A new mountain flood vulnerability index (MFVI) for the assessment of flood vulnerability

The floods are among the most dangerous extreme events. They have affected a large part of the world population. Studies on this topic are needed to understand the phenomenon and prevent the damages. In this context, a new composite indicator was proposed and applied in the Moroccan High Atlas, which is the largest mountain in the Middle East and North African (MENA) countries and one of the most affected. Both the altitude that exceeds 4000 m and the annual rainfall of over 400 mm accelerate the severity of the floods. Climate change and anthropogenic actions have increased the vulnerability to flooding. The variables used in measuring the vulnerability to floods are numerous and interact in a very complex way. Five components (anthropogenic, physical, climatic, lithologic, and land use) and 29 indicators have been selected. The analysis of vulnerability allows identifying the zones and the components with a high degree of vulnerability to floods and proposes the options to reduce it in five selected valleys of the High Atlas; Ourica, De R’dat, Rheraya, Oued N’Fis, and Zat Valleys. The findings suggest that Oued N’Fis may be more vulnerable in terms of climatic indicators while Ourica valley may be vulnerable in terms of the physical, anthropogenic, and lithologic components. However, R’dat valley showed a high vulnerability score regarding the land-use indicators. The total score of flood vulnerability indicates that Ourica is the most vulnerable followed, respectively, by R’dat and Oued N’Fis.