<b>Supplementary of Combining geological and historical archives to reconstruct flood variability</b><b>in northwestern Italy</b><b>during the last thousand years</b>

Supplementary material of: "Combining geological and historical archives to reconstruct flood variability in northwestern Italy during the last thousand years"<br><br>Abstract of the paper<br>Understanding Earth’s changing climate is a crucial challenge. However, the available time series ofdirect measurementsare often insufficient to fully capture climatic process that unfolds over centuries and millennia. Combining History and Geology can fill this gap. Focusing on rainfall and flood events, this research proposes a multidisciplinary approach to integrate the sedimentary and meteorological records of the Magra River (Northern Italy), using historical data as a bridge between the two datasets. A pristine record of shallow-water shelf sediments, collected at the mouth of the river and covering the last thousand years, is analysed interpreting sand layers as flood events. The results are compared with a coherent historical record of floods and river activity spanning six centuries and instrumental measurements spanning two centuries. The geological data are reasonably consistent with rainfall data and historical records, testifying for the reliability of the river mouth sedimentary record as a proxy for river discharge. The complete dataset and the comparison with other basin of the northwestern Mediterranean indicate common floods during the second half of the XII, XIV, XVIand XVIIIcenturies, and at the beginning of the second half of the XXcentury, all periods characterised by predominantly negative phases of the North Atlantic Oscillation.