The Relationship Between Topography and Flash Floods in Jeddah City by Using GIS and Remote Sensing

Abstract

This research project conducts a comprehensive flood vulnerability assessment in the Jeddah region, Saudi Arabia, focusing on devastating floods that resulted in significant property damage and loss of life. The most serious flood events occurred in 2009 and 2012, which confirms the urgent need to conduct a comprehensive study to find out the factors causing this and search for solutions and ways to manage floods. The project begins with a simple introduction that highlights the ongoing threat of flash floods in Jeddah, underscoring the urgent need for a comprehensive assessment. The primary goal is to develop a reliable flood vulnerability map that identifies areas at risk and assesses their potential impact on urban areas. To achieve this goal, the research uses an effective flood risk analysis methodology, which includes the analysis of various morphometric parameters, including flow number, length, regime, bifurcation ratio, and more. This analysis includes high-resolution ASTER, Digital Terrain Models (DTM) at 30 m resolution, the Topographic Position Index (TPI), and the Topographic Wetness Index (TWI). Geographic Information Systems (GIS) and Remote Sensing (RS) were used to process and visualize spatial data. The data was analyzed using hydrological tools in ArcGIS Pro, and integrating these tools and methodologies revealed that basins B1, B8, and B17 are among the basins most vulnerable to flash floods, while basins B8, B5, B6, B8, and B9 pose the highest risks to urban areas. The resulting flood vulnerability map helps local authorities, researchers and communities understand and manage flood risks and enhance disaster preparedness and response efforts, ultimately contributing to the safety and resilience of the Jeddah region.