Abstract. The Santa Tecla flash flood, a very heavy event occurred in Tàrrega (Catalonia, NE Iberian Peninsula) in 1874, was reconstructed with hydraulic and hydrological modelling tools. The hydrograph obtained in a first stage and the basin soil moisture information ultimately allowed the estimation of the range of the rainstorm magnitude which caused the flash flood. The reconstruction of historical floods has proved useful to improve the flood probability analysis, especially in ungauged basins.