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Chapter 1 Historical Introduction
1
Chapter 1
HISTORICAL INTRODUCTION
1.1
SOURCE OF THE NILE
The known h i s t o r y o f t h e N i l e R i v e r d a t e s b a c k t o j u s t b e f o r e 5000 B . C . From t h e n t i l l r e c e n t l y v a r i o u s t h e o r i e s a b o u t t h e s o u r c e o f t h e N i l e and i t s
r i s e h a v e b e e n l a i d down. Some of t h e s e t h e o r i e s were s o c o n f l i c t i n g t h a t i t became c u s t o m a r y i n a n c i e n t Rome t o s a y : q u a e r e r e f o n t e s N i l e ( s e a r c h for t h e N i l e ) when someone t a l k e d a b o u t a m y s t e r i o u s or i m p o s s i b l e matter ( P i e r r e , 1974). The name N i l e i s s a i d t o b e d e r i v e d f r o m t h e G r e e k N e i l o s , whose o r i g i n i s unknown. B o t h N e i l o s and A i g u p t o s ( m a s c u l i n e ) w e r e u s e d i n G r e e k drama when r e f e r r i n g t o t h e N i l e , w h e r e a s A i g u p t o s ( f e m i n i n e ) a l o n e was u s e d when r e f e r r i n g t o Egypt ( E n c y c lo p a e d ia B r i t a n n i c a ,
1969).
I t i s o f t e n c l a i m e d t h a t t h e a n c i e n t E g y p t i a n s knew n o t h i n g o f t h e o r i g i n of t h e i r r i v e r . T h i s c l a i m i s s u p p o r t e d o n o n e h a n d by t h e n a i v e c o n v i c t i o n o f t h e common a n c i e n t E g y p t i a n t h a t t h e N i l e f l o w s o u t o f t h e f u l l b r e a s t s o f t h e N i l e God, H a p i . The p r i e s t s o f a n c i e n t E g y p t , o n t h e o t h e r h a n d , h a d t h e i r own t h e o r y , w h i c h t h e y f a i t h f u l l y f o u n d e d o n t h e o l o g i c a l g r o u n d s . T h o s e p r i e s t s were c o n v i n c e d t h a t somewhere t h e c o u r s e o f "The C e l e s t i a l N i l e " w a s b e s e t by m o n s t r o u s r o c k s and s t o n e s and t h a t b e l o w t h i s b a r r i e r rose E g y p t ' s N i l e or E g y p t ' s h e a v e n - d e s c e n d e d s t r e a m . A f t e r a l l , t h e N i l e p r i e s t s were one of t h e s o u r c e s t h a t provided Herodotus, t h e I o n i a n , w i t h m o s t o f t h e informat i o n t h a t a p p e a r e d i n h i s w r i t t e n a c c o u n t s on Egypt and t h e N i l e . The p h i l o s o p h e r s and s a v a n t s o f a n c i e n t Greece h a d t h e i r v i e w s o n , and o p i n i o n s o f , t h e s o u r c e o f t h e N i l e and o f i t s r h y t h m i c p a t t e r n o f f l o w . T h e s e views comprised t h e r o l e o f t h e E t e s i a n ( n o r t h e r l y ) winds i n t h e bui l d-up o f the N i l e ,
t h e o r i g i n o f t h e r i v e r from Oceanus ( t h e ocean s u r r o u n d i n g t h e
e a r t h ) , and t h e r i s e o f t h e N i l e f r o m t h e p e a k s o f t h e L y b i a n m o u n t a i n s and
i t s s u p p l y f r o m t h e m e l t e d snow t h e r e o n . H e r o d o t u s w r o t e i n h i s a c c o u n t s t h a t , d u r i n g h i s v i s i t t o Egypt i n 457 B . C . ,
one informant s a i d t h a t t h e Nile r o s e
from a p o w e r f u l s p r i n g f e e d i n g a d e e p l a k e s i t u a t e d b e t w e e n t h e h i l l s o f Mophi and C h r o p h i . T h e r e a r e two t r a i n s o f t h o u g h t :
t h e f i r s t is t h a t t h e
s a i d l a k e l i e s b e t w e e n t h e i s l a n d o f E l e p h a n t i n e and Aswan, w h i c h c o n f i n e s t h e w h o l e s t o r y t o t h e N i l e i n E g y p t , and t h e o t h e r i s t h a t t h e l a k e i s s i t u a t e d f a r more t o t h e s o u t h . I n c o m p a r i s o n w i t h r e c e n t d i s c o v e r i e s t h e l a t t e r i s s o m e t i m e s i n t e r p r e t e d as t h e l a k e s u p p l y i n g t h e S e m l i k i R i v e r which d i s c h a r g e s
i t s w a t e r i n t o Lake A l b e r t ( a l s o c a l l e d Mobutu-Sese S e k o ) . I f w e a r e prepared t o accept t h i s i n t e r p r e t a t i o n ,
i t is then f a i r t o conclude t h a t
Herodotus c a n b e complimented f o r t h r o w i n g some l i g h t on t h e w e s t e r n t r i b u t a r y o f t h e N i l e R i v e r . I n a p a p e r e n t i t l e d "The N i l e , i t s O r i g i n and R i s e "
it is
mentioned t h a t H e r o d o t u s b e l i e v e d t h a t t h e Upper N i l e flowed from w e s t t o e a s t , b u t h e c o n f u s e d t h e Niger w i t h t h e N i l e ( B i s w a s , A . , f o r q u i t e some t i m e . J u b a I 1 (20 A . D . ) ,
1966). T h i s i d e a p r e v a i l e d
t h e King o f M a u r i t a n i a , a f f i r m e d t h a t
t h e s o u r c e of t h e N i l e was i n w e s t e r n A f r i c a , t h e r e b y s u p p o r t i n g t h e c o n v i c t i o n t h a t t h e N i g e r i s a b r a n c h of t h e N i l e ( B i s w a s , A , , The Greek p h i l o s o p h e r A r i s t o t l e (384-322 B . C . )
1966, 1970).
thought t h a t t he r i v e r
descended from a mountain of s i l v e r (montagne d ' a r g e n t ) and t h a t heavy s p r i n g and summer r a i n s on t h e h i g h l a n d s of t h e catchment a r e a s (what we c a l l nowadays t h e B l u e and White N i l e s ) were r e s p o n s i b l e f o r t h e flow i n t h e N i l e . Almost two c e n t u r i e s a f t e r H e r o d o t u s , came t h e m a t h e m a t i c i a n and g e o g r a p h e r E r a t o s t h e n e s (276-194 B . C . ) who d e s c r i b e d t h e N i l e f a r b e t t e r t h a n any of h i s p r e d e c e s s o r s . H i s i d e a w a s t h a t two p r i n c i p a l streams s p r a n g o u t o f some l a k e s s i t u a t e d t o t h e e a s t and e n c i r c l e d Meroe, a c o n s i d e r a b l y l a r g e i s l a n d ( s e e map, F i g . 1 . 1 . ) . The e a s t e r n t r i b u t a r y was t h e A s t a b o r a s (now c a l l e d t h e A t b a r a ) and t h e w e s t e r n t h e A s t a s o b a s (now c a l l e d t h e B l u e N i l e ) . The Astapus
(now c a l l e d
t h e White N i l e ) was a d i f f e r e n t r i v e r e n t i r e l y , which r o s e from some l a k e s t o t h e s o u t h and c a r r i e d t h e summer r a i n s t o form t h e d i r e c t stream of t h e N i l e . P t o l e m y , t h e Roman, who l i v e d i n A l e x a n d r i a i n t h e s e c o n d c e n t u r y A . D . , t h o u g h t t h a t t h e main N i l e came from t h e Mountains of t h e Moon, which w e r e p e r m a n e n t l y c o v e r e d w i t h snow and p a s s e d t h r o u g h two l a k e s . I t i s p r o b a b l e t h a t h e meant by t h e Mountains of t h e Moon, t h e Ruwenzori r a n g e and by t h e two l a k e s , V i c t o r i a and A l b e r t Nyanza. The map of t h e N i l e a s d e v e l o p e d by Ptolemy
i s a s shown i n F i g . 1.2. From t h e s e c o n d h a l f o f t h e s e c o n d c e n t u r y o n w a r d s , f o r a t l e a s t t h i r t e e n c e n t u r i e s , t h e r e w e r e h a r d l y any d i s c o v e r i e s , w i t h t h e e x c e p t i o n of some d e s c r i p t i o n s o f t h e lower r e a c h e s o f t h e N i l e by t h e mosl m g e o g r a p h e r s i n E g y p t . Examples a r e Al-Khuwarazmi
i n 864 A . D .
and Al-Masoudy
n 957 A . D .
The t r i u m p h a n t wars of P o r t u g a l a g a i n s t t h e Moors i n n o r t h - w e s t
Africa i n
t h e f i f t e e n t h c e n t u r y h a d , no d o u b t , paved t h e r o a d t o t h e P o r t u g u e s e i n f i l t r a t i o n i n A f r i c a , b o t h e a s t and w e s t . Two P o r t u g u e s e m i s s i o n a r i e s , P e d r o Paez and Jerome Lobo, v i s i t e d E t h i o p i a i n t h e s e v e n t e e n t h c e n t u r y . F a t h e r Paez v i s i t e d Lake Tana ( 1 6 1 8 ) . H i s s u c c e s s o r , F a t h e r Lob0 w r o t e an a c c o u n t a b o u t h i s v i s i t t o T i s s i s a t F a l l s . About 150 y e a r s l a t e r , i n 1770 A . D . ,
a Scottish
e x p l o r e r named James B r u c e , a f t e r h a v i n g j o u r n i e d f i v e y e a r s i n E t h i o p i a , s u c c e e d e d i n d i s c o v e r i n g t h e s o u r c e of t h e l i t t l e Abbai ( s e e map, F i g . 1 . 1 . ) . A summary of B r u c e ' s views on Paez and Cheesman's on t h e e x p e d i t i o n of Bruce
c a n be found i n t h e Book on The B l u e N i l e (Moorehead, A , ,
1962).
3
F i g . 1.1. L o c a t i o n o f t h e o l d i s l a n d o f Mero and t r i b u t a r i e s
The j o u r n e y s made by t h e Arab t r a d e r s on t h e e a s t c o a s t o f A f r i c a t o t h e i n t e r i o r , t h e r e l i g i o u s m i s s i o n s t o E a s t A f r i c a and t h e s t e a d i l y growing conn e c t i o n s between t h e C o p t i c c h u r c h e s o f A l e x a n d r i a and E t h i o p i a have a l l l e d t o more c o n c r e t e i n f o r m a t i o n on t h e snow-capped m o u n t a i n s ( t h e Mountains of t h e Moon) d e s c r i b e d by Ptolemy i n 150 A . D . The h i s t o r y o f e x p l o r i n g t h e N i l e r i v e r s y s t e m i n t h e n i n e t e e n t h c e n t u r y b e g i n s w i t h t h e i n v a s i o n of t h e Sudan by Mohammed A l i Pasha and h i s s o n s from 1821 onwards. A s a r e s u l t of t h i s , t h e B l u e N i l e was e x p l o r e d a s f a r a s i t s
e x i t from t h e E t h i o p i a n f o o t h i l l s , and t h e White N i l e a s f a r a s t h e S o b a t mouth. The Bahr e l Ghazal w a s e x p l o r e d by P e t h e r i c k i n t h e e i g h t e e n f i f t i e s . The c o n s i d e r a b l e i n t e r e s t o f t h e Europeans came s h o r t l y a f t e r t h e r e p o r t s o f Knoblecher (1850) a b o u t t h e e x i s t e n c e of some l a r g e l a k e s i n t h e s o u t h .
4
The M o u n t a i n s of the Moon
)
Second Lake
\
F i r s t Lake
) T h e holy Sprinq
v&&Donkola "
Aswan
Upper Land
"
K?
I
t
" M i d d i e Land
"
Asiut
A l - Ashmunein
A l - Muqattam
Mediterranean
Sea
I
F i g . 1 . 2 . Map of t h e N i l e from t h e s o u r c e a t t h e Mountains of t h e Moon t o t h e mouth i n t h e M e d i t e r r a n e a n S e a , a s p r e p a r e d by Ptolemy
From a b o u t 1857 onwards for a b o u t 30 y e a r s , t h e E q u a t o r i a l Lakes P l a t e a u and s u r r o u n d i n g s w e r e t r a v e r s e d by s e v e r a l e x p l o r e r s ,
a l l s e a r c h i n g for t h e
s o u r c e of t h e r i v e r t h a t h a d p u z z l e d t h e whole w o r l d for s e v e r a l c e n t u r i e s . The p r i n c i p a l e x p l o r e r s and t h e i r e x p e d i t i o n s w e r e as f o l l o w s : i)
B u r t o n and Speke went from Bagamoyo t o Tabora t o U j i j i on Lake Tanganyika (1857-59). I n 1858 Speke a l o n e went on n o r t h w a r d s and d i s c o v e r e d Lake V i c t o r i a .
5
S p e k e and G r a n t s e t o f f on an e x p e d i t i o n (1860-63)
ii)
around Lake V i c t o r i a
and r e a c h e d Ripon F a l l s . They t h o u g h t t h a t t h e stream f l o w i n g o u t of t h i s l a k e was t h e s o u r c e o f t h e N i l e . i i i ) Samuel B a k e r , a f t e r e x p l o r i n g t h e A t b a r a , went on t o d i s c o v e r Lake A l b e r t (1862-64)
a s w e l l a s t h e A l b e r t N i l e and t h e u p p e r r e a c h of
Bahr e l J e b e l . L i v i n g s t o n e , l i k e B u r t o n and S p e k e , s e t o f f on h i s r o u t e from Tabora
iv)
to U j i j i
( 1 8 7 2 ) . H e t h o u g h t t h e Lake Nyasa m i g h t b e d r a i n i n g i n t o Lake
T a n g a n y i k a , which c o u l d t h e n b e l i n k e d w i t h t h e A l b e r t Lake and t h e N i l e . v)
S t a n l e y t r a v e l l e d up from t h e e a s t c o a s t and c i r c u m n a v i g a t e d Lake V i c t o r i a ( 1 8 7 2 ) . H i s a t t e m p t t o g e t t o Lake A l b e r t was n o t s u c c e s s f u l , though h e r e a c h e d as f a r a s t h e e s c a r p m e n t a b o u t Lake George. I n a l a t e r j o u r n e y ( 1 8 8 9 ) h e r e a c h e d t h e S e m l i k i and Lake Edward. The r o u t e s o f t h e s e l e a d i n g e x p l o r e r s a r e i n d i c a t e d o n t h e map, F i g . 1 . 3 .
(Stamp and Morgan, 1 9 7 2 ) . I n s p i t e o f a l l t h e e x p e d i t i o n s a l r e a d y m e n t i o n e d , a number of t r i b u t a r i e s o f t h e N i l e remained u n d i s c o v e r e d . E x p l o r a t i o n m i s s i o n s s t o p p e d i n t h e p e r i o d 1881 up t o 1898 a s a r e s u l t o f t h e r e b e l l i o n s o f t h e Mahdis i n t h e S u d a n . A h i s t o r i c a l a c c o u n t o f t h i s p e r i o d c a n b e found i n t h e book e n t i t l e d "The White Nile"
(Moorehead, A , ,
1 9 6 0 ) . A f t e r t h e r e o p e n i n g of t h e Sudan i n 1898 and a t
a b o u t t h e same t i m e t h e o p e n i n g up o f Kenya and T a n z a n i a ( f o r m e r l y c a l l e d T a n g a n y i k a ) and Uganda, i r r i g a t i o n s e r v i c e s and s u r v e y and g e o l o g i c a l d e p a r t ments were e s t a b l i s h e d i n t h e r e s p e c t i v e c o u n t r i e s . S i n c e t h e n t h e s e d e p a r t ments h a v e t a k e n o v e r t h e e x p l o r a t o r y work a s w e l l a s t h e c o l l e c t i o n of h y d r o l o g i c and o t h e r r e l e v a n t d a t a ( H u r s t , H . ,
1952).
A t a b o u t t h e end o f 1902 t h e I r r i g a t i o n Department o f Egypt s t a r t e d two e x p e d i t i o n s ; t h e one u n d e r M r C . E .
Dupuis t o v i s i t Lake Tana and t h e o t h e r
u n d e r S i r W . G a r s t i n t o v i s i t t h e Lakes V i c t o r i a and t h e t h e n A l b e r t and Edward. The e x p e d i t i o n s which f o l l o w e d w e r e s e n t t o c o l l e c t , or r e p o r t o n , h y d r o l o g i c a l d a t a needed f o r t h e N i l e p r o j e c t s ( H u r s t , H . E . ,
1 9 3 1 ) . Unfortun-
a t e l y , t h e M a c m i l l a n - J e s s e n e x p e d i t i o n s i n 1902 and 1905 f a i l e d i n e x p l o r i n g Lake Tana o r f i n d i n g t h e s o u r c e o f t h e B l u e N i l e . A f t e r t h i s t h e r e was a l o n g p e r i o d o f i n a c t i v i t y on t h e r i v e r u n t i l R . E .
Cheesman a r r i v e d i n 1925 i n
E t h i o p i a . F o r t h e n e x t e i g h t y e a r s Cheesman d e v o t e d h i m s e l f t o t h e e x p l o r a t i o n o f t h e g o r g e o f t h e B l u e N i l e and t o c i r c u m n a v i g a t e Lake Tana. T h i s accomplishment was t e r m i n a t e d by w r i t i n g an a c c o u n t on Lake Tana and t h e B l u e N i l e (Cheesman, R . ,
1936).
More r e c e n t e x p e d i t i o n s h a v e b e e n s e n t , e s p e c i a l l y by t h e E g y p t i a n Governm e n t , t o e x p l o r e more o f t h e t r i b u t a r i e s i n t h e c a t c h m e n t s of t h e E q u a t o r i a l L a k e s , t h e White N i l e and t h e S o b a t . However, i t was n o t u n t i l 1937 t h a t t h e
6
southernmost s o u r c e of t h e N i l e i n t h e headstreams of t h e Kagera, l a r g e s t trib u t a r y o f Lake V i c t o r i a , was l o c a t e d . F u r t h e r e x p l o r a t i o n o f t h e N i l e t r i b u t a -
r i e s i n t h e E t h i o p i a n P l a t e a u h a s b e e n f o r q u i t e some t i m e l e s s f o r t u n a t e t h a n t o o t h e r p a r t s o f t h e N i l e B a s i n . The g o r g e o f t h e B l u e N i l e ( G r e a t A b b a i ) was n o t f u l l y t r a v e r s e d u n t i l a B r i t i s h m i l i t a r y and s c i e n t i f i c e x p e d i t i o n c o n quered i t d u r i n g t h e f l o o d o f 1968 ( B l a s h f o r d - S n e l l , J . N . ,
- - -Burton - - -Speke +++++
N
8, Speke 1857-'59
1858
Speke & Grant 1860-'63
.. ....... -
----
1970).
Baker Stanley
1862-'64 1871-'72, 1874-'77 8, 1887 - '8 9 L i v i n g s t o n e 1872
b Bagamoyo Tabora r o u t e s ~ m ~ l afor r Speke & Grant a n d S t a n l e y
F i g . 1 . 3 . The r o u t e s o f some l e a d i n g e x p l o r e r s o f t h e N i l e S o u r c e ( S t a m p , L . D . and Morgan, W.T., 1 9 7 2 )
1.2 1.2.1
HISTORY O F HYDROLOGY OF THE NILE BASIN
From 3200 B . C . t o 1900 A . D .
W h e t h e r t h e a n c i e n t E g y p t i a n s knew t h e o r i g i n o f t h e i r r i v e r or n o t ,
( s e e 1.1) w h a t c a n n o t b e d e n i e d i s t h a t t h e y were d e e p l y k e e n t o o b s e r v e a l l a s t r o n o m i c a l phenomena and t e r r e s t r i a l e v e n t s a s s o c i a t e d w i t h , o r r e l a t e d t o , the N i l e floods,
7
One of t h e most a n c i e n t r e c o r d s i s a drawing of an i m p e r i a l macehead h e l d by t h e p r o t o d y n a s t i c k i n g S c o r p i o n when c e l e b r a t i n g t h e o c c a s i o n of c u t t i n g an i r r i g a t i o n d i t c h some 3200 y e a r s B . C .
(Biswas, A . ,
1 9 7 0 ) . The same r e f e r -
e n c e m e n t i o n s , among o t h e r s : damming o f f of t h e N i l e and d i v e r t i n g i t s c o u r s e by King Menes i n 3000 B . C .
A t t h e same t i m e t h e a n c i e n t E g y p t i a n s began t o u s e
t h e N i l o m e t e r s t o r e c o r d t h e f l u c t u a t i o n of
t h e const r uct i on of
( P a g a n t s dam) some 30 k i l o m e t r e s s o u t h of C a i r o and i t s f a i l u r e
Sadd e l - K a f a r a i n 2850 B . C . ,
the N i l e ,
t h e c o n n e c t i o n o f t h e N i l e and t h e Red S e a by a n a v i g a t i o n a l
c a n a l d u r i n g t h e r e i g n of S e o s t r i s I i n a b o u t 1950 B . C . ,
t h e h y d r a u l i c works
of Amenemhet I 1 1 ( i n c l u d i n g Lake M o e r i s ) i n a b o u t 1850, t h e w a t e r codes of King Hammurabi i n 1750 B . C . , d e e p ) i n a b o u t 1700, e t c .
J o s e p h ' s w e l l n e a r C a i r o (more t h a n 100 metres
(Biswas, A , ,
1 9 7 0 ) . Another r e f e r e n c e s t a t e s t h a t
" h y d r a u l i c e n g i n e e r i n g " a t t h a t t i m e r e a c h e d a h i g h d e g r e e of accomplishment; r e c l a m a t i o n schemes on t h e l e f t bank of t h e N i l e were i n i t i a t e d d u r i n g t h e f l o o d s ; dams, d i k e s and c a n a l s w e r e c o n s t r u c t e d and l a t e r w a t e r - l i f t i n g machinery was i n v e n t e d ( T e c l a f f and T e c l a f f , 1 9 7 3 ) . Probably t h e f i r s t n o n - r e l i g i o u s
t h e o r y e x p l a i n i n g t h e y e a r l y f l o o d i n g was
t h a t d e r i v e d by t h e Greek T h a l e s (600 B . C . ) ,
t h e f o u n d e r of d e d u c t i v e geo-
m e t r y . H i s t h e o r y was t h a t t h e E t e s i a n winds d r o v e t h e s e a h i g h a g a i n s t t h e mouths of t h e r i v e r and t h e r e u p o n p r e v e n t e d them from d i s c h a r g i n g t h e i r w a t e r . The r i v e r t h e r e f o r e r e t u r n e d upon i t s e l f and, whenever i t c o u l d , i t b u r s t o u t i n t o f o r b i d d e n g r o u n d . A c o u p l e of c e n t u r i e s l a t e r a n o t h e r Greek g e o m e t e r , D e m o c r i t u s , came up w i t h a somewhat d i f f e r e n t t h e o r y . H e t h o u g h t t h a t when snow i n t h e n o r t h e r n p a r t s o f t h e w o r l d was m e l t e d a t t h e t i m e of t h e s u m m e r s o l s t i c e and flowed away, c l o u d s w e r e formed by t h e v a p o u r . When t h e c l o u d s
w e r e d r i v e n towards t h e s o u t h and towards Egypt by t h e E t e s i a n w i n d s , v i o l e n t s t o r m s a r o s e and c a u s e d t h e l a k e s f e e d i n g t h e R i v e r N i l e t o be f i l l e d (Frisinger, H . ,
1959).
S i n c e t h e N i l e u s e d t o r i s e i n f l o o d a t a b o u t t h e same t i m e e v e r y y e a r , i t s b e h a v i o u r had b e e n d e s c r i b e d a s r e g u l a r . The B i b l e t e l l s u s , however,
"
....
t h e r e came s e v e n y e a r s o f g r e a t p l e n t y t h r o u g h o u t t h e l a n d of E g y p t . And t h e r e s h a l l r i s e a f t e r them s e v e n y e a r s o f f a m i n e
.."
( G e n e s i s 4 1 , 29-30).
The i n t e r -
p r e t a t i o n by J o s e p h t o t h i s dream o f t h e P h a r a o of Egypt was p r o b a b l y t h e f i r s t indication of the persistence i n the hydrologic t i m e s e r i e s . The Roman s a v a n t , P l i n y (23-79 A . D . ) ,
t h o u g h t t h e two p r o b a b l e t h e o r i e s
a b o u t t h e f l o o d i n g of t h e N i l e w e r e t h o s e o f T h a l e s and Democritus.
After a l l ,
i n b o t h t h e o r i e s t h e a c t i o n of t h e E t e s i a n winds was t h e c u l p r i t . A f t e r P l i n y , t h e E n g l i s h h i s t o r i a n and t h e o l o g i a n , Beda (674-735 A . D . ) ,
compiled and sum-
m a r i z e d t h e knowledge t h e n a v a i l a b l e a b o u t t h e N i l e f l o o d . The t h e o r y h e p r o p o s e d was v e r y s i m i l a r t o t h a t of T h a l e s . H e c l a i m e d t h a t t h e n o r t h e r l y
8
winds f o r c e d t h e s e a waves t o p i l e up s a n d a t t h e N i l e mouths, t h u s c a u s i n g t h e r i v e r t o back up upon i t s e l f and f l o o d ( F r i s i n g e r , H . ,
1 9 5 9 ) . From t h a t
t i m e onwards u n t i l t h e n i n e t e e n t h c e n t u r y t h e r e was v e r y l i t t l e done t o e x p l o r e t h e s o u r c e s o f t h e N i l e and i t s t r i b u t a r i e s , e x c e p t f o r t h e r e c o r d i n g s which
w e r e done whenever p o s s i b l e . The n i n e t e e n t h c e n t u r y was t h e c e n t u r y of d i s c o v e r i n g t h e N i l e s o u r c e and t r i b u t a r i e s r a t h e r t h a n c o l l e c t i n g a n d / o r i n t e r preting its hydrologic data. The r e c o r d of t h e N i l e l e v e l s d a t e s back t o a b o u t 3000 t o 3500 y e a r s B . C . The r i v e r gauge is. c a l l e d N i l o m e t e r ( i n A r a b i c Miqyas An-Nil).
Three t y p e s of
N i l o m e t e r s were u s e d . The f i r s t t y p e c o n s i s t e d s i m p l y o f marking t h e w a t e r l e v e l s on c l i f f s on t h e banks of t h e r i v e r , e . g . t h e s e c o n d c a t a r a c t a t Semna. The s e c o n d t y p e c o n s i s t e d e s s e n t i a l l y of a s c a l e , u s u a l l y o f m a r b l e , on which t h e w a t e r l e v e l was o b s e r v e d . The s t a n d a r d gauge c o n s i s t e d o f a s e r i e s o f s t e p s
or p i l l a r s b u i l t i n t o t h e r i v e r bank t o e a c h of which a s e c t i o n of t h e s c a l e was f i x e d . I t i s c l a i m e d t h a t t h e r e a r e 140 o f t h e s e gauges s c a t t e r e d o v e r t h e b a s i n o u t s i d e E g y p t , and many more on t h e N i l e i n E g y p t . Most o f them a r e o b s e r v e d d a i l y , and t h e r e a d i n g s o f t h e more i m p o r t a n t a r e t e l e g r a p h e d or t e l e phoned t o C a i r o ( H u r s t , H . E . ,
1 9 5 2 ) . The c a t a s t r o p h i c f l o o d s o f 1954 and 1958
were measured a t 9 3 g a u g i n g p o i n t s i n Egypt o n l y , 36 gauges i n upper Egypt and t h e r e m a i n d e r i n l o w e r Egypt (Hashem and E l - S h e r b i n i ,
1 9 6 1 ) . The t h i r d and most
a c c u r a t e N i l o m e t e r used t o b r i n g w a t e r o f t h e N i l e t o a w e l l and t h e w a t e r l e v e l was marked e i t h e r on t h e w a l l s o f t h e w e l l or on a c e n t r a l p i l l a r . The most n o t a b l e N i l o m e t e r i s s i t u a t e d a t Roda n e a r C a i r o . The r e c o r d e d w a t e r l e v e l t h e r e d a t e s back t o 6 4 1 A . D . t h e r e i n 715 A . D .
The Arab c h a l i p h s (Kings) b u i l t a new N i l o m e t e r
T h i s was r e b u i l t i n 8 6 1 A . D .
I t c o n s i s t s of a squar e w e l l
c o n n e c t e d t o t h e N i l e by means o f t h r e e c o n d u i t s . A t t h e c e n t r e o f t h e w e l l i s a g r a d e d o c t a g o n a l p i l l a r of w h i t e m a r b l e d i v i d e d i n t o 19 c u b i t s (see F i g . 1 . 4 ) . I t was r e p o r t e d t h a t a s a r e s u l t o f p o o r j o i n i n g o f t h e lower b r o k e n p a r t o f t h e p i l l a r , t h e c o r r e s p o n d i n g c u b i t now measures 31 c m o n l y i n s t e a d o f t h e o r i g i n a l 54 c m ( G h a l e b , K., 1 9 3 5 ) . T h i s example and many o t h e r s shows t h a t t h e records a v a i l a b l e s i n c e 641 A . D .
need much a d j u s t m e n t b e f o r e h a v i n g them
a n a l y z e d . The s u i t a b i l i t y o f t h e r e c o r d f o r s t a t i s t i c a l a n a l y s i s h a s b e e n a r g u e d r e c e n t l y : "Simply,
t h e r e l i a b i l i t y of f l o o d d a t a f o r t h e assessment of
w a t e r a v e r a g e s , t h e r e l i a b i l i t y o f p r e s e r v a t i o n o f a l o n g - r a n g e c o n s t a n t gauge datum i n t h e p a s t , and a c c u r a c i e s i n o b s e r v a t i o n s ( a l l k i n d s o f c h a n g e s ) , unf o r t u n a t e l y do n o t p e r m i t one t o draw d e p e n d a b l e c o n c l u s i o n s " .
(Yevjecvich, V . ,
1983). 1.2.2
From 1900 A . D .
t i l l now
The t u r n of t h e l a s t c e n t u r y and t h e b e g i n n i n g o f t h e t w e n t i e t h c e n t u r y w i t n e s s e d a number of n o t a b l e a c c o m p l i s h m e n t s . When t h e t h e n Anglo-Egyptian
9
F i g . 1 . 4 . The N i l e gauge a t Roda, C a i r o , Egypt
10
S u d a n w a s r e o c c u p i e d i n 1 8 9 8 a l l swamp r i v e r s were f o u n d b l o c k e d u p . I t w a s n o t b e f o r e 1 9 0 5 t h a t a c h a n n e l t h r o u g h t h e B a h r e l J e b e l h a d b e e n made c l e a r . The G h a z a l was n o t made n a v i g a b l e t o t h e p r i n c i p a l c a p i t a l Wau, u n t i l 1 9 0 4 . I n 1 9 0 2 t h e w o r k s i n t h e f i r s t Aswan dam and some o f t h e B a r r a g e s o n t h e N i l e i n E g y p t were c o m p l e t e d . The h i s t o r y o f s c i e n t i f i c s t u d y o f t h e h y d r o l o g y
o f t h e N i l e b e g i n s w i t h t h e i n t r o d u c t i o n o f c u r r e n t metres by S i r H . Lyons i n about 1902. Previous t o t h i s ,
f l o w m e a s u r e m e n t s h a d b e e n made by f l o a t s . The
S u r v e y D e p a r t m e n t o f E g y p t became c h a r g e d w i t h t h e s u r v e y o f a l l r i v e r g a u g e r e c o r d s s o u t h o f Aswan i n 1 9 0 2 and 1 9 0 3 . T h i s w a s t h e o r i g i n o f t h e H y d r o l o g y S e r v i c e w h i c h formed p a r t o f t h e l a t e r P h y s i c a l D e p a r t m e n t o f E g y p t ( H u r s t and P h i l i p s , 1931) . The r e s u l t s o f t h e e x p e d i t i o n s t o L a k e s T a n a , V i c t o r i a , A l b e r t and Edward c o n d u c t e d by D u p u i s and G a r s t i n i n 1901-1904
( s e e 1 . 1 ) were c o n c l u d e d i n t h e
1904 r e p o r t by S i r W. G a r s t i n . S h o r t l y a f t e r t h a t , i n 1 9 0 6 , S i r H . Lyons publ i s h e d h i s book "The P h y s i o g r a p h y o f t h e N i l e " .
T h i s book c o n t a i n e d t h e i n f o r -
m a t i o n g a t h e r e d f r o m t r a v e l l e r s and s c i e n t i f i c e x p l o r e r s a v a i l a b l e a t t h a t
time.
I n 1905 S i r M .
MacDonald i n t r o d u c e d a new method o f r i v e r m e a s u r e m e n t a t
Aswan u s i n g t h e f l o w t h r o u g h t h e s l u i c e s o f t h e dam. A l a r g e masonary t a n k w a s used t o measure t h e d i s c h a r g e of one type o f s l u i c e under a l l c o n d i t i o n s of h e a d and s l u i c e o p e n i n g . The r e s u l t s were t h e n a p p l i e d t o f l o w from o t h e r sluices. The S u d a n b r a n c h o f t h e E g y p t i a n I r r i g a t i o n S e r v i c e w a s formed i n 1 9 0 5 w i t h t h e O b j e c t o f p e r fo r m in g a l l h y d r o l o g i c and h y d r o g r a p h i c works f o r t h e d i f f e r e n t p r o j e c t s a i m i n g a t t h e i m p r o v e m e n t o f t h e w a t e r s u p p l y o f E g y p t and t h e d e v e l o p m e n t o f p e r e n n i a l i r r i g a t i o n i n t h e S u d a n . The d a t a c o l l e c t e d i n t h e p e r i o d 1906 t o 1 9 1 3 w e r e u s e f u l i n t h e d e s i g n o f t h e J e b e l A u l i a dam on t h e White N i l e ,
a b o u t 4 5 km a b o v e t h e j u n c t i o n o f t h e W h i t e a n d t h e B l u e N i l e s ,
and Makwar dam o n t h e B l u e N i l e , some 360 km a b o v e t h e same j u n c t i o n . The f o u n d a t i o n s o f t h e p r e s e n t M e t e o r o l o g i c a l S e r v i c e o f E g y p t w e r e l a i d i n 1 9 0 0 . S i n c e t h e n many s t a t i o n s w e r e e s t a b l i s h e d and more o b s e r v a t i o n s were t a k e n . I n 1 9 1 5 a l l t h e work o f a p h y s i c a l n a t u r e d o n e by t h e S u r v e y D e p a r t m e n t , and t h e h y d r o l o g i c a l work d o n e by t h e I r r i g a t i o n D e p a r t m e n t , w e r e combined t o form t h e P h y s i c a l D e p a r t m e n t o f t h e M i n i s t r y o f P u b l i c W o r k s , E g y p t . The work o n t h e N i l e p r o j e c t s s t o p p e d d u r i n g t h e F i r s t World War (1914-1918), t h o u g h r o u t i n e o b s e r v a t i o n s w e r e c a r r i e d o n . From 1 9 1 2 up t o 1 9 2 3 , e s p e c i a l l y i n t h e post-war
p e r i o d , most o f t h e p r o g r e s s w a s d i r e c t e d a t e s t a b l i s h i n g p e r -
manent d i s c h a r g e s i t e s a t a number o f i m p o r t a n t s t a t i o n s w h e r e r e g u l a r o b s e r v a t i o n s h a d b e e n t a k e n . Advances i n m e a s u r i n g d e v i c e s and t e c h n i q u e s f o l l o w e d . D a t a c o l l e c t i o n and a n a l y s i s w e n t o n and t h a t w a s a g r e a t h e l p i n t h e d e s i g n a n d c o n s t r u c t i o n o f t h e Makwar dam, w h i c h w a s f i n a l l y b u i l t i n 1 9 2 5 on t h e
11
Blue N i l e f o r t h e b e n e f i t of t h e Sudan. I n 1923 t h e M i n i s t r y o f P u b l i c Works, E g y p t , s e n t a m i s s i o n t o t h e E q u a t o r i a l L a k e s w i t h t h e aim o f p r e p a r i n g a programme f o r i n v e s t i g a t i o n s i n c o n n e c t i o n w i t h t h e p o s s i b l e Upper N i l e p r o j e c t s . T h a t m i s s i o n was f o l l o w e d by o t h e r s i n 1 9 2 4 , 1 9 2 6 , 1930 and 1931 t o i n v e s t i g a t e t h e h y d r o l o g y o f t h e Lake P l a t e a u , Bahr e l Ghazal and t h e White N i l e b a s i n s . The E a s t A f r i c a n M e t e o r o l o g i c a l S e r v i c e , l a t e r D e p a r t m e n t , EAMD, was formed i n 1 9 2 7 . T h i s d e p a r t m e n t w a s p a r t l y f i n a n c e d by t h e E g y p t i a n Government.
It
o p e r a t e s o v e r a l l o f E a s t C e n t r a l A f r i c a and t h e d a t a i t c o l l e c t s are u n d o u b t e d l y v a l u a b l e f o r t h e h y d r o l o g y of t h e N i l e B a s i n . The o r i g i n a l N i l e w a t e r s a g r e e m e n t w a s l a i d down i n 1929 and h a d , f o r some
t i m e , b e e n t h e b a s i s o f t h e w a t e r a l l o c a t i o n b e t w e e n E g y p t and t h e S u d a n . The most i m p o r t a n t i t e m i n t h e a g r e e m e n t was
". . .
no works s h o u l d b e c o n s t r u c t e d
o r m e a s u r e s t a k e n , on t h e N i l e or i t s b r a n c h e s or on t h e l a k e s from which i t flows,
i n t h e S u d a n or i n t h e t e r r i t o r i e s u n d e r B r i t i s h a d m i n i s t r a t i o n , which
w o u l d a f f e c t t h e f l o w o f t h e r i v e r i n s u c h a way as t o c a u s e p r e j u d i c e t o t h e i n t e r e s t s of Egypt". To e n s u r e t h e c o n t i n u i t y o f d i s s e m i n a t i o n o f t h e k n o w l e d g e o n t h e h y d r o l o g y o f t h e N i l e B a s i n and t o p r e s e n t t h e e v e r - i n c r e a s i n g d a t a i n a s y s t e m a t i c way, f o r b o t h s c i e n t i f i c and p r a c t i c a l p u r p o s e s ,
i t w a s d e c i d e d t o i s s u e t h e volumes
a n d s u p p l e m e n t s o f "The N i l e B a s i n " s u c c e s s i v e l y . The b a s i c d a t a a b o u t t h e s e r e f e r e n c e s are as f o l l o w s :
Volume No.
Subject matter
Author ( s)
Year of pub1 i c a t i o n
I
General d e s c r i p t i o n of t h e b a s i n ; meteorology, topography of t h e White N i l e
H . E . H u r s t and P. P h i l i p s
11
D i s c h a r g e and s t a g e m e a s u r e m e n t s o f t h e N i l e and i t s t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 6 3 - 6 7 and 1968-72)
H.E. Hurst, P. P h i l i p s , Y .M. Simaika, R . B l a c k and N i l e Control S t a f f
from 1932 onward
Ten-day mean and m o n t h l y mean g a u g e r e a d i n g s o f t h e N i l e and its t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 6 3 - 6 7 and 1968-72)
H.E. Hurst, P. P h i l i p s , Y . M . Simaika, R . P . B l a c k and N i l e Control S t a f f
from 1932 onward
I11
1931
12
Subject matter
Volume No.
Year of publication
Author ( s )
IV
Ten-day mean and monthly mean d i s c h a r g e s o f t h e N i l e and i t s t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 63-67, 1968-72)
H . E . Hurst, P. P h i l i p s , Y . M . Simaika, R . P . B l a c k and N i l e Control Staff
V
The h y d r o l o g y of t h e Lake P l a t e a u and Bahr e l J e b e l
H . E . H u r s t and P. Philips
VI
Monthly and a n n u a l r a i n f a l l t o t a l s and number o f r a i n y days a t s t a t i o n s i n and n e a r t h e N i l e B a s i n f o r p e r i o d s : 1938-42, 43-47, 48-52, 53-57, 58-62, 63-67 and 1968-72 ( 7 s u p p l e ments)
H.E. R.P. Y.M. Nile
VI I
The f u t u r e c o n s e r v a t i o n of t h e Nile
H.E. Hurst, R.P. Black and Y . M . Simaika
1946
VIII
The h y d r o l o g y of t h e S o b a t and White N i l e and t h e t o p o g r a p h y of t h e B l u e N i l e and A t b a r a
H.E.
Hurst
1950
IX
The h y d r o l o g y o f t h e B l u e N i l e and A t b a r a and t h e Main N i l e t o Aswan w i t h some r e f e r e n c e t o projects
H.E. Hurst, R.P.. Black and Y . M . Simaika
1959
X
The m a j o r N i l e p r o j e c t s
H.E. Hurst, R.P. B l a c k and Y . M . Simaika
1966
from 1933 onward
1938
Hurst; Black, S i m a i k a and Control S t a f f .
from 1950 onward
The d a t a and i n f o r m a t i o n c o n t a i n e d i n t h e a b o v e - l i s t e d volumes o f t h e N i l e Basin, t o g e t h e r with those appearing i n t h e o t h e r papers of t h e Physical D e p a r t m e n t , l a t e r t h e N i l e C o n t r o l D e p a r t m e n t , have b e e n employed i n t h e d e s i g n and c o n s t r u c t i o n o f t h e major h y d r a u l i c works on t h e N i l e and i t s b r a n c h e s and t r i b u t a r i e s . Examples o f t h e s e a r e : t h e h e i g h t e n i n g of t h e o r i g i n a l Aswan dam i n 1912 and i n 1 9 3 7 , t h e J e b e l A u l i a dam on t h e White N i l e i n 1934, t h e Owen F a l l s dam a t t h e e x i t o f Lake V i c t o r i a i n 1 9 5 0 ,
...
etc.
The i d e a o f c o n s t r u c t i n g a h i g h dam a t Aswan l e d t o a n o t h e r agreement between Egypt and t h e Sudan i n 1959 f o r t h e f u l l u t i l i z a t i o n of t h e N i l e w a t e r s . I t i s w o r t h w h i l e m e n t i o n i n g h e r e t h a t t h e d e s i g n o f t h i s dam was b a s e d on t h e t h e o r y o f o v e r - y e a r s t o r a g e . The e a r l i e s t t h o u g h t o f t h i s t h e o r y goes back t o b e f o r e 1946 ( H u r s t e t a l , 1 9 4 6 ) . The development o f t h e t h e o r y marked t h e b i r t h o f modern h y d r o l o g y , e s p e c i a l l y t h e s t o c h a s t i c p a r t of i t ( M a n d e l b r o t and W a l l i s , 1 9 6 8 ) . The y e a r 1959 a l s o w i t n e s s e d t h e f i r s t a t t e m p t t o p l a n f o r t h e u l t i m a t e h y d r a u l i c development of t h e N i l e V a l l e y u s i n g an e l e c t r o n i c d i g i t a l computer
13
( M o r r i c e and A l l a n , 1 9 5 9 ) . Although t h e N i l e h a s been t h e b e s t - s t u d i e d
river i n
t h e w o r l d f o r a g e n e r a t i o n , t h e need f o r many more i n v e s t i g a t i o n s and r e s e a r c h work i s t h e r e . The c o m p l e t i o n of t h e f i r s t p h a s e of t h e R o s e i r e s dam on t h e B l u e N i l e , t h e Khashm e l - G i r b a dam on t h e A t b a r a and t h e High dam on t h e Main N i l e a t Aswan a r e h y d r o l o g i c h i g h l i g h t s i n t h e n i n e t e e n hundred and s i x t i e s . A
very i m p o r t a n t s t e p which began i n 1 9 6 7 , and h a s c o n t i n u e d f o r q u i t e some y e a r s , i s t h e c o l l a b o r a t i o n between Kenya, T a n z a n i a , Uganda, t h e Sudan and Egypt i n a h y d r o m e t e o r o l o g i c a l s u r v e y of t h e c a t c h m e n t s of Lakes V i c t o r i a , Kyoga and A l b e r t . T h i s p r o j e c t i n c l u d e d t h e u p g r a d i n g of some of t h e e x i s t i n g h y d r o m e t r i c a l s t a t i o n s and t h e e s t a b l i s h m e n t of new h y d r o m e t r i c a l s t a t i o n s and r i v e r d i s c h a r g e measurement s i t e s . A l l t h e s e s t a t i o n s have been equipped w i t h modern i n s t r u m e n t s . The r a i n f a l l - r u n o f f
r e l a t i o n s h i p s were s t u d i e d i n a
number of e x p e r i m e n t a l b a s i n s and t h e r e l e v a n t p a r a m e t e r s e s t i m a t e d (WMO, 1974). The e a r l y s i x t i e s and t h e l a t e s e v e n t i e s of t h i s c e n t u r y w i t n e s s e d an unu s u a l r i s e i n t h e s u r f a c e w a t e r l e v e l s o f t h e E q u a t o r i a l Lakes and of o t h e r A f r i c a n l a k e s a s w e l l . The l e v e l o f Lake V i c t o r i a r o s e by o v e r 2 . 5 m e t r e s between 1959 and 1964 ( K i t e , G . ,
1 9 8 1 ) . For t h e same p e r i o d , t h e r i s e r e a c h e d
3 . 3 metres f o r Lake A l b e r t , 2 . 6 f o r Lake Tanganyika and 1 . 5 m e t r e s f o r Lake Malawi. The s e c o n d s u b s t a n t i a l r i s e began i n 1978 and by mid 1979 r e a c h e d about 1 . 8 metres f o r Lake V i c t o r i a , 3 . 0 f o r Lake Malawi and 1 . 0 metre f o r Lake
T a n g a n y i k a . The c o n s i d e r a b l e r i s e i n t h e Lake V i c t o r i a w a t e r l e v e l i n 1964 l e d t o an e x c e s s i v e flow i n t h e N i l e t o s u c h an e x t e n t t h a t i t f l o o d e d some p a r t s of C a i r o a t t h a t t i m e . Two p r i n c i p a l p r o j e c t s have been t a k i n g p l a c e d u r i n g t h e l a s t few y e a r s and a r e p r o b a b l y w o r t h r e c o r d i n g h e r e . One i s t h e f i r s t p h a s e of t h e d i v e r s i o n scheme ( c a l l e d J o n g l e i c a n a l ) . The c a n a l c o n n e c t s t h e B a h r e l J e b e l a t Bor s t r a i g h t t o a b o u t Malakal on t h e White N i l e and conveys 20 m i l l i o n m 3 p e r day a t maximum. The a n n u a l volume o f w a t e r s a v e d by t h i s scheme i s 3 . 8 m i l l i a r d m 3 e s t i m a t e d a t Aswan. Half o f t h i s amount w i l l b e t a k e n by t h e Sudan and t h e o t h e r h a l f by Egypt ( E x e c u t i v e Organ f o r t h e Development P r o j e c t s i n J o n g l e i Area, 1 9 7 5 ) . The s e c o n d e v e n t , s i n c e 1 9 7 8 , is t h e j o i n t work o f t h e M i n i s t r y of I r r i g a t i o n , E g y p t , r e p r e s e n t e d by i t s o r g a n s ( m a i n l y t h e Master Water P l a n and t h e R e s e a r c h I n s t i t u t e f o r Water R e s o u r c e s Development), t h e U n i v e r s i t y o f C a i r o , E g y p t , and t h e M a s s a c h u s e t t e s I n s t i t u t e of Technology, U.S.A. i n t h e a n a l y s i s of t h e h y d r o l o g i c d a t a of t h e N i l e B a s i n . The r e s u l t s s o f a r o b t a i n e d a r e a v a i l a b l e i n a s e r i e s of t e c h n i c a l r e p o r t s . A d d i t i o n a l l y , once e v e r y two y e a r s , t h e y o r g a n i z e a s o r t of c o n f e r e n c e where problems r e l a t e d t o w a t e r r e s o u r c e s p l a n n i n g , management and development a r e d i s c u s s e d , t o g e t h e r w i t h the possible solutions.
14
L a s t b u t n o t l e a s t , b o t h Egypt and t h e Sudan a r e working j o i n t l y t o e s t a b l i s h a commission o f a l l c o u n t r i e s s h a r i n g t h e N i l e w a t e r s . The r o a d t o r e a l i z i n g t h i s s t e p i s , no d o u b t , rough and f u l l of d i f f i c u l t i e s . N e v e r t h e l e s s , such a s t e p i s , i n t h e a u t h o r ' s o p i n i o n , unavoidable i f t h e s e c o u n t r i e s a r e keen on h a v i n g a more e f f i c i e n t u t i l i z a t i o n of t h e w a t e r r e s o u r c e s i n t h e N i l e Basin. REFERENCES Bixwas, A . K . , 1966. The N i l e , i t s o r i g i n and r i s e . Water and Sewage Works, 1 1 3 : 283-292 B i s w a s , A . K . , 1970. H i s t o r y of h y d r o l o g y . North-Holland, Amsterdam, 336 p p . B l a s h f o r d - S n e l l , J . N . , 1970. Conquest of t h e Blue N i l e . Geogr. J o u r n . 1 3 6 : 42-51. Cheesman, R . E . , 1 9 3 6 . Lake Tana and t h e B l u e N i l e . Macmillan, London, 400 p p . E n c y c l o p a e d i a B r i t a n n i c a , 1 9 6 9 . N i l e , Vol. 1 6 : 516-523. E x e c u t i v e Organ f o r t h e Development P r o j e c t s i n J o n g l e i A r e a , 1975. J o n g l e i P r o j e c t ( P h a s e O n e ) . Tamaddon P . P r e s s , Khartoum, 99 p p . F r i s i n g e r , H . H . , 1959. E a r l y t h e o r i e s on t h e N i l e f l o o d s . Weather, V o l . 2 0 : 206-207. G h a l e b , K . O . , 1935. D i s c u s s i o n o f : F l o o d - s t a g e r e c o r d s of t h e R i v e r N i l e , by C . S . J a r v i s . T r a n s . ASCE, P a p e r No. 1944: 1063-1067 ( d i s c u s s i o n : 1063-1067). Hashem, A . and E l - S h e r b i n i , H . , 1961. The h y d r o l o g i c f e a t u r e s of t h e 1954 and 1958 f l o o d s ( i n A r a b i c ) . The Government P r i n t e r , C a i r o , 98 p p . H u r s t , H . E . and P h i l i p s , P . , 1931. The N i l e B a s i n , Vol. I , G e n e r a l d e s c r i p t i o n o f t h e b a s i n , m e t e o r o l o g y and topography of t h e White N i l e B a s i n . P h y s i c a l Department P a p e r 2 6 , Government P r e s s , C a i r o , 128 p p . H u r s t , H . E . , B l a c k , R . P . and S i m a i k a , Y . M . , 1 9 4 6 . The N i l e B a s i n , Vol. V I I , The f u t u r e c o n s e r v a t i o n o f t h e N i l e , P h y s i c a l Department P a p e r 5 1 , E a s t e r n P r e s s , C a i r o , 159 p p . H u r s t , H . E . , 1 9 5 2 . The N i l e , a g e n e r a l a c c o u n t of t h e r i v e r and t h e u t i l i z a t i o n o f i t s w a t e r s . C o n s t a b l e , London, 326 p p . K i t e , G . W . , 1981. Recent c h a n g e s i n t h e l e v e l of Lake V i c t o r i a . B u l l e t i n o f H y d r o l o g i c a l S c i e n c e s , No. 2 6 , 3: 233-243. M a n d e l b r o t , B . B . and W a l l i s , J . R . , 1968. Noah, J o s e p h , and O p e r a t i o n a l Hydrology. Water R e s o u r c e s R e s e a r c h , V o l . 4 , N o . 5 : 909-918. Moorehead, A , , 1 9 6 0 . The White N i l e . Hamish H a m i l t o n , London. 385 pp. M o o r e h e a d , . A . , 1 9 6 2 . The B l u e N i l e . Hamish H a m i l t o n , London. 308 p p . M o r r i c e , A . W . and A l l a n , W . M . , 1 9 5 9 . P l a n n i n g f o r t h e u l t i m a t e development o f t h e N i l e V a l l e y . P r o c . I n s t . C i v i l Eng. 1 4 , P a p e r 6372: 101-155. P i e r r e , B . , 1974. Le Roman du N i l . L i b r a r i e P l o n , P a r i s , 480 p p . Stamp, D . L . and Morgan, W . T . , 1972. A f r i c a : A s t u d y i n t r o p i c a l d e v e l o p m e n t . J o h n Wiley and S o n s , I n c . , N e w York, 520 p p . T e c l a f f , L . A . and T e c l a f f , E . , 1973. A h i s t o r y of w a t e r development and w a t e r q u a l i t y . I n : Environment Q u a l i t y and Water Development ( E d i t o r s : Goldman, C . R . , McEvoy 111, J . and R i c h e r s o n , P . M . ) . W . H . Freeman and Company, San F r a n c i s c o : 26-77. World M e t e o r o l o g i c a l O r g a n i z a t i o n , 1974. H y d r o m e t e o r o l o g i c a l s u r v e y of t h e c a t c h m e n t s o f Lakes V i c t o r i a , Kyoga and A l b e r t , RAF 66-025, Tech. R e p o r t 1, Vols I , 1 1 , I 1 1 and IV. Y e v j e v i c h , V . , 1 9 8 3 . The N i l e R i v e r B a s i n : h a r d c o r e and s o f t c o r e w a t e r p r o j e c t s . Water I n t e r n a t i o n a l V o l . 8 , N o . 1: 23-34
Chapter 1
HISTORICAL INTRODUCTION
1.1
SOURCE OF THE NILE
The known h i s t o r y o f t h e N i l e R i v e r d a t e s b a c k t o j u s t b e f o r e 5000 B . C . From t h e n t i l l r e c e n t l y v a r i o u s t h e o r i e s a b o u t t h e s o u r c e o f t h e N i l e and i t s
r i s e h a v e b e e n l a i d down. Some of t h e s e t h e o r i e s were s o c o n f l i c t i n g t h a t i t became c u s t o m a r y i n a n c i e n t Rome t o s a y : q u a e r e r e f o n t e s N i l e ( s e a r c h for t h e N i l e ) when someone t a l k e d a b o u t a m y s t e r i o u s or i m p o s s i b l e matter ( P i e r r e , 1974). The name N i l e i s s a i d t o b e d e r i v e d f r o m t h e G r e e k N e i l o s , whose o r i g i n i s unknown. B o t h N e i l o s and A i g u p t o s ( m a s c u l i n e ) w e r e u s e d i n G r e e k drama when r e f e r r i n g t o t h e N i l e , w h e r e a s A i g u p t o s ( f e m i n i n e ) a l o n e was u s e d when r e f e r r i n g t o Egypt ( E n c y c lo p a e d ia B r i t a n n i c a ,
1969).
I t i s o f t e n c l a i m e d t h a t t h e a n c i e n t E g y p t i a n s knew n o t h i n g o f t h e o r i g i n of t h e i r r i v e r . T h i s c l a i m i s s u p p o r t e d o n o n e h a n d by t h e n a i v e c o n v i c t i o n o f t h e common a n c i e n t E g y p t i a n t h a t t h e N i l e f l o w s o u t o f t h e f u l l b r e a s t s o f t h e N i l e God, H a p i . The p r i e s t s o f a n c i e n t E g y p t , o n t h e o t h e r h a n d , h a d t h e i r own t h e o r y , w h i c h t h e y f a i t h f u l l y f o u n d e d o n t h e o l o g i c a l g r o u n d s . T h o s e p r i e s t s were c o n v i n c e d t h a t somewhere t h e c o u r s e o f "The C e l e s t i a l N i l e " w a s b e s e t by m o n s t r o u s r o c k s and s t o n e s and t h a t b e l o w t h i s b a r r i e r rose E g y p t ' s N i l e or E g y p t ' s h e a v e n - d e s c e n d e d s t r e a m . A f t e r a l l , t h e N i l e p r i e s t s were one of t h e s o u r c e s t h a t provided Herodotus, t h e I o n i a n , w i t h m o s t o f t h e informat i o n t h a t a p p e a r e d i n h i s w r i t t e n a c c o u n t s on Egypt and t h e N i l e . The p h i l o s o p h e r s and s a v a n t s o f a n c i e n t Greece h a d t h e i r v i e w s o n , and o p i n i o n s o f , t h e s o u r c e o f t h e N i l e and o f i t s r h y t h m i c p a t t e r n o f f l o w . T h e s e views comprised t h e r o l e o f t h e E t e s i a n ( n o r t h e r l y ) winds i n t h e bui l d-up o f the N i l e ,
t h e o r i g i n o f t h e r i v e r from Oceanus ( t h e ocean s u r r o u n d i n g t h e
e a r t h ) , and t h e r i s e o f t h e N i l e f r o m t h e p e a k s o f t h e L y b i a n m o u n t a i n s and
i t s s u p p l y f r o m t h e m e l t e d snow t h e r e o n . H e r o d o t u s w r o t e i n h i s a c c o u n t s t h a t , d u r i n g h i s v i s i t t o Egypt i n 457 B . C . ,
one informant s a i d t h a t t h e Nile r o s e
from a p o w e r f u l s p r i n g f e e d i n g a d e e p l a k e s i t u a t e d b e t w e e n t h e h i l l s o f Mophi and C h r o p h i . T h e r e a r e two t r a i n s o f t h o u g h t :
t h e f i r s t is t h a t t h e
s a i d l a k e l i e s b e t w e e n t h e i s l a n d o f E l e p h a n t i n e and Aswan, w h i c h c o n f i n e s t h e w h o l e s t o r y t o t h e N i l e i n E g y p t , and t h e o t h e r i s t h a t t h e l a k e i s s i t u a t e d f a r more t o t h e s o u t h . I n c o m p a r i s o n w i t h r e c e n t d i s c o v e r i e s t h e l a t t e r i s s o m e t i m e s i n t e r p r e t e d as t h e l a k e s u p p l y i n g t h e S e m l i k i R i v e r which d i s c h a r g e s
i t s w a t e r i n t o Lake A l b e r t ( a l s o c a l l e d Mobutu-Sese S e k o ) . I f w e a r e prepared t o accept t h i s i n t e r p r e t a t i o n ,
i t is then f a i r t o conclude t h a t
Herodotus c a n b e complimented f o r t h r o w i n g some l i g h t on t h e w e s t e r n t r i b u t a r y o f t h e N i l e R i v e r . I n a p a p e r e n t i t l e d "The N i l e , i t s O r i g i n and R i s e "
it is
mentioned t h a t H e r o d o t u s b e l i e v e d t h a t t h e Upper N i l e flowed from w e s t t o e a s t , b u t h e c o n f u s e d t h e Niger w i t h t h e N i l e ( B i s w a s , A . , f o r q u i t e some t i m e . J u b a I 1 (20 A . D . ) ,
1966). T h i s i d e a p r e v a i l e d
t h e King o f M a u r i t a n i a , a f f i r m e d t h a t
t h e s o u r c e of t h e N i l e was i n w e s t e r n A f r i c a , t h e r e b y s u p p o r t i n g t h e c o n v i c t i o n t h a t t h e N i g e r i s a b r a n c h of t h e N i l e ( B i s w a s , A , , The Greek p h i l o s o p h e r A r i s t o t l e (384-322 B . C . )
1966, 1970).
thought t h a t t he r i v e r
descended from a mountain of s i l v e r (montagne d ' a r g e n t ) and t h a t heavy s p r i n g and summer r a i n s on t h e h i g h l a n d s of t h e catchment a r e a s (what we c a l l nowadays t h e B l u e and White N i l e s ) were r e s p o n s i b l e f o r t h e flow i n t h e N i l e . Almost two c e n t u r i e s a f t e r H e r o d o t u s , came t h e m a t h e m a t i c i a n and g e o g r a p h e r E r a t o s t h e n e s (276-194 B . C . ) who d e s c r i b e d t h e N i l e f a r b e t t e r t h a n any of h i s p r e d e c e s s o r s . H i s i d e a w a s t h a t two p r i n c i p a l streams s p r a n g o u t o f some l a k e s s i t u a t e d t o t h e e a s t and e n c i r c l e d Meroe, a c o n s i d e r a b l y l a r g e i s l a n d ( s e e map, F i g . 1 . 1 . ) . The e a s t e r n t r i b u t a r y was t h e A s t a b o r a s (now c a l l e d t h e A t b a r a ) and t h e w e s t e r n t h e A s t a s o b a s (now c a l l e d t h e B l u e N i l e ) . The Astapus
(now c a l l e d
t h e White N i l e ) was a d i f f e r e n t r i v e r e n t i r e l y , which r o s e from some l a k e s t o t h e s o u t h and c a r r i e d t h e summer r a i n s t o form t h e d i r e c t stream of t h e N i l e . P t o l e m y , t h e Roman, who l i v e d i n A l e x a n d r i a i n t h e s e c o n d c e n t u r y A . D . , t h o u g h t t h a t t h e main N i l e came from t h e Mountains of t h e Moon, which w e r e p e r m a n e n t l y c o v e r e d w i t h snow and p a s s e d t h r o u g h two l a k e s . I t i s p r o b a b l e t h a t h e meant by t h e Mountains of t h e Moon, t h e Ruwenzori r a n g e and by t h e two l a k e s , V i c t o r i a and A l b e r t Nyanza. The map of t h e N i l e a s d e v e l o p e d by Ptolemy
i s a s shown i n F i g . 1.2. From t h e s e c o n d h a l f o f t h e s e c o n d c e n t u r y o n w a r d s , f o r a t l e a s t t h i r t e e n c e n t u r i e s , t h e r e w e r e h a r d l y any d i s c o v e r i e s , w i t h t h e e x c e p t i o n of some d e s c r i p t i o n s o f t h e lower r e a c h e s o f t h e N i l e by t h e mosl m g e o g r a p h e r s i n E g y p t . Examples a r e Al-Khuwarazmi
i n 864 A . D .
and Al-Masoudy
n 957 A . D .
The t r i u m p h a n t wars of P o r t u g a l a g a i n s t t h e Moors i n n o r t h - w e s t
Africa i n
t h e f i f t e e n t h c e n t u r y h a d , no d o u b t , paved t h e r o a d t o t h e P o r t u g u e s e i n f i l t r a t i o n i n A f r i c a , b o t h e a s t and w e s t . Two P o r t u g u e s e m i s s i o n a r i e s , P e d r o Paez and Jerome Lobo, v i s i t e d E t h i o p i a i n t h e s e v e n t e e n t h c e n t u r y . F a t h e r Paez v i s i t e d Lake Tana ( 1 6 1 8 ) . H i s s u c c e s s o r , F a t h e r Lob0 w r o t e an a c c o u n t a b o u t h i s v i s i t t o T i s s i s a t F a l l s . About 150 y e a r s l a t e r , i n 1770 A . D . ,
a Scottish
e x p l o r e r named James B r u c e , a f t e r h a v i n g j o u r n i e d f i v e y e a r s i n E t h i o p i a , s u c c e e d e d i n d i s c o v e r i n g t h e s o u r c e of t h e l i t t l e Abbai ( s e e map, F i g . 1 . 1 . ) . A summary of B r u c e ' s views on Paez and Cheesman's on t h e e x p e d i t i o n of Bruce
c a n be found i n t h e Book on The B l u e N i l e (Moorehead, A , ,
1962).
3
F i g . 1.1. L o c a t i o n o f t h e o l d i s l a n d o f Mero and t r i b u t a r i e s
The j o u r n e y s made by t h e Arab t r a d e r s on t h e e a s t c o a s t o f A f r i c a t o t h e i n t e r i o r , t h e r e l i g i o u s m i s s i o n s t o E a s t A f r i c a and t h e s t e a d i l y growing conn e c t i o n s between t h e C o p t i c c h u r c h e s o f A l e x a n d r i a and E t h i o p i a have a l l l e d t o more c o n c r e t e i n f o r m a t i o n on t h e snow-capped m o u n t a i n s ( t h e Mountains of t h e Moon) d e s c r i b e d by Ptolemy i n 150 A . D . The h i s t o r y o f e x p l o r i n g t h e N i l e r i v e r s y s t e m i n t h e n i n e t e e n t h c e n t u r y b e g i n s w i t h t h e i n v a s i o n of t h e Sudan by Mohammed A l i Pasha and h i s s o n s from 1821 onwards. A s a r e s u l t of t h i s , t h e B l u e N i l e was e x p l o r e d a s f a r a s i t s
e x i t from t h e E t h i o p i a n f o o t h i l l s , and t h e White N i l e a s f a r a s t h e S o b a t mouth. The Bahr e l Ghazal w a s e x p l o r e d by P e t h e r i c k i n t h e e i g h t e e n f i f t i e s . The c o n s i d e r a b l e i n t e r e s t o f t h e Europeans came s h o r t l y a f t e r t h e r e p o r t s o f Knoblecher (1850) a b o u t t h e e x i s t e n c e of some l a r g e l a k e s i n t h e s o u t h .
4
The M o u n t a i n s of the Moon
)
Second Lake
\
F i r s t Lake
) T h e holy Sprinq
v&&Donkola "
Aswan
Upper Land
"
K?
I
t
" M i d d i e Land
"
Asiut
A l - Ashmunein
A l - Muqattam
Mediterranean
Sea
I
F i g . 1 . 2 . Map of t h e N i l e from t h e s o u r c e a t t h e Mountains of t h e Moon t o t h e mouth i n t h e M e d i t e r r a n e a n S e a , a s p r e p a r e d by Ptolemy
From a b o u t 1857 onwards for a b o u t 30 y e a r s , t h e E q u a t o r i a l Lakes P l a t e a u and s u r r o u n d i n g s w e r e t r a v e r s e d by s e v e r a l e x p l o r e r s ,
a l l s e a r c h i n g for t h e
s o u r c e of t h e r i v e r t h a t h a d p u z z l e d t h e whole w o r l d for s e v e r a l c e n t u r i e s . The p r i n c i p a l e x p l o r e r s and t h e i r e x p e d i t i o n s w e r e as f o l l o w s : i)
B u r t o n and Speke went from Bagamoyo t o Tabora t o U j i j i on Lake Tanganyika (1857-59). I n 1858 Speke a l o n e went on n o r t h w a r d s and d i s c o v e r e d Lake V i c t o r i a .
5
S p e k e and G r a n t s e t o f f on an e x p e d i t i o n (1860-63)
ii)
around Lake V i c t o r i a
and r e a c h e d Ripon F a l l s . They t h o u g h t t h a t t h e stream f l o w i n g o u t of t h i s l a k e was t h e s o u r c e o f t h e N i l e . i i i ) Samuel B a k e r , a f t e r e x p l o r i n g t h e A t b a r a , went on t o d i s c o v e r Lake A l b e r t (1862-64)
a s w e l l a s t h e A l b e r t N i l e and t h e u p p e r r e a c h of
Bahr e l J e b e l . L i v i n g s t o n e , l i k e B u r t o n and S p e k e , s e t o f f on h i s r o u t e from Tabora
iv)
to U j i j i
( 1 8 7 2 ) . H e t h o u g h t t h e Lake Nyasa m i g h t b e d r a i n i n g i n t o Lake
T a n g a n y i k a , which c o u l d t h e n b e l i n k e d w i t h t h e A l b e r t Lake and t h e N i l e . v)
S t a n l e y t r a v e l l e d up from t h e e a s t c o a s t and c i r c u m n a v i g a t e d Lake V i c t o r i a ( 1 8 7 2 ) . H i s a t t e m p t t o g e t t o Lake A l b e r t was n o t s u c c e s s f u l , though h e r e a c h e d as f a r a s t h e e s c a r p m e n t a b o u t Lake George. I n a l a t e r j o u r n e y ( 1 8 8 9 ) h e r e a c h e d t h e S e m l i k i and Lake Edward. The r o u t e s o f t h e s e l e a d i n g e x p l o r e r s a r e i n d i c a t e d o n t h e map, F i g . 1 . 3 .
(Stamp and Morgan, 1 9 7 2 ) . I n s p i t e o f a l l t h e e x p e d i t i o n s a l r e a d y m e n t i o n e d , a number of t r i b u t a r i e s o f t h e N i l e remained u n d i s c o v e r e d . E x p l o r a t i o n m i s s i o n s s t o p p e d i n t h e p e r i o d 1881 up t o 1898 a s a r e s u l t o f t h e r e b e l l i o n s o f t h e Mahdis i n t h e S u d a n . A h i s t o r i c a l a c c o u n t o f t h i s p e r i o d c a n b e found i n t h e book e n t i t l e d "The White Nile"
(Moorehead, A , ,
1 9 6 0 ) . A f t e r t h e r e o p e n i n g of t h e Sudan i n 1898 and a t
a b o u t t h e same t i m e t h e o p e n i n g up o f Kenya and T a n z a n i a ( f o r m e r l y c a l l e d T a n g a n y i k a ) and Uganda, i r r i g a t i o n s e r v i c e s and s u r v e y and g e o l o g i c a l d e p a r t ments were e s t a b l i s h e d i n t h e r e s p e c t i v e c o u n t r i e s . S i n c e t h e n t h e s e d e p a r t ments h a v e t a k e n o v e r t h e e x p l o r a t o r y work a s w e l l a s t h e c o l l e c t i o n of h y d r o l o g i c and o t h e r r e l e v a n t d a t a ( H u r s t , H . ,
1952).
A t a b o u t t h e end o f 1902 t h e I r r i g a t i o n Department o f Egypt s t a r t e d two e x p e d i t i o n s ; t h e one u n d e r M r C . E .
Dupuis t o v i s i t Lake Tana and t h e o t h e r
u n d e r S i r W . G a r s t i n t o v i s i t t h e Lakes V i c t o r i a and t h e t h e n A l b e r t and Edward. The e x p e d i t i o n s which f o l l o w e d w e r e s e n t t o c o l l e c t , or r e p o r t o n , h y d r o l o g i c a l d a t a needed f o r t h e N i l e p r o j e c t s ( H u r s t , H . E . ,
1 9 3 1 ) . Unfortun-
a t e l y , t h e M a c m i l l a n - J e s s e n e x p e d i t i o n s i n 1902 and 1905 f a i l e d i n e x p l o r i n g Lake Tana o r f i n d i n g t h e s o u r c e o f t h e B l u e N i l e . A f t e r t h i s t h e r e was a l o n g p e r i o d o f i n a c t i v i t y on t h e r i v e r u n t i l R . E .
Cheesman a r r i v e d i n 1925 i n
E t h i o p i a . F o r t h e n e x t e i g h t y e a r s Cheesman d e v o t e d h i m s e l f t o t h e e x p l o r a t i o n o f t h e g o r g e o f t h e B l u e N i l e and t o c i r c u m n a v i g a t e Lake Tana. T h i s accomplishment was t e r m i n a t e d by w r i t i n g an a c c o u n t on Lake Tana and t h e B l u e N i l e (Cheesman, R . ,
1936).
More r e c e n t e x p e d i t i o n s h a v e b e e n s e n t , e s p e c i a l l y by t h e E g y p t i a n Governm e n t , t o e x p l o r e more o f t h e t r i b u t a r i e s i n t h e c a t c h m e n t s of t h e E q u a t o r i a l L a k e s , t h e White N i l e and t h e S o b a t . However, i t was n o t u n t i l 1937 t h a t t h e
6
southernmost s o u r c e of t h e N i l e i n t h e headstreams of t h e Kagera, l a r g e s t trib u t a r y o f Lake V i c t o r i a , was l o c a t e d . F u r t h e r e x p l o r a t i o n o f t h e N i l e t r i b u t a -
r i e s i n t h e E t h i o p i a n P l a t e a u h a s b e e n f o r q u i t e some t i m e l e s s f o r t u n a t e t h a n t o o t h e r p a r t s o f t h e N i l e B a s i n . The g o r g e o f t h e B l u e N i l e ( G r e a t A b b a i ) was n o t f u l l y t r a v e r s e d u n t i l a B r i t i s h m i l i t a r y and s c i e n t i f i c e x p e d i t i o n c o n quered i t d u r i n g t h e f l o o d o f 1968 ( B l a s h f o r d - S n e l l , J . N . ,
- - -Burton - - -Speke +++++
N
8, Speke 1857-'59
1858
Speke & Grant 1860-'63
.. ....... -
----
1970).
Baker Stanley
1862-'64 1871-'72, 1874-'77 8, 1887 - '8 9 L i v i n g s t o n e 1872
b Bagamoyo Tabora r o u t e s ~ m ~ l afor r Speke & Grant a n d S t a n l e y
F i g . 1 . 3 . The r o u t e s o f some l e a d i n g e x p l o r e r s o f t h e N i l e S o u r c e ( S t a m p , L . D . and Morgan, W.T., 1 9 7 2 )
1.2 1.2.1
HISTORY O F HYDROLOGY OF THE NILE BASIN
From 3200 B . C . t o 1900 A . D .
W h e t h e r t h e a n c i e n t E g y p t i a n s knew t h e o r i g i n o f t h e i r r i v e r or n o t ,
( s e e 1.1) w h a t c a n n o t b e d e n i e d i s t h a t t h e y were d e e p l y k e e n t o o b s e r v e a l l a s t r o n o m i c a l phenomena and t e r r e s t r i a l e v e n t s a s s o c i a t e d w i t h , o r r e l a t e d t o , the N i l e floods,
7
One of t h e most a n c i e n t r e c o r d s i s a drawing of an i m p e r i a l macehead h e l d by t h e p r o t o d y n a s t i c k i n g S c o r p i o n when c e l e b r a t i n g t h e o c c a s i o n of c u t t i n g an i r r i g a t i o n d i t c h some 3200 y e a r s B . C .
(Biswas, A . ,
1 9 7 0 ) . The same r e f e r -
e n c e m e n t i o n s , among o t h e r s : damming o f f of t h e N i l e and d i v e r t i n g i t s c o u r s e by King Menes i n 3000 B . C .
A t t h e same t i m e t h e a n c i e n t E g y p t i a n s began t o u s e
t h e N i l o m e t e r s t o r e c o r d t h e f l u c t u a t i o n of
t h e const r uct i on of
( P a g a n t s dam) some 30 k i l o m e t r e s s o u t h of C a i r o and i t s f a i l u r e
Sadd e l - K a f a r a i n 2850 B . C . ,
the N i l e ,
t h e c o n n e c t i o n o f t h e N i l e and t h e Red S e a by a n a v i g a t i o n a l
c a n a l d u r i n g t h e r e i g n of S e o s t r i s I i n a b o u t 1950 B . C . ,
t h e h y d r a u l i c works
of Amenemhet I 1 1 ( i n c l u d i n g Lake M o e r i s ) i n a b o u t 1850, t h e w a t e r codes of King Hammurabi i n 1750 B . C . , d e e p ) i n a b o u t 1700, e t c .
J o s e p h ' s w e l l n e a r C a i r o (more t h a n 100 metres
(Biswas, A , ,
1 9 7 0 ) . Another r e f e r e n c e s t a t e s t h a t
" h y d r a u l i c e n g i n e e r i n g " a t t h a t t i m e r e a c h e d a h i g h d e g r e e of accomplishment; r e c l a m a t i o n schemes on t h e l e f t bank of t h e N i l e were i n i t i a t e d d u r i n g t h e f l o o d s ; dams, d i k e s and c a n a l s w e r e c o n s t r u c t e d and l a t e r w a t e r - l i f t i n g machinery was i n v e n t e d ( T e c l a f f and T e c l a f f , 1 9 7 3 ) . Probably t h e f i r s t n o n - r e l i g i o u s
t h e o r y e x p l a i n i n g t h e y e a r l y f l o o d i n g was
t h a t d e r i v e d by t h e Greek T h a l e s (600 B . C . ) ,
t h e f o u n d e r of d e d u c t i v e geo-
m e t r y . H i s t h e o r y was t h a t t h e E t e s i a n winds d r o v e t h e s e a h i g h a g a i n s t t h e mouths of t h e r i v e r and t h e r e u p o n p r e v e n t e d them from d i s c h a r g i n g t h e i r w a t e r . The r i v e r t h e r e f o r e r e t u r n e d upon i t s e l f and, whenever i t c o u l d , i t b u r s t o u t i n t o f o r b i d d e n g r o u n d . A c o u p l e of c e n t u r i e s l a t e r a n o t h e r Greek g e o m e t e r , D e m o c r i t u s , came up w i t h a somewhat d i f f e r e n t t h e o r y . H e t h o u g h t t h a t when snow i n t h e n o r t h e r n p a r t s o f t h e w o r l d was m e l t e d a t t h e t i m e of t h e s u m m e r s o l s t i c e and flowed away, c l o u d s w e r e formed by t h e v a p o u r . When t h e c l o u d s
w e r e d r i v e n towards t h e s o u t h and towards Egypt by t h e E t e s i a n w i n d s , v i o l e n t s t o r m s a r o s e and c a u s e d t h e l a k e s f e e d i n g t h e R i v e r N i l e t o be f i l l e d (Frisinger, H . ,
1959).
S i n c e t h e N i l e u s e d t o r i s e i n f l o o d a t a b o u t t h e same t i m e e v e r y y e a r , i t s b e h a v i o u r had b e e n d e s c r i b e d a s r e g u l a r . The B i b l e t e l l s u s , however,
"
....
t h e r e came s e v e n y e a r s o f g r e a t p l e n t y t h r o u g h o u t t h e l a n d of E g y p t . And t h e r e s h a l l r i s e a f t e r them s e v e n y e a r s o f f a m i n e
.."
( G e n e s i s 4 1 , 29-30).
The i n t e r -
p r e t a t i o n by J o s e p h t o t h i s dream o f t h e P h a r a o of Egypt was p r o b a b l y t h e f i r s t indication of the persistence i n the hydrologic t i m e s e r i e s . The Roman s a v a n t , P l i n y (23-79 A . D . ) ,
t h o u g h t t h e two p r o b a b l e t h e o r i e s
a b o u t t h e f l o o d i n g of t h e N i l e w e r e t h o s e o f T h a l e s and Democritus.
After a l l ,
i n b o t h t h e o r i e s t h e a c t i o n of t h e E t e s i a n winds was t h e c u l p r i t . A f t e r P l i n y , t h e E n g l i s h h i s t o r i a n and t h e o l o g i a n , Beda (674-735 A . D . ) ,
compiled and sum-
m a r i z e d t h e knowledge t h e n a v a i l a b l e a b o u t t h e N i l e f l o o d . The t h e o r y h e p r o p o s e d was v e r y s i m i l a r t o t h a t of T h a l e s . H e c l a i m e d t h a t t h e n o r t h e r l y
8
winds f o r c e d t h e s e a waves t o p i l e up s a n d a t t h e N i l e mouths, t h u s c a u s i n g t h e r i v e r t o back up upon i t s e l f and f l o o d ( F r i s i n g e r , H . ,
1 9 5 9 ) . From t h a t
t i m e onwards u n t i l t h e n i n e t e e n t h c e n t u r y t h e r e was v e r y l i t t l e done t o e x p l o r e t h e s o u r c e s o f t h e N i l e and i t s t r i b u t a r i e s , e x c e p t f o r t h e r e c o r d i n g s which
w e r e done whenever p o s s i b l e . The n i n e t e e n t h c e n t u r y was t h e c e n t u r y of d i s c o v e r i n g t h e N i l e s o u r c e and t r i b u t a r i e s r a t h e r t h a n c o l l e c t i n g a n d / o r i n t e r preting its hydrologic data. The r e c o r d of t h e N i l e l e v e l s d a t e s back t o a b o u t 3000 t o 3500 y e a r s B . C . The r i v e r gauge is. c a l l e d N i l o m e t e r ( i n A r a b i c Miqyas An-Nil).
Three t y p e s of
N i l o m e t e r s were u s e d . The f i r s t t y p e c o n s i s t e d s i m p l y o f marking t h e w a t e r l e v e l s on c l i f f s on t h e banks of t h e r i v e r , e . g . t h e s e c o n d c a t a r a c t a t Semna. The s e c o n d t y p e c o n s i s t e d e s s e n t i a l l y of a s c a l e , u s u a l l y o f m a r b l e , on which t h e w a t e r l e v e l was o b s e r v e d . The s t a n d a r d gauge c o n s i s t e d o f a s e r i e s o f s t e p s
or p i l l a r s b u i l t i n t o t h e r i v e r bank t o e a c h of which a s e c t i o n of t h e s c a l e was f i x e d . I t i s c l a i m e d t h a t t h e r e a r e 140 o f t h e s e gauges s c a t t e r e d o v e r t h e b a s i n o u t s i d e E g y p t , and many more on t h e N i l e i n E g y p t . Most o f them a r e o b s e r v e d d a i l y , and t h e r e a d i n g s o f t h e more i m p o r t a n t a r e t e l e g r a p h e d or t e l e phoned t o C a i r o ( H u r s t , H . E . ,
1 9 5 2 ) . The c a t a s t r o p h i c f l o o d s o f 1954 and 1958
were measured a t 9 3 g a u g i n g p o i n t s i n Egypt o n l y , 36 gauges i n upper Egypt and t h e r e m a i n d e r i n l o w e r Egypt (Hashem and E l - S h e r b i n i ,
1 9 6 1 ) . The t h i r d and most
a c c u r a t e N i l o m e t e r used t o b r i n g w a t e r o f t h e N i l e t o a w e l l and t h e w a t e r l e v e l was marked e i t h e r on t h e w a l l s o f t h e w e l l or on a c e n t r a l p i l l a r . The most n o t a b l e N i l o m e t e r i s s i t u a t e d a t Roda n e a r C a i r o . The r e c o r d e d w a t e r l e v e l t h e r e d a t e s back t o 6 4 1 A . D . t h e r e i n 715 A . D .
The Arab c h a l i p h s (Kings) b u i l t a new N i l o m e t e r
T h i s was r e b u i l t i n 8 6 1 A . D .
I t c o n s i s t s of a squar e w e l l
c o n n e c t e d t o t h e N i l e by means o f t h r e e c o n d u i t s . A t t h e c e n t r e o f t h e w e l l i s a g r a d e d o c t a g o n a l p i l l a r of w h i t e m a r b l e d i v i d e d i n t o 19 c u b i t s (see F i g . 1 . 4 ) . I t was r e p o r t e d t h a t a s a r e s u l t o f p o o r j o i n i n g o f t h e lower b r o k e n p a r t o f t h e p i l l a r , t h e c o r r e s p o n d i n g c u b i t now measures 31 c m o n l y i n s t e a d o f t h e o r i g i n a l 54 c m ( G h a l e b , K., 1 9 3 5 ) . T h i s example and many o t h e r s shows t h a t t h e records a v a i l a b l e s i n c e 641 A . D .
need much a d j u s t m e n t b e f o r e h a v i n g them
a n a l y z e d . The s u i t a b i l i t y o f t h e r e c o r d f o r s t a t i s t i c a l a n a l y s i s h a s b e e n a r g u e d r e c e n t l y : "Simply,
t h e r e l i a b i l i t y of f l o o d d a t a f o r t h e assessment of
w a t e r a v e r a g e s , t h e r e l i a b i l i t y o f p r e s e r v a t i o n o f a l o n g - r a n g e c o n s t a n t gauge datum i n t h e p a s t , and a c c u r a c i e s i n o b s e r v a t i o n s ( a l l k i n d s o f c h a n g e s ) , unf o r t u n a t e l y do n o t p e r m i t one t o draw d e p e n d a b l e c o n c l u s i o n s " .
(Yevjecvich, V . ,
1983). 1.2.2
From 1900 A . D .
t i l l now
The t u r n of t h e l a s t c e n t u r y and t h e b e g i n n i n g o f t h e t w e n t i e t h c e n t u r y w i t n e s s e d a number of n o t a b l e a c c o m p l i s h m e n t s . When t h e t h e n Anglo-Egyptian
9
F i g . 1 . 4 . The N i l e gauge a t Roda, C a i r o , Egypt
10
S u d a n w a s r e o c c u p i e d i n 1 8 9 8 a l l swamp r i v e r s were f o u n d b l o c k e d u p . I t w a s n o t b e f o r e 1 9 0 5 t h a t a c h a n n e l t h r o u g h t h e B a h r e l J e b e l h a d b e e n made c l e a r . The G h a z a l was n o t made n a v i g a b l e t o t h e p r i n c i p a l c a p i t a l Wau, u n t i l 1 9 0 4 . I n 1 9 0 2 t h e w o r k s i n t h e f i r s t Aswan dam and some o f t h e B a r r a g e s o n t h e N i l e i n E g y p t were c o m p l e t e d . The h i s t o r y o f s c i e n t i f i c s t u d y o f t h e h y d r o l o g y
o f t h e N i l e b e g i n s w i t h t h e i n t r o d u c t i o n o f c u r r e n t metres by S i r H . Lyons i n about 1902. Previous t o t h i s ,
f l o w m e a s u r e m e n t s h a d b e e n made by f l o a t s . The
S u r v e y D e p a r t m e n t o f E g y p t became c h a r g e d w i t h t h e s u r v e y o f a l l r i v e r g a u g e r e c o r d s s o u t h o f Aswan i n 1 9 0 2 and 1 9 0 3 . T h i s w a s t h e o r i g i n o f t h e H y d r o l o g y S e r v i c e w h i c h formed p a r t o f t h e l a t e r P h y s i c a l D e p a r t m e n t o f E g y p t ( H u r s t and P h i l i p s , 1931) . The r e s u l t s o f t h e e x p e d i t i o n s t o L a k e s T a n a , V i c t o r i a , A l b e r t and Edward c o n d u c t e d by D u p u i s and G a r s t i n i n 1901-1904
( s e e 1 . 1 ) were c o n c l u d e d i n t h e
1904 r e p o r t by S i r W. G a r s t i n . S h o r t l y a f t e r t h a t , i n 1 9 0 6 , S i r H . Lyons publ i s h e d h i s book "The P h y s i o g r a p h y o f t h e N i l e " .
T h i s book c o n t a i n e d t h e i n f o r -
m a t i o n g a t h e r e d f r o m t r a v e l l e r s and s c i e n t i f i c e x p l o r e r s a v a i l a b l e a t t h a t
time.
I n 1905 S i r M .
MacDonald i n t r o d u c e d a new method o f r i v e r m e a s u r e m e n t a t
Aswan u s i n g t h e f l o w t h r o u g h t h e s l u i c e s o f t h e dam. A l a r g e masonary t a n k w a s used t o measure t h e d i s c h a r g e of one type o f s l u i c e under a l l c o n d i t i o n s of h e a d and s l u i c e o p e n i n g . The r e s u l t s were t h e n a p p l i e d t o f l o w from o t h e r sluices. The S u d a n b r a n c h o f t h e E g y p t i a n I r r i g a t i o n S e r v i c e w a s formed i n 1 9 0 5 w i t h t h e O b j e c t o f p e r fo r m in g a l l h y d r o l o g i c and h y d r o g r a p h i c works f o r t h e d i f f e r e n t p r o j e c t s a i m i n g a t t h e i m p r o v e m e n t o f t h e w a t e r s u p p l y o f E g y p t and t h e d e v e l o p m e n t o f p e r e n n i a l i r r i g a t i o n i n t h e S u d a n . The d a t a c o l l e c t e d i n t h e p e r i o d 1906 t o 1 9 1 3 w e r e u s e f u l i n t h e d e s i g n o f t h e J e b e l A u l i a dam on t h e White N i l e ,
a b o u t 4 5 km a b o v e t h e j u n c t i o n o f t h e W h i t e a n d t h e B l u e N i l e s ,
and Makwar dam o n t h e B l u e N i l e , some 360 km a b o v e t h e same j u n c t i o n . The f o u n d a t i o n s o f t h e p r e s e n t M e t e o r o l o g i c a l S e r v i c e o f E g y p t w e r e l a i d i n 1 9 0 0 . S i n c e t h e n many s t a t i o n s w e r e e s t a b l i s h e d and more o b s e r v a t i o n s were t a k e n . I n 1 9 1 5 a l l t h e work o f a p h y s i c a l n a t u r e d o n e by t h e S u r v e y D e p a r t m e n t , and t h e h y d r o l o g i c a l work d o n e by t h e I r r i g a t i o n D e p a r t m e n t , w e r e combined t o form t h e P h y s i c a l D e p a r t m e n t o f t h e M i n i s t r y o f P u b l i c W o r k s , E g y p t . The work o n t h e N i l e p r o j e c t s s t o p p e d d u r i n g t h e F i r s t World War (1914-1918), t h o u g h r o u t i n e o b s e r v a t i o n s w e r e c a r r i e d o n . From 1 9 1 2 up t o 1 9 2 3 , e s p e c i a l l y i n t h e post-war
p e r i o d , most o f t h e p r o g r e s s w a s d i r e c t e d a t e s t a b l i s h i n g p e r -
manent d i s c h a r g e s i t e s a t a number o f i m p o r t a n t s t a t i o n s w h e r e r e g u l a r o b s e r v a t i o n s h a d b e e n t a k e n . Advances i n m e a s u r i n g d e v i c e s and t e c h n i q u e s f o l l o w e d . D a t a c o l l e c t i o n and a n a l y s i s w e n t o n and t h a t w a s a g r e a t h e l p i n t h e d e s i g n a n d c o n s t r u c t i o n o f t h e Makwar dam, w h i c h w a s f i n a l l y b u i l t i n 1 9 2 5 on t h e
11
Blue N i l e f o r t h e b e n e f i t of t h e Sudan. I n 1923 t h e M i n i s t r y o f P u b l i c Works, E g y p t , s e n t a m i s s i o n t o t h e E q u a t o r i a l L a k e s w i t h t h e aim o f p r e p a r i n g a programme f o r i n v e s t i g a t i o n s i n c o n n e c t i o n w i t h t h e p o s s i b l e Upper N i l e p r o j e c t s . T h a t m i s s i o n was f o l l o w e d by o t h e r s i n 1 9 2 4 , 1 9 2 6 , 1930 and 1931 t o i n v e s t i g a t e t h e h y d r o l o g y o f t h e Lake P l a t e a u , Bahr e l Ghazal and t h e White N i l e b a s i n s . The E a s t A f r i c a n M e t e o r o l o g i c a l S e r v i c e , l a t e r D e p a r t m e n t , EAMD, was formed i n 1 9 2 7 . T h i s d e p a r t m e n t w a s p a r t l y f i n a n c e d by t h e E g y p t i a n Government.
It
o p e r a t e s o v e r a l l o f E a s t C e n t r a l A f r i c a and t h e d a t a i t c o l l e c t s are u n d o u b t e d l y v a l u a b l e f o r t h e h y d r o l o g y of t h e N i l e B a s i n . The o r i g i n a l N i l e w a t e r s a g r e e m e n t w a s l a i d down i n 1929 and h a d , f o r some
t i m e , b e e n t h e b a s i s o f t h e w a t e r a l l o c a t i o n b e t w e e n E g y p t and t h e S u d a n . The most i m p o r t a n t i t e m i n t h e a g r e e m e n t was
". . .
no works s h o u l d b e c o n s t r u c t e d
o r m e a s u r e s t a k e n , on t h e N i l e or i t s b r a n c h e s or on t h e l a k e s from which i t flows,
i n t h e S u d a n or i n t h e t e r r i t o r i e s u n d e r B r i t i s h a d m i n i s t r a t i o n , which
w o u l d a f f e c t t h e f l o w o f t h e r i v e r i n s u c h a way as t o c a u s e p r e j u d i c e t o t h e i n t e r e s t s of Egypt". To e n s u r e t h e c o n t i n u i t y o f d i s s e m i n a t i o n o f t h e k n o w l e d g e o n t h e h y d r o l o g y o f t h e N i l e B a s i n and t o p r e s e n t t h e e v e r - i n c r e a s i n g d a t a i n a s y s t e m a t i c way, f o r b o t h s c i e n t i f i c and p r a c t i c a l p u r p o s e s ,
i t w a s d e c i d e d t o i s s u e t h e volumes
a n d s u p p l e m e n t s o f "The N i l e B a s i n " s u c c e s s i v e l y . The b a s i c d a t a a b o u t t h e s e r e f e r e n c e s are as f o l l o w s :
Volume No.
Subject matter
Author ( s)
Year of pub1 i c a t i o n
I
General d e s c r i p t i o n of t h e b a s i n ; meteorology, topography of t h e White N i l e
H . E . H u r s t and P. P h i l i p s
11
D i s c h a r g e and s t a g e m e a s u r e m e n t s o f t h e N i l e and i t s t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 6 3 - 6 7 and 1968-72)
H.E. Hurst, P. P h i l i p s , Y .M. Simaika, R . B l a c k and N i l e Control S t a f f
from 1932 onward
Ten-day mean and m o n t h l y mean g a u g e r e a d i n g s o f t h e N i l e and its t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 6 3 - 6 7 and 1968-72)
H.E. Hurst, P. P h i l i p s , Y . M . Simaika, R . P . B l a c k and N i l e Control S t a f f
from 1932 onward
I11
1931
12
Subject matter
Volume No.
Year of publication
Author ( s )
IV
Ten-day mean and monthly mean d i s c h a r g e s o f t h e N i l e and i t s t r i b u t a r i e s (with 9 supplements: 1928-32, 33-37, 38-42, 43-47, 48-52, 53-57, 58-62, 63-67, 1968-72)
H . E . Hurst, P. P h i l i p s , Y . M . Simaika, R . P . B l a c k and N i l e Control Staff
V
The h y d r o l o g y of t h e Lake P l a t e a u and Bahr e l J e b e l
H . E . H u r s t and P. Philips
VI
Monthly and a n n u a l r a i n f a l l t o t a l s and number o f r a i n y days a t s t a t i o n s i n and n e a r t h e N i l e B a s i n f o r p e r i o d s : 1938-42, 43-47, 48-52, 53-57, 58-62, 63-67 and 1968-72 ( 7 s u p p l e ments)
H.E. R.P. Y.M. Nile
VI I
The f u t u r e c o n s e r v a t i o n of t h e Nile
H.E. Hurst, R.P. Black and Y . M . Simaika
1946
VIII
The h y d r o l o g y of t h e S o b a t and White N i l e and t h e t o p o g r a p h y of t h e B l u e N i l e and A t b a r a
H.E.
Hurst
1950
IX
The h y d r o l o g y o f t h e B l u e N i l e and A t b a r a and t h e Main N i l e t o Aswan w i t h some r e f e r e n c e t o projects
H.E. Hurst, R.P.. Black and Y . M . Simaika
1959
X
The m a j o r N i l e p r o j e c t s
H.E. Hurst, R.P. B l a c k and Y . M . Simaika
1966
from 1933 onward
1938
Hurst; Black, S i m a i k a and Control S t a f f .
from 1950 onward
The d a t a and i n f o r m a t i o n c o n t a i n e d i n t h e a b o v e - l i s t e d volumes o f t h e N i l e Basin, t o g e t h e r with those appearing i n t h e o t h e r papers of t h e Physical D e p a r t m e n t , l a t e r t h e N i l e C o n t r o l D e p a r t m e n t , have b e e n employed i n t h e d e s i g n and c o n s t r u c t i o n o f t h e major h y d r a u l i c works on t h e N i l e and i t s b r a n c h e s and t r i b u t a r i e s . Examples o f t h e s e a r e : t h e h e i g h t e n i n g of t h e o r i g i n a l Aswan dam i n 1912 and i n 1 9 3 7 , t h e J e b e l A u l i a dam on t h e White N i l e i n 1934, t h e Owen F a l l s dam a t t h e e x i t o f Lake V i c t o r i a i n 1 9 5 0 ,
...
etc.
The i d e a o f c o n s t r u c t i n g a h i g h dam a t Aswan l e d t o a n o t h e r agreement between Egypt and t h e Sudan i n 1959 f o r t h e f u l l u t i l i z a t i o n of t h e N i l e w a t e r s . I t i s w o r t h w h i l e m e n t i o n i n g h e r e t h a t t h e d e s i g n o f t h i s dam was b a s e d on t h e t h e o r y o f o v e r - y e a r s t o r a g e . The e a r l i e s t t h o u g h t o f t h i s t h e o r y goes back t o b e f o r e 1946 ( H u r s t e t a l , 1 9 4 6 ) . The development o f t h e t h e o r y marked t h e b i r t h o f modern h y d r o l o g y , e s p e c i a l l y t h e s t o c h a s t i c p a r t of i t ( M a n d e l b r o t and W a l l i s , 1 9 6 8 ) . The y e a r 1959 a l s o w i t n e s s e d t h e f i r s t a t t e m p t t o p l a n f o r t h e u l t i m a t e h y d r a u l i c development of t h e N i l e V a l l e y u s i n g an e l e c t r o n i c d i g i t a l computer
13
( M o r r i c e and A l l a n , 1 9 5 9 ) . Although t h e N i l e h a s been t h e b e s t - s t u d i e d
river i n
t h e w o r l d f o r a g e n e r a t i o n , t h e need f o r many more i n v e s t i g a t i o n s and r e s e a r c h work i s t h e r e . The c o m p l e t i o n of t h e f i r s t p h a s e of t h e R o s e i r e s dam on t h e B l u e N i l e , t h e Khashm e l - G i r b a dam on t h e A t b a r a and t h e High dam on t h e Main N i l e a t Aswan a r e h y d r o l o g i c h i g h l i g h t s i n t h e n i n e t e e n hundred and s i x t i e s . A
very i m p o r t a n t s t e p which began i n 1 9 6 7 , and h a s c o n t i n u e d f o r q u i t e some y e a r s , i s t h e c o l l a b o r a t i o n between Kenya, T a n z a n i a , Uganda, t h e Sudan and Egypt i n a h y d r o m e t e o r o l o g i c a l s u r v e y of t h e c a t c h m e n t s of Lakes V i c t o r i a , Kyoga and A l b e r t . T h i s p r o j e c t i n c l u d e d t h e u p g r a d i n g of some of t h e e x i s t i n g h y d r o m e t r i c a l s t a t i o n s and t h e e s t a b l i s h m e n t of new h y d r o m e t r i c a l s t a t i o n s and r i v e r d i s c h a r g e measurement s i t e s . A l l t h e s e s t a t i o n s have been equipped w i t h modern i n s t r u m e n t s . The r a i n f a l l - r u n o f f
r e l a t i o n s h i p s were s t u d i e d i n a
number of e x p e r i m e n t a l b a s i n s and t h e r e l e v a n t p a r a m e t e r s e s t i m a t e d (WMO, 1974). The e a r l y s i x t i e s and t h e l a t e s e v e n t i e s of t h i s c e n t u r y w i t n e s s e d an unu s u a l r i s e i n t h e s u r f a c e w a t e r l e v e l s o f t h e E q u a t o r i a l Lakes and of o t h e r A f r i c a n l a k e s a s w e l l . The l e v e l o f Lake V i c t o r i a r o s e by o v e r 2 . 5 m e t r e s between 1959 and 1964 ( K i t e , G . ,
1 9 8 1 ) . For t h e same p e r i o d , t h e r i s e r e a c h e d
3 . 3 metres f o r Lake A l b e r t , 2 . 6 f o r Lake Tanganyika and 1 . 5 m e t r e s f o r Lake Malawi. The s e c o n d s u b s t a n t i a l r i s e began i n 1978 and by mid 1979 r e a c h e d about 1 . 8 metres f o r Lake V i c t o r i a , 3 . 0 f o r Lake Malawi and 1 . 0 metre f o r Lake
T a n g a n y i k a . The c o n s i d e r a b l e r i s e i n t h e Lake V i c t o r i a w a t e r l e v e l i n 1964 l e d t o an e x c e s s i v e flow i n t h e N i l e t o s u c h an e x t e n t t h a t i t f l o o d e d some p a r t s of C a i r o a t t h a t t i m e . Two p r i n c i p a l p r o j e c t s have been t a k i n g p l a c e d u r i n g t h e l a s t few y e a r s and a r e p r o b a b l y w o r t h r e c o r d i n g h e r e . One i s t h e f i r s t p h a s e of t h e d i v e r s i o n scheme ( c a l l e d J o n g l e i c a n a l ) . The c a n a l c o n n e c t s t h e B a h r e l J e b e l a t Bor s t r a i g h t t o a b o u t Malakal on t h e White N i l e and conveys 20 m i l l i o n m 3 p e r day a t maximum. The a n n u a l volume o f w a t e r s a v e d by t h i s scheme i s 3 . 8 m i l l i a r d m 3 e s t i m a t e d a t Aswan. Half o f t h i s amount w i l l b e t a k e n by t h e Sudan and t h e o t h e r h a l f by Egypt ( E x e c u t i v e Organ f o r t h e Development P r o j e c t s i n J o n g l e i Area, 1 9 7 5 ) . The s e c o n d e v e n t , s i n c e 1 9 7 8 , is t h e j o i n t work o f t h e M i n i s t r y of I r r i g a t i o n , E g y p t , r e p r e s e n t e d by i t s o r g a n s ( m a i n l y t h e Master Water P l a n and t h e R e s e a r c h I n s t i t u t e f o r Water R e s o u r c e s Development), t h e U n i v e r s i t y o f C a i r o , E g y p t , and t h e M a s s a c h u s e t t e s I n s t i t u t e of Technology, U.S.A. i n t h e a n a l y s i s of t h e h y d r o l o g i c d a t a of t h e N i l e B a s i n . The r e s u l t s s o f a r o b t a i n e d a r e a v a i l a b l e i n a s e r i e s of t e c h n i c a l r e p o r t s . A d d i t i o n a l l y , once e v e r y two y e a r s , t h e y o r g a n i z e a s o r t of c o n f e r e n c e where problems r e l a t e d t o w a t e r r e s o u r c e s p l a n n i n g , management and development a r e d i s c u s s e d , t o g e t h e r w i t h the possible solutions.
14
L a s t b u t n o t l e a s t , b o t h Egypt and t h e Sudan a r e working j o i n t l y t o e s t a b l i s h a commission o f a l l c o u n t r i e s s h a r i n g t h e N i l e w a t e r s . The r o a d t o r e a l i z i n g t h i s s t e p i s , no d o u b t , rough and f u l l of d i f f i c u l t i e s . N e v e r t h e l e s s , such a s t e p i s , i n t h e a u t h o r ' s o p i n i o n , unavoidable i f t h e s e c o u n t r i e s a r e keen on h a v i n g a more e f f i c i e n t u t i l i z a t i o n of t h e w a t e r r e s o u r c e s i n t h e N i l e Basin. REFERENCES Bixwas, A . K . , 1966. The N i l e , i t s o r i g i n and r i s e . Water and Sewage Works, 1 1 3 : 283-292 B i s w a s , A . K . , 1970. H i s t o r y of h y d r o l o g y . North-Holland, Amsterdam, 336 p p . B l a s h f o r d - S n e l l , J . N . , 1970. Conquest of t h e Blue N i l e . Geogr. J o u r n . 1 3 6 : 42-51. Cheesman, R . E . , 1 9 3 6 . Lake Tana and t h e B l u e N i l e . Macmillan, London, 400 p p . E n c y c l o p a e d i a B r i t a n n i c a , 1 9 6 9 . N i l e , Vol. 1 6 : 516-523. E x e c u t i v e Organ f o r t h e Development P r o j e c t s i n J o n g l e i A r e a , 1975. J o n g l e i P r o j e c t ( P h a s e O n e ) . Tamaddon P . P r e s s , Khartoum, 99 p p . F r i s i n g e r , H . H . , 1959. E a r l y t h e o r i e s on t h e N i l e f l o o d s . Weather, V o l . 2 0 : 206-207. G h a l e b , K . O . , 1935. D i s c u s s i o n o f : F l o o d - s t a g e r e c o r d s of t h e R i v e r N i l e , by C . S . J a r v i s . T r a n s . ASCE, P a p e r No. 1944: 1063-1067 ( d i s c u s s i o n : 1063-1067). Hashem, A . and E l - S h e r b i n i , H . , 1961. The h y d r o l o g i c f e a t u r e s of t h e 1954 and 1958 f l o o d s ( i n A r a b i c ) . The Government P r i n t e r , C a i r o , 98 p p . H u r s t , H . E . and P h i l i p s , P . , 1931. The N i l e B a s i n , Vol. I , G e n e r a l d e s c r i p t i o n o f t h e b a s i n , m e t e o r o l o g y and topography of t h e White N i l e B a s i n . P h y s i c a l Department P a p e r 2 6 , Government P r e s s , C a i r o , 128 p p . H u r s t , H . E . , B l a c k , R . P . and S i m a i k a , Y . M . , 1 9 4 6 . The N i l e B a s i n , Vol. V I I , The f u t u r e c o n s e r v a t i o n o f t h e N i l e , P h y s i c a l Department P a p e r 5 1 , E a s t e r n P r e s s , C a i r o , 159 p p . H u r s t , H . E . , 1 9 5 2 . The N i l e , a g e n e r a l a c c o u n t of t h e r i v e r and t h e u t i l i z a t i o n o f i t s w a t e r s . C o n s t a b l e , London, 326 p p . K i t e , G . W . , 1981. Recent c h a n g e s i n t h e l e v e l of Lake V i c t o r i a . B u l l e t i n o f H y d r o l o g i c a l S c i e n c e s , No. 2 6 , 3: 233-243. M a n d e l b r o t , B . B . and W a l l i s , J . R . , 1968. Noah, J o s e p h , and O p e r a t i o n a l Hydrology. Water R e s o u r c e s R e s e a r c h , V o l . 4 , N o . 5 : 909-918. Moorehead, A , , 1 9 6 0 . The White N i l e . Hamish H a m i l t o n , London. 385 pp. M o o r e h e a d , . A . , 1 9 6 2 . The B l u e N i l e . Hamish H a m i l t o n , London. 308 p p . M o r r i c e , A . W . and A l l a n , W . M . , 1 9 5 9 . P l a n n i n g f o r t h e u l t i m a t e development o f t h e N i l e V a l l e y . P r o c . I n s t . C i v i l Eng. 1 4 , P a p e r 6372: 101-155. P i e r r e , B . , 1974. Le Roman du N i l . L i b r a r i e P l o n , P a r i s , 480 p p . Stamp, D . L . and Morgan, W . T . , 1972. A f r i c a : A s t u d y i n t r o p i c a l d e v e l o p m e n t . J o h n Wiley and S o n s , I n c . , N e w York, 520 p p . T e c l a f f , L . A . and T e c l a f f , E . , 1973. A h i s t o r y of w a t e r development and w a t e r q u a l i t y . I n : Environment Q u a l i t y and Water Development ( E d i t o r s : Goldman, C . R . , McEvoy 111, J . and R i c h e r s o n , P . M . ) . W . H . Freeman and Company, San F r a n c i s c o : 26-77. World M e t e o r o l o g i c a l O r g a n i z a t i o n , 1974. H y d r o m e t e o r o l o g i c a l s u r v e y of t h e c a t c h m e n t s o f Lakes V i c t o r i a , Kyoga and A l b e r t , RAF 66-025, Tech. R e p o r t 1, Vols I , 1 1 , I 1 1 and IV. Y e v j e v i c h , V . , 1 9 8 3 . The N i l e R i v e r B a s i n : h a r d c o r e and s o f t c o r e w a t e r p r o j e c t s . Water I n t e r n a t i o n a l V o l . 8 , N o . 1: 23-34