A Weighted Overlay Analysis for Assessing Urban Flood Risks in Arid Lands: A Case Study of Riyadh, Saudi Arabia

Abstract

Urban flooding poses a significant problem in arid regions, where unusual rainfall events can lead to disastrous consequences. This study used geographic information systems (GIS) to identify and predict potential flood risk zones in Riyadh City, Saudi Arabia. A comprehensive flood risk map was created by integrating various datasets, including digital elevation models (DEM), lithology, precipitation patterns, slope, and drainage density. Through a weighted overlay analysis, Riyadh was segmented into zones with different levels of flood susceptibility, ranging from low to very high risk. The study area spans 905 km2. Of this total area, 32% is at a low risk of flooding, while 31%, 24%, and 12% of the area are at a moderate, high, and very high risk of flooding, respectively. The findings of the study were validated through field surveys conducted before and after recent rainfall events. These validation efforts corroborated the high-risk areas predicted by the model, thereby ensuring the reliability of the map for future urban planning and risk mitigation strategies.

Landscape Analysis and Coastal Planning: Ría de Arosa (Pontevedra, Spain)

“…Specific weights are assigned based on the relative importance or representativeness of each factor and are superimposed to perform an analysis of interrelated data. It demonstrates usefulness in environmental and urban studies where multiple factors interact [21]. In this case, the intrinsic maps, which show greater landscape notoriety, are assigned a weight of 60%, while the extrinsic maps receive a value of 40%.…”

“…Indirect methods rely on techniques such as geographic information systems (GISs), photointerpretation, or consultation of thematic maps (geomorphological, geological, vegetation, etc.). For this study, multicriteria analysis with ArcGis 10.8 is particularly important, as it is successfully used in current environmental studies for territorial planning, landscape analysis, or geological risks [21][22][23]. Additionally, the process of defining landscape units, crucial for obtaining results, makes this methodology highly versatile.…”