Palaeoflood hydrology: insight into rare events and extreme flood discharges

Floods are the most common type of natural disaster in Europe and, in terms of economic damages, costs are increasing spectacularly with time. In addition to the use of conventional hydrological data, the pre-instrumental flood record can be augmented through 1) palaeoflood hydrology; 2) documentary flood information; or 3) the combined use of both these tools. Palaeoflood hydrology is applied to reconstruct the magnitude and frequency of recent and past floods using geomorphological evidence, such as flood sediments and/or evidence of flood erosion. The sedimentary record of water surface elevation reached by past floods enables the calculation of robust palaeodischarge estimates for floods that occurred during recent centuries or millennia. Recent developments in palaeoflood hydrology in Europe provide : (1) major improvements in flood risk assessment; (2) determination of the maximum limit of flood magnitude and non-exceedences as a check of the probable maximum flood (PMF); and (3) a better understanding of long-term floodclimate relationships.