SK361.U54no. 82-10.1 22

LibraryNaltonal w~tta"ct. Rlleareb CenterU. S. Fish and WUdilie service700 CaJundomt Boulevardliaf.,etteJ La: 70&01

BIOLOGICAL REPORT 82(10.122)SEPTEMBER 1986

HABITAT SUITABILITY INDEX MODELSAND INSTREAM FLOW SUITABILITYCURVES: CHINOOK SALMON

....:_., and Wildlife Service

. Department of the Interior

MODEL EVALUATION FORM

Habitat models are designed for a wide variety of planning applica-tions where habitat information is an important consideration in thedecision process. However, it is impossible to develop a model thatperforms equally well in all situations. Assistance from users andresearchers is an important part of the model improvement process. Eachmodel is published individually to facilitate updating and reprinting asnew i nformat i on becomes avail ab 1e. User feedback on model performancewill assist in improving habitat models for future applications. Pleasecomplete this form following application or review of the model. Feelfree to include additional information that may be of use to either amodel developer or model user. We also would appreciate information onmodel testing, modification, and application, as well as copies of modifiedmodels or test results. Please return this form to:

Habitat Evaluation Procedures Groupor

Instream Flow GroupU.S. Fish and Wildlife Service2627 Redwing Road, Creekside OneFort Collins, CO 80526-2899

Thank you for your assistance.

Species _

Habitat or Cover Type(s)

GeographicLocation

Type of Application: Impact Analysis Management Action Analysis __Baseline Other -------------------------

Variables Measured or Evaluated

Was the species information useful and accurate? Yes No

If not, what corrections or improvements are needed?----------

Were the variables and curves clearly defined and useful? Yes No

If not, how were or could they be improved?

Were the techniques suggested for collection of field data:Appropriate? Yes NoClearly defined? Yes NoEasily applied? Yes No

If not, what other data collection techniques are needed?

Were the model equations logical? Yes NoAppropriate? Yes No

How were or could they be improved?

Other suggestions for modification or improvement (attach curves,equations, graphs, or other appropriate information)

Additional references or information that should be included in the model:

Model Evaluator or Reviewer Date------------

Agency _

Address -------------------------------

Telephone Number Comm:----------- FTS _

Biological Report 82(10.122)September 1986

HABITAT SUITABILITY INDEX MODELS AND INSTREAM FLOWSUITABILITY CURVES: CHINOOK SALMON

by

Robert F. RaleighP.O. Box 625

Council, 10 83612

William J. Miller1244 S. Bryan

Fort Collins, CO 80521

and

Patrick C. NelsonInstream Flow and Aquatic Systems Group

National Ecology CenterU.S. Fish and Wildlife Service

2627 Redwing RoadFort Collins, CO 80526-2899

Performed forNational Ecology Center

Division of Wildlife and Contaminant ResearchFish and Wildlife Service

U.S. Department of the InteriorWashington, DC 20240

This report should be cited as:

Raleigh, R. F., W. J. Miller, and P. C. Nelson. 1986. Habitat suitabilityindex models and instream flow suitability curves: chinook salmon. U.S.Fish Wildl. Servo Biol. Rep. 82(10.122). 64 pp.

PREFACE

Information presented in this document is for use with the HabitatEvaluation Procedures (HEP) and the Instream Flow Incremental Methodology(IFIM). The information also should be useful for impact assessment and fordeveloping management recommendations and mitigation alternatives for thespecies using methodologies other than HEP or IFIM. The comparison andrecommendations for use of HEP and IFIM presented by Armour et al. (1984)1should help potential users of these two methodologies determine the mostefficient way to utilize the information in this publication.

The Suitability Index (S1) curves and graphs and Habitat SuitabilityIndex (HSI) models presented in this report are based primarily on a synthesisof information obtained from a review of the literature concerning the habitatrequirements of the species. The HSI models and SI curves are scaled toproduce an index between 0 (unsuitable habitat) and 1 (optimal habitat).Assumptions used to transform habitat use information into an index are noted,and guidel ines for appl ication of the curves and model s are described. Adiscussion of IFIM and chinook salmon SI curves available for use with IFIM isincluded.

The SI curves and HSI models are starting points for users of HEP or IFIMto develop their own curves and models. Use of the SI curves and HSI modelswithin project-specific applicational constraints is likely to require modifi-cation of the SI curves or graphs and HSI models to meet those constraints andto be applicable to local habitat conditions. Users of the SI graphs and/orHSI models with HEP should be familiar with the standards for developing HSImodels (U.S. Fish and Wildlife Service 1981)1 and the guidelines for simplify-ing HSI models and recommended measurement techniques for model variables(Terrell et al. 1982; Hamilton and Bergersen 1984).1 Users of the SI curveswith IFIM should be familiar with the Guide to Stream Habitat Analysis (Bovee1982)1 and the User's Guide to the Physical Habitat Simulation System (Milhouset a1. 1984). 1

The HSI models and SI curves are hypotheses of species-habitat relation-ships, not statements of proven cause and effect relationships. The curvesand model s are based on the 1iterature and professional judgment. They havenot been applied "in the field. For this reason, the U.S. Fish and Wildlife

lCitation included in References.

iii

Service encourages model users to convey comments and suggestions that mayhelp us increase the utility and effectiveness of this habitat-based approachto fisheries planning. Please send comments to:

Habitat Evaluation Procedures Group

or

Instream Flow and Aquatic Systems GroupNational Ecology CenterU.S. Fish and.Wildlife Service2627 Redwing RoadFort Collins, CO 80526-2899

iv

CONTENTS

Page

PREFACE _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iiiFIGURES viACKNOWLEDGMENTS vi i i

INTRODUCTION 1HABITAT USE INFORMATION (HSI Model) 2

General Distribution and Life Cycle. 2Specific Habitat Requirements, Sources, and Assumptions.... 4

HABITAT SUITABILITY INDEX (HSI) MODELS .. 11Suitability Index (SI) Graphs for Model Variables ,. 11HSI Mode 1 App 1i cabi 1ity 22Model Description.................................................... 22Model 1, Limiting Factor............................................. 25Model 2, Compensatory Limiting Factor.... 25

INSTREAM FLOW INCREMENTAL METHODOLOGY (IFIM) 29Suitability Index Curves as Used in IFIM 30Availability of SI Curves for Use in IFIM 30Spawni ng mi grat ion 51Spawning and Egg Incubation.......................................... 51Fry 55Juvenile............................................................. 56

REFERENCES 57

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Number

1

2

3

4

5

6

7

8

9

10

11

12

13

FIGURES

Diagram illustrating the relationship among model variables,components, and HSI .

Category one SI curves for chinook salmon passage depth andtemperature suitability .

Category two SI curves for migrating chinook salmon spawners;velocity and depth utilization during migration holding .

SI curves for spawning/egg incubation velocity and depth, foreffective spawning habitat analysis .

Category one SI curves for chinook salmon spawning, eggincubation, and intergravel fry velocity, depth, substrate,percent fi nes, and temperature suitabil ity ..

Category one S1 curves for chinook salmon fry velocity, depth,and temperature sui tabi 1i ty .

Category one S1 curves for chinook salmon juvenile velocity,depth, and temperature suitability .

Category two SI curves for spring chinook salmon spawningvelocity and depth utilization (n = 252) .

Category two SI curves for fall chinook salmon spawningvelocity and depth utilization (n = 107) .

Category two S1 curves for fall chinook salmon spawningvelocity and depth utilization (n = 216) .

Category two S1 curves for spring chinook salmon spawningvelocity and depth utilization (n = 118) '" .SI curves for chinook salmon spawning velocity (category two)and de pt h (c ate gory 0 ne), (n ::: 265) .

Category two S1 curves for chinook salmon spawning velocityand depth utilization (n = 436) .

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34

36

37

38

39

40

41

42

43

Number

14

15

16

17

18

19

FIGURES (Concluded)

Category two SI curves for chinook salmon fry velocity anddepth util ization (n = 202) .

Category two SI curves for chinook salmon fry velocity andsubstrate utilization .

Category one SI curves for chinook salmon fry velocity anddepth suitabi 1ity .

Category two SI curves for chinook salmon juvenile velocity,depth, percent cover, and cover type utilization .

Category two SI curves for chinook salmon juvenile velocityand substrate utilization .

Category one SI curves for chinook salmon juvenile velocityand depth sui tabi 1i ty .

vii

44

45

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49

50

ACKNOWLEDGMENTS

We gratefully acknowledge R. Behnke, Colorado State University, T. Bjorn,Idaho Cooperative .Fishery Research Unit, F. Everest, Pacific Northwest ResearchStation, M. Healey, R. Lauzier, W. Knopp, S. Samis, C. Clarke, andS. Macdonald, Canada Department of Fisheries and Oceans, G. Hartman, PacificBiological Station, Nanaimo, B. C., A. Lowes Blackwell, University of Texas atArlington, and M. Odemar, California Department of Fish and Game, for reviewcomments which improved the quality and accuracy of this report. The readershould not construe reviewer assistance as an endorsment of the SuitabilityIndex curves or the habitat model. The initial literature reviews wereconducted by the Alaska Department of Fish and Game personnel, and T. Tatom.J. Zuboy provided editorial assistance and C. Solomon coordinated the reviewsand manuscript production. Word processing was by E. Barstow, P. Gillis, andD. Ibarra. The cover figure is from Freshwater Fishes of Canada, Bulletin184, Fisheries Research Board of Canada, by W. B. Scott and E. J. Crossman.

vii i

CHINOOK SALMON (Oncorhynchus tshawytscha)

INTRODUCTION

This publication contains habitat models constructed and informationcompiled for two distinctly different purposes. The Habitat Suitability Index(HSI) model by Raleigh and Miller contains 17 habitat variables for chinooksalmon by life stage. The HSI model provides an objective quantifiable methodof assessing the existing habitat conditions for chinook salmon within a studyarea by measuring how well each habitat variable meets the habitat requirementsof the species by life stage. The model thus provides an objective basis forpredicting probable project impacts, documenting post project impacts, andguiding habitat protection, mitigation, enhancement, and management decisions.

The section by Ne 1son conta ins habi tat cri teri a curves for fi ve flows-related variables for use in the Instream Flow Incremental Methodology (IFIM)(Bovee 1982; Milhouse et al. 1984). The IFIM model is intended to provide anobjective method of assessing the effects of changes in water flow on habitatof chinook salmon by life stage. The HSI model is presented first followed bythe IFIM section. Comments on model assumptions or performance, should beaddressed to the appropriate author of each section. A brief overview of theHSI modeling procedures and IFIM curves follow.

The HSI model was constructed by searching the available technical liter-ature, agency data files, and individual study progress reports for informationon the habitat requirements of chinook salmon. This information was used toderive Suitability Index (SI) graphs for each habitat variable identified fromthe information base. As many habitat variables as were located were includedto enable the user to evaluate a wide variety of habitat conditions useful inevaluating, managing, or improving chinook salmon habitat, or in assessingproject impacts. The HSI model is flexible enough to utilize from one to allof the available variables to suit the needs of the user.

The SI graphs for the HSI model were constructed by quantifying field andlaboratory information on the effect of each habitat variable (e.g., temper-ature, dissolved oxygen, spawning gravel size, siltation) on the growth,survival, or biomass of the species, by life stage. The graphs are based onthe assumption that increments of growth, survival, or biomass plotted on they-axis can be directly converted into an index of suitability from 0.0 to 1.0for the species, with 0.0 indicating unsuitable conditions and 1.0 optimalconditions. Measurements of each habitat variable taken at the proper time inthe field can be applied to the SI graphs to obtain an estimate of thesuitability of the variable in meeting the habitat requirements of the species.

Instream flow SI graphs may be based on literature, professional judgment,lab studies, or field observations of the frequency of use of a habitat

1

variable (e.g., gravel size), within an available range of conditions, byindividuals of a species. The premise with field data is that individual fishwill select and occupy the best habitat conditions available to them. Optimalconditions for a variable are considered to be those conditions under whichmost individuals are observed. Range limits for a variable are the conditionsoutside of which no individuals are observed. The Physical Habitat SimulationSystem (PHABSIM) component of the IFIM uses four variables: water velocity,depth, substrate composition, and cover. Wherever individuals of a speciesare observed in a stream, measurements are taken on the above four variables.In most cases to date SI curves have not been tested for cross-correlationsamong variables, and only univariate curve functions have been developed. Ifmultivariate SI functions are not available for use with IFIM, then eachvariable is treated independently of the others. It is also assumed that afull range of preferred and tolerated variable values were available forselection by individuals of the species at each study stream and datacollection site. If this assumption is not true, bias may occur in thefrequency analysis method, unless habitat availability limitations are factoredout (Bovee 1986).

It is sometimes diffi cult to determi ne if the full range of usableconditions for a particular variable have been included in field and laboratorystudi es. For examp 1e, spawn i ng adul ts may have been observed us i ng gravelranging from 0.3 to 10 cm in size. Studies of the effects of siltation onembryo survival for the species may indicate that the lower limit of 0.3 cmappears acceptable. If different streams had been included in the studies,however, the upper gravel size limit may have been greater than 10 cm.

Laboratory tests used in constructing the HSI model SI graphs can oftenadd more certainty to upper, lower, and optimal suitability values, especiallyfor variables such as temperature, dissolved oxygen, and pH. Both laboratoryand field results, must be considered in 1ight of test conditions, e.g.,acclimation conditions, handling, exposure times, control test results forlaboratory tests, and observation and data collection procedures and conditionsfor fi e 1d studi es. For these reason s, some judgment is often necessary inconstructing SI graphs for both IFIM and HSI models, and some variability mayexist in the shape of the SI graphs.

The data base and SI graphs were reviewed by biologists familiar with theecology of chinook salmon, and suggested changes not at variance with publishedstudy results were incorporated. The user is advised, however, to review eachSI graph to determine how well it represents known regional requirements forthe species. Changes should be made if warranted, but the reasons for eachchange should be fully documented.

HABITAT USE INFORMATION (HSI MODEL)

General Distribution and Life Cycle

The information included in this chinook salmon model is restricted tothe freshwater habitat variables used by prespawning and spawning adults,incubating embryos, preemergent fry, and postemergent juveniles. The oceanhabitat requirements of chinook salmon are not included.

2

Chinook salmon have the most diverse life history of any of the Pacificsalmon. Among the various recognized races of chinook salmon (spring, summer,fall, and winter) there is dtve r s t ty in time of entry into the river systems,time of spawning, distance from the sea of spawning areas, length of freshwaterand ocean residence, and average size and age at maturity. The model containsa synoptic overview of the life history and known freshwater habitat require-ments of each race.

Chinook salmon are the largest in average size of the five species ofPacific salmon. The largest known weight for a chinook salmon is 57.2 kg.Chi nook sa 1mon ra.ngi ng from 6 to 23 kg are common in sport and commerci a1catches.

The original range of chinook salmon in North America was from the VenturaRiver, California, to Point Hope, Alaska, with 13 specimens reported from theCoppermine River about 1,600 km east of Point Barrow, Alaska (Hart 1973; Majoret al. 1978; Behnke 1985). In the Far East, chinooks occur from the AnadyrRiver in the U.S.S.R., southward along the Kamchatka Penninsula and intoHokkaido, Japan (Major et al. 1978; Behnke 1985). Viable populations ofchinook salmon have been established in New Zealand and in the Great Lakes inthe United States. Attempts to establish chinook runs in other parts of theworld have not been successful.

Chinook salmon spawn in about 640 streams along the Pacific Coast of theUnited States and Canada, but major populations are concentrated in only a fewof the larger river systems: the Sacramento, Columbia, Copper, Nushagak,Kuskokwim, and Yukon Rivers in the United States, and about 14 rivers inCanada (Aro and Shepard 1967). Vronskii (1972) attributes more than 90% ofthe U.S.S.R. commercial catch to the Kamchatka River (Major et al. 1978).

As stated earlier, there is a large amount of life history diversitywithin the chinook salmon species. Four races of chinook sal~on are recognizedfrom the Sacramento River system (Erkkila et al. 1950; Hoopaugh 1978; Behnke1985). The fall run enters the Sacramento River in late summer and spawnsfrom 1ate October into December. The eggs overwi nter and the emergent frybegin their seaward migration in the early spring within a few weeks ofhatching. The late fall run enters the river beginning in October, spawningpeaks in February, and seaward migration begins at the time of emergence fromthe gravel. The winter run enters the river in winter and early spring.Spawning begins in April and peaks in May to early June. The fry spend a yearin freshwater before smolting. The spring run enters the river primarily inMay and June, and spawn i ng occurs in September and October. The eggs over-winter and seaward migration occurs in the early spring.

There are three races of chinook salmon in the Columbia River recognizedby their time of entry, time of spawning, and age and time of smolt migration.Spring chinook adults enter the river from February through May, summer chinookJune through August, and fa 11 chi nook from mi d-August through October (Fulton1968; Major et al. 1978). Spawning occurs from late July into December, withthe order of spawning being loosely related to the time of entry into theriver (Fulton 1968).

3

From southern to northern latitudes of the chinook salmon range thereappears to be a tendency for: (1) the number of races to decrease from fourin the Sacramento to three in the Columbia, Fraser, and Nanaimo Rivers, to twoin lower Alaska, to one in northern Alaska rivers; (2) spawning to occurearlier in the year with spawning peaks in late August through October in thesouthern areas and in July and August in the northern portion of the range;(3) length of freshwater residence by juveniles to increase from a fewweeks to 1 year in the southern portion of the range, to an average of 1 to2 years and occasionally 3 years (Meehan and Siniff 1962) in the northernport i on of the range; and (4) average age at spawn i ng to increase from 3 to6 years in California rivers to 5 to 8 years in central to northern Alaskarivers.

Spawning adults may use all available suitable sections over the entireriver system for spawning. Spawning may occur in chinook salmon rivers fromwithin a few miles of saltwater intrusions to as far as 3,000 km upstream fromthe ocean in the Yukon River. Both the mainstem river and tributaries areused by spawning chinook salmon. In general, fall run chinook tend to spawnin larger mainstem rivers and the emergent fry tend to begin their seawardmigrat i on with a few weeks after emergence, whereas spri ng chi nook tend toutilize smaller tributaries and upstream reaches of principal tributaries andthe young spend the first year in freshwater prior to smolting (Raleigh andEbel 1967; Fulton 1968).

Fecundity of chinook salmon varies by size and to some extent by race.In general, fecundity varies from a few thousand to as many as 20,000 eggs perfemale (Vronskii 1972). The demersal eggs are buried in two or more largepockets excavated in the substrate grave 1 by the female. The fert i 1i zed eggsare covered by gravel dislodged upstream of the redd by the female and carrieddownstream by the river current. The length of time from fertilization tohatching varies with average stream temperature, but requires roughly 900 to1,000 thermal units (Seymour 1956). There is one thermal unit for each degreeCelsius above freezing for a 24 hour period. After hatching, the yolk sac frytypically spend several more weeks in the gravel prior to emergence. Emergencefrom the gravel occurs in early spring, generally from February to June,depending on latitude, temperature, and time of spawning. The SacramentoRiver winter chinook run is an exception. Winter chinook spawn in the springand the fry hatch and emerge from the gravel in midsummer.

Specific Habitat Requirements, Sources, and Assumptions

Chinook salmon adults stop feeding when they enter a river to spawn andthey die after spawning. Adult holding habitat in the form of large, deep,pools is important to prespawners, some races of which may spend several weeksin freshwater before spawning. The productive potential of the river systemis not important to the adults, but it is to the juveniles, which may spendfrom a few weeks to as much as 3 years in freshwater pri or to migrat i ng tosea. In addition, juvenile summer and winter rearing habitat is a majorfactor in the survival and production of chinook salmon. The HSI modelincludes the freshwater habitat requirements of all life stages, but is mostconcerned with embryo and juvenile habitat requirements.

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Headwaters of high-gradient, coastal salmonid streams are relativelyunproduct i ve. Most energy inputs to the stream are in the form ofallochthonous materials, such as terrestrial vegetation and terrestrial insects(Idyll 1942; Chapman 1966; Hunt 1971). Aquatic invertebrates are most abundantand diverse in downstream, moderate-gradient riffle areas with rubble substrateand on submerged aquatic vegetation (Hynes 1970; Binns and Eiserman 1979).Optimal substrate for maintenance of a diverse invertebrate population,however, consists of a mosaic of mud, gravel, rubble, and boulders, withrubble dominant. A pool-to-riffle ratio of about 1:1 (approximately a 40% to60% pool area) appears to provide an optimal mix of food-producing and rearingareas for salmonids (Needham 1940). In riffle areas, the presence (>10%) ofcoarse (~3.0 mm) fines reduces the production of invertebrate fauna (adaptedfrom Cordone and Kelly 1961; Crouse et al. 1981). The gradient, watervelocity, and substrate size tend to decrease downstream, whereas the pool toriffle ratio, temperature, productivity, and species diversity tend toincrease.

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials in small to moderate sizedstreams. Too much shade, however, can restrict primary productivity in astream (Chapman and Knudsen 1980). Shading becomes less important as streamgradient and size increase. About 50% to 75% midday shade appears optimal formost small salmonid streams (adapted from Chapman and Knudson 1980, and Oregon/Washington Interagency Wildlife Conference 1979). In addition, a wellvegetated riparian area helps control watershed erosion. The presence offines in riffle-run areas can adversely affect embryo survival, foodproduct ion, and escape cover for juveni 1es. In low to moderate gradi entterra in, a buffer stri p about 30 m wide on each side of the stream, 80% ofwhich is either well vegetated or has stable rocky stream banks, providesadequate erosion control and maintains undercut stream banks characteristic ofgood salmonid habitat.

There is a definite relationship between the annual flow regime and thequality of salmonid riverine habitat. Adequate flows must be maintained tomeet the needs of the developing embryos and yolk sac fry in the gravel, butabnormally low or high flows can be destructive. Significant mortalities tosalmon embryos and yo l k sac fry have been reported due to dessication orfreezing of redds caused by too-low, late fall-winter flows, and from natalgravel movement and downstream displacement of newly emerged fry duringabnormally high freshets (Andrew and Geen 1960). Bustard (1973) listed threemajor factors contributing to overwinter losses of juvenile chinook and cohosalmon and steelhead in the Morice River: (1) stranding and freezing, (2) lowdissolved oxygen, and (3) predation. All three factors were correlated withtoo-low winter flows. An annual base flow ~50% of the average annual dailyflow is considered excellent for salmonid production, a base flow of 25% to50% is considered fair to good, and a base flow of

tailwater salmon and trout habitats can enhance production of chum, coho, andchinook juveniles (Lister and Walker 1966) and trout (Nehring and Anderson1982, 1983), or give a competitive edge to spring or fall spawning stocksdependent upon timing and amplitude of flow releases.

Optimal value and range for pH were not located for chinook salmon.Since chinooks are sympatric with other salmonid species, however, we acceptthe average salmonid pH range of 5.5 to 9.0, with an optimal range of 6.8 to8.0 (Behnke and Zarn 1976), as applicable to chinook salmon.

Adult stage. Chinook salmon enter North American streams to spawn nearlyyear around. With the wide diversity in times and places of spawning it isnot surprising that spawning temperatures also range widely from 4.4 to 18°C(Mattson 1948; Burner 1951), although temperatures >12.8 °C resulted inincreased mortality to females prior to spawning (Andrew and Geen 1960).Spawning and embryo rearing temperatures for winter run chinook salmon arewi thi n the above range, but appear to be more restri ct i ve. Information forwinter run chinook will be reported in the embryo section that follows. Nofurther distinctions in chinook racial spawning requirements for watervelocity, depth, or substrate size will be made in the adult section, sincethese variables appear to be size, not racially, related.

Chambers (1956) stated that the gravel used in constructing the redd mustbe of a size that can be moved by the fish and the current. Therefore, thewater velocity and the maximum size of the spawning gravel utilized is relatedto the size of the fish. Chinook, the largest species of Pacific salmon, tendto use slightly higher water velocities and larger gravel for spawning thanother salmon. Burner (1951) reported that spring chinook redds in the ColumbiaRiver consisted of about 6% fines, 59% to 86% gravel ~15 cm in diameter, and8% to 35% rubble >15 cm; summer chinook redds were about 5% to 8% fines, 85%to 95% gravel ~15 cm, and 0 to 7% rubble >15 cm; and fall chinook redds wereabout 3% to 5% fines, 56% to 89% gravel ~15 cm, and 6% to 41% rubble >15 cm.Summer chinook are smaller in average size (6.4 kg average) than fall chinook(8.2 kg average) in the Columbia River (Fulton 1968). Chambers (1956) listspercentages of gravel sizes for chinook salmon redds of about 21% for 0.3 to1.25 cm; 41% for 1.25 to 6 cm; 24% for 6 to 10 cm; and 14% for 6 to 15 cm.Briggs (1953) gives a mean spawning gravel size of 4.2 cm for chinook salmonin California. Chambers (1956) lists an average size range of 3 to 15 cm forCanadian chinook, and Hobbs (1937) reports that most New Zealand chinook usegravel ~7.7 cm in diameter. An upper size limit on gravel would depend uponthe size of fish and was not reported for chinook salmon; however, sincegravel size of >15 cm composed only 0 to 7% of summer chinook redds, we assumethat spawning gravel 15 cm in diameter may be approaching the upper usablesize limit for average size chinook salmon. Huntington (1985) reported thatthe most heavily used, prime spawning gravel beds of salmon tend to developparallel bands of elevated gravel. Bands 0.6 to 2.4 m amplitude with aperiodicity of 6.0 to 18.0 m have been reported. Huntington (1985) believesthe presence of these bands indicates prime spawning areas for salmon.

McNeil (1968) reported that while coarse bed materials allow better waterflow and oxygen levels in the redds, they also allow better access to eggs andyolk sac fry by predators than smaller gravel sizes. McNeil (1968) attributed

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a 32% greater egg loss from the coarsest gravel areas to probable predation bysculpins. From the above information we conclude that suitable spawninggravel for chinook salmon ranges in size from about 0.3 to 15 cm. The uppersize being dependent upon size of spawner. The optimal size range is estimatedto be about 2 to 10.6 cm.

Water velocity and minimal depth appear to be factors influencing spawn-ing site selection and survival of embryos. Velocity appears to be a majorfactor and mi ni ma 1 depth a secondary factor. Spawn i ng in productive chi nooksalmon streams has been observed at depths of ~0.2 m (Briggs 1953) to ?o7 m(Chambers 1956). Sockeye salmon have been reported spawning in lakes atdepths >21 m (Canada Department of Fisheries 1959). Andrew and Geen (1960),after a 3-year study on the Chilko River, reported that, beyond a minimalfigure, depth per se did not appear to exert a major influence on the selectionof spawning sites, but velocity did. Shallow gravel beds that go dry and areexposed to freezing in the winter were never heavily populated, nor were theythe first choice of spawning salmon. Divinin (1952) observed that when thedistribution of salmon spawners over the spawning grounds was optimum, therewas no spawning in waters shallower than 0.2 m. At high spawner densities,however, salmon have been reported to spawn on sand and silt substrates (Semko1939) and at depths of ~0.1 m (Divinin 1952). Embryo mortalities would likelybe excessive under such extreme conditions. We concl ude that spawni ng ofchi nook sa 1mon can successfully take place over a wide range of depths, butthat depth per se, beyond a minimal level required to protect the embryos fromdrying or freezing, does not significantly affect the selection of spawningsites or the survival of embryos. An acceptable minimal spawning depth forchinook salmon depends upon the amount of flow fluctuation, but in rivers withrelatively stable flow regimes (base flow ?o50% of the average annual dailyflow), we conclude that an acceptable minimal spawning depth for chinooksalmon would be ?oO.2 m.

The major functions of water velocity during spawning and embryo incuba-tion are to: (1) move displaced substrate materials downstream during reddconstruction, (2) carry dissolved O2 to the developing embryos, and (3) remove

metabolic wastes from the redd. Andrew and Geen (1960) list spawning velocityranges of 0.45 to 0.76 m/s for spri ng chi nook and 0.35 to 1.15 m/s for fa 11chinook salmon. Few chinook were observed spawning in velocities >1.15 m/s.Smith (1973) reported mean spawning velocities of 0.43 and 0.50 m/s for springand fall chinook salmon, respectively. In an Idaho stream with uncompactedgravel, a velocity of 0.2 m/s was considered adequate for chinook spawners.Gravel permeability affects the suitability of low velocity levels, whereasfish size, swimming ability, and average substrate size dictate the suitabilityof upper ve 1ocity ranges. From the above i nformat i on we concl ude that theusable spawning and embryo incubation velocity range is about 0.2 to 1.15 m/swith an optimal range of about 0.30 to 0.9 mis, dependent upon gravelpermeabi 1i ty, average substrate size, and average size of spawn i ng adu 1t. Itis conceivable that chinook stocks spawning in colder, northern latitudes mayselect slightly lower velocity water for spawning.

Embryo and yolk sac fry: the intergravel stage. With the exception ofwinter run chinook that spawn in the spring, the developing embryos of spring,summer, and fall runs spend the fall and winter months in the gravel. High

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survival of developing eggs and intergravel yolk sac fry is primarily dependenton the interactions of four variables: temperature, dissolved oxygen, watervelocity, and gravel permeability. Studies have indicated usable ranges andoptimal values for each of the above variables under a variety of conditions,but some judgement is necessary in developing and using the SI graphs developedfor the model. Obviously, lower water velocities are more acceptable withhigher gravel permeability than with low permeability. Also, O2 saturation

and fish metabolism vary with temperature. Thus, as temperatures increase thebiological demand for O2 increases, but the available O2 supply decreases.

The habitat variables of water velocity and spawning gravel particle size werediscussed in the adult section. This section will contain information on theeffects of fines, dissolved O2 , and temperature on survival of chinook embryos.

Burner (1951) observed that chinook salmon redds averaged about 6 m2 insize, and that chinook spawners tend to select areas relatively free of silt,under normal to low spawning densities. When spawning densities are high orsuitable spawning gravel is scarce, however, chinook salmon have been reportedto spawn on sand and silt substrates (Major et a1. 1978). In the KamchatkaRiver, Vronskii (1972) reported that about 95% of the chinook redds werelocated on the gravel transition areas between pools and riffles. He expressedthe opinion that subsurface flows were ideal and the gravels relatively si1t-free in these areas.

It is well known that the presence of fines in redds can impede waterflow and cause impairment of water quality for sa1monid embryos (Cordone andKelly 1961; McNeil 1968). Other studies show that fines can impede theemergence of fry (Koski 1966; Bjornn 1969; Phillips et a1. 1975). The size ofthe fines appears important. McNeil and Ahnell (1964) reported that survivalof pink salmon embryos and intergrave1 yolk sac fry significantly decreased asfines (~0.833 mm) exceeded 5% and approached 15% of the redd particulatematerials. Bjornn (1969) recorded a 28% average survival of stee1head embryosimplanted in a mixture of 30% sand and 70% gravel. Of the 28% that hatched,only 74% emerged. Suitable incubation substrate for chinook embryos appearsto be gravel that is about 0.3 to 15 cm in size that is relatively free offines. Optimal gravel conditions are assumed to include s 5% small fines(~0.8 mm) and 16 °C. Seymour (1956) alsoreported no survival among chinook eggs incubated at a constant temperature of1. 0 °C. Eggs incubated at 12.8 °C for 3.5 weeks and thereafter at 1. 0 °Csuffered only a 3% loss while eggs incubated at 12.8 °C for only 2 weeks and

8

then at 1. 0 °e suffered a 42% mortal ity (Seymour 1956). It appears that aperiod of incubation >2 but ~3.5 weeks at temperatures ~4.5 °C but ~12.8 °C isnecessary for good survival of late summer to fall spawned chinook embryos.Winter run chinook from the Sacramento River and any spring spawning stocks inthe Great Lakes, however, would spawn in the spring while water temperaturesare increasing. The limited information available indicates that winter runchinook in the Sacramento River system usually spawn at temperatures of about5.9 to 14.2 °C, and that temperature suitability and survival is limited onboth the low and high side of this range (Slater 1963). We assume that thistemperature data would also apply to any spring spawners in the Great Lakes.

Survival of chinook eggs from fertilization to fry emergence ranged from90% to 100% at constant O2 concentrations of 3.5, 5.0, 7.3, and 10.5 mg/l at a

water temperature of 10.5 °C. Survival dropped to 0 at a constant temperatureof 15 °e (Eddy 1972). From these temperature data (here and above) it appearsthat a temperature ~15 °e may be 1etha 1 to chi nook embryos. Eddy (1972) a1soreported that embryo to fry survival was highest at 10.5 mg/l O2 and lowest at

3.5 mg/l for all temperatures tested (10.5, 12.0, 13.5, and 15.0). Gangmarkand Bakkala (1960) found that survival of chinook salmon embryos in a coldstream (4 to 9 °e) was highest at O2 concentrations of 13 mg/l and lowest at

5 mg/l. The greatest increase in survival occurred between 5 and 7 mg/l. Inanother study, mean length of sac fry was greatest at 11.7 mg/l O2 and least

at 2.5 mg/l. These tests were conducted at a temperature of 11 °C (Silveret al. 1963). Davis (1975), after reviewing the dissolved O2 requirements for

several Canadian fishes, suggested a minimum concentration of 8 mg/l fordeveloping salmonid embryos. From the above we conclude that the lower limitof O2 concentration for survival with short term exposures is ~2.5 mg/l at

water temperatures ~7 °e with optimal levels of ~8 mg/l at temperatures ~7 but~10 °e and ~12 mg/l at temperatures >10 °e.

Juvenile stream resident stage. There are two general freshwater lifehistory patterns for juvenile chinook salmon: (1) juveniles from stocks thatspawn primarily in larger mainstem rivers or close to the ocean and tend tobegin their seaward migration within a few weeks after emergence from thegravel; and (2) juveniles from stocks that spawn in smaller tributary streamsand in more distant upstream areas that tend to spend one or more years in thefreshwater environment before smolting. In North America, both age-at-migration patterns are present in the southern portion of the range, but onlythe second pattern is found in the northern or Alaskan portion (Major et al.1978). Migration for both groups begins in the spring, primarily April throughJune, but the peak of migration occurs later in northern latitudes. Seawardmigration of chinook smolts tends to be nocturnal and near the stream surface(Gauley et al. 1958; Meehan and Siniff 1962; Major and Mighell 1969; Durkinet a1. 1970).

The following synoptic freshwater life history for juveniles that spendone or more years in the freshwater environment is taken from Everest andChapman (1972). Their study was conducted on spring chinook in two tributarystreams in Idaho. Spawning occurs in August and September. The embryos

9

overwi nter in the stream gravel. Fry emerge in March; feed and grow throughthe summer and fall months; re-enter the gravel-rubble substrate in the latefall as temperatures decline 'from 8 to s4 °C; overwinter in the gravel; emergein the spring; and begin the seaward migration in late MaY through early June.From time of egg fertilization until smolting the juvenile chinook spend about14 to 16 months in freshwater. About 50% of that time is spent in a dormantto semidormant condition in the stream substrate during the cold weathermonths. The 7 to 8 months of active stream. life, however, are extremelyimportant. This same pattern would apply to summer chinook juveniles thatspend a year in freshwater prior to smolting. Some variations in timing wouldbe expected due to racial and average temperature differences.

Upon emergence from the gravel, greatest densities of newly emergedchinook were observed by Everest and Chapman (1972) some distance from shoreat depths ~15 cm in pools and eddies at velocities 5% to30% in gravel-rubble areas tend to impair and eventually prevent the use ofthe gravel-rubble substrate for escape and winter cover by juvenile chinooksalmon.

10

In summary, we conclude that young-of-the-year chinook salmon tend toselect water velocities 0 to 60 cm/s with an optimal range of 0 to 40 cm in size, but optimal size substrate for escape and winter cover is10 to 40 ern in diameter. Sand and silt deposits in the 10 to 40 cm sizesubstrate should be ~5% for optimal use; substrate use becomes increasinglymarginal as sand and silt deposits approach and exceed 30%. We estimate that~20% of the stream area with an average water column velocity 10 °e.

HABITAT SUITABILITY INDEX (HSI) MODELS

Suitability Index (SI) Graphs for Model Variables

This section contains SI graphs for 18 chinook salmon riverine habitatvariables. Instructions on where and when to take the habitat measurements toobtain valid SI scores are included with each SI graph. The habitat measure-ments and SI graph construction are based on the premise that extreme, ratherthan average, values of a variable most often limit the productivity of ahabitat. Thus, extreme conditions, such as maximum temperatures and minimumdissolved oxygen levels, are often used in the graphs to derive SI values forthe model. Other premises are discussed in the Habitat Use Informationsection. Instructions for obtaining an HSI score for chinook salmon habitatfrom SIscores are included.

11

Variable 5uitabil ity graphs

....... 1.0VI Annual maximal or minimal

~

:>

pH. Measure during the ......(/") 0.8summer to fall season.Use the measurement with xOJthe lowest 51 value. -0 0.6s::......

~ O.'r-

'r-.0

0.2to~

::3(/") 0.0

5 6 7 8 9 10pH

V2 Maximum temperature duringwarmest periods when adults

1.0or juveniles are present. ........NMeasure at locations where :> \......

\problems may exist. Down- (/") 0.8 \river, migration block x \8areas and stream resident OJ \-0locations. s:: 0.6 \......

\e-, \

A = prespawning adults ~ 0.4'r- \B = juveniles 'r- \

.0 \to 0.2~ \'r-

l::3(/")

0.0a 5 10 15 20 25

DC

V3 Minimum dissolved O2 1eve1 1.0.......during egg and preemergent (Y):>yolk sac fry period, and ......(/") 0.8during periods of occupationby adults and juveniles. xOJ

-0 0.6A. :55 °c s::......B. >5 - :510 °c

~C. >10 °c 0.4'r-'r-.0 0.2to~

'r-::3

(/") 0.0a 3 6 9 12 15

mg/l

12

......... 1.0""'"::>......

V4 Percent pools during the V') 0.8late growing season low xwater period. OJ 0.6"'Cs::......

~ 0.4.,....,....c 0.2rtl.+J.,...:::::l

V') 0.0a 25 50 75 100

%Vs Pool class rating during

the late growing seasonlow flow period. 1.0

LO

A. ~30% of the habitat ::>...... 0.8classified as pools V')is composed of 1st xclass pools. OJ 0.6"'C

B. ~10% but

Third-class pool: Small in area, or shallow, or both. Pool depth andarea are sufficient to provide a low velocity resting area for one to very fewadult chinook. Cover, if pre5ent, is in the form of shade, surface turbulence,or very limited structure. Typical 3rd class pools are wide, shallow areas ofstreams or smaller eddies behind boulders. The entire bottom of the pool maybe visible.

Variables

Maximum or mlnlmumtemperature at beginningand end of first month ofspawning of late summeror fall spawning stocks.Use the temperature thatyields the lowest S1.

Minimum temperature mustremain ~4.5 °c for ~3.5weeks after fertilization.

Suitability graphs

....... 1.0\.0>......V) 0.8........xQJ

0.6-0~......

~ 0.4..........oD 0.2co+oJ.....:::::l

V) 0.00 4 8 12 16 20

DC

*V 7 Maximum or mlnlmum ....... 1.0r--,temperature at beginning >......and end of embryo incuba- V) 0.8tion period. Use the xtemperature that yields QJ

-0 0.6the lowest S1. ~......

*Use for spring spawning ~ 0.4stocks only.

.....

.....oD 0.2co+oJ.....:::::l

V) 0.00 4 8 12 16 20

DC

14

Va Percentage of spawning .-- 1.0gravel in each of two co>-classes: A. 2-10.6 cm ......t/) 0.8B. 0.3-~2, and ~10.6-15 cm. Measure during xQ)or within 30 days after "'0 0.6s::spawning. ......

>,0.4-+J

Record total area (m") of r-gravel in each class. To .0deri v.e an SI score, use the co 0.2-+Jbest substrate (class A)

~

unt i 1 the sample contains t/) 0.0an area equal to 5% of the 0 2 3 4 5entire chinook habitat areasampled. If class B em/secsubstrate must be includedto obtain a 5% sample,derive an arithmetic meanSI score from the twoindividual SI scoresobtained from the graph.

VaSI = SIA + SIB2

V9 Average water column 1.0velocity (cm/s) over O'l>-areas of spawning gravel ......t/) 0.8used by chinook salmonduring period of spawning xQ)and embryo development. "'0 0.6s::Measure only at depths ......~20 cm and at same ~ 0.4location as gravel (Va). r-

.0 0.2co-+J

~t/) 0.0

0 25 50 75 100 125em/sec

15

VlO Average percentage of fines 1.0in spawning gravel in major aspawning areas. Measure :>within 30 days after

......0.8(/)

spawning is over and at xthe same sites as Va. 0.8 to 30 mm

in size (sand). .c: 0.2ro.f-l

::l0.0(/)

0 5 10 15 20 25 30%

V1 1 Average annual base flow 1.0during the late summer towinter low-flow period as :>......a percentage of the average

(/) 0.8

annual da i ly fl ow. For xembryo and preemergent fry

V13 Predominant (~50%) substratetype in riffle-run areas forfood production indicator. --- 1.0Measure in juvenile rearing Mand upstream areas. >......

(/) 0.8A. Rubble or small bou.l ders x

(or aquatic vegetation in OJ 0.6-0spring areas) dominate; c:......limited amounts of gravel, t' 0.4 -large boulders, or slab 'r-rock may be present. 'r-

B. Rubble, gravel, and ..0 0.2t1:lboulders occur in +J'r-roughly equal amounts, :::::l(/) 0.0or gravel or sma 11 A B Cboulders predominant.Fines, large boulders, Substrate Classor slab rock may bepresent in moderatequantities (~25%).

C. Fines, slab rock, orlarge boulders predom-inate. Rubble orgravel are insignificant(~25%) .

V14 Average percentage of ---. 1.0fi nes «3 mm) in riffle- ~run areas. Measure in >...... 0.8juvenile rearing areas (/)during average flow xperiod. OJ 0.6-0

c:......>, 0.4+J

..0 0.2t1:l+J

:::::l 0.0(/)a 10 20 30 40 50

%

17

LO1.0

>......0.8(/)

V15 Leve 1s of late summernitrate-nitrogen (mg/l). xOJ 0.6Measure after -0spawner ~S::die off. ......

>, 0.4+J..............0 0.2n:l+J......::l 0.0(/) ----r- ,

0 .01-.04 .03- .09 .1-.14 .15-.25or or or or

>2.0 .91-2.0 .51-.90 .26-.50

Nitrate-Nitrogen

V16 Percentage of stream areamg/l

providing escape cover. 1.0Measure during 1ate \.0summer-fall average >......

0.8to low flow period (/)at depths ~15 cm and xwith bottom velocities OJ 0.6-0:::;40 cm/s. s::......

>, 0.4+J......»r-

0.2..0n:l+J......::l

0.0(/)0 10 20 30 40 50

%

~ 1.0*V 1 7 Percentage of stream area r--,with 10 to 40 cm average >......sized boulders. Measure (/) 0.8at same time and areas xas V1 6 • OJ 0.6-0

s::......*Use only for juveniles

~ 0.4that overwinter in ......the freshwater. ......

..0 0.2n:l+J»r-

::l(/) 0.0

0 5 10 15 20 25%

18

Table 1. Literature sources and assumptions for chinook salmonsuitability index graphs.

Variable and source

Behnke and Zarn 1976

Mattson 1948Burner 1951Brett 1952Black 1953McAfee 1966Bidgood and Berst 1969Behnke 1986 (review

comment)

Gangmark and Bakkala 1960Eddy 1972Davis 1975Bustard 1983

Needham 1940Hartman 1965Edmundson et al. 1968Lister and Genoe 1970Everest and Chapman 1972Platts 1974

Hartman 1965Edmundson et al. 1968Lister and Genoe 1970Everest and Chapman 1972Platts 1974

Assumptions

We assumed that an acceptable pH rangeand optimal values were similar to othersympatric salmonid species.

Because chinook salmon are often sym-patrie with rainbow-steel head trout,range from coastal areas to elevationsof 1200+ 01, and from California toNorthern Alaska, we assumed they wouldhave a fairly wide temperature tolerancerange, similar to rainbow-steel head, butwith a lower maximum and optimal range.Northern and high elevation stocks mayhave a more restricted range.

Dissolved oxygen concentrations belowminimum levels associated with temperaturethresholds affect the development andsurvival of chinook salmon embryos andjuveniles.

A pool to riffle ratio of about 1:1(about 40%-60% pools) provides an optimalmix of prespawning adult holding area,juvenile cover and resting area, andstream food-producing habitat for chinooksalmon.

Pools differ in their ability to providecover and adequate resting habitat. Poolclasses utilized by prespawning adults,schools of juveniles, and as summer andwinter cover by chinook salmon wereconsidered essential.

19

Table 1. (Continued)

Variable and source Assumptions

Chambers 1956Seymour 1956Gangmark and Bakkala 1960Eddy 1972Brett et al. 1982Behnke (correspondence)

Slater 1963

Hobbs 1937Burner 1951Chambers 1956Fulton 1968McNei 1 1968

Andrew and Geen 1960Smith 1973

Burner 1951Cordone and Kelly 1961McNeil and Ashell 1964Koski 1966McNeil 1968Bjornn 1969Phillips et al. 1975

Andrew and Geen 1960Tennent 1976Binns and Eiserman 1979Wesche 1980Nehring and Anderson

1982, 1983

Lister and Walker 1966Nehring and Anderson 1982,

1983

Temperatures associated with highsurvival of spring spawning stocks wereconsidered optimal. Those associatedwith poor survival were consideredsuboptimal.

Temperatures during the first 3.5 weeksof embryo development associated withhigh embryo survival were assumedoptimal. Temperatures associated withdevelopmental abnormalities and poorsurvival were considered suboptimal.

Gravel size ranges selected for spawningby chinook salmon were used to set thesize range. The optimal size range wasthose gravel sizes associated with thebest permeability, survival of embryos,and emergence of yolk sac fry.

Average water column velocities selectedby spawning adult chinook salmon andassociated with high survival of embryoswere considered in selecting velocityranges and optimal values.

The percentages of fines in spawninggravel areas associated with high embryosurvival and emergence of yolk sac frywere considered optimal. Suitabilitydecreased as the percent fines andembryo mortality increased.

Base flows as a percentage of the averageannual daily flows that were associatedwith high embryo survival and high standingcrops of juvenile salmonids were con-sidered optimal.

Average annual peak flows as a multipleof the average annual daily flows thatwere associated with high embryo survivaland high standing crops of salmonidswere considered optimal.

20

Table 1. (Concluded)

Variable and source Assumptions

Hynes 1970Binns and Eiserman 1979

Cordone and Kelly 1961Crouse et al. 1981

Binns and Eiserman 1979

Hartman 1965Everest 1969Platts 1974

Hartman 1965Everest 1969Chapman and Bjornn 1969Everest and Chapman 1972

The predominant substrate type containingthe greatest numbers and kinds of aquaticinsects was considered optimal.

The percentage of fines in riffle-runareas associated with the highest stand-ing crops of aquatic food organisms wasconsidered optimal.

Nitrate nitrogen levels in rivers thatare associated with the highest standingcrops of aquatic food organisms andfishes are considered optimal.

The percentage of instream and bank coverin juvenile rearing areas associated withthe highest standing crops of juvenilesare optimal.

The size range of substrate selected mostoften by juvenile chinook as escape andwinter cover was considered optimal.Percentages needed were estimated.

21

HS1 Model Applicability

Geographic area. The following models are applicable over the entireNorth American freshwater geographic range of chinook salmon.

Season. The models rate the freshwater habitat of chinook salmon byseason of occupation for each model component: prespawning and spawningadult, intergravel embryo and yolk sac fry, and stream resident juvenile.

Cover types. The models are applicable to freshwater riverine habitat.

Minimum habitat area. Minimum habitat area is the minimum area ofcontiguous habitat that is required by a species to live and reproduce.Because chinook salmon can travel considerable distances to spawn or locatesuitable summer or winter rearing habitat, no attempt has been made to definea minimum amount of habitat for the species, except that spawning adults oftenutilize about 6 m2 of spawning gravel with a minimum width of 1 m.

Verification level. An acceptable level of performance for this chinooksalmon model is for it to produce variable SI scores between 0 and 1 that theauthor and other biologists familiar with chinook salmon ecology believe ispositively correlated with the habitat requirements of chinook salmon for eachvariable. Model verification consisted of observing the model outputs fromsample data sets developed by the author and model review by chinook salmonexperts.

Model Description

The chinook salmon HS1 model consists of three components: spawningadults (CA), developing embryos (CE), and stream resident juveniles (CJ ) .

Each component contains variables specifically related to that component.

Two models are presented. The first model uses a simple limiting factortheory. The model assumption is that all variables can have a significanteffect on chinook salmon survival and production, and that the high SI scoresof one or more variables cannot compensate for low SI scores of other modelvariables.

The second model uses a partial compensatory limiting factor theory.This method assumes that some compensation can occur among dependent variables,such as water velocity, spawning gravel size, and percent fines.

Adult component. Variables pH (V 1 ) , maximum temperature (V 2 ) , minimum

dissolved oxygen (V 3 ) , percent pools (V 4 ) , and pool class (V s ) affect the

ability of chinook salmon adults to enter the spawning streams, to findsuitable holding habitat until time to spawn, and to survive and spawn success-fully in freshwater, riverine habitats.

22

Embryo component. Variables minimum dissolved oxygen (V3 ) , maximum or

minimum temperature (V6 or V7 ) , average spawning gravel size (Va), average

water column velocity (Vg ) , percent fines (Vi O), average base flow (Vii), and

average peak flow (V1 2 ) all affect the ability of the developing embryos and

intergravel yolk sac fry to develop, hatch, and emerge from the gravel success-fully.

Juvenile component. Variables pH (Vi), maximum temperature (V2 ) , and

minimum dissolved oxygen (V3 ) are water quality variables that directly affect

the ability of the juveniles to survive in the riverine environment. Variablespercent pools (V4 ) , pool class (Vs ), average base flow (Vll ), average peak

flow (V12 ), percent riffle-run fines (V14 ), percent cover (V1 6 ) , and percent

substrate cover (V1 7 ), all affect the quantity and quality of the juvenile

rearing habitat. Variables substrate class (V1 3 ) , percent riffle-run fines

(V1 4 ) , and nitrate-nitrogen concentration (ViS) are indicators of stream

productivity and food supply necessary to sustain juvenile chinook stocksduring the period of freshwater residence.

Model Use and Interpretation

The primary purposes of aquatic HSI models are to: (1) provide reliableinformation on the known habitat requirements of a species by 1ife stage,(2) provide an extensive list of specific habitat variables for a speciesalong with brief instructions on when and where to measure them, (3) providean objective method of estimating how well specific habitat variables meet thehabitat requirements of a species by life stage, and (4) thus, provide anobjective, measurable basis for predicting or documenting project impacts,guiding habitat management decisions, and habitat improvement procedures.

The field measurements of variables for HSI models can be as simple asfoot surveys and ocular estimates over small study sections, or as complex anddetailed as frequent transects using measuring tapes, velocity meters, andsubstrate screens over the entire range of the species in a river system. Theimportance of the decisions to be made, along with time and financial con-straints, will dictate methods selected. The information derived is limit,edby the accuracy of the sampling methods and to the area sampled.

In practice, the habitat variables are measured in the selected studyarea. The data collected for each variable are compiled and analyzed, SIscores derived by use of the SI graphs provided, and the information arrangedin a matrix similar to Table 2. This will provide quantified information onthe relative condition of the habitat from which habitat management decisionscan be made. For project impact analysis purposes, habitat variable measure-ments should be done prior to project initiation to document existing habitatconditions and as a basis for projecting probable project impacts. Suchinformation is extremely valuable in negotiating project design features andconditions and timing of construction phases. The habitat variables aremeasured again after construction is completed to document changes in specific

23

habitat variable suitabilities to guide post project mitigation and habitatenhancement efforts.

For project impact analysis purposes it is often sufficient to measurethe selected habitat variables only in the project impact area. For speciesmanagement purposes, however, it may be desirable to collect habitat data overthe entire range of the species within a river system. For example,individuals may move for considerable distances within the drainageto locate suitable spawning, rearing, or overwintering habitat. Hence, thelack of such habitat within anyone study section would not necessarily meanthat it is in sho~t supply or species limiting. The habitat character of theentire range of the species in the drainage system would have to be consideredbefore this kind of decision would be warranted. The user must be judiciousin interpreting the outputs of the model.

We believe that the data base and S1 graphs are reasonably accurate. Wehave done a fairly thorough job of reviewing the currently available database, and the model has received excellent peer review. The individualvariable S1 scores can be reasonably relied on to indicate the relativesuitability of each variable in meeting the habitat requirements of thespeci es, if the habitat measurments were correctly taken. We recogn i ze thecorrelation between habitat condition and stock density, but past attempts toproduce HS1 model equations that yielded 1He stage or species HS1 scorescorrelated with stock density have not been successful. Tests of the cutthroattrout model HS1 against cutthroat trout stocks in Yellowstone Park streamsyielded a correlation coefficient of 0.37. Goertler, Wesche, and Hubert(1985) tested an early brown trout HS1 model score against brown trout stocksin 10 Wyoming streams. They found that using all 19 of the brown troutvariables in model equations only accounted for 10% of the variation in browntrout population size in the test streams. They produced a three variablemodel that accounted for 63% of the variations in brown trout standing stocks.Models that estimate standing stocks of fishes are useful management tools.Such models typically use a minimum number of variables identified byregression analysis as accounting for significant percentages of variabilityin stock size. Models with a limited number of variables have limited useful-ness in evaluating a wide variety of possible project impacts. We provideguidance on how to derive life stage and species HS1 scores for chinook salmon.We assume that there is some correlation between species HS1 scores and popula-tion size, especially when carefully selected key variables are used. Teststo date, however, using the whole array of variables, have indicated onlyweak, insignificant correlations.

The aquatic HS1 models are not intended to be standing stock predictivemodels. They are models offering the user a maximum number of habitatvariables for a species, which are useful in providing an objective method ofassessing a wide variety of project impacts and in guiding managementdecisions. We advise the use of the individual variable S1 scores rather thanlife stage or species HS1 scores as the most reliable guides in this process.

24

Table 2 displays hypothetical data sets for each chinook habitat variableand 51 scores derived for these data from the appropriate suitability indexgraphs. Table 2, Figure 1, and the preceding life stage discussions in thenarrative section indicate the relationships among model habitat variables andchinook salmon freshwater life stages. A single H51 score can be obtained forthe species or for any life stage in the sample area as desired by the user.We suggest selecting the lowest 51 score of key variables as the species orlife stage H51 (Table 2).

Modell, Limiting Factor

The limiting factor model assumes that each variable in the model cansignificantly affect the ability of the habitat to produce chinook salmon;therefore, high 51 values in some variables cannot compensate for low 51values in other variables and, hence, the species H51 cannot exceed the lowest51 value for any variable. The limiting factor model yields component 51scores of 0.7 for adults, 0.5 for embryos, and 0.6 for juveniles with a speciesH51 of 0.5 for the habitat represented by the 51 values shown in Table 2.

Model 2, Compensatory Limiting Factor

The compensatory limiting factor model also assumes that each variablecan significantly affect the ability of the habitat to produce chinook salmon.This model, however, assumes that low 51 scores of dependent variables can bepartially compensated for by high 51 scores of other dependent variables inthe set. An 51 score ~0.3 cannot be compensated for. Two examples using thecompensatory limiting factor model follow:

1. Adult and juvenile components. It is assumed that the variablespercent pools (V 4 ) and pool class (Vs ) are dependent and compensatory

in their effect on chinook salmon habitat suitability (V 4 = 0.7,

Vs = 1.0, Table 2).

07+ 1 0Lowest 51 = .' 2 . = 0.85

The percent pool variable (V 4 ) 51 for both adults and juveniles

would increase from 0.7 to 0.85. The adult component 51 would nowbe dissolved oxygen limited so the adult component 51 score (lowest)would now be 0.8.

The juvenile component 51 would still be limited by V1 2 and V1 3 and

would remain 0.6.

The species H51 would not change since the embryo component 51 scoreis still the lowest component 51 score.

25

Table 2. Suitability indices (SI) scores for chinook salmon

habitat variables by life stage. a

Adul t Embryo Juvenile

Variables Data SI Data SI Data SI

V1 pH 6.8 1.0 6.8 1.0

V2 Maximum temperature (OC) 19°C 0.82 19 °C 0.82

V3 Minimum dissolved oxygenO2 (mg/l) lOB 0.8 9A 1.0 lOB 0.8

V,. % pools 30 0.7 30 0.7

Vs Pool class A 1.0 A 1.0

V6 Maximum temperature(embryo) 8.0 1.0

V7 Maximum or minimumtemperature

(embryo)b

Va Average substrate size(embryo) 1.5 0.5

Vg Average velocity(embryo) 40 1.0

VlO % fines (embryo) 12B 0.9

Vll Average base flowc 40 0.8 40 0.8

V12 Average peak flowc 1.5 1.0 3.5 0.6

Vl3 Substrate class B 0.6

V14 % riffle-run fines 8 1.0

V15 Nitrate-N concentration 0.12 0.75

V16 % cover 35 1.0

26

Table 2. (Concluded)

Adult Embryo Juvenile

Variables Data SI Data SI Data SI

V17 Substrate cover 20 1.0

HSI = lowest SI S40re for 0.7 0.5 0.6the life stage or species

aThe data sets are from hypothetical measurements. The corresponding SI scoresare from the chinook salmon SI graphs.

bUse variable V7 for spring spawning chinook only.

cUse base and peak flow data for embryos only if the embryos and yolk sac fryare still in the gravel during 'base and peak flow periods. If base or peakflow occur after emergence, then use the minimum and maximum flows that occurduring the intergravel stage for variables V1 1 and V1 2 for the embryocomponent.

27

Habitat variables Life regui sites

Average maximum or minimum pH (V,)--

Maximum temperature (V2)--------~

Minimum DO (VJ)----------------~~------Adult----------

% poo1s (V.) ------------------

Pool class (Vs)----------------~

% fines (V,.)

Embryo--------~

J

imum tem-• or V,)

1 size (VB)

velocity (V.)

flow (V11)

flow V

Minimum DO (V )

Average peak

Average base

Average water

Maximum or minperature (V

Average grave

1-------HS I

Juvenile------~

H (V )mum or mlnlmum p , J-

erature (V2)

VJ)

Vs)

flow (V11)

flow (V'2)

ass (V'J)

es (V,.)

ogen (V, s)

Average peak

Nitrate-nitr

Average maxi

Maximum temp

Minimum DO (

% pools (V. )

Pool class (

Average base

Substrate cl

% riffle fin

% cover (V,.)--------------------

Substrate cover (V,,)-------------

Average velocity (V'B)-----------

Figure 1. Diagram illustrating the relationship among model variables,components, and HSI.

28

2. Embryo component. It is assumed that the variables average gravelsize (Va), average water column velocity (V9 ), and percent fines

(V lO ) are interacting compensatory variables (Va = 0.5, V9 = 1.0,and V1 0 = 0.9, Table 2).

Lowest SI = 0.5 + 1.~ + 0.9 = 0.8

The SI tor variable Va would increase from 0.5 to 0.8 and the embryo

component SI would now be gravel (Va) and base flow (V 1 1 ) limited.

The embryo component SI would increase from 0.5 to 0.8.

The species HSI would increase from 0.5 to 0.6 (V1 2 and V1 3 ) this

being the lowest remaining SI score for any model component.

Model users are encouraged to devise other models or to make model altera-tions based on their knowledge of chinook salmon ecology. Alterations to themodels, however, should be fully documented.

INSTREAM FLOW INCREMENTAL METHODOLOGY

The Instream Flow Incremental Methodology (IFIM) was designed to quantifychanges in the amount of habitat available to different species and lifestages of fish (or macroinvertebrates) under various flow regimes (Bovee 1982).The IFIM can be used: to help formulate instream flow recommendations, toassess the effects of altered streamflow regimes, on habitat improvementprojects, for mitigation proposals, for fish stocking programs, and to assistin negotiating releases from existing water storage projects. The IFIM has amodular design, and consists of several autonomous models that are combinedand linked as needed by the user. One component of the IFIM is the PhysicalHabitat Simulation System (PHABSIM) (Milhous et al. 1984). The output fromPHABSIM is a measure of physical microhabitat availability as a function ofdischarge and channel structure for each set of habitat suitability criteria(SI curves) entered into the model. The output can be used for several IFIMhabitat display and interpretation techniques, including:

1. Habitat Time Series. Determination of impact ofspecies' life stage habitat by imposing projectover baseline flow time series conditions anddifference between the corresponding time series;

a project on aoperat i on curvesintegrating the

2. Effective Habitat Time Series. Calculation of the habitat require-ments of each life stage of a single species at a given time byusing habitat ratios (relative spatial requirements of various lifestages); and

29

3. Optimization. Determination of flows (daily, weekly, and monthly)that minimize habitat reductions for a complex of species and lifestages of interest.

Suitability Index Curves as Used in IFIM

PHABSIM utilizes Suitability Index (SI) curves that describe the instreamsuitability of the habitat variables most closely related to stream hydraulicsand channel structure (e.g., velocity, depth, substrate, and cover) for eachmajor life stage of a given fish species (e.g., spawning, egg incubation,larval, juvenile, and adult). The National Ecology Center has designated fourcategories of curves and standardized the terminology pertaining to the curves(Armour et a1. 1984). Category one curves are based on 1iterature sourcesand/or professional opinion. Category two (utilization) curves, based onfrequency analyses of field data, are fit to frequency histograms. Categorythree (preference) curves are utilization curves with the environmental biasremoved. Category four (conditional preference) curves describe habitatrequirements as a function of interaction among variables. The designation ofa curve as belonging to a particular category does not imply that there aredifferences in the quality or accuracy of curves among the four categories.

Availability of SI Curves for Use in IFIM

The SI curves available for IFIM analyses of chinook salmon habitat arecategory one and two (Figures 2-19), based on combinations of judgement,information derived from the literature, and field data. Investigators areencouraged to revi ew the curves carefully and verify them before use in I FIManalyses. Any discrepancies in the curves reproduced here are a result ofmisinterpretation by the authors, and not attributable to the studies cited.

At the time of this writing, numerous investigators were collecting datafor chinook salmon SI curve development. Curve users may wish to contact theInstream Flow and Aquatic Systems Group to determine the latest in availablecriteria before undertaking an instream flow study.

30

Coordinates 1.0x x y >:

em ft 51 ClJ--- ] 0.8H

0.0 0.0 0.0 >,9.1 0.3 0.0 .~ 0.6

15.2 0.5 1.0 ~.,.,3048.0 100.0 1.0 ,D13 0.4,,.,

::JCf) 0.2

0.00 10 20 30

Depth (cm) at velocitiesless than 61 cm/s (2 ft/s)

x x y°C of 51 1.

>:0.0 32.0 0.0 ClJ"0 O.2.0 35.6 0.0 pH7.0 44.6 1.0 >,

13.0 55.4 1.0 +J.,.,16.0 60.8 0.0 ~.,.,30.0 86.0 0.0 ,Dctl O.+J,,.,

::JCf)

O.3

Temperature (OC)

Figure 2. Category one 51 curves for chinook salmon passage depth andtemperature suitability (from 5autner et al. 1984; Meyer et al. 1984).

31

Coordinates 1.0x x y

cmls ft/s SI0.8

0.0 0.00 0.00 l=:015.2 0.50 0.00 ''';+J 0.622.9 0.75 0.08 tilN38.1 1.25 0.24 ''';

~ 0.453.3 1. 75 0.60 +J83.8 2.75 1. 00 t>99.1 3.25 0.60 0.2

129.5 4.25 0.36144.8 4.75 0.24 0.0152.4 5.00 0.00 a 100 200

3048.0 100.00 0.00Velocity at 0.2 of depthfrom stream bottom (cm/s)

x x ycm ft S1 1.0

0.0 0.0 0.000.830.5 1.0 0.00 l=:

45.7 1.5 0.10 0''';

106.7 3.5 0.38 +J 0.6til137.2 4.5 0.81 N

''';

198.1 6.5 0.90 r-i 0.4228.6 7.5 1.00''';+J

289.6 9.5 0.38~

350.5 11. 5 0.10 0.2365.8 12.0 0.00

3048.0 100.0 0.00 0.0400

Depth

Figure 3. Category two SI curves for migrating chinook salmon spawners;velocity and depth utilization during migration holding (from Burgeretal.1982).

32

Coordinatesx L

o 0Vmin-.001 0

Vmin 1Vc 1

Vc+.001 0100 0

Vmin is the mlnlmum velocitynecessary to prevent siltationof spawning sites; Vc is thecritical velocity, above whichscouring of spawning sites willoccur.

x L

0 0Dmin-.001 0

Dmin 1100 1

Dmin is either the minimumdepth required for egg incuba-tion (~ 0.0) or ice depth (whenice is present during eggincubation).

1.0

~Q) 0.8'"0~

H

>-. 0.6~.,-lM',-l

0.4.oCd~.,-l;:l

0.2ir:

0.0 I

Vrnin Vc

Velocity

1.0

~Q) 0.8'"0~

H

>-. J.6-~

.,-lM.,-l

.g 0.4~

',-l;:l

ir: 0.2

0.0 IDmin

Depth

Figure 4. 51 curves for spawning/egg incubation velocity and depth,for effective spawning habitat analyses.

33

Coordinatesx x y

cm/s ft/s 51

0.0 0.0 0.012.2 0.4 0.045.7 1.5 1.073.2 2.4 1.0

131.1 4.3 0.03048.0 100.0 0.0

~

~ 0.8i=:

H

G 0.6.,..,..--i.,..,.g 0.4.j.J.,..,::l(/} 0.2

a.O'-f-~-----.---_..........-r-""-'--'I-a 50 100 150

Mean column velocity (cm/s)

1.0I

~0.8x x Y Q)'"Cl

cm ft 51 i=:H

0.0 0.0 0.0:>, 0.6-.j.J.,..,

15.2 0.5 0.0 ..--i.,..,0.4-30.5 1.0 1.0 ..0co

3048.0 100.0 1.0 .j.J'H::l 0.2(/}

0.0a 50 100 150

Depth (em)

1.

~ O.X X Y Q)inches 51

'"Clcm i=:H

0.0 0.00 0.0 :>,.j.J0.4 0.16 0.0 'H..--i2.0 0.79 1.0

.,..,

..0

11. 0 4.33 1.0 co.j.J13.0 5.12 0.7

.,..,::l

15.0 5.91 0.2(/}

17.0 6.69 0.0 o.100.0 39.37 0.0 a 5 10 15 20

Average substrate particlesize (em)

Figure 5. Category one 51 curves for chinook salmon spawning, eggincubation, and intergravel fry velocity, depth, substrate, percentfines, and temperature suitability.

34

Coordinatesx x y 1.0

Fines ~ 0.8 mm Fines> 0.8 mmor 0.03 inches or 0.03 inches

,:>: \

(solid 1i ne) (broken line) 51 (lI 0.8 \'""0~ \

H

0.0 0.0 1.0 \5.0 5.0 LO G 0.6 \.,., \7.0 11.0 0.9 M.,., \

10.0 21.0 0.6 ~ 0.4 \12.0 25.0 0.4 .IJ \.,.,20.0 35.0 0.0 ;::J 0.2 \en \100.0 100.0 0.0

\.

0.0 L100

Percent fines

1.0

:>:.gj 0.8~

H

G 0.6.,.,M.,.,~ 0.4.IJ.,.,a 0.2

,. •I ,I ,- I ,I ,I ,- I ,I

,I

,I

,I ,

- I,

I ,II :

,•0.0

o 10 20 30Temperature (OC)

x x YEgg incubation

Spawning and intergravel(solid line) fry (broken 1ine)

0C (0 F) °C (OF) S1

0.0 (32.0) 0.0 (32.0) 0.00.5 (32.9) - 0.0

- 3.0 (37.4) 0.04.4 (39.9) - 1.0

6.0 (42.8) 1.012.8 (55.0) 1.0

14.0 (57.2) 1.015.0 (59.0) 0.0

- 18.0 (64.4) 0.030.0 (86.0) 30.0 (86.0) 0.0

Figure 5. (concluded).

35

1.0

Coordinates ~ 0.8QJ'"0

x X Y ~cmls ft/s SI

H

p..., 0.6.I-J

0.0 0.0 0.25 'r-!n6.1 0.2 1. 00

'r-! 0.4..09.1 0.3 1. 00 Cll.I-J

18.3 0.6 0.50'r-!;:l 0.2

39.6 1.3 0.10CJ)

76.2 2.5 0.00 0.03048.0 100.0 0.00 a 50 100 150

Mean eolwnn velocity (em/s)

1.0

X X Y ~ft SI

QJ 0.8cm '"0~

H

0.0 0.0 0.0 p..., 0.63.0 0.1 0.0 .I-J'r-!

27.4 0.9 1.0 n'r-!0.461.0 2.0 1.0 ~

91.4 3.0 0.2 .I-J'r-!152.4 5.0 0.0 ;:l 0.2CJ)

3048.0 100.0 0.00.0

a 50 100 150Depth (em)

x X Y ~QJ°C of S1 '"0~

H

0.0 32.0 0.0 p...,.I-J2.0 35.6 0.0 'r-!n7.0 44.6 1.0 'r-!

14.0 57.2 1.0 ~.I-J16.0 60.8 0.0 -r-!;:l30.0 86.0 0.0 Vl

o.a 10 20 30

Temperature (OC)

Figure 6. Category one SI curves for chinook salmon fry velocity,depth, and temperature suitability.

36

Coordinates 1.0x x Y

~

cmls ft/s 51

Coordinates 1.0x x y

cmls ft/s 510.8

0.0 0.0 0.00 r:: 0.615.2 0.5 0.05 0'M27.4 0.9 0.90 +.JC'il33.5 1.1 1. 00 N'M 0.451.8 1.7 1.00 .-i'M61. a 2.0 0.55 +.J:=>91.4 3.0 0.00 0.2

3048.0 100.0 0.000.0

a 50 100 150Mean column velocity (cm/s)

1.

x x ycm ft 51 o.

r::0

0.0 0.0 0.0 'M+.J9.1 0.3 0.2 C'ilN

24.4 0.8 1.0 'M.-i36.6 1.2 1.0 'M+.J42.7 1.4 0.5 :=>61.0 2.0 0.1

3048.0 100. a 0.1o.

a 50 100 150Depth (em)

Figure 8. Category two 51 curves for spring chinook salmon spawningvelocity and depth utilization (n=252; from 5ams and Pearson 1963).

38

Coordinates 1.0x x y

cm/s ft/s 51 0.8

0.0 0.0 0.0r::0

0.6'M27.4 0.9 0.3 +-Itil45.7 1.5 1.0 N'M64.0 2.1 1.0 M 0.4'M76.2 2.5 0.3 +-Ip91.4 3.0 0.0 0.2

3048.0 100.0 0.0

0.00 50 100 150

Mean column velocity (cm/s)

1.x x y

cm ft 51o.

0.0 0.0 0.00 r::9.1 0.3 0.05

0O.'M

21.3 0.7 1.00+-Itil

33.5 1.1 1.00N'M

36.6 1.2 0.40 M'M45.7 1.5 0.10 +-Ip

3048.0 100.0 0.10

O.50 1 0 1 0

Depth (em)

Figure 9. Category two 51 curves for fall chinook salmon spawningvelocity and depth utilization (n=107; from 5ams and Pearson 1973).

39

Coordinates 1.0x x y

cm/s ft/s 51 0.8l=:

0.0 0.0 0.0 0',-i 0.621.3 0.7 0.0.jJ

co27.4 0.9 0.2 N',-i39.6 1.3 1.0

,..,0.4',-i

48.8 1.6 1.0.jJ

0

88.4 2.9 0.2 0.2137.2 4.5 0.0

3048.0 100.0 0.00.0

0 50 100 150

Velocity at 15.2 ern (0.5 f t )above stream bottom (em/s)

x x Y LOcm ft 51

0.80.0 0.0 0.0 l=:09.1 0.3 0.0 ',-i.jJ 0.618.3 0.6 0.2 coN

24.4 0.8 1.0 .",..,54.9 1.8 0.2 ." 0.4.jJ67.1 2.2 0.0 0

3048.0 100.0 0.0 0.2

0.00 50 100 150

Depth (ern)

Figure 10. Category two 51 curves for fall chinook salmon spawningvelocity and depth utilization (n=216; from Vogel 1982).

40

Coordinates 1.0x x y

cmls ft/s S1 0.8~

0.0 0.0 0.00.~

+J 0.615.2 0.5 0.0 (1jN33.5 1.1 0.1 .~57.9 1.0

r-l0.41.9 .~+J

85.3 2.8 1.0 :::J121. 9 4.0 0.0 0.2

3048.0 100.0 0.0

0.00 50 100 150

Mean column velocity (cm/s)

x x Y 1.0cm ft S1

0.0 0.0 0.0 c12.2 0.4 0.0 0'..-i27.4 0.9 1.0 +J 0.6(1j36.6 1.2 1.0 N.~61.0 2.0 0.1 r-l'..-i 0.491. 4 3.0 0.0 +J:::J

3048.0 100.0 0.00.2

0.00 50 100 150

Depth (em)

Figure 11. Category two S1 cur~es for spring chinook salmon spawningvelocity and depth utilization (n=118; from Stempel 1984).

41

Coordinates 1.0x x y

cmls ft/s SI 0.8

0.0 0.0 0.00l::0

·ri 0.69.1 0.3 0.00 ~C1l24.4 0.8 0.25 N51.8 1.7 1. 00

·ri 0.4.-f·ri

70.1 2.3 1. 00 ~79.2 2.6 0.60

;::J

0.2137.2 4.5 0.00

3048.0 100.0 0.000.0

a 50 100 150Mean column velocity (cm/s)

1.0x x y

cm ft SI ~ O. a-Cll-e0.0 0.0 0.0 l::H

0.6-15.2 0.5 0.0 :>-.30.5 1.0 1.0 ~·ri

121. 9 4.0 1.0 .-f·ri 0.4:3048.0 100.0 1.0 .cC1l

~

°ri 0.2-;:lCJ)

O.u I Ia 50 100 150

Depth (em)

Figure 12. SI curves for chinook salmon spawning velocity (categorytwo) and depth (category one) (n=265; from Vincent-Lang et al. 1984).

42

Coo rd ina te sx x Y l.0

cmls ft/s 51---

0.0 0.0 0.000.8

9.1 0.3 0.00 l:::027.4 0.9 0.04 .r-! 0.6.u51.8 1.7 0.26 coN76.2 2.5 1. 00 'r-! 0.4r-i82.3 2.7 0.86 'r-!.u

112.8 3.7 0.52 ~125.0 4.1 0.12 0.2

131.1 4.3 0.02149.4 4.9 0.02 0.0155.4 5.1 0.00 a 50 100 150

3048.0 100.0 0.00 Velocity at 15.2 em (0.5 f t )above stream bottom (em/s)

x X Y l.0cm ft 51

0.0 0.00 0.000.8

15.2 0.50 0.00 l:::022.9 0.75 0.09 'r-! 0.6.u53.3 1. 75 0.37 coN68.6 2.25 0.84 .r-! 0.4r-i99.1 3.25 1. 00 .r-!.u

114.3 3.75 0.53 ~160.0 5.25 0.05 0.2216.4 7.10 0.01219.5 7.20 0.00 0.0

3048.0 100.00 0.00 a 50 100 150Depth (em)

Figure 13. Category two 51 curves for chinook salmon spawningvelocity and depth utilization (n=436; from Kurko 1977).

43

Coordi nates 1.0x x y

cm/s ft/s 51 0.8---

0.0 0.0 0.00 c09.1 0.3 0.25 'M 0.6.w

12.2 0.4 1. 00 coN15.2 0.5 1. 00 'M 0.4r-f21. 3 0.7 0.50 'M.w39.6 1.3 0.10 ;::J91.4 3.0 0.00 0.2

3048.0 100.0 0.000.0

0 50 100 150

Mean colunm velocity (cm/s)

x x y l.0cm ft S1

0.0 0.0 0.000.8

c30.5 1.0 0.10 0'M48.8 1.6 0.25

.w 0.6co70.1 2.3 1.00 N'M82.3 2.7 1. 00 r-f'M 0.491. 4 3.0 0.40 .w;::J

121. 9 4.0 0.100.2152.4 5.0 0.00

3048.0 100.0 0.000.0

0 50 100 1 0

Depth (em)

Figure 14. Category two S1 curves for chinook salmon fry velocityand depth utilization (n=202; from Stempel 1984).

44

Coordinates 1.0

x x ycm/s ft/s 51 0.8---

~

0.0 0.00 0.40a

'M 0.61.5 0.05 0.95

+Jco

3.0 0.10 1. 00N

'M

9.1 0.30 0.60r-i 0.4'M

48.8 1. 60 0.03+J~

57.9 1. 90 0.03 0.261.0 2.00 0.00

3048.0 100.00 0.000.0

0 50 100 150

Mean column velocity (cm/s)n=948

x x Y 1.0cm inches 51

0.0 0.00 0.00 0.80.1 0.04 0.40 ~1.6 0.63 1. 00 a 0.6'M2.2 0.87 1. 00 +Jco3.0 1.18 0.20 N'M 0.410.0 3.94 0.30 r-i'M

12.0 4.72 0.05 +J~18.4 7.24 0,10 0.2

100.0 39.40 0.100.0

0 5 10 15 20

Substrate particle-size diameter (em)n=909

Figure 15, Category two 51 curves for chinook salmon fry velocityand substrate utilization (from Burger et al. 1982),

45

Coordinatesx x y 1.0

cm/s ft/s SI--- >::aJ 0.8

0.0 0.00 0.50 "0c::4.6 0.15 1. 00 H9.1 0.30 1.00 e-, 0.6-IJ

12.2 0.40 0.50 'r-!..-i30.5 1. 00 0.30 'r-! 0.4"§45.7 1. 50 0.18 -IJ61. 0 2.00 0.10 .r-!;l

0.2106.7 3.50 0.00 Cf.l3048.0 100.00 0.00

0.00 50 100 150

Mean column velocity (em/g)

x x Y 1.0cm inches S1>::

0.0 0.0 0.00 aJ 0.8"03.0 0.1 0.00 c::H

21.3 0.7 1. 00 :>--. 0.630.5 1.0 1.00 +J

'r-!36.6 1.2 0.75 ..-i',.-1 0.461.0 2.0 0.50 ..0til91. 4 3.0 0.15 +J

',.-1

121. 9 4.0 0.10 ;l 0.2Cf.l304.8 10.0 0.01762.0 25.0 0.01

3048.0 100.0 0.00 0.0 0 50 100 150

Depth (em)

Figure 16. Category one S1 curves for chinook salmon fry velocityand depth suitability (from U.S. Fish and Wildlife Service 1985).

46

Coordinatesy y

1.0x x S1 (clear; S1 (turbid;

cmls ft/s sol i d line1 broken line)---

0.80.0 0.00 0.18 0.42 J::1.5 0.05 1. 00 0'M 0.66.1 0.20 0.57 .l-Jell

10.7 0.35 1. 00 1. 00 N'M

15.2 0.50 0.80 r-l 0.4'M

19.8 0.65 1. 00 .l-J24.4 0.80 0.68 0.38

~

0.233.5 1.10 0.44 0.2542.7 1. 40 0.25 0.15

0.051.8 1. 70 0.18 0.0761.0 2.00 0.12 0.02 0 50 100 15070.1 2.30 0.06 0.01 Mean column velocity (em/s)79.2 2.60 0.00 0.00

3048.0 100.00 0.00 0.00

y yX x S1 (clear; S1 (turbid; 1.0

cm ft solid line) broken line)

0.0 0.00 0.00 0.00 0.83.0 0.10 1. 00 J::9.1 0.30 0.70 0'M 0.6.l-J

16.8 0.55 1. 00 ell24.4 0.80 0.85 0.75 N'M32.0 1. 05 1. 00 r-l 0.4·M47.2 1. 55 1. 00 0.55

.l-J~

54.9 1.80 0.50 0.262.5 2.05 0.30 0.5091.4 3.00 0.30 0.50 0.0

3048.0 100.00 0.30 0.50 0 50 100 150

Depth (em)

Figure 17. Category two S1 curves for chinook salmon juvenile velocity,depth, percent cover, and cover type utilization (from Suchanek et al.1984) .

47

http:1.--.1-.-.1

Coordi natesy y

x 51 (clear water; 51 (turbi d;solid l~_ brok.en line)

0 0.0 0.56SO 0.5

100 1.0 1. 00

0.8

0.6

0.4

0.2

a.Ol~""""'~~~---r----'-~~~"'--+-a 50 100

Percent areal cover

1.

X Cover type yCode description 51 o.

~0

1 Debris 0.90.....I-J

2 Undercut bank 1. 00coN

3 Rubble/cobble/boulder 0.20........-i

4 Aquatic vegetation 0.65.... o..I-J

5 Large gravel 0.25 t>

6 Overhanging veget?tion 0.38 o.7 -Emergent vegetation 0.308 No cover 0.01 O.

1 2 3 4 5 6 7 8

Cover type(in clear water)

Figure 17. (concluded).

48

Coordinates1.0

Y YMean column Nose

x x 51 n=947 51 n=163 0.8cmls ft/s ( sol id 1ine) (broken line) r::

0'M

0.60.0

+.J0.00 0.3 0.05 ('j

N1.5 0.05 0.7 'M3.0 0.10 0.20

.--i0.4'M

6.1 0.20 1. 00+.J~

7.6 0.25 0.8 0.212.2 0.40 1.0 1. 0015.2 0.50 1.018.3 0.60 0.7 0.024.4 0.80 0.50 0 50 100 15030.5 1. 00 0.5 Velocity (cm/s)33.5 1.10 0.1039.6 1. 30 0.242.7 1.40 0.0567.1 2.20 0.0070.1 2.30 0.0

3048.0 100.00 0.0 0.00

x x ycm inches 51 1.0

0.0 0.00 0.00 0.80.2 0.08 0.60 r::1.6 0.63 1. 00 0'M2.2 0.87 1. 00 +.J 0.6('j2.6 1. 02 0.20 N'M9.2 3.62 0.03 .--i'M 0.4

10.0 3.94 0.20 +.J~18.4 7.24 0.20

0.2

0.00 5 10 15 20

Substrate particle-size diameter (em)n=880

Figure 18. Category two 51 curves for chinook salmon juvenilevelocity and substrate utilization (from Burger et al. 1982).

49

Coordinates 1.0x x y

cm/s ft/s S1x 0.8Q)

0.0 0.00 0.30 '"004.6 0.15 0.55 H 0.69.1 0.30 0.90 :>,

~

12.2 0.40 1. 00 'Mr-l 0.424.4 0.80 1. 00 'M,.029.0 0.95 0.85 til

~

36.6 1. 20 0.30 'M 0.2::l53.3 1. 75 0.15 (/)

106.7 3.50 0.05 0.0137.2 4.50 0.01 0 50 100 150152.4 5.00 0.00

3048.0 100.00 0.00 Mean column velocity (em/s)

x x ycm ft S1 l.0

0.0 0.0 0.00 xQ) 0.86.1 0.2 0.00 '"0024.4 0.8 0.90 H30.5 1.0 1. 00 :>, 0.6

~

76.2 2.5 1.00 'Mr-l91.4 3.0 0.75 'M 0.4

121. 9 4.0 0.20 ~~

152.4 5.0 0.10 'M::l304.8 10.0 0.10 (/) 0.2762.0 25.0 0.01

3048.0 100.0 0.011 0

Depth (ern)

Figure 19. Category one S1 curves for chinook salmon juvenile velocityand depth suitability (from U.S. Fish and Wildlife Service 1985).

50

Spawning migration. The time period during which chinook salmon migrateupstream to spawn is dependent on locale, and the investigator will have todetermine the time period and the stream segments within which migrationhabitat is required. Little information was found in the literature concerningmigration habitat requirements of chinook salmon. We assume that the variablesthat may limit migration in most instances will include depth, velocity, andtemperature.

SI curves for adult chinook passage (Figure 2) are category one and weretaken from several sources. Sautner et al , (1984) selected chum salmon fordevelopment of passage criteria in the Susitna River, Alaska, because chumwere determined to be more susceptable to migration obstacles than were othersalmon species within the study area. Sautner et al. assumed that the lengthof a passage reach at limiting water depths was the most important variable intheir area. Since passage criteria were not found for chinook salmon, theauthors assume that criteria for chum salmon will satisfy chl nock migrationrequirements. Information on maximum water velocities that can be toleratedby migrating chinook adults was not found, and investigators will need todevelop their own criteria for use in areas where velocity may be a problem.The SI curve for relative suitability of migration temperatures is based onseveral studies (Meyer et al. 1984) and may require tailoring for specificspawning runs in areas of interest.

Burger et al. (1982) collected data to characterize migration holdingareas in the Kenai River, Alaska. Chinook salmon ranging in length from 74 to117 cm (29 to 46 inches) were radio-tagged and followed to spawning areas.Depths and velocities were measured at point locations of holding adults(n = 54). Velocities were measured at 0.2 of the total depth from the bottom,the point closest to where the individual fish were assumed to be located.The category two SI curves for migration holding (Figure 3) were developed byconnecting the midpoints of frequency histogram class intervals.

Spawning and egg incubation. The time period during which spawning andegg incubation habitat is required for chinook salmon is variable (dependingon locale), and should be determined bef