Impacts of urban growth on flood hazards in Makkah City, Saudi Arabia (original) (raw)
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GIS EVALUATION OF URBAN GROWTH AND FLOOD HAZARDS: A CASE STUDY OF MAKKAH CITY, SAUDI ARABIA
Four-dimensional Geographic Information System (4D GIS) furnishes a noteworthy technical tool for precisely mapping 3D-space growth of urban municipality over time. It can be augmented to estimate flood hazardous impacts due to urban sprawl. In the current study, a 4D GIS has been developed to analyze and quantify both urban growth and flood hazard changes in Makkah city, Saudi Arabia, over the last twenty years. It has been found that the urban growth in 1990 took the north-east and south-west directions, while it took the northwest and south-east directions in 2010. Additionally, investigating the city topography reveals that the urban sprawl mostly exist in low-and moderate-elevation regions. Attained results showed, also, that the residential regions of Makkah city have been increased by 197%, while the total flood volumes have been enlarged by 248%. This is due to two factors: (1) establishment of new residential areas in regions that already posse high flood impacts; and (2) building up new suburban areas on sediment soil that significantly decreases the permeability of the soil and, thus, leads to a crucial increase in hazardous water surface runoff. It is concluded that the utilization of GIS in urban growth and flood hazard estimation studies is quit powerful and provides a successful technical tool that helps in analyzing and understanding such phenomena. It is recommended that the achieved findings should be taken into account by decision-makers in development planning and resources management policies for Makkah metropolitan area.
Flood hazards in an urbanizing watershed in Riyadh, Saudi Arabia
Geomatics, Natural Hazards and Risk, 2014
Riyadh, the capital of the Kingdom of Saudi Arabia, has experienced unusual levels of urbanization in the past few decades, making it one of the fastest growing cities in the world. This paper examines flood hazards in the rapidly urbanizing catchment of Al-Aysen in Riyadh. Remote sensing and geographic information system techniques were employed to obtain and prepare input data for hydrologic and hydraulic models, with the former based on the very popular curve number approach. Due to the limited nature of the rainfall data, observations from two rain gauges in the vicinity of the catchment were used to estimate design storms. The hydrologic model was run in a semi-distributed mode by dividing the catchment into many sub-catchments. The impact of urbanization on runoff volume and peak discharge resulting from different storms was investigated, with various urbanization scenarios simulated. Flood hazard zones and affected streets were also identified through hydrologic/hydraulic model simulation. The mismatch between administrative and catchment boundaries can create problems in flood risk management for similar cities since hydrologic processes and flood hazards are based on the hydrologic connectivity. Since flooding events impact the road network and create driving hazards, governmental decision-makers must take the necessary precautions to protect drivers in these situations.
2019
This study deals with the use of remote sensing (RS), geographic information systems (GISs), hydrologic modeling (water modeling system, WMS), and hydraulic modeling (Hydrologic Engineering Center River Analysis System, HEC-RAS) to evaluate the impact of flash flood hazards on the sustainable urban development of Tabuk City, Kingdom of Saudi Arabia (KSA). Determining the impact of flood hazards on the urban area and developing alternatives for protection and prevention measures were the main aims of this work. Tabuk City is exposed to frequent flash flooding due to its location along the outlets of five major wadis. These wadis frequently carry flash floods, seriously impacting the urban areas of the city. WMS and HEC-HMS models and RS data were used to determine the paths and morphological characteristics of the wadis, the hydrographic flow of different drainage basins, flow rates and volumes, and the expansion of agricultural and urban areas from 1998 to 2018. Finally, hydraulic modeling of the HEC-RAS program was applied to delineate the urban areas that could be inundated with floodwater. Ultimately, the most suitable remedial measures are proposed to protect the future sustainable urban development of Tabuk City from flood hazards. This approach is rarely used in the KSA. We propose a novel method that could help decision-makers and planners in determining inundated flood zones before planning future urban and agricultural development in the KSA.
GIS-Based Spatial Mapping of Flash Flood Hazard in Makkah City, Saudi Arabia
Flash floods occur periodically in Makkah city, Saudi Arabia, due to several factors including its rugged topography and geological structures. Hence, precise assessment of floods becomes a more vital demand in development planning. A GIS-based methodology has been developed for quantifying and spatially mapping the flood characteristics. The core of this new approach is integrating several topographic, metrological, geological, and land use datasets in a GIS environment that utilizes the Curve Number (CN) method of flood modelling for ungauged arid catchments. Additionally, the computations of flood quantities, such as depth and volume of runoff, are performed in the attribute tables of GIS layers, in order to assemble all results in the same environment. The accomplished results show that the runoff depth in Makkah, using a 50-years return period, range from 128.1 mm to 193.9 mm while the peak discharge vary from 1063 m 3 /s to 4489 m 3 /s. The total flood volume is expected to reach 172.97 million m 3 over Makkah metropolitan area. The advantages of the developed methodology include precision, cost-effective, digital outputs, and its ability to be re-run in other conditions.
Makkah City, west of the Kingdom of Saudi Arabia, is considered the third main highly populated metropolitan area in the Kingdom of Saudi Arabia. It exhibits two unique features that increase the hazardous flood consequences: (1) its topography is very complex and (2) about three million Muslims are gathered annually in Makkah to perform Hajj over a 2-week period. Floods are natural returning hydrological phenomena that have been affecting human lives. The objectives of the current study are: (1) identification of land use types and road networks in Makkah, (2) hydrological modeling of flood characteristics in Makkah based on precise up-to-date databases, (3) examination of the relationship between land use, land cover changes, transportation network expansion, and the floods' prosperities and hazards, and (4) development of digital hydrological maps for present and near future flood hazards in Makkah. The attained results show that the mean runoff depth and the total flood volume are significantly increased from 2010 to 2030. Additionally, it has been found that a great part of the road network in Makkah City is subjected to high dangerous flood impacts. The overall length of flood danger-factor roads is increased from 481 km (with almost 37 %) to 1,398 km (with 74 % approximately) between 2010 and 2030. Thus, it is concluded that urbanization has a direct strong relationship with flood hazards. Consequently, it is recommended that the attained results should be taken into account by decision makers in implementing new development planning of the Makkah metropolitan area.
Estimating urban flooding potential near the outlet of an arid catchment in Saudi Arabia
Geomatics, Natural Hazards and Risk, 2016
The aim of this study is to build a flood simulation model for the city of Hafr Al-Batin catchment area. The model consists of a hydrologic model, a hydraulic model and pre-and post-processing tools. A geographic information system-based modelling interface was used to pre-process the terrain and rainfall data and generate input files for hydrologic and hydraulic models. Soil map data, land cover map, land use map and digital elevation model was used to delineate the physical watershed's characteristics. The runoff estimation was based on the widely known Soil Conservation Service curve number approach. The hydrologic/hydraulic model simulations simulated the runoff hydrograph corresponding to different design storms and helped to delineate the resulting flood inundation maps. The results indicate good agreement between the delineated inundation map and the hazard map developed by the municipality. They also show that the location of the city complicates the runoff response for small storms creating two distinct peaks. The results of this study can be utilized for planning purposes and in the design of flood control structures as the study has estimated the runoff corresponding to different design storms and used hydraulics and geospatial data in delineating the flood zones.
Spatio-temporal analysis of urban growth and its impact on floods in Ajman City, UAE
Environmental Monitoring and Assessment, 2019
The negative consequences of urbanisation have been recently recognised despite the social and economic benefits it provides to the community. Effects of urbanisation include increases in surface runoff, frequency and magnitude of floods and urban water harvesting capacity. Accordingly, this study utilised multi-spectral and multi-resolution satellite images combined with field data to conduct a quantitative assessment of the impact of urbanisation on urban flooding for the period of 1975-2015 in Ajman City, United Arab Emirates (UAE). Results showed that urban areas in the city have increased by approximately 12-fold over the period 1975-2015, whilst the population increased by approximately 16-fold. Owing to a substantial increase in urbanisation (as impervious areas expanded), minimum precipitation to generate runoff in built areas dropped from approximately 16.37 mm in 1975 to approximately 13.3 mm in 2015, which caused a substantial increase in the surface runoff. To visualise the flooding potential, urban flooding maps were generated using a well-established decision analysis technique called Analytical Hierarchy Process. The latter adopted three thematic factors, namely excess rain, elevation and slope. Flooding potential was then found to have increased substantially, specifically in the downtown area. Finally, this study is expected to contribute highly to flood protection and sustainable urban storm water management in Ajman City. Keywords Urban growth. Flood mapping. Water harvesting. High-resolution images. Ajman. United Arab Emirates Environ Monit Assess
2012
This paper investigates the development of a hydrological model for the dryland catchment of Wadi Ibrahim, which hosts the Holy Mosque of Makkah, in order to assess the interaction of urbanizing the alluvial channels and the flow discharges of occasional flash floods. The original landscape and landcover of the catchment have witnessed significant changes during the past few decades, where most of the alluvial channels and the mountain footslopes have been covered by urban. The infrequent threat of flash floods has prompted the development of a mitigation measure including; installation of rainfall-sewage system and subsurface culverts, in addition to the conveyance of flows from the upper sub-catchment into another drainage basin. However, the latest flash flood event of 30 of December 2010 has resulted in fatalities and demonstrated the insufficiency of the current mitigation system to control flash floods. The runoff coefficient was estimated from the opportunistic observations a...
International Journal of Sustainable Development and Planning
The climatic changes of the last 20 years generated a high rainfall intensity that lead a common flash flood risks in the wades of arid regions such as Mecca province. However, both the rapid urban expansion in that province and its small catchments trigger the flash flood risk. Therefore, a spatial plan that orient the urban expansion toward less potential flash flood risk has great importance. Such a plan is carried out by a spatial analysis for the topography, rainfall pattern, drainage network density and sub-catchment areas. Geographic Information Systems is a powerful tool in order for achieving that analysis by the overlaying method. Our research guide urban planner to where has urbanization extended. It is a preliminary study for an analytical and numerical runoff modelling that have to be done for the study area in order to clarify the flooding hazard. Our research indicates that catchment area size and drainage network density are the major two factors that control the spatial distribution of flash flooding and need to be consider for any urban spatial plan. We found that the four major cities in Mecca province are threaten by flash flooding differently in terms of direction and intensity.
Geosciences, 2020
Drainage basins in dry and semiarid environments are exposed to sudden, irregular flooding that poses a threat to urban areas and infrastructure. The associated risk is exacerbated by land use changes. Geomorphometric analyses of drainage basins based on geographic information systems (GIS) are essential tools for assessing conceptual flood hazards. Geomorphological data extracted from high-precision digital elevation models (DEMs) provide valuable information for modeling the geomorphic, surface classifications of the earth, and for flood hazard mapping. This study aimed to develop an integrative approach to the mapping of flood hazards along the Al- Shamal train pathway in the city of Qurayyat in the Kingdom of Saudi Arabia (KSA) using GIS and hazard modeling for geomorphological ranking. Furthermore, we propose strategic solutions to provide mitigation and protection from negative impacts with the aim of improving the level of awareness of flood geomorphology. The hazard model of geomorphological ranking was used in mapping and calculating the degree of hazards using 24 geomorphometric criteria. These criteria were divided into formal criteria, terrain criteria, and criteria related to the drainage network. The results of the study revealed that the drainage sub-basins are exposed to flood hazards along the Al-Shamal train pathway in the city of Qurayyat. The very high flood hazard constituted 4228.3 km2, accounting for 70.3% and 65.7%, respectively, of the drainage basins of the wadis of Makhrouq and Bayer. The high flood hazard represented 61% (4712.4 km2) of the basin of the wadis of Sarmadaa. The medium flood hazard was concentrated in the drainage basin of the wadi of Hasidah, accounting for nearly 57.7% (1271.3 km2). The very low flood hazard was present in 46.5% of the drainage basin of the wadis of Hasidah Umm Nakhla, accounting for an area of 799.4 km2. The methodology applied in this study can be used in the estimation of flood hazards in different drainage basins throughout Saudi Arabia and in similar arid regions