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Fisheries resource maintenance flows for Pacific salmon Hamilton, Roy Ernest 1978

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FISHERIES RESOURCE MAINTENANCE FLOWS FOR PACIFIC SALMON by ROY ERNEST HAMILTON A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF CIVIL ENGINEERING We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 1978 © Roy Ernes t Hamilton 1978 In presenting th i s thes is in pa r t i a l fu l f i lment o f the requirements f an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree tha the L ibrary sha l l make it f ree l y ava i l ab le for reference and study. I further agree that permission for extensive copying of th i s thesis for scho lar ly purposes may be granted by the Head of my Department or by his representat ives. It is understood that copying or pub l i ca t ion of th is thes is fo r f inanc ia l gain sha l l not be allowed without my writ ten permission. Department of CIVIL ENGINEERING The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 D a t e A p r i l 28. 1-978 i i ABSTRACT The s t a t u t o r y background of water use and the c o n f l i c t with instream uses i s reviewed. H a b i t a t c r i t e r i a f o r the s e v e r a l phases — m i g r a t i o n , spawning, i n c u b a t i o n , and r e a r i n g — of the f r e s h water l i f e c y c l e of salmon are pro v i d e d . Stream channel morphology and h y d r a u l i c s are d i s c u s s e d , r e l a t i v e to salmon h a b i -tat requirements and the de t e r m i n a t i o n of f i s h e r i e s resource maintenance flows. The r e l a t i o n s h i p Between watershed hydrology and the f r e s h water l i f e c y c l e of salmon i s d e s c r i b e d , and tech-niques, with, examples, are given f o r a n a l y s i n g low flows f o r gaged and ungaged watersheds. Some of the more recent methodologies f o r e s t a b l i s h i n g F i s h e r i e s Resource Maintenance Flows are reviewed and a new technique, using the u t i l i t y curve concept to combine q u a l -i t a t i v e and q u a n t i t a t i v e i n f o r m a t i o n , i s i n t r o d u c e d . The advan-tages of t h i s technique are that d e f i n i t e incremental values of p o t e n t i a l p r o d u c t i v i t y can be determined f o r a s e r i e s of flow l e v e l s , based on e i t h e r e m p i r i c a l data or expert o p i n i o n , or a combination of both, f o r subsequent resource e v a l u a t i o n and d e c i -s i o n making. A step by step procedure i s given f o r . e s t a b l i s h i n g F i s h e r i e s Resource Maintenance Flows, and some of the aspects of water management p e r t a i n i n g to r e c o g n i t i o n of instream flow r e q u i r em en ts- are ad dr as s. e d « i i i TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION 1 I I . STATUTORY BACKGROUND . . . . . . . . . . 5 I I I . HABITAT CRITERIA 11 Upstream M i g r a t i o n . 17 Spawning. . . . . . . . . 19 Incubation. , f . . . . . . . . 23 Rearing . . . . . . . . . . . . . 26 Cover 26 Food 28 General Rearing P r o d u c t i v i t y 30 Downstream M i g r a t i o n 31 IV. STREAM HYDRAULICS. 32 Spawning 3 2 Spawning and Subsurface Flow 39 C a l c u l a t i o n of P r e f e r r e d Spawning Areas . . . 42 Incubation 53 P o o l - R i f f l e Theory 54 H y d r a u l i c s of Rearing and Food P r o d u c t i o n . . . . 55 Upstream M i g r a t i o n . . . . . 56 V. STREAM MORPHOLOGY. . . . . . . . . . . . . . . .: . . 59 Incubation. I V TABLE OF CONTENTS cont'd CHAPTER VI. HYDROLOGY cont'd Rearing .. . . . . . . . Gaged Watersheds U n g a g e d W a t ex shed s VII. TECHNIQUES AND METHODOLOGIES . . . . Upstream M i g r a t i o n . . . . . . . . Spawning, . . . . , . . Incubation. . . . . . . . . . . . Rearing . . . . . . . . . . . . . Downstream M i g r a t i o n . . . . . . . V I I I . INCREMENTAL ANALYSIS . . . Rearing . . . . . . . . . . . . . Spawning Incubation. . Upstream and Downstream M i g r a t i o n LITERATURE CITED GLOSSARY . . . . APPENDIX A. . . APPENDIX B. . . APPENDIX C. . ..; PAGE 68 71 7 3 80 81 83 84 85 89 91 99 104 104 105 IX. PROCEDURE FOR ESTABLISHING FISHERIES RESOURCE MAINTENANCE FLOWS 1 0 6 X. WATER MANAGEMENT 1 1 0 113 117 118 133 137 V LIST OF TABLES TABLE A I. A l l A l l I AIV BI CI Program "Streamf low", sample, output f o r .a s e c t i o n at a s p e c i f i e d flow. Program "Streamflow", sample output f o r a summary t a b l e . Data cards f o r computer program."Streamflow" P a r t i a l l i s t of symbols used In computer programe "Streamflow". Spawning and r e a r i n g flows f o r salmon, d e r i v e d from b a s i n parameters. Basin parameters and 7 - day low flows f o r s e v e r a l r i v e r s on Vancouver I s l a n d . PAGE 123 124 125 126 136 141 v i LIST OF FIGURES FIGURE PAGE 1. Fresh Water L i f e C y cles of Campbell River Salmon . . 15 2. Fresh. Water L i f e Cycles; of Sooke River Salmon. . . . 16 3. Swimming Speeds of Salmon. . . . . . . . . . . . . . 18 4. Reported Spawning D e p t h / V e l o c i t y C r i t e r i a f o r Coho and. Sockeye Salmon . . . . . . . . 20 5. Reported Spawning D e p t h / V e l o c i t y C r i t e r i a f o r Pink and Chum Salmon. . . . . . . . . . . . . . 21 6. Reported Spawning D e p t h / V e l o c i t y C r i t e r i a f o r F a l l and Spring Chinook Salmon 22 7. R e l a t i o n s h i p of Nose V e l o c i t y to Average V e l o c i t y (Nechako River) 24 8. R e l a t i o n s h i p of Nose V e l o c i t y to Average V e l o c i t y (Capilano R i v e r , Brothers Creek and Sooke River) . . 25 9. Benthic P r o d u c t i o n 29 10. A Simple Substrate Sampler 34 11. Layout of a T y p i c a l Study S i t e . 35 12. Thalweg P r o f i l e of Study S i t e 2 (Sooke R i v e r ) . . . . 37 13. I n t r a g r a v e l Flow at a Redd and at a P o o l - r i f f l e . . . 40 14. I n t r a g r a v e l Flow at a Boulder and near a More Permeable Lens 41 15. Spawning H a b i t a t Related to Flow (Sooke River) . . . 43 16. Depth and V e l o c i t y P r o f i l e s f o r Transects 1 to 4 at 150 c . f . s 44 17. Depth, and V e l o c i t y P r o f i l e s f o r Transects 5 to 8 at 65 c . f . s . . . . . . . ... . . . . . . . . . ... . . . 45 18. Depth and V e l o c i t y P r o f i l e s f o r Transects 5 to 8 at 550 c. f . sv .] . .' •! . . . . . . . . . . . . . . . . 46 19_. R e l a t i o n s h i p Between Energy Slope and discharge f o r Oak Creek, Oregon ([after Milhous) . . . . . . . . . . 49 v i i LIST OF FIGURES cont'd FIGURE PAGE 20. R e l a t i o n s h i p Between Manning's "n" and Discharge f o r Oak Creek, Oregon ( a f t e r Milho us) • • • • 50 21. R e l a t i o n s h i p Between C and Discharge f o r Oak Creek, Oregon ( a f t e r Milhous) . 51 22. Stage-discharge Curve f o r Oak Creek, Oregon ( a f t e r Milhous).. 52 23. R e l a t i o n s h i p Between Wetted Width and Discharge . . 60 24. V a r i a t i o n s i n Flow Along Deadman R i v e r . 62 25. T y p i c a l Hydro graph, f o r Sooke River and L i f e Cycle Timing of Salmon. . . . . . . . . . . . . . 65 26. V a r i a t i o n s i n Flow Along the Salmon River . . . . . 75 27. I s o h y e t a l Map of Vancouver I s l a n d 77 28. D e f i n i t i o n Diagram of a Stream Segment and Sample E l e c t i v i t y Curves 94 29. U t i l i t y Curves f o r A n a l y s i s of Rearing H a b i t a t . . . 100 30. Procedure O u t l i n e f o r E s t a b l i s h i n g F i s h e r i e s Resource Maintenance Flows 107 A l "Streamflow" Computer Program Flow Chart 127 A2 "Pram" Subroutine Flow Chart.. 131 CI 7-day Low Flow Recurrence I n t e r v a l Curves f o r the Benson R i v e r and Kokish River 142 C2 R e l a t i o n s h i p s of the 7-day Low Flow to the Water-shed Parameter X-• • • • • • • • ' • • •• • • • v i i i ACKNOWLEDGEMENTS I; would l i k e to thank B i l l F i e l d , who prepared many of the drawnings and diagrams f o r t h i s t h e s i s . I a l s o took advantage of h i s m e t e o r o l o g i c a l e x p e r t i s e i n having him prepare an i s o h y e t a l map of Vancouver I s l a n d . C. C. C&ud)_ Graham gave me much, u s e f u l advice and c r i t i c i s m on the. b i o l o g i c a l content. The p a t i e n c e and s k i l l of Mary Fedosenko i n typing the manuscript has been much a p p r e c i a t e d . 1 CHAPTER I. INTRODUCTION The need to e s t a b l i s h flow requirements i n r i v e r s and streams f o r the fresh, water l i f e of salmon continues to grow as the p o p u l a t i o n of man, and h i s e x p l o i t a t i o n of n a t u r a l r e -sources, i n c r e a s e s . The l i m i t a t i o n of the water resource and the need for instream uses are becoming more widely r e c o g n i z e d . In 1976 the Instream Flow S e r v i c e Group, based at F o r t C o l l i n s , Colorado, was set up to c o o r d i n a t e Instream flow r e s e a r c h . There has a l s o been an i n c r e a s e i n r e s e a r c h a c t i v i t i e s i n r e -cent years by resource agencies and u n i v e r s i t i e s i n the Western American S t a t e s . The U n i v e r s i t y of Washington at Pullman i s d i r e c t i n g c o n s i d e r a b l e e f f o r t i n t h i s d i r e c t i o n . In B r i t i s h Columbia there i s a growing c o n f l i c t not only between the v a r i -ous water users, but a l s o between the water users and the F e d e r a l and P r o v i n c i a l f i s h and w i l d l i f e agencies, r e c r e a t i o n i s t s , and c o n s e r v a t i o n i s t s who want water reserved f o r instream uses. A question that i s a r i s i n g more f r e q u e n t l y i s : "What i s the eco-nomic worth of instream uses and can t h i s be expressed i n the usual economic terms f a m i l i a r to business and i n d u s t r y ? " . There i s no p r o v i s i o n i n the P r o v i n c i a l Water Act f o r instream flows. In the past, water l i c e n s e s have been i s s u e d u n t i l the stream, i n some cases, has been over recorded. That Is, more l i c e n s e s have been Issued than can be s a t i s f i e d by the stream - If the f u l l claims of a l l the l i c e n s e e s were to be 2 e x e r c i s e d . In more recent years the Water Comptroller has taken some cognizance of instream flow needs, but the Water Act r e -mains unchanged. In t h i s t h e s i s I. intend to provide an overview of the instream flow problem; but, because of i t s complexity and i n t e r d i s c i p l i n a r y nature, i t Is not p o s s i b l e to cover a l l aspects i n d e t a i l . The only aspects of water q u a l i t y that w i l l be con-s i d e r e d are those that are r e g u l a r l y i n c l u d e d i n salmon h a b i t a t a n a l y s i s - temperature, t u r b i d i t y and oxygen content. I t i s r e -cognized that p o l l u t i o n problems are i n t e n s i f i e d by low flow c o n d i t i o n s , and there are a number of common sources of p o l l u t i o n which I f not c o n t r o l l e d w i l l a f f e c t f i s h l i f e i n the stream. I. am not p r o v i d i n g a s e c t i o n on economics, although the c a l c u l a t i o n of f i s h e r y values are necessary and have been undertaken f o r some f i s h e r y s t u d i e s ( M i l l e r , 1976). To j u s t i f y the e f f o r t i n e s t a b l i s h i n g resource maintenance flows, i t may be s u f f i c i e n t to p o i n t out that the salmon f i s h e r y i s a renewable resource, p r o v i d i n g i t i s not overharvested and p r o v i d i n g the salmon streams are p r o t e c t e d and s u f f i c i e n t flows are maintained. The study of instream flow needs f o r f i s h i s d i f f i - ! . cultuhecause of the b i o l o g i c a l u n c e r t a i n t i e s of f i s h behaviour and the p h y s c i a l u n c e r t a i n t i e s a s s o c i a t e d with the s c i e n c e s of hydrology, stream h y d r a u l i c s , and channel morphology. I b e l i e v e that instream flow problems should be solved by using both quan-t i t a t i v e and q u a l i t a t i v e techniques. The b i o l o g i s t s experience 3 or knowledge, which cannot always be r e a d i l y q u a n t i f i e d , and f i r s t hand l o c a l knowledge, can be i n c l u d e d i n the analyses by the use of the u t i l i t y curve technique (Chapter V I I I ) , Every r i v e r system i s unique, and every f i s h e r i e s r e l a t e d flow problem i s d i f f e r e n t to some degree. The whole watershed must be understood so that the best approach to the problem can be found. C e r t a i n techniques w i l l be more a p p r o p r i -ate than others f o r the type of watershed or the type of problem under study. Each watershed study becomes a case study. Some techniques or analyses w i l l be common, but no. one methodology i s l i k e l y to be u n i v e r s a l l y a p p l i c a b l e . I have concentrated on the engineering aspects of instream flow requirements f o r f i s h , but the s e p a r a t i o n of the engineering from the b i o l o g i c a l i s not c l e a r . For example, the measurement and a n a l y s i s of v e l o c i t i e s and depths of water i n a stream i s considered to be part of the en g i n e e r i n g s c i e n c e of h y d r a u l i c s ; yet, b i o l o g i s t s c o n s i d e r v e l o c i t i e s and depths to be b i o l o g i c a l parameters. In the f o l l o w i n g chapters, I w i l l d e s c r i b e the devel-opment and p r o v i s i o n s of the Water Act and the F i s h e r i e s A c t, to provide a backdrop a g a i n s t which the approach to instream flows w i l l be more c l e a r l y understood. Next, the l i f e needs and h a b i -t a t requirement of salmon, w i l l be. d i s c u s s e d . Then, the engineer-ing t o p i c s of H y d r a u l i c s , Stream Morphology, and Hydrology w i l l be covered. This w i l l lead Into a d i s c u s s i o n of. Techniques and 4 Methodologies. In Chapter V I I I , some of the e x i s t i n g methods f o r r a t i n g the e f f e c t s of changes i n flow l e v e l s , and the l i m i t -a t i o n s of these methods, w i l l be d i s c u s s e d ; and the use of the " u t i l i t y curve" (which combines q u a n t i t a t i v e and q u a l i t a t i v e knowledge) f o r s o l v i n g problems i n incremental a n a l y s i s w i l l be developed. The general Procedure f o r Establishment of F i s h e r i e s Resource Maintenance Flows w i l l be given i n Chapter IX and, l a s t l y , some ideas on water resource, management p e r t a i n i n g to Instream flows w i l l be presented. 5 CHAPTER II STATUTORY BACKGROUND To understand c e r t a i n d i f f i c u l t i e s a s s o c i a t e d with the establishment of F i s h e r i e s Resource Maintenance Flows i t i s u s e f u l to review, B r i e f l y , the development of water law. When Eastern United States and Eas t e r n Canada were s e t t l e d , the R i p a r i a n D o c t r i n e of water law, as used i n England, was adopted. Under t h i s d o c t r i n e , ownership of land adjacent to the stream ( r i p a r i a n land) i s an absolute p r e r e q u i s i t e to the r i g h t to have access to and use the water. This i s why e a r l y farms i n Ea s t e r n Canada were surveyed i n long narrow ribbons each with a small frontage on the r i v e r or stream (Redel, 1967). Each r i p a r i a n owner on a given stream has equal r i g h t to the water whether or not he i s a c t u a l l y . u s i n g i t . R i p a r i a n law was o r i g i -n a l l y developed to p r o t e c t m i l l operators who used the water i n the stream to turn water wheels. As i t was a nonconsumptive use of water, each r i p a r i a n owner could have an equal r i g h t to i t s use without c o n f l i c t . When s i g n i f i c a n t q u a n t i t i e s of water are d i v e r t e d t h i s d o c t r i n e i s d i f f i c u l t to maintain. The r i g h t s of r i p a r i a n owners extend to the "middle thread" of the r i v e r . They own the submerged bed of the r i v e r to the middle thread, and hold both water r i g h t s and f i s h i n g r i g h t s o v e r - the submerged l a n d . 6 I t i s i n t e r e s t i n g to note that the o l d r i p a r i a n d o c t r i n e , being p r o t e c t i v e of the r i g h t of n a t u r a l flow "without di m i n u t i o n i n q u a l i t y and q u a n t i t y " , i m p l i c i t l y provides p r o t e c -t i o n of the f i s h e r y by m a i n t a i n i n g instream flows of uncontam-inated water. When the Western United States and Western Canada were s e t t l e d , a new water law was necessary. Major water users were miners and, l a t e r , I r r i g a t o r s who needed to d i v e r t l a r g e amounts of water some d i s t a n c e away from the stream. . The law that was developed i s c a l l e d the A p p r o p r i a t i o n D o c t r i n e , which e s t a b l i s h e d that " F i r s t i n time i s f i r s t i n r i g h t " . The f i r s t person who a p p l i e s f o r a water r i g h t on a stream has f i r s t p r i -o r i t y . F o l l o w i n g a p p l i c a n t s have dec r e a s i n g p r i o r i t y a c c ording to date of t h e i r a p p l i c a t i o n s . The second main p r i n c i p l e of the a p p r o p r i a t i o n d o c t r i n e is: that of " b e n e f i c i a l use", which meant that a l i c e n s e e had to use water b e n e f i c i a l l y more or l e s s con-t i n u o u s l y . His l i c e n c e could be c a n c e l l e d i f the water was not d i v e r t e d and used ( a f t e r a set p e r i o d , u s u a l l y 3 y e a r s ) , or i f the water was not b e n e f i c i a l l y used. The l i c e n c e could be r e -duced i f not a l l the water was b e n e f i c i a l l y used. P r i o r to 1859. some r e c o g n i t i o n was given to r i p a r i a n r i g h t s i n B r i t i s h Columbia. At that time, mining was a booming i n d u s t r y and r e q u i r e d water f o r p l a c e r mining o p e r a t i o n s . There was a l s o a major need f o r i r r i g a t i o n water i n the dry i n t e r i o r . F o l l o w i n g the lead i n the Western United S t a t e s , the, a p p r o p r i a t i o n 7 d o c t r i n e was soon adopted. The f i r s t l e g i s l a t i o n towards a p r i o r a p p r o p r i a t i o n system i s contained i n the Gold F i e l d s Act of 1959 (De Beck 19.67). A f u r t h e r step was taken i n the Land Ordinance of 1865, and i n 1892 the Water P r i v i l e g e Act wiped out a l l remnants of r i p a r i a n r i g h t s , as f a r as water use was concerned. The B r i t i s h Columbia Water Act has not been appre-c i a b l y changed since 19.39^ , although i n 1960. a p r o v i s i o n was added to i n c l u d e the p r i n c i p l e of l i c e n s i n g ground water. This pro-v i s i o n has not yet been implemented. I t i s l e g a l l y p o s s i b l y , at the present time, to d i g a w e l l adjacent to a stream and e x t r a c t water that would l i k e l y a f f e c t the stream flow, and not r e q u i r e a l i c e n c e . The present Water Act does not recog n i z e instream use of water f o r the n a t u r a l f i s h e r y , f o r boa t i n g , or f o r other r e c r e a t i o n a l a c t i v i t i e s . The B r i t i s h North America Act of 1867 gave the Fed-e r a l government f u l l j u r i s d i c t i o n over both t i d a l and n o n - t i d a l f i s h e r i e s . For convenience, the a d m i n i s t r a t i o n of the f i s h e r i e s was s p l i t between the F e d e r a l and P r o v i n c i a l governments. The Fe d e r a l government r e t a i n e d a d m i n i s t r a t i v e c o n t r o l over the salm-on species and other t i d a l - w a t e r f i s h e s . The f r e s h water spe-c i e s , and some of the anadromous species (game f i s h such as steelhead and t r o u t ) , came under th.e j u r i s d i c t i o n of the Province.,, p a r t l y because of the p r o p r i e t o r y r i g h t s which, the Province had i n the land and the fresh, waters f l o w i n g over the lands. 8 The B.N.A. Act considered water to be " p r o p e r t y " and always owned by the Crown i n the r i g h t of the Province (because the u n a l i e n a t e d land of th.e province over which the water flows i s the p r o p e r t y of the Crown i n the r i g h t of the P r o v i n c e ) . The Act, then, e s t a b l i s h e d that the c o n t r o l of the use of water r e -sided with the P r o v i n c e . Even F e d e r a l water resource p r o j e c t s r e q u i r e P r o v i n c i a l water l i c e n s e s . I t was e s t a b l i s h e d by an appeal d e c i s i o n i n 1898 that the F e d e r a l government, i n l e g i s l a t i n g f o r f i s h e r i e s , could a f -f e c t p roperty (land and water) r i g h t s as f a r as i t might be necessary f o r the r e g u l a t i o n of the f i s h e r i e s . I t would appear, then, that the F e d e r a l F i s h e r i e s Act has precedence over the P r o v i n c i a l Water Act. This has never been s e r i o u s l y contested to date, as c o - o p e r a t i v e s o l u t i o n s have been a v a i l a b l e , but a great d e a l of d i s p u t e has occurred over s i m i l a r j u r i s d i c t i o n a l problems over f i s h e r i e s and other instream uses of water i n the United S t a t e s . S e c t i o n 20 (10) of the F i s h e r i e s A ct, which a p p l i e s to flows which must be l e f t i n the stream to maintain the f i s h -ery, Is the s e c t i o n of major i n t e r e s t to the t o p i c of F i s h e r i e s Resource Maintenance Flows. C l e a r l y , s e c t i o n 20 (10) c o n f l i c t s with t.h.e Water Act which i m p l i c i t l y allows t o t a l water d i v e r s i o n from a stream. In some.cases, l i c e n s e d d i v e r s i o n s on a stream a c t u a l l y t o t a l more than the n a t u r a l low flow. 9 There i s at present no c r i t e r i a which the Water Comptroller can use to judge the number of l i c e n s e s a given stream can support. A r u l e of thumb that has been used i s : i f the stream goes dry once i n 5 years due to water d i v e r s i o n s no more l i c e n s e s should be. i s s u e d , and the stream should be d e c l a r e d f u l l y recorded. Although t h i s may be a s a t i s f a c t o r y s o l u t i o n f o r a d m i n i s t r a t i o n of the Water Act, i t i s c l e a r l y untenable from a f i s h e r i e s standpoint. F o r t u n a t e l y , the Comptroller has wide d i s c r e t i o n a r y power, and so, to some extent, he can consider instream use of water when making d e c i s i o n s on water use c o n f l i c t s . At the pre-sent time, i n B r i t i s h Columbia, a l l l i c e n c e a p p l i c a t i o n s are r e f e r r e d to F e d e r a l and P r o v i n c i a l F i s h e r i e s Agencies. The Comp-t r o l l e r w i l l o f t e n agree to p l a c e r e s t r i c t i v e c l a u s e s i n l i c e n s e s , or even decide not to i s s u e a l i c e n c e , i f he c o n s i d e r s i t not to be i n the best p u b l i c i n t e r e s t . Most water l i c e n s e s are i s s u e d i n p e r p e t u i t y ( s u b j e c t to c a n c e l l a t i o n f o r non-use or non compliance with r e g u l a t i o n s of the Act) with r i g h t s to s e l l and t r a n s f e r . Even though, i n theory, a l l the water remains the permanent property of the Crown, t h i s l i c e n s i n g p r a c t i c e tends to t r a n s f e r a c o n s i d e r a b l e amount of water c o n t r o l to major l i c e n s e e s . For the f u t u r e , i f the Crown i s to r e t a i n c o n t r o l of the water and provide f o r f u t u r e instream environmental uses, l i c e n s e s should be i s s u e d on a term b a s t s . As "continued b e n e f i c i a l use" i s one of the primary 10 p r i n c i p l e s of water law i t i s p o s s i b l e f o r the Crown to r e t r i e v e c o n t r o l over some of the l i c e n s e d water (and re s e r v e I t f o r i n -stream use) by reviewing e x i s t i n g l i c e n s e s and c a n c e l l i n g or r e -ducing them to the q u a n t i t i e s t r u l y b e n e f i c i a l l y used. I t appears that the d e c i s i o n on j u s t how much water should be l e f t i n a stream i s u l t i m a t e l y going to hinge on the p r i n c i p l e of "most b e n e f i c i a l use". This w i l l come down to a socio-economic e v a l u a t i o n of a l l water uses, with the f u t u r e being considered. In order to evaluate instream flow needs f o r f i s h e r i e s i t i s necessary to have some t e c h n i c a l procedure f o r e s t a b l i s h i n g the importance of v a r i o u s l e v e l s of instream flow. This comes back to the idea of incremental a n a l y s i s which w i l l be developed i n Chapter V I I I . 11 CHAPTER I I I HABITAT CRITERIA The n a t u r a l stream h a b i t a t supporting f i s h l i f e can be evaluated by measuring a number of parameters found to be important to f i s h l i f e . Some of the parameters are: 1. R e l a t i n g to the channel: sub s t r a te bank, coyer instream cover veg eta t i o n morphology o r i e n t a t i o n shade 2. R e l a t i n g to the water: v e l o c i t y depth chemistry t u r b i d i t y temperature q u a l i t y ([pollution) 3. R e l a t i n g to l i f e : t e r r e s t r i a l i n s e c t s benthie i n v e r t e b r a t e s a q u a t i c i n s e c t s space ( t e r r i t o r l a 111 y ). 12 The v a l u e , or i n f l u e n c e , of the parameters v a r i e s c o n s i d e r a b l y . For example, there i s a d i r e c t p o s i t i v e r e l a t i o n -ship between the amount of h a b i t a t and the q u a n t i t y of water i n the stream. On the other hand, the value of t u r b i d i t y may be p o s i t i v e i f i t provides cover, or i t may be negative i f i t pre-vents p e n e t r a t i o n of l i g h t . Some parameters, such as q u a n t i t y , v e l o c i t y , and depth of water, are r e l a t i v e l y easy to measure. Depth of water i s perhaps the e a s i e s t ; i t v a r i e s with time of course, But a r e c o r d i n g gage overcomes t h i s problem s a t i s f a c t o i r r i l y . Quantity of f l o w i n g water can be measured a c c u r a t e l y enough f o r our purposes u s i n g normal hydrometrlc surveys. V e l o c -i t y i s d i f f e r e n t . Average v e l o c i t y i n a cross s e c t i o n , as d e t e r -mined by a number of c a r e f u l meterings, i s a f a i r l y r e l i a b l e q u a n t i t y . But the v e l o c i t y a f i s h p r e f e r s i n i t s immediate neigh-bourhood i s not so easy to determine. I t i s dependent on species and f o r k l e n g t h . A l s o , the v e l o c i t y at a p a r t i c u l a r p o i n t i n the stream 0.4 f e e t from the bottom (average nose p o s i t i o n of spawning salmon) w i l l vary i n magnitude and d i r e c t i o n with time. What i s the accuracy of t h i s measurement i f the g r a v e l s i z e s are 0.2 f e e t , or more, i n diameter (as they u s u a l l y are i n prac-t i c e ) ? What about the d i r e c t i o n of flow? I t may not be at r i g h t angles to the t r a n s e c t , and some meters do not e a s i l y d i s t i n g u i s h d i r e c t i o n . What i s the v e l o c i t y a few inches away from the mea-sured point? U s u a l l y , depth and v e l o c i t y measurements are not taken c l o s e r than 2 f e e t apart along.a t r a n s e c t and t r a n s e c t s are u s u a l l y 20 f e e t , or more, ap a r t . Measurement of v e l o c i t i e s 13 i n pools becomes very d i f f i c u l t as low v e l o c i t i e s tax the accu-racy of instruments. These l i m i t a t i o n s are not always r e c o g n i z e d . They can be overcome i n part by having crews experienced i n sur-veying and r i v e r h y d r a u l i c s do the f i e l d work. They can al s o be overcome, to some extent, i n a s t a t i s t i c a l sense, by ta k i n g many measurements of moderate p r e c i s i o n r a t h e r than a few measurements of high p r e c i s i o n . I t i s not u s u a l , In low flow work, to have to consid e r many water q u a l i t y parameters; t u r b i d i t y (from s i l t a t l o n ) , temper-ature, and d i s s o l v e d oxygen are the most common. Some of the water q u a l i t y problems that can be aggravated by low flows are: seepage from s e p t i c tanks or lagoons; l e e c h i n g from l o g g i n g d e b r i s , urban r u n o f f , and f e r t i l i z e d f i e l d s ; and the presence of l i v e s t o c k i n streams. I make the assumption t h a t . i f the h a b i t a t parameters of depth, v e l o c i t y , temperature, oxygen content, e t c . , are w i t h i n the ranges p r e f e r r e d by the f i s h , they w i l l choose t h i s h a b i t a t over other l e s s d e s i r a b l e h a b i t a t s . Of course, i t may w e l l be that, even i f the h a b i t a t i s i d e a l a c c ording to a l l the parameters we have decided to measure, i t w i l l be avoided because of some other l e s s obvious parameter that has not been measured. But i f the measurements are made, i n areas known to' be frequented by f i s h and are confirmed by observers t r a i n e d i n f i s h behaviour, much greater r e l i a n c e can be placed on such an assumption. 14 H a b i t a t requirements vary according to the time of year and phase of the salmon's l i f e c y c l e . There are a l s o v a r i -a t i o n s between the f i v e s p e c i e s of P a c i f i c Salmon: coho, chinook, pink, chum, and sockeye. The fresh, water phases of the l i f e c y c l e a re: 1. Upstream m i g r a t i o n 2. Spawning 3 . I n cubation 4. Rearing 5. Downstream m i g r a t i o n T y p i c a l l i f e c y c l e timing i s shown i n F i g u r e s 1 and 2. Chum-, pink and sockeye salmon, do not remain i n the spawning stream to r e a r . Chum and pink go out to sea as soon as they emerge from the g r a v e l at the end of the "incubation p e r i o d . Sock-eye move out of the stream a f t e r i n c u b a t i o n to rear i n a l a k e . Coho w i l l stay to rear i n the stream f o r one or, sometimes, two years. Chinook may move out to sea a f t e r about 90 days of r e a r -ing or they may stay i n the stream f o r a year. The other phases (.that i s , a l l except r e a r i n g ) of the f r e s h water l i f e c y c l e are common to a l l s p e c i e s . There are p e c u l i a r i t i e s of each s p e c i e s . Chum and pink salmon g e n e r a l l y spawn i n the lower reaches of streams c l o s e to t i d e water. Coho tend to d i s t r i b u t e w i d e l y i n a. system, endeavoring, i t seems, to go as f a r as p o s s i b l e up the t r i b u t a r i e s . They w i l l o f t e n spawn i n streams or d i t c h e s 2 or 3 f e e t i n width. There are many other CHINOOK COHO CHUM PINK / y!?RATIOlS / ^ A W N I N G / INCUBAT ION / R E A R I N G ^ G R A T I O N / / M IGRAT ION / { S P A W N I N G ) / ( I N C U B A T I O N ) / f , R E A R I MP » t- Y E A R L I N G S M O L T Ml GRAT ION / S P A W N I N G / I N C U B A T I O N / F R Y M IGRAT ION / ^mQBAl\OH^ SPAWN ING ^ I N C U B A T I O N ^ F R Y M IGRAT ION ^ AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL Ol FIGURE I FRESH WATER LIFE CYCLES OF CAMPBELL RIVER SALMON FIGURE 2 FRESHWATER LIFE CYCLES FOR SOOKE RIVER SALMON CHINOOK COHO z UPSTREAM MIGRATION and SPAWNING z INCUBATION z REARING and DOWNSTREAM MIGRATION z UPSTREAM MIGRATION and SPAWNING Z INCUBATION 7 L REARING YEARLING SMOLT MIGRATION CHUM Z UPSTREAM MIGRATION and SPAWNING z INCUBATION z DOWNSTREAM MIGRATION z SEP OCT NOV DEC JAN FEB MAR | APR | MAY | JUN | JUL | AUG Y E A R R O U N D R E S I D E N C E 17 v a r i a t i o n s between the s p e c i e s , and even w i t h i n the s p e c i e s , de-pending on the age and s i z e of the f i s h . In the f o l l o w i n g pages, each phase of the l i f e c y c l e w i l l be d e s c r i b e d i n more d e t a i l , with emphasis being placed on the e f f e c t s of flow. UPSTREAM MIGRATION A continuous water c o r r i d o r of s u f f i c i e n t width and depth, and a few deep r e s t i n g pools, are r e q u i r e d f o r the up-stream run. The swimming a b i l i t i e s of the species ([Figure 3) and the n a t u r a l slope of the r i v e r governs the upstream l i m i t s of the m i g r a t i o n . Problems a r i s e at s p e c i f i c l o c a t i o n s . Shallow reaches may be l i m i t i n g i f the water i s l e s s than about 0.5 f e e t deep and/or i f the water v e l o c i t y i s beyond the species (or f i s h s i z e ) c a p a b i l i t y . Some, or many, of the f i s h may be t i r e d or i n j u r e d so passage should be made as easy f o r them as p o s s i b l e . F a l l s and other instream o b s t r u c t i o n s are o f t e n the l i m i t i n g f a c t o r s . They may be passable at some flows and not others, depending oh t h e i r morphological f e a t u r e s and a s s o c i a t e d h y d r a u l i c c h a r a c t e r i s t i c s . The a b i l i t y to n e g o t i a t e past ob-s t r u c t i o n s depends on the s p e c i e s , t h e i r s i z e and t h e i r p h y s i c a l c o n d i t i o n . Coh.o may r e a d i l y jump 6 f e e t but pink and chum salmon have, d i f f i c u l t y jumping 2 or 3 f e e t . A d e t a i l e d review on the. s u b j e c t of upstream migra-t i o n has been prepared by Banks (19-69). 18 FIGURE 3 SWIMMING SPEEDS OF SALMON (AVERAGE SIZED ADULTS) SOCKEYE COHO CHINOOK 8 12 16 20 24 28 32 36 VELOCITY IN FEET/SECOND LEGEND III CRUISING SPEED SUSTAINED SPEED DARTING SPEED Adapted from Milo C. Bell (1973) 19 SPAWNING Salmon migrate up r i v e r by t h e i r o l f a c t o r y sense to the spawning ground where they o r i g i n a t e d . I f they cannot reach t h e i r d e s i r e d d e s t i n a t i o n because of an o b s t r u c t i o n , or because the o r i g i n a l spawning area has s h i f t e d or been destroyed, they w i l l g e n e r a l l y spawn i n another, nearby, area. Redds (nests) are dug i n stages over a p e r i o d of s e v e r a l days. Eggs are deposited i n the bottom of a d e p r e s s i o n made by the female, and a f t e r f e r -t i l i z a t i o n , are covered by g r a v e l from subsequent upstream d i g -ging. A p r o f i l e of a t y p i c a l redd i s shown i n F i g u r e 13. As f a r as i s known, ..:the primary spawning h a b i t a t pa-rameters are: depth, v e l o c i t y , temperature, oxygen content, s u b s t r a t e s i z e and composition, and the nature of the s u r f a c e — subsurface water interchange. F i g u r e s 4 to 6 summarize the depth and v e l o c i t y c r i t e r i a recorded i n the l i t e r a t u r e . Some of the curves are unbounded on the maximum depth side because the i n v e s -t i g a t o r s found that some spawning took place i n deeper water than would normally be expected. Deep water spawning of sockeye salmon has been observed on the F r a s e r River i n B r i t i s h Columbia. I t i s now general p r a c t i c e to measure or c a l c u l a t e the v e l o c i t y at the nose, p o s i t i o n of the spawning f i s h , which f o r salmon i s taken to be Q.4 f e e t above the streambed. As some i n v e s t i g a t o r s have used the average v e l o c i t y i n the water column, I have had to a d j u s t t h e i r v e l o c i t y l i m i t s s l i g h t l y to i n c o r p o -r a t e t h e i r data i n t o F i g u r e s 4 to 6, which are based on nose S o t m innniiin7rzri^riTCw;aircvnTfiira^ • • • • • • • • •i u • u • • • • • •1 •• m • • • • • • • • • • • m • • • • • • • • • • • • • • • m • • • • m i i 4 t i. \ I i T T 10 y I J • y )• R P" 7 T i n c ,i 1 c c ) f > 1 \\ )Pi Ir b J *i f 7 r C - * b J-5 )• -.f A\ T -1 1 1" ii l i i i j «. 4 )- i i h \ j 1 / i P p Q* .4 in C E n • \ si lu 11. J !T 0 i j ii 1 5 rl . 1. / 2 > < J s 1 P" i •i f 1 l i | 1 | | 1 1 I \ J i r , \ A If c < */• ir k i n ) I |3 1) * U • c u U — 9t ) « ft / If Q V L L b 1 f r n 9< b- s I r =l( P' v l )i BR c ir d 1 ^ e iF A Y 31 1 i 9 7* t f s r i 1 • j + i 1, j / a IC c n 1 i n e E i i* L l If IN it n J 61 C 1. i 1 y 3 9 "if ) i i \ 1 1 i 41 i 1 1 r* "V I i Ml k ii v T I 1 J l .1 »l 1 h- i f -n i I \ 1 it i l 1 | n \ • ?< > L 1 |( / t t | 1 1 1 1 1 1 1 1 1 > \ Pi 7l •\ £ n i r n r\ n J i ' t u t J c u • - vJ U Cfl 9 \ «A / J 1 > / 1C c ' 1 V U c l 1 fy • 1 u i i > 2 2 r 3 r " n r r T r \ i r \i \\ M vl 1 \ r r y T 1 1 / \ / 1 f r r } A 1 v. . r 1 \ 1 L » J r h \ rl \ 1 \ V 3 I J r 1 1 1 \ r L LV J V. >l T 1 1 \ i A I I T l A 1 I I & i \ k ) 1 r 1 1 1-r 1 1 7) 1 n 4CI Lp C 1 ie 7 i i I 11 K t K ir «J j* 1 A. i 1 F A 1 1 • • • f Si 3' r C H M 0 c \ \ 1 A\T • J 1 1 ji ni 1 T; 1 j fii 1 1 ill u \ •*i \L (I J R z ; , 11 nl Q 5 T r > 1 Ul J - S 1 n l 1 i S< ) / n ,, 1< ll r' -l \ 1 I 1 1 1 1 9 1 n or 1 •2 t 1 if k Q i /• 1 0 j 11. 1)1 J U CI 1 > s IC t \ • 11 1 t I / Si V t L U c 1 1 r i 4 1 / t 9 3 8 T' K ir r Ll rv 1 ! l\f 1 ir u H. 1 re 7/ s T PI All rw n T J N 4 ft t • • • • * • b ) c If* 0 J K > S< y 1 1^ J11 n IE n 7* n\ t • G V 71 n IL IT J e r t 31. JZ 41 X n i )• \ / n \ J j r 1 V h | | | | 1 1 | 1 | rp ( \ 1 \ in 1 p 1 \ c \e r\ m f I t r 9 r J I r u U C f 1 / c H— I 1 r T 1*' V t L c I II 23 v e l o c i t i e s . I have found that the nose v e l o c i t y i s approximately 0.7 of the average v e l o c i t y , w i t h i n the range of depths normally used f o r spawning (Figure. 7). A more accurate f u n c t i o n a l r e l a -t i o n s h i p i s suggested i n F i g u r e 8. Although, the data i s sparse with some e r r a t i c p o i n t s i t does i l l u s t r a t e a g r a p h i c a l procedure which can Be used to o b t a i n a formula expressing nose v e l o c i t y i n terms of depth and average v e l o c i t y . If one d e s i r e d , a "contoured r a t i n g " could be a p p l i e d to each of the diagrams i n F i g u r e s 4 to 6. The center, or most common p o r t i o n , of the diagram could be given the h i g h e s t r a t i n g or weight and the areas near the boundaries of the curves would have the lowest r a t i n g . Areas i n between would have i n t e r m e d i a t e r a t i n g s . An example of t h i s technique i s shown i n F i g u r e 9, f o r benthic p r o d u c t i o n . INCUBATION A f t e r the eggs are f e r t i l i z e d and b u r i e d they r e q u i r e only a few simple c o n d i t i o n s f o r s u r v i v a l . They have to remain covered by g r a v e l which does not move, they must not f r e e z e , and they need a continuous flow of w e l l oxygenated water. A f t e r about 90 days ( i n c u b a t i o n time depends on ambient temperature) the eggs hatch i n t o a l e v i n s which, continue to r e s i d e i n the i n t e r s t i t i a l spaces i n the. g r a v e l u n t i l emergen.ce i n March or A p r i l , when they Become f r e e swimmers i n the stream. 24 FIGURE 7 RELATIONSHIP OF NOSE VELOCITY TO AVERAGE VELOCITY (NECHAKO RIVER) 26 REARING The time from when the salmon leave the g r a v e l (as a l e v i n s ) , u n t i l they migrate out of the spawning stream (as smolts) i s known as the r e a r i n g phase. I t i s u s u a l l y one year but can be as long as three years (some eoho) or as short as a few days Cpink and chum). During t h i s growth p e r i o d the j u v e n i l e f i s h r e q u i r e s u i t a b l e h a b i t a t , and a constant supply of food. Cover An important requirement during the r e a r i n g p e r i o d i s cover, c o n s i s t i n g of one or more of the f o l l o w i n g : 1. Bank cover a) Streamside v e g e t a t i o n , overhanging or submerged. b) Undercut banks and r o o t systems. 2. Instrearn cover a) Logs and f l o a t i n g d e b r i s . h) Submerged rubble and b o u l d e r s . c) Aquatic p l a n t s . d) Turbulent water. J u v e n i l e f i s h , seek cover f o r s e c u r i t y a g a i n s t pred-at o r s and s h e l t e r from the c u r r e n t . They a l s o have a photonega-t i v e response which, causes them to seek shade or cover. There i s some preference f o r one. type of cover over another, depending on the species ; and the s i z e of the f i s h . 27 Each j u v e n i l e f i s h defends a t e r r i t o r y w i t h i n which i t forages f o r food. The t e r r i t o r y may change because of chang-ing flow or competition from other f i s h . Some form of cover i s necessary i n each, t e r r i t o r y f o r the f i s h to hide or r e s t , whether i t i s under a root or a bank overhang or downstream of a boulder. The p r e f e r r e d v e l o c i t i e s w i t h i n the cover zone are l e s s than 0.5 f .p.s. and the p r e f e r r e d depths are 0.5 f o o t or g r e a t e r . Wesche (19761, working with t r o u t , which have behav-i o r p a t t e r n s s i m i l a r to salmon, found t h a t : a) Minimum width, of undercut, or overhanging banks was 0.3 f e e t . b) Minimum s i z e of submerged boulder f o r use as cover was 3 inches. c) V e l o c i t y i n cover area was 0.5 f . p . s . or l e s s . d) 91.6% of j u v e n i l e s p r e f e r r e d water deeper than 0.5 f e e t . A number of other i n v e s t i g a t o r s have s t u d i e d cover, i n c l u d i n g Pearson et a l . (1970) and N i c k e l s o n (.1976). 28 Food Rearing salmon feed on fauna and d e t r i t u s small enough to i n g e s t ; t h i s Includes t e r r e s t r i a l and a q u a t i c i n s e c t s and b e n t h i c i n v e r t e b r a t e s , a broad c l a s s of aquatic fauna which i n c l u d e s some of the i n s e c t s . T e r r e s t r i a l i n s e c t s used f o r food i n c l u d e those that f a l l i n t o the water from streambank vegeta-t i o n and those which have part of t h e i r l i f e c y c l e i n water. I t i s the Benthic (bottom dwelling) i n v e r t e b r a t e s , however, which are most a f f e c t e d by changes i n flow. Many benthic i n v e r t e b r a t e s p r e f e r those c o n d i t i o n s which p r e v a i l i n r i f f l e s , that i s , a coarse g r a v e l s u b s t r a t e , r e l a t i v e l y shallow depths, and r e l a t i v e l y high v e l o c i t i e s ( F igure 9). However, the use of depth and v e l o c i t y c r i t e r i a alone to c a l c u l a t e optimum ben t h i c p r o d u c t i v i t y i s d i f f i c u l t and time consuming, and i s not made any e a s i e r by the h i g h l y v a r i a b l e c o n d i t i o n s which may occur from reach to reach i n a stream. Depth and v e l o c i t y c r i t e r i a , how-ever, can be used i n c o n j u n c t i o n with a survey of pool to r i f f l e r a t i o s . I t i s g e n e r a l l y considered that a pool to r i f f l e r a t i o of about 1:1 w i l l provide a s u i t a b l e balance between benthic food p r o d u c t i o n and r e a r i n g p r o d u c t i o n . I t i s evident that as the water l e v e l r i s e s , an optimum food producing c o n d i t i o n w i l l o b t a i n when a balance Is reached between the depth, and v e l o c i t y matrix over r i f f l e s , the pool to r i f f l e r a t i o , and the wetted width (or t o t a l amount of s u i t a b l e s u b s t r a t e covered). A great d e a l of f i e l d work may be necessary to determine t h i s optimum c o n d i t i o n . 30 General Rearing P r o d u c t i v i t y I t i s obvious, that other things being equal, the p r o d u c t i v i t y of a stream i s p r o p o r t i o n a l to i t s width. A stream twice as wide provides twice the. a q u a t i c h a b i t a t f o r both the f i s h and benthic i n v e r t e b r a t e s j twice the amount of t e r r e s t r i a l i n s e c t s are l i k e l y to f a l l i n t o the stream; the p r o d u c t i v e r i f f l e areas w i l l Be twice as wide; e t c . Although wetted width i s per-haps g e n e r a l l y recognized as the Best s i n g l e parameter of r e a r i n g p r o d u c t i v i t y , i t Is- not a s u f f i c i e n t parameter; not only i s a s u i t a b l e range of v e l o c i t i e s and depths necessary, But so i s cover, temperature, shade, t u r B i d i t y , and other water q u a l i t y and h a b i t a t f a c t o r s . F l u c t u a t i o n s , or sudden changes i n flow, may Be very d i s r u p t i v e to a r e a r i n g stream. A sudden drop i n water l e v e l w i l l cause s t r a n d i n g and r a p i d death ( p r e d a t i o n or exposure) of Both f i s h and Benthic i n v e r t e b r a t e s . I f the water l e v e l drops slowly, as normally occurs i n nature, Both f i s h and i n v e r t e b r a t e s can adapt By moving with the water. A sudden i n c r e a s e i n water l e v e l w i l l f o r c e r e a r i n g f i s h out of t h e i r normal t e r r i t o r y . They must then compete f o r new t e r r i t o r y where cover and other h a h i t a t pa-rameters are s u i t a b l e . A sudden water l e v e l i n c r e a s e w i l l a l s o d i s l o d g e the Benthic i n s e c t s . I t i s not c l e a r how important t h i s i s . The Benthic community w_ill r e e s t a b l i s h , i f there Is not t o t a l l o s s (wash, o u t ) , and the temporary Increase i n Benthic d r i f t w i l l l i k e l y Be consumed By downstream f i s h . 31 Rearing i s the most d i f f i c u l t phase of the l i f e c y c l e to q u a n t i f y . The wetted width i s g e n e r a l l y considered the best s i n g l e , e a s i l y q u a n t i f i e d parameter. Other parameters can be q u a n t i f i e d i n p r o p o r t i o n to the amount of f i e l d work undertaken, but the amount of f i e l d work can q u i c k l y become p r o h i b i t i v e . In Chapter V I I I I w i l l d e s c r i b e a procedure f o r a s s e s s i n g r e a r i n g flows which, makes- use of a l l the q u a n t i f i e d data a v a i l a b l e , c a l l s f o r a reasonable amount of f i e l d work, takes i n t o account the spe-c i a l f e a t u r e s of the stream under study, and uses the considered judgement of b i o l o g i c a l e x p e r t s . Giger CI9-73) and C o l l i n g s (1974) review r e a r i n g requirements In c o n s i d e r a b l e d e t a i l . DOWNSTREAM MIGRATION When the r e a r i n g phase i s complete the young salmon undergo a b i o l o g i c a l change, c a l l e d s m o l t i f i c a t i o n , p r e p a r a t o r y to downstream m i g r a t i o n to the sea. Downstream m i g r a t i o n u s u a l l y takes place i n l a t e s p r i n g or e a r l y summer, and i s promoted by high flows o c c u r r i n g during t h i s time. During downstream migra-t i o n there i s seldom a time when flows are so low that the smolts cannot p h y s i c a l l y swim downstream. Sometimes they may be trapped i n a pond, swamp or lake and i f the flows are i n s u f f i c i e n t they may be o b l i g e d to stay, A c e r t a i n percentage of some species do stay up to two years or more i n some streams, but i t may be f o r reasons other than u n s a t i s f a c t o r y flows. 32 CHAPTER IV STREAM HYDRAULICS SPAWNING The. h y d r a u l i c parameters which appear most important fo r spawning are depth, and v e l o c i t y . The v e l o c i t y now g e n e r a l l y r e f e r r e d to i s that at the average nose l e v e l of the spawning f i s h . For salmon t h i s has been found to be 0.4 f e e t above the stream bed. Each, species- has a range of " p r e f e r r e d " v e l o c i t i e s and depths f o r spawning ( F i g u r e s 4 to 6) — the term " p r e f e r r e d " meaning those c o n d i t i o n s most a t t r a c t i v e to the f i s h . The pre-f e r r e d v e l o c i t i e s and depths depend not only on the s p e c i e s , but a l s o on the s i z e ( f o r k length) of the f i s h . I f there i s s i g n i f -i c a n t v a r i a t i o n i n s i z e t h i s w i l l have to be taken i n t o account. Hunter (19.73) suggests that s i z e may be more important than s p e c i e s . I b e l i e v e i t i s not p r a c t i c a l to use a great amount of refinement In the measurement and a n a l y s i s of depths and v e l o c -i t i e s over a spawning ground, because of the v a r i a t i o n s i n pre-ferences w i t h i n a s p e c i e s , and the v a r i a t i o n i n v e l o c i t y which i s bound to p r e v a i l 0.4 f e e t above a coarse g r a v e l s u b s t r a t e . The presence of the spawners themselves, and the d i s t u r b a n c e to the streambed caused by the d i g g i n g a c t i v i t y , w i l l a l s o have s i g n i f -i c a n t e f f e c t on v e l o c i t y p a t t e r n s . 33 The amount of " p r e f e r r e d " spawning h a b i t a t can be determined by measuring depth and v e l o c i t y at i n t e r v a l s along one or more t r a n s e c t s and c a l c u l a t i n g the length, of t r a n s e c t or area of streambed over which the c r i t e r i a of depth and v e l o c i t y are simultaneously s a t i s f i e d . During the survey of the t r a n s e c t the g r a v e l s u b s t r a t e may be rated f o r i t s s u i t a b l l l i t y f o r spawning. This can be done by screen a n a l y s i s or by judgement of an expe-r i e n c e d observer. The sampler shown i n F i g u r e 10 i s u s e f u l f o r t h i s purpose. Each t r a n s e c t i s l o c a t e d across the stream perpendic-u l a r to the flow (Figure 11). Regular t o p o g r a p h i c a l survey pro-cedures are used to survey each t r a n s e c t . They are marked by permanent markers on each bank. The topography i s taken up to, or j u s t above, the b a n k f u l l h e i g h t . Ground e l e v a t i o n s are taken to 0.1 f t . and water su r f a c e e l e v a t i o n s to 0.01 f t . A f t e r each t r a n s e c t has been surveyed, v e l o c i t i e s and depths can be measured f o r a s e r i e s of flows (two or three w e l l separated flows are d e s i r a b l e ) using a tape s t r e t c h e d between the bank markers. Each poin t on the t r a n s e c t where the water depth and v e l o c i t y are measured i s l o c a t e d by r e c o r d i n g the d i s t a n c e on the tape from a bank marker. V e l o c i t i e s and depths should be measured at equal or n e a r l y equal i n t e r v a l s across the stream. The f i e l d procedure I use i s designed to provide data f o r the computer program, which w i l l be p r e s e n t l y d e s c r i b e d . I s e l e c t at l e a s t two separate study s i t e s In known spawning areas FIGURE 10 A SIMPLE SUBSTRATE SAMPLER TSULQUATE RIVER MINIMUM GRAVEL SIZE - 2mm (.078 inches) MAXIMUM GRAVEL SIZE - 64mm (2.52 inches) MAXIMUM COBBLE SIZE - 256mm (10.07 inches) (AMERICAN GEOPHYSICAL UNION) I SQUARE INCH SOOKE RIVER 35 FIGURE II LAYOUT OF A TYPICAL STUDY SITE TRANSECT AT RIGHT ANGLE TO STREAM BANK METERING POINTS PERMANENT TRANSECT MARKER (eg; spike in tree) • CHAIN AGE - H - - - J — J — * FROM PERMANENT MARKER METERING POINTS ALONG TRANSECT jt. EQUALLY SPACED^ STREAM WIDTH SUGGESTED SPACING (ft) OF METERING POINTS 0 — »0 1 fl 10 — 40 2 40 — 100 5 100 + 10 36 on the stream under i n v e s t i g a t i o n . The s i t e s should be i n s t r a i g h t , s t a b l e reaches i f at a l l p o s s i b l e . Three or four t r a n s e c t s are surveyed 20 to 50 f e e t apart i n each study s i t e . Using the a p p r o p r i a t e v e l o c i t y and.depth c r i t e r i a ( F igures 4 to 6). the data i s processed to a r r i v e at the area of streambed covered By the r i g h t combination of v e l o c i t y and depth. This i s done f o r each t r a n s e c t and an average spawnable area i s c a l c u l a t e d f o r the study s i t e f o r the flow under c o n s i d e r a t i o n . The flow i s a l s o c a l c u l a t e d at each t r a n s e c t . The v a r i a t i o n i n the c a l c u l a t e d flows w i l l be a measure of the accuracy of the f i e l d work and the c a l c u l a t i o n s , besides being a check of the work; although there can be u n u s u a l l y l a r g e v a r i a t i o n s i n flow between t r a n s e c t s due to interchange of s u r f a c e and subsurface flow. F i g u r e 12 shows the bed and water surface p r o f i l e along the stream c e n t e r l i n e f o r a study s i t e on the Sooke R i v e r . I t i s probable that the change i n stream flow at the t r a n s e c t s i s caused by s u r f a c e water e n t e r i n g the g r a v e l upstream of the r i f -f l e area (change i n slope of streambed) and emerging again down-stream. This i s an i d e a l s i t u a t i o n i n a spawning area and one which the spawning f i s h can sense. The procedure I have adopted f o r studying h y d r a u l i c c o n d i t i o n s In spawning areas d i f f e r s from the procedures used by other i n v e s t i g a t o r s as f o l l o w s : a) I place equal weight on the data from each t r a n s e c t by assuming that the area of the 1 7 1 c f. -tti c - i X f F f y i J V; L l i c i c s T i L 1 r \ L. 1 J t 1 | I k t .... r I •\ — I1 f 1 0 -< j -< 0 -i 0 < L> y f r / f / f « f ( u t c ^  J J t / .... \ -i R -1 H -i 0 i « i-t Q 1 | l! u. < 11 1 * \ I • a \ \ i n \ CO 1 ii i « *- 1 «i o \ 1 ( \| \ 9 \ \ 9) ( i) > O < 0 l« u. 1 , 1 I | u I • c > < l> I J c t a n m L _ a- •21! m 1 •1 / n r m / r L=I [I7J / FD M C.1 V) —i fc3 \ > \ 1 V • • I I 1 (tn \ • I; \ J. n «h TP _1 k \ 0 >\ 1 \ I i ' 4 k ( J \ —\— k - 1 V J < u 1 L r 1 < n %- I i \ c b ) c > c n t » c ) i 1 n 1 1 H A • 1 3 I r u 1 j - V / 3 1 3 38 streambed represented by each t r a n s e c t i s one foo t wide. Other methods assume that the data f o r each t r a n s e c t a p p l i e s h a l f way to adjacent t r a n s e c t s . F i r s t of a l l , i f the t r a n s e c t s are not c l o s e together Cover, say, 5' apart) t h i s i s not l i k e l y to be a v a l i d assumption. Secondly, i f the t r a n s e c t s are not e q u a l l y spaced the e f f e c t i v e , weight of the data f o r each t r a n s e c t would be d i f f e r e n t , and the end t r a n s e c t would have, h a l f the weight. 1 c a l c u l a t e the flows at each transect, to check accuracy and ob t a i n a p r o f i l e of the h y d r a u l i c c o n d i t i o n s . Other methods make no allowance f o r subsurface flows. I place emphasis on f i e l d measurements and recommend at l e a s t two, p r e f e r r a b l y three s e r i e s of measurements, i f p o s s i b l e , at d i f f e r e n t flow l e v e l s to span the flow range of i n t e r e s t . Some of the p r o f i l e methods put greater, emphasis on computer c a l c u l a t i o n s and c l a i m s u f f i c i e n t accuracy using one flow measurement and a number of to p o g r a p h i c a l surveys of t r a n s e c t s at h y d r a u l i c c o n t r o l p o i n t s . 39 d) I choose study s i t e s i n areas of the r i v e r which are u t i l i z e d By spawners. Some programs r e q u i r e that t r a n s e c t s Be taken at a l l c o n t r o l p o i n t s whether these t r a n s e c t s have b i o l o g i c a l s i g n i f i c a n c e or not. Other methods s p e c i f y a random p l a c i n g of t r a n s e c t s . Spawning and Subsurface: Flow There are a l i m i t e d number of experiments on the be-haviour of salmon when s e l e c t i n g areas of the stream f o r spawning. They appear to have a preference f o r areas where there i s a good interchange between s u r f a c e and subsurface flows. I t has been commonly observed by b i o l o g i s t s that chum salmon p r e f e r s i d e channels, or other areas where water i s u p w e l l i n g , and that sock-eye salmon o f t e n choose u p w e l l i n g areas along lake margins. Upwelling may be produced i n a number of ways, as shown i n F i g u r e s 13 and 14. Upwelling tends to occur i n a r i f f l e area ( F i g u r e 13b). Such a process i s i n d i c a t e d by the change i n measured s u r f a c e flow shown i n F i g u r e 12. Freeze and Witherspoon (.1967) d e s c r i b e the l i n e s of flow caused by a lense of higher p e r m e a b i l i t y w i t h i n s t r a t a of l e s s e r p e r m e a b i l i t y (Figure 14b), which may account f o r the f a c t that some p r e f e r r e d spawning areas are l o c a t e d i n s t r a i g h t runs. Subsurface, flow paths around boulders (Figure. 14a) have been p l o t t e d by Cooper (1965) . During an experiment with spawning chum salmon, Tautz and Groot (.19.75) 40 INTRAGRAVEL FLOW AT A REDD FIGURE 13 AND AT A POOL-RIFFLE 3. (a) PROFILE OF A REDD (b) NATURAL POOL-RIFFLE 41 FIGURE 14 INTRAGRAVEL FLOW AT A BOULDER AND NEAR A MORE PERMEABLE LENS (a) SUBSURFACE FLOW AT A BOULDER (b) SUBSURFACE FLOW PATTERN CAUSED BY A MORE PERMEABLE LENS 42 observed that they p r e f e r r e d the v i c i n i t y of upwelling flow im-mediately downstream of boulders placed i n an experimental flume. C a l c u l a t i o n of P r e f e r r e d Spawning Areas A f t e r measuring depths and v e l o c i t i e s along a number of t r a n s e c t s at one or more flow l e v e l s , a number of c a l c u l a t i o n s are necessary to o b t a i n th.e. p r e f e r r e d spawning, area. The com-puter program, Appendix A> takes care of these c a l c u l a t i o n s . In a d d i t i o n , i t w i l l i n t e r p o l a t e , and e x t r a p o l a t e f o r other flow l e v e l s not measured so that the flow l e v e l producing the maximum spawning area can be obtained ( F i g u r e 15). The program i s designed to be data dependent. I t w i l l work with the: minimum amount of data, that i s , data f o r one flow at one t r a n s e c t , c r with a l a r g e amount of data f o r s e v e r a l flow l e v e l s at s e v e r a l t r a n s e c t s . The r e l i a b i l i t y of the r e s u l t s w i l l be p r o p o r t i o n a l to the amount of input data. The f o l l o w i n g two assumptions were i n c o r p o r a t e d i n t o the program: 1. V e l o c i t y d i s t r i b u t i o n along a t r a n s e c t i s p r o p o r t i o n a l to water depth. 2. H y d r a u l i c s at each t r a n s e c t are ind e -pendent of other t r a n s e c t s . These assumptions, need e x p l a i n i n g . Examination of measured v e l o c i t y p r o f i l e s along a number of t r a n s e c t s ( F i g u r e s 16 to 18) shows- that there i s an approximate d i r e c t correspon-dence with the depth p r o f i l e s (_a m i r r o r image, adjusted to s c a l e ) . "1 r » • | f 4 0 F 1 J F 1 i f I / "3 1 \/i r < L \ \ 1 \ r 1 \c n 1 I 1 1 i • , \ T i r j T B p. < T r /• v A ") V A sl 1 sl V J A \ 1 1 / \ 1 r (• \ 1 r 1 V ) r \ l\ / n 1 r T -\ it "U 1 w L J > r" Jj UJ rr *+* T J "CD" < 4. 1 i i t pii\ j c n • l( •\t XI \/ \ / >/• ( ) J t\ H) i\ K I n ; i\ ) f :i t )\ V c f e \ I I -v i v. 1 1 44 FIGURE 16 DEPTH AND VELOCITY PROFILES TRANSECTS I TO 4 ( I 5 0 ± c f s ) o DISTANCE (ft) 45 FIGURE 17 DEPTH AND VELOCITY PROFILES TRANSECTS 5 TO 8 ( 65 ± cfs) I I I I I I I I I I I t I O 10 20 30 40 50 60 70 80 90 100 110 120 DISTANCE (ft) -r2 2^- TRANSECT 7 - 63 cfs 10 20 30 40 50 60 70 80 90 100 110 120 \ TRANSECT 6 - 6 9 cfs - i2 - I - O 30 40 50 60 70 80 90 100 110 120 130 140 Ot-"-• -r3 - 2 - I - 0 TRANSECT 5 - 8 4 cfs I 1 1 1 1 _ J I I I I I I 30 40 50 60 70 80 90 100 110 120 130 140 46 FIGURE 18 47 There may be some j u s t i f i c a t i o n i n assuming the v e l o c i t y to be p r o p o r t i o n a l to depth to the 2/3 power (by i n f e r e n c e from the Manning equa t i o n ) . The small c i r c l e s i n F i g u r e 18 are v e l o c i t y values c a l c u l a t e d u sing depth to the 2/3 power. I t can be seen, however, that t h i s produces l i t t l e i f any improvement i n the c a l -c u l a t e d v e l o c i t y p r o f i l e s . In any case, there w i l l s t i l l remain the v a r i a n c e due to i r r e g u l a r channel shapes, secondary c u r r e n t s , and changing h y d r a u l i c c o n d i t i o n s with stage. Hsieh Wen Sh.en (197 6). d e s c r i b e s a procedure f o r model-l i n g i s o v e l s f o r r e g u l a r t r a n s e c t s . Such a model should give b e t t e r r e s u l t s If i t can be adapted to i r r e g u l a r s e c t i o n s . Milhous (197 7) has been working on a way of d i s t r i b -u t i n g the v e l o c i t y over the t r a n s e c t by t r e a t i n g " i " segments (Fi g u r e 28) as separate "streams" and a p p l y i n g Mannings formula to each. He takes i n t o account the roughness of the streambed at each segment so Manning's n can be c a l c u l a t e d . His method may provide a b e t t e r approximation, but i t has not been f i e l d t e s t e d . To the extent that the flow i n a study area i s non uniform ( v a r i e d ) , assumption 2 i s not c o r r e c t . However, i f two or more flows are measured at each, t r a n s e c t , a stage d i s c h a r g e r e l a t i o n s h i p i s , i n e f f e c t , e s t a b l i s h e d f o r each t r a n s e c t . Manning's formula i s used only f o r purposes of i n t e r p o l a t i n g or e x t r a p o l a t i n g f o r other flow.s... 48 For the purpose of the computer program, Manning's n and the f r i c t i o n slope were combined to form a s i n g l e co-e f f i c i e n t , C: C A 5 7 2 1.49 sj* Q = TTTW where C = f — p2/3 n As the flow i n a n a t u r a l channel i s always non-uniform to a g r e a t e r or l e s s e r degree, the f r i c t i o n s l ope, S^, w i l l change with, discharge ( F i g u r e 19). Manning's n i s a l s o known to vary with discharge ( F i g u r e 20). However, the c o e f f i -c i e n t , C, which i n c l u d e s both these f a c t o r s , can be a c c u r a t e l y c a l c u l a t e d f o r each flow which, i s measured i n the f i e l d . When C i s p l o t t e d a g a i n s t discharge a curve i s obtained which c l o s e l y resembles the stage discharge curve ( F i g u r e s 21 and 22). The computer s t o r e s the values of C obtained by p r o c e s s i n g f i e l d data, and i n t e r p o l a t e s or e x t r a p o l a t e s a C value f o r each c a l c u l a t e d flow. C a l c u l a t e d flows check c l o s e l y with the measured flows — c e r t a i n l y w e l l w i t h i n the accuracy l i m i t s needed f o r f i s h h a b i t a t a n a l y s i s . A f t e r the average v e l o c i t y i n a v e r t i c a l i s c a l c u -l a t e d i t has to he adjusted to the nose v e l o c i t y . F i g u r e s 7 and 8 show the r e l a t i o n s h i p of nose v e l o c i t y , v^, to the average v e l o c i t y and depth ( w i t h i n the range of v e l o c i t i e s and depths i n which spawning occurs. 49 FIGURE 19 RELATIONSHIP BETWEEN ENERGY SLOPE and DISCHARGE FOR OAK CREEK, OREGON (Adapted from Milhous, 1977) o o o cP 8 o o °8_ 00 o 08 o o o o o V * o 08 8 P o o o ro o o O o J < 5 ' 3dO"IS A9U3N3 o o o o 50 FIGURE 2 0 RELATIONSHIP BETWEEN MANNING'S " n " and DISCHARGE FOR OAK CREEK, OREGON (Adapted from Milhous, 1977) fib So $ CD O „ OO o o oo 5° oo co° 8 in 6 o* fO o* CM b ..U,, S.9NINNVW 5.0i RELATIONSHIP BETWEEN " c " and DISCHARGE FOR OAK CREEK, OREGON (Adapted from Milhous, 1977) .« G . . = 1.49 S 2 n O CO o o oo o o 1.0 cn 0.21 J I I I I i i I i l I I J I I I I—L CD C JO rn 1.0 10 DISCHARGE (cfs) 100 52 FIGURE 400i STAGE DISCHARGE CURVE FOR OAK CREEK,OREGON (Adapted from Milhous, 1977) 100 CO <*-u UJ O or < X a to o 10 1.0 0.41 J I i i i J I I I I 0.5 1.0 2.0 4.0 STAGE (ft) 53 INCUBATION Salmon eggs i n a redd may be anywhere from about 6 inches to 22 inches below the streambed. The i n c u b a t i n g eggs, and the hatched a l e v i n s r e s i d i n g i n the g r a v e l , r e q u i r e a steady flow of oxygenated water. The spawners i n s t i n c t i v e l y choose per-meable g r a v e l In u p w e l l i n g or., p o s s i b l y , downwelling areas where there i s l i k e l y to be the r e q u i r e d i n t e r g r a v e l flow. The redd b u i l d i n g process- cleans: out the f i n e s so that the r e q u i r e d i n t e r -g r a v e l flow i s f u r t h e r ensured ( F i g u r e 13a). Work done on mea-sur i n g i n t e r g r a v e l flow and the a s s o c i a t e d oxygen exchange i n d i -cates that i n c u b a t i o n flows should be 75% to 100% of the spawning flows. Another way to c a l c u l a t e the Incubation flow i s to choose a water l e v e l that w i l l cover a l l the redds with f l o w i n g water. As the minimum depth f o r spawning i s about 0.6 f e e t i t i s r e a -soned that the i n c u b a t i o n flow l e v e l should not be more than 0.6 f e e t (and p r e f e r a b l y l e s s ) below the spawning flow l e v e l . The i n c u b a t i o n flow should be l a r g e enough to prevent f r e e z i n g of the redds. In very c o l d r e g i o n s , i t i s p o s s i b l e that the i n c u b a t i o n flow should be greater than the spawning flow. A f t e r h a t c h i n g , the a l e v i n s are able to move through the g r a v e l . There Is some evidence to i n d i c a t e that a slow drop i n water l e v e l , which, would be se'rlous enough to dry out the redd and k i l l the eggs, w i l l cause the a l e v i n s to move to a more f a -vourable l o c a t i o n , D i l l (1969) and Bams (19.69). 54 POOL-RIFFLE THEORY A common morp h o l o g i c a l c h a r a c t e r i s t i c of streams i s the p o o l - r i f f l e c o n f i g u r a t i o n (Figure 13b). Yang (1971) uses "the law of l e a s t time r a t e of energy expenditure" (which s t a t e s that a n a t u r a l r i v e r system chooses I t s course of flow so that the time r a t e of p o t e n t i a l energy expenditure per u n i t mass of water i s a minimum) to e x p l a i n the formation of r i f f l e s and p o o l s . He shows that a stream g r a d i e n t develops a.wavy p r o f i l e of pool r i f f l e shapes Because, i n t h i s way, the r a t e of energy expendi-ture i s minimized; and a c c o r d i n g to l a b o r a t o r y and f i e l d obser-v a t i o n s , the lengths of pools- are g r e a t e r than the lengths of r i f f l e s , i n the .condition..of s t a b i l i t y . Yang (1971) a l s o shows that the s u b s t r a t e i n the r i f f l e w i l l be coarser than the s u b s t r a t e i n the pool — a c c o r d i n g to Bagnold's (1954) theory. Bagnold d e r i v e d a formula expressing the upward r e p u l s i v e f o r c e which e x i s t s between grains, of sand or g r a v e l i n the streambed. As the r e p u l s i v e f o r c e i s p r o p o r t i o n a l to the square of the ve-l o c i t y g r a d i e n t and the square of the g r a i n diameter, l a r g e g r a i n s i z e s would tend to b u i l d up at the r i f f l e where the v e l o c i t y g r a d i e n t i s high ( F i g u r e 13b). The higher v e l o c i t i e s at the r i f -f l e tend to wash away the f i n e r p a r t i c l e s , so the net r e s u l t i s an area of coarse, permeable s u b s t r a t e with an i n t r a g r a v e l flow p a t t e r n , shown i n the f i g u r e , which, i s a t t r a c t i v e to spawning f i s h . 55 The c o n s t r u c t i o n of the redd i t s e l f tends to produce s i m i l a r h y d r a u l i c c o n d i t i o n s . that I s , the m a t e r i a l over the eggs and i n the t a i l s p i l l has been " f l u s h e d " c l e a n by the a c t i o n of d i g g i n g by the spawners. The t a i l s p i l l i s a hump which func-t i o n s i n a manner s i m i l a r to the boulder of F i g u r e 14a.. The wa-ter interchange should be v e r y s i m i l a r to the p o o l - r i f f l e i n t e r -change. F i g u r e 12 shows how the s u r f a c e flow i n c r e a s e s i n a downstream d i r e c t i o n with a p r o g r e s s i v e u p w e l l i n g i n t e n s i t y i n the r i f f l e area. HYDRAULICS OF REARING AND FOOD PRODUCTION In determining a r e a r i n g flow f o r salmon, I t i s nec-essary to understand the e f f e c t s of flows on j u v e n i l e f i s h and on food p r o d u c t i o n . Only v e l o c i t i e s and depths w i l l be d i s c u s s e d here because they are the main h y d r a u l i c parameters, but as was explained elsewhere, there are many more p h y s i c a l and b i o l o g i c a l parameters to be c o n s i d e r e d . V e l o c i t i e s and depths a s s o c i a t e d with j u v e n i l e s de-pend d i r e c t l y on the s i z e , or swimming a b i l i t y of the j u v e n i l e s . I t was found that i n the Campbell R i v e r , which i s 300 f e e t wide, j u v e n i l e s remained near the shore where v e l o c i t i e s were low. They d i s t r i b u t e d by size, out 5 or 10 f e e t from each bank — the s m a l l e s t being c l o s e s t to th.e bank, Hamilton and B u e l l (.19.74). 56 In small streams, j u v e n i l e s can d i s t r i b u t e through-out the width p r o v i d i n g v e l o c i t y i s not too high. Boulders on the streambed w i l l create areas of lower v e l o c i t i e s i n t h e i r l e e . J u v e n i l e f i s h , w i l l make quick forages out from t h i s kind of s h e l t e r . P r o d u c t i o n of benthi.c I n v e r t e b r a t e s i s a l s o dependent on v e l o c i t i e s and depths ( F i g u r e 9). I t i s not g e n e r a l l y prac-t i c a l to c a l c u l a t e areas of p r e f e r r e d r e a r i n g h a b i t a t or p r e f e r -red b e n t h i c h a b i t a t using d e p t h / v e l o c i t y c r i t e r i a because of the d i f f i c u l t y of measuring low v e l o c i t i e s i n water only a few Inches deep i n a stream strewn with, b o u l d e r s . I t may, o c c a s i o n a l l y , be worthwhile, e s p e c i a l l y f o r a major study, to s e l e c t a few r e p r e -s e n t a t i v e study s i t e s where c o n d i t i o n s are s u i t a b l e f o r taking d e t a i l e d measurements; make c a r e f u l o b s e r v a t i o n s , and apply the r e s u l t s to the whole study stream. A c o n s i d e r a b l e amount of judgement by an experienced b i o l o g i s t i s s t i l l r e q u i r e d to i n t e r -p r et the s t u d i e s and g e n e r a l i z e the r e s u l t s . UPSTREAM MIGRATION H y d r a u l i c c o n d i t i o n s may r e s t r i c t upstream m i g r a t i o n because of: a). F a l l s or steep r a p i d s which, exceed the swimming or jumping c a p a b i l i t y of the f i s h . 15.) I n s u f f i c i e n t depth, of water over f l a t Broad reaches- of r i v e r . 57 D i f f i c u l t i e s of passage at f a l l s or steep r a p i d s can be assessed by making c a r e f u l o b s e r v a t i o n s at s e v e r a l d i f f e r e n t discharges while the f i s h , are "running". Jumping success, or numbers of f i s h , passing or b.e:lng held up at the f a l l s , can be t a l l i e d . I t i s p o s s i b l e that d i f f e r e n t p a r t s of the same f a l l s may be passable at d i f f e r e n t flows. Thompson (1972) gives the f o l l o w i n g c r i t e r i a f o r up-stream m i g r a t i o n : MINIMUM MAXIMUM SPECIES DEPTH VELOCITY ( f e e t ) ( f . p . s . ) Chinook 0.8 8 Coho 0.6 8 Chum 0.6 8 Eig h t f e e t per second Is a sustained swimming speed ( F i g u r e 3), so the above c r i t e r i a a p p l i e s to long reaches. A higher water v e l o c i t y over short s e c t i o n s could be t o l e r a t e d . Thompson (1972) recommends an upstream passage flow which w i l l meet the above tabul a t e d c r i t e r i a over at l e a s t 25% of a t r a n s e c t l o c a t e d on the shallowest part of the stream. This may be a u s e f u l technique i n some cases. In B r i t i s h . Columbia, salmon m i g r a t i o n g e n e r a l l y takes place immediately a f t e r the. heavy f a l l r a i n s so low flows are not u s u a l l y a c r i t i c a l problem unless: the r a i n s are delayed or g r e a t l y reduced from the: u s u a l . There may be s p e c i a l o b s t r u c t i o n 58 problems on some r i v e r s , such as g r a v e l bar b u i l d up near the mouth, beaver dams, e t c . , so i t i s necessary to become f a m i l i a r with the c o n d i t i o n s p r e v a i l i n g along the r i v e r during m i g r a t i o n time. 59 : CHAPTER V STREAM MORPHOLOGY There are some u s e f u l r e l a t i o n s h i p s which can be de-veloped between channel h y d r a u l i c s , channel morphology and b a s i n hydrology. Channel morphology cannot be used to p r e d i c t very low flows, but i t can be used to p r e d i c t average annual flows (bank f u l l flow) when flow records are not a v a i l a b l e (Orsborn 1976). Once the average annual flow has been estimated, f i s h e r i e s r e -source maintenance flows- can be estimated u s i n g , f o r example, a modified v e r s i o n of the Montana method, Tenant (1976). The channel width, from toe of bank to toe of bank i s r e l a t e d to optimum r e a r i n g flow, which, i s u s u a l l y considered to be p r o p o r t i o n a l to the wetted width. The wetted width i n c r e a s e s r a p i d l y with discharge up to toe of bank l e v e l , then i t i n c r e a s e s at a much slower r a t e . The break i n the curve has been chosen by some i n v e s t i g a t o r s to rep r e s e n t optimum r e a r i n g c o n d i t i o n s . (Figure 23). C o l l i n g s (1974), when developing h i s r e g r e s s i o n equa-t i o n s f o r spawning and r e a r i n g flows f o r salmon, found the follow-ing channel m o r p h o l o g i c a l parameters to be the most s i g n i f i c a n t : W i d t h Cb_ a nk - f u l l ) . G ravel s i z e Reach slope. Shape f a c t o r ( b a n k - f u l l ) . H y d r a u l i c r a d i u s Cbank-full) 6 0 FIGURE 23 RELATIONSHIP BETWEEN WETTED WIDTH and DISCHARGE (SOOKE RIVER) I20h looH x o o UJ UJ 60 40 2C4i 100 200 300 400 500 DISCHARGE (cfs) 61 F i e l d i n v e n t o r y f o r low flow s t u d i e s should i n c l u d e these parameters and, as w e l l , the toe to toe width. The pool r i f f l e c o n f i g u r a t i o n i s one of the most im-portant channel c h a r a c t e r i s t i c s . The theory of t h e i r formation has been reviewed i n Chapter IV. For optimum r e a r i n g p r o d u c t i o n , water l e v e l s should be such as to give a c e r t a i n pool to r i f f l e r a t i o (1:1 Is u s u a l l y recommended). Rearing success Is dependent on benthic food p r o d u c t i o n which i s optimized by a c e r t a i n combi-n a t i o n of depths-, v e l o c i t i e s and s u b s t r a t e s i z e i n the r i f f l e areas. Giger (19.73) summarizes these requirements. A knowledge of the s u r f i c i a l geology of the r i v e r channel i s u s e f u l . H i ghly porous g r a v e l found i n a l l u v i a l fans and the s t r a t a u n d e r l y i n g the r i v e r channel o f t e n r e s u l t i n con-s i d e r a b l e interchange between su r f a c e and subsurface flows. I t i s a strong interchange of flow which c r e a t e s c o n d i t i o n s p r e f e r -red by spawning f i s h and i s necessary f o r s u c c e s s f u l egg incuba-t i o n . A p r o f i l e of low flows measured the same day at s e v e r a l p o i n t s along a r i v e r reach i s most u s e f u l and may, indeed, be necessary to i n t e r p r e t low flow c o n d i t i o n s ( F i g u r e 24). Many r i v e r systems have reaches which n a t u r a l l y go dry f o r part of most years. Yet, there may be ample water f o r f i s h l i f e i n other reaches, or other t r i b u t a r i e s , i n swamps or l a k e s . Black Creek on th.e East coast of Vancouver I s l a n d Is such a system, formed by the i n t e r - b e d d i n g of porous and impervious s t r a t a . There are over 200 swamps and lakes- i n the watershed, 63 yet much of the main channel goes dry i n l a t e summer. I t i s not at a l l p r a c t i c a l i n t h i s case to s p e c i f y instream flows i n the main channel unless they are measured at a p a r t i c u l a r l o c a t i o n on a s t a b l e reach which, has a n a t u r a l p e r e n n i a l flow. Even t h i s may not be a true measure of the p r o d u c t i v i t y of the system unless these flows are p r o p o r t i o n a l to the gross amount of water i n the sys tern. Channel shape, slope, and s u b s t r a t e s i z e help d e f i n e the a q u a t i c h a b i t a t , and each, f i s h s p e c i e s has pr e f e r e n c e s f o r a p a r t i c u l a r h a b i t a t . An understanding of the p h y s i c a l processes which produce mo r p h o l o g i c a l changes w i l l help p r e d i c t the changes i n h a b i t a t , and the consequent r e d i s t r i b u t i o n of the f i s h , due to a major change i n the flow regime as may, f o r example, be caused by c o n s t r u c t i o n of a dam. 64 CHAPTER VI HYDROLOGY Before d i s c u s s i n g the use of the annual hydrograph i n low flow a n a l y s i s i t Is worthwhile to d e s c r i b e the r e l a t i o n s h i p between the annual hydrograph ( F i g u r e 25) and the freshwater l i f e c y c l e of the salmon. MIGRATION AND SPAWNING Adult salmon r e t u r n i n g from the ocean to spawn i n B r i t i s h Columbia's c o a s t a l r i v e r s g e n e r a l l y migrate upstream during the months of August to December. As August to October can be very dry months there may be i n s u f f i c i e n t water depth f o r passage. If t h i s i s the case, the salmon, w i l l stay i n " r e s t i n g p o o l s " i n the lower r i v e r or i n the estuary u n t i l they are a t t r a c t e d up-stream by the f a l l r a i n s , which g e n e r a l l y come i n l a t e October or e a r l y November, as shown by the peaks on the hydrographs. If the a t t r a c t i o n flows are weak or the water depths remain I n s u f f i c i e n t f o r ready passage and the w a i t i n g f i s h are approaching spawning m a t u r i t y ("ripening") they may swim upstream as f a r as p h y s i c a l l y p o s s i b l e and spawn i n areas short of t h e i r p r e f e r r e d g o a l , or they may enter side channels or t r i b u t a r y streams. In some cases th.ey w i l l work t h e i r way upstream from pool to pool as flow c o n d i t i o n s permit, Spawning g e n e r a l l y takes place i n the months October to December. N a t u r a l r i v e r flows 66 during these months are u s u a l l y h i g h l y v a r i a b l e . I t i s not c l e a r l y understood how w e l l the salmon are adapted to such v a r i -a t i o n s . I t i s known that spawners are d i s r u p t e d by sudden drops or r i s e s i n flow l e v e l s , such as may occur below h y d r o - e l e c t r i c p l a n t s , but i f the r a t e of change of flow i s not g r e a t e r than found i n the n a t u r a l r i v e r from r a i n f a l l , the spawners can appar-e n t l y adjust without d i s t r e s s or d i s o r i e n t a t i o n , Hamilton and B u e l l (1976). There i s a common assumption that there e x i s t s an i d e a l uniform flow, or narrow range of " p r e f e r r e d " flows f o r spawning. The success of spawning i n a r t i f i c i a l spawning chan-nels with, r e g u l a t e d flows seems to s u b s t a n t i a t e t h i s . The ques-t i o n could be r a i s e d , however, whether i t i s not more a matter of the u n i f o r m i t y of the a r t i f i c i a l bed and an a d a p t a t i o n of the f i s h to the uniform flow. In n a t u r a l r i v e r s , bed topography i s i r r e g -u l a r , and so are the flows during spawning time. P r e f e r r e d spawning c o n d i t i o n s w i l l , t h e r e f o r e , p r e v a i l i n d i f f e r e n t p a r t s of the r i v e r at d i f f e r e n t times. This n a t u r a l v a r i a b i l i t y w i l l ensure some spawning success over a f a i r l y wide range of flows. A n a t u r a l consequence i s that eggs deposited i n one area at a c e r -t a i n stage of flow w i l l l e s s l i k e l y be d i s t u r b e d by s u c c e s s i v e spawners because changing stages of flow w i l l l i k e l y have a t -t r a c t e d them elsewhere. Another advantage of t h i s n a t u r a l d i v e r -s i t y i s that eggs w i l l be d eposited at a v a r i e t y of l e v e l s so that there w i l l be a b e t t e r chance of s u r v i v a l through subsequent extremes of f l o o d flows or low water f r e e z i n g c o n d i t i o n s . 67 In c o a s t a l B r i t i s h . Columbia r i v e r s , flow extremes, both high and low, are common during the spawning p e r i o d . Flow c o n t r o l by an upstream r e s e r v o i r can be b e n e f i c i a l by: a) reducing peak flows which cause spawners to spawn on higher bars, which subsequently go dry. b) Augmenting low flows so a greater area of spawning ground becomes a v a i l a b l e . INCUBATION Incubation covers the p e r i o d from spawning to emer-gence, i n March or A p r i l . The eggs and a l e v i n s are very suscep-t i b l e to both very low and very high flows, both of which can occur In the i n c u b a t i o n p e r i o d , see F i g u r e 25. Very low flows are a s s o c i a t e d with reduced oxygen t r a n s f e r and f r e e z i n g c o n d i -t i o n s . Eggs and newly hatched a l e v i n s cannot t o l e r a t e dryness or s t i l l water. There i s some evidence that o l d e r a l e v i n s , D i l l CL969) , Bams (1969.), l i v i n g w i t h i n the i n t e r g r a v e l spaces can move down or sideways i n the g r a v e l towards the stream c e n t e r l i n e . Very high flows cause g r a v e l movement and washout of eggs and a l e v i n s . I t i s evident th.at c o n t r o l l e d flows (higher minimum flows-and reduced f l o o d peaking) would be b e n e f i c i a l during the i n c u b a t i o n p e r i o d . 68 Once the a l e v i n s have l e f t the g r a v e l to become f r e e swimming (March and A p r i l ) , high flows are b e n e f i c i a l , They w i l l encourage downstream m i g r a t i o n of smolts, and cleanse the g r a v e l i n the spawning beds. REARING The p e r i o d May to September completes the annual c y c l e . This p e r i o d i s the beginning of the r e a r i n g phase of those s p e c i e s which remain i n the r i v e r system. Coho j u v e n i l e s , f o r example, rear i n the stream f o r a year or more before going to sea. Chum j u v e n i l e s , on the other hand, leave the r i v e r a l -most immediately a f t e r emergence;. The lowest and most prolonged low flows are l i k e l y to occur In the r e a r i n g p e r i o d . B i o l o g i s t s g e n e r a l l y agree that the p r o d u c t i v i t y of the stream i s f r e q u e n t l y governed by the lowest flow during t h i s p e r i o d . Low flows l i m i t the amount of a q u a t i c h a b i t a t , and as each f i s h r e q u i r e s a c e r -t a i n amount of space, cover and food f o r s u r v i v a l , l i m i t e d h a b i -t a t means l i m i t e d f i s h s u r v i v a l and p r o d u c t i o n . A s s o c i a t e d with low flows are low food p r o d u c t i o n , high temperatures, reduced cover, and higher c o n c e n t r a t i o n s of p o l l u t a n t s . The more extended the low flow p e r i o d , the l e s s i s the chance f o r s u r v i v a l of the r e a r i n g j u v e n i l e s . In very dry weather and i n c e r t a i n reaches of streams the s u r f a c e flow may cease, l e a v i n g only pools which grad-u a l l y dry up. Fish, can s u r v i v e f o r short p e r i o d s i n pools but a l l the adverse c o n d i t i o n s mentioned above i n c r e a s e i n s e v e r i t y 69 to cause r a p i d m o r t a l i t y of the trapped f i s h . Because of t h e i r m o b i l i t y , j u v e n i l e s can s u r v i v e , to some extent, short periods of higher s t r e s s occasioned by low flows. They may move to other t r i b u t a r i e s of the r i v e r ; or f i n d c o o l e r water i n deep pools, under undercut banks, or even w i t h i n the g r a v e l s u b s t r a t e of the stream bed. Food pr o d u c t i o n w i l l be d r a s t i c a l l y reduced as flows over p r o d u c t i v e r i f f l e s d i m i n i s h e s . McKernan et a l . (1950) has shown that there i s a p o s i t i v e r e l a t i o n s h i p between summer flow c o n d i t i o n s and numbers of r e t u r n i n g a d u l t s . The lowest mean monthly flow is- sometimes considered to govern r e a r i n g produce t i v i t y . . This may be a s a t i s f a c t o r y r u l e of thumb f o r some streams but i t may take only a few days of extreme low flow to decimate the p o p u l a t i o n : The. 7 day low flow p e r i o d i s now beginning to be used i n low flow a n a l y s i s , perhaps p a r t l y because of the a v a i l -a b i l i t y of 7 day low flow frequency curves. I t may s t i l l not be a short enough p e r i o d to co n s i d e r f o r some s i t u a t i o n s where low flows l a s t i n g only a day or l e s s could be d i s a s t r o u s . C a r e f u l study of s e v e r a l years of hydrographs i n r e l a t i o n to the l i f e c y c l e s of the salmon s p e c i f i c to the study stream p r o v i d e s , I be-l i e v e , the necessary b a s i c understanding of the. n a t u r a l flow requirements: through the year. There are many v a r i a t i o n s to the annual h i s t o r y of fresh., water r e s i d e n c e of salmon and t h e i r adap-t a t i o n to the flow regime. Each, species has d i f f e r e n t timing and pr e f e r e n c e s . There are a l s o timing d i f f e r e n c e s - between r i v e r systems-. In a d d i t i o n , there are year to year d i f f e r e n c e s i n timing i n the same r i v e r system. 70 The f o r e g o i n g d i s c u s s i o n Leads us to c e r t a i n general c o n c l u s i o n s as to the degree to which the n a t u r a l flows, as shown i n the hydrograph, might Be a l t e r e d to improve f i s h e r y p r o d u c t i v -ity.;. 1. Peak flows could be reduced, as by d i v e r s i o n s , during spawning and i n c u b a t i o n p e r i o d s . 2. Low winter flows should be augmented so the flow never drops below the safe l e v e l s r e -quired f o r i n c u b a t i o n , and over winter r e a r i n g . 3. Summer and f a l l low flows should be augmented up to the optimum l e v e l s determined from f i e l d s t u d i e s . Any i n c r e a s e i n flows during natu-r a l l y dry p e r i o d s i s , almost without r e s e r v a -t i o n s , b e n e f i c i a l . 4. E l i m i n a t e sudden changes i n flows as, f o r example, may occur downstream of hydro e l e c t r i c power p l a n t s . 5. M a i n t a i n spawning flows w i t h i n c e r t a i n l i m i t s . I f spawning takes p l a c e at too high a flow the subsequent i n c u b a t i o n flows may be i n s u f f i c i e n t to cover a l l the redds. 6. M a i n t a i n peak, flows j u s t p r i o r to upstream m i g r a t i o n f o r a t t r a c t i o n water, and j u s t a f t e r ermergence to cleanse g r a v e l and encourage downstream m i g r a t i o n . 71 GAGED WATERSHEDS When surface r u n - o f f data i s a v a i l a b l e the f o l l o w i n g types of analyses can be performed. 1. Hydrograph a n a l y s i s . 2 . Storage c a l c u l a t i o n s . 3 . Frequency a n a l y s i s . 4 . C o r r e l a t i o n a n a l y s i s . I f there are many years of r e c o r d s , say 10 or more, then a way of proceeding i s as f o l l o w s : a) Examine the p l o t t e d hydrographs, keeping i n mind the l i f e c y c l e timing. Estimate spawning, i n c u b a t i o n , r e a r i n g , and passage flows; draw h o r i z o n t a l l i n e s at these values on the hy-: drographs of 2 or 3 of the d r i e s t years and estimate the storage or augmentation r e q u i r e d to maintain these t e n t a t i v e l y chosen flows. They should he r e a l i s t i c f o r the watershed system under study. S e v e r a l estimates may be necessary depending on the experience of the a n a l y s t and the complexity of the system. U s u a l l y there are already major water users d i v e r t i n g water from the r i v e r , and o f t e n there i s some developed storage. The e x i s t -ing r i g h t s and the i n f l u e n c e they may have on the hydrographs have to he considered. 15). Do s u f f i c i e n t f i e l d work to confirm, or amend the t e n t a t i v e f i s h e r y flow v a l u e s so f a r developed. Enough informa-t i o n should be obtained so that some incremental a n a l y s i s can be done (Chapter V i l l i . I f the f i e l d values turn out to be e n t i r e l y 72 d i f f e r e n t from those obtained by hydrograph a n a l y s i s a r e v i s i o n of the hydrograph a n a l y s i s i s i n d i c a t e d . There are always nat-u r a l l i m i t s to the water a v a i l a b l e from a given watershed so a balance has to be s t r u c k between what might be the optimum flows determined from f i e l d s t u d i e s , u sing h a b i t a t c r i t e r i a , and the a b i l i t y of the watershed to supply these flows, as determined from the hydrographs and t a k i n g Into account other e x i s t i n g and Cpossibly). f u t u r e b e n e f i c i a l water uses. c) The 7 day minimum flow frequency c h a r t s of Water Survey of Canada Q.974), and the formulas of C o l l i n g s and Orsborn can be compared with the hydrograph and f i e l d data a n a l y s e s . I f they f i t , they are tending to confirm the r e s u l t s . I f they do not f i t then the reasons should be explored. F a m i l i a r i t y with the formulas and the watershed hydrology i s very u s e f u l . I n f o r -mation obtained may be c o r r e l a t e d and extended to other water-sheds (gaged and ungaged). d) In r e l a t i n g the hydrographs to the f i e l d work i t i s imperative that the r e l a t i o n s h i p s between flows at the gaging s t a t i o n and the study areas are known. Large d i f f e r e n c e s i n flow along a r i v e r are p o s s i b l e , even i n short d i s t a n c e s , p a r t i c u l a r l y d uring times of low flow. e) F i n a l l y , e x i s t i n g water d i v e r s i o n s , proposed major water d i v e r s i o n s , present storage f a c i l i t i e s and proposed and p o t e n t i a l storage f a c i l i t i e s must a l l be considered to see how the F i s h e r i e s Resource Maintenance. Flows, so f a r determined, can be r e a l i s t i c a l l y a t t a i n e d , U s u a l l y compromises are necessary. 73 In p r a c t i c e these steps are not c l e a r l y separate; they are done more or l e s s c o n c u r r e n t l y . The most s a t i s f a c t o r y s o l u t i o n i s one i n which, the hydrology i s i n good agreement with f i e l d data and e x i s t i n g water use c o n s t r a i n t s . The c o n f l i c t be-tween d i f f e r e n t b e n e f i c i a l uses of water, and the means of p r e -sen t i n g a case f o r instream use of water f o r f i s h e r i e s with the a i d of incremental a n a l y s i s w i l l be covered i n Chapter V I I I . I f there are. only a few years of r e c o r d s , c o r r e l a -t i o n s can be made with nearby watersheds which may have longer periods of r e c o r d s . Frequency a n a l y s i s can be e f f e c t i v e l y ex-tended In this- way. The fewer the records a v a i l a b l e f o r the watershed the more i t w i l l have to be t r e a t e d as ungaged. UNGAGED WATERSHEDS The best approach to the study of an ungaged water-shed i s to i n s t a l l one or more gages and o b t a i n one or more years of d a i l y flow data. Even data f o r a few days or months, espe-c i a l l y i f obtained during the dry p e r i o d of the year, can be very u s e f u l . I f gages cannot be i n s t a l l e d and flow data obtained be-cause of l i m i t e d time, or some other c o n s t r a i n t , then the stream flow should be metered at s e v e r a l l o c a t i o n s f o r s e v e r a l flows. At l e a s t three sets of -meterings f o r three w e l l separated stages should be obtained and at l e a s t one s t a f f gage should be i n s t a l -l e d . The gageCs), are read e.a.ch, time the stream i s metered so a stage d i s c h a r g e curve can be prepared f o r use i n l a t e r flow 7 4 a n a l y s i s f o r spawning and other l i f e c y c l e a c t i v i t i e s . Riggs (1969) presents a method of c o n s t r u c t i n g a monthly hydrograph from a s e r i e s of meterings taken at l e a s t once every month f o r a year . Meterings should be done at s e v e r a l p o i n t s along the stream l e n g t h during low flow periods to o b t a i n a l o n g i t u d i n a l flow p r o f i l e . There can be. l a r g e d i f f e r e n c e s i n flow form one point to another, as F i g u r e s 24 and 26 show, and t h i s can have s i g n i f i c a n t e f f e c t on the f i s h e r y . F i e l d work procedures d e s c r i b e d i n Chapter IV can be used f o r both gaged and ungaged watersheds. Study areas, metering s i t e s , and gage i n s t a l l a t i o n s are common to both. I t may not be easy to judge, at the beginning of a p r o j e c t , the amount of f i e l d -work necessary, so i t i s a good plan to set up permanent gages and t r a n s e c t markers f o r f u t u r e use and r e f e r e n c e . There are a few techniques a v a i l a b l e f o r e s t i m a t i n g low flows when no records are a v a i l a b l e . Orsborn (1976) and Stalnaker (1976) have reviewed t h i s s u b j e c t . Orsborn d e s c r i b e s the development of low flow a n a l y s i s methods, where i t has been found that c o r r e l a t i o n and r e g r e s s i o n a n a l y s i s , although reason-ably s u c c e s s f u l f o r f l o o d flows, Is not very s u c c e s s f u l f o r pre-d i c t i o n of low flows. To overcome t h i s problem, Orsborn d e v e l -oped what he c a l l s an output-output a n a l y s i s based on b a s i n para-meters and the c o n s t r u c t i o n of the 7 day low flow r e c u r r e n c e I n t e r v a l graph, u t i l i z i n g records and c h a r a c t e r i s t i c s of other SALMON RIVER FLOW PROFILE SEPTEMBER, 1975 (Adapted from Obedkoff, 1976) 90 80 70 60 50 40 30 20 10 0 DISTANCE (miles) o c m rv> 76 basins i n the same h y d r o l o g i c a l r e g i o n . As Riggs (1972) and others d i s c o v e r e d , i t i s d i f f i c u l t to d e r i v e r e l i a b l e r e g r e s s i o n equations e x p r e s s i n g low flow as a f u n c t i o n of b a s i n parameters. Orsborn r e c o g n i z i n g • t h i s . d i f f i c u l t y , e l e c t e d to use only a few of the most important and Independent b a s i n parameters, and then strengthen the p r e d i c t a b i l i t y by using r e l a t i o n s h i p s between the b a s i n parameters: and the 7 day low flow r e c u r r e n c e i n t e r v a l graphs of nearby gaged watersheds. He compares- the r e s u l t s he obtains f o r 7 day low flows (outputs) from s e v e r a l f u n c t i o n a l . r e l a t i o n s h i p s and r e e s t i m a t e s and :r-e'lt,e:ri.a.tes i f they are not i n s a t i s f a c t o r y agreement. Mis-; • c e l l a n e o u s meterings can be used to check and improve the r e s u l t s . In Appendix C I have given a d e t a i l e d , step by step procedure f o r an a c t u a l problem, based on h i s technique. A map of Vancouver I s l a n d (part of which i s shown i n F i g u r e 27) was prepared as an a i d i n the a n a l y s i s of ungaged watersheds. I s o h y e t a l l i n e s were p l o t t e d using l a t e s t p r e c i p i -t a t i o n data, and a d i v i s i o n i n t o regions was made by c o n s i d e r i n g p r e c i p i t a t i o n p a t t e r n s and the b i o g e o c l i m a t i c zonation developed by K r a j i n a . This map has been used to analyse flows f o r the ungaged Tsulquate River and compare flows In the ungaged t r i b u -t a r i e s of the Sooke R i v e r . C o l l i n g s (JL9.7 4).. has, d e r i v e d r e g r e s s i o n equations, based on b a s i n and stream channel parameters, which give estim-ates of flows r e q u i r e d f o r spawning and r e a r i n g . His equations 78 are not estimates of low flows; they are estimates of flows needed f o r optimum f i s h e r y p r o d u c t i o n (which are much grea t e r than 7 day low f l o w s ) . Because he was working with more average flows, he obtained a reasonable degree of c o r r e l a t i o n . the s t a n -dard e r r o r of h i s equations ranges between 24% and 60%. In Appendix B I have provided c a l c u l a t i o n s f o r s e v e r a l streams using h i s formulae, and I n d i c a t e d the degree of correspondence a t t a i n e d with, the r e s u l t s from other methods. Tennant ("19.7 61 has developed a method f o r e s t i m a t i n g f i s h e r i e s resource flows based on the average annual flow. His work was done on streams i n the Midwest, Great P l a i n s , and I n t e r -mountain West areas of the United S t a t e s ; so, although h i s r e s u l t s do not apply d i r e c t l y to B. C, streams, h i s technique bears con-s i d e r a t i o n . He found that c e r t a i n percentages of the average annual flow provided s u i t a b l e flows f o r the v a r i o u s phases of the f r e s h water l i f e c y c l e . They are as f o l l o w s : Recommended Base N a r r a t i v e F l o w R e g i m e n s D e s c r i p t i o n of Flows Oct.-Mar. Apr.-Sept F l u s h i n g Flow Optimum Range Outstanding E x c e l l e n t Good F a i r Poor or MinImum Severe Degradation 200% of the Average Flow 60%-100% of the Average Flow 40% 60% 30% 50% 20% 40% 10% 30% 10% 10% 10% of Average Flow to Zero F l 79 Tennant's method was proposed f o r e a s t e r n Canada by C u l l e n and Ducharme (1976), but with c o n s i d e r a b l e m o d i f i c a t i o n o percentages. The above techniques can be used f o r p r e l i m i n a r y s t u d i e s and f o r checking and comparing flow requirements d e r i v e d by other means. They become more r e l i a b l e and u s e f u l when adjusted to the h y d r o l o g i c a l r e g i o n and to m i s c e l l a n e o u s records and measurements. 80 CHAPTER VII TECHNIQUES AND METHODOLOGIES A "methodology" Is commonly meant to mean a body of techniques used f o r a systematic i n q u i r y . There are three main types of methodologies used to c a l c u l a t e the flows r e q u i r e d to optimize f i s h e r y p r o d u c t i v i t y , or to b r i n g about a s p e c i f i c l e v e l of p r o d u c t i v i t y : 1), B i o l o g i c a l type - may be simple ( o p i n i o n and experience) to complex (exhaustive sampling and a n a l y s i s ) . 2) H y d r o l o g i c a l type - may be simple to complex. L i t t l e or no b i o l o g i c a l inpu t. 3) Combined type - simple ( b i o l o g i c a l o p i n i o n backed up by simple engineer-ing input) to complex (exhaustive b i o - e n g i n e e r i n g s t u d i e s ) . A l l types are i n use. The f i r s t type i s the one of t e n used by b i o l o g i s t s ; f r e q u e n t l y , the h y d r o l o g i c a l , h y d r a u l i c and morphological aspects are Ignored or misunderstood. The sec-ond type i s used by engineers because they understand hydrology, h y d r a u l i c s and stream morphology but u s u a l l y know very l i t t l e about b i o l o g y . The combined type combines the best f e a t u r e s of the f i r s t two and e l i m i n a t e s t h e i r short comings. 81 The t o t a l methodology or proceedure f o r e s t a b l i s h i n g f i s h e r y flows w i l l be d i s c u s s e d i n Chapter IX. Here, I w i l l d i s c u s s only those techniques which cover the way data i s c o l l e c t -ed and analyzed. I w i l l not cover the aspects of p r i o r water r i g h t s , s t a t u t o r y powers, or economic v a l u e s , although they are necessary i n a complete, f i s h e r i e s flow methodology. Stalnak.er and Ar n e t t e (1976) have reviewed techniques and methodologies f o r determining flow requirements f o r f i s h , proposed or i n present use, i n the United S t a t e s . A number of the techniques are common to the v a r i o u s methodologies, and the s e v e r a l phases of the l i f e c y c l e are g e n e r a l l y t r e a t e d s e p a r a t e l y . So, r a t h e r than d i s c u s s each methodology i n d i v i d u a l l y , I have chosen to d i s c u s s the v a r i o u s techniques under the headings of the l i f e c y c l e phases. UP STREAM MIGRATION There are two ways of c a l c u l a t i n g the flow r e q u i r e d f o r upstream m i g r a t i o n . 1. B i o l o g i s t s watch, the f i s h move upstream, and by knowing the flow at the time of ob s e r v a t i o n , can judge the minimum flow n e e d e.d . 2. Transects of the r i v e r are taken at p o i n t s of c r i t i c a l passage, and assessed, as f o l l o w s , Thompson (1972) : 82 a) The t r a n s e c t i s l a i d out on the shallowest route across the r i v e r . b) Depths and v e l o c i t i e s are mea-sured along the t r a n s e c t at i n t e r v a l s . c)_ The l e n g t h of t r a n s e c t meeting the passage c r i t e r i a i s c a l c u l a t e d . Recommended passage flow i s that which meets the depth v e l o c i t y c r i t e r i a over at l e a s t 25% of the t r a n s e c t l e n g t h ; f o r t y percent of t h i s q u a l i f y i n g length, to be contiguous. I b e l i e v e that, f o r salmon, the f i r s t method i s to be p r e f e r r e d because the b i o l o g i s t can f a m i l i a r i z e h i m s e l f with a l l the unique passage problems throughout the m i g r a t i o n l e n g t h of the r i v e r . U s u a l l y , passage problems a r i s e at dams, c u l v e r t s , f a l l s , and r a p i d s ; not at r i f f l e areas, f o r which method 2 has been developed. Sometimes, passage i s d i f f i c u l t over broad f l a t bar or r i f f l e areas i n the lower reaches of r i v e r s . A p p l i c a t i o n of method 2 i n additon to, not i n l i e u of, method 1 could be u s e f u l i n such cases. 83 SPAWNING The use of v e l o c i t y / d e p t h c r i t e r i a ( F i g u r e s 4 to 6) i s almost the standard technique f o r c a l c u l a t i n g spawning flow. There are a number of v a r i a t i o n s which are d e s c r i b e d by Stalnaker and Arnette (19.76). The usual technique i s to set out s e v e r a l t r a n s e c t s across the spawning grounds and measure depths and ve-l o c i t i e s at a number of p o i n t s on each t r a n s e c t . This i s done fo r s e v e r a l flows and a graph Is prepared showing spawnable area versus flow ( F i g u r e 15) . Th.e. high p o i n t on the graph i s the optimum flow. This Is a u s e f u l technique. I use I t on every study i n the f o l l o w i n g way: A b i o l o g i s t determines the range or d i s -t r i b u t i o n of spawners i n the system under study. Two or three t y p i c a l spawning s i t e s are s e l e c t e d f o r "study areas" arid three or four t r a n s e c t s are surveyed about 25' to 50' apart i n each study area (Figure 11). Depths and v e l o c i t i e s are measured at s e v e r a l flows, as p r e v i o u s l y d e s c r i b e d , and analyzed and p l o t t e d . The b i o l o g i s t i s present d u r i n g some or a l l of t h i s work so that h i s o b s e r v a t i o n s can be used to c o r r o b o r a t e or augment the f i n d -i n g s . At l e a s t some of the work should be done during spawning season when spawners are present, to f u r t h e r c o r r o b o r a t e the r e s u l t s . 84 INCUBATION One way of determining the minimum i n c u b a t i o n flow Is simply to c a l c u l a t e the flow necessary to cover the redds with flowing water. As the minimum spawning depth i s about 0.6 f e e t , an i n c u b a t i o n flow l e v e l 3 or 4 Inches below the spawning l e v e l should be s a t i s f a c t o r y . Thompson (1972) found from a number of experiments i n Oregon that an i n c u b a t i o n flow 2/3 of the spawning flow i s s a t i s f a c t o r y . To be on the safe s i d e , a flow l e v e l equal to the spawning l e v e l can be s p e c i f i e d . I t should be kept i n mind that the i n c u b a t i o n flow must be d i r e c t l y r e l a t e d to the spawning flow. I f there i s a l i m i t to the flow a v a i l a b l e during the time of i n c u b a t i o n then the spawning flow may have to be adjusted downward. Measurements of i n t r a - g r a v e l flow r a t e s and oxygen content of subsurface water have been made by s e v e r a l i n v e s t i g a -t o r s (reported i n Stalnaker and A r n e t t e , 1976). Such measurements could be made In s e l e c t e d spawning areas at s e v e r a l flow l e v e l s . An i n c u b a t i o n flow l e v e l could then be chosen which would ensure a s u i t a b l e r a t e of oxygen t r a n s f e r . To date, the a v a i l a b l e procedures have i n v o l v e d a great deal of work and have not been e n t i r e l y r e l i a b l e . However, the P a c i f i c Northwest F o r e s t and Range E x p e r i m i n t a l S t a t i o n i n Juneau, A l a s k a , i s working on an insrument to measure, i n t r a - g r a v e l flow, based on the hot wire flow meter theory, which, may prove pr act l e a l . 85 REARING A number of techniques have been used to assess the e f f e c t s of flow on r e a r i n g salmon. They can be grouped, a c c o r d -ing to how the emphasis Is p l a c e d , i n t o three general c a t a g o r l e s : 1. Food P r o d u c t i o n p o o l - r l f f l e r a t i o s v e l o c i t i e s and depths i n r i f f l e s b enthic sampling d r i f t sampling areas or widths of r i f f l e s s u b s t r a t e i n r i f f l e s p o o l - r i f f l e r a t i o s v e l o c i t i e s and depths, swim speeds bank cover s u b s t r a t e , instream cover, r e s t i n g areas wetted width p o o l - r i f f l e r a t i o s bank cover s u b s t r a t e sh.ade wetted width ju v e n i l e , sampling, shocking 2 . J u v e n i l e H a b i t a t 3 . Inventory 86 Food p r o d u c t i o n i s assessed by measuring depths and v e l o c i t i e s i n r i f f l e s , and c a l c u l a t i n g the widths or areas covered by combinations of depths and v e l o c i t i e s f a l l i n g w i t h i n the range of benthic p r o d u c t i o n c r i t e r i a ( F i gure 9). Benthic and d r i f t sampling, and s u b s t r a t e sampling a i d i n the a n a l y s i s . The pool to r i f f l e r a t i o i s a measure of the balance of food use to food p r o d u c t i o n . S u i t a b l e j u v e n i l e , h a b i t a t , which i s an i n d i c a t o r of p o t e n t i a l p r o d u c t i v i t y , i s assessed by measuring depths and ve-l o c i t i e s along t r a n s e c t s or i n a g r i d and a p p l y i n g r e a r i n g v e l o c -i t y depth c r i t e r i a . Bank cover and a s s o c i a t e d depths and v e l o c -i t i e s ; and instream cover, u s u a l l y provided by l a r g e s u b s t r a t e m a t e r i a l , can a l s o be measured. The wetted width, alone, i s o f t e n used as a measure of j u v e n i l e p r o d u c t i o n . I t i s probably the best s i n g l e i n d i c a t o r of p o t e n t i a l p r o d u c t i v i t y . Inventory techniques i n c l u d e measurements of a number of the parameters already mentioned; but can, as w e l l , cover a d d i -t i o n a l f e a t u r e s , such as: shade, canopy overhang, and o r i e n t a t i o n of the stream. T e r r e s t r i a l and a e r i a l photos may a l s o be used. Standing crop of j u v e n i l e s can be estimated by shock sampling. Stalnaker and Ar.nette (.1976) have reviewed the r e a r -ing assessment techniques: c u r r e n t l y being used. Some techniques concentrate on food p r o d u c t i o n , some on d e t a i l e d v e l o c i t y depth measurements, others on an i n v e n t o r y approach., e t c . Each tech-nique w i l l provide some, assessment of j u v e n i l e p r o d u c t i o n , or 87 p o t e n t i a l p r o d u c t i o n . The r e l i a b i l i t y of the technique w i l l depend on: 1. The nature of the stream being s t u d i e d . 2. The f i s h , species, being s t u d i e d . 3 . TR.e scope, or number of parameters. 4. The accuracy of the measurements. 5 . The experience of the observers. Some techniques are r a t h e r s p e c i f i c . A technique emphasizing food p r o d u c t i o n i s not l i k e l y to be v a l i d unless food p r o d u c t i o n governs o v e r a l l p r o d u c t i v i t y . A technique based on measurement of bank cover should not be used f o r those species which do not depend p r i m a r i l y on bank cover. I t takes c o n s i d e r -able b i o l o g i c a l experience to know which techniques are most s u i t a b l e f o r a p a r t i c u l a r case. A f u r t h e r d i f f i c u l t y may a r i s e because of changing h a b i t a t conditons with changing stages of flow. Food p r o d u c t i o n may govern at some flows, bank cover may govern at other flows. The procedure f o r a s s e s s i n g r e a r i n g f l o w s , which I propose, makes use of a l l a v a i l a b l e techniques and takes i n t o account the knowledge, and judgement of the observers; t h i s w i l l be explored i n more d e t a i l i n Chapter V I I I . The f i e l d procedure i s as f o l l o w s : 1. The b i o l o g i s t makes a reconnaisance of the system to determine r e a r i n g d i s t r i b u t i o n , and s e l e c t s s e v e r a l t y p i c a l areas f o r d e t a i l e d study. 88 A water l e v e l gage i s i n s t a l l e d i n or near each chosen study area, and stage d i s c h a r g e curves are prepared. At l e a s t one t r a n s e c t i s surveyed across each study area and r e f e r e n c e d on each bank by a permanent marker. The b a n k f u l l width and toe f u l l width, i s measured at each t r a n s e c t . A simple i n v e n t o r y Is made of each study area, to i n c l u d e : g r a v e l sampling, photo-graphs-, sketches of overhead and bank cover, b a n k f u l l width, toe f u l l width, water width and reach s l o p e . A b i o l o g i c a l assessment i s made of r e a r i n g c o n d i t i o n s , f o r s e v e r a l flow l e v e l s , i n each study area. Assessments should be done f o r flow l e v e l s below, near, and above the toe f u l l l e v e l . The gages are read during each assessment so the flow w i l l be known. During each assessment, the depths and v e l o c i t i e s along each t r a n s e c t should be measured. The b i o l o g i s t C s ) making the assessments must keep i n mind that he w i l l need to r a t e the p r o d u c t i v i t y at each flow l e v e l f o r p r e p a r a t i o n of u t i l i t y curves f o r incremental a n a l y s i s (Chapter V I I I ) . 89 Step 5 may c o n s i s t of a quick a p p r a i s a l , or a thor-ough, d e t a i l e d b i o l o g i c a l study. The amount of work w i l l depend on the time and funds a v a i l a b l e , and the r e l a t i v e importance of the p r o j e c t . DOWNSTREAM MIGRATION Na t u r a l flows during the p e r i o d of downstream migra-t i o n are u s u a l l y adequate, but i n some r i v e r systems, dry sec-t i o n s may develop. That is., the s u r f a c e flow may disappear i n t o h i g h l y permeable r i v e r b e d m a t e r i a l to become subsurface flow. Downstream migrants may get trapped i n p o o l s , swamps or a r t i f i -c i a l r e s e r v o i r s . To overcome these problems, a s p e c i f i e d volume of water can be held i n r e s e r v e , i f there i s c o n t r o l l e d storage a v a i l a b l e . To a i d or encourage downstream m i g r a t i o n , the r e -served water can be r e l e a s e d at the a p p r o p r i a t e time as r e l a -t i v e l y l a r g e , short p e r i o d flows. The amount to be held i n r e -serve w i l l depend on: 1. The s i z e of the r i v e r . 2. The nature of the m i g r a t i o n problem. 3. The amount of storage a v a i l a b l e . 4. The d u r a t i o n of the r e l e a s e d e x t r a flow. The s i z e of the e x t r a flow can be estimated a f t e r the r i v e r has been observed at v a r i o u s stages and the m i g r a t i o n ob-s t a c l e s have been assessed. A storage r e s e r v e to maintain the e x t r a flow f o r up:, to one or two weeks should be s u f f i c i e n t . 90 S e v e r a l short r e l e a s e s , spread over a longer p e r i o d , may be more e f f e c t i v e than one long r e l e a s e . E x t r a r e l e a s e s should not be necessary every year. 91 CHAPTER VIII INCREMENTAL ANALYSIS Much of the work to date on instream flows has been d i r e c t e d towards the det e r m i n a t i o n of "optimum flows" or "mini-mum acceptable flows", or some such f i x e d flow concept. However, where there are multi-water use c o n f l i c t s , i t i s necessary to provide the d e c i s i o n makers with, a range of p o s s i b l e instream flows and the corresponding p r o d u c t i v i t y or economic worth of the f i s h e r y . The p r i n c i p l e , of incremental a n a l y s i s i s , that f o r each incremental change i n flow, there i s a corresponding change i n p r o d u c t i v i t y , or i n the economic va l u e . Orsborn (19.76) proposes an incremental a n a l y s i s meth-od u t i l i z i n g " S e v e r i t y F a c t o r s " to give a measure of the e f f e c t of low flow r e d u c t i o n s . The s e v e r i t y f a c t o r may i n c l u d e a v a r i -able number of terms. The f o l l o w i n g four term formula w i l l be di s c u s s e d : Ql VLF1 W2/D2 W2/A2 Q2 X VLF2 X Wl/Dl X Wl/Al where SF = S e v e r i t y Factor Ql = r e f e r e n c e flow (J7 day low flow, 2 year r e c u r r e n c e i n t e r v a l ) Q2 = a flow l e s s than Q l , to be evaluated VLF1 = volume under 7-day low flow recurrence. I n t e r v a l graph between 2 and 20. years, f o r n a t u r a l c o n d i t i o n s . 92 VLF2 = VLF1 minus e f f e c t of low flow r e d u c t i o n AQ = Qi - Q 2 Wl, D l , A l = Water s u r f a c e width., average depth, cross s e c t i o n a l water area, at flow Ql W2, D2, A2 = as above, f o r Q2 The f i r s t term i s merely a r a t i o g r e a t e r than 1.0 ( a l l terms are normally greater than 1) to account f o r the gen-e r a l e f f e c t of the flow r e d u c t i o n , AQ = Qi - Q2 • The second term allows f o r the long term e f f e c t of a r e d u c t i o n i n flow due to a constant d i v e r s i o n , AQ. That i s , a r e d u c t i o n of AQ i n th.e 20 year low flow would be more severe than the same r e d u c t i o n i n the 2 year low flow. The t h i r d term i s a measure of the e f f e c t of reduced flow on the instream h a b i t a t . As flow decreases the width to depth r a t i o i n c r e a s e s . The f o u r t h term r e p r e s e n t s the temperature e f f e c t . As flow decreases the cross s e c t i o n a l water area w i l l normally decrease at a f a s t e r r a t e than w i l l the s u r f a c e width. The r a t i o W2/A2 w i l l be greater than the r a t i o Wl/Al. This i m p l i e s that i f heat energy i s e n t e r i n g the water at the s u r f a c e the water tem-perature w i l l r i s e f a s t e r at the lower flow. The s e v e r i t y f a c t o r can be obtained e i t h e r by m u l t i -p l y i n g the f a c t o r s , as. shown, In the above formula or by adding 93 them. The values obtained f o r the s e v e r i t y f a c t o r depend.; on the shape of the 7-day recurrence i n t e r v a l curve and the cross s e c t i o n a l shape of the channel. i n c r e a s i n g i n value with d e c r e a s i n g flow l e v e l s , and hence use-f u l f o r incremental a n a l y s i s — i t does not d i r e c t l y r e l a t e to h a b i t a t value or f i s h e r i e s p r o d u c t i v i t y , f o r the f o l l o w i n g reasons: 1. There i s no p r o v i s i o n f o r i n c l u d i n g r e s u l t s of b i o l o g i c a l o b s e r v a t i o n s . 2. The terms i n the SF equation w i l l not have equal weight r e l a t i v e to f i s h e r i e s product i v 1 1 y. Mllh.ous and Bov.ee (1977) have proposed a " H a b i t a t Although the s e v e r i t y f a c t o r i s q u a n t i f i a b l e — Worth Model I I formulated as fo Hows : HW I 1 = 1 A. (FD l l l l . x FV. x FS. x FT.) where A . Is the h o r i z o n t a l area of a stream I segment (.Figure. 28). i s the r e l a t i v e , worth of the h a b i t a t as r e l a t e d to the p e r f e c t depth. The p e r f e c t depth has a value of 1.00. FD . w i l l then be g e n e r a l l y l e s s than 1.00. 94 FIGURE 28 (a) DEFINITION DIAGRAM OF A STREAM SEGMENT VELOCITY (ft/sec) DEPTH (ft) (b) SAMPLE ELECTIVITY CURVES 95 The remaining terms apply s i m i l a r l y to v e l o c i t y , s u b s t r a t e , and temperature. The r e l a t i v e h a b i t a t worth f o r each term i s obtained from e l e c t i v i t y curves (Figure 28) f o r the species being s t u d i e d . At the present time they do not have e l e c t i v i t y curves f o r sub-s t r a t e and temperature so they use only the v e l o c i t y and depth terms. The h a b i t a t worth of each, stream element i s obtained by measuring or c a l c u l a t i n g the mean depth and mean v e l o c i t y , and the area A. f o r each element. The e l e c t i v i t y curves are entered l to get the e l e c t i v e p r o b a b i l i t i e s f o r v e l o c i t y and depth f o r use i n the h a b i t a t worth equation. The h a b i t a t worth can be c a l c u l a t e d f o r each stream flow being analyzed, whether i t Is a present flow, a proposed flow or a flow with a p a r t i c u l a r recurrence I n t e r v a l . Monthly, 7 day, or d a l l y flows can al s o be compared. The authors make the assumption that the p r o d u c t i v i t y i n a given stream (as mea-sured by the standing crop) i s p r o p o r t i o n a l to the h a b i t a t worth. They also, assume that the u l t i m a t e p r o d u c t i v i t y of a stream depends on the n u t r i e n t s i n the watershed and the chemical con-s t i t u a n t s i n the stream. Wcsche (19 7 6) has: proposed a cover r a t i n g formula*" f o r t r o u t : 96 C R = \ ™ ( p F ) + A (pp ) b AD where: CR = cover r a t i n g L^ ., = l e n g t h of acceptable bank cover L = l e n g t h of study s i t e A = area of study s i t e having boulders >3" dlam., and water depth. >0.5 f o o t . A^^ = area of study s i t e at average d a i l y flow. PF = p r e f e r e n c e f a c t o r f o r instream boulder a cover. PF^ = preference f a c t o r f o r bank cover. Acceptable bank cover must have a width of at l e a s t 0.3 f o o t and a water depth of at l e a s t 0.5 f o o t . Wesche r e p o r t s good c o r r e l a t i o n between standing crop and cover r a t i n g . He a l s o provides graphs of CR versus flow, suggesting they could be used i n incremental a n a l y s i s . The method I propose f o r incremental a n a l y s i s i s s i m i l a r to the above methods i n that values f o r s e v e r a l f a c t o r s are determined s e p a r a t e l y and then combined to o b t a i n a f i n a l h a b i t a t value or f i s h e r i e s p r o d u c t i v i t y r a t i n g . However, the method i s much, more f l e x i b l e i n that i t can i n c o r p o r a t e the sub-j e c t i v e , e v a l u a t i o n of experts: as w e l l as v a r i o u s q u a n t i t a t i v e techniques-. The way this: i s done i s by the use of " u t i l i t y curves". A u t i l i t y curve, i s a graph r e l a t i n g a q u a l i t a t i v e 97 e v a l u a t i o n to some q u a n t i t a t i v e v a r i a b l e . For example, the v e r t i c a l a x i s of F i g u r e 15 r e p r e s e n t s not only the spawnable area, but a l s o the value to the f i s h e r y , or the p o t e n t i a l pro-d u c t i v i t y . I f i t had been impossible to measure the spawnable area (as was done f o r the c o n s t r u c t i o n of F i g u r e 15), i t would have been p o s s i b l e f o r an experienced b i o l o g i s t , or engineer — b i o l o g i s t team, to prepare a s i m i l a r graph using judgement and experience, and having the flow, Q, as the only q u a n t i t a t i v e data. The v e r t i c a l a x i s would represent the " u t l i l i t y " , or b i o l o g i s t ' s e v a l u a t i o n . The peak of the curve would have the maximum v a l u e . The c o n s t r u c t i o n of such, a curve i s not as d i f f i c u l t as one may th i n k . I f the b i o l o g i s t observed spawning a c t i v i t y f o r a range of flows (which he knows at any time by reading a gage) he would be able to r a t e each flow l e v e l f o r spawning p r e f e r e n c e , or e f -f e c t i v e n e s s , by the behavior .of the f i s h and h i s experience. Each flow l e v e l would be r a t e d , say between zero and one, and the r a t i n g values could then be p l o t t e d a g a i n s t flow. There are unique advantages i n being able to develop a g r a p h i c a l r e l a t i o n s h i p , e i t h e r by d e t a i l e d f i e l d work or by q u a l i t a t i v e assessment: 1. The. q u a l i t a t i v e knowledge of experts or those with, wide p r a c t i c a l experience can be put on paper. 2. I f f i e l d work i s not p o s s i b l e or p r a c t i c a l a curve can s t i l l be. drawn. 98 3. The curve drawn q u a l i t a t i v e l y can be checked l a t e r by f i e l d work. 4. The curve can be drawn using p a r t l y measured data and p a r t l y q u a l i t a t i v e knowledge. 5. The curve can be. a consensus of o p i n i o n of s e v e r a l e x p e r t s . 6. A feed back process can be used. For example: a b i o l o g i s t may draw a curve q u a l i t a t i v e l y ; some c r i t i c a l f i e l d mea-surements can be made and the f i r s t curve improved; the b i o l o g i s t w i l l l e a r n from t h i s and r e v i s e h i s q u a l i t a t i v e t h i n k i n g ; the process can be repeated. 7. Knowledge gained on one system can be used on another. That i s , the f i r s t q u a l -i t a t i v e curve d e s c r i b e d i n 6 could be based on knowledge of a s i m i l a r system. The q u a l i t a t i v e assessment i s kept w i t h i n bounds by having i t expressed g r a p h i c a l l y and t e s t e d and compared with a v a i l a b l e measure.d data. A p p l i c a t i o n of the technique to the r e a r i n g phase follows-. A s e r i e s of u t i l i t y curves f o r r e a r i n g a n a l y s i s i s shown i n Fig u r e 29. 99 REARING Rearing h a b i t a t c h a r a c t e r i s t i c s a f f e c t e d by flow changes are: 1. Benthic p r o d u c t i v i t y 2 . D e p t h / v e l o c i t y matrix 3. Bank cover 4. Instream coy e.r 5. P o o l / r i f f l e , r a t i o s 6 . Temperature Stream c h a r a c t e r i s t i c s which a f f e c t r e a r i n g c o n d i -t i o n s But which, are independent of flow changes are: 1. Shade from t r e e s along the Banks 2. O r i e n t a t i o n of the stream ( d i r e c t i o n of flow) 3. Substrate. The u t i l i t y , or e f f e c t i v e n e s s , of each flow depen-dent c h a r a c t e r i s t i c can Be represented g r a p h i c a l l y . For example, Bank cover (Figure 29a) i s not g e n e r a l l y e f f e c t i v e u n t i l the flow l e v e l i s up to or beyond the toe f u l l stage. As the flow l e v e l approaches bank f u l l the value of the bank cover i n c r e a s e s to a maximum. The type of curve shown i n F i g u r e 29a could be d e v e l -oped By c a r e f u l l y measuring the amount of bank cover at s e v e r a l flow lervels. using We.sche.'s te.chni.que, modified to s u i t j u v e n i l e salmon Gas h i s work a p p l i e s p a r t i c u l a r l y : to t r o u t ) . I t i s pre-f e r a b l e to assess Bank cover and instream cover s e p a r a t e l y Be-cause each, salmon s p e c i e s has d i f f e r e n t p r e f e r e n c e s . Varying 100 FIGURE 29 UTILITY CURVES FOR ANALYSIS OF REARING HABITAT (a) BANK COVER (b) DEPTH (e) WATER TEMPERATURE (f) FINAL UTILITY CURVE I i i i 0- FEET 20 22 WATER WIDTH 0 20 22 0 CFS 30 40 FLOW 0 30 40 101 types of h a b i t a t or v a r y i n g c o n d i t i o n s may al s o a f f e c t p r e f e r -ences. I f data or time i s l i m i t e d , or measurement of cover very d i f f i c u l t or u n c e r t a i n , the f i e l d b i o l o g i s t can, a l t e r n a t i v e l y , develop a u t i l i t y curve using h i s knowledge and judgement. In p r a c t i c e , a combination of measurement and judgement i s employed to develop the best curve. Figure 29 shows example curves f o r f i v e of the c h a r a c t e r i s t i c s l i s t e d . Each curve can be developed In a s i m i l a r manner except the. temperature curve. Heat transfer, per u n i t l e n g t h of stream i s propor-t i o n a l to the width., W. The temperature r i s e i n the water w i l l be i n v e r s e l y p r o p o r t i o n a l to the ra t e of flow, Q. So the r a t i o / i s a.measure of the temperature r i s e e f f e c t and can be c a l c u -l a t e d and p l o t t e d d i r e c t l y . Of course, t h i s i s assuming c e r t a i n c o n d i t i o n s of low flow i n the heat of the summer. I f .tempera-ture i s thought to be a major problem, temperature r e c o r d e r s should be i n s t a l l e d to o b t a i n d i r e c t q u a n t i t a t i v e data. I n t e r -p r e t a t i o n of temperature data i s very d i f f i c u l t so the b i o l o g i s t may need to study j u v e n i l e behaviour under s t r e s s f u l temperature c o n d i t i o n s . C o n s i d e r a b l e judgement may be r e q u i r e d i n drawing the u t i l i t y curve f o r temperature and a s s e s s i n g the temperature e f f e c t when developing the f i n a l u t i l i t y curve. The depth, and v e l o c i t y curves can be developed by tak i n g many d e t a i l e d meas.ur eme.nts and a p p l y i n g v e l o c i t y depth, c r i t e r i a . A great deal of c a r e f u l work i s necessary and, because of the complexity of the v e l o c i t y depth, matrix i n the r e a r i n g 102 h a b i t a t , the r e s u l t s may not be worth i t . I b e l i e v e as good, or b e t t e r , r e s u l t s can be obtained by t a k i n g l i m i t e d v e l o c i t y depth measurements (perhaps at a r e f e r e n c e t r a n s e c t ) and observing the instream c o n d i t i o n s and behaviour p a t t e r n s of the j u v e n i l e s . The b i o l o g i c a l assessment together with the v e l o c i t y depth data can then be used to prepare the u t i l i t y curves. The stream h a b i t a t f a c t o r s do not have equal weight i n r e a r i n g p r o d u c t i v i t y . For example, bank cover w i l l have llt.t.Ie or no e f f e c t at very low flows. In f a c t , i t may be zero f o r a wide range of low flows, but i f other f a c t o r s are f a v o u r a b l e , p r o d u c t i v i t y may s t i l l be f a i r l y high. As the flow l e v e l nears bank f u l l the p r o d u c t i v i t y may depend very h e a v i l y on bank cover because depths and v e l o c i t i e s i n the stream may be too high to permit r e a r i n g anywhere except i n p r o t e c t e d bank area. In an area of heavy p r e d a t i o n bank cover may be more important. As each f a c t o r must be judged f o r i t s e f f e c t , i t i s necessary f o r the b i o l o g i s t to develop an o v e r a l l u t i l i t y curve. He w i l l have to consider a l l the i n d i v i d u a l curves and weigh t h e i r r e l a t i v e e f f e c t s . This would be done f o r s e v e r a l l e v e l s of flow ( s t a g e s ) . The f i n a l u t i l i t y curve w i l l r e present the expected p r o d u c t i v i t y over the f u l l range of flow l e v e l s . The advantage of t h i s method i s that i t takes i n t o account the b i o l o g i s t ' s knowledge and experience which., o f t e n , cannot be r e a d i l y quantified.. I t can be r e f i n e d to any degree d e s i r e d by i n c l u d i n g more, measured data or more f a c t o r s . 103 U t i l i t y curves could be prepared by s e v e r a l experts and the r e -s u l t s pooled f o r a f i n a l composite curve. I t i s a method which can be used even though there i s very l i t t l e data. The f i e l d measurements can be simply made by the b i o l o g i s t . Study s i t e s should be p o s i t i o n e d where stream char-a c t e r i s t i c s are t y p i c a l and where depths and v e l o c i t i e s can be r e a d i l y measured. A r e f e r e n c e t r a n s e c t i s needed at each s i t e where water width, stage, depths and v e l o c i t i e s are measured during each f i e l d t r i p . The c o n d i t i o n s at the r e f e r e n c e t r a n s e c t are not, however., intended to re p r e s e n t the average c o n d i t i o n s f o r the study s i t e . I w i l l e x p l a i n t h i s by an example i n v o l v i n g benthic p r o d u c t i o n : Th.e b i o l o g i s t w i l l look at benthic produc-t i o n f o r the whole study s i t e . Benthic p r o d u c t i o n w i l l occur i n r i f f l e areas which, may not be near the r e f e r e n c e t r a n s e c t . How-ever, each time he assesses the benthic p r o d u c t i o n he must read the stage l e v e l at the r e f e r e n c e t r a n s e c t . The bent h i c produc-t i o n can then be p l o t t e d as a f u n c t i o n of the stage at the r e f -erence t r a n s e c t . I f he wishes to examine the e f f e c t s of v e l o c i t y and depth he can take as many depth and v e l o c i t y measurements as he l i k e s anywhere i n the study s i t e ( p r e f e r a b l y In some o r d e r l y manner, as at a u x i l i a r y t r a n s e c t s ) but he must read the stage at the r e f e r e n c e t r a n s e c t . I t w i l l be necessary, anyway, to take a s e r i e s of v e l o c i t y depth measurements at the r e f e r e n c e t r a n s e c t i n order to develop a stage d i s c h a r g e curve f o r the range of flows being s t u d i e d . The v e l o c i t y depth measurements obtained f o r t h i s purpose should, i n many cases:, be adequate i n themselves f o r the a n a l y s i s of the study s i t e . 104 SPAWNING Incremental values f o r spawning h a b i t a t can be obtained d i r e c t l y from the Spawning H a b i t a t versus Flow curve (Figure 15). These curves w i l l be somewhat d i f f e r e n t f o r each study s i t e . The u t i l i t y curve i s prepared by c o n s i d e r i n g each Spawning H a b i t a t curve and weighting i t i n p r o p o r t i o n to the number of spawners represented by each study s i t e . Other aspects of spawning success can be incorporated, i n t o the u t i l i t y curve. For example, If i n c u b a t i o n flows are known to have a c e r t a i n minimum v a l u e , then higher u t i l i t y value w i l l have to be placed on those spawning flows equal to or s l i g h t l y g r e a t e r than t h i s minimum i n c u b a t i o n v a l u e . INCUBATION Incremental a n a l y s i s cannot be r e a d i l y a p p l i e d to the i n c u b a t i o n p e r i o d . I f the i n c u b a t i o n flow l e v e l i s not l e s s than 3 or 4 inches below the spawning flow l e v e l there should be no l o s s . I f the water l e v e l drops 6 Inches or more, eggs may be destroyed because of d e s i c c a t i o n , but there i s no way of knowing to what degree without very d i f f i c u l t and ext e n s i v e m o n i t o r i n g . F o r t u n a t e l y , low flows during the i n c u b a t i o n p e r i o d are not nor-mally as frequent or s e r i o u s as at other times. I f there i s storage In the system water can u s u a l l y be r e l e a s e d to augment any over winter low flows which may occur, because winter demand by l i c e n s e d users is- u s u a l l y l i g h t or n o n - e x i s t e n t . 105 . The g r e a t e s t egg l o s s i s probably caused by high f l o o d flows ( F i g u r e 25). Once g r a v e l scour becomes s i g n i f i c a n t , eggs w i l l be destroyed. The higher the flow, and the more prolonged, the more that w i l l be l o s t . Again, i t i s p r a c t i c a l l y i m p o s s i b l e to know what p r o p o r t i o n of the eggs w i l l be destroyed. I f f l o o d flows could be reduced or routed away from the spawning beds a very s i g n i f i c a n t improvement i n i n c u b a t i o n success could be expected. UPSTREAM AND DOWNSTREAM MIGRATION D i f f e r e n t flow l e v e l s have some e f f e c t on these phases of the l i f e c y c l e but not i n a way which can be r e a d i l y used i n incremental a n a l y s i s . In some cases incremental values may be a p p l i e d to upstream m i g r a t i o n . For example, a c e r t a i n i n c r e a s e i n flow could allow f i s h i n t o an e x t r a spawning area not a c c e s s i b l e at lower flows. 106 CHAPTER IX PROCEDURE FOR ESTABLISHING "FISHERIES RESOURCE MAINTENANCE FLOWS" An o u t l i n e of the procedure which I recommend f o r e s t a b l i s h i n g F i s h e r i e s Resource Maintenance Flows i s shown i n Fig u r e 30. The whole, watershed must be considered i f the f i n a l r e s u l t s are to have v a l i d i t y . Each watershed has i t s . own unique c h a r a c t e r i s t i c s and c o n s t r a i n t s . One of the primary c o n s t r a i n t s w i l l be the amount of water a l r e a d y l i c e n s e d f o r use. A p h y s i c a l c o n s t r a i n t may be an e x i s t i n g dam. Once a l l e x i s t i n g i n f o r m a t i o n has been gathered an " I n v e s t i g a t i o n memorandum" (Orsborn 1976) should be prepared, to i n c l u d e : 1. L i s t i n g of a l l a v a i l a b l e data such as r e p o r t s , maps, correspondence review. 2. S p e c i f i c problems to be sol v e d . 3. O u t l i n e of proposed study program. 4. Timing, manpower, c o s t s . 5. L i s t of water l i c e n s e s . Water l e v e l and temperature r e c o r d e r s should be In-s t a l l e d , i f they are needed, as soon as p o s s i b l e a f t e r a d e c i s i o n has been made to do a study. P r e l i m i n a r y f i e l d i n v e s t i g a t i o n should be s t a r t e d . I t may be at t h i s stage -that suitable, s i t e s f o r i n s t r u m e n t a t i o n can Be s e l e c t e d and instruments i n s t a l l e d . Study s i t e s f o r spawning and r e a r i n g should Be s e l e c t e d , and gages I n s t a l l e d and 107 FIGURE 30 PROCEDURE OUTLINE FOR ESTABLISHING FISHERIES RESOURCE MAINTENANCE FLOWS R e c o g n i t i o n of a low f l o w problem D e c i s i o n to e s t a b l i s h i n s t r e a m f l o w s C o l l e c t and Review a v a i l a b l e i n f o r m a t i o n maps, cor r e s p o n d e n c e r e p o r t s , W.L. data e t c E a r l y I n s t r u m e n t a t i o n Water Recorder Thermograph Prepare an i n v e s t i g a t i o n memorandum P r e l i m , o f f i c e A n a l y s i s C o r r e l a t i o n Techniques I P r e l i m . f i e l d i n v e s t i g a -t i o n s ; determine watershed c o n s t r a i n t s and unique c o n d i t i o n s I n s t r u m e n t a t i o n Water Recorder Thermograph S e l e c t methodology and d e v e l o p study p l a n 1 U t i l i z e ~1 r e s e a r c h I c r i t e r i a & | i n f o r m a t i o n j D e t a i l e d F i e l d Work F i n a l a n a l y s i s of d a t a t a k i n g i n t o account watershed c o n s t r a i n t s and unique c o n d i t i o n s H Feedback""! to | Resear c h ' I n t e r a g e n c y r e v i e w ; n e g o t i a t i o n s w i t h o t h e r water u s e r s Recommendations f o r i n s t r e a m f l o w s M o n i t o r i n g <> P o l i c i n g 108 t r a n s e c t s marked out. A general understanding of the whole water-shed should be obtained during t h i s p r e l i m i n a r y work so that i t s s p e c i a l c h a r a c t e r i s t i c s and c o n s t r a i n t s w i l l be known. I n t e r -views with water u s e r s , r e s e r v o i r operators and others are a d v i s -a b l e . A l l the main water d i v e r s i o n s and uses should be examined and i n v e n t o r i e d . O f f i c e a n a l y s i s can be s t a r t e d at the same time as, or even b e f o r e , the i n i t i a l f i e l d work. I t may Include c o r r e l a -t i o n a n a l y s i s , hydrograph a n a l y s i s u sing e x i s t i n g r e c o r d s , and a review of a l l water l i c e n s e s . A f t e r reviewing the r e s u l t s of the p r e l i m i n a r y work a f i n a l p lan should be prepared f o r the remaining d e t a i l e d f i e l d work, and techniques s e l e c t e d to best s u i t the p a r t i c u l a r prob-lems being faced. Study s i t e s are s e l e c t e d and gages are i n s t a l -l e d , i f t h i s work has not a l r e a d y been done duri n g the p r e l i m i n a r y phase. D e t a i l e d measurements and o b s e r v a t i o n s are made f o r sev-e r a l flow l e v e l s f o r the s e v e r a l l i f e stages as d e s c r i b e d i n Chapters VII and V I I I . The d e t a i l e d f i e l d work may have to be spread over one or two years to get s u f f i c i e n t data f o r a l l the stages of the salmon's l i f e c y c l e . The next step i s the f i n a l a n a l y s i s of data. Interagency d i s c u s s i o n s and v a r i o u s n e g o t i a -t i o n s f o l l o w (although they may be s t a r t e d anytime during the p e r i o d of the s t u d y ) . The d i s c u s s i o n s and n e g o t i a t i o n s , combined with the t e c h n i c a l a n a l y s i s , w i l l l ead i n t o a f i n a l r e p o r t c o v e r i n g a set of recommendations which may i n c l u d e any of the 109 f o l l o w i n g : 1. A schedule of recommended flows. 2. Recommendations on storage developmen t. 3. Rule curve f o r r e s e r v o i r o p e r a t i o n . 4. Suggested design of d i v e r s i o n s . 5. Methods of m o n i t o r i n g . 6. Changes i n water management or r e s t r i c t i o n s i n water use. 7. P h y s i c a l changes to improve the use of the watershed, such as removal of o ld dams and other o b s t r u c t i o n s , or a r t i f i c a l c l e a n i n g of spawning beds. 110 CHAPTER X WATER MANAGEMENT F i s h e r i e s Resource Maintenance Flows are normally provided f o r i n one of the f o l l o w i n g ways: 1. Clauses i n water l i c e n s e s 2. Legal agreements 3. Informal v e r b a l or w r i t t e n agreements Recommendations f o r F i s h e r i e s Resource Maintenance Flows should be phrased In such a way that they can be r e a d i l y i n c o r p o r a t e d as clause s i n a water l i c e n c e , and e a s i l y adopted i n the f i e l d with a minimum amount of p o l i c i n g and mo n i t o r i n g . The Water Comptroller can place many types of c o n d i t i o n s on a l i c e n c e , e i t h e r by cl a u s e s i n th.e l i c e n c e or by orders accompanying the l i c e n c e . The f o l l o w i n g c l a u s e s , p r o v i d i n g f o r f i s h e r i e s flows, have been i n c o r p o r a t e d i n t o water l i c e n s e s : 1. The d i v e r s i o n of water may be r e s t r i c t e d or p r o h i b i t e d at any time by w r i t t e n order of the Engineer f o r the Water D i s t r i c t to maintain a minimum flow f o r the p r e s e r -v a t i o n of f i s h l i f e i n the stream. 2. The Comptroller may, upon s i x months n o t i c e , amend the wording of the above cl a u s e and may c a n c e l the l i c e n c e f o r any reason upon ten years notice, to the l i c e n s e e . I l l One of the more favo u r a b l e types of l i c e n s e s i s one which l i m i t s use to s p e c i f i c p e r i o d s of the year. For example, i f a l i c e n s e i s issued f o r d i v e r s i o n to storage i t can be l i m i t e d to the high flow winter p e r i o d where flows are u s u a l l y not c r i t -i c a l f o r f i s h e r i e s . I f the dates of s t a r t of d i v e r s i o n can be set to correspond with the end of the spawning p e r i o d , t h i s a l s o i s an advantage. In some cases storage, has been j o i n t l y developed f o r f i s h e r i e s and I r r i g a t i o n uses. A l e g a l agreement Is necessary to ensure f a i r o p e r a t i o n of the r e s e r v o i r and provide f o r appor-tionment of o p e r a t i n g and maintenance c o s t s . The water l i c e n s e s which are issued to both p a r t i e s by the Water Comptroller become, i n e f f e c t , part of the agreement. There are a number of i n f o r m a l or t a c i t agreements f o r r e l e a s e of water f o r f i s h e r i e s . Most of the agreements of t h i s type are with B.C. Hydro and Power A u t h o r i t y . To date there has been very l i t t l e r e g u l a r monitoring of Instream flow agreements. I t i s becoming i n c r e a s i n g l y impor-tant that t h i s be done. A b a i l i f f can be appointed by the Water Comptroller to police, streams, and perhaps t h i s needs to be done for a l l c r i t i c a l streams. A b a i l i f f would need only to concen-t r a t e on low flow probelms. which, would occur during s p e c i f i c s e a so n s . 112 Water management of instream flows should become of great e r concern. I b e l i e v e that, as part of instream water management, the f o l l o w i n g recommendations should be c o n s i d e r e d : 1. A l l p o t e n t i a l water storage s i t e s should be r e s e r v e d . 2. An e f f o r t should be made to u t i l i z e s u r p l u s winter or s p r i n g flows. T h i s i m p l i e s storage development or, p o s s i b l y , d i v e r s i o n from one t r i b u t a r y , or r i v e r system, to another. Re-du c t i o n of high, flows, e f f e c t e d i n t h i s way, could enhance the f i s h e r y by reducing g r a v e l e r o s i o n i n spawning beds. 3. A program should be developed to monitor and enforce a l l instream flow agreements. This Is probably the r e s p o n s i b i l i t y of the Water Rights Branch of the M i n i s t r y of the Environment. 4. Post development s t u d i e s should be made, a f t e r flow agreements have been In e f f e c t f o r a p e r i o d of time, to assess the e f f e c t i v e n e s s of the new flow regimes. 113 LITERATURE CITED Bagnold, R.A., "Experiments on a G r a v i t y - F r e e D i s p e r s i o n of Large S o l i d Spheres i n a Newtonian F l u i d Under Shear", Proc. Royal S a c , Ser. A, 225 (1160) , 49-63, 1954 . Bams, R.A., "Adaptations of Sockeye Salmon A s s o c i a t e d with Incu-b a t i o n In Stream G r a v e l s " , In: Symposium on Salmon and Trout i n Streams, I n s t i t u t e of F i s h e r i e s , U n i v e r s i t y of B r i t i s h . Columbia, Vancouver, B.C., 1969 . Banks, J.W., "A Review of the L i t e r a t u r e on the Upstream Migra-t i o n of Adult Salmonlds", J o u r n a l of F i s h B i o l o g y , 1969, V o l . 1 pp 85-136. B e l l , M.C., " F i s h e r i e s Handbook of Engineering Requirements and B i o l o g i c a l C r i t e r i a " , Corps of Engineers, North P a c i f i c D i v i s i o n , P o r t l a n d , Oregon, Feb. 1973. Chambers, J.S., A l l e n , G.A., and Pressey, T., "Research R e l a t i n g to Study of Spawning Grounds i n N a t u r a l Areas", Washing-ton, Department of F i s h e r i e s , Olympia, Washington, 1955. C o l l l n g s , M.R., " G e n e r a l i z a t i o n of Spawning and Rearing D i s -charges f o r Se v e r a l P a c i f i c ^ Salmon Species i n Western Washington", United States Department of the I n t e r i o r , G e o l o g i c a l Survey, Tacoma, Washington, 1974. Cooper, A.C., "The E f f e c t of Transported Stream Sediments on the S u r v i v a l of Sockeye and Pink Salmon Eggs and A l e v i n " , I n t e r n a t i o n a l P a c i f i c Salmon F i s h e r i e s Commission, New Westminster, B.C., Canada, 1965. C u l l e n , A., and Ducharme, A., "Techniques f o r Determination of Maintenance Flows f o r P r o t e c t i o n of F i s h H a b i t a t " , Department of the Environment, P.O. Box 550, H a l i f a x , Nova S c o t i a , 1976. DeBeck, H.D., "Present Use of B r i t i s h Columbia's Water", B r i t i s h Columbia Department of Lands, F o r e s t s , and Water Re-sources, V i c t o r i a , B.C., Feb. 1967. D i l l , L.M., "The Sub-gravel Behaviour of P a c i f i c Salmon Larvae", In: Symposium on Salmon and Trout i n Streams, I n s t i t u t e of F i s h e r i e s , U n i v e r s i t y of B r i t i s h . Columbia, Vancouver, B.C., 19.6 2. Freeze, R.A., and Witherspoon, P.A., " T h e o r e t i c a l A n a l y s i s of Regional Groundwater Flow", Water Resources Research, V o l . 3, 19.6 7 114 Glger, R.D., "Streamflow Requirements of Salmonids", Oregon Wild-l i f e Commission, P.O. Box 3503, P o r t l a n d Oregon, 1973. Hamilton, R., and Bue.ll, J.W., " E f f e c t s of M o d i f i e d Hydrology on Campbell River Salmonids", Environmental Canada, F i s h -e r i e s and Marine S e r v i c e , P a c i f i c Region, T e c h n i c a l Report S e r i e s PAC/T-76-20, 1976. Hooper, D.T., " E v a l u a t i o n of the E f f e c t s of Flows on Trout Stream Ecology", Department of Engi n e e r i n g Research, P a c i f i c Gas and E l e c t r i c Co., E m e r y v i l l e , C a l i f o r n i a , 1973. Hunter, J.W., "A D i s c u s s i o n of Game. F i s h i n the State of Washing-ton as Related to Water Requirements", Washington State Department of Game, Olympia, 1973. Kennedy, H.D., "Seasonal Abundance of Aquatic I n v e r t e b r a t e s and Their U t i l i z a t i o n by Hatchery Reared Rainbow Trout", Bureau of Sport F i s h e r i e s and W i l d l i f e , U.S. Department of the I n t e r i o r , T e c h n i c a l Paper No. 12, 1967. K r a j l n a , V.J., " B l o g e o c l i m a t i c Zones of B r i t i s h Columbia", a map publis h e d by the B r i t i s h Columbia E c o l o g i c a l Reserves Committee, Department of Lands, F o r e s t s , and Water Re-sources, V i c t o r i a , B r i t i s h Columbia, not dated. McKernan, D.L., Johnson, D.R., and Hodges, J . I . , "Some Fa c t o r s I n f l u e n c i n g the Trends of Salmon P o p u l a t i o n s i n Oregon", T r a n s a c t i o n s North. American W i l d l i f e C o n f e d e r a t i o n , 1950, V o l . 15, pp 437-441. Milhous, R.T., "The C a l i b r a t i o n of Equations Used to C a l c u l a t e the V e l o c i t y D i s t r i b u t i o n i n a River f o r Instream Flow A n a l y s i s " , Department of Ecology, Olympia, Washington, U.S.A., Nov . 19^ 7 7 . Milhous, R.T., and Bovee, Ken, "Instream Flow Requirements and Stream Morphology", Cooperative Instream Flow S e r v i c e Group, U.S. F i s h and W i l d l i f e S e r v i c e , F o r t C o l l i n s , Colorado, 80521, Oct. 19.77. M i l l e r , J.D., "The E f f e c t s of Minimum and Peak Cedar River Stream-flows on Fish. P r o d u c t i o n and Water Supply", Master's T h e s i s , U n i v e r s i t y of Washington, U.S.A., 19.76. Needham, P., and Usingcr, R. , " V a r i a b i l i t y i n the. Macrofauna of a S i n g l e R i f f l e i n Prosser Creek, C a l i f o r n i a , as Indir: cated by a Surber Sampler", H i l g a r d l a , C a l i f o r n i a A g r i -c u l t u r a l Experimental S t a t i o n , V o l . 24, No. 14, 1956. 115 N i c k e l s o n , T.E., "Development of Methodologies f o r E v a l u a t i n g In-stream Flow Needs f o r Salmon Rearing", In: Proceedings of the Symposium and S p e c i a l t y Conference on Instream Flow Needs, American F i s h e r i e s S o c i e t y , 5410 Grosvenor Lane, Bethesda, Maryland, U.S.A., Sept. 1976 , V o l . 2, pp 588-5 9.6. Orsborn, J.F., and Deane, D.F., " I n v e s t i g a t i o n i n t o Methods f o r Developing a P h y s i c a l A n a l y s i s f o r E v a l u a t i n g Instream Flow Needs", Department of C i v i l and Environmental E n g i -n e e r i n g , Washington State U n i v e r s i t y , Pullman,.WA 99164, Sept. 1976. Pearson, L.S., Conover, K...R. and Sams, R.E., " F a c t o r s A f f e c t i n g the N a t u r a l Rearing of J u v e n i l e Coho Salmon During the Summer Low Flow Season", Oreg on F i s f i C OTnmission, POTJ*tXa.nd.5 19.7 0. Redel, W.R., " R i p a r i a n R i g h t s " , Aim, p u b l i s h e d by A p p r a i s a l In-s t i t u t e of Canada, 93 Lombard Avenue, Winnipeg, Manitoba, Canada, F a l l 1967. Riggs, H.C., "Mean Streamflow from Discharge Measurements", I n t e r -n a t i o n a l A s s o c i a t i o n of S c i e n t i f i c Hydrology, B u l l e t i n XIV, 4:9.5-110, 19.6 9. Riggs, H.C., "Low Flow. I n v e s t i g a t i o n s " , U.S. G e o l o g i c a l Survey Techniques of Water Resources I n v e s t i g a t i o n s , Book 4, Chapter B l , 19.7 2. Shen, H.W., " S t o c h a s t i c Approaches to Water Resources", H.W. Shen, P.O. Box 606, F o r t C o l l i n s , Colorado, U.S.A. 80521, 1976. Smith, A.K., " F i s h and W i l d l i f e Resources of the A m a t i l l a Basin, Oregon, and T h e i r Water Requirements", Oregon State Game Commission, 1973. St a l n a k e r , C.B., and A r n e t t e , J.L., "Methodologies f o r the Deter-mination of Stream Resource Flow Requirements: An Assess-ment", Utah. State U n i v e r s i t y , Logan, Utah, 1976 . Stober, Q.J. , and G r a y b i l l , J ..P. , " E f f e c t s of Discharge i n the Cedar River on Sockeye Salmon Spawning Area", U n i v e r s i t y of Washington Research. I n s t i t u t e , S e a t t l e , Washington, 19.7 4. Surber, E.W., "Bottom Fauna and Temperature C o n d i t i o n s i n Rel a -t i o n to Trout Management i n St. Mary's R i v e r , Augusta County, V i r g i n i a " , Va. J S c i . 2 : 19.0-202 . 19.51 . 116 Tautz, A.F., and Groot, C., "Spawning Behaviour of Chum Salmon (Oncorhynchus keta) and Rainbow Trout (Salmo g a i r d n e r i ) " , J o u r n a l F i s h e r i e s Research Board, Canada, V o l . 32, No. 5, 1975, pp 633-642. Tennant, D.L., "Instream. Flow Regimens, f o r F i s h , W i l d l i f e , Re-c r e a t i o n and Related Environmental Resources", F i s h e r i e s , V o l . 1 No. 4, Aug. 19.7 6. Thompson, K.E., "Determining Streamflows f o r F i s h L i f e " , In: Proceedings Instream.Flow Requirement Workshop, P a c i f i c Northwest River Basins Commission, P o r t l a n d , Oregon, 1972 pp 31-50. Waters, B.F., "A Methodology f o r E v a l u a t i n g the E f f e c t s of D i f -f e r e n t Streamflows on Salmonid H a b i t a t " , In: Proceedings of the Symposium and S p e c i a l t y Conference on Instream Flow Needs, American F i s h e r i e s S o c i e t y , 5410 Grosvenor Lane, Bethesda, Maryland, U.S.A., Sept. 1976, V o l . 2, pp 254-266. Water Survey of Canada, Inland Waters D i r e c t o r a t e , P a c i f i c Re-gion, Department of Environment, "Low Flows In B r i t i s h Columbia", Jan. 19.7 4. Wesche, T.A., "Development and A p p l i c a t i o n of a Trout Cover Rat-ing System f o r Instream Flow Needs Determinations", In: Proceedings of the Symposium and S p e c i a l t y Conference on Instream Flow Needs, American F i s h e r i e s S o c i e t y , 5410 Grosvenor Lane, Bethesda, Maryland, U.S.A. Sept. 1976, V o l . 2, pp 224-234. Yaug, C.T., "Formation of R i f f l e s and Po o l s " , Water Resources Research, V o l . 7, No. 6, Dec. 1971, pp 1567-1574. 117 GLOSSARY ALEVIN — The l i f e stage of salmon between hatching and the f r e e swimming f r y stage. A l e v i n s g e n e r a l l y remain w i t h i n the g r a v e l of the stream bed. BENTHIC — Bottom d w e l l i n g . FISHERIES RESOURCE MAINTENANCE FLOWS — E s s e n t i a l l y synonomous with stream Resource Maintenance Flows, but p e r t a i n i n g p a r t i c u -l a r l y to the f i s h e r y . FORK LENGTH — The d i s t a n c e from the t i p of the nose to the fo r k (vee) of the t a i l of a f i s h . METHODOLOGY — A body of techniques used f o r a systematic i n q u i r y . MINIMUM FLOW — May mean the lowest d a i l y flow recorded each year at a s t a t i o n , or the lowest d a i l y flow f o r the t o t a l p e r i o d of rec o r d . PRODUCTIVITY — The r a t e of i n c r e a s e i n the biomass (or i n the standing c r o p ) . REDD — The place i n the streambed where the female salmon der p o s i t s her eggs. STANDING CROP — The biomass (jln t h i s case, f i s h and suppo r t i n g food chain) w i t h i n a s p e c i f i e d area of a stream at a po i n t i n time. STREAM RESOURCE MAINTENANCE FLOWS — A term developed i n Idaho by Fed e r a l and State agencies to mean "a range of flows w i t h i n which f i s h , w i l d l i f e and other a q u a t i c organisms are maintained, p r o t e c t e d and r e s t o r e d " . UTILITY CURVE — A graph, q u a n t i t a t i v e v a r i a b l e . r e l a t i n g a q u a l i t a t i v e e v a l u a t i o n to a 118 APPENDIX A COMPUTER PROGRAM "STREAM FLOW" "Stream Flow" i s a computer program which c a l c u l a t e s the area of the streambed over which water v e l o c i t i e s and depths s a t i s f y the c r i t e r i a f o r spawning salmon, given e i t h e r the flow i n c . f . s . or the e l e v a t i o n of the water s u r f a c e . The program i s data dependent; that i s , i t w i l l operate on a minimum amount of input , But the output w i l l improve with the amount and accuracy of input data. Input c o n s i s t s of: 1. Topographical Information f o r one or more t r a n s e c t s ( c r o s s - s e c t i o n s ) . . 2. V e l o c i t y and depth c r i t e r i a f o r the species Being s t u d i e d . 3. One or more flow v a l u e s , with corresponding eleva-:' tlons-, f o r at l e a s t one t r a n s e c t . 4. A r a t i n g of the s u b s t r a t e at each measured p o i n t along the t r a n s e c t . .5. The s p e c i f i e d flows (or water l e v e l s ) to be analyzed. Output (Tables A l and ALL) c o n s i s t s of: 1. Spawning area t r i b u t a r y to each t r a n s e c t f o r each s p e c i f i e d flow. 2. Parametric data ( c r o s s - s e c t i o n a l water area, surface, wid th, wetted perimeter, e t c . ) f o r each, t r a n s e c t f o r each s p e c i f i e d flow. 119 3. V e l o c i t i e s and depths at a l l p o i n t s on the t r a n s e c t , f o r each, s p e c i f i e d flow. FIELD WORK Transects are l a i d out p e r p e n d i c u l a r to the flow be-tween permanent r e f e r e n c e markers. I suggest four t r a n s e c t s be grouped together 20 to 50 f e e t apart to form a study s i t e 60 to 150 f e e t long (Figure 11). The p r o f i l e of each, t r a n s e c t i s surveyed using s t a n -dard t o p o g r a p h i c a l survey procedures. Ground e l e v a t i o n s are taken to th.e nearest 0.1 f o o t and water surface e l e v a t i o n s to the nearest 0.01 f o o t . The p r o f i l e should be continued up each bank a l i t t l e beyond the "bank f u l l " l e v e l . Although the computer program t r e a t s each t r a n s e c t independently, and does not r e q u i r e s t r i c t adherence to the f o l -lowing r u l e s ; i t i s recommended that they be followed to s i m p l i f y subsequent i n t e r p r e t a t i o n , a n a l y s i s , and p l o t t i n g : 1. A l l e l e v a t i o n s f o r a p a r t i c u l a r study s i t e should be r e f e r r e d to one datum. 2. A l l chainages to p o i n t s along t r a n s e c t s should be r e f e r r e d to e i t h e r the r i g h t bank or the l e f t b. ank. 3. Thalweg d i s t a n c e s between t r a n s e c t s should be mea snared . 120 The flow should be metered at l e a s t once at each t r a n s e c t . I recommend metering at three or more flow l e v e l s at each t r a n s e c t so as to provide b e t t e r input data f o r the com-puter. The v e l o c i t y and depth, i s measured at p o i n t s 1 to 10 f e e t apart along the t r a n s e c t (Figure 11). The v e l o c i t y i s measured 0.6 of the depth below the s u r f a c e . This r e p r e s e n t s the average v e l o c i t y . The "nose, v e l o c i t y " , assumed to be 0.4 f o o t o f f the bottom, can al s o be measured. PROGRAM DESCRIPTION The program uses the f o l l o w i n g form of the Manning equa t i o n : 5 /1 ' „A ' , „ 1.486 S 2 Q = C 0 , „ where C = p2/3 n The values of C are c a l c u l a t e d f o r each metered flow and stored as a 11C graph" f o r each t r a n s e c t . I f three or more flows have been metered, the "C graph" w i l l provide accuracy comparable to a stage discharge curve. F i g u r e s A l and A2 are the flow c h a r t s f o r the main program and subroutine PRAM. The subroutine c a l c u l a t e s the f o l l o w i n g geometric parameters of a t r a n s e c t given the water sur-face e l e v a t i o n : 1. Cross s e c t i o n a l water area. 2. Width of water s u r f a c e . 121 3 . Wetted perimeter. A . Maximum depth. 5 . Average Depth. 6. Chainage to edge of water. The subroutine w i l l take care of d i v i d e d flows or m u l t i p l e channels. Punch cards r e q u i r e d f o r the data deck are d e s c r i b e d i n Tabel A ITT, and an abr e v l a t: ed l i s t of symbols Is provided i n Table AIV . A l i s t i n g of the program i s not provided as i t i s lengthy, but a sample of the output f o r one t r a n s e c t ( s e c t i o n ) and a summary f o r one flow are in c l u d e d as Tables A l and A l l . The program In I t s present form d i s t r i b u t e s v e l o c i t y across the t r a n s e c t i n p r o p o r t i o n to the water depth; that i s , the v e l o c i t y p r o f i l e i s a. .mlr-rror image of the depth p r o f i l e , ad-j u s t e d f o r s c a l e . A l t e r n a t e models of v e l o c i t y d i s t r i b u t i o n are disc u s s e d i n Chapter IV. Another p o s s i b i l i t y with t h i s computer program i s to use the v e l o c i t y input data as a model. Each set of measured t r a n s e c t v e l o c i t y data could be stored as a model of the v e l o c i t y p r o f i l e . For i n t e r p o l a t e d or e x t r a p o l a t e d flows, the most a p p r o p r i a t e stored p r o f i l e i s chosen a s a . p a t t e r n f o r the v e l o c i t y d i s t r i b u t i o n . e i t h e r : 1, s u i t a b l e g r a v e l present; or 0, no s u i t a b l e g r a v e l present; but a r a t i n g of- 0 to 10 could e a s i l y be i n c o r p o r a t e d i n the f u t u r e . Input data f o r s u b s t r a t e Is p r e s e n t l y r e s t r i c t e d to 122 The program was o r i g i n a l l y set up on the assumption that each t r a n s e c t would rep r e s e n t the stream h a l f way to a d j a -cent t r a n s e c t s ; But now, I recommend that each t r a n s e c t r e p r e s e n t a s t r i p only one f o o t wide ( c o n t r I B u t a r y l e n g t h = 1.0) although i f s u B s trate Is to Be assessed i t may Be B e t t e r to consider a wider s t r i p , perhaps one meter wide. The program gives equal weight to any depth v e l o c i t y combination w i t h i n the species c r i t e r i a ; f o r example, the combi-n a t i o n of optimum depth, and optimum v e l o c i t y w i l l have the same weight as the combination of the minimum depth and minimum v e l o c -i t y . Weighted values w i l l Be introduced i n a r e v i s i o n of the program. 123 PROGRAM "STREAMFLOW" SAMPLE OUTPUT FOR A SECTION AT A SPECIFIED FLOW TABLE Al SECTION: 8 RUN NO. 7 DISCHARGE Q=550.0 CFS COEF. C = 1.02 POINT CHAINAGE DEPTH VEL. SPAWN. AREA 1 8.0 .0 .0 .0 2 10.0 .0 .0 .0 3 15.0 3.0 2.1 6.5 4 23.0 3.6 2.5 9.0 5 33.0 3.4 2.4. 10.0 6 43.0 3.1 2.2 10.0 7 53.0 2.5 1.8 10.0 8 63.0 2.4 1.7 10.0 9 73.0 2.4 1.7 10.0 10 83.0 2.5 1.8 10.0 11 93.0 2.2 1.5 10.0 12 103.0 2.3 1.6 10.0 13 113.0 2.1 1.5 10.0 14 123.0 2.0 1.4 .0 15 125.0 .0 .0 .0 16 126.0 .Q .0 .0 GRAVEL(0=NO.1=YES) 0 0 1 1 1 1 1 1 1 1 1 1 1 Q 0 Q PROGRAM "STREAMFLOW" SAMPLE OUTPUT OF A SUMMARY TABLE SUMMARY FOR RUN NO. 7 AT DISCHARGE Q = 550.0 CFS. SECTION SURFACE SURF. DIST. TO AREA MAX. WETTED SURFACE SPAWNING WIDTH ELEV. WATER EDGE DEPTH PERIMETER AREA AREA 5 124.2 97.3 8.1 200.2 2.7 .125.3 124.2 90.0 6 124.9 97.8 4.8 184,4 2.5 125.9 124.9 88.5 7 119.. 4 98.0 2.0. 248.4 2.5 121.1 119.4 107.5 8 115.0 98.0 1Q.0 292.9. 3.6 116.7 115.0 105.5 125 TABLE AIII DATA CARDS FOR COMPUTER PROGRAM "STREAM FLOW" CARDS INFORMATION FORMAT General Cards 1st card 2nd card 3rd card one or more cards "Name of river" "Species of salmon" NR, NS, SAR, VI, V2, DS1, DS2, VNOSE QR(1), ELEV(l): OR (2), ELEV(2): etc. 20A4 20A4 315,6F10.3 8F10.1 Following set of cards required for each section one card "Number of section" one card ' NP, TM, TC, NCD, DIST one or more cards one or more cards CH(1), ELC I ) , SG(1); etc. QC(.l), ELEVC(l), CC(1): etc. 4A4 415,F10.1 5(2F7.1,12) 4(2F8.1,F4.2) 126 TABLE AIV PARTIAL LIST OF SYMBOLS USED IN COMPUTER PROGRAM "STREAMFLOW" A Area of cross s e c t i o n B Width of water su r f a c e C Flow c o e f f i c i e n t CC(T). Flow c o e f f i c i e n t input data CH(I) Chainage to each, p o i n t i n c r o s s - s e c t i o n CHB Chainage to waters edge D(I) Depth of water at each p o i n t i n cross s e c t i o n DMAX Maximum depth In cross s e c t i o n DAV Average depth of water i n cross s e c t i o n DS1 Minimum spawning depth. DS2 Maximum .spawning depth DIST Length of r i v e r to which cross s e c t i o n a p p l i e s ( c o n t r i b u t a r y length) EL(I) E l e v a t i o n of ground at each p o i n t i n cr o s s s e c t i o n ELEV(I) E l e v a t i o n of water su r f a c e f o r each run ELEVC(I) E l e v a t i o n of water su r f a c e corresponding to CC(.I) NP Number of p o i n t s i n cross s e c t i o n NS Number of s e c t i o n s NR Number of runs NCD Number of input data groups f o r C de t e r m i n a t i o n P Wetted perimeter Q Discharge QC(I) Discharges corresponding to CC(I) QR(I) Discharges f o r runs SAR T r i g g e r i f spawning areas r e q u i r e d SG(I) Spawning g r a v e l i n d i c a t o r ( f i e l d o b servation) TC T r i g g e r i f previous C graph to be used TM T r i g g e r i f metering notes input V E L C I ) V e l o c i t y at points, i n cross s e c t i o n VI Minimum spawning v e l o c i t y V2 ^Maximum spawning v e l o c i t y VNOSE Factor by which average v e l o c i t y is: m u l t i p l i e d to ob t a i n nose v e l o c i t y "STREAM FLOW" COMPUTER PROGRAM FLOW CHART Start T I n i t i a l i z e T READ General Data: Name of river Species of f i s h Number of runs Number of sections Preferred velocity and depth range Known flow data WRITE river name, f i s h species and other selected input data READ Section Data: Number of surveyed points, Contributary length, l-<r Survey data and gravel quality for each point <S> 128 ® READ known data to compute flow coefficients "Surface Elevation \ N 0 known YES r Discharge and flow coefficient must be known Discharge must be known. Flow coefficient can be calculated Subroutine PRAM f Compute flow coefficient NO. Last set of known Data? WRITE section number and contributary length t 129 © © WRITE values of flow coefficients and corresponding values of surface elevation and discharge Select flow coefficient and tentative surface elevation Subroutine PRAM Assume a flow coefficient and calculate discharge 130 131 "PRAM" SUBROUTINE FLOW CHART FIGURE A2 Print out MULTIPLE CHANNEL CONDITION Calc. B increase by proportion & add to B T Calc. B. increment and add to B Calc. P, increase and'add to P. Calc. CHB once only Calc. Area increase and add to A if Calc. P increase and add to P Calc. area increase and add to A Calc. depth and add to DSUM © 132 Calc. B. increment by proportion and add to B > Calc. area increment and add to A Calc. P. increment by proportion and add to P Calculate Average Depth 133 APPENDIX B SPAWNING AND REARING FLOWS AS FUNCTIONS OF BASIN AND CHANNEL PARAMETERS M. R. C o l l l n g s CI9.74). has developed m u l t i p l e r e g r e s -s i o n equations f o r spawning and r e a r i n g flows In terms of b a s i n and stream channel c h a r a c t e r i s t i c s , based on a study of a number of streams i n western Washington. He found the f o l l o w i n g e i g h t parameters to be the most s i g n i f i c a n t : A - Drainage area MA - Mean b a s i n a l t i t u d e RA - Reach a l t i t u d e W - Reach width (bank f u l l width) GS - Gravel s i z e RS - Reach slope SF - Shape f a c t o r HR - H y d r a u l i c r a d i u s The shape f a c t o r i s obtained by measuring the water depths at the quarter p o i n t s of each, t r a n s e c t i n the reach, as-suming bank f u l l flow, and d i v i d i n g the average of the l a r g e r depth values by the average of the smaller depth, v a l u e s . C o l l l n g s provides equations f o r spawning and r e a r i n g flows, using one. or more of the parameters l i s t e d above. 134 He d i s t i n g u i s h e s h.e„t;w.een " p r e f e r r e d spawning d i s -charge", which i s e q u i v a l e n t to the optimum or peak v a l u e , and the "spawning s u s t a i n i n g d i s c h a r g e " , which i s that d i s c h a r g e , l e s s than the p r e f e r r e d d i s c h a r g e , where the percent r e d u c t i o n i n spawnable area becomes less: than the percent r e d u c t i o n i n d i s c h a r g e . The " p r e f e r r e d r e a r i n g d i s c h a r g e " i s assumed to be at the bend of the wetted width versus d i s c h a r g e curve ( F i g u r e 23). Table Bl; srhows values of spawning and r e a r i n g d i s -charges:, as c a l c u l a t e d from some of C o l l l n g s formulae, f o r sever-a l r i v e r s on which I have done some s t u d i e s . The c a l c u l a t e d values of the spawning flow f o r the Sooke River corresponds very w e l l to the graph, shown, i n F i g u r e 15. The r e a r i n g flow f o r the Sooke River was not s t u d i e d i n the f i e l d so that a comparison with the c a l c u l a t e d values was not made. The Coquitlam River p r e s e n t l y d r a i n s an e q u i v a l e n t watershed of 21 square m i l e s , as drainage from the remainder of the o r i g i n a l 94 square mile watershed i s d i v e r t e d f o r hydro-e l e c t r i c purposes. Observations, f i e l d measurements, and hydro-graph a n a l y s i s l e d to values of 100 c f s and 50 c f s f o r spawning and r e a r i n g flows, r e s p e c t i v e l y . This roughly corresponds to the values obtained from C o l l i n g * s formulae. T e n t a t i v e values f o r minimum spawning and r e a r i n g flows: were estimated f o r Norrfsh. Creek from hydrograph a n a l y s i s . As can be seen from the t a b l e they are only about a t h i r d of the c a l c u l a t e d v a l u e s , which means 135 that before f i n a l F i s h e r i e s Resource Maintenance Flows are set fo r N o r r i s h Creek a d d i t i o n a l f i e l d s t u d i e s should be done to check c o n d i t i o n s at flow l e v e l s from about 50 to 160 c f s . Values f o r the ungaged Tsulquate River have been tabul a t e d to help i n the a n a l y s i s of the Tsulquate system (see a l s o Appendix C). C o l l i n g s formulae seem to be u s e f u l f o r p r e l i m i n a r y a n a l y s i s and as a d e c k . o n other methods. The c o e f f i c i e n t s could p o s s i b l y be modified to b e t t e r r e f l e c t c o n d i t i o n s i n B r i t i s h . Columbia once s u f f i c i e n t data has been accumulated. SPAWNING AND REARING FLOWS FOR SALMON DERIVED FROM BASIN PARAMETERS A W YP = 12 A*fa 4 YP, = . 3 . 1 1 A , 4 Z w;5.04. • r Spawning Flow by other methods YS YS = 9 = 2 ,32 ,64 .675 .475 w .47 Spawning Flow-by other methods YR = 2.53 ~A'867 YR = .032 A - 3 2 7 M A ' 5 3 3 W'59' Rearing Flow by other methods SOOKE C0QUITLAM NORRISH TSULQUATE RIV E R R I V E R CREEK . R I V E R 108.4 21 94 44 23 140 60 150 100 80± 75Q 2000 2000 1780 750 257 87.9 234 142 93 268 88 262 155 106 200-300 220 72.8 200 120 77 229 72.7 222 130 87 200 100 60+ 147 35 130 67 38 9.4 56 157 90 40 50 50+ A = Basin area in square miles W = Bankfull width in feet MA = Mean Altitude of basin in feet above sea level YP = Preferred spawning flow in c.f.s. YS = Sustained spawning flow In c.f.s. YR = Optimum rearing flow In c.f.s. 137 APPENDIX C APPLICATION OF LOW FLOW ANALYSIS TO THE UNGAGED TSULQUATE RIVER The seven day low flow, two year recurrence i n t e r v a l , Q7L2, was c a l c u l a t e d f o r the Tsulquate. River as f o l l o w s : 1. Using a few flow measurements of the Tsulquate River and comparing them with data on the Ze b a l i o s River of the same p e r i o d . 2. Using a method developed by Orsborn (1976) using v a r i o u s watershed parameters and ana-l y z i n g the nearest gaged r i v e r s (Kokish, Benson and Z e b a l i o s ) . I have summarized h i s pro-cedure i n step form below; not only i s the Q7L2 value determined, but a l s o the values of a number of other parameters: A. Do the f o l l o w i n g f o r a l l the gaged streams i n the r e g i o n : 1. P l o t Q7L2 and Q7L20 a g a i n s t the b a s i n parameters: L T ( H ) 2, 3/2LI(H), LT(.H), L I ( D D ) 2 . S e l e c t the best b a s i n parameter. 2. P l o t Q7L2 and Q7L2Q on l o g - l o g paper a g a i n s t r e c u r r e n c e i n t e r v a l ( F i g u r e C l ) . Determine slope, p and i n t e r c e p t , Q7L1P from the graphs. C a l c u l a t e the average r a t i o s Q7LIP/Q7L2 and Q7L20/Q7L2 f o r the r e g i o n . 138 3. C a l c u l a t e **^H^—nS!**^^ = X f ° r each s t a t i o n . 30.0p A-4. P l o t Q7L2 a g a i n s t x o n l o g - l o g paper ( F i g u r e C2) . From the r e g r e s s i o n l i n e determine the c o e f f i c i e n t s f o r the equation Q7L2=k(x) m> B. Do the f o l l o w i n g f o r the ungaged stream under study: 1. C a l c u l a t e b a s i n parameters LT(H) 2 e t c . , and using the graphs prepared i n step A l , estimate Q7L2 and Q7L20. 2. P l o t Q7L2 and Q7L20 on l o g - l o g paper to determine the slope p. 3. C a l c u l a t e Q7L1P from the r a t i o determined In step A2, or read o f f graph p l o t t e d i n B2 . 4. C a l c u l a t e Q7L2 from the equation determined i n step A4. I f i t does not correspond s a t i s f a c o r i l y with the estimated Q7L2, another i t e r a t i o n of the c a l c u l a t i o n s i s necessary. The v a r i a b l e s used i n the a n a l y s i s are d e s c r i b e d below: A = Watershed area above gage, i n sq. mi. H ?= E l e v a t i o n d i f f e r e n c e between gage e l e v a t i o n and highest average continuous contour i n the watershed, i n f e e t . ^ = T o t a l length, of f i r s t order stream i n m i l e s . = T o t a l l e n g t h of streams- ( a l l orders) In m i l e s . 139 DD X k Q7L2 Q7L20 Q7LI.P Drainage d e n s i t y = L /A ( A 300.p I F' 3 w a t e r s h e d parameter A c o e f f i c i e n t Seven day low flow, 2 year r e c u r r e n c e i n t e r v a l Seven day low flow, 20 year recurrence i n t e r v a l H y p o t h e t i c a l value obtained by p r o j e c t i n g the l o g - l o g graph ( F i g u r e CI) to the one year l i n e , p = Slope of seven day low flow curve on the l o g -log graph. QAA = Average annual flow. Flow records were obtained on the Tsulquate River f o r a three month p e r i o d i n 1975. Two 7 day low flow p e r i o d s were ex t r a c t e d from t h i s data and compared with .7 day low flow data of the same period obtained f o r the Z e b a l i o s R i v e r : Z e b a l i o s R i ver 8HE6 Date 7 day low flow A. J u l y 27 - August 2/75 300 c f s B. Sept.26 - Oct. 2/75 208 c f s 185 c f s Recurrence I n t e r v a l 1.1 years 1. 4 years 2 . 0 years Tsulquate River A. J u l y 26 - August 1/75 5.0 c f s B. Sept 21 - 27/75 7.2 c f s or the Tsulquate.: A data, Q7L2 = B data, Q7L2 = 185 3 00. 185 2 08 x 5 = 3.1 c f s x 7.2 = 6.4 c f s 140 A t e n t a t i v e value of 5.0 c f s was taken as Q7L2 f o r the Tsulquate R i v e r . This t e n t a t i v e value of Q7L2 can be used i n s t e a d of going through steps A l and B l of the Orsborn procedure. The r e s u l t s of steps A2 to A4 are shown i n Table CI and Figures CI and C2. As there were records f o r two gages on the Koklsh which, had q u i t e d i f f e r e n t 7 day low flow values a double set of values was c a l c u l a t e d f o r the Tsulquate based on these two Koklsh gages. Rati o s of Q7L1P to Q7L2 and Q7L20 to Q7L2, as i n d i c a t e d i n step A2 were used to c a l c u l a t e Q7L1P and Q7L20 f o r the Tsulquate, u s i n g a t e n t a t i v e value of 7 c f s f o r the Tsulquate (obtained by a t r i a l r u n ) . Table CI shows that the Q7L2 values of 6.7 and 5.1 obtained check reasonably w e l l with those c a l c u l a t e d by comparison with the Z e b a l l o s r e c o r d s . Average values of 6.0 f o r Q7L2 and 2.0 f o r Q7L20 are about as c l o s e as would ever be needed to analyze low flows f o r f i s h e r i e s . The average annual flow, QAA, f o r the Tsulquate was als o c a l c u l a t e d , using the c o e f f i c i e n t , C, obtained by averaging the values f o r the Kokish. See l a s t e n t r i e s i n Table CI. P r e c i p i t a t i o n data, P, was taken from F i g u r e 27. 141 TABLE CI BASIN PARAMETERS AND 7-DAY LOW FLOWS FOR SEVERAL RIVERS ON VANCOUVER ISLAND BASIN PARAMETER KOKISH RIVER 8HF3 ZEBALLOS RIVER ZEBALLOS BENSON RIVER BENSON TSULQUATE RIVER TSULQUATE KOKISH RIVER 8HF1 A 104 6 9.. 8 81 23 120 H 0.8 9. 0.85 0 . 68 0 . 284 1.03 L i I l l 120.9 101.3 22.5 121 3/2LiH 148 . 2 15 4 .1 103.3 9 . 58 187 . 3 L T 27 5 211. 8 189.7 61.8 290 L TH 244 . 8 180 129 17 . 6 299 .3 h L TH 259 . 0 195.3 156.4 32 . 9 294.6 DD 2. 64 3 . 03 2.34 2 . 69 2.42 \|DD(Li) 180 210 . 4 155 36 . 9 188 . 2 X 5.1 51.4 6 . 8 . 18 !". 14 2.67 k 18.8 17.4 15 . 2 1 1 16 . 6 Q7L2 "%. 50 185 48± 1 6.7 | 5 .1 30 Q7L20 19 148 30± 2.6 1 1 . 6 | 7 Q7L1P 65 200 55 9.1 |I0.7 46 P .41 .10 . 20 | .43 |.65 .6.4 QAA 63 9. 111Q 7 02 103 635 P 130 200+ 180 100 130 L PA .04 7 . 07± .048 . 04 5 .041 

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