1. Sediment transport and Coastal
LOGO
erosion
Al-Azhar University-Gaza
Master Program of Water and Environmental
Science

2. Contents
1
Introduction
2
Study Area
3
Materials & Methods
4
Results & Discussion
5
Conclusions
2

3. Mediterranean Sea
1900
1964
00
19
64
19
1971
71
19
88
19
90
19
91
19
1988
96
19
00
20
1990
1991
Rosetta Promontory
1996
2000
Nile River
3
3

4. 1. Introduction
1
2
3
Most sediments coming to Gaza are originally from Nile
River and it is about 350,000 cubic meter annually
(Perlin and Kit, 1999)
Construction of the low Aswan dam in 1902 and the
high Aswan dam in 1964 has almost completely
interrupted the Nile River sediment discharge to the sea
(Inman et al, 1976)
Bardawil lagoon sandbar and Delta continue to act as a
significant source and supplier of sand to Gaza coast
(Inman et al, 1976)
4

5. 1. Introduction
5

6. 1. Introduction
 Alongshore sediment transport can calculate using the following
expressions:
 CERC expression
(1)
 Kamphuis expression
(2)
where
Hb = breaking wave height,
mb = seabed slop,
D50 = characteristic rock diameter,
αb = breaking wave angle.
6

7. 1. Introduction
Annual bulk sediment transport rates for Gaza beach (idku)
Wave
Scenarios
Hs
(m)
Ts
(Sec)
a0
(Deg)
Hb
(m)
H ≤ 1.0m
1.0 < H ≤ 2.0
2.0 < H ≤ 3.0
3.0 < H ≤ 4.0
H > 4.0m
0.5
1.3
2.4
3.4
4.2
6.3
7.1
8.0
8.8
9.4
26
15
17
18
5
0.62
1.46
2.53
3.49
4.32
ab
(Deg)
8
6
8
9
3
Total
Duration Sediment,
m3/year
(d)
289
63
10
2.7
0.3
365
60,746
73,404
48,851
31,050
3,078
220,000
7

8. 1. Introduction
Annual bulk sediment transport rates for Gaza beach (Ashdoud)
Wave
Scenarios
Hs
(m)
Ts
sec)
a0
deg)
H ≤ 1.0m
1.0 < H ≤ 2.0
2.0 < H ≤ 3.0
3.0 < H ≤ 4.0
H > 4.0m
0.67
1
2.25
3.5
3.55
5.9
6.5
7.9
8.8
8.8
-32
35
-13
20
41.2
Hb
m)
ab Duration Sediment
m3/year
deg)
days
Total
197.10
159.86
1.80
3.32
2.92
365
- 65,374
137,138
- 4,807
43,033
47,139
160,000
8

9. 1. Introduction
Sediment transport
The amount of sediment transported along shore 170,000 to
540,000 .(Shoshana G., 2000)
Types of sediment transport
1- Cross shore
9

10. 1. Introduction
Sediment transport
2- Alongshore
10

11. 1. Introduction
In recent decades, the coast of Gaza has been
plagued by a serious shortage of sand and by erosion
11

12. 1. Introduction
The coast of Gaza was affected by man-made structures
prior to the fishing harbour (Zviely and Klein, 2003)
4
In 1972 two groins, 120m long each 500m apart
12

13. 1. Introduction
5
The erosion was controlled by a series of nine
detached breakwaters built in 1978
The detached
breakwaters, 50-120 m
long, were built 50 m
from the coast line at a
depth of 1 m
13

14. 1. Introduction
6
In 1994, the construction of Gaza fishing harbor started
and completed in 1998. The construction negatively
increase the erosion rates
The fishing
harbor extends
some 500m into
the sea,
enabling access
to vessels up to
6m deep.
14

15. 2. Study Area
The study covers an area
extended from Wadi Gaza up to
3km north the Gaza fishing
harbour
15

16. Gaza harbor
16

17. 17

18. 18

19. 3. Materials and Methods
 Data were collected from analyses of Landsat
images from 1972 to 2010 and combined with
sample collection for grain size analyses in
order to study the shoreline change
 Numerical model runs to predict the
morphodynamics around the mitigation
structures were carried out
19

20. 3. Materials and Methods
3.1 Satellite images
The infrared band was selected for
the subsequent image processing.
The image processing procedures
were carried out using ERDAS
Imagine and ArcGIS
Image source
Date
Landsat 1 MSS
Landsat 5 MSS
Landsat 5 TM
Landsat 5 TM
Landsat 7 ETM+
29-06-1972
14-05-1984
29-05-1998
29-03-2003
04-06-2010
Resolution
[m m]
60.0 60.0
60.0 60.0
30.0 30.0
30.0 30.0
30.0 30.0
20

21. 3. Materials and Methods
3.2 Numerical model
The relocation of fishing harbor to offshore,
groins field system, detached breakwaters and
wide-crested submerged breakwaters were
suggested and examined using the
morphodynamic numerical model of nearshore
waves, currents, and sediment transport in order
to mitigate the coastal erosion (Seif et al., 2011)
21

22. 4. Results and Discussion
4.1 Remote sensing findings
The impact has extended to about 2.5km
to north and to south the harbor
The waterline advanced at the south of
harbor by 0.75 m year-1 and treated at the
north of harbor by 1.15 m year-1
Accretion and erosion rates for the study area
Erosion
Image period area ×103
Accretion
rate ×103
area ×103 rate ×103
[m2]
1972-1984
1984-1998
1998-2003
2003-2010
Total
[m2 year-1]
[m2]
[m2 year-1]
180
200
8
143
531
15
14
2
20
14
122
224
190
70
606
10
16
38
10
16
22

23. 4. Results and Discussion
4.2 Sediment transport rates
 The net annual rate of wave-induced
alongshore sediment transport range from
minimum 160×103 to maximum 220×103 m3,
and the average annual rate of 190×103 m3,
northward
 The sand volume of accretion was estimated
80×103 m3 per year
23

24. 4. Results and Discussion
4.3 Numerical model results
Offshore fishing harbor
model test
4.2
4
3.8
3.6
3.4
3.2
3
0
00
0
0
0
00
0
00
0
200
2.8
400
X(m )
2.6
600
800
1.4
1.2
0.21.4
0
0.6
0.4 0.8
1.2
1
2.2 1.8
2
1.6
1.8 2.4
2.2
2
00
0.2
0.4
1
0.8
200
2.8
0
1.6
2.4
N
400
2.6
X(m)
0
0.2
0.4
0.6
0.6
0
1
0.8
800
1.4
1.2
1m/s
Unit: m
1000
0
1000
0
200
400
600
800
0
1000
200
400
200
7
6
6
5
5 5
5
5
400
X(m )
X(m )
5
600
5
600
4
3
1
800
5
4
3
3
2
2
N
1000
8
7
400
800
0
8
200
600
Y(m)
Y(m )
0
600
1
800
0
0
Unit: m
Unit: m
-1
1000
0
200
400
600
Y(m )
-1
1000
800
1000
0
200
400
600
Y(m )
24
800
1000

25. 25

26. 4. Results and Discussion
4.3 Numerical model results
N
0
200
4.2
4
3.8
3.6
3.4
3.2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
400
400
X(m)
X(m )
200
0
600
600
0.4 0.2
800
1m/s
800
100
200
14
300
400
Y(m )
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
-1
200
400
600
800
0
100
200
300
400
Y(m )
500
0
600
0
200
400
600
Y(m)
14
14
13
12
11
10
9
8
7
6
200
X(m )
0
0.2 0.4
Unit: m
0
0
0
X(m )
Detached breakwater
model test
400
5
4
3
2
1
0
-1
600
Unit: m
500
600
800
0
100
200
300
400
Y(m )
5
Unit:
26 m600
500

27. 4. Results and Discussion
4.3 Numerical model results
N
0
200
400
400
X(m)
m
X( )
200
1.4
1.4
600
600
1.4
1.2
1
0.8
0.6
0.4
0.2
1m/s
0
800
100
200
14
300 400
Y(m )
14
13
12
11
10
9
8
7
6
5
4
200
400
3
2
1
0
-1
600
800
0
100
200
300 400
Y(m )
500
800
0
600
200
400
600
Y(m)
0
14
14
13
12
11
10
9
8
7
6
5
200
m
X( )
0
Unit: m
0
0
m
X( )
Submerged
breakwaters model
test
400
4
2
3
3
2
3
600
1
0
Unit: m
500
600
2
-1
800
0
100
200
300 400
Y(m )
Unit: m
500
27
600

28. 4. Results and Discussion
4.3 Numerical model results
N
0
200
4.2
600
0
800
0
0
0
100
200
14
300
400
Y(m )
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
-1
200
400
600
800
0
100
200
300
400
Y(m )
400
X(m)
400
4
3.8
3.6
3.4
3.2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
600
1m/s
Unit: m
500
800
0
600
200
400
600
Y(m)
0
14
14
13
12
11
10
9
8
7
6
200
X(m )
X(m )
200
X(m )
Groins field system model
test
400
5
4
3
600
Unit: m
500
600
2
1
0
-1
800
0
100
200
300
400
Y(m )
Unit: m
28
500
600

29. 4. Results and Discussion
4.3 Numerical model results
Environmental impact of various mitigation alternatives
Mitigation alternative
Annual rate
[m3 km-1]
Relocation of harbor
Detached BW
Submersed BW
Groins field system
+ 4×103
‒23×103
+28×103
‒22×103
Remarks
Accretion
Erosion
Accretion
Erosion
29

30. 5. Conclusions
 The erosion problem along Gaza beach is due
to the man-made structures as confirmed by
analyzing the historical satellite images from
1972 to 2010
 The numerical model results show that the
offshore harbor is the best alternative for Gaza
beach restoration
 Alternatively, the wide-crested submerged
breakwater, “artificial reef”, is an effective
structure for preventing sandy beach erosion
30

31. References
 Mazen Abualtayef, Ahmed Abu Foul, Ahmed Khaled Seif, Abdel Fattah Abd
Rabou, Omar Matar, Rashad Alhourani, Samir Matar, and Ibrahim Alshiekh.
Mitigation measures for Gaza caostal erosion. 4th International Engineering
Conference, Islamic University of Gaza, Gaza, Palestine, pp 1-13, October
15-16, 2012
 Ahmed Seif. Numerical simulation of 3D morphodynamic around coastal
structures using quasi-3D nearshore current model. Doctorate thesis, Tottori
university, 2011.
 Ahmed Seif, Masamitsu Kuroiwa, Mazen Abualtayef, Hajime Mase, Yuhei
Matsubara. A hydrodynamic model of nearshore waves and wave-induced
currents. Inter. J. Nav. Archit. Oc. Engng, 3(3), 216-224, 2011.
 Burcharth H, Hawkins S, Zanuttigh B, Lamberti A. Environmental design
guidelines for low crested coastal structures, 2007.
 Lee E. Harris, Ph.D., P.E. Investigations and recommendations for solutions
to the beach erosion problems in the city of Herzliya, Israel, 2007.
31

32. References
 Dov Zviely and Micha Klein. The environmental impact of the Gaza Strip
coastal constructions. Journal of coastal research, 19(4), 1122-1127, 2003.
 M. A. Azab and A. M. Noor. Change detection of the North Sinai coast by
using remote sensing and geographic information system, 2003.
 Palestinian National Authority, Ministry of Environmental affairs. Gaza Coastal
and Marine Environmental Protection and Management Action Plan, 2000.
32

33. LOGO
Mrbakr1991@gmail.com
33