THE EFFECTS OF SAND ENCROACHMENT ON ROAD TRANSPORT IN MAKKAH REGION

This research aims to evaluate the impact of sand dune movement on land transport routes in the Makkah region. The study analyzes the mechanisms of sand dune formation and their role in the development of dust storms, ultimately modeling the risks posed by sand dunes to roads and classifying these routes based on their level of exposure to such hazards. To achieve this, the research employs a methodology based on geospatial technologies, encompassing data collection and preparation to extract details regarding the factors driving sand dune formation, movement, and their contribution to dust storms and sand drift. The impact of sand dune movement on roads was assessed by modeling the environmental variables that drive these processes and determining the relative importance of each variable using the Analytic Hierarchy Process (AHP). Subsequently, these environmental criteria—weighted according to their significance—were integrated using a cell-based calculation method within a Geographic Information System (GIS) to produce a map of sand dune-related risks to roads, based on eleven distinct environmental criteria. The research findings indicate a variation in the risks posed by sand dune movement to land roads in the Makkah region. This variation stems from the uneven distribution of sand dunes, as well as the environmental systems that drive their formation and dynamics. The level of risk associated with sand dunes and their movement along roads in the region ranges from 23.2%—implying that no road is entirely free from such risks (as the minimum risk value is above zero)—to 98%—indicating that no road is subject to a 100% risk level. Roads in the coastal governorates to the west (specifically Al-Qunfudhah, Al-Lith, Bahrah, and Jeddah) and those in the eastern governorates (Rania, Al-Khurma, and Al-Muwaih)—covering a total length of 1,757.18 km, or 5.66% of the region's total road network—are the most susceptible to the risks of sand dune movement.