Classification of the flood severity of the Guadalquivir River in the Southwest of the Iberian Peninsula during the 13th to 19th centuries

This study estimates the pluviometric evolution between the 13th and 19th centuries on the southwestern Iberian Peninsula based on the historic records of the impacts of the Guadalquivir River flooding on the city of Seville (Spain). The main documentary source was “Critical history of the floods of the Guadalquivir in Seville”, published in 1878, which compiles news from different observers, who were contemporaries of each event. Regarding the methodology, it was necessary to transfer the information from different documentary sources to ordinal indices, which required developing allocation criteria per flood impact. From the annual assigned flood index, an interannual series was generated. Moreover, for the last decades of the 21st century, quantifying the flooding levels in the records allowed us to relate them directly to instrumental records of rainfall and establish a relationship between these two phenomena. Through interannual weighing of the flooding indices, it was possible to deduce the durations and intensities of sequences of rainy periods between 1250 and 1850. This allowed us to reconstruct the pluviometric evolution. Of the ten floods classified as most destructive during the five centuries analysed, i.e., from 1280 to 1880, five occurred during little more than a century (1598-1701). The obtained results contribute to knowledge on regional rainfall, as well as to historical climatology and hydrology, over multiple centuries.