ;;; 0 --•••-!~0••~Q I ,= Q ...= u: Z '., ,;1...Zi<~l ".,un ~.2 ! .'.O .;;J ......u:'I'".:..~~~I'w ,..... "'~-1·n "' -"•~ ~• "~ :. ..•.,.. • .. •,,,...c,IIIIIIIIII II II III III III III III III III III ~ /I ~ %e :::>o... CIl..•.... II: :::>e-... <]0 o 3-8 ., \ ••• •~• t-. -• ••••••••••••••••II II II R20 /1 12 4 .0 1984 DATA COLLECT ION 4 .1 St,....,..fkM' Fi ve s t re am gaging s tations were establ ished to defin e the flow chu- ac teristies o n 3 s lo ug hs .Th r-ee o f these s t ations were in S loug hs 8A , 9 and 11,a nd t wo we re locat ed o n a ma jor tr ibutary s t rea m t o S loug h 9 .Gagi ng locations a re s hown o n Figures 3 .2 .3 .3 .nd 3 .4 .Av er- .ge d . ily di scholrges .t e.c h s ite are toIbu l.ted if'l T.bles 4 .1 th rou gh 4 .5 with f oot f'l ot es if'l T abl e 4 .6 .All g.ge s ites co f'l sist ed of •still if'lg well and •Il eat-cper-e ted Ste vens T ypllt F r e corder.R.t ing c u rves were d eveloped e t e .ch site t o relate the re te of fl ow t o th e menured stage .B iweekl y s ervic ing o f these g .ges atlc wed 8 -1 0 discholrg e measurem ents to b e ma de at ea ch si te .At o ne s ite ,the g age o n the upper p.rt o f th e s lo ug h 9 tr ibutary ,•we ir wn i ns t a lled t o .!Iow e ee ueete mea suremen t of t he fl ow i n a n .re.wh ere no su itol bte n.turoll co n tro ls ui st ed .Prior t o Aug ust 13 ,1984 .th is wu •90"V-notch ....ei r .After t h is d ..te •su pp re$S ed rectol ngu l..r ....e ir w ith a crest len gth o f 1 .97 fee t wu used . P rov is ion..'me..n d.ily flow d ..t ..fo r t he Sus itna Rive r .t Gol d C r ~k are included 011 Table 4 .1 4 .2 Precip itation At the beg in nin g of t he 1984 f ie ld senon th ere ....e re th r ~we .ther s ta tio ns in the middle S us it n.Riv er b as in ,i nclud in g the T.tkeetna NOAA s tation a nd the Devil C anyon a nd S he rman S tations from the S usitna Hydroele ctric Project .The Devil Ca nyon s ite hn provided prec ipitolti on d a ti f or the summer months s ince 1981 .The S herm..n site wu installed in May 1982 .Howev er,th e precipita ~ion rec order at th is site worked onl y intermi tt ently from mid-Augu st 1983 to August 2 1,1984 ,wh en the s ite "NilIS repa ired .For mo re s tte - 4-1 4 .4 Groundwlter lev. " 4 .5 Aqu if er Properties 4 .3 Evaporation specific;dilt••f ive add ition.1 rOl in gages we,...installed i n the bui" in 1984.These sites Ire described in Table 4 .8 . --- -_.._._.--- ------- Pan evapontio"dau were gathe red at w..t.".Cam p .T he dilily an d monthly va lues &rill tabulated in T able 4 .9 . Flu c tuations in the groundwate r tab!e were meilS u red co nti nllous ly at t wo s ites i n t he S lo ug h 9 area .Bor ehol es were i ns trument ed with p re ssure t rans du c er s c o nnec t ed t o Omnid.h Data pod r ecced er-e , Flu ctuations i n g roundwater levels I re p lotted with mainstem disc ha rge olI t Gold C reeK o n F igure s 4 .1 (a)•4 .1 ld). R20/1 13•••••••, ••• Aquifer proper1:ies in the areas near the sloughs have not prevtously been well·defined .An .ttempt was tn4de to conduct a ris ing head pump test at Well 9 -1 It Slough 9 .Howey.r ,the test wn not sec - eessful i n provid ing uubl.d.till wi th wh ich to es:imilte aqu ife r prop ~ erties .Subsequentl y,blling hud tests w.....milld,at well si tes 9 -1 . 9 -2.9-3 .nd 9 -4.The dilltil were .nalylltd using t he tec h nique deser ibN by COOPe r ,Brede hoeft ,iIInd Pilpildopulos (1961).T he ~s ulting t rillnsmissiy ity y"lues determined from the d.t.ili A t .bu lilt ed i n r"ble 4 .10 . 4-' T ABLE 4 .1 MEAN DAILY FLOW .SLOUGH SA locil tion :Gage was midway a long t he leng th of s lough SA . Oro ain age Arn :1.51 s q .mi. Disc ha rge,;,Cubic Feet Per Second ,1984 Mea n Values D.y Jul y August s.ptembe,.October 1 5 .''.1 1.4 2 5 .G 3 .2 I., 3 2 .G 5 .2 2 .G 1.3•2 .G '.8 2 .'1.3 5 2 .''.8 2 .0 1.2 G 2 .2 •••1.7 1.1 7 2 .2 '.1 1.5 1.0 8 2 .0 3 .8 I..1.0s2.0 ,.4 1.2 1.0 10 2 .2 '.1 1.2 0 .' 11 2 .0 3 .G 1.0 0 .' 12 2 .2 3 .2 1.0 0 .8 13 2 .0 2.G 1.0 0 .7 14 2 .0 2.'0 .'O.G 15 1.7 2.2 0 .8 O.G l G 1.5 2.0 0 .'0 .5 17 1.2 1.7 0 .'0 .' 18 1.5 2.G 1.2 0 .' 19 1.7 •.I 1.7 0 .3 20 2 .2 '.8 2.2 0 .3 21 2.2 5.2 2.2 0 .3 22 2 .2 5.'2.2 0 .3 23 2 .2 8 .0 2.2 0.' 24 2.2 34.0 2.0 0 .3 25 2 .G £i5 .0 2.0 0 .3 2G •••44 .0 1.7 0 .3 27 5.G 17 .0 1.5 0 .2 28 7.1 11.0 1.5 0 .1 29 G.2 8 .0 I.,0 .1 30 8 .'5.'I.,0 .1 3 1 7.1 '.8 0 .1 • R20t l 14 TOT AL Mean M.. Mi n .... 2 .98 8 .' 1.2 285 9 .19 G5 1.7 '-3 51.0 1.70 '.1o.a 19 .6 0 .63 1.4 0 .1 ••.til R20/1 15 til II TABLE 4.2 MEAN DAILY FLOW.SLOUGH 9 II L ccat jcn :Downstream e nd of S lough 9 Drainage Area :2 .26 s q .mi. II D isch,l l"ge .in C ubic Feet Per Second ,1984 Me,n V. l ue, D.y June Jul y August S eptember October II 1 9 .1 190 190 18 2 .1 2 11 240 130 14 2.1 3 9 .7 21 0 66 11 2 .1 4 1 1(,1 )92 56 '.5 2 .0 5 11 66 69 7.1 2 .0 6 12 65 160 5 .6 1.9 7 18 sa 170 4 .8 1.9 8 23 55 150 4 .2 1.9 9 30 53 220 3 .6 1.9 10 35 51 200 3 .2 1.8 11 30 81 160 2 .8 1.8 12 29 62 50 2 .4 1.7 13 140 "40 2.4 1.6 14 500 51 24 2 .1 1.6 15 440 28 17 2 .1 1.6 16 810 20 14 2 .1 1.5 17 "13 2 .1 1.6 18 60 18 2 .7 1.4 19 ss 34 3 .2 1.4 20 sz 43 3 .6 1.4 21 70 56 4 .2 1.3 22 32 100 "3 .6 1.4 23 34 11 0 43 3 .2 1.4 24 44 57 300 2 .8 1.4 25 59 11 0 790 3 .3 1.4 (8) 26 140 590 750 3 .3 1 .4 (e ) 27 so 680 480 2 .8 1 .3(e) 28 27 500 160 2 .4 1 .3 (e ) 29 45 410 "2.4 1 .3(e) 30 65 380 35 2 .1 1 .3(e) 31 260 25 1 .3(e) T OTAL 4 .8~4 ,567 136 50 .1 M eal .156 147 4 .53 1.62 M"680 790 18 2 .1 Min 9 .1 20 13 2 .1 1.3 (.)Th e berm a t t he upstream e nd of S lough 9 w as ov ertop ped co ntin u· o U$ly b etween J une 4 t hrough Augu st 15 "d August 19 through Aug ust 30 . (,)Es timated v alues . 4-4 R20/1 16 TABLE 4.3 MEAN DAILY FLOW UPPER SITE,TRIBUTARY B,SLOUGH 9 Location:Gage was 150 feet uphill from the Railroad tracks on the tributary stream Drainage Area:0.73 sq.mi. Discharge,in Cubic Feet Per Second,1984 Mean Values Day August September October 1 0.92 1.89 0.80 2 1.02 1.59 0.75 3 1.03 1.48 0.75 4 1.02 1.26 0.75 5 1.08 1.15 0.71 6 1.11 1.10 0.66 7 0.95 0.99 0.66 8 0.85 0.94 0.66 9 1.14 0.90 0.66 10 1.03 0.84 0.66 11 0.92 0.75 0.66 12 0.82 0.75 0.62 13 0.73 0.78 0.62 14 0.71 0.73 0.57 15 0.71 0.69 0.53 16 0.62 0.66 0.49 17 0.57 0.66 0.49 18 0.85 0.80 0.45 19 1.89 0.88 0.45 20 2.27 1.10 0.41 21 2.20 1.07 0.38 22 2.53 1.04 0.41 23 3.07 1.02 0.38 24 8.89 0.97 0.38 25 14.7 0.97 0.34 26 9.91 0.90 0.30 27 6.23 0.90 0.27 28 4.74 0.85 0.24 29 3.42 0.85 0.20 30 2.79 0.85 0.18 31 2.33 0.18 TOTAL 81 .1 29.4 15.6 Mean 2.62 0.98 0.50 Max 14.7 1.89 0.80 Min 0.57 0.66 0.18 CFSM 3.59 1.34 0.68 IN 4.13 1.50 0.80 4-5 R20/1 17 TABLE 4.4 MEAN DAILY FLOW LOWER SITE,TRIBUTARY 8,SLOUGH 9 Location:Gage was 400 feet upstream of the mouth of the tributary stream. Drainage Area:1.46 sq.mi. Discharge,in Cubic Feet Per Second,1984 Mean Values Day June July August September October 1 2.2 1.5 1.7 1.9 0.09 2 2.7 1.4 2.4 1.4 0.09 3 2.4 1.4 1.7 1.2 0.09 4 2.2 1.3 1.3 0.85 0.09 5 1.8 1.2 1.4 0.45 0.09 6 1.4 1.2 1.4 0.28 0.09 7 1.4 1.2 1.3 0.25 0.09 8 1.1 1.0 1.1 0.16 0.09 9 1.5 1.0 1.7 0.12 0.09 10 0.95 0.95 1.4 0.12 0.08 "0.85 0.95 1.2 0.10 0.08 12 0.45 0.90 0.85 0.10 0.08 13 0.45 0.85 0.55 0.10 0.08 14 0.70 0.40 0.10 0.08 15 0.60 0.25 0.08 0.08 16 0.45 0.16 0.08 0.08 17 0.65 0.15 0.06 0.08 18 0.70 0.25 0.10 0.07 19 0.45 1.7 0.12 0.07 20 0.35 2.1 0.16 0.07 21 0.45 2.2 0.18 0.07 22 0.40 2.3 0.18 0.06 23 1.7 0.40 2.9 0.16 0.06 24 1.5 0.28 16.0 0.14 0.06 25 1.4 0.30 43.0 0.14 0.06 26 1.4 -1.7 34.0 0.12 0.06 27 1.6 4.7 14.0 0.10 0.06 28 1.7 2.6 6.6 0.10 0.06 29 1.7 2.5 4.2 0.10 0.06 30 1.6 3.0 3.0 0.10 0.06 31 2.3 2.5 0.06 TOTAL 37.4 154 9.1 2.3 Mean 1.21 4.97 0.30 0.07 Max 4.7 43 1.9 0.09 Min 0.28 0.15 0.06 0.06 CFSM 0.83 3.40 0.21 0.05 IN 1.95 3.92 0.23 0.06 4-6 •n R20/1 18 TABLE 4.5 MEAN DAILY FLOW ,SLOUGH 11 Locat ion:Gage was 2500 f eet upstream o f the mouth o f Slough 11 . Dra inage Area :1 .69 sq .mi . Dis charge .in C ubic Feet Per Seco nd ,1984 Mean Values D.y June July August September Odober 1 1.7 3 .6 2.7 2 .7 2 .221.6 3 .2 2.6 2 .7 2.231.7 3 .2 2.4 2 .7 2.24I.,3 .2 2.4 2 .7 2.•5 2 .2 2 .'2 .4 2 .6 '!..o62.2 2.'2 .4 2 .6 2.o72.2 2 .'2.4 2 .6 1.78 2.4 2 .'2 .7 2.4 1.7s2.4 2 .'2.6 2.4 1.7I.2.7 2 .'2.4 2.4 1.7112.7 2.7 2 .4 2.4 L7122.6 2.'2.2 7.4 1.6132.'2 .7 2.2 2 .4 1.6142.'2 .7 2.2 2 .4 1.4152.'2 .6 2 .2 2 .4 1.4163.4(e)2.4 2 .2 2 .4 1.3173.9(8)2 .4 I.,2 .4 1.3184.4(8)2.4 2 .'2.4 1.2 " 4 .8 2 .4 2 .4 2.4 1.12.4.4 2.4 2.2 2.6 1.1214.•2 .4 2.4 2 .4 1.1224.•2 .6 2.6 2 .4 1.1234.•2 .4 2.7 2 .4 1.1244.•2 .4 3 .2 2 .4 1254.•2 .7 4.4 2 .4 t264.•2 .'4 .4 2.4 1273.6 3 .2 4.4 2.2 128 3 .6 3 .6 4.•2.2 12.4 .•3 .2 3 .6 2.2 13.4 .•3 .2 3 .2 2.2 1312.'2.'1 T OTAL 95 .1 81 .7 85 .1 73 .2 43.4 Mea"3 .17 2 .82 2 .75 2 .44 1.45 M"4 .8 3 .6 4.4 2 .7 2.2Min1.6 2 .4 I.,2 .2 I.. (. )S loug h 11 Wal o vertopp ed du r ing the period of 6-16 t o 6 -18.Th . v alues listed are e s t imated non o ve rtopped fl ows . 4·7 • R20/1 19 TABLE 4.6 FOOTNOTES FOR DISCHARGE DATA No data available a Overtopping of berm at upstream end of slough provides part of flow Daily Mean -Average discharge over a 24 hour period in cubic feet per second.This value includes flow from the mainstem if the upstream berm of the slough is overtopped. Total -Total of daily mean discharges for the month. Max -Maximum daily mean discharge for the month. Min -Minimum daily mean discharge,for the month. CFSM Runoff in cubic feet per second per square mile is the average n umber of cubic feet of water flowi ng per second from each square mile of area drained.This value is reported only if the data is not affected by the mainstem,either as overtopped flow or groundwater flow.This additional flow from the mai nstem does not reflect the natural yield of the drainage basin. IN -Runoff in inches shows the depth of which the drainage area would be covered if all the runoff for the month were uniformly dis- tributed on it.This value is reported only if the data is not affected by the mainstem (See CFSM above). 4-8 Rl 0/1 20 TABLE 4 .7 MEAN DAILY FLOW (PROV ISIONAL ) SUS ITNA RI VER AT GOLD CR EEK D.y J une J uly Au gu st September OCtob er 1 12,200 25 ,500 22 .900 12 .500 7.600 2 13 ,1 00 24,800 2 1,500 11 ,800 .8 ,JOO 3 15.100 2S.100 19 .900 11 ,200 7,700 4 17,200 23 ,200 19 ,500 10 ,800 7,350 5 18 ,000 22 ,400 20 ,600 10.400 7 ,1 00•18,200 22.300 22 .800 10 ,300 '.600719.300 21 ,900 22 .900 10 ,600 s.roo•20 ,300 2 1,500 22 .500 10.800 '.600921.1 00 2 1.400 23.900 10 ,600 6 ,650 10 21 ,900 2 1,200 23.500 9.600 '.6001121•:;()()23 ,100 22 ,100 9.300 '.6001221,300 2 1,900 18.500 9.000 6 ,700 13 2 5 .900 2 1.200 17 .1 00 9.000 6 .150,4 3 1,500 2 1,200 15 ,600 8 .700 5 ,550 '5 3 1,200 19 ,400 14 .600 ••500 5.000 "40.600 18 .600 14 ,000 8,200 5.000 11 5 2 ,000 20 .500 14 .300 8 .1 00 4.400 1.40.600 21.700 15.200 8 .300 4 ,300 19 33.600 2 1,600 17 ,000 9.400 3 .800 20 31 ,500 21.100 18 .000 10 .400 3 ,700 21 31.400 22 ,300 19,400 11 .4 00 3 .900 22 30.900 23.000 18 ,600 10 .300 4.300 23 3 1,100 23.500 17 .900 9.000 4.5002430.000 2 1.600 2 2 ,700 8 ,300 4.600 25 28 ,400 22 ,300 30 .300 7 .950 4.000 "26 .600 29 .800 31 .700 7 ,650 3 .1 00 27 28.700 33.500 28 ,000 7 ,400 2 ,700 2.32 ,000 30.300 2 1,400 7,200 2 .400 29 30 ,100 2 7 ,900 17 .300 7,200 2 ,200 30 27,900 27 ,000 15,700 7 ,400 2 .200 31 24 ,700 13 ,600 2 ,200 TOT AL 803,200 725,500 623,000 281,500 158,500MEAN26,770 23.400 20,100 9 .380 5.110 MAX 52,000 33 .500 3 1,700 12 ,500 ••000 MIN 12 ,200 18 ,600 13 ,600 7,200 2,200 CFS M 4 .35 3 .80 3 .26 1.52 <.83 I N 4 .85 4 .38 3 .16 1.70 0 .96 4-9 R20/1 21 TABLE 4.8 MIDDLE SUSITNA PRECIPITATION GAGES Downstream to Upstream Order Location River Mile Period of Record Type of Station Talkeetna FAA 97 1941-Present Observer Curry Camp 121 8/1/84-10/31/84 Observer Curry at 1750'121 8/14/84-10/31/84 Collecting buckets checked biweekly. Sherman 129.5 6/1/82-9/30/82 Recording tipping bucket. 6/1/83-7/31/83 8/21/84-10/31/84 Sherman at 1900'129.5 6/1/84-7/31/84 Collecti ng bucket checked biweekly. 8/14/84-10/31/84 Recording tipping bucket. 4th of July @ 1600'129.5 8/14/84-10/31/84 Collecti ng bucket checked biweekly. Gold Creek 136.5 8/16/84-10/31/84 Observer Devil Canyon 151 7/17/80-Present Recording tipping bucket. 4-10 1M14/661TABLE4.9(a)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)May1984StationTalkeetnaCurry[Ievation345500__D~10.1920.103T40.1650.1060.01708090100110120130~140I150.....160.....170180.0519T200210.01220.12230.01240250.04260.15270.04280290.22300.15310.05TOTAL1.40Curry1750Sherman700Sherman19004thofJuly1600GoIdCreek700DeviICanyon1700,ooooooooooooooooooooooooooooo0.15o0.15SeenotesonPrecipitationatendoftablesforexplanationofsymbols. -1M14/662TABLE4.9(b)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)June1984StationTalkeetnaCurryElevation345500Da~102030405060.0270.088090.14100.06110120130.08~140.02I150.04......160.64N170.03180190200210220230.01240.03250.03260.07270.21280290.0130T--TOTAL1.47Curry1750Sherman700Sherman19001.000.501.65(el4thofJuly1600GoldCreek700DeviICanyon1700ooooo0.090.020.100.06ooo0.310.180.010.40ooo0.02ooo0.02o0.080.21ooo1.50SeenotesonPrecipitationatendoftablesforexplanationofsymbols. IIM14/663TABLE4.9(c)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)July1984StationTaIkeetnaCurryElevation345500Da~10.3020.0230.0140506070.018T90.10100.11110.01120.06130.11140~15TI16T.....w170.02180.13190.06200.52210.1322023T240.18250.61260.59270280.01290.08300.1631T--TOTAL3.22Curry1750Sherman700Sherman1900I0.305.105.25(e)4thofJuly1600GoldCreek700DeviICanyon17000.080.040.010.010.06oo0.04o0.26o0.030.02oooo0.020.040.190.050.06oo0.800.65O.OLIO.11O.130.02o2.66SeenotesonPrecipitationatendoftablesforexplanationofsymbols. IM14/664TABLE4.9(d)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)August1984StationElevationDayTalkeetna345Curry500Curry1750Sherman700Sherman19004thofJuIy1600GoIdCreek700DeviICanyon1700,~I......~12345678910111213141516171819202122232425262728293031TOTAL0.170.07To0.54o0.110.040.52Toooooo0.03/00.63/0.280.52/0.700.40/0.380.13/0.320.30/0.230.24/0.201.31/0.401.62/1.650.02/1.04ooooo6.65Start0.05o0.59oo0.63ooooooooT0.391.320.750.420.971.241.541.51ooooo9.41Start0.27/00.49/0.460.46/0.351.83/1.161.19/1.51o/0.768.180ooooo/0o/0o/00.07/01.26/0.260.54/1.350.29/0.440.06/0.100.60/0.280.35/0.452.05/1.211.24/1.50o/0.87Start6.65Start0.010.491.110.260.040.191.751.60oo0.01ooo0.02/00.01/0.020.01/0.01o/0.010.41/0.100.02/0.33o0.04/00.76/0.79oooooooo1.03/0.100.33/1.020.01/0.240.02/0.021.00/0.070.48/0.951.42/1.330.70/0.830.01/0.39ooooo6.28SeenotesonPrecipitationatendoftablesforexplanationofsymbols. IiM14/665TABLE4.9(e)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)September1984Stat ionTalkeetnaCurryCurryShermanSherman4thofJuIyGoldCreekDeviICanyonElevation3455001750700190016007001700D~,100-000200-000300-000400-000500-00060.06/00-00.09070.02/0.080.07-0.10/0.090.110.32/0.08800-0/0.010T/0.25900-0001000-0001100.10-00.130120.08/00.15-0.22/0.090.200.180.290.08/T130.06/0.120.340.17/0.210.040.09/0.10p.140/0.0200/0.0800/0.06I1500.020.02/0I0.06/0.....160.02/000.11/0.020/0.06U1170.12/0.06I0.04/0.120.35/0.28180.05/0.100.57/0.290.680.15/0.15190.76/0.030.920.61/0.330.510.13/0.24200.11/0.870.820.05/0.6400/0.012100002201.9500023000024T/O00.150.05/0.04250.17/0.120.180.12/0.101.982.0900/0.01260/0.0500/0.020-00270000-00280.02/0000.01-0.06r/T290.16/0.170.100.02/0.010.03-0.090300.10/0.110.210.05/0.060.06-00--------T01AL1.732.91-2.082.282.272.151.28SeenotesonPrecipitationatendoftablesforexplanationofsymbols. M14/666TABLE4.9(f)MIDDLESUSITNARIVERPRECIPITATIONDATA-(Inches)October1984StationTaIkeetnaCurryCurryShermanSherman4thofJulyGoIdCreekDeviICanyonEIevation3455001750700190016007001700D~,10.02000-0020.0400.040.06-0.040.02300.0600-0.060.0140000-05000a-06T-0.020.05-07T-0a-080.30-0.220.12-0.0590.21-0.040-0.300.0410a-0.380.010--0.01110.040.01--0.01120.160.08-0.061300-014a0-0p.1500-0I1600-0......'"1700-01800-01900.02-020T0-0210.480.09-0220.110.17-0.03230.240.15-0.032400-02500.01-02600-02700-02800-02900-030T0-03100.620.8800.450.64-0--------------TOTAL1.60-N/A0.870.58--0.26SeenotesonPrecipitationatendoftablesforexplanationofsymbols. R20/1 29 TABLE 4.9 (9) NOTES ON PRECIPITATION 1.Talkeetna FAA Station reports daily precipitation from midnight to midnight for the days noted.Where a slash (/)appears,the first number is the reported precipitation and the second number is the precipitation from 9 a.m.of the previous day to 9 a.m.of the date noted. 2."Cu rry at 500"is mon itored dai Iy,with an attempt to measu re be- tween 8 a.m.and 10 a.m.each day. 3."Curry at 1750"and "4th of July Creek at 1600"are cumulative stations measured at approximately 2 week intervals. 4."Sherman at 700","Sherman at 1900"and "Devil Canyon"are continu- ously recording stations.Where a slash (/)appears,the first num- ber is the precipitation from midnight to midnight and the second number is the precipitation from 9 a.m.of the previous day to 9 a.m. of the date noted. T -Trace amounts of rainfall (e)-estimated value -No data 4-17 M14/95~12345678910111213141516171819202122.p...23I24.....CO25262728293031TOTALMayStart0.030.060.09**0.28O.OO(e)0.731.19MTABLE4.10EVAPORATIONDATA,WATANACAMP,1984JuneJuIyAugust0.180.210.08(e)0.190.070.02(e)0.200.110.05(e)0.12*O.17(e)0.220.1100.15(e)0.120.58O.OO(e)*0.280.20(e)*0.170.19*0.140.17*0.060.000.37O.110.550.060.18*0.070.140.380.190.000.17O.OO(e)0.09(e)0.14*0.08(e)0.16*0.01(e)0.130.42O.OO(e)0.060.210.04(e)0'.040.810.07(e)0.000.64O.OO(e)0.050.28O.oo(e)0.040.810.080.000.300.150.000.120.090.000.240.000.040.05O.oo(e)0.230.030.01(e)0.14(0.02O.OO(e)0.03(0.010.03(e)0.24(0.060.125.66(e)3.16(e)3.55(e)September0.1O(i )0.090.08(i)*0.210.060.02,0.06O.12(i)0.06(i)0.040.080.020.080.12endofdata1.14MNOTE:AIIvaluesarefora24-hourperiodendingatapproximately0800ondateshown.*Nopanobservationonthisdate.Amountincludedinfollowingmeasurement,timedistributionunknown.(e)Precipitationdatamissingbutestimatedfromobserversnotesandrecordsfromnearbystations.(i)Icelayeronwatersurface.MMonthlytotalisapproximate,basedonapartialrecordonly. M15/121TABLE4.11FALLINGHEADTESTRESULTSSLOUGH9 -BOREHOLESDepthofWell1.0.SereenDateTransmissivityBorehoIelliL1ft)ofTestFt2/DayComments9-10.14624-2707/17/843.5Goodeurvef t9-10.14624-2707/31/845.4Goodcurveft,retest9-10.14624-2708/15/843.4Goodcurveft,retest9-10.0639.4-10.708/15/840.2Goodcurvefit9-10.0639.4-10.708/29/840.2Goodcurvefit,retest9-20.1467-1008/13/8450Sparsedata,poorcurvefit9-20.1467-1008/15/8492Sparsedata,poorcurvefit,retest9-20.1467-1008/29/8412Poorcurvefit,retest9-20.06310.7-12.108/15/84--Nocurvefit9-20.06310.7-12.108/25/842.6Poorcurvefit,retest9-30.14637-4007/31/843.4Goodcurvefit9-30.14637-4008/14/843.6Retest9-30.14637-4008/14/842.4RetestaftersurgingweiI.Value+0-probablyaffectedbypreviousItesting.,.....'"9-40.06311.7-13.108/13/84--Nouseabledata9-40.06311.7-13.108/13/84--Nouseabledata,retest 603608606jvIX)~o......coo6021607IIIIIII,,if:j~--I---'i~r1TiTi-!----I----t'--~-.-1!Tlf~---".---,II:I ,II II,-'IIjji!'I!I1II!rl-HJI-j:''-Ij!iII',II,i!T'I!-"IIII!~'Ir-rr---iji~i"II!II!'II'I!1----.-~-:-",-_1-1+i-J1__i•-rii'I);I"ITi~~4-~_IIi\iIjI--.'~I.1~._--'-..:j'I,I'!I,I, II'I,,I:iiiI!I''t'f'-I-f.....jnnh-iTTi:II'"-.,::!i!!II'IjII:i,!!:!II:II:I ,!II,II.LITi604. .__1.___.__'I-illr--"'-11-t'-~--r'~L-T'-:""'--'-',-~'--T, "II'T" •'I'!I!IIIiI'I I'I", , I 'I!ii,~'O-Stage,Well9-lA(feet,msl),-...---or-i'-0-Stage,Well9-3(feet,msl): I---Streamflow,SusitnaR.atGoldCreek(cfs)I 'I~-il-'-'~"--v-:i---il~---Inl-iiII,I,~!!i~:III~-i-----.-vI "'<tIX)IX)IX)iIX)IX)IX),IX),IX)IX)IX)~~.-,--d--,orp,-~r;()01.~,,--i;0---;i)--~o0'~,'~~.:..1INI,:NNI0..................I............,......II......II...............cococo'cococo'co'Icoco,...o000 I01010]000SLOUGH9 -G.'oundwaterobservationwellsPREPAREDBY:---------------(=Jlf~~f01-,-'L...~R&MCONSULTANTS.INC......l.iIIN••A.OEQL.OQlaTeHYOROLOQIOT.eURvaV'C1AdIStageComparison-------Figure4.1(elPREPAREDFOR:[}{]&OO~&0§[ID&fS©@SUSIrNAJOINTVENTURE oq-lO~It),I'--o~Ii,'II-ti':1"-]!,IiI \iI I " :,...\''IIiI:;II, 'I 'I ;1,'Il.JeriII,i!dnrfhriTrniI1~l._..t.;o-Stage,Well9-lA(feet,msl)o-Stage,Well9-3(feet,msl)---Streamflow,SusitnaR.atGoldCreek(cfs)I608607606603'it'¢'itlO,lOlO,"0'¢I'--,00I'--,"0I'--I'--60200'"L::t-;.--a...---,J..,........-....-=...\,-I 'ITnllrnI;I III'II1-i'I'IiI II,III!',•!i,ii,,I]!1"~'-'irp'I,iT,I ,IIIiI!ji'rl'I:IIIII-------...,jA,--\r'ill'I'1111I'~,j1--1r-jIf,11i;IiiII II:! 'II:I'iIII:I I:I:I I--+_.._~:-"7I-~--+-'1r--r'II:jli!I!IIJaA'i"'"""""--'-'....L:1II;I!•--iIII:II'III604l!IIIiJ.l-Lll---w~i~!~~~I"""-,' .-,'----_.1.--"';I'~iIfIj'i,!IiiI1---+1i:I':iIIIIIII!I I I~IiI,Il... _,.I I10,OpO--.---~--.-.-.,I,r;,1 II~II~T;III, III,I!iiiIiI:i,;'':I'I,I,i:II~I, :,ii'I,IIIIIi'IiiI!:i!!IIII,,.__.,,--_.--1----+.--+----.tT:-:--~-':T!1-TT1-It--inI'TnT!if~'-T'--..--I--'it:':11'it!I!ii,'it",'I''it'I'1'itI!'it'itlO'':lO,1"lOlOl,lO'llOlO........-,~,.......~It..........~.......i'.",.~~.......'~o :It),lP'0),I,C\I:ILOI....I....1'........'IC\IIC\IC\I,:,I,I'I'II"'I'I'1'--':I1'--,II'--IIT1'--1,..II'--'II'--o'0,,0IO!0II0:0P-I,.."SLOUGH9 -GroundwaterobservationwellsPREPAREDB,!,:,'_-C==:J@i\V;1=!._~V__l.R&MCONSULTANTS.INC..,.".QIN••A.allg~ggI8T.HVgAOLoDUITa.UAV.VClR.StageComparisonFigure4.I(0)PREPAREDFOR;G{]&~~&D§[ID&~©@SUSITI'JAJOINTVENTURE Loo"1-..'<tI ''<tcDcD;0'I'~CIJ(")""IIcDcDo.Q!Ii·Tl..J.._.iiI1III:-1"iI ,!---'jSUSITNAJOINTVENTUREI!PREPAREDFOR;[}{]&OO~&c~[ID&®©@--~I-Ii!Ij\,I,J,1II '•I 1I Iiii'Ti''<tIIcDI......,CIJCIJ;0o,1I--r-I 'I!!•IiIITTliiit'1t 'iJ!, i1iI1I!-i1i'lr.\iIIIILt·t"t.·i'li,'II I'!t!'I·i,,1'.,II '-~.~.~..;.-'~i-'~--"II:!I...,-j~iII!:,I~"i,,,rI1,Creek(cfs)1:!i[I11Ii'IT-'!'-lliJ:1'ii"IiII,iIi"T-.L~J.J.:IiI'II, I ,;..~r-j7"r-T--,: IIII:.II:•iiiiiiI•I!II!!!Tln-rmI1cDITl'~:Ii,•Ico, i0,SLOUGH9 -GroundwaterobservationwellsStageComparisonFigure4.1(b)IitIiI, iI!III ·'<tI1cD'C>'IcD,01,--1,'0',..~_1_j.;··h1:T/:-rlTIH-t'r+t:'j'<tcD"I"-o"cDoj-III'<tcD"'<to"cDoo-Stage,Well9-lA(feet,rnsl)o-Stage,Well9-3(feet,rnsl)i~-Streamflow,SusitnaR.atGoldI....,..,....,.-==-__-~-~==-'~"""'"=======o_~.'1.fI['"-"lI·I'Ii'Il~el/i~:il:',il.~t:!I::1"•IIaI\olQIN••A.OIiiDLOG••T.HVg"oLeaIST.aUAV.VDRePREPAREDBy.;.,~R&MCONSULTANTS,INC.606603605608Io"cDo602'<t'cD"~.p-INNI.' I0-Stage,Well9-lA(feet,msl)o-Stage~Well9-3(feet,msl)~-Streamflow,SusitnaR.atGoldCreek(cfs)Vto~~01I!,._-.-,-iIvtoCi-t\I"oI~__L, IIIiI',"n', !:I'.I..·~--r·1·',.I'IivI I~'110t\III"IoIj'j', II1iI',:j';'.']111I1'1",-j''r":III,,',III;I!III'!:IIiii.I'I".;i[iI"I;i.:II!IIIIIIIII,Iii"ir,I!I:I,Ii-t:I'-r-[ji'-I'-'1._.~.-'-~:~-'"I':!.,:"I''I'II'IIIr, " , II 'IiiiIii':IIiI'III~I!;'I'!I[,, ',I, ,I!:IiI Ii:1!1I:.I'IIII ,iIIi;.II'I.,II'II•''--'..f'.....r-",-IL -,'.r."......-.------r...II"I",., ,II',,'IIIII!'II' , I ',, , :III,i',:I 'I,III,.I:'.1I:I,:!IIii,!!IIIiII1iI[1;i'ri.'iI:'i'1I'IIIII IIIII!II40,0,0,ld..il!'l.li':~.J-','IIIII',H,I 'I'III'i:!II 'Ii, I IiII:I",.'j!I , , II'I''.II'30°IIIIiIill'i.IIi:Ii:i11ilII1IIII I!.i! :...,-,;,~.l~,LL,u'I-~."'·'-'--~'._,I._",l.--,-.I,,:I'II', IiiiI,I,,_."1";'..-.I ' IT"1'"'lI0'Li"i:iI!II,'!II:II'II1Ii!II:I::I'I, I I,:II',i''-IIJTT1mITI'IIIiii<t',ItOilIItoto:I""'"I:'rI"I!I~iI[~'!i!III~III:~,I[0'I ,I01'.0',,II I',,:!I~""".Ii, IQ),'.0-iII.tIIto(),-......''Q),o_...jIII'/"l ':"!-;'[i"liFlTT1IT:IlIIlv,to....,..~oI"II I• " IIi'II,.I...,,,-1·..--'-··ii';!i,i\:I!,:;:IjI;I I:'I!IIIIIjiIIIi~i!I IiiiIi..:'.:-.,,,j'i!!Ii11:~~-t---i!IIii:I I!,-+_..J~I11:~~Iito......tf):,IVto......Vo"o808808807804803Vto......-~o8021-...-.,..INV-JPREPAREDBY;__._.'_;5Jl~~:--~~.!...r01~__'==========R&MCONSULTANTS,INC.•NtlIl~••A.QBCLoCQI8T_HYDRDLDglSTSSUAVSVDFlIS,SLOUGH9 -GroundwaterobservationwellsStageComparisonFigure4./(d),._-_...PREPAREDFOR:[X]&OO~&0~[ID&~©@SUSITNAJOINTVENTURE •••••••••••••II•, II II F.20/1 30 5 .0 AN ALYSES 5 .1 P rec ip itation Prec i pit.at ion r eeon:l s .t T,lkeetn.f or th is pe riod 19-13·1983 were revi_ed to determine if the sunwner precipihtion reeo n:ls fo r 1934 we re unusu ,t in 'oy w.y .The tot.l monthl y precipit...ti o n y,l ues ....e r e ranked i n order,.nd <I re plotted o n the monthl y !;umu l,tive percen t f requeflc y curv es on Figu re 5 .1 .The 1984 monthl y prectpi tat tcn t ota ls ue included o n this fi gure.It Cill O be easily seen that June (10':.eeeeeda nse l a nd September (93"0 eeceecence l were d rie r tha n n o rmal,Ju ly (48""eeceeda nce l wu ilbout ave r-age,I nd August (211'~exceedence l was mu ch wette r t h<l n n ormill.Th is pattern can a lso be o bse rv ed in the pre<:ipi tation ex ceeda nce c u rve s fo r the months o f Ju ne th rough S e ptembe r (Fig ure s 5 .2 ·5 .5 ).June and September had abo ut th e a v erage numbe r o f da ys o f precipitation ,but th, r a infall was n o t as h eavy ..s n onnal.Jul y h ad gre ater than nonn.al d.ay s with light ·to ·moder ate r ainf all.\.9 l.:s t h ad more da ys than nonn.a l o f mode ra te·to ·he.avy r a inf all . Dail y prec ip itltion va tues have been pre v ious ly summari zed in T ab le 4 .8 .D.a ta f rom f ou r periods have been summarized i n Tillble 5 .1 for the 1984 network in t he midd le Susitna b .nin .Month ly and s pec if ic stO""d a ta f rom th e con tinUOus r ec ording g ag es at De vil Canyon . S he""an .and Tal ke etna ha ve been summarized in T ab les S .2 a nd 5 .3 . Ellamin at iun o f the a bove data indicates the fo llowing g eneral trend s for summ er p reci pitatio n .a lon g the Su ,itn.a Riv er betwee n Ta lkeetn.a and De vil Can y on . (a)Local e leva tion c hanges ha ve litt lo or no a ffe ct o n summ er preci p ltilltion.As seen ill T able 5 .1,preci pita tio n a t C ur ry is sim ilar at e le vations SOO a nd 1750 feet.Dur ing Sep tembe r 13·25, prec ip itation a t the S herm ao n (elevation 1900 feet)a nd 4 th of J uly C reek (eleva\io n 1600 feet)stations are about equal,an d on ly 5-1 R20/1 31 slightly higher than that at the lower Sherman site (elevation 700 feet).Similarly,precipitation at both Sherman sites is nearly equal during the intense rainstorm of August 21-26,1984. (b)Summer precipitation varies longitudinally along the Susitna River.During the two significant rainfall periods noted in Table 5.3 (August 13-27 and September 13-25),rainfall at Curry was 57-71 percent greater than that at Talkeetna.Rainfall amounts then decreased upstream from Cu rry,with the Devil Canyon site receiving the least precipitation.This general trend seems to hold true in the monthly and other storm-specific data in Tables 5.2 and 5.3,although it varies from storm to storm. Coefficients for transferring precipitation data to ungaged areas along the middle Susitna River are shown in Table 5.4. 5.2 Slough Discharge -vs.-Mainstem Discharge Linear and log-transformed regression equations relating slough dis- charge to mainstem discharge were determined for Sloughs 8A,9,and 11.The resulting equations are shown in Table 5.5,with the re- gression lines on Figures 5.6 and 5.7.Regression analyses were also conducted using slough discharge lagged by one and two days from mainstem discharge,but the regressions did not improve the deter- mination coefficient. At slough 8A,the equation developed using low-flow data (mainstem flow less than 12,500 cfs)explained significantly more variance than that using mainstem discharges up to 27,000 cfs.Under natural low-flow conditions,local runoff is less likely to be making a significant contribution to slough discharge.Slough discharge during these periods a re more closely related to seepage affected by variations in mainstem discharge,and would not be affected by local runoff . 5-2 R20/1 32 On Iy data from periods when the upstream berm was not overtopped was used for analyzing Slough 9.Maximum discharge from Tributary B was only 0.18 cfs during this period,so Slough 9 flow was pri- marily from seepage.However,there was significant water loss in the tributary between the upper and lower gaging sites.The water may have re-emerged as seepage in the slough. Data at Slough 11 were collected during non-overtopped periods.No su rface water tributaries flow into Slough 11.The relationship may be affected by local precipitation onto the slough and by subsurface flow draining from the hillslope above the slough. 5.3 Storm Runoff Precipitation and stream discharge data were collected in 1984 to determine storm runoff,water balance and mainstem-slough flow relationships.At Slough 9,the upstream berm was breached continu- ously from June 4 through August 15 and from August 19 through August 30,so storm runoff could not be analyzed.However,flow data were collected at two sites on the tributary entering the upper part of the slough,so direct storm runoff could be analyzed at these sites.Storm runoff analyses for the Slol.lgh 9 tributary for the rainfall periods of August 17-25 and September 15-20,1984 are summarized in Table 5.6 with flow patterns shown on Figure 5.8. The upper and lower gages indicated a runoff percentage of about 50 percent in the August storm.However,the percent runoff was considerably less in the September storm,dropping to 12 percent for the upper site and 1.6 percent for the lower site.Several possible reasons may exist for the significant changes in runoff percentages, including: Ca)The volume,intensity,and timing of rainfall.The August storm was more intense and had a much greater precipitation volume. 5-3 -----------_.,-----~-------------- R20!1 33 High rainfall rates occurred early in the August storm, saturating the ground early in the storm and resulting in higher runoff rates later.In the September storm,the higher rainfall amounts did not occur until late in the storm. (b)Antecedent moisture.The August storm followed a 1-week period of no precipitation,while the 3 weeks prior to the Sep- tember storm had little or no precipitation.The soil mantle was probably drier in September,therefore absorbing more moisture before su rface runoff could occu r.The precipitation timi ng previously mentioned also affected soil moisture. (c)Groundwater levels.The water level in well 9-3 was about 2 feet lower during the September storm.This likely affected the rate of water loss between the upper and lower gages on the tributary.During the August storm,mainstem flow of the Susitna River at Gold Creek was about 20,000 cfs greater than in the September storm. 5.4 Water Balances Monthly water balances were estimated for July through October for Sloughs 8A and 11 and the two sites on Tributa ry 9B of Slough 9 (Tables 5.7 and 5.8).Monthly precipitation at each site was determined from either gages at the site or from nearby gages adjust- ed by the coefficients in Table 5.4.Evaporation was estimated by using the 1984 pan evaporation data from Watana Camp,multiplied by 0.7.Flow data were recorded at the gaging stations. At Slough 8A,62-73%of the available precipitation ran off during July,September and October.The high percentage of 12490 in August reflects the storm in late August,in which the upstream berm of the slough was likely overtopped for a short period of time, 5-4 ----------------_.._---------------- R20/1 34 affecting the runoff values.Precipitation not running off as surface flow would remain as groundwater,and could seep into the slough during a later time period.However,slough discharge is very low (0.1 cfs)by late October. Slough 11 maintains a relatively steady flow throughout the summer. Even the heavy rainfall in late August caused only a minor variation in streamflow which was closely correlated to mainstem discharge,as already shown in Section 5.2.This correlation may also be illustrated by comparing average monthly flows for both the mainstem and Slough 11,and I.ooking at the corresponding monthly runoff ratios. Flows (ds Susitna River Slough 11 at Gold Creek Slough"Runoff Ratio(a) June 26,770 3.17 -0.17 July 23,440 2.82 0.77 August 20,100 2.75 0.44 September 9,380 2.44 1.19 October 5,110 1.45 1.47 (a)(Slough discha rge)/(Precipitation -Evaporation) Despite the strong negative balance in June (evaporation far exceeded precipitation),average flow in Slough 11 was the highest for the summer.(Slough"was overtopped in June for 3 days but those values are not included in the average monthly flow.)Seepage meter data from 1983 and the strong slough discharge vs.mainstem discharge correlation indicate that Slough 11 is primarily affected by mainstem flow (stage).The lack of su rface tributaries indicates all precipitation infiltrates into the watershed.The water balances for Slough 11 are somewhat spurious,since slough discharge would likely have been very similar for similar mainstem flows,no matter what precipitation fell on the watershed. 5-5 - - R20/1 35 The upper gaging site on Tributary B,Slough 9,is at the base of the hillslope,monitoring flow just before the stream reaches the large alluvial fan.The data indicate that most available water runs off as surface flow,with about 10-20 percent remaining as groundwater. However,this does not occur at the lower gaging site,which is located near the confluence of Tributary B and Slough 9.From the data in Table 5.8,it is apparent that much of the flow reaching the head of the alluvial fan seeps into the ground.As the water table drops through September and October,reflecting the change in mainstem flow and water level,the tributary loses signficantly more flow than when the water table is high.The rate of water loss from the stream is a function of the groundwater level.The higher the water table,the slower the water is lost from the tributary.The high surface runoff percentage in August is likely due to the intensity of the storm and to the higher groundwater levels (Figure 4.1 (d)). The water loss in Tributary B,Slough 9,likely explains the relatively poor correlation between seepage meter data for meters 9-2 and 9-3 and mainstem discharge.Both seepage meters 9-2 and 9-3 were located at a spring upstream of the lower gaging site of Tributary B.This site would have been affected both by mainstem stage levels and by water loss in Tributary B. 5-6 R20ilb 11VII.....TABLE5.11984GEOGRAPHICDISTRIBUTIONOFPRECIPITATIONMIDDLESUSITNARIVERTaIkeetnaCurryCurryShermanSherman4thofJulyGoldCreekDevi ICanyonPerioQ345~~7001900160070017008/13-8/275.178.148.18-6.466.655.455.008/28-9/120.160.320.32(e).0320.200.180.630.4p9/13-9/251.292.282.13(e)1.691.982.091.380.839/26-10/100.850.38(e)0.38 0.400.33-!l......2..20.13TOTAL(8/13-10/10)7.4711.12.11.018.978.016.36 jIM14/122TABLE5.2MIDDLESUSITNARIVERMONTHLYPRECIPITATIONTOTALS(Inches)PIDeviICanyon)TalkeetnaShermanP/TaTl<eetna)DeviICanyonPITaIkeetnaI1982May15-310.470.290.620.330.70,JuneIL203.980.953.350.80July5.746.371.174.190.73August4.553.700.811.380.30September7.549.141.216.170.821983May1-250.960.760.790.760.79June14-300.620.520.840.570.92JuIy1.752.131.221.831.05August5.69----4.060.71September3.2919811June1.40----1.501.07July3.06----2.690.88\JIAugust6.63----6.280.95I00September1.732.071.201.280.74 M14/123TABLE5.3STORM-SPECIFICPRECIPITATIONTOTALSDeviIP(Sherman)/p(DeviICanyon)/Per iodofRainfaI IEventCanyonShermanTaIkeetnaPITaIkeetna)PITaIkeetna)July1-1219821.982.342.031.150.98July10-1919821.461.301.360.961.07July21-2519822.084.093.281.250.63July27-3119820.601.281.021.250.59August7-1119820.491.181.570.750.31August28-September519820.883.323.320.970.27September6-2319824.886.125.841.050.84June26-July219830.720.650.341.912.12July4-919830.130.370.450.820.29August17-2619845.006.405.201.230.96VI------ITOTAL18.2227.0524.41\0AVERAGE1.110.75 R20/1 39 TABLE 5.4 PRECIPITATION COEFFICIENTS FOR TRANSFER OF RECORDED DATA Continuous Station Site Talkeetna Sherman Devil Canyon Curry Slough 8A Slough 9 (Sherman) Gold Creek 1 .5 1.2 1.7 1.3 1.07 1.2 1.0 1.4 1.07 0.9 1.3 To obtain precipitation estimate for above sites,multiply precipitation at gaged site by the appropriate multiplier. 5-10 LIlI..........R20/1b2TABLE5.5REGRESSIONEQUATIONSFORSLOUGHDISCHARGEvs.MAINSTEMDISCHARGESlou.9..!:lPer iodRegressionEquation~PointsComments8AJuly3 -October30,1984Q8=-.08+.00017QGC.0.53115Flowrange(2,200-(excl.8/23-8/28)logQ8=-5.0+1.29logQGC0.7911527,900cfs),Sept1 -October20,1984Q8=-.67+.00025QGC0.7361Lowrunoffperiod.logQ8=-7.13+1.85logQGC0.9161(2,200-12,500cfs)9Sept8 -October30,1984Q9=-.62+.00039Q~C0.8256Flowrange(2,200-logQ9=-4.1+1.15logQGC0.845611,400cfs)11May25-October22,1983Q11=1.52+.000105QGC0.76156From1983sloughreport.June1 -October30,1984Q11=1.3+.000072QGC0.68153Flowrange(2,200-logQ11=-1.5+0.45logQGC0.7615340,600cfs)May25-October2~,1983Q11=1.43+.000087QGC0.63309&June1 -October30,1984 M15/124TABLE5.6STORMRUNOFFANALYSESSLOUGH9TRIBUTARYSlough9Tributary,UpperSiteSlough9,TributaryLowerSitePrecipitationPeriod(1984)08/17-08/2509/15-09/2008/17-08/2509/15-09/20RunoffPeriod08/17-09/0609/15-09/2808/17-09/0609/15-t!9/28TotalPrecipitation(Inches)6.461.406.461.40Max.DaiIyPrecipitation(Inches)2.050.612.050.61TotaIPrecipitationVolume10.962.3721.914.75(miI I ioncubicfeet)TotalRunoffVolume6.4681.08112.1810.149(miIIioncubicfeet)Basef IowVoIume1.0340.7980.2720.073(miI Iioncubicfeet)StormRunoffVolume5.4340.28311.9090.076V1(miIIioncubicfeet)I.....N%Runoff50%12%54%1.6%GroundwaterLevel,606.8604.8WeI I9-3MaximumDaiIyFlow31,70011,400SusitnaRiveratGoldCreek M15/125TABLE5.71984MONTHLYWATERBALANCESSLOUGHS8AAND11June~AuqustSeptemberOctoberSlou~F Iow,Q(cf s )2.989.191.700.63I(miI Iioncu.ft.)7.46(3-31)24.624.411.69Precipitation,P(inches)5.468.162.520.78(miIIioncu.ft.)19.1428.618.852.72Evaporation,E(inches)2.022.490.800(millioncu.ft.)7.07(3-31)8.722.800(P-E)12.0719.896.052.72Q/(P-E)0.621.24(1)0.730.62Slough11U1IFIow,Q(cf s )3.172.822.752.441.45......w(miIIioncu.ft.)8.217.587.356.323.75Precipitation,P(inches)1.494.726.782.150.65(miIIioncu.ft.)3.9318.5526.608.442.56Evaporation,E(inches)5.662.212.490.800(millioncu.ft.)22.148.689.763.130(P-E)(millioncu.ft.)-18.219.8716.845.312.56Q/(P-E)-0.170.770.441.191.47( 1 )Slough8AIikelyovertoppedinlateAugust. M15/127Table5.81984MONTHLYWATERBALANCESLOUGH9,TRIBUTARY913J!!.!.:t:AuqustSeptemberOctoberSlough9Tributary(UpperSite)Flow,Q(cfs)-2.620.91( 1 )0.'30(millioncu.ft.)-7.022.541.34Precipitation,P(inches)-7.442.110.87(millioncu.ft.)-12.623.581.48Evaporation,E(inches)-2.490.80(mi I Iioncu.ft.)-4.211.350P-E,Precipitation-Evaporation-8.412.191.48Q/(P-E)-0.831.16(1)0.91VIISlough9Tributary.......p-(LowerSite)Flow,Q(cfs)1.214.970.300.07(mi'lioncu.ft.)3.2313.310.780.19precipitation,p(inches)5.257.442.110.87(millioncu.ft.)17.8125.247.162.95Evaporation,E(inches)2.212.490.800(millioncu.ft.)7.508.432.710(P-E),Precipitation-Evaporation10.3116.814.452.95Q/(P-E)0.310.790.180.06(1 )AffectedbyrunofffromstorminlateAugust. ? t :( ORDINATE VALUE 20 In Figure 5.1 MONTHLV RAINFALL E;(C::=DANC~CURVES T AL:<EETNA,ALASKA PROBABILITY OF MONTHLY PRECIPITATION LESS THAN 99 98 :fS 90 80 70 60 !:O 4Q !O 6 ::==:. 5 10 9 8 1 =. 'o~o ,..-r-t--,-_._0 ~.....::...-. • .......'....... I I.I 1.-,~ I ,,........."' I,I '::lI ,""I ~,..."" !I I 1,1''I ..............., I I I I I I......I I 'IIU I 1!'loJ .................. i lJ n e'"i ill -',""",,-(0)'I L.._ ~..--- --::~f 0":'\;.:: -' '~: ~~ H--+---.---"--'-i--+.+8 -,-~-rrr,H+++-+[Ul 1·in4 '~tF f-l---!-+-'+-h-l-H-t-'t f-,t --~-- TfIf illl' --4-H- l • , I 1 PREP~RED BY; --.J:Z~~::-f01======~=_ ~&M CONSULTANTS,INC. PREPARED FOR: 1XJL~'[RlG&0 ~[ID&®©@ SUSI roo"-JOINT VENTU"E 5-15 .~. -'5 1,23"- . 2.0 - I I I I uu,........, ,,I : I ,'I 11 :',I I I I I I "I Ii!i I I I I ):,.I I '!''!::i i:I,;',,,,,,I I'I I I I , 1.Q .9 .8 .7_ .6 f-+, .5 - .4_ 1ft .3 lI.I X Co) ~..2 _ z ,, 0 I .,,I...h ~",I c('\,,....I ',I...\"! \ • -fO Is:i~:,I I ,\.:i~~\,Y':,,'!i ',Ia., '"::'\':.I )i ',I 1Co)"' IlI.I ~'-''':!I.,i II:\:,1,'!,'.1\1 •I I;I:",.',I : i I 1 I• 1 :I;a.~.09 _ .08 _ .07 _ .06 _ .05 _ .04 _ .03 _ .. .02 _. I :I, '..."''"',-,,~.... \\"' : I I :\"i I ..,I \I \I I !I I , \:\I \I .01 j :::\[ 0 10 20 30 40 50 60 70 80 90 100 0/0 OF DAYS PRECIPITATION EQUALLED OR EXCEEDED PREPARED 8'1':PREPARED FOR: '-':1!i"~]~:/1 lXJ&rm~&c ~[ID&®©@~r_.. R&M CONSULTANTS,INC. 5L:SI T~jA JOINT VENTli';t.,..a.......aea..aa .•"....g_g..aw ........."'."0 •• ')-1';-----------------_...__._--,--------- 5f3 i -- 2.0 11 1.0 .9 .8 .6 4 .3 11 I I!II i :I , I,.I I .1 .09 _ .08 _ .07 _ en 1&.1 % U ~.2 zo...<... ii: u 1&.1 a:: l1. .02- .,"",'IT I .......V I I i-·,'-·~',~ ~!"I:, 1'1 ''\~;!:"I\'I IIQ 4;1 'i i I Ii :':Ii:, I :I :-,\Ii I i,-''I ~i I I:'i I :!,I I I II I I'I I !!,I 2! \ I ! !!\ I "1' \\ \ \ I I I 100 1 I '1 ,.01 -..:...--------.l...---...:...----...:...--..:.J-.:....,'J3---~~'-----------------o 10 20 30 40 50 60 70 80 90 %OF DAYS PRECIPITATION c:aUALLED OR EXCEEDED ?REP~RED BY. 5-17 PREPARED FOR; [X]&~~&c ~[ID&~~@ 2.0 -,-I I I ,,~0.0 -~I I i~u ....J'..-:3I~ I I I , I i ,, :!I ..Iii I!;:'.:I ,'I I :'.\i I ."'i '~,,,~i !:..I I :\\.I;i !I:I II':II i i II i I I II ,, I I ! ,,,I I II.e ' I I .9 _ .S'_ .7_ .6 .5 .4 .3 _ en 1&,1 ::c (,Jz ,-.2 _,,-." Z I ....~,', 0 I ).,.'I '""'-\1 \'t'i-'..II''I',,,'...I :\J ,.".",,,Ice,.I . \\i i I ~'''''~''''• I i :i I III II !Iii!. I I... ~'.,I!'II i ,' I III ;!I'I,I '..,a.,\:..'",, (J I i:, I :1\1 [\'.No'' I I '.I I'.;II'iii!r j;' 1&,1 .1a:.09a.- .OS .. .07 - .06 .05 .. .04 - ,. .03 .. .OL , l- I I .01 ! a 10 20 0'OF,0 I \d i I I J \i·I I I I I \'it 1 I 30 40 50 60 70 DAYS PRECIPITATION EQUALLED OR eo 90 EXCEEDED tOO i P"lENRED BY: F'1&M CONSULTANTS,INC. to ......-..---_..._--------- J>REPARED FOR: [X]&~~&0 ~[ID&@~@ ...._._-------------_._---- .-:! '---,----'. ._~...-~-~ l---~---f -------·"1----------'1! 90 --t·._.:c..-- _-.:..~--=.~..j _.c:;-c ~:;;=::~~~::::-=;::-.:-J .-'-"--=--..::....:.------. .-_.L.....-_.__.--1----.---- ! -:.::-.----.:="'-'--__·_.l +."-=_:::._=-.:::_=-:.-=-:.:c:':--==-='--=-:~:---=-'::-:-J PRECIPITATION EXCEEDANCE I -_=-_~---'-------- ___.----....;-...;---"-c...; -:=~-:.=~~:::.-:--:r-:~~~i=~-::-:-· -.,'r'"-.. ~--·~--T--~---_..--t---::-·_-·-r-_·-~.__=-..-f==~~~--~~:-.~-~~---T-~--~~--~--_:.:-.--.,-~-~~J _••__•:.,._______L.•• -----------.--I -_._---'----------=--====r::==:::-:::.-:--....=1::::--.:-.:...--:-....::-_.:.::...::=:..--::_::-::-..::..-:--:==_:...:.::::--==-::.: ------_.~--.._---~-- ! I .f----.--~:--.---...,----r--~• -----'--.--<il9 ...----------'---'-o 10 20 30 40 50 60 70 80 PERCENT (Ok)OF TIME PRECIPITATION EQUALLED OR EXCEEDED .0' .0' l---;-- .'I I ',. ,_.~.._~'"--~~- ~-r=_-'r:1-~ .1 __...1-,----,---,---==-,,--,-'1.. .0 I--=f'='~'_---= .0 -f=~ .0 ~----~.._.. !.=.:....0:_';-1--- 1 ------., .0 ,7 -;_ .5 __ .0 .0 .6 __. .3 .2 CURVES i ,-TALKEETNA.ALASKA -1 l_._•._--.-..-----:::::::--_-..--=:-:-;..c.-:-:..SE PTE MBER---·-----·--··---·:-1 t-:--_:_.-.--~-..------1-'-~7"~~·-l·-·~·-t----±~--;---------~.-.---.----r----..-.---.-l___-..- -T ---__'__11 l -~--··.l·---·--r.-,---J--L-+-···!·--,--,~·,@1972-81 -·i·--~-·---t·--·--t ._._._-~~ 1.0 .1-------I-~i-.i·-------~-----e:.1~.?_2 ..----:-----------r-----------~ .9 --)C~~;;t1t;~:r~-:~::-~~~?~-.~~~;;!~~ -'::"::~1 2.0 zo I- ~ I- Q. U l.LJa:: Q. \ ~ \ .... h ;.,.:.. "',j I. -', ...,:'.'i :';J',,,,~~~.~'. "'t'.... PREPARED BY; R&M CONSULTANTS,INC. Figure 5.5 PREPARED FOR: [X]&~~&CI ~[ID&®©@ SUSITNA JOINT VENTURE 5-19 9,II5'II4i--~0-----~--6I,IIIIlI:!':lIii,ii'IiiiII "':',I!J,I,,~-! 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".>~;';>i;.~ t:'. •~-,:.~: I \\1 f:;c~P(. '.•H'.-1' ;,~ :?,t~/'~J~:\:':.( .,\ -...;~j~j~:~L~·;:, o , 1,000 2 "J 5 -+~I)-;8 9 10,000 a SUSITNA RIVER at GOLD CREEK (cfs) 5 5 6 7 PREP4RED BY; R&M CONSULTANTS,INC. Figure 5.7 5-21 PREPARED FOR; [j{]&00 Z6&CI §[ID&®©@ SUSITNA JOINT VENTURE '. r -=, :j .-_=1 "-~ QUGH3=-5 ~EAMtrnW::::.EATtERNS- ~:_:'.-~'- 4 3 2 _ :I I • 5 4 i i .-- I I .- --OIl-U o I , "-": V '\ .J -~\' I I '\ "\ I I I -StGUGH~ne"-Q"~'toPP~d t--+-+-t-rtOSLOUGH--9 'TRIBUTARY (lower gage) f-+-H,.--riil....~SLOUGH-9-JRIBUTARY (upper gage) ~g.~' T _ ~,cr.: ·:-1 __-_ .----~E= -~'~~-~¥2 -_=:+==-Ci \, \ ..1 ,\ _._!:cleo _:i ...:.,._ -,~_...:\c--. .-I .. 10 -t 20 JUNE .i 30 i 10 -, 20 JULY ~-~i --1--:-4~-+~j±~~~i'§=t~ 30 10 20 30 10 20 30 AUG SEPT r== 10 OCT PREPARED FOR:PREPARED BY: R&M CONSULTANTS.INC............................_00.......u ...,.",•.• Figure 5.8 SUSITNA JOINT VENTURE 5-22 --_...._----._------------- -._-.--- R20!1 40 6-' a pp rop riate the middl e be used t o Talkeetna precip itation records ,ad justed b y an coefficient ,may be u sed t o e stimate precipit at ion al o ng Sus ltna Rive r .The estima t ed p r e c ipi tat ion v alues may estimate local r un o ff into sel e cted sl oughs . d .S trong l inear and logarithmi c relationsh ips exist at S loug hs 8A ,9 , and 11 between main stem d is charge and s lo ug h d isch arge d Uring periods when the ups tream berm o f the sl ough is not ove rt opped . These r elat ion sh ips may be us ed t o e stimate groundwate r dis charge under with -project c onditions .Sl oughs will also recei ve local su rfa ce run off . c .Water level i n the mainstem is the primary c ont rol cf t he g roundwater level in the allu vial s oils a dja c ent t o the sl oug hs .Und er with -pr oject c ond itions .the redu ced g rou ndw ater levels w ill affe ct t he r a te of runoff a cross allu vial fans s uch as that at T ributary B in S lo ug h 9 . b .A high percent a ge o f p recipitation (60-90':.)ru ns o ff the steep r ock hitlslope s a t;'ove S lo ug hs SA and 9 .How ev er ,t he t ribu ta ry streams may lose a si gn ifi ca,lt po rtio n o f their surface fl ow t o groundwater i n allu vial fa ns at the base of the s lo pes su ch a s at S lo ugh 9 .Th e r ate o f lo ss is aff e cted b y the d epth o f the water ta ble . The results o f the 1984 water balance studies ,t aken together with results frem previous s tudies in t he a rea ,lead t o the foll owing con clusions : 6 .0 CONC LUSIONS •• e .Examinati on o f watershed characteristics c an g ive an indicatio n o f h ow sloughs which have not y et been studied would react to c hanges in ma instem fl ow .although with -project sl ough discharges c o uld not be a ccuratel y quantifi ed . R20/1 41 7.0 REFERENCES 1.Acres American,Inc.1983.Susitna Hydroelectric Project,Slough Hydrology Report,prepa red for Alaska Power Authority ~Ma rch. 2.Alaska Department of Fish and Game -Su Hydro..1983."Susitna Hydro Aquatic Studies,Phase II Basic Data Report,Volume 4: Aquatic Habitat and I nstream Flow Studies,1982.Appendix C Temperature Data". 3.Alaska Power Authority.1984.Alas ka Power Authority Comments on the Federal Energy Regulatory Commission Draft Environmental Statement of May 1984,Volume 9,Appendix VII Slough Geohydrology Studies. 4.Cooper,B redehoeft,and Papadopu los,"Response of a Finite-Diameter Well to an I nstantaneous Charge of Water",Water Resources Research, Volume 3,No.1,First Quarter 1967. 1982."Susitna Hydroelectric Project,Slough Report",prepared for Acres American R&M Consultants,Inc. Hydrology Interim Incorporated,December. 5. 7-1