UBC Theses and Dissertations

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UBC Theses and Dissertations

An impact identification framework for large reservoirs Midgley, Peter Thomas 1972

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A N I M P A C T I D E N T I F I C A T I O N F R A M E W O R K F D R L A R G E R E S E R V O I R S by P E T E R "THOMAS M I D G L E Y B . A . , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1 9 7 0 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF 'SCIENCE " - -i n t h e S c h o o l o f Community and R e g i o n a l P l a n n i n g We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o th8 r e q u i r e d s t a n d a r d THE UNIVERSITY OF B R I T I S H COLUMBIA May, 1 9 7 2 -In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study, I f u r t h e r agree that p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . It i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . 2.7 Ci^J, School of Community and R e g i o n a l P l a n n i n g The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8 , Canada i i i ABSTRACT T h i s Study i s undertaken on the premise t h a t v i r t u a l l y a l l l a r g e r e s e r v o i r p r o j e c t s , i n a d d i t i o n to meeting c e r t a i n primary o b j e c t i v e s , cause c e r t a i n other secondary e f f e c t s , which are o f t e n u n a n t i c i p a t e d d u r i n g p l a n n i n g s t a g e s . Whether these secondary e f f e c t s are deemed to have p o s i t i v e .or n e gative v a l u e , t h e i r r e c o g n i t i o n d u r i n g the preo p e r a -t i o n a l p e r i o d would be advantageous. Hence, the o b j e c t i v e of the t h e s i s i s development of a check l i s t framework approach f o r i d e n t i f i c a t i o n of p h y s i c a l , b i o l o g i c a l , and human or c u l t u r a l e f f e c t s which stem from the c r e a t i o n of r e s e r v o i r s . The t h e s i s commences with a review of the secondary e f f e c t s of r e s e r v o i r s i n v a r i o u s p a r t s of the world. Both temperate and t r o p i c a l environments are c o n s i d e r e d , and both c o n c r e t e arch and e a r t h f i l l dams. The review forms the b a s i s f o r development of the impact i d e n t i f i c a t i o n framework. A stepped matrix approach i s used i n the framework. I n i t i a l l y , the p o t e n t i a l " o b j e c t i v e s " of r e s e r v o i r c r e a t i o n are i d e n t i f i e d . Meeting of these " o b j e c t i v e s " r e q u i r e s c e r t a i n "methods of e x e c u t i o n " , and these are i d e n t i f i e d on th8 second a x i s . The t h i r d a x i s i d e n t i f i e s the "impacts" of i v the v a r i o u s "methods of e x e c u t i o n " , and c o n t i n u e s w i t h an i n d i c a t i o n of the p o t e n t i a l " m u l t i p l e o r d e r consequences". The t h e s i s c o n c l u d e s as the framework approach i s a p p l i e d i n an i l l u s t r a t i v e manner to a proposed r e s e r v o i r development a t Moran Canyon on the F r a s e r R i v e r i n s o u t h -w e s t e r n 3 r i t i s h C olumbia. P o t e n t i a l i m p a c t s and c o n s e -quences are d i s c u s s e d , F i n a l l y , an assessment i s made as t o the u t i l i t y of the framework i d e n t i f i c a t i o n a p p r o a c h , and to methods by which the t e c h n i q u e might be improved. * * * S u p e r v i s o r V TA3LE OF CONTENTS A b s t r a c t T a ble of c o n t e n t s L i s t of f i g u r e s Acknowledgment FRONTISPIECE 1 Chapter 1 INTRODUCTION 2 Chapter 2 THE EFFECTS OF LARGE RESERVOIRS 15 THE PHYSICAL EFFECTS OF LARGE RESERVOIRS 16 H y d r o l o g i c a l e f f e c t s 16 S i l t a t i o n of r e s e r v o i r s S o l u t i o n o  s o l u b l e m a t e r i a l s i n the r e s e r v o i r bed Development of a r e s e r v o i r l i t t o r a l a r e a A b s o r p t i o n and seepage Groundwater c h a r g i n g E v a p o r a t i o n from r e s e r v o i r s M o d i f i c a t i o n of water t e m p e r a t u r e Downstream i c e c o n d i t i o n s Downstream e r o s i o n Downstream l a n d m o d i f i c a t i o n Downstream water d e f i c i t E s t u a r i n e s a l i n i t y C l i m a t i c e f f e c t s 37 E a r t h q u a k e s 39 THE BIOLOGICAL EFFECTS OF LARGE RESERVOIRS 41 E f f e c t s w i t h i n and i m m e d i a t e l y a d j a c e n t to l a r g e r e s e r v o i r s 42 E f f e c t of r e s e r v o i r s on r i v e r i n e oxygen and n u t r i e n t l e v e l s E f f e c t s of c l e a r i n g r e s e r v o i r b a s i n s The e f f e c t s of s i l t i n g Weed growth i n r e s e r v o i r s Shore v e g e t a t i o n around r e s e r v o i r s i i i v v i i i i x v i E f f e c t s on the fauna of the r e s e r v o i r area 55 Insect p o p u l a t i o n s The e f f e c t s of r e s e r v o i r s on the c a r r i e r s of d i s e a s e s The e f f e c t s on w i l d l i f e E f f e c t s on anadromous f i s h 61 Upstream m i g r a t i o n of f i s h Downstream m i g r a t i o n of f i s h E f f e c t s downstream from r e s e r v o i r s 66 E f f e c t s r e s u l t i n g from the r e l e a s e of f o u l e d waters E f f e c t s of the l o s s of downstream sediments E f f e c t of reduced flow on downstream f i s h E s t u a r i n e changes and o f f - s h o r e f i s h e r i e s The b i o l o g i c a l s t a b i l i z a t i o n of r e s e r v o i r s 70 THE HUNAN AND CULTURAL EFFECTS OF LARGE RESERVOIRS 73* Resettlement of indigenous p o p u l a t i o n s 75 Crowding of r e l o c a t e d people The lake as a s o c i a l b a r r i e r D i s e a s e : p h y s i c a l and p s y c h o l o g i c a l Changes i n land u t i l i z a t i o n and employment 81 F i s h i n g A g r i c u l t u r e R e c r e a t i o n Permanent l o s s of n a t u r a l and h i s t o r i c f e a t u r e s 84 The e f f e c t of u n p r e d i c t a b l e n a t u r a l events 86 Chapter 3 DEVELOPMENT OF AN IMPACT IDENTIFICATION FRAMEWORK 90 RECOGNITION OF THE NEED FOR IMPACT IDENTIFICATION 90 TECHNIQUES FOR IMPACT IDENTIFICATION AND AN IDEA 91 THE IMPACT IDENTIFICATION FRAinEWORK 99 v i i Chapter 4 APPLICATION OF THE FRAME WORK 104 THE PROPOSED RESERVOIR 104 CHARACTER OF THE PROPOSED RESERVOIR AREA 108 Geography and hydrology Climate and weather Ve g e t a t i o n W i l d l i f e Anadromous f i s h Access i n the proposed r e s e r v o i r area Economic s t r u c t u r e of the proposed r e s e r -v o i r area POTENTIAL IMPACTS OF THE f'lORAN RESERVOIR 115 C o n s t r u c t i o n of the dam ' D i s r u p t i o n of l o c a l p o p u l a t i o n - ^ I n i t i a l r e s e r v o i r f i l l i n g C r e a t i o n of an a r t i f i c i a l lake Downstream flow changes Anadromous f i s h Chapter 5 DISCUSSION AND CONCLUSION 123 BIBLIOGRAPHY 129 v i i i LIST OF FIGURES F i g u r e 1 P o s i t i o n of impact i d e n t i f i c a t i o n i n the assessment of a l t e r n a t i v e p l a n s F i g u r e 2 E n v i r o n m e n t a l impact m a t r i x f o r a phosphate m i n i n g l e a s e F i g u r e 3 L ayout of s tepped m a t r i x framework F i g u r e 4 Impact i d e n t i f i c a t i o n framework f o r l a r g e r e s e r v o i r s F i g u r e 5 The F r a s e r R i v e r B a s i n F i g u r e 6 Impact i d e n t i f i c a t i o n framework f o r l a r g e r e s e r v o i r s - - M o r a n Canyon Dam 93 95 97 p ocket 1.05 p ocket * * * ACKNOWLEDGMENT G r a t e f u l a p p r e c i a t i o n i s expressed to A s s i s t a n t P r o f e s s o r W i l l i a m E, Rees of the School of Community and Regional P l a n n i n g , and to A s s o c i a t e P r o f e s s o r Gary R. Gates of the Department of Geography, the U n i v e r s i t y of B r i t i s h Columbia, As a d v i s o r s f o r t h i s p r o j e c t , they have added s i g n i f i c a n t l y to the value of the e x e r c i s e with both con-s t r u c t i v e c r i t i c i s m s and u s e f u l i d e a s . Thanks are a l s o due to S h e i l a ffiidgley f o r help with t y p i n g , and many of the other odd tasks which are a s s o c i a t e d with the p r o d u c t i o n of a t h e s i s . P . T . IY1. 27 A p r i l , 1972 1 Man made l a k e s or r e s e r v o i r s a re u s u a l l y b u i l t f o r some " p r i m a r y " p u r p o s e , but the c o n s t r u c t i o n or pr e s e n c e of r e s e r v o i r s can c r e a t e " s e c o n d a r y " problems which may i n c l u d e economic l o s s and human s u f f e r i n g u n l e s s r e s e r v o i r p l a n n i n g i n i t s e a r l i e s t s t a g e s t h o r o u g h l y c o n s i d e r s both p r i m a r y and sec o n d a r y a s p e c t s . ( L a g l e r , 1969, p.. v i i ) 1. I N T R O D U C T I O N In t h i s s t u d y an attempt i s made t o de v e l o p a u s e f u l and comprehensive impact i d e n t i f i c a t i o n framework f o r l a r g e r e s e r v o i r s . R e s e r v o i r c o n s t r u c t i o n p r o j e c t s a re g e n e r a l l y i n i t i a t e d t o meet c e r t a i n o b j e c t i v e s such as the r e d u c t i o n of f l o o d h a z a r d , h y d r o e l e c t r i c g e n e r a t i o n , the s u p p l y of i r r i g a -t i o n w a t e r , the f a c i l i t a t i o n of n a v i g a t i o n , and the f a c i l i t a -t i o n of r e c r e a t i o n . In o r d e r t o a c h i e v s these o b j e c t i v e s o p e r a t i o n a l p r o c e d u r e s or "methods of e x e c u t i o n " must be f o l l o w e d . These methods might be summarized as "the con-s t r u c t i o n and o p e r a t i o n of the r e s e r v o i r s y s t e m " , however, they may a l s o be l i s t e d as components such as " c o n s t r u c t i o n of the dam", " i n i t i a l f i l l i n g o f the r e s e r v o i r " , " c r e a t i o n of a man-made l a k e " , and so on. C e r t a i n i m p a c t s on the p h y s i c a l , b i o l o g i c a l and human en v i r o n m e n t s r e s u l t from each "method o f e x e c u t i o n " , and the s e i m p a c t s have " m u l t i p l e o r d e r consequences". The o b j e c t i v e of the st u d y i s the development o f a comprehensive framework upon which these s e c o n d a r y e f f e c t s a r e i n d i c a t e d as l i n k a g e s of i m p a c t s and " m u l t i p l e o r d e r consequences", Ths framework may then s e r v e as a check l i s t f o r i d e n t i f i c a t i o n of p o t e n t i a l s e c o n d a r y e f f e c t s d u r i n g t h a p l a n n i n g s t a g e s f o r proposed r e s e r v o i r p r o j e c t s . The r a t i o n a l e f o r the s t u d y stems from the f a c t t h a t t o date the p l a n n i n g p r o c e s s has not g i v e n due r e g a r d t o the 3 comprehensive i d e n t i f i c a t i o n of i m p a c t s r e s u l t i n g from c o n -s t r u c t i o n and o p e r a t i o n of l a r g e r e s e r v o i r s . Some im p a c t s have been e x p e c t e d ; however, o t h e r i m p a c t s , which were g i v e n no c o n s i d e r a t i o n i n p l a n n i n g s t a g e s and which have come about i n a c o m p l e t e l y unexpected manner, may be documented f o r v i r -t u a l l y e v e r y l a r g e r e s e r v o i r p r o j e c t . Any c o n t r i b u t i o n t o -wards e n s u r i n g p r e i d e n t i f i c a t i o n o f i m p a c t s which might o t h e r w i s e o c c u r u n e x p e c t e d l y s h o u l d s e r v e t o improve the p l a n n i n g p r o c e s s . At t h i s p o i n t , no v a l u e judgement as t o whether the i m p a c t s and t h e i r consequences are o f p o s i t i v e or n e g a t i v e v a l u e i s i n t e n d e d . C e r t a i n l y , some o f the secondary e f f e c t s stemming from the development of l a r g e r e s e r v o i r s a re o f p o s i t i v e v a l u s t o man, though they a r e not i n c l u d e d as o b j e c t i v e s i n i n i t i a t i o n o f the r e s e r v o i r p r o j e c t . O t h e r s are of d e f i n i t e n e g a t i v e v a l u e , r e s u l t i n g i n human s u f f e r -i n g and economic l o s s . In e i t h e r c a s e , e a r l y r e c o g n i t i o n of i m p a c t s i s l i k e l y t o be b e n e f i c i a l ; p o s i t i v e i m p a c t s may be enhanced, and n e g a t i v e i m p a c t s may be m i n i m i z e d or may be met w i t h p l a n n e d r a t h e r than c r i s i s r e s p o n s e s . F u r t h e r , comprehensive i d e n t i f i c a t i o n and e v a l u a t i o n of i m p a c t s w i l l s e r v e t o improve the d a t a base upon which f e a s i b i l i t y c r i -t e r i a a r e t e s t e d and p r o j e c t f e a s i b i l i t y i s e s t a b l i s h e d . A l t h o u g h p r o j e c t e v a l u a t i o n i s not i n t e n d e d t o be a 4 c e n t r a l i s s u e i n t h i s s t u d y , the f e a s i b i l i t y c r i t e r i a which must be met t h r o u g h some form o f e v a l u a t i o n p r o c e d u r e s h o u l d be g i v e n b r i e f c o n s i d e r a t i o n . F i v e e l e m e n t s : e n g i n e e r i n g f e a s i b i l i t y , economic f e a s i b i l i t y , f i n a n c i a l f e a s i b i l i t y , p o l i t i c a l f e a s i b i l i t y and s o c i a l f e a s i b i l i t y , must be met i n o r d e r f o r the p l a n n i n g and d e c i s i o n making p r o c e s s e s t o d e t e r m i n e t h a t a program s h o u l d be i n i t i a t e d or t h a t a p r o -j e c t s h o u l d be c o n s t r u c t e d . The f i r s t c r i t e r i o n , e n g i n e e r i n g f e a s i b i l i t y , i s met i f a proposed p h y s i c a l s u p e r s t r u c t u r e i s c a p a b l e of b r i n g i n g about the s t a t e d o b j e c t i v e or o b j e c t i v e s . In the case o f r e s e r v o i r s , t h e s e o b j e c t i v e s a r e g e n e r a l l y d i r e c t e d towards o b t a i n i n g the d i r e c t and o b v i o u s o u t p u t s of the p r o j e c t such as the r e d u c t i o n o f f l o o d h a z a r d or the s u p p l y of i r r i g a t i o n w a ter. P o t e n t i a l o b j e c t i v e s i n v o l v i n g m i n i m i z i n g of n e g a t i v e i m p a c t s or m a x i m i z i n g of p o s i t i v e i m p a c t s may be o v e r l o o k e d a t an e n g i n e e r i n g l e v e l , s i m p l y because l a c k of i d e n t i f i c a -t i o n o f the i m p a c t s p r e v e n t s i n c o r p o r a t i o n of t h e i r m axi-m i z a t i o n or m i n i m i z a t i o n w i t h i n the e n g i n e e r i n g d e s i g n . E n g i n e e r i n g f e a s i b i l i t y i s met when i t i s shown t h a t the s t a t e d o b j e c t i v e s may be a c c o m p l i s h e d or may be o b t a i n e d , but comprehensive i d e n t i f i c a t i o n of i m p a c t s i s an u n n e c e s s a r y p r e r e q u i s i t e t o meet the c r i t e r i o n . 5 Economic f e a s i b i l i t y i s e s t a b l i s h e d " ... i f the t o t a l b e n e f i t s t h a t r e s u l t from the p r o j e c t exceed those which would a c c r u e w i t h o u t the p r o j e c t by an amount i n e x c e s s of the p r o j e c t c o s t " (James and L e e , 1971, p. 1 6 1 ) . Though t h e r e are many a d v o c a t e s of the b e n e f i t - c o s t a n a l y s i s t e c h n i q u e f o r e s t a b l i s h m e n t o f economic f e a s i b i l i t y , i t i s u n l i k e l y t h a t any would f a i l t o r e c o g n i z e the weakness i n h e r -ent i n i t s i n a b i l i t y t o c o r r e c t l y e v a l u a t e s e c o n d a r y and i n t a n g i b l e f a c t o r s , Many i m p a c t s and t h e i r consequences f a l l w i t h i n the groups of s e c o n d a r y and i n t a n g i b l e f a c t o r s . T h e i r r e c o g n i t i o n w i l l s e r v e t o improve the v a l i d i t y of the e s t a b -l i s h m e n t o f economic f e a s i b i l i t y , though even comprehensive i d e n t i f i c a t i o n of i m p a c t s cannot ensure a b s o l u t e v a l i d i t y o f p roven economic f e a s i b i l i t y . The a b i l i t y t o meat the c o s t of p r o j e c t i n s t a l l a t i o n and o p e r a t i o n , or f i n a n c i a l f e a s i b i l i t y , has l i t t l e t o do w i t h the i d e n t i f i c a t i o n and e v a l u a t i o n of i m p a c t s , beyond the f a c t t h a t f a u l t y economic a n a l y s i s may l e a d t o an i n v a l i d p i c t u r e of f i n a n c i a l f e a s i b i l i t y . P o l i t i c a l f e a s i b i l i t y i s e s t a b l i s h e d i f the r e q u i r e d p o l i t i c a l a p p r o v a l backs the p o s i t i o n of the d e c i s i o n makers. I f the g e n e r a l p u b l i c are i n v o l v e d , the f a i l u r e t o a c h i e v e comprehensive u n d e r s t a n d i n g of the i m p a c t s of l a r g e r e s e r v o i r s may r e s u l t i n the e s t a b l i s h m e n t of p o l i t i c a l 6 f e a s i b i l i t y on the b a s i s of i n c o m p l e t e e v a l u a t i o n . The f i n a l c r i t e r i o n , s o c i a l f e a s i b i l i t y , i s met i f i t can be shown t h a t the p o p u l a t i o n f o r whom the p r o j e c t i s b u i l t w i l l a c c e p t the o u t p u t s or o p p o r t u n i t i e s c r e a t e d , t u r n -i n g them i n t o the i n t e n d e d b e n e f i t s . The i n a b i l i t y t o a c h i e v e s o c i a l f e a s i b i l i t y may, i n i t s e l f , b r i n g unexpec-t e d i m p a c t s a f t e r a p r o j e c t i s c o m p l e t e d . However, i t can g e n e r a l l y be e s t a b l i s h e d t h a t the o u t p u t s of a proposed r e s e r v o i r p r o j e c t w i l l be a c c e p t e d and u t i l i z e d , but t h i s i n no way i n d i c a t e s comprehensive i d e n t i f i c a t i o n of the i m p a c t s r e s u l t i n g from the p r o j e c t . A f t e r c o n s i d e r a t i o n o f the f i v e e l e m e n t s of o v e r a l l p r o j e c t f e a s i b i l i t y i t may be c o n c l u d e d t h a t an i n c o m p l e t e f e a s i b i l i t y r a t i o n a l e g e n e r a l l y p r e c e d e s d e c i s i o n making on the i m p l e m e n t a t i o n of l a r g e p r o j e c t s . Though each element may be s a t i s f a c t o r i l y e v a l u a t e d i n i t s own r e s p e c t , t h e r e i s no guarantee t h a t a l l the f a c t o r s which might be e v a l u a t e d have i n f a c t been i n c l u d e d . The f a u l t r e s u l t s , not from the p r o c e s s o f c o n s i d e r i n g the i n d i v i d u a l f e a s i b i l i t y c r i t e r i a , but r a t h e r from the i n a b i l i t y t o i n c l u d e a l l r e l e v a n t f a c t o r s . These f a c t o r s which are o m i t t e d i n c l u d e the unex-p e c t e d i m p a c t s and t h e i r consequences. Any methodology which can be d e v e l o p e d t o a i d i n i d e n t i f i c a t i o n of t h e s e e f f e c t s s h o u l d , t h r o u g h c o n t r i b u t i n g t o the f e a s i b i l i t y assessment / / 7 o f each of the e l e m e n t s , have some u t i l i t y w i t h i n the c o n t e x t of p r o j e c t p l a n n i n g and subsequent d e c i s i o n making. Some of the e f f e c t s i d e n t i f i e d w i l l be f u l l y e x p e c t e d by those d e s i g n -i n g and a u t h o r i z i n g the p r o j e c t , however, i f s u c c e s s f u l the impact i d e n t i f i c a t i o n framework w i l l a l s o i n d i c a t e e f f e c t s which have o c c u r r e d u n e x p e c t e d l y i n p a s t p r o j e c t s and which are l i k e l y t o r e o c c u r i n c u r r e n t p r o j e c t s ; and e f f e c t s which have not o c c u r r e d i n the p a s t but may i n c u r r e n t or f u t u r e p r o j e c t s . S y s t e m a t i c impact i d e n t i f i c a t i o n has the p o t e n t i a l f o r i m p r o v i n g the data base f o r the e s t a b l i s h m e n t of f e a s i -b i l i t y c r i t e r i a . The methodology of t h i s s tudy i s e s s e n t i a l l y a p r a g m a t i c a p p r o a c h , based on i d e n t i f i c a t i o n of problems or consequences and r e c o g n i t i o n o f t h e i r c a u s e s . A major p a r t i s composed of documentation of the i m p a c t s which have been r e c o r d e d a f t e r the c o n s t r u c t i o n of l a r g e dams and r e s e r v o i r s a t s i t e s t h r o u g h o u t the w o r l d . T h i s s e c t i o n , r a t h e r than d e t a i l i n g the e f f e c t s of i n d i v i d u a l p r o j e c t s , as i s most common i n the l i t e r a t u r e , a t t e m p t s t o b r i n g f o r t h the e f f e c t s as c l a s s e s , i n d i c a t i n g as examples, p a r t i c u l a r p r o j e c t s where they have been r e c o r d e d . Documentation of t h i s s o r t may of c o u r s e , be of m i n i m a l i n t e r e s t t o those f a m i l i a r w i t h the s u b j e c t of l a r g e r e s e r v o i r s , and whose main i n t e r e s t i n t h i s s t u d y i s i n the development of the impact i d e n t i f i c a t i o n framework. On the o t h e r hand, f o r those who are l e s s f a m i l i a r w i t h the B s t u d y o f r e s e r v o i r s , the s e c t i o n s h o u l d p r o v i d e a u s e f u l background, and i n d i c a t e s o u r c e s of a d d i t i o n a l i n f o r m a t i o n which may be r e q u i r e d i n w o r k i n g t h r o u g h an impact i d e n t i f -c a t i o n framework f o r a proposed r e s e r v o i r p r o j e c t . As f a r as the s t u d y i t s e l f i s c o n c e r n e d , documentation of r e c o r d e d i m p a c t s and t h e i r consequences i s a n e c e s s a r y component, as i t must be r e l i e d upon as a major s o u r c e o f the s u b s t a n c e o f the i mpact i d e n t i f i c a t i o n framework. A broad g e o g r a p h i c p e r s p e c t i v e i s a t t e m p t e d , i n c l u d i n g e f f e c t s of r e s e r v o i r s i n both temperate and t r o p i c a l r e g i o n s . I t i s not i n t e n d e d t h a t a l l the i m p a c t s i d e n t i f i e d w i l l be a p p l i c a b l e t o any one r e s e r v o i r p r o j e c t , but r a t h e r t h a t the framework may s e r v e as a u s e f u l check l i s t d u r i n g the p l a n n i n g p r o c e s s . I t i s e s s e n t i a l a t t h i s p o i n t t o e x p l a i n the c o n t e x t i n which c e r t a i n t e r m i n o l o g y i s used l a t e r i n the s t u d y . The term " o b j e c t i v e s " r e f e r s t o the i n t e n d e d p r i m a r y o u t p u t s of the r e s e r v o i r o p e r a t i o n such as h y d r o e l e c t r i c g e n e r a t i o n , the r e d u c t i o n o f f l o o d h a z a r d , e t c . To a c h i e v e t h e s e o u t p u t s c e r t a i n o p e r a t i o n a l p r o c e d u r e s or "methods of e x e c u t i o n " must o be c a r r i e d o u t . These methods b r i n g about c e r t a i n s e c o n d a r y e f f e c t s or " i m p a c t s " which l e a d t o " m u l t i p l e o r d e r consequences". For the purpose of t h i s s t u d y , " f i n a l c o n s e -quences" are those a t which the " o b j e c t i v e t o method of e x e c u t i o n t o impact t o consequence" l i n k a g e i s t e r m i n a t e d . T h i s t e r m i n a t i o n g e n e r a l l y o c c u r s a t the p o i n t a t which the 9 consequence has a d i r e c t e f f e c t upon human a c t i v i t y , or a t the consequence which i m m e d i a t e l y p r e c e d e s t h i s p o i n t . I t w i l l be noted t h a t some of the " f i n a l consequences" w i l l be " f e e d b a c k s " or e f f e c t s on the achievement of the p r o j e c t ' s " o b j e c t i v e s " . By way of example, accomplishment of the " o b j e c t i v e " o f f a c i l i t a t i o n o f r e c r e a t i o n t h r o u g h the con-s t r u c t i o n of a dam and c r e a t i o n of a r e s e r v o i r , r e q u i r e s the "method of e x e c u t i o n " of c r e a t i o n of a man-made l a k e . One c o f the " i m p a c t s " which stems from t h i s method i s seepage, which may b r i n g the " f i n a l consequence" of i m p r o v i n g a g r i -c u l t u r a l o u t p u t t h r o u g h the s u p p l e m e n t a t i o n of groundwater, and which may have a " f e e d b a c k " by r e d u c i n g the amount of water a v a i l a b l e t o meet a second " o b j e c t i v e " - - g e n e r a t i o n o f h y d r o e l e c t r i c i t y . Though t h i s t e r m i n o l o g y i s g e n e r a l l y a v o i d e d i n the l e n g t h y c h a p t e r which f o l l o w s , i t w i l l be u s e f u l t o bear i t i n mind as the i m p a c t s stemming from l a r g e r e s e r v o i r c o n s t r u c t i o n p r o j e c t s are documented. S e l e c t i o n o f the parameters f o r the scope of the e f f e c t s t o be d i s c u s s e d i s a d i f f i c u l t t a s k . I d e a l l y , the p e r s p e c t i v e would be broad enough t o show the r e s e r v o i r ' s i n t e r r e l a t i o n s h i p w i t h f a c t o r s such as the n a t u r a l e n v i r o n m e n t , o t h e r p r o j e c t s , the economy, and human w e l f a r e g e n e r a l l y . Such a p e r s p e c t i v e would, however, be v e r y d i f f i c u l t t o a c h i e v e , A somewhat a r b i t r a r y d e c i s i o n must i n i t i a l l y be made as t o the c l a s s e s of i m p a c t s which are t o be c o n s i d e r e d . For the purposes of 10 t h i s s t u d y , the e f f e c t s a r e r e s t r i c t e d t o f a l l w i t h i n t h r e e b r o a d , i n t e r r e l a t e d c l a s s e s : p h y s i c a l e f f e c t s , b i o l o g i c a l e f f e c t s , and human or c u l t u r a l e f f e c t s . P h y s i c a l e f f e c t s i n c l u d e major changes i n the h y d r o l o g i c system, and gener-a l l y l e s s o b v i o u s changes i n the atmosphere and the e a r t h ' s c r u s t . B i o l o g i c a l e f f e c t s i n c l u d e changes i n both a q u a t i c and t e r r e s t r i a l b i o t i c c o m m u n i t i e s . For example, t h e p o p u l a t i o n s of some s p e c i e s may be e l i m i n a t e d by the con-s t r u c t i o n o f a l a r g e r e s e r v o i r , w h i l e the emergence or growth of p o p u l a t i o n s of o t h e r s p e c i e s may be encouraged, Human or c u l t u r a l i m p a c t s stem d i r e c t l y from r e s e r v o i r c o n s t r u c t i o n , and as consequences of p h y s i c a l and b i o l o g i c a l i m p a c t s . The i n t e r r e l a t i o n s h i p s between the t h r e e impact c l a s s e s a r e complex, and s m a l l i m p a c t s w i t h i n one of the c l a s s e s may have s i g n i f i c a n t consequences w i t h i n e i t h e r of the o t h e r two c l a s s e s . I t s h o u l d be made c l e a r t h a t the e f f e c t s d i s c u s s e d are t h o s e caused by the r e s e r v o i r p r o j e c t . No attempt i s made t o i d e n t i f y the e f f e c t s which would o c c u r w i t h o u t the accomplishment o f the r e s e r v o i r o b j e c t i v e s , and which a r e p r e v e n t e d by the s u c c e s s f u l o p e r a t i o n of the r e s e r v o i r . In a d d i t i o n t o e s t a b l i s h i n g the c l a s s e s of e f f e c t s which w i l l be c o n s i d e r e d , i t i s n e c e s s a r y t o j u s t i f y the p o i n t a t which t e r m i n a t i o n of consequences w i l l o c c u r . I t w i l l be found i n the f o l l o w i n g c h a p t e r t h a t most of the im p a c t s and consequences w i l l u l t i m a t e l y have an e f f e c t on man. 11 T h e r e f o r e , i t seems r e a s o n a b l e t o attempt the i d e n t i f i c a t i o n o f a sequence of consequences t o the p o i n t a t which man w i l l o b v i o u s l y be a f f e c t e d , or t o the p o i n t a t which r e m e d i a l measures must be e x e c u t e d t o reduce the l e v e l o f the consequence. T h i s i s the b a s i s f o r e s t a b l i s h m e n t of the " f i n a l consequence". The s t u d y i s composed of two main p a r t s . The f i r s t i s a d o c u m e n t a t i o n of the e f f e c t s caused by the c o n s t r u c t i o n of l a r g e r e s e r v o i r p r o j e c t s i n v a r i o u s p a r t s of the w o r l d . T h i s s e c t i o n a t t e m p t s t o p r e s e n t a comprehensive c r o s s s e c t i o n of e f f e c t s , c o v e r i n g those l i k e l y t o be e n c o u n t e r e d i n any p a r t i c u l a r r e s e r v o i r p r o j e c t or p r o p o s a l . I t i s a c r i t i c a l b a s i s f o r the second main p a r t o f the s t u d y , i n which impact i d e n t i f i c a t i o n schemes are d i s c u s s e d and the impact i d e n t i f i -c a t i o n framework f o r l a r g e r e s e r v o i r s i s p r e s e n t e d and e x p l a i n e d . To supplement the b a s i c s t u d y a t h i r d p a r t i s p r e s e n t e d i n which the impact i d e n t i f i c a t i o n framework i s a p p l i e d i n a b r i e f case s t u d y . T h i s l e a d s t o an o p p o r t u n i t y f o r e v a l u a t i o n o f the framework, and d i s c u s s i o n of i t s u t i l -i z a t i o n i n the c o n c l u s i o n . B e f o r e p r o c e e d i n g w i t h the s t u d y , i t i s w o r t h w h i l e t o c o n s i d e r b r i e f l y why an i n v e s t i g a t i o n of t h i s s o r t s h o u l d be u n d e r t a k e n . I s the p r e s e n t s i t u a t i o n w i t h r e s p e c t t o r e s e r -v o i r s and t h e i r unexpected e f f e c t s u n f a v o u r a b l e , and can the 12 p l a n n i n g p r o f e s s i o n o f f e r a u s e f u l s e r v i c e ? I t i s f e l t t h a t the answer t o both . q u e s t i o n s i s i n the a f f i r m a t i v e . C u r r e n t t e c h n o l o g y e n a b l e s use of a h i g h l e v e l of compe tence i n the d e s i g n and subsequent o p e r a t i o n of l a r g e r e s e r -v o i r p r o j e c t s . From an e n g i n e e r i n g v i e w p o i n t , achievement of the s t a t e d o b j e c t i v e s w i t h r e s p e c t t o the r e d u c t i o n of f l o o d h a z a r d , h y d r o e l e c t r i c g e n e r a t i o n , the s u p p l y of i r r i g a t i o n w a t e r , the f a c i l i t a t i o n o f n a v i g a t i o n and the f a c i l i t a -t i o n o f r e c r e a t i o n , may not be too g r e a t a problem. However i t i s i n f r e q u e n t t h a t p r i m a r y o b j e c t i v e s o f r e s e r v o i r development p r o j e c t s go bsyond t h e s e o b j e c t i v e s . C o n s i d e r a -t i o n o f se c o n d a r y e f f e c t s has not been c a r r i e d out i n a comprehensive manner i n the p a s t , and t h e r e i s l i t t l e i n the way of methodology t o ensure such a n a l y s i s even t o d a y . U n l e s s changes a r e mad8 i n the p l a n n i n g p r o c e d u r e i t i s d i f f i c u l t not t o con c u r w i t h the v i e w p o i n t of Thayer Scudder an a u t h o r i t y on p o p u l a t i o n r e l o c a t i o n r e s u l t i n g from i n u n d a -t i o n of r e s e r v o i r b a s i n s , when he s t a t e s , " I n y e a r s t o come, I b e l i e v e t h a t r e s e t t l e m e n t and development c o n n e c t e d w i t h the c r e a t i o n of l a r g e - s c a l e man-made l a k e s w i l l c o n t i n u e t o be c a r r i e d out on a p o o r l y t i m e d , t r i a l and e r r o r b a s i s u n t i l c e r t a i n b a s i c p o l i c y changes are made; changes which view dams not j u s t as a means f o r power g e n e r a t i o n and f l o o d c o n t r o l , but r a t h e r as a means f o r an i n t e g r a t e d r i v e r b a s i n development d e s i g n e d t o r a i s e the s t a n d a r d of l i v i n g of the t o t a l p o p u l a t i o n i n v o l v e d , both urban and r u r a l . The v e r y r e a l problem o f t i m i n g can be reduced i f the n e c e s s a r y f i s h e r i e s , h y d r o l o g i c a l , e c o l o g i c a l , s o c i a l and o t h e r s u r v e y s are i n c l u d e d w i t h i n the o r i g i n a l f e a s i b i l i t y s t u d i e s . Though these a r e a p t t o c o n t i n u e 13 over a number of y e a r s p r i o r t o s i t e s e l e c t i o n and the i n i t i a t i o n of dam c o n s t r u c t i o n ( f o l l o w i n g which a r i g i d s c h e d u l e i s e s s e n t i a l ) , t h e i r scope i s much t o o narrow. Though e x p a n s i o n would i n c r e a s e c o s t s , t h e s e a r e h a r d l y major i n terms of subsequent b e n e f i t s t o both the peopl e and the n a t i o n " ( S c u d d e r , 1966, p. 107). C l e a r l y , changes are r e q u i r e d i n r e s e r v o i r p l a n n i n g . How s h o u l d t h e s e changes come abo u t ? T h i s s t u d y i s u n d e r t a k e n w i t h the b e l i e f t h a t the s i t u a -t i o n o f r e s e r v o i r p l a n n i n g can be improved t h r o u g h d e v e l o p -ment o f a comprehensive methodology t o de t e r m i n e the p r o b a b l e e f f e c t s o f proposed p r o j e c t s . " ... A good d e a l o f f o r e s i g h t i s d e s i r a b l e t o a s s e s s the changes which w i l l o c c u r , t o p r e p a r e f o r them, t o take advantage of those t h a t a re f a v o u r a b l e , and t o ta k e measures a g a i n s t those t h a t are n o t . T h i s i n v o l v e s r e s e a r c h of a m u l t i - d i s c i p l i n a r y k i n d , w o r k i n g up the food c h a i n from the i n o r g a n i c and p h y s i c a l f a c t o r s , t h r o u g h the p l a n t l i n k s and the a n i m a l l i n k s t o man h i m s e l f " ( W o r t h i n g t o n , 1966, p. 4 ) . The m u l t i - d i s c i p l i n a r y n a t u r e of the problem p r o v i d e s an e x c e l l e n t o p p o r t u n i t y f o r the p l a n n i n g p r o f e s s i o n t o c o n t r i b -ute towards i t s improvement. The p r o f e s s i o n s h o u l d be a b l e t o o f f e r a b a s i c u n d e r s t a n d i n g , though not n e c e s s a r i l y h i g h e x p e r t i s e , i n each of the many f i e l d s of s t u d y which a r e i n v o l v e d . F u r t h e r , the p r o f e s s i o n s h o u l d be c a p a b l e of a p p l y i n g i t s own e x p e r t i s e i n the f i e l d o f a s s i m i l a t i n g m a t e r i a l f o r the a n a l y s i s of a l t e r n a t i v e s , and a s s e m b l i n g an o u t p u t i n d i c a t i n g the p r o b a b l e and p o t e n t i a l consequences of any p a r t i c u l a r r e s e r v o i r . 14 I f s u c c e s s f u l , t h i s s t u d y may c o n t r i b u t e towards i n s u r -i n g the harmonious development o f r e s e r v o i r p r o j e c t s . I t i s u n d e r t a k e n w i t h the c l e a r u n d e r s t a n d i n g t h a t even a f t e r i d e n t i f i c a t i o n of se c o n d a r y e f f e c t s , t h e r e are s t i l l gaps i n the a b i l i t y t o e v a l u a t e them. Perhaps new t e c h n i q u e s can be d e v i s e d e l s e w h e r e t o improve the e v a l u a t i o n p r o c e s s . I t must a l s o be s t r e s s e d t h a t the p l a n n e r has not the e x p e r t i s e t o m a n i p u l a t e the consequences which he p r e d i c t s . To t h i s end, the c o o p e r a t i o n of s p e c i a l i s t s i n a number of d i f f e r e n t f i e l d s i s r e q u i r e d i f r e s e r v o i r s are t o meet p r i m a r y o b j -e c t i v e s , m i n i m i z e n e g a t i v e e f f e c t s , and maximize p o s i t i v e e f f e c t s . 15 2 . T H E E F F E C T S O F L A R G E R E S E R V O I R S As not8d i n the i n t r o d u c t o r y c h a p t e r , the se c o n d a r y e f -f e c t s of r e s e r v o i r s have, f o r the purpose of t h i s s t u d y , been d i v i d e d i n t o t h r e e broad c l a s s e s : p h y s i c a l , b i o l o g i c a l , and human and c u l t u r a l . To p r e s e n t and d i s c u s s t h e s e i m p a c t s and t h e i r consequences i n an o r d e r l y manner, i t i s n e c e s s a r y t o f o c u s upon one c l a s s a t a t i m e . However, i n so d o i n g , i t must be born i n mind t h a t t h e r e a r e complex r e l a t i o n s h i p s of i m p a c t s and consequences w i t h i n and between c l a s s e s . A p h y s i c a l i m p act may l e a d t o a b i o l o g i c a l consequence. T h i s b i o l o g i c a l consequence i n t u r n may l e a d t o a feedback on one of the o b j e c t i v e o u t p u t s of the p r o j e c t and t o a consequence w i t h i n the human and c u l t u r a l c l a s s . To g i v e r e c o g n i t i o n t o a l l the i m p a c t s and consequences o f a l a r g e r e s e r v o i r p r o j -e c t i n a s u b j e c t i v e r e v i e w of the type which f o l l o w s i s o b v i o u s l y i m p o s s i b l e . The framework which i s d e v e l o p e d i n the f o l l o w i n g c h a p t e r may a i d i n c o n c e p t u a l i z a t i o n o f these r e l a t i o n s h i p s . T h i s c h a p t e r s e r v e s t o p r o v i d e a background f o r a p p r o a c h i n g the development of the impact i d e n t i f i c a t i o n framework. The background w i l l be enhanced i f the r e a d e r makes an e f f o r t t o c o n c e p t u a l i z e the l i n k a g e s between i m p a c t s and consequences. The o r d e r i n which the c l a s s e s of e f f e c t s a re p r e s e n t e d i s not e s p e c i a l l y c r i t i c a l , though the o r d e r f o l l o w e d here 16 i s c o n s i d e r e d t o be the most l o g i c a l . P h y s i c a l e f f e c t s are c o n s i d e r e d f i r s t , f o l l o w e d by b i o l o g i c a l and then human and c u l t u r a l e f f e c t s . I t may be a n t i c i p a t e d t h a t g e n e r a l l y p h y s i c a l i m p a c t s w i l l l e a d t o p h y s i c a l , b i o l o g i c a l and human and c u l t u r a l consequences. T h i s i s a g e n e r a l i z a t i o n , not a r u l e ; i t w i l l be obser v e d t h a t some b i o l o g i c a l i m p a c t s and some human and c u l t u r a l i m p a c t s stem d i r e c t l y from the methods o f e x e c u t i o n used t o meet r e s e r v o i r o b j e c t i v e s . THE PHYSICAL EFFECTS OF LARGE RESERVOIRS HYDROLOGICAL EFFECTS To u n d e r s t a n d the impact of a r e s e r v o i r on a w a t e r c o u r s e , i t i s n e c e s s a r y t o f i r s t f o c u s b r i e f l y on some of the hy d r o -l o g i c a l f a c t o r s i n the e v o l u t i o n of an u n d i s t u r b e d , n a t u r a l s t r e a m ; t h a t i s , a stream u n d i s t u r b e d by man, a n i m a l , or n a t u r a l e v e n t s such as t e c t o n i c a c t i v i t y , e a r t h q u a k e s or g l a c i a t i o n . As water i s p r e c i p i t a t e d t o the e a r t h , c o m p l e t -i n g the h y d r o l o g i c a l c y c l e , i t w i l l move downwards under the i n f l u e n c e o f g r a v i t y . Low p o i n t s i n the l a n d s c a p e w i l l a c c u -mulate water. I f they a r e open ended the water w i l l f l o w downward u n t i l i t r e a c h e s a d e p r e s s i o n from which i t can no l o n g e r c o n t i n u e t o f l o w , be i t a l a k e or the sea. As the water moves i t i s c a p a b l e of t h r e e r e l a t e d a c t i o n s : e r o s i o n , t r a n s p o r t a t i o n of p a r t i c u l a t e and d i s s o l v e d m a t e r i a l s and / / 17 d e p o s i t i o n . These t h r e e a c t i o n s are c r i t i c a l i n the d e v e l o p -ment of a w a t e r c o u r s e towards the l o w e s t s t a t e of f r e e energy. E r o s i o n by o v e r l a n d f l o w and stream f l o w w i l l remove p a r t i c u l a t e m a t e r i a l and s u b s e q u e n t l y wear more p a r -t i c u l a t e m a t e r i a l from the s o i l or r o c k over which the w a t e r -c o u r s e f l o w s . Depending on the s i z e of t h i s p a r t i c u l a t e m a t e r i a l , i t may be suspended l o a d ( h e l d i n s u s p e n s i o n by the water m o t i o n ) , or bed l o a d (moving i n an i r r e g u l a r man-ner a l o n g the stream bed). The f a s t e r moving the w a t e r -c o u r s e , and the g r e a t e r the volume of f l o w , the l a r g e r the s i l t l o a d may be. The amount of s i l t eroded and t r a n s p o r t e d i n any p a r t i c u l a r water b a s i n w i l l depend on the degree of c o n s o l i d a t i o n of e a r t h m a t e r i a l s , and t h e i r r e s i s t a n c e t o a b r a i s i o n . The n o r m a l - p a t t e r n f o r w a t e r c o u r s e s i s one i n which the g r a d i e n t i n c r e a s e s towards the headwaters, and l e v e l s towards the c o n f l u e n c e w i t h the s e a , l a k e or o t h e r r i v e r i n t o which i t f l o w s . Thus, the l o a d of eroded m a t e r i a l t r a n s -p o r t e d by a stream may b8 m a i n t a i n e d by the v e l o c i t y of the stream a t i t s headwaters, or by the q u a n t i t y of water i n i t s lower r e a c h e s . As the water s l o w s , the l o a d of eroded m a t e r i a l w i l l be d e p o s i t e d as s i l t s a l o n g the banks or i n a d e l t a a r e a a t the p o i n t of o u t f l o w . T h i s o v e r v i e w o f the n a t u r a l stream i s h i g h l y s i m p l i f i e d , but c o v e r s a s p e c t s which s e r v e t o complement the f o l l o w i n g d i s c u s s i o n . 18 S i l t a t i o n of r e s e r v o i r s S i l t a t i o n or s e d i m e n t a t i o n , whether unexpected or p l a n -ned f o r , o f t e n poses a problem of c o n s i d e r a b l e consequence i n both l a r g e and s m a l l r e s e r v o i r s . D e p o s i t i o n of the r i v e r ' s suspended and bed l o a d s may be e x p e c t e d t o come about as the r i v e r water slows i n the l a k e impounded be h i n d the dam. From a p u r e l y p h y s i c a l p o i n t of view t h i s phenomenon may range from i n c o n s e q u e n t i a l t o h i g h l y s i g n i f i c a n t . S e v e r a l r e s e r v o i r s have been r e n d e r e d v i r t u a l l y u s e l e s s t h r o u g h c o l -l e c t i o n of s e d i m e n t a r y m a t e r i a l . In Texas, New Lake A u s t i n on the C o l o r a d o R i v e r l o s t 95 p e r c e n t of i t s water c a p a c i t y t o s e d i m e n t s w i t h i n t h i r t e e n y e a r s , w h i l e i n A l g e r i a the M a l b r a R e s e r v o i r l o s t 58 p e r c e n t o f i t s c a p a c i t y w i t h i n twenty-two y e a r s ( 8 a r n i n g and Sanson, 1969),. B e f o r e c o n s t r u c t i o n of most l a r g e r e s e r v o i r s the s i l t l o a d of the r i v e r i s c a r e f u l l y c a l c u l a t e d , and where n e c e s s a r y compared as a r a t i o of p r o b a b l e a n n u a l sediment d e p o s i t i o n t o r e s e r v o i r volume. In the case of the Hoover Dam, i t has been c a l c u l a t e d t h a t each year the C o l o r a d o R i v e r d e p o s i t s 224 m i l l i o n t o n s of s i l t i n t o Lake Mead ( B a r d a c h , 1964). A l t h o u g h t h i s m a t e r i a l r a p i d l y b u i l t up t o a depth of a hundred f e e t i m m e d i a t e l y above the dam, i t i s e s t i m a t e d t h a t the r e s e r v o i r s h o u l d not f i l l w i t h s i l t s f o r some 500 y e a r s . F i g u r e s f o r the Aswan High Dam, i n which a p p r o x i m a t e l y 19 twenty p e r c e n t of the r e s e r v o i r volume has been a l o t t e d f o r s i l t b u i l d up g i v e a l i f e s p a n of s e v e r a l hundred y e a r s ( S i m a i k a , 1970). I t must be remembered, howevsr, t h a t e x t e n -s i v e s i l t a t i o n of a r e s e r v o i r w i l l reduce i t s s t o r a g e c a p a c -i t y , t h u s l o w e r i n g i t s p o t e n t i a l f o r h y d r o e l e c t r i c g e n era-t i o n , f l o o d h a z a r d r e d u c t i o n and i r r i g a t i o n . The p r o c e s s o f s i l t a t i o n g e n e r a l l y f o l l o w s a p a t t e r n i n r e s e r v o i r s . D u r i n g the p r o c e s s of f i l l i n g of the r e s e r -v o i r , the s i l t l o a d w i l l be dropped i n the zone i n which the r i v e r w a t e r s s l o w ( L e e n t v a a r , 1966). G r a d u a l l y t h i s zone w i l l move upstream u n t i l the headwaters of the r e s e r v o i r a r e r e a c h e d and the impounded l a k e l e v e l r e a c h e s i t s maximum. T h e r e a f t e r , the c u r r e n t i n r e s e r v o i r s g e n e r a l l y f o l l o w s the o l d r i v e r c h a n n e l towards the dam, w i t h o n l y moderate m i x i n g w i t h the l a k e water on e i t h e r s i d e . The c o a r s e r , h e a v i e r p a r t i c l e s of s i l t a r e d e p o s i t e d near the e n t r y of the r i v e r i n t o the r e s e r v o i r , and o n l y s m a l l amounts of the v e r y f i n e m a t e r i a l s p r e a d out and c i r c u l a t e around the l a k e ( N e e l , 1963). T h i s i n i t s e l f may pose a problem where a l a y e r of f i n e s e d i m e n t a r y m a t e r i a l might be c o n s i d e r e d a d e s i r a b l e method of r e d u c i n g the p e r m e a b i l i t y of a r e s e r v o i r bed. Here a g a i n , the Aswan High Dam may be c o n s i d e r e d as an example. I t was hoped t h a t the f i n e v o l c a n i c sediment c a r -r i e d by the N i l e from E t h i o p i a would s e t t l e on the 300 m i l e l o n g s i d e of the r e s e r v o i r composed of Nubian s a n d s t o n e s 20 ( C h u r c h , 1968; S t e r l i n g , 1971), T h i s has not been the c a s e ; most of the s i l t i s s e t t l i n g i n the deeper, o l d r i v e r c h a n n e l , a p p a r e n t l y l e a v i n g o p p o r t u n i t y f o r s i g n i f i c a n t seepage l o s s e s ( S t e r l i n g , 1971), The problem of s e d i m e n t a t i o n may be reduced by v a r i o u s t e c h n i q u e s i n the d e s i g n and o p e r a t i o n of dams and r e s e r v o i r s . S p i l l w a y s l o c a t e d a t c a r e f u l l y chosen h e i g h t s i n the dam w a l l may be opened d u r i n g p e r i o d s of water s u r p l u s , i n c r e a s i n g the c u r r e n t t h r o u g h the r e s e r v o i r and s l u i c i n g c o l l e c t e d s e d i -ments from the r e s e r v o i r bottom. However, i n s e v e r a l c a s e s the s p i l l w a y s have been l o c a t e d too low, and i n e f f e c t have been s e a l e d by s i l t b e f o r e b e i n g opened ( B e r t h i e r , e t a l . , 1970; L i e c h t i and H a e b e r l i , 1970), In F r a n c e , major m o d i f i -c a t i o n s were n e c e s s a r y on both the Chambon and the S a u t e t dams, the former a f t e r twenty y e a r s of o p e r a t i o n , the l a t t e r a f t e r t h i r t y - t w o . In each case the r e s e r v o i r s had t o be drawn-down and s i l t removal was f o l l o w e d by r e l o c a t i o n of s l u i c i n g s p i l l w a y s ( B e r t h i e r , e t a l . , 1970), In S w i t z e r l a n d , s i l t a t i o n t h r e a t e n e d the o p e r a t i o n o f the P a l a g n e d r a R e s e r v o i r , r e q u i r i n g the development of a f l o a t i n g dredge c a p a b l e of e x c a v a t i n g t o a depth of 50 meters f o r removal of s i l t s t o a p o i n t downstream from the dam. At the p o i n t of r i v e r e n t r y i n t o the r e s e r v o i r , a g r a v e l e x t r a c t i o n p l a n t was l o c a t e d t o remove the r i v e r ' s bed l o a d ( L i e c h t i and H a e b e r l i , 1 970). The c o s t of r e m e d i a l measures to remove s i l t i s / . / 21 l i k e l y t o be h i g h i n r e l a t i o n t o d e s i g n f e a t u r e s f o r f l u s h -i n g , and i s most u n l i k e l y t o be i n c l u d e d i n p r o j e c t p l a n n i n g c o s t s t u d i e s . Some s e d i m e n t a t i o n must be e x p e c t e d i n v i r t u a l l y a l l r e s e r v o i r s . In the p l a n n i n g s t a g e s of any l a r g e r e s e r v o i r p r o j e c t , due acc o u n t must be p a i d t o the p r o c e s s , not o n l y f o r i t s p h y s i c a l e f f e c t on the o p e r a t i o n o f the p r o j e c t , but a l s o f o r the r e l a t e d b i o l o g i c a l e f f e c t s which i t i n d u c e s . These r e l a t e d e f f e c t s a re r e v i e w e d i n subsequent s e c t i o n s . S o l u t i o n of s o l u b l e m a t e r i a l s i n the r e s e r v o i r bed L i t t l e a t t e n t i o n has been g i v e n t o s o l u b l e m i n e r a l s i n the beds of l a r g e r e s e r v o i r s . T h i s s i t u a t i o n i s u n d e r s t a n d -a b l e , as i t seems the d i s s o l u t i o n of m i n e r a l s has never c r e a t e d p a r t i c u l a r p r oblems. N e v e r t h e l e s s , the f a c t o r war-r a n t s p a s s i n g m e n t i o n , as i t c o u l d b r i n g about u n d e s i r a b l e c o nsequences, and might not be g i v e n c o n s i d e r a t i o n . In a r i d r e g i o n s where the e a r t h s u r f a c e has had a m i n i m a l amount of l e a c h i n g by p r e c i p i t a t i o n and r u n o f f , a v a r i e t y of s o l u b l e s a l t s may be e x p e c t e d a t or near the s u r f a c e . I n u n d a t i o n w i l l l e a d t o d i s s o l u t i o n of the s e compounds, b r i n g i n g c e r t a i n i o n s i n t o the r e s e r v o i r w a t e r s . I t i s e s t i m a t e d t h a t a p p r o x i m a t e l y twenty m i l l i o n t o n s of m i n e r a l s i n c l u d i n g s u l p h a t e s , c a l c i u m , sodium, p o t a s s i u m , and c h l o r i d e d i s s o l v e d i n t o Lake Mead on 22 the C o l o r a d o R i v e r w i t h i n the f i r s t t h i r t e e n y e a r s a f t e r Hoover Dam was c l o s e d ( N e e l , 1963), No h a r m f u l e f f e c t s were noted i n t h i s c a s e ; however, i t i s q u i t e c o n c e i v a b l e t h a t m i n e r a l c o n t e n t c o u l d r e n d e r the water u n f i t f o r a v a r i e t y of p u r p o s e s such as d o m e s t i c s u p p l y , i n d u s t r i a l s u p p l y , or even the s u p p o r t of a l a k e f i s h e r y . Development of a r e s e r v o i r l i t t o r a l a r e a The l i t t o r a l a r e a of l a r g e r e s e r v o i r s may be d i v i d e d i n t o t h r e e d i s t i n c t z o n e s : the permanent beach, the draw-down zone, and the p e r m a n e n t l y submerged zone. Because the draw-down of a r e s e r v o i r i s u s u a l l y f a r g r e a t e r than the h i g h t o low water f l u c t u a t i o n of a n a t u r a l l a k e , the l i t t o r a l s t r i p w i l l be wide by c o m p a r i s o n . The r a t e of f o r m a t i o n of the s h o r e l i n e of a r e s e r v o i r i s g r e a t e s t when the r e s e r v o i r i s new, and slows as a dynamic e q u i l i b r i u m o f m a t u r i t y i s r e a c h e d . The s t e e p n e s s o f the r e s e r v o i r shore and the r e s i s t a n c e of the m a t e r i a l of which i t i s composed a r e major f a c t o r s d e t e r m i n i n g the f i n a l p h y s i c a l form of the l i t t o r a l a r e a . As c u r r e n t s i n a r e s e r v o i r are m i n i m a l , e x c e p t a t the i n f l o w , the major f o r c e s h a p i n g the shore w i l l be wind c r e a t e d waves. Beach a r e a s may form e i t h e r from m a t e r i a l eroded from the s h o r e , or from r i v e r s e diments c a r r i e d t o the shore by waves. I f the, underwater shore s l o p e i s s t e e p , waves w i l l not break 23 u n t i l t h e y r e a c h the beach, and e r o s i o n landward may be e x p e c t e d i f the shore m a t e r i a l has low r e s i s t a n c e . I f , by c o n t r a s t , the shore s l o p e s g e n t l y under w a t e r , waves w i l l break b e f o r e r e a c h i n g the beach, and landward e r o s i o n may be slowed c o n s i d e r a b l y . D u r i n g p e r i o d s of draw-down, an under-water bar formed by the b r e a k i n g waves may be exposed. As the l i t t o r a l g r a d i e n t d e v e l o p s , so t o o a l i n e a l development t a k e s p l a c e , Where s h o r e s are d i s s e c t e d by i n l e t s and b a y s , t h e r e w i l l be a tendency towards g r e a t e r e r o s i o n of p r o m o n t o r i e s and l e s s e r e r o s i o n of i n l e t s . T h i s may be e x p e c t e d , as the waves w i l l l o s e much of t h e i r energy on the p r o m o n t o r i e s , e s p e c i a l l y i f , as i s u s u a l l y the c a s e , the water o f f th e s e a r e a s i s q u i t e deep r e l a t i v e t o t h a t i n i n l e t s . In summary, "the common b a s i c tendency o f d e v e l o p -ment o f the s h o r e l i n e i s e q u a l i z a t i o n of i t s c o n t o u r " ( Z h i v a g o and Lange, p, 580, 1969), The draw-down zone of r e s e r v o i r s i s one of the p r i n c i p a l f e a t u r e s d i f f e r e n t i a t i n g them from n a t u r a l l a k e s . I t may be a n t i c i p a t e d t h a t the draw-down zone of a r e s e r v o i r shore of s h a l l o w g r a d i e n t w i l l become a v e r y wide s t r i p of l a n d a t low water. A 30 f o o t draw-down of a r e s e r v o i r w i t h s h o r e s of f i v e p e r c e n t g r a d i e n t , f o r example, w i l l uncover a 600 f o o t wide s t r i p o f shore l a n d . U n t i l the shore r e a c h e s a s t a t e of even s l o p e , and a smooth l i n e of water t o l a n d c o n t a c t , 24 the d e p r e s s i o n s i n t h i s m a r g i n a l a r e a may become s t a g n a n t ponds. The c h a r a c t e r of t h i s p a r t of the l i t t o r a l a r e a may have an a d v e r s e e f f e c t on many of the a c t i v i t i e s o c c u r r i n g a l o n g the s h o r e . I t may be c o n c l u d e d t h a t c a r e f u l p l a n n i n g o f the l i t t o r a l a r e a o f a r e s e r v o i r i s a p r e r e q u i s i t e t o s u c c e s s f u l m u l t i -purpose r e s e r v o i r o p e r a t i o n . The shore cannot be c o n s i d e r e d as s i m p l y the o r i g i n a l c o n t o u r o f the proposed r e s e r v o i r l e v e l , but r a t h e r must be c o n t e m p l a t e d as something e v o l v i n g from a l o n g term g e o m o r p h o l o g i c a l p r o c e s s . C a r e f u l a t t e n t i o n t o the draw-down zone may l e a d t o m i n i m i z a t i o n of i t s n e g a t i v e e f f e c t s . A b s o r p t i o n and seepage The r e l a t e d p r o c e s s e s o f a b s o r p t i o n and seepage may have q u i t e d i f f e r e n t e f f e c t s on the o p e r a t i o n of a r e s e r v o i r . The m a t e r i a l o f which the r e s e r v o i r bed i s composed w i l l a l l o w some p e n e t r a t i o n or a b s o r p t i o n of s t o r e d water. A b s o r p -t i v e c a p a c i t y must be met b e f o r e the r e s e r v o i r r e a c h e s an o p e r a t i o n a l s t a g e . However, once r e a c h e d , i t w i l l no l o n g e r reduce the amount of i n f l o w i n g water a v a i l a b l e f o r the uses f o r which the r e s e r v o i r i s i n t e n d e d . Seepage, by c o n t r a s t , may cause c o n s i d e r a b l y g r e a t e r problems. I t i n v o l v e s the 25 p e r c o l a t i o n of water from the r e s e r v o i r t o some o t h e r a r e a , thus e l i m i n a t i n g i t s a v a i l a b i l i t y f o r r e s e r v o i r use. I f the r e s e r v o i r bed i s composed i n p a r t of a permeable r o c k zone, or i f the dam does not form an e f f e c t i v e s e a l w i t h the v a l l e y w a l l s , some water w i l l e s c a p e , e i t h e r t o an a r e a below the dam, or an a r e a o u t s i d e the w a t e r s h e d . Though some seepage i s e x p e c t e d a t most dams, and i s c o n s i d e r e d normal f o r e a r t h f i l l dams, f a i l u r e t o f o r e c a s t the e x t e n t of seepage may p r e v e n t o p e r a t i o n of the r e s e r v o i r i n the p l a n n e d manner. Both a b s o r p t i o n and seepage a r e b e i n g c l o s e l y watched a t the Aswan High Dam, I t i s e s t i m a t e d t h a t t o a c h i e v e s a t -u r a t i o n of the b a s i n w i t h i n which the r e s e r v o i r i s s i t u a t e d , 48 b i l l i o n c u b i c meters of water w i l l be a b s o r b e d , a volume e q u a l t o about 30 p e r c e n t of the r e s e r v o i r ' s t o t a l c a p a c i t y (Abu-UJafa and L a b i b , 1970), I f seepage was not a p r o b l e m , t h i s s i t u a t i o n would s i m p l y amount t o b u i l d i n g up an o p e r a t i n g b a l a n c e , a f t e r which a l l f u r t h e r i n f l o w c o u l d be r e l i e d upon to meet o t h e r r e q u i r e m e n t s . U n f o r t u n a t e l y , t h i s i s not the s i t u a t i o n a t Aswan. A l t h o u g h o p i n i o n s as t o the magnitude o f the problem d i f f e r , seepage from the r e s e r v o i r w i l l s i g n i f i -c a n t l y reduce u s a b l e water ( S t e r l i n g , 1971, Abu-Wafa and L a b i b , 1970). S t e r l i n g a t t r i b u t e s a l o s s of f i f t e e n m i l l i o n c u b i c meters a n n u a l l y t o seepage from the r e s e r v o i r b a s i n t o o t h e r a r e a s . Though t h i s seepage a l o n g w i t h o t h e r f a c t o r s t h r e a t e n s t o p r e v e n t the r e s e r v o i r from f i l l i n g by the e a r l y 26 1980's as p l a n n e d , i t may a t some f u t u r e date be h i g h l y advantageous. In the event t h a t a number of wet y e a r s e l i m i n a t e the r e s e r v o i r ' s c a p a c i t y t o h o l d back f l o o d waters f o r r e g u l a t e d d i s c h a r g e t o the l o w e r N i l e , seepage from the upper 30 meter zone which i s i n t e n d e d f o r f l o o d water s t o r a g e w i l l reduce the amount of water which must be passed downstream. A b s o r p t i o n and seepage must be c a r e f u l l y c o n s i d e r e d i n p l a n n i n g a r e s e r v o i r p r o j e c t . A b s o r p t i o n i s o f i m p o r t a n c e i n s o t t i n g the date f o r i n i t i a l f i l l i n g of a r e s e r v o i r , w h i l e seepage may be a f a c t o r which p r e v e n t s a r e s e r v o i r p r o j e c t from y i e l d i n g i t s i n t e n d e d b e n e f i t s . Ground water c h a r g i n g D i r e c t l y r e l a t e d t o seepage of- water t h r o u g h permeable underground r o c k s t r a t a i s the p o t e n t i a l f o r ground water c h a r g i n g . In t h i s case seepage may be h i g h l y d e s i r a b l e t o the p o i n t t h a t i t s h o u l d be i n c o r p o r a t e d w i t h i n the o p e r a t i n g g o a l s of a m u l t i - p u r p o s e r e s e r v o i r development. Through the p r o c e s s of ground water c h a r g i n g i t may be p o s s i b l e t o have water move underground t h r o u g h a n a t u r a l a q u i f e r t o a n o t h e r a r e a , where water near or a t the ground s u r f a c e can be put t o good use. I t i s hoped t h a t some of the water s e e p i n g from the Aswan High Dam r e s e r v o i r w i l l u l t i m a t e l y supplement the water s u p p l y i n oases l o c a t e d many m i l e s t o the e a s t i n the Nubian d e s e r t . 27 C h a r g i n g of underground a q u i f e r s w i t h r e s e r v o i r waters may not always b r i n g b e n e f i c i a l e f f e c t s . The Sennar i r r i g a -t i o n r e s e r v o i r i n Sudan has charg e d a q u i f e r s , but " ... near the f r o n t i e r ( w i t h E t h i o p i a ) the water t a b l e , r a i s e d by the r e s e r v o i r , caused the F a r a s b a s i n to be f l o o d e d w i t h s a l t w a t e r . The s a l t c r e a t e d an a g r i c u l t u r a l problem ... " ( L e w i s , 1966, p. 4 5 ) . In c o n t r a s t , R o o s e v e l t L a k e , impounded b e h i n d the Grand Coulee Dam i s c o n s i d e r e d t o have had a h i g h l y d e s i r a b l e c h a r g i n g e f f e c t . " ... Today the o r i g i n a l s eventeen l a k e s i n the p r o j e c t a r e a have been j o i n e d by a h o s t of new l a k e s . These l a k e s r o s e out of the ground as i r r i g a t i o n water i n the a r e a caused the water l e v e l i n the s o i l t o r i s e and t h i s h i g h e r water t a b l e e n l a r g e d some of the o l d l a k e s , formed new ones, and caused s t i l l o t h e r s t o merge i n t o l a r g e r b o d i e s of water" (U.S. Department of the I n t e r i o r , 1964, p. 2 6 ) . To a c c u r a t e l y p r e d i c t the p o t e n t i a l and e f f e c t of c h a r g i n g underground a q u i f e r s would be a v e r y d i f f i c u l t t a s k , as i t would r e q u i r e a l m o s t p e r f e c t knowledge o f s u b s u r f a c e g e o l o g y . The c o s t o f r e m e d i a l measures t o r e l i e v e d e l e t e r i -ous e f f e c t s i s h i g h i f not p r o h i b i t i v e , so when r e s e r v o i r s are c o n s t r u c t e d t h e r e i s a d e f i n i t e degree of u n c e r t a i n t y as t o the u l t i m a t e e f f e c t of ground water c h a r g i n g and movement of water t h r o u g h underground a q u i f e r s . E v a p o r a t i o n from r e s e r v o i r s N a t u r a l e v a p o r a t i o n may cause a c o n s i d e r a b l e l o s s of water from l a r g e r e s e r v o i r s . The p o t e n t i a l f o r e v a p o r a t i o n 28 w i l l be d e t e r m i n e d by a c o m b i n a t i o n o f t e m p e r a t u r e , h u m i d i t y , and a i r m o t i o n . R e s e r v o i r s i n windy t r o p i c a l a r i d a r e a s w i l l have a v e r y h i g h p o t e n t i a l f o r e v a p o r a t i o n , w h i l e those i n the humid t r o p i c s and i n temperate a r e a s w i l l be l e s s prone t o s u b s t a n t i a l e v a p o r a t i o n l o s s e s . At Lake N a s s e r , p r e c o n -s t r u c t i o n e s t i m a t e s of e v a p o r a t i o n were proven wrong when the dam was c l o s e d . C o r r e c t a l l o w a n c e s had not been made f o r the i n c r e a s e d p o t e n t i a l f o r e v a p o r a t i o n because of w i n d s , and as a r e s u l t l o s s e s a r e one and o n e - h a l f t i m e s t h o s e e x p e c t e d , or some f i f t e e n b i l l i o n c u b i c meters a n n u a l l y ( S t e r l i n g , 1971). For s m a l l r e s e r v o i r s i t may be p o s s i b l e to reduce e v a p o r a t i o n by c o v e r i n g the water s u r f a c e w i t h a mono-molecular l a y e r of a non v o l a t i l e s o l u t i o n which w i l l e f f e c t i v e l y s e a l the water from exposure t o a i r . On l a r g e r e s e r v o i r s t h i s p r o c e d u r e would be r e n d e r e d v i r t u a l l y i n e f f e c t i v e by c o n t i n u o u s wave a c t i o n . Thus, e v a p o r a t i o n remains a pro b l e m , e s p e c i a l l y from l a r g e r e s e r v o i r s i n windy a r i d a r e a s , and from those w i t h wide expanse r e l a t i v e t o s h a l l o w d e p t h . M o d i f i c a t i o n of Water Temperature C r e a t i o n of a r e s e r v o i r b r i n g s about m o d i f i c a t i o n o f r i v e r i n e water temperature i n two ways. F i r s t , i t b r i n g s about a l a k e l i k e s i t u a t i o n i n which a u s u a l l a k e t e m p e r a t u r e p a t t e r n may be e x p e c t e d . S e c o n d l y , i t m o d i f i e s the 29 t e m p e r a t u r e of w a t e r s r e l e a s e d t h r o u g h the dam. Large r e s e r v o i r s s i m u l a t e the normal p a t t e r n of l a k e t e m p e r a t u r e changes. In the warm seasons the s u r f a c e w a t e r s warm q u i c k l y r e l a t i v e t o the bottom w a t e r s , and i n t h e i r expanded, lower s p e c i f i c g r a v i t y s t a t e remain a t the l a k e s u r f a c e . F r e q u e n t l y a r e g i o n o f r a p i d t e m p e r a t u r e g r a d i e n t , known as a t h e r m o c l i n e , forms a d i s t i n c t s t r a t i f i c a t i o n between the l i g h t e r , warmed s u r f a c e water and the h e a v i e r , c o o l e r water a t the bottom. There i s m i n i m a l c i r c u l a t i o n between the two l a y e r s , though i n the case of r e s e r v o i r s , the c u r r e n t t h r o u g h the impounded waters which i s i n d u c e d by i n f l o w and o u t f l o w may encourage m i x i n g . In the c o o l e r months o f the year the s u r f a c e water w i l l g r a d u a l l y l o s e i t s h e a t , f i n a l l y r e a c h i n g the p o i n t a t which i t s t e m p e r a t u r e (and t h e r e f o r e d e n s i t y ) i s e q u a l t o t h a t of the bottom w a t e r , and the l a k e mixes or o v e r t u r n s . O v e r t u r n i s an i m p o r t a n t phenomenon i n l a r g e r e s e r v o i r s , as i t i s th r o u g h ~ t h i s p r o c e s s t h a t oxygen i s c a r r i e d t o the r e s e r v o i r bottom, when the c o o l e d , oxygenated s u r f a c e water d i s p l a c e s warmer, l e s s dense bottom w a t e r . The bottom w a t e r s , which may have become d e v o i d of oxygen d u r i n g the p e r i o d i n which the l a k e has been s t r a t i f i e d , now c i r c u l a t e t o the s u r f a c e and have an o p p o r t u n i t y t o absorb a t m o s p h e r i c oxygen. As the downstream movement of water i s slowed or h a l t e d / 30 i n a r e s e r v o i r , i t s o p p o r t u n i t y t o g a i n or l o s e energy from the atmosphere i n the form o f heat i s i n c r e a s e d . Water r e l e a s e d from the dam may t h u s , depending on the s e a s o n , have a h i g h e r or lo w e r t e m p e r a t u r e than t h a t which the n a t -u r a l s t r e a m would have had a t the same time of the y e a r . The p a t t e r n which must be e x p e c t e d i s one which w i l l " d e l a y r i v e r t e m p e r a t u r e r i s e i n the s p r i n g and d e c l i n e i n the autumn" ( N e e l , 1963, p. 589). One.of the e f f e c t s o f t h i s t e m p e r a t u r e m o d i f i c a t i o n i s d i s c u s s e d i n the f o l l o w i n g s e c t i o n . Downstream i c e c o n d i t i o n s As n o ted i n the p r e v i o u s s e c t i o n the normal r i v e r i n e p a t t e r n of t e m p e r a t u r e f l u c t u a t i o n s i s r e t a r d e d by c r e a t i o n of a r e s e r v o i r . T h i s may have a n o t i c e a b l e impact on i c e f o r m a t i o n i n r i v e r s downstream from dams i n temperate a r e a s . R e l a t i v e l y warm r e s e r v o i r waters may p r e v e n t the n a t u r a l p a t t e r n o f i c e f o r m a t i o n , as has been the case w i t h r i v e r s i n the Chesapeake Bay a r e a . T h i s i n t u r n has p r e v e n t e d the p r e v i o u s a n n u a l s c o u r i n g of the r i v e r b e d by i c e d u r i n g the break up p e r i o d ( C r o n i n , 1967). On r i v e r s i n a r e a s c o l d e r than the Chesapeake Bay a r e a , i c e may u l t i m a t e l y form, but because of the s l o w warming of r e s e r v o i r water l i t t l e m e l t -i n g w i l l be a c c o m p l i s h e d by the u n d e r f l o w i n g r i v e r water i n the s p r i n g , and break up w i l l be slowed c o n s i d e r a b l y . 31 M o d i f i c a t i o n s o f the n a t u r a l p a t t e r n o f i c e f o r m a t i o n of l a r g e r i v e r s may have a c o n s i d e r a b l e e f f e c t on o t h e r a s p e c t s o f the environment. Downstream e r o s i o n As the s e d i m e n t s from the headwaters of a watershed are m o s t l y t r a p p e d by l a r g e r e s e r v o i r s , t h e i r l o s s from the r i v e r regime downstream from a dam may be e x p e c t e d t o pose a number of problems. I t seems t o be g e n e r a l l y agreed t h a t the e r o s i v e c a p a c i t y of c l e a n water i s g r e a t e r than t h a t of water c a r r y i n g a heavy sediment l o a d , perhaps because of the i n c r e a s e i n speed of the water ( A k s o y , 1970; P r e t i o u s , 1972; S i m a i k a , 1970), D e g r a d a t i o n o f a r i v e r bed downstream from a dam i s p r o b a b l e , and problems e n c o u n t e r e d a f t e r the i n i t -i a t i o n of o p e r a t i o n of a r e s e r v o i r i n c l u d e u n d e r c u t t i n g of the f o u n d a t i o n s of b r i d g e s , d y k e s , and o t h e r r i v e r bank f a c i l i t i e s . A l t h o u g h the l o s s of s i l t and the d o w n c u t t i n g of the r i v e r i s u s u a l l y a p r o b l e m , the f a c t o r may be advan-tageous i n r i v e r s i n which the s i l t l o a d hampers o t h e r r i v e r u s e s , and s e d i m e n t a r y d e p o s i t s r e q u i r e r e m o v a l . In a d d i t i o n t o i n c r e a s e d e r o s i o n r e s u l t i n g from l o s s of the r i v e r ' s s e d i m e n t a r y l o a d , a f a r more r a p i d form of e r o -s i o n may take p l a c e i m m e d i a t e l y below a dam. T h i s r e s u l t s when the o u t f l o w s t r u c t u r e s are i m p r o p e r l y l o c a t e d and they 32 " ... i n d u c e e r o s i o n of what was f o r m e r l y the a l l u v i a l s i d e of the ri v / e r ... f o l l o w e d by a bank-to-bank s h i f t -i n g of c u t t i n g and d e p o s i t i o n t h a t removes sandbars of l o n g s t a n d i n g and f i l l s i n e s t a b l i s h e d c h a n n e l s " ( N e e l , 1963, p. 589). A l l o w a n c e f o r downstream e r o s i v e e f f e c t s must be made when dams are c o n s t r u c t e d t o c r e a t e r e s e r v o i r s . There may be l i t t l e i n the way o f p r e v e n t i t i v e d e s i g n t h a t can be i n c l u d e d i n the c o n s t r u c t i o n of the dam, so c o s t s w i l l f o l l o w f o r c o r r e c t i v e measures r e q u i r e d downstream a f t e r the p r o j e c t i s i n o p e r a t i o n . Downstream l a n d m o d i f i c a t i o n V a r i o u s changes may be brought upon the r i v e r banks, e s t u a r i n e a r e a s , and the c o a s t o f the water body which a r i v e r f l o w s i n t o , e i t h e r from the l o s s o f s i l t i n a r i v e r downstream from a dam or from m o d i f i c a t i o n of the r i v e r i n e f l o w p a t t e r n . The n a t u r a l p a t t e r n of r i v e r s i s one i n which a heavy s i l t l o a d i s c a r r i e d downstream i n the r i v e r ' s h i g h water or f l o o d p e r i o d , f o l l o w e d by a d e c r e a s i n g t o a l m o s t n o n e x i s t e n t l o a d a t o t h e r t i m e s of the y e a r . The s i l t f i l l s a v a r i e t y of i m p o r t a n t f u n c t i o n s i n c l u d i n g the b u i l d i n g up o f n a t u r a l l e v e e s a l o n g the r i v e r banks, the s t a b i l i z a t i o n " or e x p a n s i o n of e s t u a r i n e d e l t a s , and the p r o v i s i o n of beach m a t e r i a l t o be moved by c u r r e n t s a l o n g the shore of the r e c e i v i n g water body. A f t e r the dam becomes o p e r a t i o n a l , sediment i n the l o w e r r e a c h e s of the r i v e r i s reduced .. 33 c o n s i d e r a b l y , or may be t o t a l l y e l i m i n a t e d . Not o n l y i s the m a t e r i a l t r a p p e d b e h i n d the dam, but a l s o the r e g u l a t e d r i v e r may l a c k s u f f i c i e n t speed and volume t o bear a s i g n i f i c a n t l o a d . In the case of the N i l e R i v e r t o d a y , the sediment l o a d has been so reduced by b u i l d i n g of the Aswan High Dam, t h a t p a r t s of the d e l t a a r e a are e r o d i n g i n t o the M e d i t e r r a n e a n Sea a t a r a t e of s e v e r a l yards a n n u a l l y ( S t e r l i n g , 1 9 7 1 ). Other problems are c r e a t e d a l o n g the r i v e r where the a n n u a l f l o o d has been e l i m i n a t e d and the r i v e r banks no l o n g e r r e c e i v e an a n n u a l d e p o s i t of s e d i m e n t s , i m p o r t a n t both t o m a i n t a i n s o i l f e r t i l i t y and t o s t a b i l i z e the r e l a t i o n s h i p between l a n d and r i v e r . A n other i n t e r e s t i n g example of l a n d m o d i f i c a t i o n r e s u l t i n g from dam b u i l d i n g i s documented by 8 e r t h i e r , e t a l , ( 1 9 7 0 ) . In t h i s case the dam r e g u l a t e d water f l o w t o a low l e v e l i n comparison t o t h a t i n the n a t u r a l r i v e r s i t u a t i o n . Downstream, a f a s t , minor t r i b u t a r y , b e a r -i n g a heavy l o a d of s e d i m e n t s , merged w i t h the r i v e r . P r i o r t o dam c o n s t r u c t i o n , the volume and speed of the main r i v e r was s u f f i c i e n t t o bear the t r i b u t a r y ' s l o a d downstream, how-ever w i t h the main r i v e r ' s f l o w r e g u l a t e d t o a reduced volume, the speed was no l o n g e r s u f f i c i e n t t o bear the s i l t m a t e r i a l . G r a v e l , sand, and mud bars b u i l t up a t the c o n f l u e n c e o f the two w a t e r c o u r s e s . As w i t h many of the o t h e r p h y s i c a l e f f e c t s of l a r g e dams and r e s e r v o i r s , t h e r e i s not a g r e a t d e a l t h a t can be done 34 to p r e v e n t downstream l a n d m o d i f i c a t i o n . I t may be p o s s i b l e t o f l u s h s i l t t h r o u g h the r e s e r v o i r and r e l e a s e s u f f i c i e n t water t o sc o u r the r i v e r bed, but such measures are o n l y a p a r t i a l s i m u l a t i o n of n a t u r e , and the e f f e c t s w i l l a t most be reduced. Other c o s t l y r e m e d i a l measures such as s t a b i l i z a -t i o n o f the d e l t a a r e a s and c o n s t r u c t i o n o f s p i t s t o d i v e r t c u r r e n t s from s h o r e l a n d may a l s o be n e c e s s a r y . Downstream water d e f i c i t A l a c k of water r e l e a s e from a r e s e r v o i r may r e s u l t i n i n a b i l i t y t o bear the sediment l o a d , as has a l r e a d y been d i s c u s s e d , but t h i s i s not the o n l y a r e a i n which water d e f -i c i t i s a f a c t o r . A l s o common i s the s i t u a t i o n where f l o w r e g u l a t i o n by a dam or d i v e r s i o n from a r e s e r v o i r can l e a d t o d r y i n g of downstream l a k e s and marshes. T h i s s i t u a t i o n i s p r e v a l e n t i n a r e a s where the dammed r i v e r i s a p r i n c i p a l s o urce of water s u p p l y t o a l a k e i n a r e g i o n of minor r e l i e f . At l e a s t two a r e a s have been a f f e c t e d by d r y i n g r e s u l t i n g from f l o w r e d u c t i o n . In s o u t h w e s t e r n A s i a the l e v e l s of the A r a l and C a s p i a n Seas have been d r o p p i n g i n r e c e n t y e a r s . T h i s i s the r e s u l t of damming the i n f l o w i n g r i v e r s f o r i r r i g a t i o n and f o r h y d r o e l e c t r i c g e n e r a t i o n . Between 1961 and 1969, the A r a l Sea dropped over one meter, a s i g n i f i c a n t amount f o r an i n l a n d sea w i t h an average depth o f a p p r o x i m a t e l y t w e n t y - f i v e meters (Goldman, 1970), The C a s p i a n Sea has / 35 d r o p p e d 2.5 m e t e r s i n t h e p a s t two d e c a d e s f o r t h e same r e a s o n . U l t i m a t e l y t h e s e s e a s may be no more t h a n s a l t m a r s h e s i f i n f l o w i s n o t a u g m e n t e d . I n C a nada t h e p r o b l e m o f w a t e r d e f i c i t r e s u l t i n g f r o m dam c o n s t r u c t i o n i s c u r r e n t l y u n d e r i n v e s t i g a t i o n i n t h e d e l t a a r e a o f L a k e A t h a b a s c a ( E n v i r o n m e n t C a n a d a , 1 9 7 1 a ) . The c r e a t i o n o f t h e W i l l i s t o n L a k e r e s e r v o i r on t h e P e a c e R i v e r h a s a l t e r e d a c o m p l e x n a t u r a l s i t u a t i o n i n w h i c h w a t e r f r o m t h e P e a c e a n n u a l l y f l o o d e d t h e d e l t a a r e a and f l o w e d i n t o L a k e A t h a b a s c a d u r i n g t h e h i g h w a t e r p e r i o d . Now, w i t h t h e r e d u c e d f l o w , most o f t h e d e l t a a r e a i s b y p a s s e d by t h e w a t e r s o f t h e P e a c e , w h i c h f l o w d i r e c t l y i n t o t h e S l a v e R i v e r a s t h e y w o u l d d u r i n g t h e l o w w a t e r p e r i o d ( S c h u l t z , e t a l . , 1 9 7 0 ) . B r e a k d o w n o f t h i s c o m p l e x a n n u a l f l o w r e v e r -s a l s i t u a t i o n i s l e a d i n g t o d r y i n g o f d e l t a l a k e s and c o n v e r -s i o n o f d e l t a m a r s h e s t o d r y l a n d . I n o r d e r t o p r e s e r v e t h e d e l t a e n v i r o n m e n t a c u r r e n t c r i s i s p r o g r a m o f r e m e d i a l m e a s u r e s i s u n d e r w a y , i n c l u d i n g c o n s t r u c t i o n o f a r o c k - f i l l dam t o i m p o u n d e n o u g h w a t e r t o i n u n d a t e t h e d e l t a i n t h e s p r i n g o f 1 9 7 2 , T h e r e i s e v e r y i n d i c a t i o n t h a t t h e p r o b l e m w h i c h h a s a r i s e n i n t h i s p a r t i c u l a r d e l t a a r e a was n o t g i v e n a n y a t t e n t i o n i n p l a n n i n g t h e c r e a t i o n o f W i l l i s t o n r e s e r v o i r . The e f f e c t o f r e d u c t i o n o f d o w n s t r e a m d i s c h a r g e c a n n o t / 36 be p r e d i c t e d with p r e c i s i o n i n the p l a n n i n g of a r e s e r v o i r p r o j e c t . The matter should r e c e i v e a t t e n t i o n , though, espe-c i a l l y i n cases where downstream r e l e a s e s w i l l be permanently reduced by d i v e r s i o n . A l s o worthy of c o n s i d e r a t i o n i s the e f f e c t of gross r e d u c t i o n of downstream d i s c h a r g e d u r i n g i n i t i a l r e s e r v o i r f i l l i n g . To t h i s end i t may be advanta- -geous to slow the f i l l i n g o p e r a t i o n i n order to maintain the minimum d e s i r a b l e downstream flow. E s t u a r i n e s a l i n i t y A t h i r d c l a s s of problems may a r i s e from water flow r e d u c t i o n caused by a r e s e r v o i r p r o j e c t . T h i s i s i n the f i e l d of changes i n e s t u a r i n e s a l i n i t y brought about through changes i n d i l u t i o n by the r i v e r water, and i s common among r i v e r s f l o w i n g from dams to s a l t water. Soon a f t e r c l o s u r e of the U o l t a Dam at Akosombo, i t was noted that lowering of water flow i n the lower V o l t a was l e a d i n g to a deeper t i d a l p e n e t r a t i o n (Ewer, 1966), The changing s a l i n i t y g r a d i e n t had an e f f e c t on v a r i o u s forms of l i f e i n the e s t u a r i n e a r e a . S i m i l a r l y , i t has been found t h a t the l o s s of waters from the N i l e R i v e r i n the Mediterranean Sea has promoted a flow of the h i g h l y s a l i n e water of the Red Sea i n t o the e a s t e r n Mediterranean ( S t e r l i n g , 1971). T h i s i n t u r n i s l e a d i n g to changes i n marine f l o r a and fauna, and s a l i n i t y of p r e v i o u s l y f r e s h water marsh and crop a r e a s . Although r i v e r flow /. / / 37 r e d u c t i o n beyond a c e r t a i n p o i n t i s h a r m f u l , some f l o w modi-f i c a t i o n may b r i n g more b e n e f i c i a l r e s u l t s . I t has been noted t h a t a f a s t f l o w of f r e s h water w i l l s t a y above h e a v i e r s a l i n e w a t e r s i n e s t u a r i e s , w h i l e a s l o w e r f l o w w i l l r e t a r d s t r a t i f i c a t i o n and encourage m i x i n g ( C r o n i n , 1971). In t h i s manner oxygen may be c a r r i e d t o the e s t u a r y bottom, a zone which o t h e r w i s e would be h e l d w i t h o u t oxygen by the s t r a t i f i -c a t i o n of the f r e s h water o v e r f l o w . CLIMATIC EFFECTS I t i s w e l l known t h a t l a r g e l a k e s m o d i f y the c l i m a t e o f the s u r r o n d i n g l a n d , and i t s h o u l d be e x p e c t e d t h a t i n a s i m i l a r way the l a n d s u r r o u n d i n g l a r g e man-made l a k e s w i l l undergo a c l i m a t i c m o d i f i c a t i o n . T h i s m o d i f i c a t i o n may i n c l u d e an i n c r e a s e i n r a i n f a l l , r e d u c t i o n of t e m p e r a t u r e e x t r e m e s , and r e t a r d a t i o n of s e a s o n a l changes. The c l i m a t i c e f f e c t of U o l t a Lake i n Ghana i s b e i n g c a r e f u l l y watched and s t a t i s t i c a l e x p e r i m e n t s have been c o n -d u c t e d t o see i f t h e r e i s a s i g n i f i c a n t change (De-Heer Amissah, 19.69), I t i s t o be e x p e c t e d t h a t the warm monsoon a i r masses would have the g r e a t e s t c a p a c i t y f o r e v a p o r a t i o n and t h a t t h e i r a c c u m u l a t e d m o i s t u r e w i l l p r e c i p i t a t e on n o r t h e a s t e r n Ghana, w h i l e s o u t h e r n Ghana w i l l r e c e i v e a l e s -s e r amount of p r e c i p i t a t i o n from the c o o l e r n o r t h e a s t e r l y / 38 winds. To e s t a b l i s h whether t h i s i s i n f a c t the case w i l l r e q u i r e o b s e r v a t i o n over a number of y e a r s , but i t i s u n l i k e -l y t h a t such m a c r o - c l i m a t i c e f f e c t s w i l l be s i g n i f i c a n t . C l i m a t i c changes of l e s s e r a r e a l e x t e n t , however, have a l r e a d y been e s t a b l i s h e d (De-Heer Amissah, 1969), At K e t e - K r a c h i , on the shore of the new V o l t a L a k e , monthly t e m p e r a t u r e max-imums and minimums are r e s p e c t i v e l y lower and h i g h e r than i n the p e r i o d p r i o r t o r e s e r v o i r c o n s t r u c t i o n , H u m i d i t y a t t h i s l o c a t i o n has a l s o r i s e n . C l i m a t i c e f f e c t s of K a r i b a Lake on the Zambezi R i v e r a r e e x p e c t e d , but seem not t o be w e l l documented. I t i s hoped t h a t K a r i b a w i l l i n c r e a s e h u m i d i t y s u f f i c i e n t l y t o cause an i n c r e a s e i n p r e c i p i t a t i o n , and t h i s i n t u r n w i l l l e a d t o i n c r e a s e d a g r i c u l t u r a l p r o d u c t i v i t y on the escarpments be-tween which the r i v e r f l o w s ( C o l e , 1960), In temperate a r e a s r e s e r v o i r s may a l s o be e x p e c t e d t o cause c l i m a t i c changes. A proposed major water p r o j e c t i n the James Bay a r e a of Canada would c r e a t e l a r g e l a k e s which d u r i n g the w i n t e r would be i c e c o v e r e d . I t i s p o s t u l a t e d t h a t the e f f e c t of th e s e l a k e s w i l l be a l o c a l l e n g t h e n i n g o f the w i n t e r , brought on by the l e n g t h of time r e q u i r e d t o mel t t h r o u g h the i c e ( H a r e , 1972). C l i m a t i c changes i n d u c e d by l a r g e r e s e r v o i r s w i l l not 39 be o f g r e a t magnitude. However, the i m p o r t a n c e of t h e s e changes s h o u l d not be u n d e r e s t i m a t e d . In one c a s e , i n c r e a s e d h u m i d i t y and e x t r a p r e c i p i t a t i o n may open up an a g r i c u l -t u r a l p o t e n t i a l , w h i l e i n a n o t h e r the r e d u c t i o n i n temper* a t u r e extremes may promote b r e e d i n g of the c a r r i e r s of d i s e a s e s . F o r e t h o u g h t must be g i v e n t o these and o t h e r p o s s i b i l i t i e s , i f p o s i t i v e e f f e c t s are t o be enhanced and n e g a t i v e e f f e c t s met w i t h p r e p a r a t i o n f o r a m i n i m i z a t i o n of consequences. EARTHQUAKES I t i s now r e c o g n i z e d t h a t s e i s m i c a c t i v i t y can be c o r -r e l a t e d w i t h the l o a d i n g o f the e a r t h ' s c r u s t b r o u g h t on by the f i l l i n g o f a l a r g e r e s e r v o i r . Two f a c t o r s may be seen as i n d u c i n g e a r t h q u a k e s or t r e m o r s . The s heer weight of the impounded water w i l l cause a s i n k i n g of the e a r t h ' s c r u s t , marked by sudden movements a l o n g s h e e r zones. These move-ments are f u r t h e r i n d u c e d by water p e n e t r a t i o n a l o n g f a u l t s and s h e a r s , which s e r v e s t o l u b r i c a t e movement between two rock s u r f a c e s t h a t would o t h e r w i s e be h e l d immobile by f r i c t i o n . In e i t h e r c a s e , s e i s m i c a c t i v i t y may r e s u l t . There i s no e v i d e n c e however, t h a t e a r t h q u a k e s are caused by r e s e r v o i r f i l l i n g ; r a t h e r t h e i r o c c u r r e n c e i s i n d u c e d a t an e a r l i e r time than would have been the case i n a n a t u r a l s i t u a t i o n . / / / 40 E x t e n s i v e damage has been caused by e a r t h q u a k e s a s s o c i a t e d w i t h r e s e r v o i r l o a d i n g i n v a r i o u s p a r t s of the w o r l d . The most d e v a s t a t i n g s e i s m i c a c t i v i t y o c c u r r e d i n 1967, about 150 m i l e s s o u t h e a s t of Bombay, I n d i a , near the Koyna r e s e r v o i r . Some two-hundred deaths were caused i n t h i s e a r t h q u a k e . In Greece t h e r e has been c o n s i d e r a b l e s e i s m i c a c t i v i t y i n the v i c i n i t y o f the Marathon and Kremasta dams. T h i s has l e d t o l a n d slumps and s l i d e s , d e s t r u c t i o n of 480 houses and damage of over 2,000 o t h e r s ( R o t h e , 1968). Much s e i s m i c a c t i v i t y i s a s s o c i a t e d w i t h the f i l l i n g o f Lake K a r i b a , w i t h two shocks r e g i s t e r i n g magnitudes of 5.8 (Gough and Gough, 1969). Mo s i g n i f i c a n t damage i s a t t r i b u t e d t o these r e l a t i v e l y h i g h magnitude s h o c k s . Other r e c o r d s of s e i s m i c a c t i v i t y are a v a i l a b l e from most, i f not a l l , l a r g e r e s e r v o i r s where equipment i s a v a i l a b l e f o r measurement. I t may be c o n c l u d e d t h a t : " ... t h e r e a r e s t r o n g i n d i c a t i o n s t h a t impounding of r e s e r v o i r s , l o a d i n g of l a k e s and c h a n g i n g t h e i r l e v e l s can i n d u c e s e i s m i c a c t i v i t y i n the immediate a r e a , p a r -t i c u l a r l y i f the a r e a i s g e o t e c t o n i c a l l y u n s t a b l e . Moreover the above mentioned d i s t u r b a n c e s on the c r u s t can t r i g g e r o f f e a r t h q u a k e s even i n a r e a s where e a r t h -quakes a re r a r e , but where s t r e s s and s t r a i n r e l a t i o n s i n the roc k a re such t h a t d i s t u r b a n c e s on the s u r f a c e cause e l a s t i c rebound i n depth. These d e l i c a t e s t r e s s - s t r a i n c o n d i t i o n s are u s u a l l y d i f f i c u l t t o d e t e c t i n what are g e n e r a l l y known as s t a b l e a r e a s , and appear o n l y when l o a d i n g i s a l r e a d y i n p r o g r e s s . " ( K a i l and C h a r a l a m b a k i s , 1970, p. 798). In p l a n n i n g l a r g e r e s e r v o i r s a l l o w a n c e s h o u l d be made f o r the p o s s i b i l i t y of e a r t h q u a k e s . A l t h o u g h they may not o c c u r , 41 the magnitude of d i s a s t e r p o s s i b l e , w a r r a n t s c o n s i d e r a b l e c o n c e r n , and the p l a n n i n g of r e l i e f measures i n case t h e y may a t some time become n e c e s s a r y . * * * T h i s c o n c l u d e s the s e c t i o n d e a l i n g w i t h p h y s i c a l e f f e c t s . I t w i l l be seen i n the f o l l o w i n g two s e c t i o n s of the c h a p t e r , which c o v e r b i o l o g i c a l , -and human and c u l t u r a l e f f e c t s , t h a t t h e r e a re e x t e n s i v e r e l a t i o n s h i p s between the t h r e e c a t e g o r -i e s , and t h a t many of the l a t t e r consequences stem from changes i n the environment which are e i t h e r i n d u c e d by, or are a p a r t o f the p h y s i c a l e f f e c t s which have been c o n s i d e r e d , THE BIOLOGICAL EFFECTS OF LARGE RESERVOIRS The c r e a t i o n of a l a r g e r e s e r v o i r has a c o n s i d e r a b l e e f f e c t on f l o r a and f a u n a , not o n l y w i t h i n the r e s e r v o i r b a s i n , but a l s o around i t s p e r i p h e r y and downstream from the dam. The e f f e c t s a re f e l t over a l a r g e a r e a , i n p a r t because of the complex r e l a t i o n s h i p s and i n t e r d e p e n d e n c e s between d i f f e r e n t s p e c i e s . To f u l l y document the e f f e c t of removal of even one s p e c i e s from the s t r u c t u r e of a complex ecosystem would be a t a s k a t l e a s t e q u a l i n magnitude t o the p r e p a r a t i o n o f t h i s p a p e r . An e q u a l l y comprehensive d o c u m e n t a t i o n of the e f f e c t s of changes i n or removal of 42 the number of s p e c i e s i n v o l v e d i n a l a r g e r e s e r v o i r s i t u a t i o n i s l i k e l y i m p o s s i b l e . O b v i o u s l y , t h i s s e c t i o n does not a t -tempt such r i g o r , but r a t h e r f o c u s e s on the b i o l o g i c a l im- : p a c t s which have had an o b v i o u s e f f e c t on man a t v a r i o u s r e s e r v o i r s i t e s , and seeks t o i n d i c a t e the consequences of thes e i m p a c t s . EFFECTS WITHIN AND IMMEDIATELY ADJACENT TO RESERVOIRS E f f e c t of r e s e r v o i r s on r i v e r i n e oxygen and n u t r i e n t l e v e l s B e f o r e c o n c e n t r a t i n g d i r e c t l y on b i o l o g i c a l e f f e c t s , , i t i s n e c e s s a r y t o c o n s i d e r the b i o l o g i c a l l y r e l e v a n t p h y s i c a l and c h e m i c a l s i t u a t i o n w i t h i n a newly formed man-made l a k e . T h i s might be c o n s i d e r e d a p h y s i c a l i m p a c t , and as such would be e x p e c t e d i n the p r e v i o u s s e c t i o n , however, the b i o l o g i c a l development brought about by the r e s e r v o i r i s so d i r e c t l y r e l a t e d t o the p h y s i c a l and c h e m i c a l c o m p o s i t i o n of the new l a k e t h a t the d i s c u s s i o n f a l l s most l o g i c a l l y as a p r e f a c e t o coverage o f the b i o l o g i c a l e f f e c t s . With the i n u n d a t i o n of a t e r r e s t r i a l l a n d a r e a the v e g e t a t i o n of the a r e a w i l l be drowned. A n a t u r a l c o n s e q -uence i s d e c o m p o s i t i o n of the p l a n t and o t h e r o r g a n i c m a t t e r a t a r a t e governed g e n e r a l l y by the a v a i l a b i l i t y of oxygen and the t e m p e r a t u r e . Thus, w i t h the c l o s i n g of a dam and 43 subsequent f l o o d i n g of l a n d , t h e r e w i l l be a heavy demand f o r d i s s o l v e d oxygen around the submerged o r g a n i c m a t e r i a l . G e n e r a l l y , the r i v e r s on which r e s e r v o i r s are l o c a t e d have a h i g h d i s s o l v e d oxygen c o n t e n t u n t i l impoundment o c c u r s . T h i s l e v e l i s m a i n t a i n e d i n the n a t u r a l r i v e r i n e c o n d i t i o n s by exposure of the water t o the atmosphere, and c o n s t a n t m i x i n g as i t f l o w s or c a s c a d e s downwards, and t o a l e s s e r degree by gas exchange from a q u a t i c p l a n t s . But, soon a f t e r a dam i s c l o s e d and d e c o m p o s i t i o n of t e r r e s t r i a l p l a n t s b e g i n s , the oxygen c o n t e n t of the impounded water i s reduced or a l t o -g e t h e r e l i m i n a t e d . Lake V o l t a , impounded be h i n d the Akosom-bo Dam i n Ghana i s t y p i c a l . At the time of dam c l o s u r e the r i v e r water was up t o 300 p e r c e n t s a t u r a t e d w i t h oxygen. W i t h i n f o u r weeks t h i s l e v e l f e l l t o s i x t e e n p e r c e n t s a t u r -a t i o n a t the s u r f a c e , and z e r o a t a depth of ten m e t e r s . In the subsequent months, the s u r f a c e oxygen l e v e l remained low and a t depths of f i v e and ten meters r a r e l y r e a c h e d ten p e r c e n t (Ewer, 1966). A l t h o u g h r e o x y g e n a t i o n o c c u r s both d i r e c t l y from the atmosphere, and from i n f l o w i n g w a t e r , i t i s u n l i k e l y t o keep pace w i t h the oxygen demand of d e c a y i n g v e g e t a t i o n . The i n i t i a l decay of v e g e t a t i o n i n r e s e r v o i r s makes them q u i t e u n l i k e n a t u r a l l a k e s . In a n a t u r a l l a k e , the n u t r i e n t l e v e l i s i n i t i a l l y l ow, but g r a d u a l l y i n c r e a s e s t h r o u g h g e o l o g -i c a l t i m e — t h e l a k e p r o g r e s s e s from an o l i g o t r o p h i c s t a t e t o 44 a e u t r o p h i c s t a t e . The r e s e r v o i r , however, has a v e r y h i g h i n i t i a l n u t r i e n t l e v e l brought on by the decay of submerged t e r r e s t r i a l o r g a n i c m a t t e r and the consequent r e l e a s e of " s t o r e d " phosphates and n i t r a t e s . L a t e r d i s c u s s i o n w i l l i n d i c a t e the e f f e c t of t h i s r i c h n u t r i e n t l o a d on the p o p u l -a t i o n s w i t h i n the r e s e r v o i r . The p r o g r e s s i o n of the r e s e r -v o i r i s o p p o s i t e t o t h a t o f the n a t u r a l l a k e ( a t l e a s t i n the s h o r t term, u n t i l a po s t s t a b i l i t y p e r i o d i s r e a c h e d ) , and the n u t r i e n t l e v e l g r a d u a l l y f a l l s as the o r g a n i c m a t e r i a l on the r e s e r v o i r bottom d e c a y s , and the n u t r i e n t s pass down-stream from the dam. The e u t r o p h i c s t a t e o f a newly formed r e s e r v o i r may be s t r e n g t h e n e d by t h e r m a l s t r a t i f i c a t i o n o f water. As noted p r e v i o u s l y , a t h e r m o c l i n e i s l i k e l y t o de v e l o p i n any l a r g e l a k e . The upper l a y e r or e p i l i m n i o o has c o n t a c t w i t h the atmosphere, and t h e r e f o r e m a i n t a i n s a h i g h l e v e l o f d i s s o l -ved oxygen. However, t h e r e i s l i t t l e m i x i n g of the e p i l i m -n i o n and the h y p o l i m n i o n . Thus, as the oxygen i n the hypo-l i m n i o n i s e x h a u s t e d by d e c a y i n g o r g a n i c m a t t e r , t h e r e i s no s u p p l y t o r e p l a c e i t , e x cept i n some c a s e s the r e l a t i v e l y minor s u p p l y from the i n f l o w i n g r i v e r . Only d u r i n g the p e r i o d i n which the r e s e r v o i r water o v e r t u r n s and mixes i s t h e r e o p p o r t u n i t y f o r r e s t o r a t i o n of the oxygen l e v e l i n the h y p o l i m n i o n . 45 The K a r i b a R e s e r v o i r on the Zambezi R i v e r p r o v i d e s an example of h y p o l i m n i o n oxygen e x h a u s t i o n d u r i n g the a n n u a l p e r i o d of s t r a t i f i c a t i o n . When the r e s e r v o i r reached i t s maximum d e p t h , the upper 90 f o o t l a y e r warmed d u r i n g the sum-mer months, and t h e r e was l i t t l e m i x i n g w i t h the water below t h i s l e v e l . Oxygen d e p l e t i o n f o l l o w e d s t r a t i f i c a t i o n and the l o w e r water remained d e v o i d of oxygen u n t i l the l a k e o v e r t u r n e d d u r i n g the c o o l p e r i o d i n J u l y and August, The s i t u a t i o n r e p e a t s i t s e l f a n n u a l l y , however, as the mass of d e c a y i n g o r g a n i c matter i s d e c r e a s i n g the l e n g t h of the p e r -i o d w i t h no oxygen s h o r t e n s a n n u a l l y ( C o u l t e r , 1967). In the K a r i b a r e s e r v o i r , as i n many o t h e r s , d e c o m p o s i t i o n i n a s t a t e w i t h low d i s s o l v e d oxygen l e v e l s a l s o caused h i g h c o n c e n t r a t -i o n s of hydrogen s u l p h i d e . At the Brokopondo R e s e r v o i r i n Surinam, hydrogen s u l p h i d e c o n c e n t r a t i o n s b u i l t up t o such an e x t e n t t h a t the pH of the r i v e r water dropped from 6,5 t o 5,5 ( L e e n t v a a r , 1966), In c o n t r a s t w i t h most l a r g e r e s e r -v o i r s the e x p e c t e d s t r a t i f i c a t i o n o f water i n Lake V o l t a has never o c c u r r e d . A l t h o u g h t h e r e i s minor t e m p e r a t u r e l a y e r i n g and c o n s i d e r a b l e oxygen d e p l e t i o n , a t no time has t h e r e been i n d i c a t i o n of d i s t i n c t s t r a t i f i c a t i o n p r e v e n t i n g m i x i n g of top and bottom w a t e r s (Ewer, 1966). R e g a r d l e s s of the e x a c t c o u r s e of e v e n t s these t h r e e examples i n d i c a t e the normal t r e n d i n newly f i l l e d r e s e r v o i r s — a s i t u a t i o n i n which oxygen l e v e l s d e c l i n e , n u t r i e n t l e v e l s r i s e , and the e v o l u t i o n o f hydrogen s u l p h i d e l e a d s t o a d e c r e a s e i n the pH, or i n c r e a s e d 46 a c i d i t y of the l a k e and downstream r i v e r w a t e r s . The d e c o m p o s i t i o n of o r g a n i c m a t t e r i s not the o n l y f a c t o r which c o n t r i b u t e s t o the h i g h n u t r i e n t l e v e l s which are common t o r e s e r v o i r s . Even a f t e r d e c o m p o s i t i o n has ex h a u s t e d the s u p p l y of n u t r i e n t s which may e v o l v e from the r e s e r v o i r b a s i n , " ... f e r t i l i t y , w h i l e a t a lower l e v e l than the excep-t i o n a l l y h i g h i n i t i a l s t a g e s , may w e l l remain h i g h e r than would be the case i n comparable n a t u r a l w a t e r s , s i n c e i n f l o w i n g r i v e r s u s u a l l y b r i n g a g r e a t e r volume of w a t e r , and w i t h i t n u t r i e n t s i n t o man-made than i n t o n a t u r a l l a k e s u n l e s s the l a t t e r are of r e l a t i v e l y s m a l l s i z e " ( J a c k s o n , 1966, p. 5 9 ) . In comparison w i t h n a t u r a l l a k e s which may take decades or even c e n t u r i e s t o a c h i e v e i n f l o w e q u a l t o t h e i r volume,. man-made l a k e s a re g e n e r a l l y e x p e c t e d t o f i l l w i t h i n a few y e a r s a f t e r c l o s u r e of the dam. T h i s r e l a t i v e l y h i g h i n f l o w and t h r o u g h f l o w , c o u p l e d w i t h d e p o s i t i o n of n u t r i e n t b e a r i n g s i l t s , y i e l d s the p o t e n t i a l f o r a c o n t i n u i n g h i g h l e v e l of b i o l o g i c a l p r o d u c t i v i t y i n r e s e r v o i r s . E f f e c t s of c l e a r i n g r e s e r v o i r b a s i n s In the p l a n n i n g of l a r g e r e s e r v o i r s , c o n s i d e r a t i o n i s u s u a l l y g i v e n t o c l e a r i n g of the b a s i n which i s to c o n t a i n the impounded w a t e r s . R a t i o n a l e f o r t h i s p r o c e d u r e u s u a l l y stems from a e s t h e t i c r e a s o n s , or the d e s i r e t o c r e a t e a r e a s s u i t a b l e f o r n a v i g a t i o n or f i s h i n g w i t h o u t the snagging of 47 l i n e s or n e t s . The c l e a r i n g of v e g e t a t i o n may a l s o have more d i r e c t b i o l o g i c a l i m p l i c a t i o n s . Commonly, where c l e a r i n g i s c a r r i e d o u t , a good d e a l o f the o r g a n i c m a t e r i a l w i l l be burned w i t h i n the b a s i n . The ash l e f t from t h i s p r o c e s s w i l l have the e f f e c t of c o n s i d e r a b l y i n c r e a s i n g i n i t i a l n u t r i e n t l e v e l s as i t i s more s o l u b l e and r e q u i r e s l e s s d e c o m p o s i t i o n than would the m a t e r i a l from which i t was d e r i v e d . The e f f e c t of f a i l i n g t o c l B a r a r e s e r v o i r b a s i n may be h i g h l y v a r i a b l e depending on the topography of the b a s i n , and the v e g e t a t i o n b e i n g i n u n d a t e d . In a s t e e p s i d e d b a s i n , a l l v e g e t a t i o n e x c e p t t h a t around the edges w i l l be d e e p l y sub-merged and w i l l have l i t t l e e f f e c t on water c i r c u l a t i o n w i t h -i n the r e s e r v o i r . A r e l a t i v e l y s h a l l o w r e s e r v o i r such as Lake V o l t a may a l s o be f i l l e d w i t h a m i n i m a l amount of c l e a r i n g . Here, the s p a r s e savanna v e g e t a t i o n w i t h i n much of the impoundment a r e a w i l l c r e a t e few p roblems. C l e a r i n g of more e x t e n s i v e v e g e t a t i o n a l o n g some of the p e r i p h e r y can now be a c c o m p l i s h e d d u r i n g draw-down p e r i o d s . At the Broko-pondo R e s e r v o i r , however, f a i l u r e t o c l e a r v e g e t a t i o n has had a v e r y d e f i n i t e e f f e c t . C i r c u l a t i o n of water t h r o u g h the drowned v e g e t a t i o n i s m i n i m a l and the l a k e has r a p i d l y t u r n e d i n t o a l a r g e swampy a r e a , w i t h s t a g n a n t water o r g a n -isms and e x t e n s i v e growths of a l g a l mats and duckweed ( L e e n t v a a r , 1966), / / 48 P r e i n u n d a t i o n l a n d c l e a r i n g around the s h o r e s of Lake K a r i b a brought u n a n t i c i p a t e d b e n e f i t s soon a f t e r the dam became o p e r a t i o n a l . A water weed, S a l v i n i a a u r i c u l a t a , grew a t a v e r y r a p i d and c o m p l e t e l y unexpected speed w h i l e the r e s e r v o i r was f i l l i n g . D u r i n g t h i s p e r i o d the water was h e l d r e l a t i v e l y s t a b l e by submerged v e g e t a t i o n , but as the water r e a c h e d i t s maximum l e v e l the c l e a r e d l a n d became i n u n d a t e d . Winds and wind c r e a t e d c u r r e n t s and waves were then a b l e t o blow the S a l v i n i a around the l a k e and the motion broke up many of the weed masses, s i g n i f i c a n t l y r e d u c i n g the problems which they had c r e a t e d . Faced by the u s u a l s i t u a t i o n i n which complete c l e a r i n g of a r e s e r v o i r bed would be p r o h i b i t i v e l y e x p e n s i v e , a u t h o r i t -i e s may p l a n t h e i r a c t i o n t o maximize the e f f e c t i v e n e s s of a p a r t i a l c l e a r i n g . I f b i o l o g i c a l p r o d u c t i v i t y of a r e s e r -v o i r i s c o n s i d e r e d t o be of im p o r t a n c e i n the development of l a k e f i s h e r i e s , but o n l y s m a l l amounts o f c l e a r i n g a re pos-s i b l e , the upper r e a c h e s of the water might b e s t be c l e a r e d . Here the water w i l l be s h a l l o w and p h o t o s y n t h e s i s may be ex p e c t e d t o oc c u r r i g h t t o the bottom ( J a c k s o n , 1966). C l e a r -i n g o f the a r e a s around r i v e r mouths w i l l a l s o prove t o be advan t a g e o u s , as here the g r e a t e s t e f f e c t of d i s s o l v e d n u t r i e n t s c a r r i e d i n the i n f l o w i n g water w i l l be r e a l i z e d . Other c l e a r i n g may be i m p o r t a n t to f a c i l i t a t e n a v i g a t i o n and f o r a e s t h e t i c p u r p o s e s , A comprehensive p l a n f o r c l e a r i n g i s 49 n e c e s s a r y t o ensure the d e s i r e d e f f e c t a t both h i g h water and draw-down. C l e a r i n g a f t e r i n u n d a t i o n may prove to be a : d i f -f i c u l t and e x p e n s i v e u n d e r t a k i n g . The e f f e c t s of s i l t i n g As d i s c u s s e d p r e v i o u s l y , the c o n s t r u c t i o n of a dam and f i l l i n g o f a r e s e r v o i r changes the normal p a t t e r n s of s i l t t r a n s p o r t and d e p o s i t i o n a l o n g a w a t e r c o u r s e . Both w i t h i n the r e s e r v o i r and downstream from the dam, the slowed f l o w of water l a c k s s u f f i c i e n t energy t o keep the s i l t i n s u s p e n s i o n . D e p o s i t i o n of t h i s s i l t may cause b i o l o g i c a l p r o b l e m s . On the M i s s i s s i p p i , w i t h t w e n t y - s i x dams between Minnea-p o l i s and S t . L o u i s , " ... the f l o w of the water has become so slow t h a t i t can c a r r y i n s u s p e n s i o n o n l y the v e r y f i n e s t s i l t and c o l l o i d a l p a r t i c l e s . A l l the r e s t s e t t l e s , some of i t on the mussel beds." ( B a r d a c h , 1964, p. 105). The c h o k i n g e f f e c t on the mussels i s o b v i o u s . The M i s s i s s i p p i has a l s o s u f f e r e d a d e c l i n e i n numbers of p a d d l e f i s h . T h i s i s " ... a t t r i b u t e d m a i n l y t o the b u i l d i n g of dams on the upper r i v e r ; t h e s e have meant more s i l t and fewer sand and g r a v e l bottoms which a r e the a n i m a l ' s p r e f e r r e d spawning s i t e s . " ( B a r d a c h , 1964, p. 113), E x c e s s i v e s i l t a t i o n a t the upper r e a c h e s of r e s e r v o i r s and around t h e i r s h o r e s , i n a d d i t i o n t o r e d u c i n g a n i m a l p o p u l a -t i o n s , may a l s o be e x p e c t e d t o choke water p l a n t s , r e s u l t i n g 50 i n a breakdown of the e v o l v i n g c h a i n of food d e pendencies between p l a n t s and a n i m a l s . I t s h o u l d be noted a t t h i s p o i n t t h a t s i l t i n g i s o f t e n an u n n e c e s s a r y problem " ... caused by s o i l e r o s i o n , i t s e l f a consequence of mismanagement of the (upstream) l a n d due t o bad a g r i c u l t u r a l p r a c t i c e s " ( J a c k s o n , 1966, p. 60) The e f f e c t s of draw-down Draw-down w i l l have an e f f e c t on organisms l i v i n g a l o n g the shore of a r e s e r v o i r , and below the h i g h water l e v e l . The e f f e c t can i n some i n s t a n c e s be q u i t e b e n e f i c i a l . Emer-gent p l a n t s ( r o o t e d below water but emerging i n t o the atmos-p h e r e , such as r e e d s and some g r a s s e s ) o f t e n pose a problem t o human a c t i v i t y a l o n g r e s e r v o i r s h o r e s . E l i m i n a t i o n t h r o u g h m e c h a n i c a l or c h e m i c a l means i s e x p e n s i v e , and may a d d i t i o n a l l y be somewhat r i s k y t o o t h e r o r g a n i s m s . R a p i d draw-down, however, can be used t o expose r o o t s and k i l l , a t l e a s t f o r a s h o r t t erm, the p l a n t p o p u l a t i o n s . By the same t e c h n i q u e spawning beds may be i n t e n t i o n a l l y exposed t o e l i m i n a t e f i s h s p e c i e s which are c o n s i d e r e d u n d e s i r a b l e . Games w i t h n a t u r e , such as the use o f draw-down t o e l i m i n a t e l i v i n g o r g a n i s m s , are complex and r i s k y , and must be preceded w i t h c a u t i o u s p l a n n i n g . F i s h s p e c i e s which are c o n s i d e r e d u n d e s i r a b l e may i n f a c t be an i m p o r t a n t l i n k i n the f o o d c h a i n f o r a v a l u a b l e f i s h s p e c i e s ; u n a e s t h e t i c water " g r a s s e s " and r e e d s may s h e l t e r communities of p l a n k t o n i c and o t h e r / 51 organisms which a r s c r i t i c a l i n food c h a i n s . Draw-down, such as t h a t accompanying power g e n e r a t i o n i n a low r i v e r f l o w p e r i o d , may be a u s e f u l means of b i o l o g i c a l c o n t r o l , but i t a l s o has the p o t e n t i a l t o worsen a l r e a d y t r o u b l e d s i t u a t i o n s , Weed growth i n r e s e r v o i r s High n u t r i e n t l e v e l s which are common i n the e v o l u t i o n of r e s e r v o i r s p r o v i d e an i d e a l environment f o r growth of water p l a n t s . Though t h e r e are few s p e c i e s of f l o a t i n g v a s -c u l a r p l a n t s , t h e i r p r e s e nce i n t r o p i c a l r e s e r v o i r s has c r e a t e d a number of unexpected p r o b l e m s . Temperate r e s e r -v o i r s have been a f f e c t e d t o a l e s s e r e x t e n t , as f l o a t i n g v a s c u l a r p l a n t s are not adapted t o growth i n c o o l c l i m a t e s . Three p l a n t s p e c i e s have been the cause of most t r o p i c a l r e s e r v o i r weed p r o b l e m s ! E i c h h o r n i a . c r a s s i p e s ( w a t e r hyac-i n t h ) , S a l v i n i a a u r i c u l a t a ( w a t e r f e r n ) , and P i s t a  s t r a t i o t e s ( w a t e r l e t t u c e ) . Lake K a r i b a has s u f f e r e d from the g r e a t e s t growth of water p l a n t s . Soon a f t e r impoundment began, S a l v i n i a was n o t i c e d f l o a t i n g i n the water and w i t h i n t h r e e y e a r s the growth c o v e r e d a r e a s t o t a l l i n g 250 square m i l e s ( C o u l t e r , 1967). As the growth of S a l v i n i a was u n e x p e c t e d , no measures had been p l a n n e d f o r i t s c o n t r o l . "However, once the c l e a r e d s e c t i o n s were f l o o d e d 52 the mats of weeds soon broke up under wave and wind a c t i o n , and today the i n f e c t e d a r e a s are c o n f i n e d t o those r e g i o n s where bush c l e a r i n g was not c a r r i e d o u t , where semi-submerged t r e e s a r e abundant and i n most r i v e r e s t u a r i e s and b a y s . " ( H a r d i n g , 1966, p. 1 8 ) . Even though the s i t u a t i o n was thus r e l i e v e d a t Lake K a r i b a , S a l v i n i a and P i s t a s t i l l grow i n the r e s e r v o i r and p r e s e n t problems i n the i n t e n d e d r e s e r v o i r o p e r a t i o n s . At l e a s t minor weed growths have been documented w i t h i n or downstream from most t r o p i c a l r e s e r v o i r s . In the J e b e l A u l i y a R e s e r v o i r on the White N i l e , E i c h h o r n i a grows e x t e n s i v e l y and a major program has been r e q u i r e d t o p r e v e n t i t s s p r e a d downstream i n t o Lake N a s s e r , At the Brokopondo r e s e r v o i r i n Surinam, E i c h h o r n i a has s p r e a d r a p i d l y t h r o u g h the s h a l l o w , a l m o s t s t a g n a n t r e s e r v o i r . With the o u t b r e a k of S a l v i n i a a t Lake K a r i b a t h e r e was c o n s i d e r a b l e f e a r t h a t the weed would a l s o i n f e c t Lake V o l t a , however t h i s has not been the c a s e . In f a c t , S a l v i n i a has not posed a problem i n any r e s e r v o i r e x c e p t K a r i b a ; i t i s a good example of a new s p e c i e s f i n d i n g an empty n i c h e i n the ecosystem and growing e x p l o s i v e l y i n i d e a l c o n d i t i o n s and w i t h a l a c k of organisms dependent on the s p e c i e s f o r f o o d . In Lake V o l t a , t h e r e has been some, though not e x t e n s i v e growth of P i s t a . The dam h a s , however, brought about p l a n t growth downstream of the r e s e r v o i r . R a p i d development of Potamoqeton o c t a n d r u s and V a l l i s n e r i a  a e t h i o p i c a , both submerged s p e c i e s , i s c o n s i d e r e d to be due t o a l a c k of r i v e r bed s c o u r i n g by a n n u a l f l o o d waters ( H a l l and P o p l e , 1968). 53 The growth of water p l a n t s i n r e s e r v o i r s can pose a v a r i e t y of problems» (1) they may be blown i n t o c h a n n e l s b l o c k i n g i n f l o w i n g w a t e r , or b e i n g sucked i n t o o u t f l o w s t r u c t u r e s and t u r b i n e s , ( 2 ) they may impede or p r e v e n t nav-i g a t i o n , (3) they can b r i n g about d e o x y g e n a t i o n and cause f i s h l o s s e s , (4) they can s u b s t a n t i a l l y reduce r e s e r v o i r volume, and (5) they c a n , t h r o u g h e v a p o t r a n s p i r a t i o n , cause a s u b s t a n t i a l i n c r e a s e i n e v a p o r a t i o n l o s s e s . On the f i n a l p o i n t , one r e s e a r c h e r i s c i t e d as s t a t i n g t h a t E i c h h o r n i a  c r a s s i p e s can b r i n g about a s i x - f o l d i n c r e a s e i n evapor-a t i o n ( L i t t l e , 1 966), I f t h i s i s a c t u a l l y the c a s e , e x t e n -s i v e growth of t h i s weed c o u l d p r e v e n t the o p e r a t i o n of some r e s e r v o i r s , f o r e v a p o t r a n s p i r a t i o n would e q u a l i n f l o w . P l a n t growth i n temperate r e s e r v o i r s may be c o n s i d e r e d a l e s s s e r i o u s problem than i n t r o p i c a l r e s e r v o i r s . Few f l o a t i n g v a s c u l a r s p e c i e s a re found i n temperate a r e a s , so growth i s l i m i t e d t o the p e r i p h e r y of the r e s e r v o i r where l i g h t p e n e t r a t i o n t o the bottom i s p o s s i b l e . A depth of 30 f e e t i s the maximum from which submerged p l a n t s are l i k e l y t o grow. Emergent p l a n t s w i l l grow even c l o s e r t o the s h o r e . Though they can be u n a e s t h e t i c and d e l e t e r i o u s t o some human shore u s e s , they p r o v i d e a h a b i t a t f o r many of the m i c r o - o r g a n i s m s upon which r e s e r v o i r fauna w i l l be dependent f o r f o o d . 54 Shore v e g e t a t i o n around r e s e r v o i r s In a d d i t i o n t o grouith of mater weeds w i t h i n a r e s e r -v o i r , changes may be e x p e c t e d i n p l a n t , s p e c i e s around the edge of a r e s e r v o i r and i n some ca s e s downstream from the dam. In the p r o x i m i t y o f the r e s e r v o i r s h o r e , the ground water t a b l e i s l i k e l y . t o r i s e r e l a t i v e t o i t s o l d p o s i t i o n , and r a t h e r than e x p e r i e n c e s e a s o n a l f l u c t u a t i o n s , i t s l e v e l w i l l r e l a t e t o the r e s e r v o i r l e v e l . V e g e t a t i o n s i m i l a r t o t h a t around the s h o r e s of n a t u r a l l a k e s i s t o be e x p e c t e d . In a r e a s w i t h minor r e l i e f , swamp and marsh development i s l i k e l y , w h i l e i n w e l l d r a i n e d a r e a s w i t h g r e a t e r r e l i e f , t h e r e w i l l be l i t t l e change, e x c e p t a t the immediate edge of the w a t e r . M o d e r a t i o n of t e m p e r a t u r e extremes w i l l be r e f -l e c t e d by the v e g e t a t i o n around a r e s e r v o i r , p r o v i d i n g the m o d e r a t i o n i s m a i n t a i n e d year round by i c e - f r e e c o n d i t i o n s . I f c r e a t i o n of the r e s e r v o i r r e s u l t s i n c l i m a t i c changes, the v e g e t a t i o n t h r o u g h o u t the a r e a s a f f e c t e d w i l l undergo a l o n g term change. The c o n t r o l l e d f l o w of the r i v e r w i l l cause v e g e t a t i o n changes downstream from a dam. S e a s o n a l f l u c t u a t i o n s i n the water t a b l e w i l l be reduced or e l i m i n a t e d and t h e r e w i l l u s u a l l y be a net r e d u c t i o n i n s o i l m o i s t u r e c o n t e n t a l o n g the banks ( L a g l e r , 1971), In e s t u a r i n e a r e a s the c o n t r o l l e d f l o w of w a t e r s has caused the d r y i n g of marshes. Sedge 55 marshes i n the Peace-Athabasca d e l t a , f o r example, are b e i n g e f f e c t i v e l y d r a i n e d , and dense w i l l o w t h i c k e t s are l i k e l y t o take t h e i r p l a c e ( S c h u l t z , e t a l , , 1970). T h i s u n a n t i c i p a t e d e f f e c t of the W i l l i s t o n R e s e r v o i r w i l l s e r i o u s l y reduce the f o r a g i n g a r e a f o r b i s o n of Wood B u f f a l o N a t i o n a l P a r k . EFFECTS ON THE FAUNA OF THE RESERVOIR AREA I n s e c t p o p u l a t i o n s The impounding of l a r g e q u a n t i t i e s of water i n r e s e r v o i r s p r o v i d e s an i d e a l b r e e d i n g h a b i t a t f o r a v a r i e t y of i n s e c t s , both i n the swampy shore a r e a s , and i n the m o d i f i e d , reduced f l o w downstream from the dam. Often these i n s e c t s d e v e l o p t o become c a r r i e r s of s e r i o u s d i s e a s e as d i s c u s s e d i n the i m m e d i a t e l y f o l l o w i n g s e c t i o n . Examples o f i n s e c t p o p u l a t i o n changes can be documented f o r most r e s e r v o i r s . The J e b e l A u l i y a R e s e r v o i r , b u i l t upstream from Khartoum on the White N i l 8 i n 1937, p r o v i d e d an environment s u i t a b l e f o r i n s e c t b r e e d i n g w i t h i n the r e s e r -v o i r and a l s o downstream from the dam ( L e w i s , 1966), Draw-down of the r e s e r v o i r r e s u l t s i n the f o r m a t i o n of p o o l s s urrounded by sand b a r s , w h i c h p r o v i d e a h a b i t a t f o r l a r v a e of the m o s q u i t e , Anopheles qambiae, which i s the c a r r i e r o f human m a l a r i a . Downstream from the dam, f l o a t i n g r a f t s of 56 papyrus become s t r a n d e d a l o n g the r i v e r banks and s u p p o r t an e c o l o g i c a l s u c c e s s i o n l e a d i n g t o the growth of Anopheles  p h a r o e n s i s , a l e s s dangerous s p e c i e s of m o s q u i t o . Changes i n f i s h p o p u l a t i o n s have l e d t o i n c r e a s e s i n i n s e c t p o p u l a t i o n s . Near A s t r a k h a n , a t the mouth of the V o l g a R i v e r , the d e c l i n i n g l e v e l of the C a s p i a n Sea has e l i m i n a t e d spawning grounds f o r the b e l y i amur, a f i s h which f e e d s on m o s q u i t o e s . With the i n c r e a s e i n swamp a r e a and d e c r e a s e i n p o p u l a t i o n s of b e l y i amur, the mosquito p o p u l a -t i o n has grown and begun t o c a r r y m a l a r i a (Goldman, 1970). A l t h o u g h not s t r i c t l y w i t h i n the p a r a m e t e r s of a d i s -c u s s i o n of r e s e r v o i r s , the c l o s i n g o f f of the Dutch Z u i d e r Zee by dykes i n 1935 l e d t o an i n t e r e s t i n g i n s e c t p o p u l a t i o n i n c r e a s e . Without n a t u r a l f i s h p r e d a t i o n on the l a r v a e , midges of the T e n d i p e s group rose i n c l o u d s from the m o i s t swampy a r e a s which were s t i l l d r y i n g i n 1938 ( V a a s , 1966), T h i s s i t u a t i o n f o r t u n a t e l y has not r e p e a t e d i t s e l f , as the r e c l a i m e d l a n d has become too dry t o s u p p o r t the midge l a r v a e . The e f f e c t o f r e s e r v o i r s on the c a r r i e r s of d i s e a s e R e s e r v o i r s f r e q u e n t l y c r e a t e h a b i t a t s s u i t a b l e f o r the growth of c a r r i e r s of d i s e a s e s . These d i s e a s e v e c t o r s l e a d 57 t o c o n s i d e r a b l e l o s s of l i v e s t o c k , economic h a r d s h i p , and human s u f f e r i n g i f they are not q u i c k l y brought under c o n t r o l . The p r i n c i p a l d i s e a s e s c a r r i e d from r e s e r v o i r c o n d i t i o n s i n c l u d e b i l h a r z i a , m a l a r i a , t r y p a n o s o m i a s i s ( s l e e p i n g s i c k n e s s ) , and o c h o c e r i a s i s ( r i v e r b l i n d n e s s ) . In a d d i t i o n t o growth of p o p u l a t i o n s of d i s e a s e v e c t o r s , p o p u l a t i o n s of i n s e c t s may grow which cause e p i d e m i c a l l e r g i e s i n human p o p u l a t i o n s , or which a re a g e n e r a l n u i s a n c e . The problem of r e s e r v o i r s l e a d i n g t o growth of d i s e a s e v e c t o r s and i n s e c t p e s t s i s g r e a t e s t i n the t r o p i c s . The problem of m a l a r i a has been i n c r e a s e d i n the U n i t e d Arab R e p u b l i c by the b u i l d i n g of dams. In Sudan, Anopheles  gambiae, the v e c t o r of m a l a r i a , breed i n r e s e r v o i r s and i r r i g a t i o n c a n a l s ( L e w i s , 1966). M a l a r i a has a l s o become a problem around the s t i l l f o r m i n g Lake Nasser (Dorcey e t a l . , 1972). Though the mosquito can be brought under c o n t r o l by s p r a y i n g of b r e e d i n g a r e a s w i t h p e s t i c i d e s or o i l s , such measures p r e s e n t u n a n t i c i p a t e d c o s t s and h a r m f u l s i d e e f f e c t s . With the c r e a t i o n of Lake K a r i b a , t h e r e has been a p r o b -lem w i t h t r y p a n o s o m i a s i s , which i s c a r r i e d by the t s e t s e f l y . P a r a s i t i c b l o o d trypanosomes have i n f e c t e d the n a t i v e s ' c a t t l e , c a u s i n g s e r i o u s d i s e a s e and p r e s e n t i n g e x t r a problems f o r the groups o f pe o p l e d i s l o c a t e d from homes w i t h i n the r e s e r v o i r b a s i n ( H e n k i n , 1969). / / 58 A l t h o u g h p r o p a g a t i o n of the b l a c k f l y , S i m u l i u m , the c a r -r i e r of o c h o c e r i a s i s , i s not promoted by the e x i s t e n c e of r e s e r v o i r s , the f l y has p r e s e n t e d problems d u r i n g c o n s t r u c t i o n of t r o p i c a l r e s e r v o i r s . The f l y r e q u i r e s f a s t f l o w i n g water f o r egg and l a r v a l s t a g e s , and i d e a l b r e e d i n g s i t e s are o f t e n i n the v i c i n i t y of dam c o n s t r u c t i o n p r o j e c t s . B l i n d -ness i s not always a consequence of b i t e s by the f l y : (Warmann, 1969), but u n d e r s t a n d a b l y the p o s s i b i l t i y p r o v o k e s f e a r amongst c o n s t r u c t i o n w o r k e r s , and i n c ases t h i s f e a r has l e d t o c o n s t r u c t i o n slowdowns. In any c a s e , the comple-t i o n of dams and s l o w i n g of waters i n r e s e r v o i r s i s an e f -f e c t i v e d e t e r r e n t t o f u r t h e r b r e e d i n g of the f l i e s , e x c e p t i n c o n f i n e d l o c a t i o n s such as s p i l l w a y s , which can be c a r e f u l l y watched f o r i n f e c t i o n . E l i m i n a t i o n of o c h o c e r i a -s i s s h o u l d be a g o a l i n the c o n s t r u c t i o n of any r e s e r v o i r s i n a r e a s where the d i s e a s e i s p r e v a l e n t , The g r e a t e s t d i s e a s e h a z a r d i n t r o d u c e d by r e s e r v o i r s i s s c h i s t o s o m i a s i s or b i l h a r z i a . The d i s e a s e i s caused by a Trematode b l o o d f l u k e , h o s t e d i n an immature s t a g e by s n a i l s which f i n d a h a b i t a t i n slow or s t a b l e water. R e s e r v o i r s are an i d e a l b r e e d i n g ground f o r the s n a i l h o s t s , as compared t o the n a t u r a l f l o w i n g r i v e r . Two forms of the d i s e a s e are p r e v a l e n t , the u r i n a r y S c h i s t o s o m a haematobium, and the more dangerous i n t e s t i n a l S c h i s t o s o m a mansoni ( H e n k i n , 1969). E x i s t e n c e of water weeds such as S a l v i n i a f u r t h e r improves 59 the h a b i t a t f o r s n a i l s , and i n c r e a s e s the h a z a r d of i n f e c t i o n ( H i r a , 1969). The e f f e c t of s c h i s t o s o m i a s i s on human p o p u l a t i o n s i s d i s c u s s e d i n the s e c t i o n d e a l i n g w i t h human and c u l t u r a l e f f e c t s . The Aswan High Dam has l e d t o i n c r e a s e d p o p u l a t i o n s of the f l y , T a n y t a r s u s , which b r i n g s on an a s t h m a t i c a l l e r g y i n l a r g e p o r t i o n s of the p o p u l a t i o n . The problem became so ac u t e a t Wadi H a i f a , a town near the shore of Lake Nasser a t the border between Egypt and Sudan, t h a t an asthma camp had to be b u i l t i n the d e s e r t , and r e l o c a t i o n of the town was c o n s i d e r e d . The problem of d i s e a s e s born from newly c r e a t e d r e s e r -v o i r s i s f a r from b e i n g s o l v e d . Even i f massive i n p u t s of b i o c i d e s were s u c c e s s f u l i n c o n t r o l l i n g or e l i m i n a t i n g vec-t o r s of d i s e a s e from r e s e r v o i r s (and as yet t h i s i s not the c a s e ) , the s i d e e f f e c t s of such measures c o u l d outweigh the b e n e f i t s . L u c k i l y , temperate r e s e r v o i r s have not l e d t o the development of s e r i o u s human d i s e a s e v e c t o r s . On the o t h e r hand, they must be r e c o g n i z e d as p o t e n t i a l b r e e d i n g s i t e s f o r l i v e s t o c k p a r a s i t e s and d i s e a s e v e c t o r s , and i n s e c t s which cause c o n s i d e r a b l e human n u i s a n c e . C o n t i n u i n g r e s e a r c h i s e s s e n t i a l t o reduce d i s e a s e and i n s e c t problems brought about by r e s e r v o i r c o n s t r u c t i o n i n a l l c l i m a t i c a r e a s . 60 The e f f e c t s on w i l d l i f e The f i l l i n g and e x i s t e n c e of a r e s e r v o i r can have wide r a n g i n g i m p a c t s on w i l d l i f e . D u r i n g the f i l l i n g of r e s e r -v o i r s the most sudden e f f e c t s o c c u r , as a n i m a l s are s t r a n d e d on h i g h p o r t i o n s of ground w i t h i n the r e s e r v o i r a r e a . S t r a n d -i n g of a n i m a l s by the r i s i n g w aters of Lake K a r i b a a r o u s e d w o r l d wide a t t e n t i o n , and w i t h the h e l p of v o l u n t a r y f u n d i n g from a l l over the w o r l d a l a s t minute r e s c u e o p e r a t i o n was launc h e d i n which some t h r e e - t h o u s a n d a n i m a l s i n c l u d i n g b i r d s , r e p t i l e s and m i s c e l l a n e o u s mammals were t r a n s p o r t e d from i s l a n d s t o the r e s e r v o i r edge ( C l e m e n t s , 1959). 8y c o n t r a s t , t h e r e appear t o have been few a n i m a l s endangered a t Lake V o l t a , even though r e s c u e p r o c e d u r e s were p o o r l y p l a n n e d and e x e c u t e d ( A s i b e y , 1969). Of g r e a t e r l o n g term s i g n i f i c a n c e than the i n i t i a l e f f e c t of r i s i n g r e s e r v o i r w a t e r s , i s the change i n a n i m a l h a b i t a t s brought on by the c o n s t r u c t i o n of dams and the f i l l i n g of r e s e r v o i r s . I n u n d a t i o n of l i m i t e d g r a z i n g a r e a s may t h r e a t e n a n i m a l s p e c i e s , or downstream changes i n hab-i t a t may reduce food s u p p l y . Sedge marshes a t the Peace-Athabasca d e l t a are d r y i n g as a consequence of reduced f l o w i n the Peace R i v e r , These marshes are c r i t i c a l f o r the f o r a g i n g o f b i s o n , and p r o v i d e a h a b i t a t f o r l a r g e p o p u l a t i o n s of muskrat which have p r o v i d e d t r a p p i n g income f o r n a t i v e / / 6 1 p e o p l 8 . F u r t h e r changes may come about i n t h i s d e l t a a r e a as the l a k e s dry and t h e r e i s a r e d u c t i o n of the a r e a s u i t -a b l e f o r m i g r a t o r y b i r d s and v a r i o u s o t h e r f u r b e a r i n g a n i m a l s ( S c h u l t z e t a l , , 1970). C a r e f u l c o n s i d e r a t i o n must be g i v e n t o w i l d l i f e h a b i t a t s i n the p l a n n i n g of r e s e r v o i r p r o j e c t s . I t i s not enough t o s i m p l y assume t h a t a n i m a l s w i l l go away from the r e s e r v o i r a r e a and t h a t a l l w i l l be w e l l . For many s p e c i e s a p a r t i c -u l a r h a b i t a t a t a p a r t i c u l a r time of the year i s c r i t i c a l , and i t s removal may e l i m i n a t e the s p e c i e s p o p u l a t i o n from the a r e a . EFFECTS ON ANADROMOUS FISH Upstream m i g r a t i o n of f i s h The damming of l a r g e r i v e r s has r e s u l t e d i n s e r i o u s p o p u l a t i o n d e c l i n e s of anadromous or m i g r a t o r y f i s h s p e c i e s . For the f i s h , c o n s t r u c t i o n of a r e s e r v o i r poses a v a r i e t y of t h r e a t s t o both upstream and downstream m i g r a t i o n . The dam i t s e l f i s , of c o u r s e , a major b a r r i e r t o the f i s h . However, i n the upstream m i g r a t i o n , problems may a r i s e soon a f t e r e n t r y i n t o the r i v e r . The f i r s t change a m i g r a t o r y f i s h i s l i k e l y t o e x p e r i e n c e because of an upstream dam, i s i n the t e m p e r a t u r e of the r i v e r water. D u r i n g spawning season the water i n a r i v e r may be a t a c o n s i d e r a b l y h i g h e r t e m p e r a t u r e than would be the case i f the r e s e r v o i r was not p r e s e n t , M i g r a t o r y s p e c -i e s a l o n g the N o r t h American P a c i f i c c o a s t are g e n e r a l l y c a p a b l e of w i t h s t a n d i n g t e m p e r a t u r e s under 68 degrees Fah-r e n h e i t , however, a f t e r s t o r a g e i n a r e s e r v o i r t h i s temp-e r a t u r e may be exceeded, A minor temperature change may be a l l t h a t i s r e q u i r e d t o change a m a r g i n a l environment i n t o a l e t h a l one (Hoar, 1956), Some f i s h may be e x p e c t e d t o spawn between the e s t u a r -i n e a r e a and the f i r s t dam on a l a r g e r i v e r . Even i f temp-e r a t u r e m o d i f i c a t i o n does not pose a t h r e a t , o t h e r f a c t o r s may p r e v e n t normal development of the eggs. D i s c h a r g e of r e s e r v o i r waters from below the t h e r m o c l i n e may b r i n g the d i s s o l v e d oxygen c o n t e n t below the minimum r e q u i r e d f o r development (Hoar, 1956), In the autumn, when many salmon spawn, h y p o l i m n i o n oxygen c o n t e n t i s l i k e l y t o be near i t s minimum a n n u a l l e v e l , S i l t a t i o n of spawning grounds below r e s e r v o i r s may a l s o t h r e a t e n development of eggs. Water l e v e l s are n a t u r a l l y low i n the autumn, but dam s t o r a g e can reduce l e v e l s f u r t h e r and the s l o w e r , lower volume downstream d i s c h a r g e w i l l lower c a p a c i t y f o r moving s i l t downstream and beyond spawning a r e a s . 63 The dam i s a major o b s t a c l e f o r f i s h . C u r r e n t p r a c t i c e i n N o r t h American and European p r o j e c t s i s c o n s t r u c t i o n of f i s h l a d d e r s through which the f i s h may proceed from downstream of the dam t o an e x i t w i t h i n the r e s e r v o i r . Placement of the e n t r a n c e of f i s h l a d d e r s i s a c r i t i c a l f a c t o r i n d e t e r m i n i n g t h e i r u s e f u l n e s s . F i s h a p p a r e n t l y p r e f e r t o head i n t o the s t r o n g e s t c u r r e n t . I f the water f l o w i n g from the l a d d e r does not a t t r a c t t h e i r a t t e n t i o n , t h e y w i l l c o n t i n u e upstream to the base of the dam. The s u c c e s s of f i s h l a d d e r s i s a l s o l i m i t e d by t h e i r h e i g h t , and f o r dams over about 1 0 0 f e e t i n h e i g h t , spawning s u c c e s s i s low. Once an anadromous f i s h i s s a f e l y w i t h i n the r e s e r v o i r t h e r e a re s t i l l h a z a r d s which may p r e v e n t spawning. C u r r e n t t h r o u g h the r e s e r v o i r can sweep f i s h over the dam or th r o u g h the t u r b i n e s , e v e n t s t h a t w i l l p r o b a b l y prove t o be too much of a s t r a i n f o r a f i s h which i s n e a r i n g the end of i t s l i f e . C a r e f u l placement of l a d d e r e x i t s s h o u l d m i n i m i z e the pos-s i b i l i t y of the f i s h b e i n g swept downstream. However, t o o g r e a t a c u r r e n t r e d u c t i o n a t the r e s e r v o i r e x i t of the f i s h l a d d e r w i l l c o n f u s e the f i s h , which i s dependent on c u r r e n t f o r n a v i g a t i o n . F u r t h e r , c i r c u l a r c u r r e n t s may oc c u r w i t h i n the r e s e r v o i r , l e a v i n g the f i s h swimming i n c i r c l e s , r a t h e r than through the l a k e . Delay w i t h i n the r e s e r v o i r may p r e v e n t spawning. C u m u l a t i v e d e l a y i n s e v e r a l r e s e r v o i r s i n c r e a s e s the p r o b a b i l i t y of spawning f a i l u r e . 1 64 A f i n a l h a z a r d t o spawning i s the i n u n d a t i o n of spawn-i n g beds under r e s e r v o i r w a t e r s . F i s h such as salmon are dependent on r a p i d water f l o w t o s u p p l y oxygen t o the eggs, so shore zones are of l i t t l e use f o r spawning. Spawning beds i n the main r i v e r may be l o s t f o r m i l e s upstream from the dam and the r e d u c t i o n of e f f e c t i v e l e n g t h of the t r i b -u t a r i e s w i l l l e a d t o c r o w d i n g . E f f o r t s t o m i n i m i z e the e f f e c t of dams on the spawning p a t t e r n of anadromous f i s h have been l e s s than a l t o g e t h e r s u c c e s s f u l . The e x p e r i e n c e g a i n e d i n a l a r g e number of * p r o j e c t s i s , however, l e a d i n g t o the d e s i g n of c o n s i d e r a b l y improved f a c i l i t i e s , f o r h a n d l i n g f i s h . Downstream m i g r a t i o n of f i s h Even a f t e r s u c c e s s f u l spawning and h a t c h i n g of f r y has come about i n r i v e r s b l o c k e d by dams, the young f i s h may enco u n t e r d i f f i c u l t i e s i n t h e i r j o u r n e y downstream. Two b a s i c problems e x i s t : passage of the f i s h t h r o u g h r e s e r v o i r s , and damage t o the f i s h as t h e y pass from r e s e r v o i r t o r i v e r , whether through t u r b i n e s or over s p i l l w a y s . The r e s e r v o i r l a k e p r e s e n t s a c o m p l e t e l y u n n a t u r a l s i t -u a t i o n f o r f i s h such as c h i n o o k salmon, which n o r m a l l y spawn below any l a k e s on a r i v e r . As the young f i s h e n t e r the 65 r e s e r v o i r and c u r r e n t s l o w s , they may d e l a y t h e i r downstream t r i p , s p e n d i n g s e v e r a l weeks f e e d i n g i n the r e s e r v o i r , When they c o n t i n u e , the r e s e r v o i r waters w i l l have warmed, and b e i n g a c o l d water f i s h , t h ey are l i k e l y t o head upstream t o the r e s e r v o i r i n f l o w , which w i l l be c o l d e r r i v e r water ( B a r d a c h , 1964), Such c o n f u s i o n may c a n c e l the m i g r a t o r y urge, and the f i s h w i l l l i v e a m o d i f i e d l i f e c y c l e i n the r e s e r v o i r . P a s s i n g through or over a dam c r e a t e s a h a z a r d i n the downstream movement of a l l m i g r a t o r y f i s h . R i d i n g the water over a dam s p i l l w a y may cause a young salmon " ... t o be s u b j e c t e d t o c o n s i d e r a b l e changes i n p r e s s u r e or ... a vacuum f o r a b r i e f p e r i o d . Water p a s s i n g over the s p i l l w a y of a dam may f a l l f r e e of the s p i l l w a y f a c e and produce a ' c a v i t a t i o n ' phenom-enon which a c t u a l l y amounts t o a l o c a l vacuum. Ha m i l t o n and Andrews c o n s i d e r c a v i t a t i o n the most i m p o r t a n t p o s s i b l e cause of i n j u r y t o downstream mig-r a n t salmon on s p i l l w a y s and i n t u r b i n e s . " (Hoar, 1956, p. 2 1 ) . The a l t e r n a t i v e t o passage over the s p i l l w a y i s p a s s i n g through the t u r b i n e s . Though the young f i s h may o b v i o u s l y s u f f e r from b r u i s i n g and a b r a s i o n , the t r i p i s not so dan-gerous as i t a t f i r s t sounds, f o r the t u r b i n e b l a d e s are w i d e l y spaced and the r o t a t i o n i s r e l a t i v e l y s l o w . S c o t t i s h e x p e r i m e n t s i n d i c a t e a m o r t a l i t y r a t e of ten t o twenty p e r c e n t i n t e s t s i t u a t i o n s w i t h a 170 f o o t head of water. The cumul-a t i v e e f f e c t of s u b j e c t i n g downstream m i g r a n t s t o a number of r e s e r v o i r s and dams must be r e c o g n i z e d ( P y e f i n c h , 1966). o 66 EFFECTS DOWNSTREAM FROM RESERVOIRS E f f e c t s r e s u l t i n g from the r e l e a s e of f o u l e d maters At v a r i o u s t i m e s of the year i t may be d e s i r a b l e t o exhaust water from below the t h e r m o c l i n e , f l u s h i n g sediments from the r e s e r v o i r bottom. T h i s p r o c e d u r e must be c a r e f u l l y c o n s i d e r e d , as the r e l e a s e of deoxygenated water may have h a r m f u l e f f e c t s on the downstream f l o r a and fauna ( J a c k s o n , 1966). The bottom waters are l i k e l y t o a l s o c o n t a i n concen-t r a t i o n s of hydrogen s u l p h i d e and o t h e r c h e m i c a l s which d e v e l o p a f t e r a n a e r o b i c c o n d i t i o n s o c c u r . E f f e c t s of the l o s s of downstream sediments F a i l u r e t o r e l e a s e sediments from a r e s e r v o i r may have s e v e r a l e f f e c t s on downstream b i o l o g y . These i n c l u d e the l a c k of s i l t which i s e s s e n t i a l i n m a i n t a i n i n g the f e r t i l -i t y of s o i l on the a l l u v i a l r i v e r banks, r e d u c t i o n i n n u t r i e n t l e v e l s , and changes i n the e s t u a r i n e e n v i r o n m e n t . L o s s of f r e s h s u p p l i e s of s i l t from r i v e r banks w i l l l e a d t o d e c l i n e i n s o i l f e r t i l i t y , e s p e c i a l l y i n l o c a t i o n s where a g r i c u l t u r e i s p r a c t i c e d on the a l l u v i a l f l a t s . A l o n g the N i l e R i v e r f e r t i l i z e r i s a l r e a d y r e q u i r e d because of the c a p t u r e of sediment behind the Aswan High Dam ( S t e r l i n g , 1971). 67 Even i n c a s e s where a l l u v i a l s o i l i s not c r o p p e d , reduced f e r t i l i t y may l e a d to changes i n v e g e t a t i o n a l o n g the r i v e r and w i t h i n the r i v e r c h a n n e l . These v e g e t a t i o n changes may be r e f l e c t e d by changes i n p o p u l a t i o n s of dependent a n i m a l s . F u r t h e r d i s c u s s i o n of the e f f e c t of l o w e r e d s i l t d e p o s i t i o n . downstream from dams i s found i n the f o l l o w i n g s e c t i o n s . E f f e c t of reduced f l o w s on downstream f i s h Reduced downstream f l o w r e s u l t i n g from the o p e r a t i o n of a dam may s e r i o u s l y reduce spawning a c t i v i t y of f i s h s p e c i e s which spawn i n l a k e s or e s t u a r i n e a r e a s . In the C a s p i a n Sea, which has dropped by 2,5 meters from damming and d i v e r -s i o n of i n f l o w i n g r i v e r s , the spawning a r e a s u i t a b l e f o r s t u r g e o n has been reduced i n a r e a by o n e - t h i r d (Goldman, 1970). T h i s f a c t o r , c o u p l e d w i t h o i l p o l l u t i o n , has brought a s i z e a b l e d e c l i n e i n the s t u r g e o n c a t c h and a drop i n c a v -i a r p r o d u c t i o n . The Peace-Athabasca d e l t a and Lake A t h a b a s c a are a l s o s u f f e r i n g from water s h o r t a g e , i n t h i s case caused by impoundment of water i n the W i l l i s t o n R e s e r v o i r . In the d e l t a a r e a p i k e spawning beds have been exposed i n a l l but the deepest c h a n n e l s , w h i l e a l o n g the l a k e s h o r e s the spawn-i n g beds of the c i s c o have been exposed f o r two c o n s e c u t i v e w i n t e r s . " . . . I t i s to be e x p e c t e d t h a t the c o m m e r c i a l f i s h e r y i n Lake Athabasca w i l l c o l l a p s e w i t h i n t h r e e t o f i v e y e a r s as r e c r u i t m e n t to the h a r v e s t a b l e f i s h p o p u l a t i o n s / / 68 of w a l l e y e , p i k e , and l a k e t r o u t d e c l i n e s , and as s t o c k s of c i s c o are e l i m i n a t e d as the b a s i c food s u p p l y f o r the c a r n i v o r o u s s p e c i e s l i s t e d above." ( S c h u l t z , e t a l . , 1970, p. 1 0 ) . A l t h o u g h the c r e a t i o n of a r e s e r v o i r may b r i n g i n t o e x i s t -ence a h a b i t a t s u i t a b l e f o r the e x i s t e n c e of d i f f e r e n t f i s h s p e c i e s t o those i n the r i v e r i n e s i t u a t i o n , i t must be remembered t h a t e l i m i n a t i o n of the r i v e r i n e c o n d i t i o n s i s l i k e l y t o e l i m i n a t e or reduce p o p u l a t i o n s of some e x i s t i n g f i s h s p e c i e s , E s t u a r i n e changes and o f f - s h o r e f i s h e r i e s The c o m b i n a t i o n of downstream changes i n the n u t r i e n t and s i l t l o a d i n d u c e d by r e s e r v o i r s , and changes i n e s t u a r i n e s a l i n i t y w i l l b r i n g about b i o l o g i c a l consequences i n the e s t u a r i n e and the o f f - s h o r e a r e a s . These e f f e c t s may i n t u r n b r i n g . a b o u t s e r i o u s economic l o s s e s . The change of e s t u a r i n e s a l i n i t y brought about by reduced r i v e r f l o w and g r e a t e r i n l a n d t i d a l p e n e t r a t i o n may reduce d e s i r a b l e h a b i t a t s f o r some s p e c i e s and e n l a r g e the h a b i t a t s of o t h e r s . As an example, the V o l t a Dam has d e c r e a -sed f l o w on the lower V o l t a R i v e r . There are i n d i c a t i o n s t h a t r i s i n g s a l i n i t y has had an advers e e f f e c t on the c l a m , E q e r i a , which i s of c o n s i d e r a b l e economic i m p o r t a n c e , and which i s not found i n o t h e r l a r g e r i v e r s a l o n g t h a t p a r t of the A f r i c a n c o a s t (Ewer, 1966). The V o l t a problem s h o u l d 69 be l e s s e n e d c o n s i d e r a b l y by t h i s t i m e , as f l o w was i n i t i a l l y v e r y low d u r i n g the r e s e r v o i r f i l l i n g s t a g e . Now, i n an o p e r a t i o n a l s t a g e , the r i v e r f l o w i s back to a h i g h e r l e v e l and i t i s hoped t h a t the clams w i l l r e e s t a b l i s h t h e m s e l v e s . I f t hey do, i t i s a case of good l u c k r a t h e r than p l a n n i n g . Though i n c r e a s i n g s a l i n i t y d e c r e a s e d the h a b i t a t f o r E q e r i a , i t may i n c r e a s e the h a b i t a t s u i t a b l e f o r o t h e r o r g a n i s m s . Thus o y s t e r s which have been p r o t e c t e d from the o y s t e r d r i l l , U r o s a l p i n x c i n e r c a , b y low s a l i n i t i e s which are u n f i t f o r the d r i l l , may now f a l l p rey when r i v e r dam-ming r e d u c e s f l o w and i n c r e a s e s e s t u a r i n e s a l i n i t y . A g a i n , economic i n t e r e s t s may be d e s t r o y e d . The e s t u a r i n e h a b i t a t i s of g r e a t i m p o r t a n c e as an ar e a of h i g h n u t r i e n t l e v e l s which s u p p o r t the p r o d u c t i v i t y of o f f - s h o r e f i s h s p e c i e s . With h i g h n u t r i e n t l e v e l s from the i n f l o w i n g r i v e r , r e l a t i v e t o the sea c o a s t g e n e r a l l y , e s t u a r i e s are c a p a b l e of s u p p o r t i n g l a r g e and p r o d u c t i v e b i o l o g i c a l c o mmunities. Dams, such as the High Aswan, may s e r i o u s l y a l t e r the r a t e of i n p u t of these i m p o r t a n t n u t r i -e n t s . At the d e l t a of the N i l e , " ... the l a c k of ( N i l e ) sediment has reduced p l a n k t o n and o r g a n i c c arbons t o a t h i r d of what they used t o be, e i t h e r k i l l i n g o f f the s a r d i n e s , s c r o m b r o i d s and c r u s t a c e a n s i n the a r e a or d r i v i n g them away" ( S t e r l i n g , 1970, p. 4 6 ) . As a r e s u l t of d e c r e a s e d b i o l o g i c a l p r o d u c t i v i t y i n the N i l e 70 d e l t a a r e a , n u t r i e n t s n e c e s s a r y t o m a i n t a i n the s a r d i n e pop-u l a t i o n are no l o n g e r a v a i l a b l e . The c a t c h which used t o amount t o a p p r o x i m a t e l y 18,000 tons per annum b e f o r e the o p e r a t i o n of the High Aswan dam had dropped t o 500 tons i n 1968 ( D o r c e y , e t a l . , 1972). Though the form of and e f f e c t s of changes i n e s t u a r i n e a r e a s i n d u c e d by r e s e r v o i r s cannot be p r e d i c t e d w i t h a g r e a t d e a l of a c c u r a c y , r e c o g n i t i o n of t h e i r l i k e l i h o o d s h o u l d be g i v e n i n the p l a n n i n g of a l a r g e r e s e r v o i r . T h i s s h o u l d be f o l l o w e d by c a r e f u l m o n i t o r i n g of e s t u a r i n e c o n d i t i o n s a f t e r c l o s i n g of the dam, and i n c l u s i o n of p l a n s f o r d e c r e a s i n g i n i t i a l water s t o r a g e i f n e c e s s a r y t o m a i n t a i n d e s i r a b l e e s t u a r i n e c o n d i t i o n s . THE BIOLOGICAL STABILIZATION OF RESERVOIRS The e s t a b l i s h m e n t of a s t a b l e , i n t e r d e p e n d e n t b i o l o g i c a l community i n a r e s e r v o i r i s not a r a p i d p r o c e s s . I n i t i a l l y the h i g h n u t r i e n t l e v e l of the newly formed l a k e w i l l l e a d t o h i g h p r o d u c t i v i t y and g r e a t p o p u l a t i o n growth of many s p e c i e s . T h i s s i t u a t i o n s h o u l d p e r s i s t f o r s e v e r a l y e a r s , w i t h growth of weeds such as the S a l v i n i a i n Lake K a r i b a and h i g h f i s h c a t c h e s as i n d i c a t o r s . A few y e a r s a f t e r the f i l l -i n g of a r e s e r v o i r , however, b i o l o g i c a l p r o d u c t i o n w i l l d e c r e a s e and some s p e c i e s p o p u l a t i o n s w i l l d e c l i n e . T h i s 71 p r o c e s s i s brought on both by the d e c r e a s e i n n u t r i e n t l e v e l s and by the i n a b i l i t y of some s p e c i e s t o adapt. At Lake K a r i b a , the i n i t i a l l y h i g h p o p u l a t i o n of bream, T i l a p i a  m o r t i m e r i , d e c l i n e d r a p i d l y a f t e r 1968, e i t h e r because of i n a b i l i t y t o adapt c o m p l e t e l y t o the l a c u s t r i n e s i t u a t i o n , or because of p o p u l a t i o n a d j u s t m e n t s r e l a t i v e t o i t s p r e d a t o r , the t i g e r f i s h ( C o u l t e r , 1967). The c r e a t i o n of a nsuj h a b i t a t i s v e r y l i k e l y t o p r e s e n t n i c h e s which w i l l not be f i l l e d n a t u r a l l y f o r many y e a r s . T h i s f a c t o r may encourage i n t r o d u c t i o n of new s p e c i e s , which appear t o be h i g h l y d e s i r a b l e , and which may be w e l l equipped to contend w i t h a d v e r s e c o n d i t i o n s such as draw-down or water t u r b i d i t y . However, " ... the whole q u e s t i o n of i n t r o d u c i n g organisms t o e n v i r o n m e n t s f o r e i g n t o them and where they may have no n a t u r a l enemies or p a r a s i t e s i s d e l i c a t e and f r a u g h t w i t h danger ... " ( J a c k s o n , 1966, p. 6 3 ) . An example of a s p e c i e s which has been i n t r o d u c e d i n t r o p i c a l a r e a s i s the c a r p , C y p r i n u s c a r p i s . T h i s f i s h b reeds w e l l i n most of the s i t u a t i o n s where i t has been i n t r o d u c e d , and heavy f i s h i n g i s r e q u i r e d t o p r e v e n t d e s t r u c t i o n o f o t h e r organisms growing on the l a k e bottoms ( J a c k s o n , 1 9 66), U l t i m a t e s t a b i l i z a t i o n of r e s e r v o i r b i o t a w i l l take many y e a r s . R u s s i a n r e s e a r c h i n t h i s r e g a r d has been q u i t e e x t e n s i v e and f i n d i n g s might be summarized by these examples: / / 72 "Where r e s e r v o i r s have been obser v e d f o r l o n g e r p e r i o d s , p r e v i o u s a s s u m p t i o n s of q u i c k s t a b i l i z a t i o n had t o be r e v i s e d . In the U t c h i n s k r e s e r v o i r on the ffloska-Volga c a n a l z o o p l a n k t o n became more or l e s s s t a b i l i z e d o n l y a f t e r t e n y e a r s and then i s s t i l l s u b j e c t t o a n n u a l f l u c t u a t i o n s . Bottom faunas on the V o l g a r e s e r v o i r s mere s t i l l l a b i l e a f t e r e i g h t e e n t o t w e n t y - t h r e e y e a r s , " ( R z o s k a , 1966, p. 152), Adjustment of the p o p u l a t i o n s of the many s p e c i e s a f f e c t e d by any r e s e r v o i r p r o j e c t w i l l take c o n s i d e r a b l e t i m e , and i t w i l l not be u n t i l the complex r e l a t i o n s h i p s between s p e c i e s are b a l a n c e d t h a t b i o l o g i c a l s t a b i l i t y o c c u r s . * * * T h i s c o n c l u d e s the s e c t i o n d e a l i n g w i t h the b i o l o g i c a l e f f e c t s of r e s e r v o i r s . Though, t o a b i o l o g i s t the depth and l e v e l of the m a t e r i a l c o v e r e d may seem s u p e r f i c i a l , i t w i l l be most u s e f u l as p a r t of the background which i s n e c e s -s a r y i n o r d e r t o approach c o m p i l a t i o n of the impact i d e n t -i f i c a t i o n framework. The nature' of some of the e f f e c t s which have been d i s c u s s e d s h o u l d a l s o s e r v e t o r e i n f o r c e the f a c t t h a t a new and more comprehensive approach i s n e c e s s a r y i n the p l a n n i n g of l a r g e r e s e r v o i r s . Though sec o n d a r y e f f e c t s cannot be p r e d i c t e d w i t h a b s o l u t e c e r t a i n t y , i t i s d e f i n i t e l y p o s s i b l e t o i n d i c a t e p o t e n t i a l e f f e c t s , based on p a s t e x p e r i e n c e , and t o make w e l l based judgements as t o the e f f e c t s of p a r t i c u l a r proposed r e s e r v o i r p r o j e c t s . 73 THE HUMAN AND CULTURAL EFFECTS OF LARGE RESERVOIRS C r e a t i o n of a l a r g e r e s e r v o i r w i l l have a c o n s i d e r a b l e e f f e c t on the l i v e s of many p e o p l e . For some, t h e r e may be ad v a n t a g e s , but al m o s t c e r t a i n l y f o r o t h e r s t h e r e w i l l be s e r i o u s drawbacks. The r e s e r v o i r ' s e x i s t e n c e w i l l open o p p o r t u n i t i e s f o r new. l i f e s t y l e s , f o r new forms of l a n d use and f o r improved a c c e s s i n t o p r e v i o u s l y remote a r e a s . How-e v e r , the i n u n d a t i o n of a l a r g e l a n d a r e a w i l l e r a s e , i n p r a c t i c a l terms f o r e v e r , the o p p o r t u n i t i e s p r e v i o u s l y e x i s t -i n g on t h a t l a n d . I t i s e s s e n t i a l t h a t the human a s p e c t s of r e s e r v o i r c r e a t i o n be c o n s i d e r e d c a r e f u l l y , and t h a t proposed p r o j e c t s do not become s i n g l e o b j e c t i v e s t r u c t u r e s , advantageous o n l y t o a s p e c i f i c user group which may be many m i l e s from the s i t e . E a r l y p l a n n i n g of the o p p o r t u n i t i e s a l a r g e r e s e r v o i r c r e a t e s f o r the l o c a l p o p u l a t i o n i s e s s e n t i a l . S e v e r a l p o i n t s s u p p o r t t h i s s t a t e m e n t . F i r s t , c o n s t r u c t i o n of f a c i l i t i e s f o r human use w i t h i n , or i m m e d i a t e l y a d j a c e n t t o the r e s e r v o i r i s l e s s e x p e n s i v e b e f o r e r e s e r v o i r f i l l i n g than a f t e r . Harbours and c h a n n e l s can be more e a s i l y c o n -s t r u c t e d w h i l e the l a n d i s dry than a f t e r i n u n d a t i o n , So t o o , c l e a r i n g of a r e a s a l o n g the shore f o r f i s h i n g or r e c r e -a t i o n i s a . f a r l e s s complex o p e r a t i o n b e f o r e the e x i s t i n g v e g e t a t i o n i s f l o o d e d , A second f a c t o r which n e c e s s i t a t e s / / 74 e a r l y p l a n n i n g of such o p e r a t i o n s as the r e l o c a t i o n of i n d i g -enous p o p u l a t i o n s i s the p o s s i b i l i t y of e a r l y c o m p l e t i o n of the dam. The I t a l i a n c o n s t r u c t i o n f i r m r e s p o n s i b l e f o r con-s t r u c t i o n of s e v e r a l A f r i c a n dams has proven i t s e l f c a p a b l e of c o m p l e t i o n of the s t r u c t u r e s b e f o r e the d a t e s s e t as g o a l s by the governments i n i t i a t i n g the p r o j e c t s . U n e x p e c t e d l y e a r l y o p p o r t u n i t y t o s t a r t f i l l i n g a r e s e r v o i r may b r i n g a c r i s i s r esponse t o r e l o c a t e p e o p l e s e v e r a l months ahead of the date p l a n n e d , and b e f o r e r e a s o n a b l e s u r v e y s have been completed on s i t e s f o r r e l o c a t i o n . Comprehensive r e s e r v o i r b a s i n p l a n n i n g a t an e a r l y date may m i n i m i z e c o s t s i n c u r r e d and the d i s r u p t i o n s t o i n d i g e n o u s p o p u l a t i o n s , and c r e a t e a b e t t e r atmosphere f o r i n t r o d u c t i o n of new o p p o r t u n i t i e s . I t has been s t a t e d t h a t : " ... t h e r e a r e o b v i o u s o p p o r t u n i t i e s around man-made l a k e s f o r a l l s t a g e s i n the s u c c e s s i o n of man's a c t i v i t i e s , f o r the h u n t e r , the f i s h e r m a n , the p a s t o r a l i s t , the c u l t i v a t o r and the urban and i n d u s -t r i a l worker. Be f o r e the i n u n d a t i o n , the o p p o r t u n i t i e s f o r human a c t i v i t y a r e , as a r u l e , v e r y much more l i m i t e d . Thus the c r e a t i o n o f a l a k e i s g e n e r a l l y f o l l o w e d by a d i v e r s i f i c a t i o n and a f l o w e r i n g of human endeavor." ( W o r t h i n g t o n , 1966, p. 5 ) . I t i s u n f o r t u n a t e t h a t t h e r e i s good e v i d e n c e t h a t the atmosphere s u g g e s t e d by the l a t t e r p a r t of t h i s s t a t e m e n t i s not o f t e n a c h i e v e d , l e t a l o n e a c h i e v e d i n a smooth and harmon-i o u s manner. A f r i c a n r e s e r v o i r developments p r o v i d e examples: " ... I r r e s p e c t i v e of government a t t i t u d e s towards the l o c a l p o p u l a t i o n and t h e i r development, i n the K a r i b a , V o l t a and Aswan High Dam schemes l i t t l e a t t e n t i o n was / 75 p a i d t o the r e s e t t l e m e n t p r o c e s s u n t i l a f t e r dam s i t e p r e p a r a t i o n s were i n i t i a t e d . " ( S c u d d e r , 1966, p. 9 9 ) . " ... E x p e r i e n c e g a i n e d from K a r i b a , Aswan High Dam and V o l t a schemes has shown c o n c l u s i v e l y i n each case t h a t t h e r e i s too l i t t l e time between the i n i t i a t i o n and c o m p l e t i o n of dam c o n s t r u c t i o n t o c a r r y out and implement the min i m a l r e s e a r c h needed f o r e f f e c t i v e r e h a b i l i t a t i o n a t the time of r e s e t t l e m e n t . R a t h e r , r e s e t t l e m e n t becomes a c r a s h program t o get the people p h y s i c a l l y moved b e f o r e the r i v e r i s s e a l e d o f f . At t h a t time the water l e v e l of the new l a k e can be e x p e c t e d t o r i s e r a p i d l y , " ( S c u d d e r , 1966, p. 100). Wit h o u t e a r l y p l a n n i n g of the human a s p e c t s of a dam c o n s t r u c t i o n and r e s e r v o i r o p e r a t i o n p r o j e c t , t h e r e w i l l be a l e s s than harmonious r e l a t i o n s h i p between the l o c a l p o p u l -a t i o n and the newly c r e a t e d e n v i r o n m e n t . In the f o l l o w i n g s e c t i o n s a t t e n t i o n i s t u r n e d t o some of the s p e c i f i c problems which r e s e r v o i r s have c r e a t e d , and t o some of the o p p o r t u n i t -i e s which u n q u e s t i o n a b l y a r e l o s t . A l s o c o n s i d e r e d a re some of the new o p p o r t u n i t i e s which may be e x p e c t e d . RESETTLEMENT OF INDIGENOUS POPULATIONS E a r l y and comprehensive p l a n n i n g of r e l o c a t i o n p r o -c e d u r e s i s a p r e r e q u i s i t e f o r s u c c e s s f u l o p e r a t i o n of a r e s e r v o i r p r o j e c t . Where such p l a n n i n g i s l a c k i n g , a number of problems a re bound to o c c u r . Even i n c a s e s i n which e v e r y a t t e m p t i s made t o m i n i m i z e d i f f i c u l t i e s , t h e r e w i l l be u n a v o i d a b l e c r i s i s s i t u a t i o n s as people prove t h e m s e l v e s t o be i n d i v i d u a l s r a t h e r than numbers. Depending on the 76 p a r t of the w o r l d i n which the development t a k e s p l a c e , the problems e n c o u n t e r e d w i l l be h i g h l y v a r i a b l e . R e s e t t l e m e n t of Tonga and Uie groups i n R h o d e s i a and Zambia i s a v a s t l y d i f f e r e n t s i t u a t i o n to r e l o c a t i o n of f a r m e r s l i v i n g i n the U n i t e d S t a t e s . Crowding of r e l o c a t e d people As a r e s u l t of r e l o c a t i o n , c r o w d i n g i s a p o t e n t i a l danger, e s p e c i a l l y i n c a s e s i n which r e l o c a t e e s have l i v e d o f f the o l d l a n d s c a p e a t a s u b s i s t e n c e l e v e l . Through the y e a r s a l i f e s t y l e of t h i s type w i l l b u i l d up a s u i t a b l e b a l a n c e between p o p u l a t i o n and s e l f - r e n e w i n g r e s o u r c e s . S u f f i c i e n t l a n d w i l l be a v a i l a b l e so t h a t s o i l s are not over used t o the e x t e n t t h a t t h e i r p r o d u c t i v i t y d e c r e a s e s . Game r e s o u r c e s and p a l a t a b l e n a t u r a l v e g e t a t i o n w i l l be i n an a p p r o x imate b a l a n c e w i t h c onsumption. The p o p u l a t i o n w i l l have d e v i s e d s a n i t a r y p r o c e d u r e s adequate t o p r e v e n t e x c e s -s i v e growth of d i s e a s e v e c t o r s i n d i s p o s a l a r e a s . T h i s b a l a n c e can be broken when r e l o c a t i o n o c c u r s , e i t h e r because of i n s u f f i c i e n t e f f o r t on the p a r t of a u t h o r i t i e s , or because of i n a b i l t i y of a u t h o r i t i e s t o comprehend the r e a s o n s f o r customs, and i n a b i l i t y of the r e l o c a t e d groups t o r e a l i z e the need f o r new and d i f f e r e n t l i f e s t y l e s . The K a r i b a p r o j e c t on the Zambezi R i v e r p r o v i d e s one of 77 b e s t examples of the e f f e c t s of c r o w d i n g of r e l o c a t e d p e o p l e . In one case a group of Tonga were moved from the Zambezi banks t o S i a g a t u b e , where the s o i l was too poor f o r a g r i c u l t u r e . No e f f o r t had been made to encourage a change i n f a r m i n g p r o c e d u r e s and as a r e s u l t of the p e o p l e ' s i n a b i l i t y t o s u s t a i n t h e m s e l v e s , a second move was f o r c e d upon them (Reeve, 196.0). In a n o t h e r c a s e , a l t h o u g h a second .move was not r e q u i r e d , the r e s u l t s were e q u a l l y unhappy: " ... In about 1956-57, a s m a l l group of the Tonga t r i b e w i t h a p o p u l a t i o n of about 1,500 under t h e i r c h i e f , Mola, was moved from the Zambezi v a l l e y as the l a k e began t o f i l l onto a dry mopane c l a d h i l l s i d e near the Bumi R i v e r . Here t h e i r system of a g r i c u l t u r e would not work ( t h e y n o r m a l l y had grown a t a l l v a r i e t y of sorghum which f a i l e d t o mature under the d r i e r c o n d i t i o n s , and a l t h o u g h they had been p r o v i d e d by the A g r i c u l t u r e Department, w i t h a s m a l l , e a r l y m a t u r i n g v a r i e t y , they c o u l d not be persuaded t o grow i t ) . W hile they l i v e d "on the banks of the Zambezi they were a b l e t o supplement t h e i r d i e t w i t h f i s h and r o d e n t s but now they had been moved from the f i s h i n g a r e a and the r o d e n t s were l e s s p l e n t i f u l than they had been by the Zambezi, they s u f f e r e d from severe m a l n u t r i t i o n . " ( A p t e d , e t a l . , 1963, p. 3) The h i s t o r y of r e l o c a t e d Tonga and We people p r e s e n t s much the same s t o r y from one group t o the n e x t . I t i s e s t i m a t e d t h a t i n ten t o f i f t e e n y e a r s t h e i r new l a n d w i l l be so eroded and i n f e r t i l e as a r e s u l t of o v e r u s e , t h a t even sub-s i s t e n c e a g r i c u l t u r e w i l l be v i r t u a l l y i m p o s s i b l e ( S c u d d e r , 1969). M a l n u t r i t i o n of the groups of r e l o c a t e d p e o p l e i s a problem i n i t s e l f , but the e f f e c t s may be worsened where / / / 78 people who are used t o f o r a g i n g come a c r o s s p o i s o n o u s p l a n t s s p e c i e s which are s i m i l a r i n appearance t o those which they are used t o u s i n g , and which t h e y t h e r e f o r e e x p e c t t o have p a l a t a b l e p a r t s . In the K a r i b a a r e a p e o p l e who sought sup-p l e m e n t a l food from a f a m i l i a r l o o k i n g t u b e r o u s r o o t s u f f e r e d severe d e p r e s s i o n of b l o o d sugar l e v e l s and w i d e s p r e a d v o m i t i n g s i c k n e s s (UJaddy, 1966). Inadequate s a n i t a r y f a c i l i t i e s and u n f a m i l i a r methods of o b t a i n i n g water and d i s p o s i n g of wastes have c o m p l i c a t e d K a r i b a s e t t l e m e n t . The Tonga, who had t r a d i t i o n a l l y drawn t h e i r water from the r i v e r and i t s t r i b u t a r i e s were s u p p l i e d w i t h b o r e - h o l e w e l l s ( C o l e , 1960). These h o l e s proved use-f u l p i t s f o r r e f u s e d i s p o s a l , and not s u r p r i s i n g l y , t h e i r c o n t a m i n a t i o n brought on s e r i o u s o u t b r e a k s of d i s e a s e . The l a k e as a s o c i a l b a r r i e r O f ten the r e l o c a t i o n of i n d i g e n o u s groups a l o n g a r i v e r bank p r i o r t o f i l l i n g of a r e s e r v o i r w i l l break down s o c i a l t i e s which have grown between peo p l e on o p p o s i t e s i d e s of the r i v e r . Though a c c e s s a c r o s s the r i v e r a t the dam s i t e may be s u p e r i o r t o any form of a c c e s s which e x i s t e d p r i o r t o c o n s t r u c t i o n , s e t t l e m e n t s a l o n g the r e s e r v o i r s h o r e s w i l l be almost i n a c c e s s i b l e t o o t h e r s e t t l e m e n t s on the o p p o s i t e shore„ / / 79 Lake K a r i b a has p l a c e d a b a r r i e r between groups of the Tonga who f o r m e r l y made f r e q u e n t v i s i t s a c r o s s the r i v e r . K i n s h i p and f r i e n d s h i p t i e s have been sudd e n l y broken by the m i l e s of water and sometimes by a d d i t i o n a l m i l e s of bush which s e p a r a t e s the p o p u l a t i o n of the two s i d e s . S i m i l a r l y , Lake V o l t a has e f f e c t i v e l y s p l i t Ghana i n t o two. F i f t y - t w o new v i l l a g e s s u r r o u n d t h i s l a r g e , d e n d r i t i c l a k e , but commun-i c a t i o n s a l o n g the shore and a c r o s s the l a k e i s d i f f i c u l t . Even i f a t r i p a c r o s s the l a k e was p l a n n e d , the n a t i v e c r a f t would prove t o be t o t a l l y u n l a k e w o r t h y i n the event of a storm. The problem of the b a r r i e r p r e s e n t e d by the c r e a t i o n of a l a r g e l a k e seems i n s o l v a b l e a t p r e s e n t . In t e c h n o l o g i c a l l y advanced a r e a s , new roads may make up f o r the l a c k of c r o s s r i v e r c o n t a c t . In l e s s advanced a r e a s , even i f roa d s were p r o v i d e d , they would have l i t t l e u t i l i t y i n p e r m i t t i n g s o c -i a l c o n t a c t , a t l e a s t i n the near f u t u r e . D i s e a s e : p h y s i c a l and p s y c h o l o g i c a l F o l l o w i n g r e l o c a t i o n t h e r e i s o f t e n a marked d e c l i n e i n the h e a l t h of the p o p u l a t i o n . T h i s stems both from c o n t a c t w i t h new forms of d i s e a s e v e c t o r s , and from a g e n e r a l l o w e r i n g of the morale of the people i n v o l v e d . The l a t t e r , p s y c h o l o g -i c a l f a c t o r cannot be o v e r l o o k e d , as t h e r e i s e v i d e n c e t h a t 80 r e s i s t a n c e t o d i s e a s e d e c r e a s e s and the death r a t e i n c r e a s e s a f t e r groups are r e l o c a t e d . The v e r y r e a l s t r e s s accompany-i n g r e s e t t l e m e n t and a d j u stment must be c r e d i t e d f o r d e c r e a s -i n g the p o p u l a t i o n ' s a b i l i t y to contend w i t h day to day problems ( S c u d d e r , 1966). Of g r e a t e r c o n c e r n , however, are the l o n g e r term changes i n d i s e a s e p a t t e r n s which are brought about by r e s e r v o i r c o n s t r u c t i o n . Perhaps of g r e a t e s t c o n c e r n i s the spread of b i l h a r z i a i n t r o p i c a l a r e a s . T h i s p a r a s i t e i n d u c e d d i s e a s e i s t r a n s m i t t e d t o people by c o n t a c t w i t h c e r t a i n s n a i l s p e c i e s which can e x i s t o n l y i n r e l a t i v e s t a b l e w a t e r s : r e s e r v o i r s and slow r u n n i n g i r r i g a t i o n c a n a l s are i d e a l h a b i t a t s . In the worst c a s e s , i n f e c t i o n w i t h b i l h a r z i a can r e s u l t i n p a r a p l e g i a or d e a t h , and s i n c e the c o n s t r u c t i o n of l a r g e A f r i c a n r e s e r v o i r s , death r a t e s from the d i s e a s e have r i s e n s h a r p l y . The d i s e a s e appears t o have a number of o t h e r u n d e s i r a b l e e f f e c t s . D y s e n t r y i s the most o b v i o u s , but t h e r e are i n d i c a t i o n s t h a t h e i g h t and weight are r e t a r d e d and t h a t p h y s i c a l s t a m i n a i s lowered by the d i s e a s e ( J o r d a n and R a n d a l l , 1962). The e f f e c t t h a t s u b s t a n t i a l p o r t i o n s of the p o p u l a t i o n s u f f e r i n g from b i l h a r z i a w i l l have on a n t i c i p a t e d development remains t o be seen. C e r t a i n l y , i t w i l l be an u n d e s i r a b l e e f f e c t and a most s e r i o u s drawback f o r groups who a l r e a d y have many o t h e r problems i n r e a d j u s t m e n t and development. 81 CHANGES IN LAND UTILIZATION AND EMPLOYMENT  F i s h i n g C r e a t i o n of a l a r g e r e s e r v o i r p r e s e n t s an environment w e l l s u i t e d t o the development of f i s h e r i e s ; e i t h e r commer-c i a l , or r e c r e a t i o n a l , or b o t h . I f a c o m m e r c i a l f i s h e r y i s l i k e l y t o d e v e l o p , c o n s i d e r a t i o n must be g i v e n t o i m p o s i t i o n o f c a t c h q uotas to ensure a s u s t a i n e d y i e l d . Without such r e g u l a t i o n the i n i t i a l h i g h l e v e l of b i o l o g i c a l p r o d u c t i v -i t y i s l i k e l y to encourage e x p a n s i o n of f i s h i n g beyond the l e v e l which the r e s e r v o i r i s c a p a b l e of m a i n t a i n i n g . Over-f i s h i n g and d e p l e t i o n of s t o c k s w i l l , of c o u r s e , lower the r e s e r v o i r ' s p r o d u c t i v i t y f o r a number of y e a r s . A c cess i s a f a c t o r i n development of a v i a b l e c o m m e r c i a l or r e c r e a t i o n a l f i s h e r y . C o n s i d e r a t i o n i s r e q u i r e d i n the m a t t e r of i n c e n t i v e s f o r groups p r e p a r e d t o r i s k c a p i t a l i n the e x t a b l i s h m e n t of c o l l e c t i o n and p r o c e s s i n g s e r v i c e s . The m a t t e r of anadromous f i s h i s one which p r e s e n t s a problem t o a u t h o r i t i e s p l a n n i n g a dam c o n s t r u c t i o n p r o j e c t . At K a r i b a i t was d e c i d e d t h a t m i g r a t o r y s p e c i e s d i d not w a r r a n t the e x t r a c o s t of f i s h l a d d e r s ; c o n s e q u e n t l y , l a r g e numbers of e e l s g a t h e r e d near the f a c e of the dam soon a f t e r i t was c l o s e d . Without a b i l i t y to complete t h e i r l i f e c y c l e 82 the c o n t i n u e d e x i s t e n c e of the p o p u l a t i o n i s j e o p a r d i z e d . For the l a s t s e v e r a l decades the a t t i t u d e towards anadromous f i s h , a t p r o j e c t s on European and No r t h American r i v e r s , has been q u i t e d i f f e r e n t t o t h a t a p parent a t K a r i b a . Perhaps the l a s t major dam c o n s t r u c t e d w i t h o u t heed f o r m i g r a t o r y salmon was the Grand Coulee on the Columbia R i v e r . T h i s p r o j e c t , s t a r t e d i n the 1930's, e l i m i n a t e d over 1,000 m i l e s .of major r i v e r s and c r e e k s s u i t a b l e f o r spawning. 8 o n n e v i l l e Dam, c o n s t r u c t e d near the mouth of the Columbia R i v e r d u r i n g the same p e r i o d , had no i n i t i a l p l a n n i n g f o r f i s h l a d d e r s , but a f t e r c o n s t r u c t i o n had s t a r t e d the o u t c r y of c o n s e r v a t -i o n i s t s f o r c e d i n c l u s i o n of f i s h h a n d l i n g f a c i l i t i e s ( B u l l a r d , 1968), Had they not been i n c l u d e d , what today amounts t o a m u l t i - m i l l i o n d o l l a r i n d u s t r y would not e x i s t . The a t t i t u d e of a u t h o r i t i e s towards f i s h i n g w i l l have a major i n f l u e n c e on o c c u p a t i o n s of many of the people a f f e c t e d by r e s e r v o i r p r o j e c t s . The p o t e n t i a l f o r g a i n f u l employment r e p r e s e n t e d by f i s h e r i e s w a r r a n t s c a r e f u l c o n s i d e r a t i o n and p l a n n i n g , whether i n a de v e l o p e d a r e a or a d e v e l o p i n g one, and whether the f i s h are anadromous or spend t h e i r f u l l l i f e c y c l e w i t h i n the r e s e r v o i r . A g r i c u l t u r e C r e a t i o n of a r e s e r v o i r may have both p o s i t i v e and / / • / 83 n e g a t i v e a s p e c t s i n the f i e l d of a g r i c u l t u r e . I t would seem a f a i r a s s u m p t i o n t h a t i f o p e r a t i o n s are p r o p e r l y e x e c u t e d the p o s i t i v e a s p e c t s of i n c r e a s i n g a g r i c u l t u r a l o utput t h r o u g h i r r i g a t i o n s h o u l d a t l e a s t e q u a l the n e g a t i v e a s p e c t s which i n c l u d e i n u n d a t i o n o f e x i s t i n g f a r m l a n d and l o s s of sediment d e p o s i t i o n on downstream a l l u v i a l farms. The problem of o v e r - c r o p p i n g of a g r i c u l t u r a l l a n d may a r i s e as a n e g a t i v e consequence of i n t e n s i f i c a t i o n or expan-s i o n of f a r m i n g i n t o p r e v i o u s l y unfarmed a r e a s . The a b i l i t y of the s o i l t o m a i n t a i n f e r t i l i t y , e s p e c i a l l y i n t r o p i c a l a r e a s , i s not as g r e a t as the average farmer who wishes t o maximize the v a l u e of h i s c r o p s i s l i k e l y t o d e s i r e . Over-c r o p p i n g the l a n d w i l l - l e a d t o s o i l i n f e r t i l i t y ; o v e r -i r r i g a t i o n or o v e r - g r a z i n g w i l l l e a d t o e r o s i o n . Steps must be taken t o ensure t h a t these problems are not p e r m i t t e d to a r i s e a f t e r the a g r i c u l t u r a l o p p o r t u n i t i e s a f f o r d e d by a r e s e r v o i r are taken-up by the l o c a l p o p u l a t i o n . R e c r e a t i o n C r e a t i o n of a l a r g e r e s e r v o i r w i l l have a c o n s i d e r a b l e e f f e c t on r e c r e a t i o n a l o p p o r t u n i t i e s . These w i l l be i n i t i a t e d by c o n s t r u c t i o n or improvement of a c c e s s roads t o the dam s i t e , and w i l l be enhanced as the r e s e r v o i r f i l l s and the l a k e l e v e l s t a b i l i z e s . The i m p o r t a nce of t o u r i s m s h o u l d not 8 4 be u n d e r e s t i m a t e d , f o r i t i s e s t i m a t e d t h a t the demand f o r o utdoor r e c r e a t i o n w i l l t r i p l e i n the t h r e e decades p r e c e d i n g the year 2000 i n a r e a s such as the U n i t e d S t a t e s , as working hours are d e c r e a s e d and a f f l u e n c e i n c r e a s e s . Consequences of r e c r e a t i o n a l a c t i v i t y may a d v e r s e l y a f f e c t the g e n e r a l c o n d i t i o n of the r e s e r v o i r a r e a . Overuse of r o a d s , camping a r e a s , w i l d l i f e and f i s h w i l l not o n l y d e c r e a s e the v a l u e of the r e c r e a t i o n a l e x p e r i e n c e , but a l s o may have a l o n g term e f f e c t on the s u i t a b i l i t y of the l o c a t i o n f o r f u r t h e r a c t i v i t y . PERMANENT LOSS OF NATURAL AND HISTORIC FEATURES As a r e s e r v o i r f i l l s i t may i n u n d a t e and u l t i m a t e l y bury under s i l t , n a t u r a l and h i s t o r i c f e a t u r e s which a r e of g r e a t c u l t u r a l v a l u e . These may i n c l u d e l o c a t i o n s of g r e a t s c e n i c b e a u t y , b u r i a l grounds of s i g n i f i c a n c e t o r e l a t e d o f f s p r i n g , h i s t o r i c a l p o i n t s of i n t e r e s t and p r e h i s t o r i c and unknown l o c a t i o n s where a r t i f a c t s might one day have been found. Though c o n s i d e r a t i o n of these f e a t u r e s and s i t e s would appear t o have been m i n i m a l , t h e r e w i l l be i n c r e a s i n g p r e s s u r e f o r such c o n s i d e r a t i o n i n f u t u r e p r o j e c t s . In the r e s e r v o i r development of the Columbia R i v e r we may l o o k t o s e v e r a l examples of l o s s of i m p o r t a n t s i t e s . 85 C e l i l o L a k e , be h i n d the D a l l e s Dam, i n u n d a t e s C e l i l o F a l l s which was a s i t e of g r e a t n a t u r a l b e a u t y , and which a l s o had s i g n i f i c a n c e w i t h r e s p e c t t o t r e a t y I n d i a n f i s h i n g r i g h t s . At l e a s t one a n t h r o p o l o g i s t a l s o b e l i e v e s t h a t the l a k e c o v e r s remains of one of the o l d e s t s e t t l e m e n t s i n No r t h America. C o n t i n u i n g upstream, i t i s u n d i s p u t e d t h a t the s e r i e s of l a r g e r e s e r v o i r s c o v e r many p e t r o g r a p h s which might have p r o v i d e d a v a l u a b l e h i s t o r i c r e c o r d of the c u l t u r e and r e l i g i o n o f e a r l y i n h a b i t a n t s . Near the c o n f l u e n c e w i t h the Snake R i v e r , the Lower monumental Dam i n u n d a t e s a l o c a -t i o n where bones da t e d between e l e v e n and t h i r t e e n thousand y e a r s o l d were uncovered i n a l a s t moment e x c a v a t i o n e f f o r t by the U n i t e d S t a t e s Army Corps of E n g i n e e r s ( B u l l a r d , 1 9 6 8 ). Many o t h e r s i t e s of a e s t h e t i c v a l u e have a l s o been e l i m i n a t e d a l o n g the co u r s e of the Columbia R i v e r , There i s l i t t l e a l t e r n a t i v e t o the i n u n d a t i o n of s i t e s c o n s i d e r e d t o be of v a l u e , so l o n g as r e s e r v o i r c o n s t r u c t i o n p r o j e c t s a re c o n s i d e r e d t o be a n e c e s s a r y element i n the development p r o c e s s . C a r e f u l i n v e n t o r i e s of the l a n d t o be i n u n d a t e d may en a b l e measures t o be ta k e n t o p r e s e r v e a t l e a s t those elements of the l a n d s c a p e which are removable. E x t e n s i v e f i l m r e c o r d s may a l s o p l a y t h e i r p a r t i n compensat-i n g f o r the u l t i m a t e l o s s , * * * / / / 8 6 The human and c u l t u r a l e f f e c t s of the b u i l d i n g of dams and c r e a t i o n of l a r g e r e s e r v o i r s are g e n e r a l l y consequences of i m p a c t s w i t h i n the p h y s i c a l and b i o l o g i c a l c l a s s e s . As t h e r e i s a degree of u n c e r t a i n t y about the o c c u r r e n c e and e x t e n t of these i m p a c t s , i t f o l l o w s t h a t t h e r e w i l l be a degree of u n c e r t a i n t y about human and c u l t u r a l e f f e c t s . There i s c e r t a i n t y , however, t h a t r e s e r v o i r p r o j e c t s w i l l provoke secondary e f f e c t s . F u r t h e r , t h e r e i s e v i d e n c e t h a t these e f f e c t s have been u n a n t i c i p a t e d i n p a s t p r o j e c t s , and t h a t a l a c k of c o n s i d e r a t i o n and p l a n n i n g has worsened e f f e c t s which might have been s a t i s f a c t o r i l y r educed or p r e v e n t e d . THE EFFECT OF UNPREDICTABLE NATURAL EVENTS The f i n a l type of e f f e c t s t o be d i s c u s s e d a re those which r e s u l t as a consequence of the pr e s e n c e of the dam and r e s e r v o i r , c o u p l e d w i t h some n a t u r a l l y o c c u r r i n g , but t o t a l l y u n p r e d i c t a b l e , n a t u r a l e v e n t . In t h e m s e l v e s , the n a t u r a l e v e n t s may have s e r i o u s consequences f o r man, but because of the presence of the dam and r e s e r v o i r , the con-sequences are c o n s i d e r a b l y compounded. P r o b a b l y the most d i s a s t r o u s n a t u r a l event which c o u l d a f f e c t the o p e r a t i o n o f a dam and r e s e r v o i r i s a h i g h m a g n i t -ued e a r t h q u a k e . T h i s s e i s m i c a c t i v i t y c o u l d , a t w o r s t , cause 87 c o l l a p s e of a dam and i n t e n s e downstream f l o o d i n g , perhaps combined w i t h the washout of o t h e r dams. A lower o r d e r e f f e c t might i n v o l v e the c r e a t i o n of a wave w i t h i n the r e s e r v o i r , e i t h e r d i r e c t l y , or by d i s p l a c e m e n t of water by a l a n d s l i d e . In t h i s case t h e r e would be p o t e n t i a l f o r s e r i o u s damage t o shore f a c i l i t i e s and f o r s p i l l i n g of l a r g e volumes of water over the dam. The proponent of a r e s e r v o i r scheme can i n d i c a t e the i m p r o b a b i l i b y of an ea r t h q u a k e d i s a s t e r . Based on both the background of s e i s m i c a c t i v i t y i n an a r e a , and the e n g i n e e r e d f e a t u r e s of the dam to r e s i s t v i b r a t i o n of i t s f o u n d a t i o n s , i t i s p o s s i b l e t o e s t a b l i s h a h i g h degree of i m p r o b a b i l i t y f o r damage from e a r t h q u a k e s . I t i s r e c o g n i z e d , f o r example, t h a t c l a y c o r e , r o c k w a l l e d dams have a h i g h r e s i s t a n c e t o damage from s e i s m i c a c t i v i t y . N e v e r t h e l e s s , t h e r e i s always the p o s s i b i l i t y of an ea r t h q u a k e l e a d i n g t o the d e s t r u c t i o n o f a dam. Where a dam, such as K a r i b a , has been b u i l t u s i n g the c o n c r e t e a r c h p r i n c i p l e , w i t h a major f a u l t p a r a l l e l t o and nearby the Zambezi R i v e r , the p o t e n t i a l must be i n c r e a s e d c o n s i d e r a b l y ( C h u r c h , 1968), Another n a t u r a l event which may l e a d t o unexpected i m p a c t s i s a change i n h y d r o l o g i c a l p a t t e r n s . Unexpected l o n g - t e r m changes i n r a i n f a l l have the p o t e n t i a l f o r r e n d e r -i n g a dam v i r t u a l l y u s e l e s s , or f o r o v e r f i l l i n g a r e s e r v o i r . 88 The Owen F a l l s Scheme, b u i l t d u r i n g 1949 to 1954, p r o v i d e s an i n t e r e s t i n g example (Lane, 1970). Here, a rock w e i r has been used a t the o u t f l o w of Lake V i c t o r i a i n t o the White N i l e t o r a i s e the l a k e l e v e l . Based on 50 y e a r s ' d a t a , the o u t f l o w c a p a c i t y of the scheme was ample, however i n 1961 i n f l o w i n c r e a s e d by 50 p e r c e n t over the p r e v i o u s maximum i n what by then amounted to 66 y e a r s of r e c o r d s . The o u t f l o w was exceeded by i n f l o w , and l a k e waters r o s e , i n u n d a t i n g p o r t f a c i l i t i e s , f a c t o r i e s , r o a d s , houses', and a g r i c u l t u r a l l a n d . P r e v e n t i o n of e v e n t s such as eq r t h q u a k e s and changes i n the h y d r o l o g i c c y c l e i s o b v i o u s l y i m p o s s i b l e . A l l o w a n c e must t h e r e f o r e be made i n i n i t i a l p l a n n i n g i n case unexpected n a t u r a l e v e n t s l e a d t o i m p a c t s of d i s a s t r o u s s c a l e . * * # W i t h i n the pages of t h i s s e c t i o n the e f f e c t s of dam b u i l d i n g and r e s e r v o i r c r e a t i o n have been documented and d i s c u s s e d . Examples were s e l e c t e d from a l a r g e number of r e s e r v o i r p r o j e c t s a t v a r i o u s s i t e s i n both t r o p i c a l and temperate e n v i r o n m e n t s . Coverage was g i v e n t o c o n c r e t e a r c h and e a r t h f i l l t y p e s of dams; t o impoundment of waters i n r e l a t i v e l y s h a l l o w r e s e r v o i r s i n a r e a s of minor r e l i e f , and t o impoundment w i t h i n narrow, s t e e p s i d e d r i v e r v a l l e y s . Though t h e r e can be no guarantee t h a t e v e r y s econdary e f f e c t 89 of e v e r y r e s e r v o i r p r o j e c t which has been or w i l l be b u i l t i s c o v e r e d , the examples r e p r e s e n t major e f f e c t s which have been e x p e r i e n c e d a t the l o c a t i o n s i n d i c a t e d i n the t e x t . A l s o , t hey p r o v i d e the background f o r b u i l d i n g of the impact i d e n t i f i c a t i o n framework which i s d i s c u s s e d i n the next c h a p t e r . 90 3. DEVELOPMENT OF AN IMPACT IDENTIFICATION FRAMEWORK RECOGNITION OF THE NEED FOR IMPACT IDENTIFICATION The need f o r a comprehensive approach i n i d e n t i f i c a t i o n of the i m p a c t s of l a r g e s c a l e c o n s t r u c t i o n p r o j e c t s has • r e c e i v e d i n c r e a s i n g r e c o g n i t i o n i n r e c e n t y e a r s . In the U n i t e d S t a t e s , the " N a t i o n a l E n v i r o n m e n t a l P o l i c y Act of 1969" r e q u i r e s t h a t a l l f e d e r a l a g e n c i e s " ... i d e n t i f y and de v e l o p methods and p r o c e d u r e s ... which w i l l i n s u r e t h a t p r e s e n t l y u n q u a n t i f i e d e n v i r o n -mental a m e n i t i e s and v a l u e s may be g i v e n a p p r o p r i a t e c o n s i d e r a t i o n i n d e c i s i o n making a l o n g w i t h economic and t e c h n i c a l c o n s i d e r a t i o n s " ( S e c t i o n 1 0 2 ( 2 ) 8 ) . To meet t h i s r e q u i r e m e n t , u n d e r t a k i n g s by f e d e r a l a g e n c i e s a f f e c t i n g the q u a l i t y of the human environment must be p r e -ceded by a d e t a i l e d statement of e n v i r o n m e n t a l i m p a c t , i n c -l u d i n g i n d i c a t i o n of not o n l y the i r r e v e r s i b l e and i r r e t r i e v -a b l e commitments of r e s o u r c e s , but a l s o the r e l a t i o n s h i p between s h o r t - t e r m uses of the e n v i r o n m e n t , and enhancement of i t s l o n g - t e r m p r o d u c t i v i t y . The Food and A g r i c u l t u r a l O r g a n i z a t i o n of the U n i t e d N a t i o n s r e c o g n i z e d the p r o b a b i l i t y of c r e a t i o n of problems w i t h the development of r e s e r v o i r s i n t h e i r 1969 p u b l i c a t i o n e n t i t l e d "Man-made L a k e s " . "Man-made l a k e s or r e s e r v o i r s are u s u a l l y b u i l t f o r some ' p r i m a r y ' p u r p o s e , but the c o n s t r u c t i o n or pr e s e n c e / 91 of r e s e r v o i r s can c r e a t e 'secondary' problems which may i n v o l v e economic l o s s and human s u f f e r i n g , u n l e s s r e s e r -v o i r p l a n n i n g i n i t s e a r l i e s t s t a g e s t h o r o u g h l y c o n s i d e r s both p r i m a r y and secondary a s p e c t s . " ( L a g l e r , 1969, p. v i i ). Under the a u s p i c e s of the Food and A g r i c u l t u r a l O r g a n i z a t i o n and w i t h the c o o p e r a t i o n of o t h e r U n i t e d N a t i o n s a g e n c i e s , i n t e r n a t i o n a l a s s i s t a n c e i s now a v a i l a b l e t o c o u n t r i e s u n d e r t a k i n g r e s e r v o i r p l a n n i n g , c o n s t r u c t i o n , or r e s e a r c h , TECHNIQUES FOR IMPACT IDENTIFICATION AND AN IDEA The g e n e r a l i n c r e a s e i n c o n c e r n over i m p a c t s of l a r g e c o n s t r u c t i o n p r o j e c t s on the environment has l e d t o c r e a t i o n of new t e c h n i q u e s t o a i d i n t h e i r i d e n t i f i c a t i o n f o r purposes of e v a l u a t i o n or m i n i m i z a t i o n of t h e i r n e g a t i v e e f f e c t s . Two such t e c h n i q u e s i n s p i r e d c o n s i d e r a t i o n of the development of a t e c h n i q u e f o r r e s e r v o i r impact i d e n t i f i c a t i o n . The f i r s t t e c h n i q u e i s a m a t r i x approach t o impact i d e n t i f i c a t i o n and e v a l u a t i o n d e v e l o p e d by Luna B. L e o p o l d and o t h e r s ( 1 9 7 1 ) , and d e s c r i b e d i n a U n i t e d 5 t a t e s G e o l o g i c a l Survey p u b l i c a -t i o n e n t i t l e d "A Proc e d u r e f o r E v a l u a t i n g E n v i r o n m e n t a l Impact". The second, dev e l o p e d by Jens C. Sorensen ( 1 9 7 1 ) , a U n i v e r s i t y of C a l i f o r n i a , B e r k l e y graduate s t u d e n t i n Landscape A r c h i t e c t u r e , uses stepped m a t r i c e s f o r i d e n t i f i c a -t i o n of p o i n t s of r e s o u r c e use c o n f l i c t and d e g r a d a t i o n i n the m u l t i p l e use of c o a s t a l zones. C o n s i d e r a t i o n of the f o r -mer t e c h n i q u e l e d t o the b e l i e f t h a t i t s e a r l y a p p l i c a t i o n / / / / 92 i n assessment of l a r g e c o n s t r u c t i o n p r o j e c t s such as r e s e r -v o i r s would f a i l t o a d e q u a t e l y i d e n t i f y the m u l t i p l e o r d e r consequences of s p e c i f i c i m p a c t s . On the o t h e r hand, the l a t t e r t e c h n i q u e appeared t o show a methodology f o r compre-h e n s i v e i l l u s t r a t i o n of m u l t i p l e o r d e r consequences i n a s p e c i f i c s u b j e c t a r e a . From i t , the i d e a was d e v e l o p e d t h a t i d e n t i f i c a t i o n and i l l u s t r a t i o n of the complex of m u l t i p l e o r d e r consequences of l a r g e r e s e r v o i r c o n s t r u c t i o n p r o j e c t s would be a u s e f u l p r o c e d u r e i n the p l a n n i n g of such p r o j e c t s , i f s e c ondary e f f e c t s were to be a n t i c i p a t e d and t h e i r consequences m i n i m i z e d . A s t e p by s t e p , cause to e f f e c t , or impact t o consequence r e p r e s e n t a t i o n would a i d i n c o m p r e h e n s i v e n e s s . The Leopold e n v i r o n m e n t a l impact e v a l u a t i o n t e c h n i q u e i s s u g g e s t e d as a p r e r e q u i s i t e t o i n i t i a t i o n of a l a r g e p r o j e c t ( F i g u r e 1 ) . I t s c o m p i l a t i o n i s preceded by a r e p o r t on the e x i s t i n g e n v i r o n m e n t a l c h a r a c t e r , or what might be termed an e n v i r o n m e n t a l i n v e n t o r y . T h i s i n v e n t o r y forms the b a s i s f o r s e l e c t i o n of elements of the environment which may be m o d i f i e d , e l i m i n a t e d or removed by the proposed a c t i o n , A comprehensive l i s t of e n v i r o n m e n t a l elements which are l i k e l y t o be s u b j e c t t o impact i s p r o v i d e d as one a x i s of the m a t r i x which i s i n c l u d e d w i t h the p u b l i c a t i o n . The o t h e r a x i s of t h i s m a t r i x l i s t s the p o s s i b l e a c t i o n s of c o n s t r u c t i o n p r o j e c t s , and from i t the a c t i o n s i n v o l v e d i n / / A. Statement of o b j e c t i v e B. T e c h n o l o g i c a l p o s s i b i l i t i e s f o r a c h i e v i n g o b j e c t i v e C. Proposed a l t e r n a t i v e s D. Report on the e x i s t i n g e n v i r o n m e n t a l c h a r a c t e r E. A l t e r n a t i v e e n g i n e e r i n g p l a n s F. IMPACT IDENTIFICATION and e v a l u a t i o n G. Assessment of impact H. Recommendations F i g u r e 1. P o s i t i o n of impact i d e n t i f i c a t i o n i n the assessment of a l t e r n a t i v e p l a n s . (adapted from L.B. L e o p o l d , e t . a l . ) 94 a s p e c i f i c p r o j e c t are s e l e c t e d . A p r o b a b l e impact between an a c t i o n and an element of the environment i s i n d i c a t e d by a s l a s h l i n e a c r o s s the r e s p e c t i v e m a t r i x l o c a t i o n . As an example, a reduced m a t r i x f o r a phosphate m i n i n g l e a s e i s shown ( F i g u r e 2), A f t e r the i d e n t i f i c a t i o n of i m p a c t s , an- e v a l u a t i o n p r o c e d u r e i s e x e c u t e d . For each impact two a p p r a i s a l s are made; f i r s t , the "magnitude" of the i m p a c t , or what might be d e s c r i b e d as the e f f e c t i v e n e s s of the a c t i o n i n a l t e r i n g or c o n t r i b u t i n g t o the d e s t r u c t i o n of the e n v i r o n m e n t a l element, i s e v a l u a t e d on a one t o ten s c a l e . T h i s i s f o l l o w e d by assessment of the " i m p o r t a n c e " of the i m p a c t , a g a i n on a one to ten s c a l e . C o n s i d e r a t i o n of F i g u r e 2 w i l l i n d i c a t e how moderate i m p a c t s on r a r e or unique s p e c i e s a r e c o n s i d e r e d h i g h l y i m p o r t a n t , w h i l e minor i m p a c t s of e r o s i o n a re c o n s i d -e red t o be of low i m p o r t a n c e . F o l l o w i n g n u m e r i c a l e v a l u a t i o n of i m p a c t s , a s u b j e c t i v e assessment of the i m p a c t s of h i g h magnitude or importance i s s u g g e s t e d . The n o v e l method of impact e v a l u a t i o n p r e s e n t e d i n the L e o p o l d p u b l i c a t i o n w a r r a n t s c o n s i d e r a t i o n f o r a p p l i c a t i o n to p l a n n i n g of l a r g e p r o j e c t s such as r e s e r v o i r s . However, i t might be argued t h a t the p o i n t a t which such an assessment i s made i s not the c o r r e c t p o i n t f o r commencing e v a l u a t i o n . R a t h e r , a method i s n e c e s s a r y t o improve the u n d e r s t a n d i n g m 3 < i-t O 3 CD c i -ts H * 3 X I Q> O ci-3 01 CD Q. cr D> >-» ~D cr X CD Q. -o o i ) •-J • 0) •a r - -j - a CO cn • X> 3 " I - CD CD d -• CD X ) O 3 t—' Q . 3 <• 3 CD l O n-• V- 1 CD 0) CD cn • CD • E n v i r o n m e n t a l elements Water q u a l i t y A t m o s p h e r i c q u a l i t y E r o s i o n D e p o s i t i o n . s e d i m e n t a t i o n Shrubs Grasses A q u a t i c p l a n t s F i s h Camping and h i k i n g S c e n i c views and v i s t a s W i l d e r n e s s q u a l i t i e s Rare and unique s p e c i e s H e a l t h and s a f e t y CD m —1 3 CD CD —1 X X ) 3 »-J H « C 1—' >-l H> 3 " D C 3 0) CD U3 CL t-1 1—' n CD -i) CO 3 3 " C CD 77 •1 CD d - CO £ UI 03 o H « 0) O H- 3 cr CO 3 t—1 CD 3 H « CD 3 CO l O CO CO h*-3 CD CD CO 0) Q _ 3 X CD H - CD I-" rt- O o 3 O 3 >—' n CD D . 3 Q. cn CD O CD c : H-CD ->) CO ca Q . cr rt-7T 0) (i- >-J >-j CD CO cr H - H- h - 3 H- CO CD 3 O H-> CD C L u 3 3 h-• CO U3 CD K-• H " CD 3 H- 3 CO Q . 3 l O I D CT CO uildings X ) o t) o cn CD Q. 0> o cr O 3 CO 0) l O 3 H * r f C Q. CD 3 X ) O •1 c i-0) 3 O CD m -< S6 96 of i m p a c t s , t h e i r i n t e r a c t i o n s and t h e i r m u l t i p l e o r d e r consequences, thus e n s u r i n g a f u l l y comprehensive e v a l u a t i o n . To t h i s end, the Sorensen s t u d y appears t o p r o v i d e a u s e f u l framework, upon which m o d i f i c a t i o n s can l e a d t o a d e r i v a t i o n of a comprehensive impact i d e n t i f i c a t i o n methodology. The Sorensen s t u d y u n d e r t a k e s i d e n t i f i c a t i o n of use c o n f l i c t and r e s o u r c e d e g r a d i a t i o n of a c o a s t a l zone. A stepped m a t r i x approach i s used, i n which the p r o s p e c t i v e c o a s t a l zone uses are i n i t i a l l y i d e n t i f i e d a l o n g a v e r t i c a l a x i s . Each of t h e s e uses has a r e q u i r e m e n t f o r c e r t a i n f a c i l i t i e s which are i d e n t i f i e d as " c a u s a l f a c t o r s " on the second, h o r i z o n t a l m a t r i x a x i s . T h i s i n t u r n l e a d s t o a t h i r d , s tepped m a t r i x a x i s upon which " p o s s i b l e a d v e r s e i m p a c t s " i n c l u d i n g i n i t i a l and consequent c o n d i t i o n s a r e i d e n t i f i e d . For example, r e s i d e n t i a l and crop f a r m i n g uses might be c o n s i d e r e d ( F i g u r e 3). I r r i g a t i o n , a n e c e s s i t y f o r c r o p f a r m i n g , may be a " c a u s a l f a c t o r " l e a d i n g t o i n c r e a s e d s u r f a c e r u n o f f , an " i n i t i a l c o n d i t i o n " l e a d i n g t o i n c r e a s e d c l i f f e r o s i o n as a "consequent c o n d i t i o n " , and f i n a l l y t o u n d e r m i n i n g of r e s i d e n t i a l s t r u c t u r e s as a "second o r d e r c o n d i t i o n " . Through comprehensive development of t h i s a pproach a s e r i e s of m a t r i c e s i s d e v e l o p e d which i n d i c a t e the impact of one use upon a n o t h e r , and the e n v i r o n m e n t a l d e g r a d a t i o n r e s u l t i n g as a consequence of a p a r t i c u l a r use. / (3) USES OF LAND Crop farming R e s i d e n t i a l development Xxxxx xxxxxxxx 0—O Note: arrows i n d i c a t e linkage from "use of l a n d " to "causal f a c t o r s " to " i n i t i a l impact" to "consequent impact" to " e f f e c t " . INITIAL IMPACTS Surface r u n o f f Xxxx xxxxxxxx Xxxxxxxxxx CONSEQUENT C l i f f e r o s i o n Xxxx xxxxxx Xxxxx xxxxx EFFECT Undermining Xxxxxx xxxxx Xxxxxxxxxxx Figure 3 . Layout of stepped matrix framework (adapted from Sorensen, 1971) 98 T u r n i n g t o c o n s i d e r a t i o n of r e s e r v o i r s , i t i s r e a d i l y a p p a r e n t when r e v i e w i n g the l i t e r a t u r e , as has been documen-ted i n the p r e v i o u s c h a p t e r , t h a t a l t h o u g h c r e a t i o n of r e s e r v o i r s can l e a d t o f u l f i l l m e n t of a number o f o b j e c t i v e s , the s econdary e f f e c t s r e s u l t i n g from t h e i r o p e r a t i o n a r e u n e x p e c t e d , and are o f t e n s i g n i f i c a n t l y h a r m f u l . The p l a n n i n g approach t o c o n s t r u c t i o n of the s e r e s e r v o i r s has o b v i o u s l y f a i l e d , e i t h e r because of i t s i n a b i l i t y t o p r o v i d e comprehen-s i v e i m p a ct i d e n t i f i c a t i o n , or because of a d e s i r e t o p r e -vent r e c o g n i t i o n and e v a l u a t i o n of a l l i m p a c t s and t h e i r consequences. I f the former i s the c a s e , any methodology t o improve impact i d e n t i f i c a t i o n has p o t e n t i a l f o r s e r v i n g a u s e f u l f u n c t i o n ; i f the l a t t e r , p u b l i c awareness of the p o t e n t i a l i m p a c t s has been p u r p o s e l y r e d u c e d , and d e c i s i o n s made on b e h a l f of the p u b l i c cannot be seen as r e p r e s e n t i n g the o p i n i o n s t h a t they would have, had they more complete i n f o r m a t i o n . A d a p t i o n of the So r e n s e n , stepped m a t r i x approach t o p l a n n i n g of l a r g e r e s e r v o i r s may ser v e t o ensure a comprehen-s i v e approach to e v a l u a t i o n of secondary e f f e c t s , Whether these e f f e c t s are e v a l u a t e d i n c o n v e n t i o n a l b e n e f i t - c o s t terms, or w i t h an approach such as L e o p o l d ' s , or b o t h , i t i s e s s e n t i a l t h a t a l l e f f e c t s which can p o s s i b l y be p r e d i c -ted are f u l l y e v a l u a t e d , and t h a t a t t e n t i o n i s p a i d t o o t h e r p o t e n t i a l e f f e c t s , the consequences of which are 99 u n c e r t a i n . F a i l u r e to do t h i s i n v a l i d a t e s the d e c i s i o n t o c o n s t r u c t one of two or more a l t e r n a t i v e p r o j e c t s t o meet an o b j e c t i v e such as s u p p l y of e l e c t r i c i t y or r e d u c t i o n of f l o o d h a z a r d , THE IMPACT IDENTIFICATION FRAMEWORK The "Impact I d e n t i f i c a t i o n Framework f o r Large R e s e r -v o i r s " ( F i g u r e 4 , p o c k e t ) was d e v e l o p e d through the combin-a t i o n of a s p e c t s of the L e o p o l d and Sorensen approaches w i t h the d a t a which had been accumulated t o c o m p i l e the p r e c e d i n g c h a p t e r . The comprehensive approach of L e o p o l d ' s t e c h n i q u e p r o v i d e d a b a s i s f o r an even more comprehensive f o c u s on a s p e c i f i c f i e l d such as r e s e r v o i r development, w h i l e the format p r e s e n t e d i n the Sorensen s t u d y was i d e a l f o r a d a p t a -i o n t o " o b j e c t i v e - - o p e r a t i o n a l method--impact--consequence" p r e s e n t a t i o n of the r e l e v a n t m a t e r i a l . In the case of r e s e r v o i r s , c e r t a i n p r i m a r y o b j e c t i v e s are f a i r l y o b v i o u s : f l o o d h a z a r d r e d u c t i o n , h y d r o e l e c t r i c g e n e r a t i o n , s u p p l y of i r r i g a t i o n w a t e r , f a c i l i t a t i o n of n a v i g a t i o n and f a c i l i t a t i o n of r e c r e a t i o n . O c c a s i o n a l l y o t h e r o b j e c t i v e s may have been i n c l u d e d i n r e s e r v o i r p l a n s , however, i t would be d i f f i c u l t t o make the case t h a t these o t h e r o b j e c t i v e s are of p r i m a r y c o n c e r n i n the development of most l a r g e r e s e r v o i r s . The o b j e c t i v e s which have been - ' / 1 00 i d e n t i f i e d above are synonymous w i t h the "uses" i d e n t i f i e d f o r the a p p l i c a t i o n of Sorensen's t e c h n i q u e , "Methods of e x e c u t i o n " are the o p e r a t i o n a l p r o c e d u r e s by which the o b j e c t i v e s are o b t a i n e d i n a r e s e r v o i r p r o j e c t . Thus, con-s t r u c t i o n of a dam, d i s r u p t i o n o f l o c a l p o p u l a t i o n , i n i t i a l r e s e r v o i r f i l l i n g , draw-down, e t c e t e r a , are the means or methods of e x e c u t i o n by which the o b j e c t i v e s are a c h i e v e d . Some methods of e x e c u t i o n are e s s e n t i a l f o r achievement of the o b j e c t i v e s , and are i n d i c a t e d as such on the framework. Other methods of e x e c u t i o n w i l l be e s s e n t i a l f o r o n l y c e r t a i n o b j e c t i v e s . Draw-down, f o r example, i s e s s e n t i a l f o r a r e s e r v o i r which i s t o p r o v i d e a r e d u c t i o n of f l o o d h a z a r d , even though i t may have an u n d e s i r a b l e e f f e c t on r e c r e a t i o n and n a v i g a t i o n . I t s h o u l d be noted t h a t i n c a s e s where a p a r t i c u l a r e x e c u t i o n method i s e s s e n t i a l f o r one, but not a l l of the o b j e c t i v e s of a m u l t i - p u r p o s e r e s e r v o i r p r o j e c t , the whole range of p o t e n t i a l e f f e c t s of t h a t method of e x e c u t i o n must be c o n s i d e r e d . To remove the p o t e n t i a l of t hese e f f e c t s i t i s n e c e s s a r y to d i s c a r d the o b j e c t i v e which r e q u i r e s the p a r t i c u l a r method of e x e c u t i o n . Thus, i t may be seep from the framework t h a t the b r o ader the o b j e c t i v e s of a r e s e r v o i r c o n s t r u c t i o n p r o j e c t , the wider the range of p o t e n t i a l s e c o n d a r y e f f e c t s . S t e p p i n g of the m a t r i x l e a d s to i d e n t i f i c a t i o n of i m p a c t s a t the p r i m a r y l e v e l , and then t o a network of the 1 01 m u l t i p l e o r d e r consequences of these p r i m a r y i m p a c t s . I t does not f o l l o w t h a t e v e r y impact and consequence i n d i c a t e d i n the framework w i l l o c cur because of a p a r t i c u l a r r e s e r v o i r p r o j e c t . In f a c t , i t i s i m p o s s i b l e t h a t the whole framework c o u l d a p p l y t o any one p r o j e c t , as i t has been developed f o r r e s e r v o i r s i n d i f f e r e n t c l i m a t i c a r e a s , and some e f f e c t s are e x c l u s i v e t o c e r t a i n l i m i t e d a r e a s . The framework becomes a check l i s t f o r the i d e n t i f i c a t i o n of i m p a c t s and consequences which must precede e v a l u a t i o n p r o c e d u r e s . E v a l u a t i o n i s not i n t e n d e d t o be a c e n t r a l i s s u e i n t h i s s t u d y . I t may be monetary, as i n b e n e f i t - c o s t , i t may f o l l o w a scheme such as L e o p o l d ' s , or i t may be s u b j e c t i v e (a s i m p l e example of an e v a l u a t i o n method has been p r o v i d e d i n the i n s t r u c t i o n s on the framework). The p r i m a r y o b j e c t i v e of the framework, however, i s t o ensure t h a t a comprehensive i d e n t i f i c a t i o n of s econdary e f f e c t s p e r m i t s a complete e v a l u a t i o n , r e g a r d -l e s s of the pr o c e d u r e used. I t w i l l be noted t h a t some e f f e c t s are i n d i c a t e d a number of ti m e s on the framework, e i t h e r stemming d i r e c t l y from methods of e x e c u t i o n , or from m u l t i p l e o r d e r consequences. Rather than go through the complete s e t of consequences i n each of these c a s e s , r e f e r e n c e i s made to a p o i n t on the framework a t which the complete p r e s e n t a t i o n may be found. T h i s s e r v e s t o s i m p l i f y the framework and reduces i t s s i z e . I t would, of c o u r s e , be p o s s i b l e t o s e p a r a t e t h e s e r e c u r r i n g 1 02 i m p a c t s from the framework f o r i l l u s t r a t i o n as impact subframeworks. L i t t l e advantage i s seen i n t h i s form of s e p a r a t i o n , a t l e a s t f o r the purpose of p r e s e n t i n g the met-ho d o l o g y , so such s e p a r a t i o n has not been a t t e m p t e d . For a c t u a l a p p l i c a t i o n of the framework, however, a f i n a l p r e s e n -t a t i o n format might be adopted i n which l i n k a g e s of p r o b a b l e i m p a c t s are i n d i c a t e d . t o t h e i r u l t i m a t e p r o b a b l e or p o t e n t -i a l consequence, w h i l e o t h e r , i m p r o b a b l e l i n k a g e s are t e r m i n -a t e d a t the p o i n t a t which the f i r s t i m p r o b a b l e consequence i s i n d i c a t e d . The term " f i n a l consequence" i s open t o c r i t i c i s m , bec-ause i n e f f e c t the f i n a l consequence w i l l never be i n d i c a t e d . I f downstream e r o s i o n causes u n d e r c u t t i n g of bank f a c i l i t i e s , the damage t o bank f a c i l i t i e s might be c o n s i d e r e d as a f i n a l consequence. Another approach would be to g i v e an i n d i c a t i o n of the r e m e d i a l measures r e q u i r e d to p r e v e n t d e s t r u c t i o n of the bank f a c i l i t i e s . But, t h i s r e m e d i a l measure may be con-s i d e r e d t o have consequences e l s e m h e r e , and so on ad i n f i n i t u m . The whole d i s c u s s i o n , though not the c r i t i c i s m , b r e a k s down. Thus, f o r p r e s e n t a t i o n p u r p o s e s , t e r m i n a t i o n i s g e n e r a l l y a t the consequence which p r e c e d e s the d i r e c t e f f e c t on man, a t the d i r e c t e f f e c t on man, i t s e l f , or a t the r e m e d i a l measure which i s n e c e s s a r y to a l l e v i a t e the e f f e c t . 1 03 The framework which had been dev e l o p e d appears to have p o t e n t i a l f o r i n d i c a t i n g the broad range of consequences or secondary e f f e c t s t o which development of r e s e r v o i r s may l e a d . Though i t i s r e a l i z e d t h a t o m i s s i o n s i n the framework w i l l p r o b a b l y be foun d , as i t s t a n d s a t p r e s e n t , the p r i n c i p a l e f f e c t s which are l i k e l y t o be e x p e r i e n c e d a t any proposed r e s e r v o i r are i n d i c a t e d , and the t e c h n i q u e a l l o w s f o r a more comprehensive a p p r a i s a l t o be made b e f o r e c o n s t r u c t i o n of dams than has been the case i n p a s t p r o j e c t s . Through e a r l y i d e n t i f i c a t i o n of secondary e f f e c t s , the framework a l s o p e r m i t s p l a n n i n g t o m i n i m i z e n e g a t i v e consequences or maximize p o s i t i v e consequences. 1 04 4. APPLICATION OF THE FRAMEWORK In t h i s chapter the impact i d e n t i f i c a t i o n framework i s a p p l i e d to a p a r t i c u l a r r e s e r v o i r c o n s t r u c t i o n p r o p o s a l . T h i s should serve two u s e f u l purposes. F i r s t , i t p r o v i d e s an example of a p p l i c a t i o n of the framework, i n d i c a t i n g i t s intended c a p a b i l i t i e s and l i m i t a t i o n s . Secondly, i t a l l o w s c o n s i d e r a t i o n of the u t i l i t y of the technique so f a r as i t s o b j e c t i v e of i n d i c a t i n g p o t e n t i a l impacts i s concerned, and i t p r o v i d e s a b a s i s f o r c o n s i d e r i n g v a r i o u s uses of the technique. T h i s c o n s i d e r a t i o n leads to an o v e r a l l e v a l u a t i o n , i n the ne xt, and f i n a l , chapter of the study. The p r o p o s a l to be used as an example i s one f o r a la r g e dam on the F r a s e r R i v e r at ffioran, approximately 220 mil e s upstream from the mouth of the r i v e r at Vancouver, B r i t i s h Columbia ( F i g u r e 5), The dam, i f b u i l t , would con-t r o l the flow from approximately 51,000 square miles of the Fr a s e r R i v e r ' s approximately 91,000 square mile watershed. With a t o t a l height of over 800 f e e t , the dam coul d develop an e f f e c t i v e head of 732 f e e t with i t s high water r e s e r v o i r l e v e l of 1520 f e e t . THE PROPOSED RESERVOIR f'loran Canyon has been r e c o g n i z e d fo r s e v e r a l decades as 1 05 1 06 a p o t e n t i a l s i t e f o r h y d r o e l e c t r i c development. In 1936 the B r i t i s h Columbia Department of Lands suggested t h r e e p o t e n t i a l s i t e s between L y t t o n and Quesnel f o r the c o n s t r u c t i o n of dams. Of t h e s e , the Moran s i t e was r e c o g n i z e d to have the g r e a t e s t p o t e n t i a l , w i t h 580 f o o t h i g h rock b l u f f s on e i t h e r s i d e of the r i v e r p r o v i d i n g the f o u n d a t i o n f o r a 1,640 f o o t l o n g dam s t r u c t u r e (B.C. Department of Lands, 1936), S e r i o u s c o n s i d e r a t i o n was g i v e n t o the Moran s i t e d u r -i n g the 1950*s by the Moran Power Development Company ( P o t t e r , 1957). The company proposed an 840 f o o t h i g h , 2,400 f o o t l o n g dam w i t h a head of 732 f e e t . The company was a d v i s e d by the p r o v i n c i a l government t h a t i n the event t h a t t hey s h o u l d a p p l y f o r the water l i c e n c e which would be r e q u i r e d f o r the development, a r e s e r v e on the L y t t o n t o Quesnel s t r e t c h of the F r a s e r R i v e r , would p r e v e n t i t s i s s u a n c e . F u r t h e r , under p r o v i n c i a l and f e d e r a l l e g i s l a t i o n , a p p r o v a l by v a r i o u s f i s h e r i e s a g e n c i e s would be r e q u i r e d b e f o r e the dam c o n s t r u c t i o n c o u l d commence. While the dam p r o p o s a l r e c e i v e d c o n s i d e r a t i o n over a p e r i o d of s e v e r a l y e a r s , c o n s t r u c t i o n was never s t a r t e d (Canada Department of the E n v i r o n m e n t , 1971a). The F e d e r a l - P r o v i n c i a l F r a s e r R i v e r Board s u g g e s t e d , but d i d not recommend, development of the ffloran Dam i n i t s i n v e s t i g a t i o n s l e a d i n g t o a 1963 r e p o r t on f l o o d p r e v e n t i o n 107 i n the F r a s e r V a l l e y between Hope and the d e l t a . As sugges-t e d , the dam would r a i s e the water l e v e l by some 740 f e e t t o the 1 ,520 f o o t e l e v a t i o n d u r i n g h i g h water p e r i o d s . At t h i s l e v e l an a r t i f i c i a l l a k e would be c r e a t e d e x t e n d i n g a p p r o x i -m a t e l y 170 m i l e s upstream t o a p o i n t a few m i l e s s o u t h of Q u e s n e l . With a 292 f o o t draw-down, the u s a b l e s t o r a g e c a p a c i t y was e s t i m a t e d a t 9,582,000 a c r e f e e t . A f i r m o u t -put c a p a c i t y of 1,191,000 k i l o w a t t s c o u l d be p r o v i d e d , based on 1946-47, which was a low water y e a r , though the average o u t p u t would be 1,689,000 k i l o w a t t s , and the i n s t a l l e d c a p a c -i t y would be 3,600,000 k i l o w a t t s (Canada Department of the E n v i r o n m e n t , 1971a). ' In 1971, w i t h i n i t i a t i o n of a s t u d y by the B.C. Energy Board on B r i t i s h Columbia's power r e q u i r e m e n t s t o 1985, s p e c u l a t i o n r o s e on a p o s s i b l e recommendation f o r d e v e l o p -ment of the Moran s i t e . For the p r e s e n t , however, d e v e l o p -ment seems u n l i k e l y i n l i g h t of p r o v i n c i a l P r e m i e r B e n n e t t ' s 28th March, 1972 statement t o the e f f e c t t h a t h i s government w i l l not b u i l d a Moran dam (The Sun, 28 March, 1972). Though c o n s t r u c t i o n thus appears h i g h l y u n l i k e l y i n the near f u t u r e , c o n s i d e r a t i o n of the p o t e n t i a l e f f e c t s of the dam w i l l not be a wasted e x e r c i s e . The s i t e w i l l c o n t i n u e t o be an a t t r a c t i v e one from a h y d r o e l e c t r i c e n g i n e e r i n g v i e w -p o i n t , and i t i s l i k e l y t o be c o n s i d e r e d f o r some time i n t o the f u t u r e . 1 08 CHARACTER OF THE PROPOSED RESERVOIR AREA B e f o r e a t t e m p t i n g c o m p l e t i o n of the impact i d e n t i f i c a -t i o n framework, some a t t e n t i o n must be g i v e n to the p r e s e n t c h a r a c t e r i s t i c s of the l a n d and water a r e a s which might be a f f e c t e d by c o n s t r u c t i o n o f a dam. In the case of the Moran p r o p o s a l , c o n s i d e r a t i o n must be g i v e n t o the F r a s e r R i v e r •basin and the c o a s t a l a r e a s i n t o which the r i v e r d r a i n s . Geography and h y d r o l o g y The E r a s e r R i v e r b a s i n o c c u p i e s an a r e a of 89,000 square m i l e s w i t h i n the s o u t h e r n h a l f of B r i t i s h C o l u m b i a , R i s i n g i n the Rocky M o u n t a i n s , the r i v e r f l o w s n o r t h w e s t w a r d a l o n g the Rocky Mountain Trench t o a p o i n t n o r t h e a s t of P r i n c e George, Here the r i v e r t u r n s westward, then s o u t h -west and s o u t h , t o f l o w p a s t P r i n c e George and southwards c u t t i n g d e e p l y i n t o the Nechako and F r a s e r p o r t i o n s of the I n t e r i o r P l a t e a u . Near L i l l o o e t , the r i v e r e n t e r s the Coast Mountains and f l o w s t h r o u g h a g r e a t gorge known as the F r a s e r Canyon t o Y a l e , a s m a l l community s i x t e e n m i l e s n o r t h of Hope, Mountains hem the F r a s e r - - t h e Cascades t o the e a s t , and the Coast Mountains t o the west, u n t i l i t f l o w s onto an a l l u v i a l f l o o d p l a i n near Hope, The f l o o d p l a i n widens over the l a s t 80 m i l e s t r e t c h , which i s known as the F r a s e r V a l l e y , and the r i v e r f l o w s i n t o the G u l f 1 09 of G e o r g i a t h rough a d e l t a a r e a i m m e d i a t e l y south of the C i t y of Vancouver. R i v e r f l o w i s h i g h l y v a r i a b l e , w i t h a 55 year average a t Hope e s t a b l i s h e d as 95,500 c u b i c f e e t per second. A h i g h f l o w of 536,000 c u b i c f e e t per second was r e c o r d e d on 31st May, 1948, and a low f l o w of 12,000 c u b i c f e e t per second on 8th J a n u a r y , 1916 (Canada Department of Energy, Mines and R e s o u r c e s , 1970). The 1948 f l o w r e s u l t e d i n e x t e n s i v e f l o o d damage to the F r a s e r V a l l e y . C l i m a t e and weather C l i m a t e of the E r a s e r R i v e r B a s i n v a r i e s c o n s i d e r a b l y from west to e a s t and from s o u t h to n o r t h . C o n t r o l i s e s t a b l i s h e d by west to e a s t moving p r e s s u r e systems. P r e -c i p i t a t i o n i s i n the 60 t o 100 i n c h per annum range from the r i v e r mouth t o Y a l e , Between Yale and L i l l o o e t , p r e c i p -i t a t i o n d e c r e a s e s r a p i d l y t o l e s s than 15 i n c h e s per annum, W i t h i n the I n t e r i o r P l a t e a u , p r e c i p i t a t i o n remains l i g h t , u n t i l near the e a s t e r n edge an i n c r e a s e i s brought about as a i r masses r i s e to pass over the Columbia and Rocky Mountains. Though a l o n g the i n l a n d c o u r s e of the main stream p r e c i p i t a t i o n i s g e n e r a l l y l i g h t , h i g h e r e l e v a t i o n s t h r o u g h o u t the watershed r e c e i v e between 30 and 100 i n c h e s a n n u a l l y . 1 1 0 D u r i n g the w i n t e r the n o r t h e r n p a r t o f the b a s i n l i e s under c o l d a r c t i c a i r , w i t h mean d a i l y t e m p e r a t u r e s i n January i n the range of z e r o t o 20 degrees F a h r e n h e i t . O c c a s i o n a l l y the c o l d a i r masses p e n e t r a t e south beyond the Canada-United S t a t e s boundary, though g e n e r a l l y J a nuary temp-e r a t u r e s i n the F r a s e r l / a l l e y a r e i n the h i g h 20's and low 30's. In the summer, h i g h p r e s s u r e a i r masses predomin-ate over the whole F r a s e r R i v e r B a s i n , w i t h mean d a i l y temp-e r a t u r e s i n J u l y i n the range of 60 t o 70 de g r e e s . E l e v a t i o n and the d i s t a n c e from the e f f e c t of c o a s t a l t e m p e r a t u r e moderation e x e r t c o n t r o l over the maximum t e m p e r a t u r e s r e a c h e d d u r i n g the summer. In the F r a s e r Canyon, and as f a r n o r t h as Q u e s n e l , maximum t e m p e r a t u r e s i n the h i g h 90's are c ommon. We qe t a t i on V e g e t a t i o n i n the b a s i n r e f l e c t s v a r i a t i o n s i n c l i m a t e and e l e v a t i o n . In the immediate v i c i n i t y of the proposed r e s e r v o i r , l i g h t p r e c i p i t a t i o n l e a d s t o an open canopy f o r e s t - g r a s s l a n d . T h i s grades from an a r i d ponderosa p i n e ( P i n u s ponderosa) and bunchgrass zone a t the s o u t h e r n end to a more mo i s t " C a r i b o o p a r k l a n d " zone a t the n o r t h e r n end which i n c l u d e s t r e m b l i n g aspen ( P o p u l u s t r e m u l o i d e s ) , C o t -tonwood ( P o p u l u s t r i c h o c a r p a ) . l o d g e p o l e p i n e ( P i n u s c o n t o r t a ) , and i n t e r i o r Douglas f i r ( P s e u d o t s u g a m e n z i e s i i v a r . q l a u c a ) . 111 The n o r t h e r n p o r t i o n of the b a s i n i s s u b a l p i n e f o r e s t , w i t h Engelmann spruce ( P i c e a e n q e I m a n n i) , l o d g e p o l e p i n e ( P i n u s  c o n t o r t a v a r . l a t i f o l i a ) , and mountain hemlock (Tsuga  m e r t e n s i a n a ) p r e d o m i n a t i n g . South and e a s t of P r i n c e George, as the F r a s e r f l o w s from the Rocky Mountain T r e n c h , the lower e l e v a t i o n v e g e t a t i o n of the "Columbia f o r e s t " r e f l e c t s heavy r a i n f a l l , w i t h western r e d cedar ( T h u j a  p i i c a t a ) , western hemlock (Tsuga h e t e r o p h y l l a ) , and western w h i t e p i n e ( P i n u s r n o n t i c o l a ) f o r m i n g a p a r t i a l l y c l o s e d canopy f o r e s t , V a r i e d forms of a l p i n e v e g e t a t i o n and s u b a l p i n e f o r e s t are found a t h i g h e r e l e v a t i o n s around the b a s i n ' s p e r i m i t e r (Chapman and T u r n e r , 1956), W i l d l i f e A v a r i e t y of w i l d l i f e s p e c i e s f i n d s u i t a b l e h a b i t a t s w i t h i n the F r a s e r R i v e r B a s i n , Large s p e c i e s i n c l u d e b l a c k -t a i l deer ( O d o c o i l e u s hemionus c o l u m b i a n u s - c o a s t , 0. h.  hemionus-mule), C a l i f o r n i a b i g h o r n sheep ( O v i s c a n a d e n s i s  c a l i f o r n i a n a ) , moose ( A l c e s a l c e s a n d e r s o n i ) , mountain c a r i b o u ( R a n g i f e r t a r a n d u s montanus), and e l k ( C e r v u s  c a n a d e n s i s n e l s o n i ) . A r e a l e x t e n t of these s p e c i e s i s b e s t d e s c r i b e d i n terms of w i n t e r i n g r a n g e , which i s c o n s i d e r a b l y c o n f i n e d by snow d e p t h , r e l a t i v e t o summer range. Deer are common t h r o u g h o u t the lower v a l l e y a r e a s , e x c e p t a l o n g the Rocky Mountain Trench and i n the F r a s e r Canyon, C a l i f o r n i a 1 1 2 b i g h o r n sheep are f a r l e s s common, b e i n g c o n f i n e d i n the w i n t e r t o l i m i t e d grounds n o r t h w e s t of L i l l o o e t and southwest of W i l l i a m s Lake. Moose are r e l a t i v e l y abundant t h r o u g h o u t the i n t e r i o r p o r t i o n of the b a s i n , w h i l e c a r i b o u and e l k are found o n l y i n the e a s t e r n p a r t of the b a s i n . Fur b e a r i n g a n i m a l s found w i t h i n the b a s i n i n c l u d e mink ( M u s t e l a v i s o n ) , muskrat (Ondatra z i b e t h i c a o s o y o o s e n s i s , 0. z. s p a t u l a t a ) , beaver ( C a s t o r c a n a d e n s i s s a q i t t a t u s ) , marten ( i f l a r t e s americana a b i e t i n o i d e s ) , and f i s h e r ( M a r t e s p e n n a n t i c o l u m b i a n a ) . These a n i m a l s may be found i n most w i l d l a k e s , or a l o n g c r e e k s and r i v e r s w i t h i n the b a s i n , and s u p p o r t a v i a b l e t r a p p i n g i n d u s t r y . A l s o p r e s e n t i n the b a s i n are g r i z z l y bear ( U r s u s a r c t o s h o r r i b i l i s ) , b l a c k bear ( U r s u s americanus cinnamomum) , wolves ( C a n i s l u p u s c o l u m b i a n u s ) , coyote ( C a n i s l a t r a n s i n c o l a t u s , C.' 1. l e s t e s ) , fox (Wulpes f u l v a ? ) , cougar ( F e l i s c o n c o l o r m i s s o u l e n s i s , F. c. o r e q o n e n s i s ) , l y n x (Lynx r u f u s p a l l e s c e n s ) , and a v a r i e t y of s m a l l r o d e n t s . (Cowan and G u i g u e t , 1 9 6 5 ) . Anadromous F i s h The F r a s e r R i v e r B a s i n i s an i m p o r t a n t spawning a r e a f o r s a l m o n o i d f i s h e s i n c l u d i n g " ... major p o p u l a t i o n s of sockeye and c h i n o o k salmon, s i g n i f i c a n t numbers of s t e e l h e a d t r o u t and a few p i n k salmon. The a d u l t s of these s p e c i e s m i g r a t e 113 upstream to spawning grounds l o c a t e d on the main stem and v a r i o u s t r i b u t a r i e s , and the f r y or smolts migrate downstream to the sea. In a d d i t i o n , very l a r g e numbers of sockeye, chinook, coho, pink and chum salmon and s t e e l h e a d t r o u t u t i l i z e the F r a s e r R i v e r and i t s t r i b u t a r i e s f o r f e e d i n g , t r a n s p o r t a t i o n or spawning downstream from Oloran," (Canada, Department of the Environment, 1971a, p. 16). Upstream m i g r a t i o n p e r i o d s f o r sockeye and pink salmon at filoran Canyon are from l a t e June to mid-October, while downstream m i g r a t i o n i s from e a r l y March to l a t e June. If a l l other s p e c i e s are c o n s i d e r e d , m i g r a t i o n i s i n progress at v i r t u a l l y a l l times of the year. Access i n the proposed r e s e r v o i r area Some of the major impacts of the ffloran Dam r e s e r v o i r w i l l be f e l t i n the area inundated by, and immediately adjacent t o , the r e s e r v o i r . T h i s compromises a narrow s t r i p of land some 170 m i l e s l o n g , but seldom more than a mile or two wide, s t r e t c h i n g between the Moran r a i l w a y s i d i n g at the south end and K e r s l e y at the north end. Access throughout the area i s good. The B r i t i s h Columbia Railway i s approximately a mile from the dam s i t e at an e l e v a t i o n about 1,000 f e e t higher than the r i v e r . The Trans-Canada Highway passes through L y t t o n , 40 m i l e s south of L i l l o o e t , and a secondary highway j o i n s the two c e n t r e s . An a l l weather loose s u r f a c e road connects L i l l o o e t to P a v i l l i d n 114 which i s twenty-one m i l e s to the n o r t h , and t h r e e m i l e s s o u t h o f ffloran. L i l l o o e t , a community of some 1 , 5 0 0 p e r s o n s , and C l i n t o n , a s m a l l e r community t o the n o r t h e a s t , are both a p p r o x i m a t e l y t w e n t y - f o u r m i l e s from the dam s i t e . Upstream from the dam s i t e t h e r e i s a f a i r l y good a c c e s s a l o n g the r i v e r ' s e a s t bank i n .the form of a l l weather roads and t r a i l s . A c cess t o the west s i d e of the r i v e r may be g a i n e d by b r i d g e a t L i l l o o e t and near W i l l i a m s L a k e , and by c a b l e c a r and c a b l e f e r r y a t a number of p o i n t s between P a v i l l i o n and A l e x a n d r i a . T r a n s p o r t a t i o n f a c i l i t i e s p a r a l l e l l i n g the r i v e r are l e s s d e v e l o p e d on the west s i d e than on the e a s t , however an a l l weather road runs from R i s k e Creek ( t w e n t y - t h r e e m i l e s southwest of W i l l i a m s Lake) t o Q u e s n e l . Economic s t r u c t u r e of the proposed r e s e r v o i r a r e a The main i n d u s t r i e s i n the a r e a near the F r a s e r R i v e r and between L i l l o o e t and Quesnel are f o r e s t r y and a g r i c u l t u r e . Commercial f o r e s t c o v e r w i t h i n the a c t u a l r e s e r v o i r b a s i n i s m i n i m a l . L i k e w i s e , m i n i m a l amounts of a g r i c u l t u r a l l a n d are w i t h i n the proposed r e s e r v o i r b a s i n because of the s t e e p n e s s of i t s . s i d e s . C a t t l e r a n c h i n g , which i s c a r r i e d out t h r o u g h o u t the C a r i b o o a r e a would not be s i g n i f i c a n t l y a f f e c t e d by the r e s e r v o i r . Only a s m a l l number of homes and farms are l o c a t e d 115 above Moran, and below the 1,520 f o o t c o n t o u r , the e l e v a t i o n of h i g h water i n the proposed impoundment. R e l o c a t i o n of the r e s i d e n t s of these homes would, of c o u r s e , be n e c e s s a r y . * # * T h i s c o m p l e t e s a b r i e f s u r v e y of the c h a r a c t e r i s t i c s of the a r e a which would be a f f e c t e d i n the event t h a t a dam i s c o n s t r u c t e d a t Moran Canyon, The amount of d e t a i l p r o -v i d e d here i s adequate f o r i n i t i a l i d e n t i f i c a t i o n of p o t e n t -i a l i m p a c t s , and c o m p i l a t i o n of the framework may be u n d e r t a k e n w i t h o u t g r e a t e r d e t a i l . Once p o t e n t i a l i m p a c t s are thus i n d i c a t e d , o t h e r t e c h n i q u e s s h o u l d be a p p l i e d t o p r e d i c t t h e i r p r o b a b i l i t y , and t o e v a l u a t e t h e i r i m p o r t a n c e . POTENTIAL IMPACTS OF THE MORAN RESERVOIR An impact i d e n t i f i c a t i o n framework has been completed f o r the Moran Dam p r o p o s a l ( F i g u r e 7, p o c k e t ) . Based on the m a t e r i a l which has been p r o v i d e d i n the p r e c e d i n g pages, the framework has been marked t o i n d i c a t e p o t e n t i a l e f f e c t s and t h e i r degree of p r o b a b i l i t y . T h i s l e a d s to the f o l l o w i n g s u b j e c t i v e d i s c u s s i o n of some of the f a c t o r s i n d i c a t e d by the framework. Reasons f o r e x p e c t i n g v a r i o u s e f f e c t s are mentioned a l o n g w i t h m a t e r i a l from s e v e r a l s t u d i e s which have a l r e a d y been c a r r i e d o u t , and which complement the framework. 116 C o n s t r u c t i o n of the Dam C o n s t r u c t i o n of a l a r g e dam a t Moran Canyon would r e q u i r e an i n f l u x of s e v e r a l hundred c o n s t r u c t i o n w o r k e r s , a l o n g w i t h v a r i o u s s e r v i c e and s u p p o r t i n d u s t r i e s , Whether L i l l o o e t or C l i n t o n i s used as the c e n t r e t o accommodate t h i s p o p u l a t i o n , or an a l t o g e t h e r new t o w n s i t e i s b u i l t , u n d e s i r -a b l y h i g h p o p u l a t i o n d e n s i t i e s are i m p r o b a b l e . Though development of slum a r e a s by an i n f l u x of u n s k i l l e d and unemployed persons i s a l s o u n l i k e l y , p l a n n i n g w i l l be r e q u i r e d . Permanent houses are u n l i k e l y to accommodate a l l those who come to work on the dam or i n the a r e a , M o b i l e homes are a p r o b a b l e consequence. These can p r o v i d e a t t r a -c t i v e accommodation, however, a t t e n t i o n must be g i v e n t o p r o v i d e a s u i t a b l e l o c a t i o n and s e r v i c e s f o r the u n i t s , i f s a n i t a t i o n and a e s t h e t i c s are to be m a i n t a i n e d a t a h i g h l e v e l . Improved a c c e s s t o the Moran a r e a , and p u b l i c i t y which i s l i k e l y t o accompany a- dam b u i l d i n g p r o j e c t w i t h i n a few hours d r i v i n g time of a major p o p u l a t i o n c e n t r e , w i l l a t t r a c t l a r g e numbers of r e c r e a t i o n a l v i s i t s . ' C o n s i d e r a t i o n s h o u l d be g i v e n t o i n c r e a s i n g camping f a c i l i t i e s i n the a r e a , s u p p l e m e n t i n g the e x i s t i n g P r o v i n c i a l Government campsite a t Marble Canyon, P o s s i b l e c o n f l i c t s between campers and l a n d h o l d e r s , and l i t t e r i n g and overuse of 117 a t t r a c t i v e roadside p o i n t s may thus be minimized. D i s r u p t i o n of l o c a l p o p u l a t i o n Only a small number of homes would r e q u i r e r e l o c a t i o n i f the nioran Dam i s b u i l t . Adequate a t t e n t i o n to r e l o c a t i o n may be expected, and though readjustment s t r e s s e s f o r those i n v o l v e d are unavoidable, the process i s l i k e l y to r e c e i v e adequate a t t e n t i o n to ensure that these w i l l be minimized. I n i t i a l r e s e r v o i r f i l l i n g As the r i v e r v a l l e y i s narrow and steep s i d e d f o r the e n t i r e l e g n t h of the proposed r e s e r v o i r , s t r a n d i n g of animals on r a i s e d ground s u r f a c e s by r i s i n g water would be minimal. Small rodents would be d i s p l a c e d from, h a b i t a t s along the r i v e r banks and benches by impounded waters, however these s p e c i e s are not dependent on h a b i t a t s of l i m i t e d e x t e n t , and t h e i r displacement would b r i n g only minor p o p u l a t i o n readjustment, V e g e t a t i o n i n the proposed r e s e r v o i r basin i s l i m i t e d and minimal c l e a r i n g would be r e q u i r e d . C o n s i d e r a t i o n of e u t r o p h i c a t i o n and i t s consequences would be r e q u i r e d d u r i n g the p l a n n i n g stages. A b s o r p t i o n and seepage a l s o r e q u i r e f u r t h e r c o n s i d e r a t i o n by g e o l i g i s t s and engineers though i t 11 8 has been s u g g e s t e d t h a t the r e s e r v o i r bed i s i m p e r v i o u s and i n s o l u b l e ( F r a s e r R i v e r Board, 1956, p, £103). C h a r g i n g of a q u i f e r s , l e a d i n g t o the s u p p l e m e n t a t i o n of s u r f a c e water s u p p l y downstream from the dam, c o u l d be h i g h l y d e s i r a b l e f o r a g r i c u l t u r a l p u r p o s e s . C r e a t i o n of a r t i f i c i a l l a k e s With the c r e a t i o n of a l a k e b e h i n d a dam a t ffioran , t h e r e are no a n i m a l s p e c i e s which appear t o be endangered by l o s s of c r i t i c a l h a b i t a t . W i n t e r ranges f o r the C a l i f o r n i a b i g -horn sheep, ( O v i s canade n i s C a l i f o r n i a ) , would be s l i g h t l y r educed at the c o n f l u e n c e of the C h i l c o t i n and F r a s e r R i v e r s i n the R i s k e Creek a r e a . T h i s f a c t o r might be s e r i o u s when combined w i t h o t h e r t h r e a t s to the r e l a t i v e l y s m a l l p o p u l a t i o n o f the s p e c i e s . As i n d i c a t e d i n Chapter 2 , p r e d i c t i o n of the e x t e n t of s e i s m i c a c t i v i t y i n d u c e d by f i l l i n g the r e s e r v o i r s i s i m p p s s i b l e . A major, though i n a c t i v e f a u l t c r o s s e s the r i v e r 1 downstream from the dam s i t e , and t h e r e are a number of o t h e r major f a u l t s i n the F r a s e r Canyon a r e a . Heavy s e d i m e n t a t i o n of the filoran R e s e r v o i r i s p r o b a b l e , a s the r i v e r c a r r i e s a heavy s i l t l o a d . I t i s e s t i m a t e d t h a t 19,000,000 tons would be d e s p o s i t e d a n n u a l l y i n the r e s e r v o i r 119 ( P r e t i o u s , 1972). Loss of t h i s l o a d w i l l l e a d t o i n c r e a s e d e r o s i o n by the F r a s e r R i v e r below the d a m s i t e , both i n the canyon and i n the v a l l e y u n t i l a new s t a b i l i z a t i o n o c c u r s . A f t e r t h i s t i m e , reduced sediment l o a d i n the lower F r a s e r may a l l o w c o n s t r u c t i o n of a c h a n n e l s u i t a b l e f o r n a v i g a t i o n of deep sea s h i p s as f a r i n l a n d as C h i l l i w a c k . There w i l l be a l o s s of s i l t a d d i t i o n t o F r a s e r v a l l e y f a r m l a n d as i r r i g a t i o n w aters w i l l c a r r y a reduced s i l t l o a d , The e f f e c t of t h i s l o s s , and the e f f e c t of the l o s s of s i l t i n the e s t u -a r i n e a r e a remains s p e c u l a t i v e . E v a p o r a t i o n from the r e s e r v o i r c o u l d be q u i t e e x t e n s i v e d u r i n g h o t , dry summer p e r i o d s and r e s u l t i n g h u m i d i t y combined w i t h t e m p e r a t u r e m o d i f i c a t i o n would cause a t l e a s t minor c l i m a t i c change. These changes would be r e f l e c t e d by v e g e t a -t i o n i n the a r e a i n the v i c i n i t y of the r e s e r v o i r . P r e c i p i t a -t i o n of e v a p o r a t e d water would be u n l i k e l y u n t i l a i r masses are moved a c r o s s the I n t e r i o r P l a t e a u , and a t t h i s d i s t a n c e any d i f f e r e n c e i n p r e c i p i t a t i o n i s not l i k e l y t o s i g n i f i c a n t l y a f f e c t v e g e t a t i o n . Thermal s t r a t i f i c a t i o n of the a r t i f i c i a l l a k e i s most l i k e l y , A depth of 700 f e e t near the dam w i l l p e r m i t e s t a b -l i s h m e n t of c o n s i d e r a b l e t emperature g r a d i e n t between s u r f a c e and bottom w a t e r s d u r i n g the warm summer months, Whether or not e u t r o p h i c a t i o n or o t h e r b i o l o g i c a l a c t i v i t y would l e a d t o 120 h y p o l i n m i o n oxygen d e p l e t i o n and subsequent r e l e a s e of f o u l e d waters r e q u i r e s f u r t h e r s t u d y . The r e s e r v o i r i s u n l i k e l y to promote growth of any d i s e a s e v e c t o r s of s i g n i f i c a n c e t o man. E x t e n s i v e draw-down however, may l e a d to b r e e d i n g of m o s q u i t o e s , which are a l r e a d y a n u i s a n c e i n the a r e a . The F r a s e r R i v e r Board's ffioran Dam p r o p o s a l i n v o l v e s draw-down to a maximum of 292 f e e t below h i g h water l e v e l . In a d d i t i o n t o p r o v i d i n g a h a b i t a t f o r b r e e d i n g of i n s e c t s , t h i s e x t e n t of.draw-down would s e r i o u s l y l i m i t the r e c r e a t i o n a l use of the l a k e . Downstream f l o w changes I f a dam i s b u i l t i n the ffloran Canyon downstream f l o w on F r a s e r R i v e r w i l l be c o n s i d e r a b l y s t a b i l i z e d . T h i s may l e a d t o advantages i n n a v i g a t i o n , when i n c o m b i n a t i o n w i t h the reduced s i l t d e p o s i t i o n , f l o w s t a b i l i z a t i o n w i l l p e r m i t deep sea n a v i g a t i o n i n l a n d as f a r as C h i l l i w a c k , and year round use of s h a l l o w d r a f t b o a t s upstream t o Hope or Yale ( P r e t i o u s , 1972). Changes i n e s t u a r i n e s a l i n i t y w i l l be towards the d i r e c t i o n of s t a b i l i z a t i o n a t a year round l e v e l , w i t h a r e d u c t i o n of the h i g h d i l u t i o n of s a l t b y . f r e s h water a t h i g h f l o w i n the s p r i n g , a n d the low d i l u t i o n of low f l o w i n the w i n t e r . 1 21 Anadromous f i s h The e f f e c t of the Moran Dam on anadromous s a l m o n o i d f i s h s p e c i e s has had c o n s i d e r a b l e a t t e n t i o n , and i t i s i n t h i s F i e l d t h a t t h e r e i s l e a s t u n c e r t a i n t y as t o the dam's consequences. A 1971 r e p o r t on f i s h e r i e s problems r e l a t e d to the Moran Dam c o n c l u d e s : "1, The minimum e f f e c t of Moran Dam would be the d e s t r u c t i o n of a l l salmon and s t e e l h e a d t r o u t p o p u l a -t i o n s t h a t spawn upstream from the dam. 2. I t i s p r o p a b l e t h a t the c a t c h e s i n c o m m e r c i a l , s p o r t and I n d i a n food f i s h e r i e s of salmon and s t e e l -head t r o u t p o p u l a t i o n s t h a t u t i l i z e the F r a s e r R i v e r and i t s t r i b u t a r i e s downstream from Moran would be reduced by about 50 p e r c e n t due t o e n v i r o n m e n t a l changes i n the r i v e r e s t u a r y . " (Canada Department of the E n v i r o n m e n t , 1971a, p. 197). Flow r e d u c t i o n a t c r i t i c a l p e r i o d s of the y e a r , t e m p e r a t u r e changes i n the t e m p e r a t u r e of downstream water, and problems i n h a n d l i n g f i s h a t the dam w i t h i n the r e s e r v o i r would a l l c o n t r i b u t e t o the h i g h l o s s of f i s h . *• * * In t h i s b r i e f example of the a p p l i c a t i o n of i d e n t i f i c a t i o n framework, i t has become apparent the impact t h a t the 122 technique can be put to good use. The p o t e n t i a l secondary e f f e c t s of c o n s t r u c t i o n and o p e r a t i o n of the dam and r e s e r -v o i r system appear to cover a broader range than that which has g e n e r a l l y been expected. By p u t t i n g the cause and e f f e c t r e l a t i o n s h i p s i n t o the l o g i c a l " i m p a c t - m u l t i p l e order c o n s e q u e n c e - f i n a l consequence" format, i t i s p o s s i b l e f o r e i t h e r expert or -layman to understand why the r e s e r v o i r could cause c e r t a i n e f f e c t s . The l a c k of c e r t a i n t y about many of the p o t e n t i a l consequences of c o n s t r u c t i o n of the dam at fnoran Canyon c l e a r l y i n d i c a t e s the need f o r c o n s i d e r -able s e r i o u s and d e t a i l e d study before any d e c i s i o n to b u i l d the dam i s made. 1 23 5. DISCUSSION AND CONCLUSIONS An impact i d e n t i f i c a t i o n framework f o r l a r g e r e s e r v o i r s has been d e v e l o p e d w i t h i n t h i s s'tudy. The framework uses a stepped m a t r i x approach to i d e n t i f y " o b j e c t i v e s " , "methods of e x e c u t i o n " , " i m p a c t s " , and " m u l t i p l e o r d e r consequences". W i t h i n the range of the c l a s s e s of f a c t o r s which are c o n s i d -e r e d , the p r i n c i p a l secondary e f f e c t s which have been e x p e r i e n -ced a t a r e p r e s e n t a t i v e s e l e c t i o n of w o r l d r e s e r v o i r s have been i n c l u d e d . F u r t h e r a d d i t i o n s t o the framework w i l l s e r v e t o add t o i t s c omprehensiveness and improve i t s u t i l i t y . As a r e l a t i v e l y new approach t o the p r e - e v a l u a t i o n i d e n t i f i c a t i o n of f a c t o r s which s h o u l d be i n c l u d e d i n e v a l u a -t i o n p r o c e d u r e s , the t e c h n i q u e shows c o n s i d e r a b l e p o t e n t i a l . Why i s an impact i d e n t i f i c a t i o n approach n e c e s s a r y i n the p l a n n i n g o f c o n s t r u c t i o n o f dams and c r e a t i o n o f r e s e r v o i r s ? We need l o o k no f a r t h e r than r e c e n t h i s t o r y f o r an answer to t h i s q u e s t i o n . V i r t u a l l y e v e r y l a r g e r e s e r -v o i r p r o j e c t which has been c o n s t r u c t e d has l e d t o e f f e c t s o t h e r than the achievement of i t s p r i m a r y o b j e c t i v e s . These e f f e c t s may be c l a s s i f i e d as i m p a c t s and r e s u l t a n t consequences. They d i r e c t l y and i n d i r e c t l y a f f e c t man, c a u s i n g s u f f e r i n g , economic l o s s , and i n some ca s e s u n a n t i c -i p a t e d b e n e f i t s . They a l s o l e a d t o f e e d b a c k s , or r e d u c t i o n of the p r o j e c t ' s a b i l i t y t o meet i t s p r i m a r y o b j e c t i v e s . 1 24 Too o f t e n , i t would seem, f a i l u r e to a n t i c i p a t e the i m p a c t s of a l a r g e r e s e r v o i r p r o j e c t has m i s l e d a s s u m p t i o n s on the p r o j e c t ' s o v e r a l l f e a s i b i l i t y . R e c o g n i t i o n of i m p a c t s d u r i n g e a r l y p l a n n i n g s t a g e s may thus p r e s e n t a b e t t e r b a s i s f o r comparison between the d e s i r a b i l i t y of d i f f e r e n t a l t e r n a t -i v e s f o r a c h i e v i n g s i m i l a r o b j e c t i v e s . R e c o g n i t i o n of i m p a c t s and t h e i r consequences b e f o r e they occur a l s o p e r m i t s p r e p a r a t i o n f o r m i n i m i z i n g n e g a t i v e e f f e c t s and m a x i m i z i n g p o s i t i v e ones. A second q u e s t i o n may be posed c o n c e r n i n g the c e r t a i n t y w i t h which secondary e f f e c t s can be p r e d i c t e d . Is i t pos-s i b l e d u r i n g p l a n n i n g s t a g e s t o p r e d i c t , w i t h a h i g h degree of c e r t a i n t y , the sequence and magnitude of a l l i m p a c t s and t h e i r consequences. Of c o u r s e , i t i s n o t . Though some e f f e c t s , such as those of a h i g h dam on upstream spawning anadromous f i s h s p e c i e s , are p r e d i c t a b l e w i t h a b s o l u t e c e r -t a i n t y , the b a s i s f o r p r e d i c t i n g o t h e r e f f e c t s i s l e s s c e r t a i n . The e f f e c t of a dam on p a t t e r n s of downstream e r o s i o n and d e p o s i t i o n , f o r example, can be p r e d i c t e d , but t h e r e w i l l be a lower degree of c e r t a i n t y about the p r e d i c t i o n . Consequences such as the e f f e c t of a mass of r e s e r v o i r water on the e a r t h ' s c r u s t cannot be p r e d i c t e d w i t h any c e r t a i n t y a t a l l . Though u n c e r t a i n t y i s i n h e r e n t i n the p r o c e s s of p r e d i c t i n g the c o u r s e of consequences stemming from r e s e r v o i r development, the impact i d e n t i f i c a t i o n 1 25 framework t e c h n i q u e a l l o w s f o r i d e n t i f i c a t i o n of p o t e n t i a l consequences. F u r t h e r a n a l y s i s may l e a d to assessment of the p r o b a b i l i t y and magnitude of consequences, and b r i n g the a n a l y s i s to a stage a t which i t i s p o s s i b l e t o e x p r e s s consequence p o t e n t i a l s i n terms such a s : "low p r o b a b i l i t y -low magnitude", "low p r o b a b i l i t y - h i g h magnitude", " h i g h p r o b a b i l i t y - l o w magnitude", and " h i g h p r o b a b i l i t y - h i g h magnitude". T h i s p r o c e s s can be q u i t e v a l u a b l e d u r i n g p l a n -n i n g s t a g e s , as i t r a p i d l y i n d i c a t e s p o i n t s a t which f e a s -i b i l i t y s t u d i e s are weakened by u n c e r t a i n t y ; and c o n s e q u e n t l y the v a l u e of e x p e c t e d b e n e f i t s may be c o n s i d e r e d r e l a t i v e t o the e f f e c t s of "low p r o b a b i l i t y - h i g h magnitude" consequences. Thus, a l t h o u g h t h e r e i s not a h i g h l e v e l of c e r t a i n t y about the o c c u r r e n c e of some p o t e n t i a l e f f e c t s a t p a r t i c u l a r r e s e r v o i r p r o j e c t s , the u t i l i t y of the impact i d e n t i f i c a t i o n framework i s not r e d u c e d . C o n s i d e r a t i o n s h o u l d be g i v e n t o the ways i n which the impact i d e n t i f i c a t i o n framework may be put t o use. The p r i m a r y o b j e c t i v e i s , of c o u r s e , i d e n t i f i c a t i o n of i m p a c t s and consequences d u r i n g the p l a n n i n g s t a g e s f o r a l a r g e r e s e r v o i r p r o j e c t s . For t h i s purpose the framework s h o u l d be of v a l u e t o a g e n c i e s u n d e r t a k i n g the p l a n n i n g of r e s e r -v o i r s , and t o b o d i e s which must pass p l a n s f o r such r e s e r v o i r s . With i t s impact-consequence f o r m a t , i t w i l l a l s o be u s e f u l f o r c o n c e p t u a l i z a t i o n of l o g i c a l sequences 1 25 f o r i n v e s t i g a t i v e s t u d i e s . In t h a t many d i f f e r e n t phenomena may l e a d t o i d e n t i c a l consequences, the framework c o u l d be put t o use i n c o n c e p t u a l i z a t i o n of models to be used f o r p r e d i c t i v e or e x p e r i m e n t a l p u r p o s e s . P u b l i c e d u c a t i o n i s a n o t h e r use to which the framework may be a p p l i e d . P l a n n e r s , t h r o u g h the p l a n n i n g p r o c e s s , have a p r i m a r y r e s p o n s i b i l i t y t o i n d i c a t e to the p u b l i c or t h e i r r e p r e s e n t a t i v e s , the consequences of v a r i o u s forms of a c t i o n f o r a c h i e v i n g an o b j e c t i v e . For a pers o n u n f a m i l i a r w i t h r e s e r v o i r s , the r e l a t i o n s h i p between a l a r g e man-made l a k e i n some remote a r e a which he has never seen, and the o f f - s h o r e f i s h i n g i n d u s t r y , the spread of d i s e a s e , the f a c i l i t a t i o n of n a v i g a t i o n , or s i m i l a r consequences, may be c o m p l e t e l y u n c l e a r . The framework i l l u s t r a t e s t hese r e l a t i o n s h i p s i n a r e l a t i v e l y s i m p l e , s t e p by s t e p manner. I t s use can i n c r e a s e p u b l i c u n d e r s t a n d i n g of the consequen-ces of a c t i o n s u ndertaken on t h e i r b e h a l f , thus l e a d i n g t o a more s o l i d f o u n d a t i o n f o r d e c i s i o n s l e a d i n g t o the c r e a t i o n of r e s e r v o i r s . As a f i n a l p o t e n t i a l use to which the framework may be a p p l i e d , t h e r e i s o p p o r t u n i t y f o r i n c r e a s i n g c r e d i b i l i t y between d e c i s i o n makers and t h e i r p l a n n i n g a g e n c i e s , and v a r i o u s advocate groups and i n d i v i d u a l s . Open use of the impact i d e n t i f i c a t i o n framework w i l l a l l o w r e a l i s t i c 1 27 a p p r a i s a l by both p r o p o n e n t s and opponents of proposed p r o j e c t s . I t a l l o w s f o r s p e c i f i c c r i t i c i s m where t h e r e a re d i f f e r e n c e s of o p i n i o n as t o the o c c u r r e n c e of c e r t a i n s e c ondary e f f e c t s , or as t o t h e i r magnitude and e v a l u a t i o n . Thus, by i m p r o v i n g the l e v e l of u n d e r s t a n d i n g and communications between those w i t h d i f f e r e n t o p i n i o n s , the framework may prove t o be q u i t e v a l u a b l e . Two s u g g e s t i o n s are made f o r improvements t o the framework impact i d e n t i f i c a t i o n approach f o r l a r g e r e s e r v o i r s . F i r s t , f u r t h e r s t u d y s h o u l d be a p p l i e d t o ensure the h i g h e s t p o s s i b l e degree of co m p r e h e n s i v e n e s s . Though, i n i t s p r e s e n t form, the framework w i l l i n d i c a t e most of the p o t e n t -i a l i m p a c t s a t any proposed r e s e r v o i r s i t e , i n e v i t a b l e o m i s s i o n s remain t o be f i l l e d - i n . A second r e f i n e m e n t c o u l d l e a d t o a l e s s cumbersome framework f o r m a t . T h i s would i n v o l v e s e p a r a t i o n of i m p a c t s which are common t o a l l r e s e r v o i r s from those which are common o n l y t o a s p e c i f i c type of r e s e r v o i r i n a s p e c i f i c c l i m a t i c a r e a . Then the pr o c e d u r e would i n v o l v e c o m p l e t i o n of the framework common to a l l r e s e r v o i r s p l u s one of a c h o i c e of o t h e r frameworks d e a l i n g s p e c i f i c a l l y w i t h s i t u a t i o n s such a s : " t r o p i c a l h i g h dams", " t r o p i c a l e a r t h f i l l dams", "temperate h i g h dams", and "temperate e a r t h f i l l dams". T h i s more manage-a b l e format would not reduce the framework's c o m p r e h e n s i v e n e s s . 1 28 In c o n c l u s i o n , the d e s i r e d check l i s t form of impact i d e n t i f i c a t i o n frameujcrk has been d e v i s e d . The stepped m a t r i x approach to impact i d e n t i f i c a t i o n i s sound and l o g i c a l , and the "Impact I d e n t i f i c a t i o n Framework f o r Large R e s e r v o i r s " appears to have adequate p o t e n t i a l f o r s e r i o u s a p p l i c a t i o n to r e s e r v o i r development i n v e s t i g a t i o n s . 1 29 B I B L I O G R A P H Y Abu-Wafa, Taker and A z i z Hanna L a b i b 1970 I n v e s t i g a t i o n s and O b s e r v a t i o n s of Seepage L o s s e s from the Aswan High Dam R e s e r v o i r . S e e I n t e r n a t i o n a l Commission on Large Dams, pp. 1047-1070. Aksoy, Sahap 1970 R i v e r Bed D e g r a d a t i o n Downstream of Large Dams. See I n t e r n a t i o n a l Commission on Large Dams, pp. 835-844. Apted, F.I.C, W.M. Ormerod, D.P. Smyly, 3.UJ. S t r o n a c h and 1963 E.Z. Szlamp A Comparative Study of Epedemiology of Endemic Rhodesian S l e e p i n g S i c k n e s s i n D i f f e r e n t P a r t s of A f r i c a . J o u r n a l of T r o p i c a l M e d i c i n e and Hyg i e n e , V o l , 66, No. 1, A s i b e y , E.O.A. 1969 W i l d l i f e i n the V o l t a B a s i n , See Obeng, pp. 366-372. Bardach, John 1964 A N a t u r a l H i s t o r y of the R i v e r . Harper and Row, P u b l i s h e r s , B a r n i n g , K and J . Banxon 1969 P o s s i b l e S e d i m e n t a t i o n and S e i s m i c E f f e c t s on the V o l t a Lake. See Obeng, pp. 83-90 B e r k o w i t z , D.A. and A.M. S q u i r e s ( e d i t o r s ) . 1971 Power G e n e r a t i o n and E n v i r o n m e n t a l Change, The M.I.T. P r e s s . B e r t h i e r , A., J . Cabanne, G. D o u i l l e t , A. Lambert and J . Rand 1970 Quelques problemes poses par l a c r e a t i o n de b a r r a g e s sur un r i v i e r e t r a n s p o r t a n t des d e b i t s s o l i d e s . See I n t e r n a t i o n a l Commission on Large Dams, pp. 489-506. 3 r i t i s h C o l u m b i a , Department of Lands 1936 Water Powers, E r a s e r R i v e r , B r i t i s h C o l u m b i a , Canada. Brown, Leonard H, 1966 The M u l t i - p u r p o s e Use of R e s e r v o i r s . See Lowe-M c C o n n e l l , pp. 183-188. 1 30 B u l l a r d , O r a l 1968 C r i s i s on the Columbia. The Touchstone P r e s s , P o r t l a n d , Oregon. Canada, Department of Energy, inline s and Resources 1970 S u r f a c e Water D a t a , B r i t i s h C o l u m b i a , Water Year 1967. Queen's P r i n t e r , Ottawa. Canada, Department of the Environment and I n t e r n a t i o n a l 1971a P a c i f i c Salmon F i s h e r i e s Commission F i s h e r i e s Problems R e l a t e d t o the Moran Dam on the F r a s e r R i v e r . Canada, Environment Canada 1971 b : Peace-Athabasca D e l t a P r o j e c t , The Problems, P r o p o s a l s and A c t i o n s Taken. C a r l , G. C l i f f o r d , W.A. Clemens and C.C. L i n d s e y 1967 The Fr e s h - w a t e r F i s h e s o f . B r i t i s h Columbia. B r i t i s h Columbia P r o v i n c i a l Museum Handbook No. 5, F o u r t h E d i t i o n , Queen's P r i n t e r , V i c t o r i a . Chapman, J.D. and D.B. Turner ( e d i t o r s ) 1956 B r i t i s h Columbia A t l a s of R e s o u r c e s , B r i t i s h Columbia N a t u r a l R esources C o n f e r e n c e . Church, R . J , H a r r i s o n 1968 Dams i n A f r i c a — A G e o g r a p h i c a l View. See Rubin and Warren, pp. 1-12. Clements, Frank 1959 K a r i b a , The 5 t r u g g l e With the R i v e r God. Methuen and Company L i m i t e d , London, C o l e , Monica M, 1960 The K a r i b a P r o j e c t , Geography, V o l , 45, pp, 98-105. Conway, G.R.G. 1915 Water Powers of Canada, P r o v i n c e of B r i t i s h Columbia. Dominion Water Powers B r a n c h , Department of the I n t e r i o r , Ottawa. C o u l t e r , G.W. 1967 What's Happening a t K a r i b a ? New S c i e n t i s t , V o l . 36, No. 557, pp, 750-752, Cowan,- Ian McTaggart and C h a r l e s J . Guiguet 1965 The Mammals of B r i t i s h Columbia, B r i t i s h Columbia P r o v i n c i a l Museum Hamdbook No, 11, T h i r d E d i t i o n , Queen's P r i n t e r , V i c t o r i a . 1 31 C r o n i n , L. Eugene 1967 The Role of Man i n E s t u a r i n e P r o c e s s e s . See L a u f f . De-Heer Amissah, A.N. 1969 Some P o s s i b l e C l i m a t i c Changes That May be Caused by the V o l t a Lake. 5ee Obeng, pp. 73-82, Dorcey, Anthony H,, I.K, Fox and R.J. Fox 1972 Management of Water Resources Common to More than One N a t i o n a l J u r i s d i c t i o n . t o be p r e s e n t e d a t the U n i t e d N a t i o n s Conference on the Human E n v i r o n m e n t , S t o c k h o l m , 1972. Do u g l a s , 3 a r b a r a 1966 " d i s c u s s i o n " . See Lowe-McConnell, p. 50. Ewer, D. W. 1966 B i o l o g i c a l I n v e s t i g a t i o n s of the V o l t a L a k e , May 1964 t o May 1965. See L o i u e-McConnell, pp. 21-30. F a r v a r , M. Ta g h i 1969 S p e c i a l Supplements The Unforeseen I n t e r n a t i o n a l E c o l o g i c Soomerange. N a t u r a l H i s t o r y , F e b r u a r y . F r a s e r R i v e r B a s i n D o m i n i o n - P r o v i n c i a l Board 1952 F o u r t h Annual R e p o r t . 1953 F i f t h Annual R e p o r t . 1956 I n t e r i m R e p o r t , I n v e s t i g a t i o n s i n t o Measures f o r F l o o d C o n t r o l i n the E r a s e r R i v e r B a s i n . 1958 P r e l i m i n a r y Report on F l o o d C o n t r o l and H y d r o - e l e c t r i c Power i n the E r a s e r R i v e r B a s i n . F r e y , D a v i d G. ( e d i t o r ) 1963 L i m n o l o g y i n N o r t h A m e r i c a . The U n i v e r s i t y of W i s c o n s i n P r e s s , Madison. Gadd, K.G., L.C. Nixon and M.H, Webster 1962 The L i s i t u Tragedy. C e n t r a l A f r i c a n J o u r n a l of M e d i c i n e , V o l . 8, No. 12, pp. 491-508. G i l s o n , H.C, 1966 " d i s c u s s i o n " , See Lowe-McConnell, p. 48. Goldman, M a r s h a l l I , 1970 The Convergence of E n v i r o n m e n t a l D i s r u p t i o n , S c i e n c e , V o l . 1 7 0 , No, 3953, pp. 37-42, 1 32 Gough, D . I . and W.I, Gough 1969 L o a d T r i g g e r e d S e i s m i c A c t i v i t y a t L a k e K a r i b a . T r a n s a c t i o n s , A m e r i c a n G e o p h y s i c a l U n i o n , V o l . 50, p. 236. G r e a n y , W.H. 1952 S c h i s t o s o m i a s i s i n t h e G e z i r a I r r i g a t e d A r e a o f A n g l o - E g y p t i a n S u d a n . A n n a l s o f T r o p i c a l M e d i c i n e and P a r a s i t o l o g y , V o l . 4 6 , pp. 250-267 and 2 9 8 - 3 1 0 . H a l l , J .B. and W. P o p l e 1968 R e c e n t V e g e t a t i o n a l C h a nges i n t h e Lower V o l t a R i v e r . Ghana J o u r n a l o f S c i e n c e , V o l . 8, No, 1 and 2. H a r d i n g , D, 1966 L a k e K a r i b a , The H y d r o l o g y and D e v e l o p m e n t o f F i s h e r i e s , See L o w e - M c C o n n e l l , p p , 7-18, H a r d w i c k , W a l t e r G o r d o n 1958 The E f f e c t o f t h e P r o p o s e d Moran Dam on A g r i c u l t u r e W i t h i n t h e M i d d l e F r a s e r R e g i o n , B r i t i s h C o l u m b i a . U n p u b l i s h e d M a s t e r o f A r t s t h e s i s , The U n i v e r s i t y o f B r i t i s h C o l u m b i a . H a r e , F. K e n n e t h 1972 R a d i o i n t e r v i e w . S u n d ay M a g a z i n e , C a n a d i a n B r o a d c a s t -i n g C o r p o r a t i o n , 5 t h M a r c h , H e n k i n , Harmon 1969 S i d e E f f e c t s : R e p o r t on a C o n f e r e n c e on E c o l o g i c a l A s p e c t s o f I n t e r n a t i o n a l D e v e l o p m e n t . E n v i r o n m e n t , V o l . 1 1 , No. 1. H e r f i n d a h l , O r r i s C, and A l l e n V. K n e e s e 1965 Q u a l i t y o f t h e E n v i r o n m e n t , R e s o u r c e s f o r t h e F u t u r e I n c . , J o h n H o p k i n s P r e s s ( d i s t r i b u t o r ) . H i l l i n g , D. 1965 The V o l t a R i v e r P r o j e c t . The G e o g r a p h i c a l M a g a z i n e , V o l . 37, M a r c h , pp. 830-841 H i r a , P a r s o t a m R. 1969 T r a n s m i s s i o n o f S c h i s t o s o m i a s i s i n L a k e K a r i b a , Z a m b i a , N a t u r e , V o l , 224, pp. 6 7 0 - 6 7 2 . H o a r , W i l l i a m S. 1956 Power D e v e l o p m e n t and F i s h C o n s e r v a t i o n on t h e F r a s e r R i v e r , U n p u b l i s h e d r e p o r t , D e p a r t m e n t o f Z o o l o g y , The U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1 33 Houghton, G . V. 1966 M a i n t a i n i n g the S a f e t y and Q u a l i t y of Water S u p p l i e s . See Louie-iTicConnell, pp. 173-181. ^ I n t e r n a t i o n a l Commission on Large Dams 1970 T r a n s a c t i o n s , Dixieme congres i n t e r n a t i o n a l des grands b a r r a g e s . V o l . 3, 1-5 June, M o n t r e a l . J a c k s o n , P.B.N. 1966 The E s t a b l i s h m e n t of F i s h e r i e s i n Man-made Lakes ^ i n the T r o p i c s . See Lowe-McConnell, pp. 53-68. J a c k s o n , S i r R o b e r t 1964 The V o l t a R i v e r P r o j e c t , P r o g r e s s , V o l . 50, No. 282, pp. 146-161. James, L. Douglas and Robe r t E. Lee 1971 Economics of Water Resources P l a n n i n g . M c G r a u j - H i l l Book Company. J o r d a n , P. and Kae R a n d a l l 1962 B i l h a r z i a s i s i n T a n g a n y i k a : O b s e r v a t i o n s on i t s E f f e c t s and the E f f e c t s of Treatment i n S c h o o l -c h i l d r e n . J o u r n a l o f T r o p i c a l M e d i c i n e and Hy g i e n e , V o l . 65, No. 1, pp; 1-6, K a i l , R o l f and S. C h a r a l a m b a k i s 1970 Impounding of the Manicouagan 5 R e s e r v o i r s as Pos-s i b l e T r i g g e r Cause of L o c a l E a r t h q u a k e s . See I n t e r n a t i o n a l Commission on Large Dams, pp. 795-814, Kershaw, W.E. 1966 The Simulium Problem and F i s h e r y Development i n the Proposed N i g e r Lake, See Lowe-McConnell, pp, 95-98. L a g l e r , K a r l F. 1969 ( e d i t o r ) Man-made L a k e s , P l a n n i n g and Development. U n i t e d N a t i o n s , Food and A g r i c u l t u r a l O r g a n i z a t i o n , Rome, 1971 E c o l o g i c a l E f f e c t s of H y d r o e l e c t r i c Dams. See B e r k o w i t z and S q u i r e s , pp. 133-157, Land, Thomas 1968 The Zambezi Y i e l d s I t s R i c h e s . Contemporary Review, V o l . 213, No. 1232, pp. 132-135. L a n e, R . G . T . 1970 Major Problems i n the O p e r a t i o n and Maintenance of Dams and R e s e r v o i r s . See I n t e r n a t i o n a l Commission on Large Dams, pp, 329-348. 1 34 L a r k i n , P.A. 1956 Power Development and F i s h C o n s e r v a t i o n on the F r a s e r R i v e r . U n p u b l i s h e d r e p o r t , I n s t i t u t e of F i s h e r i e s , The U n i v e r s i t y of B r i t i s h C olumbia. L a u f f , George H, ( e d i t o r ) 1967 E s t u a r i e s . American A s s o c i a t i o n f o r the Advancement of S c i e n c e . Lawson, George UJ. 1970 Lessons of the V o l t a — A new Man-made Lake i n T r o p i c a l A f r i c a . B i o l o g i c a l C o n s e r v a t i o n , V o l . 2, No. 2. 1967 "Sudd" F o r m a t i o n on the V o l t a Lake. B u l l e t i n de l ' l . F . A . N . , T. XXIX, s e r . A, No. 1. L e e n t v a a r , P. 1966 The 3rokopondo R e s e a r c h P r o j e c t , Surinam, See Lowe-McConnell, pp. 33-41. L e o p o l d , Luna 8, Frank E. C l a r k e , Bruce B. Hanshaw and 1971 James R. B a l s l e y A Pr o c e d u r e f o r E v a l u a t i n g E n v i r o n m e n t a l Impact. U n i t e d S t a t e s , Department of the I n t e r i o r , Geolog-i c a l S u rvey, C i r c u l a r 645. L e w i s , D.J. 1966 N i l e C o n t r o l and i t s E f f e c t s on I n s e c t s of M e d i c a l Importance. See Lowe-McConnell, pp. 43-46, L i e c h t i , Ul. and UJ. H a e b e r l i 1970 Les s e d i m e n t a t i o n s dans l e b a s s i n de compensation de P a l a g n e d r a e t l e s d i s p o s i t i o n s p r i s e s pour l e de b l a i e m e n t des a l l u v i o n s . See I n t e r n a t i o n a l Commission on Large Dams, pp. 19-38. L i t t l e , E.C.S. 1966 I n v a s i o n of Man-made Lakes by P l a n t s . See Lowe-McConnell, pp. 75-84. L i t t l e , Tom 1965 High Dam a t Aswan. The John Day Company, New York, Lowe-McConnell, R.H. ( e d i t o r ) 1966 Man-made L a k e s . Symposia of the I n s t i t u t e of B i o l o g y , Number 15, 30 September and 1 O c t o b e r , 1965, Academic P r e s s , London. Mermel, T.W. 1970 World's H i o h e s t and L a r g e s t Dams. C i v i l E n g i n e e r i n g , V o l . 40, No. 7, pp. 73-76. 1 35 Moxon, James.. 1959 V o l t a : Man's G r e a t e s t Lake. Andre Deutsch L i m i t e d , L ondon. Neel , Joe K e n d a l l 1963 Impact of R e s e r v o i r s . See F r e y , pp. 575-594. Obeng, L e t i t i a E. ( e d i t o r ) 1969 Man-made L a k e s : The A c c r a Symposium. Ghana C o u n c i l f o r S c i e n t i f i c and I n d u s t r i a l R e s e a r c h , 21 t o 26 November, 1966, Ghana U n i v e r s i t i e s P r e s s . P a v l o v s k i i , E.N, ( e d i t o r ) 1957 T r a n s a c t i o n s of the 6th Conference on the B i o l o g y of Waters, Academy of S c i e n c e s of the U.S.S.R,, T r a n s l a t e d by M. Raveh and 8. G o l e k , I.P.S.T. P r e s s , J e r u s a l e m , P o p l e , W. and M. Rogoyska 1969 The E f f e c t of the V o l t a R i v e r H y d r o e l e c t r i c P r o j e c t on the S a l i n i t y of the Lower V o l t a R i v e r . Ghana J o u r n a l of S c i e n c e , V o l . 9, No. 1. P o t t e r , R.E. 1957 Moran D a m — F i s h and Power. The B.C. P r o f e s s i o n a l E n g i n e e r , V o l . 8, No. 3, P r e t i o u s , E.S. 1972 Downstream S e d i m e n t a t i o n E f f e c t s of Dams on the F r a s e r R i v e r , B.C. Department of C i v i l E n g i n e e r i n g , Water Resources S e r i e s Number 6, The U n i v e r s i t y of B r i t i s h Columbia. P t e r , T. 1967 F i s h P o p u l a t i o n Changes i n the V o l t a Lake i n Ghana D u r i n g i t s F i r s t S i x t e e n Months, H y d r o b i o l o g i a , V o l . 30, pp. 193-220. P y e f i n c h , K.A. 1966 H y d r o - e l e c t r i c Schemes i n S c o t l a n d , B i o l o g i c a l Problems and E f f e c t s on Salmonid F i s h e r i e s . See Lowe-McConnell, pp. 139-145. Reeve, W.H, 1960 P r o g r e s s and the Geographic S i g n i f i c a n c e of the K a r i b a Dam, Geographic J o u r n a l , V o l , 126, pp, 140-146. Rothe, J.P. 1968 F i l l a Lake, S t a r t an E a r t h q u a k e . New S c i e n t i s t , V o l . 19, No. 605, pp. 75-78. 1 36 R u b i n , N e v i l l e and W i l l i a m M. Warren ( e d i t o r s ) 1968 Dams i n A f r i c a . Augustus M, K e l l e y P u b l i s h e r s , New York. R z o s k a , J u l i a n 1966 The B i o l o g y of R e s e r v o i r s i n the U.S.S.R. See Lowe-McConnell, pp. 149-153. S c h u l t z , W. M, , e t a l . 1970 Death of a D e l t a - - A B r i e f t o Government. Water Resources C e n t r e , The U n i v e r s i t y of A l b e r t a , 5 June. Scudder, Thayer 1965 The K a r i b a Case: Man-made Lakes and Resource Development i n A f r i c a . B u l l e t i n of the Atomic S c i e n t i s t s , V o l . 21, December, pp. 6-11. 1966 Man-made Lakes and P o p u l a t i o n R e s e t t l e m e n t i n » A f r i c a . See Lowe-McConnell, pp, 99-107. 1969 The E c o l o g i c a l Hazards of Making a Lake, See F a r v a r . S h i f f , C.J. 1969 Host and P a r a s i t e i n R h o d e s i a . See F a r v a r . Shrum, G.M. 1971 M e e t i n g B r i t i s h Columbia's Energy R e q u i r e m e n t s . P u b l i c a d d r e s s i n the H.R. M a c M i l l a n L e c t u r e S e r i e s , 14 O c t o b e r , Vancouver. S i m a i k a , Y.M. 1970 D e g r a d a t i o n of the N i l e Bed Due t o the I n t e r c e p t i o n of S i l t i n the High Aswan R e s e r v o i r . See I n t e r n a t -i o n a l Commission of Large Dams, pp, 1161-1182, S m i t h , Norman-1971 A H i s t o r y of Dams. P e t e r D a v i e s , London. S o r e n s e n , Jens C. 1971 A Framework f o r I d e n t i f i c a t i o n and C o n t r o l of Resource D e g r a d a t i o n and C o n f l i c t i n the M u l t i p l e Use of the C o a s t a l Zone, Department of Landscape A r c h i t e c t u r e , U n i v e r s i t y of C a l i f o r n i a , B e r k l e y . S t e r l i n g , C l a i r e 1971 Aswan Dam Loses a F l o o d of Problems. L i f e , V o l . 70, No, 5, pp. 46-47. S t r o b e l , G e r a l d A, 1970 Oxygen Sources f o r A q u a t i c Ecosystems, From P r o c e -e d i n g s of the 1970 Annual T e c h n i c a l M e e t i n g of the I n s t i t u t e f o r E n v i r o n m e n t a l S c i e n c e s , Mt, P r o s p e c t , I l l i n o i s . 1 37 S t r o u d , R i c h a r d H. 1966 Comments on t h e Symposium i n t h e L i g h t o f t h e B i o l o g y o f U.S. R e s e r v o i r s . See Lowe M c C o n n e l l , pp. 2 0 5 - 2 0 8 . The Sun Moran P l a n S c r a p p e d . 23 M a r c h , 1 9 7 2 , p. 1. No Dam i n my T i m e - - 8 e n n e t t . 28 M a r c h , 1 9 7 2 , p. 1. S u t t o n , Imere 1970 Dams and t h e E n v i r o n m e n t . G e o g r a p h i c a l R e c o r d , V o l . 6 0 , pp. 1 2 8 - 1 2 9 . U n i t e d S t a t e s , D e p a r t m e n t o f t h e I n t e r i o r , B u r e a u o f 1964 R e c l a m a t i o n The S t o r y o f t h e C o l u m b i a B a s i n P r o j e c t . U.S. Go v e r n m e n t P r i n t i n g O f f i c e . U n i t e d S t a t e s 1970 N a t i o n a l E n v i r o n m e n t a l P o l i c y A c t o f 1969. V a a s , K.F. 1966 L a k e s i n D u t c h R e c l a m a t i o n Schemes. See L o w e - M c C o n n e l l , pp. 1 1 9 - 1 2 6 . van d e r S c h a l i e , H e n r y 1969 S c h i s t o s o m i a s i s : The D i s e a s e o f S l o w e d Down W a t e r s . See E a r v a r , Waddy, B . B . 1966 M e d i c a l P r o b l e m s A r i s i n g f r o m t h e M a k i n g o f L a k e s i n t h e T r o p i c s . See L o w e - M c C o n n e l l , pp. 87-94. Warmann, J . Sg. G. 1969 O n c h o c e r c i a s i s and t h e V o l t a Dam C o n s t r u c t i o n . See Obeng, pp. 3 5 2 - 3 6 0 . W o r t h i n g t o n , E.8. 1966 I n t r o d u c t o r y S u r v e y : Man-made L a k e s . See L o w e - M c C o n n e l l , pp. 3-5, Z h i v a g o , A,V. and K.O. Lan g e 1957 M a j o r P a t t e r n s o f D e v e l o p m e n t o f t h e S h o r e Zones o f L a r g e R e s e r v o i r s . See P a v l o v s k i i . * •* # I M P A C T I D E N T I F I C A T I O N F R A M E W O R K F i g u r e 4. t o accompany: OBJECTIVES 1. F l o o d hazard r e d u c t i o n 2. H y d r o e l e c t r i c g e n e r a t i o n 3. I r r i g a t i o n s u p p l y 4. Navigation 5. R e c r e a t i o n AN IMPACT IDENTIFICATION FRAMEWORK FOR LARGE RESERVOIRS by s P e t e r T. M i d g l e y 1972 INSTRUCTIONS NOTE o A I n d i c a t e s t h a t the "method of e x e c u t i o n " i n d i c a t e d i s e s s e n t i a l f o r achievement of the p a r t i c u l a r " o b j e c t i v e " . I n d i c a t e s a p o t e n t i a l "impact" stemming from the "method of e x e c u t i o n " i n d i c a t e d at the column head, * "Impact" t o " m u l t i p l e order consequences" to " f i n a l consequence' i n d i c a t e s the p o t e n t i a l l i n k a g e of e f f e c t s . 1 . 2. 3. Shade c i r c l e s t o i n d i c a t e the "methods of e x e c u t i o n " which are r e q u i r e d t o meet the s t a t e d " o b j e c t i v e s " of a p a r t i c u l a r p r o j e c t . Shade t r i a n g l e s t o i n d i c a t e the p o t e n t i a l " i m p a c t s " which stem from the r e q u i r e d "methods of e x e c u t i o n " . Shade or check p a r e n t h e s e s to i n d i c a t e p r o b a b l e e f f e c t l i n k a g e s between " m u l t i p l e o r d e r consequences" and " f i n a l consequence". N o t e i Shading of the second and t h i r d s t e p s may be c o l o u r coded to i n d i c a t e the c e r t a i n t y of the o c c u r r e n c e or non o c c u r r e n c e of p o t e n t i a l e f f e c t s . F u r t h e r shading may i n d i c a t e the i m p o r t -ance of these e f f e c t s on an e v a l u a t i v e s c a l e . For example i J\ (_) H i g h l y p r o b a b l e A (_) U n c e r t a i n A (_) H i g h l y improbable A (_) High importance A (_) moderate importance A (_) Low importance A (_) U n c e r t a i n importance Ref. No. IMPACT MULTIPLE ORDER CONSEQUENCES FINAL CONSEQUENCE z • ^ 3 ° U CD y I h LLJ o a 4 A A-A A-4r AA A --A-(1) I n f l u x of c o n s t r u c t i o n workers (_) Unplanned r e s i d e n t i a l development 8 Crowding "* Townsite c o n s t r u c t i o n (_) Crowding S e r v i c i n g problems Landscape d e g r a d a t i o n P u b l i c h e a l t h problems P u b l i c h e a l t h problems A-o § *» U 3 U *> (I § CJ 3 a u o o § *> a 3 U a CM tO o> m c c M o - H «t <-> -A * J —1 u —t m 3 b~ X) T3 Et a U • H E >-) O < C B > 0 o f-l m B 1-1 fe-e> -j 6 . SI « O e u Z SI a c a t-* I-I o M m t - •H *» «-t n *» ac fl c •** UJ ffi a c a. M o »*-* o U o • « to c o « N « • o (2) I n f l u x of unemployed and u n s k i l l e d (_) Unemployment (_) Unplanned r e s i d e n t i a l development (~) Crowding (_) S u b s i s t e n c e l i v i n g Government w e l f a r e support O v e r c r o p p i n g of s o i l D e p l e t i o n of game r e s e r v e s See Reference No. 1 See Reference No. 1 (3) Improved a c c e s s t o dam and r e s s r v o i r a r e a (_) Long term p o p u l a t i o n growth { ) Unplanned r e s i d e n t i a l development ["_) Crowding ~) Unemployment [~) Unplenned l a n d use (_) I n c r e a s e d s h o r t term and "** r e c r e a t i o n a l use [_) See Reference No. 1 ~ See Reference No, 1 See R e f e r s n c e No. 2 ' ) S e r v i c i n g problems >Z) O v e r c r o p p i n g of s o i l "* E r o s i o n ) Inadequate f a c i l i t i e s ) D e p l e t i o n of game r e s e r v e s ~) Damage t o n a t u r a l environment ( 4 ) R e l o c a t i o n (_) Crowding (_) F o r a g i n g n a t i v e f l o r a (_) Inadequate s a n i t a t i o n See Reference No. 1 O v e r c r o p p i n g of s o i l D e p l e t i o n of game r e s e r v e s P o i s o n i n g and i l l n e s s D i s e a s e (5.) Readjustment s t r e s s e s (_) P u b l i c h e a l t h problems (£) Reduced downstream d i s c h a r g e (_) See "Downstream Flow R e d u c t i o n " ~* (Column 5) (J ) S t r a n d i n g of a n i m a l s (_) Drowning of a n i m a l s (fl) E u t r o p h i c a t i o n (9) A b s o r p t i on (10) Seepage _) High b i o l o g i c a l p r o d u c t i v i t y (_) D e p l e t i o n of d i s s o l v e d axygen ( ) Release of oxygen d e v o i d waters .) Anaerobic c h e m i c a l c o n d i t i o n s ( e g , H~S) (_) R e lease of f o u l e d waters J Increased f i s h p o p u l a t i o n s ( ) O v e r f i s h i n g Reduced u i o . a c t i v i t y i n l a k e Reduced b i o . a c t i v i t y downstream Reduced b i o . a c t i v i t y i n l a k e Reduced b i o . a c t i v i t y downstream I n c r e a s e i n u n d e s i r a b l e s p e c i e s F a i l u r e of l a k e f i s h e r y _) Slowing of i n i t i a l r e s . f i l l i n g (_) F a i l u r e t o meat t a r g e t o p e r a t i o n ™ date .) T r a n s p o r t of water beyond watershed .) A q u i f e r c h a r g i n g (_) T r a n s p o r t of water beyond watershed (_) Loss of r e s e r v o i r water (_) R a i s i n g of water t a b l e (_) C r e a t i o n of new l a k e s , marshes ( J (_) Supplementation of i r r i g a t i o n water (_) S a l t i n g of u s a b l e l a n d I n c r e a s e i n e f f e c t i v e f l o o d hazard r e d u c t i o n Supplemental water s u p p l y Feedback on h y d r o e l e c . c a p a c i t y Feedback on i r r i g a t i o n c a p a c i t y Feedback on r e c r e a t i o n p o t e n t i a l Feedback on n a v i g a t i o n p o t e n t i a l [ ) I n c r e a s e d r e c r e a t i o n p o t e n t i a l ) Loss of l a n d [ ) I n c r e a s e d a g r i c u l t u r a l output ) Rdddced a g r i c u l t u r a l output ( 1 1 ) R e d u c t i o n or e l i m i n a t i o n of c r i t i c a l h a b i t a t s (_) R e d u c t i o n or e l i m i n a t i o n of p l a n t or animal s p e c i e s ( 1 2 ) P h y s i c a l mass of s t o r e d water 1:1 Weight on e a r t h ' s c r u s t Mater l u b r i c a t i o n of f a u l t s 1:1 S e i s m i c a c t i v i t y and earthquakes S e i s m i c a c t i v i t y and earthquakes H P r o p e r t y damage and deaths P r o p e r t y damage and deaths (11) S e d i m e n t a t i o n of r e s e r v o i r (_) Reduced r e s e r v o i r s t o r a g e c a p a c i t y ( ) Redu c t i o n of b a s i n p e r m e a b i l i t y (Z) S l u i c i n g of sediments (~) S e a l i n g of s l u i c i n g o u t l e t s (_) Dredging and g r a v e l e x t r a c t i o n (_) Reduced downstream s i l t l o a d (_) Choking of downstream b i o t a (~) Complete draw-down Feedback on f l o o d s t o r a g e c a p a c i t y Feedback on h y d r o e l e c t r i c c a p a c i t y Feedback on i r r i g a t i o n c a p a c i t y Reduction of seepage l o s s e s Reduced b i o . a c t i v i t y downstream Short term l o s s of r e s e r v o i r use See "Draw-down" (Column 7) U n a n t i c i p a t e d c o s t s G r a v e l s u p p l y See Reference No. 14 (14) Reduced downstream s i l t l o a d m i o o * if) KQ S o a 19 U a E T) o o c u a OBJECTIVES 1. F l o o d hazard r e d u c t i o n 2. H y d r o e l e c t r i c g e n e r a t i o n Q—0—0-3. I r r i g a t i o n s u p p l y 4. N a v i g a t i o n 5. R e c r e a t i o n Reduced s i l t d e p o s i t i o n I n c r e a s e d r i v e r bank e r o s i o n P r e v e n t i o n of f l o o d s i l t d e p o s i t s I n c r e a s e d s u n l i g h t p e n e t r a t i o n Reduction o f e s t u a r i n e n u t r i e n t s ) Reduced d r e d g i n g requirement ~) U n d e r c u t t i n g r i v e r bank f a c i l i t i e s _) Decrease i n s o i l f e r t i l i t y Improved n a v i g a t i o n Bank s t a b i l i z a t i o n requirement Reduced a g r i c u l t u r a l output I n c r e a s e d downstream b i o , a c t i v i t y Decreased o f f - s h o r e b i o . a c t i v i t y (15) D i s s o l u t i o n of b a s i n m a t e r i a l s (_) Water q u a l i t y change (_) Release of f o u l e d waters (_) U n s u i t a b i l i t y of water f o r ~ domestic and i n d u s t r i a l uses H Changes i n r e s e r v o i r ( b i o t a Changes i n downstream b i o t a (16) E v a p o r a t i o n (_) Loss of s t o r e d water (_) C l i m a t i c changes (_) I n c r e a s e i n e f f e c t i v e f l o o d hazard r e d u c t i o n Feedback on h y d r o e l e c . c a p a c i t y Feedback on i r r i g a t i o n c a p a c i t y Feedback on n a v i g a t i o n p o t e n t i a l Feedback on r e c r e a t i o n p o t e n t i a l (_) See Reference No. 17 (17) C l i m a t i c changes |_| Increased p r e c i p i t a t i o n Improved d i s e a s e v e c t o r h a b i t a t ) Long term change i n b i o t a ) Improved a g r i c u l t u r a l output ~) D i s e a s e (man and a n i m a l ) ( 1 8 ) T h e r m a l s t r a t i f i c a t i o n (_) Hypolimnion oxygen d e p l e t i o n ! (_) A n a e r o b i (_) Overturn of r e s e r v o i r water (_) A n a e r o b i c c h e m i c a l c o n d i t i o n s ( e g . H^S) ™ " 1 Release of f o u l e d waters _) F o u l i n g of s u r f a c e waters ~) R e s t o r a t i o n of h y p o l i m n i o n oxygen (_) Reduced b i o . a c t i v i t y below — t h e r m o c l l n e (_) Reduced b i o . a c t i v i t y downstream (_) Reduced b i o . a c t i v i t y i n l a k e (_) R e s t o r a t i o n of deep water — b i o . a c t i v i t y ( i q \ Delay i n s p r i n g water temperature x — ' r i s e — — — — (_) Delay i n i c e break-up {_) Changes i n downstream b i o t a {_) L e n g t h e n i n g of w i n t e r [_) Delay of r i v e r n a v i g a t i o n (20) Delay of f a l l water temperature d e c l i n e i-i Delay i n i c e f o r m a t i o n P r e v e n t i o n of i c e f o r m a t i o n (_) P r e v e n t i o n of i c e s c o u r i (_) Changes i n downstream b i o t a (_) E x t e n s i o n of r i v e r n a v i g a t i o n (_) Growth of r i v e r weeds (21 ) S t a g n a t i o n of water 8 Oxygen d e p l e t i o n Growth of water weeds (_) Reduced b i o l o g i c a l a c t i v i t y (_) See Reference NO. 22 (22)Growth of water weeds _) Decrease i n r e s e r v o i r s t o r a g e volume _) O b s t a c l e on water s u f r a c e _) B l o c k i n g of s p i l l w a y s and i n t a k e s _) S c a l i n g of lower waters (_) Oxygen d e p l e t i o n _) Increased e v a p o r a t i o n __) P r o v i s i o n of h a b i t a t f o r micro-organisms ) S t a b i l i z a t i o n of water ( ) Promotion of d i s e a s e v e c t o r s (_) Feedback on f l o o d s t o r a g e c a p a c i t y Feedback on h y d r o e l e c t r i c c a p a c i t y Feedback on i r r i g a t i o n c a p a c i t y Feedback on n a v i g a t i o n p o t e n t i a l Feedback on r e c r e a t i o n p o t e n t i a l Feedback on h y d r o e l e c . g e n e r a t i o n Feedback on i r r i g a t i o n s u p p l y Reduced b i o . a c t i v i t y i n l a k e F i s h l o s s e s I n c r e a s e i n e f f e c t i v e f l o o d hazard r e d u c t i o n Feedback on h y d r o e l e c t r i c c a p a c i t y Feedback on i r r i g a t i o n c a p a c i t y P r o v i s i o n of n u t r i e n t s f o r h i g h e r forms such as f i s h (_.) See Reference No. 26 (23) Landward l i t t o r a l f o r m a t i o n i : l Beach f o r m a t i o n E r o s i o n of shore f a c i l i t i e s 8 Improved r e c r e a t i o n p o t e n t i a l F o undation s t a b i l i z a t i o n r e q u i r e d ( 2 4 ) L i n e a l l i t t o r a l f o r m a t i o n ) Beech f o r m a t i o n ( ) E r o s i o n of p r o m o n t o r i e s _) F i l l i n g of bays '_) E r o s i o n of shore f a c i l i t i e s Improved r e c r e a t i o n p o t e n t i a l ' Loss of breakwater e f f e c t on shore Loss of s h e l t e r e d water Foundation s t a b i l i z a t i o n r e q u i r e d (25) Change of groundwater t a b l e (_) Formation of s h o r e l i n e swamps (_) Promotion of d i s e a s e v e c t o r s (_) S h o r e l i n e v e g e t a t i o n changes (_) See Reference No. 26 ( 26 ) S t a b i l i z a t i o n of impounded water Changes i n i n c i d e n c e of d i s e a s e v e c t o r s i (_) Breeding of s n a i l s (_) I n c r e a s e d i n c i d e n c e of b i l h a r z i a ( ) Breeding of mosquitoes (__) I n c r e a s e d i n c i d e n c e of m a l a r i a ( ) Breeding of t s e t s e f l y (_) I n c r e a s e d i n c ' . of t r y p a n o s o m i a s i s (_) Reduction i n b r e e d i n g of b l a c k f l y (_) Reduced I n c ' . of o n c h o c e r c i a s i s (_) Human deaths and s u f f e r i n g (~) Human deaths and s u f f e r i n g , l i v e s t o c k and game l o s s e s (_) Human deaths and s u f f e r i n g l i v e s t o c k and game l o s s e s (_) Improved p u b l i c h e a l t h (27) I n u n d a t i o n of s c e n i c and h i s t o r i c s i t e s (_) I r r e t r i e v a b l e c u l t u r a l l o s s (28) Decreased c r o s s r i v e r access (29) Lowered s i l t b e a r i n g c a p a c i t y (_) Break down of s o c i a l c o n t a c t p a t t e r n s (_) D e p o s i t i o n at downstream t r i b -u t a r y c o n f l u e n c e s (_) Choking of downstream b i o t a (_) S i l t i n g of bank f a c i l i t i e s (_) Reduced b i o . a c t i v i t y downstream (30) I n c r e a s e d e s t u a r i n e s a l i n i t y (_) B i o l o g i c a l h a b i t a t changes ! : i Break down of food c h a i n Decrease i n e s t u a r i n e n u t r i e n t product i o n (_) E s t u a r i n e s p e c i e s changes (_) Reduced b i o . a c t i v i t y o f f - s h o r e (31 ) Lowering of e s t u a r i n e or d e l t a c h a n n e l s , marshes, l a k e s , e t c . (_) V e g e t a t i o n changes (_) Ice f o r m a t i o n t o bottom (_) Exposure of spawning beds (_) Expansion of I n s e c t b r e e d i n g a r e a (_) Loss of food f o r h e r b i v o r s (_) E l i m i n a t i o n of b i o l o g i c a l h a b i t a t (_) F i s h l o s s e s (32)Reduced e s t u a r i n e s t r a t i f i c a t i o n (_) I n c r e a s e d bottom oxygen l e v e l ( 3 3 ) L o w e r i n g of r i v e r bank water t a b l e (_) V e g e t a t i o n changes (_) D r y i n g of a g r i c u l t u r a l 1 and (34) C r e a t i o n of wide swampy beach (_) Exposure of spawning beds (_) K i l l i n g of a q u a t i c weeds (_) Break down of p r e d a t o r - p r e y f i s h r e l a t i o n s h i p s (_) S t r a n d i n g of n a v i g a t i o n a l f a c i l i t i e s (_) Breeding of i n s e c t s ( 3 5 ) B l o c k i n g of anadromous f i s h (_) B u i l d i n g of f i s h l a d d e r s (_) Some f i s h miss l a d d e r e n t r a n c e s (36) Emergence of anadromous f i s h from f i s h l a d d e r i n t o r e s e r v o i r B Current sweeps f i s h over dam Confusion and d e l a y i n r e s e r v o i r (37) Passage of f r y over s p i l l w a y or through t u r b i n e s (_) S u b s t a n t i a l f i s h l o s s e s (3JL) C o n f u s i o n of downstream m i g r a n t s (_) Delay of m i g r a t i o n (_) F a i l u r e t o migrate downstream (3g) R e d u c t i o n of spawning bed area (_) Crowding ( 4 0 ) I n c r e a s e d downstream temperature (_) M e t a b o l i c changes f o r f i s h ( ) Death (~) R e d u c t i o n of s u c c e s s f u l spawning ( 4 1 ) D o w n s t r e a m oxygen l e v e l r e d u c t i o n (_) S u f f o c a t i o n of downstream spawning beds (42.) Changes i n s i l t a t i o n p a t t e r n s (_) Suf f o c a t i o n of f i s h eggs (_) E l i m i n a t i o n or r e d u c t i o n of animal p o p u l a t i o n s (_) E l i m i n a t i o n or r e d u c t i o n of f i s h and a n i m a l p o p u l a t i o n s H D e c l i n e of commercial f i s h e r y _ I n s e c t i n c r e a s e s , See Reference No. 34 (_) I n s e c t i n c r e a s e s , See Reference E1CU_3J (_) I n c r e a s e d e s t u a r i n e b i o . a c t i v i t y Animal p o p u l a t i o n changes Loss of g r a z i n g l a n d I r r i g a t i o n requirement Reduced a g r i c u l t u r a l output 8 8 Feedback on r e c r e a t i o n p o t e n t i a l R e d u c t i o n or e l i m i n a t i o n of f i s h p o p u l a t i o n s (_) R e d u c t i o n or e l i m i n a t i o n of — f i s h p o p u l a t i o n s Improved beach a e s t h e t i c s E l i m i n a t i o n of micro-organism h a b i t a t Feedback on n a v i g a t i o n p o t e n t i a l Human nuis a n c e and d i s e a s e Loss of l i v e s t o c k and w i l d l i f e ( ) E l i m i n a t i o n of f i s h p o p u l a t i o n (~) R e d u c t i o n of f i s h p o p u l a t i o n H Death of o l d f i s h b e f o r e spawning _ Reduction of s u c c e s s f u l spawning (_) R e d u c t i o n of f i s h p o p u l a t i o n (_) m o d i f i c a t i o n of f i s h l i f e c y c l e (_) R e d u c t i o n of f i s h p o p u l a t i o n (__) R e d u c t i o n of f i s h p o p u l a t i o n 8 E l i m i n a t i o n of f i s h p o p u l a t i o n R e d u c t i o n of f i s h p o p u l a t i o n (_) R e d u c t i o n of f i s h p o p u l a t i o n ( ) Redu c t i o n of f i s h p o p u l a t i o n FIGURE 4-I M P A C T I D E N T I F I C A T I O N F R A M E W O R K F i g u r e 6. to accompany: AN IMPACT IDENTIFICATION FRAMEWORK FOR LARGE RESERVOIRS O B J E C T I V E S 1. F l o o d h a z a r d r e d u c t i o n . M y d r o a l a c t r l c g e n e r a t i o n . I r r i g a t i o n s u p p l y . N a v i g a t i o n . R a c r a a t i o n -CD UJ • X by: P e t e r T. Midg l e y 1972 I N S T R U C T I O N S ^ n a d t c i r c l e s t o i n d i c a t e the "methods o f e x e c u t i o n " w h i c h a r e r e q u i r e d t o meet t h e s t a t e d " o b j e c t i v e s " o f a p a r t i c u l a r or o j a c t . NOT F Shade t r i a n g l e s t o i n d i c a t e t h e p o t e n t i a l f r o m t h e r e q u i r e d "methods o f e x e c u t i o n " . i m p a c t s " w h i c h stem w CJ • V-«* a 0 k-in n oc u a %_ o < —J o > m * c o • o o • <—> c • < •— *) o ft f u O T. 3 ** —» UJ a. tr up e | < D a h *J cr -J C W UJ tr o —i C a a a o r- oi m * «"> •£> r«- Q •j (1) I n f l u x o f c o n t t r j c t l o n w o r k e r s I n d l c e t e s t * e t t> e me-ho- c ' exe u t j »• i r icit«. i s e t s a n t l a l ' o r a c h i e v e m e n t o f -ha par • It J 1» r "dj at 1 a" I n d i c a t e s a p o t e n t i a l " i i i p i c " ^t^^m nc f i m e x e c u t i o n " i n d ; c e * e d a t K s Oi isv h e " I m o e e t " t o " m u l t i p l e c d » r o seauei s e s " a i n d i c a t e * a o t e n ' i s l 1 nksg» o' e f f e c t * 3. Shade or c h e c k p a r e n t h e s e s t o i n d i c a t e p r o b a b l e e f f e c t l i n k a g e s b e tween " n u l t l p l e o r d e r c o n s e q u e n c e s " and " f i n a l c o n s e q u e n c e " . Note S h a d i n g o f t h e s e c o n d and t h i r d s t e p s may be c o l o u r c o d e d t o I n d i c a t e t h e c e r t a i n t y o f t h e o c c u r r e n c e o r non o c c u r r e n c e o f p o t e n t i a l e f f e c t s . F u r t h e r s h a d i n g may I n d i c a t e t h e i m p o r t -a n c e o f t h e s e e f f e c t s on an e v a l u a t i v e s c a l e . F o r e x a m p l e s ( ) h i g h l y p r o b a b l e ( ) U n c e r t a i n (_) H i g h l y i m p r o b a b l e A (_) H i g h i m p o r t a n c e A (_) m o d e r a t e i m p o r t a n c e A (_) Low i m p o r t a n c e A (_) U n c e r t a i n i m p o r t a n c e I M P A C T ( 2 ) I n f i u a o f un e m p l o y e d end n s w l l i e d bnamplovma- t M U L T I P L E O R D E R C O N S E Q U E N C E S Lipalanne 1"' r e s i d e r - t l s l l e v e l o o m e n t 4J) c r o w d i r , v_ ' o e m s i t a c o n s t r JC * l on . r o w d i n g F I N A L C O N S E Q U E N C E Subs i s t a n c e 1 i v i n g {^) n p l a ~ n e d r e s i d e n t i a l - e v e l o p m e . t 9 r -Aid g (2) I m p r o v e d a c c e a s t o dam and r e s e r v o i r a r e a (m LohQ ter» o o a u l a t i o n g r o w t h ( ) J n p l a n n e d r e s i d e n t i a l d e v e l o p m e n t H ( i ) R a l o c a t i o n eft C r o w d i n g (_) Unemployment ( _) U n p l a n n e d l a n o u sc ^ I n c r e a a a d s h o r t t e r m and r e c r e e t i o n a l use _) S e r v i c i n g p r o b l e m s L a n d s c a p e d e g r a d a t i o n P u b l i c h e a l t h p r o b l e m s P u b l i c h e a l t h p r o b l e m s fmm) Government w e l f a r e s u p p o r t (f,P O v e r c r o p p i n g o f s o i l ftm j e p l e t i o n o f game r e s e r v e s . ) See R e f e r e n c e No. 1 lf_P See R e f e r e n c e No. 1 Croa>di ng I o r a g i n g n a t i v e f l o r a • n a d e q u a t e s a n i t a t i o n (5) r e a d j u s t m e n t s t r e s s e s j (&) R e d u c e d d o w n s t r e a m d i s c h a r g e ( 7 j S t r a n d i n g o f a n i m a l s 1 (£) i - u t r o p h i c a t i o n H (9.) A b s o r p t i o r A I 1_0) s e e p a g e " e d u c t i o n o r a l i e i i n a t i o n o f c r i t i c a l h a n i t a t s (. 1_2) P h y * i c a l mass o f s t o r e d w e t e r 4_) H i g h b i o l o g i c a l p r o n u c ' i v l ' . y (_' J e p i e t i o r o f d i s s o l v e d e»/gen ('_) R e l e a s e of oxygen d e v o i d w a t e r s (_) A n a e r o b i c '"nemlcal c o n d i t i o n s ( e g . H 2 S ) (_) -<eiea»e of f o u l e d «aters (00 I n c r e a s e d f i s h p n p t i a ' i o n s |Bj>) O v e r f i s h i n g (_) See R e f e r e n c e No. 1 (~) See R e f e r e n c e No. 1 (_) s a t R e f e r e n c e No. 2 i ) S e r v i c i n g p r p b l e m s O v e r c r o p p i n g o f s o i l (^) L r o s i o n ( ) I n a d e q u a t e f a c i l i t i e s (_) D e p l e t i o n o f game r e s e r v e s (_) Damage t o n a t u r a l e n v i r o n m e n t 0T) See R e f e r e n c e No. 1 O v e r c r o p p i n g o f s o i l i t i o n o f game r e s e r v e s (£) P o i s o n i n g and i l l n e s s (_) P u b l i c h e a l t h p r o b l e m s (_) See "Downatream F l o w R e d u c t i o n ' ( C o l u m n 5) D r o w n i n g o f a n i m a l s (_) R e d u c e d j i o . a c t i v i t y i n l a k e (_) R e d u c e d b i o . a c t i v i t y d o w n s t r e a m i d u c e d b i o . a c t i v i t y i n l a k e i d u c e d b i o . a c t i v i t y d o w n s t r e a m n c r e a s e i n u n d e s i r a b l e s p e c i e s i l l u r e o f l a k e f i s h e r y _) S l o w i n g o f i n i t i a l r e s . f i l l i n g (•__) T r a n s p o r t o f w a t e r b e y o n d meter shed (_) A q u i f e r c h a r g i n g ( T r a n s p o r t of w a t e r oeyond w a t e r s h e d L o s s o f r e s e r v o i r w e t e r (_) R e i s i g of w a t e r t a b l a _ Ci *e l o r o' n*w L a k e s , m a r s h a l • (_) F a i l u r e t o meet t a r g e t o p e r a t i o n d a t e (e£< I n c r e a s e In a f f e c t i v e f l o o d h a z a r d r e d u c t i o n S u p p l e m e n t a l w a t e r s u p p l y 4*} F e e d b a c k on h y d r o e l e c . c a p a c i t y (iflk Feedback on i r r i g a t i o n c a p a c i t y F e e d b a c k pn r e c r e a t i o n p o t e n t i a l \Wf} F e e d b a c k on n a v i g a t i o n p o t e n t i a l (_) I n c r e a s e d r e c r e a t i o n p o t e n t i a l L o s s o f l a n d p S u p p l e m e n t e t i o r o f i r r i g a t i o n w a t e r j ^ I n c r e a s e d a g r i c u l t u r a l o u t p u t b a i t i n g o f u s a b l e l a n e : \ _ i R e d u c e d a g r i c u l t u r a l o u t p u t ( 1 3 ) s e d i m e n t a t i o n o f r e s e r v o i r -H1_S) R e d u c e d d o w n s t r e e m a i l t l o a d R e d u c t i o r o r e l i m i n a t i o n o f p l a n t o r s n i m a l s p e c i e s s w e i g h t on e a r t h ' s c r u s t M a t e r l u b r i c a t i o n Of f a u l t s {_) S t i S f f i c a c i v i t v and e a r t h q u a k e s (_) S e i s m i c a c t i v i t y and e a r t h q u e k e s v__ P r o p e r t v d a m a g e a n d d e a t h s ^BK P r o p e r t y d a m a g e a n d d e a t h s efN) R e d u c e d r e s e r v o i r s t o r e g e t a p a c t v ( R e d u c t i o n o' b a s i n p e r m e a b i l i t y (~) S l u i c i n g o f sec munta 0m S e a l i n g o f s l u i c i n g o u t l e t s ^ D r e d g i n g and g r a -1 e x t r e r t l o n 9, deduced d o w n s t r e e m s i l t l o a n now i n ^ o f do w n s t r e a m Dio*. a Complete i r a w - d o w r F e e d b a c k on f l o o d s t o r a g e c a p a c i : t - i . / '"eedbsc* or h y d r o e l e c t r i c c a p a c i t f e e d b a c k on i r r i g a t i o n c a p a c i t y (esjJ R e d u c t i o n o f seepage l o s s e s R e d u c e d D i o . a c t i v i t y d o w n a t r e a e ,y S h o r t t e r * l o s s o f r e s e r v o i r use ,fjj£ Sea " D r a e - o o w ^ u n a n t i c i p a t e d ear/ I r a v e 1 s u p p l v Column 7) c o s t s Sea " e f e r e n c e S:, ^ i ^ a d u c e d s i l t d e p o s i t i o n 1 i c r e a s e d r i v e r nank • r o s i o i P r e v e n t i o n o f f l o o d s l i t r- os f, 1 i c r e a s e d s u n l i g h t o ene»raion ^ e d u c t i o n o f e s t u a r i n e n u t r i a n t s R e d u c e d d r e d g i n g r e q u i r e m e n t Ir je rci> t t l ng r i v e r banu f ee i c r e a s e n s o i l ' e r t i l i ' y "1(15) D i s s o l u t i o n o f b a s i n m a t e r i a l s ( 1 6 ) E v a p o r a t i o n I M;! I mo r o v e d n a v i g a t i o n i l i - i e s i £ Sank s t a b i l i z a t i o n r e q u i r e m e n t Reduced a g r i c u l t u r a l O utput MB I n c r e a s e o d o w n s tream o i o . a c t i v i t {_ D e c r e a s e c ^ f - 5 h o r a b i o , S C t i v i t ) (_) * a t e r q u a l i t y c h a n u e ( _) R e l e a s e c ' t l u^ed e a t e r s |B| . n a u i t s b l l i t y o f w a t e r f o r d o m e s t i c and i n d u s t r i a l u s e s IK Changes i n r e s e r v o i r d i o t a em Changes i n downstream b i o t a L O U I o f s t o r e d »at«r — t (_) ' m i m e t i c c h a n g e • (<j"P i n c r e a s e i n e ' f e c t i v e f l o o d h a r a r d r e d u c t i o n IBS r e e d b a c < on h y d r o e l e c . c a p a c i t y A F e e d b a c k on i r r i g a t i o n c a p a c i t y {WF F e e o o a c * on n a v i g a t i o n p o t e n t i a l & F e e a o a c k j n r e c r e a t i o n p o t e n t i a l v,_^ see R e f e r e n c e NO. 17 17 ) C l i m a t i c c h a n g e s ( 1 8 ) T h e r m a l s t r a t i f l c e t i o n ( 1 9 ) D a l e y i n s o r i n g w a t e r t e m p e r a t u r e — r i se { 2 1 j D e l a y o f f a l l w a t e r t e m p e r a t u r e d e c l i n e ( 2 1 ) S t a g n a t i o n o f w a t e r ( 2 2 ) G r o " t h o f w a t e r weeds - J c r e a s e d p r e c i p i t a t i o n i p r o v e d d l a e e e a v e c t o r h«bl a t (^ H > j o l i m n l o n o x y g e n d e u l e ' i o r (f£ A n a e r ^ O i c rr>e«lcal c n o i t i o n s ( e g . H^S^ id U v e r t u r n o f r e s e r v o i r wa .e n'e.ease o f f o u l e d w a t e r s t ) f o u l i n ti o' s u r f e c e w a t e r s <aja R e s t o r a t i o n >f ny;olii»nion c x y g e n tgM Long t e r m c h a n g e i n b i o t a Wk I m p r o v e d a g r i c u l t u r a l o u t p u t <e9' D i s e a s e i, man and a n i m a l ) Reduced b i o . a c t i v i t y b e l o w th e rmoc 1i ne ( ) Reduc e d b i o , a c t i v i t y d o w n s t r e a m {Wf R e d u c e d b i o . a c t i v i t y i n l a k e (SJf) R e s t o r a t i o n o f deep w a t e r o i o . a c t i v i t y )) ' e l a y i n i c e 3r«ak-up D e l a y i n i c e f o r m a i o n P r e v e n t i o n o f i c e f o r m a * l o -0«ygen d e p l e t i o n C r o w t h o f w a t e r weeds P r e v e n t i o n c f i c e s c o u r i }) decrease i n r e s e r v o i r s t o r e g e volume ( 2 3 ) L a n d w a r d l i t t o r a l f o r m a t i o n ( 2 A ) L i n e a l l i t t o r a l f o r m a t i on ( 2 5 ) Change o f g r o u n d w a t e r t a b l e (2_6) S t a b i l i z a t i o n o f impounded w a t e r 27) I n u n d a t i o n o f s c e n i c and h i a t o r i c s i t e s 28) D e c r e a s e d c r o s s r i v e r a c c e s s ( 2 9 ) L o w e r e d s i l t b e a r i n g c a p a c i t y {WA J b s t a c l e on w a t e r s u f r a c e (eW a l o c x i n g o f a p i l l w e y s and l n t a < e * S e a l i n g o f l o w e r w e t e r s I n c r e a s e d e v a p o r e t i o n Oxygen D e p l e t i o n (—J P r o v i s i o n o f h a b i t a t f o r m i c r o - o r g a n i s m s (B t a b ! 1 i z a t i o n o f .water (B P r o m o t i o n o f d i s e a s e v e c t o r s Changes :i n d o w n s t r e a m b i o t a L e n g t h e n i n g o f w i n t e r D e l a y o f r i v e r n a v i g a t i o n .ewW Changes i n do w n s t r e a m b i o t a [W) t x t e n s l o n i o f r i v e r n a v i g a t i o n 40 Growth o f r i v e r weeds ^iV) R e d u c e d b i o l o g i c a l a c t i v i t y 0 See R e f e r e n c e Mo. 22 Feedback on f l o o d s t o r a g e c a p a c i t y ^ F e e d o a c k on h y d r o e l e c t r i c c a p a c i t y ^ F e e d b a c k cn i r r i g a t i o n c a p a c i t y (fj^ ) • e e d b a c k on n a v i g a t i o n p o t e n t i a l ^ F e e d b a c k on r e c r e a t i o n p o t e n t i a l F e e d b a c k on h w d r o e l e c . g e n e r a t i o n W>) Taedback on i r r i g a t i o n s u p p l y ^Bj) R e d u c e d b i o . a c t i v i t y i n l a k e ^ F i s h l o s s e s I n c r e a s e i n e f f e c t i v e f l o o d h a z a r d r e d u c t i o n f) ( e e d b e - k on h y d r o e l e c t r i c c a p a c i t y _) F e e d b a c k on i r r i g a t i o n c a p a c i t y (*_) P r o v i s i o n o f n u t r i e n t s f o r h i g h e r f o r m s s u c h as f i s h K9?I See R e f e r e n c e mo. 26 }) l e a c h f o r m a t i o n fj E r o s i o n o f s n o r e f a c i l i t i e s ^ d e a c h f o r m a t i o n E r o s i o n o f p r o m o n t o r i e s F i l l i n g o f b a y s L r o s i o n o f s h o r e f a c i l i t i e s <0W) Improved r e c r e a t i o n p o t e n t i a l F o u n d a t i o n s t a b i l i z a t i o n r e q u i r e d ^ I m p r o v e d r e c r e a t i o n p o t e n t i a l I) L o s s o f b r e a k w a t e r e f f e c t on s h o r e \) L o s s of s h e l t e r e d w a t e r I) f o u n d a t i o n s t a b i l i z a t i o n r e q u i r e d (_) F o r m a t i o n o f s h o r e l i n e swamps |P P r o m o t i o n o f d i s e a s e v e c t o r s C henges i n I n c i d e n c e o f d i s e a s e v e c t o r s -(sj^) B r e e d i n g o f s n a i l s I n c r e a s e d i n c i d e n c e o f o i l h a r z i a (fjjas) B r e e d i n g o f m o s q u i t o e s (s^Sj I n c r e a s e d i n c i d e n c e of - n a l a r l a _) S h o r e l i n e v e g e t a t i o n c h a n g e s M See R e f e r e n c e No. 26 2 Humen d e a t h s and s u f f e r i n g Human d e a t h s and s u f f e r i n g , l i v e s t o c k and game l o s s e s I n c r e a s e d i n c ' . o f t r y p a n o s o m i a s i s (B) -<uman d e a t h s and s u f f e r i n g l i v e s t o c k and game l o s s e s R e d u c t i o n i n b r e e d i n g o f b l a c k f l y #; R e d u c e d i n c ' . o f o n c h o c e r c i a s i s I m p r o v e d p u b l i c h e a l t h (£) B r e e d i n g o f t s e t s e f l y (_) D e p o s i t i o n a t d o w n s t r e a m t r i b -u t a r y c o n f l u e n c e s ( ) C h o k i n g o f d o w n s t r e a m b i o t a (30_) I n c r e a a a d e s t u a r i n e s a l i n i t 31) L o w e r i n g o f e s t u a r i n e o r d e l t a c h a n n e l s , m a r s h e s , l a k e s , e t c . 22'Reduced e s t u a r i n e s t r a t i f i c a t i o n (3_3) Lower l n g o f r i v e r bank w a t e r t a o l e ( 3 4 ) C r e a t i o n of wide swampy b a a c h (_) B i o l o g i c a l h a b i t a t c h a n g e s (_•) d r e a k down of f o o d c h a i n V_; D e c r e a s e i n e s t u a r i n e n u t r i e n t p r o d u c t i o n {&) V e g e t a t i o n c h a n g e s fjaa) i c e f o r m a t i o n t o b o t t o m ^a) L x p o s u r e o f s p a w n i n g beds f^*) E x p a n s i o n o f i n s e c t B r e e d i n g a r e a L o s s o f f o o d f o r h e r b i v o r s (ajW) E l i m i n a t i o n o f a i o l o g l c a l h a b i t a t (flB F i s h l o s s e s { I n c r e a s e d b o t t o m o x y g e n l e v e l (_) V e g e t a t i o n c h a n g e s (_) D r y i n g o f a g r i c u l t u r a l l a n d ( 35_) B l o c k i n g o f anadromous f i s h ( 3 6 ) Emergence o f anadromous f i s h f r o m f i s h l a d d e r i n t o r e s e r v o i r p*:) L x p o s u r e o f s p a w n i n g oeds 'faV) K i l l i n g o f a q j a t i c weeds (_) B r e a k down of p r e d a t o r - p r e y f i s h r e l n t i o n s h i p s 4jf£) i t r a n d i n g o f n a v i g a t i o n a l f a c i l i t i e s ef^ B r e e d i n g o f i n s e c t s B u i l d i n g o f f i s h l a d d e r s ((P; Some f i s h m i s s l a d d e r e n t r a n c e s g C u r r e n t sweeps f i s h o v e r C o n f u s i o n and d e l a y I n r dam e s e r v o i r 9jftt I r r e t r i e v a b l e c u l t u r a l l o s s B r e a k down o f s o c i a l c o n t a c t p a t t a r n s H S i l t i n g o f bank f a c i l i t i e s \) R e d u c e d b i o . a c t i v i t y d o w n s t r e a m (_) E s t u a r i n e s p e c i e s c h a n g e s (_) R e d u c e d b i o . a c t i v i t y o f f - s h o r e E l i m i n a t i o n o r r e d u c t i o n o f a n i m a l p o p u l a t i o n s (IP) E l i m i n a t i o n o r r e d u c t i o n o f f i s h and a n i m a l p o p u l a t i o n s M l D e c l i n e o f c o m m e r c i a l f i s h e r y tfB) I n s e c t i n c r e a s e s . See R e f e r e n c e No. 34 {W) I n s e c t i n c r e a s e s , See R e f e r e n c e NO. 34 (__) I n c r e a s e d e s t u a r i n e b i o . a c t i v i t y ( ) A n i m a l p o p u l a t i o n c h a n g e s (_) L o s s o f g r a z i n g l a n d ( ) I r r i g a t i o n r e q u i r e m e n t (_) R e d u c e d a g r i c u l t u r a l o u t p u t iSSt F e e d b a c k on r e c r e a t i o n p o t e n t i a l (_) R e d u c t i o n o r e l i m i n a t i o n o f f i s h p o p u l a t i o n s (_) R e d u c t i o n o r e l i m i n a t i o n o f f i s h p o p u l a t i o n s S I m p r o v e d b e a c h a e s t h e t i c s E l i m i n a t i o n o f m i c r o - o r g a n i s m h a b i t a t F e e d b a c k on n a v i g a t i o n p o t e n t i a l S t Human n u i s a n c e and d i s e a s e ( ) L o s s o f l i v e s t o c k and w i l d l i f e E l i m i n a t i o n o f f i s h p o p u l a t i o n R e d u c t i o n o f f i s h p o p u l a t i o n ( 37) P a s s a g e o f f r y o v e r s p i l l w a y o r t h r o u g h t u r b i n e s ( C o n f u s i o n o f d o w n s t r e a m m i g r a n t s ( 39 ) R e d u c t i o n o f s p a w n i n g bed a r e a ( 4 o ) I n c r e a s e d d o w n s t r e a m t e m p e r a t u r e (41 ) D o w n s t r e a m o x y g e n l e v e l r e d u c t i o n ( 1 2 ) C h a n g e s i n s i l t a t i o n p a t t e r n s p) S u b s t a n t i a l f i s h l o s s e s {W) D e l a y o f m i g r a t i o n I; F a i l u r e t o m i g r a t e d o w n s t r e a m C r o w d i n g M e t a b o l i c c h a n g e s f o r f i s h >eath i d u c t i o n o f s u c c e s s f u l s p a w n i n g (_) S u f f o c a t i o n o f do w n s t r e a m s p a w n i n g b e d s (_) S u f f o c a t i o n o f f i s h e g g s D e a t h o f o l d f i s h b e f o r e s p a w n i n g R e d u c t i o n o f s u c c e s s f u l s p a w n i n g R e d u c t i o n o f f i s h p o p u l a t i o n M o d i f i c a t i o n o f f i s h l i f e c y c l e R e d u c t i o n o f f i s h p p p u l a t i o n QW) R e d u c t i o n o f f i s h p o p u l a t i o n E l i m i n a t i o n o f f i s h p o p u l a t i o n R e d u c t i o n o f f i s h p o p u l a t i o n (_) R e d u c t i o n o f f i s h p o p u l a t i o n ( ) R e d u c t i o n o f f i s h p o p u l a t i o n M O R A N D A M P R O P O S A L e > * O B J E C T I V E S F l o o d h a z a r d r e d u c t i o n H y d r o e l e c t r i c g e n e r a t i o n 4f^--I r r i g a t i o n s u p p l y N a v i g a t i o n R e c r e a t i o n -LEGEND H i g h l y p r o b a b l o a f f e c t s U n c e r t a i n e f f e c t s h i g h l y i m p r o b a b l e e f f e c t s F I G U R E B 

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