Floods modify the natural dynamics of river environments and greatly affect urban areas, especially in mountain regions where flooding is frequent because of the precipitation characteristics and orographic configuration. In this study the vulnerability of the central sector of the Pyrenees to flood events was investigated using frequency analysis of daily flow and precipitation data for the period from 1940 to 2012 for the headwaters of the Aragón and Ésera rivers. The land use evolution over the past 60 years was also analyzed. The return periods showed that floods have not been exceptional, and the high flow frequency has been large and closely related to precipitation events. This, combined with a large increase in human occupation, particularly since the 1990s, of fluvial areas associated with the land use evolution since 1956, has increased exposure to flood risks.

This study was supported by the Spanish Ministry of Economy and Competitiveness through the projects CGL2015-69985-R, and by the Government of Aragon through the 'programme of research groups' (group Clima, Cambio Global y Sistemas Naturales, BOA 147, 18-12-2002) and ERDF funds.

20 Pags.- 5 Tabls.- 8 Figs. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Peer reviewed