Mapping the potential flood frequency zones in Jordan using Gumbel distribution and GIS

Abstract

Floods are a major natural hazard in Jordan, causing economic and environmental damage. Analysis of extreme values of rainfall data using the Gumbel distribution is a useful method in hydrological applications for flood risk management. This study analyzed 37 years of rainfall data and Gumbel distribution to estimate long-term rainfall and flood frequency. Return durations and exceedance probability were estimated and mapped for probable flood zones for 25, 50, 75, and 100-year intervals. Results suggest maximum yearly rainfalls have a 39-year return period with a 2.5% likelihood of recurrence, while medium rainfalls occur annually with a 97% probability. The results of the spatial analysis indicated that flood frequency, throughout all return periods, was concentrated in the western mountainous regions of the research area, in contrast to the eastern desert areas. This study determined that extreme rainfall events frequently occur in densely populated regions, posing significant flood risks to the population's safety and the sustainability of their economic activities. The findings of this study offer significant insights for decision-makers and planners in mitigating flood risk and facilitating safe, sustainable development in Jordan.