GIS-Based Flood Risk Assessment in Urban Areas: Case Study Amman City

Abstract

Flooding events cause economic, social and environmental damage and lives loss. Flood’s magnitude and its consequences are aggravated by human activities in many circumstances such as urbanization. Wadi Ain Ghazal in Amman city has serious flood problems, yet no integrated flood hazard and risk assessment has previously been developed for the basin. This study addresses that gap by assessing flood hazard and risk in Wadi Ain Ghazal using GIS-Based Spatial Multi Criteria Approach given that flood hazard and risk maps are effective tools for reducing flood damage. Six flood causative factors (elevation, slope, drainage density, land use land cover, manholes, and rainfall) and three elements at risk (population, roads and cropland) were processed and assessed in GIS environment. The Fuzzy Analytic Hierarchy Process approach was used for weighing the factors and combined in a weighted overlay operation to determine the flood hazard and risk. The major findings of the study revealed that most of the lowlands in the downstream part of the sub-basin that is located in the eastern and southwestern parts are within high to very high flood hazard and flood risk level with area coverage close to 27% and 27.5% respectively. The risk assessment of flood and in particular the critical facilities (e.g., hospitals) sheds light on the measures needed by the concerned authorities to formulate their development strategies accordingly. Together, the resulting hazard, vulnerability, and risk maps offer a practical decision-support framework that planners in Amman, and in comparable arid urban basins elsewhere, can apply directly to guide land-use planning and infrastructure investment.