The Impact of Spatiotemporal Changes in Land Development (1984–2019) on the Increase in the Runoff Coefficient in Erbil, Kurdistan Region of Iraq (original) (raw)

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

Assessing the impact of arid area urbanization on flash floods using GIS, remote sensing, and HEC-HMS rainfall-runoff modeling

2016

This study uses an integrated approach, bringing together geographic information system (GIS), remote sensing, and rainfall-runoff modeling, to assess the urbanization impact on flash floods in arid areas. Runoff modeling was carried out as a function of the catchment characteristics and the maximum daily rainfall parameters. Land-use types were extracted from the supervised classification of SPOT-5 (2010) and Landsat-8 (2015) satellite images and were validated during field checks. Catchment morphometric characteristics were carried out using the correlated Topaz and Arc-Hydro tools. Maximum floods of the catchment were evaluated by coupling GIS and remote sensing with Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) hydrologic modeling. Peak discharges were estimated, and the abstraction losses were computed for different return periods. The model results were calibrated according to actual runoff event. The research shows that rapid urbanization adversely affects hydrological processes, since the sprawl on the alluvial channels is significant. This reduces infiltration into the underlying alluvium and increases runoff, leading to higher flood peaks and volumes even for short duration low intensity rainfall. To retain a considerable amount of water and sediments in these arid areas, construction of small dams at the fingertip channels at the outlet of the lower order sub-basins is recommended.

Determining the Surface Drainage Network Causing Flash Floods in Central Erbil Sub-Basins in Northern Iraq Using GIS and Geospatial Technique

Iraqi geological journal, 2024

This research aimed to identify the most important geomorphological and morphometric properties of the Central Erbil sub-basin and the possibility of benefiting from its water by using it optimally for various uses. The study used the descriptive analytical approach to extract and analyze the morphological and hydrological properties of the valleys in the research area to determine the properties of water drainage networks and variables influencing surface earth formation. Watersheds' morphometric parameters are computed and Identified using Remote Sensing and Geographic Information Systems. Central Erbil sub-basin has radial, parallel, and dendritic drainage patterns and spans 2107 km2. Central Erbil sub-basin is divided into six sub-basins. The present study focused on linear and areal morphometric aspects of sub-basins. The study focuses on morphometric characteristics, for example, drainage density, stream order, stream texture ratio, length, bifurcation ratio, frequency, circularity ratio, form factor ratio, and elongation ratio, which have changed over time. Morphometric studies of the Central Erbil sub-basin indicate that it is a sixth-order drainage basin. This means that the basin is highly permeable and has dense vegetation. Aspects of the basin's morphometric study revealed that it has a significant potential for flooding, suggesting that runoff from the watersheds' upland areas has strongly permeated the basin's gentler downstream portion and increased the capacity for groundwater.

Flood Intensification due to Changes in Land Use

Water Resources Management, 2008

The non-stationarity in runoff regime may be attributed to various causes such as climate change, land use change, and man-made runoff control structures. Degradation of land use can induce significant impact on infiltration and surface roughness leading to higher flood discharges. This study aims at quantifying possible effects of land use changes and identifying flood source areas for future flood control planning in the Golestan watershed located northeast of Iran. A preliminary trend analysis on the annual maximum flood record of three stations inside the watershed showed that two stations were subject to anthropogenic change. This is while no trend could be detected in the annual maximum rainfall records in the region. Using a calibrated event-based rainfall-runoff model, flood hydrographs corresponding to land use conditions in 1967 and 1996 were simulated and relative changes in the peak flow of the two subsequent conditions were determined for different return periods. The results showed that the impact of land use changes on the flood peak discharge is considerably greater in some subwatersheds. Two limiting land use scenarios were also considered to investigate the envelope of future flood peaks in the watershed. By successively eliminating subwatersheds from the simulation process in a method titled "unit flood response", the contribution of each subwatershed to the outlet flood peak was quantified. Contribution, per unit area, to the outlet flood peak was the basis to rank the subwatersheds in terms of their flood potential.

Effects of Land Cover Change on Urban Floods and Rainwater Harvesting: A Case Study in Sharjah, UAE

Water

In this study, multi-temporal satellite images combined with rainfall data and field observations were used to assess the spatial and temporal changes in urban flooding and urban water harvesting potential in the coastal city of Sharjah, United Arab Emirates (UAE) during the period from 1976 to 2016. During the study period, the population increased by approximately 14-fold with about a 4-fold increase in built areas. Being in a hot, dry region with average rainfall of about 100 mm/year, the city did not invest in a comprehensive drainage infrastructure. As a result, the frequency, extent and risk associated with urban floods increased significantly. The expansion of built areas progressively increased the impervious land cover in the city, decreasing the minimum precipitation required to generate runoff by approximately 32% and significantly increasing the runoff coefficient. In parallel to rapid urbanization, the urban rainwater harvesting potential significantly increased over 1976-2016. Urban flood maps were generated using three thematic factors: excess rain, land elevation and land slope. The flood maps were confirmed by locating urban flood locations in the field using GPS. This study demonstrates the impact of urbanization through assessing the relationship between urbanization, runoff, local floods and rainwater harvesting potential in Sharjah and provides a basis for developing sustainable urban storm water management practices for the city and similar cities.

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.

Flood susceptibility mapping utilizing the integration of geospatial and multivariate statistical analysis, Erbil area in Northern Iraq as a case study

Scientific Reports

Climate extreme events such as floods and droughts in any area have a significant impact on human life, infrastructure, agriculture, and the economy. In the last two years, flash floods caused by heavy rainstorms have become frequent and destructive in many catchments in Northern Iraq. The present study aims to examine flash floods in the Erbil region, Northern Iraq using Remote sensing (RS), Geographic Information System (GIS), and Principal Component Analysis (PCA) for geomorphic data. PCA results revealed that 12 geomorphic parameters exhibited a significant correlation with two different statistical components. To facilitate practical application, ranks are assigned based on the calculated parameters for flood susceptibility mapping. Out of the 24 basins in the current study, three basins (16, 3, and 14) have the highest geomorphometric values (36–39), indicating the zone most susceptible to flash floods and making up a maximum area of 38.58% of the studied region. Six basins (4...

Mapping Flash Flood Potential and Risk Level Using GIS Techniques and the Flash Flood Potential Index (FFPI) in Amman Zarqa Basin of Jordan

Jordanian Journal of Engineering and Chemical Industries, 2020

Jordan is located in an arid and semi-arid climatic zone, where about 80% of the country, known as the "Badia". Generally, this is classified as a dry or arid region. Climate change is expected to exacerbate the current aridity and scarcity of water resources in Jordan. Sudden and extreme weather events are becoming more common; this likely means longer and drier summers, more severe droughts, harsher winters, and an increase in flash floods. Jordanian Civil Defense reported that during 1963-2019, 451 people were killed and about one million people affected by flash floods. This research aims to determine the critical locations of flash floods in the Amman Zarqa Basin. This research methodology depends on using four variables (slope, vegetation cover/density, soil type/texture, and land use/cover) under the GIS environment to calculate the Flash Flood Potential Index (FFPI). This index has not been used in Jordan (up to our knowledge). Five scenarios were used in this stud...

GIS-based hydrodynamic modeling for urban flood mitigation in fast-growing regions: a case study of Erbil, Kurdistan Region of Iraq

Scientific Reports

Floods threaten urban infrastructure, especially in residential neighborhoods and fast-growing regions. Flood hydrodynamic modeling helps identify flood-prone locations and improve mitigation plans' resilience. Urban floods pose special issues due to changing land cover and a lack of raw data. Using a GIS-based modeling interface, input files for the hydrodynamic model were developed. The physical basin's properties were identified using soil map data, Land Use Land Cover (LULC) maps, and a Digital Elevation Model (DEM). So, the HEC-RAS 2-D hydrodynamic model was developed to estimate flood susceptibility and vulnerability in Erbil, Iraq. The case study examines the quality of flood modeling results using different DEM precisions. Faced with the difficulty, this study examines two building representation techniques: Building Block (BB) and Building Resistance (BR). The work presented here reveals that it is possible to apply the BR technique within the HEC-RAS 2-D to create ...

Assessment and prediction of land-use/landcover change around Blue Nile and White Nile due to flood hazards in Khartoum, Sudan, based on geospatial analysis

Assessment and prediction of land-uselandcover change around Blue Nile and White Nile due to flood hazards in Khartoum, Sudan, based on geospatial analysis, 2021

Rising floodwaters in the Blue Nile (BN) and White Nile (WN) tributaries continually affects people's lives and the safety of infrastructures in Khartoum, the capital of Sudan. Recently, floods have covered a wide area of Khartoum and destroyed many buildings and bridges. We conducted this study to evaluate and predict the flood effects around BN and WN in Khartoum to make recommendations in view of upcoming flood disasters. Land-use/ land-cover (LULC) changes after floods that occurred in 2014, 2016, and 2020 were evaluated and LULC was predicted for 2024 by applying a combination of remote sensing (RS) and geographic information-system (GIS) techniques. We also evaluated the expected hazard due to floods. Our results showed that the agricultural, built-up, and water changes around BN were 0.30%, 0.25%, and 0.05%, respectively, for the period 2014-2016, and, that changes for the period 2016-2020 were 3.38%, 3.68%, and 7.28%, respectively. Correspondingly, the agricultural, built-up, and water changes around WN were 5.56%, 3.26%, and 8.02% during 2014-2016 and 13.79%, 5.62%, and 21.40% during 2016-2020. The change estimation indicates that the most flood effects in the region occurred around WN, possibly covering the whole areal extent of Khartoum city. The area covered by waterbodies may decrease by 4.18% (BN) and 20.35% (WN) during 2020-2024, based on RS-GIS evaluation, but hydraulic evaluation shows that the expected hazard due to floods in Khartoum is high. Thus, flood-risk assessments should take into account both physical hazard and the distribution of the population across the whole area of Khartoum.