12
30.5.2012 1 Khalid Al‐Ghamdi, Meraj Mirza, Ramze Elzahrany, and Gomaa M. Dawod Umm Al‐Qura University, Saudi Arabia Saudi Arabia FIG Working Week, Italy, May 6-10, 2012 2
30.5.2012
1
Khalid Al‐Ghamdi, Meraj Mirza, RamzeElzahrany, and GomaaM. Dawod
Umm Al‐Qura University, Saudi Arabia
Saudi Arabia
FIG Working Week, Italy, May 6-10, 2012 2
30.5.2012
2
Makkah City
It is a unique city for Muslims all over the world, since it contains the holly mosque.
From a religious point of view, a Muslim should perform pilgrimage (called Hajj, i.e., visiting Makkah in specific days in the year) once in his/her life.
Thus, hundreds of thousands Muslims are gathered in Makkah yearly.
This is an important factor to be considered in analysing the urban growth of this city.
FIG Working Week, Italy, May 6-10, 2012 3
FIG Working Week, Italy, May 6-10, 2012 4
30.5.2012
3
FIG Working Week, Italy, May 6-10, 2012 5
30.5.2012
4
FIG Working Week, Italy, May 6-10, 2012 7
Floods in Makkah
Periodical
Flash (high intensity in short time)
Dangerous
7
Rainfall History
FIG Working Week, Italy, May 6-10, 2012 8
0
50
100
150
200
250
300
350
19
66
19
68
19
70
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
20
06
20
08
20
10
Year
An
nu
al R
ain
(m
m)
30.5.2012
5
FIG Working Week, Italy, May 6-10, 2012 9
Topography of Makkah
Mountainous rigid topography
Heights: 138 to 982 m (average: 276 m)
Runoff comes mainly from interior wadis
9
FIG Working Week, Italy, May 6-10, 2012 10
Objectives
Utilizing GIS:
1. To monitor and quantify the spatial urban sprawl of Makkah city 1947‐2010
2. To estimate flood hazards' increase over the same period
3. To investigate the urban sprawl ‐flood hazards' increase relationship.
10
30.5.2012
6
Available Data
Maps:
1. Topographic map of Makkah city in 1947
2. 105 cadastral maps (AutoCAD files) for 1990
3. A land use map dated 2010
and
A national 5‐meter resolution DEM
FIG Working Week, Italy, May 6-10, 2012 11
Flood Estimation
Using the U.S National Resources Conservation Service (NRCS) Curve Number (CN) methedologloy.
It utilizes geological/Soil/Land use informationto assign a unique CN coefficient for each sub‐basin
CN used to estimate the surface runoff depth and the peak discharge magnitude.
FIG Working Week, Italy, May 6-10, 2012 12
30.5.2012
7
Processing Workflow
FIG Working Week, Italy, May 6-10, 2012 13
Results1. Urban growth:
FIG Working Week, Italy, May 6-10, 2012 14
30.5.2012
8
Results2. Urban growth and topography:
FIG Working Week, Italy, May 6-10, 2012 15
Results3. Urban growth and road network:
FIG Working Week, Italy, May 6-10, 2012 16
30.5.2012
9
Results4. Urban growth and geology:
FIG Working Week, Italy, May 6-10, 2012 17
Results5. Floods in 1990:
FIG Working Week, Italy, May 6-10, 2012 18
30.5.2012
10
Results6. Floods in 2010:
FIG Working Week, Italy, May 6-10, 2012 19
Results7. Floods vs. Urban growth (1990‐2010):
FIG Working Week, Italy, May 6-10, 2012 20
30.5.2012
11
FIG Working Week, Italy, May 6-10, 2012 21
Results
FIG Working Week, Italy, May 6-10, 2012 22
Results
30.5.2012
12
Conclusions
1. Urban growth in Makkah city = 97% from 1990 to 2010 (with 5% annual rate).
2. Urban sprawl mainly exist in low- and moderate-elevation regions.
3. Urban development has been intensive mostly along main two highways.
4. Establishment of new residential areas was in regions that already posse high flood impacts
5. Building up new suburban areas on sediment soil significantly decreases the permeability of the soil and, thus, leads to a crucial increase in hazardous water surface runoff.
FIG Working Week, Italy, May 6-10, 2012 23
FIG Working Week, Italy, May 6-10, 2012 24
