Flood hazards in an urbanizing watershed in Riyadh, Saudi Arabia (original) (raw)
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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.
Impacts of urban growth on flood hazards in Makkah City, Saudi Arabia
academicjournals.org
Flash floods are the most dangerous type of natural disasters in arid regions, such as Saudi Arabia. The effects of urban growth, witnessed between 1990 and 2010, in Makkah city, Saudi Arabia, on runoff volume and peak discharge are investigated using the curve number (CN) flood-modelling methodology. Shapefiles of residential areas are compiled and integrated in a unique geographic information system (GIS) environment. Datasets of geological structures, soil types, and a digital elevation model (DEM) have been collected and utilized. Peak discharges have been computed on the wadi scale, while the total flood volume have been estimated on the sub-basin scale for residential subbasins in order to get a detailed view of urbanization impacts on flood hazards. The results obtained show that the residential regions of Makkah city have been increased, over the period 1990 to 2010, by 197%, while the total flood volumes have been enlarged by 248%. The spatial distribution of high-flood urban regions is mapped. Furthermore, the results show significant positive correlations between urbanization and both peak discharge and flood volume. Accordingly, these findings should be taken into account in future urbanization, sustainable development and flood management plans of Makkah metropolitan area.
GIS-based estimation of flood hazard impacts on road network in Makkah city, Saudi Arabia
Makkah city, Saudi Arabia, is periodically exposed to flash floods that result in major human and economical damages. That is 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 data sets in a geographic information system (GIS) environment that utilizes the curve number method of flood modelling for ungauged arid catchments. Based on the estimated flood volume of sub-basins, a hazard factor has been developed to quantify the expected hazard level for each road. Applying this proposed approach reveals that 21 % of the road network in Makkah city is subjected to low flood hazards, 29 % is facing medium hazards, and 50 % of roads are exposed to harsh flood impacts. The developed approach may be considered a digital precise method that can be easily re-run, in other situations or regions, to estimate flood hazards on roads.
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.
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...
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.
Sustainability, 2019
The current study aimed at measuring the impact of the change in land-use morphology on the increase of flood risk through its application to the case of the Riyadh–Dammam train track in Saudi Arabia. The track was exposed to drift on 18 February 2017, over a length of 10 km, in the district of Dhahran in the capital of Dammam. Flooding caused the train to drift off its track and resulted in damage to lives, property, and infrastructure. This resulted from human interventions in the preplanning land uses and changing the morphology of the land by encroaching on the valleys, which resulted in the loss of the environmental and ecological balance in the study area .In order to achieve these goals, land-use changes in the study area were monitored by analyzing successive images from the GEO-I-1 satellite with a resolution of 60 cm for the years 2011 and 2017, before and after the train drift, using the maximum likelihood classification process provided in ERDAS IMAGINE 2016. GIS was used in the processing of 1 m digital elevation models to extract the morphological changes of the wadies between 2011 and 2017. A hydrological model (HEC– HMS) was used in calculating the (flood) hydrograph curve of the wadies basins and estimating the calculation of flood water quantities and its flow rates based on the Soil Conservation Services (SCS) Unit Hydrograph Method. Rain depth was analyzed and estimated for different return periods. The HEC–RAS hydraulic modeling program was employed in developing a 2D model to calculate the velocity, depth, and spread of the flood in order to apply the risk matrix method.
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
International Journal of GEOMATE, 2020
This study aims to evaluate and identify potential floods in coastal areas with simple slopes of the Al-Lith valley basin, and to identify urban areas exposed to flooding with flood water in the coastal city of Al-Lith during the period between 1988-2019 as a model for the coastal city of Saudi Arabia, and designing strategies to mitigate the effects of floods and the establishment of a Department of Urban Planning Flood Risk. These are very important things for political and planning decision-makers, as the city suffers from repeated exposure to the risk of floods as a result of its occurrence directly below the Al-Lith valley basin. In order to reach these goals, the (Light Detection and Ranging, Lidar) data was analyzed to build and develop a twodimensional model of the depth, speed and spread of water using a hydraulic model (Hydrologic Engineering Center-River Analysis System, HEC-RAS) to calculate the risk matrix of floods. Changes in Earth's use of the city of Al-Lith were monitored by analyzing consecutive satellite visualizations made by the American satellite Landsat in the years 1988, 2000, 2013, and 2019. The hydrological model (Hydrologic Engineering Center-Hydrologic Modelling System, HEC-HMS) was applied in calculating the floods hydrograph curve for the Al-Lith Valley basin during different return periods, and estimating the calculation of the amounts of flood water and flow rates depending on the (SCS Unit Hydrograph) method.