Search Results (4)

Soil erosion is one of the most significant problems in global environmental development. Assigning, analyzing, and quantifying the main physical characteristics of drainage basins are powerful keys in identifying regions where there is a higher risk of soil erosion and where prompt mitigation actions are needed. Drainage basins and their drainage systems are ideally defined using the analysis morphometric parameters and their quantitative description. The present study aims to analyze morphometric parameters to prioritize drainage basins that are prone to erosion. Topographic sheets and remotely sensed digital elevation model (DEM) datasets have been prepared and analyzed using geospatial techniques to delineate drainage basins of different sizes and extract different ordered drainage systems. Based on the analysis of morphometric parameters, the Rabigh area was divided into 12 drainage basins, which significantly contribute to determining soil erosion priority levels. The present study selected and applied the most effective morphometric parameters to rank and prioritize the drainage basins of the study area after considering the crucial quantitative characteristics, such as linear, relief, and areal aspects. For each single basin, the compound factor was assigned from several morphometric parameters and applied to rank the Rabigh area. The results confirm that Basins 1, 4, 11, and 12 require a high level of soil erosion priority over an area of 2107 km²; however, Basins 3, 8, 9, and 10 have little degradation and a low level of soil erosion priority. Therefore, in the regions where high soil erosion is a factor, mitigation techniques such as terracing, filter strips, contouring, and other effective and useful structural and non-structural methods should be applied. Full article

Flash flood hazard assessment is a critical component of disaster risk management, particularly in regions vulnerable to extreme rainfall and climatic events. This study focuses on evaluating the flash flood susceptibility of the Rabigh area, located along the Red Sea coast in Makkah province, Saudi Arabia. Using advanced GIS tools and a spatial multi-criteria analysis approach, the research integrates a variety of datasets, including remotely sensed satellite data, the SRTM Digital Elevation Model (DEM), and topographic indices. The main goal was to produce detailed flood susceptibility maps based on the morphometric characteristics of the region’s drainage basins. These basins were delineated and assessed for their flood vulnerability using three distinct modeling techniques, each highlighting different aspects of flood behavior. The results show that the northern basin (Dulaidila) and the central basins (Rabigh, Algud, and Al Nuaibeaa) exhibit the highest flood risk, with significant susceptibility also observed in the southern basins (Ofoq and Saabar). Other basins in the region display moderate susceptibility levels. A key aspect of this analysis was the overlay of the integrated flood susceptibility map with the Topographic Position Index (TPI), a crucial topographic indicator, which helped refine the understanding of flood-prone areas by linking basin morphometry with in-situ topographic features. This study’s comprehensive approach offers valuable insights that can be applied to other coastal regions where hydrological and climatic data are scarce, contributing to more effective flood risk mitigation and strategic planning. Full article

Bottom sediments of Al-Kharrar Lagoon, Rabigh area, Saudi Arabia were analyzed for mineralogical (26 samples) and major oxides, minor, and trace elements (46 samples). The prime objective is to document the controlling factors of the mineralogical and chemical composition of the lagoon bottom sediments. Hierarchical cluster (HCA) and the principal component (PCA) analyses are used to disclose the degree of similarities among elements to distinguish them into statistically significant groups. Results clarified the interplay of terrestrial sediment influx through the temporarily active Wadi Rabigh, hydrological regime and the autochthonous biogenic sedimentation, and to a lesser extent rare anthropogenic influence that impacted the lagoon sediments. The spatial distribution of minerals shows a southward increase in the siliciclastic-related minerals (quartz, clay minerals, k-feldspars, and plagioclase along with traces of amphiboles), whereas carbonate minerals (high Mg-calcite and aragonite) dominate the northern sector of the lagoon in areas far from the influence of detrital influx. The concentrations levels of oxides, minor, and trace elements display spatial variability. Three main distinctive elemental groups were delineated appraising the analysis of the elemental interrelationships and associated statistical analysis. The first group includes the positively correlated SiO₂, TiO₂, Al₂O₃, Fe₂O₃, MnO, MgO, K₂O, Na₂O, V, Cr, Ni, Zn, Rb, and Ba, which are concentrated in the southern sector of the lagoon. The second group is the carbonate-related elements (CaO and Sr) that dominate the northern sector. The distribution patterns of P₂O₅ and Cu varied highly across the lagoon. Enrichment factors revealed moderate levels of Cu in some sites supporting the anthropogenic source. The results showed the hospitable bottom ecological status of the lagoon despite local anthropogenic stressors such as an influx of flood water that contain a mixture of lithogenic and dissolved Cu from local farming. Full article

Mangroves are known as a naturally based solution for climate mitigation and adaptation. Mangroves are at a potential risk of degradation by contaminants such as polycyclic aromatic hydrocarbons (PAHs). In this study, sixteen priority PAHs were analyzed and characterized in forty samples of mangrove seawater and mangrove sediments collected from two coastal areas (i.e., Sharm and Khor Rabigh) along the Red Sea Coast of Rabigh city in August 2013. We found that the average concentration of total PAH in mangrove sediments in the Sharam area (22.09 ng/kg) was higher than that in the Alkhor area (6.51 ng/kg). However, the average concentration of the total PAH in the mangrove seawater in the Alkhor area (9.19 ng/L) was double that in the Sharam area (4.33 ng/L). Phenanthrene and pyrene were the major components in both the mangrove seawater and sediment in all the investigated areas. We observed that the abundance of PAHs with 2–3 aromatic rings was dominant in sediment samples collected from both study areas. This abundance was also observed in seawater from the Sharam area. However, seawater samples from the Alkhor area had abundant PAHs with four aromatic rings. The majority of PAHs in sediment samples of both study areas originated from petrogenic sources, whereas the majority of PAHs in seawater samples originated from pyrogenic sources. Full article