Floods in the Pyrenees region: the PIRAGUA-FLOOD geodatabase

Abstract

<p>The present contribution shows a spatial and temporal analysis of the flood events in the Pyrenees area for the period 1981-2015. Seven regions from Spain, Andorra and France conform the mountain range: Basque Country, Navarra, Aragon and Catalonia, in Spain; Nouvelle-Aquitaine and Occitanie, in France; and Andorra country. Although some flood databases exist for these countries, usually they only include catastrophic flood events for some regions (i.e. FLOODHYMEX – Llasat et al, 2013- include Catalonia and Languedoc-Roussillon). This contribution shows a new flood geodatabase for the whole Pyrenees mountain chain, developed into the framework of the PIRAGUA project (Interreg POCTEFA EFA210/16). In order to have homogeneous information for all the regions, several data sources have been analysed for this period. The methodology used in the database development, the type of information and the structure of the database, are presented. In order to show the localities affected by floods, different maps of the municipal distribution of flood events have been developed. A flood event is defined as an episode along which one or more surface water floods have been recorded in one or more regions. They are usually produced because of heavy rainfall events. Some statistics on temporal distribution, and an identification of the most important events have been carried out. 182 flood events have been identified for the whole region, classified in catastrophic, extraordinary and ordinary flood events. 41 flood events affected more than one region and 9 of them were catastrophic in at least one. 11% of the events caused a total of 140 casualties in the study period, showing the importance of orography and land-use on the exposure of mountainous areas to flood events, especially in flash flood events. Besides punctual information on maximum rainfall provided by meteorological stations, the rainfall field has been analysed from the SAFRAN reanalysis. Finally, the weather types associated to the flood events have been obtained using the Jenkinson and Collison classification (Jenkinson and Collison, 1977).</p><p> </p><p>Jenkinson AF, Collison FP. 1977. An initial climatology of gales over the North Sea. Technical Report, Synoptic climatology Branch Memorandum No. 62, Meteorological Office, Bracknell, UK, 18 pp.</p><p>Llasat MC, Llasat-Botija M, Petrucci O, Pasqua AA, Rosselló J, Vinet F, Boissier L. 2013. Towards a database on societal impact of Mediterranean floods within the framework of the HYMEX project. Nat. Hazards Earth Syst. Sci. 13(5): 1337–1350.</p>