Analytical Hierarchy (AHP) Process Method for Environmental Hazard Mapping for Jeddah City, Saudi Arabia

Abstract

The city of Jeddah, the second major city in the Kingdom of Saudi Arabia (KSA), was severely damaged on November 25, 2009. A deadly and costly flash flood, which can be exacerbated in arid environments, occurred when more than 90 millimetres (3.5 inches) of rain fell in just four hours. A national disaster was declared. This extreme disaster has been a catalyst for attempts to advance our understanding of flash flood events and how to appropriately respond to their destructive nature. One-hundred and twenty people were killed, around 350 others were reported missing and approximately four billion Saudi riyals (one billion US dollars) of damage was caused. Considered to be one of the great of Saudi’s cities, Jeddah is the economic capital of the country. It is the largest coastal town on the west coast, with a population of about 5.1 million and an estimated area of 5460 square kilometres. Based on its rapid urbanisation and population growth, a function of a multitude of parameters, a multi-criterion analysis using AHP and GIS was performed to comprehensively evaluate the environmental quality of the different municipal wards affected by Jeddah’s flash floods. This research presents an analysis of the different factors that caused these flash flood events. The results indicate that the causes of these floods are related to a number of factors that significantly contribute to the worsening of flood disasters.