A multidisciplinary methodology for historical floods reconstruction was applied to 1874 Santa Tecla floods occurred in Catalonia (NE Iberian Peninsula), using both historical information and meteorological data from 20th Century Reanalysis. The results confirmed the exceptionality of the event: the highest modeled specific peak flow was around 14.6 m3 s1 km2 in a 100 km2 catchment and all the modeled total rainfall values were above 110 mm in about six hours, with maximum intensities around 60 mm min1 . The peak-flows peak flows’ return periods were about 260 years and the rainfalls periods were between 250 and 500 years. The meteorological cause of the rainstorms was the flash triggering effect, initiated by the withdrawal of a mass of hot air at mid-levels. A sensitivity analysis on the various sources of error shows that peak flow errors from hydraulic modeling ranged from 5% to 44%, and rainfall errors from hydrological modeling were about 36%.

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