M O N I T O R I N G L A N D C O V E R C H A N G E S BY R E M O T E S E N S I N G IN N O R T H W E S T E G Y P T
S u b m i t t e d by
T i m o t h y S t e v e n R i c h a r d s
•for the d e g r e e of MPhi 1 at
Th e Scho o l D f O r i e n t a l and A f r i c a n S t u d i e s L o n d o n U n i v e r s i t y
1986
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A B S T R ACT
Th e M e d i t e r r a n e a n c o a s t a l s t r i p of E g y p t is a s e m i - a r i d
e n v i r o n m e n t w h i c h s u p p o r t s a v a r i e t y d+ a g r i c u l t u r a l p r a c t i c e s r a n g i n g f r o m i r r i g a t e d s e d e n t a r y a g r i c u l t u r e to s e m i - n o m a d i c p a s t o r a l ism. T h e s e d e n t a r i s a t ion of the n o m a d i c B e d o u i n c o u p l e d wit h an i n c r e a s e in p o p u l a t i o n of b o t h p e o p l e and l i v e s t o c k and a d e c r e a s e in th e e x t e n t of t he r a n g e l a n d s , ha s r e s u l t e d in s e v e r e p r e s s u r e b e i n g e x e r t e d upon the e n v i r o n m e n t . S a t e l l i t e r e m o t e s e n s i n g of v e g e t a t i o n o f f e r s the p o t e n t i a l to aid
r eg i o n a l m a n a g e m e n t by c o m p l e m e n t i n g c o n v e n t i o n a l t e c h n i q u e s of v e g e t a t i o n m a p p i n g and m o n i t o r i n g . T h i s t h e s i s e x a m i n e s the d i f f e r e n t t e c h n i q u e s a v a i l a b l e for v e g e t a t i o n m a p p i n g u s i n g v i s i b l e and near i nfra red s p e c t r a l w a v e bands.
Th e d i f f e r e n t t e c h n i q u e s a v a i l a b l e fo r v e g e t a t i o n m a p p i n g u s i n g r e m o t e l y s e n s e d d a t a a r e r e v i e w e d and d i s c u s s e d w i t h r e f e r e n c e to s e m i - a r i d e n v i r o n m e n t s . T h e u n d e r l y i n g s i m i l a r i t y of m a n y of the t e c h n i q u e s is e m p h a s i s e d and their i n d i v i d u a l m e r i t s
d i s c u s s e d . T h e s p e c t r a l f e a t u r e - s p a c e of L a n d s a t d a t a of two r e p r e s e n t a t i v e s t u d y a r e a s in n o r t h e r n E g y p t is e x p l o r e d and e x a m i n e d u s i n g g r a p h i c a l t e c h n i q u e s and p r i n c i p a l c o m p o n e n t s analysis.
Hand held r a d i o m e t r i c f i e l d d a t a ar e a l s o p r e s e n t e d f o r
in d i v i d u a l soil t y p e s w i t h i n the region. It is p r o p o s e d that by u s i n g r e f e r e n c e d a t a fo r in d i v i d u a l soil types, i m p r o v e d
e s t i m a t e s of v e g e t a t i o n c ov e r can be a s c e r t a i n e d .
i i
i
A n u m b e r of r a d i o m e t r i c c o r r e c t i o n s are a p p l i e d to t h e d i g i t a l L a n d s a t d a t a in o r d e r to c o n v e r t the a r b i t r a r y d i g i t a l v a l u e s of the d i f f e r e n t s p e c t r a l b a n d s into p hy s i c a l v a l u e s D f
r e f l e c t a n c e . T h e e f f e c t of t h i s s t a n d a r d i z a t i o n on the
p r i n c i p a l c o m p o n e n t s is e x a m i n e d . T h e s t r a t i f i e d a p p r o a c h to v e g e t a t i o n m a p p i n g w h i c h was e x p l o r e d u s i n g the f i e l d d a t a is
a p p l i e d in turn to t he d i g i t a l L a n d s a t images. W h i l s t the s t r a t i f i e d a p p r o a c h w a s not fo u n d to o f f e r s i g n i f i c a n t
a d v a n t a g e s o v e r t h e n o n - s t r a t i f i e d a p p r o a c h in t h i s case, t h e a n a l y s i s d o e s s e r v e to p r o v i d e an a c c u r a t e d a t u m a g a i n s t w h i c h to m e a s u r e v e g e t a t i o n .
In c o n c l u s i o n a s a t e l l i t e b a s e d s y s t e m far o p e r a t i o n a l v e g e t a t i o n m o n i t o r i n g is propo s e d .
a c k n o w l e d g m e n t s
P r i n c i p a l l y I w o u l d like to th a n k Dr T o n y A l l a n of S O A S for his su p port, e n c o u r a g e m e n t , and m o s t of all for his p a t i e n c e d u r i n g the c o u r s e of t h i s degree. I w o u l d 1' a l s o like to th a n k P r o f e s s o r Ay y a d and all of the m e m b e r s of his s taff in the B o t a n y
D e p a r t m e n t of A l e x a n d r i a U n i v e r s i t y , for th e help, f r i e n d s h i p and h o s p i t a l i t y w h i c h t h e y e x t e n d e d to m e d u r i n g my s t a y in Egypt. T h a n k s a re a l s o d u e to the C e n t r a l R e s e a r c h F u n d of L o n d o n U n i v e r s i t y w h i c h f i n a n c e d the f i e l d w o r k , and a l s o Br i s t o l U n i v e r s i t y w h i c h p r o v i d e d t ime and i mage p r o c e s s i n g f a c i l i t i e s for the c o m p l e t i o n of th e work. And l a s t l y I wo u l d like to t hank J oy m y w i f e for all of her s u p p o r t and s a c r i f i c e o v e r the p a s t f i v e years.
n't id
C O N T E N TS
1 I N T R O D U C T I O N
1.1 I n t r o d u c t i o n . ... 2
2 T H E S T U D Y A R E A
2. 1 L o c a t i o n and p h y s i o g r a p h y . ... . 7 2 . 2 C l i m a t e . . . ... . . . 1 2
2.3.1 I r r i g a t e d a g r i c u l t u r e . . ... IS
2 . 3 . 2 D r y l a n d agr i cu 1 tur e . . . ... 2 0
. 3 P a s t o r a l i sm. ... 23
S o i l s . . . .... 25
C o n c l u s i o n s . . . * . . . 28 3 R E N O T E S E N S I N G OF V E G E T A T I O N
3.1 R e m o t e s e n s i n g of v e g e t a t i o n - a l i t e r a t u r e r e v i e w ... 31 3 .2 T he v e g e t a t i o n i n d e x . . . ... 38 3 . 3 Mu 11 i t e m p o r a l c l a s s i f i c a t i o n . . . ... ..44 3.4 P r i n c i p a l c o m p o n e n t s a n a l y s i s ... . . . 4 7 3. 5 I n t e n s i t y , hue, s a t u r a t i o n c o l o u r c o d i n g . . . 50 3.6 A r i d e n v i r o n m e n t s - a s p e cial c a s e . . ... ...54
3. 7 S u m m a r y ... 56
4 I N I T I A L D I G I T A L P R O C E S S ING
4.1 A v a i l a b i l i t y of L a n d s a t i m a g e r y . . . ... 59 4 .2 A v a i l a b i l i t y of im a g e p r o c e s s i n g f a c i l i t i e s . . . . ... ...60 4 .3 T r a n s e c t 1 - the f a l s e c o l o u r c o m p o s i t e . . ... ..60 4 . 4 D i s t r i b u t i o n of th e d a t a w i t h i n L a n d s a t f e a t u r e - s p a c e .... 65 4. 5 T r a n s e c t 1 p r i n c i p a l c o m p o n e n t s a n a l y s i s . . . ...68 4 . 6 T r a n s e c t 3 - the f a l s e c o lo u r i m a g e ... ..77 4. 7 D i s t r i b u t i o n of th e d a t a w i t h i n L a n d s a t f e a t u r e - s p a c e . ... 83 4. 8 T r a n s e c t 3 p r i n c i p a l c o m p o n e n t s a n a l y s i s . ... .86 5 F I E L D W O R K
5. 1 I n t r o d u c t i o n . . . ... . . ....91
5 . 2 F i e l d rad i o m e t r y . . . ... 92
5. 3 A p p r o a c h and m e t h o d o l o g y . . ... 96 5. 4 G r a p h i c a l an s t a t i s t i c a l a n a l y s i s of the f i e l d d a t a 101 5 . 5 P r i n c i p a l c o m p o n e n t s a n a l y s i s of f i el d d a t a ... ...ill
5 . 6 C o n c l u s i o n s . ... 114
6 F U R T H ER D I G I T AL P R O C E S S I N G
6.1 The e f f e c t of f i e l d w o r k upon s u b s e q u e n t d i g i t a l
p r o c e s s i n g ... 117
6 .2 C o n v e r s i o n of L a n d s a t M S S d a t a into p h y s i c a l v a l u e s . .... 120
6 . 3 H a z e c o r r e c t i o n . ... 123
6 .4 T he e f f e c t s of c a l i b r a t i o n on band r a t i o s and
d i f f e r e n c e s , . ... 125
6.5 P r i n c i p a l c o m p o n e n t s a n a l y s i s of DN and r e f l e c t a n c e
i m a g e ... 129
6. 6 Two d i m e n s i o n a l soil line a n a l y s i s . . . 135
v
7 C O N C L U S I O N S AM D R E C O M M E N D A T IONS
7. 1 S u m m a r y ... 142
7. 2 C o n c l u s i o n s ... 143
7. 3 M a t c h i n g r e m o t e s e n s i n g t e c h n o l o g y to real n e e d s . ... 145
7.4 R e q u i r e m e n t s -for o p e r a t i o n a l m o n i t o r i n g . ... 151
7 . 5 An i n t e g r a t e d in-formation s y s t e m . . . ... 175
7. 6 A low c ost m o n i t o r i n g s y s t e m . . . . ... 156
B I B L I O G R A P H Y . ... 160
A P P E N D I X A F O R T R A N 77 p r o g r a m s . ... 170
v i
k i g I _ g E „ F l g y g g S ftNP I L L U S T R A T I O N S
1 I N T R O D U C T I O N
2 T HE S T U D Y A R EA
F i g u r e 2 . 1 . 1 - P h y s i o g r a p h i c c r o s s - s e c t i o n at El O m a y e d . . . . 10
T a b l e 2 . 1. 1 - T h e m a j o r p h y s i o g r a p h i c s y s t e m s at El O m a y e d ... 11
P l a t e 2 . 1 . 1 - A s o u t h e r l y v i e w at El O m a y e d t o w a r d s the i n l a n d pla t e a u . ... 13
F i g u r e 2 . 2 . 1 - M e a n a n n u a l r a i n f a l l at s e l e c t e d l o c a t i o n s a l o n g the coast. ... 13
F i g u r e 2 . 2 . 2 - S e a s o n a l r a i n f a l l at El D a b a ... 15
F i g u r e 2 . 2 . 3 - T h e r e l a t i o n s h i p b e t w e e n r a i n f a l l a n d d i s t a n c e f r o m the coast. ... 15
F i g u r e 2 . 2 . 4 - T h e s e a s o n a l w a t e r b a l a n c e . ... 17
P l a t e 2 . 3 . 2 - A s t o r a g e m o u n d u n d e r w h i c h s u r p l u s b a r l e y is s t o r e d . ... 17
P l a t e 2 . 3 . 1 - A p o r t i o n of a k a r m to the s o u t h of B u r g El Arab. ... 22
P l a t e 2 . 4 . 1 - G o a t s and c a m e l s g r a z i n g to th e s o u t h of B u r g el Arab. ... 27
3 R E M O T E S E N S I N G OF V E G E T A T IO N A L I T E R A T U R E R E V IEW F i g u r e 3 .1 . 1 - T h e ' T a s s e l l e d C a p ’ . 36 F i g u r e 3 .2 . 1 - L a n d s a t #7 v s #5 f e a t u e - s p a c e s u b d i v i d e d w i t h a # 7 / # 5 r a t i o ... . 36
F i g u r e 3 . 2 . 2 - T h e P e r p e n d i c u 1ar V e g e t a t i o n I n d e x . ... 40
F i g u r e 3 . 2 . 3 - Soil s p e c t r a in the m a i n soil b r i g h t n e s s - g r e e n n e s s plane. ... 40
F i g u r e 3 . 3 . 1 - T h e t e m p o r a l c h a n g e s in th e s p e c t r a l r e s p o n s e of w he a t f i e l d s . . . . ... 46
F i g u r e 3 . 5 . 1 a - T h e c o l o u r t r i a n g l e . . . ... 52
F i g u r e 3.5. lb- T h e c o l o u r c u b e ... 52
F i g u r e 3 . 5 . 1 c - T h e r e l a t i o n s h i p b e t w e e n hue a n d s a t u r a t i o n . 52 4 I N I T IAL D I G I T A L P R O C E S S I NG F i g u r e 4 . 1 . 1 - L a n d s a t and R E M D E N E t r a n s e c t l o c a t i o n m a p . . . 61
P l a t e 4 . 3 . 1 - T r a n s e c t 1 f a l s e c o l o u r c o m p o s i t e ... 63
F i g u r e 4 . 4 . 1 - T r a n s e c t 1 # 7 vs t*5 s c a t t e r p 1 o t . . ... 67
T a b l e 4 . 5 . 1 - T r a n s e c t 1 PC s t a t i s t i c s . . . ... 69
F i g u r e 4 . 5 . la- T r a n s e c t PCI vs P C 2 f e a t u r e - s p a c e ... 71
F i g u r e 4 . 5 . 1 b - T r a n s e c t PCI vs P C 2 f e a t u r e - s p a c e s u b d i v i d e d 71 T a b l e 4 . 5 . 2 - T r a n s e c t 1 PC c l a s s i f i c a t i o n k e y ... 73
P l a t e 4 . 5 . 1 - T r a n s e c t 1 PC c l a s s i f i c a t i o n . . ... 74
P l a t e 4 . 6 . 1 - T r a n s e c t 3 f a l s e c o l o u r c o m p o s i t e ... 79
F i g u r e 4 . 6 . 1 - P l a n v i e w of the U N E S C O B i o s p h e r e R e s e r v e . . . 81
P l a t e 4 . 6 . 2 - T h e U N E S C O B i o s p h e r R e s e r v e . . . ... 82
F i g u r e 4 . 7 . 1 - T r a n s e c t 3 # 7 vs # 5 s c a t t e r p l o t ... 85
T a b l e 4 . 8 . 1 - T r a n s e c t 3 PC s t a t i s t i c s ... 86
T a b l e 4 . 3 . 2 - T r a n s e c t 3 PC c 1a s s i f i c a t i o n k e y . . . 87
F i g u r e 4 . 8 . 1 a - T r a n s e c t 3 PCI vs P C 2 f e a t u r e - s p a c e ... 33
v i i
F i g u r e 4 . 8 . 1 b - T r a n s e c t 3 PCI vs P C 2 f e a t u r e - s p a c e
s u b d i v i d e d . ... 38
P l a t e 4 .3 . 1 - T r a n s e c t 3 PC c l a s s i f i c a t i o n . . . ... 89
5 F I E L D W O R K F i g u r e 5 . 2 . 1 - F i l t e r c h a r a c t e r i s t i c s of L a n d s a t M S S and M i l t o n f our b and r a d i om e t e r . . . ... 93
F i g u r e 5 . 3 . 1 - F i e l d s i t e l o c a t i o n m a p . . . ... 97
T a b l e 5 . 3 . 1 - F i e l d s it e soil t y p e s . . . ... 96
F i g u r e 5 . 3 . 2 - 1 983 h a n d h e l d r a d i o m e t e r s c a t t e r p 1o t s ... 100
F i g u r e 5 . 4 . 1 - 1 984 h a n d h e l d r a d i o m e t e r s c a t t e r p 1o t s ... 102
T a b l e 5 . 4 . 1 - D i s c r e t e soil line s t a t i s t i c s ... 104
F i g u r e 5 . 4 . 2 - 1 9 3 4 a n n o t a t e d r a d i o m e t e r s c a t t e r p l o t s ... 105
T a b l e 5 . 4 . 2 - D i s c r e t e soil line PVI values. . . 107
F i g u r e 5 . 4 . 3 - Soil li n e s d e r i v e d f r o m r a d i o m e t e r d a t a . . . . .1 1 0 F i g u r e 5 .5 . 1 - P C A of r a d i o m e t e r d a t a . . . ...113
T a b l e 5 . 5 . 1 - P C A s t a t i s t i c s . . . . ... . . . 1 1 2 6 F U R T H E R D I G I T A L P R O C E S S I N G T a b l e 6 . 2 . 1 - L a n d s a t 2b c a l i b r a t i o n c o e f f i c i e n t s . . . 121
F i g u r e 6 . 4 . 1 - L a n d s a t 2b r a d i o m e t r i c look up t a b l e s . ... 126
F i g u r e 6 . 4 . 2 - V a r i a t i o n in r e f l e c t a n c e look up t a b l e s w i t h su n a n g l e . . . ... 126
T a b l e 6 . 4 . 1 - T h e e f f e c t of c a l i b r a t i o n on b a n d d i f f e r e n c e s . ... 128
T a b l e 6 . 5 . 1 - R a w d a t a P C A s t a t i s t i c s . . . ... ... . . 1 3 1 T a b l e 6 . 5 . 2 - C a l i b r a t e d d a t a P C A s t a t i s t i c s ... . . . . 1 3 2 F i g u r e 6 . 5 . 1 - P r i n c i p a l c o m p o n e n t l o a d i n g s ... 133
T a b l e 6 . 6 . 1 - T w o d i m e n s i o n a l soil line d a t a . ... 137
P l a t e 6 . 6 . 1 - PVI v e g e t a t i o n m a p . . . ... .140
7 C O N C L U S I O N S A ND R E C O M M E N D A T I ONS
T a b l e 7 . 3 . 1 - T h e d i s t a n c e Dn th e g r o u n d r e p r e s e n t e d by
5 1 2 p i x e l s for a r a n g e of d i f f e r e n t s e n s o r s . 148
C H A P T E R
I N T R O D U C T I O N
1.1 I N T R O D U C T ION
T h e r o l e t hat r e m o t e s e n s i n g can p l a y in s u r v e y s of s e m i - a r i d a g r i c u l t u r e and r a n g e l a n d is p o t e n t i a l l y an i m m e n s e one. Th e a b i l i t y tD d e t e c t and m a p v e g e t a t i o n and t e r r a i n o v e r large and o f t e n i n a c c e s s i b l e areas, s uch as E g y p t ’s co a s t a l strip, m a k e s r e m o t e s e n s i n g an o b v i o u s c h o i c e as a m a p p i n g tool. W h i l s t t h i s o b s e r v a t i o n m a y be t r u e in a g e n e r a l s e n s e it is n e c e s s a r y to c o n s i d e r at w h a t level a r e m o t e s e n s i n g input w o u l d be most a p p r o p r i a t e . Th e t e r m ’ l e v e l ’ , here, has a v a r i e t y of m e a n i n g s . It can be t aken to m e a n level as in scale, ie th e s c a l e of i m a g e r y w h e t h e r p h o t o g r a p h i c Dr MS S data, it can a l s o be ta k e n to m e a n the level of s o p h i s t i c a t i o n at w hi c h r e m o t e l y sens e d d a t a a r e i n t e g r a t e d into a survey. Th e p o t e n t i a l of r e m o t e l y s e n s e d d a t a is g r e a t indeed, but p r a c t i c a l i t i e s in t e r m s of the a v a i l a b i l i t y of data, p r o c e s s i n g f a c i li t i e s , c l i m a t e , cost, p o l i t i c s , sociology, t i m e l i n e s s and a host of o t h e r f a c t o r s s e r v e to limit t h a t p o t e n t i a l . R e m o t e s e n s i n g must, in o r d e r to m a k e an e f f e c t i v e c o n t r i b u t i o n , be a p p r o p r i a t e .
T h e r e m o t e s e n s i n g input to the S A M D E N E and R E M D E N E s t udies, w h i c h c o m m e n c e d in 1974, has for th e m o s t par t b e e n in the f orm of aer i a l p h o t o g r a p h y . T h i s has p r o v e d a v a l u a b l e s o u r c e of
i n f o r m a t i o n , at a level at w h i c h it can c o n t r i b u t e to d i v e r s e s t u d i e s r a n g i n g f r o m s o i l s m a p p i n g and e r o s i o n e s t i m a t i o n to v e g e t a t i o n m a p p i n g . A e r i a l p h o t o g r a p h y at a s c a l e of 1 : 2 0 0 0 0
is u n d o u b t e d l y an a p p r o p r i a t e input. It is, however, e x p e n s i v e , p a r t i c u l a r l y w he n r e p e a t e d c o v e r a g e is r e q u i r e d and it is not g e n e r a l l y in the p u b l i c d o m ain. At w hat level though, can s a t e l l i t e r e m o t e s e n s i n g c o n t r i b u t e to w i d e r a n g i n g e c o l o g i c a l
3
s t u d i e s such as S A M D E N E and R E M D E N E ? Had a c o n s c i o u s d e c i s i o n b e e n m a d e to use s a t e l l t e d a t a at the o u t s e t of t h e s e s t u d i e s then o n l y a r e l a t i v e l y small n u m b e r of 1a b o r a t o r i e s ,
p r i n c i p a l l y in the U n i t e d S t a t e s , c o u l d h ave m a d e a r i g o r o u s m u 11 i - t e m p o r a l di g i t a l s t u d y of the e n v i r o n m e n t . T h e h i s t o r i c a l fac t that L a n d s a t s on e to t h r e e <1972 - 1982) w e r e p r i n c i p a l l y r e s e a r c h s a t e l l i t e s and t h a t c o m m e r c i a l l y a v a i l a b l e c o m p u t e r t e c h n o l o g y , in p a r t i c u l a r s o f t w a r e , is only j u s t b e c o m i n g g e n e r a l l y a v a i l a b l e on a n a t i o n a l b a s i s (in the U K at least), h a s m e a n t that r e m o t e s e n s i n g has not been a b l e to p l a y an i m p o r t a n t r o l e in t h e s e two e c o l o g i c a l s u rveys. In a d d i t i o n b e c a u s e of th e p o l i t i c a l i n t e r a c t i o n s b e t w e e n the E g y p t i a n R e m o t e S e n s i n g C e n t r e in C a i r o and o t h e r bodies, s u c h as A l e x a n d r i a U n i v e r s i t y , an i n d i g e n o u s E g y p t i a n r e m o t e s e n s i n g input to the s t u d i e s has not b e e n f o r t hc o m i n g .
A s i g n i f i c a n t input to the s t u d i e s f r o m s a t e l l i t e r e m o t e s e n s i n g has, d u e to the c o n s t r a i n t s m e n t i o n e d a b o v e and th e fact that the R E M D E N E s t u d y o f f i c i a l l y f i n i s h e d in 1984, not b e e n p o s s i b l e . How e v e r , it m a y be that th e m o s t i m p o r t a n t c o n t r i b u t i o n that s a t e l l i t e r e m o t e s e n s i n g can o f f e r to the re g i o n will b e in th e f u t ure, by m o n i t o r i n g the c h a n g e s w h i c h a r e o c c u r r i n g w i t h i n the c o a s t a l tr a c t due to th e i n c r e a s i n g e c o l o g i c a l p r e s s u r e b e i n g e x e r t e d by man.
P r o b a b l y the m o s t i m p o r t a n t m o n i t o r i n g r o l e w h i c h r e m o t e s e n s i n g m a y b e a b l e to p e r f o r m is in m o n i t o r i n g th e s p a tial e x te n t and q u a l i t y of th e r a n g e l a n d v e g e t a t i o n . T h e p o s s i b i l i t y of r e m o t e s e n s i n g b e i n g a b l e to c o n t r i b u t e to t h i s s p e c i f i c end is m a r g i n a l . T h e p o t e n t i a l b e n e f i t s ,however, m o r e than j u s t i f y th e c o s t s of i n v e s t i g a t i o n .
Th e a c t i v i t i e s of t h e R E M D E N E (Regional Env i r o n m e n tal M a n a g e m e n t of M e d i t e r r a n e a n D e s e n t E c o s y s t e m s of N o r t h e r n Egypt) p r o j e c t h a v e b e e n f o u r f o l d :
First, ’r e p r e s e n t a t i v e s e c t o r s ’ of the co a s t a l s t r i p h a v e b e e n m a p p e d tD p r o v i d e i n f o r m a t i o n on t o p o g r a p h y , soils, h y d r o l o g y , v e g e t a t i o n , and a n c i e n t and m o d e r n land u s e s y s t e m s .
Seco n d l y , a p r o c e d u r e for land r e s o u r c e s a s s e s s m e n t h as b een d e v i s e d i n v o l v i n g t h e i d e n t i f i c a t i o n and d e s c r i p t i o n of land u n i t s on the b a s i s of the c r i t e r i a m e n t i o n e d above. T h e s e u n i t s ar e t hen e v a l u a t e d in t e r m s of the d e g r e e to w h i c h they h ave b een a f f e c t e d by man, ie to w hat e x t e n t t he y a r e a f f e c t e d by u r b a n i z a t i o n , g r a z i n g , a g r i c u l t u r e , ero s i o n , s h r u b c u t t i n g , w a t e r u s e etc.
T h i rdly, t he v a r i o u s d i f f e r e n t f o r m s of l a n d u s e w h i c h h a v e b e e n p r e v a l e n t t h r o u g h o u t the r e g i o n d u r i n g the p a s t f e w d e c a d e s have been s t u d i e d an d t h e i r e f f e c t s u pon t he r e g i o n ’s
e c o s y s t e m s e s t a b l i s h e d .
F o u r t h l y , th e e c o s y s t e m s t h e m s e l v e s h a v e b e e n m o d e l l e d in o r d e r to try and a s s e s s and d e s c r i b e th e e f f e c t of e x o g e n o u s f a c t o r s upo n them. (Source R E M D E N E 1983).
T h e p u r p o s e of thi s t h e s i s has b e e n to e x a m i n e th e d i f f e r e n t t e c h n i q u e s a v a i l a b l e for v e g e t a t i o n m a p p i n g u s i n g v i s i b l e and
i n f r a r e d r e m o t e l y s e n s e d d a t a in the c o n t e x t of n o r t h e r n Egypt.
S i n c e th e L a n d s a t d a t a u s e d in t h i s s t u d y w e r e a c q u i r e d , m a n y t h i n g s h a v e c h a n g e d in t h e r e m o t e s e n s i n g world. N e w s e n s o r s
h ave b een i n t r o d u c e d and l a r g e s c a l e v e g e t a t i o n m o n i t o r i n g has b e c o m e p o s s i b l e on an o p e r a t i o n a l b a s i s w i t h the i n t r o d u c t i o n o-f the N O A A G l o b a l V e g e t a t i o n Index <6VI) p r o d u c t . In a d d i t i o n the c o n c e p t of G e o g r a p h i c I n f o r m a t i o n S y s t e m s (GIS) has b e c a m e v o g u e in r e l a t i o n to r e m o t e l y s e n s e d data. All of t h e s e
d e v e l o p m e n t s h a v e i m p l i c a t i o n s w i t h r e s p e c t to v e g e t a t i o n m a p p i n g in Egypt. It ha s b e c o m e m y o p i n i o n that o n l y w i t h the
i n t r o d u c t i o n of p o w e r f u l s mall s c a l e c o m p u t e r s y s t e m s w h i c h t a k e full a d v a n t a g e of the r e s o l u t i o n of N Q A A A V H R R d a t a and w h i c h a l l o w c o m p a r i s o n s to be m a d e w i t h d a t a f r o m o t h e r s o u r c e s
in the f r a m e w o r k of a r e g i o n a l g e o g r a p h i c i n f o r m a t i o n system, will t r u e l y u s e f u l o p e r a t i o n a l s y s t e m s b e c o m e a v a i l a b l e . S u c h
i n f o r m a t i o n s y s t e m s , in w h i c h r e m o t e l y s e n s e d d a t a w o u l d be o n l y a c o m po n e n t , ca n c l e a r l y act as a ids to r e g i o n a l r e s o u r c e m a n a g e m e n t and p l a n n i n g . T h e u t i l i t y and m e r i t s of suc h
i n f o r m a t i o n s y s t e m s s p e c i f i c a l l y d e s i g n e d for us e in S o m a l i a h a v e b e e n d i s c u s s e d by W a t s o n and N i m m o (19S5).
T h e p h y s i c a l , c o n c e p t u a l a nd t e c h n o l o g i c a l e l e m e n t s of new r e s o u r c e m a n a g e m e n t t o o l s n ow exist. It r e m a i n s to be seen, however, to w h a t e x t e n t t h e s e ne w t ools will be d e v e l o p e d in the c o n t e x t of the d e v e l o p i n g w o r l d and to w h a t e x t e n t t h e y will impact u p o n real p r o b l e m s w i t h i n the social and e c o n o m i c
r e s t r a i n t s in w h i c h t hey will b e c on s t r a i n e d .
T h i s t h e s i s a d d r e s s e s the t e c h n i q u e s for v e g e t a t i o n m a p p i n g in arid regions. It s h o u l d be b o r n in mind, h o w ever, that t h e s e t e c h n i q u e s f o r m o n l y an e l e m e n t w i t h i n the lar g e r task of p r o v i d i n g m e a n i n g f u l d a t a in a u s e a b l e and u s e f u l form.
C H A P T E R 2 T H E S T U D Y A R E A
2.1 L O C A T I O N AN D P H Y S I O G R A P H Y
T h e s t u d y a r e a of t h i s t h e s i s w a s o r i g i n a l l y d e f i n e d as b e i n g the w h o l e of the c o a s t a l tr a c t of n o r t h e r n E gy p t b e t w e e n A l e x a n d r i a , in the east, and S a l u m in the west, n e a r E g y p t ’s
b o r d e r w i t h Libya. Du e to the p r o b l e m s of p h y s i c a l l y h a n d l i n g such large q u a n t a t i e s of d a t a (four full L a n d s a t s c e n e s ) and of the need to f o c u s a c t i v i t y , two small s u b - a r e a s w e r e chosen.
T h e s e s u b - a r e a s w e r e c h o s e n so that they c o v e r e d th e R E M D E N E s t u d y ’s T r a n s e c t s 1 and 3. T h e s e two a r e a s w e r e p i c k e d b e c a u s e they are r e p r e s e n t a t i v e of m u c h of the c o a stal t r ac t and
c h a r a c t e r i s e the c l i m a t e and p h y s i o g r a p h y of la r g e r e g i o n s w i t h i n it. In a d d i t i o n , th e s t a f f of the R E M D E N E p o j e c t h a v e s t u d i e d t h e s e two t r a n s e c t s in detail and t h e r e is t h e r e f o r e m u c h i m p o r t a n t d a t a r e c o r d e d f o r the two sites. T h e t r a n s e c t s a r e als o w i t h i n e a s y s t r i k i n g d i s t a n c e f ro m A l e x a n d r i a fo r the p u r p o s e s of f i e l d w o r k .
F i g u r e 4. 1 . 1 s h o w s .the c o a s t a l tract and th e l o c a t i o n of the n ine R E M D E N E t r a n s e c t s , n u m b e r s on e and t h r e e b e i n g the s t u d y a re a s for t h i s thesis. T h e tw o t r a n s e c t s a r e c e n t r e d on the towns of B u r g el A r a b and El O m a y e d r e s p e c t i v e l y .
T h r e e m a j o r p h y s i o g r a p h i c s y s t e m s (1) e x i s t a l o n g th e e x t e n t of the c o a s t a l tract. T h e s y s t e m w h i c h we ar e p r e d o m i n a n t l y
c o n c e r n e d w i t h h e r e is t hat b e t w e e n A l e x a n d r i a and El Daba, T h i s s y s t e m is c h a r a c t e r i s e d by the p h y s i o g r a p h i c u n i t s f o u n d
(1) A p h y s i D g r a p h i c s y s t e m is a p h y s i c a l l y h o m o g e n e o u s u n i t or g ro u p of u n i t s w h i c h c h a r a c t e r i z e th e landscape.
at El Omayed. F i g u r e 2 . 1 . 1 s h o w s an e l e v a t i o n c r o s s - s e c t i o n taken t h r o u g h T r a n s e c t 3 -from t he c o a s t to s o m e ten k i l o m e t r e s
inland. T h r e e p h y s i o g r a p h i c s y s t e m s have b e e n i d e n t i f i e d w i t h i n this m a j o r p h y s i o g r a p h i c s y s t e m (RE M D E N E 1981). T h e th r e e s y s t e m s are: first, t he 'coastal s y s t e m ’ w h i c h c o n s i s t s of the b e a c h and the c o a s t a l s a n d dunes, t h i s s y s t e m is v e r y d i s t i n c t i v e , S e c o n d , th e 'ri d g e and d e p r e s s i o n s y s t e m ’ w h i c h c o n s i s t s of a s e r i e s D f r i d g e s and d e p r e s s i o n s w h i c h run
p ar a l l e l w i t h th e c o a s t an d a r e the r e m n a n t s of f o r m e r c o a s t a l d u n e systems. Third, the 'inland s y s t e m ’ w h i c h c o n s i s t s of an
inland p l a t e a u w h i c h s l o p e s g e n t l y u p w a r d s and g e n e r a l l y to t h e s o u t h - e a s t .
T h e co a s t a l s y s t e m c an b e f o u n d a l o n g the e n t i r e e x t e n t of t h e c o a s t and is q u i t e a p p a r e n t on the s a t e l l i t e images, it
a p p e a r s as a b r i g h t w h i t e s t r i p f o l l o w i n g the c o a s t line. T h e r i d g e and d e p r e s s i o n s y s t e m c an be f o u n d at v a r i o u s p l a c e s a l o n g the c o a s t but is v e r y v a r i a b l e in t e r m s of th e w i d t h and d e e p n e s s of th e d e p r e s s i o n s . It is p a r t i c u l a r l y p r o m i n e n t b e t w e e n A l e x a n d r i a and El A l e m e i n . It can b e s e e n f r o m t he F i g u r e 2 .1.1 tha t at El O m a y e d the d e p r e s s i o n s a r e b r o a d and
s h a l l o w w ith th e land r i s i n g t o w a r d s th e south. At t h i s
p o s i t i o n a l o n g the coast, th e inland p l a t e a u r i s e s s t e e p l y f r o m a bout f i f t e e n to t w e n t y m e t r e s a b o v e s e a level at i t ’s base, to ab o u t e i g h t y m e t r e s a b o v e s e a level at i t ’s h i g h e s t point.
P l a t e 2. 1 . 1 s h o w s a v i e w l o o k i n g s o u t h w a r d s j u s t o u t s i d e the t own of El O m a y e d . In t h e d i s t a n c e the r i d g e of K h a s h m El E i s h
is visible, t h i s b e i n g t he e d g e of the inland p l a t e a u ; w h i l s t in the f o r e g r o u n d s c a t t e r d s h r u b s of T h y m e l i a H u s u t a , an i m p o r t a n t s h r u b in t h e m a k e up of the range, a r e v is i b l e . T h e
R E M D E N E p o j e c t has i d e n t i f i e d f i f t e e n p h y s i o g r a p h i c u n i t s w h i c h m a k e up th e t h r e e b a s i c s y s t e m s .
T h e s e u n i t s a r e a n n o t a t e d on F i g u r e 2.1.1 and ar e t a b u l a t e d in T a b l e 2.1.1. U n i t 7a, ' w a t e r l o g g e d d e p r e s s i o n ’ , is g e n e r a l l y
l o c a l i s e d to r e l a t i v e l y s m a l l a r e a s in T r a n s e c t 3 bu t in T r a n s e c t 1 f o r m s t h e b a s i s f or L a k e Mariut. At B u r g El A r a b
( T ransect 1) the p h y s i o g r a p h i c s y s t e m s are e s s e n t i a l l y t h e s a m e but d i f f e r in t h e d e t a i l D f t he units. In T r a n s e c t 1,
p h y s i o g r a p h i c u n i t 7 is c o m p l e t e l y i n u n d a t e d w i t h s a l i n e w a t e r and is c o n s i d e r a b l y wider. Th e s e c o n d and t h i r d r o c k y r i d g e s a r e still p r e s e n t bu t the inla n d p l a t e a u is r e a c h e d by g e n t l y r i s i n g g r o u n d o v e r the r i d g e s r a t h e r than v i a a s t e e p
e s c a r p m e n t as in u n i t 13 of T r a n s e c t 3. To th e w e s t of El O m a y e d the inland p l a t e a u and the s y s t e m of r i d g e s and d e p r e s s i o n s p r o g r e s s i v e l y d i v e r g e f r o m the coast.
T h e o t h e r t wo m a j o r l a n d s c a p e t y p e s w h i c h o c c u r a l o n g th e c o a s t ar e first, th e m a j o r s y s t e m w h i c h o c c u r s in the D a b a a / F u k a a r e a and w h i c h is c h a r a c t e r i s e d by h i l l s and r i d g e s and b r o a d level v a l l e y s ; and se c o n d , the s y s t e m wh i c h is f o u n d f u r t h e r w e s t and w h i c h c o n s i s t s of u p l a n d p l a i n s incised by d e e p b r o a d w a d i s w h i c h d r a i n into th e sea. T h i s last s y s t e m g e n e r a l l y o c c u r s to
th e w est of M e r s a M a t r u h and is c h a r a c t e r i s e d by Wadi G a r a w l a . A d e s c r i p t i o n of p h y s i o g r a p h i c f e a t u r e s w h i c h a r e v i s i b l e on the L a n d s a t i m a g e r y a p p e a r s in c h a p t e r four.
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Figure2.1.1 ThephysiographicunitspccuringatElOmayed.(SourceREMDENE1983)
11
T A B L E 2.1.1
U N I T No D E S I G N A T I O N D I S T A N C E G E O L O G I C A L AN D
F R O N C O A S T G E O M Q R F H Q L Q G I C A L F E A T U R E S b e a c h
co a s t a l d u n e s
0 - 2 0 0 m
2 0 0 -5 0 0 m p r e s e n t a c t i v e d u n e s on c o n s o l i d a t e d m a t e r i a l . f i r s t d e p r e s s i o n
n o r t h e r n s l o p e of 1st r o c k y r i d g e f i r s t r o c k y r i d g e
5 0 0 - 9 00 m
6 0 0 - 9 0 0 m
9 0 0 - 1 100m
f l a t and s t r e t c h e d
d e p r e s s i o n (sand d e p o s i t s ) . h i l l s i d e (sandy c o l l u v i o n s )
s u m m i t of s t r e t c h e d hill ( o olitic l i m e s t o n e ta
a n c i e n t c o n s o l i d a t e d dune).
10
s o u t h e r n s l o p e of 1 - 1 . 3k m 1st r o c k y r i d g e
s a l i n e d e p r e s s i o n :
. s alt m a r s h 1 . 1 - 2 . 5km . h u m m o c k y d e p r e s s i o n i . l - 3 k m
. s a n d y m e s o - d e p o s i t l . l - 3 k m . s a n d y i n d u r a t e d 2km
c o n - c D n v e x i t y
s e c o n d r o c k y r i d g e 3 - 3 . 3 k m
i n t e r i d g e s s a n d y s l o p e 3 - 3 . 3k m
t hird r o c k y r i d g e 4 . 3 - 4 . 6km
h i l l s i d e (sandy c o l l u v i o n s )
w a t e r l o g g e d d e p r e s s i o n (loamy an d c l a y e y sand), flat a r e a (lo c a l l y
w a t e r l o g g e d w it h n u m e r o u s s a n d y h u m m o c k s ) .
g e n t l y an d i r r e g u l a r l y s l o p i n g s a n d y hill,
low and s t r e t c h e d
c o n v e x i t y ( i n d u r a t e d sand).
s u m m i t of s t r e t c h e d hill ( o olitic l i m e s t o n e - a n c i e n t c o n s o l i d a t e d d e p o s i t s ) .
g e n t l y s l o p i n g s u r f a c e o v e r l a i n by d r i f t e d sand.
s u m m i t of s t r e t c h e d hill (ooliti l i m e s t o n e - a n c i e n t c o n s o l i d a t e d d e p o s i t s ) .
11 s o u t h e r n s a n d y s l o p e Df 3r d r o c k y r i d g e 12 n o n - s a l i n e f lat
d e p r e s s i on
4 . 6 - 6 k m g e n t l y s l o p i n g s u r f a c e o v e r lain by d r i f t e d sand.
5 . 5 - 7 k m p l a i n m o r e or less d r i f t e d .
13
14
15
s a n d y g l a s i s w i t h g u 1 1 i es
c l i f f and o u t c r o p of inland p l a t e a u
u n d u l a t i n g s a n d y s u r f a c e
6 . 5 - 8 . 5km s a n d y g l a c i s d i s s e c t e d w i t h g u l l i e s in the u p p e r part.
7 . 5 - 8 . 5km c l i f f w i t h o u t c r o p of c a l c a r e o u s s a n d s t o n e a n d s t r e t c h e d and g e n t l y s l o p i n g inl a n d p l a t e a u .
8 - 1 0 k m s l i g h t l y u n d u l a t i n g s u r f a c e w i t h d r i f t e d sand.
2 . 2 C L I M A T E
2 .2.1 F a c t o r s D e t e r m i n i n g C 1 imate
F A O (1970) i d e n t i f i e s f o u r p i n c i p a l f a c t o r s w h i c h d e t e r m i n e the c l i m a t e a l o n g the n o r t h e r n c o a s t a l tract:
(1) T h e s i t u a t i o n D f t he r e g i o n with r e g a r d to t h e g e n e r a l c i r c u l a t i o n of th e a t m o s p h e r e .
(2) T h e p r o x i m i t y of th e M e d i t e r r a n e a n sea.
(3) T h e o r i e n t a t i o n of t he coast.
(4) T h e o r o g r a p h y .
F a c t o r o n e is c o n t r o l l e d by t h e s u b t r o p i c a l h igh p r e s s u r e b e l t in s u m m e r and by t he eye 1 o n e * m o v i n g e a s t w a r d s w i t h w e s t e r l i e s in winter. T h e s u m m e r m o n t h s a r e c h a r a c t e r i s e d by c l e a r skies no rain, h i g h s o l a r r a d i a t i o n and light winds. D u r i n g the w i n t e r m o n t h s , N o v e m b e r to April, A t l a n t i c and M e d i t e r r a n e a n c y c l o n e s e x t e n d s u f f i c i e n t l y fa r e a s t w a r d s to a c c o u n t for v i r t u a l l y all of th e w i n t e r r a i n f a l l w h i c h is a s s o c i a t e d w i t h c o l d f r o n t c u m u l u s c l o uds. F a c t o r s (2) and (3) a f f e c t th e air t e m p e r a t u r e and h u m i d i t y and t h e v a r i a t i o n in r a i n f a l l a l o n g t h e coast.
2 . 2 . 2 A v e r a g e Pi stri b u t i o n of R a infall
F A O (1970) q u o t e s th e v a l u e s s h o w n in F i g u r e 2 . 2 . 1 as b e i n g th e m e a n a n n u a l r a i n f a l l f i g u r e s in mm, for the t h i r t y y e a r p e r i o d
1 9 2 5 - 1 9 3 9 , 1 9 5 1- 1 9 6 5 . F a c t o r (3) a b o v e is c i t e d a s b e i n g the m a i n c o n t r i b u t o r to th e v a r i a t i o n s in m e a n a n n u a l r a i n f a l l
P l a t e 2 .1.1
A s o u t h e r l y v i e w at El O m a y e d t o w a r d s th e inland p l a t e a u and th e r i d g e of K h a s h m el Eish.
^ I
2MUexandria
Surg c l Arab t i rmsua
Iuia
latlta
« i' I 1— !--- !- T ^ I ■ IT *-T j Distance fro * Alexandria Vr
F i g u r e 2.2.1
M e a n annual r a i n f a l l in m m at s e l e c t e d l o c a t i o n s a l o n g the coast.
S o u r c e F A O (1970)
14
a l o n g the c o a s t a l tract* T h e e x t r e m e v a r i a b i l i t y , b o t h
s p a t i a l l y and t e m p o r a l l y , in t h e r a i n f a l l and th e s p a r c i t y of r e l i a b l e d a t a b o t h c o n t r i b u t e to the d i f f i c u l t y in d e f i n i n g
isohytes. T h e r ai n y s e a s o n c o m m e n c e s d u r i n g the s e c o n d p a r t of O c t o b e r and l asts u ntil m i d Marc h . F i g u r e 2 . 2 . 2 s h o w s the
s e a s o n a l d i s t r i b u t i o n D f r a i n f a l l at El Daba, w i t h s e v e n t y f i v e p e r c e n t of th e annu a l total f a l l i n g b e t w e e n N o v e m b e r and
F e b r u a r y . F i g u r e 2 . 2 . 3 s h o w s th e r e l a t i o n s h i p b e t w e e n r ai n f a l l and the d i s t a n c e f r o m the coast, the r e l a t i o n s h i p b e i n g m o s t s tr i k i n g .
T h e v er y low m e a n a n n u a l v a l u e s , all of w h i c h a r e b e l o w 2 0 0 m m in F i g u r e 2.2.1, i m p o s e v e r y s e v e r e c o n s t r a i n t s u p o n d r y l a n d f a r m i n g in t h e region. T h e n a t u r e D f the c u r v e in F i g u r e 2 . 2 . 3 m e a n s that an y d r y l a n d f a r m i n g w h i c h d oe s e x i s t in the r e g i o n
is c o n f i n e d to a r e a s v e r y c l o s e to the coast. F A O (1970) s t a t e that d r y l a n d f a r m i n g is ' p r a c t i c a l l y i m p o s s i b l e w i t h a r a i n f a l l w h i c h is s d s c a r c e and e r r a t i c ' , w h i l e Ka y et al (1985) r e g a r d 5 0 0 m m as b e i n g the m i n i m u m r a i n f a l l fo r 'normal' r a i n f e d
fa rming. A r n o n (1972) s t a t e s t h a t a f i g u r e of 5 0 0 m m is for a r e a s w i t h s u m m e r r a i n f a l l and E r i c h a m b a u t and W a l l e n (1963) q u o t e a m i n i m u m m e a n annual r a i n f a l l of 2 4 0 m m w i t h a v a r i a b i l i t y of 37 pe r cen t as b e i n g th e m i n i m u m a m o u n t f o r v i a b l e r a i n f e d p r o d u c t i o n . A l t h o u g h the m e a n a n n u a l v a l u e s in F i g u r e 2 . 2 . 1 a r e all b e l o w 2 0 0 m m d r y l a n d f a r m i n g is, n e v e r t h e l e s s , p r a c t i s e d in . th e region, as it ha s b e e n f or t h o u s a n d s Df years. Not o n l y is th e rai n f a l l h i g h l y v a r i a b l e s p a t i a l l y and t e m p o r a l l y w i t h i n in d i v i d u a l years, it is a l s o v e r y v a r i a b l e on an i n t e r a n n u a l basis. F A O (1970) c a l c u l a t e t hat the r e l a t i v e i n t e r a n n u a l v a r i a b i l i t y at El D a b a is in t h e o r d e r of f o r t y p e r cent.
A u t u m n
S u m m e r S e a s o n a l R a i n f a l l at El D a b a
F i g u r e 2 . 2 . 2
S e a s o n a l r a i n f a l l at El Daba.
S o u r c e F A O (1970)
13?
D i stance froa the coast
F i g u r e 2 . 2 . 3
T h e r e l a t i o n s h i p b e t w e e n r a i n f a l l and d i s t a n c e f r o m th e coast.
S o u r c e F A O (1970)
16
In such c o n d i t i o n s th e i m p o r t a n c e of m o i s t u r e d e r i v e d f r o m d e w is c o n s i d e r a b l e to b o t h f l o r a an d fauna. M i g a h i d and A y y a d (1959) e s t i m a t e d t hat d u r i n g 1 9 5 5 the total annu a l d e p t h of d e w f a l l as b e i n g 115mm. T h i s v a l u e b e i n g half as m u c h a g a i n as th e m e a n annu a l r a i n f a l l . T h e p r o p o r t i o n of t hi s f i g u r e w h i c h w o u l d h a v e b e e n a v a i l a b l e to p l a n t s is h o w e v e r o p e n to debate.
In a d d i t i o n , F A O ( 1970 pp26) q u e s t i o n the e f f e c t s of the
p h y s i c a l p r o p e r t i e s of th e D u d v e d a n i d e w g a u g e (used by M i g a h i d and Ayyad) on th e v o l u m e of d e w co l l e c t e d .
F i g u r e 2 . 2 . 4 s h o w s th e r e l a t i o n s h i p b e t w e e n p r e c i p i t a t i o n and p o t e n t i a l and a c t u a l e v a p o t r a n s p i r a t ion t h r o u g h o u t the y ea r at B u r g el Arab. It is c l e a r f r o m t he f i g u r e t hat o n l y f r o m mi d N o v e m b e r Id t h e end D f F e b r u a r y d o e s a s u r p l u s of m o i s t u r e e x i s t w i t h i n the r o o t i n g zone.
In c o n c l u s i o n , F A O (1970) d e s c r i b e s the c l i m a t e of the n o r t h e r n c o a s t of E g y p t as b e i n g ’o n e of the m i l d e s t of t h e
M e d i t e r r a n e a n ’ w i t h h igh w i n t e r t e m p e r a t u r e s and r e a s o n a b l e s u m m e r ones, w i t h r e l a t i v e l y h ig h air h u m i d i t i e s . T he l i m i t i n g f a c t o r to a g r i c u l t u r e , h o w e v e r , b e i n g the h igh v a r i a b i l i t y of the r a i n f a l l in all D f i t ’s a s p e c t s .
1 /
F o u n t.a t s v i5 0 ira r.i? iri
A c t u a l E r a p o t r a n s p i r a t i c n - U t i l i z a t i o n
F i g u r e 2 . 2 . 4
S e a s o n a l w a t e r balance.
S o u r c e R E M D E N E 1983
P l a t e 2 . 3 . 2
B a r l e y m o u n d s used for the s t o r a g e o-F
s u r p l u s g r a i n g r o w n d u r i n g good y e a r s of d r y l a n d p r o d u c t i o n .
18
2 . 5 A G R I C U L T U R E
2.3.1 I R R I G A T E D A G R I C U L T U R E
T h e n i n e t e e n s i x t i e s s a w th e i m p l e m e n t a t i o n of g o v e r n m e n t a l rural m a n a g e m e n t p o l i c y in th e B u r g el A r a b area, and w i t h it g r e a t c h a n g e s in t h e r e g i o n ’s a g r i c u l t u r a l p r a c t i c e and
s o c i o l o g i c a l s t r u c t u r e , an d s p e c i f i c a l l y in the m o b i l i z a t i o n of t h e labour force. S o l i m a n (1981) i n d e n t i f i e s t h r e e m a j o r
a s p e c t s of t h e r e s u l t i n g c h a n g e s . T h e s e being:
(1) A g r e a t i n c r e a s e in th e a v a i l a b l e c u l t i v a t e d land, w h i c h w a s r e c l a i m e d by b o t h the s t a t e and by i n d i vi d u a l s .
(2) A s h o r t a g e of w a t e r as a r e s u l t of the vast i n c r e a s e in land r e c l a m a t i o n . T h i s l i m i t e d the p o s s i b i l i t i e s of c u l t i v a t i o n of all th e r e c l a i m e d land.
(3) A d e c r e a s e in th e a r e a a v a i l a b l e for gra z i n g .
T h e land " r e c l a i m e d ’ by i n d i v id u a l s , in a d d i t i o n to t hat e x p r o p r i a t e d b y th e state, led to an i n c r e a s e in w a t e r d e m a n d
ab o v e and b e y o n d th e d e s i g n s u p p l y of the ne w i r r i g a t i o n s y s tems. This, c o u p l e d w i t h h i g h w a t e r los s e s t h r o u g h the u n l i n e d canal w a l l s and t h e d i v e r s i o n of i r r i g a t i o n w a t e r to o r c h a r d s , led d i r e c t l y to w a t e r s h o r t a g e s and s a l i n i z a t i o n in
1d w l ying a r e a s and t h o s e a r e a s a d j a c e n t to the c a n a l s . I h a v e m y s e l f s e e n s a l i n i z e d o l i v e o r c h a r d s a d j a c e n t to t he i r r i g a t i o n
c a n a l s in B u r g el Arab. I r o n i c a l l y p o t e n t i a l l y p r o d u c t i v e land has b e e n lost b o t h t h r o u g h a lack of i r r i g a t i o n w a t e r on the o n e hand and b y s a l i n i z a t i o n t h r o u g h e x c e s s i v e w a t e r s e e p a g e and i r r i g a t i o n on t h e other.
Th e c r o p s w h i c h ar e s u c c e s s f u l l y c u l t i v a t e d in t he B u r g el A r a b a r e a ar e listed below:
W i n t e r c r o p s and o r c h a r d s 1 9 7 9 / 8 0
S u m m e r c r o p s 1 9 7 9 / 8 0
C r o p A r e a
B a r l e y 156
T r i f o l i u m (clover) 36 5
B e a n s 22 9
A l m o n d 20 8
0 1 i v e 359
G u a v a 58
P e a c h e s 17
C i t r u s 5 0
M a i z e 2 6 2
W a t e r M e l o n 187
T o m a t o e s 85
C u c u m b e r s 39
M a r r o w 17
B e a n s 31
C a b b a g e 12
E g g - p l a n t 17
P e p p e r s 5
(fed d a n s )
(Source R E M D E M E 1981 pp4-19)
2 . 3 . 2 D R Y L A N D A G R I C U L T U R E
T h e e x p a n s i o n of i r r i g a t e d a g r i c u l t u r e a r o u n d B u r g el A r a b d u r i n g t he nineteen s i x t i e s w a s a c c o m p l i s h e d at t h e e x p e n s e a-f d r y l a n d a g r i c u l t u r e and r a n g e l a n d r e s o u r c e s . T h e p r i n c i p a l c ro p c u l t i v a t e d by rain-fed -farming a l o n e is b a r ley. T r e e crops,
w hi c h m a i n l y c o n s i s t o-f o l i v e s and figs, a r e a l s o g r o w n w i t h o u t the aid of i r r i g a t i o n . B o t h the cereal and t r e e c r o p s a r e
c u l t i v a t e d by t he B e d o u i n w h o h a v e b e e n e n c o u r a g e d to s e t t l e p e r m a n e n t l y a l o n g t h e n o r t h e r n c o a s t a l tract.
E v i d e n c e f r o m L a n d s a t i m a g e r y i n d i c a t e s that r a i n f e d c u l t i v a t i o n in the B u r g el A r a b r e g i o n is e x c l u s i v e l y
a s s o c i a t e d w i t h f e a t u r e s k n o w n as "karms*. T h e s e k a r m s a r e of a n c i e n t o r i g i n and w e r e c e r t a i n l y in u s e d u r i n g t h e R o m a n
p e r i o d w h e n t h e t h r e e t h o u s a n d or so d r i n k i n g w a t e r c i s t e r n s , to b e fo u n d in th e r e g i o n w e r e built. R e f e r e n c e s to k a r m s in the
l i t e r a t u r e a r e v e r y s c a n t and no d e f i n i t i v e e x p l a n a t i o n of t h e i r f u n c t i o n s e e m s to exist. T he y are, h o w e v e r , d u e to t h e i r e x c l u s i v e a s s o c i a t i o n w i t h d r y l a n d farming, of no small
i mpo r t a n c e . In a d d i t i o n tD t h e k a r m s F A G (1970) i d e n t i f i e s
" m a n - m a d e 1 s a i l s w h i c h a r e a s s o c i a t e d w ith small a n c i e n t f i e l d s y s t e m s w h i c h a l s o o c c u r in large numbers. T h e s e s m a l l e r f i e l d s y s t e m s a re not i d e n t i f i a b l e on L a n d s a t M SS i m a g e r y and w e r e not k n o w n to local f a r m e r s w h e n i n q u i r i e s w e r e m a d e d u r i n g the
f i e l d visit, c o n s e q u e n t l y t h e y a r e not p u r s u e d f u r t h e r here.
T h e karms, h o w e v e r , w h i c h c o n s i s t of s u b s t a n t i a l e a r t h w o r k s ar e still p r e p a r e d and c u l t i v a t e d e a c h year; r a i n s p e r m i t t i n g . W i t h r e f e r e n c e to t he k a r m s and the a n c i e n t c u l t i v a t i o n m e t h o d s F A O (1970 pp 45) s u g g e s t s that "If it co u l d be d i s c o v e r e d w h a t
21
t h e s e m e t h o d s w e r s and w h y t hey w e r e used, p o s s i b l y they co u l d be a d o p t e d again, and a g r i c u l t u r e in the r e g i o n be i m p r o v e d at 1ow c o s t s ’ ,
T h e k ar m s c o n s i s t Qf •fields of d ee p c l a y loam s o i l s w h i c h are s u r r o u n d e d by b a n k s of soil s o m e t i m e s f i v e m e t r e s or so high
(see P l a t e 2.3.1). F A O (1970) T a b l e IS i n d i c a t e s that the k a r m w a l l s ar e m o r e c o m p a c t e d t h a n the c e n tral f i e l d s w i t h h i g h e r p r o p o r t i o n s of s and and m u c h h i g h e r s a l i n i t y levels. It is s u g g e s t e d by the s a m e a u t h o r that the b a n k s w e r e f o r m e d by the removal Df s a l i n e soil f r o m the central f i e l d w h i c h was t hen d e p o s i t e d at th e f i e l d ’s edge. O t h e r s u g g e s t i o n s to the f o r m a t i o n of th e b a n k s i n c l u d e t h e o r i e s as to th e c r e a t i o n of a m i c r o - c 1 imate and of the b a n k s f o r m i n g do n o r a r e a s for r u n o f f f a rming. D r e g n e (1981) f a v o u r s th e latter e x p l a n a t i o n . An a p p r e c i a t i o n of the s i z e of the k a r m s can b e g a i n e d f r o m P l a t e 2.3.1 w h i c h s h o w s a p a n o r a m i c v i e w of on e of the larger o n e s s o m e t w e l v e k i l o m e t r e s d u e s o u t h of B u r g el Arab. It is c l e a r f r o m th e P l a t e that the s u r r o u n d i n g b a n k s a r e no w s e v e r l y eroded. E v a n a r i et al (1971) s t a t e that a n c i e n t e a r t h w o r k s in the N e g e v a s s o c i a t e d w i t h d r y l a n d f a r m i n g h a v e by now t o t a l l y d i s a p p e a r e d . T h i s is o b v i o u s l y not the c a s e in n o r t h e r n E g y p t a l t h o u g h the k a r m s m a y not be as old as the f e a t u r e s d e s c r i b e d by E v a nari. T h e L a n d s a t M S S i m a g e s p r e s e n t e d in a later c h a p t e r s h o w that c u l t i v a t i o n at t he k a r m s i t e s is not r e s t r i c t e d to t h e inner f i e l d but that s u b s t a n t i a l a r e a s ar e a l s o c u l t i v a t e d s u r r o u n d i n g t h e karms. T h e s h e e r s i z e of the s u r r o u n d i n g banks, e s p e c i a l l y w h e n o n e c o n s i d e r s t hat at on e t i m e t h e y m ay h ave b een c o n s i d e r a b l y larger, l e a d s m e to think that th e n o t i o n of t h e m h a v i n g b e e n f o r m e d b y th e re m o v a l of s a l i n e soil is
22
P l a t e 2.3.1
T h e p e r i m e t e r b a n k s o-f o ne o-f the larger k a r m s to the s o u t h o-f B u r g el Arab.
23
e r r o n e o u s . T h e -fact that c u l t i v a t i o n o c c u r s b o t h i n s i d e and o u t s i d e o-f the k a r m s w o u l d b e i n d i c a t i v e of the b a n k s a c t i n g as d o n o r a r e a s fo r r u n o f f far m i n g . The true n a t u r e of th e k a r m b a n k s h o wever, r e m a i n s a m y s t e r y .
In gDDd y e a r s w h e n y i e l d s ar e s u f f i c i e n t to p r o d u c e a s u r p l u s of grain, th e s u r p l u s is s t o r e d u n d e r m o u n d s of e a r t h as
d e p i c t e d in P l a t e 2.3.2. C o n v e r s e l y in dry y e a r s w h e n t h e r a i n s a r e not s u f f i c i e n t to p r o d u c e a crop, a n i m a l s ar e a l l o w e d
to g r a z e on t h e s h o o t s t hat do emerge. T r a d i t i o n a l l y t he
B e d o u i n s w o u l d c u l t i v a t e b a r l e y f i e l d s at th e b e g i n n i n g ot the wet season, o n l y to r e t u r n w h e n the c r o p s had m a t u r e d . In m o r e r e c e n t t i m e s th e B e d o u i n w h o live l o c ally to B u r g el A r a b
c u l t i v a t e t h e f i e l d s w i t h t r a c t o r s and can r e t u r n e a s i l y to t h e f i e l d s for f u r t h e r c u l t i v a t i o n or to a l l o w g r a z i n g on p o o r l y d e v e l o p e d crops.
2 . 3 . 3 P A S T O R A L A G R I C U L T U R E
T h e B e d o u i n i n h a b i t a n t s of th e c o a s t a l st r i p a r e f a m o u s for t h e i r p a s t o r a l w a y of life. A l t h o u g h m a n y a r e n ow s e t t l e d and a r e sedentary, the t r a d i t i o n a l v a l u e s and f o r m s of w e a l t h remain. T h e p r i n c i p a l c o m m o d i t y and f o r m of s t a t u s and w e a l t h h as t r a d i t i o n a l l y b ee n t he B e d o u i n ’s h e r d s of l i v e s t o c k , w h i c h a r e c o m p r i s e d of sheep, g o a t s and camels, a l t h o u g h the l a t t e r a r e far less p r e v a l e n t in m o d e r n times. E v e n t h o u g h m a n y B e d o u i n g a v e up t h e i r n o m a d i c w a y of lif e d u ri n g the s e t t l e m e n t p e r i o d s of the f i f t i e s and s i x t i e s , m a n y still r e ta i n t h e i r f l o c k s of g o a t s and sheep. T h e r e s u l t ha s been an i n c r e a s e in th e n u m b e r s of l i v e s t o c k c o u p l e d w i t h a d e c r e a s e in t he q u a l i t y and a r e a of
the range. T h e q u a l i t y of th e r a n g e has d e c l i n e d t h r o u g h the p r e s s u r e s Df o v e r g r a z i n g w h i l s t the areal e x t e n t of th e r a n g e has d e c l i n e d as a r e s u l t of th e i n c r e a s e d a r e a of i r r i g a t e d and r e c l a i m e d land. It has a l s o b e e n the c a s e that t h e r a n g e l a n d w h i c h ha s b e e n put to i r r i g a t i o n has b een t hat w h i c h wa s f a v o u r e d by goo d q u a l i t y soils. T h i s g e n e r a l d e c l i n e in the n atural f o r a g e has m e a n t tha t i n c r e a s i n g a m o u n t s of feed m a t e r i a l s f r o m t he d e l t a h a v e had to be u sed in o r d e r to m a i n t a i n the l e v e l s of s t o c k i n g w h i c h now exist. No t o n l y has
the B e d o u i n b e c o m e s e d e n t a r y bu t he has a l s o b e c o m e d e p e n d e n t u p o n th e N i l e D e l t a fo r a r e l i a b l e s u p p l y of s u p p l e m e n t a r y f e e d
stuffs. S o l i m a n and A h m a d (1932) a l s o reg a r d the i n c r e a s e in a nimal n u m b e r s in r e s p o n s e to an e x t ernal d e m a n d as
r e p r e s e n t i n g a d e p e n d e n c e in t h a t the m a r k e t is d r i v e n by e x t e r n a l r a t h e r t han i n t ernal n e e d s and d e m a n d s . T h e s a m e a u t h o r s a l s o h i g h l i g h t t h e p r o b l e m s that a r i s e t h r o u g h
s u p p 1e m e n t a r y f e e d i n g in th e N i l e D e l t a d u r i n g the dr y m o n t h s t h r o u g h the i n f e c t i o n of a n i m a l s by p a r a s i t e s .
F A O (1970) e s t i m a t e s that in t h e c o a stal a r e a s o m e 7 0 p er cen t of the p o p u l a t i o n is i n v o l v e d in p a s t o r a l a c t i v i t y . T h e s e p e o p l e a r e t h e r e f o r e v e r y d e p e n d e n t u po n the e c o n o m i c and e c o l o g i cal we 1-1--be1 ng Df th e region. The e c o l o g i c a l
1
p r e s s u r e s b e i n g e x e r t e d on the e c o s y s t e m a r e i l l u s t r a t e d by the f o l l o w i n g f i g u r e s q u o t e d b y S o l i m a n and A hm a d (1982). T h e
c u r r e n t c a r r y i n g c a p a c i t y of th e r ange in 1971 c a n be e x p r e s s e d by d i v i d i n g th e total s u r f a c e a r e a of the r e g i o n by th e total n u m b e r of ani m a l s :
!
3 5 0 0 0 0 0
--- = 2. 6 F e d d a n s / animal 1 331 0 0 0
(Source S o l i m a n and A hm a d (1982))
T h u s 2 . 6 f e d d a n s ar e a v a i l a b l e for e ach ani m a l f o r g r a z i n g . F A O (1971), h o w e v e r , e s t i m a t e t hat a s u i t a b l e c a r r y i n g c a p a c i t y fo r the r e g i o n w o u l d b e 25 f e d d a n s per animal, w h i l e th e E g y p t i a n A g r i c u l t u r a l D e p a r t m e n t e s t i m a t e s that 50 f e d d a n s pe r animal wo u l d be m o r e a p p r o p r i a t e . T h i s e x a m p l e a m p l y i l l u s t r a t e s the s e v e r e p r e s s u r e b e i n g e x e r t e d on the r e g i o n ’s n a t u r a l r e s o u r c e s .
2 . 4 S O I L S
FA O (1970) r e p o r t s that v i r t u a l l y all of th e s o i l s of the n o r t h e r n c o a st a l t r a c t a r e of a l l u v i a l o r i gin. T h o s e s o i l s not f o r m e d b y a l l u v i a l p r o c e s s e s a r e the r e s u l t o f a e o l i a n
t r a n s p o r t a t i o n and d e p o s i t i o n . All of the r e g i o n ’s s o i l s are d e r i v e d f r o m the l i m e s t o n e b e d r o c k and t h e r e f o r e c o n t a i n high p r o p o r t i o n s of c a l c i u m c a r b o n a t e , b e t w e e n 10 and 15 pe r c e n t in
the top s o i l s and in s o m e c a s e s m u c h higher. A c c u m u l a t i o n s of c a l c i u m c a r b o n a t e and s o d i u m c h l o r i d e o c c u r in t h e a l l u v i a l f a n s and s a l i n e d e p r e s s i o n s r e s p e c t i v e l y .
F A O (1970) i d e n t i f i e s six m a j o r soil c l a s s i f i c a t i o n units, t he s e being:
S o i l s D f the c o a s t a l d u n e s S o i l s of the inl a n d d u n e s
