W.PConnorandA.P.Garcia,UntedStatesFshandWdlfeService,POBox 18, Ahsahka, daho 83520 ema :w afn [email protected] A. H. Connor,Un ted StatesForest Serv ce, 12730Highway T 2, Orofino,ldaho 83544 E.O. Garton,Department of F sh andW dlife,U n versty of daho,Moscow, ldaho 83844- 1 136 and P. A. Grovesand J. A. Chandler,ldaho Power Company, 122T dahoStreet, Bose, daho83702

Estimatingthe CarryingCapacity of the SnakeRiver for FallChinook SalmonRedds

Abstract

Recovery planning ibr impeiled populationsofanadromous salmonidscan require estimatesofthe carrying capacityof a riler fbr reddsfterealler. rcdd capacit!). Wc cstjmatcd redd capacilyfor the I 06 known fal I chinook salmonspawning s ites in the upper and lou cr rcachesofthe SnakeRiver We useda modification of the InstreamFlow IncrementalN{ethodology to estimatespawn- ing arca (m:) for L2 representativestudy sites.We estimatedthat one redd occupied70 n: of spawningdrea at the most heavily ulilizcd sitc. Spa\\'ning area $,as estimatedat the 12 study sites using a stable flow that was implementedto prevent redd de- walering.and two othcrflows that enconrpassednatural fluctuation. We estimatedredd capacityfor eachstudy siteby di!iding the alnounrol spawningarca modeled at eachofthe threeflows by 70 m:. Wt input the redd capacityesiimates lbr the stud"v'sites into &e equalion fol a srralified randon sanrpleto make three estimatesof redd capacit! fof all 106 known spawning sites.The estimatesrangcdbclwccn 2.,116and 2.5?0 redds.We concludethat the SnakeRiver can suppoftthe 1,250redds needed to satisfy EndangcrcdSpccics Act de listing criteria. However. annualsurveys should be conductedto eventuall] detemine if rccruitnent cfficiency is affectedby densily dependentfactors beforethe recovery goal is achieved.

Introduction ing habitat betweenHells Canyon Dam and the upper end of Lower Granite Reservoir (hereaf- The constructionof hydroelectricand diversion ter, the )(Figure 1). An estimateof dams has eliminated or reducedspawning habi- retlLl. rpirL itl u r. neededto helpJefine u recor- tat usedby anadromoussalmonids in the Pacific ery goal to match the remaining habitat. Few Northwest (Wunderlich et al. 1994, Kondolf et empidcal datawere availablewhen the recovery al. 1996,Daubleand Geist2000). Spawning habitat plan loss is one factor for the imperiled statusofmany was drafted.howeveq and biologists relied judgement anadromoussalmonid stocks.The development heavily on prot'essional to establisha (National uireco\er) plan:for imperilcdstocks sometimes proposedrecovery goal of2,500 adults requircsestimating the number of reddsthat ex- MarineFisheriesService 1995). The recoverygoal isting orlost habitatcan carry (hereaftel reddca- equatesto a redd capacity of 1,250assuming an pacity). This was the casewith SnakeRivcr fall cqual sex ratio for spawne$. chinook salmon (Onutrhz-nchus tshatr.rtsc htt). a While the SnakeRiver tall chinooksalmon stock that was listed as threatenedunder the En- recoveryplan was being deveJoped.we beganto dangeredSpecies Act (ESA) in 1992 (National studyspawners and their habitat.Water flow from Marine FisheriesService 1992). Hells CanyonDam was alsostabilized at approxi- Snakefuver fall chinook salmonwere displaced mately 260 mr/s during the spawning and incu ftom the historic spawning area near Marsing, bationseasons to preventredd de-watering (Grcvcs (Groves and Chandler 1999) by the con- and Chandler 1999). In this paper, we use data struction of Brownlee, Oxbow, and Hells Can- that were collected after the proposedrecovery yon dams(Figure l). By 1975,Lower Granite, plan for Snake River fall chinook salmon was Little Goose,Lower Monumental, and lce Har- written to estimatefall chinook salmonredd ca- bor dams impounded the lower 224 km of the pacity undera stableflow regimefor two reaches SnakeRir er lerring - | 7.1Lm of riverinerpawn- ofthe SnakeRiver Wealso discuss the suitability

NorthwestScience. Vol. 75, No. ,1,2001 363

O:001 br-rh€\.nhRe(S.i.m,li.,\i$r,a!on ,\llriChhnx.rcd Washington Idaho

Clearwater l(AVCT

Grande Ronde River

Oregon

r ILu.ro.r-Lct Rrver Sal-mon R:-ver

+ Snake River N 50 0

.- Flow trr,r.iitrj

Figure l. The SnakeRi\'cr including the locationr ol the upper,middlc. and lower reaches.and rhe hisroric spaw ng area near Marsing (approximaterkm 685), maiof tributarics.dams. and U. S. Ccological Survey gaging stations.Thc locations referenccdb! numberafe: |) Bro$nleeDamI2) OxbowDam;3) HetlsCanlon Dam;.l) UpperReachSnake Rivcr:5) Site 3 | 1.5: 6) M dle ReachSnake Rilerl 7) Anaronc. \\,'ashington;8) l_o$cr Reach SnakeRiler: 9) Lower Cranire Resen oirr l0) Lower Gfanite Dam: 11)Little Goose l)am i 12) Lower lvonumcntitl Dam: and | 3) lce Harbor Dam.

36,1 Connoret al. of theproposed recovery goal (1,250 redds) in light 1998).At least 20 substratemeasurements were of the reddcapacity estimates we generate. madeper transect(Geist et al. 2000) andthe mea \urementlo(Jlion5 anJ.hunnel elerrlion:' uere StudyArea sun'eyedusing the total station. We determinedthe meanlong-axis diameter of thedominant subsfate For a detaileddescription of thc SnakeRiver, we in eachvideo image(Groves and Chandler1999). rcfcr the readerto papersby Groves and Chan- dler (1999) and Dauble and Geist (2000). The We madebathymetric maps of eachstudy site SnakeRiver can be divided into threereaches (Figurc2) by ioputtingthe substratemeasurement (Figure 1) basedon differencesin channelmor- and channelelevation locations into AUtoCADG) phologyand dischargc. The volumeof waterflow and Sofidesk@mapping sofiware. These maps ing throughthe upper reach is controlledbyreleases included the distribution of substratewith long- of waterfrcm the Hells CanyonDam (Grovesand axis diamctersranging from 2.6 to 15.0cn (here- Chandler1999). The lmnaha,Salmon, and Grande after, spawning substate patches)and the loca- RondeRivers (Figure 1) provideadditional water tionsofredds we suneyedbetween1991 and 1994. to the lower reach of the SnakeRiver and cause EstirnatingSpawning Area natural flow fluctulltion during spawning. Between 191J6and 2000. therewere 78 docu We collectedvelocity calibration data (Bovee and mentedspawning sites in the upperreach, 11 in Milhous 1978)at verticals(Figure 2) spacedalong the middlereach, and 28 in thelower reach(Garcia the primary transectsusing U.S. GeologicalSur et al. 2001).Spawning sites were deUned as ar- vey (USGS)gear or an acoustioDoppler cunent easwhere redds occurred within a relatively con- profiler We surveyedthe location of the verti- tiguous patch of medium gravel to small cobble cals using the total stationso that verticalscould (long-axisdiameter 2.6 to 15.0cm; Grovesand be positionedon the bathymetricmaps (Figure Chandler1999). 2).Velocity calibration data were usually collected duringspawning (flow rangesupper reach = 250 Methods to 300 mr/si lower reach= 290 to ,130mr/s). We also collected stage-dischargedata (Bovee and Study Sites and l\,4aps Milhous 1978) over a wide rangeof flows (upper reach260 to I,190mr/s: lower reach 280 to I From 1991to 199,1,we selectedfive known spawn- ,300 m3/s).All velocity calibrationdata were collected ing sitesfor studyin the upper reachand sevcnin during periodsof stabletlow. the lower reach.We did not selectany study sites in the middle reachbecause of low spawneruse We calibratedthe hydraulic model lFG-,1 from 1991 to 199,1.We establishedone primary (Milhouset al. 198,1)to allow the simulationof transect(Figure 2) at I I of our study sitesto rep meanwater column velocity at the vefiicals over rcsent the habitat used by fall chinook salmon the spawningsubstrate patches at eachstudy site. spawners.Three primary transects were establ ished Velocity adjustmenttactors were calculatedby at the largestand mosl complex study site at river dividing thc simulatedflow by thecalculated flow kn (rkm) 266.5.The locations ofthe l4 primary to assessmodel fit. AII ofthe velocity adjustment transectswere surveyedusing an elecffonictotal lactors fell in the range of 0.8 to 1.2 indicating statl(]n. IFG-,Ifit the data(Bovee and Barrholow 1995). We used stagedischarge regressions developed We aiso establishcdnufrerous supplemental lbr the IFG-,I datadecks (Milhous et al. 1984)to transcctsat approximately I 5 m intervals upsteam simulatewater deptha1 the venicalsover the spawn- and downstreamof prirnary transectsto bound ing substratepatches at each study site. Depth the spawninghabitat. We usedan 8 mm video was simulatedby subtractingthe surveyedchan- camerapositioned L2 m abovethe ground to record nel elevationat eachvefiical from the predicted substrateabove thc waterline alongeach primary watcr surfaceelevation. and supplementaltransect. Mean long-axisdiam- ctcr ofthe dominant substratewas assgssedvisu- EstimatingSpawning-Area-per-Redd ally in water less thirn 0.6-m deep. We used an underwatervideo camcra to tape subsffateim The IFG-,I model typically representsthe stream "cells" agcs in water >0.6 m deep (Groves and Garcia bed in the form of rectanglescalled

SalmonRedd Capacity 365 Transect

Spawning substr

Cells =-Flow Verticals

45 15 0 ltl Scale (meters) ConLour intervals 0.5 meters

Figure 2. Thc stud) srte at rkn 311.5 including rhe localion of ihe spavning substratepalch. primrry rransect. \'erlicals,cell boundarics.and lail chinook salmon redds.

366 Connoret al. (Milhouse et al. 198,1).We usedvetical spaclng llows observedin thelower rcachduring ow study. to determinethe width of each cell (Figure 2). We estimatedredd capacityfor eachsite at each We determinedcell length two ways. For I I of simulationflow by dividing spawningarea by the the primary ffansectswe basedcell lengthon the ninimum value of spawning-areaper-redd cal- marimum distance redds were located up and culated as describedin the previous section of downstreamof the transect(Figure 2). We sur methods.Finally, we estimatedredd capacity with veyed one or two reddsat the primary tmnsects a 95cl. confidenceinterv;rl for all 106known spawn- representingthree ofour upstreamsites. although ing sitesin the upperand lower reachesby input- the substratepatches atthese sites were obviously ting the rcdd capacity estimatesof the 12 study largeenough to supportadditional spawning. We sitesinto the equationtbr a sfratifiedrandon sample determinedcell length at thesethree sitesby us- (Krebs1999). ing the bathymetricmaps to determinethe up and downstreamdistances within the substratepatch Besults that was representedby the primary transect.We areaestimates fbr the l2 study Snake thencalculated the areaofthe spawningsubstrate Spawning I m: the year in eachcell by using AutoCADo and Softdesk@ River sitesranged from 601 to 3,239 rnappingsoftware. the maximum number of redds was surveyedat eachstudy site (Table 1). Spawning area-per-redd We used IFG-4 and the stage-dischargere- rangedfrom 70 to 683 m'] (Table 1).We selected gressions water meancol- to simulate depth and 70 ml as the arearequired by spawnersto con within cell underthe flow that umn velocity each structa redd. ocr'urredthc lear ue surreyedlhe mu\imum numberofredds at eachstudy site.We calculated Spawning areaestimated fbr the study sites the simulation flow for this analysisas the aver- under the stableflow regime rangedfrom 601 to age of the daily mean flows betweenthe onset 1,234mr in theupper reach, and from 773to 13,239 and end of spawning.Daily mean flow records mr in the lower reach (Table 2). Redd capacity for all simulationswere obtainedtiom USGS gages rangedfrom 9 to 20 for study sites in the uppcr at Hells CanyonDam (rkm 398.6)in the upper reach, and fiom I I to 189 fbr study sitesin the reach and Anatone. Washington(rkm 269.7) in lower reachrTahle 2r. E'limrled 5pauning area thelower reach(Figure 1). and redd capacity increasedfor the lower reach sitesat rkm 245.2(up 21 redds),rkm 266.5 (up 2 The calls with spawning subsfate were con- redds), rkm 267.8 (up 5 redds), and rkm 267.9 sideredto be suitablefor spawning if the simu- (up 3 redds)as the simulationflow increasedfiom lated depths rangcd from 0.2 to 6.5 m, and the 280 to 520 mJ/s(Tabte 2). simulatedmean water column velocitiesranged from 0.4to 2.1m/s (Grovesand Chandler 1999). The infbrmation required for estimating the We calculatedspawning area (m'z) for eachstudy reddr.aprcitl of lhe 106knoun spauning rites site by summing the areaof spawningsubstrate in the upper (n = 78) and lower (n = 28) reaches in rhe cells thal met the abovesuitability criteria of the SnakeRiver is given in Table 2. The three for water depth and water velocity.We then esti- estimatesof rcddcapacity were 2,4461I ,439 (upper mated spawning-area-perredd at eachstudy site reachflow = 260 mr/s; lower reach flow = 280 by dividing spawningarea by the maximum ob- mr/s),2,55811,427 (upper reach flow = 260 mr/ servedredd count. s:lower reach flow =,100mr/s), and 2,570t1,421 (upperreach flow = 260 mr/s; lowerreachflow = EstlmatingRedd Capacity 520 mr/s). We simulated water depth and mean water col- umn velocity fbr sites in the upper reach of the Discussion (i.e.. Snake River under the stableflow regime Assumptionsand Limitat ons 260 mJ/s).To accountfor flow fluctuationcaused by tributary inflow in the lower reach,we simu- We assumedthat redd capacity increases as spawn- lated water depthand meanwater column veloc- ing areaincreases. Aoonelation analysisbetween ity at flowsof280,,100, and 520 mr/s. This range spawningarea and maximum redd count would includedthe minimum andmaximum daily mean test this assumption.Gallagher and Gard ( J999)

SalmonRedd Capacity 367 TAtsLts I Eslimatesof spawningarett (SA) per redd (SA/redd) for l2 fall chinook salmon spawningsites along rhc upper and lower reachesof lhc SnakeRiver basedon thc lto\' (mr/s) during spawningthe year rhc maxinmm numbcr ol redds $cre countedat each sitc,

Si!c Simulalion SA Maximun redd SA per redd flo\ (nl^) (m') (m')

Upperreach 311.5 1992 261 662 l 132 l l.l 1993 210 601 I 601 1991 262 5 211 3:19.6 1993 2',74 1.366 2 683 352.8 199'+ 262 665 2 333 Lowcr reach 1991 380 3,0'7',7 1 4:10 259.0 1993 ,ll I 1',73 tl 70 261.3 l99l ,165 1.977 20 219 266.5 r99l ,lll 13.239 30 '1,11 261.1) r993 ,11| 1.735 ,l :13,1 167.8 1993 4lI 1,1t2 6 235 261.9 1993 ,111 r.262 90

TABLE 2. Eslimatcsol redd capacitl for l2lall chinook salmonspawning sites along thc upperand lower rcachesofthe Snakc Rivcr baseda stableflo!r'of 260 mr/s in the upper rcach.aDd a rangeofflows in the lower reachof 280.,100,and 520 nr'/s.The stalist ics for estimatingtotal redd capacil)_lbr the I 06 kno\\'n spawningsites in the upper (n = 7 8) and lowcr rcaches(n = 28) are also qilen.

Spawning area(mr) Redd capacity by ilolv (mr/s) by flow (mr/s) Site 260 520 40t)

Upper r€xch 3t1.5 662 9 601 8 3t2.3 l,2l.t l8 3.19.6 20 352.8 661 l0 5 Sanplcnean 13.2 Samplc\ ariance t8.7 Lowcr reach r.876 3.387 1.187 21 ,18 ,18 259.0 113 773 113 11 lt ll '71 26r.3 1.971 1.9',71 1.911 1t 1l 266.5 13.105 13,239 13.239 187 189 189 )61.4 1.715 r.735 t.7.15 25 25 25 267.8 1.067 1,412 L5 20 20 26t.9 1,262 1.262 t.1'75 t8 l8 21 1 '7 ',7 Samplenrcan 50.6 54.1 55.0 Salnplevrriance :1.022.0 3.9,18.3 5 9t 3.0 rcpofieda signiftcantconelation between chinook spawnernumber was critically low, thus the ma- salmonspawnerdensity and an estimateofspawn jodty of the study sites was under utilized. Fall ing areacalledweighted usable area (Bovee 1982). chinook salmonredds counted during aerial sur- We did not conducta conelation analysisbecausc veysincreased from 4l in 1991to 255 in 2000

368 Connoret al. (Garcia et al. 200l). We may have an opponu- asflow dccreased.This suggeststhat the amount nity to validateour reddcapacity estimates ifadult of spawning area might limit redd construction fall chinooksalmon escapement to the SnakeRiver at somelow flow level, which in tum could have contlnuesto rncrease. a temporal efTecton productionby reducing the We equatedthe recoverygoal of2,500 adults numberof retumingspawners 4 to 5 yrlater Stage- to the SnakeRiver spawninggrounds to a redd dischargedata collcction under drought condi- capacityof 1,250assuming an equalsex ratio. tions would increasemodeling opportunities, The information on the sex ratio of wild Snake therebyproviding a betterunderstanding of how Riverfirll chinooksalmon spawne$ was inadequate low t'low aflects redd capacity. for our modeling becauseit is limited to small samplcsof carcassescollected haphazardly dur- BeddCapac ty ing spawningsurveys. However, the Washington We reviewedthe literatureat theonset ofour study Depanmentof Fishand Wildlife propagateshatch- to understandthe problems othershave encoun- ery SnakeRiver fall chinook that arephenotypi- teredwhen estimating redd capacity. To ourknowl- cally andgenetically sinrilar to wild fish (Bugefl edge there are no peer-reviewedpapen on this et al. 1995, Marshall et al. 2000). The sex ratio topic.Bjomn andReiser (1991) reviewed unpub- observedfor spawnersat this hatcherybctween lished data that clearly showedthe potential for' 1988and 1996 averaged 0.7 females to L0 mdes o\ere\timalingreJd \'apreil) $hen :pJu ningirrca (Mendelet al. 1992,1996). We useda 1.0to 1.0 wasbased solely on spawningsubstrate availability. ratio to simplify our analysis,and to add a mea- They concludedthat redd capacitydepended on: \ureol con\er\ati\mlo uur reddr'lprcitl e.ti- the amount of suitablespawning substratecov mates. eredby water with acceptabledepths and veloci- We expandedthe measurementstaken at 12 ties lbr spawning (i.e., spawning area), and on spawningsites to all 106 spawningsites, thereby the arearequired for a pair of spawningfish (i.e.. assumingthat redd capacityof study sitesrepre- spawning-area-per-redd). sentedredd capacity ofnon-study sites. We sanpled We modified the InstrcamFlow Incremental approrimatelyl0' , of theknown spuwning sites. Methodology(Bovee 1982) to estimatespawn- which we believerepresented the spawninghabitat ing area.Although widely appliedby biologists. at non-studysites. Howevel rcdd capacitywithin thir methodcan grossll o\erestimatespa\\ nin[: studysites was variable as shown by the relatively area(Shrivell 1989). Using Shrivell(1989) fbr wide 957c contldence intervals on our redd ca- guidance, we made conservative estimates of pacity estimates.We recomrnendstudying addi- spawningarea by; 1) studyingsites known to be tional sitesif t'uturcrcsearch opponunities become rusedby spauner': 2) calculatingspuwning urea available. basedon the actualshape ofthe wetted spawning We did not measurefactors affecting redd subsfate patchrather than the rectangularshape capacitysuch as inter-gravel flow (Bumer 1951, ofcells;and,3) determining cell lengthusing the Geist and Dauble 1998,Geist 2000). substrate locationofredds or shoft stretchesofhabitat with movement,or substraterecruitment. We assumed relatively homogenousdepths, velocities, substrate, that inter-gravelflow would not limit reddcapacity and channelcontou$. orcausevariability in reddcapacity between sites We used a relatively large value for spawn- with the sameamount ofmodeled spawningarea. ing-area-per-redd(i.e.,70 m'?) that was based on We also assumedthat substratemovement and the highestredd densitywe observed.The space recruitmentwere in dynamic equilibrium. These requiredfor redd constructionprobably va es in are sffong assumptionsthat should be testedin responsetostream size, spawn timing, and spawner the future at both the spatialand temporalscales. density.For comparison.Swan (1989) reported We did not repofi redd capacityestimates for spatial requirementsranging fiorn 21.1 to 15.2 extremellow conditions becausedata were not mr/redd.Bumer ( 1951)proposed that f'emaletali rrailableto [it thestage-discharge reFres\i,'n re- chinook salmonrequire four times the areaof a quired to run IFG-,I. Within the range of flows redd to spawn,which equatesto 68 m' using the modeled,we found that redd capacitydecreased redd surfacearea of 17 m: reportedby Chapman moderatelyin the lower reachofthe Snlke River et al. (1986).Using 70 m':addedan additional

SalmonRedd Capacity 369 measureofconservatism to our estimatesof redd reddcapacity could be aslow as 1,007to l,l,+9. capacity. A stock-recruitmentanalysis (Ricker 1975)con- We developedour methodfor estimatingredd ductedwith empirical data collectedas spawner capacity to accomplishtwo objectives.The re- escapementincreases will b(] the only way to sults obtainedfor the first objectiveindicate that confirm redd capacity, and to determine if the redd capacityfor the upper and lower reachesof recoverygoal is achievable.Otherrecovery mea- the SnakeRiver rangestiom 2,466to 2,570un- suressuch as spawning gravel enlancement might der thc stableflow regime. The actual carrying be necessaryifrecruitment efliciency is atl'ected capacityof theSnake River tbr tall chinooksalmon by densitydependent factors before the recovery rcdds (or the "best estimate") might be higher goal is attained. becauseour methodwas conseruative. For example, the estin.utesof reddcapacity would haveranged Acknowledgements lrom 7.b75lo E.28.ril u e divided'pru ningarea Many employeesof the U. S. Fish and Wildlife ( by the 2l .7 m: per reddreported by Swan 1989) Service'sIdaho Fishery ResourceOffice and the lnsteSoc)] /t, m'- Company collected and processed lvanagementlmp cations data.R. Taylor ofthe U.S. ForestService was the project'sprofessional surveyor D. Geistcollabo- In light of our redd capacity estimates,we be- ratedon earlydrafts. T. Budon andan anonymous lieve that the SnakeRiver can suppoftthe 1,250 reviewer improved the manuscript.Funding was reddsneeded to removeSnake River fall chinook provided by the U. S. Fish and Wildlife Service salmon from the list of federally protectedspe- Lower SnakeRiver CompensationPlan and by the cies. The lowest of the three estimates,2.466, is rate payersof the BonnevillePower Administra- roughlytwice thedelisting criteriaof 1,250redds. tion throughContracts DE-AI79-918P21708 and We acknowledgethat the 957. lower confidence DE-AC06-76RLO1830 administeredby D. limits on our redd capacity estimatesshow that Dochety. M. Galloway, M. Beeman,and K. Tiffan.

LiteratureCited Dauble,D.D.. andD. R. Geist.20{10.Comparison ot mamslem spawninghabilats tbr two populationsof fall chjnook tsJo-nn.I C.. i,rJ D. W R(i.(r. laal Hdbirdrrcquircmenl' salmonjn the Columbia River Basin. RegulatedRiv- ofsalmonidsin streams.Influences offoresr andmnge' ers: Rese ch and Management16:345 361. land nranagemenlon salmonid tishes and their habi- callagher. S. P. and M. F Gard. 1999.Relationship between tats.American Fishefies Society SpecialPublicalion chinook salmon (Oncorh\n(tus tr,'rdx)tr.hd) redd 19r81138. densiljcsand PHABSIM-predictedhabitat in the Bovee. K. D. 1982.A guidc 10strcam habitat analysisusing Merced and LowerAmerican Rivcrs. Calilbmia. Ca the InstfeamFlow IncrenentalMclhodology. Insiream nadian Journal of Fisher;es and Aquatic Sciences Flow Paper 12. U. S. Fish and wildlife Service.01: 56:510-5'7'7. fice ofBiological Services.FWS/OBS E2l26. Carcia,A. P. R. D. waitt. C. A. Larsen,D. Burum. B. D. Bo!ee,K. D.. andR. Milhous.1978. Hydraulic simulation in Amsberg.M. Key. andP A. Grcves.2001. Fail chincx)k instreamflow srudies:Theory and technjques.U. S. salnon spawningground surveysin lhc SnakcRivcr Fish and wildlife Service,Instream Flow Croup ln basin upri!cr of , 2000. Unpub- lbrmadon Papcr Number 5. Fort Collins, Colorado. lished repo( on file alU. S. Fish and Wildlile Ser Bovee,K. D.. andBa(bolo$. J. \'1. I995. IFlM phaseIII study vice.ldaho FisheryResource Office, Ahsanka.Idaho. R '000. Hypo'heicdi'charpe ot r'\er warer;nro implementation.Pages 191 2551, K. D. Bovee (edi- C.r.r. D. fall chinook salmon I oncofi hus tshdw ha) tor). A Comprehensile Review of the Insream Flow !-nc )-tsc spawnine dreasin the H.nfbrd Reach, Columbia River IncrementalMethodology. U. S. Ccological Survey. CanadianJoumal of Fisheriesand Aquatic Sciences National Biological Sen'ice. FoI1Collins, Colorado. 57:1647-1656. Buget R., C. w Hople), C. Busack. and G. Mendel. 1995. Geist,D. R., andD. D. Dauble. 1998.Redd site selectionand Maintenanceof stock integrity ir Snake Rivcl fall spawninghabitat use by fallchinook salmon:The im- FisheriesSociety Sympo- chinook salmon.American porlancc of gcomorphic featuresjn large ivers. En- sium 15:267276. \ ifurmeflJl \'lJnrg

370 Connor et al. Grovcs. g A., and A. P Garcia. 1998. Two carners useclto Salmon.Unpublj shed repoft on file at WashingtonI)e suspendan underi'ater canera liom a boal North partmeniof Fish dndWildllfe. SnakeRivet Lab. Day AmericanJoumalof FisheriesManagemenll8:1004- lon. Washington- l007. Nlilhous,R.t. D. L. wegner.and T.W \\/addlc. ]9it,l. User's Crovcs. P A., andJ. A. Ch:urdler 1999.Spawning habilatused guide to thc physical habitat simulation sy\tcm. b) lall chinook salmon in fte Snakc River. North lnstreanflow inlbm1ationpaperNumber I L Lr.S.Fish Ameficrn Jounal of FjsheriesMaragel1lenl 19t912_ and Wildlife Sen'ice FWS/OBS 8l/43. 922. National Mafine FisheriesSc ice. 1992.Threatened status Kondolf. G. M., J. C. Vick. and T. M. Ranlirez. 1996.Salmon lbr SnakeRiverspring/sunmerchinook salnron, thrcat- spawninghabrtat rehabilitadon on the Merced River. enedstatus ibr SnakcRiverfallchinook salmon.Fed Califomia: an cvaluatjonof project planning and per- cral Register57:78(22 April 1992):I 1,653-1,1,663. fonnance.Transacdons ofthe Amefican FisheriesSo National Marinc FisheriesService. 1995. Proposcd recovery ciety 125:899-912. plan for SnakeRi\er salmon.Unpublished repo( on Krebs. C. J. 1999. Ecological Merhodology (2nd edition). file at U.S. Depa mcnt of Commerce.Natioral Addison-wesleyEducational Publishers. Incorporatcd. oceanographicand AtmosphericAdministratjon, Pon- Mcnlo Park, Califbmia. land,. Marshall, A. R.. H. L. Blankenship.and $'. P Connor.2000. Ricker, W E. 1975.Computrtion and lnlcryrctaljon of Bio- Ccnctic characterizationof naturally spa* ned Snale logicalSrxristics. Bulletin l9l ofthe FisheriesRc River lall run chinook salmon. Transactionsof the .c"rch tso,rdnf{ "nuJr Olla$a.OnrJi^. AmericanFisheries Socicty 129:680-698. Shrivell. C. S. 1989.Ability of PHABSIM |o prcdict chinook Mendel. G.. D. Milks. R. Bugerl, and K. Pelersen-1992. Up salmonspawning habitar. Regulated Riveft : Rescarch strean passageand spawningC)l 1a1l chinook salmon and Management3:277 289. in the SnakeRivcr. 1991.Unpublished report on file Swan.C. A. I 989. Chinook salmonspawning sun'eys in deep at washingtonDepartnentofFish andWildlife. Snale $,atersof a largc regulatedriver Regulaled Rivcrsi River Lab. Dayton. Washington. Researchand Managenenl ,{13553?0. Mendel.C.. J. Bumg.rrner,D. Milks, L. Ross,J.Dedlofi. 1996. Wunderluch,R. C., B. D. winter. andJ. H. Meler. 199,1.Rcs Lyons Ferr-vHalchery Evaluadon:Fall Chinook toration ofihe Elwha Rivcr ccosyslem.Fisheries 19: 11 19. Received6 February'2001 Ac.eptedfor publication l5 June 2001

SalmonRedd Capacity 371