دراسة ميدانية لحرکة الرمال ومخاطرها على الطريق الساحلي الليث-القنفذة، غربي المملکة العربية السعودية

This study aims to identify the areas most affected by the movement of sand along the international coastal road between Laith and Al-Qunfudah, in order to reveal the dangers of sand dynamics on road infrastructure and reduce its effects. The results can be used as a model and applied to other roads in Saudi Arabia. The methodology includes the topographical and geological description of the study area, the assessment of the effects of internal sand movement, the performance of several field measurements, the collection of samples and their analysis in the laboratory, as well as the statistical processing of data. The results show the nature of the sand dunes and their types in the study area, where the vegetation cover is very low of the order of (0.1%, i.e. 0.139 km²) of the total area of the research sector.  Through visual analysis of Landsat images from two dates (2000) and (2016), and after a colored composition of the visible and near and mid-infrared bands, it became clear that there are significant changes in land surface conditions This is explained by the geomorphological dynamics of the region on the one hand, and the increase in human activities on the other, confirming the severity of the phenomenon of environmental degradation. The result is the encroachment of dunes of various types on road networks, erosion of the soil surface materialized by a change in its physical and chemical properties, degradation of agricultural land and the burial of houses and roads, proven in the field and in the laboratory. The geomorphological impact and risks caused by the intense activity of the wadis descending from the western slopes of the Hejaz-Aseer mountains, overlooking the Red Sea, and the sediments it carries into the study area for architectural and engineering constructions, land protection and natural disaster management should also be noted.